Efficient water splitting electrolysis on a platinum-free tungsten carbide electrocatalyst in molten CsH2PO4 at 350–390 °C

Tungsten carbide is investigated as cathode in the electrocatalytic water splitting in molten CsH₂PO₄ in the medium temperature range from 350 to 390 °C. The electrocatalytic activity of tungsten carbide improves with increasing temperature and at 390 °C surpasses that of platinum. Hydrogen is formed during the electrolysis as confirmed by Raman spectroscopy. The tungsten carbide coating of the electrode is stable during electrolysis for at least 63 min at 350 °C and undergoes no apparent change even at 390 °C. The use of molten CsH₂PO₄ as electrolyte in the medium temperature range allows for the development of abundant and cheap catalysts for the electrochemical water splitting.     

Synthesis and characterization of HoVO4/CuO nanocomposites for photodegradation of methyl violet

The extension of new materials with a high percentage of dye degradation is one of the significant challenges in photocatalytic degradation of contaminants in water sources. The goal of this work is to illuminate the feasibility of methyl violet dye photodegradation using the HoVO₄/CuO heterostructures as new photocatalytic materials under UV/visible-light irradiation. Different parameters influencing the morphology of nanostructures have been examined, including the use of various organic acids and their ratios, as well as the adjustment of diol. The data for the initial characterization of nanopowders were collected through XRD, FT-IR, SEM, TEM, and DRS analyses. The optimal HoVO₄ sample in the presence of malonic acid and polyethylene glycol (PEG) with a molar ratio of 2.5:4, with the mean particle size of 21 nm, as well as the optimal HoVO₄/CuO nanocomposite sample in the presence of malonic acid and PEG with the mean particle size of 38 nm, were detected by SEM analysis. The photodegradation rate was 71% and 86%, respectively, using HoVO₄ and HoVO₄/CuO samples. The photocatalytic degradation of methyl violet dye under UV and visible light illustration indicates that, compared to pristine HoVO₄ nanostructures, the use of HoVO₄/CuO heterostructure leads to increased dye degradation ability. The results of recent research show that the HoVO₄/CuO nanocomposite can be synthesized by a simple Pechini process and has a high photocatalytic degradation efficiency.     

Subset simulation method including fitness-based seed selection for reliability analysis

Probability estimation of rare events is a challenging task in the reliability theory. Subset simulation (SS) is a robust simulation technique that transforms a rare event into a sequence of multiple intermediate failure events with large probabilities and efficiently approximates the mentioned probability. Proper handling of a reliability problem by this method requires employing a suitable sampling approach to transmit samples toward the failure set. Markov Chain Monte Carlo (MCMC) is a suitable sampling approach that solves the SS transition phase using the failed sample of each simulation level as the seed of next samples. This paper is aimed to study the seed selection effect on the SS accuracy through several seed selection approaches inspired by the genetic algorithm and particle filter and using the main PDF of the variables to assign a mass function probability to each subset sample in the failure domain. Roulette wheel (I, II), tournament and proportional probability techniques are then employed to choose the weighed samples as seeds to be placed in the MCMC to transmit the samples. To examine the capability of each approach, reliabilities of some engineering problems were investigated and results showed that the proposed approaches could find proper failure sets better than the original SS method, especially in problems with several failure domains.

     

Inhibition of aluminum corrosion in acid solution by environmentally friendly antibacterial corrosion inhibitors: Experimental and theoretical investigations

Protection of Metals and Physical Chemistry of Surfaces - The inhibition performance of penicillin G(I), methicillin(II) and nafcillin(III) on the corrosion of aluminum in a 1 M HCl solution has...     

