PSO based economic emission dispatch for fixed head hydrothermal systems

The insufficient hydropower resources along with the deleterious effects of thermal generations necessitate an ingenious scheduling scheme to comply with the growing power demand. The rapidly depleting coal reserve further strengthens the need to develop a new strategy to accomplish generation-load balance at minimum fuel cost over the scheduling horizon, in addition to ensuring reduced emissions. The existing approaches appear to offer suboptimal solutions or suffer from the computational burden due to the large number of problem variables involved. This paper presents an efficient economic emission dispatch strategy involving reduced number of decision variables for hydrothermal scheduling through the use of particle swarm optimisation. The results on three test systems highlight its superior performance and suitability for systems of any size.     

OSMOTIC DEHYDRATION KINETICS OF BLUEBERRIES

Abstract

The kinetics of moisture loss and solids gain during osmotic dehydration of blueberries under different conditions of temperature (37°C - 60°C), concentration of the sucrose solution (47°Brix - 70°Brix) and contact time between fruit and sucrose solution (0.5 h - 5.5 h) were studied, and modeled based on Fick's law of unsteady state diffusion. The study showed that all factors influenced moisture loss and solids gain (p<0.001), both generally increasing with temperature (T) and sucrose concentration (C). Based on the diffusion model, the calculated effective moisture diffusivity (D_m) ranged from 1.98 × 10^?10 to 5.10 × 10^?10 m²/s and the effective solids diffusivity (D_s) ranged from 2.54 × 10^?11 to 2.22 × 10^?10 m²/s. Both D_m and D_s showed increasing trends with temperature and sucrose concentration, and could be modeled as quadratic functions of T and C.     

Steel corrosion in concrete marine structures

Considering this problem in relation to work in developing countries, the authors review an extensive literature and report on their own tests. The results highlight the aggressive effects of magnesium sulphate, but the experiments also show that a small quantity of bentonite added to the mixing water can effectively improve resistance.     

An Ultrasonic Method for Assessing the Residence Time Distribution of Particulate Foods During Ohmic Heating

ABSTRACT: The residence time distribution (RTD) was investigated using ultrasound during continuous ohmic heating of 1) starch solution and 2) carrot particles/starch solution mixtures. For liquid experiments, a copper pigment was used as a tracer. Ultrasonic sensors were placed at the end of the tube to measure changes in sound attenuation. The copper concentration was determined in samples taken at time intervals. For particulate foods, one kilogram of carrot/solution mixtures was introduced. Results of the ultrasonic method were compared to carrots weights in collected samples. Variations of sound attenuation illustrated well the RTD of solutions and carrot particles. Results of the ultrasonic method agreed with the pigment method for liquid and the gravimetric method for particulate foods.     

Significance of structure-property relationship in alumina based porcelain insulators to achieve quality

The catastrophic failures of porcelain insulators in power lines can be minimized by understanding the structure-property relationship that governs the performance. A study addressing the materials aspects has been conducted on alumina based porcelain insulators used in 25 kV railway traction lines. This article asserts the controls exercised by chemical composition, crystalline structural phases and microstructure on the functional reliability and durability of the insulators. Influences of the total alumina, α-Al₂O₃ (corundum) and α-quartz contents, microstructural features including morphologies of mullite needles, quartz and corundum grains in the alumino silicate glassy matrix, large inhomogeneities in matrix constituents and composition have been highlighted.     

Direct hydrothermal synthesis of mesoporous Sn-SBA-15 materials under weak acidic conditions

A direct synthetic route for the preparation of Sn-SBA-15 materials with n_Si/n_Sn ratios ranging from 100 to 10 under milder acidic conditions than normally employed for the preparation of Si-SBA-15 is reported. The changes in the pH conditions of the gel were made through an adjustment of the molar ratio of n_H2O to n_HCl (<1 pH <2) during preparation. The samples prepared under three different acidic conditions have been characterized by various techniques. An expansion of the lattice (powder XRD) and an increase in mesopore area (low temperature N₂ adsorption) indicate that the hexagonal structure of the SBA-15 is maintained with no loss of long range ordering. The UV–vis reflectance spectra of Sn-SBA-15 samples show the presence of Sn⁴⁺ ions both in tetrahedral and octahedral environment. ²⁹Si MAS NMR spectra of samples prepared under an intermediate acid condition show the presence of Q₃ and Q₄ species. Their ratio increases with a decrease in tin content. The presence of Si in (2Si, 2Sn) i.e., Q₂ environment may point to incorporation of considerable Sn⁴⁺ ions in tetrahedral positions. Sn-Mössbauer spectroscopic studies reveal that Sn²⁺ species form upon reductive treatments and can probably be stabilized in the pore wall upon reoxidation. This to some extent is an indication of the formation and stabilization of Si–O–Sn–O–Si linkages in Sn-SBA-15. A progressive increase in the pH of the medium (increasing the n_H2O to n_HCl ratio) results in the location of Sn⁴⁺ ions, (a) at the surface of the mesopores (surface of the corona region) as a thin film of SnO₂ or small aggregates (loss in mesopore area) depending on the concentration of Sn; (b) at the walls of the mesopore structure, substituting Si⁴⁺ ions (some lattice expansion and tetrahedral Sn⁴⁺ ions); and/or (c) as a part of the corona region, neutralizing the resulting Si–OH groups (a loss of micropore area and octahedral Sn⁴⁺ ions). The studies reveal that the method of preparation, n_H2O/n_HCl ratio and the n_Si/n_Sn ratio (concentration of SnCl₄) of the gel significantly influence the type of tin species in the resulting Sn-SBA-15 samples.     

