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In a gas–water interaction problem, the nonlinear relationship between shock wave velocity is introduced into a Hugoniot curve, and a Mie–Grüneisen Equation of state (EOS) is established by setting the Hugoiot curve as the reference state. Unlike other simple EOS based on the thermodynamics laws of gas (such as the Tait EOS), the Mie–Grüneisen EOS uses reference states to cover an adiabatic impact relationship and considers the thermodynamics law separately. However, the expression of the EOS becomes complex, and it is not adaptive to many methods. A multicomponent Mie–Grüneisen mixture model is employed in this study to conquer the difficulty of the complex form of an EOS. In this model, some coefficients in the Mie–Grüneisen EOS are regarded as variables and solved using newly constructed equations. The performance of the Mie–Grüneisen mixture model in the gas–water problem is tested by low-compression cases and high-compression cases. According to these two tests, it is found that the numerical solutions of the shock wave under the Mie–Grüneisen EOS agrees with empirical data. When compared to other simple-form EOSs, it is seen that the Mie–Grüneisen EOS has slight advantages in the low-compression case, but it plays an important role in the high-compression case. The comparison results show that the solution of the simple-form EOS clearly disagrees with the empirical data. A further study shows that the gap between the Mie–Grüneisen EOS and other simple-form EOSs becomes larger as the initial pressure and particle velocity increase. The impact effects on the pressure, density and particle velocity are studied. Moreover, the gas–water interaction in a spherical coordinate plane and a two-dimensional coordinate is a significant part of our work. [ABSTRACT FROM AUTHOR]

In order to explore the possibility of CdS2 ${{{\rm C}{\rm d}{\rm S}}_{2}}$ monolayers as high‐performance gas sensors, the electronic properties and gas sensing performance of CH4 ${{{\rm C}{\rm H}}_{4}}$ , CO ${{\rm C}{\rm O}}$ , CO2 ${{{\rm C}{\rm O}}_{2}}$ , NO ${{\rm N}{\rm O}}$ , H2S ${{{\rm H}}_{2}{\rm S}}$ and Cl2 ${{{\rm C}{\rm l}}_{2}}$ gas molecules adsorbed on CdS2 ${{{\rm C}{\rm d}{\rm S}}_{2}}$ monolayers were investigated using a first‐principles approach. It was found that CH4 ${{{\rm C}{\rm H}}_{4}}$ , CO ${{\rm C}{\rm O}}$ and CO2 ${{{\rm C}{\rm O}}_{2}}$ had a weak chemisorption effect on the CdS2 ${{{\rm C}{\rm d}{\rm S}}_{2}}$ monolayer, while the physisorption of H2S ${{{\rm H}}_{2}{\rm S}}$ effectively altered the electronic properties and the work function of the CdS2 ${{{\rm C}{\rm d}{\rm S}}_{2}}$ monolayer. Compared with other gases, the CdS2 ${{{\rm C}{\rm d}{\rm S}}_{2}}$ monolayer has relatively high sensitivity to NO ${{\rm N}{\rm O}}$ , H2S ${{{\rm H}}_{2}{\rm S}}$ and Cl2 ${{{\rm C}{\rm l}}_{2}}$ , and the band gap of the system after adsorption changes significantly compared with the intrinsic CdS2 ${{{\rm C}{\rm d}{\rm S}}_{2}}$ monolayer, and the characteristics of the work function can effectively distinguish various gases. The results indicate that the CdS2 ${{{\rm C}{\rm d}{\rm S}}_{2}}$ monolayer has the ability to detect NO ${{\rm N}{\rm O}}$ , H2S ${{{\rm H}}_{2}{\rm S}}$ and Cl2 ${{{\rm C}{\rm l}}_{2}}$ gases with high sensitivity, especially for Cl2 ${{{\rm C}{\rm l}}_{2}}$ , and provide a theoretical basis for the development of CdS2 ${{{\rm C}{\rm d}{\rm S}}_{2}}$ monolayers for potential applications as gas sensors or scavengers for NO ${{\rm N}{\rm O}}$ , H2S ${{{\rm H}}_{2}{\rm S}}$ and Cl2 ${{{\rm C}{\rm l}}_{2}}$. [ABSTRACT FROM AUTHOR]

