The impact of using Particle Swarm Optimisation on the operational characteristics of a stand-alone hydrogen system with on-site water production

In a previous paper, we analysed the impact of renewable energy intermittency on the operational characteristics of hydrogen energy systems with pre-set Power Management Strategies not subject to optimisation. The research presented in this follow-up paper extends that earlier work and demonstrates the validity of applying Particle Swarm Optimisation (PSO) to size and optimise hydrogen systems. Specifically, PSO is used to iteratively converge on the (short-term) battery capacity (Ah) and hydrogen storage (L) in addition to defining the switching parameters which a Power Management Strategy (PMS) uses. The PSO algorithm is guided by three operational objective functions and conducted using MATLAB/Simulink. Simulations also incorporate laboratory resolved device characteristics.     

Optimization of Gas Nozzles Geometry in Dual-Fuel Burners of Power Stations

Thermal power required by boilers in steam power stations is supplied through gas or heavy oil fueled burners. Incorrect functioning of these burners results, on one hand, in their inability to supply the utility’s needed steam and, on the other hand, in imposing damages to various parts of the boiler and burner’s structure itself. The present paper investigates problems related to the burners used in the boilers of Shazand 325 MW power station in Arak. Gas-fueled nozzles of these boilers had suffered burns, so that a large number of them would have to be either repaired or replaced in every six-monthly maintenance cycle. These difficulties are caused partly by design errors and partly by incorrect commissioning of these burners. In this paper, the burners’ faults are investigated from the following viewpoints: (1) Statistical assessment of failures. (2) Investigation of trend in the nozzles failure and microstructure changes during operations. (3) Calculation of nozzles temperature when using heavy oil and natural gas fuels. Investigations leading to solutions providing new designs for nozzles in this paper and later evaluation of temperature of the new nozzles in various conditions using natural gas and heavy oil fuels have been carried out.     

Inhibition of corrosion of α-brass (Cu-Zn, 67/33) in acid chloride solutions by some amino pyrazole derivatives

The inhibition of corrosion of commercial 67/33 brass in 0.1m HCl acid solutions by some amino pyrazole derivatives was tested using polarization, capacitance and weight-loss measurements. The amino pyrazole derivatives were 3(5)-amino, 5(3)-phenyl pyrazole; 3(5)-amino, 5(3)[4^--chlorophenyl] pyrazole; 3(5)-amino, 5(3)[4^--methoxy phenyl]pyrazole; 3(5)-amino, 5(3)[4^--methyl phenyl]pyrazole; 3(5)-amino, 5(3)-cyano pyrazole; and 3(5)-amino, 4-phenyl-5(3)-methyl pyrazole. The results showed that these compounds predominate as cathodic inhibitors and inhibition efficiencies up to 91% can be obtained. The inhibition was assumed to occur via chemisorption of the inhibitor molecules fitting a Temkin isotherm. The influence of the substituent group on the inhibition efficiency of the inhibitor was explained in terms of the density of the electron cloud on the pyrazole ring and the mode of adsorption. Although increase in temperature was found to decrease the corrosion in the absence of the inhibition, it increased in the presence of inhibitor, probably via desorption of the inhibitor molecules.     

Formability behavior of brass alloy sheet: the role of twins in microstructure

Quantitative understanding of the process and formability parameters involved in grain size and the formation of annealing twins after plastic straining is important in the control of the manufacturing process. There is a synergistic effect of strain and temperature on the density of annealing twins. Formability of brass alloy sheets was studied after annealing of 65% cold worked (CW) samples at different temperatures (300–600°C). Tensile, deep drawing and Erichsen tests were carried out at room temperature to evaluate formability of alloy. Effect of annealing temperature on density, distribution and size of twins is investigated. It was shown that annealing of brass alloy resulting in formation of annealing twins which at higher annealing temperature were reduced by increasing grain size. Best deep drawability would be achieved by annealing at moderate temperature 400–450°C which microstructure consists of fine grain and twin bands. Work hardening exponent of samples was calculated based on the tensile test data and correlated with stretch ability of annealed brass sheets. It was found that the sheets annealed at 600°C possess best ductility and high average n-value.     

