Journal articles: 'Phase diffusion coefficient'

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Gordillo, Jorge A. "Effective Diffusion Coefficient." Defect and Diffusion Forum 384 (May 2018): 130–35. http://dx.doi.org/10.4028/www.scientific.net/ddf.384.130.

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The diffusion of a B element into an A matrix was studied by the random walk theory. Considering that concentration of B element in the A matrix is very low, the jumps of diffusing atoms are independent of each other. The A matrix is a two-region material with different properties, such as a two-phase material, a single crystal with dislocations, or regions influenced by other solute and a polycrystalline material.It is assumed that material B has a penetration that allows it to cross each region of material A several times. This implies that jumps across the surface between those regions have an average frequency and, as a consequence, there is an interdiffusion coefficient between them. The interdiffusion coefficient between those regions is different than the coefficient of the diffusion in each region.Expressions were obtained that allow to delimit the ranges of validation with greater precision than the corrected Hart-Mortlock equation for solute diffusion. In addition, an original relationship was obtained between the segregation coefficient and parameters specific to the diffusion. New powerful tools were also found that can help to understand diffusion in nanocrystalline materials, diffusion in metals influenced by impurities and diffusion produced by different mechanisms.

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Stloukal, Ivo, and Jiří Čermák. "Diffusion of Zinc in Two-Phase Mg-Al Alloy." Defect and Diffusion Forum 263 (March 2007): 189–94. http://dx.doi.org/10.4028/www.scientific.net/ddf.263.189.

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Coefficient of 65Zn heterodiffusion in Mg17Al12 intermetallic and in eutectic alloy Mg - 33.4 wt. % Al was measured in the temperature region 598 – 698 K using serial sectioning and residual activity methods. Diffusion coefficient of 65Zn in the intermetallic can be written as DI = 1.7 × 10-2 m2 s-1 exp (-155.0 kJ mol-1 / RT). At temperatures T ≥ 648 K, where the mean diffusion path was greater than the mean interlamellar distance in the eutectic, the effective diffusion coefficient Def = 2.7 × 10-2 m2 s-1 exp (-155.1 kJ mol-1 / RT) was evaluated. At two lower temperatures, the diffusion coefficients 65Zn in interphase boundaries were estimated: Db (623 K) = 1.6 × 10-12 m2 s-1 and Db (598 K) = 4.4 × 10-13 m2 s-1.

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Kale, G. B. "Thermodynamic Diffusion Coefficients." Defect and Diffusion Forum 279 (August 2008): 39–52. http://dx.doi.org/10.4028/www.scientific.net/ddf.279.39.

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A new form of diffusion coefficient termed as thermodynamic diffusion coefficient is introduced in this paper. Conventionally, diffusion coefficients are evaluated using concentration gradient as driving force. But truly, chemical potential gradient is the actual driving force that determines the material flow in any part of the system. Thermodynamic diffusion coefficients are based on chemical potential gradient as driving force. The relation between thermodynamic diffusion coefficients and phenomenological coefficients has been established. The advantages of thermodynamic diffusion coefficients have been underlined, especially, in the cases of line compounds where concentration difference across the phase is zero or in case of intermetallic compounds with narrow homogeneity range. The intrinsic thermodynamic diffusion coefficients are equal to tracer diffusion coefficients. This helps in estimating tracer diffusivities in cases where tracers are not easily available. The advantages of thermodynamic diffusion coefficients are shown in binary and ternary systems by illustrating them in Ni-Al and Fe-Ni-Cr systems.

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Elberling, Bo. "Gas phase diffusion coefficient in cemented porous media." Journal of Hydrology 178, no. 1-4 (April 1996): 93–108. http://dx.doi.org/10.1016/0022-1694(95)02808-0.

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Sridharan, S., and R. I. Cukier. "Effective diffusion coefficient of a two-phase material." Journal of Physical Chemistry 91, no. 11 (May 1987): 2962–69. http://dx.doi.org/10.1021/j100295a063.

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Liu, Zizhong, and Hamid Emami-Meybodi. "Diffusion-Based Modeling of Gas Transport in Organic-Rich Ultratight Reservoirs." SPE Journal 26, no. 02 (February 10, 2021): 857–82. http://dx.doi.org/10.2118/201393-pa.

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Summary The complex pore structure and storage mechanism of organic-rich ultratight reservoirs make the hydrocarbon transport within these reservoirs complicated and significantly different from conventional oil and gas reservoirs. A substantial fraction of pore volume in the ultratight matrix consists of nanopores in which the notion of viscous flow may become irrelevant. Instead, multiple transport and storage mechanisms should be considered to model fluid transport within the shale matrix, including molecular diffusion, Knudsen diffusion, surface diffusion, and sorption. This paper presents a diffusion-based semianalytical model for a single-component gas transport within an infinite-acting organic-rich ultratight matrix. The model treats free and sorbed gas as two phases coexisting in nanopores. The overall mass conservation equation for both phases is transformed into one governing equation solely on the basis of the concentration (density) of the free phase. As a result, the partial differential equation (PDE) governing the overall mass transport carries two newly defined nonlinear terms; namely, effective diffusion coefficient, De, and capacity factor, Φ. The De term accounts for the molecular, Knudsen, and surface diffusion coefficients, and the Φ term considers the mass exchange between free and sorbed phases under sorption equilibrium condition. Furthermore, the ratio of De/Φ is recognized as an apparent diffusion coefficient Da, which is a function of free phase concentration. The nonlinear PDE is solved by applying a piecewise-constant-coefficient technique that divides the domain under consideration into an arbitrary number of subdomains. Each subdomain is assigned with a constant Da. The diffusion-based model is validated against numerical simulation. The model is then used to investigate the impact of surface and Knudsen diffusion coefficients, porosity, and adsorption capacity on gas transport within the ultratight formation. Further, the model is used to study gas transport and production from the Barnett, Marcellus, and New Albany shales. The results show that surface diffusion significantly contributes to gas production in shales with large values of surface diffusion coefficient and adsorption capacity and small values of Knudsen diffusion coefficient and total porosity. Thus, neglecting surface diffusion in organic-rich shales may result in the underestimation of gas production.

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Yarimitsu, Masakazu, and Masaru Aniya. "A Molecular Dynamics Study on Pressure Dependence of Ag Diffusion in Ag₃SI." Advances in Science and Technology 72 (October 2010): 337–42. http://dx.doi.org/10.4028/www.scientific.net/ast.72.337.

