TBL-induced energy transmission into a double wall backed enclosure system computed in a cloud-based Python-FE environment

We propose a fully coupled numerical model to predict turbulent boundary layer (TBL) induced energy transmission behavior for a double-wall backed enclosure system in a finite element (FE) framework computed in cloud-based Python environment. Goody single point wall-pressure spectrum and Corcos spatial correlation function are used to generate the TBL cross-power spectra. Mindlins first order shear deformation model is considered for the panels and a fully coupled TBL-structure-acoustic model is developed using the FE approach to predict the acoustic power level inside the enclosure for variable gap distance between the panels. The model is developed in a way to capture the contribution of orthotropic lamina sequence, frequency-dependent structural damping, and stiffening orientation in predicting the energy transmission into a double-wall backed enclosure. Thus, a new numerical model is presented that enables the designers with more precise energy transmission quantification with greater flexibility in terms of the number of panel leaves, geometry, and boundary conditions of the enclosure system, backed by double wall made of isotropic or orthotropic laminates.Comment: 9 pages, 2 figures. arXiv admin note: substantial text overlap with arXiv:2208.1115

Reduction in turbulence-induced non-linear dynamic vibration using tuned liquid damper (TLD)

In the present research work, an attempt is made to develop a coupled non-linear turbulence-structure-damper model in a finite volume-finite difference (FV-FD) framework. Tuned liquid damper (TLD) is used as the additional damping system along with inherent structural damping. Real-time simulation of flow-excited bridge box girder or chimney section and the vibration reduction using TLD can be performed using the developed model. The turbulent flow field around a structure is modeled using an OpenFOAM transient PISO solver, and the time-varying drag force is calculated. This force perturbs the structure, causing the sloshing phenomena of the attached TLD, modeled using shallow depth approximation, damping the flow-induced vibration of the structure. The structural motion with and without the attached TLD is modeled involving the FD-based Newmark-Beta method using in-house MATLAB codes. The TLD is tuned with the vortex-shedding frequency of the low-Reynolds number flows, and it is found to be reducing the structural excitation significantly. On the other hand, the high-Reynolds number turbulent flow exhibits a broadband excitation, for which by tuning the TLD with few frequencies obtained through investigations, a good reduction in vibration is observed.Comment: 6 pages, 12 figure

Black Tea and Theaflavins Assist Healing of Indomethacin-Induced Gastric Ulceration in Mice by Antioxidative Action

The healing activities of black tea (BT) and the theaflavins (TF) against the indomethacin-induced stomach ulceration were studied in a mouse model. Indomethacin (18 mg/kg, p.o.) administration induced maximum ulceration in the glandular portion of the gastric mucosa on the 3rd day, accompanied by increased lipid peroxidation and protein oxidation, depletion of thiol-defense and mucin, as well as reduced expressions of cyclooxygenases (COX) and prostaglandin (PG) E synthesis in the gastric tissues, and plasma total antioxidant status of mice. Treatment with BT (40 mg/kg), TF (1 mg/kg), and omeprazole (3 mg/kg) produced similar (74%–76%) ulcer healing, as revealed from the histopathological studies. Treatment with all the above samples reversed the adverse oxidative effects of indomethacin significantly. BT and TF also enhanced the PGE synthesis by augmenting the expressions of COX 1 and 2, but did not modulate acid secretion

Green tea processing by pan-firing from region-specific tea (Camellia sinensis L.) cultivars - a novel approach to sustainable tea production in Dooars region of North Bengal

ABSTRACT: The black crush-tear-curl (CTC) tea constitutes the bulk tea production in Dooars region of North Bengal while green tea processing is confined to fewer tea estates, however, recent trends of the tea industry indicate gradual inclination towards green tea production. Our novel research findings on pan-fired green teas from twelve cultivated region-specific tea varieties at three flushes and data analysis of chemical and sensory quality attributes showed diversity in the leaf chlorophyll and carotenoid contents, as well as wide ranges of variation in green tea quality constituents including Polyphenols, Total Catechins, Catechin fractions, caffeine, free amino acids, Polyphenol to Amino acids ratio, Soluble Solid content and tasters’ quality scores. Most parameters differed significantly among the tea cultivars and between the three flushes within a certain cultivar. This study has highlighted the role of genetic variability of tea cultivars, processing conditions, and seasonal influence in determining green tea quality