DEFF Research Database (Denmark)
Karakatsani, Eirini; Kontogeorgis, Georgios; Economou, Ioannis
2006-01-01
Perturbed chain-statistical associating fluid theory (PC-SAFT) was extended rigorously to polar fluids based on the theory of Stell and co-workers [Mol. Phys. 1977, 33, 987]. The new PC-PSAFT was simplified to truncated PC-PSAFT (tPC-PSAFT) so that it can be practical for real polar fluid...
ADSORPTION OF ASSOCIATING FLUIDS AT ACTIVE SURFACES: A DENSITY FUNCTIONAL THEORY
Directory of Open Access Journals (Sweden)
S.Tripathi
2003-01-01
Full Text Available We present a density functional theory (DFT to describe adsorption in systems where molecules of associating fluids can bond (or associate with discrete, localized functional groups attached to the surfaces, in addition to other fluid molecules. For such systems as water adsorbing on activated carbon, silica, clay minerals etc. this is a realistic model to account for surface heterogeneity rather than using a continuous smeared surface-fluid potential employed in most of the theoretical works on adsorption on heterogeneous surfaces. Association is modelled within the framework of first order thermodynamic perturbation theory (TPT1. The new theory accurately predicts the distribution of bonded and non-bonded species and adsorption behavior under various conditions of bulk pressure, surface-fluid and fluid-fluid association strengths. Competition between the surface-fluid and fluid-fluid association is analyzed for fluids with multiple association sites and its impact on adsorption is discussed. The theory, supported by simulations demonstrates that the extent and the nature of adsorption (e.g. monolayer vary with the number of association sites on the fluid molecules.
Institute of Scientific and Technical Information of China (English)
许波; 李浩然; 王从敏; 许映杰; 韩世钧
2005-01-01
1H NMR chemical shifts of binary aqueous mixtures of acylamide, alcohol, dimethyl sulphoxide (DMSO), and acetone are correlated by statistical associating fluid theory (SAFT) association model. The comparison between SAFT association model and Wilson equation shows that the former is better for dealing with aqueous solutions. Finally, the specialties of both models are discussed.
Investigation of Vapor-Liquid Nucleation for Associating Fluids by Density Gradient Theory
Institute of Scientific and Technical Information of China (English)
FU Dong; LIU Jianmin
2009-01-01
An equation of state (EOS) applicable to both the uniform and non-uniform associating fluids was established by using the density-gradient expansion, in which the influence parameter κis formulated as a function of tempera-ture. The molecular parameters were regressed by fitting to the experimental data of vapor pressures and liquid den-sities. Within the framework of density gradient theory (DGT), the nucleation rates for water, heavy water, metha-nol, ethanol, 1-propanoi, 1-butanol, 1-pentanol and 1-hexanol were calculated. The results were satisfactory com-pared with the experimental data. Our study shows that DGT preserves all the advantages of density functional the-ory (DFT) in capturing the structure and properties of nucleus but gives much more accurate nucleation rates by adjusting the influence parameter.
Modeling of aqueous electrolyte solutions with perturbed-chain statistical associated fluid theory
DEFF Research Database (Denmark)
Cameretti, Luca F.; Sadowski, Gabriele; Mollerup, Jørgen
2005-01-01
The vapor pressures and liquid densities of single-salt electrolyte solutions containing NaCl, LiCl, KCl, NaBr, LiBr, KBr, NaI, LiI, KI, Li2SO4, Na2SO4, and K2SO4 were modeled with an equation of state based on perturbed-chain statistical associated fluid theory (PC-SAFT). The PC-SAFT model...... was extended to charged compounds using a Debye-Huckel term for the electrostatic interactions. Two model parameters for each ion were fitted to experimental pVT and vapor-pressure data. The model is able to excellently reproduce the experimental data up to high salt molalities and even to predict vapor...
Almasi, Mohammad
2014-11-01
Densities and viscosities for binary mixtures of Diethanolamine (DEA) + 2 alkanol (2 propanol up to 2 pentanol) were measured over the entire composition range and temperature interval of 293.15-323.15 K. From the density and viscosity data, values of various properties such as isobaric thermal expansibility, excess isobaric thermal expansibility, partial molar volumes, excess molar volumes and viscosity deviations were calculated. The observed variations of these parameters, with alkanols chain length and temperature, are discussed in terms of the intermolecular interactions between the unlike molecules of the binary mixtures. The ability of the perturbed chain statistical associating fluid theory (PC-SAFT) to correlate accurately the volumetric behavior of the binary mixtures is demonstrated.
Jiang, Hao; Panagiotopoulos, Athanassios Z.; Economou, Ioannis G.
2016-03-01
Statistical associating fluid theory (SAFT) is used to model CO2 solubilities in single and mixed electrolyte solutions. The proposed SAFT model implements an improved mean spherical approximation in the primitive model to represent the electrostatic interactions between ions, using a parameter K to correct the excess energies ("KMSA" for short). With the KMSA formalism, the proposed model is able to describe accurately mean ionic activity coefficients and liquid densities of electrolyte solutions including Na+, K+, Ca2+, Mg2+, Cl-, Br- and SO42- from 298.15 K to 473.15 K using mostly temperature independent parameters, with sole exception being the volume of anions. CO2 is modeled as a non-associating molecule, and temperature-dependent CO2-H2O and CO2-ion cross interactions are used to obtain CO2 solubilities in H2O and in single ion electrolyte solutions. Without any additional fitting parameters, CO2 solubilities in mixed electrolyte solutions and synthetic brines are predicted, in good agreement with experimental measurements.
DEFF Research Database (Denmark)
Liang, Xiaodong; Kontogeorgis, Georgios
2015-01-01
The Perturbed Chain-Statistical Associating Fluid Theory Equation of State (PC-SAFT EOS) has been successfully applied to model phase behavior of various types of systems, while it is also well-known that the PC-SAFT EOS has difficulties in describing some second-order derivative properties. In t...
Energy Technology Data Exchange (ETDEWEB)
Ji Peijun [College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029 (China); Feng Wei [College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029 (China)]. E-mail: fengwei@mail.buct.edu.cn; Tan Tianwei [College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029 (China)
2007-07-15
The density of aqueous solutions of amino acids has been modeled with the statistical associating fluid theory (SAFT) equation of state. The modeling is accomplished by extending the previously developed new method to determine the SAFT parameters for amino acids. The modeled systems include {alpha}-alanine/H{sub 2}O, {beta}-alanine/H{sub 2}O, proline/H{sub 2}O, L-asparagine/H{sub 2}O, L-glutamine/H{sub 2}O, L-histidine/H{sub 2}O, serine/H{sub 2}O, glycine/H{sub 2}O, alanine/H{sub 2}O/sucrose, DL-valine/H{sub 2}O/sucrose, arginine/H{sub 2}O/sucrose, serine/H{sub 2}O/ethylene glycol, and glycine/H{sub 2}O/ethylene glycol. The density of binary solutions of amino acids has been correlated or predicted with a high precision. And then the density of multicomponent aqueous solutions of amino acids has been modeled based on the modeling results of binary systems, and a high accuracy of density calculations has been obtained. Finally, the water activities of DL-valine/H{sub 2}O, glycine/H{sub 2}O, and proline/H{sub 2}O have been predicted without using binary interaction parameters, and good results have been obtained.
DEFF Research Database (Denmark)
Grenner, Andreas; Tsivintzelis, Ioannis; Economou, Ioannis;
2008-01-01
A standard database for the validation of vapor-liquid equilibrium (VLE) models was used to evaluate prediction and correlation accuracy of the nonrandom hydrogen bonding (NRHB) theory and the simplified perturbed-chain-statistical associating fluid theory (PC-SAFT). Pure-component parameters...... for the models were taken from literature or estimated in this work. Generalized pure-component parameters were fitted to pure-component vapor-pressure and liquid-density data. For the majority of the mixtures examined, satisfactory results were obtained. For a number of mixtures, different modeling approaches...
Gripaios, Ben
2014-01-01
The quantum theory of fields is largely based on studying perturbations around non-interacting, or free, field theories, which correspond to a collection of quantum-mechanical harmonic oscillators. The quantum theory of an ordinary fluid is `freer', in the sense that the non-interacting theory also contains an infinite collection of quantum-mechanical free particles, corresponding to vortex modes. By computing a variety of correlation functions at tree- and loop-level, we give evidence that a quantum perfect fluid can be consistently formulated as a low-energy, effective field theory. We speculate that the quantum behaviour is radically different to both classical fluids and quantum fields, with interesting physical consequences for fluids in the low temperature regime.
Quantum Field Theory of Fluids
Gripaios, Ben; Sutherland, Dave
2015-01-01
The quantum theory of fields is largely based on studying perturbations around non-interacting, or free, field theories, which correspond to a collection of quantum-mechanical harmonic oscillators. The quantum theory of an ordinary fluid is `freer', in the sense that the non-interacting theory also contains an infinite collection of quantum-mechanical free particles, corresponding to vortex modes. By computing a variety of correlation functions at tree- and loop-level, we give evidence that a...
Institute of Scientific and Technical Information of China (English)
许波; 李浩然; 王从敏; 许映杰; 韩世钧
2005-01-01
1H NMR chemical shifts of binary aqueous mixtures of acylamide, alcohol, dimethyl sulphoxide (DMSO), and acetone are correlated by statistical associating fluid theory (SAFT) association model. The comparison between SAFT association model and Wilson equation shows that the former is better for dealing with aqueous solutions. Finally, the specialties of both models are discussed.
Effective field theory of dissipative fluids
Crossley, Michael; Liu, Hong
2015-01-01
We develop an effective field theory for dissipative fluids which governs the dynamics of gapless modes associated to conserved quantities. The system is put in a curved spacetime and coupled to external sources for charged currents. The invariance of the hydrodynamical action under gauge symmetries and diffeomorphisms suggests a natural set of dynamical variables which provide a mapping between an emergent "fluid spacetime" and the physical spacetime. An essential aspect of our formulation is to identify the appropriate symmetries in the fluid spacetime. Our theory applies to nonlinear disturbances around a general density matrix. For a thermal density matrix, we require an additional Z_2 symmetry, to which we refer as the local KMS condition. This leads to the standard constraints of hydrodynamics, as well as a nonlinear generalization of the Onsager relations. It also leads to an emergent supersymmetry in the classical statistical regime, with a higher derivative version required for the full quantum regim...
Mathematical theory of compressible fluid flow
Von Mises, Richard
2012-01-01
Mathematical Theory of Compressible Fluid Flow covers the conceptual and mathematical aspects of theory of compressible fluid flow. This five-chapter book specifically tackles the role of thermodynamics in the mechanics of compressible fluids. This text begins with a discussion on the general theory of characteristics of compressible fluid with its application. This topic is followed by a presentation of equations delineating the role of thermodynamics in compressible fluid mechanics. The discussion then shifts to the theory of shocks as asymptotic phenomena, which is set within the context of
DEFF Research Database (Denmark)
Ferreira, Luisa; Breil, Martin Peter; Pinho, S. P.;
2009-01-01
The perturbed-chain statistical associated fluid theory EoS was applied to model the solubilities of glycine, DL-alanine, L-serine, L-threonine, and L-isoleucine in pure water, pure alcohols (ethanol, I-propanol, and 2-propanol) and in mixed solvent systems. Three pure component nonassociating...... parameters for the amino acids were fitted to the densities, activity and osmotic coefficients, vapor pressures, and water activity of their aqueous solutions. The solubilities of amino acids in pure and mixed solvent systems were calculated on the basis of the phase equilibrium conditions for a pure solid...... and a fluid phase. The hypothetical melting properties of each amino acid were fitted, to accurately correlate the solubilities in pure water. Only one temperature independent binary parameter is required for each amino acid/solvent pair. The model can accurately describe the solubility of the amino acids...
Fluid dynamics theory, computation, and numerical simulation
Pozrikidis, C
2001-01-01
Fluid Dynamics Theory, Computation, and Numerical Simulation is the only available book that extends the classical field of fluid dynamics into the realm of scientific computing in a way that is both comprehensive and accessible to the beginner The theory of fluid dynamics, and the implementation of solution procedures into numerical algorithms, are discussed hand-in-hand and with reference to computer programming This book is an accessible introduction to theoretical and computational fluid dynamics (CFD), written from a modern perspective that unifies theory and numerical practice There are several additions and subject expansions in the Second Edition of Fluid Dynamics, including new Matlab and FORTRAN codes Two distinguishing features of the discourse are solution procedures and algorithms are developed immediately after problem formulations are presented, and numerical methods are introduced on a need-to-know basis and in increasing order of difficulty Matlab codes are presented and discussed for a broad...
Fluid Dynamics Theory, Computation, and Numerical Simulation
Pozrikidis, Constantine
2009-01-01
Fluid Dynamics: Theory, Computation, and Numerical Simulation is the only available book that extends the classical field of fluid dynamics into the realm of scientific computing in a way that is both comprehensive and accessible to the beginner. The theory of fluid dynamics, and the implementation of solution procedures into numerical algorithms, are discussed hand-in-hand and with reference to computer programming. This book is an accessible introduction to theoretical and computational fluid dynamics (CFD), written from a modern perspective that unifies theory and numerical practice. There are several additions and subject expansions in the Second Edition of Fluid Dynamics, including new Matlab and FORTRAN codes. Two distinguishing features of the discourse are: solution procedures and algorithms are developed immediately after problem formulations are presented, and numerical methods are introduced on a need-to-know basis and in increasing order of difficulty. Matlab codes are presented and discussed for ...
DEFF Research Database (Denmark)
Tsivintzelis, Ioannis; Grenner, Andreas; Economou, Ioannis;
2008-01-01
Two statistical thermodynamic models, the nonrandom hydrogen bonding (NRHB) theory, which is a compressible lattice model, and the simplified perturbed-chain-statistical associating fluid theory (sPC-SAFT), which is based on Wertheim's perturbation theory, were used to model liquid......-liquid equilibria and predict the fraction of nonhydrogen bonded molecules in various hydrogen bonding mixtures. Carefully selected binary mixtures, which include water-hydrocarbon, 1-alkanol-hydrocarbon, water-1-alkanol, and glycol-hydrocarbon, were used to benchmark the accuracy of the models. Both models yielded...... for the treatment of hydrogen bonding, yielded similar predictions for the fraction of non-hydrogen bonded molecules (monomer fraction) in pure 1-alkanols and in 1-alkanol-n-hexane mixtures....
Statistical mechanical theory of fluid mixtures
Zhao, Yueqiang; Wu, Zhengming; Liu, Weiwei
2014-01-01
A general statistical mechanical theory of fluid mixtures (liquid mixtures and gas mixtures) is developed based on the statistical mechanical expression of chemical potential of components in the grand canonical ensemble, which gives some new relationships between thermodynamic quantities (equilibrium ratio Ki, separation factor α and activity coefficient γi) and ensemble average potential energy u for one molecule. The statistical mechanical expressions of separation factor α and activity coefficient γi derived in this work make the fluid phase equilibrium calculations can be performed by molecular simulation simply and efficiently, or by the statistical thermodynamic approach (based on the saturated-vapor pressure of pure substance) that does not need microscopic intermolecular pair potential functions. The physical meaning of activity coefficient γi in the liquid phase is discussed in detail from a viewpoint of molecular thermodynamics. The calculated Vapor-Liquid Equilibrium (VLE) properties of argon-methane, methanol-water and n-hexane-benzene systems by this model fit well with experimental data in references, which indicates that this model is accurate and reliable in the prediction of VLE properties for small, large and strongly associating molecules; furthermore the statistical mechanical expressions of separation factor α and activity coefficient γi have good compatibility with classical thermodynamic equations and quantum mechanical COSMO-SAC approach.
Mathematical theory of compressible fluid flow
von Mises, Richard
2004-01-01
A pioneer in the fields of statistics and probability theory, Richard von Mises (1883-1953) made notable advances in boundary-layer-flow theory and airfoil design. This text on compressible flow, unfinished upon his sudden death, was subsequently completed in accordance with his plans, and von Mises' first three chapters were augmented with a survey of the theory of steady plane flow. Suitable as a text for advanced undergraduate and graduate students - as well as a reference for professionals - Mathematical Theory of Compressible Fluid Flow examines the fundamentals of high-speed flows, with
Schreckenberg, Jens M. A.; Dufal, Simon; Haslam, Andrew J.; Adjiman, Claire S.; Jackson, George; Galindo, Amparo
2014-09-01
An improved formulation of the extension of the statistical associating fluid theory for potentials of variable range to electrolytes (SAFT-VRE) is presented, incorporating a representation for the dielectric constant of the solution that takes into account the temperature, density and composition of the solvent. The proposed approach provides an excellent correlation of the dielectric-constant data available for a number of solvents including water, representative alcohols and carbon dioxide, and it is shown that the methodology can be used to treat mixed-solvent electrolyte solutions. Models for strong electrolytes of the metal-halide family are considered here. The salts are treated as fully dissociated and ion-specific interaction parameters are presented. Vapour pressure, density, and mean ionic activity coefficient data are used to determine the ion-ion and solvent-ion parameters, and mixed-salt electrolyte solutions (brines) are then treated predictively. We find that the resulting intermolecular potential models follow physical trends in terms of energies and ion sizes with a close relationship observed with well-established ionic diameters. A good description is obtained for the densities, mean ionic activity coefficients, and vapour pressures of the electrolyte solutions studied. The theory is also seen to provide excellent predictions of the osmotic coefficient and of the depression of the freezing temperature, and provides a qualitative estimate of the solvation free energy. The vapour pressure of aqueous brines is predicted accurately, as is the density of these solutions, although not at the highest pressures considered. Calculations for the vapour-liquid and liquid-liquid equilibria of salts in water+methanol and water+n-butan-1-ol are presented. In addition, it is shown that the salting-out of carbon dioxide in sodium chloride solutions is captured well using a predictive model.
Generalized fluid theory including non-Maxwellian kinetic effects
Izacard, Olivier
2016-01-01
The results obtained by the plasma physics community for the validation and the prediction of turbulence and transport in magnetized plasma come mainly from the use of very CPU-consuming particle-in-cell or (gyro)kinetic codes which naturally include non-Maxwellian kinetic effects. To date, fluid codes are not considered to be relevant for the description of these kinetic effects. Here, after revisiting the limitations of the current fluid theory developed in the 19th century, we generalize the fluid theory including kinetic effects such as non-Maxwellian super-thermal tails with as few fluid equations as possible. The collisionless and collisional fluid closures from the nonlinear Landau Fokker-Planck collision operator are shown for an arbitrary collisionality. Indeed, the first fluid models associated with two examples of collisionless fluid closures are obtained by assuming an analytic non-Maxwellian distribution function (e.g., the INMDF [O. Izacard, Phys. Plasmas 23, 082504 (2016)]). One of the main dif...
Neves, Catarina M S S; Held, Christoph; Mohammad, Sultan; Schleinitz, Miko; Coutinho, João A P; Freire, Mara G
2015-12-21
Due to scarce available experimental data, as well as due to the absence of predictive models, the influence of salts on the solubility of ionic liquids (ILs) in water is still poorly understood. To this end, this work addresses the solubility of the IL 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C4C1im][NTf2]), at 298.15 K and 0.1 MPa, in aqueous salt solutions (from 0.1 to 1.5 mol kg(-1)). At salt molalities higher than 0.2 mol kg(-1), all salts caused salting-out of [C4C1im][NTf2] from aqueous solution with their strength decreasing in the following order: Al2(SO4)3 > ZnSO4 > K3C6H5O7 > KNaC4H4O6 > K3PO4 > Mg(CH3CO2)2 > K2HPO4 > MgSO4 > KH2PO4 > KCH3CO2. Some of these salts lead however to the salting-in of [C4C1im][NTf2] in aqueous medium at salt molalities lower than 0.2 mol kg(-1). To attempt the development of a model able to describe the salt effects, comprising both the salting-in and salting-out phenomena observed, the electrolyte Perturbed-Chain Statistical Associating Fluid Theory (ePC-SAFT) was applied using ion-specific parameters. The gathered experimental data was modelled using ePC-SAFT parameters complemented by fitting a single binary parameter between K(+) and the IL-ions to the IL solubility in K3PO4 aqueous solutions. Based on this approach, the description of anion-specific salting-out effects of the remaining potassium salts was found to be in good agreement with experimental data. Remarkably, ePC-SAFT is even able to predict the salting-in effect induced by K2HPO4, based on the single K(+)/IL-ions binary parameter which was fitted to an exclusively salting-out effect promoted by K3PO4. Finally, ePC-SAFT was applied to predict the influence of other sodium salts on the [C4C1im][NTf2] solubility in water, with experimental data taken from literature, leading to an excellent description of the liquid-liquid phase behaviour.
Relativistic fluid formulation and theory of intense relativistic electron beams
International Nuclear Information System (INIS)
A new general relativistic fluid formulation has been obtained for intense relativistic electron beams (IREB) with arbitrarily high relativistic mass factor γ. This theory is valid for confined IREB equilibria such as those found inside high energy accelerators as well as in the pinched and ion-focused regimes of beam propagation in plasma channels. The new relativistic fluid formulation is based on the covariant relativistic fluid formulation of Newcomb with the parameter lambda identical to 1, in order to allow for realistic confined equilibria. The resulting equilibrium constraints require that the beam has a slow rotational velocity around its direction of propagation and that the off-diagonal thermal stress element, associated with these two directions of motion, be nonzero. The effective betatron oscillation frequency of the fluid elements of the beam is modified by the radial gradient and anisotropies in the thermal stress elements of the beam fluid. The wave equation, for sausage, hose and filamentation excitations on the relativistic fluid beam, is found to be formally identical to that obtained from the Vlasov equation approach, hence phase-mixing damping is a generic and self-consistent correlate of the new relativistic fluid formulation
Quasi-chemical Theories of Associated Liquids
Pratt, Lawrence R.; LaViolette, Randall A.
1998-01-01
It is shown how traditional development of theories of fluids based upon the concept of physical clustering can be adapted to an alternative local clustering definition. The alternative definition can preserve a detailed valence description of the interactions between a solution species and its near-neighbors, i.e., cooperativity and saturation of coordination for strong association. These clusters remain finite even for condensed phases. The simplest theory to which these developments lead i...
Association theories for complex thermodynamics
DEFF Research Database (Denmark)
Kontogeorgis, Georgios; Rafiqul Gani
2013-01-01
Thermodynamics of complex systems (e.g. with associating molecules, multicomponent mixtures, multiphase equilibria, wide ranges of conditions, estimation of many different properties simultaneously) is a topic of great importance in chemical engineering and for a wide range of industrial applicat......Thermodynamics of complex systems (e.g. with associating molecules, multicomponent mixtures, multiphase equilibria, wide ranges of conditions, estimation of many different properties simultaneously) is a topic of great importance in chemical engineering and for a wide range of industrial...... applications. While specialized models can handle different cases, even complex ones, with the advent of powerful theories and computers there is the hope that a single or a few models could be suitable for a general modeling of complex thermodynamics. After more than 100 years with active use of thermodynamic...... models, we have now come to the understanding that simple one-fluid theories like the cubic equations of state or the various forms of local composition models will never be able to model a wide range of complex systems with sufficient accuracy. While various modern approaches have appeared, one very...
Simple bond length dependence: A correspondence between reactive fluid theories
Dyer, Kippi M.; Perkyns, John S.; Pettitt, B. M.
2005-06-01
Two elementary models of reactive fluids are examined, the first being a standard construction assuming molecular dissociation at infinite separation; the second is an open mixture of nondissociative molecules and free atoms in which the densities of free atoms and molecules are coupled. An approximation to the density of molecules, to low order in site density, is derived in terms of the classical associating fluid theory variously described by Wertheim [J. Chem. Phys. 87, 7323 (1987)] and Stell [Physica A 231, 1 (1996)]. The results are derived for a fluid of dimerizing hard spheres, and predict dependence of the molecular density on the total site density, the hard sphere diameter, and the bond length of the dimer. The results for the two reactive models are shown to be qualitatively similar, and lead to equivalent predictions of the molecular density for the infinitely short and infinitely long bond lengths.
Quasi-chemical Theories of Associated Liquids
Pratt, L R; Pratt, Lawrence R.; Violette, Randall A. La
1998-01-01
It is shown how traditional development of theories of fluids based upon the concept of physical clustering can be adapted to an alternative local clustering definition. The alternative definition can preserve a detailed valence description of the interactions between a solution species and its near-neighbors, i.e., cooperativity and saturation of coordination for strong association. These clusters remain finite even for condensed phases. The simplest theory to which these developments lead is analogous to quasi-chemical theories of cooperative phenomena. The present quasi-chemical theories require additional consideration of packing issues because they don't impose lattice discretizations on the continuous problem. These quasi-chemical theories do not require pair decomposable interaction potential energy models. Since calculations may be required only for moderately sized clusters, we suggest that these quasi-chemical theories could be implemented with computational tools of current electronic structure the...
Bansal, Artee; Cox, Kenneth R; Chapman, Walter G
2016-01-01
A mixture of solvent particles with short-range, directional interactions and solute particles with short-range, isotropic interactions that can bond multiple times is of fundamental interest in understanding liquids and colloidal mixtures. Because of multi-body correlations predicting the structure and thermodynamics of such systems remains a challenge. Earlier Marshall and Chapman developed a theory wherein association effects due to interactions multiply the partition function for clustering of particles in a reference hard-sphere system. The multi-body effects are incorporated in the clustering process, which in their work was obtained in the absence of the bulk medium. The bulk solvent effects were then modeled approximately within a second order perturbation approach. However, their approach is inadequate at high densities and for large association strengths. Based on the idea that the clustering of solvent in a defined coordination volume around the solute is related to occupancy statistics in that def...
Bansal, Artee; Asthagiri, D; Cox, Kenneth R; Chapman, Walter G
2016-08-21
A mixture of solvent particles with short-range, directional interactions and solute particles with short-range, isotropic interactions that can bond multiple times is of fundamental interest in understanding liquids and colloidal mixtures. Because of multi-body correlations, predicting the structure and thermodynamics of such systems remains a challenge. Earlier Marshall and Chapman [J. Chem. Phys. 139, 104904 (2013)] developed a theory wherein association effects due to interactions multiply the partition function for clustering of particles in a reference hard-sphere system. The multi-body effects are incorporated in the clustering process, which in their work was obtained in the absence of the bulk medium. The bulk solvent effects were then modeled approximately within a second order perturbation approach. However, their approach is inadequate at high densities and for large association strengths. Based on the idea that the clustering of solvent in a defined coordination volume around the solute is related to occupancy statistics in that defined coordination volume, we develop an approach to incorporate the complete information about hard-sphere clustering in a bulk solvent at the density of interest. The occupancy probabilities are obtained from enhanced sampling simulations but we also develop a concise parametric form to model these probabilities using the quasichemical theory of solutions. We show that incorporating the complete reference information results in an approach that can predict the bonding state and thermodynamics of the colloidal solute for a wide range of system conditions.
Bansal, Artee; Asthagiri, D.; Cox, Kenneth R.; Chapman, Walter G.
2016-08-01
A mixture of solvent particles with short-range, directional interactions and solute particles with short-range, isotropic interactions that can bond multiple times is of fundamental interest in understanding liquids and colloidal mixtures. Because of multi-body correlations, predicting the structure and thermodynamics of such systems remains a challenge. Earlier Marshall and Chapman [J. Chem. Phys. 139, 104904 (2013)] developed a theory wherein association effects due to interactions multiply the partition function for clustering of particles in a reference hard-sphere system. The multi-body effects are incorporated in the clustering process, which in their work was obtained in the absence of the bulk medium. The bulk solvent effects were then modeled approximately within a second order perturbation approach. However, their approach is inadequate at high densities and for large association strengths. Based on the idea that the clustering of solvent in a defined coordination volume around the solute is related to occupancy statistics in that defined coordination volume, we develop an approach to incorporate the complete information about hard-sphere clustering in a bulk solvent at the density of interest. The occupancy probabilities are obtained from enhanced sampling simulations but we also develop a concise parametric form to model these probabilities using the quasichemical theory of solutions. We show that incorporating the complete reference information results in an approach that can predict the bonding state and thermodynamics of the colloidal solute for a wide range of system conditions.
Meta fluid dynamic as a gauge field theory
Mendes, A C R; Oliveira, W; Takakura, F I
2003-01-01
In this paper, the analog of Maxwell electromagnetism for hydrodynamic turbulence, the meta fluid dynamics, is extended in order to reformulate the meta fluid dynamics as a gauge field theory. That analogy opens up the possibility to investigate this theory as a constrained system. Having this possibility in mind, we propose a Lagrangian to describe this new theory of turbulence and, subsequently, analyze it from the symplectic point of view. From this analysis, a hidden gauge symmetry is revealed, providing a clear interpretation and meaning of the physics behind the meta fluid theory. Also, the geometrical interpretation to the gauge symmetries is discussed.
Fluid Mechanics An Introduction to the Theory of Fluid Flows
Durst, Franz
2008-01-01
Advancements of fluid flow measuring techniques and of computational methods have led to new ways to treat laminar and turbulent flows. These methods are extensively used these days in research and engineering practise. This also requires new ways to teach the subject to students at higher educational institutions in an introductory manner. The book provides the knowledge to students in engineering and natural science needed to enter fluid mechanics applications in various fields. Analytical treatments are provided, based on the Navier-Stokes equations. Introductions are also given into numerical and experimental methods applied to flows. The main benefit the reader will derive from the book is a sound introduction into all aspects of fluid mechanics covering all relevant subfields.
Towards Predictive Association Theories
DEFF Research Database (Denmark)
Kontogeorgis, Georgios; Tsivintzelis, Ioannis; Michelsen, Michael Locht;
2011-01-01
Association equations of state like SAFT, CPA and NRHB have been previously applied to many complex mixtures. In this work we focus on two of these models, the CPA and the NRHB equations of state and the emphasis is on the analysis of their predictive capabilities for a wide range of applications...
Theory of locomotion through complex fluids
Elfring, Gwynn
2014-01-01
Microorganisms such as bacteria often swim in fluid environments that cannot be classified as Newtonian. Many biological fluids contain polymers or other heterogeneities which may yield complex rheology. For a given set of boundary conditions on a moving organism, flows can be substantially different in complex fluids, while non-Newtonian stresses can alter the gait of the microorganisms themselves. Heterogeneities in the fluid may also be characterized by length scales on the order of the organism itself leading to additional dynamic complexity. In this chapter we present a theoretical overview of small-scale locomotion in complex fluids with a focus on recent efforts quantifying the impact of non-Newtonian rheology on swimming microorganisms.
Institute of Scientific and Technical Information of China (English)
SUN Zong-Li; KANG Yan-Shuang
2011-01-01
Classical density functional theory is used to study the associating Lennard Jones fluids in contact with spherical hard wall of different curvature radii. The interfacial properties including contact density and fluid-solid interfacial tension are investigated. The influences of associating energy, curvature of hard wall and the bulk density of Huids on these properties are analyzed in detail. The results may provide helpful clues to understand the interfacial properties of other complex fluids.%@@ Classical density functional theory is used to study the associating Lennard Jones fluids in contact with spherical hard wall of different curvature radii.The interfacial properties including contact density and fluid-solid intcrfacial tension are investigated.The influences of associating energy, curvature of hard wall and the hulk density of fluids on these properties are analyzed in detail.The results may provide helpful clues to understand the interfacial properties of other complex fluids.
The Einstein static universe in Scalar-Fluid theories
Boehmer, Christian G.; Tamanini, Nicola; Wright, Matthew
2015-01-01
A new Lagrangian framework has recently been proposed to describe interactions between relativistic perfect fluids and scalar fields. In this paper we investigate the Einstein static universe in this new class of theories, which have been named Scalar-Fluid theories. The stability of the static solutions to both homogeneous and inhomogeneous perturbations is analysed deriving the relevant cosmological perturbation equations at the linear order. We can find several configurations corresponding...
Field theory of the Eulerian perfect fluid
Ariki, Taketo
2016-01-01
An action formalism is developed for the perfect fluid in the Eulerian framework, where theoretical flaws related with the Clebsch parametrization are removed. The proposed formalism naturally leads us to interactions of 2 types. One is the gauge interaction on the Clebsch potentials, which yields the non-Abelian (Abelian) fluid dynamics in a pure manner of the gauge principle. The other is the interaction on the velocity potentials which convert the rest-mass energy to energies of other fields and vise versa.
Modern Fluid Dynamics Intermediate Theory and Applications
Kleinstreuer, Clement
2010-01-01
Features pedagogical elements that include consistent 50/50 physics-mathematics approach when introducing material, illustrating concepts, showing flow visualizations, and solving problems. This title intends to help serious undergraduate student solve basic fluid dynamics problems independently, and suggest system design improvements
Pleural fluids associated with chest infection.
Quadri, Amal; Thomson, Anne H
2002-12-01
Pleural effusions are commonly associated with pneumonias and a small number of these progress to empyema. An understanding of the physiology and pathophysiology of pleural fluid aids the clinician in the management of empyema. There remains much debate about the optimal treatment of empyema in children. Early recognition of the condition is important since delayed therapy may result in unnecessary morbidity. Conventional management with high dose parenteral antibiotics and chest tube drainage remains the mainstay of therapy. However, this treatment modality may fail if the pleural fluid becomes viscous and loculated and, therefore, a more aggressive approach is required. Intrapleural fibrinolytic therapy has been shown to decrease the length of hospital stay and may reduce the need for surgical intervention. The prognosis in children with parapneumonic empyema is excellent with the vast majority retaining normal lung function at long term follow-up.
Fluctuation theory of critical phenomena in fluids
Martynov, G. A.
2016-07-01
It is assumed that critical phenomena are generated by density wave fluctuations carrying a certain kinetic energy. It is noted that all coupling equations for critical indices are obtained within the context of this hypothesis. Critical indices are evaluated for 15 liquids more accurately than when using the current theory of critical phenomena.
Electrorheological fluids modeling and mathematical theory
Růžička, Michael
2000-01-01
This is the first book to present a model, based on rational mechanics of electrorheological fluids, that takes into account the complex interactions between the electromagnetic fields and the moving liquid. Several constitutive relations for the Cauchy stress tensor are discussed. The main part of the book is devoted to a mathematical investigation of a model possessing shear-dependent viscosities, proving the existence and uniqueness of weak and strong solutions for the steady and the unsteady case. The PDS systems investigated possess so-called non-standard growth conditions. Existence results for elliptic systems with non-standard growth conditions and with a nontrivial nonlinear r.h.s. and the first ever results for parabolic systems with a non-standard growth conditions are given for the first time. Written for advanced graduate students, as well as for researchers in the field, the discussion of both the modeling and the mathematics is self-contained.
Editorial Viscoplastic fluids: From theory to application 2013
Chateau, Xavier; Wachs, A
2015-01-01
International audience q This issue of the Journal of Non-Newtonian Fluid Mechanics includes a series of papers based on work presented at the international workshop on Viscoplastic fluids: from theory to application, held Nov. 18–21, 2013 in Rueil Malmaison, France. A list of participants is provided in Table 1. This was the fifth biannual meeting on this subject. The previous meetings were held in Banff (Alberta, Canada), Monte Verita (Ascona, Switzerland), Limassol (Cyprus) and Rio de J...
Unified dark fluid in Brans-Dicke theory
Tripathy, Sunil K.; Behera, Dipanjali; Mishra, Bivudutta(Department of Mathematics, Birla Institute of Technology and Science-Pilani, Hyderabad Campus, 500078, Hyderabad, India)
2014-01-01
Anisotropic dark energy cosmological models are constructed in the frame work of generalised Brans–Dicke theory with a self-interacting potential. A unified dark fluid characterised by a linear equation of state is considered as the source of dark energy. The shear scalar is considered to be proportional to the expansion scalar simulating an anisotropic relationship among the directional expansion rates. The dynamics of the universe in the presence of a unified dark fluid in anisotropic backg...
Rate constitutive theories for ordered thermoviscoelastic fluids: polymers
Surana, K. S.; Nunez, D.; Reddy, J. N.; Romkes, A.
2014-03-01
This paper presents development of rate constitutive theories for compressible as well as in incompressible ordered thermoviscoelastic fluids, i.e., polymeric fluids in Eulerian description. The polymeric fluids in this paper are considered as ordered thermoviscoelastic fluids in which the stress rate of a desired order, i.e., the convected time derivative of a desired order ` m' of the chosen deviatoric Cauchy stress tensor, and the heat vector are functions of density, temperature, temperature gradient, convected time derivatives of the chosen strain tensor up to any desired order ` n' and the convected time derivative of up to orders ` m-1' of the chosen deviatoric Cauchy stress tensor. The development of the constitutive theories is presented in contravariant and covariant bases, as well as using Jaumann rates. The polymeric fluids described by these constitutive theories will be referred to as ordered thermoviscoelastic fluids due to the fact that the constitutive theories are dependent on the orders ` m' and ` n' of the convected time derivatives of the deviatoric Cauchy stress and conjugate strain tensors. The highest orders of the convected time derivative of the deviatoric Cauchy stress and strain tensors define the orders of the polymeric fluid. The admissibility requirement necessitates that the constitutive theories for the stress tensor and heat vector satisfy conservation laws, hence, in addition to conservation of mass, balance of momenta, and conservation of energy, the second law of thermodynamics, i.e., Clausius-Duhem inequality must also be satisfied by the constitutive theories or be used in their derivations. If we decompose the total Cauchy stress tensor into equilibrium and deviatoric components, then Clausius-Duhem inequality and Helmholtz free-energy density can be used to determine the equilibrium stress in terms of thermodynamic pressure for compressible fluids and in terms of mechanical pressure for incompressible fluids, but the second
Perturbation theories for the thermodynamic properties of fluids and solids
Solana, J R
2013-01-01
This book, Perturbation Theories for the Thermodynamic Properties of Fluids and Solids, provides a comprehensive review of current perturbation theories-as well as integral equation theories and density functional theories-for the equilibrium thermodynamic and structural properties of classical systems. Emphasizing practical applications, the text avoids complex theoretical derivations as much as possible. It begins with discussions of the nature of intermolecular forces and simple potential models. The book also presents a summary of statistical mechanics concepts and formulae. In addition, i
Introduction to the theory of fluid and magnetofluid turbulence
International Nuclear Information System (INIS)
This set of notes was transcribed from the tape recording of three lectures given at the Institute of Plasma Physics, Nagoya University, in June, 1983. The lectures were intended to provide an introduction to the theory of magnetofluid turbulence which is a relatively new branch of plasma physics. It is related more closely to classic fluid dynamics than to the nonlinear theory of plasma oscillation. For this reason, fluid turbulence theory was reviewed as the background of the subject. The first lecture is on the origins of fluid and magnetofluid turbulence. The universal transition to turbulence takes place at sufficiently high Reynolds number, well above the critical threshold. The second lecture is on closures, attempt on dynamical theories. The Navier-Stokes case is discussed, and the attempt to reduce the number of the degrees of freedom, the importance of helicity in MHD, the direct interaction approximation (DIA) and others are explained. The third lecture is on the cascade and inverse cascade in fluid and magnetofluid. The idea of cascade was introduced into the theory of Navier-Stokes turbulence around 1941. The calculation of a form for inertial range energy spectra, the relation with dissipation rate, the tendency of migrating to long wavelength, the simulation of decaying turbulence, the numbers characterizing MHD and others are discussed. (Kako, I.)
Investigating models for associating fluids using spectroscopy
DEFF Research Database (Denmark)
von Solms, Nicolas; Michelsen, Michael Locht; Passos, Claudia Pereira;
2005-01-01
Two equations of state (PC-SAFT and CPA) are used to predict the monomer fraction of pure associating fluids. The models each require five pure-component parameters usually obtained by fitting to experimental liquid density and vapor pressure data. Here we also incorporate monomer fractions......-site schemes perform about equally for ethanol; for higher alcohols a two-site scheme is preferred. This is in accordance with steric arguments. Some difficulties in the interpretation of spectroscopic data and their comparison with the predictions of association models are illustrated. Apparently anomalous...... measured using spectroscopy, resulting in models that better predict the monomer fraction (fraction of molecules not participating in hydrogen bonding), without sacrificing the accuracy of the liquid density and vapor pressure correlations. Thus, it is clear that monomer fraction prediction depends on the...
Vapour-to-Liquid Nucleation in Associating Lennard-Jones Fluids with Multiple Association Sites
Institute of Scientific and Technical Information of China (English)
FU Dong; LIAO Tao
2007-01-01
The excess Helmholtz free energy functional for associating Lennard-Jones (LJ) fluid is formulated in terms of a weighted density approximation for short-ranged interactions and a Weeks Chandler-Andersen approximation for long-range attraction. Within the framework of density functional theory, phase equilibria, vapour-liquid surface tension and vapour-liquid nucleation properties including the density profile, work of formation, excess number of particles and critical supersaturation are investigated for associating LJ fluids with different numbers of association sites (M=1,2,3,4) per particle. The influences of association energy and association sites on phase equilibria, surface tension and vapour-liquid nucleation properties are discussed.
Thermodynamics of perfect fluids from scalar field theory
Ballesteros, Guillermo; Comelli, Denis; Pilo, Luigi
2016-07-01
The low-energy dynamics of relativistic continuous media is given by a shift-symmetric effective theory of four scalar fields. These scalars describe the embedding in spacetime of the medium and play the role of Stückelberg fields for spontaneously broken spatial and time translations. Perfect fluids are selected imposing a stronger symmetry group or reducing the field content to a single scalar. We explore the relation between the field theory description of perfect fluids to thermodynamics. By drawing the correspondence between the allowed operators at leading order in derivatives and the thermodynamic variables, we find that a complete thermodynamic picture requires the four Stückelberg fields. We show that thermodynamic stability plus the null-energy condition imply dynamical stability. We also argue that a consistent thermodynamic interpretation is not possible if any of the shift symmetries is explicitly broken.
Thermodynamics of perfect fluids from scalar field theory
Ballesteros, Guillermo; Pilo, Luigi
2016-01-01
The low-energy dynamics of relativistic continuous media is given by a shift-symmetric effective theory of four scalar fields. These scalars describe the embedding in spacetime of the medium and play the role of Stuckelberg fields for spontaneously broken spatial and time translations. Perfect fluids are selected imposing a stronger symmetry group or reducing the field content to a single scalar. We explore the relation between the field theory description of perfect fluids to thermodynamics. By drawing the correspondence between the allowed operators at leading order in derivatives and the thermodynamic variables, we find that a complete thermodynamic picture requires the four Stuckelberg fields. We show that thermodynamic stability plus the null energy condition imply dynamical stability. We also argue that a consistent thermodynamic interpretation is not possible if any of the shift symmetries is explicitly broken.
Theory of fluid slip in charged capillary nanopores
Catalano, J; Biesheuvel, P M
2016-01-01
Based on the capillary pore model (space-charge theory) for combined fluid and ion flow through cylindrical nanopores or nanotubes, we derive the continuum equations modified to include wall slip. We focus on the ionic conductance and streaming conductance, cross-coefficients of relevance for electrokinetic energy conversion and electro-osmotic pumping. We combine the theory with a Langmuir-Stern 1-pK charge regulation boundary condition resulting in a non-monotonic dependence of the cross-coefficients on salt concentration.
Theory of chain association versus liquid condensation
Roij, R. van
1996-01-01
We combine the original van der Waals description for liquid condensation with the association theory of ideal particles into a simple association theory of nonideal chains. The theory shows that vapor-liquid coexistence becomes metastable if the tendency to form weakly interacting chains is suffici
Fully Lagrangian Renormalized Approximation theory of fluid turbulence: Progress report
International Nuclear Information System (INIS)
The purpose of this paper is to discuss our refinement and extension of the work of Y. Kaneda on a Lagrangian Renormalized Approximation (LRA) for homogeneous hydrodynamic turbulence. Kaneda's results are important to the development of a consistent theory of turbulence because the LRA theory successfully overcomes the failure of other turbulence theories (namely the Direct Interaction Approximation) to predict the Kolmogorov wavenumber spectrum. It is thought that this success is due to the use of a Lagrangian rather than Eulerian description of the fluid so that convection of the small eddies by the large ones is properly treated. However, some aspects of these results are puzzling and are considered here. For example, the form of the correlation function and the value of the Kolmogorov constant, K, depend on the choice of the form of the correlation function
Global Fluorine Flux Associated with Submarine Hydrothermal Fluids
Kagoshima, T.; Sano, Y.
2015-12-01
We estimated a fluorine flux associated with hydrothermal fluid emission at mid-ocean ridges (MOR) based on vent fluid chemistry and MORB vesicle compositions. Multiplication of fluorine concentrations in submarine hydrothermal fluids and the vent fluid flux at MOR may give us an estimate of fluorine flux at MOR. A worldwide vent chemistry research [1] suggested that submarine vent fluids are depleted in fluorine (Elsevier, London). [2] Coogan & Dosso (2012) EPSL 323-324, 92-101. [3] Kagoshima et al. (2014) Japan Geoscience Union Meeting 2014 Abstract #SGC56-P01. [4] Fischer (2008) Geochem. J. 42, 21-38.
Geometrodynamical Fluid Theory Applied to Dynamo Flows in Planetary Interiors
Lewis, Kayla; Miramontes, Diego; Scofield, Dillon
2015-11-01
Due to their reliance on a Newtonian viscous stress model, the traditional Navier-Stokes equations are of parabolic type; this in turn leads to acausal behavior of solutions to these equations, e.g., a localized disturbance at any point instantaneously affects the solution arbitrarily far away. Geometrodynamical fluid theory (GFT) avoids this problem through a relativistically covariant formulation of the flow equations. Using GFT, we derive the magnetohydrodynamic equations describing the balance of energy-momentum appropriate for dynamo flows in planetary interiors. These equations include interactions between magnetic and fluid vortex fields. We derive scaling laws from these equations and compare them with scaling laws derived from the traditional approach. Finally, we discuss implications of these scalings for flows in planetary dynamos.
Unified dark fluid in Brans-Dicke theory
Energy Technology Data Exchange (ETDEWEB)
Tripathy, Sunil K. [Indira Gandhi Institute of Technology, Department of Physics, Dhenkanal, Odisha (India); Behera, Dipanjali [Government College of Engineering, Department of Physics, Kalahandi, Odisha (India); Mishra, Bivudutta [Birla Institute of Technology and Science-Pilani, Department of Mathematics, Hyderabad (India)
2015-04-01
Anisotropic dark energy cosmological models are constructed in the frame work of generalised Brans-Dicke theory with a self-interacting potential. A unified dark fluid characterised by a linear equation of state is considered as the source of dark energy. The shear scalar is considered to be proportional to the expansion scalar simulating an anisotropic relationship among the directional expansion rates. The dynamics of the universe in the presence of a unified dark fluid in anisotropic background have been discussed. The presence of an evolving scalar field makes it possible to get an accelerating phase of expansion even for a linear relationship among the directional Hubble rates. It is found that the anisotropy in expansion rates does not affect the scalar field, the self-interacting potential, but it controls the non-evolving part of the Brans-Dicke parameter. (orig.)
Effective string theory for vortex lines in fluids and superfluids
Horn, Bart; Penco, Riccardo
2015-01-01
We discuss the effective string theory of vortex lines in ordinary fluids and low-temperature superfluids, by describing the bulk fluid flow in terms of a two-form field to which vortex lines can couple. We derive the most general low-energy effective Lagrangian that is compatible with (spontaneously broken) Poincare invariance and worldsheet reparameterization invariance. This generalizes the effective action developed by Lund and Regge and by Endlich and Nicolis. By applying standard field-theoretical techniques, we show that certain low-energy coupling constants -- most notably the string tension -- exhibit RG running already at the classical level. We discuss applications of our techniques to the study of Kelvin waves, vortex rings, and the coupling to bulk sound modes.
Institute of Scientific and Technical Information of China (English)
FU Dong; YAN Shu-Mei; WANG Xue-Min
2008-01-01
The excess Helmholtz free energy functional for four-site associating Lennard-Jones(LJ)fluid was formulated in terms of a modified fundamental measure theory for short-ranged interactions and a first-order mean-spherical approximation theory for long-ranged attraction.Within the framework of density functional theory,the thermodynamic properties including the average density isotherms,density profiles and fractions of not bonded monomers characterizing the coexistences between gas-like and liquid-like phases for capillary condensation,phase equilibria and equilibrium plate-fluid interfacial tensions were investigated.The influences of association energy,fluid-solid interaction and pore width on the inhomogeneous behavior of four-site associating LJ fluids confined in slit pores were discussed.
Use of Monomer Fraction Data in the Parametrization of Association Theories
DEFF Research Database (Denmark)
Kontogeorgis, Georgios; Tsivintzelis, Ioannis; von Solms, Nicolas;
2010-01-01
Association theories such as the CPA (cubic-plus-association), NRHB (non-random hydrogen bonding) equations of state and the various variants of SAFT (statistical associating fluid theory) have been extensively applied to phase equilibrium calculations. Such models can also be used for estimating...
Interactions of some fluids with dark energy in f(T) theory
Nassur, S. B.; Houndjo, M. J. S.; Salako, I. G.; Tossa, J.
2016-01-01
We investigate the interaction of the dark energy with some fluids filling the universe in the framework of $f(T)$ theory, where $T$ denotes the torsion scalar, searching for the associated gravitational actions. Dark energy is assumed to be of gravitational origin. The interaction of dark energy and baryonic matter is considered resulting in a decay of the energy density of the ordinary matter, where universe appears as driven by cosmological constant. Furthermore we consider the interaction...
Mirigian, Stephen; Schweizer, Kenneth S.
2014-05-01
We generalize the force-level nonlinear Langevin equation theory of single particle hopping to include collective effects associated with long range elastic distortion of the liquid. The activated alpha relaxation event is of a mixed spatial character, involving two distinct, but inter-related, local and collective barriers. There are no divergences at volume fractions below jamming or temperatures above zero Kelvin. The ideas are first developed and implemented analytically and numerically in the context of hard sphere fluids. In an intermediate volume fraction crossover regime, the local cage process is dominant in a manner consistent with an apparent Arrhenius behavior. The super-Arrhenius collective barrier is more strongly dependent on volume fraction, dominates the highly viscous regime, and is well described by a nonsingular law below jamming. The increase of the collective barrier is determined by the amplitude of thermal density fluctuations, dynamic shear modulus or transient localization length, and a growing microscopic jump length. Alpha relaxation time calculations are in good agreement with recent experiments and simulations on dense fluids and suspensions of hard spheres. Comparisons of the theory with elastic models and entropy crisis ideas are explored. The present work provides a foundation for constructing a quasi-universal, fit-parameter-free theory for relaxation in thermal molecular liquids over 14 orders of magnitude in time.
Mirigian, Stephen; Schweizer, Kenneth S
2014-05-21
We generalize the force-level nonlinear Langevin equation theory of single particle hopping to include collective effects associated with long range elastic distortion of the liquid. The activated alpha relaxation event is of a mixed spatial character, involving two distinct, but inter-related, local and collective barriers. There are no divergences at volume fractions below jamming or temperatures above zero Kelvin. The ideas are first developed and implemented analytically and numerically in the context of hard sphere fluids. In an intermediate volume fraction crossover regime, the local cage process is dominant in a manner consistent with an apparent Arrhenius behavior. The super-Arrhenius collective barrier is more strongly dependent on volume fraction, dominates the highly viscous regime, and is well described by a nonsingular law below jamming. The increase of the collective barrier is determined by the amplitude of thermal density fluctuations, dynamic shear modulus or transient localization length, and a growing microscopic jump length. Alpha relaxation time calculations are in good agreement with recent experiments and simulations on dense fluids and suspensions of hard spheres. Comparisons of the theory with elastic models and entropy crisis ideas are explored. The present work provides a foundation for constructing a quasi-universal, fit-parameter-free theory for relaxation in thermal molecular liquids over 14 orders of magnitude in time. PMID:24852549
Theory of trapped-particle-induced resistive fluid turbulence
International Nuclear Information System (INIS)
A theory of anomalous electron heat transport, evolving from trapped-particle-induced resistive interchange modes, is proposed. These latter are a new branch of the resistive interchange-ballooning family of instabilities, destabilized when the pressure carried by the unfavorably-drifting trapped particles is sufficiently large to overcome stabilizing contributions coming from favorable average curvature. Expressions for the turbulent heat diffusivity and anomalous electron thermal conductivity at saturation are derived for two regimes of trapped particle energy: (1) a moderately-energetic regime, which is ''fluid-like'' in the sense that the unstable mode grows faster than the time that it takes for particles in this energy range to precess once around the torus; and (2) a highly-energetic regime, where the trapped species has sufficiently high energy as to be able to resonantly interact with the mode. Unlike previous theories of anomalous transport, the estimates of diffusion and transport obtained here are self-consistent, since the trapped particles do not ''see'' the magnetic flutter due to their rapid bounce motion. The theory is valid for moderate electron-temperature, high ion-temperature (auxiliary-heated) plasmas, and as such, is relevant for present and future-generation experimental fusion devices
Nucleation for Lennard-Jones Fluid by Density Functional Theory
Institute of Scientific and Technical Information of China (English)
FU Dong
2005-01-01
@@ A non-mean field density functional theory is employed to investigate the vapour-liquid nucleation. The excess Helmholtz free energy functional is formulated in terms of a local density approximation for short ranged repulsion and a density-gradient expansion for long-ranged attractions. An analytical expression for the direct correlation function of a Lennard-Jones fluid is utilized to take into account the effect of long-ranged attractions on intermolecular correlations. With the predicted bulk properties and surface tension as input, the nucleation properties including density profile, work of formation and number of particles at the reduced temperatures T* = 0.694 and 0.741 are inuestigated. The obtained number of particles in the critical nucleus agrees well with the simulation data.
Particle detachment from fluid interfaces: theory vs. experiments.
Anachkov, Svetoslav E; Lesov, Ivan; Zanini, Michele; Kralchevsky, Peter A; Denkov, Nikolai D; Isa, Lucio
2016-09-28
Microparticle adsorption and self-assembly at fluid interfaces are strongly affected by the particle three-phase contact angle θ. On the single-particle level, θ can be determined by several techniques, including colloidal-probe AFM, the gel-trapping technique (GTT) and the freeze-fracture shadow-casting (FreSCa) method. While GTT and FreSCa provide contact angle distributions measured over many particles, colloidal-probe AFM measures the wettability of an individual (specified) particle attached onto an AFM cantilever. In this paper, we extract θ for smooth microparticles through the analysis of force-distance curves upon particle approach and retraction from the fluid interface. From each retraction curve, we determine: (i) the maximal force, Fmax; (ii) the detachment distance, Dmax; and (iii) the work for quasistatic detachment, W. To relate Fmax, Dmax and W to θ, we developed a detailed theoretical model based on the capillary theory of flotation. The model was validated in three different ways. First, the contact angles, evaluated from Fmax, Dmax and W, are all close in value and were used to calculate the entire force-distance curves upon particle retraction without any adjustable parameters. Second, the model was successfully applied to predict the experimental force-distance curve of a truncated sphere, whose cut is positioned below the point of particle detachment from the interface. Third, our theory was confirmed by the excellent agreement between the particle contact angles obtained from the colloidal-probe AFM data and the ensemble-average contact angles measured by both GTT and FreSCa. Additionally, we devised a very accurate closed-form expression for W (representing the energy barrier for particle detachment), thus extending previous results in the literature.
Modeling of Phase Equilibria Containing Associating Fluids
DEFF Research Database (Denmark)
Derawi, Samer; Kontogeorgis, Georgios
in terms of an activity coefficient model or an equation of state. Our target in this thesis is to review and develop such models capable of describing qualitatively as well as quantitatively phase equilibria in multicomponent multiphase systems containing non-polar, polar, and associating compounds...... equation of state and the association term proposed by Wertheim, typically employed in models like the various variations of SAFT. CPA has been shown in the past to be a successful model for phase equilibria calculations for systems containing water, hydrocarbons and alcohols. In Chapter 4, CPA is applied......In recent years, there has been an increasing interest of the petrochemical industry in modeling of the partitioning of production chemicals e.g. gas hydrate inhibitors, corrosion inhibitors, solvents etc. between the crude oil and water. This requires basically a thermodynamic model either...
Potential theory of adsorption for associating mixtures: possibilities and limitations
DEFF Research Database (Denmark)
Bjørner, Martin Gamel; Shapiro, Alexander; Kontogeorgis, Georgios
2013-01-01
The applicability of the Multicomponent Potential Theory of Adsorption (MPTA) for prediction of the adsorption equilibrium of several associating binary mixtures on different industrial adsorbents is investigated. In the MPTA the adsorbates are considered to be distributed fluids subject to an ex...... of the selectivity are as low as 7-12%. Predictions of the selectivity are generally superior to predictions of the adsorbed amounts. The sensitivity of the model has also been tested, and it is concluded, that predictions are very sensitive to the adsorption energies.......The applicability of the Multicomponent Potential Theory of Adsorption (MPTA) for prediction of the adsorption equilibrium of several associating binary mixtures on different industrial adsorbents is investigated. In the MPTA the adsorbates are considered to be distributed fluids subject...... to describe the solid-fluid interactions. The potential is extended to include adsorbate-absorbent specific capacities rather than an adsorbent specific capacity. Correlations of pure component isotherms are generally excellent with individual capacities, although adsorption on silicas at different...
Dynamic self-consistent field theory for unentangled homopolymer fluids
Mihajlovic, Maja; Lo, Tak Shing; Shnidman, Yitzhak
2005-10-01
We present a lattice formulation of a dynamic self-consistent field (DSCF) theory that is capable of resolving interfacial structure, dynamics, and rheology in inhomogeneous, compressible melts and blends of unentangled homopolymer chains. The joint probability distribution of all the Kuhn segments in the fluid, interacting with adjacent segments and walls, is approximated by a product of one-body probabilities for free segments interacting solely with an external potential field that is determined self-consistently. The effect of flow on ideal chain conformations is modeled with finitely extensible, nonlinearly elastic dumbbells in the Peterlin approximation, and related to stepping probabilities in a random walk. Free segment and stepping probabilities generate statistical weights for chain conformations in a self-consistent field, and determine local volume fractions of chain segments. Flux balance across unit lattice cells yields mean field transport equations for the evolution of free segment probabilities and of momentum densities on the Kuhn length scale. Diffusive and viscous contributions to the fluxes arise from segmental hops modeled as a Markov process, with transition rates reflecting changes in segmental interaction, kinetic energy, and entropic contributions to the free energy under flow. We apply the DSCF equations to study both transient and steady-state interfacial structure, flow, and rheology in a sheared planar channel containing either a one-component melt or a phase-separated, two-component blend.
