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For distant observers, black holes are trapped spacetime domains bounded by apparent horizons. We review properties of the near-horizon geometry emphasizing the consequences of two common implicit assumptions of semiclassical physics. The first is a consequence of the cosmic censorship conjecture, namely, that curvature scalars are finite at apparent horizons. The second is that horizons form in finite asymptotic time (i.e. according to distant observers), a property implicitly assumed in conventional descriptions of black hole formation and evaporation. Taking these as the only requirements within the semiclassical framework, we find that in spherical symmetry only two classes of dynamic solutions are admissible, both describing evaporating black holes and expanding white holes. We review their properties and present the implications. The null energy condition is violated in the vicinity of the outer horizon and satisfied in the vicinity of the inner apparent/anti-trapping horizon. Apparent and anti-trapping horizons are timelike surfaces of intermediately singular behavior, which manifests itself in negative energy density firewalls. These and other properties are also present in axially symmetric solutions. Different generalizations of surface gravity to dynamic spacetimes are discordant and do not match the semiclassical results. We conclude by discussing signatures of these models and implications for the identification of observed ultra-compact objects.

In this paper, we employ a new form of the extended uncertainty principle to investigate the thermal properties of the Schwarzschild and Reissner–Nordström. After we construct the formalism, we obtain the mass-temperature function for the Schwarzschild black hole. We follow a heuristic method to derive the entropy function after we obtained the heat capacity function. Then, we derive the mass-temperature and mass-charge-temperature functions of the Reissner–Nordström black hole in the new formalism. After we obtain the heat capacity and entropy functions, we present a comprehensive and comparative analysis of all these functions. We find that the deformation parameter changes drastically some of the thermodynamic function characteristics.

We review thermodynamic properties of modified gravity theories, such as $F(R)$ gravity and $f(T)$ gravity, where $R$ is the scalar curvature and $T$ is the torsion scalar in teleparallelism. In particular, we explore the equivalence between the equations of motion for modified gravity theories and the Clausius relation in thermodynamics. In addition, thermodynamics of the cosmological apparent horizon is investigated in $f(T)$ gravity. We show both equilibrium and nonequilibrium descriptions of thermodynamics. It is demonstrated that the second law of thermodynamics in the universe can be met, when the temperature of the outside of the apparent horizon is equivalent to that of the inside of it.

In this study, the effect of different arrangements of injectors on the injection of liquid water into the hot supersonic crossflow of cylindrical geometry on the performance and the rate of evaporation has been studied using a numerical method. The crossflow has a Mach of about 2 and a total temperature of 800K. At first, the penetration height and droplets produced by atomization in the supersonic flow are validated using the Lagrangian technique, and the results have been compared with the experiments. The usage of heat transfer equations and the evaporation model for the spray evaporation of droplets in the hot flow is also performed in the validation process, and the results are compared with the experimental results. Then, the injection into the examined geometry with four, six and eight injectors in three different arrangements was evaluated. The results indicate that employing an arrangement of eight injectors leads to the most significant reduction in total temperature, with average total temperatures decreasing to below 550K. The results demonstrate a 40% decrease in total pressure, with a decrease in Mach number to about 1 at the end of the cylinder. Additionally, the evaporation rate shows higher evaporation of water in the eight-injector arrangement compared to other arrangements.

The evaporation of fluid on solid surface is an important process in nature and industry. The high-efficiency heat transport between the working fluid and the solid surface can enhance the energy conversion and utilization. Thus, it is of great significance to study the mechanism of the evaporation phenomenon at the liquid–solid interface. In this study, the evaporation of refrigerant R32 on Pt surface is investigated by molecular dynamics (MD) method. The effects of the substrate temperature on the evaporation behavior of R32 are discussed in detail. It is found that R32 molecules mainly enter the vapor region by evaporation when the substrate temperature is no larger than 300 K. The evaporation rate increases with the increase of substrate temperature. The nucleate boiling and film boiling clearly occur when the substrate temperature is 350 K. The nanobubble formation, growth and coalesce is observed in the simulation. The heat flux changes rapidly when the system is boiling. As time goes on, a vapor film forms and then it leads to the heat transfer deterioration.

We have proposed and investigated a model of drying colloidal suspension drop placed onto a horizontal substrate in which the sol to gel phase transition occurs. The temporal evolution of volume fraction of the solute and the gel phase dynamics were obtained from numerical simulations. Our model takes into account the fact that some physical quantities are dependent on volume fraction of the colloidal particles.

R-410A's evaporation heat transfer and pressure drop data are provided for a 5.1 mm O.D. microfin tube having 40 fins with 18° helix angle and 40° fin apex angle. Tests were conducted for a range of quality (0.2–0.6), mass flux (260–433 kg/m²s), heat flux (10–20 kW/m²) and saturation temperature (8–12°C). Data are compared with smooth tube counterpart. It was found that both heat transfer coefficient and pressure drop increased as mass flux increased. The range of pressure drop penalty factor (1.10–1.70) was slightly smaller than that of heat transfer enhancement factor (1.39–1.79). Data are compared with available heat transfer and pressure drop correlations.

