Preconditioned Conjugate Gradient Algorithm-Based 2D Waveform Inversion for Shallow-Surface Site Characterization

The full-waveform inversion (FWI) of a Love wave has become a powerful tool for shallow-surface site characterization. In classic conjugate gradient algorithm- (CG) based FWI, the energy distribution of the gradient calculated with the adjoint state method does not scale with increasing depth, resulting in diminished illumination capability and insufficient model updating. The inverse Hessian matrix (HM) can be used as a preprocessing operator to balance, filter, and regularize the gradient to strengthen the model illumination capabilities at depth and improve the inversion accuracy. However, the explicit calculation of the HM is unacceptable due to its large dimension in FWI. In this paper, we present a new method for obtaining the inverse HM of the Love wave FWI by referring to HM determination in inverse scattering theory to achieve a preconditioned gradient, and the preconditioned CG (PCG) is developed. This method uses the Love wave wavefield stress components to construct a pseudo-HM to avoid the huge calculation cost. It can effectively alleviate the influence of nonuniform coverage from source to receiver, including double scattering, transmission, and geometric diffusion, thus improving the inversion result. The superiority of the proposed algorithm is verified with two synthetic tests. The inversion results indicate that the PCG significantly improves the imaging accuracy of deep media, accelerates the convergence rate, and has strong antinoise ability, which can be attributed to the use of the pseudo-HM.

An empirical model for solvation based on surface site interaction points

A rule-based approach for assignment of Surface Site Interaction Points (SSIP) based on the chemical structure of a molecule provides a straightforward spreadsheet method for accurate calculation of solvation free energies.

Surface site density and utilization of platinum group metal (PGM)-free Fe–NC and FeNi–NC electrocatalysts for the oxygen reduction reaction

The gravimetric surface density and ORR catalytic turnover frequency of Fe–NC and Fe/Ni–NC catalysts were investigated. Both catalysts feature chemically identical Fe sites, but the presence of Ni lowered the gravimetric surface density of Fe sites.

Advancement of Hand Sanitizer gel for Killing Bacteria using Natural Extracts of leaves of Carica Papaya

The hand hygiene is an imperative rule and exercise in anticipation, control, and decrease of medical services obtained infections. The right hand washing and drying strategies stop the transmission chain of lethal microorganisms (from defiled surface/site) structure hands to different pieces of the body. The hand sanitization is superior support in preventing infections caused by various microorganisms and to get this, the utilization of hand sanitizer gets must in late conditions. The motivation behind the current investigation was to plan homegrown froth hand sanitizer joining the leaves concentrate of leaves of Carica papaya with multidimensional exercises. The definition is assessed against predefined microorganism (Candida albicans & Staphylococcusaure us) by culture affectability test. This detailing will be as froth. The explanation for consolidation of papaya leaves separate in froth detailing is that froth hand sanitizer doesn't effectively slide off the hands such as gel hand sanitizer. Likewise, froth sanitizer is simpler to spread around the hands. The extract of leaves of Carica papaya will be incorporated in the formulation. Papaya leaves are possible antibacterial that can be utilized in specific type off oods.