SARS-COV-2 acts as a test of Air Pollution, Lifestyle Disorders and Immune Tolerance dysregulation in human body

SARS-COV-2 is reported to be associated with severe immune dysregulation, delayed humoral responses and accelerated innate immune response mediated damages. As the pandemic is turning the world upside down, In order to address this disease we should first get an insight into the mechanism of action through which SARS-COV-2 is achieving the above said dysregulating or modulating effects on human immune system. T his article presents the basic or skeletal mechanism through which SARS-COV-2 dysregulates immune system by targeting innate immune system, adaptive immune system and different immune tolerance check points by dysregulating different miRNA’s and the preexisting conditions or comorbidities of the patients. This article comprises of the comparative and comprehensive literature review targeting all topics with the data available/reported till date in the scientific community.

A more realistic skeletal mechanism with compact size for n-butanol combustion in diesel engines

To accurately predict the combustion and emissions characteristics of a diesel engine fueled with n-butanol/diesel blends, a more realistic compact-sized skeletal mechanism with (149 species and 497 reactions) was developed in this study based on the decoupling method. It was generated by integrating the simplified fuel-related sub-mechanisms of n-butanol and diesel surrogates including n-dodecane, iso-cetane, iso-octane, toluene, and decalin. The same detailed core sub-mechanisms of C2-C3 and H2/CO/C1, in which the formation and oxidation of benzene (A1) and larger polycyclic aromatic hydrocarbon (PAH) up to coronene (A7) of alkanes, aromatics, cycloalkanes and alcohols were used. The PAH formation behavior of individual fuel components in the mechanism were analyzed in detail based on the methods of pathway analysis, rate of production and sensitivity analysis. The mechanism was extensively validated against ignition delay time, laminar flame speed, species profile and three-dimensional engine simulation. The results show that the effects of fuel types on the PAH formation are satisfactorily captured, and the combustion characteristics of n-butanol/diesel blends and each component are reliably reproduced by the current mechanism.

Computational Fluid Dynamics Study of a Nonpremixed Turbulent Flame Using openfoam: Effect of Chemical Mechanisms and Turbulence Models

This article presents a study of the influence of chemical mechanisms and turbulence models on Reynolds-averaged Navier–Stokes (RANS) simulations of the CH4/H2/N2-air turbulent diffusion flame, i.e., the so-called DLR-A flame. The first part of this study is focused on the assessment of the influence of four chemical models on predicted profiles of the DLR-A flame. The chemical mechanisms considered are as follows: (i) a C2 compact skeletal mechanism, which is derived from the GRI3.0 mechanism using an improved multistage reduction method, (ii) a C1 skeletal mechanism containing 41 elementary reactions amongst 16 species, (iii) the global mechanism by Jones and Lindstedt, (iv) and a global scheme consisting of the overall reactions of methane and dihydrogen. RANS numerical results (e.g., velocities, temperature, species, or the heat production rate profiles) obtained running the reactingFOAM solver with the four chemical mechanisms as well as the standard k − ɛ model, the partially stirred reactor (PaSR) combustion model, and the P − 1 radiation model indicate that the C2 skeletal mechanism yields the best agreement with measurements. In the second part of this study, four turbulence models, namely, the standard k − ɛ model, the renormalization group (RNG) k − ɛ model, realizable k − ɛ model, and the k − ω shear stress transport (SST) model, are considered to evaluate their effects on the DLR-A flame simulation results obtained with the C2 skeletal mechanism. Results reveal that the predictions obtained with the standard k − ɛ and the RNG k − ɛ models are in very good agreement with the experimental data. Hence, for simple jet flame with moderately high Reynolds number such as the DLR-A flame, the standard k-epsilon can model the turbulence with a very good accuracy.