Effect of condensed-phase and gas-phase flame retardants on the ignition behaviour of cotton fabric

The purpose of this study is to evaluate the effect of some well-known flame retardants on the ignition behaviour of cotton fabric. Two types of flame retardants acting in different phases (e.g. condensed phase and gas phase) were used. At low add-on of the retardant acting in the condensed phase the ignition behaviour of the cotton is different from that treated with retardant acting in the gas phase. The condensed-phase retardant caused cotton to burn more rapidly than untreated fabrics. This was attributed to the fact that small add-on of the retardant makes the fuel for the flame available at a lower temperature. However, in the presence of sufficient amounts of retardant, the decomposition of cellulose becomes more directed towards the dehydration mechanism and thus the concentration of the flammable gases is insufficient to reach the flammability limits required. When gas-phase flame retardants were used, a linear dependency of ignition time on the concentration of additive was found. This is explained in terms of the dilution effect of this retardant on the fuel produced from the decomposing fabric.     

Note: Effect of some zinc chelates on the flammability and thermal behaviour of polypropylene

Some zinc chelates were prepared according to conventional methods, and were mixed with polypropylene in the presence and absence of a halogenated compound (Cereclor 70). The effect of these chelates on the flammability and thermal behaviour of polypropylene was studied by measuring the limiting oxygen index values and by the use of thermal analysis. This results showed that these chelates are ineffective in reducing the flammability of polypropylene but their effectiveness is enhanced to varying extents by the addition of Cereclor.     

Protein and oil compositions of sesame seed

The range of protein in the oil-free meal and oil in 20 exotic varieties of sesame ranged from 45.0 to 53.7% and 42.2 to 52.1%, respectively; while in 26 local varieties, the ranges were 45.0 to 60.0% and 41.3 to 49.6%. The fatty acid composition showed only small variability. The local types have higher linoleic acid and lower oleic acid amounts than those of the introduced varieties. The amino acid levels of oil-free sesame meal prepared from both introduced and local varieties were examined. Nearly twofold variations in the limiting amino acids (lysine, isoleucine, methionine, threonine, and valine) were found. Utilization of these variations in amino acid composition should assist the development of sesame protein of improved quality.     

Synthesis and application of novel tricyanofuran hydrazone dyes as sensors for detection of microbes

Acknowledging the need to develop rapid and sensitive bacterial recognition approaches, we functionalised the tricyanofuran hydrazone molecular switch. Of significant interest in relation to the synthesised hydrazones is the formation of two different conjugated structures upon exposure to different pH values. Many bacteria release ammonia gas, which alkalises environments. Herein we report the synthesis of a tricyanofuran hydrazone having the function of a colorimetric pH sensor. The UV‐visible absorption and fluorescence spectra exhibit reversible colour changes of the tricyanofuran hydrazone solution in acetonitrile under acid–base conditions. Our results indicate that the tricyanofuran hydrazone probe can identify the bacterial targets quickly with high sensitivity. The infected samples exhibit a significant colour change from orange to blue and in the mean time there is a decrease in fluorescence emission as a function of ammonia and volatile amines released from bacterial metabolites. This tricyanofuran hydrazone chromophore is proposed for use in food packaging with a pH‐sensing capability.     

Organo Modified Nanoclay/Sawdust Mixtures for Hydrocarbon Removal from Water

Silicon - Organo modified nanoclay (OMNC) and OMNC/sawdust mixture were prepared and applied for hydrocarbon removal from water. Montmorillonite and sawdust were used as raw materials while cetyl...     

Physico-mechanical and photoluminescence properties of EuxMg2−xSiO4 system sintered under different conditions

This work focuses on sintering of Eu_xMg_2?xSiO₄ (x = 0.0, 0.01, 0.03, 0.05) forsterite ceramics under different conditions and study their microstructures, physico-mechanical and photoluminescence characteristics. The starting materials were waste silica fume, pure MgO and europium oxide (Eu₂O₃). The prepared batches were sintered up to 1500 °C in the presence or absence of carbon in ambient atmosphere. The presence of carbon helped in reduction of Eu³⁺ into Eu²⁺. The effect of sintering conditions and formed phases on the properties of final product were investigated. The results indicated that the specimens sintered without carbon exhibited improved physico-mechanical properties with formation of forsterite and Eu_4.67 (SiO₄)₃O precipitated from the formed liquid phase. While the samples sintered in carbon exhibited lower physic-mechanical properties with formation of forsterite and clinoenstatite. Photoluminescence properties were improved with increasing the amount of added Eu₂O₃ for all sintered samples. The specimens sintered without carbon exhibited life time higher than those sintered in the presence of carbon.     

