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DiffusionDiffusion Magnetic Resonance ImagingDiffusion Tensor ImagingFacilitated DiffusionAnisotropyModels, BiologicalNerve Fibers, MyelinatedDiffusion of InnovationFluorescence Recovery After PhotobleachingBiological TransportKineticsDisk Diffusion Antimicrobial TestsBrainImage Processing, Computer-AssistedDiffusion Chambers, CultureImage Interpretation, Computer-AssistedComputer SimulationWaterMathematicsImage EnhancementAlgorithmsCorpus CallosumCell Membrane PermeabilityPermeabilityModels, TheoreticalMagnetic Resonance ImagingCell MembraneMetabolic Flux AnalysisBiophysicsMagnetic Resonance SpectroscopyBiological Transport, ActiveTime FactorsReproducibility of ResultsPhotobleachingModels, ChemicalSodiumMicrobial Sensitivity TestsBiophysical PhenomenaViscosityFluorescent DyesSkin AbsorptionInternal CapsulePotassiumCalciumSensitivity and SpecificityHydrogen-Ion ConcentrationMembranes, ArtificialChloridesSpectrometry, FluorescenceMembrane FluidityTemperatureDextransAnti-Bacterial AgentsOxygenGlucoseCitric Acid CycleThermal DiffusionPulmonary Diffusing CapacitySolutionsCarbonPyramidal TractsHeliumLipid BilayersCarbon IsotopesMonte Carlo MethodImmunodiffusionBrain MappingGlycolysisExtracellular SpaceMetabolic Networks and PathwaysBody WaterNeural PathwaysAgarImaging, Three-DimensionalMicroscopy, FluorescenceCarbon DioxideMembrane PotentialsPentose Phosphate PathwayRabbitsFluoresceinGelsFluoresceinsProtonsIonsEscherichia coliConvectionArtifactsModels, StatisticalMotionIon TransportMembrane LipidsAdenosine TriphosphateOxygen ConsumptionMicroscopy, ConfocalErythrocytesMembrane ProteinsLightOsmolar ConcentrationThermodynamicsFluorescence
EquationAdvection-Diffusion EquationsEquationsRelativisticCoefficientsDiapycnalRadiationElectron diffusionTransmembraneSpeciesProportionalConcentrationGradientsTurbulentRadialBoundary layerSteady stateAlgorithmBuoyancySchemeExperimentalParticlesProcessesEstimatesMassFiniteMagnetic fluxWavesGradientCarbonTemperatureNEURONTensorInteractionsEnergyMoleculesMolecularReconnectionPatternsSimulationTheoryHeatModerateFlowsCellElectrical
Equation9
  • ABSTRACT: In this electronic article we use the one-dimensional multigroup neutron diffusion equation to reconstruct the neutron flux in a slab reactor from the nuclear parameters of the reactor, boundary and symmetry condition, initial flux andkeff. (scirp.org)
  • The diffusion equation was solved analytically for one single homogeneous fuel region and for two regions considering fuel and reflector. (scirp.org)
  • This phenomenon is called molecular diffusion, and its mathematical aspect is captured by the diffusion equation. (wikipedia.org)
  • In this section a mathematical framework based on continuity equation is developed to describe the evolution of concentration profile over time, under action of eddy diffusion. (wikipedia.org)
  • For particles greater than 1μm in diameter typical dissolved species flux equation is no longer valid and shear-induced diffusion theory created by Zydney and Colton can be used. (citizendium.org)
  • Flow processes are described by diffusion equations (Darcy equation for groundwater flow, Richards equation for flow in the unsaturated zone, and the diffusive wave approximation for overland flow) which are coupled by exchange fluxes. (ufz.de)
  • This paper presents an analytical method for determining the exact solution of the time-resolved wall temperature during the engine cycle for any number of coating layers and properties using the Laplace transformed heat diffusion equation. (sae.org)
  • The method relies only on material properties and the past heat flux history, and represents the exact solution of the heat diffusion equation. (sae.org)
  • In early days, when people use central difference for both the first-oder convection term and the second-order diffusion terms, there were positive and negatice coefficients in the final equation. (cfd-online.com)
Advection-Diffusion Equations1
  • Transport processes are described by advection-diffusion equations and coupled with the exchange fluxes by advection. (ufz.de)
Equations5
  • Recent results on the numerical analysis of Algebraic Flux Correction (AFC) finite element schemes for scalar convection-diffusion equations are reviewed and presented in a unified way. (tib.eu)
