Showing papers on "Critical radius published in 2014"
TL;DR: In this paper, the electrophoretic mobility of a salt-free system was studied as a function of the colloid volume fraction, the particle radius, and the bare charge density.
Abstract: A highly-charged spherical colloid in a salt-free environment exerts such a powerful attraction on its counterions that a certain fraction condenses onto the surface of a particle. The degree of condensation depends on the curvature of the surface. So, for instance, condensation is triggered on a highly-charged sphere only if the radius exceeds a certain critical radius R*. R* is expected to be a simple function of the volume fraction of particles. To test these predictions, we prepare spherical particles which contain a covalently-bound ionic liquid, which is engineered to dissociate efficiently in a low-dielectric medium. By varying the proportion of ionic liquid to monomer we synthesise nonpolar dispersions of highly-charged spheres which contain essentially no free co-ions. The only ions in the system are counterions generated by the dissociation of surface-bound groups. We study the electrophoretic mobility of this salt-free system as a function of the colloid volume fraction, the particle radius, and the bare charge density and find evidence for extensive counterion condensation. At low electric fields, we observe excellent agreement with Poisson–Boltzmann predictions for counterion condensation on spheres. At high electric fields however, where ion advection is dominant, the electrophoretic mobility is enhanced significantly which we attribute to hydrodynamic stripping of the condensed layer of counterions from the surface of the particle.
43 citations
TL;DR: In this paper, a second order accurate finite-volume compressible flow solver is employed to assess the effectiveness of leading edge bluntness in reducing the separation bubble size, which is attributed mainly to the existence of a wide over pressure region.
35 citations
TL;DR: In this article, the solubility curves of Er and Yb in Al at high temperature were evaluated from the electrical resistivity measurement, from which the Δ S and Δ H were estimated to be 3.0,± 0.1k and −0.86, ± 0.10%, respectively, which were obviously less than that of Al 3 Sc, i.e., 0.92%.
35 citations
TL;DR: The CFD model is developed to obtain numerical solutions of Stokes equations in three dimensions, validated with experiments reported in literature, and used to analyze the effects of geometric parameters, such as the helical radius, wavelength, radii of the channel and the Tail and the tail length on forward and lateral swimming velocities, rotation rates, and the efficiency of the swimmer.
35 citations
TL;DR: A single-fluid two-phase model and a LBE model for nonideal gases are used and it is found that the method indeed produces a density shift, bubble or droplet shrinkage, as well as a critical radius below which the bubble orDroplet eventually vanishes.
Abstract: One characteristic of multiphase lattice Boltzmann equation (LBE) methods is that the interfacial region has a finite (i.e., noninfinitesimal) thickness known as a diffuse interface. In simulations of, e.g., bubble or drop dynamics, for problems involving nonideal gases, one frequently observes that the diffuse interface method produces a spontaneous, nonphysical shrinkage of the bubble or drop radius. In this paper, we analyze in detail a single-fluid two-phase model and use a LBE model for nonideal gases in order to explain this fundamental problem. For simplicity, we only investigate the static bubble or droplet problem. We find that the method indeed produces a density shift, bubble or droplet shrinkage, as well as a critical radius below which the bubble or droplet eventually vanishes. Assuming that the ratio between the interface thickness $D$ and the initial bubble or droplet radius ${r}_{0}$ is small, we analytically show the existence of this density shift, bubble or droplet radius shrinkage, and critical bubble or droplet survival radius. Numerical results confirm our analysis. We also consider droplets on a solid surface with different curvatures, contact angles, and initial droplet volumes. Numerical results show that the curvature, contact angle, and the initial droplet volume have an effect on this spontaneous shrinkage process, consistent with the survival criterion.
33 citations
TL;DR: In this article, single crystals of brucinium 2-carboxy-6-nitrophthalate dihydrate (B2C6ND) have been grown by the slow evaporation solution technique at room temperature using water-ethanol (1:1) mixed solvent.
30 citations
TL;DR: The energy landscape of the protonic defect in acceptor-doped barium stannate using density-functional calculations is investigated in this article, where several trivalent dopants are studied (Ga, Sc, In, Y, Gd, La), covering a wide range of ionic radii.
