Fabrication of a novel latex-based membrane for oily wastewater filtration: effect of degassing on the properties of membrane

Iranian Polymer Journal - Nitrile butadiene rubber latex/graphene oxide (NBR/GO) membranes were fabricated by latex compounding and curing method. This was a new method to produce membrane, thus,...     

The thermal conductivity of oils sands

Measurements have been made of the effective thermal conductivity of some samples of Athabasca oil sands using a steady state method over the temperature range 20°C – 120°C. The bitumen content of the samples was altered from its natural value by mixing with additional sand and the resulting values of the thermal conductivity were found to increase with increasing the oil content. Moreover, the effective thermal conductivity values were found to decrease with increasing temperature.     

A tabu search with an oscillation strategy for the discriminant analysis problem

This article proposes a tabu search approach to solve a mathematical programming formulation of the linear classification problem, which consists of determining an hyperplane that separates two groups of points as well as possible in ?^m. The tabu search approach proposed is based on a non-standard formulation using linear system infeasibility. The search space is the set of bases defined on the matrix that describes the linear system. The moves are performed by pivoting on a specified row and column. On real machine learning databases, our approach compares favorably with implementations based on parametric programming and irreducible infeasible constraint sets. Additional computational results for randomly generated instances confirm that our method provides a suitable alternative to the mixed integer programming formulation that is solved by a commercial code when the number of attributes m increases.     

Effect of Synthesis Technique and Carbonate Content on the Crystallinity and Morphology of Carbonated Hydroxyapatite

The syntheses of nanosized carbonated hydroxyapatite（CHA） were performed by comparing dropwise and direct pouring of acetone solution of Ca（N0₃）₂-4H₂0 into mixture of（NH₄）₂HP0₄ and NH₄HCO₃ at room temperature controlled at pH 11.Direct pouring method was later applied to study the increment of carbonate content in syntheses.The as-synthesized powders were characterized by various characterization techniques.The crystallographic results of the produced powders were obtained from X-ray diffraction analysis,whilst the carbonate content in the produced powders was determined by the CHNS/O elemental analyzer.Fourier transform infrared analysis confirmed that the CHA powders formed were B-type.Field emission scanning electron microscopy revealed that the powders were highly agglomerated in nanosized range and hence energy filtered transmission electron microscopy was employed to show elongated particles which decreased with increasing carbonate content.     

Exploiting the Plackett–Burman design to examine the formulation effect on curing characteristics of oil palm ash-filled acrylonitrile butadiene rubber compounds

The present paper is focused on exploiting Plackett–Burman design to examine the formulation effect of various chemical components content on the curing characteristics of oil palm ash (OPA)-filled acrylonitrile butadiene rubber (NBR) compound. The filled-NBR compound was prepared by conventional laboratory-sized two roll mill and cured using sulfuric system. Six independent variables such as content of zinc oxide, stearic acid, N-isopropyl-N′-phenyl-p-phenylenediamine, N-cyclohexyl-2-benzothiazole sulfenamide (CBS), sulfur, and even OPA filler were carried out to screen their significant effect on the curing characteristics of NBR compound. The scorch time, optimal cure time, minimum torque, and maximum torque were selected as a response. Results showed that the scorch time and the optimal cure time were significantly affected by CBS, whereas the minimum torque and maximum torque were significantly affected by OPA and sulfur, respectively, within the studied range. Among the chemical components under study, zinc oxide and stearic acid had the least effect on the curing properties of NBR compound. Analysis of variances for all factorial models demonstrated that the model was significant with P value <0.05 while the regularity (R ²) of all models was greater than 0.9. Lastly, the optimal chemical concentrations were predicted to acquire the optimal condition of the curing system for filled-NBR compound.     

Effects of dynamic vulcanization on tensile,morphological, and swelling properties of poly(vinyl chloride) (PVC)/epoxidized natural rubber (ENR)/(Kenaf core powder) composites

The effects of dynamic vulcanization on properties of poly(vinyl chloride) (PVC)/epoxidized natural rubber (ENR)/(kenaf core powder) composite were studied. Tensile properties indicated that the strength, elongation at break, and Young's modulus of the composites exhibited an increase for samples with dynamic vulcanization. Morphological analysis using scanning electron microscopy showed the interaction between ENR and PVC. There was no bonding between kenaf core powder and the PVC/ENR matrix owing to the different polarity of both components. Filler agglomerates increased, which leads to an increase of filler‐filler interaction and poor dispersion. Furthermore, swelling index indicated that the composite with dynamic vulcanization shows lower absorption of tolune compared with composites without dynamic vulcanization. J. VINYL ADDIT. TECHNOL., 22:206–212, 2016. © 2014 Society of Plastics Engineers     

