Analytical Studies of Interaction between Mobility Models and Single-Multi Paths Routing Protocols in Mobile Ad Hoc Networks

Mobile ad hoc networks (MANETs) will play a vital role in civilian and military applications where users move around and share information with each other. The movement of users varies depending on the environment, e.g. people may move randomly in different directions (Random Waypoint and Gauss Markov mobility models); or walk, run and drive in two directions in the street (Manhattan Mobility Model); or move as a group (Reference Point Group Mobility model). The interaction between mobility patterns and routing protocols contributes significantly to vary the overall network performance. We build an analytical framework that shows an analysis structure for the overall network performance test. In this framework, we first compare the properties of the mobility models that are designated for MANETs. Second, we measure single path (proactive and reactive) and multipath (proactive and reactive) routing protocols across the mobility models by tuning into TCP and CBR traffic individually. Finally, we examine the performance of each routing protocol across mobility models and discuss the possibility of interaction between them. Most of the previous findings only evaluate the impact of mobility models and single path routing protocols with CBR traffic, whereas a significant finding of this study is that how the interaction between mobility models and single path and multipath routing protocols varies depending on the usage of traffic (TCP and CBR).     

Coalitional game‐based behavior analysis for spectrum access in cognitive radios

The core of cognitive radio paradigm is to introduce cognitive devices able to opportunistically access the licensed radio bands. The coexistence of licensed and unlicensed users prescribes an effective spectrum hole‐detection and a non‐interfering sharing of those frequencies. Collaborative resource allocation and spectrum information exchange are required but often costly in terms of energy and delay. In this paper, each secondary user (SU) can achieve spectrum sensing and data transmission through a coalitional game‐based mechanism. SUs are called upon to report their sensing results to the elected coalition head, which properly decides on the channel state and the transmitter in each time slot according to a proposed algorithm. The goal of this paper is to provide a more holistic view on the spectrum and enhance the cognitive system performance through SUs behavior analysis. We formulate the problem as a coalitional game in partition form with non‐transferable utility, and we investigate on the impact of both coalition formation and the combining reports costs. We discuss the Nash Equilibrium solution for our coalitional game and propose a distributed strategic learning algorithm to illustrate a concrete case of coalition formation and the SUs competitive and cooperative behaviors inter‐coalitions and intra‐coalitions. We show through simulations that cognitive network performances, the energy consumption and transmission delay, improve evidently with the proposed scheme. Copyright © 2016 John Wiley & Sons, Ltd.     

Cut‐off Frequencies Induced by the Length of Strain Gauges Measuring Impact Events

Abstract: The finite length of strain gauges may induce filtering effects when measuring impact events. In this study, we are interested in quantifying these effects. Precisely, we determined the cut‐off frequencies of strain gauges cemented on visco‐elastic bars and measuring impact‐induced strain waves. This study shows that the cut‐off frequencies increase with the bar’s wave velocity and decrease with the bar’s diameter. The asymptotic value, corresponding to an infinite bar diameter, is reached rapidly (bar diameter ≈ 15 mm). Moreover, we showed that the mode cut‐off frequencies are more severe (lower) than the gauge length cut‐off frequencies for bar diameters greater than 8 mm.     

Ethanol and lactic acid production using sap squeezed from old oil palm trunks felled for replanting

Old oil palm trunks that had been felled for replanting were found to contain large quantities of high glucose content sap. Notably, the sap in the inner part of the trunk accounted for more than 80% of the whole trunk weight. The glucose concentration of the sap from the inner part was 85.2 g/L and decreased towards the outer part. Other sugars found in relatively low concentrations were sucrose, fructose, galactose, xylose, and rhamnose. In addition, oil palm sap was found to be rich in various kinds of amino acids, organic acids, minerals and vitamins. Based on these findings, we fermented the sap to produce ethanol using the sake brewing yeast strain, Saccharomyces cerevisiae Kyokai no.7. Ethanol was produced from the sap without the addition of nutrients, at a comparable rate and yield to the reference fermentation on YPD medium with glucose as a carbon source. Likewise, we produced lactic acid, a promising material for bio-plastics, poly-lactate, from the sap using the homolactic acid bacterium Lactobacillus lactis ATCC19435. We confirmed that sugars contained in the sap were readily converted to lactic acid with almost the same efficiency as the reference fermentation on MSR medium with glucose as a substrate. These results indicate that oil palm trunks felled for replanting are a significant resource for the production of fuel ethanol and lactic acid in palm oil-producing countries such as Malaysia and Indonesia.     