Abstract: The energy landscape of the protonic defect is investigated in acceptor-doped barium stannate using density-functional calculations. Several trivalent dopants are studied (Ga, Sc, In, Y, Gd, La), covering a wide range of ionic radii. All the dopants are found attractive with respect to the proton, with (negative) association energies varying from −0.40 to −0.07 eV. A radius rc1 is defined to separate the “small” dopants that induce tensile stress from the “large” ones that induce compressive stress in the host matrix (rc1 ≈ 0.72 A). The protonic energy surface exhibits a non-trivial evolution with ionic radius of the dopant: for low dopant radii, the most stable protonic site is the oxygen first-neighbor of the dopant, while for high dopant radii, the most stable position is obtained when the proton is bonded to an oxygen second-neighbor of the dopant. This evolution of the protonic energy surface with dopant ionic radius is smooth and the transition takes place between In and Y, i.e. for a critical radius rc2 between 0.80 and 0.90 A (rc2 > rc1 significantly). The dopant–proton association energy exhibits a minimal value ≈−0.07 eV (weakest attraction) at this transition, i.e. in the case of yttrium, for which the first-neighbor and second-neighbor positions are almost degenerate. Other dopants, smaller or larger, are more attractive to protons. The present study gives useful information about the modification of the trapping effect according to the dopant ionic size.
25 citations
TL;DR: In this paper, the authors derived the minimum power of jets and their magnetic field strength based on their observed non-thermal synchrotron emission and showed that the minimum jet power is independent of its radius when the ion rest mass power dominates, which becomes the case below certain critical radius.
Abstract: We derive the minimum power of jets and their magnetic field strength based on their observed non-thermal synchrotron emission. The correct form of this method takes into account both the internal energy in the jet and the ion rest-mass energy associated with the bulk motion. The latter was neglected in a number of papers, which instead adopted the well-known energy-content minimization method. That method was developed for static sources, for which there is no bulk-motion component of the energy. In the case of electron power-law spectra with index >2 in ion-electron jets, the rest-mass component dominates. The minimization method for the jet power taking it into account was considered in some other work, but only based on either an assumption of a constant total synchrotron flux or a fixed range of the Lorentz factors. Instead, we base our method on an observed optically-thin synchrotron spectrum. We find the minimum jet power is independent of its radius when the ion rest-mass power dominates, which becomes the case below certain critical radius. This allows for robust minimum power estimates. We also present results for the case with observed turnover frequency, at which the source becomes optically thick. This method allows a determination of the source size, in addition to the power and the magnetic field. We also point out that when the ion rest-mass power dominates, the estimates of the minimum power lead to very different equipartition parameters than those based on minimization of the energy content. The former and latter lead to approximate equipartition between the internal energy in magnetic field and in particles including and excluding, respectively, their rest mass energy.
24 citations
TL;DR: In this article, the effect of the selective additive sodium nitrate on the nucleation behavior of the α and γ polymorphs of glycine is investigated both by experimental and analytical approaches.
Abstract: Nucleation of either the α or γ polymorph of glycine takes place by the dominant existence of dimer or monomer molecular conformations in solution. The effect of the selective additive sodium nitrate on the nucleation behaviour of the α and γ polymorphs of glycine is investigated both by experimental and analytical approaches. Experimentally, in situ nucleation tests were performed to measure the induction period of nucleation, type of nucleation and their proportionate appearance in the presence of different concentrations of the additive in solution. The internal structure of the nucleated crystallites was confirmed by single crystal X-ray diffraction analysis. Nucleation of α and γ glycine takes place through a charge compensation mechanism. The incorporation of various concentrations of the additive changes the supersaturation of the system, which in turn changes the induction period of nucleation. Nucleation of the γ polymorph occurs at a critical concentration of the additive. Analytically, the nucleation parameters, such as interfacial energy, volume excess free energy, critical radius, critical energy barrier and nucleation rate of the α and γ polymorphs, were estimated based on classical nucleation theory from the experimentally measured induction periods. Variation in these theoretically deduced nucleation parameters with respect to the supersaturation in the system coincides well with the experimentally observed variation of these parameters during the kinetic processes observed within the experimental conditions. This correlation between the experimental and theoretical evidences provides a deeper insight in enabling us to have a clear idea as to what exactly happens inside the system. Moreover, the probability nucleation ratio of the α and γ polymorphs, estimated by powder X-ray diffraction and DSC followed by their structural confirmations, coincides very well with the experimentally observed values.
23 citations
TL;DR: In this paper, the authors compare the properties of populations in which the critical radius is chosen to be the pre-CE core radius or the post-CE stripped remnant radius, and find the types of systems for which these changes are most important.