Compositional Control as the Key for Achieving Highly Efficient OER Electrocatalysis with Cobalt Phosphates Decorated Nanocarbon Florets

Compositional interplay of two different cobalt phosphates (Co(H₂PO₄)₂; Co‐DP and Co(PO₃)₂; Co‐MP) loaded on morphologically engineered high surface area nanocarbon leads to an increased electrocatalytic efficiency for oxygen evolution reaction (OER) in near neutral conditions. This is reflected as significant reduction in the onset overpotential (301 mV) and enhanced current density (30 mA cm^?2 @ 577 mV). In order to achieve uniform surface loading, organic‐soluble thermolabile cobalt‐bis(di‐tert‐butylphosphate) is synthesized in situ inside the nanocarbon matrix and subsequently pyrolyzed at 150 °C to produce Co(H₂PO₄)₂/Co(PO₃)₂ (80:20 wt%). Annealing this sample at 200 or 250 °C results in the redistribution of the two phosphate systems to 55:45 or 20:80 (wt%), respectively. Detailed electrochemical measurements clearly establish that the 55:45 (wt%) sample prepared at 200 °C performs the best as a catalyst, owing to a relay mechanism that enhances the kinetics of the 4e^? transfer OER process, which is substantiated by micro‐Raman spectroscopic studies. It is also unraveled that the engineered nanocarbon support simultaneously enhances the interfacial charge‐transfer pathway, resulting in the reduction of onset overpotential, compared to earlier investigated cobalt phosphate systems.     

Nano‐zero valent iron impregnated cashew nut shell: a solution to heavy metal contaminated water/wastewater

The present research is focused on the removal of Zn(II) ions from aqueous solution using nano zero‐valent iron impregnated cashew nut shell (NZVI‐CNS). The present system was investigated in batch mode operation. NZVI‐CNS was prepared by the liquid‐phase reduction process. The results showed that the NZVI‐CNS exhibited superior adsorption capacity for the removal of Zn(II) ions. Adsorption isotherm and kinetic models were applied to explain the nature of the adsorption process. Adsorption kinetic data followed the pseudo‐first order kinetic model. Moreover, the equilibrium adsorption data were best fitted with a Freundlich model. Langmuir monolayer adsorption capacity was calculated as 94.46 mg of Zn(II) ions/g of NZVI‐CNS. The thermodynamic parameters explain that the present adsorption system was measured as feasible and spontaneous. This newly prepared adsorbent can be successfully applied for the different industrial wastewater treatment. Finally, the exploration asks about contemplated that NZVI‐CNS has exhibited unrivalled adsorption limit. Additionally, NZVI‐CNS is believed to be extremely green and monetarily neighbourly help for wastewater treatment. The results indicate that the feasible approach could be applied in agricultural waste biomass materials for the productive expulsion of heavy metals from aqueous solution and reusing agricultural wastes to facilitate their disposal problem.Inspec keywords: wastewater treatment, contamination, zinc, reduction (chemical), adsorption, monolayers, renewable materialsOther keywords: nano zero‐valent iron impregnated cashew nut shell, aqueous solution, Zn(II) ion removal, NZVI‐CNS, batch mode operation, liquid‐phase reduction process, adsorption capacity, adsorption isotherm models, adsorption kinetic models, adsorption kinetic data, adsorption process, pseudo‐first order kinetic model, equilibrium adsorption data, Freundlich model, Langmuir monolayer adsorption capacity, thermodynamic parameters, adsorption system, industrial wastewater treatment, agricultural waste biomass materials, productive expulsion, heavy metals, waste disposal, Zn