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Although green vegetables are valuable sources of essential elements, and are safe in that they lack harmful elements, they are high in oxalic acid, increasing the risk of urolithiasis. We performed elemental analyses on spinach (Spinacia oleracea L), Malabar nightshade (Basella alba), and water Morning Glory (Ipomoea aquatica), which contain large amounts of oxalic acid, and compared the data to those of Japanese mustard spinach (Brassica rapa var. perviridis), which is the second most commonly consumed green vegetable (after spinach) in Japan. We focused on concentrations of Ca, Mg, and Sr that suppress the formation of ureteral stones (calculi). The calcium concentration in spinach was $6,883\pm 367\mu$g/g in leaves and $2,190\pm 159.2\mu$g/g in stalks, and the level in Japanese mustard spinach were $16,360\pm 957\mu$g/g in leaves and $20,120\pm 1,226\mu$g/g in stalks. The overall Sr concentration in Japanese mustard spinach was thus 10-fold higher than in spinach, but the Mg concentration was lower than that in spinach. The concentrations of Ca and Sr in Malabar nightshade and water Morning Glory were 3- to 5-fold higher than in spinach. As the former vegetables are consumed much less often than spinach, the risk of urolithiasis is low. We explored how the concentrations of these elements changed after boiling.

Understanding energy transfer between working fluid and vapor is a critical issue in absorption refrigeration and thermophysics for the aim of intensifying heat conversion. However, it is difficult to achieve by experimental measurements due to the difficulty in catching the detailed and accurate modeling information, e.g., specific working fluid, and its underlying molecular mechanism. In order to study the evaporation and boiling behavior of refrigerant mixture from the microscopic point of view, the nanofilm consisting of different working fluids, with the evaporation model of R32/R1234ze (E) on metal wall, was established by utilizing molecular dynamics (MD) method. The effect of different mole ratios, i.e., pure R32, 3:1, 1:1, 1:3, pure R1234ze (E), on the evaporation and boiling behavior of mixtures was analyzed. The results show that the probability of explosive boiling decreases with the decrease of R32 molecular mole ratios. Thus, in turn, the performance of refrigerant mixture is observed to be better than that of pure refrigerant. Insights from this simulation research could provide an effective reference for the MD interactions and have potential benefit in developing efficient and sustainable processes for industries to minimize the chemical usage and environmental damage.

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.

A new mathematical model for non-equilibrium evaporation/condensation including boiling effect is proposed. A simplified differential-algebraic system of equations is obtained. A code to solve numerically this differential-algebraic system has been developed. It is designed to solve both systems of equations with and without the boiling effect. Numerical calculations of ammonia–water systems with various initial conditions, which correspond to evaporation and/or condensation of both components, have been performed. It is shown that, although the system evolves quickly towards a quasi-equilibrium state, it is necessary to use a non-equilibrium evaporation model to calculate accurately the evaporation/condensation rates, and consequently all the other dependent variables.

The existing artificial and chemical refrigerants have been phased out due to environmental concerns, and they have been replaced with environmentally friendly refrigerants. Among them, carbon dioxide, ammonia, and hydrocarbons are paid attention as next generation refrigerants, and their application has been widely expanded. Therefore, in this paper, the latest studies of flow boiling and condensation heat transfer characteristics of carbon dioxide, ammonia, and hydrocarbon are reviewed. The heat transfer characteristics of ammonia and hydrocarbon show the relatively similar trends with the conventional refrigerants compared to those of carbon dioxide. The general trends and recommendable models of flow boiling and condensation heat transfer with carbon dioxide, ammonia, and hydrocarbons are summarized.

To study the washing mechanism of laminated plates with solvent vapor, we have experimentally investigated evaporation dynamics of liquid confined between solid plates under reduced pressure. As the test liquid, we use deionized water and several organic compounds. To visualize the fluid motion in the thin gaps, we adopt glass plates. When a test liquid is sandwiched between a normal (float) glass plate and a ground (sand-blasted) one, vertically incident light passes through the plates without much scattering; once the liquid starts to evaporate, dried rough surface of the ground glass scatters the light and we can monitor the flow pattern. Based on the transmitted light intensity, the whole plate area is categorized into three regions; completely wet, completely dry, and semi-dry one; the last one is supposed to be the state that thin liquid film spreads on the plate. In the case of water, many tiny spots of semi-dry region appear and expand at the initial stage, which is probably cavitation of dissolved gas. In organic liquid cases, evaporation seems to start from the edges of the plates. At a later stage, the semi-dry region expands with complicated branching patterns. In all cases, occasional rapid motions of liquid were observed, which correspond to two-dimensional flash boiling. We also investigated the influence of the control pressure, the surface roughness, and the plate deformation.

The objective of the present study was to investigate the effects of various parameters, i.e., concentration of salt solution (2, 3, 4% (w/v)), boiling time (3, 5, 7 minutes) and drying air temperature (80, 100, 120°C) on the kinetics of drying and various quality attributes of shrimp, namely, color, texture, shrinkage and rehydration ability, during drying in a jet-spouted bed dryer. Small shrimp (350-360 shrimp/kg) was boiled and then dried until its moisture content was around 25% (d.b.). It was found that the color changes, toughness and shrinkage of shrimp increased while the rehydration ability decreased with an increase in the concentration of salt solution and boiling time.