Dynamic Response of Heterogeneity and Reinforcement on the Propagation of Torsional Surface Waves

This paper aims to investigate the effect of reinforcement and heterogeneity on the propagation of torsional surface waves. Geometry of the problem is consists of heterogeneous fibre-reinforced layer lying over a heterogeneous isotropic half-space. Heterogeneity in the layer is caused due to exponential variation of elastic parameters whereas quadratic variation in elastic parameters is considered for half-space. Dispersion relation for torsional surface waves has been obtained and matched with classical Love wave equation by taking an isotropic homogeneous layer lying over an isotropic homogeneous half-space. Some existing results have been deduced as particular case of the present study. Velocity profile of surface waves is compared for both, reinforced and reinforced free cases. Numerical examples have been discussed by taking steel fibre-reinforced material. Graphical representation has been made to exhibit the findings

Evaluating air quality and criteria pollutants prediction disparities by data mining along a stretch of urban-rural agglomeration includes coal-mine belts and thermal power plants

Air pollution has become a threat to human life around the world since researchers have demonstrated several effects of air pollution to the environment, climate, and society. The proposed research was organized in terms of National Air Quality Index (NAQI) and air pollutants prediction using data mining algorithms for particular timeframe dataset (01 January 2019, to 01 June 2021) in the industrial eastern coastal state of India. Over half of the study period, concentrations of PM2.5, PM10 and CO were several times higher than the NAQI standard limit. NAQI, in terms of consistency and frequency analysis, revealed that moderate level (ranges 101–200) has the maximum frequency of occurrence (26–158 days), and consistency was 36%–73% throughout the study period. The satisfactory level NAQI (ranges 51–100) frequency occurrence was 4–43 days with a consistency of 13%–67%. Poor to very poor level of air quality was found 13–50 days of the year, with a consistency of 9%–25%. Random Forest (RF), Support Vector Machine (SVM), Bagged Multivariate Adaptive Regression Splines (MARS) and Bayesian Regularized Neural Networks (BRNN) are the data mining algorithms, that showed higher efficiency for the prediction of PM2.5, PM10, NO2 and SO2 except for CO and O3 at Talcher and CO at Brajrajnagar. The Root Mean Square Error (RMSE) between observed and predicted values of PM2.5 (ranges 12.40–17.90) and correlation coefficient (r) (ranges 0.83–0.92) for training and testing data indicate about slightly better prediction of PM2.5 by RF, SVM, bagged MARS, and BRNN models at Talcher in comparison to PM2.5 RMSE (ranges 13.06–21.66) and r (ranges 0.64–0.91) at Brajrajnagar. However, PM10 (RMSE: 25.80–43.41; r: 0.57–0.90), NO2 (RMSE: 3.00–4.95; r: 0.42–0.88) and SO2 (RMSE: 2.78–5.46; r: 0.31–0.88) at Brajrajnagar are better than PM10 (RMSE: 35.40–55.33; r: 0.68–0.91), NO2 (RMSE: 4.99–9.11; r: 0.48–0.92), and SO2 (RMSE: 4.91–9.47; r: 0.20–0.93) between observed and predicted values of training and testing data at Talcher using RF, SVM, bagged MARS and BRNN models, respectively. Taylor plots demonstrated that these algorithms showed promising accuracy for predicting air quality. The findings will help scientific community and policymakers to understand the distribution of air pollutants to strategize reduction in air pollution and enhance air quality in the study region

Effect of Layer-Stacking on the Electronic Structure of Graphene Nanoribbons

The evolution of electronic structure of graphene nanoribbons (GNRs) as a function of the number of layers stacked together is investigated using \textit{ab initio} density functional theory (DFT) including interlayer van der Waals interactions. Multilayer armchair GNRs (AGNRs), similar to single-layer AGNRs, exhibit three classes of band gaps depending on their width. In zigzag GNRs (ZGNRs), the geometry relaxation resulting from interlayer interactions plays a crucial role in determining the magnetic polarization and the band structure. The antiferromagnetic (AF) interlayer coupling is more stable compared to the ferromagnetic (FM) interlayer coupling. ZGNRs with the AF in-layer and AF interlayer coupling have a finite band gap while ZGNRs with the FM in-layer and AF interlayer coupling do not have a band gap. The ground state of the bi-layer ZGNR is non-magnetic with a small but finite band gap. The magnetic ordering is less stable in multilayer ZGNRs compared to single-layer ZGNRs. The quasipartcle GW corrections are smaller for bilayer GNRs compared to single-layer GNRs because of the reduced Coulomb effects in bilayer GNRs compared to single-layer GNRs.Comment: 10 pages, 5 figure