  • A module for the ZEUS-2D code is described that may be used to solve the equations of radiation hydrodynamics to order unity in v/c, in the flux-limited diffusion (FLD) approximation. (princeton.edu)
  • The energy equations are operator split, with transport terms, radiation diffusion term, and other source terms evolved separately. (princeton.edu)
  • The individual ion fraction gradients and fluxes were computed, based on the Stefan-Maxwell equations for transport in a multicomponent system and the prerequisite that the ionic species should be at equilibrium at any point. (sintef.no)
  • It is possible to extend this technique to the case of interface problems, and it is in this context that the second project aims to develop the numerical analysis and implementation of such HDG methods for diffusion and convection-diffusion equations such as the Darcy and Oseen equations, coupling both in two sub-domains separated by a smooth interface. (lu.se)
Relativistic4
  • In this study, we use mutual information to characterise statistical dependencies of seed and relativistic electron fluxes in the Earth's radiation belts on ultra-low-frequency (ULF) wave power measured on the ground and at geostationary orbit. (copernicus.org)
  • 1998 ) that ULF wave power and relativistic electron fluxes are statistically dependent upon one another. (copernicus.org)
  • We also estimate that the Pearson correlation is missing between 20 % and 30 % of the statistical dependency between ULF wave power and relativistic electron fluxes. (copernicus.org)
  • The Lund string -- The confining force field between coloured partons is in the Lund string model [1] described by a "massless relativistic string", which represents an idealised picture of a flux tube with no transverse extension. (lu.se)
Coefficients1
  • We find that the electron dynamics agree well with the quasi‐linear theory diffusion coefficients for low amplitude incoherent waves with (B w,rms/B 0)2≈3.7·10−10, over a time scale T of the order of 1,000 gyroperiods. (bas.ac.uk)
Diapycnal3
  • We observed atypical evolution of the thermohaline stratification in comparison to most lakes due to the role of salt crystallization and diapycnal fluxes across lake layers. (hydroshare.org)
  • The diapycnal fluxes across the metalimnion were explained by Double Diffusion (DD) salt fingering driven by instability between warmer saltier water above cooler less salty water. (hydroshare.org)
  • The method estimates the up-gradient diapycnal buoyancy flux associated with double diffusion, which is hypothesised to balance the dissipation rate. (bas.ac.uk)
Radiation3
  • However, FLD is less accurate when the flux has a component perpendicular to the gradient in radiation energy density and in optically thin regions when the radiation field depends strongly on angle. (princeton.edu)
  • The radiation diffusion term is updated using an alternating direction-implicit method with convergence checking. (princeton.edu)
  • The high flux of coherent X-ray beams from synchrotron radiation facilities, combined with the nano-focus capabilities developed in recent years, have made it possible to probe nano-crystals. (lu.se)
Electron diffusion2
  • Abstract Kinetic structures of electron diffusion regions (EDRs) under finite guide fields in magnetotail reconnection are reported. (osti.gov)
  • Particle‐in‐cell experiments examine electron diffusion by whistler‐mode waves: 2. (bas.ac.uk)
Transmembrane8
  • Fouling of the membrane can still occur, along with concentration polarization, in which a gel layer forms and reduces transmembrane flux. (citizendium.org)
  • Concentration polarization can become exacerbated by gel formation in ultrafiltration systems, and microfiltration of suspended particles can create thick cake layers that reduce transmembrane flux. (citizendium.org)
  • [1] Large, soft particles can adhere to the pores, smaller particles can clog pores, and precipitates can form on the pores all reducing the pore size available and reducing transmembrane flux. (citizendium.org)
  • Quantitatively, filtration flux (J) across the membrane can be calculated by dividing the driving force (∆P m , typically the transmembrane pressure drop) by the overall membrane resistance (R G + R M ). The gel resistance, R G , usually increases with time until the membrane is cleaned, and the resistance of the membrane, R M , is often assumed to stay constant. (citizendium.org)