Stability of EBT of guiding-centre fluid theory
International Nuclear Information System (INIS)
The stability of the hot-electron annulus in the ELMO Bumpy Torus (EBT) is not yet completely understood despite considerable attention. Most stability studies have dealt with localized analysis of simplified models in which the actual magnetic configuration is replaced by a straight-line slab with a gravity to emulate the effects of curvature and gradients in the actual magnetic field. Here, a more realistic geometry, a 'bumpy' cylinder with a 2:1 magnetic mirror ratio, is considered and the response of the hot-electron rings to various non-local perturbations, specifying only the mode number in the ignorable co-ordinate, is examined. Guiding-centre theory (with psub(perpendicular) > psub(parallel)) is used and the second variation in the plasma energy (σW) using a finite-element representation to identify the least stable mode for the plasma is studied. All the equilibria that are examined are found to be unstable for all poloidal mode numbers m>=1, with growth rates increasing with increasing ring beta, plasma beta, and poloidal mode number. It is concluded that two-fluid and/or kinetic effects are required to explain the observed global stability of EBT-I. (author)
Malijevský, Alexandr; Jackson, George; Varga, Szabolcs
2008-10-14
The extension of Onsager's second-virial theory [L. Onsager, Ann. N.Y. Acad. Sci. 51, 627 (1949)] for the orientational ordering of hard rods to mixtures of nonspherical hard bodies with finite length-to-breadth ratios is examined using the decoupling approximations of Parsons [Phys. Rev. A 19, 1225 (1979)] and Lee [J. Chem. Phys. 86, 6567 (1987); 89, 7036 (1988)]. Invariably the extension of the Parsons-Lee (PL) theory to mixtures has in the past involved a van der Waals one-fluid treatment in which the properties of the mixture are approximated by those of a reference one-component hard-sphere fluid with an effective diameter which depends on the composition of the mixture and the molecular parameters of the various components; commonly this is achieved by equating the molecular volumes of the effective hard sphere and of the components in the mixture and is referred to as the PL theory of mixtures. It is well known that a one-fluid treatment is not the most appropriate for the description of the thermodynamic properties of isotropic fluids, and inadequacies are often rectified with a many-fluid (MF) theory. Here, we examine MF theories which are developed from the virial theorem and the virial expansion of the Helmholtz free energy of anisotropic fluid mixtures. The use of the decoupling approximation of the pair distribution function at the level of a multicomponent hard-sphere reference system leads to our MF Parsons (MFP) theory of anisotropic mixtures. Alternatively the mapping of the virial coefficients of the hard-body mixtures onto those of equivalent hard-sphere systems leads to our MF Lee (MFL) theory. The description of the isotropic-nematic phase behavior of binary mixtures of hard Gaussian overlap particles is used to assess the adequacy of the four different theories, namely, the original second-virial theory of Onsager, the usual PL one-fluid theory, and the MF theories based on the Lee (MFL) and Parsons (MFP) approaches. A comparison with the
Malijevský, Alexandr; Jackson, George; Varga, Szabolcs
2008-10-14
The extension of Onsager's second-virial theory [L. Onsager, Ann. N.Y. Acad. Sci. 51, 627 (1949)] for the orientational ordering of hard rods to mixtures of nonspherical hard bodies with finite length-to-breadth ratios is examined using the decoupling approximations of Parsons [Phys. Rev. A 19, 1225 (1979)] and Lee [J. Chem. Phys. 86, 6567 (1987); 89, 7036 (1988)]. Invariably the extension of the Parsons-Lee (PL) theory to mixtures has in the past involved a van der Waals one-fluid treatment in which the properties of the mixture are approximated by those of a reference one-component hard-sphere fluid with an effective diameter which depends on the composition of the mixture and the molecular parameters of the various components; commonly this is achieved by equating the molecular volumes of the effective hard sphere and of the components in the mixture and is referred to as the PL theory of mixtures. It is well known that a one-fluid treatment is not the most appropriate for the description of the thermodynamic properties of isotropic fluids, and inadequacies are often rectified with a many-fluid (MF) theory. Here, we examine MF theories which are developed from the virial theorem and the virial expansion of the Helmholtz free energy of anisotropic fluid mixtures. The use of the decoupling approximation of the pair distribution function at the level of a multicomponent hard-sphere reference system leads to our MF Parsons (MFP) theory of anisotropic mixtures. Alternatively the mapping of the virial coefficients of the hard-body mixtures onto those of equivalent hard-sphere systems leads to our MF Lee (MFL) theory. The description of the isotropic-nematic phase behavior of binary mixtures of hard Gaussian overlap particles is used to assess the adequacy of the four different theories, namely, the original second-virial theory of Onsager, the usual PL one-fluid theory, and the MF theories based on the Lee (MFL) and Parsons (MFP) approaches. A comparison with the
National Athletic Trainers' Association Position Statement: Fluid Replacement for Athletes.
Case, Douglas J.; Armstrong, Lawrence E.; Hillman, Susan K.; Montain, Scott J.; Reiff, Ralph V.; Rich, Brent S. E.; Roberts, William O.; Stone, Jennifer A.
2000-01-01
Presents recommendations from the National Athletic Trainers Association for optimizing the fluid replacement practices of athletes, explaining that dehydration can compromise athletic performance and increase the risk of exertional heat injury. Athletes must be educated about the risks of dehydration and overhydration. They must learn fluid…
Turbulence theories and modelling of fluids and plasmas
International Nuclear Information System (INIS)
Theoretical and heuristic modelling methods are reviewed for studying turbulence phenomena of fluids and plasmas. Emphasis is put on understanding of effects on turbulent characteristics due to inhomogeneities of field and plasma parameters. The similarity and dissimilarity between the methods for fluids and plasmas are sought in order to shed light on the properties that are shared or not by fluid and plasma turbulence. (author)
Turbulence theories and modelling of fluids and plasmas
Energy Technology Data Exchange (ETDEWEB)
Yoshizawa, Akira; Yokoi, Nobumitsu [Institute of Industrial Science, Univ. of Tokyo, Tokyo (Japan); Itoh, Sanae-I. [Research Institute for Applied Mechanics, Kyushu Univ., Kasuga, Fukuoka (Japan); Itoh, Kimitaka [National Inst. for Fusion Science, Toki, Gifu (Japan)
2001-04-01
Theoretical and heuristic modelling methods are reviewed for studying turbulence phenomena of fluids and plasmas. Emphasis is put on understanding of effects on turbulent characteristics due to inhomogeneities of field and plasma parameters. The similarity and dissimilarity between the methods for fluids and plasmas are sought in order to shed light on the properties that are shared or not by fluid and plasma turbulence. (author)
Towards a statistical mechanical theory of active fluids.
Marini Bettolo Marconi, Umberto; Maggi, Claudio
2015-12-01
We present a stochastic description of a model of N mutually interacting active particles in the presence of external fields and characterize its steady state behavior in the absence of currents. To reproduce the effects of the experimentally observed persistence of the trajectories of the active particles we consider a Gaussian force having a non-vanishing correlation time τ, whose finiteness is a measure of the activity of the system. With these ingredients we show that it is possible to develop a statistical mechanical approach similar to the one employed in the study of equilibrium liquids and to obtain the explicit form of the many-particle distribution function by means of the multidimensional unified colored noise approximation. Such a distribution plays a role analogous to the Gibbs distribution in equilibrium statistical mechanics and provides complete information about the microscopic state of the system. From here we develop a method to determine the one- and two-particle distribution functions in the spirit of the Born-Green-Yvon (BGY) equations of equilibrium statistical mechanics. The resulting equations which contain extra-correlations induced by the activity allow us to determine the stationary density profiles in the presence of external fields, the pair correlations and the pressure of active fluids. In the low density regime we obtained the effective pair potential ϕ(r) acting between two isolated particles separated by a distance, r, showing the existence of an effective attraction between them induced by activity. Based on these results, in the second half of the paper we propose a mean field theory as an approach simpler than the BGY hierarchy and use it to derive a van der Waals expression of the equation of state. PMID:26387914
Extended Lubrication Theory: Estimation of Fluid Flow in Channels with Variable Geometry
Tavakol, Behrouz; Froehlicher, Guillaume; Stone, Howard A
2014-01-01
Lubrication theory is broadly applicable to the flow characterization of thin fluid films and the motion of particles near surfaces. We offer an extension to lubrication theory by considering higher-order terms of the analytical approximation to describe the fluid flow in a channel with features of a modest aspect ratio. We find good agreement between our analytical results and numerical simulations. We show that the extended lubrication theory is a robust tool for an accurate estimate of laminar fluid flow in channels with features on the order of the channel height, accounting for both smooth and sharp changes in geometry.
Inclusion of ion orbit loss and intrinsic rotation in plasma fluid rotation theory
International Nuclear Information System (INIS)
The preferential ion orbit loss of counter-current directed ions leaves a predominantly co-current ion distribution in the thermalized ions flowing outward through the plasma edge of tokamak plasmas, constituting a co-current intrinsic rotation. A methodology for representing this essentially kinetic phenomenon in plasma fluid theory is described and combined with a previously developed methodology of treating ion orbit particle and energy losses in fluid theory to provide a complete treatment of ion orbit loss in plasma fluid rotation theory
The variational theory of the perfect dilaton-spin fluid in a Weyl-Cartan space
Babourova, O. V.; Frolov, B. N.
1997-01-01
The variational theory of the perfect fluid with intrinsic spin and dilatonic charge (dilaton-spin fluid) is developed. The spin tensor obeys the classical Frenkel condition. The Lagrangian density of such fluid is stated, and the equations of motion of the fluid, the Weyssenhoff-type evolution equation of the spin tensor and the conservation law of the dilatonic charge are derived. The expressions of the matter currents of the fluid (the canonical energy-momentum 3-form, the metric stress-en...
Complex fluids in biological systems experiment, theory, and computation
2015-01-01
This book serves as an introduction to the continuum mechanics and mathematical modeling of complex fluids in living systems. The form and function of living systems are intimately tied to the nature of surrounding fluid environments, which commonly exhibit nonlinear and history dependent responses to forces and displacements. With ever-increasing capabilities in the visualization and manipulation of biological systems, research on the fundamental phenomena, models, measurements, and analysis of complex fluids has taken a number of exciting directions. In this book, many of the world’s foremost experts explore key topics such as: Macro- and micro-rheological techniques for measuring the material properties of complex biofluids and the subtleties of data interpretation Experimental observations and rheology of complex biological materials, including mucus, cell membranes, the cytoskeleton, and blood The motility of microorganisms in complex fluids and the dynamics of active suspensions Challenges and solut...
A coupled deformation-diffusion theory for fluid-saturated porous solids
Henann, David; Kamrin, Ken; Anand, Lallit
2012-02-01
Fluid-saturated porous materials are important in several familiar applications, such as the response of soils in geomechanics, food processing, pharmaceuticals, and the biomechanics of living bone tissue. An appropriate constitutive theory describing the coupling of the mechanical behavior of the porous solid with the transport of the fluid is a crucial ingredient towards understanding the material behavior in these varied applications. In this work, we formulate and numerically implement in a finite-element framework a large-deformation theory for coupled deformation-diffusion in isotropic, fluid-saturated porous solids. The theory synthesizes the classical Biot theory of linear poroelasticity and the more-recent Coussy theory of poroplasticity in a large deformation framework. In this talk, we highlight several salient features of our theory and discuss representative examples of the application of our numerical simulation capability to problems of consolidation as well as deformation localization in granular materials.
DEFF Research Database (Denmark)
Zuo, You-Xiang; Stenby, Erling Halfdan
1997-01-01
In this research work, the gradient theory (GT) of inhomogeneous fluids was used to calculate interfacial tensions (IFTs). The correlations of the influence parameter are presented for pure hydrocarbons, which can improve the scaling behavior of pure fluids under near-critical conditions....... The overall average absolute deviations (ADDs) of the calculated IFTs from the GT model with the SRK, PR and PT equations of state (EOS´s) for 86 non-polar and weakly polar pure substances are 2.34%, 2.10% and 2.29%, respectively. At low pressure, the lumping method proposed by Leibovici [Leibovici, C.F, 1993....... A consistent procedure for the estimation of properties associated to lumped systems. Fluid Phase Equilibria, 87: 89-197] was used to lump a mixture into one pseudocomponent, and its IFTs were calculated by means of the method of pure fluids. On the basis of the SRK EOS, the overall AAD of mixtures was 3...
Conformally flat static spherically symmetric perfect-fluid distribution in Einstein-Cartan theory
Kalyanshetti, S. B.; Waghmode, B. B.
1983-06-01
We consider the static, conformally flat spherically symmetric perfect-fluid distribution in Einstein-Cartan theory and obtain the field equations. These field equations are solved by adopting Hehl's approach with the assumption that the spins of the particles composing the fluid are all aligned in the radial direction only and the reality conditions are discussed.
Study on Surface Properties for Non-polar Fluids with Density Functional Theory
Institute of Scientific and Technical Information of China (English)
吴畏; 陆九芳; 付东; 刘金晨; 李以圭
2004-01-01
The density functional theory, simplified by the local density approximation and mean-field approximation, is applied to study the surface properties of pure non-polar fluids. A reasonable long rang correction is adopted to avoid the truncation of the potential. The perturbation theory is applied to establish the equation for the phase equilibrium, in which the hard-core chain fluid is as the reference fluid and the Yukawa potential is used as the perturbation term. Three parameters, elk, d and ms, are regressed from the vapor-liquid equilibria, and the surface properties, including density profile, surface tension and local surface tension profile are predicted with these parameters.
Numerical implication of Riemann problem theory for fluid dynamics
International Nuclear Information System (INIS)
The Riemann problem plays an important role in understanding the wave structure of fluid flow. It is also crucial step in some numerical algorithms for accurately and efficiently computing fluid flow; Godunov method, random choice method, and from tracking method. The standard wave structure consists of shock and rarefaction waves. Due to physical effects such as phase transitions, which often are indistinguishable from numerical errors in an equation of state, anomalkous waves may occur, ''rarefaction shocks'', split waves, and composites. The anomalous waves may appear in numerical calculations as waves smeared out by either too much artificial viscosity or insufficient resolution. In addition, the equation of state may lead to instabilities of fluid flow. Since these anomalous effects due to the equation of state occur for the continuum equations, they can be expected to occur for all computational algorithms. The equation of state may be characterized by three dimensionless variables: the adiabatic exponent γ, the Grueneisen coefficient Γ, and the fundamental derivative G. The fluid flow anomalies occur when inequalities relating these variables are violated. 18 refs
Associativity Anomaly in String Field Theory
Bars, Itzhak; Matsuo, Yutaka
2002-01-01
We give a detailed study of the associativity anomaly in open string field theory from the viewpoint of the split string and Moyal formalisms. The origin of the anomaly is reduced to the properties of the special infinite size matrices which relate the conventional open string to the split string variables, and is intimately related to midpoint issues. We discuss two steps to cope with the anomaly. We identify the field subspace that causes the anomaly which is related to the existence of clo...
Kinetic and fluid theory of microwave breakdown in air
International Nuclear Information System (INIS)
We have developed time-dependent fluid and kinetic treatments of electron transport in air in the presence of a propagating microwave pulse. In both cases the HPM pulses are assumed to be of short enough duration so that electron spatial diffusion can be neglected. In addition, we limit our calculations to the non-relativistic regime where effects due to the ponderomotive force are negligible. 6 refs., 4 figs
Gelled propellant flow: Boundary layer theory for power-law fluids in a converging planar channel
Kraynik, Andrew M.; Geller, A. S.; Glick, J. H.
1989-10-01
A boundary layer theory for the flow of power-law fluids in a converging planar channel has been developed. This theory suggests a Reynolds number for such flows, and following numerical integration, a boundary layer thickness. This boundary layer thickness has been used in the generation of a finite element mesh for the finite element code FIDAP. FIDAP was then used to simulate the flow of power-law fluids through a converging channel. Comparison of the analytic and finite element results shows the two to be in very good agreement in regions where entrance and exit effects (not considered in the boundary layer theory) can be neglected.
Computational fluid dynamics in fire engineering theory, modelling and practice
Yuen, Kwok Kit
2009-01-01
Fire and combustion presents a significant engineering challenge to mechanical, civil and dedicated fire engineers, as well as specialists in the process and chemical, safety, buildings and structural fields. We are reminded of the tragic outcomes of 'untenable' fire disasters such as at King's Cross underground station or Switzerland's St Gotthard tunnel. In these and many other cases, computational fluid dynamics (CFD) is at the forefront of active research into unravelling the probable causes of fires and helping to design structures and systems to ensure that they are less likely in the f
Cerebrospinal fluid neopterin and cryopyrin-associated periodic syndrome.
Serrano, Mercedes; Ormazábal, Aida; Antón, Jordi; Aróstegui, Juan I; García-Cazorla, Angels
2009-12-01
Cryopyrin-associated periodic syndrome is a category of autoinflammatory disorders caused by mutations of the NLRP3 gene, with chronic infantile neurologic cutaneous and articular syndrome being the severest clinical phenotype. Various pterins have been reported as mediating immunologic functions in the central nervous system, but to date studies of pterin cerebrospinal fluid (CSF) values and cryopyrin-associated periodic syndrome have been lacking. A 2-year-old child was affected with a severe atypical form of cryopyrin-associated periodic syndrome, suspected based on the analysis of neopterin in CSF. He initially presented isolated neurologic manifestations mimicking a neuroregressive disorder. Blood and CSF analyses did not present any routine inflammatory markers, but CSF neopterin was elevated. Later, the patient developed arthritis and recurrent episodes of fever, and the cryopyrin-associated periodic syndrome diagnosis was confirmed by genetic studies. Neopterin was the most altered indicator over the time. Child neurologists should be on the alert when unexplained neurologic signs appear, giving consideration to the possibility of inflammatory or immune-mediated diseases. The present case demonstrates the clinical utility of measurement of CSF neopterin levels in screening for these immune-mediated diseases, especially when neurologic symptoms are associated with normal results on routine CSF tests.
Bianchi type VI1 cosmological model with wet dark fluid in scale invariant theory of gravitation
Mishra, B
2014-01-01
In this paper, we have investigated Bianchi type VIh, II and III cosmological model with wet dark fluid in scale invariant theory of gravity, where the matter field is in the form of perfect fluid and with a time dependent gauge function (Dirac gauge). A non-singular model for the universe filled with disorder radiation is constructed and some physical behaviors of the model are studied for the feasible VIh (h = 1) space-time.
Mass dependence of shear viscosity in a binary fluid mixture: mode-coupling theory.
Ali, Sk Musharaf; Samanta, Alok; Choudhury, Niharendu; Ghosh, Swapan K
2006-11-01
An expression for the shear viscosity of a binary fluid mixture is derived using mode-coupling theory in order to study the mass dependence. The calculated results on shear viscosity for a binary isotopic Lennard-Jones fluid mixture show good agreement with results from molecular dynamics simulation carried out over a wide range of mass ratio at different composition. Also proposed is a new generalized Stokes-Einstein relation connecting the individual diffusivities to shear viscosity. PMID:17279895
A Thermodynamic Model for Square-well Chain Fluid: Theory and Monte Carlo Simulation
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
A thermodynamic model for the freely jointed square-well chain fluids was developed based on the thermodynamic perturbation theory of Barker-Henderson, Zhang and Wertheim. In this derivation Zhang's expressions for square-well monomers improved from Barker-Henderson compressibility approximation were adopted as the reference fluid, and Wertheim＇s polymerization method was used to obtain the free energy term due to the bond connectivity. An analytic expression for the Helmholtz free energy of the square-well chain fluids was obtained. The expression without adjustable parameters leads to the thermodynamic consistent predictions of the compressibility factors, residual internal energy and constant-volume heat capacity for dimer,4-mer, 8-mer and 16-mer square-well fluids. The results are in good agreement with the Monte Carlo simulation. To obtain the MC data of residual internal energy and the constant-volume heat capacity needed, NVT MC simulations were performed for these square-well chain fluids.
Density Functional Theory Approach for Charged Hard Sphere Fluids Confined in Spherical Micro-Cavity
Institute of Scientific and Technical Information of China (English)
KANG Yan-Shuang; WANG Hai-Jun
2009-01-01
Within the framework of the density functional theory for classical fluids,the equilibrium density profiles of charged hard sphere fluid confined in micro-cavity are studied by means of the modified fundamental measure theory.The dimension of micro-cavity,the charge of hard sphere and the applied electric field are found to have significant effects on the density profiles.In particular,it is shown that Coulomb interaction,excluded volume interaction and applied electric Geld play the central role in controlling the aggregated structure of the system.
DEFF Research Database (Denmark)
Tsivintzelis, Ioannis; Kontogeorgis, Georgios
2012-01-01
The cubic-plus-association (CPA) model is an equation of state (EoS) that combines the Soave–Redlich–Kwong (SRK) equation with the association term from Wertheim’s theory as used in statistical associating fluid theory (SAFT). In the form used here, the CPA EoS does not include separate terms....... The capabilities of the model are illustrated in the first two case studies: the phase behavior of mixtures used in the oxidation of 2-octanol in supercritical CO2 and the investigation of systems containing acetone, methanol, water, chloroform, and methyl acetate. In each case, both correlations of vapor...
On wave propagation characteristics in fluid saturated porous materials by a nonlocal Biot theory
Tong, Lihong; Yu, Yang; Hu, Wentao; Shi, Yufeng; Xu, Changjie
2016-09-01
A nonlocal Biot theory is developed by combing Biot theory and nonlocal elasticity theory for fluid saturated porous material. The nonlocal parameter is introduced as an independent variable for describing wave propagation characteristics in poroelastic material. A physical insight on nonlocal term demonstrates that the nonlocal term is a superposition of two effects, one is inertia force effect generated by fluctuation of porosity and the other is pore size effect inherited from nonlocal constitutive relation. Models for situations of excluding fluid nonlocal effect and including fluid nonlocal effect are proposed. Comparison with experiment confirms that model without fluid nonlocal effect is more reasonable for predicting wave characteristics in saturated porous materials. The negative dispersion is observed theoretically which agrees well with the published experimental data. Both wave velocities and quality factors as functions of frequency and nonlocal parameter are examined in practical cases. A few new physical phenomena such as backward propagation and disappearance of slow wave when exceeding critical frequency and disappearing shear wave in high frequency range, which were not predicted by Biot theory, are demonstrated.
Institute of Scientific and Technical Information of China (English)
李卫华; 诸蔚朝; 马红孺
2003-01-01
One component hard-sphere fluid confined in two planar hard walls is studied by means of density functional theory with Rosenfeld functional and molecular dynamics simulation. The validity of the Rosenfeld functional is examined. Chemical potential, grand potential and free energy as functions of the wall separation are obtained.
Chandre, Cristel; Morrison, Philip; Tassi, Emanuele
2012-01-01
The Hamiltonian structures of the incompressible ideal fluid, including entropy advection, and magnetohydrodynamics are investigated by making use of Dirac's theory of constrained Hamiltonian systems. A Dirac bracket for these systems is constructed by assuming a primary constraint of constant density. The resulting bracket is seen to naturally project onto solenoidal velocity fields.
Yadav, R. B. S.; Prasad, U.
1993-05-01
The nonstatic conformally flat spherically symmetric perfect fluid distribution in Einstein-Cartan theory is considered, and the field equations and their general solution are obtained using Hehl's approach (1974). Particular attention is given to the solution in co-moving coordinates and the explicit expressions for pressure, density, expansion, rotation, and shear and nonzero components of flow vector.
Zhao, HongSheng
2008-01-01
Empirical theories of Dark Matter like MOND gravity and of Dark Energy like f(R) gravity were motivated by astronomical data. But could these theories be branches rooted from a more general hence natural framework? Here we propose the natural Lagrangian of such a framework based on simple dimensional analysis and co-variant symmetry requirements, and explore various outcomes in a top-down fashion. Our framework preserves the co-variant formulation of GR, but allows the expanding physical metric be bent by a single new species of Dark Fluid flowing in space-time. Its non-uniform stress tensor and current vector are simply functions of a vector field of variable norm, resembling the 4-vector electromagnetic potential description for the photon fluid, but is dark (e.g., by very early decoupling from the baryon-radiation fluid). The Dark Fluid framework naturally branches into a continuous spectrum of theories with Dark Energy and Dark Matter effects, including the $f(R)$ gravity, TeVeS-like theories, Einstein-Ae...
Non-Static Plane Symmetric Zeldovich Fluid Model In Scale Invariant Theory
Institute of Scientific and Technical Information of China (English)
B. Mishra
2004-01-01
@@ The perfect fluid distribution in scale invariant theory of gravitation is studied, when the spacetime is described by non-static plane symmetric metric with a time-dependent gauge function. The Zeldovich model of the universe is constructed and some physical properties of the model are discussed.
Comparison of Theories of Anisotropy in Transformer Oil-Based Magnetic Fluids
Directory of Open Access Journals (Sweden)
Jozef Kudelcik
2013-01-01
Full Text Available The external magnetic field in transformer oil-based magnetic fluids leads to the aggregation of magnetic nanoparticles and formation of clusters. These aggregations are the result of the interaction between the external magnetic field and the magnetic moments of the nanoparticles occurs. However, the temperature of magnetic fluids has also very important influence on the structural changes because the mechanism of thermal motion acts against the cluster creation. The acoustic spectroscopy was used to study the anisotropy of transformer oil-based magnetic fluids upon the effect of an external magnetic field and temperature. In present the anisotropy of the magnetic fluids can be described by two theories. Taketomi theory assumes the existence of spherical clusters. These clusters form long chains, aligned in a magnetic field direction. Shliomis in his theory supposed that only nanoparticles formed chains. A comparison of the experimental results with the predictions of the Taketomi theory allowed a determination of the cluster radius and the number density of the colloidal particles. The proportions of the acoustic wave energy used for excitation of the translational and rotational motion were determined.
Gögelein, Christoph; Romano, Flavio; Sciortino, Francesco; Giacometti, Achille
2012-03-01
We study the Kern-Frenkel model for patchy colloids using Barker-Henderson second-order thermodynamic perturbation theory. The model describes a fluid where hard sphere particles are decorated with one patch, so that they interact via a square-well potential if they are sufficiently close one another, and if patches on each particle are properly aligned. Both the gas-liquid and fluid-solid phase coexistences are computed and contrasted against corresponding Monte Carlo simulations results. We find that the perturbation theory describes rather accurately numerical simulations all the way from a fully covered square-well potential down to the Janus limit (half coverage). In the region where numerical data are not available (from Janus to hard-spheres), the method provides estimates of the location of the critical lines that could serve as a guideline for further efficient numerical work at these low coverages. A comparison with other techniques, such as integral equation theory, highlights the important aspect of this methodology in the present context.
Kou, Jisheng
2014-01-01
The gradient theory for the surface tension of simple fluids and mixtures is rigorously analyzed based on mathematical theory. The finite element approximation of surface tension is developed and analyzed, and moreover, an adaptive finite element method based on a physical-based estimator is proposed and it can be coupled efficiently with Newton\\'s method as well. The numerical tests are carried out both to verify the proposed theory and to demonstrate the efficiency of the proposed method. © 2013 Elsevier B.V. All rights reserved.
Bianchi Type VI1 Viscous Fluid Cosmological Model in Wesson´s Theory of Gravitation
Khadekar, G. S.; Avachar, G. R.
2007-03-01
Field equations of a scale invariant theory of gravitation proposed by Wesson [1, 2] are obtained in the presence of viscous fluid with the aid of Bianchi type VIh space-time with the time dependent gauge function (Dirac gauge). It is found that Bianchi type VIh (h = 1) space-time with viscous fluid is feasible in this theory, whereas Bianchi type VIh (h = -1, 0) space-times are not feasible in this theory, even in the presence of viscosity. For the feasible case, by assuming a relation connecting viscosity and metric coefficient, we have obtained a nonsingular-radiating model. We have discussed some physical and kinematical properties of the models.
Dynamic Self-Consistent Field Theory of Inhomogeneous Complex Fluids Under Shear
Mihajlovic, Maja; Lo, Tak Shing; Shnidman, Yitzhak
2003-03-01
Understanding and predicting the interplay between morphology and rheology of sheared, inhomogeneous, complex fluids is of great importance. Yet modeling of such phenomena is in its infancy. We have developed a novel dynamic self-consistent field (DSCF) theory that makes possible detailed computational study of such phenomena. Our DSCF theory couples the time evolution of chain conformation statistics with probabilistic transport equations for volume fractions and momenta, based on local conservation laws formulated on a segmental scale. To generate chain conformation statistics, we are using a modification of the lattice random walk formalism of Scheutjens and Fleer. Their static SCF theory is limited to equilibrium systems, since probability distributions are obtained by free energy minimization, assuming isotropic Gaussian chain conformations. In contrast, our DSCF approach accounts for explicit time evolution of the segmental and (anisotropic) stepping probabilities used for generating chain conformations. We will present highlights of DSCF studies of a variety of inhomogenous fluids containing homopolymers, block copolymers and nanoparticles.
Beyond Poisson-Boltzmann: fluctuations and fluid structure in a self-consistent theory.
Buyukdagli, S; Blossey, R
2016-09-01
Poisson-Boltzmann (PB) theory is the classic approach to soft matter electrostatics and has been applied to numerous physical chemistry and biophysics problems. Its essential limitations are in its neglect of correlation effects and fluid structure. Recently, several theoretical insights have allowed the formulation of approaches that go beyond PB theory in a systematic way. In this topical review, we provide an update on the developments achieved in the self-consistent formulations of correlation-corrected Poisson-Boltzmann theory. We introduce a corresponding system of coupled non-linear equations for both continuum electrostatics with a uniform dielectric constant, and a structured solvent-a dipolar Coulomb fluid-including non-local effects. While the approach is only approximate and also limited to corrections in the so-called weak fluctuation regime, it allows us to include physically relevant effects, as we show for a range of applications of these equations. PMID:27357125
Energy Technology Data Exchange (ETDEWEB)
Kakad, Amar [Research Institute for Sustainable Humanosphere, Kyoto University, Uji, Kyoto 611-0011 (Japan); Indian Institute of Geomagnetism, New Panvel, Navi Mumbai 410-218 (India); Omura, Yoshiharu [Research Institute for Sustainable Humanosphere, Kyoto University, Uji, Kyoto 611-0011 (Japan); Kakad, Bharati [Indian Institute of Geomagnetism, New Panvel, Navi Mumbai 410-218 (India)
2013-06-15
We perform one-dimensional fluid simulation of ion acoustic (IA) solitons propagating parallel to the magnetic field in electron-ion plasmas by assuming a large system length. To model the initial density perturbations (IDP), we employ a KdV soliton type solution. Our simulation demonstrates that the generation mechanism of IA solitons depends on the wavelength of the IDP. The short wavelength IDP evolve into two oppositely propagating identical IA solitons, whereas the long wavelength IDP develop into two indistinguishable chains of multiple IA solitons through a wave breaking process. The wave breaking occurs close to the time when electrostatic energy exceeds half of the kinetic energy of the electron fluid. The wave breaking amplitude and time of its initiation are found to be dependent on characteristics of the IDP. The strength of the IDP controls the number of IA solitons in the solitary chains. The speed, width, and amplitude of IA solitons estimated during their stable propagation in the simulation are in good agreement with the nonlinear fluid theory. This fluid simulation is the first to confirm the validity of the general nonlinear fluid theory, which is widely used in the study of solitary waves in laboratory and space plasmas.
A coupled theory of fluid permeation and large deformations for elastomeric materials
Chester, Shawn A.; Anand, Lallit
2010-11-01
An elastomeric gel is a cross-linked polymer network swollen with a solvent (fluid). A continuum-mechanical theory to describe the various coupled aspects of fluid permeation and large deformations (e.g., swelling and squeezing) of elastomeric gels is formulated. The basic mechanical force balance laws and the balance law for the fluid content are reviewed, and the constitutive theory that we develop is consistent with modern treatments of continuum thermodynamics, and material frame-indifference. In discussing special constitutive equations we limit our attention to isotropic materials, and consider a model for the free energy based on a Flory-Huggins model for the free energy change due to mixing of the fluid with the polymer network, coupled with a non-Gaussian statistical-mechanical model for the change in configurational entropy—a model which accounts for the limited extensibility of polymer chains. As representative examples of application of the theory, we study (a) three-dimensional swelling-equilibrium of an elastomeric gel in an unconstrained, stress-free state; and (b) the following one-dimensional transient problems: (i) free-swelling of a gel; (ii) consolidation of an already swollen gel; and (iii) pressure-difference-driven diffusion of organic solvents across elastomeric membranes.
Density functional theory for molecular orientation of hard rod fluids in hard slits
Institute of Scientific and Technical Information of China (English)
Cao Da-Peng; Cheng Li-Sheng; Wang Wen-Chuan
2007-01-01
A density functional theory (DFT) is used to investigate molecular orientation of hard rod fluids in a hard slit. The DFT approach combines a modified fundamental measure theory (MFMT) for excluded-volume effect with the first order thermodynamics perturbation theory for chain connectivity. In the DFT approach, the intra-molecular bonding orientation function is introduced. We consider the effects of molecular length (i.e. aspect ratio of rod) and packing fraction on the orientations of hard rod fluids and flexible chains. For the flexible chains, the chain length has no significant effect while the packing fraction shows slight effect on the molecular orientation distribution. In contrast, for the hard rod fluids, the chain length determines the molecular orientation distribution, while the packing fraction has no significant effect on the molecular orientation distribution. By making a comparison between molecular orientations of the flexible chain and the hard rod fluid, we find that the molecular stiffness distinctly affects the molecular orientation. In addition, partitioning coefficient indicates that the longer rodlike molecule is more difficult to enter the confined phase, especially at low bulk packing fractions.
Ghobadi, Ahmadreza F.; Elliott, J. Richard
2014-07-01
In this work, a new classical density functional theory is developed for group-contribution equations of state (EOS). Details of implementation are demonstrated for the recently-developed SAFT-γ WCA EOS and selective applications are studied for confined fluids and vapor-liquid interfaces. The acronym WCA (Weeks-Chandler-Andersen) refers to the characterization of the reference part of the third-order thermodynamic perturbation theory applied in formulating the EOS. SAFT-γ refers to the particular form of "statistical associating fluid theory" that is applied to the fused-sphere, heteronuclear, united-atom molecular models of interest. For the monomer term, the modified fundamental measure theory is extended to WCA-spheres. A new chain functional is also introduced for fused and soft heteronuclear chains. The attractive interactions are taken into account by considering the structure of the fluid, thus elevating the theory beyond the mean field approximation. The fluctuations of energy are also included via a non-local third-order perturbation theory. The theory includes resolution of the density profiles of individual groups such as CH2 and CH3 and satisfies stoichiometric constraints for the density profiles. New molecular simulations are conducted to demonstrate the accuracy of each Helmholtz free energy contribution in reproducing the microstructure of inhomogeneous systems at the united-atom level of coarse graining. At each stage, comparisons are made to assess where the present theory stands relative to the current state of the art for studying inhomogeneous fluids. Overall, it is shown that the characteristic features of real molecular fluids are captured both qualitatively and quantitatively. For example, the average pore density deviates ˜2% from simulation data for attractive pentadecane in a 2-nm slit pore. Another example is the surface tension of ethane/heptane mixture, which deviates ˜1% from simulation data while the theory reproduces the excess
Cerebrospinal fluid dynamics in Chiari malformation associated with syringomyelia
Institute of Scientific and Technical Information of China (English)
LIU Bin; WANG Zhen-yu; XIE Jing-cheng; HAN Hong-bin; PEI Xin-long
2007-01-01
Background About 50%-70% of patients with Chiari malformation I (CMI) presented with syringomyelia (SM), which is supposed to be related to abnormal cerebrospinal fluid (CSF) flow around the foramen magnum. The aim of this study was to investigate the cerebrospinal fluid dynamics at levels of the aqueduct and upper cervical spine in patients with CMI associated with SM, and to discuss the possible mechanism of formation of SM.Methods From January to April 2004, we examined 10 adult patients with symptomatic CMI associated with SM and 10 healthy volunteers by phase-contrast MRI. CSF flow patterns were evaluated at seven regions of interest (ROI): the aqueduct and ventral and dorsal subarachnoid spaces of the spine at levels of the cerebellar tonsil, C2-3, and C5-6. The CSF flow waveforms were analyzed by measuring CSF circulation time, durations and maximum velocities of cranial- and caudal-directed flows, and the ratio between the two maximum velocities. Data were analyzed by ttest using SPSS 11.5.Results We found no definite communication between the fourth ventricle and syringomyelia by MRI in the 10 patients.In both the groups, we observed cranial-directed flow of CSF in the early cardiac systolic phase, which changed the direction from cranial to caudal from the middle systolic phase to the early diastolic phase, and then turned back in cranial direction in the late diastolic phase. The CSF flow disappeared at the dorsal ROI at the level of C2-3 in 3 patients and 1 volunteer, and at the level of C5-6 in 6 patients and 3 volunteers. The durations of CSF circulation at all the ROIs were significantly shorter in the patients than those in the healthy volunteers (P=0.014 at the midbrain aqueduct, P=0.019 at the inferior margin of the cerebellar tonsil, P=0.014 at the level of C2-3, and P=0.022 at the level of C5-6). No significant difference existed between the two groups in the initial point and duration of the caudal-directed CSF flow during a cardiac cycle at
Institute of Scientific and Technical Information of China (English)
Sahra Azma; Ghader Rezazadeh; Rasoul Shabani; Elnaz Alizadeh-Haghighi
2016-01-01
Viscous damping is a dominant source of energy dissipation in laterally oscillating micro-structures. In micro-resonators in which the characteristic dimensions are compa-rable to the dimensions of the fluid molecules, the assumption of the continuum fluid theory is no longer justified and the use of micro-polar fluid theory is indispensable. In this paper a mathematical model was presented in order to predict the viscous fluid damping in a laterally oscillating finger of a micro-resonator considering micro-polar fluid theory. The coupled governing partial differential equations of motion for the vibration of the finger and the micro-polar fluid field have been derived. Considering spin and no-spin boundary conditions, the related shape functions for the fluid field were presented. The obtained governing differential equations with time varying boundary conditions have been trans-formed to an enhanced form with homogenous boundary conditions and have been discretized using a Galerkin-based reduced order model. The effects of physical properties of the micro-polar fluid and geometrical parameters of the oscillat-ing structure on the damping ratio of the system have been investigated.
Critical evidence for the prediction error theory in associative learning
Kanta Terao; Yukihisa Matsumoto; Makoto Mizunami
2015-01-01
In associative learning in mammals, it is widely accepted that the discrepancy, or error, between actual and predicted reward determines whether learning occurs. Complete evidence for the prediction error theory, however, has not been obtained in any learning systems: Prediction error theory stems from the finding of a blocking phenomenon, but blocking can also be accounted for by other theories, such as the attentional theory. We demonstrated blocking in classical conditioning in crickets an...
DEFF Research Database (Denmark)
Hjortrup, Peter Buhl; Haase, Nicolai; Wetterslev, Jørn;
2016-01-01
and secondary outcome total fluid input administered from 24 hours before randomisation until the end of day 3 post-randomisation. We performed multivariate analyses with hospital and patient baseline characteristics as covariates to assess associations with fluid volumes given. RESULTS: We included 654......, lower respiratory SOFA subscore and surgery were all independently associated with increased fluid resuscitation volumes. CONCLUSIONS: Hospital characteristics adjusted for patient baseline values were associated with differences in fluid resuscitation volumes given in the first 3 days of severe sepsis......PURPOSE: Fluid resuscitation is a key intervention in patients with sepsis and circulatory impairment. The recommendations for continued fluid therapy in sepsis are vague, which may result in differences in clinical practice. We aimed to evaluate associations between hospital and patient...
Energy Technology Data Exchange (ETDEWEB)
Mirigian, Stephen [University of Illinois, Urbana-Champaign; Schweizer, Kenneth [University of Illinois
2014-01-01
We generalize the force-level nonlinear Langevin equation theory of single particle hopping to include collective effects associated with long range elastic distortion of the liquid. The activated alpha relaxation event is of a mixed spatial character, involving two distinct, but inter-related, local and collective barriers. There are no divergences at volume fractions below jamming or temperatures above zero Kelvin. The ideas are first developed and implemented analytically and numerically in the context of hard sphere fluids. In an intermediate volume fraction crossover regime, the local cage process is dominant in a manner consistent with an apparent Arrhenius behavior. The super-Arrhenius collective barrier is more strongly dependent on volume fraction, dominates the highly viscous regime, and is well described by a nonsingular law below jamming. The increase of the collective barrier is determined by the amplitude of thermal density fluctuations, dynamic shear modulus or transient localization length, and a growing microscopic jump length. Alpha relaxation time calculations are in good agreement with recent experiments and simulations on dense fluids and suspensions of hard spheres. Comparisons of the theory with elastic models and entropy crisis ideas are explored. The present work provides a foundation for constructing a quasi-universal, fit-parameter-free theory for relaxation in thermal molecular liquids over 14 orders of magnitude in time.
Device modeling of superconductor transition edge sensors based on the two-fluid theory
Wang, Tian-Shun; Zhu, Qing-Feng; Wang, Jun-Xian; Li, Tie-Fu; Liu, Jian-She; Chen, Wei; Zhou, Xingxiang
2012-01-01
In order to support the design and study of sophisticated large scale transition edge sensor (TES) circuits, we use basic SPICE elements to develop device models for TESs based on the superfluid-normal fluid theory. In contrast to previous studies, our device model is not limited to small signal simulation, and it relies only on device parameters that have clear physical meaning and can be easily measured. We integrate the device models in design kits based on powerful EDA tools such as CADENCE and OrCAD, and use them for versatile simulations of TES circuits. Comparing our simulation results with published experimental data, we find good agreement which suggests that device models based on the two-fluid theory can be used to predict the behavior of TES circuits reliably and hence they are valuable for assisting the design of sophisticated TES circuits.
Theory and validation of magnetic resonance fluid motion estimation using intensity flow data.
Directory of Open Access Journals (Sweden)
Kelvin Kian Loong Wong
Full Text Available BACKGROUND: Motion tracking based on spatial-temporal radio-frequency signals from the pixel representation of magnetic resonance (MR imaging of a non-stationary fluid is able to provide two dimensional vector field maps. This supports the underlying fundamentals of magnetic resonance fluid motion estimation and generates a new methodology for flow measurement that is based on registration of nuclear signals from moving hydrogen nuclei in fluid. However, there is a need to validate the computational aspect of the approach by using velocity flow field data that we will assume as the true reference information or ground truth. METHODOLOGY/PRINCIPAL FINDINGS: In this study, we create flow vectors based on an ideal analytical vortex, and generate artificial signal-motion image data to verify our computational approach. The analytical and computed flow fields are compared to provide an error estimate of our methodology. The comparison shows that the fluid motion estimation approach using simulated MR data is accurate and robust enough for flow field mapping. To verify our methodology, we have tested the computational configuration on magnetic resonance images of cardiac blood and proved that the theory of magnetic resonance fluid motion estimation can be applicable practically. CONCLUSIONS/SIGNIFICANCE: The results of this work will allow us to progress further in the investigation of fluid motion prediction based on imaging modalities that do not require velocity encoding. This article describes a novel theory of motion estimation based on magnetic resonating blood, which may be directly applied to cardiac flow imaging.
The Aharonov-Bohm effect in a spatially confining theory based on a turbulent fluid
Antonov, Dmitri
2012-01-01
Wilson loops in a turbulent fluid are shown to respect a specific area law corresponding to the Kolmogorov scaling. This law leads to the condensation of a complex-valued scalar field minimally coupled to the velocity field. We use this finding to estimate a v.e.v. of the dual Higgs field, which appears in the hydrodynamic description of a spatially confining dual Landau-Ginzburg theory. The temperature dependence of all other parameters of this theory is found upon a comparison with the spatial string tension and the chromo-magnetic vacuum correlation length of the Yang-Mills gluon plasma. In particular, a nonperturbative contribution to the shear viscosity of the dual fluid comes out exponentially suppressed with temperature. Interactions of the dual Abrikosov vortices with excitations of the fluid yield a long-range Aharonov-Bohm effect. This effect is shown to take place for all but calculated discrete values of the product of the kinematic viscosity of the fluid to the coupling constant of the dual Higgs...
A general theory of non-equilibrium dynamics of lipid-protein fluid membranes
DEFF Research Database (Denmark)
Lomholt, Michael Andersen; Hansen, Per Lyngs; Miao, L.
2005-01-01
We present a general and systematic theory of non-equilibrium dynamics of multi-component fluid membranes, in general, and membranes containing transmembrane proteins, in particular. Developed based on a minimal number of principles of statistical physics and designed to be a meso/macroscopic-sca......-equilibrium phenomena in a range of membrane systems, as discussions in the paper of a few limit cases demonstrate. © EDP Sciences / Società Italiana di Fisica / Springer-Verlag 2005....
Berkeley, Joel
2015-01-01
We explore dualities and solution-generating transformations in various contexts. Our focus is on the T-duality invariant form of supergravity known as double field theory, the $SL(5)$-invariant M-theory extended geometry, and metrics dual under the fluid/gravity correspondence to an incompressible Navier-Stokes fluid. In double field theory (DFT), a wave solution is shown to embed both the F1 string and the pp-wave. For the former, the Goldstone mode dynamics reproduce the duality symmetric string introduced by Tseytlin. We consider solution-generating techniques in DFT in the presence of an isometry, firstly via Buscher-like transformations in the DFT string $\\sigma$-model, and secondly via the DFT equations of motion. In the $SL(5)$-invariant geometry, we provide a chain rule derivation of the covariant equations of motion, and present a wave solution embedding the M2 brane. Lastly, solution-generating transformations for metrics with an isometry are considered in the context of the fluid/gravity correspon...
Energy Technology Data Exchange (ETDEWEB)
Kok Yan Chan, G.; Sclavounos, P. D.; Jonkman, J.; Hayman, G.
2015-04-02
A hydrodynamics computer module was developed for the evaluation of the linear and nonlinear loads on floating wind turbines using a new fluid-impulse formulation for coupling with the FAST program. The recently developed formulation allows the computation of linear and nonlinear loads on floating bodies in the time domain and avoids the computationally intensive evaluation of temporal and nonlinear free-surface problems and efficient methods are derived for its computation. The body instantaneous wetted surface is approximated by a panel mesh and the discretization of the free surface is circumvented by using the Green function. The evaluation of the nonlinear loads is based on explicit expressions derived by the fluid-impulse theory, which can be computed efficiently. Computations are presented of the linear and nonlinear loads on the MIT/NREL tension-leg platform. Comparisons were carried out with frequency-domain linear and second-order methods. Emphasis was placed on modeling accuracy of the magnitude of nonlinear low- and high-frequency wave loads in a sea state. Although fluid-impulse theory is applied to floating wind turbines in this paper, the theory is applicable to other offshore platforms as well.
Metalworking fluid-associated hypersensitivity pneumonitis: a workshop summary.
Kreiss, K; Cox-Ganser, J
1997-10-01
A workshop discussing eight clusters of hypersensitivity pneumonitis in the automotive industry among metalworking fluid-exposed workers concluded that a risk exists for this granulomatous lung disease where water-based fluids are used and unusual microbial contaminants predominate. Strong candidates for microbial etiology are nontuberculous mycobacteria and fungi. Cases of hypersensitivity pneumonitis occur among cases with other work-related respiratory symptoms and chest diseases. Reversibility of disease has occurred in many cases with exposure cessation, allowing return to work to jobs without metalworking fluid exposures or, in some situations, to jobs without the same metalworking fluid exposures. Cases have been recognized with metalworking fluid exposures generally less than 0.5 mg/m3. The workshop participants identified knowledge gaps regarding risk factors, exposure-response relationships, intervention efficacy, and natural history, as well as surveillance needs to define the extent of the problem in this industry. In the absence of answers to these questions, guidance for prevention is necessarily limited.
Hydrogeochemistry of saline fluids and associated water and gas
Martini, Anna Melick
1997-10-01
This dissertation integrates elemental and isotopic analyses of saline formation waters and associated natural gas in sedimentary basins to provide constraints on their origin and geochemical evolution. The Michigan Basin and a modern evaporite environment, the Salina Ometepec, Baja California, were examined as analogs to assess the importance of early versus later diagenetic alteration of minerals and organic matter. The Devonian Antrim Shale, an economic natural gas deposit in the Michigan Basin, produces methane that is dominantly of microbial origin. Microbial methanogenesis was identified by H-isotope analysis of gas and co-produced water. Microbial activity was further established by extremely high deltasp{13}C values for dissolved inorganic carbon (DIC) and for gaseous COsb2. Stable isotopic compositions of Hsb2O, sp3H determinations and sp{14}C dating of DIC in the formation waters, suggest the presence of Pleistocene-age groundwaters, modern groundwaters and basinal brines. Major solutes in formation waters are derived from halite dissolution, clay-mineral cation exchange, and basinal CaClsb2-type brines in subjacent strata. Localized microbial activity within gas productive reservoirs further modify concentrations of COsb2 and CHsb4 gases and dissolved sulfate, acetate and bicarbonate. Chemical heterogeneity of formation waters is even more pronounced from the perspective of the many reservoir rock systems in the basin. Each main aquifer has a distinct suite of chemical properties, which requires not only different solute sources but hydrologic compartmentalization within the basin itself. Formation waters from the Michigan Basin commonly have equimolar concentrations of Casp{2+} and Nasp+. This relation has been observed in many sedimentary basins and has been explained by Nasp+ replacement of Casp{2+}-feldspar. However, Sr isotopic composition and Brsp- concentrations in formation waters from the Michigan Basin coupled with its tectonic setting suggest
Adsorption of short-chain fluids at solid substrates from density functional theory
International Nuclear Information System (INIS)
We use microscopic density functional theory to investigate the adsorption of short-chains at solid surfaces. The fluid is modeled as freely-jointed tangent spheres that interact via a short-ranged attractive potential. Within the framework of fundamental measure theory we study how the structure and surface phase behaviour of adsorbed fluid changes when the chain length is increased. We observe that the wetting temperature rescaled by the bulk critical temperature decreases with an increase of the chain length. For longer chains this temperature reaches a plateau. For the surface critical temperature an inverse effect is observed, i.e. the surface critical temperature increases with the chain length and then attains a plateau. Furthermore, we analyze how the layering transitions change with the change of the chain length and with relative strength of the fluid-solid interaction. The critical temperature of the first layering transition, rescaled by the bulk critical temperature increases slightly with an increase of the chain length. We have found that for longer chains the layering transitions within consecutive layers are shifted towards very low temperatures and that their sequence is finally replaced by a single transition. Finally we investigate capillary condensation of chain fluid in slit-like pores. We find that for a fluid of chains consisting of a larger number of segments we observe an inversion effect. Namely, the critical temperature of capillary condensation decreases with increasing pore width for a certain interval of values of the pore width. This anomalous behavior is also influenced by the interaction between molecules and pore walls. (author)
Theory of activated penetrant diffusion in viscous fluids and colloidal suspensions
Energy Technology Data Exchange (ETDEWEB)
Zhang, Rui; Schweizer, Kenneth S., E-mail: kschweiz@illinois.edu [Department of Materials Science and Frederick Seitz Materials Research Laboratory, University of Illinois, 1304 West Green Street, Urbana, Illinois 61801 (United States)
2015-10-14
We heuristically formulate a microscopic, force level, self-consistent nonlinear Langevin equation theory for activated barrier hopping and non-hydrodynamic diffusion of a hard sphere penetrant in very dense hard sphere fluid matrices. Penetrant dynamics is controlled by a rich competition between force relaxation due to penetrant self-motion and collective matrix structural (alpha) relaxation. In the absence of penetrant-matrix attraction, three activated dynamical regimes are predicted as a function of penetrant-matrix size ratio which are physically distinguished by penetrant jump distance and the nature of matrix motion required to facilitate its hopping. The penetrant diffusion constant decreases the fastest with size ratio for relatively small penetrants where the matrix effectively acts as a vibrating amorphous solid. Increasing penetrant-matrix attraction strength reduces penetrant diffusivity due to physical bonding. For size ratios approaching unity, a distinct dynamical regime emerges associated with strong slaving of penetrant hopping to matrix structural relaxation. A crossover regime at intermediate penetrant-matrix size ratio connects the two limiting behaviors for hard penetrants, but essentially disappears if there are strong attractions with the matrix. Activated penetrant diffusivity decreases strongly with matrix volume fraction in a manner that intensifies as the size ratio increases. We propose and implement a quasi-universal approach for activated diffusion of a rigid atomic/molecular penetrant in a supercooled liquid based on a mapping between the hard sphere system and thermal liquids. Calculations for specific systems agree reasonably well with experiments over a wide range of temperature, covering more than 10 orders of magnitude of variation of the penetrant diffusion constant.
Dense fluid self-diffusion coefficient calculations using perturbation theory and molecular dynamics
Directory of Open Access Journals (Sweden)
COELHO L. A. F.
1999-01-01
Full Text Available A procedure to correlate self-diffusion coefficients in dense fluids by using the perturbation theory (WCA coupled with the smooth-hard-sphere theory is presented and tested against molecular simulations and experimental data. This simple algebraic expression correlates well the self-diffusion coefficients of carbon dioxide, ethane, propane, ethylene, and sulfur hexafluoride. We have also performed canonical ensemble molecular dynamics simulations by using the Hoover-Nosé thermostat and the mean-square displacement formula to compute self-diffusion coefficients for the reference WCA intermolecular potential. The good agreement obtained from both methods, when compared with experimental data, suggests that the smooth-effective-sphere theory is a useful procedure to correlate diffusivity of pure substances.
Beyond Poisson–Boltzmann: fluctuations and fluid structure in a self-consistent theory
Buyukdagli, S.; Blossey, R.
2016-09-01
Poisson–Boltzmann (PB) theory is the classic approach to soft matter electrostatics and has been applied to numerous physical chemistry and biophysics problems. Its essential limitations are in its neglect of correlation effects and fluid structure. Recently, several theoretical insights have allowed the formulation of approaches that go beyond PB theory in a systematic way. In this topical review, we provide an update on the developments achieved in the self-consistent formulations of correlation-corrected Poisson–Boltzmann theory. We introduce a corresponding system of coupled non-linear equations for both continuum electrostatics with a uniform dielectric constant, and a structured solvent—a dipolar Coulomb fluid—including non-local effects. While the approach is only approximate and also limited to corrections in the so-called weak fluctuation regime, it allows us to include physically relevant effects, as we show for a range of applications of these equations.
Towards a theory for vortex filaments in stratified-rotating fluids
Energy Technology Data Exchange (ETDEWEB)
Billant, Paul; Deloncle, Axel; Chomaz, Jean-Marc; Otheguy, Pantxika, E-mail: billant@ladhyx.polytechnique.fr [LadHyX, CNRS, Ecole Polytechnique, F-91128 Palaiseau Cedex (France)
2014-12-01
In inviscid fluids with uniform density, it is common to idealize three-dimensional vortex tubes by filaments (i.e., single lines of an infinitesimal cross section). Thanks to the Kelvin and Helmholtz theorems, it is known that these vortex filaments are transported with the fluid and their circulation is conserved. The induced motions can be computed by the Biot–Savart law, with an appropriate cut off in the integral to avoid singularity. Hence, this approach allows one to model the linear or nonlinear dynamics of vortex flows. A priori, vortex filaments cannot be used in density-stratified and rotating fluids since the circulation is not conserved and the vortex lines are not material lines. However, in this paper we review a theory that is equivalent to vortex filaments. It is based on matched asymptotic expansions for small vortex-core size, weak curvature, and small vortex displacements. The resulting stability equations are formally identical to those of vortex filaments in homogeneous fluids. However, striking differences between homogeneous and stratified-rotating fluids exist, such as the reversal of the self-induced motion for strong stratification or complex self-induction for moderate stratification due to the presence of critical points. The three-dimensional linear stability of vertical vortex pairs and vortex arrays (Karman street, double symmetric row) in stratified and rotating fluids has been investigated using this analytical approach. The results are in very good agreement with the results of direct numerical stability analyses of smooth vortex configurations. Possible extensions to include nonlinear and baroclinic effects are briefly discussed. (paper)
Lu, Jianbo; Xu, Lixin; Tan, Hongyan; Gao, Shanshan
2014-03-01
Varying gravitational constant G(t) (VG) cosmology is studied in this paper, where the modified Friedmann equation and the modified energy conservation equation are given with respect to the constant-G theory. Considering the extended Chaplygin gas (ECG) as background fluid (or thinking that ECG fluid is induced by the variation of G), the unified model of dark matter and dark energy is obtained in VG theory. The parameter spaces are investigated in the VG-ECG model by using the recent cosmic data. Constraint results show β =-G/.HG =-0.003-0.020-0.055+0.021+0.034 for the VG-GCG unified model and β=-0.027-0.032-0.066+0.032+0.059 for the VG-MCG unified model. Equivalently, they correspond to the limits on the current variation of Newton's gravitational constant at 95.4% confidence level |G/.G|today≲4.1×10-12 yr-1 and |G/.G|today≲6.6×10-12 yr-1. And for z ≤3.5, bounds on the variation of G/.G in the VG-ECG unified model are in accordance with the experiment explorations of varying G. In addition, in VG theory the used observational data point still cannot distinguish the VG-GCG and VG-MCG unified model from the most popular ΛCDM cosmology. Furthermore, to see the effects of varying G and physical properties for VG-ECG fluid, we discuss the evolutionary behaviors of cosmological quantities in VG theory, such as G/.G, G./.G and equation of state w, etc. For β <0 a quintom scenario crossing over w=-1 can be realized in the VG-GCG model.
One-dimensional hard rod fluid in a disordered porous medium: scaled particle theory
Directory of Open Access Journals (Sweden)
M. Holovko
2012-06-01
Full Text Available The scaled particle theory is applied to a description of thermodynamic properties of one-dimensional hard rod fluid in disordered porous media. To this end, we extended the SPT2 approach, which had been developed previously. Analytical expressions are obtained for the chemical potential and pressure of a hard-rod fluid in hard rod and overlapping hard rod matrices. A series of new approximations for SPT2 are proposed. It is shown that apart from two well known porosities such as geometrical porosity and specific probe particle porosity, a new type of porosity defined by the maximum value of packing fraction of fluid particles in porous medium should be taken into account. The grand canonical Monte-Carlo simulations are performed to verify the accuracy of the SPT2 approach in combination with the new approximations. It is observed that the theoretical description proposed in this study essentially improves the results up to the highest values of fluid densities.
Mechanical design problems associated with turbopump fluid film bearings
Evces, Charles R.
1990-01-01
Most high speed cryogenic turbopumps for liquid propulsion rocket engines currently use ball or roller contact bearings for rotor support. The operating speeds, loads, clearances, and environments of these pumps combine to make bearing wear a limiting factor on turbopump life. An example is the high pressure oxygen turbopump (HPOTP) used in the Space Shuttle Main Engine (SSME). Although the HPOTP design life is 27,000 seconds at 30,000 rpms, or approximately 50 missions, bearings must currently be replaced after 2 missions. One solution to the bearing wear problem in the HPOTP, as well as in future turbopump designs, is the utilization of fluid film bearings in lieu of continuous contact bearings. Hydrostatic, hydrodynamic, and damping seal bearings are all replacement candidates for contact bearings in rocket engine high speed turbomachinery. These three types of fluid film bearings have different operating characteristics, but they share a common set of mechanical design opportunities and difficulties. Results of research to define some of the mechanical design issues are given. Problems considered include transient strat/stop rub, non-operational rotor support, bearing wear inspection and measurement, and bearing fluid supply route. Emphasis is given to the HPOTP preburner pump (PBP) bearing, but the results are pertinent to high-speed cryogenic turbomachinery in general.
Density functional theory for crystal-liquid interfaces of Lennard-Jones fluid.
Wang, Xin; Mi, Jianguo; Zhong, Chongli
2013-04-28
A density functional approach is presented to describe the crystal-liquid interfaces and crystal nucleations of Lennard-Jones fluid. Within the theoretical framework, the modified fundamental measure theory is applied to describe the free energy functional of hard sphere repulsion, and the weighted density method based on first order mean spherical approximation is used to describe the free energy contribution arising from the attractive interaction. The liquid-solid equilibria, density profiles within crystal cells and at liquid-solid interfaces, interfacial tensions, nucleation free energy barriers, and critical cluster sizes are calculated for face-centered-cubic and body-centered-cubic nucleus. Some results are in good agreement with available simulation data, indicating that the present model is quantitatively reliable in describing nucleation thermodynamics of Lennard-Jones fluid. PMID:23635162
Binary Mixture of Perfect Fluid and Dark Energy in Modified Theory of Gravity
Shaikh, A. Y.