Tubular ceramic performance as separator for microbial fuel cell: A review

The depletion of unsustainable conventional energy sources and global warming issues create world demand for green energy sources. The microbial fuel cell (MFC) technology with the capability to convert environmental waste to energy can be improved with cheap ceramic material. The ceramic is structurally porous, thus allow a direct exchange of cation. The ceramic material also enhances stability thermally and chemically, non-ion selective characteristic, high mechanical strength, and easily washable. Commercially produced ceramic structures have been proven to reduce Chemical Oxygen Demand up to 92% and allow high power output. It is also comparatively durable in the long-term operation of MFC, compared to the commercially available membrane. The novelty of using tubular design is the efficient use of space, which leads to the possibility of scaling up. As a conclusion, a combination of both ceramic material and tubular design could be an excellent alternative separator for MFC.     

Solar absorptivity of nano-porous anodic alumina (NPAA): effects of structural features

Great structural and geometrical characteristics of nano-porous anodic alumina (NPAA) would subject these type materials to a wide application in different fields of science and technology. Effect of anodizing parameters on structural features of NPAA has been the topic of a large number of studies. Nevertheless, the relation of NPAA characteristics with its optical properties has rarely been addressed. This paper investigates the effect of film thickness, beams incident angle, and average diameter, area percentage, and direction of pores on solar absorptivity. The results showed that, increasing of the film thickness, decreasing of the average pores’ diameter, and distortion of pores enhanced the solar absorptivity. Furthermore, at an optimum value of pores’ area percentage the absorptivity had a maximum value. Finally, increasing of the incident angle enhanced the solar absorptivity.     

Investigating the performance of a water-based photovoltaic/thermal (PV/T) collector in laminar and turbulent flow regime

The objective of this work is to simulate a water-based flat plate photovoltaic/thermal system with glass cover and without it in laminar and turbulent regime and investigating the effects of solar irradiation, packing factor, Reynolds number, collector length, pipes diameter and number of pipes on the performance of this system. The accuracy of the model has been validated with the available data in the literature, where good agreements between the results have been achieved. The results showed that the energy efficiency in the glazed photovoltaic/thermal system is higher than unglazed one, while its exergy efficiency depends on the packing factor, Reynolds number and collector length. The results also indicated that increasing of solar radiation and packing factor increases total energy and exergy efficiency in both laminar and turbulent regime. Besides, it was found that there are the optimum values for mass flow rate and number of pipes that maximize exergy efficiency. The value of the optimum mass flow rate is larger in the case of unglazed system compared to that of glazed one. Furthermore, in most cases, the total energy efficiency in turbulent regime is higher, whereas the total exergy efficiency in laminar regime is superior.     

Hydraulic design,technical challenges and comparison of alternative configurations of a four-product dividing wall column

This study addresses technical feasibility related aspects of multi-partition wall alternatives for a four-product dividing wall column, which, although highly beneficial, have not been yet attempted in industrial practice. Utilizing an industrially relevant aromatics processing plant case as basis for design and evaluation of cost-effectiveness of alternative configurations, this paper focuses on the hydraulic design and dimensioning of a minimum energy configuration with two overhead product streams. DWC technology related issues are discussed, which can help to distinguish what makes sense and what not when dealing with practical implementation of multi-partition wall configurations.     

The synthesis,structure and photoluminescent properties of solid-state green to yellow emitters based on β-carboline

A series of solid-state green to yellow emitters based on β-carboline core were synthesized and characterized. The crystal structures of four of them were determined by single crystal X-ray diffraction analysis. The photoluminescent properties of β-carbolines were examined in solution and in the solid state. It was found that these fluorophores were luminescent, having solid-state emission at wavelengths ranging from 505 to 582 nm, depending on structure. Significantly, two naphthalene-carboline hybrids exhibit strong green fluorescence emission both in solution and in crystalline state. However, two methoxyl-phenyl substituted β-carboline derivative show intense green/yellow emission peaked at 540–582 nm, and display red-shifted by 40–82 nm with respect to the solution behavior. The experimental results demonstrated that the solid-state emission ranging from green to yellow can be readily tuned by simply varying molecular structure. The solid-state luminescent properties are highly dependent on the nature and position of the substituents and also on the molecular arrangements and the intermolecular interactions.