Abstract: Many classes of objects and events are thought to form in binary star systems after a phase in which a core and companion spiral to smaller separation inside a common envelope (CE).Such a phase can end with the merging of the two stars or with the ejection of the envelope to leave a surviving binary system.The outcome is usually predicted by calculating the separation to which the stars must spiral to eject the envelope, assuming that the ratio of the core--envelope binding energy to the change in orbital energy is equal to a constant efficiency factor $\alpha$. If either object would overfill its Roche lobe at this end-of-CE separation, then the stars are assumed to merge. It is unclear what critical radius should be compared to the end-of-CE Roche lobe for stars which have developed cores before the start of a CE phase. After improving the core radius formulae in the widely used BSE rapid evolution code, we compare the properties of populations in which the critical radius is chosen to be the pre-CE core radius or the post-CE stripped remnant radius. Our improvements to the core radius formulae and the uncertainty in the critical radius significantly affect the rates of merging in CE phases of most types. We find the types of systems for which these changes are most important.
21 citations
TL;DR: In this article, a new parameter combining rpIc with rpIIc has been proposed, and accordingly, the preexisting R-criterion has been improved.
Abstract: For elastic-plastic materials, the plastic core region around a crack tip generally has a limited dimension, and therefore, the corresponding radius rp from the crack tip to the elastic-plastic boundary can be considered as a critical parameter. However, neither the critical radius rpIc for mode I nor the critical radius rpIIc for mode II can be applied solely as the critical parameter to predict mixed-mode fractures well. In current work, a new parameter combining rpIc with rpIIc has been proposed, and accordingly, the preexisting R-criterion has been improved. The improved R-criterion not only can predict crack initiation angle but also can predict the critical load, which is more significant in predicting material fractures. A series of fracture tests using the semicircular bend specimens with different mode mixities were conducted on polycarbonate (PCBA), and the test results were compared with the predictions of several criteria. This comparison shows that the test results agree well with the...
TL;DR: It is shown that the growth of the two-cluster phase from the metastable ordinary fluid is extremely slow, even for large supersaturations, and the apparent paradox of the observation of an activation barrier to nucleation in a system where, due to the dimensionality of the hosting space, the critical radius is expected to vanish is clarified.
Abstract: Phase transitions are uncommon among homogeneous one-dimensional fluids of classical particles owing to a general nonexistence result due to van Hove A way to circumvent van Hove's theorem is to consider an interparticle potential that is finite everywhere Of this type is the generalized exponential model of index 4 (GEM4 potential), a model interaction which in three dimensions provides an accurate description of the effective pair repulsion between dissolved soft macromolecules (eg, flexible dendrimers) Using specialized free-energy methods, I reconstruct the equilibrium phase diagram of the one-dimensional GEM4 system, showing that, apart from the usual fluid phase at low densities, it consists of an endless sequence of cluster fluid phases of increasing pressure, having a sharp crystal appearance for low temperatures The coexistence line between successive phases in the sequence invariably terminates at a critical point Focussing on the first of such transitions, I show that the growth of the two-cluster phase from the metastable ordinary fluid is extremely slow, even for large supersaturations Finally, I clarify the apparent paradox of the observation of an activation barrier to nucleation in a system where, due to the dimensionality of the hosting space, the critical radius is expected to vanish
TL;DR: This work uses non-equilibrium molecular dynamics simulations to study the heat transfer around intensely heated solid nanoparticles immersed in a model Lennard-Jones fluid and explains the stability in terms of the Laplace pressure associated with the formation of a vapor nanocavity and the associated effect on the Gibbs free energy.
Abstract: We use non-equilibrium molecular dynamics simulations to study the heat transfer around intensely heated solid nanoparticles immersed in a model Lennard-Jones fluid. We focus our studies on the role of the nanoparticle curvature on the liquid phase stability under steady-state heating. For small nanoparticles we observe a stable liquid phase near the nanoparticle surface, which can be at a temperature well above the boiling point. Furthermore, for particles with radius smaller than a critical radius of 2 nm we do not observe formation of vapor even above the critical temperature. Instead, we report the existence of a stable fluid region with a density much larger than that of the vapor phase. We explain the stability in terms of the Laplace pressure associated with the formation of a vapor nanocavity and the associated effect on the Gibbs free energy.
TL;DR: In this article, the effect of linear shear flow on particle growth in the undercooled melt by using the method of matched asymptotic expansion was studied, and the analytical result showed that the shear effect of flow results in the significant distorted deformation of the interface.
TL;DR: Transport of particles with different sizes moving in a two-dimensional periodic channel is studied in the presence of an unbiased external force and a periodic energetic potential to contribute further to the invention of machines for particle separation.
