Correction to: Enhanced TOA Estimation Using OFDM over Wide-Band Transmission Based on a Simulated Model

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Urea combustion synthesis of nano-structure bimetallic perovskite FeMnO<Subscript>3</Subscript> and mixed monometallic iron manganese oxides: effects of preparation parameters on structural,opto-electronic and photocatalytic activity for photo-degradation of Basic Blue 12

Nano-structure bimetallic FeMnO₃ and mixed monometallic iron manganese oxides have been synthesized by a urea combustion method using iron (III) choloride, manganese (II) chloride tetrahydrate and urea and calcination at 400 and 650?°C. The structural, optoelectronic and morphological analysis of samples have been studied by XRD, FESEM, EDX, FTIR, and UV–vis DRS measurements. The effect of calcination temperature was examined and XRD results reveal that at 650?°C a pure nano-structure bimetallic FeMnO₃ with perovskite-type structure is formed while at calcination temperature of 400?°C mixed monometallic iron manganese oxides (Fe₂O₃ and Mn₂O₃) is produced. FT-IR spectrum of nano-structure bimetallic FeMnO₃ and mixed monometallic iron manganese oxides exhibited strong absorption band at 473, 523, 547 and 666 cm^?1 for Fe–O, Mn–O and Fe–O–Mn bond stretching vibrations. UV–vis DRS absorption spectrum exhibited absorption peaks at 211, 262, 384 and 520 nm located at UV and visible region of the solar light. FESEM results showed that the pure nano-structure bimetallic FeMnO₃ appears as nano-structure with an average diameter 29 nm. Elemental analysis results of EDX spectrum demonstrated the presence of iron, manganese and oxygen. The photo-catalytic properties of the nano-structure bimetallic FeMnO₃ and mixed monometallic iron manganese oxides coated on glass were evaluated via degradation of Basic Blue 12 (BB12) an oxazine class dyes under irradiation. The results showed the best photocatalytic performance, which achieved as high as 99% for BB12 degradation exposed 1.5 h irradiation which is due to UV and visible absorption, an efficient electron–hole separation and high surface area of nano size particle with an average size of 29 nm. The results showed that nano-structure bimetallic FeMnO₃ and mixed monometallic iron manganese oxides coated on glass is a promising photo-catalyst for the removal of Basic Blue 12 (BB12) an oxazine class dyes from wastewater.     

Controlling foam morphology of polystyrene via surface chemistry,size and concentration of nanosilica particles

Controlling cell morphologies of polymeric foams is an important part of controlling foam properties. In this study, the effects of particle size, particle content, and particle surface chemistry on cell nucleation in nanosilica/polystyrene (PS) composites are investigated. A theoretical hypothesis on the effect of nanoparticle size on cell nucleation in PS matrix foam was examined. The surface chemistry of nanosilica particles was studied by modifying them with Vinyltriethoxysilane (VTES) silane coupling agent. The microcellular porous materials of neat and composite PS were prepared by batch foaming technique (pressure quench) using supercritical carbon dioxide (ScCO₂) as a blowing agent. It was found that the size of the pores decreases and the cell density increases with the decrease in nanosilica size and the increase of silica loading. It was also observed that the surface treatment of the nanosilica particles have substantial effect on the decrease of the cell size and the increase of the cell density.     

Sensitivity Analysis on Ladder Network Equivalent Circuit Parameters of Power Transformer

In this article, novel methods and ideas are introduced, which altogether lead to an accurate model of power transformer windings. First, by the determination of non-dominant (hidden) resonances from frequency-response tests, a ladder model is proposed. Next, it is improved by assigning different values for similar elements of each section of the model. The parameters are obtained by minimizing the error function via a genetic algorithm. Sensitivity analysis is then applied to the obtained model to achieve further examinations and tests. Measurements have been driven from the windings of a 20/0.4-kV, 1600-kVA transformer. Modeling, methodologies, and sensitivity analysis in this article can be very useful for future research aiming to find internal faults of the transformer with the frequency response analysis.     

Biologically‐synthesised ZnO/CuO/Ag nanocomposite using propolis extract and coated on the gauze for wound healing applications

