Glycolysis of Waste Polyurethane Integral Skin Foams from Steering Wheel

As polyurethane integral skin foams are widely used in the automotive industry, in order to decrease the amount of waste disposal of these foams, chemical recycling is preferred as a useful method to achieve both targets: 1) making the industry more compatible with the environment, and 2) defining an economic progress. In this research it has been tried to reconvert integral skin PUF to raw materials by glycolysis. A mixture of diethylene glycol and diethanol amine was used as a solvent system. The product's specifications were analyzed and an amount of recycled polyol usable in foam formulation was adjusted.     

Novel polyfuran/functionalized multiwalled carbon nanotubes composites with improved conductivity: Chemical synthesis,characterization, and antioxidant activity

Novel composites containing very small quantities of functionalized multiwalled carbon nanotubes (MWCNTs‐COOH; 0.025, 0.050, and 0.075 g), and furan were synthesized via in situ chemical oxidative polymerization. The polymerization was carried out in nitromethane at room temperature using anhydrous iron (III) chloride (FeCl₃) as an oxidant. The nanocomposites were characterized by Fourier transform infrared, ultraviolet–visible, X‐ray diffraction, differential scanning calorimetry, and field emission scanning electron microscopy. All synthesized composites were crystalline and showed good solubility in dimethyl sulfoxide and N‐methyl 2‐pyrrolidone. The conductivity of composites was measured with a four‐probe method, and it was found that the electrical conductivity increased by increasing the amount of MWCNTs‐COOH. The maximum electrical conductivity value (6.68 × 10⁻⁴ S cm⁻¹) was obtained for polyfuran/MWCNTs‐COOH (1:0.075, v/w). The resulting composites were analyzed for their antioxidant activity using 2,2‐diphenyl‐1‐picrylhydrazyl assay. The results showed that the antioxidant activity of the composites increased by increasing the amount of MWCNTs‐COOH in nanocomposite. POLYM. COMPOS., 2013. © 2013 Society of Plastics Engineers     

Isolation,Screening, and Characterization of Naphthalene-Degrading Bacteria from Zarand Mine,Iran

ABSTRACT

PAHs are aromatic hydrocarbons with two or more fused benzene rings. They are formed during the thermal breakdown of organic molecules and their succeeding recombination. Naphthalene is the simplest (PAHs) that is carcinogenic. Bioremediation method is considered as an economical and safe approach for the elimination of aromatic compounds from environment. The bacteria were capable to grow on various hydrocarbons like naphthalene. The aim of this research is to isolate and identify naphthalene-degrading bacteria from the coal mine of Zarand. Four samples of water and sludge from various sites of the mine were collected. These sites include the following: Main coal vacate site (MC), Inoculum Sump site (IB), Sludge aggregate site (SA), and Near sludge aggregate site (NF). In this study, 12 bacterial strains that utilize naphthalene at initial concentration 200 mg/L (ppm) as carbon and energy sources for growth were isolated from the Zarand mine in Iran. In addition, bacterial cell density was assayed by measuring the OD₆₀₀. In addition, total naphthalene-degrading bacteria were quantified with the most probable number (MPN) procedure using microtiter plates and the colony-forming unit (CFU) method. The results had shown that most of the naphthalene degrader bacteria aggregated in (SA) site. Six bacteria, isolated from wastewater and oil-contaminated soil showed great potential as naphthalene degraders up to 400 (ppm) and selected for biochemical characteristics. Naphthalene tolerance of the strains in various concentrations of naphthalene indicates that the strain 38 N can grow best at 600 (ppm) naphthalene. This strain was identified based on 16S rRNA gene analysis that showed belonging to Sphingobacterium multivorum AHB38N.     

Covert communication based on energy harvesting and cooperative jamming

Wireless Networks - To prevent detection of communication between legitimate users by warden and guarantee a strong security in wireless networks, covert communication technique is recommended. The...     

