Selective Removal of Carbon Dioxide from Wet CO2/H2 Mixtures via Facilitated Transport Membranes containing Amine Blends as Carriers

The selective separation of carbon dioxide (CO₂) from a wet gaseous mixture of CO₂/H₂ through facilitated transport membranes containing immobilized aqueous solutions of monoethanolamine (MEA), diethanolamine (DEA), ethylenediamine (EDA) and monoprotonated ethylenediamine (EDAH⁺) and their blends was experimentally investigated. The effect of CO₂ partial pressure, amine concentration, feed side pressure and amine species on the CO₂ and H₂ permeances were studied. The CO₂ permeability through amine solution membranes decreased with increasing CO₂ feed partial pressure but the H₂ permeance was almost independent of the H₂ partial pressure. A comparison of experimental results showed that single or blended amines with low viscosity and a moderate equilibrium constant, i.e., large forward and reverse reaction rate of CO₂‐amine, are suitable for effective separation of CO₂. The permeability of CO₂ generally increased with an increase in amine concentration, although this increase may be compromised by the salting out effect and decrease in diffusivities of species. The results obtained indicated that CO₂ permeance across a variety of amines are in the order of DEA (2 M) > MD (2 M) > MD (1 M) > MEA (2 M) > MEA (4 M) > MD (4 M) > DEA (1 M) > DEA (4 M) > MEA (1 M) for various concentrations of MEA + DEA blend and are in the order of EDAH⁺ (2 M) > DEA (2 M) > MH (2 M) > DH (2 M) > ED (2 M) > EDA (2 M) > MEA (2 M) for various blends of amine.     

Trans10,cis15 18:2 Isolated from Beef Fat Does Not Have the Same Anti-Adipogenic Properties as Trans10,cis12–18:2 in 3T3-L1 Adipocytes

During ruminal biohydrogenation of α‐linolenic acid, a non‐conjugated non‐methylene interrupted dienoic acid is formed containing a t10 double bond, namely t10,c15–18:2. The present study was designed to examine whether t10,c15–18:2 would exert similar anti‐adipogenic effects compared to t10,c12–18:2 in 3T3‐L1 adipocytes. Differentiated 3T3‐L1 adipocytes were treated with 35 or 70 µM of LNA, t10,c12–18:2, t10,c15–18:2, or bovine serum albumin (BSA) vehicle control for 120 h. Cellular triacylglycerol and protein were quantified using commercial colorimetric kits. Cells were analyzed for fatty acid composition and gene expression using gas chromatography and quantitative PCR, respectively. Trans10,cis12–18:2 decreased (P < 0.05) the adipocyte triacylglycerol (TAG) content, which was mainly related to a reduction in saturated fatty acids (SFA; e.g., 16:0 and 15:0) and cis monounsaturated fatty acids (c‐MUFA; e.g., c9–16:1 and c9–18:1). Trans10,cis12 also decreased (P < 0.05) the expression of genes related to fatty acid synthesis (ACACA, FASN), delta‐9 desaturation (SCD1), fatty acid elongation (ELOVL5), and fatty acid uptake (LPL) and upregulated (P < 0.05) the expression of the rate‐liming enzyme involved in fatty acid β‐oxidation (CPT1). In contrast, LNA and t10,c15–18:2 did not affect the gene expression and cellular content of the TAG, SFA, c‐MUFA, or SCD1 indices in adipocytes. Our findings suggest that t10,c15–18:2, despite having structural similarity to t10,c12–18:2 (presence of a trans‐10 double bond), does not exert anti‐adipogenic effects in 3T3‐L1 adipocytes.     

Simultaneous polarographic determination of isoniazid and rifampicin by differential pulse polarography method and support vector regression

A differential pulse polarography (DPP) for the simultaneous determination of isoniazid and rifampicin was proposed. Under optimum experimental conditions (pH = 7, scan rate = 10 mV/s, pulse amplitude = −50 mV), serious overlapping polarographic peaks were observed in the mixture of these compounds. In this study, support vector regression (SVR) was applied to modeling the overlapped polarograms. Furthermore, a comparison was made between the performance of SVR and partial least square (PLS) on data set. The experimental calibration matrix was designed with 30 mixtures of these compounds. Calibration graphs were linear in the range of 6 × 10⁻⁸-10⁻⁴ and 10⁻⁷-10⁻⁴ M for isoniazid and rifampicin, respectively. The results demonstrated that SVR is a good well-performing alternative for the analysis and modeling of DPP data than the commonly applied PLS technique.     

An optimal algorithm for two robots path planning problem on the grid

This paper is a study on the problem of path planning for two robots on a grid. We consider the objective of minimizing the maximum path length which corresponds to minimizing the arrival time of the last robot at its goal position. We propose an optimal algorithm that solves the problem in linear time with respect to the size of the grid. We show that the algorithm is complete; meaning that it is sure to find an optimal solution or report if any does not exist.     

