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A Mesoscopic Approach for Evaporation in Capillary Porous Media
Published in Rui Wu, Marc Prat, Mass Transfer Driven Evaporation from Capillary Porous Media, 2023
Debashis Panda, Shubhani Paliwal, Supriya Bhaskaran, Githin Tom Zachariah, Evangelos Tsotsas, Abdolreza Kharaghani, Vikranth Kumar Surasani
In the last few decades, lattice Boltzmann methods (LBMs) (Al–Ghoul et al., 2004; Chopard and Hoekstra, 2004) emerged as a direct numerical simulator for the multiphase flows in the porous medium. The LBM has major advantages over traditional pore-scale modelling techniques. Firstly, it emerges from the Boltzmann kinetic molecular dynamics – a more foundational entity than a conventional scaled modelling technique. In other way, one can view the LBM as a mesoscopic approach by incorporating the interparticle forces. This perception holds LBM a basic yet a better method for implementing surface tension, capillary regime, thermal effects and fluid–solid interactions. Secondly, the pressure in the LBM is expressed directly from the non-ideal equation of states for the multiphase fluids. Hence, the pressure is obtained as a function of density in the LBM unlike other techniques, where the Poisson equation (computationally expensive) is required to be solved to obtain the pressure field. Thirdly, the no-slip boundary condition is easily implemented in the solid domain. Thus, it becomes easier to handle complex geometry like void space in porous medium. Finally, most of the operation in the LBM is local to a given spatial node. Therefore, the LBM is easily parallelizable too.
Gas Filtration Theory
Published in Michael J. Matteson, Clyde Orr, Filtration, 2017
Similarly, the interface mass transfer by small particles can be described by a local rate of filtration T and a total rate of filtration in systems with complex geometry (filters of arbitrary structure). The local rate of filtration T-called the local rate of removal of particles per unit volume of filter by Spielman and Goren [25]–gives the number of particles captured by a unit volume of the filter in unit time. Hence, the total rate of filtration is Φ = ∫VfT dVf, where Vf is the volume of the filter. The rate Φ is related to the flux of particles entering a filter of surface A in unit time, N1U0A, by () Φ=EN1U0A
Flexible Protective Armor: Modern Designs
Published in Magdi El Messiry, Protective Armor Engineering Design, 2019
Analytical methods have been used to study ballistic impact. The fabric has a very complex geometry. Under the impact loading conditions, the deformation of fabric depends on the interaction between the fabric architect behavior under the dynamical forces and the change in the mechanical properties of the fibers. In most cases for bulletproof armors, the bullet will be faced by several resisting forces after touching the surface of the fabric, as indicated in Figure 6.10.
Airflow and contaminant transport in innovative personalized ventilation systems for aircraft cabins: A numerical study
Published in Science and Technology for the Built Environment, 2022
Chanfiou Ahmed Mboreha, Sun Jianhong, Wang Yan, Sun Zhi
It can be seen from Figure 14, that the PVs coupled with the DV (PV-1, PV-2, and PV-3) show a lower contaminant concentration than the PVSs coupled with the MV (PV-4, PV-5, and PV-6). Among the six proposed PVs, PV-1 had the lowest contaminant concentration and PV-5 had the highest levels of contaminants circulating. Considering the above results, PV-1 is preferred for virus protection in the aircraft cabins. Several previous studies (Ahmed Mboreha, Tytelman et al. 2021; Yan et al. 2017; You et al. 2017; Zhang et al. 2009) have demonstrated that precisely forecasting temperature, airflow, and pollutant concentration distribution in actual or full-scale-mockup airplane cabins is difficult. Due to the restricted space in the cabin and the complex geometry, it is particularly interesting to precisely evaluate the boundary conditions. The CFD simulations, on the other hand, were able to represent the overall trend of the air, temperature, and pollutant concentration distribution.
Impact of glass fibre on hydromechanical behaviour of compacted sand–bentonite mixture for landfill application
Published in European Journal of Environmental and Civil Engineering, 2021
Krishanu Mukherjee, Anil Kumar Mishra
From the failure pattern of soil specimen, under a confining pressure of 100 kPa as shown in Figure 12, it can be seen that the specimen undergoes shear failure with development of clear rupture in the presence fibre. As seen in Figure 12(a), the failure plane of unreinforced soil was developed from the bottom and undergoes shear failure. With the inclusion of 0.5% of fibre the shear failure occurs (Figure 12(b)) more progressively toward central region but a further addition of 1% and 1.5% of fibre (Figure 12(c,d)), shear failure was more clear within the central zone. It was clear that SB10 with higher content of fibre exhibits a well-defined failure plane, indicating that randomly distributed fibres were stitched up by a potential rupture within the soil mass. It can be noticed that the fibre gets pulled out when loading was exceeded. This complex geometry was accountable for the surface rupture of the fibre. The surface rupture of the fibre was recorded by FESEM and presented in Figure 13 comparing the fibre after and before shear.
Interactions of nitrogen-donor biomolecules with copper(II) complexes in Tris buffer
Published in Journal of Coordination Chemistry, 2020
Enisa Selimović, Andrei V. Komolkin, Diana A. Davletbaeva, Andrei V. Egorov, Tanja V. Soldatović
One fundamental, unresolved question in this field is the specific behavior of Cu-complexes at physiological conditions (intracellular or extracellular conditions). Because many biological reactions show pH dependence, it is essential to work under the appropriate conditions (dilute aqueous solutions at or near 310 K, presence of physiological buffers, rather high molecular mobility, distortions of local symmetry of complexes, etc.). Moreover, in the mobile phase, several structures of complexes can coexist. However, a shift of isomeric equilibrium and change of relative concentrations for such species might be observed upon freezing. Also, the presence of buffer molecules can affect the solution behavior of Cu-complexes in several ways: (i) by changing the ligands coordination tendency toward complex, (ii) by causing a distortion of an existing complex geometry, (iii) having an influence on the solution conformational dynamics and complex mobility, and (iv) in the case of so-called “coordinating” solvents, the complex formation with buffer molecules may be considerable. These factors can lead to complex formation mechanisms that are specific for the given buffer.