Novel conducting nanocomposite based on polypyrrole and modified poly(styrene‐alt‐maleic anhydride) via emulsion polymerization: Synthesis,Characterization, Antioxidant,and heavy metal sorbent activity

Novel polypyrrole/modified poly(styrene‐alt‐maleic anhydride) conducting nanocomposites were prepared via emulsion polymerization using sodium dodecyl sulfate as an emulsifier and ammonium persulfate as an oxidant. Modified poly(styrene‐alt‐maleic anhydride) was used as an external dopant for conductivity enhancement of polypyrrole. The conductivity of nanocomposites was measured with a four‐probe method. The maximum electrical conductivity of the nanocomposite was 1.40 S/cm. The data from this research showed that the novel nanocomposite presents good tendency for the removal of heavy metal ions from aqueous solutions. Also the prepared nanocomposites were analyzed for their antioxidant activity using 2,2‐diphenyl‐1‐picrylhydrazyl assay. The results showed that the antioxidant activity of the nanocomposite was 60%. The nanocomposites were characterized by Fourier transform infrared, ultraviolet–visible, X‐ray diffraction, field emission scanning electron microscopy, and differential scanning calorimetry measurements. POLYM. COMPOS., 36:138–144, 2015. © 2014 Society of Plastics Engineers     

Synthesis and characterization of super dye adsorbent hydrogels based on acrylic acid and acryloyl tetrasodium thiacalix[4]arene tetrasulfonate

Acryloyl tetrasodium thiacalix[4]arene tetrasulfonate (ACSTCA) was synthesized via fictionalization of tetrasodium thiacalix[4]arene tetrasulfonate (STCA). Hydrogels based on acrylic acid (AA) (20–70 mol%) and ACSTCA (30–80 mol%) were prepared by solution copolymerization in water using methylene bisacrylamide and ammonium persulfate as crosslinker and initiator, respectively. The gels obtained exhibited a good ability for absorbing water. Swelling of the gels was improved with increase in ACSTCA content in the gel feed. Characterization of the synthesized monomer (ACSTCA) was performed using mass spectrometry and Fourier transform infrared (FTIR), ¹H and ¹³C NMR spectroscopies and the synthesized gels were characterized by FTIR. The thermal and mechanical properties of these copolymers were also studied using TGA and dynamic mechanical thermal analysis. The glass transition temperature and storage modulus of the copolymer were increased with increasing content of ACSTCA in the gel. Thermal stability was improved with increasing ACSTCA content in the structure of the copolymer. The results showed that the synthesized copolymer (ACSTCA‐AA) can effectively remove dye from wastewater. The dye removal capacity of the gels was investigated with a UV?visible spectrophotometer. In addition, the effect of key operation parameters such as the ACSTCA content in the structure of the copolymer, contact time, adsorbent dosage, pH of the solution and temperature on dye removal from aqueous solution was experimentally studied. The equilibrium data were analyzed using the Langmuir and Freundlich adsorption isotherms. The Freundlich isotherms provided a better fit to the data. Results from the kinetic studies revealed that the adsorption of malachite green onto the hydrogels followed a pseudo‐second‐order kinetic model. © 2015 Society of Chemical Industry     

An Integrated Approach to Lysis-Cryptic Growth (Sludge Ozonation) and Sequencing Batch Reactor Coupled to an Anaerobic Side-Stream Reactor (SBR-ASSR): Performance and Characteristics

ABSTRACT

Anaerobic side-stream reactors (ASSR) have been suggested to reduce waste activated sludge volumes benefiting from relatively low capital/operation costs and design simplicity. In this study, an evaluation of the feasibility of combining the ASSR system with the lysis-cryptic growth (ozonation) process was made so that a part of the sludge which passed through the ASSR anaerobic tank would be then treated by ozonation before returned to the aeration tank. The main independent factor was the ozonation flowrate (OFR), which is defined as the percent of return sludge which passed through the both the anaerobic tank and the ozonation unit. Three systems were studied, an ASSR control without ozonation (OFR-0), a combined ASSR with ozonation designated as OFR-2.5 (anaerobic interchange rate [AIR] of 10% per day and 25% of the exchanged sludge being ozonated [ozone interchange rate or OIR]), and OFR-3.1 (AIR = 12.5%, OIR = 25%). The results revealed that the insertion of an ozonation step led to an enhanced total microbial activity, eukaryotic population, and nitrogen removal. The linear relationship between the observed yield and the specific oxygen uptake rate indicated that microbial predation was the major relevant mechanism for the enhanced sludge reduction. The results of measurements of particle size distribution, and sludge dewaterability rates suggest that additional studies are needed to better understand and optimize this system.     

