Formation of Natural Egg Yolk Granule Stabilized Pickering High Internal Phase Emulsions by Means of NaCl Ionic Strength and pH Change

Pickering high internal phase emulsions (HIPEs) are gel-like concentrated emulsions that have the potential to be an alternative to partially hydrogenated oil (PHO). In this study, egg yolk granules (EYGs), natural complexes of protein and lipid isolated from egg yolk, were used as an emulsifier to prepare Pickering HIPEs. Gel-like HIPEs with an oil phase volume fraction of 85% and with an emulsifier concentration of only 0.5% could be prepared by using EYGs as an emulsifier. The EYGs were able to form stable HIPEs at NaCl ionic strengths over 0.2 M and at pH over 5.0 with NaCl ionic strength of 0.3 M. The EYGs, which could stabilize HIPEs, were easily to adsorb and cover the oil-water interface to form emulsion droplets with small particle size. In addition, interacting EYGs in the aqueous phase formed a continuous network structure, and the oil droplets packed closely, exhibiting high elasticity and shear thinning behavior. Furthermore, the formed HIPEs had suitable storage stability with no significant changes in appearance and microstructure after storage for 60 days. This work can transform traditional oils from liquid-like to solid-like by using EYGs to enrich food processing diversity and improve the storage stability of oils while reducing the intake of PHO and providing a healthier diet for consumers.

Cavitation of Multiscale Vortices in Circular Cylinder Wake at Re = 9500

Cavitation characteristics in the wake of a circular cylinder, which contains multiscale vortices, are numerically investigated via Large Eddy Simulation (LES) in this paper. The Reynolds number is 9500 based on the inlet velocity, the cylinder diameter and the kinematic viscosity of the noncavitation liquid. The Schneer–Sauer (SS) model is applied to cavitation simulation because it is more sensitive to vapor–liquid two-phase volume fraction than the Zwart–Gerber–Belamri (ZGB) model, according to theoretical analyses. The wake is quasiperiodic, with an approximate frequency of 0.2. It is found that the cavitation of vortices could inhibit the vortex shedding. Besides, the mutual aggregation of small-scale vortices in the vortex system or the continuous stripping of small-scale vortices at the edge of large-scale vortices could induce the merging or splitting of cavities in the wake.

The molten wood’s metal initial velocity variations effect on breaching simulation by MPS method

Series of MPS simulations have been conducted using two-dimensional geometry. The simulation was based on Sudha’s experiment (2018) about initial velocity variations on molten Wood’s Metal (WM). The molten WM would be flowed through nozzle with the diameter was 6 mm. It would impinge to the Woods Metal Plate (WMP) which 270 mm below the nozzle. The WMP diameter was 470 mm. The temperature of molten WM and WMP were set at 573 K and 300 K, respectively. The initial velocity of molten WM was varied at 0.327 m/s, 0.397 m/s, 0.498 m/s in the y-negative direction. The simulation was calculated by using 2D MPS with additional procedures such as heat transfer calculation and defining a new type of wall particle. The results showed some different spread patterns, leading edge and phase fraction change for each initial velocity. It can be concluded that with varying the initial velocity will affect on the radial spread pattern but not so much effect occurs on the phase volume fraction change.

Influence of Groove Structure Parameters Based on Optimal Mass Transfer Coefficient on Vaporization Characteristics and Sealing Performance of Liquid Film Mechanical Seals

In this study, a spiral groove liquid film vaporization model based on the viscosity–temperature equation, fluid internal friction, saturation temperature, and pressure relationship equation was established. Using a multiphase flow model based on the finite volume method, the influence of the change in the mass transfer coefficient on the vaporization of the liquid film was studied. Moreover, the influence law of structural parameter changes in liquid film vaporization characteristics and sealing performance was analyzed. The results indicate that, with an increase in the mass transfer coefficient, the average vapor phase volume fraction first increases and then gradually stabilizes. When calculating the average vapor phase volume fraction, it is necessary to consider the influence of the mass transfer coefficient, whereas its effect on the opening force and leakage can usually be neglected. Under the optimal mass transfer coefficient conditions, the average vapor phase volume fraction increases with an increase in the helix angle, groove-weir ratio, and groove depth. By comparison, with an increase in the groove-diameter ratio, the average vapor phase volume fraction first increases and then decreases. The opening force decreases with an increase in the helix angle, groove-to-weir ratio, and groove depth. On the other hand, it first decreases and then increases with an increase in the groove-diameter ratio. The leakage rate increases first and then stabilizes with an increase in the helix angle. Moreover, it increases continuously with an increase in the groove-diameter ratio, groove-weir ratio, and groove depth.