2016-07-01
A self consistent system of Plane Symmetric gravitational field and a binary mixture of perfect fluid and dark energy in a modified theory of gravity are considered. The gravitational field plays crucial role in the formation of soliton-like solutions, i.e., solutions with limited total energy, spin, and charge. The perfect fluid is taken to be the one obeying the usual equation of state, i.e., p = γρ with γ∈ [0, 1] whereas, the dark energy is considered to be either the quintessence like equation of state or Chaplygin gas. The exact solutions to the corresponding field equations are obtained for power-law and exponential volumetric expansion. The geometrical and physical parameters for both the models are studied.
Generalized extended Navier-Stokes theory: Multiscale spin relaxation in molecular fluids
DEFF Research Database (Denmark)
Hansen, Jesper Schmidt
2013-01-01
This paper studies the relaxation of the molecular spin angular velocity in the framework of generalized extended Navier-Stokes theory. Using molecular dynamics simulations, it is shown that for uncharged diatomic molecules the relaxation time decreases with increasing molecular moment of inertia...... per unit mass. In the regime of large moment of inertia the fast relaxation is wave-vector independent and dominated by the coupling between spin and the fluid streaming velocity, whereas for small inertia the relaxation is slow and spin diffusion plays a significant role. The fast wave...... of the coupling in the zero frequency and wave-vector limit is quantified by a characteristic length scale; if the system dimension is comparable to this length the coupling must be included into the fluid dynamical description. It is found that the length scale is independent of moment of inertia but dependent...
Chen, Jiao; Li, Xiaozhong; Bai, Zhenjiang; Fang, Fang; Hua, Jun; Li, Ying; Pan, Jian; Wang, Jian; Feng, Xing; Li, Yanhong
2016-01-01
Objective To evaluate whether early and acquired daily fluid overload (FO), as well as fluctuations in fluid accumulation, were associated with adverse outcomes in critically ill children with severe sepsis. Methods This study enrolled 202 children in a pediatric intensive care unit (PICU) with severe sepsis. Early fluid overload was defined as ≥5% fluid accumulation occurring in the first 24 hours of PICU admission. The maximum daily fluid accumulation ≥5% occurring during the next 6 days in patients with at least 48 hours of PICU stay was defined as PICU-acquired daily fluid overload. The fluctuation in fluid accumulation was calculated as the difference between the maximum and the minimum daily fluid accumulation obtained during the first 7 days after admission. Results Of the 202 patients, 61 (30.2%) died during PICU stay. Among all patients, 41 (20.3%) experienced early fluid overload, including 9 with a FO ≥10%. Among patients with at least 48 hours of PICU stay (n = 154), 36 (23.4%) developed PICU-acquired daily fluid overload, including 2 with a FO ≥10%. Both early fluid overload (AOR = 1.20; 95% CI 1.08–1.33; P = 0.001; n = 202) and PICU-acquired daily fluid overload (AOR = 5.47 per log increase; 95% CI 1.15–25.96; P = 0.032; n = 154) were independent risk factors associated with mortality after adjusting for age, illness severity, etc. However, fluctuations in fluid accumulation were not associated with mortality after adjustment. Length of PICU stay increased with greater fluctuations in fluid accumulation in all patients with at least 48 hours of PICU stay (FO <5%, 5%-10% vs. ≥10%: 4 [3–8], 7 [4–11] vs. 10 [6–16] days; P <0.001; n = 154) and in survivors (4 [3–8], 7 [5–11] vs. 10 [5–15] days; P <0.001; n = 121). Early fluid overload achieved an area under-the-receiver-operating-characteristic curve of 0.74 (95% CI 0.65–0.82; P <0.001; n = 202) for predicting mortality in patients with severe sepsis, with a sensitivity of 67
Quasi-chemical Theory and the Statistical Thermodynamics of the Hard Sphere Fluid
Energy Technology Data Exchange (ETDEWEB)
Pratt, L. R.; Laviolette, Randall Alexander; Gomez, M. A.; Gentile, M.
2001-09-01
We develop a quasi-chemical theory for the study of packing thermodynamics in dense liquids. The situation of hard-core interactions is addressed by considering the binding of solvent molecules to a precisely defined cavity in order to assess the probability that the cavity is entirely evacuated. The primitive quasi-chemical approximation corresponds to an extension of the Poisson distribution used as a default model in an information theory approach. This primitive quasi-chemical theory is in good qualitative agreement with the observations for the hard-sphere fluid of occupancy distributions that are central to quasi-chemical theories but begins to be quantitatively erroneous for the equation of state in the dense liquid regime of d3 > 0.6. How the quasi-chemical approach can be iterated to treat correlation effects is addressed. Consideration of neglected correlation effects leads to a simple model for the form of those contributions neglected by the primitive quasi-chemical approximation. These considerations, supported by simulation observations, identify a "break away" phenomena that requires special thermodynamic consideration for the zero (0) occupancy case as distinct from the rest of the distribution. An empirical treatment leads to a one-parameter model occupancy distribution that accurately fits the hard-sphere equation of state and observed distributions.
Quasi-chemical Theory for the Statistical Thermodynamics of the Hard Sphere Fluid
Pratt, L R; Gómez, M A; Gentile, M E; Pratt, Lawrence R.; Violette, Randall A. La; Gomez, Maria A.; Gentile, Mary E.
2001-01-01
We develop a quasi-chemical theory for the study of packing thermodynamics in dense liquids. The situation of hard-core interactions is addressed by considering the binding of solvent molecules to a precisely defined `cavity' in order to assess the probability that the `cavity' is entirely evacuated. The primitive quasi-chemical approximation corresponds to a extension of the Poisson distribution used as a default model in an information theory approach. This primitive quasi-chemical theory is in good qualitative agreement with the observations for the hard sphere fluid of occupancy distributions that are central to quasi-chemical theories but begins to be quantitatively erroneous for the equation of state in the dense liquid regime of $\\rho d^3>$0.6. How the quasi-chemical approach can be iterated to treat correlation effects is addressed. Consideration of neglected correlation effects leads to a simple model for the form of those contributions neglected by the primitive quasi-chemical approximation. These c...
Zimmermann, Urs; Smallenburg, Frank; Löwen, Hartmut
2016-06-22
Using both dynamical density functional theory and particle-resolved Brownian dynamics simulations, we explore the flow of two-dimensional colloidal solids and fluids driven through a linear channel with a constriction. The flow is generated by a constant external force acting on all colloids. The initial configuration is equilibrated in the absence of flow and then the external force is switched on instantaneously. Upon starting the flow, we observe four different scenarios: a complete blockade, a monotonic decay to a constant particle flux (typical for a fluid), a damped oscillatory behaviour in the particle flux, and a long-lived stop-and-go behaviour in the flow (typical for a solid). The dynamical density functional theory describes all four situations but predicts infinitely long undamped oscillations in the flow which are always damped in the simulations. We attribute the mechanisms of the underlying stop-and-go flow to symmetry conditions on the flowing solid. Our predictions are verifiable in real-space experiments on magnetic colloidal monolayers which are driven through structured microchannels and can be exploited to steer the flow throughput in microfluidics. PMID:27116706
13th Conference of the Canadian Number Theory Association
Alaca, Şaban; Williams, Kenneth
2015-01-01
The theory of numbers continues to occupy a central place in modern mathematics because of both its long history over many centuries as well as its many diverse applications to other fields such as discrete mathematics, cryptography, and coding theory. The proof by Andrew Wiles (with Richard Taylor) of Fermat’s last theorem published in 1995 illustrates the high level of difficulty of problems encountered in number-theoretic research as well as the usefulness of the new ideas arising from its proof. The thirteenth conference of the Canadian Number Theory Association was held at Carleton University, Ottawa, Ontario, Canada from June 16 to 20, 2014. Ninety-nine talks were presented at the conference on the theme of advances in the theory of numbers. Topics of the talks reflected the diversity of current trends and activities in modern number theory. These topics included modular forms, hypergeometric functions, elliptic curves, distribution of prime numbers, diophantine equations, L-functions, Diophantine app...
Reading Educational Reform with Actor Network Theory: Fluid Spaces, Otherings, and Ambivalences
Fenwick, Tara
2011-01-01
In considering two extended examples of educational reform efforts, this discussion traces relations that become visible through analytic approaches associated with actor-network theory (ANT). The strategy here is to present multiple readings of the two examples. The first reading adopts an ANT approach to follow ways that all actors--human and…
Trinh, Khanh Tuoc
2009-01-01
This paper presents a new theory of turbulence in time-independent non-Newtonian fluids. The wall layer is modelled in terms of unsteady exchange of viscous momentum between the wall and the main stream, following the classic visualisation of inrush-sweep-ejection/burst. The thickness of the wall layer is found to be the same for Newtonian and purely viscous non-Newtonian fluids, when normalised with the instantaneous wall parameters at the onset of bursting. The results indicate that the mec...
Dynamic self-consistent field theory of inhomogeneous complex fluids under shear
Mihajlovic, Maja Lazar
Understanding and predicting the interplay between morphology and rheology of sheared, inhomogeneous, complex fluids is of great importance. Yet the modeling of such phenomena is in its infancy. We have developed a novel dynamic self-consistent field (DSCF) theory that makes possible a detailed computational study of such phenomena. Our DSCF theory couples the time evolution of chain conformation statistics with probabilistic transport equations for volume fractions and momenta, based on local conservation laws formulated on a segmental scale. To generate chain conformation statistics, we are using a modification of the lattice random walk formalism of Scheutjens and Fleer. Their static SCF theory is limited to equilibrium systems, since probability distributions are obtained by free energy minimization, assuming isotropic Gaussian chain conformations. In contrast, our DSCF approach accounts for explicit time evolution of the segmental and (anisotropic) conditional stepping probabilities used for generating chain conformations. We have applied the DSCF model to a variety of isothermal inhomogenous fluids containing homopolymers, block copolymers and colloidal particles. In all the simulations, the system is equilibrated before the onset of a steady shear at the walls. Our results suggest that, on short time scales, the velocity evolution resembles shock wave propagation. In the course of time, the amplitude of the shock waves is viscously damped, giving rise to a Couette-like steady state velocity profile. This is also reflected in the temporal evolution of the tensor of the second moment of the end-to-end vector and the dissipative stress tensor. The two- and three-component polymer blends (with a diblock copolymer as the third component) exhibit the interfacial velocity and viscosity slip. The addition of a diblock copolymer suppresses the velocity, and therefore the viscosity slip. Colloidal particles suspended in a simple fluid exhibit layering near the walls
Beatification: Flattening the Poisson Bracket for Two-Dimensional Fluid and Plasma Theories
Viscondi, Thiago F; Morrison, Philip J
2016-01-01
A perturbative method called beatification is presented for a class of two-dimensional fluid and plasma theories. The Hamiltonian systems considered, namely the Euler, Vlasov-Poisson, Hasegawa-Mima, and modified Hasegawa-Mima equations, are naturally described in terms of noncanonical variables. The beatification procedure amounts to finding the correct transformation that removes the explicit variable dependence from a noncanonical Poisson bracket and replaces it with a fixed dependence on a chosen state in phase space. As such, beatification is a major step toward casting the Hamiltonian system in its canonical form, thus enabling or facilitating the use of analytical and numerical techniques that require or favor a representation in terms of canonical, or beatified, Hamiltonian variables.
Indian Academy of Sciences (India)
Amita Wadehra; B M Deb
2007-09-01
A time-dependent generalized non-linear Schrödinger equation (GNLSE) of motion was earlier derived in our laboratory by combining density functional theory and quantum fluid dynamics in threedimensional space. In continuation of the work reported previously, the GNLSE is applied to provide additional knowledge on the femtosecond dynamics of the electron density in the hydrogen molecule interacting with high-intensity laser fields. For this purpose, the GNLSE is solved numerically for many time-steps over a total interaction time of 100 fs, by employing a finite-difference scheme. Various time-dependent (TD) quantities, namely, electron density, ground-state survival probability and dipole moment have been obtained for two laser wavelengths and four different intensities. The high-order harmonics generation (HHG) is also examined. The present approach goes beyond the linear response formalism and, in principle, calculates the TD electron density to all orders of change.
Transmission Characteristics in Tubular Acoustic Metamaterials Studied with Fluid Impedance Theory
Institute of Scientific and Technical Information of China (English)
FAN Li; ZHANG Shu-Yi; ZHANG Hui
2011-01-01
Tubular acoustic metamaterials with negative densities composed of periodical membranes set up along pipes are studied with the fluid impedance theory. In addition to the conventional forbidden bands induced by the Bragg-scattering due to the periodic distributions of different acoustic impedances, the low-frequency forbidden band (LFB) with the low-frequency limit of zero Hertz is studied, in which the LFB is explained with acoustic impedance matching and the Bloch theory. Furthermore, the influences of the structural parameters of the tubular acoustic metamaterials on the transmission characteristics, such as the transmission coefficients, dispersion curves, widths of forbidden and pass bands, fluctuations in pass bands, etc., are evaluated, which can be used in the optimization of the acoustic insulation ability of the metamaterials.%Tubular acoustic metamaterials with negative densities composed of periodical membranes set up along pipes are studied with the fluid impedance theory.In addition to the conventional forbidden bands induced by the Bragg-scattering due to the periodic distributions of different acoustic impedances,the low-frequency forbidden band (LFB) with the low-frequency limit of zero Hertz is studied,in which the LFB is explained with acoustic impedance matching and the Bloch theory.Furthermore,the influences of the structural parameters of the tubular acoustic metamaterials on the transmission characteristics,such as the transmission coefficients,dispersion curves,widths of forbidden and pass bands,fluctuations in pass bands,etc.,are evaluated,which can be used in the optimization of the acoustic insulation ability of the metamaterials.Like electromagnetic metamaterials,acoustic metamaterials have been presented with different structures,which have negative constitutive parameters of acoustic propagation and can realize unique acoustic characteristics and applications.[1-5] Recently,acoustic metamaterials were introduced into acoustic resonance
Generalized extended Navier-Stokes theory: multiscale spin relaxation in molecular fluids.
Hansen, J S
2013-09-01
This paper studies the relaxation of the molecular spin angular velocity in the framework of generalized extended Navier-Stokes theory. Using molecular dynamics simulations, it is shown that for uncharged diatomic molecules the relaxation time decreases with increasing molecular moment of inertia per unit mass. In the regime of large moment of inertia the fast relaxation is wave-vector independent and dominated by the coupling between spin and the fluid streaming velocity, whereas for small inertia the relaxation is slow and spin diffusion plays a significant role. The fast wave-vector-independent relaxation is also observed for highly packed systems. The transverse and longitudinal spin modes have, to a good approximation, identical relaxation, indicating that the longitudinal and transverse spin viscosities have same value. The relaxation is also shown to be isomorphic invariant. Finally, the effect of the coupling in the zero frequency and wave-vector limit is quantified by a characteristic length scale; if the system dimension is comparable to this length the coupling must be included into the fluid dynamical description. It is found that the length scale is independent of moment of inertia but dependent on the state point. PMID:24125208
Unification of Plasma Fluid and Kinetic Theory via Gaussian Radial Basis Functions
Candy, J. M.
2015-11-01
A fundamental macroscopic description of a magnetized plasma is the Vlasov equation supplemented by the nonlinear inverse-square force Fokker-Planck collision operator [Rosenbluth et al., Phys. Rev. 107, 1957]. The Vlasov part describes advection in a six-dimensional phase space whereas the collision operator contains friction and diffusion coefficients that are weighted velocity-space integrals of the particle distribution function. The Fokker-Planck collision operator is an integro-differential, nonlinear (bilinear) operator. Numerical discretization of the operator, in particular for collisions of unlike species, is extremely challenging. In this work, we describe a new approach to discretize the entire kinetic system based on an expansion in Gaussian Radial Basis functions (RBFs). This approach is particularly well-suited to treat the collision operator because the friction and diffusion coefficients can be analytically calculated. Although the RBF method is known to be a powerful scheme for the interpolation of scattered multidimensional data, Gaussian RBFs also have a deep physical interpretation in statistical mechanics and plasma physics as local thermodynamic equilibria. We outline the general theory, highlight the connection to plasma fluid theories, and also give 2D and 3D numerical solutions of the nonlinear Fokker-Planck equation. A broad spectrum of applications for the new method is anticipated in both astrophysical and laboratory plasmas. In particular, we believe that the RBF method may provide a new bridge between fluid and kinetic descriptions of magnetized plasma. Work supported in part by US DOE under DE-FG02-08ER54963.
Fakhrabadi, Mir Masoud Seyyed; Rastgoo, Abbas; Ahmadian, Mohammad Taghi
2013-01-01
The paper presents the effects of fluid flow on the static and dynamic properties of carbon nanotubes that convey a viscous fluid. The mathematical model is based on the modified couple stress theory. The effects of various fluid parameters and boundary conditions on the pull-in voltages are investigated in detail. The applicability of the proposed system as nanovalves or nanosensors in nanoscale fluidic systems is elaborated. The results confirm that the nanoscale system studied in this paper can be properly applied for these purposes.
Institute of Scientific and Technical Information of China (English)
Liu Jian-jun
2003-01-01
During the development of low permeability reservoirs. the interaction between fluid flow and rock-mass deformation is obvious. On the basis of fluid mechanics in porous media and elasto-plastic theory. the author presents an equivalent continuum model to simulate fluid flow in fractured low-permeability oil reservoir coupled with geo-stress. The model not only reflects the porosity change of matrix, but also the permeability change due to the opening and closing of fracture. By analyzing of simulation results, the changes in porosity and permeability and their effect on oil development are studied.
Lutsko, James F.
2007-01-01
A simple model is proposed for the direct correlation function (DCF) for simple fluids consisting of a hard-core contribution, a simple parametrized core correction, and a mean-field tail. The model requires as input only the free energy of the homogeneous fluid, obtained, e.g., from thermodynamic perturbation theory. Comparison to the DCF obtained from simulation of a Lennard-Jones fluid shows this to be a surprisingly good approximation for a wide range of densities. The model is used to co...
Mode-coupling theory of the stress-tensor autocorrelation function of a dense binary fluid mixture
Sinha, Supurna; Marchetti, M. Cristina
2005-01-01
We present a generalized mode-coupling theory for a dense binary fluid mixture. The theory is used to calculate molecular-scale renormalizations to the stress-tensor autocorrelation function (STAF) and to the long-wavelength zero-frequency shear viscosity. As in the case of a dense simple fluid, we find that the STAF appears to decay as $t^{-3/2}$ over an intermediate range of time. The coefficient of this long-time tail is more than two orders of magnitude larger than that obtained from conv...
International Nuclear Information System (INIS)
A statistical mechanical theory that can describe both solids and fluids in a self-consistent way is described. This theory utilizes a optimized reference potential whose repulsive range shrinks with density. A unique feature of the new theory is that solid- and fluid-phase thermodynamic properties are both computed within a single theoretical framework. Hence, it allows us to study melting phenomena in a self-consistent manner. For solids, the new theory treats both harmonic and anharmonic effects in thermodynamic properties on equal footing. Applications to several model and rare gas systems show that the new theory can accurately predict fluid, solid, and fluid-solid transition properties. Effective pair potentials inferred from the analysis of krypton and xenon isotherms contain short- and long-range modifications to the Aziz-Slaman pair potential. The long-range correction is repulsive and originates from the Axilrod-Teller three-body force, while the short-range correction probably originates from many-body forces. Using the computed melting curves of krypton and neon, we discuss the range of validity of the corresponding states principle for rare gas systems. 68 refs., 8 figs., 6 tabs
Duran-Olivencia, Miguel A.; Goddard, Ben; Kalliadasis, Serafim
2015-11-01
Over the last few decades the classical density-functional theory (DFT) and its dynamic extensions (DDFTs) have become a remarkably powerful tool in the study of colloidal fluids. Recently there has been extensive research to generalise all previous DDFTs finally yielding a general DDFT equation (for spherical particles) which takes into account both inertia and hydrodynamic interactions (HI) which strongly influence non-equilibrium properties. The present work will be devoted to a further generalisation of such a framework to systems of anisotropic particles. To this end, the kinetic equation for the Brownian particle distribution function is derived starting from the Liouville equation and making use of Zwanzig's projection-operator techniques. By averaging over all but one particle, a DDFT equation is finally obtained with some similarities to that for spherical colloids. However, there is now an inevitable translational-rotational coupling which affects the diffusivity of asymmetric particles. Lastly, in the overdamped (high friction) limit the theory is notably simplified leading to a DDFT equation which agrees with previous derivations. We acknowledge financial support from European Research Council via Advanced Grant No. 247031.
International Nuclear Information System (INIS)
We have used the density-functional theory to study the effect of varying temperature on the isotropic-nematic transition of a fluid of molecules interacting via the Gay-Berne intermolecular potential. The nematic phase is found to be stable with respect to isotropic phase in the temperature range 0.80≤T*≤1.25. Pair correlation functions needed as input information in density-functional theory is calculated using the Percus-Yevick integral equation theory. We find that the density-functional theory is good for studying the isotropic-nematic transition in molecular fluids if the values of the pair-correlation functions in the isotropic phase are known accurately. We have also compared our results with computer simulation results wherever they are available
Thermodynamically self-consistent theories of fluids interacting through short-range forces.
Caccamo, C; Pellicane, G; Costa, D; Pini, D; Stell, G
1999-11-01
The self-consistent Ornstein-Zernike approximation (SCOZA), the generalized mean spherical approximation (GMSA), the modified hypernetted chain (MHNC) approximation, and the hierarchical reference theory (HRT) are applied to the determination of thermodynamic and structural properties, and the phase diagram of the hard-core Yukawa fluid (HCYF). We investigate different Yukawa-tail screening lengths lambda, ranging from lambda=1.8 (a value appropriate to approximate the shape of the Lennard-Jones potential) to lambda=9 (suitable for a simple one-body modelization of complex fluids like colloidal suspensions and globular protein solutions). The comparison of the results obtained with computer simulation data shows that at relatively low lambda's all the theories are fairly accurate in the prediction of thermodynamic and structural properties; as far as the phase diagram is concerned, the SCOZA and HRT are able to predict the binodal line and the critical parameters in a quantitative manner. At lambda=4 some discrepancies begin to emerge in the performances of the different theoretical approaches: the MHNC remains, on the whole, reasonably accurate in predicting the energy and the contact value of the radial distribution function; the SCOZA predicts well the equation of state up to the highest lambda values investigated. The GMSA and the MHNC underestimate and overestimate, respectively, the liquid coexisting density, while the SCOZA and HRT yield liquid branches that fall between the two former theoretical predictions, although both appear to overestimate the critical temperature somewhat. At higher lambda's the GMSA and MHNC binodals further worsen, while the SCOZA appears to remain usefully predictive. In general, the predictions of all the theories tend to slightly worsen at low temperatures and high density. The determination of the freezing line, performed by means of a one-phase "freezing criterion" (due to other authors) is not particularly satisfactory within
Higher-order weakly nonlinear theory for internal waves in three-layer fluid
Kurkina, O. E.; Kurkin, A. A.; Rouvinskaya, E. A.
2012-04-01
Three-layer stratifications are proved to be a proper approximation of sea water density profile in some basins in the World Ocean with specific hydrological conditions. Some shallow basins such as the Baltic Sea and some river estuaries have more or less continuous three-layer vertical structure caused by the interplay of fresh water discharge to the surface and salt water intrusion in the bottom layers. In order to describe the basic features of the internal wave field in such environments it is necessary to introduce a three-layer model. Such models are considerably more complex than the most popular two-layer systems; however, they represent new dynamical effects and allow for much more analytical progress in their studies compared to the fully stratified situation. In the present study two modes of long internal gravity waves in a three-layer fluid are investigated in the framework of higher-order nonlinear evolutionary equations derived with the use of asymptotic procedure from the governing Euler equations for inviscid incompressible layered medium with "rigid lid" and horizontal impermeable bottom. The equations are written upto the fifth order of the perturbation theory for both interfaces for the waves of both modes: first (fast mode) and second (slow mode, so-called double-humped or varicose). For each equation the coefficients of nonlinearity, dispersion and nonlinear dispersion are expressed explicitly in terms of parameters of this fluid configuration. The behavior and signs of the coefficients are analyzed. The necessary order of the equations is discussed and determined for each case. A few nonlinear asymptotic transformations are proposed to reduce higher-order equations to simpler lower-order or well-known integrable equations (Korteweg - de Vries, Gardner equations). Special attention is paid to the situations when the nonlinear terms of lower orders of perturbation theory can vanish. For such situations particular rescaling is performed in order
Dufal, Simon; Lafitte, Thomas; Haslam, Andrew J.; Galindo, Amparo; Clark, Gary N. I.; Vega, Carlos; Jackson, George
2015-05-01
An accurate representation of molecular association is a vital ingredient of advanced equations of state (EOSs), providing a description of thermodynamic properties of complex fluids where hydrogen bonding plays an important role. The combination of the first-order thermodynamic perturbation theory (TPT1) of Wertheim for associating systems with an accurate description of the structural and thermodynamic properties of the monomer fluid forms the basis of the statistical associating fluid theory (SAFT) family of EOSs. The contribution of association to the free energy in SAFT and related EOSs is very sensitive to the nature of intermolecular potential used to describe the monomers and, crucially, to the accuracy of the representation of the thermodynamic and structural properties. Here we develop an accurate description of the association contribution for use within the recently developed SAFT-VR Mie framework for chain molecules formed from segments interacting through a Mie potential [T. Lafitte, A. Apostolakou, C. Avendaño, A, Galindo, C. S. Adjiman, E. A. Müller, and G. Jackson, J. Chem. Phys. 139, 154504 (2013)]. As the Mie interaction represents a soft-core potential model, a method similar to that adopted for the Lennard-Jones potential [E. A. Müller and K. E. Gubbins, Ind. Eng. Chem. Res. 34, 3662 (1995)] is employed to describe the association contribution to the Helmholtz free energy. The radial distribution function (RDF) of the Mie fluid (which is required for the evaluation of the integral at the heart of the association term) is determined for a broad range of thermodynamic conditions (temperatures and densities) using the reference hyper-netted chain (RHNC) integral-equation theory. The numerical data for the association kernel of Mie fluids with different association geometries are then correlated for a range of thermodynamic states to obtain a general expression for the association contribution which can be applied for varying values of the Mie
[A Case of Spontaneous Cerebrospinal Fluid Leak Associated with Cervical Spondylosis].
Arai, Atsushi; Miyamoto, Hirohito; Shiomi, Ryoji; Tatsumi, Shotaro; Kohmura, Eiji
2016-09-01
Spontaneous cerebrospinal fluid leak and intracranial hypotension associated with cervical spondylosis have rarely been observed, and only a few cases are reported. A 69-year-old woman, previously treated for rectal and thyroid cancer, complained of a non-postural persistent headache. The patient regularly practiced aerobic exercise, but a month earlier she had started experiencing headache and neck pain while exercising. Computed tomography(CT)showed bilateral chronic subdural hematomas, and magnetic resonance imaging(MRI)revealed diffuse dural enhancement and tonsillar herniation. We drained the subdural hematomas and replaced the ventricular reservoir to safely access the cerebrospinal fluid space. After surgery, the persistent headache disappeared for several days, but a postural headache emerged. CT myelogram showed extradural accumulation of the contrast medium at the C2-5 level with cervical spondylosis. The patient was treated with conservative therapy of bed rest and intravenous fluid hydration for two weeks, and the headache improved. CT myelogram after treatment showed no extradural accumulation of the contrast medium. Spontaneous cerebrospinal fluid leak associated with cervical spondylosis could be induced by the repeated minor mechanical stress caused by physical exercise. Therefore, the possibility that non-postural persistent headache may be caused by spontaneous cerebrospinal fluid leak should not be underestimated. PMID:27605479
Hydrocarbon-bearing fluid inclusions in fluorite associated with the Windy Knoll bitumen deposit, UK
Moser, M. R.; Rankin, A. H.; Milledge, H. J.
1992-01-01
Hydrocarbon-bearing fluid inclusions in fluorite, associated with an outcropping bitumen deposit at Windy Knoll, Derbyshire, have been analysed in situ using a combination of microthermometry, Fourier transform infrared (FTIR) microspectrometry, and ultraviolet (UV) microscopy. The inclusions in these samples can be considered as a series with two endmembers: aqueous inclusions containing a low-density vapour phase and inclusions containing liquid "oil" with no detectable aqueous phase. The majority of the inclusions are mixed types containing both aqueous and liquid hydrocarbon phases. Although microthermometry distinguishes at least two different aqueous fluids with varying homogenization temperatures and salinities, the oil fraction is cogenetic and trapped together with just one fluid, a low-salinity, low-calcium brine with an average homogenization temperature of 134°C. The majority of the liquid hydrocarbon-bearing inclusions fluoresce bright blue under UV illumination with peaks around 475 nm, characteristic of paraffinic oils. The FTIR spectra of these inclusions are dominated by peaks assigned to aliphatic C - H bonding. However, inclusions have also been found which display a fluorescence typical of the red-shift associated with less mature oils. The FTIR spectra display peaks assigned to CO, C - O, and O - CH 2 bonding. This study presents new data on the in-situ analysis of hydrocarbon-bearing fluid inclusions from this important area of natural petroleum seepage and ore mineralization. The results suggest a direct link between the fluid inclusion populations, the outcropping bitumens, and fluorite deposition.
Trinh, Khanh Tuoc
2009-01-01
This paper presents a new theory of turbulence in time-independent non-Newtonian fluids. The wall layer is modelled in terms of unsteady exchange of viscous momentum between the wall and the main stream, following the classic visualisation of inrush-sweep-ejection/burst. The thickness of the wall layer is found to be the same for Newtonian and purely viscous non-Newtonian fluids, when normalised with the instantaneous wall parameters at the onset of bursting. The results indicate that the mechanisms of turbulence in Newtonian and time-independent fluids are identical when structural similarity relations in turbulence are based on phase-locked parameters linked with the development of secondary flows rather than on time-averaged wall parameters. This similarity analysis collapses the local critical instantaneous friction factor data of both Newtonian and non-Newtonian fluids at the point of bursting into a single curve. The method greatly simplifies the analysis of turbulent transport phenomena in non-Newtonia...
Bellan, J.; Ohaska, K.
2001-01-01
The objective of this investigation is to derive a set of consistent mixing rules for calculating diffusivities and thermal diffusion factors over a thermodynamic regime encompassing the subcritical and supercritical ranges. These should serve for modeling purposes, and therefore for accurate simulations of high pressure phenomena such as fluid disintegration, turbulent flows and sprays. A particular consequence of this work will be the determination of effective Lewis numbers for supercritical conditions, thus enabling the examination of the relative importance of heat and mass transfer at supercritical pressures.
DEFF Research Database (Denmark)
Kohan, Donald E; Lambers Heerspink, Hiddo J; Coll, Blai;
2015-01-01
) for 12 weeks. Changes in body weight and hemoglobin (Hb) after 2 weeks of treatment were used as surrogate markers of fluid retention. RESULTS: Baseline predictors of weight gain after 2 weeks of atrasentan treatment were higher atrasentan dose, lower eGFR, higher glycated hemoglobin, higher systolic BP....... CONCLUSIONS: In the Reducing Residual Albuminuria in Subjects With Diabetes and Nephropathy With Atrasentan/JAPAN trials, atrasentan-associated fluid retention was more likely in patients with diabetes and nephropathy who had lower eGFR or received a higher dose of atrasentan. Finding that albuminuria...
Fluids density functional theory and initializing molecular dynamics simulations of block copolymers
Brown, Jonathan R.; Seo, Youngmi; Maula, Tiara Ann D.; Hall, Lisa M.
2016-03-01
Classical, fluids density functional theory (fDFT), which can predict the equilibrium density profiles of polymeric systems, and coarse-grained molecular dynamics (MD) simulations, which are often used to show both structure and dynamics of soft materials, can be implemented using very similar bead-based polymer models. We aim to use fDFT and MD in tandem to examine the same system from these two points of view and take advantage of the different features of each methodology. Additionally, the density profiles resulting from fDFT calculations can be used to initialize the MD simulations in a close to equilibrated structure, speeding up the simulations. Here, we show how this method can be applied to study microphase separated states of both typical diblock and tapered diblock copolymers in which there is a region with a gradient in composition placed between the pure blocks. Both methods, applied at constant pressure, predict a decrease in total density as segregation strength or the length of the tapered region is increased. The predictions for the density profiles from fDFT and MD are similar across materials with a wide range of interfacial widths.
Numerical simulation on fault water-inrush based on fluid-solid coupling theory
Institute of Scientific and Technical Information of China (English)
HUANG Han-fu; MAO Xian-biao; YAO Bang-hua; PU Hai
2012-01-01
About 75％ water-inrush accidents in China are caused by geological structure such as faults,therefore,it is necessary to investigate the water-inrush mechanism of faults to provide references for the mining activity above confined water.In this paper,based on the fluid-solid coupling theory,we built the stress-seepage coupling model for rock,then we combined with an example of water-inrush caused by fault,studied the water-inrush mechanism by using the numerical software COMSOL Mutiphysics,analyzed the change rule of shear stress,vertical stress,plastic area and water pressure for stope with a fault,and estimated the water-inrush risk at the different distances between working faces and the fault.The numerical simulation results indicate that:(1) the water-inrush risk will grow as the decrease of the distance between working face and the fault;(2) the failure mode of the rock in floor with fault is shear failure; (3) the rock between water-containing fault and working face failure is the reason for water-inrush.
SDEM modelling of deformation associated with a listric fault system and associated fluid flow
Rasmussen, Marie L.; Clausen, Ole R.; Egholm, David L.; Andresen, Katrine J.
2016-04-01
Numerical modelling of geological structures using FEM, DEM and SDEM methods as well as analogue modelling are widely used in order to achieve a better understanding of the kinematics and dynamics during deformation. The methods are furthermore the ultimate source for mapping (observing) the true geometry of geological structures as well as subsurface fluid flow phenomena in 3D seismic data developed for hydrocarbon exploration. Here we use 3D seismic data and SDEM modelling to suggest a dynamic-kinematic evolution of the deformation in the hangingwall of a listric fault overlying an active salt roller. We use the results to obtain a better understanding of the fluid flow in a complex deformed hangingwall. The case study is focused at the D-1 fault trend in the western part of the Norwegian Danish Basin, at the northern slope of the Ringkøbing-Fyn High. The D-1 main fault detaches along the northern flank of a Zechstein salt roller which was active during the Cenozoic. The seismic analysis shows a system of secondary normal antithetic and synthetic faults dipping approximately 50-60dg within the hangingwall. Shallow gas is trapped in the hangingwall and the secondary faults often confine the accumulations i.e. indicating that the secondary faults are sealing. The modelling confirms that the geometry of the secondary faults is highly controlled by the rheology of different layers in the hangingwall but also on the intensity of the salt movement. The modelling also suggests the presence of vertical deformation zones; structures which are not directly observed on the seismic data. The vertical deformation zones are related to the differential vertical movement of the strata due to salt migration. A neural network trained chimney probability cube shows high probabilities for the presence of minor vertical gas chimneys below the gas accumulations suggesting that vertical fluid migration in the hangingwall occurred in areas with significant vertical salt movements. The
Bellan, Josette; Harstad, Kenneth; Ohsaka, Kenichi
2003-01-01
Although the high pressure multicomponent fluid conservation equations have already been derived and approximately validated for binary mixtures by this PI, the validation of the multicomponent theory is hampered by the lack of existing mixing rules for property calculations. Classical gas dynamics theory can provide property mixing-rules at low pressures exclusively. While thermal conductivity and viscosity high-pressure mixing rules have been documented in the literature, there is no such equivalent for the diffusion coefficients and the thermal diffusion factors. The primary goal of this investigation is to extend the low pressure mixing rule theory to high pressures and validate the new theory with experimental data from levitated single drops. The two properties that will be addressed are the diffusion coefficients and the thermal diffusion factors. To validate/determine the property calculations, ground-based experiments from levitated drops are being conducted.
Institute of Scientific and Technical Information of China (English)
Yi-rang Yuan
2007-01-01
For a coupled system of multiplayer dynamics of fluids in porous media,the characteristic finite element domain decomposition procedures applicable to parallel arithmetic are put forward.Techniques such as calculus of variations,domain decomposition,characteristic method,negative norm estimate,energy method and the theory of prior estimates are adopted.Optimal order estimates in L2 norm are derived for the error in the approximate solution.
Theory of the vortex-clustering transition in a confined two-dimensional quantum fluid
Yu, Xiaoquan; Nian, Jun; Reeves, Matthew T; Bradley, Ashton S
2016-01-01
Clustering of like-sign vortices in a planar bounded domain is known to occur at negative temperature, a phenomenon that Onsager demonstrated to be a consequence of bounded phase space. In a confined superfluid, quantized vortices can support such an ordered phase, provided they evolve as an almost isolated subsystem containing sufficient energy. A detailed theoretical understanding of the statistical mechanics of such states thus requires a microcanonical approach. Here we develop an analytical theory of the vortex clustering transition in a neutral system of quantum vortices confined to a two-dimensional disk geometry, within the microcanonical ensemble. As the system energy increases above a critical value, the system develops global order via the emergence of a macroscopic dipole structure from the homogeneous phase of vortices, spontaneously breaking the Z2 symmetry associated with invariance under vortex circulation exchange, and the rotational SO(2) symmetry due to the disk geometry. The dipole structu...
Theoretical models for fluid thermodynamics based on the quasi-Gaussian entropy theory
Amadei, Andrea
1998-01-01
Summary The theoretical modeling of fluid thermodynamics is one of the most challenging fields in physical chemistry. In fact the fluid behavior, except at very low density conditions, is still extremely difficult to be modeled from a statistical mechanical point of view, as for any realistic model
Absi, Rafik; Dufour, Florence; Huet, Denis; Bennacer, Rachid; Absi, Tahar
2011-01-01
EBI is a further education establishment which provides education in applied industrial biology at level of MSc engineering degree. Fluid mechanics at EBI was considered by students as difficult who seemed somewhat unmotivated. In order to motivate them, we applied a new play-based pedagogy. Students were asked to draw inspiration from everyday life situations to find applications of fluid mechanics and to do experiments to verify and validate some theoretical results obtained in course. In this paper, we present an innovative teaching/learning pedagogy which includes the concept of learning through play and its implications in fluid mechanics for engineering. Examples of atypical experiments in fluid mechanics made by students are presented. Based on teaching evaluation by students, it is possible to know how students feel the course. The effectiveness of this approach to motivate students is presented through an analysis of students' teaching assessment. Learning through play proved a great success in fluid...
Rossitti, Sandro
2013-01-01
Background: Brain arteriovenous malformations (AVMs) produce circulatory and functional disturbances in adjacent as well as in remote areas of the brain, but their physiological effect on the cerebrospinal fluid (CSF) pressure is not well known. Methods: The hypothesis of an intrinsic disease mechanism leading to increased CSF pressure in all patients with brain AVM is outlined, based on a theory of hemodynamic control of intracranial pressure that asserts that CSF pressure is a fraction of the systemic arterial pressure as predicted by a two-resistor series circuit hydraulic model. The resistors are the arteriolar resistance (that is regulated by vasomotor tonus), and the venous resistance (which is mechanically passive as a Starling resistor). This theory is discussed and compared with the knowledge accumulated by now on intravasal pressures and CSF pressure measured in patients with brain AVM. Results: The theory provides a basis for understanding the occurrence of pseudotumor cerebri syndrome in patients with nonhemorrhagic brain AVMs, for the occurrence of local mass effect and brain edema bordering unruptured AVMs, and for the development of hydrocephalus in patients with unruptured AVMs. The theory also contributes to a better appreciation of the pathophysiology of dural arteriovenous fistulas, of vein of Galen aneurismal malformation, and of autoregulation-related disorders in AVM patients. Conclusions: The hydraulic hypothesis provides a comprehensive frame to understand brain AVM hemodynamics and its effect on the CSF dynamics. PMID:23607064
Spyridaki, Eirini C; Simos, Panagiotis; Avgoustinaki, Pavlina D; Dermitzaki, Eirini; Venihaki, Maria; Bardos, Achilles N; Margioris, Andrew N
2014-11-28
Published evidence suggests that obesity impairs cognition. Development of chronic low-grade inflammation (CLGI) represents the earliest consequence of obesity. The present study investigated the association between obesity and fluid intelligence impairment and assessed the potential mediating role of CLGI and psychological (depression/anxiety symptoms), lifestyle (exercise) and physiological (metabolic dysfunction indices) factors in this association. Clinically healthy participants (n 188), grouped as per BMI, underwent cognitive (General Ability Measure for Adults), psychological (Beck Depression Inventory-II and State-Trait Anxiety Inventory) and activity (Godin leisure-time physical activity) measurements. Biochemical parameters included the following: (a) indices of CLGI (high-sensitivity C-reactive protein, erythrocyte sedimentation rate and fibrinogen); (b) insulin resistance (Homeostasis Model Assessment of Insulin Resistance index); (c) adiposity (plasma adiponectin). An inverse association between elevated BMI and fluid intelligence was observed, with obese participants displaying significantly poorer performance compared with age-matched normal-weight peers. Structural equation modelling results were consistent with a negative impact of obesity on cognition that was mediated by CLGI. The results of the present study support the hypothesis that reduced general cognitive ability is associated with obesity, an adverse effect mainly mediated by obesity-associated activation of innate immunity.
Association between fetal weight and amniotic fluid index in women of Central India
Directory of Open Access Journals (Sweden)
Nitin Wadnere
2014-01-01
Full Text Available Background : The placenta is important for fetal growth and well-being. Defective placentation and impaired placental circulation may result in anomalies in fetal growth. Placental volume in the second trimester appears to be closely related to the neonatal weight. The association of body weight with urine output has been observed in human neonates. Our goal is to assess the association of the amniotic fluid index (AFI with the estimated fetal weight (EFW. Materials and Methods : Thirteen hundred and ninety-three pregnant women were prospectively studied by means of an ultrasound over a 12-month period. The fetal weight (FW was estimated using a combination of fetal parameters - bi-parietal diameter, fetal trunk cross-sectional area, and femur length. AFI was assessed using the four quadrant method. The level of statistical significance was set at P ≤ 0.05. Result s: There was no statistically significant association between AFI and EFW (P > 0.05; r = 0.413. We also did not find a significant association between AFI and EFW for all subdivisions of gestation age, except in the 24 - 28 weeks and 29 - 32 weeks′ groups. Conclusion : The FW calculations and amniotic index show a variation in values in late pregnancy. There does not appear to be a linear association between the ultrasound estimate of FW and the amniotic index. The implication of this is that the fetal size need not be taken into cognizance when alterations in amniotic fluid values are noted.
Note on scalars, perfect fluids, constrained field theories, and all that
Diez-Tejedor, Alberto
2013-01-01
The relation of a scalar field with a perfect fluid has generated some debate along the last few years. In this paper we argue that shift-invariant scalar fields can describe accurately the potential flow of an isentropic perfect fluid, but, in general, the identification is possible only for a finite period of time. After that period in the evolution the dynamics of the scalar field and the perfect fluid branch off. The Lagrangian density for the velocity-potential can be read directly from the expression relating the pressure with the Taub charge and the entropy per particle in the fluid, whereas the other quantities of interest can be obtained from the thermodynamic relations.
Theoretical models for fluid thermodynamics based on the quasi-Gaussian entropy theory
Amadei, Andrea
1998-01-01
Summary The theoretical modeling of fluid thermodynamics is one of the most challenging fields in physical chemistry. In fact the fluid behavior, except at very low density conditions, is still extremely difficult to be modeled from a statistical mechanical point of view, as for any realistic model Hamiltonian the configurational part of the partition function cannot be evaluated, i.e., the corresponding high dimensional integral is far too complex to be solved. Hence once a molecular Hamilto...
Theory of errors in Coriolis flowmeter readings due to compressibility of the fluid being metered
Kutin, Jože; Hemp, John
2015-01-01
The compressibility of fluids in a Coriolis mass flowmeter can cause errors in the meter's measurements of density and mass flow rate. These errors may be better described as errors due to the finite speed of sound in the fluid being metered, or due to the finite wavelength of sound at the operating frequency of the meter. In this paper, they are investigated theoretically and calculated to a first approximation (small degree of compressibility). The investigation is limited to straight beam-...
Benschop, Nico F
2009-01-01
""Associative Digital Network Theory"" is intended for researchers at industrial laboratories, teachers and students at technical universities, in electrical engineering, computer science and applied mathematics departments, interested in new developments of modeling and designing digital networks (DN: state machines, sequential and combinational logic) in general, as a combined math/engineering discipline. As background an undergraduate level of modern applied algebra (Birkhoff-Bartee: ""Modern Applied Algebra"" - 1970, and Hartmanis-Stearns: ""Algebraic Structure of Sequential Machines"" - 1
Karunarathne Suneth; Govindapala Dumitha; Udayakumara Yapa; Fernando Harshini
2012-01-01
Abstract Background Cytomegalovirus associated transverse myelitis among immunocompetent adults has been rarely reported. We report a patient presenting with clinical myelitis followed by previously unreported finding of cytomegalovirus deoxyribonucleic acid in cerebrospinal fluid. Case report A forty year old immunocompetent male presented with acute onset progressive bilateral lower limb weakness. His spinal magnetic resonance imaging findings, cerebrospinal fluid analysis and clinical pict...
Munera, Hector A.
2015-08-01
The formal analogy between electromagnetism (EM) and gravitation was noted by Maxwell and Faraday, and later on by Heaviside in the 1890s; the analogy was extensively used in the gravito-magnetism of the 20th century. The connection between EM and fluid theory is explicit in Maxwell’s work, and the equivalence of Maxwell equations (ME) to various wave equations is explained in electrodynamics textbooks (say, Jackson’s) additionally, a little-known paper presented by Henri Malet to the Paris Academy of Sciences (1926), demonstrated that the validity of ME concurrently requires the validity of the vector and the scalar homogeneous wave equations.In the 1990s the present author reported in Foundations of Physics Letters the existence of novel solutions for the homogeneous wave equation in spherical coordinates; it turns out that one class of our solutions (the nonharmonic functions of the first-kind, NHFFK) is equivalent to the unified force of nature proposed around 1760 by Boscovich from philosophical considerations, but without a formal mathematical basis. Our finding is significant because it lends a mathematical foundation to Boscovich’s force, which has extremely interesting properties, as quantization in energy and distance —noted by J. J. Thomson before Bohr’s quantum theory.Associated with spherical surfaces in gravitational equilibrium, the family of even NHFFKs described here predict Titius-Body structures at different scales, as the solar system and the moons of Mars, Jupiter, Uranus, Saturn, and Neptune. Each calculated radius is compared to an average distance of moons/planets: the correlation and the R2 coefficients are quite high. The same NHFFK also predict the existence of ring structures, as those observed in Saturn, and in asteroids belts in our solar system. Newtonian gravity appears as the limit at very large distances from the center of force. The family of odd NHFFK exhibits a non-zero limit as distance tends to infinity, feature that
Hesse, Michael; Birn, Joachim; Schindler, Karl
1990-01-01
A self-consistent two-fluid theory that includes the magnetic field and shear patterns is developed to model stationary electrostatic structures with field-aligned potential drops. Shear flow is also included in the theory since this seems to be a prominent feature of the structures of interest. In addition, Ohmic dissipation, a Hall term, and pressure gradients in a generalized Ohm's law, modified for cases without quasi-neutrality, are included. In the analytic theory, the electrostatic force is balanced by field-aligned pressure gradients (i.e., thermal effects in the direction of the magnetic field) and by pressure gradients and magnetic stresses in the perpendicular direction. Within this theory, simple examples of applications are presented to demonstrate the kind of solutions resulting from the model. The results show how the effects of charge separation and shear in the magnetic field and the velocity can be combined to form self-consistent structures such as are found to exist above the aurora, suggested also in association with solar flares.
Houben, M.L.; Olde Nordkamp, M.J.M.; Nikkels, P.G.J.; van der Ent, C.K.; Meyaard, L.; Bont, L.J.
2013-01-01
The soluble form of the inhibitory immune receptor leukocyte-Associated Ig-like Receptor-1 (sLAIR-1) is present in plasma, urine and synovial fluid and correlates to inflammation. We and others previously showed inflammatory protein expression in normal amniotic fluid at term. We hypothesized that s
LENUS (Irish Health Repository)
O'Daly, Brendan J
2009-06-01
BACKGROUND: Predicting the clinical course in adhesional small bowel obstruction is difficult. There are no validated clinical or radiologic features that allow early identification of patients likely to require surgical intervention. METHODS: We conducted a retrospective review of 100 patients consecutively admitted to a tertiary level teaching hospital over a 3-year period (2002-2004) who had acute adhesional small bowel obstruction and underwent computed tomography (CT). The primary outcomes that we assessed were conservative management or the need for surgical intervention. We investigated time to physiologic gastrointestinal function recovery as a secondary outcome. We examined independent predictors of surgical intervention in a bivariate analysis using a stepwise logistic regression analysis. RESULTS: Of the 100 patients investigated, we excluded 12. Of the 88 remaining patients, 58 (66%) were managed conservatively and 30 (34%) underwent surgery. Peritoneal fluid detected on a CT scan (n = 37) was associated more frequently with surgery than conservative management (46% v. 29%, p = 0.046, chi(2)). Logistical regression identified peritoneal fluid detected on a CT scan as an independent predictor of surgical intervention (odds ratio 3.0, 95% confidence interval 1.15-7.84). CONCLUSION: The presence of peritoneal fluid on a CT scan in patients with adhesional small bowel obstruction is an independent predictor of surgical intervention and should alert the clinician that the patient is 3 times more likely to require surgery.
THEORY AND EXPERIMENT ON THE VISCOUS HEATING OF FLUID DAMPER UNDER SHOCK ENVIRONMENT
Institute of Scientific and Technical Information of China (English)
CHU Deying; ZHANG Zhiyi; WANG Gongxian; HUA Hongxing; WANG Yu
2008-01-01
A specially designed fluid damper used as negative shock pulse generator in the shock resistance test system to dissipate the shock input energy in transient time duration is presented. The theoretical modeling based on the three-dimensional equation of heat transfer through a fluid element is created to predict the viscous heating in the fluid damper under shock conditions. A comprehensive experimental program that investigates the problem of viscous heating in the fluid damper under different shock conditions is conducted on the shock test machine to validate the analytical expression. Temperature histories for the fluid within the damper at two locations, the annular-orifice and the-end-of stroke of the damper, are recorded. The experimental results show that the theoretical model can offer a very dependable prediction for the temperature histories in the damper for increasing input velocity. The theoretical model and experimental data both clearly indicate that the viscous heating in the damper is directly related to the maximum shock velocity input and the pressure between the two sides of the piston head.
Institute of Scientific and Technical Information of China (English)
N. P. Gaikwad; M. S. Borkar; S. S. Charjan
2011-01-01
@@ We investigate the Bianchi type-I massive string magnetized barotropic perfect fluid cosmological model in Rosen's bimetric theory of gravitation with and without a magnetic field by applying the techniques used by Latelier(1979,1980) and Stachel(1983).To obtain a deterministic model of the universe, it is assumed that the universe is filled with barotropic perfect fluid distribution.The physical and geometrical significance of the model are discussed.By comparing our model with the model of Bali et al.(2007), it is realized that there are no big-bang and big-crunch singularities in our model and T＝0 is not the time of the big bang, whereas the model of Bali et al.starts with a big bang at T=0.Further, our model is in agreement with Bali et al.(2007) as time increases in the presence, as well as in the absence, of a magnetic field.
The Alzheimer's Association external quality control program for cerebrospinal fluid biomarkers
DEFF Research Database (Denmark)
Mattsson, Niklas; Andreasson, Ulf; Persson, Staffan;
2011-01-01
The cerebrospinal fluid (CSF) biomarkers amyloid β (Aβ)-42, total-tau (T-tau), and phosphorylated-tau (P-tau) demonstrate good diagnostic accuracy for Alzheimer's disease (AD). However, there are large variations in biomarker measurements between studies, and between and within laboratories....... The Alzheimer's Association has initiated a global quality control program to estimate and monitor variability of measurements, quantify batch-to-batch assay variations, and identify sources of variability. In this article, we present the results from the first two rounds of the program....
Directory of Open Access Journals (Sweden)
Fei Zhu
Full Text Available BACKGROUND: Excessive mechanical loading of articular cartilage producing hydrostatic stress, tensile strain and fluid flow leads to irreversible cartilage erosion and osteoarthritic (OA disease. Since application of high fluid shear to chondrocytes recapitulates some of the earmarks of OA, we aimed to screen the gene expression profiles of shear-activated chondrocytes and assess potential similarities with OA chondrocytes. METHODOLOGY/PRINCIPAL FINDINGS: Using a cDNA microarray technology, we screened the differentially-regulated genes in human T/C-28a2 chondrocytes subjected to high fluid shear (20 dyn/cm(2 for 48 h and 72 h relative to static controls. Confirmation of the expression patterns of select genes was obtained by qRT-PCR. Using significance analysis of microarrays with a 5% false discovery rate, 71 and 60 non-redundant transcripts were identified to be ≥2-fold up-regulated and ≤0.6-fold down-regulated, respectively, in sheared chondrocytes. Published data sets indicate that 42 of these genes, which are related to extracellular matrix/degradation, cell proliferation/differentiation, inflammation and cell survival/death, are differentially-regulated in OA chondrocytes. In view of the pivotal role of cyclooxygenase-2 (COX-2 in the pathogenesis and/or progression of OA in vivo and regulation of shear-induced inflammation and apoptosis in vitro, we identified a collection of genes that are either up- or down-regulated by shear-induced COX-2. COX-2 and L-prostaglandin D synthase (L-PGDS induce reactive oxygen species production, and negatively regulate genes of the histone and cell cycle families, which may play a critical role in chondrocyte death. CONCLUSIONS/SIGNIFICANCE: Prolonged application of high fluid shear stress to chondrocytes recapitulates gene expression profiles associated with osteoarthritis. Our data suggest a potential link between exposure of chondrocytes/cartilage to abnormal mechanical loading and the pathogenesis
Quasi-chemical Theory for the Statistical Thermodynamics of the Hard Sphere Fluid
Pratt, Lawrence R.; LaViolette, Randall A.; Gomez, Maria A.; Gentile, Mary E.
2001-01-01
We develop a quasi-chemical theory for the study of packing thermodynamics in dense liquids. The situation of hard-core interactions is addressed by considering the binding of solvent molecules to a precisely defined `cavity' in order to assess the probability that the `cavity' is entirely evacuated. The primitive quasi-chemical approximation corresponds to a extension of the Poisson distribution used as a default model in an information theory approach. This primitive quasi-chemical theory i...
Diffusion of particles in simple fluids: A joint theory of kinetics and hydrodynamics
Zhao, Hanqing
2016-01-01
The particle diffusion in a fluid is a classical topic that dates back to more than one century ago. However, a full solution to this issue still lacks. In this work the velocity autocorrelation function and the diffusion constant are derived analytically, and the hydrodynamics effect on the particle diffusion is analyzed in detail. Unlike previous studies, the ring-collision effect is exhaustively considered in our treatment, and the hydrodynamics approach is extended to the whole time range. Large scale molecular dynamics simulations for the hard-disk fluid show that our analytical results are valid up to the density close to the crystallization point.
[Research on Wang Mengying's theory of nourishing - Yin and protecting - fluid].
Feng, Chonglian
2002-01-01
As a famous physician of Zhejiang and Jiangsu in the late Qing dynasty, Wang Mengying was especially conversant with Wen Bing (Warm Disease). By reading Wang's works and his 16 - volume clinical case records now extant, it can be held that the clinical career of Wang was penetrated with the idea of nourishing - yin and protecting - fluid, which can be summarized into as. plain nourishing, reducing yang to nourish yin, activating Qi and distributing fluid, and protection prior to having been injured. PMID:12015060
Analytical Thermal Field Theory Applicable to Oil Hydraulic Fluid Film Lubrication
DEFF Research Database (Denmark)
Johansen, Per; Roemer, Daniel Beck; Pedersen, Henrik C.;
2014-01-01
An analytical thermal field theory is derived by a perturbation series expansion solution to the energy conservation equation. The theory is valid for small values of the Brinkman number and the modified Peclet number. This condition is sufficiently satisfied for hydraulic oils, whereby...
DEFF Research Database (Denmark)
Jødal, Lars
The lecture notes describe how body fluid volumes can be measured/estimated using the technique bio-impedance spectroscopy (BIS). The opening chapters assume little or none technical/mathematical knowledge and can hopefully be read by anyone interested in the techneque. Later chapters become more...
An analog fluid model for some tachyonic effects in field theory
Arias, E; Svaiter, N F
2011-01-01
We consider the sound radiation from an acoustic point-like source moving along a supersonic ("space-like") trajectory in a fluid at rest. We call it an acoustic "tachyonic" source. We describe the radiation emitted by this supersonic source. After quantizing the acoustic perturbations, we present the distribution of phonons generated by this classical tachyonic source and the classical wave interference pattern.
Kinetic theory of the eigenmodes of classical fluids and neutron scattering
Cohen, E.G.D.; Schepper, I.M. de; Zuilhof, M.J.
1984-01-01
The lowest lying eigenmodes of a classical fluid have been approximately determined for a wide range of densities and wavenumbers. The most important eigenmodes are direct extensions of the three hydrodynamic heat and sound modes to much larger wavenumbers. A new and consistent interpretation of neu
Institute of Scientific and Technical Information of China (English)
Fu Dong; Liao Tao
2007-01-01
The excess Helmholtz free energy functional for nonpolar chain-like molecules is formulated in terms of a weighted density approximation (WDA) for short-range interactions and a Weaks-Chandler-Andersen (WCA) approximation and a Barker-Henderson (BH) theory for long-range attraction. Within the framework of density functional theory (DFT), vapour-liquid interfacial properties including density profile and surface tension, and vapour-liquid nucleation properties including density profile, work of formation and number of particles are investigated for spherical and chainlike molecules. The obtained vapour-liquid surface tension and the number of particles in critical nucleus for LennardJones (L J) fluids are consistent with the simulation results. The influences of supersaturation, temperature and chain length on vapour-liquid nucleation properties are discussed.
Directory of Open Access Journals (Sweden)
Zhongheng Zhang
2015-02-01
Full Text Available Background and Objective. Acute respiratory distress syndrome (ARDS is characterized by pulmonary edema and may benefit from conservative fluid management. However, conflicting results exist in the literature. The study aimed to investigate the association between mean fluid balance and mortality outcome in ARDS patients who required invasive mechanical ventilation. Methods. The study was a secondary analysis of a prospectively collected dataset obtained from the NHLBI Biologic Specimen and Data Repository Information Coordinating Center. ARDS patients with invasive mechanical ventilation were eligible. Demographic and laboratory data were extracted from the dataset. Multivariable regression model was built by stepwise selection of covariates. A fractional polynomial approach was used to test the linearity of mean fluid balance in the model. The potential interactions of mean fluid balance with other variables were tested. Main Results. A total of 282 patients were eligible for the analysis, including 61 non-survivors with a mortality rate of 21.6%. After stepwise regression analysis, mean fluid balance remained to be an independent predictor of death (OR: 1.00057; 95% CI [1.00034–1.00080]. The two-term model obtained using fractional polynomial analysis was not superior to the linear model. There was significant interaction between mean fluid balance and serum potassium levels (p = 0.011. While the risk of death increased with increasing mean fluid balance at potassium levels of 1.9, 2.9 , 3.9 and 4.9 mmol/l, the risk decreased at potassium level of 5.9 mmol/l. Conclusion. The present study demonstrates that more positive fluid balance in the first 8 days is significantly associated with increased risk of death. However, the relationship between mean fluid balance and mortality can be modified by serum potassium levels. With hyperkalemia, more positive fluid balance is associated with reduced risk of death.