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The pressure dependence of the diffusion coefficient in the superionic α- and β-phases of Ag3SI has been studied by using the method of molecular dynamics. It is shown that in the high temperature α-phase, the Ag diffusion coefficient decreases with pressure. On the hand, in the intermediate temperature β-phase, the Ag diffusion coefficient exhibits a maximum at around 2.8 GPa. The structural origin of this behavior is discussed through the pressure dependence of the pair distribution functions.

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Vasilev, A. N. "A Model of Gas Diffusion in a Metal Plate with Phase Transformation." Ukrainian Journal of Physics 64, no. 4 (May 16, 2019): 348. http://dx.doi.org/10.15407/ujpe64.4.348.

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A model of gas diffusion in a metal plate has been proposed, in which a phase transformation “metal–gassed metal” takes place, when the gas concentration exceeds a certain critical value, and the properties of the system change qualitatively. The phase transformation is modeled by changing the coefficient of gas diffusion. In particular, a system of two phases with different diffusion coefficients and a moving interface between them is considered. The gas concentrations in both phases at the interface are assumed to be the known constants. An analytical solution is obtained in the approximation that the diffusion in the metal phase (the initial state of a metal layer) is much quicker than that in the gassed-metal one, with the both being much quicker than the motion of the phase interface. In the framework of this model, the spatial distribution of the gas concentration in the gassed-metal phase is calculated, and the analytic formula describing the motion of a phase interface is derived.

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Toivola, J., P. O. Michel, L. Gilbert, T. Lahtinen, V. Marjomäki, K. Hedman, M. Vuento, and C. Oker-Blom. "Monitoring human parvovirus B19 virus-like particles and antibody complexes in solution by fluorescence correlation spectroscopy." Biological Chemistry 385, no. 1 (January 5, 2004): 87–93. http://dx.doi.org/10.1515/bc.2004.011.

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AbstractFluorescence correlation spectroscopy (FCS) was used in monitoring human parvovirus B19 virus-like particle (VLP) antibody complexes from acute phase and pastimmunity serum samples. The Oregon Green 488-labeled VLPs gave an average diffusion coefficient of 1.7x10exp-7 cm(2)s(-1) with an apparent hydrodynamic radius of 14 nm. After incubation of the fluorescent VLPs with an acute phase serum sample, the mobility information obtained from the fluorescence intensity fluctuation by autocorrelation analysis showed an average diffusion coefficient of 1.5x10exp-8 cm(2)s(-1), corresponding to an average radius of 157 nm. In contrast, incubation of the fluorescent VLPs with a pastimmunity serum sample gave an average diffusion coefficient of 3.5x10exp-8 cm(2)s(-1) and a radius of 69 nm. A control serum devoid of B19 antibodies caused a change in the diffusion coefficient from 1.7x10exp-7 to 1.6x10exp-7 cm(2)s(-1), which is much smaller than that observed with acute phase or pastimmunity sera. Thus, VLP-antibody complexes with different diffusion coefficients could be identified for the acute phase and pastimmunity sera. FCS measurement of VLPimmune complexes could be useful in distinguishing between antibodies present in acute phase or past-immunity sera as well as in titration of the VLPs.

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Komiya, Atsuki, Juan F. Torres, and Shigenao Maruyama. "Measurement of Mass Diffusion Coefficient of Multi-Component System in Aqueous Media by Phase Shifting Interferometer." Defect and Diffusion Forum 297-301 (April 2010): 624–30. http://dx.doi.org/10.4028/www.scientific.net/ddf.297-301.624.

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This paper describes a novel technique to determine mass diffusion coefficients of multi-component system within a transparent mixture by using an optical system. The mixture is composed of sodium chloride and lysozyme as solutes. Binary and multi-component solution experiments were conducted separately under constant temperature conditions. By measuring transient diffusion fields inside the cell, as well as for mixed multi-component solutions, it was confirmed that within the concentration ranges considered in this study, the diffusion of each solute inside the cell progresses independently. This indicates the superposition principle of concentration for certain levels of sodium chloride and lysozyme within the cell. Furthermore, by using this concentration superposition principle and an inverse analysis based on the conjugate gradient method, the diffusion coefficients of each solute in the mixture were successfully obtained from several multi-component experiments. Each obtained diffusion coefficient was good agreement with the determined diffusion coefficient from binary experiment.

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O'Doherty, Fergal, and James P. Gleeson. "Phase Diffusion Coefficient for Oscillators Perturbed by Colored Noise." IEEE Transactions on Circuits and Systems II: Express Briefs 54, no. 5 (May 2007): 435–39. http://dx.doi.org/10.1109/tcsii.2007.892203.

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Miyabe, Kanji, and Shigeya Takeuchi. "Estimation of surface diffusion coefficient in liquid phase adsorption." Canadian Journal of Chemical Engineering 76, no. 5 (October 1998): 887–92. http://dx.doi.org/10.1002/cjce.5450760505.

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13

Chvoj, Z. "The surface collective diffusion coefficient and diffuse phase transformations." Journal of Statistical Mechanics: Theory and Experiment 2008, no. 08 (August 8, 2008): P08002. http://dx.doi.org/10.1088/1742-5468/2008/08/p08002.

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Tian, Zhiyu, Yang Liu, and Le Luo. "Shannon Entropy and Diffusion Coefficient in Parity-Time Symmetric Quantum Walks." Entropy 23, no. 9 (August 31, 2021): 1145. http://dx.doi.org/10.3390/e23091145.

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Non-Hermitian topological edge states have many intriguing properties, however, to date, they have mainly been discussed in terms of bulk–boundary correspondence. Here, we propose using a bulk property of diffusion coefficients for probing the topological states and exploring their dynamics. The diffusion coefficient was found to show unique features with the topological phase transitions driven by parity–time (PT)-symmetric non-Hermitian discrete-time quantum walks as well as by Hermitian ones, despite the fact that artificial boundaries are not constructed by an inhomogeneous quantum walk. For a Hermitian system, a turning point and abrupt change appears in the diffusion coefficient when the system is approaching the topological phase transition, while it remains stable in the trivial topological state. For a non-Hermitian system, except for the feature associated with the topological transition, the diffusion coefficient in the PT-symmetric-broken phase demonstrates an abrupt change with a peak structure. In addition, the Shannon entropy of the quantum walk is found to exhibit a direct correlation with the diffusion coefficient. The numerical results presented herein may open up a new avenue for studying the topological state in non-Hermitian quantum walk systems.

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Kumar, Rajneesh, and Tarun Kansal. "Viscosity and Diffusion Effects at the Boundary Surface of Viscous Fluid and Thermoelastic Diffusive Solid Medium." Advances in Applied Mathematics and Mechanics 3, no. 2 (April 2011): 219–38. http://dx.doi.org/10.4208/aamm.10-m1016.

