Electrochemical behavior of nanocrystalline Ni–P alloys containing tin and tungsten

Autocatalytic ternary Ni-Sn-P, Ni-W-P and quaternary Ni-W-Sn-P films were prepared using an alkaline bath. Plain Ni-P films were also prepared for comparison. Corrosion resistance of the films was evaluated in 3.5% sodium chloride solution in non-deaerated condition by potentiodynamic polarization and electrochemical impedance spectroscopy methods. Deposits were also immersed in 3.5% sodium chloride solution for 7 days. All the coatings attained stable equilibrium potential within 30 minutes in NaCl medium. Lower corrosion current density values were obtained for ternary Ni-Sn-P coatings compared to the plain Ni-P coatings. Ternary Ni-W-P and quaternary Ni-W-Sn-P alloys did not show improved corrosion resistance compared to the ternary Ni-Sn-P coatings. Similar behavior of these coatings was further confirmed by the electrochemical impedance studies. After the potentiodynamic polarization test deposits were examined by scanning electron microscope. It was found that more corrosion occurred for the quaternary deposit compared to other deposits. Energy dispersive analysis of X-ray results indicated that more amount of Fe present on NiWP and NiWSnP coated samples. Similar behavior was confirmed from the optical images of the surfaces obtained for the deposits after the immersion test. The article is published in the original.     

Enhancing energy storage efficiency of lithiated carbon nitride (C7N6) monolayers under co-adsorption of H2 and CH4

There is a great interest in the design of innovative concepts and strategies of nitrogen rich carboneous materials for exploring their hydrogen (H₂) storage properties. Methane (CH₄) storage can be an alternative to H₂ because the combustion energy of the former is around three times higher than the latter. However, strong inter-molecular repulsion between the CH₄ molecules is a major bottleneck to achieve a high gravimetric density. In this study, we use first principles density functional calculations to investigate the coadoption of H₂ and CH₄ on Li decorated carbon nitride (Li–C₇N₆) monolayer. The repulsion between CH₄ molecules has been avoided by keeping them in asymmetric configuration whereas the repulsion between CH₄–H₂ is in moderation due to the exploitation of open Li doped sites on C₇N₆ surface. Though Li–C₇N₆ has a lower H₂ or CH₄ storage capacity due to weak van der Waals interactions, the capacity could be doubled with a novel strategy of co-mixing of H₂ with CH₄ which results into a significantly high gravimetric density of 8.1 wt%. This clearly shows that the CH₄–H₂ co-mixing strategies have the potential to further propel the prospects of C₇N₆ monolayers for reversible clean energy storage applications.     

海马齿对土壤的植物修复（1）：制革废水污染的土壤中Na^＋和Cl^-的去除

盐生植物海马齿（S．Portulacastrum）具有良好的耐盐能力，能够吸收氯化钠。本文研究了将海马齿作为生物累积体，用于吸收制革废水中存在的NaCl^-的可行性。将海马齿栽培在土壤中，用含不同浓度NaCl^-的制革废水进行灌溉，记录其生长参数，如根和枝的长度，并测定海马齿的叶和枝中累积的Na^＋和CF离子含量。结果表明，Na^＋和CF的累积量随着栽培密度和制革废水中盐浓度的增大而增加。但是，盐浓度的增加会导致海马齿生长减缓。在高栽培密度条件下，用含15000ppmNaCl的制革废水灌溉海马齿，Na^＋和Cl^-的吸收率可以分别达到34％和22％。与根和茎相比，海马齿叶子中Na^＋和Cl^-累积量最大。本文的研究结果说明．海马齿用于氯化钠的生物累积是可行的。     

Synthesis and properties of electrodeposited Ni/ceria nanocomposite coatings

Composite plating is a method of co-depositing fine particles of metallic or non-metallic compounds or polymers in the plated layer to improve material properties such as lubrication, wear resistance and corrosion resistance. In the present study, Ni was chosen as the matrix material and ceria nanoparticles were chosen as the distributed phase. Nanocrystalline ceria powder was synthesized by the solution combustion process and characterized by powder X-ray diffractometry (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The nanosize ceria particles were co-deposited with nickel from a nickel sulfamate bath using conventional electrodeposition method. The electrodeposition was carried out at current densities of 0.23, 0.77, 1.55, 3.1 and 5.4 A/dm². The microhardness of the Ni matrix was enhanced by the incorporation of ceria particles. Potentiodynamic polarization, electrochemical impedance spectroscopy and SEM were used to characterize the corrosion behaviour of Ni and Ni/CeO₂ coatings. These studies showed improved corrosion resistance for Ni/CeO₂ when compared to Ni. The microhardness, corrosion resistance and wear resistance of Ni and Ni/CeO₂ were compared.     