Influence of kenaf form and loading on the properties of kenaf‐filled polypropylene/waste tire dust composites: A comparison study

Kenaf (KNF)‐filled polypropylene/waste tire dust (PP/WTD) composites containing different KNF loadings (0, 5, 10, 15, and 20 parts per hundred parts of resin (phr)) were prepared using a Thermo Haake Polydrive internal mixer. The influence of the KNF form (KNF short fiber (KNFs) and KNF powder (KNFp)) at different KNF loadings on properties of the composites was studied. Results showed that with increasing KNF loading, the stabilization torque, tensile modulus, water absorption, and thermal properties increased for both KNFp‐ and KNFs‐filled PP/WTD composites. However, the tensile strength and elongation at break decreased by 29.2% and 53.9%, respectively, for KNFp‐filled PP/WTD composites, whereas KNFs‐filled PP/WTD composites showed a decrement of 24.5% and 63.5%, respectively. The stabilization torque, tensile strength, and tensile modulus increased by 22.4%, 6.7%, and 2.6%, respectively, for KNFs‐filled PP/WTD composites at 20 phr KNF loading. The scanning electron microscopy morphological studies on the tensile fractured surfaces revealed poor adhesion between KNFp and PP/WTD matrices as compared to KNFs and PP/WTD matrices. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40877.     

Effects of partial replacement of commercial fillers by recycled poly(ethylene terephthalate) powder on the properties of natural rubber composites

Commercial fillers, including carbon black (N550), halloysite nanotubes (HNTs), and precipitated silica, were replaced by recycled poly(ethylene terephthalate) powder (R‐PET) in natural rubber (NR) composites. Five different compositions of NR/N550/R‐PET, NR/HNTs/R‐PET, and NR/silica/R‐PET compounds, i.e., 100/20/0, 100/15/5, 100/10/10, 100/5/15, and 100/0/20 parts per hundred rubber (phr), were prepared on a two‐roll mill. The curing behavior, tensile properties, and morphological characteristics of the natural rubber composites were investigated. The results indicated that the replacement of carbon black, HNTs, and silica by R‐PET decreased the tensile strength and tensile modulus, such that NR/silica/R‐PET composites showed the lowest effect, followed by NR/HNTs/R‐PET and NR/N550/R‐PET composites. The negative effect on these properties can be explained by the decrease of crosslink density. The curing results revealed that with the replacement of carbon black by R‐PET, the scorch time and cure time decreased, but that the NR/HNTs/R‐PET and NR/silica/R‐PET composites exhibited the opposite trend. Scanning electron microscopy investigation of tensile fracture surfaces confirmed that the co‐incorporation of N550/R‐PET improved the dispersion of R‐PET and enhanced the interaction between the fillers and NR matrix more than R‐PET and silica/R‐PET hybrid fillers. J. VINYL ADDIT. TECHNOL., 2012. © 2012 Society of Plastics Engineers     

Three-stage hybrid-flowshop model for cross-docking

This paper deals with the optimization of a cross-docking system. It is modeled as a three-stage hybrid flowshop, in which shipments and orders are represented as batches. The first stage corresponds to the receiving docks, the second stage corresponds to the sorting stations, and the third stage corresponds to the shipping docks. The objective of the problem is to find a schedule that minimizes the completion time of the latest batch. In order to obtain good quality feasible solutions, we have developed several heuristic schemes depending on the main stage considered, and several rules to order the batches in this stage. Then, we propose a branch-and-bound algorithm that takes into account the decomposition of the problem into three stages. To evaluate the heuristics and to reduce the tree size during the branch-and-bound computation, we also propose lower bounds. Finally, the computational experiments are presented to demonstrate the efficiency of our heuristics. The results show that the exact approach can solve instances containing up to 9–10 batches in each stage (i.e., up to 100 jobs). In addition, our heuristics were evaluated over instances with up to 3000 jobs, and they can provide good quality feasible solutions in a few seconds (i.e., less than 2 s per heuristic).     

Continuum redundancy-PLS regression: A simple continuum approach

The relationships between two data sets are investigated. The aim is to predict one data set from the other. New formulations of Redundancy Analysis and Partial Least Square Regression (PLS) are discussed, clearly showing the connexions between these two popular methods. Moreover, it is shown that the Redundancy Analysis and PLS regression are the two end points of a continuum approach. Properties related to this continuum approach are discussed, showing how the multicolinearity problem is handled. The interest of the general strategy of analysis is illustrated on the basis of a data set pertaining to epidemiology.