For a long time, fish school swimming has attracted a great deal of attention in biological systems, as fish schools can have complex hydrodynamic effects on individuals. This work adopted a non-iterative, immersed boundary–lattice Boltzmann method (IB–LBM). A numerical simulation of two-dimensional three-degree-of-freedom self-propelled fish, in side-by-side, staggered, and triangle formations, was conducted by adjusting spacing and motion parameters. A comprehensive analysis of individual speed gains and energy efficiencies in these formations was carried out. Furthermore, an analysis of the hydrodynamic characteristics of fish schools was performed, using instantaneous vorticity profiles and pressure fields. Certain studies have shown that passive interactions between individuals cannot always bring hydrodynamic benefits. The swimming efficiency of side-by-side formations in the same phase gradually increases as the distance decreases, but it also brings certain burdens to individuals when the phases are different. This paper also shows that the roles of passive interactions, spacing, and deflections affect fish school subsystems differently. When the low-pressure areas created by a wake vortex act on one side of an individual's body, the tail-end fish are good at gaining hydrodynamic benefits from it. This effect is not universal, and the degree to which individuals benefit from changes in exercise parameters varies. This study provides a theoretical basis for bioinspired robots, as well as providing certain insights into the mechanism of collective biological movement. [ABSTRACT FROM AUTHOR]

Herein, 2D doped PbSe is used to design a gas sensor to monitor the presence of SO2 and Cl2. The stability and feasibility of doped materials are studied. Based on first principles, the adsorption of toxic gases by 2D doped PbSe is verified by density of states, Bader charge, electron localization function, and differential charge density calculations. The calculation results show that Ge1Ge3 and Sn1 are suitable for adsorption of Cl2, and the bandgap decreases by roughly 69%. Ge1Ge2 and Sn1 are suitable for adsorption of SO2, and the bandgap decreases by roughly 38%. This provides the possibility of designing gas sensors for SO2 and Cl2 based on 2D doped PbSe. [ABSTRACT FROM AUTHOR]

The structural and electronic properties of SnTe monolayer after the adsorption of gas molecules (CH4, CO2, NH3, CO, H2S, NO, SO2, NO2 and Cl2) were investigated by first‐principles calculations based on density functional theory (DFT). The results showed that SO2, NO, NO2 and Cl2 were chemisorbed on SnTe monolayer with strong adsorption energies. In addition, because of the high sensitivity of the adsorption of SO2 and NO gases on SnTe monolayer, the bandgap of the developed system changed significantly, with a reduction of 22.88 % and 71.65 %, respectively. The results indicate that SnTe monolayer has highly sensitive SO2 and NO gas detection capability, especially for NO. And it can act as a disposable gas sensor or metal‐free catalyst for the detection and catalysis of pollution gases, such as NO2 and Cl2. [ABSTRACT FROM AUTHOR]

Nowadays, the ground-coupled heat pump (GCHP) systems have been recognized as one of the most energy-efficient systems for heating, cooling and hot water supply in both residential and commercial buildings. However, the heat transfer of ground heat exchanger (GHE) involves in large spatial scales, long time span and complex influential factors. We develop a data mining framework constructed by using 1998 experimental data to study the effects of 12 input variables composed of seven borehole parameters, two U-tube parameters, two ground parameters and one circulating liquid parameter to accurately predict the heat transfer performance of GHE for GCHP systems in 10 years. Hence, selecting a suitable input configuration to improve the energy efficiency has important sustainability benefits. The role of each of independent variable explaining the output variables is analyzed by partial least squares regression. Furthermore, support vector regression and M5 Model Tree are, respectively, used to predict the heat transfer performance. Extensive simulations show that we can predict the average quantity of heat exchanger, temperature of ground around GHE, inlet temperature of heat pump unit with very low level of error. [ABSTRACT FROM AUTHOR]

In this paper, we use 2D PbSe to design a gas sensor to monitor the presence of SO 2 and Cl 2 . We use first principles to verify the feasibility of this material, such as atomic structure, band gap, differential charge density and Bader charge. The results show that 2D PbSe can distinctly adsorb SO 2 and Cl 2 . Furthermore, the adsorption of SO 2 and Cl 2 will affect the electronic structure of 2D PbSe, and some electrons in the PbSe are transferred to gas atoms. The band gap of the system after adsorption is smaller than that of the PbSe before adsorption. The band gap of single layer PbSe decreases by 41.92% after SO 2 adsorption and 60.61% after Cl 2 adsorption. The band gap of multi-layer PbSe decreases by 72.97% after SO 2 adsorption and 43.24% after Cl 2 adsorption. This shows that single layer PbSe is more sensitive to Cl 2 and multi-layer PbSe is more sensitive to SO 2 . It provides a potential possibility for designing gas sensors for SO 2 and Cl 2 based on 2D PbSe., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)