Microstructure Alteration in the High-Speed Machining of Titanium Alloy Involved With Tool Wear and Cryogenic Condition

The microstructure alteration generated in the high-speed machining of titanium alloy has significant influence on the performance, quality and service life of production. The prediction of grain size or phase distribution based on physics mechanism or the regression of experimental data have been reported in the process of static or quasi-static state. However, it is still a challenge to predict the phase transformation and grain growth process in machining accurately and effectively since it has characteristics of high strain, strain rate and temperature. In this paper, a novel FEM-based model involving with the microstructure alteration was introduced and implemented to predict finial grain size or phase result in the high-speed machining of Ti-6Al-4V alloys especially at the machined surface. The phase transformation process was proposed and discussed by considering tool wear and cryogenic condition at machined surface, while the microstructure results were displayed on the chip in the previous works. Firstly, the phase volume fraction and grain size were modelled by experimental data. Then the simulation based on the self-consistent method (SCM) was used to output strain and temperature distribution. Thirdly, the phase volume fraction and grain size expressions were transmitted into subroutine programs and the microstructure alteration process under the different cutting conditions were showed in the FE results. The simulation results of temperature, phase fraction and strain were compared against previous simulation or experiment results in published papers revealing good agreement. The proposed model was further to investigate the influence of tool wear and cutting temperature on machined surface. The results indicated that the tool wear increased heat at the flank face significantly resulting to β phase increasing and grain growth at machined surface and the cryogenic condition would lower temperature gradient as well as stress gradient contributing to reduce roughness and residual stress.

Dissolution of delta phase in Ni-based superalloy during linear friction welding: integrated multiphysics computational process modelling

Linear friction welding (LFW) is an increasingly popular solid-state joining method for challenging applications such as integrated blade disk of aero-engines. However, the influence of friction-generated heat on the material microstructural evolution, material deformation and resultant mechanical performance of the manufactured components is not well understood. A novel integrated multiphysics computational modelling is presented for predicting the component-scale microstructural evolution of IN718 alloy during LFW. A modified time-temperature equivalence formulation was implemented for predicting the evolution of the δ phase, which was coupled with thermomechanical modelling of the LFW process. There is reasonably good agreement between the computational modelling results of this paper and the experimental results from the literature in terms of δ phase volume fraction and weld temperature. The integrated multiphysics computational modelling predicts the influence of process parameters on thermomechanical and microstructural processes of IN718 LFW. By systematically analysing the influence of 10 different LFW process parameter configurations, the friction pressure was identified as the most influential process parameter determining the extent of δ phase dissolution and weld temperature during LFW.

Magnetic, electrical and mechanical properties of Fe40Mn40Co10Cr10 high entropy alloy

A prototypical, single-phase, and non-equiatomic high entropy alloy Fe40Mn40Co10Cr10 has been mechanically deformed at room and cryogenic temperatures. Plastic deformation was accommodated via crystallographic slip at room temperature while transformation induced plasticity (TRIP) has been observed in samples deformed at 77 K. The stress-induced martensitic transformation occurred from face-centered cubic (FCC) to hexagonal close-packed (HCP) structures. A detailed electron backscatter diffraction analysis was utilized to detect phase change and evaluate the evolution of the HCP phase volume fraction as a function of plastic strain. Physical properties of undeformed and deformed samples were measured to elucidate the effect of deformation-induced phase transitions on the magnetic and electrical properties of Fe40Mn40Co10Cr10 alloy. Relatively small magnetic moments along with non-saturating magnetic field dependencies suggest that the ground state in the considered material is ferrimagnetic ordering with coexisting antiferromagnetic phase. The temperature evolution of the coercive fields has been revealed for all samples. The magnitudes of the coercive fields place the considered system into the semi-hard magnetic alloys category. The temperature dependence of the zero-field cooled (ZFC) and field cooled (FC) magnetization was measured for all samples in the low field regime and the origin of irreversibility in ZFC/FC curves was discussed. Besides, the temperature dependence of the resistivity in all samples was measured and the possible conduction mechanisms were discussed.

HYDROPHOBIZATION OF SILICA PARTICLES WITH VARIOUS CATIONIC SURFACTANTS

Silica particles with a radius of 3-7 nm (Ludox and Aerosil) and 270 nm (synthesized by the Stöber method), modified with cetyltrimethylammonium bromide (CTAB) and hexylamine, were used to stabilize emulsions. The hysteresis angles θ of the particle selective wetting were measured by the sessile droplet method on the vertical surface or by the pulling a ball method at using a glass substrate modified by contact coagulation of silica. The contact angle at the boundary between the aqueous phase and the saturated hydrocarbon (octane, decane) reached the values θrec = 53 ± 2 ° and θadv = 116 ± 4 ° (the aqueous phase receding and advancing angle, respectively) with an increase in the initial concentration of long-chain CTAB to (1.4–9.5)·10–2 mmol/g of silica. With a further increase in CTAB concentration, a second reoriented layer was formed, which lowered the contact angle. Accordingly, using CTAB, only oil-in-water emulsions were obtained with the oil phase volume fraction Øoil = 0.5. The amount of short-chain hexylamine required to start stabilizing the emulsions turned out to be 2-3 orders of magnitude higher than the amount of CTAB. At using hexylamine, it was possible to increase the contact angle up to the values θrec ≈ θadv = 163 ± 12 ° at a concentration of 7-21 mmol/g. This is due to the fact that hexylamine is not characterized by formation of micelle or reoriented layers. Apparently, the adsorption of hexylamine is possible not only on dissociated silanol groups Si–OH, but also on siloxane groups Si–O–Si≡, which makes it possible to make the silica surface superhydrophobic. The measured contact angles were correlated with the region of stable oil-in-water and water-in-oil emulsions.