Development of new and modified numerical methods for hyperbolic conservation laws

Abstract

The aim of the present work is to propose and modify several numerical methods including the classes of temporal discretization methods for hyperbolic conservation laws. The first order in space standard Lax approximation is updated to modified first-order and newly proposed third-order accurate approximation. Presently proposed methods can be coupled with the modified and newly proposed Lax approximations and this coupling make the methods conservative. Some additional new classes of explicit and implicit methods for PDEs in time are proposed. Additionally, some new methods are given to reduce oscillations in the solutions. These new methods of reducing oscillations provide the conditions for coupling of first and higher-order methods.     

Room temperature ferromagnetism of Si-doped ZnO thin films prepared by sol–gel method

Pure ZnO and Si-doped ZnO thin films were deposited on quartz substrate by using sol-gel spin coating process. X-ray diffraction analysis shows that all the thin films have hexagonal wurtzite structure and preferred c-axis orientation. Si-doped ZnO films show room temperature ferromagnetism (RTFM) and reach the maximum saturation magnetization value of 1.54 kAm-1 at 3% Siconcentration. RTFM of Si-doped ZnO decreases with the increasing annealing temperature because of the formation of SiO 2 . Photoluminescence measurements suggest that the RTFM in Si-doped ZnO can be attributed to the defect complex related to zinc vacancies V Zn and oxygen interstitials Oi .     

Polyphenylglyoxamide-Based Amphiphilic Small Molecular Peptidomimetics as Antibacterial Agents with Anti-Biofilm Activity

The rapid emergence of drug-resistant bacteria is a major global health concern. Antimicrobial peptides (AMPs) and peptidomimetics have arisen as a new class of antibacterial agents in recent years in an attempt to overcome antibiotic resistance. A library of phenylglyoxamide-based small molecular peptidomimetics was synthesised by incorporating an N-alkylsulfonyl hydrophobic group with varying alkyl chain lengths and a hydrophilic cationic group into a glyoxamide core appended to phenyl ring systems. The quaternary ammonium iodide salts 16d and 17c showed excellent minimum inhibitory concentration (MIC) of 4 and 8 μM (2.9 and 5.6 μg/mL) against Staphylococcus aureus, respectively, while the guanidinium hydrochloride salt 34a showed an MIC of 16 μM (8.5 μg/mL) against Escherichia coli. Additionally, the quaternary ammonium iodide salt 17c inhibited 70% S. aureus biofilm formation at 16 μM. It also disrupted 44% of pre-established S. aureus biofilms at 32 μM and 28% of pre-established E. coli biofilms 64 μM, respectively. A cytoplasmic membrane permeability study indicated that the synthesised peptidomimetics acted via disruption and depolarisation of membranes. Moreover, the quaternary ammonium iodide salts 16d and 17c were non-toxic against human cells at their therapeutic dosages against S. aureus.     

Effect of halide ions on passivation and pitting Corrosion of copper in alkaline solutions

The passivity of copper in NaOH and borate buffer solutions containing chloride, bromide and fluoride ions was studied by using cyclic voltammetry and potentiostatic current transient measurements. At scan rates ≥ 20 mVs^?1, the addition of halide ions does not nearly affect the cyclic voltammograms in the absence of pitting. But they differ considerably in presence of pitting. The pitting potential was found to depend on the solution pH and decreased linearly with increase of logarithm of halide ion concentration. The current transients in the passivity as well as in the pitting potential regions were analyzed. Before the pitting, i-time curves were rather similar to those obtained in the plain solutions. At times > 20 seconds, the current varies linearly with the reciprocal of the square root of time indicating diffusional characteristics of the metal corrosion through the passive layer. In presence of pitting, the pitting current versus time relations fit the Engell-Stolica equation.     

Delay-line readout for multicell detectors

A simple delay-line readout method has been tested with a position-sensitive photomultiplier. Position accuracies of the reconstruction by means of a time-to-amplitude convertor are quite comparable to those obtained by a conventional centroid method using a number of analog-to-digital convertors.

In this way, a simple and economic solution can be conceived for the readout of not only position-sensitive photomultipliers, but also arrays of different kinds of position detectors.     

Detection of soybean in soy-based meat substitutes

The statistical analysis of the available data indicated that the straight line equations of protein, fat, fibre, calcium, methionine, and lysine could successively be used for forecasting the added soy percent in a given recipe. On the other hand, the areas of the identified bands in the electropherograms of the investigated samples were considered a reasonable tool for the quantitative determination of whole soybean in soy-based meat substitutes.