Distribution of uranium in groundwaters of Bathinda and Mansa districts of Punjab,India: inferences from an isotope hydrochemical study

This paper presents the isotope hydrochemical results of groundwaters from southwest Punjab for assessing the uranium contamination and evaluating the factors leading to elevated uranium concentration. A total of 35 samples covering shallow and deep zones were collected for hydrochemistry and isotopes. Uranium concentration ranges between 2.3 and 357 µg L^?1 and 66% of the samples are contaminated. Both shallow and deep zones show U contamination but high incidences are noticed in shallow zone. Hydrochemical correlations infer geological sources rather than anthropogenic sources responsible for U contamination. Isotopically there is no clear distinction between high and low U groundwater.     

Effects of periodic masker interruption on the intelligibility of interrupted speech

When listeners hear a target signal in the presence of competing sounds, they are quite good at extracting information at instances when the local signal-to-noise ratio of the target is most favorable. Previous research suggests that listeners can easily understand a periodically interrupted target when it is interleaved with noise. It is not clear if this ability extends to the case where an interrupted target is alternated with a speech masker rather than noise. This study examined speech intelligibility in the presence of noise or speech maskers, which were either continuous or interrupted at one of six rates between 4 and 128 Hz. Results indicated that with noise maskers, listeners performed significantly better with interrupted, rather than continuous maskers. With speech maskers, however, performance was better in continuous, rather than interrupted masker conditions. Presumably the listeners used continuity as a cue to distinguish the continuous masker from the interrupted target. Intelligibility in the interrupted masker condition was improved by introducing a pitch difference between the target and speech masker. These results highlight the role that target-masker differences in continuity and pitch play in the segregation of competing speech signals.     

A fourth‐order H1‐Galerkin mixed finite element method for Kuramoto–Sivashinsky equation

A H¹‐Galerkin mixed finite element method is applied to the Kuramoto–Sivashinsky equation by using a splitting technique, which results in a coupled system. The method described in this article may also be considered as a Petrov–Galerkin method with cubic spline space as trial space and piecewise linear space as test space, since the second derivative of a cubic spline is a linear spline. Optimal‐order error estimates are obtained without any restriction on the mesh for both semi‐discrete and fully discrete schemes. The advantage of this method over that presented in Manickam et al., Comput. Math. Appl. vol. 35(6) (1998) pp. 5–25; for the same problem is that the size (i.e., (n + 1) × (n + 1)) of each resulting linear system is less than half of the size of the linear system of the earlier method, where n is the number of subintervals in the partition. Further, there is a requirement of less regularity on exact solution in this method. The results are validated with numerical examples. Finally, instability behavior of the solution is numerically captured with this method.     

Enhanced ionic conductivity in La3+ and Sr2+ co-doped ceria: carbonate nanocomposite

Ionics - A series of ceria-based nanocomposites consisting of Ce0.85La0.125Sr0.025O1.9125 (LSCO) and binary carbonate mixture Li2CO3–Na2CO3 (LNCO) have been prepared as functional...     

Microwave‐Assisted Copper‐Catalyzed Oxidative Cyclization of Acrylamides with Non‐Activated Ketones

An operationally simple and efficient microwave‐assisted protocol for the oxidative cyclization of acrylamide derivatives with non‐activated ketones to generate 3,3‐disubstituted oxindoles is described. The reaction proceeds by a copper‐catalyzed tandem radical addition/cyclization strategy and tolerates a series of functional groups with moderate to excellent yields.     

Evaluating hydrogen-bond propensity,hydrogen-bond coordination and hydrogen-bond energy as tools for predicting the outcome of attempted co-crystallisations

ABSTRACT

Two different structure-informatics based methods and one approach based on hydrogen-bond interaction energies were evaluated for their abilities to predict the experimental outcomes of attempted co-crystallisations between two known drug molecules, Nevirapine and Diclofenac, and a series of potential co-formers. The hydrogen-bond propensity (HBP) tool gave the correct result in 26 out of 30 cases, whereas a hydrogen-bond coordination (HBC) method predicted the correct outcome in 22 out of 30 cases. Finally, calculated hydrogen-bond energies (HBE) using a simple electrostatic model, gave the correct result in 23 out of 30 experiments. In those cases, where the crystal structure of a co-crystal of either Nevirapine or Diclofenac was known, we also examined how well the three methods predicted which primary hydrogen-bond interactions were present in the crystal structure. HBP correctly predicted 6 out of 6 cases, HBC could not predict any of the synthon formations correctly, and HBE successfully predicted 1 out of 6 cases.     