Directory of Open Access Journals (Sweden)
Michiel L Houben
Full Text Available The soluble form of the inhibitory immune receptor leukocyte-Associated Ig-like Receptor-1 (sLAIR-1 is present in plasma, urine and synovial fluid and correlates to inflammation. We and others previously showed inflammatory protein expression in normal amniotic fluid at term. We hypothesized that sLAIR-1 is present in amniotic fluid during term parturition and is related to fetal lung function development. sLAIR-1 was detectable in all amniotic fluid samples (n=355 collected during term spontaneous deliveries. First, potential intra-uterine origins of amniotic fluid sLAIR-1 were explored. Although LAIR-1 was expressed on the surface of amniotic fluid neutrophils, LAIR-1 was not secreted upon ex vivo neutrophil stimulation with LPS, or PMA/ionomycin. Cord blood concentrations of sLAIR-1 were fourfold lower than and not related to amniotic fluid concentrations and placentas showed no or only sporadic LAIR-1 positive cells. Similarly, in post-mortem lung tissue of term neonates that died of non-pulmonary disorders LAIR-1 positive cells were absent or only sporadically present. In fetal urine samples, however, sLAIR-1 levels were even higher than in amniotic fluid and correlated with amniotic fluid sLAIR-1 concentrations. Second, the potential relevance of amniotic fluid sLAIR-1 was studied. sLAIR-1 concentrations had low correlation to amniotic fluid cytokines. We measured neonatal lung function in a convenient subset of 152 infants, using the single occlusion technique, at a median age of 34 days (IQR 30-39. The amniotic fluid concentration of sLAIR-1 was independently correlated to airway compliance (ρ=0.29, P=.001. Taken together, we show the consistent presence of sLAIR-1 in amniotic fluid, which originates from fetal urine. Concentrations of sLAIR-1 in amniotic fluid during term deliveries are independent from levels of other soluble immune mediators. The positive association between concentrations of amniotic fluid sLAIR-1 and neonatal lung
On the estimation of water pure compound parameters in association theories
DEFF Research Database (Denmark)
Grenner, Andreas; Kontogeorgis, Georgios; Michelsen, Michael Locht;
2007-01-01
Determination of the appropriate number of association sites and estimation of parameters for association (SAFT-type) theories is not a trivial matter. Building further on a recently published manuscript by Clark et al., this work investigates aspects of the parameter estimation for water using two...... different association theories. Their performance for various properties as well as against the results presented earlier is demonstrated....
Zhao, H.; Li, B.
2008-01-01
Empirical theories of Dark Matter like MOND gravity and of Dark Energy like f(R) gravity were motivated by astronomical data. But could these theories be branches rooted from a more general hence natural framework? Here we propose the natural Lagrangian of such a framework based on simple dimensional analysis and co-variant symmetry requirements, and explore various outcomes in a top-down fashion. Our framework preserves the co-variant formulation of GR, but allows the expanding physical metr...
Rana, Brinda K.; Stenger, Michael B.; Lee, Stuart M. C.; Macias, Brandon R.; Siamwala, Jamila; Piening, Brian Donald; Hook, Vivian; Ebert, Doug; Patel, Hemal; Smith, Scott; Snyder, Mike; Hargens, Alan R.
2016-01-01
BACKGROUND: Astronauts participating in long duration space missions are at an increased risk of physiological disruptions. The development of visual impairment and intracranial pressure (VIIP) syndrome is one of the leading health concerns for crew members on long-duration space missions; microgravity-induced fluid shifts and chronic elevated cabin CO2 may be contributing factors. By studying physiological and molecular changes in one identical twin during his 1-year ISS mission and his ground-based co-twin, this work extends a current NASA-funded investigation to assess space flight induced "Fluid Shifts" in association with the development of VIIP. This twin study uniquely integrates physiological and -omic signatures to further our understanding of the molecular mechanisms underlying space flight-induced VIIP. We are: (i) conducting longitudinal proteomic assessments of plasma to identify fluid regulation-related molecular pathways altered by long-term space flight; and (ii) integrating physiological and proteomic data with genomic data to understand the genomic mechanism by which these proteomic signatures are regulated. PURPOSE: We are exploring proteomic signatures and genomic mechanisms underlying space flight-induced VIIP symptoms with the future goal of developing early biomarkers to detect and monitor the progression of VIIP. This study is first to employ a male monozygous twin pair to systematically determine the impact of fluid distribution in microgravity, integrating a comprehensive set of structural and functional measures with proteomic, metabolomic and genomic data. This project has a broader impact on Earth-based clinical areas, such as traumatic brain injury-induced elevations of intracranial pressure, hydrocephalus, and glaucoma. HYPOTHESIS: We predict that the space-flown twin will experience a space flight-induced alteration in proteins and peptides related to fluid balance, fluid control and brain injury as compared to his pre-flight protein
M. Valiskó; D. Boda
2005-01-01
A systematic Monte Carlo (MC) simulation and perturbation theoretical (PT) study is reported for the dielectric constant of the polarizable dipolar hard sphere (PDHS) fluid. We take the polarizability of the molecules into account in two different ways. In a continuum approach we place the permanent dipole of the molecule into a sphere of dielectric constant ε∞ in the spirit of Onsager. The high frequency dielectric constant ε∞ is calculated from the Clausius-Mosotti relation, while the diele...
LENUS (Irish Health Repository)
McNally, P
2012-02-01
BACKGROUND: Gastro-oesophageal reflux is common in children with cystic fibrosis (CF) and is thought to be associated with pulmonary aspiration of gastric contents. The measurement of pepsin in bronchoalveolar lavage (BAL) fluid has recently been suggested to be a reliable indicator of aspiration. The prevalence of pulmonary aspiration in a group of children with CF was assessed and its association with lung inflammation investigated. METHODS: This was a cross-sectional case-control study. BAL fluid was collected from individuals with CF (n=31) and healthy controls (n=7). Interleukin-8 (IL-8), pepsin, neutrophil numbers and neutrophil elastase activity levels were measured in all samples. Clinical, microbiological and lung function data were collected from medical notes. RESULTS: The pepsin concentration in BAL fluid was higher in the CF group than in controls (mean (SD) 24.4 (27.4) ng\\/ml vs 4.3 (4.0) ng\\/ml, p=0.03). Those with CF who had raised pepsin concentrations had higher levels of IL-8 in the BAL fluid than those with a concentration comparable to controls (3.7 (2.7) ng\\/ml vs 1.4 (0.9) ng\\/ml, p=0.004). Within the CF group there was a moderate positive correlation between pepsin concentration and IL-8 in BAL fluid (r=0.48, p=0.04). There was no association between BAL fluid pepsin concentrations and age, sex, body mass index z score, forced expiratory volume in 1 s or Pseudomonas aeruginosa colonisation status. CONCLUSIONS: Many children with CF have increased levels of pepsin in the BAL fluid compared with normal controls. Increased pepsin levels were associated with higher IL-8 concentrations in BAL fluid. These data suggest that aspiration of gastric contents occurs in a subset of patients with CF and is associated with more pronounced lung inflammation.
A Rare Case of Spontaneous Pneumocephalus Associated with Nontraumatic Cerebrospinal Fluid Leak
Directory of Open Access Journals (Sweden)
Murad Baba
2016-01-01
Full Text Available Introduction. Spontaneous nontraumatic pneumocephalus (PNC and cerebrospinal fluid (CSF leaks are both very uncommon conditions. We report a rare case of spontaneous pneumocephalus associated with CSF leak secondary to right sphenoid sinus bony defect without history of trauma. Case Description. 51-year-old Hispanic female with past medical history of hypertension and idiopathic intracranial hypertension (Pseudotumor Cerebri presented to the emergency room complaining of headache and clear discharge from the right nostril. Physical examination was significant for right frontal sinus tenderness and clear discharge from right nostril. Computed Tomography (CT scan of the brain showed moderate amount of extra-axial air within the right cerebral hemisphere indicative of pneumocephalus. CT scan of facial bones showed bony defect along the right sphenoid sinus with abnormal CSF collection. The patient was started on intravenous antibiotics for meningitis prophylaxis and subsequently underwent transsphenoidal repair of cerebrospinal fluid leak with abdominal fat graft. CSF rhinorrhea stopped completely after the surgery with near complete resolution of pneumocephalus before discharge. Conclusions. Early identification of pneumocephalus and surgical intervention can help decrease the morbidity and avoid possible complications. Idiopathic intracranial hypertension, although rare, can lead to CSF leak and pneumocepahlus.
Portillo, María Eugenia; Salvadó, Margarita; Trampuz, Andrej; Siverio, Ana; Alier, Albert; Sorli, Lluisa; Martínez, Santos; Pérez-Prieto, Daniel; Horcajada, Juan P.; Puig-Verdie, Lluis
2015-01-01
Sonication improved the diagnosis of orthopedic implant-associated infections (OIAI). We investigated the diagnostic performance of sonication fluid inoculated into blood culture bottles in comparison with that of intraoperative tissue and sonication fluid cultures. Consecutive patients with removed orthopedic hardware were prospectively included and classified as having OIAI or aseptic failure (AF) according to standardized criteria. The diagnostic procedure included the collection of five i...
Portillo, Mar??a Eugenia; Salvad??, Margarita; Trampuz, Andrej; Siverio, Ana; Alier, Albert; Sorli Red??, M. Luisa; Mart??nez, Santos; P??rez, Daniel; Horcajada Gallego, Juan Pablo; Puig Verdi??, Lu??s
2015-01-01
Sonication improved the diagnosis of orthopedic implant-associated infections (OIAI). We investigated the diagnostic performance of sonication fluid inoculated into blood culture bottles in comparison with that of intraoperative tissue and sonication fluid cultures. Consecutive patients with removed orthopedic hardware were prospectively included and classified as having OIAI or aseptic failure (AF) according to standardized criteria. The diagnostic procedure included the collection of five i...
2010-10-01
... 46 Shipping 2 2010-10-01 2010-10-01 false Main and auxiliary machinery and associated equipment... SECURITY (CONTINUED) MARINE ENGINEERING PERIODIC TESTS AND INSPECTIONS Periodic Tests of Machinery and Equipment § 61.20-3 Main and auxiliary machinery and associated equipment, including fluid control...
Mathematical Models of Fluid Dynamics Modeling, Theory, Basic Numerical Facts An Introduction
Ansorge, Rainer
2009-01-01
Without sacrificing scientific strictness, this introduction to the field guides readers through mathematical modeling, the theoretical treatment of the underlying physical laws and the construction and effective use of numerical procedures to describe the behavior of the dynamics of physical flow. The book is carefully divided into three main parts:. - The design of mathematical models of physical fluid flow;. - A theoretical treatment of the equations representing the model, as Navier-Stokes, Euler, and boundary layer equations, models of turbulence, in order to gain qualitative as well as q
Directory of Open Access Journals (Sweden)
Alborizi Abdolvahab
2009-06-01
Full Text Available We describe the development of enterovirus meningoencephalitis associated with increased adenosine deaminase in cerebrospinal fluid of a 12-year-old boy, a known case of hypogamaglobulinemia despite monthly replacement of IVIg.The patient was referred to our center with fever, headache and vomiting for 10 days. CSF analysis was compatible with aseptic meningoencephalitis but high CSF protein (>200mg/dl and high level of adenosine deaminase in CSF (30IU/L were against the diagnosis of simple viral meningoencephalitis. Nested PCR of CSF for entrovirus was positive. Treatment with daily high-dose IVIg was commenced, with significant clinical improvement. For patients with increased ADA and lymphocytic pleocytosis in CSF, differential diagnoses should include enteroviral meningitis. Antibodies, although crucial, cannot on their own prevent enteroviral infection in some hypogamaglbulinemic patients.
Yu, Yang-Xin
2009-07-14
A novel weighted density functional theory (WDFT) for an inhomogeneous 12-6 Lennard-Jones fluid is proposed based on the modified fundamental measure theory for repulsive contribution, the mean-field approximation for attractive contribution, and the first-order mean-spherical approximation with a weighted density for correlation contribution. Extensive comparisons of the theoretical results with molecular simulation and experimental data indicate that the new WDFT yields accurate density profiles, adsorption isotherms, fluid-solid interfacial tensions, as well as disjoining potentials and pressures of simple gases such as argon, nitrogen, methane, ethane, and neon confined in slitlike pores or near graphitic solid surfaces. The present WDFT performs better than the nonlocal density functional theory, which is frequently used in the study of adsorption on porous materials. Since the proposed theory possesses a good dimensional crossover and is able to correctly reduce to two-dimensional case, it performs very well even in very narrow pores. In addition, the present WDFT reproduces very well the supercritical fluid-solid interfacial tensions, whereas the theory of Sweatman underestimates them at high bulk densities. The present WDFT predicts that the increase in the fluid-wall attraction may change the sign of the interfacial tension and hence may make the wall from "phobic" to "philic" with respect to the fluid. The new WDFT is computationally as simple and efficient as the mean-field theory and avoids the second-order direct correlation function as an input. It provides a universal way to construct the excess Helmholtz free-energy functional for inhomogeneous fluids such as Yukawa, square-well, and Sutherland fluids.
Hengartner, Michael P; Ajdacic-Gross, Vladeta; Rodgers, Stephanie; Müller, Mario; Haker, Helene; Rössler, Wulf
2014-08-01
There is some evidence that fluid intelligence as well as empathy may be significantly related to personality disorders (PDs). To our knowledge, no study has addressed those issues simultaneously in all 10 DSM PDs in a sample of the general population. We analysed data from 196 participants aged 20–41 from the Epidemiology Survey of the Zurich Programme for Sustainable Development of Mental Health Services (ZInEP), a comprehensive psychiatric survey in the general population of Zurich, Switzerland. We assessed the digit symbol-coding test (DSCT), the “reading the mind in the eyes” test (RMET) and the interpersonal reactivity index (IRI). Both measures of cognitive empathy (i.e. RMET and IRI perspective taking) were not related to any PD trait-score. The total PD trait-score was significantly associated with low scores on DSCT and IRI empathic concern and high scores on IRI personal distress, which indicates a dose–response relationship in those measures. DSCT was particularly related to borderline PD, IRI empathic concern to schizoid and narcissistic PDs, and IRI personal distress to avoidant PD. The proportion of variance explained in the total PD trait-score accounted for by DSCT, IRI empathic concern and IRI personal distress was 2.6, 2.3 and 13.3 %, respectively. Symptomatology and severity of PDs are related to low fluid intelligence and reduced emotional empathy as characterized by low empathic concern and high personal distress towards emotional expressions of others. Further research is needed that examines the association between cognitive empathy and personality pathology as well as potential clinical applications. PMID:24022591
Hengartner, Michael P; Ajdacic-Gross, Vladeta; Rodgers, Stephanie; Müller, Mario; Haker, Helene; Rössler, Wulf
2014-08-01
There is some evidence that fluid intelligence as well as empathy may be significantly related to personality disorders (PDs). To our knowledge, no study has addressed those issues simultaneously in all 10 DSM PDs in a sample of the general population. We analysed data from 196 participants aged 20–41 from the Epidemiology Survey of the Zurich Programme for Sustainable Development of Mental Health Services (ZInEP), a comprehensive psychiatric survey in the general population of Zurich, Switzerland. We assessed the digit symbol-coding test (DSCT), the “reading the mind in the eyes” test (RMET) and the interpersonal reactivity index (IRI). Both measures of cognitive empathy (i.e. RMET and IRI perspective taking) were not related to any PD trait-score. The total PD trait-score was significantly associated with low scores on DSCT and IRI empathic concern and high scores on IRI personal distress, which indicates a dose–response relationship in those measures. DSCT was particularly related to borderline PD, IRI empathic concern to schizoid and narcissistic PDs, and IRI personal distress to avoidant PD. The proportion of variance explained in the total PD trait-score accounted for by DSCT, IRI empathic concern and IRI personal distress was 2.6, 2.3 and 13.3 %, respectively. Symptomatology and severity of PDs are related to low fluid intelligence and reduced emotional empathy as characterized by low empathic concern and high personal distress towards emotional expressions of others. Further research is needed that examines the association between cognitive empathy and personality pathology as well as potential clinical applications.
DEFF Research Database (Denmark)
Ristinmaa, M.; Ottosen, N.S.; Johannesson, Björn
2011-01-01
and the formulation applies to general anisotropy and the existence of residual stresses. Generalized forms of Fourier's, Fick's and Darcy's laws are derived and also the stresses on the constituent, phase and mixture level are established; in addition, the evolution law for general plasticity is given. Finally....... Equilibrium curves for absorption and desorption also emerge from the theory....
Understanding the fluid nature of personhood - the ring theory of personhood.
Radha Krishna, Lalit Kumar; Alsuwaigh, Rayan
2015-03-01
Familial determination, replete with its frequent usurping of patient autonomy, propagation of collusion, and circumnavigation of direct patient involvement in their own care deliberations, continues to impact clinical practice in many Asian nations. Suggestions that underpinning this practice, in Confucian-inspired societies, is the adherence of the populace to the familial centric ideas of personhood espoused by Confucian ethics, provide a novel means of understanding and improving patient-centred care at the end of life. Clinical experience in Confucian-inspired Singapore, however, suggests that personhood is conceived in broader terms. This diverging view inspired a study of local conceptions of personhood and scrutiny of the influence of the family upon it. From the data gathered, a culturally appropriate, clinically relevant and ethically sensitive concept of personhood was proposed: the Ring Theory of Personhood (Ring Theory) that better captures the nuances of local conceptions of personhood. The Ring Theory highlights the fact that, far from being solely dependent upon familial centric ideals, local conceptions of personhood are dynamic, context dependent, evolving ideas delineated by four dimensions. Using the Ring Theory, the nature of familial influences upon the four dimensions of personhood - the Innate, Individual, Relational and Societal - are examined to reveal that, contrary to perceived knowledge, conceptions of personhood within Confucian societies are not the prime reason for the continued presence of this decision-making model but remain present within local thinking and practices as a sociocultural residue and primarily because of inertia in updating ideas. PMID:24547934
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M.Valiskó
2005-01-01
Full Text Available A systematic Monte Carlo (MC simulation and perturbation theoretical (PT study is reported for the dielectric constant of the polarizable dipolar hard sphere (PDHS fluid. We take the polarizability of the molecules into account in two different ways. In a continuum approach we place the permanent dipole of the molecule into a sphere of dielectric constant ε∞ in the spirit of Onsager. The high frequency dielectric constant ε∞ is calculated from the Clausius-Mosotti relation, while the dielectric constant of the polarizable fluid is obtained from the Kirkwood-Fröhlich equation. In the molecular approach, the polarizability is built into the model on the molecular level, which makes the interactions non-pairwise additive. Here we use Wertheim's renormalized PT method to calculate the induced dipole moment, while the dielectric constant is calculated from our recently introduced formula. We also apply a series expansion for the dielectric constant both in the continuum and the molecular approach. These series expansions ensure a better agreement with simulation results. The agreement between our MC data and the PT results in the molecular approach is excellent for low to moderate dipole moments and polarizabilities. At stronger dipolar interactions ergodicity problems and anizotropic behaviour appear where simulation results become uncertain and the theoretical approach becomes invalid.
Starks, Erika J.; O'Grady, J. Patrick; Hoscheidt, Siobhan M.; Racine, Annie M.; Carlsson, Cindy M.; Zetterberg, Henrik; Blennow, Kaj; Okonkwo, Ozioma C.; Puglielli, Luigi; Asthana, Sanjay; Dowling, N. Maritza; Gleason, Carey E.; Anderson, Rozalyn M.; Davenport-Sis, Nancy J.; DeRungs, LeAnn M.; Sager, Mark A.; Johnson, Sterling C.; Bendlin, Barbara B.
2015-01-01
Background Insulin resistance (IR) is linked with the occurrence of pathological features observed in Alzheimer's disease (AD), including neurofibrillary tangles and amyloid plaques. However, the extent to which IR is associated with AD pathology in the cognitively asymptomatic stages of preclinical AD remains unclear. Objective To determine the extent to which IR is linked with amyloid and tau pathology in late-middle-age. Method Cerebrospinal fluid (CSF) samples collected from 113 participants enrolled in the Wisconsin Registry for Alzheimer's Prevention study (mean age = 60.6 years), were assayed for AD-related markers of interest: Aβ42, P-Tau181, and T-Tau. IR was determined using the Homeostatic Model Assessment for Insulin Resistance (HOMA-IR). Linear regression was used to test the effect of IR, and APOE ε4, on tau and amyloid pathology. We hypothesized that greater IR would be associated with higher CSF P-Tau181 and T-Tau, and lower CSF Aβ42. Results No significant main effects of HOMA-IR on P-Tau181, T-Tau, or Aβ42 were observed; however, significant interactions were observed between HOMA-IR and APOE ε4 on CSF markers related to tau. Among APOE ε4 carriers, higher HOMA-IR was associated with higher P-Tau181 and T-Tau. Among APOE ε4 non-carriers, HOMA-IR was negatively associated with P-Tau181 and T-Tau. We found no effects of IR on Aβ42 levels in CSF. Conclusion IR among asymptomatic APOE ε4 carriers was associated with higher P-Tau181 and T-Tau in late-middle age. The results suggest that IR may contribute to tau-related neurodegeneration in preclinical AD. The findings may have implications for developing prevention strategies aimed at modifying IR in mid-life. PMID:25812851
Two-Yukawa fluid at a hard wall: Field theory treatment
Energy Technology Data Exchange (ETDEWEB)
Kravtsiv, I.; Patsahan, T.; Holovko, M. [Institute for Condensed Matter Physics, National Academy of Sciences, 1 Svientsitskii St., 79011 Lviv (Ukraine); Caprio, D. di [Institute of Research of Chimie Paris, CNRS-Chimie ParisTech, 11 rue Pierre et Marie Curie, 75005 Paris (France)
2015-05-21
We apply a field-theoretical approach to study the structure and thermodynamics of a two-Yukawa fluid confined by a hard wall. We derive mean field equations allowing for numerical evaluation of the density profile which is compared to analytical estimations. Beyond the mean field approximation, analytical expressions for the free energy, the pressure, and the correlation function are derived. Subsequently, contributions to the density profile and the adsorption coefficient due to Gaussian fluctuations are found. Both the mean field and the fluctuation terms of the density profile are shown to satisfy the contact theorem. We further use the contact theorem to improve the Gaussian approximation for the density profile based on a better approximation for the bulk pressure. The results obtained are compared to computer simulation data.
Collapse and dispersal of a homogeneous spin fluid in Einstein-Cartan theory
Hashemi, Mostafa; Ziaie, Amir Hadi
2014-01-01
We study the collapse process of a massive star whose matter content is a Weyssenhoff fluid and show that the spin of matter, in the context of a negative pressure, acts against the pull of gravity. Such a mechanism and decelerates the collapse dynamics to finally replace the spacetime singularity by a bounce after which an expanding phase starts. We analyze the solutions in the large and small scale factor regimes and show that the scale factor never vanishes but reaches a minimum in the later one. Depending on the model parameters, there can be found a minimum value for the boundary of the collapsing star or correspondingly a threshold value for the mass content below which the formation of a dynamical horizon can be avoided. Our results are supported by a thorough numerical analysis.
Study of high-pressure adsorption from supercritical fluids by the potential theory
DEFF Research Database (Denmark)
Monsalvo, Matias Alfonso; Shapiro, Alexander
2009-01-01
the adsorbed and the gas phases. We have also evaluated the performance of the classical Soave-Redlich-Kwong (SRK) EoS. The fluid-solid interactions are described by simple Dubinin-Radushkevich-Astakhov (DRA) potentials. In addition, we test the performance of the 10-4-3 Steele potential. It is shown...... that application of sPC-SAFT slightly improves the performance of the MPTA and that in spite of its simplicity, the DRA model can be considered as an accurate potential, especially, for mixture adsorption. We show that, for the sets of experimental data considered in this work, the MPTA is capable of predicting...... adsorption of pure components and binary mixtures in wide ranges of pressure and temperature. A good agreement with the theoretical predictions is achieved in most of the cases. The MPTA is capable to correctly describe complex physical behavior observed at supercritical/high-pressure conditions. Some...
Directory of Open Access Journals (Sweden)
Carlos Cruchaga
2010-09-01
Full Text Available Alzheimer's Disease (AD is a complex and multifactorial disease. While large genome-wide association studies have had some success in identifying novel genetic risk factors for AD, case-control studies are less likely to uncover genetic factors that influence progression of disease. An alternative approach to identifying genetic risk for AD is the use of quantitative traits or endophenotypes. The use of endophenotypes has proven to be an effective strategy, implicating genetic risk factors in several diseases, including anemia, osteoporosis and heart disease. In this study we identify a genetic factor associated with the rate of decline in AD patients and present a methodology for identification of other such factors. We have used an established biomarker for AD, cerebrospinal fluid (CSF tau phosphorylated at threonine 181 (ptau(181 levels as an endophenotype for AD, identifying a SNP, rs1868402, in the gene encoding the regulatory sub-unit of protein phosphatase B, associated with CSF ptau(181 levels in two independent CSF series (P(combined = 1.17 x 10(-05. We show no association of rs1868402 with risk for AD or age at onset, but detected a very significant association with rate of progression of disease that is consistent in two independent series (P(combined = 1.17 x 10(-05. Our analyses suggest that genetic variants associated with CSF ptau(181 levels may have a greater impact on rate of progression, while genetic variants such as APOE4, that are associated with CSF Aβ(42 levels influence risk and onset but not the rate of progression. Our results also suggest that drugs that inhibit or decrease tau phosphorylation may slow cognitive decline in individuals with very mild dementia or delay the appearance of memory problems in elderly individuals with low CSF Aβ(42 levels. Finally, we believe genome-wide association studies of CSF tau/ptau(181 levels should identify novel genetic variants which will likely influence rate of progression of
Institute of Scientific and Technical Information of China (English)
YU Yang-Xin; WU Jian-Zhong; YOU Feng-Qi; GAO Guang-Hua
2005-01-01
@@ An extended test-particle method is used to predict the inter- and intramolecular correlation functions of freely jointed hard-sphere-Yukawa-chain fluids by calculating the segmental density distributions around a fixed seg ment. The underlying density functional theory for chain fluids is based on a modified fundamental measure theory for the hard-sphere repulsive and a mean-field approximation for attraction between different segments.The calculated intra- and inter-molecular distribution functions agree well with the results from Monte Carlo simulations, better than those from alternative approaches.
Fluid damping phenomena in a slender microbeam modelled on nonclassical theory
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Belardinelli P.
2014-01-01
Full Text Available This work deals with the evaluation of the squeeze-film damping in an electrically-actuated microbeam considering the eﬀects of an imposed static deﬂection. The model presents a reliable modelling of the mechanical behaviour by improving the classical approach with the features of the strain-gradient elasticity theory. Taking into account a correction of the electric actuation for the fringing field effects, a parametric analysis is performed. The work pays attention to evaluate the damping force on the beam surface both in small static deﬂection regime and near the static pull-in. The results show that the correction for the finiteness of beam edges and the high-order material parameters aﬀect the response only at large deﬂections. A brief study on the static behaviour is carried out highlighting how the response is affected by the strain-gradient elasticity theory. A parametric analysis of the damping force is presented and the properties of the cut-off point are studied.
Fluid models for kinetic effects on coherent nonlinear Alfvacute en waves. I. Fundamental theory
International Nuclear Information System (INIS)
Collisionless regime kinetic models for coherent nonlinear Alfvacute en wave dynamics are studied using fluid moment equations with an approximate closure anzatz. Resonant particle effects are modeled by incorporating an additional term representing dissipation akin to parallel heat conduction. Unlike collisional dissipation, parallel heat conduction is presented by an integral operator. The modified derivative nonlinear Schroedinger equation thus has a spatially nonlocal nonlinear term describing the long-time evolution of the envelope of parallel-propagating Alfvacute en waves, as well. Coefficients in the nonlinear terms are free of the (1-β)-1 singularity usually encountered in previous analyses, and have a very simple form that clarifies the physical processes governing the large-amplitude Alfvacute enic nonlinear dynamics. The nonlinearity appears via coupling of an Alfvacute enic mode to a kinetic ion-acoustic mode. Damping of the nonlinear Alfvacute en wave appears via strong Landau damping of the ion-acoustic wave when the electron-to-ion temperature ratio is close to unity. For a (slightly) obliquely propagating wave, there are finite Larmor radius corrections in the dynamical equation. This effect depends on the angle of wave propagation relative to B0 and vanishes for the limit of strictly parallel propagation. Explicit magnetic perturbation envelope equations amenable to further analysis and numerical solution are obtained. Implications of these models for collisionless shock dynamics are discussed. copyright 1996 American Institute of Physics
Free glycogen in vaginal fluids is associated with Lactobacillus colonization and low vaginal pH.
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Paria Mirmonsef
Full Text Available Lactobacillus dominates the lower genital tract microbiota of many women, producing a low vaginal pH, and is important for healthy pregnancy outcomes and protection against several sexually transmitted pathogens. Yet, factors that promote Lactobacillus remain poorly understood. We hypothesized that the amount of free glycogen in the lumen of the lower genital tract is an important determinant of Lactobacillus colonization and a low vaginal pH.Free glycogen in lavage samples was quantified. Pyrosequencing of the 16S rRNA gene was used to identify microbiota from 21 African American women collected over 8-11 years.Free glycogen levels varied greatly between women and even in the same woman. Samples with the highest free glycogen had a corresponding median genital pH that was significantly lower (pH 4.4 than those with low glycogen (pH 5.8; p<0.001. The fraction of the microbiota consisting of Lactobacillus was highest in samples with high glycogen versus those with low glycogen (median = 0.97 vs. 0.05, p<0.001. In multivariable analysis, having 1 vs. 0 male sexual partner in the past 6 months was negatively associated, while BMI ≥30 was positively associated with glycogen. High concentrations of glycogen corresponded to higher levels of L. crispatus and L. jensenii, but not L. iners.These findings show that free glycogen in genital fluid is associated with a genital microbiota dominated by Lactobacillus, suggesting glycogen is important for maintaining genital health. Treatments aimed at increasing genital free glycogen might impact Lactobacillus colonization.
Directory of Open Access Journals (Sweden)
D. Schertzer
1996-01-01
. It had an appropriate editorial structure, in particular a large number of editors covering a wide range of methodologies, expertises and schools. At least two of its sections (Scaling and Multifractals, Turbulence and Diffusion were directly related to the topics of the workshop, in any case contributors were invited to choose their editor freely. 2 Goals of the Workshop The objective of this meeting was to enhance the confrontation between turbulence theories and empirical data from geophysics and astrophysics fluids with very high Reynolds numbers. The importance of these data seems to have often been underestimated for the evaluation of theories of fully developed turbulence, presumably due to the fact that turbulence does not appear as pure as in laboratory experiments. However, they have the great advantage of giving access not only to very high Reynolds numbers (e.g. 1012 for atmospheric data, but also to very large data sets. It was intended to: (i provide an overview of the diversity of potentially available data, as well as the necessary theoretical and statistical developments for a better use of these data (e.g. treatment of anisotropy, role of processes which induce other nonlinearities such as thermal instability, effect of magnetic field and compressibility ... , (ii evaluate the means of discriminating between different theories (e.g. multifractal intermittency models or to better appreciate the relevance of different notions (e.g. Self-Organized Criticality or phenomenology (e.g. filaments, structures, (iii emphasise the different obstacles, such as the ubiquity of catastrophic events, which could be overcome in the various concerned disciplines, thanks to theoretical advances achieved. 3 Outlines of the Workshop During the two days of the workshop, the series of presentations covered many manifestations of turbulence in geophysics, including: oceans, troposphere, stratosphere, very high atmosphere, solar wind, giant planets, interstellar clouds
Hydrodynamic theory of partially degenerate electron-hole fluids in semiconductors
Akbari-Moghanjoughi, M.; Eliasson, B.
2016-10-01
A quantum hydrodynamic theory for high-frequency electron-hole Langmuir and acoustic-like oscillations as well as static charge shielding effects in arbitrarily doped semiconductors is presented. The model includes kinetic corrections to the quantum statistical pressure and to the quantum Bohm potential for partially degenerate electrons and holes at finite temperatures. The holes contribute to the oscillations and screening effects in semiconductors in a similar manner as real particles. The dielectric functions are derived in the high-frequency limit for wave excitations and in the low-frequency limit for the study of static screening. The dispersion relation for the Langmuir and acoustic-like oscillations is examined for different parameters of doped silicon (Si). Some interesting properties and differences of electron hole dynamical behavior in N- and P-type Si are pointed out. Holes are also observed to enhance an attractive charge shielding effect when the semiconductor is highly acceptor-doped.
Thorwart, Anna
2010-01-01
Theories of associative learning describe learning about the relationship between two events, e.g. the eating of an apple and subsequent stomach ache. One important classification of these models is based on the stimulus representation they suppose. Whereas elemental models assume that the representations of a stimulus compound consist of representations of its components establishing associations, configural models propose that s...
Dennesen, P.; Veerman, E.; Nieuw Amerongen, A. van; Jacobs, J.; Kessels, A.G.H.; Keijbus, P. van den; Ramsay, G.; Ven, A.J.A.M. van der
2003-01-01
OBJECTIVE: To compare the levels of sulfated mucins in bronchoalveolar lavage fluid (BALF) in ICU patients with ventilator-associated pneumonia (VAP) with those in non-infectious controls, i.e., ventilated ICU patients without VAP, and nonventilated patients. DESIGN AND SETTING: Prospective study in
Li, Huajun; Li, Shuxian; Zheng, Jianfeng; Cai, Chunyan; Ye, Bin; Yang, Jun; Chen, Zhimin
2015-03-01
Enterovirus 71 (EV71) infection can cause severe neurological complications including meningoencephalitis (ME) in some patients with hand, foot and mouth disease (HFMD). However, to date no studies have reported changes in cytokine concentrations and their correlations with clinical variables in patients with ME following EV71 infection. In this study, responses of Th1/Th2 cytokine, including IL-2, IL-4, IL-6, IL-10, TNF-α and IFN-γ, in cerebrospinal fluid (CSF) from patients with EV71-related HFMD with ME and patients with febrile convulsions (FC) were analyzed using cytometric bead array technology. It was found that CSF IL-6 and IFN-γ concentrations were significantly higher in patients with EV71-related ME than in those with FC. Additionally, both CSF IL-6 and IFN-γ concentrations were correlated with CSF cytology, fever duration and duration of hospital stay. More interestingly, a positive correlation between CSF IL-6 and IFN-γ concentrations was observed. Finally, receiver operating characteristic analysis revealed that when a cutoff value of 9.40 pg/mL was set for IL-6, the sensitivity and specificity were 84.5% and 85.5%, respectively, for discriminating EV71-related ME from FC. In conclusion, IL-6 and IFN-γ may be associated with EV71-induced neuropathology. PMID:25611005
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Fanni Haapalinna
2016-07-01
Full Text Available Background: Data on the association of memory performance with cerebrospinal fluid (CSF biomarkers of Alzheimer's disease (AD are inconsistent. The Consortium to Establish a Registry for Alzheimer's Disease neuropsychological battery (CERAD-NB is a commonly used validated cognitive tool; however, only few studies have examined its relationship with CSF biomarkers for AD. We studied the correlation of pathological changes in CSF biomarkers with various CERAD-NB subtests and total scores. Methods: Out of 79 subjects (36 men, mean age 70.5 years, 63 had undergone an assessment of cognitive status with CERAD-NB and a CSF biomarker analysis due to a suspected memory disorder, and 16 were controls with no memory complaint.Results: In women we found a significant correlation between CSF amyloid-beta (Aβ1-42 and several subtests measuring delayed recall. Word List Recall correlated with all markers: Aβ1-42 (r = 0.323, p = 0.035, tau (r = -0.304, p = 0.050 and hyperphosphorylated tau (r = -0.331, p = 0.046. No such correlations were found in men. Conclusions: CSF biomarkers correlate with delayed memory scores in CERAD-NB in women, and women may have more actual AD pathology at the time of the investigations than men.
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Heidi R. Flori
2011-01-01
Full Text Available Introduction. We analyzed a database of 320 pediatric patients with acute lung injury (ALI, to test the hypothesis that positive fluid balance is associated with worse clinical outcomes in children with ALI. Methods. This is a post-hoc analysis of previously collected data. Cumulative fluid balance was analyzed in ml per kilogram per day for the first 72 hours after ALI while in the PICU. The primary outcome was mortality; the secondary outcome was ventilator-free days. Results. Positive fluid balance (in increments of 10 mL/kg/24 h was associated with a significant increase in both mortality and prolonged duration of mechanical ventilation, independent of the presence of multiple organ system failure and the extent of oxygenation defect. These relationships remained unchanged when the subgroup of patients with septic shock (n=39 were excluded. Conclusions. Persistently positive fluid balance may be deleterious to pediatric patients with ALI. A confirmatory, prospective randomized controlled trial of fluid management in pediatric patients with ALI is warranted.
Risk Associated With The Decompression Of High Pressure High Temperature Fluids - Study On Black Oil
DEFF Research Database (Denmark)
Figueroa, D. C.; Fosbøl, P. L.; Thomsen, K.
2015-01-01
Fluids produced from deep underground reservoirs may result in exponential increase in temperature. It is a consequence of adiabatic fluid decompression from the inverse Joule Thomson Effect (JTE). The phenomenon requires analysis in order to avoid any operational risks. This study evaluates...
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Reiner Jumpertz
Full Text Available Rodent experiments have emphasized a role of central fatty acid (FA species, such as oleic acid, in regulating peripheral glucose and energy metabolism. Thus, we hypothesized that central FAs are related to peripheral glucose regulation and energy expenditure in humans. To test this we measured FA species profiles in cerebrospinal fluid (CSF and plasma of 32 individuals who stayed in our clinical inpatient unit for 6 days. Body composition was measured by dual energy X-ray absorptiometry and glucose regulation by an oral glucose test (OGTT followed by measurements of 24 hour (24EE and sleep energy expenditure (SLEEP as well as respiratory quotient (RQ in a respiratory chamber. CSF was obtained via lumbar punctures; FA concentrations were measured by liquid chromatography/mass spectrometry. As expected, FA concentrations were higher in plasma compared to CSF. Individuals with high concentrations of CSF very-long-chain saturated FAs had lower rates of SLEEP. In the plasma moderate associations of these FAs with higher 24EE were observed. Moreover, CSF monounsaturated long-chain FA (palmitoleic and oleic acid concentrations were associated with lower RQs and lower glucose area under the curve during the OGTT. Thus, FAs in the CSF strongly correlated with peripheral metabolic traits. These physiological parameters were most specific to long-chain monounsaturated (C16:1, C18:1 and very-long-chain saturated (C24:0, C26:0 FAs.Together with previous animal experiments these initial cross-sectional human data indicate that central FA species are linked to peripheral glucose and energy homeostasis.
Energy Technology Data Exchange (ETDEWEB)
Pratt, L.R.; Haan, S.W.
1981-02-01
An exact formal theory for the effects of periodic boundary conditions on the equilibrium properties of computer simulated classical many-body systems is developed. This is done by observing that use of the usual periodic conditions is equivalent to the study of a certain supermolecular liquid, in which a supermolecule is a polyatomic molecule of infinite extent composed of one of the physical particles in the system plus all its periodic images. For this supermolecular system in the grand ensemble, all the cluster expansion techniques used in the study of real molecular liquids are directly applicable. As expected, particle correlations are translationally uniform, but explicitly anisotropic. When the intermolecular potential energy functions are of short enough range, or cut off, so that the minimum image method is used, evaluation of the cluster integrals is dramatically simplified. In this circumstance, a large and important class of cluster expansion contributions can be summed exactly, and expressed in terms of the correlation functions which result when the system size is allowed to increase without bound. This result yields a simple and useful approximation to the corrections to the particle correlations due to the use of periodic boundary conditions with finite systems. Numerical application of these results are reported in the following paper.
The fluid mechanics of dark matter formation Why does Jeans's (1902 and 1929) theory fail?
Gibson, C H
1999-01-01
Jeans's (1902 & 1929) linear gravitational instability criterion gives truly spectacular errors in its predictions of cosmological structure formation according to Gibson's (1996) new nonlinear theory. Scales are determined by viscous or turbulent forces, or by diffusivity, at Schwarz length scales L_SV, L_ST, or L_SD, respectively, whichever is larger. By these new criteria, void formation begins in the plasma epoch soon after matter dominates energy, at L approx L_SV = (gamma nu / rho G)^1/2 scales corresponding to protosuperclusters, decreasing to protogalaxies at the plasma-gas transition, where gamma is the rate-of-strain of the expanding universe, nu is the kinematic viscosity, rho is the density, and G is Newton's gravitational constant. Condensation of the primordial gas occurs at mass scales a trillion times less than the Jeans mass to form a `fog' of micro-brown-dwarf (MBD) particles that persist as the galactic baryonic dark matter, as reported by Schild (1996) from quasar-microlensing studies....
LENUS (Irish Health Repository)
McNally, P
2011-02-01
Gastro-oesophageal reflux is common in children with cystic fibrosis (CF) and is thought to be associated with pulmonary aspiration of gastric contents. The measurement of pepsin in bronchoalveolar lavage (BAL) fluid has recently been suggested to be a reliable indicator of aspiration. The prevalence of pulmonary aspiration in a group of children with CF was assessed and its association with lung inflammation investigated.
Association of Brucella Meningoencephalitis with Cerebrospinal Fluid Shunt in A Child: A Case Report
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Babak ABDINIA
2013-02-01
Full Text Available How to Cite This Article: Abdinia B, Barzegar M, Maleki M, Behbod H, Oskoui Sh. Association of Brucella Meningoencephalitis with Cerebrospinal Fluid Shunt in a Child: a Case Report. Iran J Child Neurol. 2013 Winter:7(1:35-38. Brucellosis is an endemic zoonosis in Iran. It is a systemic infection that can involve any organs or systems of the body and have variable presentations. Ventriculoperitoneal (VP shunt infections due to brucellosis have been rarely reported in the literatures.This is the history of a four years old boy who developed Brucella meningoencephalitis at the age of 42 months, whilst he had a VP shunt in situ for hydrocephalus treatment. Also, he presented brucellosis as acute abdomen. This patient was treated with trimethoprim-sulfamethoxazole, gentamicin and rifampicin. The shunt was extracted and all clinical and laboratory test abnormalities subsided through this management.We propose that in a patient with Brucella meningoencephalitis, the cerebrospinal fluid shunt system can be extracted and treatment with appropriate combination of antibiotics could be successful. Moreover, it shows that brucellosis should be considered in the differential diagnosis for acute abdomen and ascites in endemic regions.References1. Hasanjani Roushan MR, Mohrez M, Samilnejad Gangi SM, Soleimani Amiri MJ, Hajiahmadi M. Epidemiological features and clinical manifestations in 469 adult patients with brucellosis in babol, Northern Iran. Epidemiol infect 2004;132(6:1109-142. Bouza E, García de la Torre M, Parras F, Guerrero A, Rodríguez-Créixems M, Gobernado J. Brucellar meningitis. Brucellar meningitis. Rev Infect Dis 1987; 9(4:810-22.3. Young EJ. Brucella species. In: Mandell GL, Bennett JE, Dolin R, eds. Mandell, Douglas and Bennetts Õs Principles and Practice of Infectious Diseases. 5th ed. New York: Churchill Livingstone; 2000. p. 86-93.4. Feiz J, Sabbaghian H, Miralai M. Brucellosis due to Brucella
Eto, Kumi; Koch, Pamela; Contento, Isobel R.; Adachi, Miyuki
2011-01-01
Objective: To examine associations between Theory of Planned Behavior variables and the family meal frequency. Methods: Fifth-through seventh-grade students (n = 236) completed a self-administered questionnaire in their classrooms. The relationships between Theory of Planned Behavior variables (intention, attitudes, subjective norms, and perceived…
Risk factors associated with uterine fluid after breeding caused by Streptococcus zooepidemicus.
Christoffersen, Mette; Söderlind, Maja; Rudefalk, Sofia Rydemann; Pedersen, Hanne Gervi; Allen, Joanne; Krekeler, Natali
2015-11-01
Infectious endometritis is a major cause of infertility in the mare and inflicts major losses on the equine breeding industry. The ability of the mare to eliminate uterine infections has been studied intensively for decades; however, despite identification of several factors contributing to the multifactorial pathogenesis and improved treatment, infectious endometritis remains a significant problem in a subpopulation of broodmares. Streptococcus equi subsp. zooepidemicus (S. zooepidemicus) is one of the most commonly isolated pathogens from the uterus of mares, suffering from infectious endometritis. Its ability to cause chronic latent infection by residing deep within the endometrial tissue has previously been described. The aim of the present study was to correlate different mare risk factors to infectious endometritis and pregnancy rates in broodmares and to investigate whether clonal or genetically distinct S. zooepidemicus strains isolated from mares with endometritis were associated with mare risk factors and the outcome of insemination. Mares (N = 152) were examined after natural cover, and 20% (31 mares) had intrauterine fluid (IUF) accumulation. Fifty-five percent (16 of 29) of the mares with IUF had infectious endometritis, and S. zooepidemicus was isolated in 81% (13 of 16) of these mares. Significantly more resting mares had IUF compared with foaling mares, and the foaling mares had the highest prevalence of positive bacterial growth from the uterine swab. The per-cycle pregnancy rate for the study was 63%. Pregnancy rate was significantly negatively affected by increased age (>12 years) and increased parity (>4), and the lowest pregnancy rate was observed in resting mares compared with foaling, barren, and maiden mares. Up to four S. zooepidemicus isolates were selected from each mare with growth of S. zooepidemicus from the uterine swab sample and further characterized by pulsed-field gel electrophoresis. In total, S. zooepidemicus isolates from
James, Rachael H.; Green, Darryl R. H.; Stock, Michael J.; Alker, Belinda J.; Banerjee, Neil R.; Cole, Catherine; German, Christopher R.; Huvenne, Veerle A. I.; Powell, Alexandra M.; Connelly, Douglas P.
2014-08-01
The East Scotia Ridge is an active back-arc spreading centre located to the west of the South Sandwich island arc in the Southern Ocean. Initial exploration of the ridge by deep-tow surveys provided the first evidence for hydrothermal activity in a back-arc setting outside of the western Pacific, and we returned in 2010 with a remotely operated vehicle to precisely locate and sample hydrothermal sites along ridge segments E2 and E9. Here we report the chemical and isotopic composition of high- and low-temperature vent fluids, and the mineralogy of associated high-temperature chimney material, for two sites at E2 (Dog’s Head and Sepia), and four sites at E9 (Black & White, Ivory Tower, Pagoda and Launch Pad). The chemistry of the fluids is highly variable between the ridge segments. Fluid temperatures were ∼350 °C at all vent sites except Black & White, which was significantly hotter (383 °C). End-member chloride concentrations in E2 fluids (532-536 mM) were close to background seawater (540 mM), whereas Cl in E9 fluids was much lower (98-220 mM) indicating that these fluids are affected by phase separation. Concentrations of the alkali elements (Na, Li, K and Cs) and the alkaline earth elements (Ca, Sr and Ba) co-vary with Cl, due to charge balance constraints. Similarly, concentrations of Mn and Zn are highest in the high Cl fluids but, by contrast, Fe/Cl ratios are higher in E9 fluids (3.8-8.1 × 10-3) than they are in E2 fluids (1.5-2.4 × 10-3) and fluids with lowest Cl have highest Cu. Although both ridge segments are magmatically inflated, there is no compelling evidence for input of magmatic gases to the vent fluids. Fluid δD values range from 0.2‰ to 1.5‰, pH values (3.02-3.42) are not especially low, and F concentrations (34.6-54.4 μM) are lower than bottom seawater (62.8 μM). The uppermost sections of conjugate chimney material from E2, and from Ivory Tower and Pagoda at E9, typically exhibit inner zones of massive chalcopyrite enclosed
Institute of Scientific and Technical Information of China (English)
WANG Haijun; HONG Xiaozhong; GU Fang; BA Xinwu
2006-01-01
The influence of hydrogen bonds on the physical and chemical properties of hydrogen bonding fluid system of AaDd type is investigated from two viewpoints by the principle of statistical mechanics. In detail, we proposed two new ways that can be used to obtain the equilibrium size distribution of the hydrogen bonding clusters, and derived the analytical expression of a relationship between the hydrogen bonding free energy and hydrogen bonding degree. For the nonlinear hydrogen bonding systems, it is shown that the sol-gel phase transition can take place under proper conditions, which is further proven to be a kind of geometrical phase transition rather than a thermodynamic one. Moreover, several problems associated with the geometrical phase transition and liquid-solid phase transition in nonlinear hydrogen bonding systems are discussed.
Some Deviations Associated With Vector Perturbation Diffraction Theory
Stover, John C.; Hourmand, Bahrarr
1985-01-01
Last year at this conference our lab presented some data which strongly supports the use of the vector perturbation relationship between light scattered from smooth surfaces and the surface power spectral density (PSD). Last year's data showed that a consistent answer was obtained for the PSD for measurements taken with S and P polarization, with incident angles up to 45', for positive and negative sweeps, and for one and two dimensional samples. If in fact the theoretical relationship is correct then this must be the case, as the PSD is determined by a combination of surface topography and the scattering situation (geometry, polarization, wavelength, etc.). It appears, however that for large scatter angles (>700) and for large angles of incidence (>60 °) there is some deviation in the calculated PSD. In addition, the high angle scatter region is an area where a scatterometer with a semicircular detector sweep loses the one-to-one relationship between detector position and surface spatial frequency. Or, in other words, light diffracted to high scatter angles from single spatial frequencies appears over a small band on the observation semicircle instead of a diffraction limited point. Fata supporting these two deviations is presented. Although they are not regarded as serious violations of the vector perturbation theory they do impose a limit on the useful range over which the PSD may be calculated.
International Nuclear Information System (INIS)
The Nopal I uranium (U) deposit, Pena Blanca District, Mexico, largely consists of secondary U6+ minerals, which occur within a breccia pipe mainly hosted by the 44 Ma Nopal and Colorados volcanic formations. These two units overly the Pozos conglomerate formation and Cretaceous limestone. Three new vertical diamond drill holes (DDHs) were recently drilled at Nopal I. DDH-PB1 with continuous core was drilled through the Nopal I deposit and two additional DDHs were drilled ∼50 m on either side of the cored hole. These DDHs terminate 20 m below the current water table, thus allowing the detection of possible gradients in radionuclide contents resulting from transport from the overlying uranium deposit. Primary uraninite within the main ore body is rare and fine-grained (∼50 micrometers), thus making geochronology of the Nopal I deposit very difficult. Uranium, lead and oxygen isotopes can be used to study fluid-uraninite interaction, provided that the analyses are obtained on the micro-scale. Secondary ionization mass spectrometry (SIMS) permits in situ measurement of isotopic ratios with a spatial resolution on the scale of a few (micro)m. Preliminary U-Pb results show that uraninite from the main ore body gives an age of 32 ± 8 Ma, whereas uraninite from the uraniferous Pozos conglomerate that lies nearly 100 m below the main ore body and 25 meters above the water table, gives a U-Pb age that is 18O = -10.8(perthousand), whereas the uraninite within the Pozos conglomerate has a (delta)18O = +1.5(perthousand). If it is assumed that both uraninites precipitated from meteoric water ((delta)18O = -7(perthousand)), then calculated precipitation temperatures are 55 C for the uraninite from the ore body and 20 C for uraninite hosted by the Pozos conglomerate. These temperatures are consistent with previous studies that calculated precipitation temperatures for clay minerals associated with uraninite
Fialko, O.; Kovalchuk, L.
2002-12-01
Ample field observations in areas of known oil and gas deposists reveal an existence of excess temperature anomalies associated with the hydrocarbon-bearing structures. These observations are explained in terms of upward migration of heated fluids. In this case there is a deviation from a linear temperature distribution with depth due to a convective component of the heat flux. We propose a new method based on in situ measurements of the thermal field that allows one to take into account both conductive and convective components of the heat flow. In addition to the usual measurements of temperature, we determine the the curvature of the geothermograms, which characterizes the degree of deviation of the heat transfer from a conductive regime. Correspondingly, in addition to the commonly used geothermal gradient, we introduce new parameters, such as the radius of curvature of the geotherms (R), the coefficient of curvature of the geotherms (K), the Knudsen criterion (Kn), and parameter F. We present analytic expressions for the determination of these parameters, and evaluate these parameters for several natural objects. We demonstrate the usefulness of the proposed method for 1) forecasts of the presence of the deep-seated hydrocarbon deposits; 2) estimates of the abnornally elevated gas content in the deep-seated coal deposits, and determination of zones with high risk of methane bursts; 3) studies of the hydro-geothermal conditions of the geothermal areas; 4) determination and localization of leaks along the buried industrial pipelines. We present examples illustrating the application of our method for the abovementioned tasks.
Maternal and fetal characteristics associated with meconium-stained amniotic fluid
DEFF Research Database (Denmark)
Balchin, Imelda; Whittaker, John C; Lamont, Ronald F;
2011-01-01
To estimate the rates of meconium-stained amniotic fluid (AF) and adverse outcome in relation to gestational age and racial group, and to investigate the predictors of meconium-stained AF.......To estimate the rates of meconium-stained amniotic fluid (AF) and adverse outcome in relation to gestational age and racial group, and to investigate the predictors of meconium-stained AF....
Thermophysical Properties of Fluids and Fluid Mixtures
Energy Technology Data Exchange (ETDEWEB)
Sengers, Jan V.; Anisimov, Mikhail A.
2004-05-03
The major goal of the project was to study the effect of critical fluctuations on the thermophysical properties and phase behavior of fluids and fluid mixtures. Long-range fluctuations appear because of the presence of critical phase transitions. A global theory of critical fluctuations was developed and applied to represent thermodynamic properties and transport properties of molecular fluids and fluid mixtures. In the second phase of the project, the theory was extended to deal with critical fluctuations in complex fluids such as polymer solutions and electrolyte solutions. The theoretical predictions have been confirmed by computer simulations and by light-scattering experiments. Fluctuations in fluids in nonequilibrium states have also been investigated.
Schertzer, D.; Falgarone, E.
appropriate editorial structure, in particular a large number of editors covering a wide range of methodologies, expertises and schools. At least two of its sections (Scaling and Multifractals, Turbulence and Diffusion) were directly related to the topics of the workshop, in any case contributors were invited to choose their editor freely. 2 Goals of the Workshop The objective of this meeting was to enhance the confrontation between turbulence theories and empirical data from geophysics and astrophysics fluids with very high Reynolds numbers. The importance of these data seems to have often been underestimated for the evaluation of theories of fully developed turbulence, presumably due to the fact that turbulence does not appear as pure as in laboratory experiments. However, they have the great advantage of giving access not only to very high Reynolds numbers (e.g. 1012 for atmospheric data), but also to very large data sets. It was intended to: (i) provide an overview of the diversity of potentially available data, as well as the necessary theoretical and statistical developments for a better use of these data (e.g. treatment of anisotropy, role of processes which induce other nonlinearities such as thermal instability, effect of magnetic field and compressibility ... ), (ii) evaluate the means of discriminating between different theories (e.g. multifractal intermittency models) or to better appreciate the relevance of different notions (e.g. Self-Organized Criticality) or phenomenology (e.g. filaments, structures), (iii) emphasise the different obstacles, such as the ubiquity of catastrophic events, which could be overcome in the various concerned disciplines, thanks to theoretical advances achieved. 3 Outlines of the Workshop During the two days of the workshop, the series of presentations covered many manifestations of turbulence in geophysics, including: oceans, troposphere, stratosphere, very high atmosphere, solar wind, giant planets, interstellar clouds... up to the
Kou, Jisheng
2015-08-01
Surface tension significantly impacts subsurface flow and transport, and it is the main cause of capillary effect, a major immiscible two-phase flow mechanism for systems with a strong wettability preference. In this paper, we consider the numerical simulation of the surface tension of multi-component mixtures with the gradient theory of fluid interfaces. Major numerical challenges include that the system of the Euler-Lagrange equations is solved on the infinite interval and the coefficient matrix is not positive definite. We construct a linear transformation to reduce the Euler-Lagrange equations, and naturally introduce a path function, which is proven to be a monotonic function of the spatial coordinate variable. By using the linear transformation and the path function, we overcome the above difficulties and develop the efficient methods for calculating the interface and its interior compositions. Moreover, the computation of the surface tension is also simplified. The proposed methods do not need to solve the differential equation system, and they are easy to be implemented in practical applications. Numerical examples are tested to verify the efficiency of the proposed methods. © 2014 Elsevier B.V.
Sobkowicz, H M; Holy, J; Scott, G L
1990-07-01
The intercalated body is a newly discovered organelle in the inner and outer spiral sulcus cells of the mouse organ of Corti. The organelle was found in the cochleas of 14-day and older intact mice and in organs in culture of corresponding ages. The organelle consists of a stack of interconnected cisternae of endoplasmic reticulum and of membrane bound rodlets that are intercalated between, and run parallel to, the cisternae. The cisternal membranes are predominantly smooth, but some may display ribosomes. Most rodlets are from 1 to 2 microns long, about 0.1 micron wide, and contain electron dense material. Mitochondria are commonly associated with or incorporated into the organelle. Some electron micrographs suggest that the rodlets may originate from modified mitochondria. It is our impression that the formation of the organelle begins with the apposition of cisternae and mitochondria. Cisternal-associated mitochondria appear to constrict, elongate, and lose their inner membranes. In both the intact animal and in culture, the cells of the inner and outer spiral sulci display microvilli, apical junctional complexes, lateral intercellular spaces containing interdigitating cell processes, and appear to be involved in fluid formation. Moreover, in culture, the cells of inner and outer spiral sulci as well as some cells proliferating in the outgrowth zone participate in fluid formation, producing large fluid pockets. All these cells commonly contain intercalated bodies. It is possible that in the intact animal, as in culture, intercalated bodies may play a role in fluid regulation in the immediate vicinity of the hair cells.
Institute of Scientific and Technical Information of China (English)
付东
2004-01-01
An analytical equation of state (EOS) for hard core Asakura-Oosawa (AO) fluid is established by combining the AO potential, the first-order perturbation theory and the radial distribution function (RDF) for the hard sphere fluid. The phase equilibria are studied by using the renormalization-group (RG) theory. The obtained results agree well with the simulation data. Investigation shows that the attractive range parameter plays an important role in the phase equilibria for AO fluid.