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AbstractThis paper concentrates on the wave motion at the interface of viscous compressible fluid half-space and homogeneous isotropic, generalized thermoelastic diffusive half-space. The wave solutions in both the fluid and thermoelastic diffusive half-spaces have been investigated; and the complex dispersion equation of leaky Rayleigh wave motion have been derived. The phase velocity and attenuation coefficient of leaky Rayleigh waves have been computed from the complex dispersion equation by using the Muller’s method. The amplitudes of displacements, temperature change and concentration have been obtained. The effects of viscosity and diffusion on phase velocity and attenuation coefficient of leaky Rayleigh waves motion for different theories of thermoelastic diffusion have been depicted graphically. The magnitude of heat and mass diffusion flux vectors for different theories of thermoelastic diffusion have also been computed and represented graphically.

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AFZALI, R., and F. PASHAEE. "SPIN DIFFUSION COEFFICIENT OF A1-PHASE OF SUPERFLUID 3He AT LOW TEMPERATURES." Modern Physics Letters B 23, no. 12 (May 20, 2009): 1603–10. http://dx.doi.org/10.1142/s0217984909019752.

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The spin diffusion coefficient tensor of the A1-phase of superfluid 3 He at low temperatures and melting pressure is calculated using the Boltzmann equation approach and Pfitzner procedure. Then considering Bogoliubov-normal interaction, we show that the total spin diffusion is proportional to 1/T2, the spin diffusion coefficient of superfluid component [Formula: see text] is proportional to T-2, and the spin diffusion coefficient of super-fluid component [Formula: see text] is independent of temperature. Furthermore, it is seen that superfluid components play an important role in spin diffusion of the A1-phase.

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Thøgersen, Kjetil, and Marcin Dabrowski. "Mixing of the fluid phase in slowly sheared particle suspensions of cylinders." Journal of Fluid Mechanics 818 (April 6, 2017): 807–37. http://dx.doi.org/10.1017/jfm.2017.159.

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We introduce a finite element model for neutrally buoyant particle suspensions of cylinders at zero Reynolds number and infinite Péclet number in the purely hydrodynamic limit, which allows us to access a high-accuracy fluid velocity field at any time during the simulation. We use the diffusive strip method to characterize the development of the concentration field in the fluid phase of sheared suspensions from initial thin filaments, and characterize the structures that form with their fractal dimension. We find that the growth of the fractal dimension of the filaments scales with the increase of mean square displacement in the fluid phase. Further, we measure the concentration distribution of tracers in the fluid phase, as well as the shear-induced self-diffusion coefficient in both the solid phase and the fluid phase. We demonstrate that the shear-induced self-diffusion coefficient is slightly larger in the fluid phase at infinite Péclet number. Finally, we investigate enhanced mass diffusivity in the fluid phase by systematic measurements of the shear-induced self-diffusion coefficient in the fluid phase for a wide range of fluid tracer Péclet numbers. We find that the functional dependence $D_{s}/D=1+\unicode[STIX]{x1D6FD}\unicode[STIX]{x1D719}^{\unicode[STIX]{x1D6FC}}Pe^{\unicode[STIX]{x1D701}}$ (where $D_{s}$ is the shear-induced self-diffusion coefficient, $D$ is the molecular diffusivity and $\unicode[STIX]{x1D719}$ is the particle volume fraction) fits the observations fairly well. We measure the constants $\unicode[STIX]{x1D6FD}=2.98\pm 0.39$, $\unicode[STIX]{x1D6FC}=1.61\pm 0.26$ and $\unicode[STIX]{x1D701}=0.900\pm 0.031$.

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Sikame Tagne, N. R., E. Njeugna, M. Fogue, J. Y. Drean, A. Nzeukou, and D. Fokwa. "Study of Water Absorption in RaffiaviniferaFibres from Bandjoun, Cameroon." Scientific World Journal 2014 (2014): 1–11. http://dx.doi.org/10.1155/2014/912380.

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The study is focused on the water diffusion phenomenon through the Raffiaviniferafibre from the stem. The knowledge on the behavior of those fibres in presence of liquid during the realization of biocomposite, is necessary. The parameters like percentage of water gain at the point of saturation, modelling of the kinetic of water absorption, and the effective diffusion coefficient were the main objectives. Along a stem of raffia, twelve zones of sampling were defined. From Fick’s 2nd law of diffusion, a new model was proposed and evaluated compared to four other models at a constant temperature of 23°C. From the proposed model, the effective diffusion coefficient was deduced. The percentage of water gain was in the range of 303–662%. The proposed model fitted better to the experimental data. The estimated diffusion coefficient was evaluated during the initial phase and at the final phase. In any cross section located along the stem of Raffiavinifera, it was found that the effective diffusion coefficient increases from the periphery to the centre during the initial and final phases.

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Hickey, Owen A., Jean-François Mercier, Michel G. Gauthier, Frédéric Tessier, Smaine Bekhechi, and Gary W. Slater. "Effective molecular diffusion coefficient in a two-phase gel medium." Journal of Chemical Physics 124, no. 20 (May 28, 2006): 204903. http://dx.doi.org/10.1063/1.2198204.

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Radi, Z., J. L. Lábár, and P. B. Barna. "Diffusion coefficient of Al in metastable, amorphous Al–Pt phase." Applied Physics Letters 73, no. 22 (November 30, 1998): 3220–22. http://dx.doi.org/10.1063/1.122724.

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Lee, Byeong-Joo. "Evaluation of off-diagonal diffusion coefficient from phase diagram information." Journal of Phase Equilibria 22, no. 3 (May 2001): 241–46. http://dx.doi.org/10.1361/105497101770338716.

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Satyawali, P. K. "Diffusivity and vapor flow into snow during phase change." Annals of Glaciology 31 (2000): 445–50. http://dx.doi.org/10.3189/172756400781820101.

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AbstractLarge variations in values of the diffusion coefficient for snow have been reported in the literature. Some authors (Yosida and others, 1955; Yen, 1963) have claimed that the diffusion coefficient does not vary with density. Others (Colbeck, 1993; Arons and Colbeck, 1995) have reported that the diffusion coefficient decreases with an increase in mean pore length, and that it does not necessarily change with snow density. This appears to be inconsistent, since density and mean pore space are related for a given mass of snow and therefore these parameters cannot be taken independently. On the other hand, experimental results show an increase in grain-growth rate with decrease in snow density. In this paper, particulate and continuum approaches have been used to obtain the mass diffusivity Treating snow as a particulate medium, the one-dimensional model of grain growth from Satyawali (1994) has been extended. This approach has been integrated into the SNOWPACK model (Lehning and others, 1998) that predicts the rate of grain growth for a dry snowpack subject to a temperature gradient. The expression for effective vapor-diffusion coefficient resulting from the present study isTo test this equation, several experiments similar to those of Yosida and others (1955) have been conducted assuming that snow is a continuous medium. In this approach Fick’s law of diffusion is used to obtain direct experimental determinations of the diffusion coefficient. The experimental results have been compared to estimates of D∊ calculated from the above equation and it is shown that results are inconsistent at the upper and lower sample boundaries. This paper describes the features of snow metamorphism, in particular grain growth driven by an applied temperature gradient, and discusses the mass-diffusivity coefficient derived from the particle theory of Colbeck (1993).