In this paper, condensation and evaporation characteristics of low global warming potential (GWP) refrigerants such as R-1234yf and R-1234ze series are reviewed. This review focuses on heat transfer and pressure drop in plate heat exchangers. Mass flux is considered as an important factor while saturation temperature is not for condensation and evaporation process in plate heat exchangers. The dryout phenomenon occurs occasionally and gives greatly harmful impact on evaporation heat transfer. It is found that R-1234yf and R-1234ze(E) give slightly lower heat transfer performance than R-134a for both condensation and evaporation processes. Generally, low GWP refrigerants presented in this review give lower heat transfer coefficient and higher frictional pressure drop than the conventional refrigerants. Nevertheless, R-1234ze(Z) gives superior heat transfer performance than other refrigerants in condensation. R-32 gives remarkable performance in evaporation, but it gives relatively high GWP compared to other low GWP refrigerants.

The Magneto-Optic Kerr Effect (MOKE) technique has been used to investigate the magnetic properties of Ni thin films, with thickness $t$ ranging from 9 to 163nm, evaporated onto several substrates (glass, Si (111), mica and Cu) with and without an evaporated Cu underlayer. The MOKE observations were correlated with the surface morphology inferred from Scanning Electron Microscope images and with the structural properties (grain size and strain). Some interesting behaviors of the coercive field (with values in the 2 to 151 Oe range), the squareness (between 0.1 and 0.91) and the saturation field (25–320 Oe) are observed as a function of $t$, the substrate and the Cu underlayer. A thickness-dependent stress-induced anisotropy is found in these films. The differences between the present MOKE results and the ones obtained from the Vibrating Sample magnetometer (VSM) are highlighted. The former describe the surface magnetism of these systems, while the latter are attributed to the whole volume of the sample.

We demonstrate that there exists an equilibrium description of thermodynamics on the apparent horizon in the expanding cosmological background for a wide class of modified gravity theories with the Lagrangian density f(R,ϕ,X), where R is the Ricci scalar and X is the kinetic energy of a scalar field ϕ. This comes from a suitable definition of an energy momentum tensor of the "dark" component obeying the local energy conservation law in the Jordan frame. It is shown that the equilibrium description in terms of the horizon entropy S is convenient because it takes into account the contribution of the horizon entropy Ŝ in non-equilibrium thermodynamics as well as an entropy production term.

The low GWP refrigerants attract a great attention due to various regulations such as Montreal protocol amendment and F-gas regulation. The amendment of Montreal protocol proposes to reduce the HFCs consumption by 85% until 2035 and F-gas legislation will reduce the HFCs consumption by 79% until 2030. In 2010, US DOE launched the low GWP refrigerant project which covers the lifecycle climate performance modeling, experimental evaluation and field testing. In 2015, Korea launched the project to develop the core technology of refrigeration system for low GWP ($<$100) refrigerants application. Since the project limited the GWP value less than 100, the applicable candidates (except for natural working fluids) are restricted about five refrigerants including R-1234yf, R-1234ze-(E), R444A, R-1233zd(E) and R-1336mzz. In the literature, to the best of the author’s knowledge, there is very limited information for pool boiling studies except R-1234yf. In present work, the cycle simulation and the prediction of pool boiling heat transfer coefficient for each refrigerant has been conducted. And the literature review of pool boiling for the refrigerants has been performed.

Heterogeneous crystallization resulted in low conversion efficiency and short service life has become one of the important challenges of desalination. Here, a fluoro-modified CNT@epoxy composite coating is developed to durably inhibit salt crystallization of photothermal sheet even in highly concentrated salt water. Typically, it can have stable evaporation efficiency of $\sim 1.70\mathrm{\text{kg}}\cdot {\mathrm{\text{m}}}^{-2}\cdot {\mathrm{\text{h}}}^{-1}$ without salt crystallization after continuously being operated for 40 cycles under one solar intensity in the 20 wt.% NaCl solution. That is mainly due to the Cassie state superhydrophobicity that can large increase the heterogeneous nucleation barrier quite close to the homogeneous one in salt water. This study expects to solve the existing problems of complex structure and short service time of seawater desalination units.

This study investigated the evaporation heat transfer and pressure drop characteristics of R32 in a horizontal multiport tube consisting of rectangular minichannels with straight microfins. The heat transfer coefficient and pressure drop were measured for a mass velocity range of 50–400kgm${}^{-2}$s${}^{-1}$ and heat flux range of 5–20kWm${}^{-2}$ at a saturation temperature of 15${}^{\circ }$C. The frictional pressure drop during an adiabatic two-phase flow was also measured for a mass velocity range of 50–400kgm${}^{-2}$s${}^{-1}$ and quality range of 0.1–0.9 at the same saturation temperature. The heat transfer coefficient increased with an increasing quality owing to the increase in forced convection. The dryout inception quality increased with the increase in mass velocity. The effects of heat flux on the heat transfer coefficient were small, except in a high-quality region. The heat transfer coefficient in a multiport tube with microfins was higher than that in a multiport tube without microfins in a high-quality region at a mass velocity of 200kgm${}^{-2}$s${}^{-1}$ and in a low-quality region at a mass velocity of 400kgm${}^{-2}$s${}^{-1}$. The effects of mass velocity and microfins on the frictional pressure drop were clarified. It is suspected that the effects of a microfin on the frictional pressured drop can be considered using the hydraulic diameter. The frictional pressure drop was shown to be in good agreement with previous correlations.