Directory of Open Access Journals (Sweden)
Magee G
2013-06-01
Full Text Available Glenn Magee,1 Art Zbrozek21Premier Research Services, Charlotte, NC, USA; 2CSL Behring, King of Prussia, PA, USABackground: Fluid overload, including transfusion-associated circulatory overload (TACO, is a serious complication of fresh frozen plasma (FFP transfusion. The incidence of fluid overload is underreported and its economic impact is unknown. An evaluation of fluid overload cases in US hospitals was performed to assess the impact of fluid overload on length and cost of hospital stay.Study design and methods: Retrospective analysis was performed using a clinical and economic database covering >600 US hospitals. Data were collected for all inpatients discharged during 2010 who received ≥1 unit FFP during hospitalization. Incidence of fluid overload was determined through International Classification of Diagnosis (ICD-9 codes. Multivariate regression analysis was performed for primary outcome measures: hospital length of stay (LOS and total hospital costs.Results: Data were analyzed for 129,839 FFP-transfused patients, of whom 4,138 (3.2% experienced fluid overload (including TACO. Multivariate analysis, adjusting for baseline characteristics, found that increased LOS and hospital costs were independently associated with fluid overload. Patients diagnosed with fluid overload had longer mean LOS (12.9 days versus 10.0 days; P < 0.001 and higher mean hospital cost per visit ($46,644 versus $32,582; P < 0.001 compared with patients without fluid overload.Conclusion: For a population of US inpatients who received FFP during hospitalization, fluid overload was associated with a 29% increase in LOS and a $14,062 increase in hospital costs per visit. These findings suggest that the incidence of fluid overload in the general population is greater than historically reported. A substantial economic burden may be associated with fluid overload in the US.Keywords: fresh frozen plasma, fluid overload, hospital costs, hypervolemia, length of stay
Cardace, D.; Hoehler, T.; Foster, A. L.
2009-12-01
Serpentinization - the aqueous alteration of ultramafic rocks - generates H2 and other reduced compounds capable of fueling microbial metabolism, and is therefore considered a potential mechanism for the long-term support of subsurface life. This potential may be constrained, however, by rates of serpentinization (corresponding to magnitude of energy flux) and by potentially detrimental co-evolving fluid chemistry - particularly elevated pH. We conducted an initial characterization of the chemistry and associated biological potential of springs and gas seeps associated with two distinct serpentinizing systems in the northwestern Fiordland of New Zealand’s south island. Fluid or gas chemistry, including H2 concentrations, was characterized and used to model energy availability associated with several potential microbial metabolisms; the presence of organisms having targeted metabolisms (methanogenesis, sulfate reduction, iron reduction) was assayed in parallel using quantitative PCR. Serpentinization in Fiordland was tracked in two specific locations. First, the Anita Ultramafites (AU) exposed at Poison Bay are likely ultramafic intrusive rocks within a 3-4 km wide shear zone of deformed gneisses and dunite mylonites (Hill, 1995), which have undergone amphibolite facies metamorphism during continental extension (Gibson, 1990) and now generate gas that escapes from depth along fault networks. Second, along the western edge of the Dun Mountain Ophiolite Belt in the Cascade River Valley, located NW of Milford Sound, deep fluids interact structurally with the Alpine Fault in the ultramafic subsurface; where those fluids escape to the surface, travertine-depositing subaerial springs cover an area of ~100 m2 on a serpentinized talus slope (Aitchison, 1985). Seep fluids from both sites have high pH due to hydroxide solution related to serpentinization, and CaCO3 terraces at the latter site testify to elevated Ca in fluids that reacts with atmospheric CO2 at Earth
Jacek Waniewski; Stefan Antosiewicz; Daniel Baczynski; Jan Poleszczuk; Mauro Pietribiasi; Bengt Lindholm; Zofia Wankowicz
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 ag...
Energy Technology Data Exchange (ETDEWEB)
M. Fayek; P. Goodell; M. Ren; A. Simmons
2005-07-11
The Nopal I uranium (U) deposit, Pena Blanca District, Mexico, largely consists of secondary U{sup 6+} minerals, which occur within a breccia pipe mainly hosted by the 44 Ma Nopal and Colorados volcanic formations. These two units overly the Pozos conglomerate formation and Cretaceous limestone. Three new vertical diamond drill holes (DDHs) were recently drilled at Nopal I. DDH-PB1 with continuous core was drilled through the Nopal I deposit and two additional DDHs were drilled {approx}50 m on either side of the cored hole. These DDHs terminate 20 m below the current water table, thus allowing the detection of possible gradients in radionuclide contents resulting from transport from the overlying uranium deposit. Primary uraninite within the main ore body is rare and fine-grained ({approx}50 micrometers), thus making geochronology of the Nopal I deposit very difficult. Uranium, lead and oxygen isotopes can be used to study fluid-uraninite interaction, provided that the analyses are obtained on the micro-scale. Secondary ionization mass spectrometry (SIMS) permits in situ measurement of isotopic ratios with a spatial resolution on the scale of a few {micro}m. Preliminary U-Pb results show that uraninite from the main ore body gives an age of 32 {+-} 8 Ma, whereas uraninite from the uraniferous Pozos conglomerate that lies nearly 100 m below the main ore body and 25 meters above the water table, gives a U-Pb age that is <1 Ma. Oxygen isotopic analyses show that uraninite from the ore body has a {delta}{sup 18}O = -10.8{per_thousand}, whereas the uraninite within the Pozos conglomerate has a {delta}{sup 18}O = +1.5{per_thousand}. If it is assumed that both uraninites precipitated from meteoric water ({delta}{sup 18}O = -7{per_thousand}), then calculated precipitation temperatures are 55 C for the uraninite from the ore body and 20 C for uraninite hosted by the Pozos conglomerate. These temperatures are consistent with previous studies that calculated precipitation
Rajaram, H.; Birdsell, D.; Lackey, G.; Karra, S.; Viswanathan, H. S.; Dempsey, D.
2015-12-01
The dramatic increase in the extraction of unconventional oil and gas resources using horizontal wells and hydraulic fracturing (fracking) technologies has raised concerns about potential environmental impacts. Large volumes of hydraulic fracturing fluids are injected during fracking. Incidents of stray gas occurrence in shallow aquifers overlying shale gas reservoirs have been reported; whether these are in any way related to fracking continues to be debated. Computational models serve as useful tools for evaluating potential environmental impacts. We present modeling studies of hydraulic fracturing fluid and gas migration during the various stages of well operation, production, and subsequent plugging. The fluid migration models account for overpressure in the gas reservoir, density contrast between injected fluids and brine, imbibition into partially saturated shale, and well operations. Our results highlight the importance of representing the different stages of well operation consistently. Most importantly, well suction and imbibition both play a significant role in limiting upward migration of injected fluids, even in the presence of permeable connecting pathways. In an overall assessment, our fluid migration simulations suggest very low risk to groundwater aquifers when the vertical separation from a shale gas reservoir is of the order of 1000' or more. Multi-phase models of gas migration were developed to couple flow and transport in compromised wellbores and subsurface formations. These models are useful for evaluating both short-term and long-term scenarios of stray methane release. We present simulation results to evaluate mechanisms controlling stray gas migration, and explore relationships between bradenhead pressures and the likelihood of methane release and transport.
Directory of Open Access Journals (Sweden)
Huanmiao Xun
Full Text Available BACKGROUND: The availability of oral fluid HIV rapid testing provides an approach that may have the potential to expand HIV testing in China, especially among most-a-risk populations. There are few investigations about the acceptability of oral fluid HIV testing among most-at-risk populations in China. METHOD: A cross-sectional study with men who have sex with men (MSM, female sex workers (FSW and voluntary counseling and testing (VCT clients was conducted in three cities of Shandong province, China from 2011 to 2012. Data were collected by face-to-face questionnaire. RESULTS: About 71% of participants were willing to accept the oral fluid HIV rapid testing, and home HIV testing was independently associated with acceptability of the new testing method among MSM, FSW and VCT clients (AOR of 4.46, 3.19 and 5.74, respectively. Independent predictors of oral fluid HIV rapid testing acceptability among MSM were having ever taken an oral fluid HIV rapid test (AOR= 15.25, having ever taken an HIV test (AOR= 2.07, and education level (AOR= 1.74. Engagement in HIV-related risk behaviors (AOR= 1.68 was an independent predictor of acceptability for FSW. Having taken an HIV test (AOR= 2.85 was an independent predictor of acceptability for VCT clients. The primary concern about the oral fluid HIV testing was accuracy. The median price they would pay for the testing ranged from 4.8 to 8.1 U.S. dollars. CONCLUSION: High acceptability of oral fluid HIV rapid testing was shown among most-at-risk populations. Findings provide support for oral rapid HIV testing as another HIV prevention tool, and provide a backdrop for the implementation of HIV home testing in the near future. Appropriate pricing and increased public education through awareness campaigns that address concerns about the accuracy and safety of the oral fluid HIV rapid testing may help increase acceptability and use among most-at-risk populations in China.
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
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.
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.
Frederick, Jennifer Mary
older than the host sediment. Old pore fluid age may reflect complex flow patterns, such a fluid focusing, which can cause significant lateral migration as well as regions where downward flow reverses direction and returns toward the seafloor. Longer pathlines can produce pore fluid ages much older than that expected with a one-dimensional compaction model. For steady-state models with geometry representative of Blake Ridge (USA), a well-studied hydrate province, pore fluid ages beneath regions of topography and within fractured zones can be up to 70 Ma old. Results suggest that the measurements of 129-I/127-I reflect a mixture of new and old pore fluid. However, old pore fluid need not originate at great depths. Methane within pore fluids can travel laterally several kilometers, implying an extensive source region around the deposit. Iodine age measurements support the existence of fluid focusing beneath regions of seafloor topography at Blake Ridge, and suggest that the methane source at Blake Ridge is likely shallow. The response of methane hydrate reservoirs to warming is poorly understood. The great depths may protect deep oceanic hydrates from climate change for the time being because transfer of heat by conduction is slow, but warming will eventually be felt albeit in the far future. On the other hand, unique permafrost-associated methane hydrate deposits exist at shallow depths within the sediments of the circum-Arctic continental shelves. Arctic hydrates are thought to be a relict of cold glacial periods, aggrading when sea levels are much lower and shelf sediments are exposed to freezing air temperatures. During interglacial periods, rising sea levels flood the shelf, bringing dramatic warming to the permafrost- and hydrate-bearing sediments. Permafrost-associated methane hydrate deposits have been responding to warming since the last glacial maximum ~18 kaBP as a consequence of these natural glacial cycles. This `experiment,' set into motion by nature itself
Kohan, Donald E; Lambers Heerspink, Hiddo J; Coll, Blai; Andress, Dennis; Brennan, John J; Kitzman, Dalane W; Correa-Rotter, Ricardo; Makino, Hirofumi; Perkovic, Vlado; Hou, Fan Fan; Remuzzi, Giuseppe; Tobe, Sheldon W; Toto, Robert; Parving, Hans-Henrik; de Zeeuw, Dick
2015-01-01
BACKGROUND AND OBJECTIVES: Endothelin A receptor antagonists (ERAs) decrease residual albuminuria in patients with diabetic kidney disease; however, their clinical utility may be limited by fluid retention. Consequently, the primary objective of this study was to identify predictors for ERA-induced
Butler, William E; Atai, Nadia; Carter, Bob; Hochberg, Fred
2014-01-01
The Richard Floor Biorepository supports collaborative studies of extracellular vesicles (EVs) found in human fluids and tissue specimens. The current emphasis is on biomarkers for central nervous system neoplasms but its structure may serve as a template for collaborative EV translational studies in other fields. The informatic system provides specimen inventory tracking with bar codes assigned to specimens and containers and projects, is hosted on globalized cloud computing resources, and embeds a suite of shared documents, calendars, and video-conferencing features. Clinical data are recorded in relation to molecular EV attributes and may be tagged with terms drawn from a network of externally maintained ontologies thus offering expansion of the system as the field matures. We fashioned the graphical user interface (GUI) around a web-based data visualization package. This system is now in an early stage of deployment, mainly focused on specimen tracking and clinical, laboratory, and imaging data capture in support of studies to optimize detection and analysis of brain tumour-specific mutations. It currently includes 4,392 specimens drawn from 611 subjects, the majority with brain tumours. As EV science evolves, we plan biorepository changes which may reflect multi-institutional collaborations, proteomic interfaces, additional biofluids, changes in operating procedures and kits for specimen handling, novel procedures for detection of tumour-specific EVs, and for RNA extraction and changes in the taxonomy of EVs. We have used an ontology-driven data model and web-based architecture with a graph theory-driven GUI to accommodate and stimulate the semantic web of EV science. PMID:25317275
Butler, William E; Atai, Nadia; Carter, Bob; Hochberg, Fred
2014-01-01
The Richard Floor Biorepository supports collaborative studies of extracellular vesicles (EVs) found in human fluids and tissue specimens. The current emphasis is on biomarkers for central nervous system neoplasms but its structure may serve as a template for collaborative EV translational studies in other fields. The informatic system provides specimen inventory tracking with bar codes assigned to specimens and containers and projects, is hosted on globalized cloud computing resources, and embeds a suite of shared documents, calendars, and video-conferencing features. Clinical data are recorded in relation to molecular EV attributes and may be tagged with terms drawn from a network of externally maintained ontologies thus offering expansion of the system as the field matures. We fashioned the graphical user interface (GUI) around a web-based data visualization package. This system is now in an early stage of deployment, mainly focused on specimen tracking and clinical, laboratory, and imaging data capture in support of studies to optimize detection and analysis of brain tumour-specific mutations. It currently includes 4,392 specimens drawn from 611 subjects, the majority with brain tumours. As EV science evolves, we plan biorepository changes which may reflect multi-institutional collaborations, proteomic interfaces, additional biofluids, changes in operating procedures and kits for specimen handling, novel procedures for detection of tumour-specific EVs, and for RNA extraction and changes in the taxonomy of EVs. We have used an ontology-driven data model and web-based architecture with a graph theory-driven GUI to accommodate and stimulate the semantic web of EV science.
Zhang, Rui; Schweizer, Kenneth S
2012-04-21
We generalize the microscopic naïve mode coupling and nonlinear Langevin equation theories of the coupled translation-rotation dynamics of dense suspensions of uniaxial colloids to treat the effect of applied stress on shear elasticity, cooperative cage escape, structural relaxation, and dynamic and static yielding. The key concept is a stress-dependent dynamic free energy surface that quantifies the center-of-mass force and torque on a moving colloid. The consequences of variable particle aspect ratio and volume fraction, and the role of plastic versus double glasses, are established in the context of dense, glass-forming suspensions of hard-core dicolloids. For low aspect ratios, the theory provides a microscopic basis for the recently observed phenomenon of double yielding as a consequence of stress-driven sequential unlocking of caging constraints via reduction of the distinct entropic barriers associated with the rotational and translational degrees of freedom. The existence, and breadth in volume fraction, of the double yielding phenomena is predicted to generally depend on both the degree of particle anisotropy and experimental probing frequency, and as a consequence typically occurs only over a window of (high) volume fractions where there is strong decoupling of rotational and translational activated relaxation. At high enough concentrations, a return to single yielding is predicted. For large aspect ratio dicolloids, rotation and translation are always strongly coupled in the activated barrier hopping event, and hence for all stresses only a single yielding process is predicted.
Parízek, J; Mĕrićka, P; Nĕmecek, S; Nĕmecková, J; Zemánková, M; Sercl, M; Häringová, M
1996-03-01
Three children with primary intranasal encephalomeningocele associated with cerebrospinal fluid rhinorrhea were operated on at the Department of Neurosurgery, Hradec Králové. In two children, aged 4 and 9.5 years, freeze-dried allogeneic costal cartilage was glued into the skull base defect. This plugging was covered up with deep frozen allogeneic fascia lata. In the third child, an only 1-year-old boy, after transection of the neck of the encephalomeningocele freeze-dried allogeneic dura mater was glued on extradurally and deep-frozen allogeneic fascia lata applied intradurally. The cerebrospinal fluid rhinorrhea ceased immediately after surgery. Spontaneous atrophy of the intranasal portion of the encephalomeningocele was demonstrated respectively 11, 1, and 7 years postoperatively on computed tomography. To evaluate cartilage healing histologically, the extracted allogeneic cartilage used for orbital roof plasty after 4 months was examined. The extent of spotty regressions represented about 7% of the tissue volume. It is stressed that, once diagnosed, intranasal encephalomeningocele associated with cerebrospinal fluid rhinorrhea should be operated on for prevention of meningitis as soon as possible. PMID:8697455
Shaggy Photoreceptors with Subfoveal Fluid Associated with a Distant Choroidal Melanoma
Directory of Open Access Journals (Sweden)
Ann Q. Tran
2015-01-01
Full Text Available Purpose. To describe the enhanced depth imaging optical coherence tomography (EDI-OCT findings in a patient with an extra macula choroidal melanoma before and after treatment. Methods. Observational case report. Results. A 45 year-old Caucasian male patient was referred to retina clinic for management of choroidal melanoma. Examination revealed a nasal choroidal melanoma while EDI-OCT illustrated subfoveal fluid pocket with elongated shaggy photoreceptors distant and separate from the tumor. The patient was treated with plaque brachytherapy and intravitreal bevacizumab. One week after plaque removal, there was a dramatic reduction in the shaggy photoreceptors. Conclusion. Choroidal melanomas have effects that are not localized to the area of the tumor. This loculated pocket of subretinal fluid and coinciding changes to photoreceptor morphology may be related to global changes in choroidal function or release of tumor related cytokines.
Cohen, Philip R; Arfa, Kenneth S.
2016-01-01
Background: Ferrofluid is a colloidal suspension that usually consists of surfactant-coated nanoparticles of magnetite (Fe3O4) in a carrier liquid. Ferromagnetic fluid forms spikes when the liquid is exposed to a magnetic field. Purpose: The authors describe a man who developed temporary discoloration of his right palm and fingers after accidental cutaneous contact with ferrofluid and discuss some of the current and potential applications of this unique liquid. Methods: A 28-year-old man was ...
Sobkowicz, H M; Holy, J; Scott, G L
1990-07-01
The intercalated body is a newly discovered organelle in the inner and outer spiral sulcus cells of the mouse organ of Corti. The organelle was found in the cochleas of 14-day and older intact mice and in organs in culture of corresponding ages. The organelle consists of a stack of interconnected cisternae of endoplasmic reticulum and of membrane bound rodlets that are intercalated between, and run parallel to, the cisternae. The cisternal membranes are predominantly smooth, but some may display ribosomes. Most rodlets are from 1 to 2 microns long, about 0.1 micron wide, and contain electron dense material. Mitochondria are commonly associated with or incorporated into the organelle. Some electron micrographs suggest that the rodlets may originate from modified mitochondria. It is our impression that the formation of the organelle begins with the apposition of cisternae and mitochondria. Cisternal-associated mitochondria appear to constrict, elongate, and lose their inner membranes. In both the intact animal and in culture, the cells of the inner and outer spiral sulci display microvilli, apical junctional complexes, lateral intercellular spaces containing interdigitating cell processes, and appear to be involved in fluid formation. Moreover, in culture, the cells of inner and outer spiral sulci as well as some cells proliferating in the outgrowth zone participate in fluid formation, producing large fluid pockets. All these cells commonly contain intercalated bodies. It is possible that in the intact animal, as in culture, intercalated bodies may play a role in fluid regulation in the immediate vicinity of the hair cells. PMID:2374037
Directory of Open Access Journals (Sweden)
Hui Mao
2015-02-01
Full Text Available Micro-nano-based drilling fluid has attracted a strong interest due to its attractive properties, and micro-nano composite materials have great potential for developing intelligent drilling fluid. In this study a novel hydrophobic associated polymer based nano-silica composite with core–shell structure was prepared and characterized by PSD, SEM, TEM and ESEM. The results showed that the composite, as a micro-nano drilling fluid additive, possessed excellent properties such as thermal stability, rheology, fluid loss and lubricity. Especially, it could plug the formation effectively and improve the pressure bearing capability of formation significantly.
Schertzer, D.; Falgarone, E.
1996-01-01
1 Facts about the Workshop This workshop was convened on November 13-15 1995 by E. Falgarone and D. Schertzer within the framework of the Groupe de Recherche Mecanique des Fluides Geophysiques et Astrophysiques (GdR MFGA, Research Group of Geophysical and Astrophysical Fluid Mechanics) of Centre National de la Recherche Scientifique (CNRS, (French) National Center for Scientific Research). This Research Group is chaired by A. Babiano and the meeting was held at Ecole Normale Superieure, Paris...
Schertzer, D.; Falgarone, E.
1996-01-01
International audience 1 Facts about the Workshop This workshop was convened on November 13-15 1995 by E. Falgarone and D. Schertzer within the framework of the Groupe de Recherche Mecanique des Fluides Geophysiques et Astrophysiques (GdR MFGA, Research Group of Geophysical and Astrophysical Fluid Mechanics) of Centre National de la Recherche Scientifique (CNRS, (French) National Center for Scientific Research). This Research Group is chaired by A. Babiano and the meeting was held at Ecole...
Institute of Scientific and Technical Information of China (English)
Hun; Yong; SHIN; Hwayong; KIM; 等
2002-01-01
Quantitative representation of complicated behavior of fluid mixtures in the critical region by any of equation-of-state theories remains as a difficults thermodynamic topics to date.In the present work,a computational efforts were made for representing various types of critical loci of binary water with hydrocarbon systems showing Type Ⅱ and Type Ⅲ phase behavior by an elementary equation of state[called multi-fluid nonrandom lattice fluid EOS(MF-NLF EOS)]based on the lattice statistical mechanical theory.The model EOS requires two molecular parameters which representing molecular size and interaction energy for a pure component and single adjustable interaction energy parameter for binary mixtures.Critical temperature and pressure data were used to obtain molecular size parameter and vapor pressure data were used to obtain interaction energy parameter.The MF-NLF EOS model adapted in the present study correlated quantitatively well the critical loci of various binary water with hydrocarbon systems.
Tsiklauri, D
2001-01-01
It is known that a boundary slip velocity starts to play important role when the length scale over which the fluid velocity changes approaches the slip length, i.e. when the fluid is highly confined, for example, fluid flow through porous rock or blood vessel capillaries. Craig et al. [Phys. Rev. Lett., 87, 054504 (2001)] have recently experimentally established existence of a boundary slip in a Newtonian liquid. We investigate the effect of introduction of the boundary slip into the theory of propagation of elastic waves in a fluid-saturated porous medium formulated by Biot [J. Acoust. Soc. Am., 28, 179 (1956)]. Namely, we study the effect of introduction of boundary slip upon the function F(kappa) that measures the deviation from Poiseuille flow friction as a function of frequency parameter kappa. We found substantial deviations, especially in the asymptotical limit of high frequencies, in the behavior of F(kappa) with the incorporation of the boundary slip into the model. It is known that F(kappa) cruciall...
Evaluation of feasibility of measuring EHD film thickness associated with cryogenic fluids
Kannel, J. W.; Merriman, T. L.; Stockwell, R. D.; Dufrane, K. F.
1983-08-01
The feasibility of measuring elastohydrodynamic (EHD) films as formed with a cryogenic (LN2) fluid is evaluated. Modifications were made to an existing twin disk EHD apparatus to allow for disk lubrication with liquid nitrogen. This disk apparatus is equipped with an X-ray system for measuring the thickness of any lubricant film that is formed between the disks. Several film thickness experiments were conducted with the apparatus which indicate that good lubrication films are filmed with LN2. In addition to the film thickness studies, failure analyses of three bearings were conducted. The HPOTP turbine end bearings had experienced axial loads of 36,000 to 44,000 N (8,000 to 10,000 lb). High continuous radial loads were also experienced, which were most likely caused by thermal growth of the inner race. The resulting high internal loads caused race spalling and ball wear to occur.
Kharaka, Yousif K.; Thordsen, James J.; Evans, William C.; Kennedy, B. Mack
1999-01-01
18O values establish that waters are predominantly of meteoric origin. The chemical compositions of water and gases are controlled mainly by the ambient rock types, and chemical geothermometry gives reservoir temperatures of 80-150 degrees C indicating shallow to moderate circulation depths of up to 6 km. However, compositions and isotope abundances of noble gases and delta 13C values of HCO3 indicate a significant (up to 50%) mantle component for the volatiles. The relatively high fluxes of CO2 (C/ 3He nearly equal 10 10) and other volatiles of mantle origin support a deep continuous flow model, especially at depths >6 km. Numerical simulations indicate that these high fluxes of CO2 of mantle and deep crustal origin are sufficient to generate lithostatic fluid pressures, and thus a weakened fault, in time scales comparable to those of earthquake cycles.
Association of Brucella Meningoencephalitis with Cerebrospinal Fluid Shunt in A Child: A Case Report
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Babak ABDINIA
2013-01-01
Full Text Available Brucellosis is an endemic zoonosis in Iran. It is a systemic infection that can involve any organs or systems of the body and have variable presentations. Ventriculoperitoneal (VP shunt infections due to brucellosis have been rarely reported in the literatures.This is the history of a four years old boy who developed Brucella meningoencephalitis at the age of 42 months, whilst he had a VP shunt in situ for hydrocephalus treatment. Also, he presented brucellosis as acute abdomen. This patient was treated with trimethoprim-sulfamethoxazole, gentamicin and rifampicin. The shunt was extracted and all clinical and laboratory test abnormalities subsided through this management.We propose that in a patient with Brucella meningoencephalitis, the cerebrospinal fluid shunt system can be extracted and treatment with appropriate combination of antibiotics could be successful. Moreover, it shows that brucellosis should be considered in the differential diagnosis for acute abdomen and ascites in endemic regions.
Genome-wide association study of NMDA receptor coagonists in human cerebrospinal fluid and plasma
Luykx, J. J.; Bakker, S. C.; Visser, W. F.; Verhoeven-Duif, N.; Buizer-Voskamp, J. E.; den Heijer, J. M.; Boks, M. P M; Sul, J. H.; Eskin, E.; Ori, A. P.; Cantor, R. M.; Vorstman, J.; Strengman, E.; DeYoung, J.; Kappen, T. H.; Pariama, E.; van Dongen, E. P A; Borgdorff, P.; Bruins, P.; de Koning, T. J.; Kahn, R. S.; Ophoff, R. A.
2015-01-01
The N-methyl-d-aspartate receptor (NMDAR) coagonists glycine, d-serine and l-proline play crucial roles in NMDAR-dependent neurotransmission and are associated with a range of neuropsychiatric disorders. We conducted the first genome-wide association study of concentrations of these coagonists and t
International Nuclear Information System (INIS)
Electro-thermal vibration of the double of Boron Nitride nanotubes (BNNTs) which are coupled by visco-Pasternak medium is carried out based on strain gradient theory. Two BNNTs are placed in uniform temperature and electric fields, the latter being applied through attached electrodes at both ends. Moreover, one of the BNNT is under conveying fluid. Considering Euler-Bernoulli beam (EBB) model and Knudsen number, the higher-order equations of motion are derived base on the Hamilton's principle where differential quadrature method (DQM) is applied to obtain the frequency of coupled BNNTs system. The detailed parametric study is conducted, focusing on the combined effects of the Knudsen number, aspect ratio, thermal and electric fields, velocity of conveying fluid and visco-Pasternak coefficients on the stability of coupled system. Also, it is found that trend of figures have good agreement with the other studies
Choquard, Philippe
2013-01-01
The coupling between dilatation and vorticity, two coexisting and fundamental processes in fluid dynamics is investigated here, in the simplest cases of inviscid 2D isotropic Burgers and pressureless Euler-Coriolis fluids respectively modeled by single vortices confined in compressible, local, inertial and global, rotating, environments. The field equations are established, inductively, starting from the equations of the characteristics solved with an initial Helmholtz decomposition of the velocity fields namely a vorticity free and a divergence free part and, deductively, by means of a canonical Hamiltonian Clebsch like formalism, implying two pairs of conjugate variables. Two vector valued fields are constants of the motion: the velocity field in the Burgers case and the momentum field per unit mass in the Euler-Coriolis one. Taking advantage of this property, a class of solutions for the mass densities of the fluids is given by the Jacobian of their sum with respect to the actual coordinates. Implementatio...
Jamali, Safa; Boromand, Arman; Khani, Shaghayegh; Wagner, Jacob; Yamanoi, Mikio; Maia, Joao
2015-04-01
In this work, a generalized relation between the fluid compressibility, the Flory-Huggins interaction parameter (χ), and the simulation parameters in multi-body dissipative particle dynamics (MDPD) is established. This required revisiting the MDPD equation of state previously reported in the literature and developing general relationships between the parameters used in the MDPD model. We derive a relationship to the Flory-Huggins χ parameter for incompressible fluids similar to the work previously done in dissipative particle dynamics by Groot and Warren. The accuracy of this relationship is evaluated using phase separation in small molecules and the solubility of polymers in dilute solvent solutions via monitoring the scaling of the radius of gyration (Rg) for different solvent qualities. Finally, the dynamics of the MDPD fluid is studied with respect to the diffusion coefficient and the zero shear viscosity.
Hardin, G. R.; Sani, R. L.; Henry, D.; Roux, B.
1990-01-01
The buoyancy-driven instability of a monocomponent or binary fluid completely contained in a vertical circular cylinder is investigated, including the influence of the Soret effect for the binary mixture. The Boussinesq approximation is used, and the resulting linear stability problem is solved using a Galerkin technique. The analysis considers fluid mixtures ranging from gases to liquid metals. The flow structure is found to depend strongly on both the cylinder aspect ratio and the magnitude of the Soret effect. The predicted stability limits are shown to agree closely with experimental observations.
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Vinš Václav
2014-03-01
Full Text Available The density gradient theory (GT combined with a SAFT-type (Statistical Associating Fluid Theory equation of state has been used for modeling the surface tension of associating fluids represented by a series of six alkanols ranging from methanol to 1-pentanol. The effect of nonzero dipole moment of the selected alkanols on the predicted surface tension was investigated in this study. Results of the GT + non-polar Perturbed Chain (PC SAFT equation of state were compared to predictions of GT combined with the PC-polar-SAFT, i.e. PCP-SAFT, equation. Both GT + PC-SAFT and GT + PCP-SAFT give reasonable prediction of the surface tension for pure alkanols. Results of both models are comparable as no significant difference in the modeled saturation properties and in the predicted surface tension using GT was found. Consideration of dipolar molecules of selected alkanols using PCP-SAFT had only minor effect on the predicted properties compared to the non-polar PC-SAFT model.
Enomoto, Masaki; Nakagawa, Satoshi; Sawabe, Tomoo
2012-01-01
Marine invertebrates interact with various microorganisms ranging from pathogens to symbionts. One-to-one symbiosis between a single microbial species and a single host animal has served as a model for the study of host-microbe interactions. In addition, increasing attention has recently been focused on the complex symbiotic associations, e.g., associations between sponges and their symbionts, due to their biotechnological potential; however, relatively little is known about the microbial div...
Njoku, Chinedu J.; Saville, William J. A.; Reed, Stephen M.; Oglesbee, Michael J.; Rajala-Schultz, Päivi J.; Stich, Roger W
2002-01-01
Equine protozoal myeloencephalitis (EPM) is a disease of horses that is primarily associated with infection with the apicomplexan Sarcocystis neurona. Infection with this parasite alone is not sufficient to induce the disease, and the mechanism of neuropathogenesis associated with EPM has not been reported. Nitric oxide (NO) functions as a neurotransmitter, a vasodilator, and an immune effector and is produced in response to several parasitic protozoa. The purpose of this work was to determin...
Safonov, O.; Butvina, V.
2009-04-01
Relics of potassium-rich (4-14 wt. % of K2O and K2O/Na2O > 1.0) melts are a specific features of some partially molten diamondiferous eclogite xenoliths in kimberlites worldwide [1, 2]. In addition, potassic silicic melt inclusions with up to 16 wt. % of K2O are associated with eclogite phases in kimberlitic diamonds (O. Navon, pers. comm.). According to available experimental data, no such potassium contents can be reached by "dry" and hydrous melting of eclogite. These data point to close connection between infiltration of essentially potassic fluids, partial melting and diamond formation in mantle eclogites [2]. Among specific components of these fluids, alkali chlorides, apparently, play an important role. This conclusion follows from assemblages of the melt relics with chlorine-bearing phases in eclogite xenoliths [1], findings of KCl-rich inclusions in diamonds from the xenoliths [3], and concentration of Cl up to 0.5-1.5 wt. % in the melt inclusions in diamonds. In this presentation, we review our experimental data on reactions of KCl melts and KCl-bearing fluids with model and natural eclogite-related minerals and assemblages. Experiments in the model system jadeite(±diopside)-KCl(±H2O) at 4-7 GPa showed that, being immiscible, chloride liquids provoke a strong K-Na exchange with silicates (jadeite). As a result, low-temperature ultrapotassic chlorine-bearing (up to 3 wt. % of Cl) aluminosilicate melts form. These melts is able to produce sanidine, which is characteristic phase in some partially molten eclogites. In addition, in presence of water Si-rich Cl-bearing mica (Al-celadonite-phlogopite) crystallizes in equilibrium with sanidine and/or potassic melt and immiscible chloride liquid. This mica is similar to that observed in some eclogitic diamonds bearing chloride-rich fluid inclusions [4], as well as in diamonds in partially molten eclogites [2]. Interaction of KCl melt with pyrope garnet also produce potassic aluminosilicate melt because of high
Institute of Scientific and Technical Information of China (English)
吴畏; 陆九芳; 付东; 刘金晨; 李以圭
2004-01-01
The density functional theory, simplified by the local density approximation and mean-field approximation, is applied to study the surface properties of pure non-polar fluids. A reasonable long rang correction is adopted to avoid the truncation of the potential. The perturbation theory is applied to establish the equation for the phase equilibrium, in which the hard-core chain fluid is as the reference fluid and the Yukawa potential is used as the perturbation term. Three parameters, ε/k, d and ms, are regressed from the vapor-liquid equilibria, and the surface properties, including density profile, surface tension and local surface tension profile are predicted with these parameters.
Results from the Gardner-Derrida-Mottishaw theory of associative memory.
Koyama, Hideyuki; Fujie, Norio; Seyama, Hiroyuki
1999-03-01
General computable formulas for overlap and the other parameters are derived from the Gardner-Derrida-Mottishaw theory of associative memory on the Little-Hopfield model. The overlap is expressed in terms of integral of many-dimensional Gaussian functions. A method of approximation is developed to make numerical computation easy. It is shown that the numerical results are totally in good agreement with simulation. PMID:12662701
Behavior of boundary string field theory associated with integrable massless flow.
Fujii, A; Itoyama, H
2001-06-01
We put forward an idea that the boundary entropy associated with integrable massless flow of thermodynamic Bethe ansatz (TBA) is identified with tachyon action of boundary string field theory. We show that the temperature parametrizing a massless flow in the TBA formalism can be identified with tachyon energy for the classical action at least near the ultraviolet fixed point, i.e., the open string vacuum.
Nold, Andreas; Goddard, Benjamin D; Kalliadasis, Serafim
2014-01-01
We examine the nanoscale behavior of an equilibrium three-phase contact line in the presence of long-ranged intermolecular forces by employing a statistical mechanics of fluids approach, namely density functional theory (DFT) together with fundamental measure theory (FMT). This enables us to evaluate the predictive quality of effective Hamiltonian models in the vicinity of the contact line. In particular, we compare the results for mean field effective Hamiltonians with disjoining pressures defined through (I) the adsorption isotherm for a planar liquid film, and (II) the normal force balance at the contact line. We find that the height profile obtained using (I) shows good agreement with the adsorption film thickness of the DFT-FMT equilibrium density profile in terms of maximal curvature and the behavior at large film heights. In contrast, we observe that while the height profile obtained by using (II) satisfies basic sum rules, it shows little agreement with the adsorption film thickness of the DFT results...
Sporer, B; Koedel, U; Paul, R; Eberle, J; Arendt, G; Pfister, H-W
2004-02-01
Vascular endothelial growth factor (VEGF) is a potent angiogenic and mitogenic peptide, which also induces several mediators that may play a role in HIV induced CNS damage. VEGF levels were determined in cerebrospinal fluid (CSF) and serum samples from patients with (n = 8) and without (n = 19) directly HIV associated CNS disorders and HIV negative control patients (n = 18). VEGF serum but not CSF levels were significantly increased in HIV infected patients with (381.1 (78.9) pg/ml) HIV associated CNS diseases compared with those without (120.8 (13.1) pg/ml) and HIV negative control patients (133.1(14.8) pg/ml). Serum samples from patients with untreated HIV associated encephalopathy (HIVE, n = 3) contained the highest VEGF levels (583.9 (71.5) pg/ml). In two patients VEGF serum levels were reduced during antiretroviral therapy. However, regardless of effective viral suppression, patients with HIVE still had higher levels compared with HIV infected patients without HIVE. A relevant increase of serum VEGF was not observed in patients without HIVE though high HI viral load. We conclude that HIVE is associated with increased serum VEGF levels. Further studies are warranted to elucidate the role of VEGF in HIVE. PMID:14742610
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Bharti AR
2016-04-01
Full Text Available Ajay R Bharti,1 Steven Paul Woods,2 Ronald J Ellis,3 Mariana Cherner,2 Debra Rosario,3 Michael Potter,3 Robert K Heaton,2 Ian P Everall,4 Eliezer Masliah,5 Igor Grant,2 Scott L Letendre1 On behalf of the Translational Methamphetamine AIDS Research Center Group 1Department of Medicine, 2Department of Psychiatry, 3Department of Neurosciences, University of California San Diego, San Diego, CA, USA; 4Department of Psychiatry, University of Melbourne, Victoria, Australia; 5Department of Pathology, University of Californa San Diego, San Diego, CA, USA Background: Human immunodeficiency virus (HIV and methamphetamine use commonly affect neurocognitive (NC functioning. We evaluated the relationships between NC functioning and two fibroblast growth factors (FGFs in volunteers who differed in HIV serostatus and methamphetamine dependence (MAD. Methods: A total of 100 volunteers were categorized into four groups based on HIV serostatus and MAD in the prior year. FGF-1 and FGF-2 were measured in cerebrospinal fluid by enzyme-linked immunosorbent assays along with two reference biomarkers (monocyte chemotactic protein [MCP]-1 and neopterin. Comprehensive NC testing was summarized by global and domain impairment ratings. Results: Sixty-three volunteers were HIV+ and 59 had a history of MAD. FGF-1, FGF-2, and both reference biomarkers differed by HIV and MAD status. For example, FGF-1 levels were lower in subjects who had either HIV or MAD than in HIV– and MAD– controls (P=0.003. Multivariable regression identified that global NC impairment was associated with an interaction between FGF-1 and FGF-2 (model R2=0.09, P=0.01: higher FGF-2 levels were only associated with neurocognitive impairment among subjects who had lower FGF-1 levels. Including other covariates in the model (including antidepressant use strengthened the model (model R2=0.18, P=0.004 but did not weaken the association with FGF-1 and FGF-2. Lower FGF-1 levels were associated with impairment
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Irina Tasevska
2014-01-01
Full Text Available This study investigated if copeptin is affected by high salt intake and whether any salt-induced changes in copeptin are related to the degree of salt sensitivity. The study was performed on 20 men and 19 women. In addition to meals containing 50 mmol NaCl daily, capsules containing 100 mmol NaCl and corresponding placebo capsules were administered during 4 weeks each, in random order. Measurements of 24 h blood pressure, body weight, 24 h urinary volume, and fasting plasma copeptin were performed at high and low salt consumption. Copeptin increased after a high compared to low dietary salt consumption in all subjects 3,59 ± 2,28 versus 3,12 ± 1,95 (P = 0,02. Copeptin correlated inversely with urinary volume, at both low (r = −0,42; P = 0,001 and high (r = −0,60; P < 0,001 salt consumption, as well as with the change in body weight (r = −0,53; P < 0,001. Systolic salt sensitivity was inversely correlated with salt-induced changes of copeptin, only in females (r = −0,58; P = 0,017. As suppression of copeptin on high versus low salt intake was associated with systolic salt sensitivity in women, our data suggest that high fluid intake and fluid retention may contribute to salt sensitivity.
Institute of Scientific and Technical Information of China (English)
Ying-hui CHEN; Cui-cui WANG; Xia XIAO; Li WEI; Guoxiong XU
2013-01-01
Aim:To investigate whether multidrug resistance-associated protein 1 (MRP1) was responsible for drug resistence in refractory epilepsy in amygdale kindling rats.Methods:Rat amygdale kindling was used as a model of refractory epilepsy.The expression of MRP1 mRNA and protein in the brains was examined using RT-PCR and Western blot.MRP1-positive cells in the cortex and hippocampus were studied with immunohistochemical staining.The rats were intraperitoneally injected with phenytoin (50 mg/kg) or carbamazepine (20 mg/kg),and their concentrations in the cortical extracellular fluid were measured using microdialysis and HPLC.Probenecid,a MRP1 inhibitor (40 mmol/L,50 μL) was administered through an inflow tube into the cortex 30 min before injection of the antiepileptic drugs.Results:The expression of MRP1 mRNA and protein was significantly up-regulated in the cortex and hippocampus in amygdale kindling rats compared with the control group.Furthermore,the number of MRP1-positive cells in the cortex and hippocampus was also significantly increased in amygdale kindling rats.Microdialysis studies showed that the concentrations of phenytoin and carbamazepine in the cortical extracellular fluid were significantly decreased in amygdale kindling rats.Pre-administration of probenecid could restore the concentrations back to their control levels.Conclusion:Up-regulation of MRP1 is responsible for the resistance of brain cells to antiepileptic drugs in the amygdale kindling rats.
Kushnir, Mark M; Naessén, Tord; Wanggren, Kjell; Hreinsson, Julius; Rockwood, Alan L; Meikle, A Wayne; Bergquist, Jonas
2016-09-01
Steroid concentrations in stimulated follicular fluid (sFF) samples have been linked to the quality of oocytes used in IVF treatments. Most of the published studies focused on evaluating the association of the IVF outcomes with only a few of the steroids, measured by immunoassays (IA). We performed a treatment outcome, prospective cohort study using stimulated FF sampled from 14 infertile women undergoing IVF treatment; single oocyte was used per IVF cycle. Fourteen endogenous steroids were analyzed in 22 ovarian follicle aspirations, which corresponded to the embryos used in the IVF. Ten oocytes were associated with live birth (LB) and 12 with no pregnancy (NP). Steroids were analyzed using liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods. Differences in distribution of concentrations in association with the pregnancy outcome (LB or NP), and receiver operating characteristic (ROC) curves analysis were performed for the entire cohort and for within-women data. The predominant androgen and estrogen in stimulated sFF were androstenedione (A4) and estradiol (E2), respectively. Lower concentrations of pregnenolone (Pr), lower ratios of A4/ dehydroepiandrosterone (DHEA), testosterone (Te)/DHEA, and greater ratios of E2/Te, and estrone/A4 were observed in sFF samples associated with LB. Among the oocytes associated with NP, in four out of 12 samples total concentration of androgens was above the distribution of the concentrations in the oocytes corresponding to the LB group. Observations of the study indicated increased consumption of precursors and increased biosynthesis of estrogens in the follicles associated with LB. Our data suggest that potentially steroid profiles in sFF obtained during oocyte retrieval may serve as biomarkers for selection of the best embryo to transfer after IVF. PMID:26388251
Kushnir, Mark M; Naessén, Tord; Wanggren, Kjell; Hreinsson, Julius; Rockwood, Alan L; Meikle, A Wayne; Bergquist, Jonas
2016-09-01
Steroid concentrations in stimulated follicular fluid (sFF) samples have been linked to the quality of oocytes used in IVF treatments. Most of the published studies focused on evaluating the association of the IVF outcomes with only a few of the steroids, measured by immunoassays (IA). We performed a treatment outcome, prospective cohort study using stimulated FF sampled from 14 infertile women undergoing IVF treatment; single oocyte was used per IVF cycle. Fourteen endogenous steroids were analyzed in 22 ovarian follicle aspirations, which corresponded to the embryos used in the IVF. Ten oocytes were associated with live birth (LB) and 12 with no pregnancy (NP). Steroids were analyzed using liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods. Differences in distribution of concentrations in association with the pregnancy outcome (LB or NP), and receiver operating characteristic (ROC) curves analysis were performed for the entire cohort and for within-women data. The predominant androgen and estrogen in stimulated sFF were androstenedione (A4) and estradiol (E2), respectively. Lower concentrations of pregnenolone (Pr), lower ratios of A4/ dehydroepiandrosterone (DHEA), testosterone (Te)/DHEA, and greater ratios of E2/Te, and estrone/A4 were observed in sFF samples associated with LB. Among the oocytes associated with NP, in four out of 12 samples total concentration of androgens was above the distribution of the concentrations in the oocytes corresponding to the LB group. Observations of the study indicated increased consumption of precursors and increased biosynthesis of estrogens in the follicles associated with LB. Our data suggest that potentially steroid profiles in sFF obtained during oocyte retrieval may serve as biomarkers for selection of the best embryo to transfer after IVF.
Directory of Open Access Journals (Sweden)
Ying Liu
Full Text Available Recently, a large meta-analysis of five genome wide association studies (GWAS identified a novel locus (rs2718058 adjacent to NME8 that played a preventive role in Alzheimer's disease (AD. However, this link between the single nucleotide polymorphism (SNP rs2718058 and the pathology of AD have not been mentioned yet. Therefore, this study assessed the strength of association between the NME8 rs2718058 genotypes and AD-related measures including the cerebrospinal fluid (CSF amyloid beta, tau, P-tau concentrations, neuroimaging biomarkers and cognitive performance, in a large cohort from Alzheimer's Disease Neuroimaging Initiative (ADNI database. We used information of a total of 719 individuals, including 211 normal cognition (NC, 346 mild cognitive impairment (MCI and 162 AD. Although we didn't observe a positive relationship between rs2718058 and AD, it was significantly associated with several AD related endophenotypes. Among the normal cognitively normal participants, the minor allele G carriers showed significantly associated with higher CDRSB score than A allele carriers (P = 0.021. Occipital gyrus atrophy were significantly associated with NME8 genotype status (P = 0.002, with A allele carriers has more atrophy than the minor allele G carriers in AD patients; lateral ventricle (both right and left cerebral metabolic rate for glucose (CMRgl were significantly associated with NME8 genotype (P < 0.05, with GA genotype had higher metabolism than GG and AA genotypes in MCI group; the atrophic right hippocampus in 18 months is significantly different between the three group, with GG and AA genotypes had more hippocampus atrophy than GA genotypes in the whole group. Together, our results are consistent with the direction of previous research, suggesting that NME8 rs2718058 appears to play a role in lowering the brain neurodegeneration.
Institute of Scientific and Technical Information of China (English)
WANG HaiJun; GU Fang; HONG XiaoZhong; BA XinWu
2007-01-01
The equation of the state of the hydrogen bonding fluid system of AaDd type is studied by the principle of statistical mechanics. The influences of hydrogen bonds on the equation of state of the system are obtained based on the change in volume due to hydrogen bonds. Moreover, the number density fluctuations of both molecules and hydrogen bonds as well as their spatial correlation property are investigated. Furthermore, an equation describing relation between the number density correlation function of "molecules-hydrogen bonds" and that of molecules and hydrogen bonds is derived. As application,taking the van der Waals hydrogen bonding fluid as an example, we considered the effect of hydrogen bonds on its relevant statistical properties.
Sørig, Simon A.; Clausen, Ole R.; Andresen, Katrine J.
2016-04-01
The western part of the Norwegian-Danish Basin is part of the Northern Permian Basin and encompasses a variety of Zechstein salt structures (pillows, rollers, diapirs and salt walls). The area has been studied for decades with respect to HC prospectively associated to salt structures as well a focus area for studies on conceptual evolution of salt structures and faults associated with the salt structures. Previous local studies on fluid migration and Direct Hydrocarbon Indicators (DHI's) in the area show a close relation between halo kinetics and local fluid migration. In the present study we have used3D seismic data (approximately 3500 km2) to identify and describe A: large diapirs which have been active until the youngest Cenozoic, B: medium sized diapirs being active until the early Cenozoic, C: salt relicts creating small non active pillows, and D: small satellite structures related to type A. The salt structures are evenly distributed across the studied area, and we conclude that the structures were initiated during the late Triassic due to depositional controlled differential loading combined with differential subsidence. DHI's are identified at various stratigraphic and structural settings associated to the salt structures and each structure type has different types of DHI's associated. The DHIs observed at the type A and B diapirs are located above or at the stem of the diapirs and are here interpreted as classic structural hydrocarbon traps associated with rising salt deforming the strata. However, the DHI's associated to type C salt pillows have a relatively small lateral extent, stratigraphically restricted to the Mesozoic succession; they are located above the apex of the pillow and have in general a seismically disturbed zone located beneath the DHI. The seismically disturbed zone resembles gas chimneys, but may also be related to minor deformation of the Mesozoic strata overlying the type C pillows. A biogenic origin of the gas in at least some of the
Energy Technology Data Exchange (ETDEWEB)
Vasco, D.W.; Rucci, A.; Ferretti, A.; Novali, F.; Bissell, R.; Ringrose, P.; Mathieson, A.; Wright, I.
2009-10-15
Interferometric Synthetic Aperture Radar (InSAR), gathered over the In Salah CO{sub 2} storage project in Algeria, provides an early indication that satellite-based geodetic methods can be effective in monitoring the geological storage of carbon dioxide. An injected volume of 3 million tons of carbon dioxide, from one of the first large-scale carbon sequestration efforts, produces a measurable surface displacement of approximately 5 mm/year. Using geophysical inverse techniques we are able to infer flow within the reservoir layer and within a seismically detected fracture/ fault zone intersecting the reservoir. We find that, if we use the best available elastic Earth model, the fluid flow need only occur in the vicinity of the reservoir layer. However, flow associated with the injection of the carbon dioxide does appear to extend several kilometers laterally within the reservoir, following the fracture/fault zone.
Energy Technology Data Exchange (ETDEWEB)
Uddin, M. J., E-mail: josim.phys2007@gmail.com; Alam, M. S.; Mamun, A. A. [Department of Physics, Jahangirnagar University, Savar, Dhaka 1342 (Bangladesh)
2015-06-15
A theoretical investigation is made on the positron-acoustic (PA) shock waves (SHWs) in an unmagnetized electron-positron-ion plasma containing immobile positive ions, cold mobile positrons, and hot positrons and electrons following the kappa (κ) distribution. The cold positron kinematic viscosity is taken into account, and the reductive perturbation method is used to derive the Burgers equation. It is found that the viscous force acting on cold mobile positron fluid is a source of dissipation and is responsible for the formation of the PA SHWs. It is also observed that the fundamental properties of the PA SHWs are significantly modified by the effects of different parameters associated with superthermal (κ distributed) hot positrons and electrons.
Butler, William E.; Atai, Nadia; Carter, Bob; Hochberg, Fred
2014-01-01
The Richard Floor Biorepository supports collaborative studies of extracellular vesicles (EVs) found in human fluids and tissue specimens. The current emphasis is on biomarkers for central nervous system neoplasms but its structure may serve as a template for collaborative EV translational studies in other fields. The informatic system provides specimen inventory tracking with bar codes assigned to specimens and containers and projects, is hosted on globalized cloud computing resources, and e...
Directory of Open Access Journals (Sweden)
Krishna Lal
1970-01-01
Full Text Available The motion of a power law fluid past a suddenly accelerated wall which moves with a constant velocity U (t parallel to the wall has been considered for the similarity analysis. Recently this problem has been discussed and two possible group of transformation have been used by T.Y. Na/sup 1/. In this paper the third possible transformation has been found. The variation of the wall velocity U (t with time, t, has been worked out.
Ebato, Yuki; Miyata, Tatsuhiko
2016-05-01
Ornstein-Zernike (OZ) integral equation theory is known to overestimate the excess internal energy, Uex, pressure through the virial route, Pv, and excess chemical potential, μex, for one-component Lennard-Jones (LJ) fluids under hypernetted chain (HNC) and Kovalenko-Hirata (KH) approximatons. As one of the bridge correction methods to improve the precision of these thermodynamic quantities, it was shown in our previous paper that the method to apparently adjust σ parameter in the LJ potential is effective [T. Miyata and Y. Ebato, J. Molec. Liquids. 217, 75 (2016)]. In our previous paper, we evaluated the actual variation in the σ parameter by using a fitting procedure to molecular dynamics (MD) results. In this article, we propose an alternative method to determine the actual variation in the σ parameter. The proposed method utilizes a condition that the virial and compressibility pressures coincide with each other. This method can correct OZ theory without a fitting procedure to MD results, and possesses characteristics of keeping a form of HNC and/or KH closure. We calculate the radial distribution function, pressure, excess internal energy, and excess chemical potential for one-component LJ fluids to check the performance of our proposed bridge function. We discuss the precision of these thermodynamic quantities by comparing with MD results. In addition, we also calculate a corrected gas-liquid coexistence curve based on a corrected KH-type closure and compare it with MD results.
Runchal, A. K.; Sagar, B.; Baca, R. G.; Kline, N. W.
1985-09-01
Postclosure performance assessment of the proposed high-level nuclear waste repository in flood basalts at Hanford requires that the processes of fluid flow, heat transfer, and mass transport be numerically modeled at appropriate space and time scales. A suite of computer models has been developed to meet this objective. The theory of one of these models, named PORFLO, is described in this report. Also presented are a discussion of the numerical techniques in the PORFLO computer code and a few computational test cases. Three two-dimensional equations, one each for fluid flow, heat transfer, and mass transport, are numerically solved in PORFLO. The governing equations are derived from the principle of conservation of mass, momentum, and energy in a stationary control volume that is assumed to contain a heterogeneous, anisotropic porous medium. Broad discrete features can be accommodated by specifying zones with distinct properties, or these can be included by defining an equivalent porous medium. The governing equations are parabolic differential equations that are coupled through time-varying parameters. Computational tests of the model are done by comparisons of simulation results with analytic solutions, with results from other independently developed numerical models, and with available laboratory and/or field data. In this report, in addition to the theory of the model, results from three test cases are discussed. A users' manual for the computer code resulting from this model has been prepared and is available as a separate document.
Theory and Modelling of Electrolytes and Chain Molecules
Li, Ming
2011-01-01
An aqueous solution of electrolytes can be modelled simplistically as charged hard spheresdispersed in a dielectric continuum. We review various classical theories for hard sphere systems including the Percus-Yevick theory, the mean spherical approximation, the Debye-Hückel theory and the hyper-netted chain theory, and we compare the predictions of the theories with simulation results. The statistical associating fluid theory (SAFT) has proved to be accurate for neutral polymers. It is mo...
Induced Seismicity Associated with Waste Fluid Injection into Deep Wells in Youngstown, Ohio
Kim, W.
2012-12-01
Since March 2011, residents in Youngstown, Ohio area experienced small earthquakes (M ~2.5). By 25 November 2011, about a dozen small but felt earthquakes have occurred around Youngstown. On 1 Dec. 2011 four portable seismographs were deployed around the epicentral area to monitor seismicity at close distances and determine hypocenters of the small earthquakes accurately, because these shocks were occurring close to a deep waste fluid injection well that began injection operation on 28 Dec. 2010. On 24 December 2011, a magnitude 2.7 shock occurred in the epicentral area which was accurately located by using the portable station data. The 24 Dec. shock is located about 800 m from the injection well and at a depth of 3.5 km, suggesting that those earthquakes in Youngstown could have been induced by the deep well injection operation. Hence, the injection was stopped on 30 Dec. 2011. However, the largest earthquake in the sequence (M4.0) occurred on 31 December 2011 within about 24 hours from halting injection operation. A total of 196 shocks are recorded during Dec. 2011 - April 2012. These shocks occurred as three distinct clusters of events, and a swarm of 82 small events. Three clusters of shocks have occurred in the narrow depth range (3.5-3.9 km) and the clusters appear to be on parallel faults of similar orientation offset by about 200-300 m apart. The swarm of small shocks (M -0.3 - 0.1) have occurred on 18 Feb. 2012 and lasted only few hours (12:36-15:46). These swarm events all lie in a very small region with depth range 3.8-4.2 km. The Precambrian basement rock in the region is at a depth 2.7 km, and hence all the shocks have occurred within in the Precambrian basement. Focal mechanism of the main shock is predominantly strike-slip faulting along steeply dipping nodal planes. The orientation of the WSW striking nodal plane (265 degree) is consistent with the lineation of the main cluster of shocks that include well-located main shock and other two largest
Kolaei, Amir; Rakheja, Subhash; Richard, Marc J.
2014-01-01
An analytical model is developed to study the transient lateral sloshing in horizontal cylindrical containers assuming inviscid, incompressible and irrotational flows. The model is derived by implementing the linearized free-surface boundary condition and bipolar coordinate transformation, resulting in a truncated system of linear ordinary differential equations, which is numerically solved to determine the fluid velocity potentials followed by the hydrodynamic forces and moment. The model results are compared with those obtained from the multimodal solution. The free-surface elevation and hydrodynamic coefficients are also compared with the reported experimental and analytical data as well as numerical simulations to establish validity of the model. The capability of the model for predicting non-resonant slosh is also evaluated using the critical free-surface amplitude. The model validity is further illustrated by comparing the transient liquid slosh responses of a partially filled tank subject to steady lateral acceleration characterizing a vehicle turning maneuver with those obtained from fully nonlinear CFD simulations and pendulum models. It is shown that the linear slosh model yields more accurate prediction of dynamic slosh than the pendulum models and it is significantly more computationally efficient than the nonlinear CFD model. The slosh model is subsequently applied to roll plane model of a suspended tank vehicle to study the effect of dynamic liquid slosh on steady-turning roll stability limit of the vehicle under constant and variable axle load conditions. The results suggest that the roll moment arising from the dynamic fluid slosh yields considerably lower roll stability limit of the partly-filled tank vehicle compared to that predicted from the widely reported quasi-static fluid slosh model.
DEFF Research Database (Denmark)
Herslund, Peter Jørgensen; Thomsen, Kaj; Abildskov, Jens;
2013-01-01
The complex fluid phase behaviour, of the binary system comprised of water and tetrahydrofuran (THF) is modelled by use of the cubic-plus-association (CPA) equation of state. A total of seven modelling approaches are analysed, differing only in their way of describing THF and its interactions...... (hydrogen bonding) with water.The qualitative behaviour of the fluid phase equilibria in this system can only be described by CPA when cross-association between water and THF is allowed.Six of the seven tested modelling scenarios allow for cross-association between the two compounds. These scenarios are...... named Case 2 to Case 7. Case 2 treats THF as non self-associating, but applies a single association site on the THF oxygen atom, that allows for cross-linking with a single water molecule. Case 3 is identical to Case 2 but applies two association sites on THF, allowing for simultaneous cross...
Directory of Open Access Journals (Sweden)
Sonia Molina-Pinelo
2012-01-01
Full Text Available The identification of new less invasive biomarkers is necessary to improve the detection and prognostic outcome of respiratory pathological processes. The measurement of miRNA expression through less invasive techniques such as plasma and serum have been suggested to analysis of several lung malignancies including lung cancer. These studies are assuming a common deregulated miRNA expression both in blood and lung tissue. The present study aimed to obtain miRNA representative signatures both in plasma and bronchoalveolar cell fraction that could serve as biomarker in respiratory diseases. Ten patients were evaluated to assess the expression levels of 381 miRNAs. We found that around 50% miRNAs were no detected in both plasma and bronchoalveolar cell fraction and only 20% of miRNAs showed similar expression in both samples. These results show a lack of association of miRNA signatures between plasma and bronchoalveolar cytology in the same patient. The profiles are not comparable; however, there is a similarity in the relative expression in a very small subset of miRNAs (miR-17, miR-19b, miR-195 and miR-20b between both biological samples in all patients. This finding supports that the miRNAs profiles obtained from different biological samples have to be carefully validated to link with respiratory diseases.