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Setapa, Amanina, Naveed Ahmad, Shalela Mohd Mahali, and Mohd Cairul Iqbal Mohd Amin. "Mathematical Model for Estimating Parameters of Swelling Drug Delivery Devices in a Two-Phase Release." Polymers 12, no. 12 (December 5, 2020): 2921. http://dx.doi.org/10.3390/polym12122921.

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Various swelling drug delivery devices are promising materials for control drug delivery because of their ability to swell and release entrapped therapeutics, in response to physiological stimuli. Previously, many mathematical models have been developed to predict the mechanism of drug release from a swelling device. However, some of these models do not consider the changes in diffusion behaviour as the device swells. Therefore, we used a two-phase approach to simplify the mathematical model considering the effect of swelling on the diffusion coefficient. We began by defining a moving boundary problem to consider the swelling process. Landau transformation was used for mitigating the moving boundary problem. The transformed problem was analytically solved using the separation of variables method. Further, the analytical solution was extended to include the drug release in two phases where each phase has distinct diffusion coefficient and continuity condition was applied. The newly developed model was validated by the experimental data of bacterial cellulose hydrogels using the LSQCURVEFIT function in MATLAB. The numerical test showed that the new model exhibited notable improvement in curve fitting, and it was observed that the initial effective diffusion coefficient of the swelling device was lower than the later effective diffusion coefficient.

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Mostafa, A. A. "Turbulent Diffusion of Heavy-Particles in Turbulent Jets." Journal of Fluids Engineering 114, no. 4 (December 1, 1992): 667–71. http://dx.doi.org/10.1115/1.2910083.

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The turbulent dispersion of heavy suspended particles in turbulent shear flows is analyzed when crossing trajectory effects are important. A semiempirical expression for particle diffusion coefficient is developed via a comparison with experimental data of two-phase turbulent jet flows. This expression gives the particle momentum diffusion coefficient in terms of the gas diffusion coefficient, mean relatively velocity, and root mean square of the fluctuating fluid velocity. The proposed expression is used in a two-phase flow mathematical model to predict different particle-laden jet flows. The good agreement between the predictions and data suggests that the developed expression for particle diffusion coefficient is reasonably accurate in predicting particle dispersion in turbulent free shear flows.

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Sankar, D. S., Nurul Aini Jaafar, and Yazariah Yatim. "Unsteady solute dispersion in blood rheology with reversible phase exchange at the artery wall." International Journal of Engineering & Technology 7, no. 2 (May 17, 2018): 750. http://dx.doi.org/10.14419/ijet.v7i2.11527.

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The effect of reversible phase exchange between the flowing fluid and wall tissues of arteries in the unsteady dispersion of solute in blood flow through a narrow artery is analysed mathematically, modelling the blood as Casson fluid. The resulting convective diffusion equation along with the initial and boundary conditions is solved analytically using the derivative series expansion method. The expressions for the negative asymptotic phase exchange, negative asymptotic convection, longitudinal diffusion coefficient and mean concentration are obtained. It is noted that when the solute disperses in blood flow through a narrow artery, the negative exchange coefficient, the negative convection coefficient increase and the longitudinal diffusion coefficient decreases with the increase of the Damköhler number and partition coefficient.

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Nowok, J. W. "A model of diffusion/viscous mass transport in silicates during liquid-phase sintering." Journal of Materials Research 10, no. 2 (February 1995): 401–4. http://dx.doi.org/10.1557/jmr.1995.0401.

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The model of capillary transport of liquid metals driven by shear stress resulting from the displacement of menisci [J.W. Nowok, Scripta Metal]. Mater. 29, 931 (1993); Acta Metall. Mater. 42, 4025 (1994)] is applicable to liquid-phase sintering of silicate/aluminosilicate glasses. The movement of a liquid phase between adjacent particles is compared with that in capillaries. It appears that the transport property of intergranular melt may be expressed by the viscosity (η) and volume diffusion (D) parameters if mean displacement of menisci is compared with the mean diffusive jump lengths of atoms/molecules (L). This leads to the following relation: (γ/η)Lα = Dcap, where α and Dcap are a specific permeability and volume diffusion coefficient. The use of this model requires the assumption that the diffusing species are also the viscous flow units, and they can be either atoms or structural units. This assumption seems to be applicable for depolymerized silicate melts if the dominant mass transport is initiated by the diffusion of both nonbridging oxygen and silicon atoms.

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Tas Kavakbasi, Bengü, Igor S. Golovin, Aloke Paul, and Sergiy V. Divinski. "On the Analysis of Composition Profiles in Binary Single-Phase Diffusion Couples: Systems with a Strong Compositional Dependence of the Interdiffusion Coefficient." Defect and Diffusion Forum 383 (February 2018): 23–30. http://dx.doi.org/10.4028/www.scientific.net/ddf.383.23.

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Diffusion couple technique is an efficient tool for the estimating the chemical diffusion coefficients. Typical experimental uncertainties of the composition profile measurements complicate a correct determination of the interdiffusion coefficients via the standard Boltzmann-Matano, Sauer-Freise or the den Broeder methods, especially for systems with a strong compositional dependence of the interdiffusion coefficient. A new approach for reliable fitting of the experimental profiles with an improved behavior at both ends of the diffusion couple is proposed and tested against the experimental data on chemical diffusion in the system Fe-Ga. An extension of the approach for reliable description of the up-hill diffusion phenomenon in multicomponent systems is presented.

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Park, Jong Hyun, Hana Yoon, Younghyun Cho, and Chung-Yul Yoo. "Investigation of Lithium Ion Diffusion of Graphite Anode by the Galvanostatic Intermittent Titration Technique." Materials 14, no. 16 (August 19, 2021): 4683. http://dx.doi.org/10.3390/ma14164683.