  • Membranes with small enough pore sizes, such as those used in ultrafiltration, can even remove dissolved species causing the formation of a gel layer that impedes transmembrane flux. (citizendium.org)
  • [1] The cake layer will continue to thicken, constricting the fluid flow channel and reducing the transmembrane flux of the filtrate. (citizendium.org)
  • Consequently, within this framework, the phase signal will be predominantly sensitive to any mechanism modifying the concentration of intracellular compounds, including transmembrane water movements, which accompany various ionic fluxes. (jneurosci.org)
  • In this study, we have taken advantage of the possibility of DHM to monitor transmembrane water fluxes as detected by the phase signal, to assess the activity of NKCC1 and KCC2 in response to depolarizations induced by glutamate on primary neurons in culture. (jneurosci.org)
Species2
  • hence, there is a net diffusion flux of aluminum-containing species toward the cathode. (sintef.no)
  • In order to overcome this, the biofilm growth in SSFs is modelled using a system of non-linear balance laws of convection-diffusion-reaction type with discontinuous flux for the concentration of species in the biofilm matrix and the flowing liquid suspension. (lu.se)
Proportional3
  • According to the gradient transport theory, the diffusion flux at a fixed point in the fluid is proportional to the local concentration gradient. (wikipedia.org)
  • This is described as the "gradient model" in a later section, the name derived from the fact that diffusion fluxes are proportional to the local gradient in concentration, just as for molecular diffusion. (wikipedia.org)
  • A fluid diffusion time is proportional to the time it takes for the fluid to diffuse throughout the sponge. (machinedesign.com)
Concentration6
  • By a purely probabilistic argument, the net flux of molecules from high concentration area to low concentration area is higher than the flux in the opposite direction. (wikipedia.org)
  • This down-gradient flux equilibrates the concentration profile over time. (wikipedia.org)
  • It is then derived that the concentration flux due to eddies is given by covariance of fluctuations in velocity and concentration. (wikipedia.org)
  • Diffusion[edit] Given the concentration and flux where D is the diffusion coefficient. (pearltrees.com)
  • Stratification at the top of Earth's core may have consequences for interpretations of the secular variation (SV), including magnetic flux concentration, diffusion, and dipole changes. (frontiersin.org)
  • This active transport creates a concentration gradient that favors the extracellular diffusion of potassium ions. (medscape.com)
Gradients3
Turbulent5
  • In fluid dynamics, eddy diffusion, eddy dispersion, or turbulent diffusion is a process by which fluid substances mix together due to eddy motion. (wikipedia.org)
  • In turbulent flows, on top of mixing by molecular diffusion, eddies stir (Eddy diffusion § Note on stirring and mixing) the fluid. (wikipedia.org)
  • The problem with turbulent diffusion in the atmosphere and beyond is that there is no single model drawn from fundamental physics that explains all its significant aspects. (wikipedia.org)
  • In particular, experiments on the diffusion of foreign material in a turbulent water stream, vertical structure of water in lake bodies, and lowest part of the atmosphere found experimental evidence that eddy diffusion is indeed stronger than molecular diffusion and generally obeys the theory originally developed by G. I. Taylor. (wikipedia.org)
  • Double diffusion refers to a variety of turbulent processes in which potential energy is released into kinetic energy, made possible in the ocean by the difference in molecular diffusivities between salinity and temperature. (bas.ac.uk)
Radial1
  • First, small radial energy fluxes are necessary for the plasma to achieve fusion-relevant conditions. (cern.ch)
Boundary layer1
  • Their results provide a model for the heat flux across the thermal boundary layer at the bottom of the mantle which favors thermal stratification at the top of Earth's and super-Earth's cores. (frontiersin.org)
Steady state2
  • In an ideal crossflow filtration system, the flux of permeate through the membrane will reach a steady state. (citizendium.org)
