Hydrotreating rice bran oil for biofuel production

Hydrotreating technique is one of the most promising method for producing high quality of biofuels from plant oils. Here, the non-esculent rice bran oil was subjected to hydrotreatment in a high pressure cata-test unit, using sulfided NiMo/Al₂O₃, catalyst, under various pressures, temperatures and liquid hourly space velocities. The influence of each of these factors on the qualities and quantities of the acquired products was investigated, and the operating conditions were optimized. Evaluation of the final product was made on basis of its fuel characteristics, and compared with those of the raw oil. The results revealed the significant improvement of the physicochemical properties of the hydrotreated product to become very close, or may be better than those derived from petroleum sources.     

Structural Docking Studies of COX-II Inhibitory Activity for Metabolites Derived from Corchorus olitorius and Vitis vinifera

Dietary phenolics have remarkable attention as potential anti-inflammatory agents. This study investigated cyclooxygenase inhibitory activity of nutraceuticals isolated from hydroalcohol extract of Corchorus olitorius L. (Co) and Vitis vinifera L. (Vv). Molecular docking calculations using AutoDock Vina was used to evaluate the binding mode of these nutraceuticals and its major derivatives in the active site of both cyclooxygenase enzymes. In vitro studies showed that quercetin derivatives exhibit a recognizable selective inhibition of cyclooxygenase-II (60%) compared to cyclooxygenase-I (37%). Results showed quercetin ability to explore extra hydrophobic pocket present in the structure of cyclooxygenase-II enzyme, thus explaining its potential selectivity toward cyclooxygenase-II.     

Sequential variable neighborhood descent variants: an empirical study on the traveling salesman problem

In a single local search algorithm, several neighborhood structures are usually explored. The simplest way is to define a single neighborhood as the union of all predefined neighborhood structures; the other possibility is to make an order (or sequence) of the predefined neighborhoods, and to use them in the first improvement or the best improvement fashion, following that order. In this work, first we classify possible variants of sequential use of neighborhoods and then, empirically analyze them in solving the classical traveling salesman problem (TSP). We explore the most commonly used TSP neighborhood structures, such as 2‐opt and insertion neighborhoods. In our empirical study, we tested 76 different such heuristics on 15,200 random test instances. Several interesting observations are derived. In addition, the two best of 76 heuristics (used as local searches within a variable neighborhood search) are tested on 23 test instances taken from the TSP library (TSPLIB). It appears that the union of neighborhoods does not perform well.     

Effect of filler loading on cure time and swelling behaviour of SMR L/ENR 25 and SMR L/SBR blends

The effect of filler loading on the cure time (t₉₀) and swelling behaviour of SMR L/ENR 25 and SMR L/SBR blends has been studied. Carbon black (N330), silica (Vulcasil C) and calcium carbonate were used as fillers and the loading range was from 0 to 40 phr. Results show that for SMR L/ENR 25 blends the cure time decreases with increasing carbon black loading, whereas silica shows an increasing trend, and calcium carbonate does not show significant changes. For SMR L/SBR blends, the cure time of carbon black, silica and calcium carbonate generally decreases with increasing filler loading. The percentage swelling in toluene and ASTM oil no 3 decreases for both blends with increasing filler loading, with calcium carbonate giving the highest value, followed by silica‐ and carbon black‐filled blends. At a fixed filler loading, SMR L/ENR 25 blend shows a lower percentage swelling than SMR L/SBR blends. © 2003 Society of Chemical Industry     