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Graphite is used as a state-of-the-art anode in commercial lithium-ion batteries (LIBs) due to its highly reversible lithium-ion storage capability and low electrode potential. However, graphite anodes exhibit sluggish diffusion kinetics for lithium-ion intercalation/deintercalation, thus limiting the rate capability of commercial LIBs. In order to determine the lithium-ion diffusion coefficient of commercial graphite anodes, we employed a galvanostatic intermittent titration technique (GITT) to quantify the quasi-equilibrium open circuit potential and diffusion coefficient as a function of lithium-ion concentration and potential for a commercial graphite electrode. Three plateaus are observed in the quasi-equilibrium open circuit potential curves, which are indicative of a mixed phase upon lithium-ion intercalation/deintercalation. The obtained diffusion coefficients tend to increase with increasing lithium concentration and exhibit an insignificant difference between charge and discharge conditions. This study reveals that the diffusion coefficient of graphite obtained with the GITT (1 × 10−11 cm2/s to 4 × 10−10 cm2/s) is in reasonable agreement with literature values obtained from electrochemical impedance spectroscopy. The GITT is comparatively simple and direct and therefore enables systematic measurements of ion intercalation/deintercalation diffusion coefficients for secondary ion battery materials.

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Wrana, Bogumił. "Dynamics Coefficient for Two-Phase Soil Model." Studia Geotechnica et Mechanica 36, no. 2 (February 28, 2015): 51–56. http://dx.doi.org/10.2478/sgem-2014-0020.

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Abstract The paper investigates a description of energy dissipation within saturated soils-diffusion of pore-water. Soils are assumed to be two-phase poro-elastic materials, the grain skeleton of which exhibits no irreversible behavior or structural hysteretic damping. Description of motion and deformation of soil is introduced as a system of equations consisting of governing dynamic consolidation equations based on Biot theory. Selected constitutive and kinematic relations for small strains and rotation are used. This paper derives a closed form of analytical solution that characterizes the energy dissipation during steady-state vibrations of nearly and fully saturated poro-elastic columns. Moreover, the paper examines the influence of various physical factors on the fundamental period, maximum amplitude and the fraction of critical damping of the Biot column. Also the so-called dynamic coefficient which shows amplification or attenuation of dynamic response is considered.

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Mohsun, Mohammed Kasim. "Influence of Phases Stability on the Hydrogen Diffusion Coefficient in Ti-6Al-4V." Materials Science Forum 986 (April 2020): 33–40. http://dx.doi.org/10.4028/www.scientific.net/msf.986.33.

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For a unique microstructure creation, thermo-hydrogen treatment (THT), using hydrogen as a temporary alloying element within the heat treatment, is applied. This advanced heat treatment requires reliable data about the hydrogen diffusion coefficient (DH) for understanding diffusion kinetics and its effect on the mechanical behavior of the resulted phases. In this research, three different homogeneous microstructures were established for the investigation using different homogenization parameters. After that, the concentration of hydrogen, charged in the half-length of thin titanium rods via electrochemical hydrogenation, is specified. Then, a diffusion annealing heat treatment was carried out at different temperatures, leading to hydrogen diffusion in the hydrogenated specimens. Furthermore, DH was systematically determined using two methods including the explicit finite difference method (EFDM) and Matano technique (MT). For this purpose, Abaqus software was employed for modeling the hydrogen gradient established in the specimens. Additionally, scanning electron microscopy (SEM) was used for the microstructure examination in order to specify the influence of different hydrogen concentrations on the hydrogenated specimens. The experimental outcomes reveal a substantial effect of the β phase stability and grains sizes of the β and α phases on the hydrogen diffusion. Correspondingly, the results confirm that DH was independent of the hydrogen concentration, and obeys an Arrhenius-type temperature dependence. Furthermore, hydrogen diffusion in the α+β titanium alloys Ti-6Al-4V was slower in comparison to the hydrogen diffusion in the metastable β titanium alloys Ti-10V-2Fe-3Al. In conclusion, it was observed that DH is influenced by the previously performed heat treatments that determine the resulted microstructure types, and a slight influence of the volume fraction of the α phase on DH was observed as well.

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Zheng, Jia Jin, Shi Lang Xu, and Xin Zhu Zhou. "Effect of Interfacial Transition Zone on Chloride Diffusion Coefficient." Key Engineering Materials 302-303 (January 2006): 167–74. http://dx.doi.org/10.4028/www.scientific.net/kem.302-303.167.

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A three-phase composite circle model is presented in this paper to assess the effect of interfacial transition zone (ITZ) on the chloride diffusion coefficient of concrete. Firstly, the distribution of circular aggregate particles was simulated in a square concrete element. Based on the simulated concrete mesostructure, the Monte Carlo algorithm was adopted to numerically evaluate the ITZ area fraction for different concrete mixes. A parametric study was then conducted to quantify the effects of the largest aggregate diameter, ITZ thickness and aggregate gradation on the ITZ area fraction. Secondly, the ITZ was modeled as a thin-wall annular plate located between a circular aggregate particle and a thick-wall cement paste annular plate. With the three-phase composite circle model, an analytical solution was derived for the chloride diffusion coefficient of concrete. Finally, the derived solution was verified by experimental results obtained from the research literature and a quantitative relationship between the thickness and chloride diffusion coefficient of ITZ was established.

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Pacheco-Roman, Francisco J., and S. Hossein Hejazi. "Estimation of Solubility and Diffusivity of Gases in Heavy Oils by Use of Late-Time Pressure-Decay Data: An Analytical/Graphical Approach." SPE Journal 20, no. 04 (August 20, 2015): 717–28. http://dx.doi.org/10.2118/170957-pa.

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Summary Solubility and diffusivity of gases in heavy oils, quantified by Henry's constant (Hij) and the diffusion coefficient (D), respectively, are essential properties for the design of recovery processes that require the injection of gas or vapor solvents into the reservoir. Data, obtained from various experimental procedures such as the pressure-decay technique (PDT), are used to estimate these two parameters. The PDT uses a pressure/volume/temperature (PVT) cell where the gas-phase pressure declines as gas diffuses into heavy oil following an early- and a late-time regime. Current approaches to analyze data from the conventional PDT are either graphical techniques based on early-time data or full numerical simulation. Early-time data, when the diffusing gas has not reached the bottom of the PVT cell, do not provide enough information to simultaneously estimate both the diffusion coefficient and Henry's constant. Hence, existing graphical procedures are limited to diffusion-coefficient estimation. In this paper, we propose a novel graphical technique to estimate the diffusion coefficient and Henry's constant by use of the late-time data from pressure-decay experiments. Our method is derived from the modeling of gas-phase pressure decay by use of Fick's second law and gas-phase mass-balance equations. We use the integral method to provide an approximate analytical solution to the set of equations. In addition, by use of the resultant solution, we develop a simple graphical method to directly estimate both the diffusion coefficient and Henry's constant. The estimated parameters through the proposed technique for methane/bitumen and carbon dioxide/bitumen experiments are in close agreement with those reported in the literature.