Directory of Open Access Journals (Sweden)
Diego M Morales
Full Text Available Neurological outcomes of preterm infants with post-hemorrhagic hydrocephalus (PHH remain among the worst in infancy, yet there remain few instruments to inform the treatment of PHH. We previously observed PHH-associated elevations in cerebrospinal fluid (CSF amyloid precursor protein (APP, neural cell adhesion molecule-L1 (L1CAM, neural cell adhesion molecule-1 (NCAM-1, and other protein mediators of neurodevelopment.The objective of this study was to examine the association of CSF APP, L1CAM, and NCAM-1 with ventricular size as an early step toward developing CSF markers of PHH.CSF levels of APP, L1CAM, NCAM-1, and total protein (TP were measured in 12 preterm infants undergoing PHH treatment. Ventricular size was determined using cranial ultrasounds. The relationships between CSF APP, L1CAM, and NCAM-1, occipitofrontal circumference (OFC, volume of CSF removed, and ventricular size were examined using correlation and regression analyses.CSF levels of APP, L1CAM, and NCAM-1 but not TP paralleled treatment-related changes in ventricular size. CSF APP demonstrated the strongest association with ventricular size, estimated by frontal-occipital horn ratio (FOR (Pearson R = 0.76, p = 0.004, followed by NCAM-1 (R = 0.66, p = 0.02 and L1CAM (R = 0.57,p = 0.055. TP was not correlated with FOR (R = 0.02, p = 0.95.Herein, we report the novel observation that CSF APP shows a robust association with ventricular size in preterm infants treated for PHH. The results from this study suggest that CSF APP and related proteins at once hold promise as biomarkers of PHH and provide insight into the neurological consequences of PHH in the preterm infant.
The associated factors to endometrial cavity fluid and the relevant impact on the IVF-ET outcome
Directory of Open Access Journals (Sweden)
Li Ya-Qiong
2010-05-01
Full Text Available Abstract Background Endometrial cavity fluid (ECF is a fluid accumulation within the endometrial cavity. The significance of ECF remains unclear during the program of in vitro fertilization-embryo transfer (IVF-ET. The aim of the present study was to investigate the associated factors to ECF, visualized through ultrasound at the day of oocyte retrieval, and the relevant impact on the outcome of IVF-ET. Methods From the clinical data of 1557 infertility patients for IVF-ET program, 46 ECF patients were retrospectively selected as the ECF group; and another 134 patients with a bilateral salpingectomy and without ECF, selected as the control group. The demographics and the outcome of IVF-ET were compared between the two groups. Results The incidence of ECF was 2.95% (46/1557. Over half (28/46, 60.87% of ECF patients had tubal infertility. Only 12 Of 46 ECF patients (26.09% had visible hydrosalpinx on ultrasonography before ovarian stimulation. The cycle cancellation rate (4/46, 8.69% of ECF group was not significantly higher than that of the control group (6/134, 4.48%; P > 0.05. Reasons for cycle cancellation in both groups were all the high risk of ovarian hyperstimulation syndrome (OHSS. No significant difference was found in clinical pregnancy rate between the patients with their ECF 0.05. No clinical pregnancy was found among those patients with their ECF equal or higher 3.5 mm in APD. Conclusions It was tubal infertility, not hydrosalpinx, which was related to the development of ECF. Excessive ECF (equal or higher 3.5 mm in APD at the day of oocyte retrieval would have a negative impact on the outcome of IVF-ET.
Energy Technology Data Exchange (ETDEWEB)
Kim, Kyung Won; Shinagare, Atul B.; Krajewski, Katherine M.; Tirumani, Sree Harsha; Jagannathan, Jyothi P.; Ramaiya, Nikihil H. [Dept. of Imaging, Dana-Farber Cancer Institute, Brigham and Women' s Hospital, Harvard Medical School, Boston (United States); Pyo, Jun Hee [The Institute for Clinical Research and Health Policy Studies, Tufts Medical Center, Boston (United States)
2015-04-15
We aimed to describe radiologic signs and time-course of imatinib-associated fluid retention (FR) in patients with gastrointestinal stromal tumor (GIST), and its implications for management. In this Institutional Review Board-approved, retrospective study of 403 patients with GIST treated with imatinib, 15 patients with imaging findings of FR were identified by screening radiology reports, followed by manual confirmation. Subcutaneous edema, ascites, pleural effusion, and pericardial effusion were graded on a four-point scale on CT scans; total score was the sum of these four scores. The most common radiologic sign of FR was subcutaneous edema (15/15, 100%), followed by ascites (12/15, 80%), pleural effusion (11/15, 73%), and pericardial effusion (6/15, 40%) at the time of maximum FR. Two distinct types of FR were observed: 1) acute/progressive FR, characterized by acute aggravation of FR and rapid improvement after management, 2) intermittent/steady FR, characterized by occasional or persistent mild FR. Acute/progressive FR always occurred early after drug initiation/dose escalation (median 1.9 month, range 0.3-4.0 months), while intermittent/steady FR occurred at any time. Compared to intermittent/steady FR, acute/progressive FR was severe (median score, 5 vs. 2.5, p = 0.002), and often required drug-cessation/dose-reduction. Two distinct types (acute/progressive and intermittent/steady FR) of imatinib-associated FR are observed and each type requires different management.
Investigation of the Phase Equilibria and Interfacial Properties for Non-polar Fluids
Institute of Scientific and Technical Information of China (English)
付东; 赵毅
2005-01-01
A self-consistent density-functional theory (DFT) was applied to investigate the phase behavior and interfacial properties of non-polar fluids. For the bulk phases, the theory was reduced to the statistical associating fluid theory(SAFF) that provides accurate descriptions of vapor-liquid phase diagrams below the critical region. The phase diagrams in the critical region were corrected by the renormalization group theory (RGT). The density profile in the surface was obtained by minimizing the grand potential. With the same set of molecular parameters, both the phase equilibria and the interfacial properties of non-polar fluids were investigated satisfactorily.
Associative memory in a volume holographic medium: a new approach based on operator theory
International Nuclear Information System (INIS)
In this article, we present a new method for holographic implementation of associative memories. In the current approach, the memory capacity is implemented in the form of spatial perturbation of refractive index within the volume of a three dimensional holographic material. We use operator theory to solve the inverse problem and compute a closed-form solution for the spatial distribution of the perturbation considering any arbitrary set of input–output prototype vectors. Simplicity of the hardware is the major advantage of the current method. (papers)
Associative memory in a volume holographic medium: a new approach based on operator theory
Pashaie, Ramin
2014-07-01
In this article, we present a new method for holographic implementation of associative memories. In the current approach, the memory capacity is implemented in the form of spatial perturbation of refractive index within the volume of a three dimensional holographic material. We use operator theory to solve the inverse problem and compute a closed-form solution for the spatial distribution of the perturbation considering any arbitrary set of input-output prototype vectors. Simplicity of the hardware is the major advantage of the current method.
Lachnit, Harald; Thorwart, Anna; Schultheis, Holger; Lotz, Anja; Koenig, Stephan; Uengoer, Metin
2013-01-01
In four human learning experiments (Pavlovian skin conductance, causal learning, speeded classification task), we evaluated several associative learning theories that assume either an elemental (modified unique cue model and Harris’ model) or a configural (Pearce’s configural theory and an extension of it) form of stimulus processing. The experiments used two modified patterning problems (A/B/C+, AB/BC/AC+ vs. ABC-; A+, BC+ vs. ABC-). Pearce’s configural theory successfully predicted all of o...
Directory of Open Access Journals (Sweden)
Joseph N Jarvis
2015-04-01
Full Text Available Understanding the host immune response during cryptococcal meningitis (CM is of critical importance for the development of immunomodulatory therapies. We profiled the cerebrospinal fluid (CSF immune-response in ninety patients with HIV-associated CM, and examined associations between immune phenotype and clinical outcome. CSF cytokine, chemokine, and macrophage activation marker concentrations were assayed at disease presentation, and associations between these parameters and microbiological and clinical outcomes were examined using principal component analysis (PCA. PCA demonstrated a co-correlated CSF cytokine and chemokine response consisting primarily of Th1, Th2, and Th17-type cytokines. The presence of this CSF cytokine response was associated with evidence of increased macrophage activation, more rapid clearance of Cryptococci from CSF, and survival at 2 weeks. The key components of this protective immune-response were interleukin (IL-6 and interferon-γ, IL-4, IL-10 and IL-17 levels also made a modest positive contribution to the PC1 score. A second component of co-correlated chemokines was identified by PCA, consisting primarily of monocyte chemotactic protein-1 (MCP-1 and macrophage inflammatory protein-1α (MIP-1α. High CSF chemokine concentrations were associated with low peripheral CD4 cell counts and CSF lymphocyte counts and were predictive of immune reconstitution inflammatory syndrome (IRIS. In conclusion CSF cytokine and chemokine profiles predict risk of early mortality and IRIS in HIV-associated CM. We speculate that the presence of even minimal Cryptococcus-specific Th1-type CD4+ T-cell responses lead to increased recruitment of circulating lymphocytes and monocytes into the central nervous system (CNS, more effective activation of CNS macrophages and microglial cells, and faster organism clearance; while high CNS chemokine levels may predispose to over recruitment or inappropriate recruitment of immune cells to the CNS and
Dharma-wardana, M W C
2016-01-01
Using data from recent laser-shock experiments and related density-functional molecular-dynamics simulations on carbon, we demonstrate that the ionic structures predicted within the neutral-pseudo-atom approach for a complex liquid in the warm-dense matter regime are in good agreement with available data, even where transient covalent bonding dominates ionic correlations. Evidence for an unusual phase transition of a liquid $\\to$ vapor with an abrupt decrease in ionization occurring simultaneously is presented. Here a covalently-bonded metallic-liquid, i.e., carbon of density 1.0 g/cm$^3$, transits to a disordered mono-atomic fluid at 7 eV. Other transitions where the mean ionization $Z$ drops abruptly are also uncovered
Institute of Scientific and Technical Information of China (English)
无
2006-01-01
In order to resolve the multisensor multiplied maneuvering target tracking problem, this paper presents a distributed interacted multiple model multisensor joint probabilistic data association algorithm (DIMM-MSJPDA). First of all, the interacted multiple model joint probabilistic data association algorithm is applied to each sensor, and then the state estimation, estimation covariance, model probability, combined innovation, innovation covariance are delivered to the fusion center. Then, the tracks from each sensor are correlated and the D-S evidence theory is used to gain the model probability of an identical target. Finally, the ultimate state estimation of each target is calculated according to the new model probability, and the state estimation is transmitted to each sensor. Simulations are designed to test the tracking performance of DIMM-MSJPDA algorithm. The results show that the use of DIMM-MSJPDA algorithm enables the distributed multisensor system to track multiplied maneuvering targets and its tracking performance is much better than that of IMMJPDA algorithm.
Institute of Scientific and Technical Information of China (English)
CHEN Lu-wang; QIN Yuan; GUI He-rong; ZHANG Shi-lei
2012-01-01
To study the behavior of overlying strata and the likelihood of water inrush and quicksand with different mining sequences under an unconsolidated alluvium aquifer,a numerical model based on the fluid-solid coupling theory was constructed by FLAC3D.Simulation results revealed that the mining sequences had a significant influence on the seepage,displacement and failure characteristics of the overlying strata.In this kind of geological and hydrogeological conditions,the workface close to the outcrop of coal seam easily suffers from water inrush and quicksand during mining.In the simulation resuits,the plastic zone,vertical displacement and pore water pressure in the overlying strata of the workface decrease more or less using the upward mining sequence than using the downward mining sequence.Therefore,the application of the upward mining sequence in the process of mining is preferential to prevent water inrush and quicksand.
DEFF Research Database (Denmark)
Larsson, S; Englund, M; Struglics, A;
2015-01-01
OBJECTIVE: To explore potential associations between proinflammatory cytokines in synovial fluid and progression of osteoarthritis (OA) in meniscectomized subjects. DESIGN: We studied 132 subjects on average 18 years after meniscectomy, with a second examination 4-10 years later. We measured conc...
DEFF Research Database (Denmark)
Larsson, S; Englund, M; Struglics, A;
2012-01-01
OBJECTIVE: To investigate whether change in concentrations over time of aggrecanase generated ARGS-aggrecan in synovial fluid (SF ARGS) associates with progression of radiographic knee osteoarthritis (OA) and patient-reported outcome in subjects with previous meniscectomy. METHODS: We studied 141...
Directory of Open Access Journals (Sweden)
Caimmi, R.
2008-06-01
Full Text Available A theory of collisionless fluids is developed in a unified picture, where nonrotating $(widetilde{Omega_1}=widetilde{Omega_2}= widetilde{Omega_3}=0$ figures with some given random velocity component distributions, and rotating $(widetilde{Omega_1} ewidetilde{Omega_2} e widetilde{Omega_3} $ figures with a different random velocity component distributions, make adjoint configurations to the same system. R fluids are defined as ideal, self-gravitating fluids satisfying the virial theorem assumptions, in presence of systematic rotation around each of the principal axes of inertia. To this aim, mean and rms angular velocities and mean and rms tangential velocity components are expressed, by weighting on the moment of inertia and the mass, respectively. The figure rotation is defined as the mean angular velocity, weighted on the moment of inertia, with respectto a selected axis. The generalized tensor virial equations (Caimmi and Marmo 2005 are formulated for R fluidsand further attention is devoted to axisymmetric configurations where, for selected coordinateaxes, a variation in figure rotation has to be counterbalanced by a variation in anisotropy excess and viceversa. A microscopical analysis of systematic and random motions is performed under a fewgeneral hypotheses, by reversing the sign of tangential or axial velocity components of anassigned fraction of particles, leaving the distribution function and other parametersunchanged (Meza 2002. The application of the reversion process to tangential velocitycomponents is found to imply the conversion of random motion rotation kinetic energy intosystematic motion rotation kinetic energy. The application ofthe reversion process to axial velocity components is found to imply the conversionof random motion translation kinetic energy into systematic motion translation kinetic energy, and theloss related to a change of reference frame is expressed in terms of systematic motion (imaginary rotation kinetic
Tretyakov, Nikita; Vollmer, Doris; Butt, Hans-Jürgen; Dünweg, Burkhard; Daoulas, Kostas Ch
2016-01-01
Classical density functional theory is applied to investigate the validity of a phenomenological force-balance description of the stability of the Cassie state of liquids on substrates with nanoscale corrugation. A bulk free-energy functional of third order in local density is combined with a square-gradient term, describing the liquid-vapor interface. The bulk free energy is parameterized to reproduce the liquid density and the compressibility of water. The square-gradient term is adjusted to model the width of the water-vapor interface. The substrate is modeled by an external potential, based upon Lennard-Jones interactions. The three-dimensional calculation focuses on substrates patterned with nanostripes and square-shaped nanopillars. Using both the force-balance relation and density-functional theory, we locate the Cassie-to-Wenzel transition as a function of the corrugation parameters. We demonstrate that the force-balance relation gives a qualitatively reasonable description of the transition even on t...
Directory of Open Access Journals (Sweden)
P. Mazzanti
2009-11-01
Full Text Available Coastal and subaqueous landslides can be very dangerous phenomena since they are characterised by the additional risk of induced tsunamis, unlike their completely-subaerial counterparts. Numerical modelling of landslides propagation is a key step in forecasting the consequences of landslides. In this paper, a novel approach named Equivalent Fluid/Equivalent Medium (EFEM has been developed. It adapts common numerical models and software that were originally designed for subaerial landslides in order to simulate the propagation of combined subaerial-subaqueous and completely-subaqueous landslides. Drag and buoyancy forces, the loss of energy at the landslide-water impact and peculiar mechanisms like hydroplaning can be suitably simulated by this approach; furthermore, the change in properties of the landslide's mass, which is encountered at the transition from the subaerial to the submerged environment, can be taken into account. The approach has been tested by modelling two documented coastal landslides (a debris flow and a rock slide at Lake Albano using the DAN-W code. The results, which were achieved from the back-analyses, demonstrate the efficacy of the approach to simulate the propagation of different types of coastal landslides.
Mazzanti, P.; Bozzano, F.
2009-11-01
Coastal and subaqueous landslides can be very dangerous phenomena since they are characterised by the additional risk of induced tsunamis, unlike their completely-subaerial counterparts. Numerical modelling of landslides propagation is a key step in forecasting the consequences of landslides. In this paper, a novel approach named Equivalent Fluid/Equivalent Medium (EFEM) has been developed. It adapts common numerical models and software that were originally designed for subaerial landslides in order to simulate the propagation of combined subaerial-subaqueous and completely-subaqueous landslides. Drag and buoyancy forces, the loss of energy at the landslide-water impact and peculiar mechanisms like hydroplaning can be suitably simulated by this approach; furthermore, the change in properties of the landslide's mass, which is encountered at the transition from the subaerial to the submerged environment, can be taken into account. The approach has been tested by modelling two documented coastal landslides (a debris flow and a rock slide at Lake Albano) using the DAN-W code. The results, which were achieved from the back-analyses, demonstrate the efficacy of the approach to simulate the propagation of different types of coastal landslides.
Bianchi type-V cosmological models with perfect fluid and heat flow in Saez–Ballester theory
Indian Academy of Sciences (India)
Shri Ram; M Zeyauddin; C P Singh
2009-02-01
In this paper we discuss the variation law for Hubble's parameter with average scale factor in a spatially homogeneous and anisotropic Bianchi type-V space-time model, which yields constant value of the deceleration parameter. We derive two laws of variation of the average scale factor with cosmic time, one is of power-law type and the other is of exponential form. Exact solutions of Einstein field equations with perfect fluid and heat conduction are obtained for Bianchi type-V space-time in these two types of cosmologies. In the cosmology with the power-law, the solutions correspond to a cosmological model which starts expanding from the singular state with positive deceleration parameter. In the case of exponential cosmology, we present an accelerating non-singular model of the Universe. We find that the constant value of deceleration parameter is reasonable for the present day Universe and gives an appropriate description of evolution of Universe. We have also discussed different types of physical and kinematical behaviour of the models in these two types of cosmologies.
Directory of Open Access Journals (Sweden)
Galasko Douglas
2010-01-01
Full Text Available Abstract Background Alzheimer's disease (AD is associated with deposition of amyloid β (Aβ in the brain, which is reflected by low concentration of the Aβ1-42 peptide in the cerebrospinal fluid (CSF. There are at least 15 additional Aβ peptides in human CSF and their relative abundance pattern is thought to reflect the production and degradation of Aβ. Here, we test the hypothesis that AD is characterized by a specific CSF Aβ isoform pattern that is distinct when comparing sporadic AD (SAD and familial AD (FAD due to different mechanisms underlying brain amyloid pathology in the two disease groups. Results We measured Aβ isoform concentrations in CSF from 18 patients with SAD, 7 carriers of the FAD-associated presenilin 1 (PSEN1 A431E mutation, 17 healthy controls and 6 patients with depression using immunoprecipitation-mass spectrometry. Low CSF levels of Aβ1-42 and high levels of Aβ1-16 distinguished SAD patients and FAD mutation carriers from healthy controls and depressed patients. SAD and FAD were characterized by similar changes in Aβ1-42 and Aβ1-16, but FAD mutation carriers exhibited very low levels of Aβ1-37, Aβ1-38 and Aβ1-39. Conclusion SAD patients and PSEN1 A431E mutation carriers are characterized by aberrant CSF Aβ isoform patterns that hold clinically relevant diagnostic information. PSEN1 A431E mutation carriers exhibit low levels of Aβ1-37, Aβ1-38 and Aβ1-39; fragments that are normally produced by γ-secretase, suggesting that the PSEN1 A431E mutation modulates γ-secretase cleavage site preference in a disease-promoting manner.
Directory of Open Access Journals (Sweden)
Masaru Takeuchi
Full Text Available Macrophages are involved in low-grade inflammation in diabetes, and play pathogenic roles in proliferative diabetic retinopathy (PDR by producing proinflammatory cytokines. T cells as well as other cells are also activated by proinflammatory cytokines, and infiltration into the vitreous of patients with PDR has been shown. In this study, we measured helper T (Th cell-related cytokines in the vitreous of PDR patients to define the characteristics of Th-mediated immune responses associated with PDR. The study group consisted of 25 type 2 diabetic patients (25 eyes with PDR. The control group consisted of 27 patients with epiretinal membrane (ERM, 26 patients with idiopathic macular hole (MH, and 26 patients with uveitis associated with sarcoidosis. Vitreous fluid was obtained at the beginning of vitrectomy, and centrifuging for cellular removals was not performed. Serum was also collected from PDR patients. IL-1β, IL-4, IL-6, IL-10, IL-17A, IL-17F, IL-21, IL-22, IL-23, IL-25, IL-31, IL-33, IFN-γ, soluble sCD40L, and TNFα in the vitreous and serum samples were measured. Both percent detectable and levels of IL-4, IL-6, IL-17A, IL-21, IL-22, and TNFα in the vitreous were significantly higher than those in the serum in PDR patients. Vitreous levels of these cytokines and IL-31 were significantly higher in PDR than in ERM or MH patients. Vitreous levels of IL-4, IL-17A, IL-22, IL-31, and TNFα in PDR patients were also significantly higher than those of sarcoidosis patients. In PDR patients, vitreous IL-17A level correlated significantly with vitreous levels of IL-22 and IL-31, and especially with IL-4 and TNFα. Although it is unclear whether these cytokines play facilitative roles or inhibitory roles for the progression of PDR, the present study indicated that Th2- and Th17-related immune responses are involved in the pathogenesis of PDR.
Puchhammer-Stöckl, E; Popow-Kraupp, T; Heinz, F X; Mandl, C W; Kunz, C.
1991-01-01
The polymerase chain reaction (PCR) was used to detect varicella-zoster virus (VZV) DNA in the cerebrospinal fluid of patients with VZV infection associated with neurological symptoms. Positive results were obtained in three of five children with post-chicken pox cerebellitis and in seven of seven herpes zoster patients with neurological symptoms. The PCR thus provides a useful tool for the early diagnosis of VZV-associated neurological disease.
Energy Technology Data Exchange (ETDEWEB)
Perfetti, E
2006-11-15
Modelling fluid-rock interactions as well as mixing and unmixing phenomena in geological processes requires robust equations of state (EOS) which must be applicable to systems containing water, gases over a broad range of temperatures and pressures. Cubic equations of state based on the Van der Waals theory (e. g. Soave-Redlich-Kwong or Peng-Robinson) allow simple modelling from the critical parameters of the studied fluid components. However, the accuracy of such equations becomes poor when water is a major component of the fluid since neither association trough hydrogen bonding nor dipolar interactions are accounted for. The Helmholtz energy of a fluid may be written as the sum of different energetic contributions by factorization of partition function. The model developed in this thesis for the pure H{sub 2}O and H{sub 2}S considers three contributions. The first contribution represents the reference Van der Waals fluid which is modelled by the SRK cubic EOS. The second contribution accounts for association through hydrogen bonding and is modelled by a term derived from Cubic Plus Association (CPA) theory. The third contribution corresponds to the dipolar interactions and is modelled by the Mean Spherical Approximation (MSA) theory. The resulting CPAMSA equation has six adjustable parameters, which three represent physical terms whose values are close to their experimental counterpart. This equation results in a better reproduction of the thermodynamic properties of pure water than obtained using the classical CPA equation along the vapour-liquid equilibrium. In addition, extrapolation to higher temperatures and pressure is satisfactory. Similarly, taking into account dipolar interactions together with the SRK cubic equation of state for calculating molar volume of H{sub 2}S as a function of pressure and temperature results in a significant improvement compared to the SRK equation alone. Simple mixing rules between dipolar molecules are proposed to model the H
Swami, Viren; Weis, Laura; Lay, Alixe; Barron, David; Furnham, Adrian
2016-02-28
Conspiracy theories can be treated as both rational narratives of the world as well as outcomes of underlying maladaptive traits. Here, we examined associations between belief in conspiracy theories and individual differences in personality disorders. An Internet-based sample (N=259) completed measures of belief in conspiracy theories and the 25 facets of the Personality Inventory for DSM-5 (PID-5). Preliminary analyses showed no significant differences in belief in conspiracy theories across participant sex, ethnicity, and education. Regression analyses showed that the PID-5 facets of Unusual Beliefs and Experiences and, to a lesser extent, Suspiciousness, significantly predicted belief in conspiracy theories. These findings highlight a role for maladaptive personality traits in understanding belief in conspiracy theories, but require further investigation.
Swami, Viren; Weis, Laura; Lay, Alixe; Barron, David; Furnham, Adrian
2016-02-28
Conspiracy theories can be treated as both rational narratives of the world as well as outcomes of underlying maladaptive traits. Here, we examined associations between belief in conspiracy theories and individual differences in personality disorders. An Internet-based sample (N=259) completed measures of belief in conspiracy theories and the 25 facets of the Personality Inventory for DSM-5 (PID-5). Preliminary analyses showed no significant differences in belief in conspiracy theories across participant sex, ethnicity, and education. Regression analyses showed that the PID-5 facets of Unusual Beliefs and Experiences and, to a lesser extent, Suspiciousness, significantly predicted belief in conspiracy theories. These findings highlight a role for maladaptive personality traits in understanding belief in conspiracy theories, but require further investigation. PMID:26776299
Energy Technology Data Exchange (ETDEWEB)
House, William H.; Pritchett, John A. [Amoco Production Co. (United States)
1995-12-31
The emplacement of allochthonous salt bodies in the Northern Gulf of Mexico, and their subsequent deformation to form secondary salt features involves the upward movement of salt along discrete feeder conduits. The detachment of allochthonous salt from a deeper source results in the collapse of these conduits. Structural disruption associated with this collapse creates a permeability pathway to allow enhanced fluid migration from depth into shallower section. Some of the high pressure fluids migration upward along these permeability conduits will impinge on a permeability barrier created by the horizontal to sub-horizontal base of allochthonous salt sheets. Additional high pressure fluids associated with shale compaction and dewatering will also move upward to the base of salt permeability barrier. The constant influx of high pressure fluids into the zone immediately below salt prevents the shale in this zone from undergoing normal compaction, resulting in the formation of a lithologically distinct gumbo zone. This gumbo zone has been encountered in many of the subsalt wells drilled in the Gulf of Mexico. Abnormally high pore pressures are often associated with this gumbo zone beneath the salt sheets covering the southern shelf area, offshore Louisiana. Formation pressure gradients within this zone can be as much as 0.04 psi/ft (0.8 ppg) above the regional pressure gradient. (author). 4 refs., 1 fig
Bird, R. Byron
1980-01-01
Problems in polymer fluid dynamics are described, including development of constitutive equations, rheometry, kinetic theory, flow visualization, heat transfer studies, flows with phase change, two-phase flow, polymer unit operations, and drag reduction. (JN)
Härtel, Andreas; Samin, Sela; van Roij, René
2016-06-22
The ongoing scientific interest in the properties and structure of electric double layers (EDLs) stems from their pivotal role in (super)capacitive energy storage, energy harvesting, and water treatment technologies. Classical density functional theory (DFT) is a promising framework for the study of the in- and out-of-plane structural properties of double layers. Supported by molecular dynamics simulations, we demonstrate the adequate performance of DFT for analyzing charge layering in the EDL perpendicular to the electrodes. We discuss charge storage and capacitance of the EDL and the impact of screening due to dielectric solvents. We further calculate, for the first time, the in-plane structure of the EDL within the framework of DFT. While our out-of-plane results already hint at structural in-plane transitions inside the EDL, which have been observed recently in simulations and experiments, our DFT approach performs poorly in predicting in-plane structure in comparison to simulations. However, our findings isolate fundamental issues in the theoretical description of the EDL within the primitive model and point towards limitations in the performance of DFT in describing the out-of-plane structure of the EDL at high concentrations and potentials. PMID:27116552
Härtel, Andreas; Samin, Sela; van Roij, René
2016-06-01
The ongoing scientific interest in the properties and structure of electric double layers (EDLs) stems from their pivotal role in (super)capacitive energy storage, energy harvesting, and water treatment technologies. Classical density functional theory (DFT) is a promising framework for the study of the in- and out-of-plane structural properties of double layers. Supported by molecular dynamics simulations, we demonstrate the adequate performance of DFT for analyzing charge layering in the EDL perpendicular to the electrodes. We discuss charge storage and capacitance of the EDL and the impact of screening due to dielectric solvents. We further calculate, for the first time, the in-plane structure of the EDL within the framework of DFT. While our out-of-plane results already hint at structural in-plane transitions inside the EDL, which have been observed recently in simulations and experiments, our DFT approach performs poorly in predicting in-plane structure in comparison to simulations. However, our findings isolate fundamental issues in the theoretical description of the EDL within the primitive model and point towards limitations in the performance of DFT in describing the out-of-plane structure of the EDL at high concentrations and potentials.
Eringen, A Cemal
1999-01-01
Microcontinuum field theories constitute an extension of classical field theories -- of elastic bodies, deformations, electromagnetism, and the like -- to microscopic spaces and short time scales. Material bodies are here viewed as collections of large numbers of deformable particles, much as each volume element of a fluid in statistical mechanics is viewed as consisting of a large number of small particles for which statistical laws are valid. Classical continuum theories are valid when the characteristic length associated with external forces or stimuli is much larger than any internal scale of the body under consideration. When the characteristic lengths are comparable, however, the response of the individual constituents becomes important, for example, in considering the fluid or elastic properties of blood, porous media, polymers, liquid crystals, slurries, and composite materials. This volume is concerned with the kinematics of microcontinua. It begins with a discussion of strain, stress tensors, balanc...
Directory of Open Access Journals (Sweden)
Schaller Carlo
2008-12-01
Full Text Available Abstract Background In human neonatal high pressure hydrocephalus (HPHC, diffuse white matter injury and gliosis predispose to poor neuro-developmental outcome. The underlying mechanism for diffuse white matter damage in neonatal HPHC is still unclear. Analogous to inflammatory white matter damage after neonatal hypoxemia/ischemia, we hypothesized that pro-inflammatory cytokines could be involved in neonatal HPHC. If so, early anti-inflammatory therapy could ameliorate white matter damage in HPHC, before irreversible apoptosis has occurred. In HPHC and control neonates, we therefore aimed to compare cerebrospinal fluid (CSF concentrations of IL18, IFNγ and sFasL (interleukin 18, interferon gamma and apoptosis marker soluble-Fas ligand, respectively. Methods In neonatal HPHC (n = 30 and controls (n = 15, we compared CSF concentrations of IL18, IFNγ and sFasL using sandwich ELISA. HPHC was grouped according to etiology: spina bifida aperta (n = 20, aqueduct stenosis (n = 4, and fetal intra-cerebral haemorrhage (n = 6. Neonatal control CSF was derived from otherwise healthy neonates (n = 15, who underwent lumbar puncture for exclusion of meningitis. Results In all three HPHC groups, CSF IL18 concentrations were significantly higher than control values, and the fetal intracranial haemorrhage group was significantly higher than SBA group. Similarly, in all HPHC groups CSF-IFNγ concentrations significantly exceeded the control group. In both HPHC and control neonates, CSF FasL concentrations remained within the range of reference values. Conclusion Independent of the pathogenesis, neonatal HPHC is associated with the activation of the pro-inflammatory cytokines (IL-18 and IFNγ in the CSF, whereas CSF apoptosis biomarkers (sFasL were unchanged. This suggests that anti-inflammatory treatment (in addition to shunting could be helpful to preserve cerebral white matter.
Ruban, Anatoly I
This is the first book in a four-part series designed to give a comprehensive and coherent description of Fluid Dynamics, starting with chapters on classical theory suitable for an introductory undergraduate lecture course, and then progressing through more advanced material up to the level of modern research in the field. The present Part 1 consists of four chapters. Chapter 1 begins with a discussion of Continuum Hypothesis, which is followed by an introduction to macroscopic functions, the velocity vector, pressure, density, and enthalpy. We then analyse the forces acting inside a fluid, and deduce the Navier-Stokes equations for incompressible and compressible fluids in Cartesian and curvilinear coordinates. In Chapter 2 we study the properties of a number of flows that are presented by the so-called exact solutions of the Navier-Stokes equations, including the Couette flow between two parallel plates, Hagen-Poiseuille flow through a pipe, and Karman flow above an infinite rotating disk. Chapter 3 is d...
Membrane fluids and Dirac membrane fluids
Ivanov, M G
2004-01-01
The relation between two different methods of membrane fluid description is clarified by construction of combined method. Dirac membrane field appears naturally in new approach. It provides a possibility to consider new aspects of electrodynamics-type theories with electric and magnetic sources. The membrane fluid models automatically prohibit simulatenos existence of electric and magnetic currents. Possible applications to the dark energy problem are mentioned.
Institute of Scientific and Technical Information of China (English)
Haibin Huang; Xunliang Mai; Xiaohong Ye
2006-01-01
BACKGROUND: Guillain-Barre syndrome (GBS) is an autoimmune disease which is characterized by demyelination of peripheral nerve and nerve root, and inflammatory reaction of lymphocyte and macrophage. Neuroelectrophysiological examination and cerebrospinal fluid (CSF) analysis are of significance for its diagnosis.OBJECTIVE: To study the association of neuroelectrophysiology and cerebrospinal fluid immunoglobulin (CSF-Ig) with pathogenetic conditions of patients with GBS.DESIGN: Case control study.SETTING: Department of Neurology, Shenzhen Municipal Shekou Group Hospital; Department of Neuroelectrophysiology, People's Hospital of Guangdong Province.PARTICIPANTS: A total of 32 GBS patients including 18 males and 14 females who aged from 17 to 72 years were selected as experimental group from the Department of Neurology, People's Hospital of Guangdong Province from January 2004 to December 2005. All cases conformed with GBS diagnostic criteria established by Asbury in 1990 and they were divided into three types according to neurological criteria established by Chinese Neurology and Psychology Journal in 1993: mild, moderate and severe types. Another 30 patients with vascular headache were selected as control group from the same hospital including 14 males and 16 females who aged from 17 to 79 years.METHODS: ① Neuroelectrophysiological examination: Multiple-functional electromyography device provided by Nicolet Company, USA was used to measure nerve conduction velocity (NCV), including motor nerve conduction velocity (MCV) and sensory nerve conduction velocity (SCV); meanwhile, electromyologram (EMG), somatosensory evoked potential (SEP) and electroencephalogram (EEG) were also measured. ② Detection of CSF-Ig: Concentrations of IgG, IgA and IgM were measured with immunofixation electrophoresis. ③ Follow-up: Among 32 GBS patients, 14 cases received follow-up after treatment and the longest follow-up time was 1 year after onset. Among them, 8 cases were reexaminined
Chan, Ho Yin; Lubchenko, Vassiliy
2015-09-28
We set up the problem of finding the transition state for phase nucleation in multi-component fluid mixtures, within the Landau-Ginzburg density functional. We establish an expression for the coordinate-dependent local pressure that applies to mixtures, arbitrary geometries, and certain non-equilibrium configurations. The expression allows one to explicitly evaluate the pressure in spherical geometry, à la van der Waals. Pascal's law is recovered within the Landau-Ginzburg density functional theory, formally analogously to how conservation of energy is recovered in the Lagrangian formulation of mechanics. We establish proper boundary conditions for certain singular functional forms of the bulk free energy density that allow one to obtain droplet solutions with thick walls in essentially closed form. The hydrodynamic modes responsible for mixing near the interface are explicitly identified in the treatment; the composition at the interface is found to depend only weakly on the droplet size. Next we develop a Landau-Ginzburg treatment of the effects of amphiphiles on the surface tension; the amphiphilic action is seen as a violation of Pascal's law. We explicitly obtain the binding potential for the detergent at the interface and the dependence of the down-renormalization of the surface tension on the activity of the detergent. Finally, we argue that the renormalization of the activation barrier for escape from long-lived structures in glassy liquids can be viewed as an action of uniformly seeded, randomly oriented amphiphilic molecules on the interface separating two dissimilar aperiodic structures. This renormalization is also considered as a "wetting" of the interface. The resulting conclusions are consistent with the random first order transition theory. PMID:26429019
Chan, Ho Yin; Lubchenko, Vassiliy
2015-09-28
We set up the problem of finding the transition state for phase nucleation in multi-component fluid mixtures, within the Landau-Ginzburg density functional. We establish an expression for the coordinate-dependent local pressure that applies to mixtures, arbitrary geometries, and certain non-equilibrium configurations. The expression allows one to explicitly evaluate the pressure in spherical geometry, à la van der Waals. Pascal's law is recovered within the Landau-Ginzburg density functional theory, formally analogously to how conservation of energy is recovered in the Lagrangian formulation of mechanics. We establish proper boundary conditions for certain singular functional forms of the bulk free energy density that allow one to obtain droplet solutions with thick walls in essentially closed form. The hydrodynamic modes responsible for mixing near the interface are explicitly identified in the treatment; the composition at the interface is found to depend only weakly on the droplet size. Next we develop a Landau-Ginzburg treatment of the effects of amphiphiles on the surface tension; the amphiphilic action is seen as a violation of Pascal's law. We explicitly obtain the binding potential for the detergent at the interface and the dependence of the down-renormalization of the surface tension on the activity of the detergent. Finally, we argue that the renormalization of the activation barrier for escape from long-lived structures in glassy liquids can be viewed as an action of uniformly seeded, randomly oriented amphiphilic molecules on the interface separating two dissimilar aperiodic structures. This renormalization is also considered as a "wetting" of the interface. The resulting conclusions are consistent with the random first order transition theory.
Chan, Ho Yin; Lubchenko, Vassiliy
2015-09-01
We set up the problem of finding the transition state for phase nucleation in multi-component fluid mixtures, within the Landau-Ginzburg density functional. We establish an expression for the coordinate-dependent local pressure that applies to mixtures, arbitrary geometries, and certain non-equilibrium configurations. The expression allows one to explicitly evaluate the pressure in spherical geometry, à la van der Waals. Pascal's law is recovered within the Landau-Ginzburg density functional theory, formally analogously to how conservation of energy is recovered in the Lagrangian formulation of mechanics. We establish proper boundary conditions for certain singular functional forms of the bulk free energy density that allow one to obtain droplet solutions with thick walls in essentially closed form. The hydrodynamic modes responsible for mixing near the interface are explicitly identified in the treatment; the composition at the interface is found to depend only weakly on the droplet size. Next we develop a Landau-Ginzburg treatment of the effects of amphiphiles on the surface tension; the amphiphilic action is seen as a violation of Pascal's law. We explicitly obtain the binding potential for the detergent at the interface and the dependence of the down-renormalization of the surface tension on the activity of the detergent. Finally, we argue that the renormalization of the activation barrier for escape from long-lived structures in glassy liquids can be viewed as an action of uniformly seeded, randomly oriented amphiphilic molecules on the interface separating two dissimilar aperiodic structures. This renormalization is also considered as a "wetting" of the interface. The resulting conclusions are consistent with the random first order transition theory.
Fiszdon, W
1965-01-01
Fluid Dynamics Transactions, Volume 2 compiles 46 papers on fluid dynamics, a subdiscipline of fluid mechanics that deals with fluid flow. The topics discussed in this book include developments in interference theory for aeronautical applications; diffusion from sources in a turbulent boundary layer; unsteady motion of a finite wing span in a compressible medium; and wall pressure covariance and comparison with experiment. The certain classes of non-stationary axially symmetric flows in magneto-gas-dynamics; description of the phenomenon of secondary flows in curved channels by means of co
Takai, K.; Ishibashi, J.; Lupton, J.; Ueno, Y.; Nunoura, T.; Hirayama, H.; Horikoshi, K.; Suzuki, R.; Hamasaki, H.; Suzuki, Y.
2006-12-01
A newly discovered hydrothermal field called the Mariner field at the northernmost central Valu Fa Ridge (VFR) in the Lau Basin was explored and characterized by geochemical and microbiological surveys. The hydrothermal fluid (max. 365 u^C) emitting from the most vigorous vent site (Snow chimney) was boiling just beneath the seafloor at a water depth of 1908 m and two end-members of hydrothermal fluid were identified. Mineral and fluid chemistry of typical brine-rich (Snow chimney and Monk chimney) and vapor-rich (Crab Restaurant chimney) hydrothermal fluids and the host chimney structures were analyzed. Microbial community structures in three chimney structures were also investigated by culture-dependent and - independent analyses. The 16S rRNA gene clone analysis revealed that both bacterial and archaeal rRNA gene communities at the chimney surface zones were different among three chimneys. The bacterial and archaeal rRNA gene communities of the Snow chimney surface were very similar with those in the dead chimneys, suggesting concurrence of metal sulfide deposition at the inside and weathering at the surface potentially due to its large structure and size. Cultivation analysis demonstrated the significant variation in culturability of various microbial components, particularly of thermophilic H2- and/or S-oxidizing chemolithoautotrophs such as the genera Aquifex and Persephonella, among the chimney sites. The culturability of these chemolithoautotrophs might be associated with the input of gaseous energy and carbon sources like H2S, H2 and CH4 from the hydrothermal fluids, and might be affected by phase-separation- controlled fluid chemistry. In addition, inter-fields comparison of microbial community structures determined by cultivation analysis revealed novel characteristics of the microbial communities in the Mariner field of the Lau Basin among the global deep-sea hydrothermal systems.
DEFF Research Database (Denmark)
Andreou, Dimitrios; Saetre, Peter; Kähler, Anna K;
2011-01-01
The dystrobrevin binding protein-1 (DTNBP1) gene encodes dysbindin-1, a protein involved in neurodevelopmental and neurochemical processes related mainly to the monoamine dopamine. We investigated possible associations between eleven DTNBP1 polymorphisms and cerebrospinal fluid (CSF) concentrations...... of the major dopamine metabolite homovanillic acid (HVA), the major serotonin metabolite 5-hydroxyindoleacetic acid (5-HIAA), and the major noradrenaline metabolite 3-methoxy-4-hydroxyphenylglycol (MHPG) in healthy human subjects (n=132). Two polymorphisms, rs2619538 and rs760666, were nominally...
Sakr, Yasser; Dünisch, Pedro; Santos, Clesar; Matthes, Lena; Zeidan, Mohamed; Reinhart, Konrad; Kalff, Rolf; Ewald, Christian
2016-01-01
Background Aneurysmal subarachnoid hemorrhage (SAH) is a serious condition associated with high mortality rates and long-term disability. We investigated the impact of fluid balance on neurologic outcome after adjustment for possible confounders related to intensive care therapy and extra-cerebral organ failure during the early phase after SAH. Methods In this retrospective study, we analyzed data from all 142 adult patients admitted to our university hospital surgical intensive care unit (IC...
International Nuclear Information System (INIS)
A method for numerically simulating quantum systems is proposed and applied to the two-dimensional electron fluid at T = 0. This method maps quantum systems onto classical ones in the spirit of the classical-map hypernetted-chain theory and performs simulations on the latter. The results of the simulations are free from the assumption of the hypernetted-chain approximation and the neglect of the bridge diagrams. A merit of this method is the applicability to systems with geometrical complexity and finite sizes including the cases at finite temperatures. Monte Carlo and molecular dynamics simulations are performed corresponding to two previous proposals for the 'quantum' temperature and an improvement in the description of the diffraction effect. It is shown that one of these two proposals with the improved diffraction effect gives significantly better agreement with quantum Monte Carlo results reported previously for the range of 5≤rs≤40. These results may serve as the basis for the application of this method to finite non-periodic systems like quantum dots and systems at finite temperatures.
Energy Technology Data Exchange (ETDEWEB)
Lu, Jianbo; Xu, Yanfeng; Wu, Yabo [Liaoning Normal University, Department of Physics, Dalian (China)
2015-10-15
Observations indicate that most of the universal matter is invisible and the gravitational constant G(t) maybe depends on time. A theory of the variational G (VG) is explored in this paper, naturally producing the useful dark components in the universe. We utilize the following observational data: lookback time data, model-independent gamma ray bursts, growth function of matter linear perturbations, type Ia supernovae data with systematic errors, CMB, and BAO, to restrict the unified model (UM) of dark components in VG theory. Using the best-fit values of the parameters with the covariance matrix, constraints on the variation of G are ((G)/(G{sub 0})){sub z=3.5} ≅ 1.0015{sub -0.0075}{sup +0.0071} and ((G)/(G)){sub today} ≅ -0.7252{sub -2.3645}{sup +2.3645} x 10{sup -13} year{sup -1}, with small uncertainties around the constants. The limit on the equation of state of dark matter is w{sub 0dm} = 0.0072{sub -0.0170}{sup +0.0170}, assuming w{sub 0de} = -1 in the unified model, and the dark energy is w{sub 0de} = -0.9986{sub -0.0011}{sup +0.0011}, assuming w{sub 0dm} = 0 a priori. The restrictions on the UM parameters are B{sub s} = 0.7442{sub -0.0132-0.0292}{sup +0.0137+0.0262} and α =0.0002{sub -0.0209-0.0422}{sup +0.0206+0.0441} with 1σ and 2σ confidence level. In addition, the effects of a cosmic string fluid on the unified model in VG theory are investigated. In this case it is found that the Λ CDM (Ω{sub s} = 0, β = 0, and α = 0) is included in this VG-UM model at 1σ confidence level, and larger errors are given: Ω{sub s} = -0.0106{sub -0.0305-0.0509}{sup +0.0312+0.0582} (dimensionless energy density of cosmic string), ((G)/(G{sub 0})){sub z=3.5} ≅ 1.0008{sub -0.0584}{sup +0.0620}, and ((G)/(G)){sub today} ≅ -0.3496{sub -26.3135}{sup +26.3135} x 10{sup -13} year{sup -1}. (orig.)
Classification of mini-dimmings associated with extreme ultraviolet eruptions by using graph theory
Directory of Open Access Journals (Sweden)
S Bazargan
2016-09-01
Full Text Available Coronal dimmings in both micro and macro scales, can be observed by extreme ultraviolet images, recorded from Solar Dynamics Observatory or Atmospheric Imaging Assembly (SDO/AIA. Mini-dimmings are sometimes associated with wave-like brightening, called coronal mass ejections. Here, the sun full disk images with 171 Å wavelenght, cadence of 2.5, and 0.6 arcsec cell size, were taken on 3 March 2012, then the obtained data were analyzed. Using Zernike Moment and Support Vector Machine (SVM, mini dimmings are detected. 538 active region events, 680 coronal hole events and 723 quiet sun events have been recognized using algorithm. The position, time duration and spatial expansion of these events were computed .The eruptive dimmings have a more spatial development than thermal dimmings after eruptions. This is evident in their graph characteristics length. Then, using graph theory, eruptive and thermal mini-dimmings were classified, with 13% error, for 200 dimmings. 68 dimmings were classified as thermal, and 132 as eruptive. To do this, evolution of graph characteristic length were used.
Weber, David E.; Flemer, David A.; Bundrick, Charles M.
1992-09-01
The structure of a macrobenthic invertebrate community associated with the seagrass, Thalassia testudinum, was evaluated under laboratory and field conditions. The research focused on: (1) the effects of pollution stress from a representative drilling fluid used in off-shore oil and gas operations, and (2) a comparison of responses of the seagrass-invertebrate community in the laboratory and field. A series of 15·3 cm diameter cores of the seagrass-invertebrate community was collected from field sites for establishment and sampling of microcosms and in the sampling of field plots over time. Weekly exposures to drilling fluid were conducted in the laboratory microcosms at a mean total suspended matter concentration of 110·7 mg l -1 (± 17·7 SD), and in field plots by usage of acrylic exposure chambers at a mean concentration of 132·8 mg l -1 (±33·3 SD). Standing crop of T. testudinum was not affected by drilling fluid in the laboratory or field when measured after 6 and 12 week exposure periods. The numbers of macrobenthic invertebrates were suppressed by drilling fluid at both exposure periods in the laboratory, but inhibitory effects were absent in the field. Invertebrate densities in the field were similar among control and treated plots, and were much lower than densities occurring in the laboratory control. In most instances, species richness values were similar in the field and laboratory at the end of each 6 and 12 week period.
Stenger, Michael; Hargens, Alan; Dulchavsky, Scott
2014-01-01
Future human space travel will primarily consist of long duration missions onboard the International Space Station or exploration class missions to Mars, its moons, or nearby asteroids. Current evidence suggests that long duration missions might increase risk of permanent ocular structural and functional changes, possibly due to increased intracranial pressure resulting from a spaceflight-induced cephalad (headward) fluid shift.
Giger, S.G.; Heege, J.H. ter; Clennell, M.B.; Wassing, B.B.T.; Ciftci, N.B.; Delle Piane, C.; Harbers, C.; Clark, P.
2009-01-01
A new type of fluid cell has been developed to allow for direct shear deformation of very large and cohesive rock samples under sealed conditions. Rock samples consist of a low-permeability clay or shale layer, which is embedded in porous quartz sandstone to mimic a reservoir-seal pair. The cell is
Selby, D.; Conliffe, J.; Q. G. Crowley; Feely, M
2008-01-01
Late Devonian magmatism in Northern England records key events associated with the Acadian phase of the Caledonian-Appalachian Orogen (C-AO). Zircon U-Pb and molybdenite Re-Os geochronology date emplacement and mineralisation in the Shap (405·2±1·8 Ma), Skiddaw (398·8±0·4 and 392·3±2·8 Ma) and Weardale granites (398·3±1·6 Ma). For the Shap granite, mineralisation and magmatism are contemporaneous, with mineralisation being directly associated with the boiling of CO2-rich magmatic fluids betwe...
Mohammad, Sultan; Schleinitz, Miko; Coutinhoa, João A. P.; Freire, Mara G.
2016-01-01
Due to scarce available experimental data, as well as due to the absence of predictive models, the influence of salts on the solubility of ionic liquids (ILs) in water is still poorly understood. To this end, this work addresses the solubility of the IL 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C4C1im][NTf2]), at 298.15 K and 0.1 MPa, in aqueous salt solutions (from 0.1 to 1.5 mol kg−1). At salt molalities higher than 0.2 mol kg−1, all salts caused salting-out of [C4C1im][NTf2] from aqueous solution with their strength decreasing in the following order: Al2(SO4)3 > ZnSO4 > K3C6H5O7 > KNaC4H4O6 > K3PO4 > Mg(CH3CO2)2 > K2HPO4 > MgSO4 > KH2PO4 > KCH3CO2. Some of these salts lead however to the salting-in of [C4C1im][NTf2] in aqueous medium at salt molalities lower than 0.20 mol kg−1. To attempt the development of a model able to describe the salt effects, comprising both the salting-in and salting-out phenomena observed, the electrolyte Perturbed-Chain Statistical Associating Fluid Theory (ePC-SAFT) was applied using ion-specific parameters. The gathered experimental data was modelled using ePC-SAFT parameters complemented by fitting a single binary parameter between K+ and the IL-ions to the IL solubility in K3PO4 aqueous solutions. Based on this approach, the description of anion-specific salting-out effects of the remaining potassium salts was found to be in good agreement with experimental data. Remarkably, ePC-SAFT is even able to predict the salting-in effect induced by K2HPO4, based on the single K+/IL-ions binary parameter which was fitted to an exclusively salting-out effect promoted by K3PO4. Finally, ePC-SAFT was applied to predict the influence of other sodium salts on the [C4C1im][NTf2] solubility in water, with experimental data taken from literature, leading to an excellent description of the liquid–liquid phase behaviour. PMID:26575280
Directory of Open Access Journals (Sweden)
Harald Lachnit
Full Text Available In four human learning experiments (Pavlovian skin conductance, causal learning, speeded classification task, we evaluated several associative learning theories that assume either an elemental (modified unique cue model and Harris' model or a configural (Pearce's configural theory and an extension of it form of stimulus processing. The experiments used two modified patterning problems (A/B/C+, AB/BC/AC+ vs. ABC-; A+, BC+ vs. ABC-. Pearce's configural theory successfully predicted all of our data reflecting early stimulus processing, while the predictions of the elemental theories were in accord with all of our data reflecting later stages of stimulus processing. Our results suggest that the form of stimulus representation depends on the amount of time available for stimulus processing. Our findings highlight the necessity to investigate stimulus processing during conditioning on a finer time scale than usually done in contemporary research.
Classes and Theories of Trees Associated with a Class Of Linear Orders
DEFF Research Database (Denmark)
Goranko, Valentin; Kellerman, Ruaan
2011-01-01
these classes of trees and between their corresponding first-order theories. We then obtain some general results about the axiomatization of the first-order theories of some of these classes of trees in terms of the first-order theory of the generating class C, and indicate the problems obstructing such general...... results for the other classes. These problems arise from the possible existence of nondefinable paths in trees, that need not satisfy the first-order theory of C, so we have started analysing first order definable and undefinable paths in trees....
de Bilde, Jerissa; Vansteenkiste, Maarten; Lens, Willy
2011-01-01
The present cross-sectional research examined a process underlying the positive association between holding an extended future time perspective (FTP) and learning outcomes through the lens of self-determination theory. High school students and university students (N = 275) participated in the study. It was found that students with an extended FTP…
Reuveni, Yehudit; Werner, Perla
2015-01-01
The purpose of this study was to investigate the factors associated with teenagers' willingness to volunteer with elderly persons using an expanded model of the Theory of Planned Behavior (TPB). Participants consisted of 258 ninth-grade students at a large high school in the northern part of Israel. Participants completed a structured…
Energy Technology Data Exchange (ETDEWEB)
Schaefer, B.; Lambert, S.M.; Song, Y.; Prausnitz, J.M.
1994-10-01
Goal of this work is the extension of a Perturbed-Hard-Sphere-Chain equation of state (PHSC EOS) to systems containing strong polar components. Three different types of association models (ten Brinke/Karasz, SAFI, modified Veytsman) were used to calculate the contribution of specific interactions like hydrogen bonding to thermodynamic quantities. Pure component parameters obtained from regression of temperature dependent density and vapor pressure data allow the prediction of VLE and LLE data. The results of simple fluids and polymer solutions were compared with experimental data. The SAFT and the modified Veytsman extension give similar results for pure fluids and mixtures with components of similar segment size. Differences increase with increasing difference of segment size.
Mahajan, Vikas; Rahman, Asad; Tarawneh, Amjad; Sant'anna, Guilherme Mendes
2011-01-01
In newborns, the presence of liver fluid collection is a rare event. The reported cases are isolated or described over long periods. Within four months, five neonates were diagnosed with liver fluid collection from safety occurrence reports. Clinical, laboratory and radiological data were extracted from medical records. The definite diagnosis was made by ultrasound. Four of the patients were preterm, male and had very low birth weights. The osmolality of the infused solution was within the acceptable range. Investigations revealed that the use of a new brand of umbilical vein catheter introduced in the neonatal intensive care unit, one month before the first case, was associated with this cluster. Low positioning of the umbilical vein catheter tip appeared to be a second contributory factor. Neonatal practitioners may benefit from the present report when facing the occurrence of similar lesions. PMID:22211066
Energy Technology Data Exchange (ETDEWEB)
Lekia, S.D.L. (Unocal Production and Development Technology, Brea, CA (United States)); Evans, R.D. (Univ. of Oklahoma, Norman, OK (United States))
1995-02-01
Equations are derived from first principles for predicting the behavior of sucker-rod pumping systems including the effects of rod and fluid dynamics, and kinematics of the surface pumping unit. Equations are also developed for both incompressible and slightly compressible fluid flow scenarios. The resulting composite rod and fluid dynamic model is solved using the MacCormack Explicit Numerical Scheme. Example problems used to validate this model are presented in a companion paper.
McLean, Samuel A.; Williams, David A.; Stein, Phyllis K.; Harris, Richard E.; Lyden, Angela K; Whalen, Gail; Park, Karen M; Liberzon, Israel; Sen, Ananda; Gracely, Richard H.; Baraniuk, James N.; Clauw, Daniel J
2006-01-01
Previous studies have identified stress system dysregulation in fibromyalgia (FM) patients; such dysregulation may be involved in the generation and/or maintenance of pain and other symptoms. Corticotropin-releasing factor (CRF) is the principal known central nervous system mediator of the stress response; however, to date no studies have examined cerebrospinal fluid (CSF) CRF levels in patients with FM. The relationship between CSF CRF level, heart rate variability (HRV), and pain, fatigue, ...
Equations of State: From the Ideas of van der Waals to Association Theories
DEFF Research Database (Denmark)
Kontogeorgis, Georgios; Economou, Ioannis G.
2010-01-01
equations of state are sensitive to the mixing and combining rules used. Moreover, it is shown that previously reported deficiencies for size-asymmetric systems are more related to the van der Waals one fluid mixing rules used rather than the functionality of the cubic equation of state itself. Improved...
Directory of Open Access Journals (Sweden)
Shilin Zhao
2013-01-01
Full Text Available Body fluid proteome is the most informative proteome from a medical viewpoint. But the lack of accurate quantitation method for complicated body fluid limited its application in disease research and biomarker discovery. To address this problem, we introduced a novel strategy, in which SILAC-labeled mouse serum was used as internal standard for human serum and urine proteome analysis. The SILAC-labeled mouse serum was mixed with human serum and urine, and multidimensional separation coupled with tandem mass spectrometry (IEF-LC-MS/MS analysis was performed. The shared peptides between two species were quantified by their SILAC pairs, and the human-only peptides were quantified by mouse peptides with coelution. The comparison for the results from two replicate experiments indicated the high repeatability of our strategy. Then the urine from Immunoglobulin A nephropathy patients treated and untreated was compared by this quantitation strategy. Fifty-three peptides were found to be significantly changed between two groups, including both known diagnostic markers for IgAN and novel candidates, such as Complement C3, Albumin, VDBP, ApoA,1 and IGFBP7. In conclusion, we have developed a practical and accurate quantitation strategy for comparison of complicated human body fluid proteome. The results from such strategy could provide potential disease-related biomarkers for evaluation of treatment.
International Nuclear Information System (INIS)
Boundary effects are investigated for fluids with internal orientational degrees of freedom such as molecular liquids, thermotropic and lyotropic liquid crystals, and polymeric fluids. The orientational degrees of freedom are described by the second rank alignment tensor which is related to the birefringence. We use a standard model to describe the orientational dynamics in the presence of flow, the momentum balance equations, and a constitutive law for the pressure tensor to describe our system. In the spirit of irreversible thermodynamics, boundary conditions are formulated for the mechanical slip velocity and the flux of the alignment. They are set up such that the entropy production at the wall inferred from the entropy flux is positive definite. Even in the absence of a true mechanical slip, the coupling between orientation and flow leads to flow profiles with an apparent slip. This has consequences for the macroscopically measurable effective velocity. In analytical investigations, we consider the simplified case of an isotropic fluid in the Newtonian and stationary flow regime. For special geometries such as plane and cylindrical Couette flow, plane Poiseuille flow, and a flow down an inclined plane, we demonstrate explicitly how the boundary conditions lead to an apparent slip. Furthermore, we discuss the dependence of the effective viscosity and of the effective slip length on the model parameters
Neely, Benjamin A; Soper, Jennifer L; Gulland, Frances M D; Bell, P Darwin; Kindy, Mark; Arthur, John M; Janech, Michael G
2015-12-01
Proteomic studies including marine mammals are rare, largely due to the lack of fully sequenced genomes. This has hampered the application of these techniques toward biomarker discovery efforts for monitoring of health and disease in these animals. We conducted a pilot label-free LC-MS/MS study to profile and compare the cerebrospinal fluid from California sea lions with domoic acid toxicosis (DAT) and without DAT. Across 11 samples, a total of 206 proteins were identified (FDRlions with DAT: complement C3, complement factor B, dickkopf-3, malate dehydrogenase 1, neuron cell adhesion molecule 1, gelsolin, and neuronal cell adhesion molecule. Immunoblot analysis found reelin to be depressed in the cerebrospinal fluid from California sea lions with DAT. Mice administered domoic acid also had lower hippocampal reelin protein levels suggesting that domoic acid depresses reelin similar to kainic acid. In summary, proteomic analysis of cerebrospinal fluid in marine mammals is a useful tool to characterize the underlying molecular pathology of neurodegenerative disease. All MS data have been deposited in the ProteomeXchange with identifier PXD002105 (http://proteomecentral.proteomexchange.org/dataset/PXD002105).
