Determination of binary mixture vapor-liquid critical densities from coexisting density data

In the evolving universe, cosmic thermal energy density is always directly proportional to the critical mass-energy density. At any time, the product of cosmic ‘critical density’ and ‘critical Hubble volume’ can be called as the ‘critical mass’ of the evolving universe. With reference to Mach’s principle, cosmic ‘critical density’, ‘critical volume’ and ‘critical mass’ can be considered as the quantified back ground dynamic properties of the evolving universe. With reference to Planck mass, Hubble constant connected with big bang and critical density connected with big bang- both can be defined. With ‘cosmologically reinforcing hydrogen atom’ concept, observed cosmic redshift and super novae dimming both can be reinterpreted in a new approach. To understand the ground reality of cosmic rate of expansion, accuracy of the current methods of estimating the magnitudes of current Hubble’s constant and current CMBR temperature must be improved.

Critical densities from coexisting density data: application to refrigerants R22, R134a, and R124

The solvent around protein molecules in solutions is structured and this structuring introduces a repulsion in the intermolecular interaction potential at intermediate separations. We use Monte Carlo simulations with isotropic, pair-additive systems interacting with such potentials. We test if the liquid-liquid and liquid-solid phase lines in model protein solutions can be predicted from universal curves and a pair of experimentally determined parameters, as done for atomic and colloid materials using several laws of corresponding states. As predictors, we test three properties at the critical point for liquid-liquid separation: temperature, as in the original van der Waals law, the second virial coefficient, and a modified second virial coefficient, all paired with the critical volume fraction. We find that the van der Waals law is best obeyed and appears more general than its original formulation: A single universal curve describes all tested nonconformal isotropic pair-additive systems. Published experimental data for the liquid-liquid equilibrium for several proteins at various conditions follow a single van der Waals curve. For the solid-liquid equilibrium, we find that no single system property serves as its predictor. We go beyond corresponding-states correlations and put forth semiempirical laws, which allow prediction of the critical temperature and volume fraction solely based on the range of attraction of the intermolecular interaction potential.

The paper is concerned with the nucleation, growth and coalescence of microdefects in the form of voids in S235JR steel. The material is known to be one of the basic steel grades commonly used in the construction industry. The theory and methods of damage mechanics were applied to determine and describe the failure mechanisms that occur when the material undergoes deformation. Until now, engineers have generally employed the Gurson-Tvergaard- Needleman model. This material model based on damage mechanics is well suited to define and analyze failure processes taking place in the microstructure of S235JR steel. It is particularly important to determine the critical void volume fraction fc, which is one of the basic parameters of the Gurson-Tvergaard-Needleman material model. As the critical void volume fraction fc refers to the failure stage, it is determined from the data collected for the void coalescence phase. A case of multi-axial stresses is considered taking into account the effects of spatial stress state. In this study, the parameter of stress triaxiality η was used to describe the failure phenomena. Cylindrical tensile specimens with a circumferential notch were analysed to obtain low values of initial stress triaxiality (η = 0.556 of the range) in order to determine the critical void volume fraction fc. It is essential to emphasize how unique the method applied is and how different it is from the other more common methods involving parameter calibration, i.e. curve-fitting methods. The critical void volume fraction fc at void coalescence was established through digital image analysis of surfaces of S235JR steel, which involved studying real, physical results obtained directly from the material tested.

Planar drop-sizing and liquid volume fraction measurements of airblast spray in cross-flow using SLIPI-based techniques

Ebulliometric determination and prediction of (vapor + liquid) equilibria for binary and ternary mixtures containing alcohols (C 1–C 4) and dimethyl carbonate

Measurements of the storage modulus of suspensions of marble particles in a surfactant-based lyotropic liquid-crystalline medium (lamellar, smectic B) are reported. The suspension is a model system for several food and consumer products. The storage modulus is found to remain nearly constant with an increase in the particle volume fraction until a critical value is reached, beyond which a sharp increase in the storage modulus is obtained. The critical volume fraction is found to increase with an increase in particle size. The storage modulus of the suspensions exhibits a power law dependence on the oscillation frequency, and the power law exponent decreases sharply near the critical volume fraction. The experimental data indicate a transition from a multidomain lamellar liquid-crystalline structure to a structure with a rigid sample spanning network. A network model for the suspension is proposed in which a large number of parallel lamellae bridge randomly placed particles with surfaces closer than a specified distance, the maximum layer size (sm). The network formation is essentially a continuum percolation problem, for which the dimensionless critical number density is found by numerical simulations to be alpha(c) = rho(c)(1/3)L(m) approximate to 0.87 where L-m is the maximum distance between the centers of bonded particles and rho(c) is the critical number density. The modulus (G(c)) of the percolation network is obtained computationally as the stress required for a small tensile deformation of the network. The computed modulus is found to be of the form G(c) proportional to rho(2/3)(alpha - alpha(c))(2.5), which is in good agreement with experimental data.