Abstract: Transport of particles with different sizes moving in a two-dimensional periodic channel is studied in the presence of an unbiased external force and a periodic energetic potential. While particles are going through entropic barrier resulting from the geometric restraints, the transport is also influenced by the energetic potential. For the case of an unbiased external force, the competition between the energetic potential and entropic barrier leads to different transport direction of particles, which sensitively depends on the particles radius. Particles move to the left when smaller than a critical radius and larger than another critical radius, whereas particles move to the right in the range of two critical radii. Therefore, the results we have presented can contribute further to the invention of machines for particle separation.
TL;DR: In this article, the authors compared theoretical computations of the critical radii of the transition of partial dislocation loops to full ones with allowance for the dislocation loop formation energy and stacking fault energy of the materials.
Abstract: The dislocation loop size distribution in semiconductors CdTe, ZnTe, ZnSe, ZnS, CdS, GaAs, Si, and Ge has been studied using transmission electron microscopy. The experimental results have been compared with theoretical computations of the critical radii of the transition of partial dislocation loops to full ones with allowance for the dislocation loop formation energy and stacking fault energy of the materials. It has been shown that the critical radius depends on the stacking fault energy and is an important characteristic in the analysis of the defect formation processes in semiconductors.
01 Jan 2014
TL;DR: In this paper, an investigation of various heat transfer parameters like thermal conductivity, Convective heat transfer coefficient, length of cylinder on the effect of crossover radius of cylindrical insulating system is carried out using a computer code developed on ‘C’ platform.
Abstract: Insulating the radial thermal system is based on the concept of critical radius which is widely discussed in the literature. When it is required to increase heat dissipation as in electrical transmission, critical radius can be used for maximum heat dissipation. But if it is desirable to decrease heat dissipation, critical radius alone cannot be sufficient. For such systems, the concept of crossover radius has to be used and is defined as the radius greater than the critical radius such that the heat transfer with the corresponding amount of insulating material is equal to that of the bare thermal system. In this paper an investigation of various heat transfer parameters like thermal conductivity, Convective heat transfer coefficient ,length of cylinder on the effect of crossover radius of cylindrical insulating system is carried out using a computer code developed on ‘C’ platform. The code is validated by comparing critical radius profiles for thermal insulating system with those reported in literature. From the obtained results, novel conclusion for the design of radial thermal insulating systems (Cylinder) can be drawn.
TL;DR: It is pointed out that the diffusional equation may lead to a kinetic critical radius that is different from the thermodynamic critical radius, thus indicating the possibility of kinetically controlling the critical radius of a nucleus.
Abstract: The critical radius of a nucleus grown by diffusion in a solution is studied thermodynamically as well as kinetically. The thermodynamic growth equation called Zeldovich equation of classical nucleation theory and the kinetic diffusional growth equation combined with the Ostwald-Freundlich boundary condition lead to the same critical radius. However, it should be pointed out that the diffusional equation may lead to a kinetic critical radius that is different from the thermodynamic critical radius, thus indicating the possibility of kinetically controlling the critical radius of a nucleus.
TL;DR: In this article, a fine-grained microstructure was obtained under a certain crucible nucleation undercooling and related mechanisms are discussed, where the solidification process of the undercooled melt is divided into two parts, a nonequilibrium process and a near-equilibrium process.
TL;DR: In this article, the adequacy of the model of high-temperature precipitation in dislocation-free silicon single crystals to the classical theory of nucleation and growth of second-phase particles in solids has been considered.
Abstract: The adequacy of the model of high-temperature precipitation in dislocation-free silicon single crystals to the classical theory of nucleation and growth of second-phase particles in solids has been considered. It has been shown that the introduction and consideration of thermal conditions of crystal growth in the initial equations of the classical nucleation theory make it possible to explain the precipitation processes occurring in the high-temperature range and thus extend the theoretical basis of the application of the classical nucleation theory. According to the model of high-temperature precipitation, the smallest critical radius of oxygen and carbon precipitates is observed in the vicinity of the crystallization front. Cooling of the crystal is accompanied by the growth and coalescence of precipitates. During heat treatments, the nucleation of precipitates starts at low temperatures, whereas the growth and coalescence of precipitates occur with an increase in the temperature. It has been assumed that the high-temperature precipitation of impurities can determine the overall kinetics of defect formation in other dislocation-free single crystals of semiconductors and metals.
TL;DR: There is an optimal pressure in the solvation free energy, as a result of the competition between the creation of nanoparticle-fluid interface and the formation of cavity volume, in the temperature range where there is triple-phase coexistence.