Ko, N-Y; Yeh, S-H; Tsay, S-L; Ma, H-J; Chen, C-H; Pan, S-M; Feng, M-C; Chiang, M-C; Lee, Y-W; Chang, L-H; Jang, J-F
2011-04-01
Nurses are at significant risk from occupationally acquired bloodborne virus infections following a needlestick and sharps injury. This study aimed to apply the theory of planned behaviour (TPB) to predict nurses' intention to comply with occupational post-exposure management. A cross-sectional survey was applied to select registered nurses who worked in human immunodeficiency virus (HIV)-designated hospitals. An anonymous, self-administered questionnaire based on the TPB was distributed to 1630 nurses and 1134 (69.5%) questionnaires were returned. From these, a total of 802 nurses (71%) reported blood and body fluid exposure incidents during 2003-2005 and this group was used for analysis. Only 44.6% of the 121 exposed nurses who were prescribed post-exposure prophylaxis (PEP) by infectious disease doctors returned to the clinic for interim monitoring, and only 56.6% of exposed nurses confirmed their final serology status. Structural equation modelling was used to test the TPB indicating perceived behavioural control (the perception of the difficulty or ease of PEP management, β=0.58), subjective norm (the perception of social pressure to adhere to PEP, β=0.15), and attitudes (β=0.12) were significant direct effects on nurses' intention to comply with post-exposure management. The hypothesised model test indicated that the model fitted with the expected relationships and directions of theoretical constructs [χ(2) (14, N=802)=23.14, P=0.057, GFI=0.987, RMSEA=0.039]. The TPB model constructs accounted for 54% of the variance in nurses' intention to comply with post-exposure management. The TPB is an appropriate model for predicting nurses' intention to comply with post-exposure management. Healthcare facilities should have policies to decrease the inconvenience of follow-up to encourage nurses to comply with post-exposure management. PMID:21276639
Association of theory of mind with social relations and child's social competence
Directory of Open Access Journals (Sweden)
Nuša Skubic
2012-10-01
Full Text Available The article reviews and evaluates the findings from the research in the field of theory of mind; how the theory of mind is connected to social relationships and how a child's social competence reflects his/hers theory of mind. It points to those factors that contribute most to considerable individual differences among children when developing a theory of mind and it stresses out the reciprocity of effects between child's social understanding and social relations with others. Positive factors for developing a theory of mind are first of all child's early quality experiences about mental states which predict a child's performance on the false belief test later on. Social-economic status, parental behavior and talk (for example appropriate use of mental states and appropriate disciplining of a child and presence of sibling of appropriate age (usually older one with whom a child develops a quality relationship are most important family factors for theory of mind development. The role of peers is most important factor outside the family, emphasized by studies. In accordance with these factors a child develops more or less successfully his/hers social understanding which plays an important part in his/hers daily life. Children with well developed theory of mind can use it in a pro-social way, or it can serve proactive or reactive aggression when children use their understanding of others as a way of manipulating and bullying, especially inside their peer group. Poorly developed theory of mind can prove to be a risk factor especially in a bad family situation, while a well developed theory of mind can play a protective role in child's development. The article points out some of the deficiencies of reviewed studies and proposes options for more complex future research of child's theory of mind.
Beyond generalized Proca theories
Heisenberg, Lavinia; Tsujikawa, Shinji
2016-01-01
We consider higher-order derivative interactions beyond second-order generalized Proca theories that propagate only the three desired polarizations of a massive vector field besides the two tensor polarizations from gravity. These new interactions follow the similar construction criteria to those arising in the extension of scalar-tensor Horndeski theories to Gleyzes-Langlois-Piazza-Vernizzi (GLPV) theories. On the maximally symmetric space-time, we perform the Hessian and Hamiltonian analysis and show the presence of a second-class constraint that removes the would-be ghost associated with the temporal component of the vector field. Furthermore, we study the behavior of linear perturbations on top of the homogeneous and isotropic cosmological background in the presence of a matter perfect fluid and find the same number of propagating degrees of freedom as in generalized Proca theories. Moreover, we obtain the conditions for the avoidance of ghosts and Laplacian instabilities of tensor, vector, and scalar per...
Lee, Tien-Rein
2002-06-01
Chinese believe that Feng-shui, Ch'i, Tao, Yin and Yang are major components rooted in Chinese culture. Many people know life has to balance and harmonize with nature and the universe through the Five-essence. Ancient wisdom is successfully interwoven with mankind and the natural world. Elements such as orientation, season, color, sound, facial organs, viscera, stars, and numbers can be associated with life through the Five-essence Theory. Since color is one of the major components of the Five-essence Theory, everything in our life can be associated with colors through a conjoined covering process. Color selection process is part of the interaction between human beings and the universe. Depending on the achievement one is pursuing, the Five- essence Theory model can be treated as an interface between destiny and human beings. This study reports how life is associated with Chinese Five-essence based paradigms. Models were used to explain how Chinese utilize Five-essence Theory to select colors in their daily lives.
Institute of Scientific and Technical Information of China (English)
常美; 徐国宾
2013-01-01
The minimum rate of energy dissipation has been rigorously proved by theory, but lacking of a large number of measured data and numerical simulation to proof it is a problem. RNG k-ε turbulence model and GMO model of Flow3D are applied to simulate fluid motion in a straight rectangular flume. Selecting the fluid between different sections as a system to study, the instantaneous rate of energy dissipation per unit fluid volume of the system is calculated. The results show that the fluid motion in the rectangular tank follows the theory of minimum rate of energy dissipation.%最小能耗率原理发展至今,已有严密的理论证明,但缺少实测数据和数值模拟的验证.本文采用Flow3D中RNG k-ε紊流模型结合GMO法对顺直矩形水槽内的水流运动进行了数值模拟研究,通过选取不同断面之间的水流为研究系统,计算了各个时刻系统的单位体积水流能耗率变化.结果表明,矩形水槽内的水流运动确实遵循最小能耗率原理.
Exarchos, Dimitris
2014-01-01
In lieu of an abstract, here is a brief excerpt of the content: Comprising research spanning over a decade, A Theory of Music Analysis constitutes a comprehensive account and a culmination of Dora A. Hanninen’s work to date. To the extent that no theory of music is independent of analysis, this work is indispensable as a theory of analysis. The main (philosophical) concern of the book is how to create a precise analytical language, one that can secure a credible interpretation; intertwined...
Sellgren, CM; Kegel, ME; Bergen, SE; Ekman, CJ; Olsson, S; Larsson, M; Vawter, MP; Backlund, L; Sullivan, PF; Sklar, P; Smoller, JW; Magnusson, PKE; Hultman, CM; Walther-Jallow, L; Svensson, CI; Lichtenstein, P; Schalling, M; Engberg, G; Erhardt, S; Landén, M
2016-01-01
Elevated cerebrospinal fluid (CSF) levels of the glia-derived N-methyl-D-aspartic acid receptor antagonist kynurenic acid (KYNA) have consistently been implicated in schizophrenia and bipolar disorder. Here, we conducted a genome-wide association study based on CSF KYNA in bipolar disorder and found support for an association with a common variant within 1p21.3. After replication in an independent cohort, we linked this genetic variant—associated with reduced SNX7 expression—to positive psychotic symptoms and executive function deficits in bipolar disorder. A series of post-mortem brain tissue and in vitro experiments suggested SNX7 downregulation to result in a caspase-8-driven activation of interleukin-1β and a subsequent induction of the brain kynurenine pathway. The current study demonstrates the potential of using biomarkers in genetic studies of psychiatric disorders, and may help to identify novel drug targets in bipolar disorder. PMID:23459468
Sellgren, C M; Kegel, M E; Bergen, S E; Ekman, C J; Olsson, S; Larsson, M; Vawter, M P; Backlund, L; Sullivan, P F; Sklar, P; Smoller, J W; Magnusson, P K E; Hultman, C M; Walther-Jallow, L; Svensson, C I; Lichtenstein, P; Schalling, M; Engberg, G; Erhardt, S; Landén, M
2016-01-01
Elevated cerebrospinal fluid (CSF) levels of the glia-derived N-methyl-D-aspartic acid receptor antagonist kynurenic acid (KYNA) have consistently been implicated in schizophrenia and bipolar disorder. Here, we conducted a genome-wide association study based on CSF KYNA in bipolar disorder and found support for an association with a common variant within 1p21.3. After replication in an independent cohort, we linked this genetic variant—associated with reduced SNX7 expression—to positive psychotic symptoms and executive function deficits in bipolar disorder. A series of post-mortem brain tissue and in vitro experiments suggested SNX7 downregulation to result in a caspase-8-driven activation of interleukin-1β and a subsequent induction of the brain kynurenine pathway. The current study demonstrates the potential of using biomarkers in genetic studies of psychiatric disorders, and may help to identify novel drug targets in bipolar disorder. PMID:26666201
The distribution of prime numbers and associated problems in number theory
International Nuclear Information System (INIS)
Some problems in number theory, namely the gaps between consecutive primes, the distribution of primes in arithmetic progressions, Brun-Titchmarsh theorem, Fermat's last theorem, The Thue equation, the gaps between square-free numbers are discussed
O'Brien, Charles E.; Giovannelli, Donato; Govenar, Breea; Luther, George W.; Lutz, Richard A.; Shank, Timothy M.; Vetriani, Costantino
2015-11-01
At deep-sea hydrothermal vents, reduced, super-heated hydrothermal fluids mix with cold, oxygenated seawater. This creates temperature and chemical gradients that support chemosynthetic primary production and a biomass-rich community of invertebrates. In late 2005/early 2006 an eruption occurred on the East Pacific Rise at 9°50‧N, 104°17‧W. Direct observations of the post-eruptive diffuse-flow vents indicated that the earliest colonizers were microbial biofilms. Two cruises in 2006 and 2007 allowed us to monitor and sample the early steps of ecosystem recovery. The main objective of this work was to characterize the composition of microbial biofilms in relation to the temperature and chemistry of the hydrothermal fluids and the observed patterns of megafaunal colonization. The area selected for this study had local seafloor habitats of active diffuse flow (in-flow) interrupted by adjacent habitats with no apparent expulsion of hydrothermal fluids (no-flow). The in-flow habitats were characterized by higher temperatures (1.6-25.2 °C) and H2S concentrations (up to 67.3 μM) than the no-flow habitats, and the microbial biofilms were dominated by chemosynthetic Epsilonproteobacteria. The no-flow habitats had much lower temperatures (1.2-5.2 °C) and H2S concentrations (0.3-2.9 μM), and Gammaproteobacteria dominated the biofilms. Siboglinid tubeworms colonized only in-flow habitats, while they were absent at the no-flow areas, suggesting a correlation between siboglinid tubeworm colonization, active hydrothermal flow, and the composition of chemosynthetic microbial biofilms.
Physics through the 1990s: Plasmas and fluids
1986-01-01
The volume contains recommendations for programs in, and government support of, plasma and fluid physics. Four broad areas are covered: the physics of fluids, general plasma physics, fusion, and space and astrophysical plasmas. In the first section, the accomplishments of fluid physics and a detailed review of its sub-fields, such as combustion, non-Newtonian fluids, turbulence, aerodynamics, and geophysical fluid dynamics, are described. The general plasma physics section deals with the wide scope of the theoretical concepts involved in plasma research, and with the machines; intense beam systems, collective and laser-driven accelerators, and the associated diagnostics. The section on the fusion plasma research program examines confinement and heating systems, such as Tokamaks, magnetic mirrors, and inertial-confinement systems, and several others. Finally, theory and experiment in space and astrophysical plasma research is detailed, ranging from the laboratory to the solar system and beyond. A glossary is included.
DEFF Research Database (Denmark)
Andreou, Dimitrios; Saetre, Peter; Werge, Thomas;
2010-01-01
Tryptophan hydroxylase (TPH) is the rate-limiting enzyme in serotonin synthesis. We investigated possible relationships between five TPH1 gene polymorphisms and cerebrospinal fluid (CSF) concentrations of the major serotonin metabolite 5-hydroxyindoleacetic acid (5-HIAA), the major dopamine...... metabolite homovanillic acid (HVA), and the major norepinephrine metabolite 3-methoxy-4-hydroxyphenylglycol (MHPG) in healthy volunteers (n=132). The G-allele of the TPH1 rs4537731 (A-6526G) polymorphism was associated with 5-HIAA and HVA, but not MHPG concentrations. None of the other four TPH1...
Durazzo, Timothy C; Korecka, Magdalena; Trojanowski, John Q; Weiner, Michael W; O' Hara, Ruth; Ashford, John W; Shaw, Leslie M
2016-07-25
Neurodegenerative diseases and chronic cigarette smoking are associated with increased cerebral oxidative stress (OxS). Elevated F2-isoprostane levels in biological fluid is a recognized marker of OxS. This study assessed the association of active cigarette smoking with F2-isoprostane in concentrations in cognitively-normal elders (CN), and those with mild cognitive impairment (MCI) and probable Alzheimer's disease (AD). Smoking and non-smoking CN (n = 83), MCI (n = 164), and probable AD (n = 101) were compared on cerebrospinal fluid (CSF) iPF2α-III and 8,12, iso-iPF2α-VI F2-isoprostane concentrations. Associations between F2-isoprostane levels and hippocampal volumes were also evaluated. In CN and AD, smokers had higher iPF2α-III concentration; overall, smoking AD showed the highest iPF2α-III concentration across groups. Smoking and non-smoking MCI did not differ on iPF2α-III concentration. No group differences were apparent on 8,12, iso-iPF2α-VI concentration, but across AD, higher 8,12, iso-iPF2α-VI level was related to smaller left and total hippocampal volumes. Results indicate that active cigarette smoking in CN and probable AD is associated with increased central nervous system OxS. Further investigation of factors mediating/moderating the absence of smoking effects on CSF F2-isoprostane levels in MCI is warranted. In AD, increasing magnitude of OxS appeared to be related to smaller hippocampal volume. This study contributes additional novel information to the mounting body of evidence that cigarette smoking is associated with adverse effects on the human central nervous system across the lifespan. PMID:27472882
Kannel, J. W.; Merriman, T. L.; Stockwell, R. D.; Dufrane, K. F.
1983-01-01
The feasibility of measuring elastohydrodynamic (EHD) films as formed with a cryogenic (LN2) fluid is evaluated. Modifications were made to an existing twin disk EHD apparatus to allow for disk lubrication with liquid nitrogen. This disk apparatus is equipped with an X-ray system for measuring the thickness of any lubricant film that is formed between the disks. Several film thickness experiments were conducted with the apparatus which indicate that good lubrication films are filmed with LN2. In addition to the film thickness studies, failure analyses of three bearings were conducted. The HPOTP turbine end bearings had experienced axial loads of 36,000 to 44,000 N (8,000 to 10,000 lb). High continuous radial loads were also experienced, which were most likely caused by thermal growth of the inner race. The resulting high internal loads caused race spalling and ball wear to occur.
Interfacial instabilities in vibrated fluids
Porter, Jeff; Laverón-Simavilla, Ana; Tinao Perez-Miravete, Ignacio; Fernandez Fraile, Jose Javier
2016-07-01
that leads to splitting (fluid separation). We investigate the interaction of these prominent interfacial instabilities in the absence of gravity, concentrating on harmonically vibrated rectangular containers of fluid. We compare vibroequilibria theory with direct numerical simulations and consider the effect of surfaces waves, which can excite sloshing motion of the vibroequilibria. We systematically investigate the saddle-node bifurcation experienced by a symmetric singly connected vibroequilibria solution, for sufficiently deep containers, as forcing is increased. Beyond this instability, the fluid rapidly separates into (at least) two distinct masses. Pronounced hysteresis is associated with this transition, even in the presence of gravity. The interaction of vibroequilibria and frozen waves is investigated in two-fluid systems. Preparations for a parabolic flight experiment on fluids vibrated at high frequencies are discussed.
Devine, Rory T.; White, Naomi; Ensor, Rosie; Hughes, Claire
2016-01-01
The vast majority of studies on theory of mind (ToM) have focused on the preschool years. Extending the developmental scope of ToM research presents opportunities to both reassess theoretical accounts of ToM and test its predictive utility. The twin aims of this longitudinal study were to examine developmental relations between ToM, executive…
International Nuclear Information System (INIS)
A study is made of a scale model in three dimensions of a guiding center plasma within the purview of gyroelastic (also known as finite gyroradius-near theta pinch) magnetohydrodynamics. The (nonlinear) system sustains a particular symmetry called isorrhopy which permits the decoupling of fluid modes from drift modes. Isorrhopic equilibria are analyzed within the framework of geometrical optics resulting in (local) dispersion relations and ray constants. A general scheme is developed to evolve an arbitrary linear perturbation of a screwpinch equilibrium as an invertible integral transform (over the complete set of generalized eigenfunctions defined naturally by the equilibrium). Details of the structure of the function space and the associated spectra are elucidated. Features of the (global) dispersion relation owing to the presence of gyroelastic stabilization are revealed. An energy principle is developed to study the stability of the tubular screwpinch
Institute of Scientific and Technical Information of China (English)
王宏伦; 姚鹏; 梁宵; 吕文涛
2015-01-01
This paper introduces a novel path planning algorithm for Unmanned Aerial Vehicle ( UAV ) based on theory of fluid avoiding obstacles. To the problem of path planning which aims at the global optimum, not only the influence of terrain constraints on path safety but also the performance constraints of UAV should be taken into con-sideration, thus a feasible and smooth path will be planned in the three-dimensional space. The computation com-plexity and the path quality by traditional algorithms are usually unsatisfactory, hence we propose the method in-spired by the phenomenon that water can avoid rocks and reach the destination. The common features between this phenomenon and the path planning problem are extracted and analyzed, and then the mathematical model generali-zing the phenomenon is constructed on the basis of theory of fluid mechanics. By selecting the optimal streamline from the fluid field under the evaluation index, the three-dimensional optimal path under flight and environment con-straints is obtained eventually.
Directory of Open Access Journals (Sweden)
John S K Kauwe
Full Text Available Recent genome-wide association studies of Alzheimer's disease (AD have identified variants in BIN1, CLU, CR1 and PICALM that show replicable association with risk for disease. We have thoroughly sampled common variation in these genes, genotyping 355 variants in over 600 individuals for whom measurements of two AD biomarkers, cerebrospinal fluid (CSF 42 amino acid amyloid beta fragments (Aβ(42 and tau phosphorylated at threonine 181 (ptau(181, have been obtained. Association analyses were performed to determine whether variants in BIN1, CLU, CR1 or PICALM are associated with changes in the CSF levels of these biomarkers. Despite adequate power to detect effects as small as a 1.05 fold difference, we have failed to detect evidence for association between SNPs in these genes and CSF Aβ(42 or ptau(181 levels in our sample. Our results suggest that these variants do not affect risk via a mechanism that results in a strong additive effect on CSF levels of Aβ(42 or ptau(181.
DEFF Research Database (Denmark)
Arya, Alay; Liang, Xiaodong; von Solms, Nicolas;
2016-01-01
Asphaltene precipitation has been one of the major problems in the oil industry, and its modeling is still believed to be a quite complex issue due to the different characteristics of thousands of heavy components in crude oil. There have been several attempts to model asphaltene precipitation us...
Microforces and the Theory of Solute Transport
Fried, Eliot; Sellers, Shaun
1999-01-01
A generalized continuum framework for the theory of solute transport in fluids is proposed and systematically developed. This framework rests on the introduction of a generic force balance for the solute, a balance distinct from the macroscopic momentum balance associated with the mixture. Special forms of such a force balance have been proposed and used going back at least as far as Nernst's 1888 theory of diffusion. Under certain circumstances, this force balance yields a Fickian constituti...
Drazin, Philip
1987-01-01
Outlines the contents of Volume II of "Principia" by Sir Isaac Newton. Reviews the contributions of subsequent scientists to the physics of fluid dynamics. Discusses the treatment of fluid mechanics in physics curricula. Highlights a few of the problems of modern research in fluid dynamics. Shows that problems still remain. (CW)
Energy Technology Data Exchange (ETDEWEB)
Slawomirski, M.R.
1979-01-01
An examination is made of the flow of viscoplastic fluids in the space between two coaxial pipes with regard for rotation of the inner pipe. An analytical solution is provided for the task to determine the nature of distribution of flow velocity of the drilling fluid in the annular space and distribution of angular velocities in the flow. A relationship is obtained between the angular velocity of the drilling string and the torque acting on it. In this case, cases are examined where there is no flow nucleus, where the flow nucleus occupies the entire section of the annular space and an intermediate case where the flow nucleus only occupies part of the annular space limited by a certain radius. The solutions are given for different rheological models: Bingam, Khershel-Balkli and Kasson.
Lim, Hyun Jeong; Kim, Min Ju; Kim, Kyung Won
2015-01-01
BACKGROUND/OBJECTIVES Use of nutrition labels in food selection is recommended for consumers. The aim of this study is to examine factors, mainly beliefs explaining nutrition label use in female college students based on the Theory of Planned Behavior (TPB). SUBJECTS/METHODS The subjects were female college students from a university in Seoul, Korea. The survey questionnaire was composed of items examining general characteristics, nutrition label use, behavioral beliefs, normative beliefs, co...
Laura Germine; Dunn, Erin C.; McLaughlin, Katie A.; Smoller, Jordan W.
2015-01-01
People vary substantially in their ability to acquire and maintain social ties. Here, we use a combined epidemiological and individual differences approach to understand the childhood roots of adult social cognitive functioning. We assessed exposure to 25 forms of traumatic childhood experiences in over 5000 adults, along with measures of face discrimination, face memory, theory of mind, social motivation, and social support. Retrospectively-reported experiences of parental maltreatment in ch...
Cognitive Factors and Family Structure Associated with Theory of Mind Development in Young Children.
Jenkins, Jennifer M.; Astington, Janet Wilde
1996-01-01
Examined factors associated with individual variation in false belief understanding in three- to five-year olds. Found that family size was strongly associated with false belief understanding in children who were less competent linguistically, suggesting that the presence of siblings can compensate for slower language development in developing…
Bradas, James C.; Fennelly, Alphonsus J.; Smalley, Larry L.
1987-01-01
It is shown that a generalized (or 'power law') inflationary phase arises naturally and inevitably in a simple (Bianchi type-I) anisotropic cosmological model in the self-consistent Einstein-Cartan gravitation theory with the improved stress-energy-momentum tensor with the spin density of Ray and Smalley (1982, 1983). This is made explicit by an analytical solution of the field equations of motion of the fluid variables. The inflation is caused by the angular kinetic energy density due to spin. The model further elucidates the relationship between fluid vorticity, the angular velocity of the inertially dragged tetrads, and the precession of the principal axes of the shear ellipsoid. Shear is not effective in damping the inflation.
Solvation phenomena in association theories with applications to oil & gas and chemical industries
DEFF Research Database (Denmark)
Kontogeorgis, Georgios; Folas, Georgios; Muro Sunè, Nuria;
2008-01-01
with two non self-associating compounds may exhibit solvation specifically due to hydrogen bonding or more generally due to Lewis acid-Lewis base interactions. As examples can be mentioned mixtures with polar compounds (water, glycols...) and aromatic hydrocarbons and aqueous ether or ester solutions...... the scientific point of view, solvation phenomena are also very significant because they are present in different types of mixtures and not just those containing two self-associating compounds e.g. water with alcohols or glycols. Mixtures with only one self-associating compound and in some cases even mixtures...
Nonlinear free vibration of single walled Carbone NanoTubes conveying fluid
Directory of Open Access Journals (Sweden)
Azrar A.
2014-04-01
Full Text Available Nonlinear free vibration of single-walled carbon nanotubes (CNTs conveying fluid are modeled and numerically simulated based on von Kármán geometric nonlinearity and Eringen’s nonlocal elasticity theory. The CNTs are modelled as nanobeams where the effects of transverse shear deformation and rotary inertia are considered within the framework of Timoshenko beam theory. The governing equations and boundary conditions are derived using the Hamilton’s principle and the nonlinear equation of motion is solved by the Galerkin’s method. The small scale parameter and the fluid-tube interaction effects on the dynamic behaviours of the CNT-fluid system as well as the instabilities induced by the fluid-velocity can be investigated. The critical fluid-velocity and frequency-amplitude relationships as well as the flutter and divergence instability types and the associated time responses are obtained based on the presented methodological approach.
Fluids in the continental crust
Yardley, BWD; Bodnar, RJ
2014-01-01
Fluids play a critical role in the geochemical and geodynamical evolution of the crust, and fluid flow is the dominant process associated with mass and energy transport in the crust. In this Perspectives, we summarise the occurrence, properties and role that fluids play in crustal processes, as well as how geoscientists’ understanding of these various aspects of fluids have evolved during the past century and how this evolution in thinking has influenced our own research careers. Despite the ...
An associative-activation theory of children's and adults' memory illusions
Howe, M. L.; Wimmer, M. C.; Gagnon, N.; Plumpton, S.
2009-01-01
The effects of associative strength and gist relations on rates of children’s and adults’ true and false memories were examined in three experiments. Children aged 5–11 and university-aged adults participated in a standard Deese/Roediger–McDermott false memory task using DRM and category lists in two experiments and in the third, children memorized lists that differed in associative strength and semantic cohesion. In the first two experiments, half of the participants were primed before list ...
Contributions to the Theory of Measures of Association for Ordinal Variables
Ekström, Joakim
2009-01-01
In this thesis, we consider measures of association for ordinal variables from a theoretical perspective. In particular, we study the phi-coefficient, the tetrachoric correlation coefficient and the polychoric correlation coefficient. We also introduce a new measure of association for ordinal variables, the empirical polychoric correlation coefficient, which has better theoretical properties than the polychoric correlation coefficient, including greatly enhanced robustness. In the first artic...
Coupled mode theory approach to depolarization associated with propagation in turbulent media
Crosignani, B.; di Porto, P.; Clifford, Steven F.
1988-06-01
Marcuse's (1974) coupled-mode theory is invoked in the present consideration of the problem of light depolarization in a turbulent atmosphere, in order to allow the evaluation of the depolarization ratio for a plane wave and comparison of its expression with that obtained in the frame of two distinct approaches predicting different behaviors. It is found that both approaches yield the same result when calculated to the same order in both of the relevant smallness parameters, thereby resolving a long-standing controversy.
Directory of Open Access Journals (Sweden)
Kavitha Kothur
Full Text Available Myelin oligodendrocyte glycoprotein antibody (MOG Ab associated demyelination represents a subgroup of autoimmune demyelination that is separate from multiple sclerosis and aquaporin 4 IgG-positive NMO, and can have a relapsing course. Unlike NMO and MS, there is a paucity of literature on immunopathology and CSF cytokine/chemokines in MOG Ab associated demyelination.To study the differences in immunopathogenesis based on cytokine/chemokine profile in MOG Ab-positive (POS and -negative (NEG groups.We measured 34 cytokines/chemokines using multiplex immunoassay in CSF collected from paediatric patients with serum MOG Ab POS [acute disseminated encephalomyelitis (ADEM = 8, transverse myelitis (TM = 2 n = 10] and serum MOG Ab NEG (ADEM = 5, TM = 4, n = 9 demyelination. We generated normative data using CSF from 20 non-inflammatory neurological controls.The CSF cytokine and chemokine levels were higher in both MOG Ab POS and MOG Ab NEG demyelination groups compared to controls. The CSF in MOG Ab POS patients showed predominant elevation of B cell related cytokines/chemokines (CXCL13, APRIL, BAFF and CCL19 as well as some of Th17 related cytokines (IL-6 AND G-CSF compared to MOG Ab NEG group (all p<0.01. In addition, patients with elevated CSF MOG antibodies had higher CSF CXCL13, CXCL12, CCL19, IL-17A and G-CSF than patients without CSF MOG antibodies.Our findings suggest that MOG Ab POS patients have a more pronounced CNS inflammatory response with elevation of predominant humoral associated cytokines/chemokines, as well as some Th 17 and neutrophil related cytokines/chemokines suggesting a differential inflammatory pathogenesis associated with MOG antibody seropositivity. This cytokine/chemokine profiling provides new insight into disease pathogenesis, and improves our ability to monitor inflammation and response to treatment. In addition, some of these molecules may represent potential immunomodulatory targets.
Loeffler, David A; Klaver, Andrea C; Coffey, Mary P; Aasly, Jan O; LeWitt, Peter A
2016-01-01
Age-associated declines in protein homeostasis mechanisms ("proteostasis") are thought to contribute to age-related neurodegenerative disorders. The increased oxidative stress which occurs with aging can activate a key proteostatic process, chaperone-mediated autophagy. This study investigated age-related alteration in cerebrospinal fluid (CSF) concentrations of heat shock 70-kDa protein 8 (HSPA8), a molecular chaperone involved in proteostatic mechanisms including chaperone-mediated autophagy, and its associations with indicators of oxidative stress (8-hydroxy-2'-deoxyguanosine [8-OHdG] and 8-isoprostane) and total anti-oxidant capacity. We examined correlations between age, HSPA8, 8-OHdG, 8-isoprostane, and total antioxidant capacity (TAC) in CSF samples from 34 healthy subjects ranging from 20 to 75 years of age. Age was negatively associated with HSPA8 (ρ = -0.47; p = 0.005). An age-related increase in oxidative stress was indicated by a positive association between age and 8-OHdG (ρ = 0.61; p = 0.0001). HSPA8 was moderately negatively associated with 8-OHdG (ρ = -0.58; p = 0.0004). Age and HSPA8 were weakly associated with 8-isoprostane and TAC (range of ρ values: -0.15 to 0.16). Our findings in this exploratory study suggest that during healthy aging, CSF HSPA8 may decrease, perhaps due in part to an increase in oxidative stress. Our results also suggest that 8-OHdG may be more sensitive than 8-isoprostane for measuring oxidative stress in CSF. Further studies are indicated to determine if our findings can be replicated with a larger cohort, and if the age-related decrease in HSPA8 in CSF is reflected by a similar change in the brain. PMID:27507943
Petts, D. C.; Stachel, T.; Stern, R. A.; Hunt, L.; Fomradas, G.
2016-02-01
-crystal cuboid and fibrous rim data were observed, including a consistent ~1.3 ‰ offset in δ 15N values between the two growth types. This bimodal N-isotope distribution is interpreted as formation from separate parental fluids, associated with distinct nitrogen sources. The bimodal N-isotope distribution could also be explained by differences in N-speciation between the respective parental fluids, which would largely be controlled by the oxidation state of the fibrous rim and cuboid growth environments (i.e., N2 vs. NH4 + or NH3). We also note that this C- and N-isotope variability could indicate temporal changes to the source(s) of the respective parental fluids, such that each stage of fibrous diamond growth reflects the emplacement of separate pulses of proto-kimberlitic fluid—from distinct carbon and nitrogen sources, and/or with varying N-species—into the lithospheric mantle.
Chiesi, Francesca; Ciancaleoni, Matteo; Galli, Silvia; Primi, Caterina
2012-01-01
This article is aimed at evaluating the possibility that Set I of the Advanced Progressive Matrices (APM-Set I) can be employed to assess fluid ability in a short time frame. The APM-Set I was administered to a sample of 1,389 primary and secondary school students. Confirmatory factor analysis attested to the unidimensionality of the scale. Item…
Rogers, Laura Q; Fogleman, Amanda; Verhulst, Steven; Bhugra, Mudita; Rao, Krishna; Malone, James; Robbs, Randall; Robbins, K Thomas
2015-01-01
Social cognitive theory (SCT) measures related to exercise adherence in head and neck cancer (HNCa) patients were developed. Enrolling 101 HNCa patients, psychometric properties and associations with exercise behavior were examined for barriers self-efficacy, perceived barriers interference, outcome expectations, enjoyment, and goal setting. Cronbach's alpha ranged from.84 to.95; only enjoyment demonstrated limited test-retest reliability. Subscales for barriers self-efficacy (motivational, physical health) and barriers interference (motivational, physical health, time, environment) were identified. Multiple SCT constructs were cross-sectional correlates and prospective predictors of exercise behavior. These measures can improve the application of the SCT to exercise adherence in HNCa patients.
DEFF Research Database (Denmark)
Liang, Xiaodong; Yan, Wei; Thomsen, Kaj;
2015-01-01
A critical test for the perturbed-chain statistical associating fluid theory (PC-SAFT) equation of state (FOS) is the modeling of systems containing petroleum fluid and polar compounds. In this work, two approaches are proposed for the simplified PC-SAFT EOS to obtain the necessary pure component...
Directory of Open Access Journals (Sweden)
Yang XJ
2015-08-01
Full Text Available Xiao-Jun Yang,1,* Yan-Bo Wang,2,3,* Zhi-Wei Zhou,4,* Guo-Wei Wang,2 Xiao-Hong Wang,1 Qing-Fu Liu,1 Shu-Feng Zhou,4 Zhen-Hai Wang2,3 1Department of Intensive Care Unit, 2Neurology Center, General Hospital of Ningxia Medical University, Yinchuan, Ningxia, People’s Republic of China; 3Key Laboratory of Brain Diseases of Ningxia, Yinchuan, Ningxia, People’s Republic of China; 4Department of Pharmaceutical Sciences, College of Pharmacy, University of South Florida, Tampa, FL, USA *These authors contributed equally to this work Abstract: Ventilator-associated pneumonia (VAP is a life-threatening disease that is associated with high rates of morbidity and likely mortality, placing a heavy burden on an individual and society. Currently available diagnostic and therapeutic approaches for VAP treatment are limited, and the prognosis of VAP is poor. The present study aimed to reveal and discriminate the identification of the full spectrum of the pathogens in patients with VAP using high-throughput sequencing approach and analyze the species richness and complexity via alpha and beta diversity analysis. The bronchoalveolar lavage fluid samples were collected from 27 patients with VAP in intensive care unit. The polymerase chain reaction products of the hypervariable regions of 16S rDNA gene in these 27 samples of VAP were sequenced using the 454 GS FLX system. A total of 103,856 pyrosequencing reads and 638 operational taxonomic units were obtained from these 27 samples. There were four dominant phyla, including Proteobacteria, Firmicutes, Actinobacteria, and Bacteroidetes. There were 90 different genera, of which 12 genera occurred in over ten different samples. The top five dominant genera were Streptococcus, Acinetobacter, Limnohabitans, Neisseria, and Corynebacterium, and the most widely distributed genera were Streptococcus, Limnohabitans, and Acinetobacter in these 27 samples. Of note, the mixed profile of causative pathogens was observed. Taken
Ren, Aixia; Zhang, Weiqiang; Yarlagadda, Sunitha; Sinha, Chandrima; Arora, Kavisha; Moon, Chang-Suk; Naren, Anjaparavanda P
2013-04-26
The PDZ (postsynaptic density-95/discs large/zona occludens-1) domain-based interactions play important roles in regulating the expression and function of the cystic fibrosis transmembrane conductance regulator (CFTR). Several PDZ domain-containing proteins (PDZ proteins for short) have been identified as directly or indirectly interacting with the C terminus of CFTR. To better understand the regulation of CFTR processing, we conducted a genetic screen and identified MAST205 (a microtubule-associated serine/threonine kinase with a molecular mass of 205 kDa) as a new CFTR regulator. We found that overexpression of MAST205 increased the expression of CFTR and augmented CFTR-mediated fluid transport in a dose-dependent manner. Conversely, knockdown of MAST205 inhibited CFTR function. The PDZ motif of CFTR is required for the regulatory role of MAST205 in CFTR expression and function. We further demonstrated that MAST205 and the CFTR-associated ligand competed for binding to CFTR, which facilitated the processing of CFTR and consequently up-regulated the expression and function of CFTR at the plasma membrane. More importantly, we found that MAST205 could facilitate the processing of F508del-CFTR mutant and augment its quantity and channel function at the plasma membrane. Taken together, our data suggest that MAST205 plays an important role in regulating CFTR expression and function. Our findings have important clinical implications for treating CFTR-associated diseases such as cystic fibrosis and secretory diarrheas.
Kuška, Martin; Trnka, Radek; Kuběna, Aleš A; Růžička, Jiří
2016-01-01
People construe reality by using words as basic units of meaningful categorization. The present theory-driven study applied the method of a free association task to explore how people express the concepts of the world and the self in words. The respondents were asked to recall any five words relating with the word world. Afterward they were asked to recall any five words relating with the word self. The method of free association provided the respondents with absolute freedom to choose any words they wanted. Such free recall task is suggested as being a relatively direct approach to the respondents' self- and world-related conceptual categories, without enormous rational processing. The results provide us, first, with associative ranges for constructs of the world and the self, where some associative dimensions are defined by semantic polarities in the meanings of peripheral categories (e.g., Nature vs. Culture). Second, our analysis showed that some groups of verbal categories that were associated with the words world and self are central, while others are peripheral with respect to the central position. Third, the analysis of category networks revealed that some categories play the role of a transmitter, mediating the pathway between other categories in the network.
Health by association? Social capital, social theory, and the political economy of public health.
Szreter, Simon; Woolcock, Michael
2004-08-01
Three perspectives on the efficacy of social capital have been explored in the public health literature. A "social support" perspective argues that informal networks are central to objective and subjective welfare; an "inequality" thesis posits that widening economic disparities have eroded citizens' sense of social justice and inclusion, which in turn has led to heightened anxiety and compromised rising life expectancies; a "political economy" approach sees the primary determinant of poor health outcomes as the socially and politically mediated exclusion from material resources. A more comprehensive but grounded theory of social capital is presented that develops a distinction between bonding, bridging, and linking social capital. It is argued that this framework helps to reconcile these three perspectives, incorporating a broader reading of history, politics, and the empirical evidence regarding the mechanisms connecting types of network structure and state-society relations to public health outcomes. PMID:15282219
Associative Symmetry, Antisymmetry, and a Theory of Pigeons' Equivalence-Class Formation
Urcuioli, Peter J.
2008-01-01
Five experiments assessed associative symmetry in pigeons. In Experiments 1A, 1B and 2, pigeons learned two-alternative symbolic matching with identical sample- and comparison-response requirements and with matching stimuli appearing in all possible locations. Despite controlling for the nature of the functional stimuli and insuring all requisite…
An Associative-Activation Theory of Children's and Adults' Memory Illusions
Howe, Mark L.; Wimmer, Marina C.; Gagnon, Nadine; Plumpton, Shannon
2009-01-01
The effects of associative strength and gist relations on rates of children's and adults' true and false memories were examined in three experiments. Children aged 5-11 and university-aged adults participated in a standard Deese/Roediger-McDermott false memory task using DRM and category lists in two experiments and in the third, children…
Associative theories of goal-directed behaviour: a case for animal-human translational models
S. de Wit; A. Dickinson
2009-01-01
Associative accounts of goal-directed action, developed in the fields of human ideomotor action and that of animal learning, can capture cognitive belief-desire psychology of human decision-making. Whereas outcome-response accounts can account for the fact that the thought of a goal can call to mind
Guenther, Gerhard K.
1995-01-01
The rheology and development morphology of textured fluids have been investigated. The first fluid considered in this work was a liquid crystalline polymer consisting of isotropic and anisotropic solutions of poly-p-phenyleneterephthalamide (PPT) in sulfuric acid. The second textured fluid considered in this work was an immiscible polymer blend consisting of poly(ethylene terephthalate) (PET) and nylon 6,6. The role played by liquid crystalline order (LCO) and a polydomain ...
West, Phillip B.
2006-01-17
A method and apparatus suitable for coupling seismic or other downhole sensors to a borehole wall in high temperature and pressure environments. In one embodiment, one or more metal bellows mounted to a sensor module are inflated to clamp the sensor module within the borehole and couple an associated seismic sensor to a borehole wall. Once the sensing operation is complete, the bellows are deflated and the sensor module is unclamped by deflation of the metal bellows. In a further embodiment, a magnetic drive pump in a pump module is used to supply fluid pressure for inflating the metal bellows using borehole fluid or fluid from a reservoir. The pump includes a magnetic drive motor configured with a rotor assembly to be exposed to borehole fluid pressure including a rotatable armature for driving an impeller and an associated coil under control of electronics isolated from borehole pressure.
Kundu, Pijush K; Dowling, David R
2011-01-01
Fluid mechanics, the study of how fluids behave and interact under various forces and in various applied situations-whether in the liquid or gaseous state or both-is introduced and comprehensively covered in this widely adopted text. Revised and updated by Dr. David Dowling, Fluid Mechanics, 5e is suitable for both a first or second course in fluid mechanics at the graduate or advanced undergraduate level. Along with more than 100 new figures, the text has been reorganized and consolidated to provide a better flow and more cohesion of topics.Changes made to the
Transport between two fluids across their mutual flow interface: the streakline approach
Balasuriya, Sanjeeva
2016-01-01
Mixing between two different miscible fluids with a mutual interface must be initiated by fluid transporting across this fluid interface, caused for example by applying an unsteady velocity agitation. In general, there is no necessity for this physical flow barrier between the fluids to be associated with extremal or exponential attraction as might be revealed by applying Lagrangian coherent structures, finite-time Lyapunov exponents or other methods on the fluid velocity. It is shown that streaklines are key to understanding the breaking of the interface under velocity agitations, and a theory for locating the relevant streaklines is presented. Simulations of streaklines in a cross-channel mixer and a perturbed Kirchhoff's elliptic vortex are quantitatively compared to the theoretical results. A methodology for quantifying the unsteady advective transport between the two fluids using streaklines is presented.
Basic developments in fluid dynamics
Holt, Maurice
2012-01-01
Basic Developments in Fluid Dynamics, Volume 2 focuses on the developments, approaches, methodologies, reactions, and processes involved in fluid dynamics, including sea motion, wave interactions, and motion of spheres in a viscous fluid.The selection first offers information on inviscid cavity and wake flows and weak-interaction theory of ocean waves. Discussions focus on steady and unsteady cavity flows, radiation balance, theory of weak interactions in random fields, interactions between gravity waves and the atmosphere, and interactions within the ocean. The text then examines low Reynolds
Molecular thermodynamics of nonideal fluids
Lee, Lloyd L
2013-01-01
Molecular Thermodynamics of Nonideal Fluids serves as an introductory presentation for engineers to the concepts and principles behind and the advances in molecular thermodynamics of nonideal fluids. The book covers related topics such as the laws of thermodynamics; entropy; its ensembles; the different properties of the ideal gas; and the structure of liquids. Also covered in the book are topics such as integral equation theories; theories for polar fluids; solution thermodynamics; and molecular dynamics. The text is recommended for engineers who would like to be familiarized with the concept
Institute of Scientific and Technical Information of China (English)
2007-01-01
The equation of the state of the hydrogen bonding fluid system of AaDd type is studied by the principle of statistical mechanics. The influences of hydrogen bonds on the equation of state of the system are obtained based on the change in volume due to hydrogen bonds. Moreover,the number density fluc-tuations of both molecules and hydrogen bonds as well as their spatial correlation property are inves-tigated. Furthermore,an equation describing relation between the number density correlation function of "molecules-hydrogen bonds" and that of molecules and hydrogen bonds is derived. As application,taking the van der Waals hydrogen bonding fluid as an example,we considered the effect of hydrogen bonds on its relevant statistical properties.
Caractérisation géochimique des fluides associés aux minéralisations Pb sbnd Zn de Bou-Dahar (Maroc)
Adil, Samira; Bouabdellah, Mohammed; Grandia, Fidel; Cardellach, Esteve; Canals, Àngel
2004-11-01
The Bou-Dahar Pb sbnd Zn Mississippi Valley deposits located in the eastern part of the High Atlas Range (Morocco) are hosted by a Liassic reefal complex. Fluid inclusion and 'crush-leach' data show that two distinct fluids were involved in the mineralisation deposition: a warmer, more saline fluid (180 °C, >25 wt% NaCl equivalent) and a cooler, less saline fluid (70 °C, 16 wt% equivalent NaCl). Mixing of these two fluids resulted in the precipitation of the ore. The solute composition of the ore-forming brine suggests that the MVT mineralising fluids were probably a mixture of halite-dissolution fluids and evaporated seawater. To cite this article: S. Adil et al., C. R. Geoscience 336 (2004).
Basniev, Kaplan S; Chilingar, George V 0
2012-01-01
The mechanics of fluid flow is a fundamental engineering discipline explaining both natural phenomena and human-induced processes, and a thorough understanding of it is central to the operations of the oil and gas industry. This book, written by some of the world's best-known and respected petroleum engineers, covers the concepts, theories, and applications of the mechanics of fluid flow for the veteran engineer working in the field and the student, alike. It is a must-have for any engineer working in the oil and gas industry.
Yokota, Jun-Ichi; Shimoda, Satoe
2015-05-01
Vertigo and dizziness are common clinical manifestations after traffic accident-associated whiplash injury. Recently, Shinonaga et al. (2001) suggested that more than 80% of patients with whiplash injury complaining of these symptoms showed cerebrospinal (CSF) hypovolemia on radioisotope (RI) cisternography (111In-DTPA). However, neuro-otological studies to investigate the pathophysiological mechanisms underlying these symptoms have been insufficient. In the present study, patients complaining of these symptoms with CSF hypovolemia after traffic accidents were investigated with posturography and electronystagmography (ENG). Fourteen patients (4 men, 10 women; 24-52 yr) were examined with posturography and showed parameters (tracking distance & area) significantly (pwomen; 31-52 yr) were further investigated with ENG. The slow phase peak velocities of optokinetic nystagmus (OKN) and optokinetic-after nystagmus (OKAN) were significantly (p<0.01) reduced (62.64±6.9 SD deg/sec, 60.76±10.74 SD deg/sec, respectively) and frequencies of OKN were reduced (139.7±10.75 SD), while the ocular smooth pursuit was relatively preserved. Magnetic resonance images (sagittal view) of these five patients demonstrated the downward displacement of the cerebellar tonsils and flattening of the pons, which are characteristic features of CSF hypovolemia, called "brain sagging." Our results suggest that brain sagging due to CSF hypovolemia impairs vestibular and vestibulocerebellar functions, which may cause dizziness and vertigo. PMID:25957209
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Paul J. Thibault
2015-07-01
Full Text Available I take Saussure’s distinction between associative and syntagmatic relations in la langue as the starting point for a re-examination of the relationship between memory and language. Saussure’s remarks on this relationship are sparse and fragmentary, cast in terms of the now largely abandoned classical accounts of early neurologists such as Broca and Wernicke, who saw language in the brain as a series of interconnected cortical areas that were presumed to be the repositories of the neurophysiological processes of language function. I draw on Andy Clark’s (1993 idea of ‘associative engines’ to consider how the associative coordination of linguistic items involves (1 the potential for evolution to exploit the gap between gross environmental input to the organism and the input to specific neural networks; and (2 the potential for the language learner qua active agent to create some of its own learning environment. I then look at the ways in which the principle of the associative coordination of diverse series stored in long-term memory makes possible and gives rise to the analysis and segmentation of linguistic syntagms. This development, in turn, makes possible the detecting of the common part of diverse syntagms such that they can be replaced with more schematic ones. The resulting linguistic schema embodies functional constraints on the input data that are available to the learner and thus serve as a pedagogical device, which I call TEACHER FUNCTION. Jason Brown’s (1988 theory of microgenesis together with Deacon’s (1989 account of the dually ‘centrifugal’ and ‘centripetal’ flows of information in the brain provide the basis of a more coherent and complete account of the neural structure of language: The utterance is microgenetically elaborated as it ‘centrifugally’ unfolds over a sequence of neuroanatomical levels (e.g., limbic, generalised neocortex, sensorimotor cortex. On this basis, I articulate some links between
Effective perfect fluids in cosmology
Energy Technology Data Exchange (ETDEWEB)
Ballesteros, Guillermo [Museo Storico della Fisica e Centro Studi e Ricerche Enrico Fermi, Piazza del Viminale 1, I-00184 Rome (Italy); Bellazzini, Brando, E-mail: guillermo.ballesteros@unige.ch, E-mail: brando.bellazzini@pd.infn.it [Dipartimento di Fisica, Università di Padova and INFN, Sezione di Padova, Via Marzolo 8, I-35131 Padova (Italy)
2013-04-01
We describe the cosmological dynamics of perfect fluids within the framework of effective field theories. The effective action is a derivative expansion whose terms are selected by the symmetry requirements on the relevant long-distance degrees of freedom, which are identified with comoving coordinates. The perfect fluid is defined by requiring invariance of the action under internal volume-preserving diffeomorphisms and general covariance. At lowest order in derivatives, the dynamics is encoded in a single function of the entropy density that characterizes the properties of the fluid, such as the equation of state and the speed of sound. This framework allows a neat simultaneous description of fluid and metric perturbations. Longitudinal fluid perturbations are closely related to the adiabatic modes, while the transverse modes mix with vector metric perturbations as a consequence of vorticity conservation. This formalism features a large flexibility which can be of practical use for higher order perturbation theory and cosmological parameter estimation.
Research of ultrasonic attenuation theory in drilling fluid%超声波在钻井液中传播衰减理论研究
Institute of Scientific and Technical Information of China (English)
刘飞; 付建红; 张智; 许亮斌
2012-01-01
超声波流量计是现阶段精度最高、通用性好、灵敏度最高的流量计,但由于超声波在钻井液中衰减很大,使其未能测出钻井液的环空返出流量.通过Urick模型研究了超声波流量计在测量钻井液流量中超声波的衰减规律,分析了传播距离、超声波频率、液体密度等因素对超声波衰减的影响.通过研究得出钻井液中固相颗粒的数量每增加1个数量级,超声波能量衰减也增加一个数量级,超声波能量衰减随钻井液中固相颗粒直径、钻井液密度、传播距离的增加而增大,超声波频率越大,超声波能量衰减越快.该研究结果为超声波在钻井液测量中的进一步应用提供了理论基础.%At present, the return of drilling mud is measured by target type meter, but the result is not very accurate because of environment. The ultrasonic flowmeter is the most accurate, normal and sensitive apparatus, but the return flow of drilling mud can not be measured by ultrasonic flowmeter because of the huge ultrasonic attenuation in drilling fluid. The ultrasonic attenuation law was researched with the Urick Model when the flow of drilling fluid was measured by ultrasonic flowmeter. The effects of the factors on ultrasonic attenuation were analyzed, such as ultrasonic propagation distance, frequency, and liquid density..It was concluded that the ultrasonic attenuation would increase by one order of magnitude with the increase of the quantity of solid-phase pellet in the drilling fluid by one order of magnitude, and the ultrasonic attenuation increased with the increase of the diameter of solid-phase particles in the drilling fluid, the drilling fluid density and the prorogation distance. The larger ultrasonic frequency is, the quicker ultrasonic attenuation is.
Directory of Open Access Journals (Sweden)
Can Zhou
Full Text Available BACKGROUND: Rectal washout can prevent local recurrence after anterior resection of rectal cancer. Few studies have focused particularly on the association between irrigation fluids volume or agents and the risk of local recurrence after anterior resection of rectal cancer. OBJECTIVE: To estimate the association between irrigation fluids types, volumes of rectal washout and risk of local recurrence after anterior resection for cancer. DATA SOURCES: Relevant studies were identified by a search of Medline, Embase, Wiley Online Library, China National Knowledge Infrastructure, Cochrane Oral Health Group Specialized Register, Wanfang databases and Google Website from their inception until October 18,2013. STUDY SELECTION: Studies reporting the association between rectal washout types and volumes and risk of local recurrence after anterior resection for cancer were included. INTERVENTIONS: Eligible studies used rectal washout. Control groups were defined as no washout. STUDY APPRAISAL AND SYNTHESIS METHODS: Random-effects model were used to obtain summary estimates of RR and 95% CI, with Stata version 11 and RevMan 5.2.5 softwares used. The quality of report was appraised in reference to the MINORS item. RESULTS: Of the 919 rectal cancer patients in 8 included studies, a total of 61(6.64% cases of local recurrence were reported, with a pooled RR 0.51 (95%CI = 0.28-0.92, P = 0.03. The RRs 0.37 and 0.39 in normal saline and washout volume (≥ 1500 ml normal saline subgroup, respectively, indicated that rectal washout with normal saline, or ≥ 1500 ml in volume could significantly reduce local recurrence (LR rate (95% CI = 0.17-0.79, P = 0.01; 95% CI = 0.18-0.87, P = 0.02 after anterior resection for cancer. LIMITATION: The included studies were non-randomized observational studies, with diversity of study designs. CONCLUSION: Rectal washout with normal saline alone can reduce the risk of local recurrence in patients with resectable rectal cancer, and
DEFF Research Database (Denmark)
Brorsen, Michael
These lecture notes are intended mainly for the 7th semester course "Fluid Dynamics" offered by the Study Committee on Civil Engineering, Aalborg University.......These lecture notes are intended mainly for the 7th semester course "Fluid Dynamics" offered by the Study Committee on Civil Engineering, Aalborg University....
Mizowaki, Takashi; Sasayama, Takashi; Tanaka, Kazuhiro; Mizukawa, Katsu; Takata, Kumi; Nakamizo, Satoshi; Tanaka, Hirotomo; Nagashima, Hiroaki; Nishihara, Masamitsu; Hirose, Takanori; Itoh, Tomoo; Kohmura, Eiji
2015-09-01
Signal transducers and activators of transcription 3 (STAT3) are activated by various cytokines and oncogenes; however, the activity and pathogenesis of STAT3 in diffuse large B cell lymphoma of the central nervous system have not been thoroughly elucidated. We investigated the phosphorylation levels of STAT3 in 40 specimens of primary central nervous system diffuse large B-cell lymphoma (PCNS DLBCL) and analyzed the association between phsopho-STAT3 (pSTAT3) expression and cerebrospinal fluid (CSF) concentration of interleukin-10 (IL-10) or IL-6. Immunohistochemistry and Western blot analysis revealed that most of the specimens in PCNS DLBCL expressed pSTST3 protein, and a strong phosphorylation levels of STAT3 was statistically associated with high CSF IL-10 levels, but not with CSF IL-6 levels. Next, we demonstrated that recombinant IL-10 and CSF containing IL-10 induced the phosphorylation of STAT3 in PCNS DLBCL cells. Furthermore, molecular subtype classified by Hans' algorithm was correlated with pSTAT3 expression levels and CSF IL-10 levels. These results suggest that the STAT3 activity is correlated with CSF IL-10 level, which is a useful marker for STAT3 activity in PCNS DLBCLs.
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Pereira J.C.R.
2004-01-01
Full Text Available The present study compares the performance of stochastic and fuzzy models for the analysis of the relationship between clinical signs and diagnosis. Data obtained for 153 children concerning diagnosis (pneumonia, other non-pneumonia diseases, absence of disease and seven clinical signs were divided into two samples, one for analysis and other for validation. The former was used to derive relations by multi-discriminant analysis (MDA and by fuzzy max-min compositions (fuzzy, and the latter was used to assess the predictions drawn from each type of relation. MDA and fuzzy were closely similar in terms of prediction, with correct allocation of 75.7 to 78.3% of patients in the validation sample, and displaying only a single instance of disagreement: a patient with low level of toxemia was mistaken as not diseased by MDA and correctly taken as somehow ill by fuzzy. Concerning relations, each method provided different information, each revealing different aspects of the relations between clinical signs and diagnoses. Both methods agreed on pointing X-ray, dyspnea, and auscultation as better related with pneumonia, but only fuzzy was able to detect relations of heart rate, body temperature, toxemia and respiratory rate with pneumonia. Moreover, only fuzzy was able to detect a relationship between heart rate and absence of disease, which allowed the detection of six malnourished children whose diagnoses as healthy are, indeed, disputable. The conclusion is that even though fuzzy sets theory might not improve prediction, it certainly does enhance clinical knowledge since it detects relationships not visible to stochastic models.
Effective gravitational couplings for cosmological perturbations in generalized Proca theories
De Felice, Antonio; Heisenberg, Lavinia; Kase, Ryotaro; Mukohyama, Shinji; Tsujikawa, Shinji; Zhang, Ying-Li
2016-01-01
We consider the finite interactions of the generalized Proca theory including the sixth-order Lagrangian and derive the full linear perturbation equations of motion on the flat Friedmann-Lema\\^{i}tre-Robertson-Walker background in the presence of a matter perfect fluid. By construction, the propagating degrees of freedom (besides the matter perfect fluid) are two transverse vector perturbations, one longitudinal scalar, and two tensor polarizations. The Lagrangians associated with intrinsic v...
Ellenbogen, Jeffrey M; Hulbert, Justin C; Stickgold, Robert; Dinges, David F; Thompson-Schill, Sharon L
2006-07-11
Mounting behavioral evidence in humans supports the claim that sleep leads to improvements in recently acquired, nondeclarative memories. Examples include motor-sequence learning; visual-discrimination learning; and perceptual learning of a synthetic language. In contrast, there are limited human data supporting a benefit of sleep for declarative (hippocampus-mediated) memory in humans (for review, see). This is particularly surprising given that animal models (e.g.,) and neuroimaging studies (e.g.,) predict that sleep facilitates hippocampus-based memory consolidation. We hypothesized that we could unmask the benefits of sleep by challenging the declarative memory system with competing information (interference). This is the first study to demonstrate that sleep protects declarative memories from subsequent associative interference, and it has important implications for understanding the neurobiology of memory consolidation.
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Schellenberg Gerard D
2010-10-01
Full Text Available Abstract Background Alzheimer's disease (AD is common and highly heritable with many genes and gene variants associated with AD in one or more studies, including APOE ε2/ε3/ε4. However, the genetic backgrounds for normal cognition, mild cognitive impairment (MCI and AD in terms of changes in cerebrospinal fluid (CSF levels of Aβ1-42, T-tau, and P-tau181P, have not been clearly delineated. We carried out a genome-wide association study (GWAS in order to better define the genetic backgrounds to these three states in relation to CSF levels. Methods Subjects were participants in the Alzheimer's Disease Neuroimaging Initiative (ADNI. The GWAS dataset consisted of 818 participants (mainly Caucasian genotyped using the Illumina Human Genome 610 Quad BeadChips. This sample included 410 subjects (119 Normal, 115 MCI and 176 AD with measurements of CSF Aβ1-42, T-tau, and P-tau181P Levels. We used PLINK to find genetic associations with the three CSF biomarker levels. Association of each of the 498,205 SNPs was tested using additive, dominant, and general association models while considering APOE genotype and age. Finally, an effort was made to better identify relevant biochemical pathways for associated genes using the ALIGATOR software. Results We found that there were some associations with APOE genotype although CSF levels were about the same for each subject group; CSF Aβ1-42 levels decreased with APOE gene dose for each subject group. T-tau levels tended to be higher among AD cases than among normal subjects. From adjusted result using APOE genotype and age as covariates, no SNP was associated with CSF levels among AD subjects. CYP19A1 'aromatase' (rs2899472, NCAM2, and multiple SNPs located on chromosome 10 near the ARL5B gene demonstrated the strongest associations with Aβ1-42 in normal subjects. Two genes found to be near the top SNPs, CYP19A1 (rs2899472, p = 1.90 × 10-7 and NCAM2 (rs1022442, p = 2.75 × 10-7 have been reported as genetic
ZENO: A Critical Fluid Light Scattering Experiment
1994-01-01
The ZENO experiment flew on the STS-62, it is designed to verify intriguing, but previously untested, theories in fluid physics. These theories attempt to describe dramatic changes in the properties of fluids near the critical temperature at which the vapor and liquid forms co-exist.