Role of conducting carbon in electrodes for electric double layer capacitors

Six electrodes with a varying amount (5, 10, and 15 wt.%) of conducting carbon nanotubes (CNT) and carbon nanofibers (CNF) were fabricated and their performance evaluated against a control sample that was devoid of any conducting material. The goal of this work was to determine the correlation between electrode conductivity and capacitance in 1 M tetraethyl ammonium tetrafluoroborate (TEABF₄) in propylene carbonate (PC) electrolyte. CNT electrodes exhibit the lowest electrical resistance, while CNF electrodes had the highest capacitance. The specific capacitance (120-140 F/g) increased monotonically up to 2.5 V. An inverse correlation between electrical resistance and capacitance was observed for various concentrations. The electrodes were characterized using CV, EIS, SEM, and BET analysis.     

Optimal data collection design in machine learning: the case of the fixed effects generalized least squares panel data model

Machine Learning - This work belongs to the strand of literature that combines machine learning, optimization, and econometrics. The aim is to optimize the data collection process in a specific...     

Preparation,characterization, and in vitro bioactivity of Bixa orellana extract-impregnated collagen microspheres

Collagen microspheres usually have particle size lesser than 200 µm, which are characteristically free-flowing powders of protein. They can overcome some of the conventional therapy problems and enhance therapeutic efficacy due to their biocompatible and biodegradable nature. Collagen microspheres were prepared using the fish Lates calcarifer scale collagen and were loaded with Bixa orellana plant extract. The Bixa orellana plant extract-loaded collagen microsphere was characterized for its physico-chemical properties using Fourier-transform infrared, Raman spectra, X-ray diffraction, scanning electron microscopy, and particle size analysis, and in vitro plant extract release. This plant extract showed good antimicrobial property against Staphylococcus aureus and Escherichia coli. The in vitro anticancer activity of the prepared material was carried out using MCF-7 cell lines which showed 83.46 % of cell death at 1000 µg/well. Anticancer effect of the prepared material can be enhanced by increasing the concentration of plant extract in the composite.     

Influence of spinning parameters on synthesis of alumina fibres by centrifugal spinning

The present study investigates the synthesis of alumina fibres of 5–15?µm dia. by sol-gel process through centrifugal spinning. Among various spinning parameters such as rpm, viscosity, humidity, chamber temperature etc., effect of rpm and viscosity on quality of spun fibres was examined in order to spin less defective (less shots) fibres. From the rpm vs viscosity experiments, it was concluded that viscosity between 13 and 42?Pa.s with 3000?rpm was favourable for obtaining fibres containing less shots. It was shown that besides viscosity, refractive index and percent weight loss of the aged sol can be used as indicator for determining spinnability of alumina precursor sols. Influence of only preheating and continuous heating of the chamber during spinning were also investigated and it was found that only preheating did not help in producing fibres. Besides this, influence of hot air blower (HAB) aligned in different directions with respect to the spinnerette, on fibre quality was tested. It was observed that the quality of fibres did not change due to change in HAB direction.     

PEM fuel cell supported distribution static compensator for power quality enhancement in three-phase four-wire distribution system

One of the major problems in electrical power system is the lack of quality of power due to the rapid growth of nonlinear load and unbalanced load utilization in three-phase four-wire distribution system. In this paper, PEM (Proton Exchange Membrane) fuel cell supported four-leg Distribution Static Compensator (DSTATCOM) is modelled to mitigate harmonics, neutral current and load balancing under nonlinear load and unbalanced load conditions in three-phase four-wire distribution system. The instantaneous reactive power (IRP) theory control algorithm is proposed for four-leg DSTATCOM. The Real coded Genetic Algorithm (RGA) optimized Proportional Integral (PI) controller and Adaptive Neuro Fuzzy Inference System (ANFIS) controller are used for regulating the DC link voltage of DSTATCOM. This paper also investigates the performance of ANFIS based DSTATCOM with conventional method. The proposed system is modelled and its performance is analyzed in MATLAB/SIMULINK.