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Wang, Nan, Xiao Wang, and Wen Jing Yao. "The Contribution of Diffusion Coefficient to the Eutectic Instability and Amorphous Phase Formation." Materials Science Forum 654-656 (June 2010): 1355–58. http://dx.doi.org/10.4028/www.scientific.net/msf.654-656.1355.

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The diffusion coefficient D decides the diffusion length of solute boundary and plays a key role in the microstructure selection. This paper examines quantitatively the contribution of diffusion coefficient to the eutectic instability and amorphorization ability. The maximum growth velocity Vmax and the maximum undercooling Tmax as functions of activation energy Q in strong liquids are deduced theoretically based on eutectic growth model by separating Q from D. It reveals that the larger the Q, the smaller the Tmax and Vmax, which shows the same tendency as experimental values in some Al-based alloys and glass formers. This indicates that it is the sluggish movement of atoms that makes the transition from eutectic to others structural morphologies, even to amorphous phase, occur at smaller interface growth velocity or undercooling, which is the main contribution of the diffusion coefficient to the amorphorization ability.

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Laik, A., K. Bhanumurthy, and G. B. Kale. "Diffusion in Cu(Al) Solid Solution." Defect and Diffusion Forum 279 (August 2008): 63–69. http://dx.doi.org/10.4028/www.scientific.net/ddf.279.63.

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The solid state diffusion characteristics in the Cu(Al) solid solution phase, was investigated in the temperature range of 1023–1223 K using single phase bulk diffusion couples between pure Cu/Cu- 10 at.% Al. The interdiffusion coefficients, D, were calculated using Boltzmann–Matano method and Hall’s method from the concentration profiles of the couples that were determined using EPMA. The interdiffusion coefficients (D) calculated ranges between 1.39 X 10−14 and 3.97 X 10−13 m2/s in the temperature range of 1023 to 1223 K. The composition and temperature dependence of D were established. The activation energy for interdiffusion varies from 123.1 to 134.2 kJ/mol in the concentration range 1 at. % ≤ CAl ≤ 9 at. %. The impurity diffusion coefficient of Al in Cu is determined by extrapolating the interdiffusion coeffficient values to infinite dilution of the alloy i.e CAl →0 and its temperature dependence was also established. The activation energy for impurity diffusion of Al in Cu was found to be 137.1 kJ/mol.

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Wang, H., D. Vedapuri, J. Y. Cai, T. Hong, and W. P. Jepson. "Mass Transfer Coefficient Measurement in Water/Oil/Gas Multiphase Flow." Journal of Energy Resources Technology 123, no. 2 (November 10, 2000): 144–49. http://dx.doi.org/10.1115/1.1368121.

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Mass transfer studies in oil-containing multiphase flow provide fundamental knowledge towards the understanding of hydrodynamics and the subsequent effect on corrosion in pipelines. Mass transfer coefficient measurements in two-phase (oil/ferri-ferrocyanide) and three-phase (oil/ferri-ferrocyanide/nitrogen) flow using limiting current density technique were made in 10-cm-dia pipe at 25 and 75 percent oil percentage. Mass transfer coefficients in full pipe oil/water flow and slug flow were studied. A relationship is developed between the average mass transfer coefficient in full pipe flow and slug flow. The mass transfer coefficient decreased with a decrease of in-situ water cut. This was due to the existence of oil phase, which decreased the ionic mass transfer diffusion coefficient.

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Avazkonandeh-Gharavol, M. H., M. Haddad-Sabzevar, and H. Fredriksson. "Analysis of phase diagram and diffusion coefficient for modeling of microsegregation." Journal of Materials Science 52, no. 3 (September 28, 2016): 1446–60. http://dx.doi.org/10.1007/s10853-016-0438-y.

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Bae, Deuck Seung, and Woo Sang Jung. "Precipitation Behavior of MN(M=V,Nb) Phase in the 7Cr-1.5Mo Ferritic Heat Resistant Steels." Advanced Materials Research 26-28 (October 2007): 1093–96. http://dx.doi.org/10.4028/www.scientific.net/amr.26-28.1093.

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The relationship between precipitation behavior of MX(M=V, Nb) nitrides and mechanical property during aging in 7Cr-1.5Mo ferritic heat resistant steels were investigated in this study. Artificial aging was carried out at 700°C for different time from 100 to 10000 hours to simulate the environment of fossil power plant. The Ostwald ripening equation is related to the containing elements can explain the accelerated coarsening of MX in the model alloys. The Ostwald ripening equation was modified by introducing the effective diffusion coefficient as a sum of the lattice diffusion coefficient and dislocation diffusion coefficient, based on an assumption that V, Nb and Ti might diffuse not only by the lattice diffusion mechanism but also by the dislocation diffusion mechanism.

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Zhang, Ying-Yi, Yun-Gang Li, Xue-Feng Shi, and Yuan-Hong Qi. "Effect of Liquid-phase Siliconizing Process on Silicon Diffusion Behavior in Mo Matrix." High Temperature Materials and Processes 33, no. 5 (September 29, 2014): 421–26. http://dx.doi.org/10.1515/htmp-2013-0093.

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AbstractMoSi2 functionally graded coating on Mo substrate is prepared by liquid-phase siliconizing technology. The SEM, GDS and XRD analysis shows that the silicon content in gradient layer appears in three changing regularities. Along the Mo substrate to the surface of the coating, the phase composition of gradient coating changes as follows: Mo → transition layer Mo (main phase) + Mo3Si + Mo5Si3 → intermediate layer MoSi2 → surface layer MoSi2 (main phase) + Si. According to the Si-Mo diffusion couple and Arrhenius equation, the activation energy (Q) was obtained as 430 kJ·mol−1, and the Arrhenius dependence of D on temperature can be described as D = 4.9 × 10−3 exp(−430000/RT) m2/s. The diffusion temperature has an important influence on silicon diffusion coefficient. As the diffusion temperature increases, silicon diffusion coefficient is also gradually increasing.

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39

WU, SIZHU, JUN YI, LISHU ZHANG, LIQUN ZHANG, and JAMES E. MARK. "THE STUDY ON THE GAS PERMEABILITIES OF THE ETHYLENE/1-HEXENE COPOLYMER BY MOLECULAR DYNAMICS SIMULATION." International Journal of Modern Physics B 22, no. 31n32 (December 30, 2008): 5859–64. http://dx.doi.org/10.1142/s0217979208051285.