Wrapping carbon nanotubes by biopolymer chains: Role of nanointerfaces in detection of vapors in conductive polymer composite transducers

Chitosan (CS) and hydrophobic‐modified chitosan (HM‐CS) chains were wrapped onto multiwalled carbon nanotubes (MWNTs) and introduced to polyvinyl alcohol (PVA) matrices as nanohybrid conductive polymer composites (CPCs) for detection of polar vapors. The effect of grafted alkyl groups on polarity of CS chains were studied by quantum mechanics (QM). The designed composites were applied as sensitive layers to clarify the response mechanism in CPCs gas sensors. It was realized that the wrapped biopolymers intensely influenced the sensitivity of the composites. Experiment results specified that the nature of biomacromolecules and their interactions with vapor molecules affects the resistance change in CPCs. The higher interaction of CS with polar vapor molecules caused more plasticization of polymer segments in the MWNTs connections. Such phenomenon enhanced the resistance change in the presence of analytes. Moreover, it was inferred that the semiconductor character of MWNTs has an important effect in the final signals. The more polar structure of CS in comparison with HM‐CS enhanced the adsorption of vapor molecules on the surface of MWNTs, and the electron donor analytes decreased the conductivity of p‐type MWNTs increasing the final responses. The presented results corroborate that the performance of CPCs gas sensors could be finely tuned through manipulation of the nanointerfaces. POLYM. COMPOS., 37:2803–2810, 2016. © 2015 Society of Plastics Engineers     

Agricultural Waste Conversion to Activated Carbon by Chemical Activation with Phosphoric Acid

Activated carbon is widely used in various processes as an inexpensive and effective adsorbent. The adsorption properties of activated carbon vary with the feed materials used and the method of activation. The use of an inexpensive material and performing a suitable production method may help to generate a low cost product. Agricultural wastes could be considered as suitable raw materials for the production of activated carbon. In this work, activated carbon was produced by chemical activation with phosphoric acid of agricultural wastes such as bagasse, hard shells of apricot stones, almond, walnut and hazelnut shells. The effects of various preparation variables on both yield and quality of the prepared carbon were studied. The results showed that the selection of final activation temperature, heating rate, activation time and impregnation rate of the chemical agent was important in determining the quality of activated carbon obtained. The surface area and ash content of the activated carbon produced were compared to those of imported commercial samples. According to the results obtained, activated carbon from the hard shells of apricot stones have the best adsorption properties and the highest surface area. This activated carbon could be used in the separation of metal ions from wastewaters.     

Effect of steel fiber on the mechanical properties of oil palm shell lightweight concrete

This paper reports the results of a study conducted to investigate the effect of low volume content of steel fiber on the slump, density, compressive strength under different curing conditions, splitting tensile strength, flexural strength and modulus of elasticity of a grade 35 oil palm shell (OPS) lightweight concrete mixture. The results indicate that an increase in steel fiber decreased the workability and increased the density. All the mechanical properties except the modulus of elasticity (E) improved significantly. The 28 day compressive strength of steel fiber OPS lightweight concrete in continuously moist curing was in the range of 41–45 MPa. The splitting tensile/compressive and the flexural/compressive strength ratio for plain OPS concrete are comparable with artificial lightweight aggregate. The (E) value measured in this study was about 15.5 GPa on average for all mixes, which is higher than previous studies and is in the range of normal weight concrete. Steel fiber can be used as an alternative material to reduce the sensitivity of OPS concrete in poor curing environments.     

Emulsion liquid membrane pertraction of L-lysine from dilute aqueous solutions by D2EHPA mobile carrier

The results of experimental studies on the batch extraction of L-lysine by emulsion liquid membrane are discussed and the capabilities of this method in the separation of solute from dilute aqueous solutions are shown. Studies on the extraction equilibrium for organic and aqueous phases were performed. The experimental results showed that the degree of extraction was increased by an increase in the pH of the feed phase, the concentration of [H⁺] in the internal phase, and concentration of the carrier in the organic phase. An optimum value of stirring speed was achieved. The rate of water swelling as an undesirable phenomenon was also measured.     

Application of membrane separation processes in petrochemical industry: a review

In this paper a general review on different membrane processes and membrane reactors was done. As the main aim of this paper is to review the application of membrane processes in petrochemical industry, processes such as olefin/paraffin separation, light solvent separation, solvent dewaxing, phenol and aromatic recovery, dehydrogenation, oxidative coupling of methane and steam reforming of methane were discussed in detail. Besides, separation using polymer-inorganic nano composite membranes and wastewater treatment using membrane bio-reactors were reviewed.     

A wrapper‐based feature selection for improving performance of intrusion detection systems

Along with expansion in using of Internet and computer networks, the privacy, integrity, and access to digital resources have been faced with permanent risks. Due to the unpredictable behavior of network, the nonlinear nature of intrusion attempts, and the vast number of features in the problem environment, intrusion detection system (IDS) is regarded as the main problem in the security of computer networks. A feature selection technique helps to reduce complexity in terms of both the executive load and the storage by selecting the optimal subset of features. The purpose of this study is to identify important and key features in building an IDS. To improve the performance of IDS, this paper proposes an IDS that its features are optimally selected using a new hybrid method based on fruit fly algorithm (FFA) and ant lion optimizer (ALO) algorithm. The simulation results on the dataset KDD Cup99, NSL‐KDD, and UNSW‐NB15 have shown that the FFA–ALO has an acceptable performance according to the evaluation criteria such as accuracy and sensitivity than previous approaches.