The Influences of Fibre Parameters on the Tensile and Flexural Response of Lightweight Thermoplastic Kenaf Fibre Reinforced Metal Composites

ABSTRACT

The increasing demand for high performance and lightweight materials has stimulated the development of alternative materials, namely fiber metal laminates (FMLs). FML is a sandwich structure which is formed by bonding the metallic layers with composite as core constituent using an adhesive agent. In this study, the mechanical behavior of FMLs with the core constituents of environmental friendly kenaf bast fiber reinforced polypropylene composites bonded with aluminum skin layers was investigated. The effects of fiber compositions (50, 60, and 70 wt.%), fiber lengths (30, 60, 90 mm), and alkali treatment on the mechanical responses of FML were investigated. The overall results revealed that the increase of fiber composition and fiber length reduces the mechanical strength of FML owing to the agglomeration of natural fibers when the fiber length exceeds the critical limit. However, the chemical treated kenaf bast fiber reinforced FML showed a significant enhancement of the mechanical properties in comparison to the non-treated fiber reinforced FML owing to the improved fiber-matrix adhesion level.     

Methotrexate loaded solid lipid nanoparticles (SLN) for effective treatment of carcinoma

Solid Lipid Nanoparticles (SLN) containing Methotrexate (MTX), an anticancer drug for intravenous administration was formulated and characterized. The SLN dispersions with MTX, stearic acid, and soya lecithin in the ratio of 1:4:1, 1:4:1.5, and 1:4:2, sodium taurodeoxycholate and distilled water were prepared by micro emulsification solidification method. The results show that the prepared MTX-SLN particles (with MTX-Stearic acid-Soya lecithin--1:4:2) have an average size of 270 nm with 51.3% drug entrapment. The in-vitro release was attained up to 15th h. The pharmacokinetic study reveals that the half-life and MRT of SLNs were higher than MTX solution. The life span of EAC (Ehrlich Ascite Carcinoma) bearing mice was increased when treated with MTX-SLNs (Methotrexate nanoparticles). These results clearly indicate that SLNs are a promising sustained release drug targeting system for lipophilic antitumour drugs.     

Correlation between astaxanthin amount and a* value in fresh Atlantic salmon (Salmo salar) muscle during different irradiation doses

The amount of astaxanthin and a* value changes in fresh Atlantic salmon light and dark muscle during cold storage was studied for different e-beam doses (0, 1, 1.5, 2 and 3 kGy). Astaxanthin (mg/kg muscle) and a* value decreased with increasing irradiation dose for both fresh light and dark muscle. The level of irradiation dose gave high correlation between a* value and amount of astaxanthin. The reason for the change in colour or decrease in a* value of Atlantic salmon during irradiation could be due to the destruction of astaxanthin. The amount of astaxanthin and a* value of 1 kGy treated salmon fillets were not significantly different (p > 0.05) from that of the control but significantly different (p < 0.05) from other irradiation treatments. The colour (a* value) of salmon muscle was related to the content of astaxanthin, which decreased as irradiation increased. The amount of astaxanthin in light muscle was three to five times greater than dark muscle. This study demonstrated that irradiating salmon fillets at 1 kGy, can be successfully used and leads to no significant change in colour and amount of astaxanthin.     

Continuous aqueous two-phase extraction of α-lactalbumin from whey in conventional rotating disc contactor

The differential partitioning of α-La to the PEG-rich phase and β-Lg to the salt-rich phase was studied in the continuous extractor, rotating disc contactor (RDC), using polyethylene glycol (PEG) 1000–trisodium citrate system. The performance of the extractor was evaluated in terms of holdup, mass transfer coefficient, extraction efficiency, and recovery by studying the operating variables such as phase velocities and rotor speed. The process conditions for the maximum dispersed phase mass transfer coefficient and recovery of α-La was also obtained and reported.     