Abstract: We study the solvation of a single nanoparticle in poly(methyl methacrylate)–CO_2 mixture at coexistence by using statistical classical density-functional theory. In the temperature range where there is triple-phase coexistence, the lowest solvation free energy occurs at the triple point pressure. Beyond the end point temperature of the triple line, and for particle radii less than a critical value, there is an optimal pressure in the solvation free energy, as a result of the competition between the creation of nanoparticle–fluid interface and the formation of cavity volume. The optimal pressure decreases with increasing nanoparticle radius or the strength of nanoparticle attraction with the fluid components. The critical radius can be estimated from the pressure dependence of the interfacial tension between the fluid and the particle in the limit of infinitely large particle size (i.e., planar wall).
TL;DR: In this article, a self-assembly VHF-PECVD method was used to grow nanocrystalline silicon (nc-Si) nanodots on corning glass (7059) substrate.
Abstract: Nanocrystalline silicon (nc-Si) nanodots have been grown on corning glass (7059) substrate using a self-assembly VHF-PECVD method under the following experimental conditions: Fixed deposition temperatures of 300/400 °C, deposition times 30/60 s, plasma power of 10 W, silane gas flow rate of 10 sccm, as well as deposition pressure of 10-2 torr. It is predicted that the onset of nucleation began immediately after the deposition and start to appear clearly after 20-60 s during which growth mechanisms occur. Essentially, the nanodots were formed onto the substrate in dome-like shapes by virtue of equilibrium surface energies, γLS, γLN andγNS. The associated liquid/solid nucleation mechanism was then simulated and related parameters were obtained: Free energy change per unit volume ΔGv ∼-104 Jmol-1; Surface energies per unit area, γLN = 1.44 Jm-2, γNS = 19 - 60 Jm-2 and γLS = 0.74 Jm-2; Critical energies ΔG* ∼10-15 J; Critical radii r* = 16 - 48 nm. These results were experimentally verified, in particular for selected critical radius r* less than 50 nm.Other measurements were also carried out: PL analysis gave bandgap energies ∼ 1.8-2.4 eV, whilst Raman spectra revealed the coexistence of nc-Si and amorphous Si. It is strongly suggested that, the nc-Si nanodot grown on glass substrate fulfills the Volmer-Weber growth mode with a minor modification.
Posted Content•
TL;DR: In this article, the authors consider a class of weighted volume preserving curvature flows acting on hypersurfaces that are trapped within two parallel hyperplanes and satisfy an orthogonal boundary condition.
Abstract: In this paper we consider a class of weighted-volume preserving curvature flows acting on hypersurfaces that are trapped within two parallel hyperplanes and satisfy an orthogonal boundary condition. In the author's thesis the stability of cylinders under the flows was considered; it was found that they are stable provided the radius satisfies a certain condition. Here we consider flows where there is a critical radius such that the cylinders are only stable on one side of the critical value, and the weight function is a linear combination of the elementary symmetric functions, the reason for such a choice is made clear in the appendix. We find that in such instances bifurcation from the cylindrical stationary solutions occurs at the critical radius and we determine a condition on the speed and weight functions such that the nearby non-cylindrical stationary solutions are stable under the flow. We will also highlight the specific cases of homogeneous speed functions and the mixed-volume preserving mean curvature flows.
22 Dec 2014
TL;DR: In this article, the minimum air clearance required for a ±1100 kV HVDC converter valve installation was calculated by using the previous studies of Ball-plate electrodes critical radius.
Abstract: ±1100 kV is the highest UHVDC voltage level in the world. ±1100 kV HVDC converter valve is a core equipment, and therefore determining the minimum indoor air clearance for its external insulation is significant. In this paper, according to switching impulse withstand level (SIWL) of ±1100 kV HVDC converter valve, minimum air clearance required for a ±1100 kV HVDC converter valve installation were calculated. In order to improve the SIWL and shorten the minimum air clearance, the stress shield assembly of A5000 series ±1100 kV HVDC converter valve installation was designed by using the previous studies of Ball-plate electrodes critical radius. In the end, a C-EPRI A5000 type ±1100 kV UHVDC converter valve was used to carry out switching impulse tests at the SGCC UHVDC test base in Beijing. The results shows that the new design of the stress shield assembly can effectively shorten air clearance.
TL;DR: In this article, the nucleation rate of two microalloyed steels with V and Nb at a strain of 0.35 and a strain rate of 3.63 s-1.1 s, respectively, was calculated using the classic theory of nucleation.