Preparation and Electron Beam Irradiation of PVC/ENR/CNTs Nanocomposites

Poly (vinyl chloride), PVC/epoxidized natural rubber blend, ENR/carbon nanotubes, CNTs nanocomposites were prepared using melt intercalation and solution blending methods. In both preparation methods PVC: ENR: CNTs ratios were fixed at 50:50:2, while the 50/50 PVC/ENR blend without the addition of CNTs was used as control. The PVC/ENR/CNTs nanocomposites were exposed to electron beam (EB) irradiation at doses ranging from 0–200 kGy. The effects of two different preparation methods on the tensile properties, gel fraction and morphology of the PVC/ENR/CNTs nanocomposites were studied. Prior to EB irradiation, the addition of 2 phr of CNTs caused a drop in the tensile strength (Ts) of the 50/50 PVC/ENR blend, implying poor distribution of CNTs in the PVC/ENR blend matrix. However upon EB irradiation, the nanocomposites prepared by the melt blending method exhibited higher values of Ts as compared to the neat PVC/ENR blend due to occurrence of radiation-induced cross-linking in the PVC/ENR blend matrix. Transmission electron microscopy (TEM) images proved that a better dispersion of CNTs in PVC/ENR blend matrix can be achieved by melt intercalation compared to solution blending and the dispersion of CNTs was improved by irradiation. Scanning electron microscopy (SEM) results showed a distinct failure surface with formation of rough structure for the irradiated nanocomposites, which explains the higher values of tensile properties compared to the non-irradiated nanocomposites.     

Effect of Addition of Tertiary-Butyl Hydroquinone into Palm Oil to Reduce Wear and Friction Using Four-Ball Tribotester

Replacing mineral oil with vegetable oils as lubricants continues to attract interest due to their environmentally friendly characteristics and ease of disposal. However, one disadvantage can be low thermal oxidative stability. The purpose of our research is to investigate the ways in which oxidation can be contained by combining palm oil with a phenolic antioxidant. A homogeneous mix of palm oil and tertiary-butyl hydroquinone was found to exhibit satisfactory antioxidant properties and reduce wear and friction. Superior mineral engine oil was used to benchmark the performance.     

A model for anomalous short-channel behavior in submicron MOSFETs

Experimental data and simulation results for submicron MOSFETs are reported and used to support a physical explanation for two important anomalies in the dependence of device threshold voltage on channel length. They are the widely observed increase in threshold voltage with decreasing channel length (roll-up), and the more recent observation that the ultimate threshold voltage decrease (roll-off) occurs at a rate which is far in excess of that which can be explained with conventional models of laterally uniform channel doping. A model that attributes roll-up as well as roll-off to lateral redistribution of doping near the source and drain junctions is proposed. This lateral redistribution is caused by crystal defects formed during post-source/drain-implant anneal. The resulting profile consists of an enhancement of background doping adjacent to the junction edge, bounded by a depression of the doping farther into the channel     

Housing design in relation to environmental comfort — a comparison of the traditional Malay house and modern housing

The changing needs of the Malaysian population mean that there is an urgent necessity for designers to acquire a better understanding of the relationships between climate, building and man. Dr Hanafi outlines some of the choices with diagramatic sketches and makes comparisons between traditional and new forms of construction.     

Mechanical and thermal properties of chitosan‐filled polypropylene composites: The effect of acrylic acid

The mechanical properties, morphology, and thermal properties of chitosan‐filled polypropylene (PP) composites have been studied. The effect of the chemical modification of chitosan by acrylic acid treatment was also investigated. Results showed that the tensile strength and elongation at break decreased but that the Young's modulus of the composites increased with increasing filler loading. Chemical modification of chitosan with acrylic acid improved the tensile strength and Young's modulus of the composites but reduced the elongation at break. Thermogravimetric analysis showed that the addition of chitosan improved the thermal stability of the PP/chitosan composites as compared to that of neat PP. Chemical modification of chitosan had a positive effect on the thermal stability of the composites. This change was attributed to improvement of the interfacial adhesion between the chitosan and PP matrix due to formation of a covalent bond between chitosan and acrylic acid. Meanwhile, differential scanning calorimetric analysis showed that the addition of filler did not significantly change the melting temperature (T_m) of the PP/chitosan composites. The degree of crystallinity of the composites decreased with the addition of chitosan. At a similar chitosan loading, the chemically treated PP/chitosan composites exhibited higher crystallinity than the untreated composites and exhibited slightly increased T_m. A scanning electron microscopy study of the tensile fracture surface of chemically treated PP/chitosan composites indicated that the presence of acrylic acid increased the interfacial interaction between chitosan and the polypropylene matrix. J. VINYL ADDIT. TECHNOL., 2011. © 2011 Society of Plastics Engineers