  • Steady state fluxes and lag times of diethyl phthalate (DEP, slightly volatile), 1,2-dichloroethane (DCE, highly volatile), and naphthalene (NAP, solid) were studied in two different laboratories using different analytical methods. (cdc.gov)
Algorithm1
Buoyancy1
  • In particular, these studies include eddy diffusion mechanisms to explain processes from aerosols deposition to internal gravity waves in the upper atmosphere, from deep sea eddy diffusion and buoyancy to nutrient supply to the surface of the mixed layer in the Antarctic Circumpolar Current. (wikipedia.org)
Scheme2
  • A general form of the method is presented using a link between AFC schemes and nonlinear edge-based diffusion scheme. (tib.eu)
  • All this says is, that for low Peclet numbers the discretization schemes must behave as thought diffusion is the dominant characteristic, while for high Peclet number the discretization scheme must behave as thought convection of the property is the dominant characteristic. (cfd-online.com)
Experimental1
  • The similarity between the overall shapes of the experimental and model-predicted flux/time curves and the successful simulation of altered system conditions for this series of small, lipophilic compounds indicated that the absorption processes that were described in the model successfully simulated important aspects of dermal absorption in flow-through cells. (cdc.gov)
Particles2
  • In contrast, statistical diffusion theories follow the motion of fluid particles, and are thus Lagrangian. (wikipedia.org)
  • The results indicate that the non-spherical particles produce higher critical fluxes than the spherical particles (i.e., respectively 24% and 13% higher for peanut and pear), which is caused by the looser packing in the cake due to the varied particle orientations. (bvsalud.org)
Processes2
  • Active research is now focused on the contributions of eddy diffusion to both atmospheric and oceanic known processes. (wikipedia.org)
  • The passive diffusion or active transport of water through the plasma membrane is associated with several cellular processes. (jneurosci.org)
Estimates1
  • 2018) showed that dissipation rates provide good estimates for heat fluxes in this region. (bas.ac.uk)
Mass2
  • They concluded that the transport of heat and mass transfer within the reactor is controlled by diffusion or natural convection. (hindawi.com)
  • Using NSE experiments, we observed a high internal flexibility of the intrinsically disordered MBP and the denatured BSA in addition to centre-of-mass diffusion detected by dynamic light scattering. (lu.se)
Finite3
  • For more accurate predictions of magnetic diffusion effects, 2D and 3D electromagnetic finite element analysis using software such as Maxwell 3D is recommended. (machinedesign.com)
  • The family of HDG methods is a type of finite element methods that use discontinuous basis functions constructed from local finite element spaces on each element, introducing an approximation of the trace of the solution on each inter-element boundary, and the prescription of a numerical flux across these. (lu.se)
  • A Memory-Efficient Finite Volume Method for Advection-Diffusion-Reaction Systems with Non-Smooth Sources , Num. (lu.se)
Magnetic flux7
  • The magnetic flux rises, delayed in part by a time constant called the magnetic diffusion time. (machinedesign.com)
  • Actuator force rises with the magnetic flux. (machinedesign.com)
  • When an electric current flows in its coil, a magnetic flux and magnetic force are produced, which cause the plunger to move towards the stationary stopper. (machinedesign.com)
  • Due to inductance L associated with the magnetic flux produced by the coil and its resistance R , the actuator is basically a series L-R circuit. (machinedesign.com)
  • However, inductance must usually be kept high to keep magnetic flux and force high. (machinedesign.com)
  • Similarly, magnetic flux produced by the current-carrying coil of Fig. 1 diffuses into the steel plunger and other solid steel parts during a magnetic diffusion time. (machinedesign.com)
  • The permeability µ of steel is only a constant value when the steel is operated at low magnetic flux density B in its linear B-H range, well below saturation. (machinedesign.com)
Waves2
  • Thus, the Pearson correlation underestimates the impact of ULF waves on energetic electron fluxes. (copernicus.org)
  • When waves form bubbles at the surface, carbon dioxide is transferred between the water and air (through diffusion). (lu.se)
