Phoenix dactylifera mediated green synthesis of Cu2O particles for arsenite uptake from water

In this study, an environmentally friendly, cost-effective, and single-step procedure is used for the synthesis of polycrystalline Cu₂O particles with controlled morphologies. Simple sugars are extracted from date fruit pulp (Phoenix dactylifera) and used as a reducing agent for the formation of Cu₂O particles in aqueous medium. The feasibility of this solution is compared with the standard glucose solution. The Cu₂O particles are characterized by electron microscopy, X-ray diffraction, optical absorption and Raman scattering techniques. It is concluded that the morphology of the particles is mainly influenced by the solvents. The obtained Cu₂O particles are then used as an adsorbent to uptake As(III) ions from water. The maximum adsorption capacity (Q_max) is estimated by Langmuir and Freundlich isotherms and it is found that Q_max?=?14.3 mg g^–1. Adsorption kinetics study showed that the adsorption equilibrium could be achieved in 1 h and that the purified water meets the standards of World Health Organization (WHO) for acceptable amount of As(III) in drinking water. Adsorption kinetic models showed that the adsorption is chemisorption in nature.     

Imperfect Preventive Maintenance Policy for Complex Systems Based on Bayesian Networks

The main challenge in maintenance planning lies in the realistic modeling of the maintenance policy. This paper is focused on the maintenance optimization of complex repairable systems using Bayesian networks. A new policy is developed for periodic imperfect preventive maintenance policy with minimal repair at failure; this policy allows us to take into consideration several types of preventive maintenance with different efficiency levels. The Bayesian networks are used for complex system modeling, allowing the evaluation of the model parameters. The Weibull parameters and the maintenance efficiency are evaluated thanks to the proposed methodology using Bayesian inference. The approach developed in this paper is applied on a real system, to determine the optimal maintenance plan for a turbo‐pump in oil industry. Copyright © 2016 John Wiley & Sons, Ltd.     

Design and Analysis of Localized DNA Hybridization Chain Reactions

Theoretical models of localized DNA hybridization reactions on nanoscale substrates indicate potential benefits over conventional DNA hybridization reactions. Recently, a few approaches have been proposed to speed‐up DNA hybridization reactions; however, experimental confirmation and quantification of the acceleration factor have been lacking. Here, a system to investigate localized DNA hybridization reactions on a nanoscale substrate is presented. The system consists of six metastable DNA hairpins that are tethered to a long DNA track. The localized DNA hybridization reaction of the proposed system is triggered by a DNA strand which initiates the subsequent self‐assembly. Fluorescence kinetics indicates that the half‐time completion of a localized DNA hybridization chain reaction is six times faster than the same reaction in the absence of the substrate. The proposed system provides one of the first known quantification of the speed‐up of DNA hybridization reactions due to the locality effect.     

Characterization of virgin olive oil from Southern Tunisia

Fruits from three Tunisian cultivars of Olea europea L. grown in the southeast of Tunisia were harvested at the maturity stage of ripeness and immediately processed with a laboratory mill. There are as yet no data on the chemical composition of virgin olive oils from the southeast of Tunisia, an area characterized by an arid condition of growth for olive trees. Our results showed significant differences in the analytical parameters examined for the three cultivars such as fatty acid composition, total phenols and o‐diphenols, and the content of chlorophylls and carotenoids, confirming the importance of genetic factors in the chemical characteristics of the oil. Headspace solid‐phase microextraction (HS‐SPME) was applied to the analysis of volatile compounds of virgin olive oils. Forty‐eight compounds were isolated and characterized by GC‐RI and GC‐MS, representing 94.1–98.1% of the total amount. (E)‐Hex‐2‐enal, the main compound extracted by SPME, characterized the olive oil headspace for all samples. So, it was clearly shown that there were qualitative and quantitative differences in the proportion of volatile constituents from oils of the various cultivars.     