Miyata, Tatsuhiko; Miyazaki, Sanae
2016-08-01
The accuracy of the temperature derivative of radial distribution function obtained under hypernetted chain (HNC), Kovalenko-Hirata (KH), Percus-Yevick (PY) and Verlet-modified (VM) closure approximations is examined for one-component Lennard-Jones fluid. As relevant thermodynamic quantities, constant-volume heat capacity and thermal pressure coefficient are investigated in terms of their accuracy under the above four approximations. It is found that HNC and KH closures overestimate these quantities, whereas PY closure tends to underestimate them. VM closure predicts rather accurately the quantities. A significant cancellation is observed along the integration for the above quantities under HNC and KH closures, especially at high density state.
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Melzer Nico
2012-07-01
Full Text Available Abstract Objective The purpose of this paper is to report a patient with otherwise unexplained cerebellar ataxia with serum antibodies against contactin-associated protein-2 (CASPR-2 and provide a detailed description of the composition of cellular infiltrates in the cerebrospinal fluid (CSF compared to the peripheral blood (PB. CASPR-2 antibodies strongly labeling axons of cerebellar granule neurons have recently been identified in sera from nine patients with otherwise unexplained progressive cerebellar ataxia with mild to severe cerebellar atrophy. Design This is a report of a single case. Methods The study methods used were neurologic examination, magnetic resonance imaging, fluorodeoxyglucose positron emisson tomography, lumbar puncture and multicolor flow-cytometry. Results A 23-year-old Caucasian male presented with a two-year history of a progressive cerebellar and brainstem syndrome. Magnetic resonance imaging (MRI showed pronounced cerebellar atrophy, especially of the medial parts of the hemispheres and the vermis. Cerebral fluorodeoxyglucose positron emission tomography (FDG-PET showed pronounced hypometabolism of the whole cerebellum. CASPR-2 antibodies were detected in the serum but not the CSF, and none of the staging and laboratory assessments revealed other causes of progressive cerebellar degeneration. Interestingly, flow-cytometry of the CSF as compared to the PB showed increased fractions of CD138+ plasma cells as well as human leukocyte antigen (HLA-DR+ CD8+ T cells suggesting that both B cells and CD8+ T cells were preferentially recruited to and activated within the CSF- (and putatively central nervous system (CNS- compartment. Conclusion We confirm the association of CASPR-2 serum antibodies with cerebellar ataxia and provide the first evidence for a combined humoral and cellular immune response in this novel antibody-associated inflammatory CNS disease.
Maltby, John; Day, Liz; Hatcher, Ruth M; Tazzyman, Sarah; Flowe, Heather D; Palmer, Emma J; Frosch, Caren A; O'Reilly, Michelle; Jones, Ceri; Buckley, Chloe; Knieps, Melanie; Cutts, Katie
2016-08-01
Three studies were conducted to investigate people's conceptions of online trolls, particularly conceptions associated with psychological resilience to trolling. In Study 1, a factor analysis of participants' ratings of characteristics of online trolls found a replicable bifactor model of conceptions of online trolls, with a general factor of general conceptions towards online trolls being identified, but five group factors (attention-conflict seeking, low self-confidence, viciousness, uneducated, amusement) as most salient. In Study 2, participants evaluated hypothetical profiles of online trolling messages to establish the validity of the five factors. Three constructs (attention-conflict seeking, viciousness, and uneducated) were actively employed when people considered profiles of online trolling scenarios. Study 3 introduced a 20-item 'Conceptions of Online Trolls scale' to examine the extent to which the five group factors were associated with resilience to trolling. Results indicated that viewing online trolls as seeking conflict or attention was associated with a decrease in individuals' negative affect around previous trolling incidents. Overall, the findings suggest that adopting an implicit theories approach can further our understanding and measurement of conceptions towards trolling through the identification of five salient factors, of which at least one factor may act as a resilience strategy. PMID:26403842
A density functional theory for vapor-liquid interfaces using the PCP-SAFT equation of state
Gross, J.
2009-01-01
A Helmholtz energy functional for inhomogeneous fluid phases based on the perturbed-chain polar statistical associating fluid theory (PCP-SAFT) equation of state is proposed. The model is supplemented with a capillary wave contribution to the surface tension to account for long-wavelength fluctuatio
O'Shea, Gabrielle; Spence, Susan H; Donovan, Caroline L
2014-01-01
The aim of this study was to investigate whether depressed adolescents differed from non-depressed adolescents in terms of constructs consistent with those that are proposed to underpin interpersonal psychotherapy. In particular, it was hypothesized that compared with non-depressed adolescents, depressed adolescents would demonstrate a greater number of negative life events associated with interpersonal loss and major life transitions, a more insecure attachment style and poorer communication skills, interpersonal relationships and social support. Thirty-one clinically diagnosed depressed adolescents were matched with 31 non-depressed adolescents on age, gender and socio-economic status. The 62 participants were aged between 12 and 19 years and comprised 18 male and 44 female adolescents. On a self-report questionnaire, depressed adolescents reported a greater number of negative interpersonal life events, a less secure attachment style and scored higher on all insecure attachment styles compared with the non-depressed adolescents. In addition, depressed adolescents demonstrated lower levels of social skill (on both adolescent and parent report), a poorer quality of relationship with parents (on both adolescent and parent report) and lower social competence (adolescent report only). Parents of depressed adolescents also reported more negative parental attitudes and behaviours towards their adolescent compared with parents of non-depressed adolescents. Thus, the results of this study are consistent with the constructs underlying interpersonal psychotherapy and suggest their usefulness in the assessment, conceptualization and treatment of adolescent depression. Clinical implications are discussed. PMID:23801523
Soto, Enrique
2013-01-01
This fluid dynamics video is an entry for the Gallery of Fluid Motion for the 66th Annual Meeting of the Fluid Dynamics Division of the American Physical Society. We show the curious behaviour of a light ball interacting with a liquid jet. For certain conditions, a ball can be suspended into a slightly inclined liquid jet. We studied this phenomenon using a high speed camera. The visualizations show that the object can be `juggled' for a variety of flow conditions. A simple calculation showed that the ball remains at a stable position due to a Bernoulli-like effect. The phenomenon is very stable and easy to reproduce.
Rom, Eldad; Mikulincer, Mario
2003-06-01
Four studies examined attachment-style differences in group-related cognitions and behaviors. In Studies 1-2, participants completed scales on group-related cognitions and emotions. In Studies 3-4, participants were divided into small groups, and their performance in group tasks as well as the cohesion of their group were assessed. Both attachment anxiety and avoidance in close relationships were associated with negative group-related cognitions and emotions. Anxiety was also related to the pursuit of closeness goals and impaired instrumental performance in group tasks. Avoidance was related to the pursuit of distance goals and deficits in socioemotional and instrumental performance. Group cohesion significantly moderated the effects of attachment anxiety. The discussion emphasizes the relevance of attachment theory within group contexts.
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Qingqin S Li
Full Text Available Proteolytic fragments of amyloid and post-translational modification of tau species in Cerebrospinal fluid (CSF as well as cerebral amyloid deposition are important biomarkers for Alzheimer's Disease. We conducted genome-wide association study to identify genetic factors influencing CSF biomarker level, cerebral amyloid deposition, and disease progression. The genome-wide association study was performed via a meta-analysis of two non-overlapping discovery sample sets to identify genetic variants other than APOE ε4 predictive of the CSF biomarker level (Aβ1-42, t-Tau, p-Tau181P, t-Tau:Aβ1-42 ratio, and p-Tau181P:Aβ1-42 ratio in patients enrolled in the Alzheimer's Disease Neuroimaging Initiative (ADNI study. Loci passing a genome-wide significance threshold of P < 5 x 10-8 were followed-up for replication in an independent sample set. We also performed joint meta-analysis of both discovery sample sets together with the replication sample set. In the discovery phase, we identified variants in FRA10AC1 associated with CSF Aβ1-42 level passing the genome-wide significance threshold (directly genotyped SNV rs10509663 PFE = 1.1 x 10-9, imputed SNV rs116953792 PFE = 3.5 x 10-10, rs116953792 (Pone-sided = 0.04 achieved replication. This association became stronger in the joint meta-analysis (directly genotyped SNV rs10509663 PFE = 1.7 x 10-9, imputed SNV rs116953792 PFE = 7.6 x 10-11. Additionally, we identified locus 15q21 (imputed SNV rs1503351 PFE = 4.0 x 10-8 associated with CSF Aβ1-42 level. No other variants passed the genome-wide significance threshold for other CSF biomarkers in either the discovery sample sets or joint analysis. Gene set enrichment analyses suggested that targeted genes mediated by miR-33, miR-146, and miR-193 were enriched in various GWAS analyses. This finding is particularly important because CSF biomarkers confer disease susceptibility and may be predictive of the likelihood of disease progression in Alzheimer
Bernard, Peter S
2015-01-01
This book presents a focused, readable account of the principal physical and mathematical ideas at the heart of fluid dynamics. Graduate students in engineering, applied math, and physics who are taking their first graduate course in fluids will find this book invaluable in providing the background in physics and mathematics necessary to pursue advanced study. The book includes a detailed derivation of the Navier-Stokes and energy equations, followed by many examples of their use in studying the dynamics of fluid flows. Modern tensor analysis is used to simplify the mathematical derivations, thus allowing a clearer view of the physics. Peter Bernard also covers the motivation behind many fundamental concepts such as Bernoulli's equation and the stream function. Many exercises are designed with a view toward using MATLAB or its equivalent to simplify and extend the analysis of fluid motion including developing flow simulations based on techniques described in the book.
International Nuclear Information System (INIS)
This paper describes RI cisternographic (RIC) examinations of whiplash-associated disorder (WAD) and results of their treatment with nerve block and epidural blood patch (EBP) conducted in authors' facilities. Subjects were 40 chronic (av. symptomatic period of 3.1 y) WAD patients (av. age 34 y) with traffic (28 cases), sports (7) and falling (5) causes with complication of suspicious cerebrospinal fluid (CSF) leak. RIC was done 2.5-24 hr after injection of 37 MBq of 111In-diethylenetriamine pentaacetic acid (DTPA) in the medullary space through epidural puncturing needle. Positive finding of clear leak or early accumulation of RI in the bladder was seen in 21 cases and negative, in 19. Positive patients had significantly higher rates of headache, abnormal vision and fatigue than negative ones. EBP was conducted through X-ray to all positive patients and to negative ones with strongly suspicious leak complication (7 cases), which resulted in improvement of symptoms like headache and vision in the former, but no improvement in the latter cases. Repeated RIC of the patients with poor improvement in the former was suggested effective for judgment of repetition of EBP treatment. Cervical facet joint blocks were found effective in cases with posterior cervical pain. Symptoms in WAD accompanying headache should be differentially diagnosed whether it is derived from posttraumatic CSF leak or from pain due to cervical facet arthritis. (R.T.)
Zhang, Z.; Shen, K.; Liou, J.; Xu, Z.
2005-12-01
Abundant primary fluid inclusions are recognized in omphacite of ultrahigh-pressure (UHP) eclogites from the main hole of the Chinese Continental Scientific Drilling (CCSD), located at the southern Sulu orogenic belt. The eclogites consist of garnet, omphacite, coesite and rutile. Mineral and fluid inclusions are distributed alternatively and parallel to each other. The solid inclusions occur as needles with a length of 10~100 m and a width of 1~10 m whereas the fluid inclusions occur as tubes with the size varying from less then 3~5 m to greater then 50 m. The mineral inclusions were identified as quartz. Most fluid inclusions contain a gas bubble, a liquid phase and one to several solids. The liquid and gas phases are determined as H2O. The solid phases include halite, quartz and calcite, as well as opaque and unknown minerals. Some small thin-tubed fluid inclusions contain little or no solid and even without gas bubble; they contain dominantly water. The inclusion fluid was estimated to contain components in the system of NaCl-CaCl2-CO2-H2O-SiO2 with possibly trace Fe and Mg. We suggest that these fluid inclusions were conventional primary ones, and trapped during omphacite crystallization; upon decompression they acted as nucleation site for the crystallographically controlled precipitation of quartz from the omphacite matrix. Therefore the omphacite is considered to be one of the major fluid carriers during subduction of continental crust to mantle depths.
Santos, Maria Fernanda L; Silva, Janete; Fachel, Jandyra M G; Pulgati, Fernando H
2010-08-01
This paper assesses the effects of non-aqueous fluids (NAF)-associated drill cuttings discharge on shelf break macrobenthic communities in the Campos Basin, off the southeast Brazilian coast, Rio de Janeiro State. Samples were taken with a 0.25-m2 box corer from surrounding two oil and gas wells on three monitoring cruises: before drilling, three months after drilling, and 22 months after drilling. Statistical methodologies used Bayesian geostatistical and analysis of variance models to evaluate the effects of the NAF-associated drill cuttings discharge and to define the impact area. The results indicated that marked variations were not observed in the number of families between cruises, though there were changes in the fauna composition. The changes seen in biological descriptors in both control and background situation areas were not considered significant, showing a temporal homogeneity in means. The impact area presented changes in biological descriptors of communities and trophic structure during the three cruises and such changes were correlated to chemical and physical variables related to the drilling activities, as a result of the mix of drill cuttings and sediment and the anoxic conditions established in the substrate. In that area, three months after drilling, a decrease in diversity and an increase in density, motile deposit-feeders and Pol/Crp ratio, and dominance of opportunistic organisms, such as the capitellid Capitella sp., were observed and, 22 months after drilling, an increase of diversity, reduction of dominance of capitellid polychaete, changes in the fauna composition, and a dominance of opportunistic burrowing and tube-building organisms were observed, indicating an ecological succession process. PMID:20524059
Savickienė, Jūratė; Baronaitė, Sandra; Zentelytė, Aistė; Treigytė, Gražina
2016-01-01
Human amniotic-fluid-derived mesenchymal stem cells (AF-MSCs) are interesting for their multilineage differentiation potential and wide range of therapeutic applications due to the ease of culture expansion. However, MSCs undergo replicative senescence. So far, the molecular mechanisms that underlie fetal diseases and cell senescence are still poorly understood. Here, we analyzed senescence-associated morphologic, molecular, and epigenetic characteristics during propagation of MSCs derived from AF of normal and fetus-affected pregnancy. AF-MSCs cultures from both cell sources displayed quite similar morphology and expression of specific cell surface (CD44, CD90, and CD105) and stemness (Oct4, Nanog, Sox2, and Rex1) markers but had interindividual variability in proliferation capability and time to reach senescence. Within passages 4 and 8, senescent cultures exhibited typical morphological features, senescence-associated β-galactosidase activity, increased levels of p16, and decreased levels of miR-17 and miR-21 but showed differential expression of p21, p53, and ATM dependently on the onset of cell senescence. These differences correlated with changes in the level of chromatin modifiers (DNMT1 and HDAC1) and polycomb group proteins (EZH2, SUZ12, and BMI1) paralleling with changes in the expression of repressive histone marks (H3K9me3 and H3K27me3) and stemness markers (Oct4, Nanog, Sox2, and Rex1). Therefore epigenetic factors are important for AF-MSCs senescence process that may be related with individuality of donor or a fetus malignancy status. PMID:27803714
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Jūratė Savickienė
2016-01-01
Full Text Available Human amniotic-fluid-derived mesenchymal stem cells (AF-MSCs are interesting for their multilineage differentiation potential and wide range of therapeutic applications due to the ease of culture expansion. However, MSCs undergo replicative senescence. So far, the molecular mechanisms that underlie fetal diseases and cell senescence are still poorly understood. Here, we analyzed senescence-associated morphologic, molecular, and epigenetic characteristics during propagation of MSCs derived from AF of normal and fetus-affected pregnancy. AF-MSCs cultures from both cell sources displayed quite similar morphology and expression of specific cell surface (CD44, CD90, and CD105 and stemness (Oct4, Nanog, Sox2, and Rex1 markers but had interindividual variability in proliferation capability and time to reach senescence. Within passages 4 and 8, senescent cultures exhibited typical morphological features, senescence-associated β-galactosidase activity, increased levels of p16, and decreased levels of miR-17 and miR-21 but showed differential expression of p21, p53, and ATM dependently on the onset of cell senescence. These differences correlated with changes in the level of chromatin modifiers (DNMT1 and HDAC1 and polycomb group proteins (EZH2, SUZ12, and BMI1 paralleling with changes in the expression of repressive histone marks (H3K9me3 and H3K27me3 and stemness markers (Oct4, Nanog, Sox2, and Rex1. Therefore epigenetic factors are important for AF-MSCs senescence process that may be related with individuality of donor or a fetus malignancy status.
Brun-Battistini, D; Sandoval-Villalbazo, A
2016-01-01
Richard C. Tolman analyzed the relation between a temperature gradient and a gravitational field in an equilibrium situation. In 2012, Tolman\\textquoteright s law was generalized to a non-equilibrium situation for a simple dilute relativistic fluid. The result in that scenario, obtained by introducing the gravitational force through the molecular acceleration, couples the heat flux with the metric coefficients and the gradients of the state variables. In the present paper it is shown, by \\textquotedblleft suppressing\\textquotedblright{} the molecular acceleration in Boltzmann\\textquoteright s equation, that a gravitational field drives a heat flux. This procedure corresponds to the description of particle motion through geodesics, in which a Newtonian limit to the Schwarzschild metric is assumed. The effect vanishes in the non-relativistic regime, as evidenced by the direct evaluation of the corresponding limit.
Energy Technology Data Exchange (ETDEWEB)
Svaasand, Eldrid
2008-04-15
The work presented in this thesis concerns the study of complex nano fluids. The interaction of particles in dispersions under the influence of electric and magnetic fields has been studied. The main focus has been the investigation of the behavior of carbon particle dispersions. A novel type of carbon material, namely carbon cone (CC) material, has been characterized using atomic force microscope, scanning tunneling microscope and scanning electron microscope. The CC material is a mixed powder consisting of carbon particles with the shape of disks and cones and a small amount of amorphous carbon particles. The length or diameter of the particles vary between 0.5-5 mum with thickness varying between 10-50 nm. The results confirm the cone angles as predicted by theory. The various microscopy images show that the surfaces of the particles seem corrugated. It should be noted that it is the mixed particle powder which it is referred to when it is written 'carbon cone particles' or 'CC particles'. The dispersion of CC particles in silicon oil was studied under the influence of an electric field. The particles were found to align in an ac electric field and structure formation was observed at very low electric fields. The growth rate was found to vary exponentially with the electric field. The structure formations were permanent (under zero shear rate), not dissolving when the electric field was turned off. This was attributed to the strong Van der Waals forces associated with carbon particles. Electrorheological measurements were carried out for dispersions with varying CC particle concentrations. All samples showed a Bingham fluid behavior with a finite yield stress. The yield stress was found to depend only weakly on the electric field. The results showed that the ER efficiency as measured by the relative increase in viscosity compared to the zero field viscosity, increases with decreasing concentration with a maximum factor of approx10 for the
Directory of Open Access Journals (Sweden)
Yamashita Masaomi
2011-06-01
Full Text Available Abstract Background One of the sources of knee pain in osteoarthritis (OA is believed to be related to local chronic inflammation of the knee joints, which involves the production of inflammatory cytokines such as tumor necrosis factor alpha (TNFα, interleukin (IL-6, and nerve growth factor (NGF in the synovial membrane, and these cytokines are believed to promote pathological OA. In the present study, correlations between proinflammatory cytokines in knee synovial fluid and radiographic changes and functional scores and pain scores among OA patients were examined. Methods Synovial fluid was harvested from the knees of 47 consecutive OA patients, and the levels of TNFα, IL-6, and NGF were measured using enzyme-linked immunosorbent assays. Osteoarthritic knees were classified using Kellgren-Lawrence (KL grading (1-4. The Western Ontario and McMaster University Osteoarthritis Index (WOMAC was used to assess self-reported physical function, pain, and stiffness. Results TNFα and IL-6 were detectable in knee synovial, whereas NGF was not. TNFα was not correlated with the KL grade, whereas IL-6 had a significantly negative correlation. We observed differences in the correlations between TNFα and IL-6 with WOMAC scores and their subscales (pain, stiffness, and physical function. TNFα exhibited a significant correlation with the total score and its 3 subscales, whereas IL-6 exhibited a moderately significant negative correlation only with the subscale of stiffness. Conclusions The present study demonstrated that the concentrations of proinflammatory cytokines are correlated with KL grades and WOMAC scores in patients with knee OA. Although TNFα did not have a significant correlation with the radiographic grading, it was significantly associated with the WOMAC score. IL-6 had a significant negative correlation with the KL grading, whereas it had only a weakly significant correlation with the subscore of stiffness. The results suggest that these
Fingering instability in the flow of a power-law fluid on a rotating disc
Arora, Akash; Doshi, Pankaj
2016-01-01
A computational study of the flow of a non-Newtonian power law fluid on a spinning disc is considered here. The main goal of this work is to examine the effect of non-Newtonian nature of the fluid on the flow development and associated contact line instability. The governing mass and momentum balance equations are simplified using the lubrication theory. The resulting model equation is a fourth order non-linear PDE which describes the spatial and temporal evolutions of film thickness. The movement of the contact line is modeled using a constant angle slip model. To solve this moving boundary problem, a numerical method is developed using a Galerkin/finite element method based approach. The numerical results show that the spreading rate of the fluid strongly depends on power law exponent n. It increases with the increase in the shear thinning character of the fluid (n 1). It is also observed that the capillary ridge becomes sharper with the value of n. In order to examine the stability of these ridges, a linear stability theory is also developed for these power law fluids. The dispersion relationship depicting the growth rate for a given wave number has been reported and compared for different power-law fluids. It is found that the growth rate of the instability decreases as the fluid becomes more shear thinning in nature, whereas it increases for more shear thickening fluids.
Van Pelt, A.
1992-01-01
I. INTRODUCTION AND THEORY This PhD research is mainly concerned with the global phase behaviour, that is calculated from the Simplified-Perturbed-Hard-Chain equation. This equation distinguishes itself from many other equations of state by a sound theoretical background. We enter the field of the t
Directory of Open Access Journals (Sweden)
Gesa Feenders
Full Text Available Vocal learning is a critical behavioral substrate for spoken human language. It is a rare trait found in three distantly related groups of birds-songbirds, hummingbirds, and parrots. These avian groups have remarkably similar systems of cerebral vocal nuclei for the control of learned vocalizations that are not found in their more closely related vocal non-learning relatives. These findings led to the hypothesis that brain pathways for vocal learning in different groups evolved independently from a common ancestor but under pre-existing constraints. Here, we suggest one constraint, a pre-existing system for movement control. Using behavioral molecular mapping, we discovered that in songbirds, parrots, and hummingbirds, all cerebral vocal learning nuclei are adjacent to discrete brain areas active during limb and body movements. Similar to the relationships between vocal nuclei activation and singing, activation in the adjacent areas correlated with the amount of movement performed and was independent of auditory and visual input. These same movement-associated brain areas were also present in female songbirds that do not learn vocalizations and have atrophied cerebral vocal nuclei, and in ring doves that are vocal non-learners and do not have cerebral vocal nuclei. A compilation of previous neural tracing experiments in songbirds suggests that the movement-associated areas are connected in a network that is in parallel with the adjacent vocal learning system. This study is the first global mapping that we are aware for movement-associated areas of the avian cerebrum and it indicates that brain systems that control vocal learning in distantly related birds are directly adjacent to brain systems involved in movement control. Based upon these findings, we propose a motor theory for the origin of vocal learning, this being that the brain areas specialized for vocal learning in vocal learners evolved as a specialization of a pre-existing motor
Feenders, Gesa; Liedvogel, Miriam; Rivas, Miriam; Zapka, Manuela; Horita, Haruhito; Hara, Erina; Wada, Kazuhiro; Mouritsen, Henrik; Jarvis, Erich D
2008-03-12
Vocal learning is a critical behavioral substrate for spoken human language. It is a rare trait found in three distantly related groups of birds-songbirds, hummingbirds, and parrots. These avian groups have remarkably similar systems of cerebral vocal nuclei for the control of learned vocalizations that are not found in their more closely related vocal non-learning relatives. These findings led to the hypothesis that brain pathways for vocal learning in different groups evolved independently from a common ancestor but under pre-existing constraints. Here, we suggest one constraint, a pre-existing system for movement control. Using behavioral molecular mapping, we discovered that in songbirds, parrots, and hummingbirds, all cerebral vocal learning nuclei are adjacent to discrete brain areas active during limb and body movements. Similar to the relationships between vocal nuclei activation and singing, activation in the adjacent areas correlated with the amount of movement performed and was independent of auditory and visual input. These same movement-associated brain areas were also present in female songbirds that do not learn vocalizations and have atrophied cerebral vocal nuclei, and in ring doves that are vocal non-learners and do not have cerebral vocal nuclei. A compilation of previous neural tracing experiments in songbirds suggests that the movement-associated areas are connected in a network that is in parallel with the adjacent vocal learning system. This study is the first global mapping that we are aware for movement-associated areas of the avian cerebrum and it indicates that brain systems that control vocal learning in distantly related birds are directly adjacent to brain systems involved in movement control. Based upon these findings, we propose a motor theory for the origin of vocal learning, this being that the brain areas specialized for vocal learning in vocal learners evolved as a specialization of a pre-existing motor pathway that controls
Dhandapani, Sivashanmugam; Srinivasan, Anirudh
2016-01-01
Triple spinal dysraphism is extremely rare. There are published reports of multiple discrete neural tube defects with intervening normal segments that are explained by the multisite closure theory of primary neurulation, having an association with Chiari malformation Type II consistent with the unified theory of McLone. The authors report on a 1-year-old child with contiguous myelomeningocele and lipomyelomeningocele centered on Type I split cord malformation with Chiari malformation Type II and hydrocephalus. This composite anomaly is probably due to select abnormalities of the neurenteric canal during gastrulation, with a contiguous cascading impact on both dysjunction of the neural tube and closure of the neuropore, resulting in a small posterior fossa, probably bringing the unified theory of McLone closer to the unified theory of Pang.
Cosmology with moving bimetric fluids
García-García, Carlos; Maroto, Antonio L.; Martín-Moruno, Prado
2016-01-01
We study cosmological implications of bigravity and massive gravity solutions with non-simultaneously diagonal metrics by considering the generalized Gordon and Kerr-Schild ansatzes. The scenario that we obtain is equivalent to that of General Relativity with additional non-comoving perfect fluids. We show that the most general ghost-free bimetric theory generates three kinds of effective fluids whose equations of state are fixed by a function of the ansatz. Different choices of such function...
Institute of Scientific and Technical Information of China (English)
梁世强; 张秉坚; 路映红; 胡文暄; 金之钧
2001-01-01
A model for the freely jointed square well chain fluid is developed based on the thermodynamic perturbation theory of Barker Henderson,Zhang and Wertheim.The analytic representations of square well monomer by Zhang are extended to obtain a series of representations for thermodynamic properties of square well chain fluids using the incorporating structural information for square well monomer of Wertheim's TPT1 model.The same work has been done using incorporating structural information for the diatomic square well fluid of TPT D model.The calculated results of compressibility factor,residual internal energy and constant volume heat capacity of 4 mer,8 mer and 16 mer chain fluids are tested against the MC results and a careful comparison between the model from TPT1 and that from TPT D has been made.The former agree with MC results much better than the later,especially for internal energy.To obtain the constant volume heat capacity,NVT MC simulations have been performed.%在 Barker Henderson, Zhang以及 Wertheim 等微扰理论的基础上 ,以方阱势硬球流体为参考体系 ,将 Zhang的解析表达方法与 Wertheim 的链成键自由能的处理方法结合起来 ,推导出自由链接的链状分子流体的 Helmholtz自由能的解析表达式 ,并得到了压缩因子、内能、恒容热容等热力学性质的计算式 .计算结果与 MC(Monte Carlo)模拟结果吻合良好 .对 Zhang的解析表达式与“ TPT D” (二阶 Wertheim微扰理论 )的结合也作了推导和计算 .
Energy Technology Data Exchange (ETDEWEB)
Payne, J.; Andrews, C. [Fisheries and Oceans Canada, St. John' s, NL (Canada); Guiney, J. [Oceans Ltd., St. John' s, NL (Canada); Whiteway, S. [Jacques Whitford Ltd., St. John' s, NL (Canada)
2006-07-01
This study assessed dose-response relationships for alkane levels in sand sediments spiked with drilling muds that contain an aliphatic hydrocarbon-based synthetic fluid (IPAR). In addition to examining the toxicity levels in 3 sediment bioassays, the impact of drilling wastes on benthic communities in the vicinity of pipelines was also evaluated. The studies were conducted over a 3-year period in order to assess the drilling fluid's potential for producing sediment toxicity. The study also assessed the potential of IPAR to generate anaerobic conditions in sediments over a 12-month period. Pilot studies were conducted to assess false positive levels for bentonite and barite. Results of the tests indicated that sediment toxicity from the use of IPAR drilling fluids was confined to a range of tens of meters from cutting piles located in the immediate vicinity of the drilling rig sites. Results also suggested that the use of Microtox assays should be carefully monitored due to its potential for producing false positives. Distinct anaerobic conditions did not occur after a year of weathering until IPAR concentrations reached the 1000 ppm range. It was concluded that high concentrations of barite additions were not toxic to capelin, snowcrab larvae, or planktonic jellyfish after a period of 24 hours. No mortalities were observed for flounders force-fed high concentrations of barite at weekly intervals. 4 refs.
DEFF Research Database (Denmark)
Kallestrup, M; Møller, Holger Jon; Tankisi, H;
2015-01-01
using an enzyme-linked immunosorbent assay. RESULTS: Soluble CD163 levels were significantly higher in the cerebrospinal fluid and serum of the participants with Type 2 diabetes compared with the control participants [cerebrospinal fluid: median (range) 107 (70-190) vs 84 (54-115) μg/l, P ....01 and serum: 2305 (920-7060) vs 1420 (780-2740) μg/l, P higher levels of soluble CD163 in the cerebrospinal fluid...... nerve function. Higher levels of soluble CD163 in people with diabetic polyneuropathy suggest that inflammation plays a role in the development of neural impairment. The relationship between cerebrospinal fluid soluble CD163 level and peripheral nerve conduction indicates that soluble CD163 may...
Benes, Jan; Haidingerova, Lenka; Pouska, Jiri; Stepanik, Jan; Stenglova, Alena; Zatloukal, Jan; Pradl, Richard; Chytra, Ivan; Kasal, Eduard
2015-01-01
Background The use of goal directed fluid protocols in intermediate risk patients undergoing hip or knee replacement was studied in few trials using invasive monitoring. For this reason we have implemented two different fluid management protocols, both based on a novel totally non-invasive arterial pressure monitoring device and compared them to the standard (no-protocol) treatment applied before the transition in our academic institution. Methods Three treatment groups were compared in this ...
Gauge theory of collective modes
International Nuclear Information System (INIS)
The classical theory of Riemann ellipsoids is formulated naturally as a gauge theory based on a principal G-bundle P. The structure group G = SO(3) is the vorticity group and the bundle P = GL+ (3, ℝ) is the connected component of the general linear group. The base manifold is the space of positive-definite real 3 × 3 symmetric matrices, identified geometrically with the space of inertia ellipsoids. Non-holonomic constraints determine connections on the bundle. In particular, the trivial connection corresponds to rigid body motion, the natural Riemannian connection to irrotational flow and the invariant connection to the falling cat. The curvature form determines the fluid's field tensor which is an analogue of the familiar Faraday tensor. Associated G-bundles and the covariant derivative yield new quantum geometrical collective models that are a natural generalization of the Bohr model. These new geometric structures formulate the collective model as a Yang-Mills gauge theory.
Pedlosky, Joseph
1982-01-01
The content of this book is based, largely, on the core curriculum in geophys ical fluid dynamics which land my colleagues in the Department of Geophysical Sciences at The University of Chicago have taught for the past decade. Our purpose in developing a core curriculum was to provide to advanced undergraduates and entering graduate students a coherent and systematic introduction to the theory of geophysical fluid dynamics. The curriculum and the outline of this book were devised to form a sequence of courses of roughly one and a half academic years (five academic quarters) in length. The goal of the sequence is to help the student rapidly advance to the point where independent study and research are practical expectations. It quickly became apparent that several topics (e. g. , some aspects of potential theory) usually thought of as forming the foundations of a fluid-dynamics curriculum were merely classical rather than essential and could be, however sadly, dispensed with for our purposes. At the same tim...
Pedlosky, Joseph
1979-01-01
The content of this book is based, largely, on the core curriculum in geophys ical fluid dynamics which I and my colleagues in the Department of Geophysical Sciences at The University of Chicago have taught for the past decade. Our purpose in developing a core curriculum was to provide to advanced undergraduates and entering graduate students a coherent and systematic introduction to the theory of geophysical fluid dynamics. The curriculum and the outline of this book were devised to form a sequence of courses of roughly one and a half academic years (five academic quarters) in length. The goal of the sequence is to help the student rapidly advance to the point where independent study and research are practical expectations. It quickly became apparent that several topics (e. g. , some aspects of potential theory) usually thought of as forming the foundations of a fluid-dynamics curriculum were merely classical rather than essential and could be, however sadly, dispensed with for our purposes. At the same ti...
Xu, Huiyun; Zhang, Jian; Wu, Jiawei; Guan, Ying; Weng, Yuanyuan; Shang, Peng
2012-01-01
Interstitial fluid flow stress is one of the most important mechanical stimulations of bone cells under physiological conditions. Osteocytes and osteoblasts act as primary mechanosensors within bones, and in vitro are able to respond to fluid shear stress, both morphologically and functionally. However, there is little information about the response of integrin-associated molecules using both osteoblasts and osteocytes. In this study, we investigated the changes in response to 2 hours of oscillatory fluid flow stress in the MLO-Y4 osteocyte-like cell line and the MC3T3-E1 osteoblast-like cell line. MLO-Y4 cells exhibited a significant increase in the expression of integrin-associated molecules, including OPN, CD44, vinculin and integrin αvβ3. However, there was no or limited increase observed in MC3T3-E1 osteoblast-like cells. Cell area and fiber stress formation were also markedly promoted by fluid flow only in MLO-Y4 cells. But the numbers of processes per cell remain unaffected in both cell lines. PMID:23096360
Mur-Novales, R; López-Gatius, F; Serrano-Pérez, B; García-Ispierto, I; Darwich, L; Cabezón, O; de Sousa, N M; Beckers, J F; Almería, S
2016-04-01
Plasma concentrations of PAG-1 are used for pregnancy diagnosis and as a marker of placental/foetal well-being, while those of PAG-2 may be an indicator of abortion risk in Neospora caninum-infected cows. Studies have shown that N. caninum infection modifies PAG-1 and PAG-2 patterns in maternal blood plasma. However, no prior work has examined the effects of N. caninum infection on concentrations of PAGs in foetal fluids. In this study, PAG-1, PAG-2 and pH levels were determined in the amniotic and allantoic fluids of foetuses collected at 152 days of gestation from control uninfected dams and from dams experimentally infected with N. caninum on Day 110 of gestation. Foetal fluids from infected foetuses had significantly higher PAG-2 concentrations (p = 0.026) and pH values (p = 0.02) than fluids from non-infected foetuses. In infected foetuses, significantly higher concentrations of PAG-1 (p fluid samples showing antibodies against N. caninum than those without antibodies. Moreover, pH values were significantly higher (p = 0.011) in foetal fluid samples with antibodies than in samples from non-infected foetuses. In conclusion, this is the first report on the effect of N. caninum infection on PAG levels in foetal fluids. Our results indicate that following the experimental infection of dams with N. caninum on Day 110 of gestation, foetal fluids collected from the infected foetuses of these dams featured higher PAG-1 and PAG-2 levels and pH values than fluids from non-infected controls, provided that the samples tested showed the presence of antibodies. The clinical implications of these findings are that following infection with N. caninum, most cows will experience some level of placental damage and that this injury correlates with foetal fluid PAG levels and pH. PMID:26936628
Gunaydin, Murat; Malek, Emanuel
2016-01-01
We propose a non-associative phase space algebra for M-theory backgrounds with locally non-geometric fluxes based on the non-associative algebra of octonions. Our proposal is based on the observation that the non-associative algebra of the non-geometric R-flux background in string theory can be obtained by a proper contraction of the simple Malcev algebra generated by imaginary octonions. Furthermore, by studying a toy model of a four-dimensional locally non-geometric M-theory background which is dual to a twisted torus, we show that the non-geometric background is "missing" a momentum mode. The resulting seven-dimensional phase space can thus be naturally identified with the imaginary octonions. This allows us to interpret the full uncontracted algebra of imaginary octonions as the uplift of the string theory R-flux algebra to M-theory, with the contraction parameter playing the role of the string coupling constant $g_s$.
Heart failure - fluids and diuretics
... Remember, some foods, such as soups, puddings, gelatin, ice cream, popsicles and others contain fluids. When you eat ... and Metabolism; American Heart Association Interdisciplinary Council on Quality of Care and Outcomes Research. State of the ...
Kinetics of Surfactant Adsorption at Fluid-Fluid Interfaces
Diamant, H.; Andelman, D.
1996-01-01
We present a theory for the kinetics of surfactant adsorption at the interface between an aqueous solution and another fluid (air, oil) phase. The model relies on a free-energy formulation. It describes both the diffusive transport of surfactant molecules from the bulk solution to the interface, and the kinetics taking place at the interface itself. When applied to non-ionic surfactant systems, the theory recovers results of previous models, justify their assumptions and predicts a diffusion-...
Fuhr, Thomas
2012-01-01
Sammelrezension von: 1. Edward W. Taylor / Patricia Cranton, and Associates (Hrsg.): The Handbook of Transformative Learning, Theory, Research, and Practice, San Francisco, CA: Jossey-Bass 2012 (598 S.; ISBN 978-1-111-21891-4) 2. Jack Mezirow / Edward W. Taylor, and Associates (Hrsg.): Transformative Learning in Practice, Insights from Community, Workplace, and Higher Education, San Francisco, CA: Jossey-Bass 2009 (303 S.; ISBN 978-0-470-25790-6)
Caserta, A; Salusti, E
2016-01-01
In this paper we propose the application of a new model of transients of pore pressure p and solute density \\r{ho} in geologic porous media. This model is rooted in the non-linear waves theory, the focus of which is advection and effect of large pressure jumps on strain (due to large p in a non-linear version of the Hooke law). It strictly relates p and \\r{ho} evolving under the effect of a strong external stress. As a result, the presence of quick and sharp transients in low permeability rocks is unveiled, i.e. the non-linear Burgers solitons. We therefore propose that the actual transport process in porous rocks for large signals is not the linear diffusion, but could be governed by solitons. A test of an eventual presence of solitons in a rock is here proposed, and then applied to Pierre Shale, Bearpaw Shale, Boom Clay and Oznam-Mugu silt and clay. A quick analysis showing the presence of solitons for nuclear waste disposal and salty water intrusions is also analyzed. Finally, in a kind of "theoretical exp...
On Radiative Fluids in Anisotropic Spacetimes
Shogin, Dmitry
2016-01-01
We apply the second-order Israel-Stewart theory of relativistic fluid- and thermodynamics to a physically realistic model of a radiative fluid in a simple anisotropic cosmological background. We investigate the asymptotic future of the resulting cosmological model and review the role of the dissipative phenomena in the early Universe. We demonstrate that the transport properties of the fluid alone, if described appropriately, do not explain the presently observed accelerated expansion of the Universe. Also, we show that, in constrast to the mathematical fluid models widely used before, the radiative fluid does approach local thermal equilibrium at late times, although very slowly, due to the cosmological expansion.
Directory of Open Access Journals (Sweden)
Mika Yamaga
Full Text Available OBJECTIVE: To explore the molecular function of Osteopontin (OPN in the pathogenesis of human OA, we compared the expression levels of OPN in synovial fluid with clinical parameters such as arthroscopic observation of cartilage damage and joint pain after joint injury. METHODS: Synovial fluid was obtained from patients who underwent anterior cruciate ligament (ACL reconstruction surgery from 2009 through 2011 in our university hospital. The amounts of intact OPN (OPN Full and it's N-terminal fragment (OPN N-half in synovial fluid from each patient were quantified by ELISA and compared with clinical parameters such as severity of articular cartilage damage (TMDU cartilage score and severity of joint pain (Visual Analogue Scale and Lysholm score. RESULTS: Within a month after ACL rupture, both OPN Full and N-half levels in patient synovial fluid were positively correlated with the severity of joint pain. In contrast, patients with ACL injuries greater than one month ago felt less pain if they had higher amounts of OPN N-half in synovial fluid. OPN Full levels were positively correlated with articular cartilage damage in lateral tibial plateau. CONCLUSION: Our data suggest that OPN Full and N-half have distinct functions in articular cartilage homeostasis and in human joint pain.
Galilean relativistic fluid mechanics
Ván, Péter
2015-01-01
Single component Galilean-relativistic (nonrelativistic) fluids are treated independently of reference frames. The basic fields are given, their balances, thermodynamic relations and the entropy production is calculated. The usual relative basic fields, the mass, momentum and energy densities, the diffusion current density, the pressure tensor and the heat flux are the time- and spacelike components of the third order mass-momentum-energy density tensor according to a velocity field. The transformation rules of the basic fields are derived and prove that the non-equilibrium thermodynamic background theory, that is the Gibbs relation, extensivity condition and the entropy production is absolute, that is independent of the reference frame and also of the fluid velocity. --- Az egykomponensu Galilei-relativisztikus (azaz nemrelativisztikus) disszipativ folyadekokat vonatkoztatasi rendszertol fuggetlenul targyaljuk. Megadjuk az alapmennyisegeket, ezek merlegeit, a termodinamikai osszefuggeseket es kiszamoljuk az ...
Institute of Scientific and Technical Information of China (English)
无
2002-01-01
Quantitative representation of complicated behavior of fluid mixtures in the critical region by any of equation-of-state theories re-mains as a difficult thermodynamic topics to date. In the present work, a computational efforts were made for representing various types ofcritical loci of binary water with hydrocarbon systems showing Type Ⅱ and Type Ⅲ phase behavior by an elementary equation of state [calledmulti-fluid nonrandom lattice fluid EOS (MF-NLF EOS)] based on the lattice statistical mechanical theory. The model EOS requires two mo-lecular parameters which representing molecular size and interaction energy for a pure component end single adjustable interaction energyparameter for binary mixtures. Critical temperature and pressure data were used to obtain molecular size parameter and vapor pressure datawere used to obtain interaction energy parameter. The MF-NLF EOS model adapted in the present study correlated quantitatively well the criti-cal loci of various binary water with hydrocarbon systems.
Institute of Scientific and Technical Information of China (English)
王雪玲
2011-01-01
Both the Leader - Member Exchange theory and the differential mode of association theory are about the research on social circle. While the social circles in the two theories are related but different. It will play an important role in every aspects of team research and organization research to recognize the difference and connection between the two different circles. This paper, based on the literature, focus on comparing the difference among them, and provide a basis for future research.%领导-成员交换理论和差序格局都是对“圈子”的研究，都是对稀缺资源进行配置的模式或格局，两者既有联系又存在区别。这两种理论对研究中国企业组织具有重要作用。
Reentrant Wetting of Network Fluids
Bernardino, N. R.; Telo da Gama, M. M.
2012-09-01
We use a simple mesoscopic Landau-Safran theory of network fluids to show that a reentrant phase diagram, in the “empty liquid” regime, leads to nonmonotonic surface tension and reentrant wetting, as previously reported for binary mixtures. One of the wetting transitions is of the usual kind, but the low temperature transition may allow the display of the full range of fluctuation regimes predicted by renormalization group theory.
Pnueli, David; Gutfinger, Chaim
1997-01-01
This text is intended for the study of fluid mechanics at an intermediate level. The presentation starts with basic concepts, in order to form a sound conceptual structure that can support engineering applications and encourage further learning. The presentation is exact, incorporating both the mathematics involved and the physics needed to understand the various phenomena in fluid mechanics. Where a didactical choice must be made between the two, the physics prevails. Throughout the book the authors have tried to reach a balance between exact presentation, intuitive grasp of new ideas, and creative applications of concepts. This approach is reflected in the examples presented in the text and in the exercises given at the end of each chapter. Subjects treated are hydrostatics, viscous flow, similitude and order of magnitude, creeping flow, potential flow, boundary layer flow, turbulent flow, compressible flow, and non-Newtonian flows. This book is ideal for advanced undergraduate students in mechanical, chemical, aerospace, and civil engineering. Solutions manual available.
Institute of Scientific and Technical Information of China (English)
李伟力; 袁世鹏; 霍菲阳; 张奕黄
2011-01-01
Theory of fluid heat transfer and 3-D finite volume method were used to calculate the temperature field of megawatt scale permanent magnet synchronous generator for wind turbine with natural ventilation cooling. Firstly, the calculation methods for heat source and the equivalent heat transfer coefficient were given; a 3-D fluid mathematic model was established. Secondly, the model of the test prototype machine for fluid and temperature coupling analysis was established. Compared with the experimental data, the correctness of the calculation model was verified. The 3-D temperature field of a 1.5 MW half-direct permanent magnet synchronous generator for wind turbine was calculated by the same method. Based on the operational features of large power permanent magnet synchronous generator for wind turbine, the 3-D distribution of temperature field was computed when the generator running in the rated wind speed with the rated load. And the graph of temperature change when generator running with rated load in different environment temperature was drawn. At last, the distributions of temperature which generator running in different wind speeds were calculated.%采用流体传热理论和有限体积法计算自然风冷式兆瓦级永磁同步风力发电机的三维温度场.确定热源及等效导热系数的计算方法,建立三维流体的数学模型；对一台实验样机建立三维流动与传热耦合计算的模型,并通过与实验结果的对比,验证计算方法的合理性.利用相同方法对一台1.5 MW永磁同步风力发电机的三维温度场进行计算与分析,在此基础上,根据大功率永磁风力发电机的实际运行特点,计算该发电机额定风速下额定负载运行时的三维温度场分布,并绘制了不同环境温度时电机额定状态下各部分的温度变化图.仿真计算在不同风速下发电机的温度分布.
Instrumentation, measurements, and experiments in fluids
Rathakrishnan, E
2007-01-01
NEED AND OBJECTIVE OF EXPERIMENTAL STUDY Some Fluid Mechanics MeasurementsMeasurement SystemsSome of the Important Quantities Associated with FluidFlow MeasurementsFUNDAMENTALS OF FLUID MECHANICSProperties of FluidsThermodynamic PropertiesSurface TensionAnalysis of Fluid FlowBasic and Subsidiary Laws for Continuous MediaKinematics of Fluid FlowStreamlinesPotential FlowViscous FlowsGas DynamicsWIND TUNNELSLow-Speed Wind TunnelsPower Losses in a Wind TunnelHigh-Speed Wind TunnelsHypersonic TunnelsInstrume
Transport Coefficients of Fluids
Eu, Byung Chan
2006-01-01
Until recently the formal statistical mechanical approach offered no practicable method for computing the transport coefficients of liquids, and so most practitioners had to resort to empirical fitting formulas. This has now changed, as demonstrated in this innovative monograph. The author presents and applies new methods based on statistical mechanics for calculating the transport coefficients of simple and complex liquids over wide ranges of density and temperature. These molecular theories enable the transport coefficients to be calculated in terms of equilibrium thermodynamic properties, and the results are shown to account satisfactorily for experimental observations, including even the non-Newtonian behavior of fluids far from equilibrium.
Directory of Open Access Journals (Sweden)
Kopáček Jaroslav
2016-01-01
Full Text Available This paper focuses on the importance of detection reliability, especially in complex fluid systems for demanding production technology. The initial criterion for assessing the reliability is the failure of object (element, which is seen as a random variable and their data (values can be processed using by the mathematical methods of theory probability and statistics. They are defined the basic indicators of reliability and their applications in calculations of serial, parallel and backed-up systems. For illustration, there are calculation examples of indicators of reliability for various elements of the system and for the selected pneumatic circuit.
Batterham, Philip J.; Christensen, Helen; Mackinnon, Andrew J.
2009-01-01
The long-term relationship between lower intelligence and mortality risk in later life is well established, even when controlling for a range of health and sociodemographic measures. However, there is some evidence for differential effects in various domains of cognitive performance. Specifically, tests of fluid intelligence may have a stronger…
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Hamiltonian formalism for general-relativistic adiabatic fluids
International Nuclear Information System (INIS)
We derive the Hamiltonian structures of three theories: non-relativistic, special-relativistic, and general-relativistic adiabatic fluids, each in the Eulerian representation in Riemannian space (or Lorentzian spacetime), all by the same procedure using standard variational principles. The evolution in each case is generated by a Hamiltonian that is equivalent to that obtained from a canonical analysis. For the gravitational variables, the Poisson bracket has the usual canonical symplectic structure. However, for the fluid variables, the three theories all share the same Lie-Poisson bracket, when expressed in the appropriate spaces of physical variables constructed here. This shared Lie-Poisson bracket is associated to the dual of the semidirect-product Lie algebra of vector fields acting on differential forms. An immediate consequence of this shared structure is that each of these theories possesses an infinite family of conservation laws: the so-called ''Casimirs'' that belong to the kernel of the Lie-Poisson bracket. The role of these Casimirs in the study of Lyapunov stability (or dynamic stability) for fluid equilibria is discussed. The relationship of this approach to other approaches in the literature is also discussed. (orig.)
Institute of Scientific and Technical Information of China (English)
Liu Chang; Du Zhaohui; Zhou Qing; Hu Bo; Li Zhifeng; Yu Li; Xu Tao
2014-01-01
Background The presence of intracellular organisms (ICOs) in polymorphonuclear leukocytes obtained from bronchoalveolar lavage fluid (BALF) is a possible method for rapid diagnosis of ventilator-associated pneumonia (VAP).However,the validity of this diagnostic method remains controversial and the diagnostic thresholds reported by investigators were different.Our objective was to evaluate the accuracy of quantification of ICOs in BALF for the diagnosis of VAP,and to detect the best cutoff percentage of PMNs containing ICOs (PIC) in the microscopic examination of BALF for the diagnosis of VAP.Methods This was a prospective multi-center study conducted in 4 ICUs in Wuhan,China,which involved 181 patients suspected of first episode of VAP.BALF was obtained from all enrolled patients.The BALF samples underwent quantitative culture,cytological and bacteriological analysis to detect the culture results,PIC values and the morphological features of microorganisms.Definite diagnosis of VAP was based on pre-set criteria.The receiver-operating characteristic curve was used to detect the best cutoff point for PIG to diagnose VAP,and the diagnostic accuracy was calculated.Moreover,quantitative culture and Gram's stain of BALF were adopted to diagnose VAP,and their diagnostic accuracy was evaluated as well.Results There were 102 patients definitely diagnosed with VAP (VAP group),and 60 patients definitely diagnosed without VAP (no VAP group).We found that ICOs were present in 96.08％ (98 out of 102) of VAP patients and 20.00％ (12 out of 60) of no VAP patients.The PICs were significantly higher ((9.53±6.65)％ vs.(0.52±1.33)％,P＜0.01) in VAP group.In our study,the best cutoff point for PIC to diagnose VAP was 1.5％,which had a sensitivity of 94.12％,a specificity of 88.33％,a positive predictive value (PPV) of 93.20％ and a negative predictive value (NPV) of 89.83％.The area under the receiveroperating characteristic curve was 0.956 (95％ confidence interval,0
Geochemical modeling of fluid-fluid and fluid-mineral interactions during geological CO2 storage
Zhu, C.; Ji, X.; Lu, P.
2013-12-01
The long time required for effective CO2 storage makes geochemical modeling an indispensable tool for CCUS. One area of geochemical modeling research that is in urgent need is impurities in CO2 streams. Permitting impurities, such as H2S, in CO2 streams can lead to potential capital and energy savings. However, predicting the consequences of co-injection of CO2 and impurities into geological formations requires the understanding of the phase equilibrium and fluid-fluid interactions. To meet this need, we developed a statistical associating fluid theory (SAFT)-based equation of state (EOS) for the H2S-CO2-H2O-NaCl system at 373.15
Orbital Fluid Resupply Assessment
Eberhardt, Ralph N.
1989-01-01
Orbital fluid resupply can significantly increase the cost-effectiveness and operational flexibility of spacecraft, satellites, and orbiting platforms and observatories. Reusable tankers are currently being designed for transporting fluids to space. A number of options exist for transporting the fluids and propellant to the space-based user systems. The fluids can be transported to space either in the Shuttle cargo bay or using expendable launch vehicles (ELVs). Resupply can thus be accomplished either from the Shuttle bay, or the tanker can be removed from the Shuttle bay or launched on an ELV and attached to a carrier such as the Orbital Maneuvering Vehicle (OMV) or Orbital Transfer Vehicle (OTV) for transport to the user to be serviced. A third option involves locating the tanker at the space station or an unmanned platform as a quasi-permanent servicing facility or depot which returns to the ground for recycling once its tanks are depleted. Current modular tanker designs for monopropellants, bipropellants, and water for space station propulsion are discussed. Superfluid helium tankers are addressed, including trade-offs in tanker sizes, shapes to fit the range of ELVs currently available, and boil-off losses associated with longer-term (greater than 6-month) space-basing. It is concluded that the mixed fleet approach to on-orbit consumables resupply offers significant advantages to the overall logistics requirements.
Introduction to the physics of fluids and solids
Trefil, J S
2013-01-01
Introduction to the Physics of Fluids and Solids presents a way to learn continuum mechanics without mastering any other systems. It discusses an introduction to the principles of fluid mechanics. Another focus of study is the fluids in astrophysics. Some of the topics covered in the book are the rotation of the galaxy, the concept of stability, the fluids in motion, and the waves in fluids, the theory of the tides, the vibrations of the earth, and nuclear fission. The viscosity in fluids is covered. The flow of viscous fluids is discussed. The text identifies the general circulation of the a
Directory of Open Access Journals (Sweden)
Lesley eCheng
2013-08-01
Full Text Available Diagnostic tools for neurodegenerative diseases such as Alzheimer's disease (AD currently involve subjective neuropsychological testing and specialised brain imaging techniques. While definitive diagnosis requires a pathological brain evaluation at autopsy, neurodegenerative changes are believed to begin years before the clinical presentation of cognitive decline. Therefore, there is an essential need for reliable biomarkers to aid in the early detection of disease in order to implement preventative strategies. microRNAs (miRNA are small non-coding RNA species that are involved in post-transcriptional gene regulation. Expression levels of miRNA’s have potential as diagnostic biomarkers as they are known to circulate and tissue specific profiles can be identified in a number of bodily fluids such as plasma, CSF and urine. Recent developments in deep sequencing technology present a viable approach to develop biomarker discovery pipelines in order to profile microRNA signatures in bodily fluids specific to neurodegenerative diseases. Here we review the potential use of microRNA deep sequencing in biomarker identification from biological fluids and its translation into clinical practice.
Energy Technology Data Exchange (ETDEWEB)
Elders, W.A.
1986-07-01
Among the technical problems faced by the burgeoning geothermal industry is the disposal of spent fluids from power plants. Except in unusual circumstances the normal practice, especially in the USA, is to pump these spent fluids into injection wells to prevent contamination of surface waters, and possibly in some cases, to reduce pressure drawdown in the producing aquifers. This report is a survey of experience in geothermal injection, emphasizing geochemical problems, and a discussion of approaches to their possible mitigation. The extraction of enthalpy from geothermal fluid in power plants may cause solutions to be strongly supersaturated in various dissolved components such as silica, carbonates, sulfates, and sulfides. Injection of such supersaturated solutions into disposal wells has the potential to cause scaling in the well bores and plugging of the aquifers, leading to loss of injectivity. Various aspects of the geochemistry of geothermal brines and their potential for mineral formation are discussed, drawing upon a literature survey. Experience of brine treatment and handling, and the economics of mineral extraction are also addressed in this report. Finally suggestions are made on future needs for possible experimental, field and theoretical studies to avoid or control mineral scaling.
Five decades of tackling models for stiff fluid dynamics problems a scientific autobiography
Zeytounian, Radyadour Kh
2014-01-01
Rationality - as opposed to 'ad-hoc' - and asymptotics - to emphasize the fact that perturbative methods are at the core of the theory - are the two main concepts associated with the Rational Asymptotic Modeling (RAM) approach in fluid dynamics when the goal is to specifically provide useful models accessible to numerical simulation via high-speed computing. This approach has contributed to a fresh understanding of Newtonian fluid flow problems and has opened up new avenues for tackling real fluid flow phenomena, which are known to lead to very difficult mathematical and numerical problems irrespective of turbulence. With the present scientific autobiography the author guides the reader through his somewhat non-traditional career; first discovering fluid mechanics, and then devoting more than fifty years to intense work in the field. Using both personal and general historical contexts, this account will be of benefit to anyone interested in the early and contemporary developments of an important branch of the...
Geometry of Streamlines in Fluid Flow Theory
Directory of Open Access Journals (Sweden)
P. Samba Shiva Rao
1978-10-01
Full Text Available Intrinsic properties of lines of flow has been studied by employing anholonomic co ordinate system consisting of s-lines which are streamlines, n-lines the involutes of s-lines and b- lines the locus of centre of spherical curvature of s-lines. This gives rise to only two geometric parameters and interesting have been obtained. It was also shown that velocity can be expressed in terms of geometric parameters. Constancy of velocity along binormal line implies existence of Lump surface for the motion. It is found is not irrotational unless it is plane motion. In generalised screw motion it is found that wn/v=constant along the stream line.
Ohta, Yuji
1999-01-01
Instanton correction of prepotential of one-dimensional SL(2) Ruijsenaars model is presented with the help of Picard-Fuchs equation of Pakuliak-Perelomov type. It is shown that the instanton induced prepotential reduces to that of the SU(2) gauge theory coupled with a massive adjoint hypermultiplet.
Jester, Melanie; Johnson, Carla J.
2016-01-01
Children with specific language impairment (SLI) have difficulty engaging in social pretend play, which cannot be explained exclusively by their deficient language skills. Alternatively, the ability to represent mental states (Theory of Mind [ToM]) might be important in appreciating peers' perspectives during pretend play. This study investigated…
Fundamental trends in fluid-structure interaction
Galdi, Giovanni P
2010-01-01
The interaction of a fluid with a solid body is a widespread phenomenon in nature, occurring at different scales and different applied disciplines. Interestingly enough, even though the mathematical theory of the motion of bodies in a liquid is one of the oldest and most classical problems in fluid mechanics, mathematicians have, only very recently, become interested in a systematic study of the basic problems related to fluid-structure interaction, from both analytical and numerical viewpoints. ""Fundamental Trends in Fluid-Structure Interaction"" is a unique collection of important papers wr
Activities report in fluid mechanics
1986-10-01
The research conducted at the Lille Institute of Fluid Mechanics (IMFL) concerns four areas: flight mechanics, structural mechanics, aerodynamics and applied fluid mechanics. Within these four areas, these topics are discussed: characterization of the unsteady pressures on an airfoil in turbulence; adaptation of the Kalman-Rauch filtering-smoothing method to instrumented free spin tests; vulnerability of aircraft fuel tanks; water surface impact; influence of an oscillating spoiler on the surrounding aerodynamic field; gunfiring similarity theory and rules; flow around a cylinder at low Reynolds number by holographic velocimetry and laser Doppler velocimetry; compressible turbulent flow computation; and the wake of wind turbine towers are discussed.