Gradient1
Carbon1
  • Yellow numbers are natural fluxes, and red are human contributions in gigatons of carbon per year. (lu.se)
Temperature1
  • The DD flux is associated with: (1) sharpening of the metalimnion from a 20 m wide transition in early summer, to staircase, ultimately merging to a single sharp sub‐meter step, (2) salinity decline from the epilimnion starting from mid‐summer synchronous with increasing salinity and temperature of the hypolimnion, and (3) active halite crystallization in the hypolimnion. (hydroshare.org)
NEURON1
  • Extending NEURON to handle reaction-diffusion problems. (yale.edu)
Tensor1
Interactions1
  • The interest in this network arises from, among other applications, an application to wave-particle diffusion through resonant interactions in plasma. (princeton.edu)
Energy1
  • At the magnetic separatrices, the fluxes are smaller, but the energy spectra are harder and electrons are mainly field aligned. (esa.int)
Molecules1
  • 1][2][3] It allows the mapping of the diffusion process of molecules, mainly water, in biological tissues, in vivo and non-invasively. (pearltrees.com)
Molecular2
  • In most macroscopic flows in nature, eddy diffusion is several orders of magnitude stronger than molecular diffusion. (wikipedia.org)
  • The theory of eddy diffusion was originally developed, around the end of the 1910s, by G. I. Taylor and L. F. Richardson in England and by W. Schmidt in Austria as a direct generalization of the classical theory of molecular diffusion. (wikipedia.org)
Reconnection2
  • Reconnection electric fields E Y ~ 7 mV/m are observed within the diffusion region, whereas in the flux rope, E Y are much smaller. (esa.int)
  • We interpret the field-aligned electrons at the separatrices as directly accelerated by the reconnection electric field in the diffusion region, whereas we interpret the perpendicular electrons as trapped within the flux rope and accelerated by a combination of betatron acceleration with nonadiabatic pitch-angle scattering. (esa.int)
Patterns1
  • Anatomically accurate, 3-dimensional computational fluid dy- on major airflow patterns, air-phase diffusion, and absorption namics models of F344 rat, rhesus monkey, and human nasal at the air-lining interface. (cdc.gov)
Simulation1
  • The observed magnetic field and density indicate that the flux rope was very dynamic, and a comparison with numerical simulation suggests a crossing right after coalescence of smaller flux ropes. (esa.int)
Theory2
  • The theory of eddy diffusion was first developed by Sir Geoffrey Ingram Taylor. (wikipedia.org)
  • During the following decades, a number of studies were carried out to experimentally probe the established theory on eddy diffusion, both for the atmosphere and the ocean/lake bodies, mostly finding agreement with the original theory. (wikipedia.org)
Heat2
  • The influence of wall roughness on the wall heat flux is also studied, as it plays an important role for the lifespan of a rocket engine combustors. (springer.com)
  • A setup with and without film cooling is used, while the wall heat flux prediction is compared to the experiment. (springer.com)
Moderate2
  • 4α-methyl sterols derived from Methylococcales predominated in the surface layer at the BM site, which showed a moderate methane flux (0.04 mmol cm −2 y −1 ), while their occurrence was limited at the DM (0.06 mmol cm −2 y −1 ) and ST (0.01 mmol cm −2 y −1 ) sites. (nature.com)
  • For moderate field strengths, flux separation (FXS) is observed: isolated field-free inclusions of GRC are embedded in a strongly magnetized plasma with SSC. (aanda.org)
Flows1
  • We present observations of two consecutive current sheet crossings where the flux of electrons 35-127 keV peaks within an interval of tailward flows. (esa.int)
Cell2
  • While the Peclet Number is the Ratio of Convective to Diffusive Fluxes across the Cell. (cfd-online.com)
  • NO is also involved in cell kil ing but often used as a marker of oxidative Hanahan and Weinberg (2011), i n can also react with superoxide at DNA damage, although other bas- their landmark review "Hallmarks diffusion-limited rates to form per- es are also susceptible to oxidation. (who.int)
Electrical1
  • The magnetic diffusion time τ m is a time constant analogous to the electrical time constant τ e and thus flux turnon is delayed proportionally to τ m . (machinedesign.com)