Search

This study rigorously examined the enhancement of the mechanical properties of clay through the application of disposable face mask fibers (DFMF). By subjecting the reinforced specimens to a comprehensive series of unconfined strength tests, it was found that adding DFMFto the base soil decreased the maximum dry unit weight (MDUW) and increased the optimum moisture content (OMC). The study examined the effects of DFMFcontent on the compounds, revealing that a maximum increase of 0.2 in DFMF content improves their unconfined compressive strength (UCS); Therefore, 0.2% mask DFMFcontent was noticed to be the optimum DFMF content, which constituted maximum strength.

In the present study, magnetic montmorillonite (MMT/Fe3O4) was prepared using chemical precipitation for adsorption of Pb(II) and was characterized by scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis, X-ray diffraction and Fourier-transform infrared spectroscopy (FTIR). The results showed that Fe3O4uniformly occurred on MMT. The maximum adsorption capacity of Pb(II) by MMT/Fe3O4was obtained to be 36.76 mg/g, which was higher than the Fe3O4and MMT alone. The removal efficiency of Pb(II) was strongly dependent on the operating factors, where the maximum efficiency occurred at pH of 5, adsorbent dose of 0.4 g/L, Pb(II) concentration of 30 mg/L, stirring rate of 300 rpm, and contact time of 120 min. The adsorption data followed the Langmuir isotherm, and the kinetic results showed that the chemisorption process is the dominant mechanism for Pb(II) removal. The results of the FTIR analysis explained that the Al–OH and Fe–O functional groups have high participation in pollutant adsorption. The column study emphasized that MMT/Fe3O4nanocomposite has excellent efficiency in the treatment of real wastewater containing Pb(II). In addition, excellent magnetic separation and regeneration performance indicated the applicability of adsorbent for the treatment of synthetic and real solutions. Keywords: MMT/Fe3O4; Pb(II); Column study; Adsorption; Removal mechanism

Presence of aluminum residues in treated water has various health and environmental consequences such as neurotoxicity and possibly Alzheimer’s disease. This study investigated the effects of coagulation/flocculation/sedimentation processes using alum as a coagulant in conjunction with Moringa oleifera coagulant protein (MOCP) as coagulant aid on alkalinity and hardness as well as removal of metal ions and turbidity from turbid water. In this study, MOCP was synthesized and used as a new method of treating turbid water. A conventional jar test apparatus was utilized for the tests. Optimal dosage for MOCP was found at pH of 7–7.5 for all turbidities. Maximum turbidity removal of 99% was achieved. MOCP significantly reduced the required dosage of alum. The values of TOC in treated water in low, medium and high turbidity were 0.55, 0.5 and 0.65 mg L–1, respectively. The efficiency of metal ion removal in the present study was as follows: Fe2+> Cu2+> Zn2+> Mn2+. We demonstrated that this method is an efficient approach for optimization of the coagulation-flocculation process in the treatment of raw water.

This study was conducted to evaluate the potential of the bleached bagasse, cellulose, and nanofiber cellulose to remove methylene blue (MB) from aqueous solution. The morphology of adsorbents surface and their functional groups were examined by using scanning electron microscope and Fourier transform infrared spectroscopy techniques, respectively. In a batch mode study at 25°C temperature, the effects of initial dye concentration, contact time, adsorbent dose, and solution pH on adsorption performance were investigated. The results showed that the percent of MB removal increases by increasing pH and also by increasing sorbent dosage and decreasing initial dye concentration. The adsorption kinetics and equilibrium data were in good agreement with the pseudo-second-order kinetic model and Freundlich adsorption isotherm, respectively. The removal of MB was better and more effective with cellulose and cellulose nanofiber as compared with the bleached bagasse. The regeneration of cellulose and nanofiber cellulose loaded with MB was investigated using electrochemical method under different operating conditions. The results showed that the electrochemical process efficiency is more than 60% for regeneration adsorbents.

Studies have assessed the association between aspartic acid (D)-repeat polymorphism in the gene encoding Asporin (ASPN) and knee osteoarthritis (KOA) risk, but the results were inconclusive and contradictory. Therefore, we performed a meta-analysis to investigate the association between ASPN gene D-repeat polymorphism and KOA risk.

In this paper, cuckoo optimization algorithm is implemented to solve energy production cost minimization in a combined heat and power (CHP) generation system. This problem is also known as combined heat and power economic dispatch problem, which looks for optimal values of power and heat generation of each CHP unit to minimize the total production cost. Cuckoo optimization algorithm is a new metaheuristic algorithm. It is inspired by the life of a bird family, called cuckoo, that special lifestyle of these birds and their characteristics in egg laying and breeding has been the basic motivation for development of this algorithm. Unlike of the some previous approaches, the effect of valve point is considered in the cost function and clearly formulated in the conventional polynomial cost function as absolute sinusoidal term. The proposed method is applied to three small (with three different test cases), medium, and large test systems in order to evaluate its efficiency and feasibility. The obtained results demonstrated a higher quality solution and superior performance of the proposed cuckoo optimization algorithm method in comparison with many existing methodologies.

Air pollution is a challenging issue in some of the large cities in developing countries. In this regard, data interpretation is one of the most important parts of air quality management. Several methods exist to analyze air quality; among these, we applied the Multilayer Perceptron (MLP) and Radial Basis Function (RBF) methods to predict the hourly air concentration of benzene in 14 districts in the municipality of Tehran. Input data were hourly temperature, wind speed and relative humidity. Both methods determined reliable results. However, the RBF neural network performance was much closer to observed benzene data than the MLP neural network. The correlation determination resulted in 0.868 for MLP and 0.907 for RBF, while the Index of Agreement (IA) was 0.889 for MLP and 0.937 for RBF. The sensitivity analysis related to the MLP neural network indicated that the temperature had the greatest effect on prediction of benzene in comparison with the wind speed and humidity in the study area. The temperature was the most significant factor in benzene production because benzene is a volatile liquid.

Background: The emergence of antimicrobial resistant Campylobacter populations, which become an important consideration on the use of antimicrobial agents, especially in veterinary and human medicine, has become a serious concern worldwide. For monitoring the drug resistance, there is a need to develop reliable and reproducible laboratory techniques. There are several methods including disk diffusion, broth micro-dilution, agar dilution, and E-test to determine in-vitro susceptibility profiles of Campylobacter to a range of antimicrobial agents.

For Abstract see ChemInform Abstract in Full Text.