Synthesis and characterization of nanosilver-silicone hydrogel composites for inhibition of bacteria growth

Purpose

Nanosilver-silicone hydrogel (NAgSiH) composites for contact lenses were synthesized to asses the antimicrobial effects.

Biocidal polymers: Synthesis,antimicrobial activity,and possible toxicity of poly (hydroxystyrene‐co‐methylmethacrylate) derivatives

Functionalized polymers have gained much interest in the last decades. This is due to their functional group and their polymer nature that give them unique properties and more advantages than the corresponding small molecules. In this trend, polyhydroxystyrene‐co‐MMA was modified to introduce amino group in the side chain of the polymer. The amine modified polymer was reacted with two classes of active compounds. The first class is aldehydes such as vanilline, p‐hydroxybenzaldehyde, p‐chlorobenzaldehyde, and anisaldehyde. The second class is phenolic esters such as p‐hydroxymethylbenzoate, 2,4‐dihydroxymethyl benzoate, and methyl salicylate. The antimicrobial activities of the polymer and modified polymer with these two classes were explored with Gram‐negative bacteria (Escherichia coli), Gram‐positive bacteria (Bacillus subtilus), fugus like yeast (Candida albicans SC5314), and pathogenic molds (Aspergillus flavus, Trycophyton rubrum, and F. oxysporium). In vitro studies indicated that the start polymer did not affect on the test microorganisms, in contrary to its derivatives. The diameter of inhibition zone varied according to the active group in the modified polymer, polymer microstructure, and the test microorganism. Derivatives I, II, and III were selected among the most effective antimicrobial compounds. Their inhibitory effects on the ratio of surviving cell number (M/C) increased by increasing derivatives concentrations. Derivatives I and II were inhibitorier to C. albicans and molds than to bacteria while derivative III was only antibacterial. These derivatives seemed toxic to Brine shrimp by increasing their concentrations above 10 ppm, with derivative III being the less toxic, compared to others. To clarify this toxic effect and to decrease the toxicity of these derivatives, more detailed studies are necessary, and this will be focused in the nearest future. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

A Survey on Media Independent Handover (MIH) and IP Multimedia Subsystem (IMS) in Heterogeneous Wireless Networks

One challenge of wireless networks integration is to provide ubiquitous wireless access abilities and seamless handover for mobile communication devices between different types of technologies (3GPP and non-3GPP), such as Global System for Mobile Communication, Wireless Fidelity, Worldwide Interoperability for Microwave Access, Universal Mobile Telecommunications System and Long Term Evolution. This challenge is critical as mobile users are becoming increasingly demanding for services regardless of the technological complexities associated with them. To fulfil these requirements for seamless vertical handover (VHO) two main interworking frameworks have been proposed by IEEE Group and 3GPP for integration between the aforementioned technologies; namely, Media Independent Handover IEEE 802.21 and IP Multimedia Subsystem, where each of them requires mobility management protocol to complement its work, such as Mobile IP and Session Initiation Protocol, respectively. Various VHO approaches have been proposed in the literature based on these frameworks. In this paper, we survey the VHO approaches proposed in the literature and classify them into four categories based on these frameworks for which we present their objectives and performances issues.     

Nutritional quality of legume seeds as affected by some physical treatments 2. Antinutritional factors

Raw and treated cowpea, pea and kidney bean seeds were investigated for their content of antinutritional factors including tannins, phytic acid, trypsin inhibitors and oligosaccharides. Treatments applied included water soaking, boiling, roasting, microwave cooking, autoclaving, fermentation and micronization. Kidney bean contained the highest antinutrient content among all investigated seeds. The least tannins and phytic acid contents were recorded in Canadian cowpea while Canadian pea showed the lowest TIA. All treatments conducted caused significant decreases in tannins, phytic acid, TIA and oligosaccharides as compared to the raw seeds. Boiling caused the highest reduction in tannins followed by autoclaving and microwave cooking. Autoclaving and fermentation were the most effective in reducing phytic acid content. Heat treatments (boiling, roasting, microwave cooking and autoclaving) brought a total removal of trypsin inhibitors of all samples. Furthermore, autoclaving caused the highest reduction in oligosaccharides followed by fermentation while the least reductions were caused by either roasting or micronization with no significant difference between these two treatments.