RNS Institute of Technology

A double-slope solar still (DSS) is considered one of the most promising techniques in desalination plants. However, the DSS has low productivity. In this study, the performance of a DSS has been enhanced by utilizing natural wick materials (bamboo, banana, and pineapple fibers) and nano-enhanced phase change materials (nano-PCM), which are made of graphene oxide (GO) and Glauber salt (GS). Among the three wick materials, the DSS with bamboo fiber and nano-PCM has the highest freshwater productivity of 3.41 L/day, compared to banana and pineapple fibers, which have 3.07 L/day and 2.86 L/day, respectively. In addition, the DSS with bamboo fiber has the highest energy efficiency of 44.33%, exergy efficiency of 2.61%, and evaporative heat transfer coefficient of 109.51 W/m2K. Furthermore, the economic analysis of the proposed system has shown that the cost of the distilled water produced by the DSS is $0.017, and the payback period is 5.2 months. In addition, the analysis has shown that the DSS has the highest sustainability index of 1.027 and CO2 mitigation potential of 10.15 tons.

The Phosphor Ba1-xMoO4:xEu(3+) (0.00 <= x < 0.09) prepared by low-cost solution combustion method were in a space group of I4(1)/a and crystalized in tetragonal phase. The intensity of photoluminescence was found to be maximum for the transition D-5(0)-> F-7(2) (615 nm) at an excitation wavelength of 394 nm with CIE color coordinates (0.6525, 0.3471) making it a potentially useful substance for red phosphor materials. Electrochemical impedance spectroscopy (EIS) research has demonstrated that the decreased charge transfer resistance of Ba1-xMoO4:xEu(3+) (0.00 <= x < 0.09) is responsible for their improved behaviour. When lithium was used as an analyte, Ba1-xMoO4:xEu(3+) (0.00 <= x < 0.09) demonstrated improved sensitivity in cyclic voltammetry studies at various scan rates. Further, the use of Ba1-xMoO4:xEu(3+) (x = 0.07) powder as a dusting agent in fingerprint applications suggest that nanophosphor-based techniques offer a promising advancement for non-destructive and high-resolution fingerprint imaging across diverse surfaces.

This study evaluates the corrosion inhibition performance of a newly synthesized organic compound, 2-amino4-methoxy-6-methyl (benzylidene) 1,3,5-triazine (AMMBT), which is non-toxic and exhibits medicinal relevance, for the protection of mild steel in 1 M hydrochloric acid (HCl) medium using both experimental and computational approaches. The inhibition efficiency of AMMBT was assessed through gravimetric analysis and electrochemical techniques, including potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The results show that inhibition efficiency increases with concentration, reaching a maximum of 89% at 100 mu M. Polarization studies indicate that AMMBT behaves as a mixed-type inhibitor. Temperature-dependent studies (303-333 K) reveal that adsorption follows the Langmuir isotherm and proceeds via an exothermic process. Surface characterization using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) confirms the formation of a protective adsorbed film on the mild steel surface. Density functional theory (DFT) calculations suggest that both neutral and protonated forms of AMMBT interact strongly with the metal surface through lone pair electrons on heteroatoms (N and O) and it-electrons of the conjugated system.

This investigation reports on the application of 5-amino-1,3,4-thiadiazole(4-nitro-benzylidine)-2-thiol (ATNBT) as a corrosion inhibitor for mild steel (MS) in 1 M hydrochloric acid. ATNBT exhibits significant protective action in acidic environments owing to its dissolution in water. The pursuit of highly efficient inhibitors remains a key objective in corrosion science to protect the metallic structures. The inhibition performance was assessed using electrochemical impedance spectroscopy and potentiodynamic polarization techniques. Experimental results revealed that inhibition efficiency increased with inhibitor dosage, with a maximum of 96.4% at 90 mu M. Potentiodynamic polarization confirmed ATNBT as a mixed-type inhibitor, and the adsorption process was consistent with the Langmuir adsorption isotherm. The activation energy () in the absence of the inhibitor was found to be 42.06 kJ mol 1 , whereas it increased to 103.01 kJ mol 1 in the presence of ATNBT. The changes in the surface morphology of mild steel and the chemical interactions between the inhibitor molecules and the specimen surface were examined using scanning electron microscopy (SEM). The mechanism of ATNBT's inhibition action was explored in greater detail through quantum chemical analysis. The Fukui index values indicated that the active sites are predominantly located on the heteroatoms (sulfur and nitrogen) of the molecule.

A new picrate salt of nitrogen-rich 4-(2-aminomethyl)pyridinium (PA_4AP) has been successfully crystallized in 2:1 stoichiometry confirming the acid-base proton-transfer. The crystal lattice is marked by H-bond and it-stacking interactions leading to a supramolecular architecture where picrate anions are sandwiched in between the 4-(2-aminomethyl)pyridinium (4AP) cations. Characterization techniques like elemental analysis, PXRD, UVvis, FT-IR, ESI-MS and 1H/13C-NMR spectroscopy have proved the crystallinity and purity of the complex salt. Then, nonlinear optical (NLO) properties of picric acid (HPA) and PA_4AP has been investigated in DMF solution by irradiating 532 nm Q-switched Nd:YAG nanosecond laser. The open aperture Z-scan curves indicate nonlinear absorption (NLA) behaviour in both the samples. The normalized transmittance (NT) dropped from 100% to 84% and 78% in PA and PA_4AP, respectively, indicating optical limiting (OL) response from both the samples. The NLA coefficient, ss (1.5 x 10- 11 m/W) and OL threshold (1.5 x 1013 W/m2) of PA_4AP was found to be higher than the values of HPA, suggesting hydrogen-bonding mediated NLO behaviour marked by reverse saturable absorption mechanisms. DFT calculations performed on optimized HPA and PA_4AP structures in comparison to the crystallographic structure of PA_4AP theoretically predict the smallest HOMO-LUMO gap (1.574 eV), the highest electrophilicity (19.203 eV), and the lowest chemical hardness (0.787 eV) for the crystallographic PA_4AP species compared to the other systems. The experimental results confirm the superior third-order NLO performance of the PA_4AP material driven by hydrogen bond interactions in the supramolecular scaffold.