The two-phase flow in micro/mini channels is of fundamental importance for many interesting applications, such as cooling of micro-electronic components and devices by a compact heat exchanger, material processing and thin-film deposition technology, bioengineering, and biotechnology. This article discusses significant developments made in the past ten years by researchers in the fields of pool boiling and convective boiling, using water, nanofluids, and refrigerants as the working fluids. The literature's data is examined in terms of improvements and declines in the critical heat flow and nucleate boiling heat transfer.Conflicting data have been presented in the literature on the effect that nanofluids/refrigerants have on the boiling heat-transfer coefficient; however, almost all the researchers have noted an enhancement in the critical heat flux during nanofluid/refrigerant boiling. Several researchers have observed nanoparticle deposition at the heater surface, which they have related to the critical heat flux enhancement.

Proposed herein is an environment-friendly method to realize oil/water separation. Nylon mesh is exposed to atmospheric pressure plasma for surface modification, by which micro/nano structures and oxygen-containing groups are created on nylon fibers. Consequently, the functionalized mesh possesses superhydrophilicity in air and thus superoleophobicity underwater. The water pre-wetted mesh is then used to separate oil/water mixtures with the separation efficiency above 97.5% for various oil/water mixtures. Results also demonstrate that the functionalized nylon mesh has excellent recyclability and durability in terms of oil/water separation. Additionally, polyurethane sponge slice and polyester fabric are also functionalized and employed to separate oil/water mixtures efficiently, demonstrating the wide suitability of this method. This simple, green and highly efficient method overcomes a nontrivial hurdle for environmentally-safe separation of oil/water mixtures, and offers insights into the design of advanced materials for practical oil/water separation.

A large number of publications devoted to a new class of materials - high-entropy alloys (HEA), is associated with their unique chemical, physical and mechanical properties both in cast materials and in various classes of coatings and refractory compounds. As a result of the research, the features of solid-soluble high-entropy alloys based on BCC and FCC phases have been revealed. These include the role of the most refractory element in the formation of the lattice parameter, the relationship of distortion with elastic deformation, and the contribution of the enthalpy of mixing to the strength and modulus of elasticity. This made it possible, on the basis of Hooke's law, to propose a formula for determining the hardness of the HEA based on the BCC and FCC phases. Based on the fact that with an increase in temperature in high-entropy alloys, the values of the modulus of elasticity, distortion and enthalpy of mixing will obey the same laws, a formula is proposed for determining the yield strength depending on the test temperature of solid-soluble HEA based on BCC and FCC phases. A formula based on the role of the most fusible metal in the alloy is proposed to calculate the melting point of solid-soluble materials.

The use of porous media to simplify the thermohydraulic of a nuclear reactor is the topic of recent research. As a case study, the rector of 200 kW installed at Missouri University of Science and Technology is modeled in this paper. To help this objective, a fundamental CFD examination was completed to supplement the neutronics investigation on the present reactor. Characteristics of thermal energy removal from a typical research reactor are modeled by numerical thermal transport in porous media. The neutron flux is modeled by the nodal expansion method. For the thermo-hydraulic part, a three-dimensional governing equation is solved by an iterative method to find the steady-state solution of fluid flow and temperature in loss of coolant condition where the heat produced in the reactor core is removed by free convection. The profiles of heat flux for various power levels are benchmarked. Pressure, temperature, and velocity contours in the power passage were assessed at 300 kW and 500 kW power levels. To reduce the computational cost, a porous media approach for the whole geometry was utilized. The numerical results agree with the experimental results. The developed model can be used for safety and reliability analysis for various loss of coolant accidents.

The Method of Discretization in Time (MDT) is a hybrid numerical technique intended to alleviate upfront the computational procedure of timedependent partial differential equations of parabolic type upfront. The MDT engenders a sequence of adjoint second order ordinary differential equations, wherein the space coordinate is the independent variable and time becomes an embedded parameter. Essentially, the adjoint second order ordinary differential equations are considered of “quasistationary” nature. In this work, the MDT is used for the analysis of unsteady heat conduction in regular bodies (large wall, long cylinder and sphere) accounting for nearly constant thermophysical properties, uniform initial temperature and surface heat flux. In engineering applications, the surface heat flux is customarily provided by electrical heating, radiative heating and pool fire heating. It is demonstrated that the approximate, semianalytical temperature solutions of the first adjoint “quasistationary” heat conduction equations using the first time jump are easily obtainable for each regular body. For enhanced acccuracy, regression analysis is applied to the deviations of the dimensionless surface temperature as a function of the dimensionless time for each regular body.

A new method has been proposed to estimate top heat losses of vertical flat plate liquid/air collectors with double glazing. Empirical relations have been developed for the temperatures of glass covers, thus facilitating the calculation of individual heat transfer coefficients. The values of individual heat transfer coefficients therefore obtained can be used in the proposed analytical equation for the estimation of the top heat loss coefficient of the vertical collector with double glazing. The analytical equation has been developed for collector tilt angle of 60 to 90 degrees, plate temperature of 323 K to 423 K, absorber coating emittance of 0.1 to 0.95, air gap spacing of 20 mm to 50mm between the plate and inner glass cover, air gap spacing of 20 mm to 50mm between glass covers, wind heat transfer coefficient of 5 W/m2K to 30 W/m2K, and ambient temperature of 263K to 313K. The accuracy of the analytical equation has been validated for the said range of variables in comparison to numerical solutions, and the values of the top heat loss coefficient are found to be within 2.5 percent compared to numerical solutions.

Work is reported on thermal-induced redshifts of quantum particle plasmon. The redshifts are predicted to be caused indirectly by the quantum size effects. The particles are enlarged when temperature increases, and consequently, quantum size effects modify the plasmon but not the band structure. It has been modeled for metallic quantum particles. The results are also instructive to other quantum systems, such as complex molecules. Every electron inside the quantum particle is taken into account. Tiny quantum size effects are harvested, and the redshift becomes significant. Experimental evidence is also given for the spectral redshift. Faujasite zeolites were synthesized. Optical spectroscopy has been carried out, and the resulting spectra showed a significant redshift with the increase in temperature.

In response to the prevailing energy crisis, this research focuses on elevating the potential of lithium niobate (LN) thin films for advanced optoelectronic applications. Employing electron beam evaporation, films undergo precise annealing (700°C to 1100°C), revealing a structural evolution through X-ray diffraction—crystallite sizes transition from 69.34 nm (unannealed) to 47.90 nm (1100°C). Scanning electron microscopy captures the transformation from coarse grains to photonic crystal clusters, while energy dispersion X-ray analysis discloses LN's composition (97.27 wt.% oxygen, 2.73 wt.% niobium). Rutherford backscattering spectroscopy illustrates surface damage post-Helium ion implantation, proportionate to depth. UV-VIS spectrophotometry highlights a significant blue shift in the optical band gap (3.70 eV to 2.52 eV), with further reduction at 700°C (2.48 eV) and a climactic shift at 1100°C (2.68 eV). This study not only addresses the pressing energy crisis but also emphasizes the indispensable role of lithium niobate in shaping the future of optoelectronics. It provides insights into tailoring LN properties for sustainable advancements in optoelectronic devices, marking a crucial chapter in our collective journey towards energy resilience. The urgency of innovation in the face of global challenges is underscored, marking a crucial chapter in our collective journey towards energy resilience.