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In this research, molecular dynamics(MD) simulations were used to study the transport properties of small gas molecules in poly(ethylene-co-1-hexene) copolymer. The condensed-phase optimized molecular potentials for atomistic simulation studies (COMPASS) forcefield was applied. The diffusion coefficients were obtained from MD (NVT ensemble). The results indicated that the diffusion coefficient of oxygen increased with increasing 1-hexene content in copolymer membrane.

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Langenberg, Stefan, Torsten Carstens, Dirk Hupperich, Silke Schweighoefer, and Ulrich Schurath. "Technical note: Determination of binary gas-phase diffusion coefficients of unstable and adsorbing atmospheric trace gases at low temperature – arrested flow and twin tube method." Atmospheric Chemistry and Physics 20, no. 6 (March 26, 2020): 3669–82. http://dx.doi.org/10.5194/acp-20-3669-2020.

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Abstract. Gas-phase diffusion is the first step for all heterogeneous reactions under atmospheric conditions. Knowledge of binary diffusion coefficients is important for the interpretation of laboratory studies regarding heterogeneous trace gas uptake and reactions. Only for stable, nonreactive and nonpolar gases do well-established models for the estimation of diffusion coefficients from viscosity data exist. Therefore, we have used two complementary methods for the measurement of binary diffusion coefficients in the temperature range of 200 to 300 K: the arrested flow method is best suited for unstable gases, and the twin tube method is best suited for stable but adsorbing trace gases. Both methods were validated by the measurement of the diffusion coefficients of methane and ethane in helium and air as well as nitric oxide in helium. Using the arrested flow method the diffusion coefficients of ozone in air, dinitrogen pentoxide and chlorine nitrate in helium, and nitrogen were measured. The twin tube method was used for the measurement of the diffusion coefficient of nitrogen dioxide and dinitrogen tetroxide in helium and nitrogen.

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41

Gatzsche, Kathrin, Yoshiteru Iinuma, Andreas Tilgner, Anke Mutzel, Torsten Berndt, and Ralf Wolke. "Kinetic modeling studies of SOA formation from <i>α</i>-pinene ozonolysis." Atmospheric Chemistry and Physics 17, no. 21 (November 8, 2017): 13187–211. http://dx.doi.org/10.5194/acp-17-13187-2017.

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Abstract. This paper describes the implementation of a kinetic gas-particle partitioning approach used for the simulation of secondary organic aerosol (SOA) formation within the SPectral Aerosol Cloud Chemistry Interaction Model (SPACCIM). The kinetic partitioning considers the diffusion of organic compounds into aerosol particles and the subsequent chemical reactions in the particle phase. The basic kinetic partitioning approach is modified by the implementation of chemical backward reaction of the solute within the particle phase as well as a composition-dependent particle-phase bulk diffusion coefficient. The adapted gas-phase chemistry mechanism for α-pinene oxidation has been updated due to the recent findings related to the formation of highly oxidized multifunctional organic compounds (HOMs). Experimental results from a LEAK (Leipziger Aerosolkammer) chamber study for α-pinene ozonolysis were compared with the model results describing this reaction system.The performed model studies reveal that the particle-phase bulk diffusion coefficient and the particle-phase reactivity are key parameters for SOA formation. Using the same particle-phase reactivity for both cases, we find that liquid particles with higher particle-phase bulk diffusion coefficients have 310 times more organic material formed in the particle phase compared to higher viscous semi-solid particles with lower particle-phase bulk diffusion coefficients. The model results demonstrate that, even with a moderate particle-phase reactivity, about 61 % of the modeled organic mass consists of reaction products that are formed in the liquid particles. This finding emphasizes the potential role of SOA processing. Moreover, the initial organic aerosol mass concentration and the particle radius are of minor importance for the process of SOA formation in liquid particles. A sensitivity study shows that a 22-fold increase in particle size merely leads to a SOA increase of less than 10 %.Due to two additional implementations, allowing backward reactions in the particle phase and considering a composition-dependent particle-phase bulk diffusion coefficient, the potential overprediction of the SOA mass with the basic kinetic approach is reduced by about 40 %. HOMs are an important compound group in the early stage of SOA formation because they contribute up to 65 % of the total SOA mass at this stage. HOMs also induce further SOA formation by providing an absorptive medium for SVOCs (semi-volatile organic compounds). This process contributes about 27 % of the total organic mass. The model results are very similar to the LEAK chamber results. Overall, the sensitivity studies demonstrate that the particle reactivity and the particle-phase bulk diffusion require a better characterization in order to improve the current model implementations and to validate the assumptions made from the chamber simulations. The successful implementation and testing of the current kinetic gas-particle partitioning approach in a box model framework will allow further applications in a 3-D model for regional-scale process investigations.

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Zhou, Hong, Xin-Zhu Zhou, Jian Zhang, and Jian-Jun Zheng. "Effective Medium Method for Chloride Diffusion Coefficient of Mature Fly Ash Cement Paste." Materials 12, no. 5 (March 8, 2019): 811. http://dx.doi.org/10.3390/ma12050811.

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The chloride diffusion coefficient of concrete plays an essential role in the durability assessment and design of concrete structures built in chloride-laden environments. The purpose of this paper is to present an effective medium method (EMM) for evaluating the chloride diffusion coefficient of mature fly ash cement paste. In this method, a numerical method is used to estimate the degrees of hydration of cement and fly ash. Fly ash cement paste is then modeled as a two-phase composite material, composed of a solid phase and a pore space. By introducing the percolation theory, the EMM is modified to derive the chloride diffusion coefficient of fly ash cement paste in an analytical manner. To verify the EMM, a chloride diffusion test of fly ash cement paste at a curing age of up to 540 days is conducted. It is shown that, within a reasonable fly ash content, a larger fly ash content and/or curing age results in a smaller chloride diffusion coefficient. The chloride diffusion coefficient decreases with a decreasing water/binder ratio. Finally, the validity of the EMM is verified with experimental results.

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43

Brockstedt, S., C. Thomsen, R. Wirestam, J. De Poorter, C. De Wagter, L. G. Salford, S. Holtås, and F. Ståhlberg. "Use of an Enhanced Gradient System for Diffusion MR Imaging with Motion-Artifact Reduction." Acta Radiologica 36, no. 4-6 (July 1995): 662–70. http://dx.doi.org/10.1177/028418519503600471.