Evaluation on some finishing properties of oil palm plywood

Oil palm is the largest and most important plantation crop in Malaysia. The oil palm generally lasts for 25–30 years before the next replantation is done. Substantial amount of biomass in the form of palm trunk results from plantation cycle. This resource is simply left on the ground to decay and is not used as raw material to manufacture any kind of value-added products. The objective of this study was to investigate the possibility of manufacturing plywood from oil palm trunks and to evaluate some of the finishing properties of such experimental panels in comparison to those from Shorea sp as control samples. Three-ply plywood samples were produced from 5 mm thick veneers of oil palm using urea formaldehyde adhesive. Three types of chemicals, namely nitrocellulose, pre-catalyzed lacquer and polyurethane were used to finish experimental panels. The surface finished with nitrocellulose had the lowest contact angle on raw surface of oil palm plywood and wood. The average cross cut tape index of oil palm plywood was comparable to Shorea sp. All finishing materials of oil palm plywood produced impact rating of 4 except for surface finished with nitrocellulose while finishing on wood indicated an impact rating of 3. Oil palm plywood had higher weight loss compared to Shorea sp. Based on results from contact angle, cross cut tape index, impact rate test, weathering, and soil burial test methods it appears that the samples showed acceptable finishing properties comparable to those of solid wood.     

Application of response surface methodology (RSM) for optimization of cassava starch grafted polyDADMAC synthesis for cationic properties

Response surface methodology was used to study the process optimization of cationic percentage through grafting diallyldimethylammonium chloride (DADMAC) into cassava starch. Based on Box–Behken design, quadratic models were developed to correlate the synthesis variables: concentration of DADMAC (A), concentration of initiator (B), and polymerization temperature (C), to the responses of cationic percentage (y). Analysis of variance (ANOVA) revealed that the concentration of initiator was the most significant variable for the response. The optimum preparation conditions for starch grafted polyDADMAC were 14% cationic using 31 g DADMAC/10 g dry starch of concentration DADMAC, a polymerization temperature of 74°C, and 4.92 g cerric ammonium nitrate/10 mL of initiator concentration.     

Polyphenol-rich seaweed (Eucheuma cottonii) extract suppresses breast tumour via hormone modulation and apoptosis induction

The edible red seaweed Eucheuma cottonii is abundantly cultivated for carrageenan production. This study investigated the effects of dietary E. cottonii polyphenol-rich extract (ECME) on breast cancer. In vitro assays showed that ECME was antiproliferative against oestrogen-dependent MCF-7 and oestrogen-independent MB-MDA-231 human breast-cancer cells (IC₅₀ values of 20 and 42 μg/ml, respectively) but was non-toxic to normal cell lines. The ECME (150 and 300 mg/kg BW) was fed to female rats and, after 4 weeks, rat mammary tumour was induced using LA7 cells (inoculated subcutaneously). The ECME inhibited tumour development and erythrocyte lipid peroxidation in the cancer-induced rats, dose-dependently. It showed anti-oestrogenic effects on the rat estrous cycle and serum hormone levels. Electron microscopy and histopathology observations confirmed apoptosis in the rat mammary tumours. The polyphenol-rich ECME was tumour-suppressive via apoptosis induction, downregulating the endogenous oestrogen biosynthesis, and improving antioxidative status in the rats.     

Al2O3/Yttria‐Stabilized Zirconia Hollow‐Fiber Membrane Incorporated with Iron Oxide for Pb(II) Removal

Removal by absorptive ceramic membranes can simultaneously absorb and separate metal ions from water. Alumina/yttria‐stabilized zirconia (Al₂O₃/YSZ) hollow‐fiber membranes, fabricated using phase inversion and sintering process, were deposited with iron oxide by an in‐situ hydrothermal process. The results showed that α‐Fe₂O₃ was produced and incorporated across the membranes. A reduction in flux was recorded with the deposition of α‐Fe₂O_3. However, it improved the adsorption capacity for heavy metal adsorption. The adsorption‐separation test demonstrated that the optimized membrane is able to completely remove Pb(II) ions after two hours.     

Effect of silicon and heat-treatment temperature on the morphology and mechanical properties of silicon - substituted hydroxyapatite

The precipitation method was used to synthesize silicon-substituted hydroxyapatite with different Si contents of 0.4, 0.8 and 1.6 wt.% (0.4, 0.8 and 1.6Si-HA) using silicon acetate [Si(OCOCH₃)₄] as a Si source. As-synthesized hydroxyapatite (HA) and Si-HA powders/bulks were heat-treated at different temperatures of 1150, 1200 and 1250 °C for 1 h. Pure 0.4Si-HA and 1.6Si-HA were obtained after heat-treatment at all temperatures, whilst α-TCP phase was formed in the 0.8Si-HA sample after heat-treatment at 1250 °C. SEM observation clearly showed that the substitution of Si in HA inhibited the grain growth of Si-HA even at high heat-treatment temperatures (1200 or 1250 °C). The highest diametral tensile strength (DTS) of 15.93 MPa was obtained in the 1.6Si-HA sample after heat-treatment at 1250 °C.