Abstract: Recrystallization-precipitation-time-temperature (RPTT) diagrams were experimentally determined for two microalloyed steels with V and Nb, respectively, at a strain of 0.35 and a strain rate of 3.63 s-1. From the RPTT diagrams, and applying the classic theory of nucleation, the nucleation rate was calculated for both steels. In order to determine the mentioned magnitudes, several parameters were calculated, such as: the Zeldovich factor (Z), the energy of formation of the nucleus (ΔG), the driving force for precipitation (ΔGv), the critical radius for nucleation (Rc), and the dislocation density at the start of precipitation (ρ), among others. The calculated data has made it possible to clarify the shape of precipitation start and finish curves and to plot the nucleation rate as a function of temperature. The number of precipitates was calculated by integration of the nucleation rate expression. In this way, substantial differences were established between the two types of microalloyed steels, including the final size of the V(C, N) and Nb (C, N) precipitates.
TL;DR: In this article, the linear stability of a single component axi-symmetrical solid in contact with its melt is theoretically investigated with respect to the development of longitudinal sinusoidal fluctuations of wavelengths λ 2 π R e, with Re its radius, in the solidification and melting regime.
TL;DR: In this paper, the solubility of a BAP sample in double distilled water was determined at different temperatures by employing the polythermal method and solution stability was studied by observing the metastable zone width by employing a polythermometer.
Abstract: Beta-alaninium picrate (BAP) salt has been synthesized and the solubility of the synthesized sample in double distilled water was determined at different temperatures. Solution stability was studied by observing the metastable zone width by employing the polythermal method. Induction period values for different supersaturation ratios at room temperature were determined based on the isothermal method. The nucleation parameters such as critical radius, critical free energy change, interfacial tension, and nucleation rate have been estimated for BAP salt on the basis of the classical nucleation theory. The lattice parameters of the grown BAP crystal were determined using the x-ray diffraction (XRD) technique. The reflection planes of the sample were confirmed by the powder XRD study and diffraction peaks were indexed. Fourier transform infrared spectroscopy and Fourier transform–Raman studies were used to confirm the presence of various functional groups in the BAP crystal. The nonlinear optical property of the grown crystal was studied using the Kurtz–Perry powder technique. UV–visible spectral studies were carried out to understand optical transparency and the type of band gap of the grown BAP crystal.
Journal Article•
TL;DR: In this paper, the optimal construct of a branched-pattern disc with optimal global heat conduction performance is obtained based on constructal theory, and the optimal construction based on minimum entransy dissipation rate can reduce the average heat transfer temperature difference.
Abstract: Based on constructal theory,the constructal optimization of a branched-pattern disc at micro and nanoscales is carried out by taking minimum entransy dissipation rate as optimization objective,and the optimal construct of the branched-pattern disc with optimal global heat conduction performance is obtained.The result shows that the optimal construct of the branched-pattern disc when the size effect takes effect is obviously different from that when the size effect does not take effect.There exists an optimal elemental fraction of the high conductivity material which leads to the minimum dimensionless average temperature difference of the branched-pattern disc.For the structure forms nn,nb and bb of the branched-pattern disc,the critical dimensionless radiuses are 1.16,1.45 and 1.75,respectively.When the radius of the branched-pattern disc is large than the critical radius,branched-pattern design of the high conductivity material in the disc should be adopted,otherwise the radial-pattern design should be adopted.The optimal construct based on minimum entransy dissipation rate can reduce the average heat transfer temperature difference of the disc,and improves its global heat transfer performance.
01 Aug 2014
TL;DR: In this paper, the dependence of the induction period of crystalli zation on super cooling was determined for the syst em lithium chloride-potassium acid phthalate (KAP) over the co mposition of 1mole % LiCl2.
Abstract: The dependence of the induction period of crystalli zation on super cooling was determined for the syst em lithium chloride—potassium acid phthalate (KAP) over the co mposition of 1mole % LiCl2. This dependence can be described by 1/ ( lnS) 2 against ln τ curve. In order to reduce the effect of heterogene ous nucleation on the nucleation parameters, the interfacial energy was c alculated from the slopes determined in the linear region of the line plots. Nucleation parameters like free energy change, rate of nucleation and critical radius were determined using the value of interfacial energy. Correction was made to the interfacial energy based on the thermodynamically approach. An attempt has been mad e to calculate the nucleation parameters correspond ing to the critical super saturation ratio using the modif ied classical nucleation theory.