Improvement of dewatering capacity of a petrochemical sludge

Oily sludge produced from a petrochemical industry was used to investigate the improvement of its dewatering properties. The oil content (OC) and the dry solid content (DS) of the raw sludge were respectively, 15% and 3.6% by weight. The capillary suction time (CST) and the specific resistance to filtration (SRF) of the raw petrochemical industrial sludge were found to be 2000s and approximately 5.5x10(16)m/kg, respectively. Conventional chemical conditioners such as alum, lime, and polyelectrolyte, and less conventional ones like fly ash, gypsum, and bentonite were used in the sludge conditioning studies. Conventional chemical conditioners gave better results for the enhancement of the dewatering capacity of the sludge. The best result was obtained by using 0.9% cationic polyelectrolyte by weight, and a decrease of 99%-95% were achieved for CST and SRF, respectively, when this dosage of cationic polyelectrolyte was used.     

Flame retardancy and mechanical properties of pet‐based composites containing phosphorus and boron‐based additives

Flame retardancy of poly(ethylene terephthalate), PET, was improved using different flame retardant additives such as triphenylphosphate, triphenylphosphine oxide, zinc borate, and boron phosphate (BP). Composites were prepared using a twin screw extruder and subsequently injection molded for characterization purposes. The flame retardancy of the composites was determined by the limiting oxygen index (LOI) test. Smoke emission during fire was also evaluated in terms of percent light transmittance. Thermal stability and tensile properties of PET‐based composites were compared with PET through TGA and tensile test, respectively. The LOI of the flame retardant composites increased from 21% of neat PET, up to 36% with the addition of 5% BP and 5% triphenyl phosphate to the matrix. Regarding the smoke density analysis, BP was determined as an effective smoke suppressant for PET. Enhanced tensile properties were obtained for the flame retardant PET‐based composites with respect to PET. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42016.     

Regime switching fuzzy AHP model for choice-varying priorities problem and expert consistency prioritization: A cubic fuzzy-priority matrix design

The aim of this paper is to develop a regime switching design of the fuzzy analytic hierarchy process (FAHP) and to improve its functionality under the choice-varying priority (CVP) problem. In the conventional AHP decision process, priority matrices are identical and their values are invariant for a specific objective. However, in many Multi-Criteria Decision Making (MCDM) problems, the relative importance of criteria may differ according to the choices. A regime switching process is proposed for improving the CVP problem. Under the fuzzy-AHP (FAHP) framework, choice-varying priorities are presented in a cubic matrix form. Another novel contribution is suggested in the prioritization of the level of expert consistency. During the decision-making practice, experts may have different attitudes and their individual matrix consistencies might be superior or inferior in their overall practices. Individual consistency is one of the objective indicators of the quality of judgment. An expert consistency prioritization approach is proposed to deal with the classification of response stability. For the financial risk assessment part of the study, the loss probability of the intended projects is calculated by the fuzzy Monte-Carlo simulation framework.