Oxidation of benzyl alcohol by Cr<Superscript>VI</Superscript> supported on Ambersep 900 (O<Superscript>−</Superscript>H) – a kinetic and mechanistic investigation

The oxidation of benzyl alcohol was found to proceed through ester formation. In a slow step the ester decomposes and produces chromium(IV). Chromium(IV) formed in a slow step, oxidizes another molecule of benzyl alcohol because our oxidant was supported on polymeric material and generates a free radical in a fast step. The free radical subsequently reacts with another oxidant site in a polymeric reagent in a fast step and forms chromium(V). In a last step the intermediate chromium(V) reacts with benzyl alcohol to produce benzaldehyde. The mechanism was predicted and activation parameters were also determined.     

Stearate as a green corrosion inhibitor of magnesium alloy ZE41 in sulfate medium

The efficiency of stearate as a corrosion inhibitor for magnesium alloy ZE41 has been studied in sodium sulfate medium, employing electrochemical techniques like potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The results of polarization study imply that stearate functions as a mixed-type corrosion inhibitor with a predominant anodic control. The adsorption of stearate on alloy surface is found to obey the Langmuir adsorption isotherm. The proposed inhibition mechanism involved adsorption of stearate onto metal surface, followed by precipitation of magnesium stearate within the microdefects of Mg(OH)₂ surface film which enhanced the barrier effect of an otherwise porous partially protective film.     

Radiological and hydrological implications of dissolved radon in alluvial aquifers of western India

Journal of Radioanalytical and Nuclear Chemistry - A study was undertaken to measure the dissolved radon (222Rn) concentration in parts of western India (Southwest Punjab) in order to evaluate its...     

Hierarchical Nanoflower Arrays of Co9S8-Ni3S2 on Nickel Foam: A Highly Efficient Binder-Free Electrocatalyst for Overall Water Splitting

Hydrogen production is vital for meeting future energy demands and managing environmental sustainability. Electrolysis of water is considered as the suitable method for H₂ generation in a carbon-free pathway. Herein, the synthesis of highly efficient Co₉S₈-Ni₃S₂ based hierarchical nanoflower arrays on nickel foam (NF) is explored through the one-pot hydrothermal method (Co₉S₈-Ni₃S₂/NF) for overall water splitting applications. The nanoflower arrays are self-supported on the NF without any binder, possessing the required porosity and structural characteristics. The obtained Co₉S₈-Ni₃S₂/NF displays high hydrogen evolution reaction (HER), as well as oxygen evolution reaction (OER), activities in 1 m KOH solution. The overpotentials exhibited by this system at 25 mA cm⁻² are nearly 277 and 102 mV for HER and OER, respectively, in 1 m KOH solution. Subsequently, the overall water splitting was performed in 1 m KOH solution by employing Co₉S₈-Ni₃S₂/NF as both the anode and cathode, where the system required only 1.49, 1.60, and 1.69 V to deliver the current densities of 10, 25, and 50 mA cm⁻², respectively. Comparison of the activity of Co₉S₈-Ni₃S₂/NF with the state-of-the-art Pt/C and RuO₂ coated on NF displays an enhanced performance for Co₉S₈-Ni₃S₂/NF both in the half-cell as well as in the full cell, emphasizing the significance of the present work. The post analysis of the material after water electrolysis confirms that the surface Co(OH)₂ formed during the course of the reaction serves as the favorable active sites. Overall, the activity modulation achieved in the present case is attributed to the presence of the open-pore morphology of the as formed nanoflowers of Co₉S₈-Ni₃S₂ on NF and the simultaneous presence of the surface Co(OH)₂ along with the highly conducting Co₉S₈-Ni₃S₂ core, which facilitates the adsorption of the reactants and subsequently its conversion into the gaseous products during water electrolysis.