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Purpose: A spin-echo diffusion-sensitized pulse sequence using high gradients (23 mT/m) is introduced. Material and Methods: In order to minimize motion artefacts, velocity-compensating gradients, ECG-triggering and post-processing with phase correction and raw data averaging using navigator echoes was performed. The in vitro ratio of diffusion coefficients for water and acetone was determined and the water self-diffusion coefficient at different temperatures was evaluated. The pulse sequence was tested in 7 healthy volunteers and in 2 tumour patients with astrocytomas of grades I—II and III—IV. Both single-slice and multi-slice techniques were used. Results: The incorporation of phase correction clearly improved the quality of both diffusion-encoded images and the calculated diffusion maps. Mean values of the diffusion coefficients in vivo were for CSF 2.66×10−9 m2/s and for white and grey matter 0.69×10−9 m2/s and 0.87×10−9 m2/s, respectively. Conclusion: Velocity-compensating gradients in combination with a high gradient strength were shown to be useful for in vivo diffusion MR imaging.

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Renganathan, Sindhuja, and Ralph E. White. "Semianalytical method of solution for solid phase diffusion in lithium ion battery electrodes: Variable diffusion coefficient." Journal of Power Sources 196, no. 1 (January 2011): 442–48. http://dx.doi.org/10.1016/j.jpowsour.2010.06.081.

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45

Kumar, Rajneesh, and Vandana Gupta. "Plane wave propagation in an anisotropic dual-phase-lag thermoelastic diffusion medium." Multidiscipline Modeling in Materials and Structures 10, no. 4 (November 4, 2014): 562–92. http://dx.doi.org/10.1108/mmms-01-2014-0004.

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Purpose – The purpose of this paper is to depict the effect of thermal and diffusion phase-lags on plane waves propagating in thermoelastic diffusion medium with different material symmetry. A generalized form of mass diffusion equation is introduced instead of classical Fick's diffusion theory by using two diffusion phase-lags, one phase-lag of diffusing mass flux vector, represents the delayed time required for the diffusion of the mass flux and the other phase-lag of chemical potential, represents the delayed time required for the establishment of the potential gradient. The basic equations for the anisotropic thermoelastic diffusion medium in the context of dual-phase-lag heat transfer (DPLT) and dual-phase-lag diffusion (DPLD) models are presented. The governing equations for transversely isotropic and isotropic case are also reduced. The different characteristics of waves like phase velocity, attenuation coefficient, specific loss and penetration depth are computed numerically. Numerically computed results are depicted graphically for anisotropic, transversely isotropic and isotropic medium. The effect of diffusion and thermal phase-lags are shown on the different characteristic of waves. Some particular cases of result are also deduced from the present investigation. Design/methodology/approach – The governing equations of thermoelastic diffusion are presented using DPLT model and a new model of DPLD. Effect of phase-lags of thermal and diffusion is presented on different characteristic of waves. Findings – The effect of diffusion and thermal phase-lags on the different characteristic of waves is appreciable. Also the use of diffusion phase-lags in the equation of mass diffusion gives a more realistic model of thermoelastic diffusion media as it allows a delayed response between the relative mass flux vector and the potential gradient. Originality/value – Introduction of a new model of DPLD in the equation of mass diffusion.

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Christ, Hans Jürgen, and Peter Schmidt. "Influence of Beta Stability on Hydrogen Diffusion in Various Beta Titanium Alloys." Defect and Diffusion Forum 289-292 (April 2009): 87–94. http://dx.doi.org/10.4028/www.scientific.net/ddf.289-292.87.

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The prediction of the applicability range of beta titanium alloys in hydrogen containing environments and the systematic study of hydrogen effects on the microstructure during heat treatment require reliable information about the hydrogen diffusion coefficient DH in the respective titanium alloy. Up to now the little information available on hydrogen diffusivity in commercial titanium alloys indicates a higher hydrogen diffusion coefficient in beta titanium alloys as compared to alpha and alpha + beta titanium alloys. In the present study, the hydrogen diffusion coefficients were determined systematically by means of electrochemically charging the half length of thin titanium rods and subsequent annealing, thereby enabling hydrogen diffusion. The Matano technique was applied in order to identify any effect of hydrogen concentration on DH. The hydrogen diffusion coefficients determined were correlated with results from microstructure examination applying optical and electron microscopy. Since molybdenum and vanadium are the most important beta-stabilizing alloying elements, binary titanium alloys of the Ti–Mo and the Ti–V systems at various contents of the respective alloying element were systematically studied in addition to commerical beta titanium alloys. The results of the experiments revealed the strong effect of beta stability and phase composition on hydrogen diffusion.

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47

Miyabe, Kanji, Shigeya Takeuchi, and Yoshisato Tezuka. "Estimation of Surface Diffusion Coefficient in Reversed-Phase Liquid Chromatography Using Methanol/Water Mobile Phases." JOURNAL OF CHEMICAL ENGINEERING OF JAPAN 31, no. 3 (1998): 347–54. http://dx.doi.org/10.1252/jcej.31.347.

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48

Torres, Juan F., Atsuki Komiya, Junnosuke Okajima, and Shigenao Maruyama. "Measurement of the Molecular Mass Dependence of the Mass Diffusion Coefficient in Protein Aqueous Solutions." Defect and Diffusion Forum 326-328 (April 2012): 452–58. http://dx.doi.org/10.4028/www.scientific.net/ddf.326-328.452.

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This paper reports the measurement of the binary mass diffusion coefficient for proteins with a wide range of molecular size. The diffusion coefficient is obtained by conducting diffusion experiments in the dilute region. Transient concentration profiles were measured by a phase shifting interferometer and subsequently compared with a numerical calculation based on Ficks law to determine the diffusion coefficient. Distilled water was used as solvent in free diffusion experiments conducted at T = (25 ± 1.0)°C. The method was validated by measuring the diffusion coefficient of aqueous NaCl, Sucrose, and BSA, which values have been extensively reported in the literature. The values of the diffusion coefficient for seven proteins: aprotinin (6.5 kDa), α-lactalbumin (14.2 kDa), lysozyme (14.3 kDa), trypsin inhibitor (20.1 kDa), ovalbumin (44.2 kDa), bovine serum albumin (66.7 kDa), and phosphorylase b (97.2 kDa), were determined in the dilute region of 0-3 mg/ml. The results are compared with the Stokes-Einstein equation. The influence of the molecular structure and pH on the diffusion coefficient is discussed.

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IKUMA, Yasuro, and Yoshihide TSUBAKI. "Oxygen Isotope Exchange Reaction in Diffusion Coefficient Measurements Using Gas Phase Analysis." Journal of the Ceramic Society of Japan 104, no. 1207 (1996): 232–34. http://dx.doi.org/10.2109/jcersj.104.232.

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50

Wang Zhen-Zhong, Wang Nan, and Yao Wen-Jing. "Effect of low diffusion coefficient on glass phase formation in Pd77Cu6Si17 alloy." Acta Physica Sinica 59, no. 10 (2010): 7431. http://dx.doi.org/10.7498/aps.59.7431.

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Journal articles on the topic 'Phase diffusion coefficient'

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