Effect of sodium lauryl sulphate micelle in the oxidation of <i>dl-</i>mandelicacid by Cr(VI)

660-666dl-Mandelicacid on oxidation by Cr(VI) in the absence and presence of sodium lauryl sulphate (NaLS) follows a route conforming to Michaelis-Menten kinetics. Rate data in the presence of [H+] show an acid dependent and acid independent path. Entropy of activation is found to be negative. Rate of oxidation is mildly enhanced in the presence of increasing concentration of NaLS upto the CMC value of NaLS beyond which rate decreases. An attempt has been made to rationalise the observations

The Spatio-Temporal Onset Characteristics of Indian Summer Monsoon Rainfall and Their Relationship with Climate Indices

Regional variations of monsoon onset dates across India were analyzed for 67 years (1951–2017) under different modes of climate variations, i.e., El Niño, La Niña, and the Indian Ocean Dipole (IOD), along with flood and drought years using the objective method and statistical techniques. Monsoon onset analysis revealed that the northern, northeastern, and southern parts were highly susceptible to the early onset of La Niña, and the northern and northern northwest parts were highly susceptible to the early onset of El Niño. The onset dates were early (late) in the sub-regions of the central, southern, and northeastern (northern, northwestern, and western) parts of India during flood (drought) years. Further, onset dates in flood years occurred earlier than those in La Niña years, and onset dates in drought years were later than those in El Niño years. The onset occurrence probability and influence of the synoptic events are discussed. This research could help in understanding the onset of monsoon and its predictability for societal applications

Free-standing 2D gallium nitride for electronic, excitonic, spintronic, piezoelectric, thermoplastic, and 6G wireless communication applications

Abstract Two-dimensional gallium nitride (2D GaN) with a large direct bandgap of ~5.3 eV, a high melting temperature of ~2500 °C, and a large Young’s modulus ~20 GPa developed for miniaturized interactive electronic gadgets can function at high thermal and mechanical loading conditions. Having various electronic, optoelectronic, spintronic, energy storage devices and sensors in perspective and the robust nature of 2D GaN, it is highly imperative to explore new pathways for its synthesis. Moreover, free-standing sheets will be desirable for large-area applications. We report our discovery of the synthesis of free-standing 2D GaN atomic sheets employing sonochemical exfoliation and the modified Hummers method. Exfoliated 2D GaN atomic sheets exhibit hexagonal and striped phases with microscale lateral dimensions and excellent chemical phase purity, confirmed by Raman and X-ray photoelectron spectroscopy. 2D GaN is highly stable, as confirmed by TGA measurements. While photodiode, FET, spintronics, and SERS-based molecular sensing, IRS element in 6G wireless communication applications of 2D GaN have been demonstrated, its nanocomposite with PVDF exhibits an excellent thermoplastic and piezoelectric behavior

Assessments of population exposure to environmental pollutants using air quality measurements during Commonwealth Games-2010

During the "Commonwealth Games" 2010 (CWG-2010) in Delhi, the Indian government has implemented an ambitious project "System of Air quality Forecasting And Research (SAFAR)" for monitoring and forecasting air-quality scenario. Using high-precision spatio-temporal measurements of criteria pollutants from the SAFAR network, the number of cases are estimated for total, cardiovascular and respiratory mortalities and hospital admissions. In a thinly populated airport area, the excess number of cases for total mortality show ∼10 for PM2.5 and 25 for PM10, whereas, ∼110 for PM2.5 and ∼300 for PM10 in most populous Delhi University (DU) area. Cardiovascular mortality in airport area show ∼5 and <10 for PM2.5 and PM10, respectively, but, in DU area show ∼55 for PM2.5 and ∼140 for PM10. In DU locality, respiratory mortality shows ∼7 and ∼20 for PM2.5 and PM10 and, hospital admissions show ∼11 and ∼30 for PM2.5 and PM10, respectively. In airport area, excess cases of respiratory mortality and hospital admission tends to one for exposure to PM2.5 or PM10 levels indicating effective exposure is the key factor for health hazards. As public health gains, low air pollution levels were observed before the CWG due to effective washout by monsoonal rain and during CWG under policy-induced air quality measures could increase the life expectancy as against to post-CWG period. These results are important for the megacities in developing world as the SAFAR project is internationally recognized by the Global Urban Research Meteorology and Environment of the World Meteorological Organizatio