Structure and stability of Pb-Sb liquid alloys

This investigation reports the structure and stability of liquid lead-antimony alloys determined with the help of the Kumar-Samarin technique of centrifuging liquid metals. It shows that liquid lead-antimony alloys in the composition ranges 0 to 35 and 65 to 100 at. % antimony are stable and can be regarded as a colloidal dispersion of lead- and antimony-rich clusters in monatomic matrices; the cluster size is minimum at the eutectic composition. The paper suggests that solutions in the intermediate composition range corresponding to the inflection in the liquidus curve are incipiently immiscible and shows that they can be separated into conjugate phases.     

Predicting and optimizing the heat transfer performance of radiator with functionalized graphene nanofluids

Accurately predicting the heat transfer characteristics of coolants used in thermal management of energy systems like heat exchangers, power electronics, and heating, ventilation, and air conditioning is indispensable in maintaining its operating conditions within safety limits. Apart from safety, factors such as power consumption and operating cost are the most important constraints to be considered in designing an energy-efficient and cost-effective cooling solution. In this study, the experimental data available from previous research on the use of functionalized graphene-based nanofluids in compact heat exchangers such as the automotive radiator is used to optimize the heat transfer performance parameters like Nusselt number of the nanofluid, the friction factor, and effectiveness of the heat exchanger. A supervised machine learning technique like the artificial neural network is used to obtain the objective functions of the response variables in terms of input features such as Reynolds number, Prandtl number, the volume concentration of nanoparticles in the base fluid, number of transfer units, heat capacity, the density of nanofluid, pressure drop and velocity. On the current dataset, it is found that by using the Bayesian regularization training algorithm and tangent sigmoidal activation function in the neural network, the best accuracies in the prediction can be achieved. Well-known nature-inspired optimization algorithms like genetic algorithms and simulated annealing are used in optimizing the above-mentioned response variables. Both algorithms converged to the same values of the objective functions. The optimum values of Nusselt number, effectiveness, and friction factor are 105.65, 0.506, and 0.0038, respectively, for the given composition of the nanofluid and radiator configuration.     

Silicon-silver dendritic nanostructures for the enhanced photoelectrochemical splitting of natural water

We report on the photoelectrochemical (PEC) splitting of natural water (pH 7) using silicon (Si) nanowires fitted with silver (Ag) dendrites (dendritic nanostructures) as working electrodes (photoanodes). A detailed study of the PEC water splitting process was carried out using linear sweep voltammetry, electrochemical impedance spectroscopy (EIS) and Mott-Schottky (M-S) measurements. The measured photocurrent density of 1.7 mA/cm² at an external voltage of ?0.6 V under white light illumination demonstrates the efficient decomposition of natural water using dendritic nanostructures as working electrodes. This decomposition is mainly attributed to a significant strengthening of the effective interface between working electrode surface/water and to a decline in the recombination of photoinduced carriers in the presence of Ag dendrites. We propose that the Schottky barrier between Si and Ag dendritic nanostructures favors enhanced photoinduced charge carrier separation. Photoinduced holes in Si are transferred to Ag dendrites (nano branches and leaves) that serve as a charge sink to effectively carry out the PEC oxidation of water. Photoinduced charge carrier separation enhancement was corroborated by the kinetics of our carrier recombination study. We obtained a reasonably long transient period of 80 s for the photoinduced carriers. EIS results show that the charge transfer resistance (150 Ω) of the dendritic nanostructure surface is low enough to promote interfacial charge transfer. This resistance generated a large carrier concentration of ～1.1 × 10²⁰ cm^?3 at the working electrode/water interface according to an M-S analysis. An applied bias-photon-to-current-conversion efficiency level of roughly 4% is reported, demonstrating the efficient PEC splitting of natural water.     

An assessment by subsistence farmers of the risks to food security attributable to climate change in Makwanpur,Nepal

The potential impacts of climate change on the food security of subsistence farmers is a serious concern. This article explores the food security situations of two categories of subsistence farm households, vegetable- and cereal-based farming systems, in the Makwanpur district of Nepal in the context of climate change. Local climate data for the past 30 years were analyzed. Interviews with local farmers and key informants, and focus group discussions were carried out to collect the primary data. Empirical data showed that changes in climate variables for the study period were in line with farmers’ perceptions and that farming communities were negatively impacted. Perceived impacts were erratic rainfall, increased frequency of floods and droughts, soil degradation and insect pests, weeds and diseases. Farmers have modified traditional cropping patterns and calendar, changed crop varieties and increased fertilizer and pesticide applications in order to maintain crop yields. They have also sought off-farm employment. However, agricultural productivity in the area is declining and only one third of all households in the area were food secure. Household food insecurity was at mild to moderate levels, but vegetable-based households were more secure than cereal-based ones. At the household level, locally successful adaptive measures, such as rainwater harvesting, mulching, planting date adjustments, off-farm opportunities, including infrastructure and extension support, could increase production and contribute to reversing the impact of increased risk attributed to climate change.     

Allergenic responses of red kidney bean (Phaseolus vulgaris cv chitra) polypeptides in BALB/c mice recognized by bronchial asthma and allergic rhinitis patients

Allergenicity potential of red kidney beans (Phaseolus vulgaris cv chitra) was assessed and attempts were made to identify the responsible proteins by pepsin digestibility assay and IgE immunoblotting. To evaluate allergenic potential, BALB/c mice were sensitized with red kidney bean proteins and levels of specific immunoglobulin, histamine, mast cell protease-1, cytokines and CCL-2 were measured. To confirm our findings in BALB/c, the studies were also extended to human subjects. Human sera collected from control subjects and allergic patients after skin prick test were used for IgE immunoblotting, measuring the levels of total and specific IgE and determining cross reactivity of red kidney bean with other legumes. Red kidney bean allergenic potential was evident by significant increase in specific IgE, IgG1, histamine, mast cell protease-1 and Th2 cytokine levels in comparison to control. Enhanced level of eosinophils in jejunum, prominent anaphylactic symptoms, and eruptive histopathological changes give indication towards red kidney beans allergenicity. IgE immunoblotting detected five protein components with molecular weights of approximately 170, 100, 43, 34 and 20 kDa. Red kidney bean proteins showed cross reactivity with peanut, soybean, chickpea and black gram. Finally, this work demonstrated that red kidney beans may induce allergic response in mice similar to human subjects, with identification of five clinically relevant allergenic protein components.