Optical and dielectric properties of divalent copper based double perovskite compound, Gd2CuTiO6.

In this work, we have investigated high temperature dielectric properties and room temperature optical properties on rare earth ion based orthorhombic Gd2CuTiO6(GCTO). Optical properties like reflectance and band gap were determined from ultra-violet visible (UV-Vis) diffuse reflectance spectroscopy technique and photoluminescence (PL) spectrum. The compound exhibited substantial optical absorption and emission in the visible region. Our findings reveal the presence of an intermediate band, as evidenced by the difference between the band gap values obtained from the Tauc plot using the diffuse reflectance spectrum (3.07 eV) and the PL spectrum (2.4 eV). Furthermore, thermogravimetric analysis demonstrated high thermal stability with <0.4% change in mass over a wide temperature range of 30 °C-1200 °C in air environment. Moreover, lead-halide free compound, GCTO is highly thermally stable oxide double perovskite with wide band gap and absorption in the UV-Vis range are highly suitable for optical applications In addition, dielectric properties of the compound have been examined using impedance spectroscopy as a function of frequency ranging from 500 Hz to 1 MHz and temperature between 300 K and 550 K. Compounds with relaxor behaviour at high temperatures and high thermal stability are desired for several applications. Because of the cation disorders present in this compound, GCTO displays dielectric relaxor behaviour indicative of a distribution of relaxation times. Furthermore, the frequency-dependent modulus illustrated a thermally activated conduction mechanism. Cole-Cole plots of electrical modulus suggest prominent grain contribution above 350 K.

Examining the role of perceived stress on learning satisfaction under the influence of academic burnout in the post-COVID world.

BACKGROUND: In the last two years, due to the impact of COVID-19, students were forced to continue their education online because the government imposed restrictions to limit the spread of the virus. However, with the resumption of offline classes, the students seem to be suffering more from stress and isolation as they must face the challenges of the real world, which are quite different from the virtual one to which they have become accustomed. In this study, the effect of stress on students leading to their academic burnout and the influence of burnout on their learning satisfaction was studied. MATERIALS AND METHODS: The data were collected from 343 students of final year postgraduation courses in business management studies in India. The collected data were subject to analysis using PLS-SEM through SmartPLS 4.0 software. RESULT: The results of the study state that the perceived stress significantly increases cynicism, and exhaustion with a coefficient value of 0.481 each and decreases self-efficacy with - 0.03. Additionally, exhaustion acts as a mediator that decreases the effect of perceived stress over learning satisfaction with a positive indirect effect of 0.176. CONCLUSION: The study concludes that not all types of stress are bad for students; hence, increasing perceived stress leads to increased learning satisfaction. Whereas, in the presence of burnout factors, such as exhaustion and cynicism, learning satisfaction decrease. However, self-inefficacy, one of the factors under burnout, doesn't show any effect on learning satisfaction. The present study is widely applicable to industry and academia to deal with burnout to improve students learning satisfaction.

Black carbon derived PET plastic bottle waste and rice straw for sorption of Acid Red 27 dye: Machine learning approaches, kinetics, isotherm and thermodynamic studies.

This study focuses on the probable use of PET waste black carbon (PETWBC) and rice straw black carbon (RSBC) as an adsorbent for Acid Red 27 (AR 27) adsorption. The prepared adsorbent is characterized by FE-SEM and FT-IR. Batch adsorption experiments were conducted with the influencing of different operational conditions namely time of contact (1-180 min), AR 27 concentration (5-70 mg/L), adsorbent dose (0.5-20 g/L), pH (2-10), and temperature (25-60°C). High coefficient value [PETWBC (R2 = 0.94), and RSBC (R2 = 0.97)] of process optimization model suggesting that this model was significant, where pH and adsorbent dose expressively stimulus removal efficiency including 99.88, and 99.89% for PETWBC, and RSBC at pH (2). Furthermore, the machine learning approaches (ANN and BB-RSM) revealed a good association between the tested and projected value. Pseudo-second-order was the well-suited kinetics, where Freundlich isotherm could explain better equilibrium adsorption data. Thermodynamic study shows AR 27 adsorption is favourable, endothermic, and spontaneous. Environmental friendliness properties are confirmed by desorption studies and satisfactory results also attain from real wastewater experiments. Finally, this study indicates that PETWBC and RSBC could be potential candidates for the adsorption of AR 27 from wastewater.

Improvisation of salinity stress response in mung bean through solid matrix priming with normal and nano-sized chitosan.

Nano particles open up a new avenue in crop science because of their unique physicochemical properties. Chitosan is preferred as priming agent in nano-form due to its biodegradability and non toxicity. Prepared nano-chitosan was characterized by Dynamic light scattering study, Fourier-transform infrared spectroscopy study and scanning electron microscopy. In present study the morphological, physiological and biochemical responses with an emphasis on several oxidative stress markers like proline, malondialdehyde (MDA), hydrogen peroxide (H2O2) contents of mung bean seedlings to 0, 4 and 8 dS/m salt stress conditions after Solid Matrix Priming (SMP) using the elicitors like nano-chitosan, chitosan and water were studied. The activities of different antioxidant enzymes like superoxide dismutase, catalase and oxidative stress markers like proline, H2O2 and MDA increased considerably over water control in accordance with salt stress gradient. However, SMP with nano-chitosan showed significant improvement showing reduction in H2O2 and MDA contents over control leading to the better growth, increased chlorophyll content and metabolism. Thus, our study shows that SMP with both normal and nano sized chitosan will be able to overcome the adverse effect of salt stress in mung bean seedlings allowing the activation of their defense mechanisms for better protection against salt stress.

Studies on neutron spectrum characterization for the Pneumatic Fast Transfer System (PFTS) of KAMINI reactor.

Characterization of neutron energy spectrum along with the determination of sub-cadmium to epithermal neutron flux ratio (f) and the epithermal neutron flux shape factor (α) has been carried out at pneumatic fast transfer system (PFTS) of KAMINI reactor. The facility has been extensively used for the neutron activation analysis (NAA) studies using both k0-NAA and relative method. This paper describes the multi-foil activation method to determine the reaction rates followed by the generation of computed guess spectrum to unfold the neutron spectrum using least square minimization approach.

Determination of neutron energy spectrum at KAMINI shielding experiment location.

The neutron spectrum at KAMINI reactor south beam tube end has been determined using multifoil activation method. This beam tube is being used for characterizing neutron attenuation of novel shield materials. Starting from a computed guess spectrum, the spectrum adjustment/unfolding procedure makes use of minimization of a modified constraint function representing (a) least squared deviations between the measured and calculated reaction rates, (b) a measure of sharp fluctuations in the adjusted spectrum and (c) the square of the deviation of adjusted spectrum from the guess spectrum. The adjusted/unfolded spectrum predicts the reaction rates accurately. The results of this new procedure are compared with those of widely used SAND-II code.