Synthesis of metal intercalated clay catalysts for selective hydrogenation reactions

Interlamellar space of the smectite clay minerals have been found as an excellent nano phase reactor due to their easy swelling property and the adsorption capacity. In this work size quantized nano particles of catalytically active noble metals have been generated within the interlamellar space of the smectite type clay minerals. Platinum and ruthenium intercalated/impregnated montmorillonite and hectorite catalysts were synthesised and characterized by various instrumental techniques. Catalytic activity of the synthesised catalysts was evaluated towards hydrogenation of cinnamaldehyde in liquid phase. The effect of various reaction parameters such as temperature, hydrogen pressure, solvents, and amount of catalyst and time on stream on conversion and selectivity were studied and the results are discussed. The studies revealed that noble metal intercalated/impregnated clay catalysts were very effective in hydrogenation reactions as they showed significant conversion and selectivity. Comparison of catalytic activity made with the impregnated catalysts showed that the intercalated catalysts were better than impregnated catalysts in terms of conversion and selectivity.     

Effect of polypropylene fibers on thermogravimetric properties of self‐compacting concrete at elevated temperatures

In this study, the effect of polypropylene (PP) fibers on thermogravimetric parameters of self‐compacting concrete (SCC) containing indigenous materials was investigated experimentally and statistically. The mixes containing cement, water, fly ash, fine aggregate, coarse aggregate, and super plasticizer, with the addition of PP fibers (0%, 0.05%, 0.1%, and 0.15%) by volume of the mixtures, were prepared. The physical properties of SCC were determined at elevated temperatures (200, 400, and 600 °C) after cooling in the laboratory. Regression models were developed to determine the responses, and the optimum amount of 0.05% PP fibers by volume was measured. Copyright © 2012 John Wiley & Sons, Ltd.     

Synthesis, Characterization and Effects of Citric Acid and PVA on Magnetic Properties of CoFe2O4

Cobalt ferrite (CoFe₂O₄) particles were synthesized by sol–gel method using metal nitrates, citric acid (CA) and polyvinyl alcohol (PVA). X-ray diffraction (XRD), high resolution scanning electron microscopy (HR-SEM), thermogravimetry/differential scanning calorimetry analysis and vibrating sample magnetometer were used to study the structural, thermal and magnetic properties of the CoFe₂O₄ powder. XRD results indicate that the resultant particles have crystalline, pure single phase spinel structure. From HR-SEM images, a systematic decrease in particle size is observed with an increase in PVA concentration, along with addition of CA. CA at various concentrations of PVA significantly enhance the magnetic properties of the materials.     

Thermal performance of load‐bearing walls made of cold‐formed hollow flange channel sections in fire

Typical load‐bearing light gauge steel frame (LSF) walls are made of conventional lipped channel section studs and gypsum plasterboards. Current research at the Queensland University of Technology is investigating the effects of using new thin‐walled stud sections on the fire‐resistant rating of LSF walls, in particular, the use of hollow flange channel (HFC) sections. A sound knowledge on the thermal performance of these LSF walls is essential, but expensive and time‐consuming nature of fire tests has acted as a barrier. In this study, finite element models were developed to predict the thermal performance of load‐bearing LSF walls made of HFC section studs exposed to fire on one side. The developed models were validated using the results of five full‐scale standard fire tests of LSF walls. They were then extended to perform a parametric study where the effects of stud dimensions, geometries, spacings and wall configuration were evaluated. The hot and cold flange time‐temperature profiles of HFC studs were developed as a function of the aforementioned parameters, which can be used to predict the fire resistance ratings of LSF walls. This paper presents the fire tests, and the details of the developed finite element models and the thermal performance results of LSF walls made of HFC studs. Copyright © 2015 John Wiley & Sons, Ltd.     

Modified Tsai-Wu failure criterion for fiber-reinforced composite laminates

The Tsai-Wu Quadratic Failure Criterion provides satisfactory strength predictions for fiber-reinforced composite materials but requires five experimental tests to determine the strength parameters. This paper presents two modifications of this criterion, which employ micromechanics to determine these parameters. Experiments on uniaxial and multiaxial vinyl ester/fiberglass composite laminates show that the first modified failure criterion, which is based solely on fiber and resin properties, predicts strength within an average absolute error of 25.4% in comparison to the experimentally determined strength. The addition of a single longitudinal tensile test to the modified expression (second modified failure criterion) reduces the average absolute error to 15.9%. This compares well with the Tsai-Wu Failure Criterion, which gives an average absolute error of 9.4%. The proposed modified criteria are shown to provide satisfactory failure predictions, while greatly reducing the amount of testing required.