Wound healing has long been recognised as a major clinical challenge for which stablishing more effective wound therapies is necessary. The generation of metallic nanocomposites using biological compounds is emerging as a new promising strategy for this purpose. In this study, four metallic nanoparticles (NPs) with propolis extract (Ext) and one without propolis including ZnO/Ext, ZnO/Ag/Ext, ZnO/CuO/Ext, ZnO/Ag/CuO/Ext and ZnO/W were prepared by microwave method and assessed for their wound healing activity on excision experimental model of wounds in rats. The developed nanocomposites have been characterised by physico‐chemical methods such as X‐ray diffraction, scanning electron microscopy, diffuse reflectance UV–vis spectroscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis and Brunauer–Emmett–Teller analyses. The wounded animals treated with the NPs/Ext in five groups for 18 days. Every 6 days, for measuring wound closure rate, three samples of each group were examined for histopathological analysis. The prepared tissue sections were investigated by haematoxylin and Eosin stainings for the formation of epidermis, dermis and muscular and Masson''s trichrome staining for the formation of collagen fibres. These findings toughly support the probability of using this new ZnO/Ag/Ext materials dressing for a wound care performance with significant effect compared to other NPs.Inspec keywords: nanomedicine, X‐ray diffraction, II‐VI semiconductors, visible spectra, ultraviolet spectra, nanocomposites, biomedical materials, proteins, wounds, nanoparticles, scanning electron microscopy, nanofabrication, skin, zinc compounds, silver, antibacterial activity, Fourier transform infrared spectra, copper compounds, molecular biophysicsOther keywords: propolis, wound healing applications, effective wound, metallic nanocomposites, biological compounds, metallic nanoparticles, microwave method, wound healing activity, physico‐chemical methods, Fourier transform infrared spectroscopy, diffuse reflectance UV‐vis spectroscopy, Brunauer‐Emmett‐Teller analyses, wounded animals, wound closure rate, wound care performance, histopathological analysis, scanning electron microscopy, X‐ray diffraction, thermogravimetric analysis, haematoxylin, Eosin stainings, Masson trichrome, epidermis, muscular trichrome, collagen fibres, time 18.0 d, time 6.0 d, ZnO‐CuO‐Ag     

Production of calcium nitrate crystals via membrane distillation crystallization using polyvinylidene fluoride/sorbitan trioleate membranes

As an alternative to the energy-intensive evaporation-crystallization method, membrane distillation crystallization (MDC) was applied for the first time to obtain calcium nitrate crystals from its aqueous solution. Calcium nitrate solution was obtained through the reaction between calcium carbonate and nitric acid, and then it was concentrated in the membrane distillation (MD) process and further crystallized. The MD step was conducted using hydrophobic polyvinylidene fluoride (PVDF)/sorbitan trioleate (Span 85) membranes. Span 85 was incorporated into the membrane structure in various concentrations to improve the hydrophobicity of membranes, and the resultant membranes were characterized via different methods. In addition, the resultant calcium nitrate crystals were characterized by X-ray fluorescence (XRF) spectroscopy. The MDC results showed that the optimum amount of Span 85 in the polymeric solution was 4%, which led to the formation of a membrane with higher porosity (67.2%) and water contact angle (95.7°) compared to the neat PVDF membrane. The mentioned membrane exhibited the highest water flux in the MD process compared to the other membranes, and also it produced the highest amount of crystals due to its remarkably better performance in the MD step in terms of feed concentration.     

ANN‐based modeling of compact impedance‐varying transmission lines with applications to ultra‐wideband Wilkinson power dividers

The modeling of the physical and electrical characteristics of microstrip non‐uniform transmission lines (NTLs) utilizing artificial neural networks (ANNs) is investigated. The fundamental equations and constraints for designing variable impedance transmission lines are first presented. Then, a proof‐of‐concept example of a compact non‐uniform matching transformer and the counterpart modeled version is elaborated for source and load impedances Z_s and Z_l, respectively, at 0.5 GHz. For comparison purposes, weights and biases of the proposed ANN are established with three different training techniques; namely: backpropagation (BP), Quasi‐Newton (QN), and conjugate gradient (CG); at which the ABCD matrix, impedance variations, input port matching (S₁₁), and transmission parameter (S₂₁) are set as benchmarks to examine the validity of the trained model. The concept is then extended to model a NTL ultrawideband (UWB) Wilkinson power divider (WPD) with three resistors for improved isolation. S‐parameters derived from the trained ANN outputs are close to those obtained by the traditional time‐consuming optimization procedure, and show input and output ports matching and isolation of below ?10 dB, and acceptable values of transmission parameters over the 3.1 GHz to 10.6 GHz band. The resulting models outperform traditional optimizations in terms of simulation time and reserved resources with comparable accuracy. © 2015 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:563–572, 2015.     

Modeling of protein adsorption to DEAE sepharose FF: Comparison of data with model simulation

The equilibrium and kinetic characteristics of the adsorption of human serum albumin (HSA) and ovalbumin (OVA) to the DEAE Sepharose FF weak anion exchanger were experimentally determined. The rate for protein adsorption was simulated with two different models, the first being based on a single lumped kinetic parameter, while the second includes the individual mass transfer processes occurring prior to the adsorption intervention, i.e., diffusion across the liquid film surrounding individual particles and diffusion within the ion exchanger particle itself. The actual adsorption of OVA to DEAE Sepharose FF in fully mixed stirred vessels and in packed bed columns was consistent with both models. In the case of HSA, however, the adsorption profile in an agitated vessel was consistent only with the pore diffusion model and neither model could correctly predict the latter part of the breakthrough profile observed in packed bed experiments.