Maleated high oleic sunflower oil‐treated cellulose fiber‐based styrene butadiene rubber composites

Surface treatment of cellulose fibers was performed with maleated high oleic sunflower oil (MSOHO). The MSOHO‐treated cellulose fibers and unmodified cellulose fibers were dispersed in styrene butadiene rubber (SBR) using a two roll mill. Vapor grown carbon nanofibers (VGCNF) were also incorporated at only one parts per hundred rubber (phr) in unmodified cellulose fibers/SBR composites. The curing characteristics, mechanical properties, and water absorption of the resulting composites were determined. MSOHO‐treated fibers completed curing at much slower rate and also decreased the cure density of composites, compared to unmodified fibers. In contrast, the combination of VGCNF and unmodified cellulose fibers accelerated the SBR curing process, but reduced the cure density. MSOHO treatment improved the dispersion of the fibers in the SBR, which resulted in improved mechanical properties of composites. The composite incorporating 1 phr VGCNF and 15 phr unmodified cellulose fibers showed the greatest increase in tensile strength as compared with neat SBR. POLYM. COMPOS. 37:1113–1121, 2016. © 2014 Society of Plastics Engineers     

Review of the main developments in the analytic hierarchy process

In this paper the authors review the developments of the analytic hierarchy process (AHP) since its inception. The focus of this paper is a neutral review on the methodological developments rather than reporting its applications that have appeared since its introduction. In particular, we discuss problem modelling, pair-wise comparisons, judgement scales, derivation methods, consistency indices, incomplete matrix, synthesis of the weights, sensitivity analysis and group decisions. All have been important areas of research in AHP.     

Physico-chemical,morphological and thermal analysis for the combined pozzolanic activities of minerals additives

The research was aimed to evaluate the physico-chemical, morphological and thermal analysis of combined pozzolanic activities of minerals additives. Fly ash and ground granulated blast furnace slag were added, separately and collectively, as mineral replacement in ordinary Portland cement. Tests carried out on specimens cured at different ages were: compressive strength, ultrasonic pulse velocity, X-ray diffraction (XRD) analysis, scanning electron microscopic (SEM) studies, differential thermal analysis (DTA) and thermo-gravimetric analysis (TGA), etc. The results indicated that the compressive strength and ultrasonic pulse velocity development rate of concrete specimens were significantly influenced by the addition of mineral additives. SEM data showed that the fly ash particles were more embedded and surrounded by slag. XRD analysis and DTA/TGA investigation have revealed different reaction kinetics of paste. The peak intensity of calcium hydroxide was significantly retarded by the addition of fly ash and slag, especially in combination, attributed to the dilution effect and calcium hydroxide consumption by pozzolanic reaction.     

Vasculature Segmentation in MRA Images Using Gradient Compensated Geodesic Active Contours

Precise segmentation of vasculature from three-dimensional (3D) magnetic resonance angiography (MRA) images is playing an important role in image-guided neurosurgery, pre-operation planning and clinical analysis. Active Contour based evolution algorithms are being widely applied to MRA data sets, however existing approaches exhibit some difficulties in extracting tiny parts of the vessels. Our objective is to develop an automated segmentation scheme to accurately extract vasculature of the brain, especially tiny vessels. Inspired by the intrinsic properties of MRA, we have proposed a scheme called the gradient compensated geodesic active contours (GCGAC), which compensates for low gradients near edges of thin vessels. The GCGAC, which is implemented based on level set, has been tested on both synthetic volumetric image and real 3D MRA images. Our experiments show that the introduced gradient compensation can facilitate more accurate segmentation of tiny blood vessels.     

Influence of polymerization conditions on the template free synthesis of nanoparticles of poly (1-naphthylamine)

The present article highlights some preliminary investigations on the role of oxidant and medium on the nanostructured morphology of poly (1-naphthylamine) (PNA) prepared via chemical oxidative polymerization. Results revealed that the nano morphology can be controlled under appropriate preparative conditions. The particle sizes were obtained in the range of 5–50 nm exhibiting a much smaller range than polyaniline (PANI) nanoparticles synthesized under similar conditions.     

EFFECT OF MTBE BLENDING ON THE PROPERTIES OF GASOLINE

The effect of blending MTBE in the gasoline was evaluated. MTBE effectively boost the octane numbers of gasoline without adversely effecting its other properties. However, MTBE is not as efficient as leadalkyl compounds as far as the specific octane number improvements are concerned. The addition of 5 to 30 volume percent MTBE increases 1.9 to 11.8 RON of a typical gasoline. MTBE addition also extends the volume of gasoline produces for a given crude by adding volume to the gasoline pool. MTBE provides much higher FEON to the gasoline in comparison with other gasoline components. A higher FEON increases the efficiency of the engine. MTBE is not affected by the lead level of the gasoline. For this reason, lost octane in future lead reductions of the gasoline in Saudi Arabia can be made up with MTBE. MTBE addition to the Saudi gasoline increases the RVP but within the specification of the gasoline. MTBE has favorable effect on the distillation characteristics of the gasoline. MTBE addition lowers the distillation temperature which improves driveability and cold engine operation. MTBEgasoline blends were found free of gums and peroxides after long term storage and pose no phase separation problems in the presence of water. MTBE is miscible in gasoline in all proportions and its solubility in water is low.     