The mechanisms controlling normal and exaggerated grain growth in lead magnesium niobate–lead titanate (PMN–PT) ceramics have been investigated by varying the PbO‐based liquid‐phase volume fraction from 0.03 to 0.6 and sintering temperature from 900° to 1100°C. There is a transition in matrix grain growth rate and matrix grain shape with liquid fraction; samples with liquid volume fractions less than ∼0.15 show relatively small equiaxed grains resulting from grain‐to‐grain impingement. Samples with higher liquid fractions show significantly larger, facetted, cube‐shaped grains, whose size is independent of liquid fraction, indicating that a surface nucleation rate mechanism controls growth in this regime. Exaggerated grains were found in the high liquid fraction samples. Electron backscatter diffraction showed that all of the exaggerated grains contained 60°〈111〉 twins but none of the normal matrix grains contained twins. The reentrant angles in the twinned grains give them a growth advantage over untwinned grains, resulting in a population of exaggerated grains.

The characterization and interpretation of ductile fracture mechanisms in AL2024-T351 using X-ray and focused ion beam tomography

Experimental determination and theoretical modeling of isobaric vapor–liquid equilibria, liquid mass density, surface tension and dynamic viscosity for the methyl butyrate and tert-butanol binary mixture

The thermodynamic analysis of the coexistence curves with any number of critical points in binary mixtures at constant pressure was carried out in the framework of the regular-mixing theory. We proposed a universal temperature dependence of the general energy interaction parameter both for one and for several critical points. An evolution of multicritical point coexistence curves was analyzed and a unified consideration of the boundaries of liquid-liquid and vapor-liquid equilibria was fulfilled. As a result, new properties of the multicritical point coexistence curves were derived and new phase transitions were theoretically predicted. The relationships between conjugate phase separation temperatures were applied to calculate a pressure dependence of mutual solubility of the 2-butanol/water mixtures as a system with three critical points. Moreover, the generalized reduced temperature for the systems with several critical points was introduced to compare scaling and regular-mixing approaches to the quantitative description of the published experimental data on coexistence curves with two critical points.

In this paper, presented is an experimental study of thermal flow-induced vibration in a both-ends-closed type self-induced oscillating heat pipe. This was made of winding glass tube to visualize the phenomenon. It was heated at the bottom to control temperature by heater, while was cooled at the top to keep temperature constant. Liquid column oscillation was excited with boiling and expansion of vapor plug. When liquid volume fraction was large, the magnitude of pressure oscillation was large and low frequency was relatively dominant. Furthermore, normalized temperature θt was proposed to investigate the threshold of excited conditions, taking account of initial condition, e.g. initial pressure. With respect to liquid volume fraction, θt was alternately varied up and down. This phenomenon was evaluated to be dependent on the liquid volume fraction.

The velocity fields measured by experiments or determined through simulations are essential in advancing our understanding of the complex atomization process of impinging jets. However, existing methods are expensive and time-consuming. In this study, we apply deep learning to the estimation of the three-dimensional velocity fields produced by the atomization of two impinging jets. Two deep learning models are developed, namely, a liquid volume fraction (LVF) estimation model based on the Swin Transformer architecture and a three-dimensional velocity field estimation model based on four-dimensional convolution (4D-Conv). The dataset for training the models is generated by direct numerical simulations (DNS). To train the LVF model, we utilize two gray images generated by a pinhole camera model, mimicking the acquisition of experimental images. We then introduce a mask generated by binocular vision techniques into the LVF model. The LVF fields estimated with the mask are in better agreement with the reference DNS data. We further utilize the estimated LVF fields to train the 4D-Conv-based model. The mean absolute percentage error compared with the results of a full-flow test is found to be less than 5%. The results indicate that the proposed approach has the potential to accurately reconstruct volume velocity data from two-dimensional images.

Conductivity behavior of the fresh CA mortar and its relationship with the fluidity properties

Critical properties and vapor-liquid equilibrium of two near-azeotropic mixtures containing HFOs