Novel hydrolysable azo disperse dyes based on N‐ester‐1,8‐naphthalimide: dyeing of polyester–cotton blends

The dyeing of polyester–cotton blends with new alkali‐hydrolysable azo disperse dyes based on N‐ester‐1,8‐naphthalimide was investigated. Polyester–cotton blend fabrics were dyed using both one‐ and two‐bath methods. Dyes 3 and 4 offered lower colour yield on polyester using the one‐bath method. For the rest of the dyes, employing either the one‐ or two‐bath method resulted in a similar colour yield on polyester fabric. The results for fastness properties and colour yield of the dyeings showed that the dyes were suitable for dyeing polyester–cotton blends using the one‐bath method. The kinetic study of hydrolysis of the dyes in alkali media obeyed the pseudo first‐order reaction rate.     

Radiation‐induced grafting of styrene onto poly(tetrafluoroethylene) (PTFE) films. I. Effect of grafting conditions and properties of the grafted films

Radiation‐induced grafting of styrene onto poly(tetrafluoroethylene) (PTFE) films was studied by a simultaneous irradiation technique. Grafting was carried out using γ‐radiation from a ⁶⁰Co source at dose rates of 1.32–15.0 kGy h⁻¹ at room temperature. The effects of type of diluent, dose rate, irradiation dose, and the initial monomer concentration in the grafting solution on the degree of grafting were investigated. The degree of grafting was found to be strongly dependent upon the grafting conditions. The dependence of the initial rate of grafting on the dose rate and the initial monomer concentration in the grafting solution was found to be in the order of 0.6 and 1.7, respectively. The chemical structure and the crystallinity of the grafted PTFE films were studied by means of Fourier‐transform infrared, (FTIR), electron spectroscopy for chemical analysis (ESCA) and X‐ray diffractometry (XRD). © 2000 Society of Chemical Industry     

Protective effect of polyphenol‐rich extract prepared from Malaysian cocoa (Theobroma cacao) on glucose levels and lipid profiles in streptozotocin‐induced diabetic rats

BACKGROUND: Cocoa beans are used for preparing cocoa liquor and cocoa powder, which are the main ingredients of cocoa‐based products. Previous studies have reported the health benefits of cocoa polyphenols in reducing the risk of cardiovascular diseases. However, there is no report on the efficacy of cocoa polyphenols on diabetes mellitus. Therefore this study was designed to evaluate the protective effect of cocoa polyphenol‐rich extract (CE) on glucose levels and lipid profiles in streptozotocin (STZ)‐induced diabetic rats. Male Sprague‐Dawley rats were divided into diabetic control, diabetic CE and diabetic glibenclamide groups. RESULTS: Three different dosages of CE (10, 20 and 30 mg per 100 g body weight) were administered orally once a day for 1 week before STZ injection and for 3 weeks thereafter. The results showed that CE could normalise the body weight loss caused by STZ. In the 20 mg CE‐pretreated group there was a 143% increase in plasma glucose levels, compared with a 226% increase in diabetic control rats. CE could also normalise total cholesterol, triglycerides and high‐density lipoprotein cholesterol at the end of the experiment compared with the baseline. CONCLUSION: The present study suggests that pretreatment with CE from roasted cocoa beans could prevent the development of diabetes induced by STZ injection in rats. Copyright © 2008 Society of Chemical Industry     

An approach to the study of elasto-plastohydrodynamic lubrication in the wire drawing process. Part 2: Theoretical predictions

The generalised Reynolds' equation for Newtonian and non-Newtonian fluids, as applied to the wire-drawing process, together with the plasticity and energy equations have been adopted in solving the elasto-plastohydrodynamic lubrication problem in the wire-drawing process. The equations have been solved numerically using a finite difference technique with Gauss-Siedel iterative scheme to predict hydrodynamic behaviour and to correlate the forming parameters to the lubrication behaviour in an endeavour to find the optimum operating conditions for maximum precision and productivity. The effect of using either Newtonian or non-Newtonian lubricants on the process parameters has been also studied, to predict the most suitable lubricant type. The results indicate that the increase in the flow behaviour index increases the pressure gradient in the work zone, with a consequential reduction in oil film thickness. Also the minimum film thickness is highly influenced by the drawing speed. It can be concluded that the isothermal solution renders lower drawing stress than the adiabatic solution. The maximum shear stress, and hence the power loss, increases with the increase in die convergence angle.