A review of the stabilization of tropical lowland peats

The Deep Mixing Method, which involves the formation of in situ stabilized peat columns, is suitable for deep peat stabilization, whereas the mass stabilization technique is used to stabilize the soil of shallow peat deposits instead of the costly and problematic removal and replacement method. The concept of soil-cement stabilization involves the addition of water to cement, resulting in a chemical process known as cement hydration. Stabilization of peat by cement, which requires a significant strength increase in the cement-stabilized peat or organic soil, is attributed largely to physicochemical reactions that include cement hydration, hardening of the resulting cement paste and interactions between soil substances and primary and secondary cementation hydration products. The factors that affect these physicochemical reactions and the interactions of peat soil-cementation products that influence peat stabilization are the amount of solid particles, the water: soil ratio, the quantity of binder, the presence of humic and/or fulvic acids, the soil pH and the amount of organic matter in the peat. With the Air Curing Technique, stabilized peat samples for unconfined compressive strength (UCS) tests were kept at a normal air temperature of 30 ± 2 °C and strengthened by gradual moisture content reduction instead of the usual water-curing technique or water submersion methods that have been common practice in past experiments involving the stabilization of peat with cement. The principle of using the Air Curing Technique to strengthen stabilized peat is that peat soil at its natural moisture content contains sufficient water (water content from 198 to 417 %) that, when mixed with cement, a curing process takes place that causes the stabilized peat soil to gradually lose its moisture content and to become drier and harder throughout the curing period. This process does not require the addition of water.     

Stability Analysis of Laminated Soft Core Sandwich Plates Using Higher Order Zig-Zag Plate Theory

C₀ finite element model based on higher order zig-zag plate theory is used to study the stability analysis of laminated sandwich plates. The in-plane displacement field is obtained by superposing a global cubically varying displacement field on a zig-zag linearly varying displacement field with different slope in each layer. The transverse displacement assumes to have a quadratic variation within the core and constant in the faces. The conditions regarding transverse shear stress at layer interfaces and top and bottom are satisfied. Numerical examples covering different features of laminated sandwich plates are presented to illustrate the accuracy of the model.     

Selective and differential enumerations of Lactobacillus delbrueckii subsp. bulgaricus, Streptococcus thermophilus, Lactobacillus acidophilus, Lactobacillus casei and Bifidobacterium spp. in yoghurt--a review

Yoghurt is increasingly being used as a carrier of probiotic bacteria for their potential health benefits. To meet with a recommended level of ≥ 10⁶ viable cells/g of a product, assessment of viability of probiotic bacteria in market preparations is crucial. This requires a working method for selective enumeration of these probiotic bacteria and lactic acid bacteria in yoghurt such as Streptococcus thermophilus, Lactobacillus delbrueckii subsp. bulgaricus, Lb. acidophilus, Lb. casei and Bifidobacterium. This chapter presents an overview of media that could be used for differential and selective enumerations of yoghurt bacteria. De Man Rogosa Sharpe agar containing fructose (MRSF), MRS agar pH 5.2 (MRS 5.2), reinforced clostridial prussian blue agar at pH 5.0 (RCPB 5.0) or reinforced clostridial agar at pH 5.3 (RCA 5.3) are suitable for enumeration of Lb. delbrueckii subsp. bulgaricus when the incubation is carried out at 45 °C for 72 h. S. thermophilus (ST) agar and M17 are recommended for selective enumeration of S. thermophilus. Selective enumeration of Lb. acidophilus in mixed culture could be made in Rogosa agar added with 5-bromo-4-chloro-3-indolyl-β-d-glucopyranoside (X-Glu) or MRS containing maltose (MRSM) and incubation in a 20% CO₂ atmosphere. Lb. casei could be selectively enumerated on specially formulated Lb. casei (LC) agar from products containing yoghurt starter bacteria (S. thermophilus and Lb. delbrueckii subsp. bulgaricus), Lb. acidophilus, Bifidobacterium spp. and Lb. casei. Bifidobacterium could be enumerated on MRS agar supplemented with nalidixic acid, paromomycin, neomycin sulphate and lithium chloride (MRS-NPNL) under anaerobic incubation at 37 °C for 72 h.