Modeling Oil Content of Sesame (Sesamum indicum L.) Using Artificial Neural Network and Multiple Linear Regression Approaches

Sesame (Sesamum indicum L.) is an important ancient oilseed crop with high oil content (OC) and quality. The direct selection to improve OC of sesame (OCS) due to low heritability leads to a low profit. The OCS modeling and indirect selection through high‐heritable characters associated with OCS using advanced modeling techniques is a beneficial approach to overcome this limitation that allows breeder to get a better idea of the plant properties that should be monitored during breeding experiments. This study, carried out in 2013 and 2014, compared the potential of artificial neural network (ANN) and multilinear regression (MLR) to predict OCS in the Imamzadeh Jafar plain of Gachsaran, Iran. Principal component analysis (PCA) and stepwise regression (SWR) were used to evaluate 18 input variables. Based on PCA and SWR, the 6 traits of number of capsules per plant (NCP), number of days from flowering to maturity (NDFM), plant height (PH), thousand seed weight, capsule length, and seed yield were chosen as input variables. The network with the sigmoid axon transfer function and 2 hidden layers was selected as the final ANN model. Results showed that the ANN predicted the OCS with more accuracy and efficacy (R² = 0.861, root mean square error [RMSE] = 0.563, and mean absolute error [MAE] = 0.432) compared with the MLR model (R² = 0.672, RMSE = 0.742, and MAE = 0.552). These results showed the potential of the ANN as a promising tool to predict OCS with good performance. Based on sensitivity tests, NCP followed by NDFM and PH, respectively, were the most influential factors in predicting OCS in both models. It seems that a breeding program to select or create long sesame genotypes with a long period from flowering to maturity can be a good approach to address OCS in the future.     

Estimating the power and number of microturbines in small-scale combined heat and power systems

Utilizing the combined heat and power (CHP) systems to produce both electricity and heat is growing rapidly due to their high efficiency and low emissions in domestic, commercial, and industrial applications. In the first two categories among available drivers, due to the compact size and low weight, microturbines are attractive choice. In this paper, by using an energy–economic analysis the type and number of the required microturbines for the specific electricity and heat load curves during a year were selected. For performing this task an objective function annual profit (AP) was introduced and maximized. The operation strategy and the payback period of the chosen system was also determined in this study.     

A three dimensional CFD simulation and optimization of direct DME synthesis in a fixed bed reactor

In this study, a comprehensive three-dimensional dynamic model was developed for simulating the flow behavior and catalytic coupling reactions for direct synthesis of dimethyl ether （DME） from syngas including CO2 in a fixed bed reactor at commercial scale under both adiabatic and isothermal conditions. For this purpose, a computational fluid dynamic （CFD） simulation was carried out through which the standard κ-ε model with 10% turbulence tolerations was implemented. At first, an adiabatic fixed bed reactor was simulated and the obtained results were compared with those of an equivalent commercial slurry reactor. Then the concentration and temperature profiles along the reactor were predicted. Consequently, the optimum temperature, pressure, hydrogen to carbon monoxide ratio in the feedstock and the reactor height under different operation conditions were determined. Finally, the results obtained from this three-dimensional dynamic model under appropriate industrial boundary conditions were compared with those of others available in literature to verify the model. Next, through changing the boundary conditions, the simulation was performed for an isothermal fixed bed reactor. Furthermore, it was revealed that, under isothermal conditions, the performed equilibrium simulations were done for a single phase system. Considering the simultaneous effects of temperature and pressure, the optimum operation conditions for the isothermal and adiabatic fixed bed reactors were investigated. The results of the H2＋CO conversions indicated that, under isothermal condition, higher conversion could be achieved, in compared with that under adiabatic conditions. Then, the effects of various operating parameters, including the pressure and temperature, of the reactor on the DME production were examined. Ultimately, the CFD modeling results generated in the present work showed reasonable agreement with previously obtained data available in the literature.