Oil removal from crude oil-in-saline water emulsions using chitosan as biosorbent

ABSTRACT

The sorption of oil from crude oil-in-saline water emulsions was studied using chitosan as biosorbent. The main parameters investigated were chitosan dosage, contact time, and initial crude oil concentration at fixed initial pH. The results showed that the sorption equilibrium was reached within 120 min at oil content as low as 20 mg L^?1. Sorption depends on initial oil concentration and sorbent dosage and may reach up to 95% efficiency in the most favorable conditions. The residual oil concentrations obtained after sorption were always beneath the official limit of oil discharge into environment.     

A Survey of Wireless Communication Technologies for an IoT-connected Wind Farm

Wireless Personal Communications - To satisfy the customer demands, the future wireless communication network can be equipped with high speed connectivity. The 5G technology is going to be a...     

Optimization of machining parameters at high speed drilling of carbon fiber reinforced plastic (CFRP) laminates

High speed machining is now acknowledged to be one of the key manufacturing technologies to ensure high productivity and throughput. Drilling of CFRP, though a challenging task, is being performed successfully at low spindle speeds. However high speed drilling in CFRP thin laminates has not been explored much. This paper reports an experimental investigation of a full factorial design performed on thin CFRP laminates using K20 carbide drill by varying the drilling parameters such as spindle speed and feed rate to determine optimum cutting conditions. The hole quality parameters analyzed include hole diameter, circularity, peel-up delamination and push-out delamination. Analysis of variance (ANOVA) was carried out for hole quality parameters and their contribution rates were determined. Genetic Algorithm (GA) methodology was used in the multiple objective optimization (using MATLAB R2010a software) to find the optimum cutting conditions for defect free drilling. Tool life of the K20 carbide drill was predicted at optimized cutting speed and feed.     

Polyurethane nanoparticles from a natural polyol via miniemulsion technique

Original natural triol (castor oil) was used as a monomer for the synthesis of monodisperse polyurethane nanoparticles (size ranging from 200 to 400 nm) by miniemulsion technique in water. Various parameters such as the concentration of the reactants, the nature of stabilizers and the shear were tuned to control the particle size and its distribution. The polyaddition between the natural triol and isophorone diisocyanate (IPDI) was conducted at 60 °C, in the absence of catalyst and monitored by infrared spectroscopy. The characterization of these polyurethane latexes was carried out using light scattering measurements and transmission electron microscopy (TEM).     

Atomic force microscopy study of comb-like vs. arborescent graft copolymers in thin films

This work deals with the study of comb-like vs. arborescent grafted copolymers made of poly(chloroethyl vinyl ether)-g-polystyrene (PCEVE-g-PS). We describe how the molecular architecture of the branched polymers affects their nanoscale organization in thin films, as observed using atomic force microscopy. The results indicate that modifying the molecular architecture from a ‘generation-zero’ comb-like (PCEVE-g-PS) to a ‘first-generation’ hyperbranched (PCEVE-g-(PS-b-PCEVE-g-PS)) architecture strongly modifies the observed geometrical parameters of the molecules, in good agreement with the expected evolution of the molecular dimensions and the corresponding data obtained in solution.The surface organization of the (PCEVE-g-PS) copolymer molecules is also strongly conditioned by the interplay between the molecule-substrate interactions and the molecule-molecule interactions, leading to different possible orientations of the lateral branches with respect to the surface and thus to different final morphologies.     

Time frequency and wavelet transform applied to selected problems in ultrasonics NDE

In this paper, we contribute by the development of some signal processing in order to enhance the sensibility of flaw detection, to measure thin materials thickness and to characterize defects in nature (planar or volumetric). Features for discrimination of detected echos are extracted in time domain, spectral domain and discrete wavelet representation. Compact feature vector obtained is then classified by different methods: K nearest neighbour algorithm, statistical Bayesian algorithm and artificial neural network. Mallat decomposition algorithm is also developed in order to enhance flaw detectability. Finally, time frequency algorithms based on STFT, Wigner–Ville, Gabor transform are developed and applied to thickness measurements of materials with small thickness.     

Comparison between a polyacrylamide and a hydrophobically modified polyacrylamide flood in a sandstone core

Polymer flooding in oil reservoirs to enhance oil recovery (EOR) has been used worldwide. However, the polymers applied, such as partially hydrolyzed polyacrylamides and xanthan gum, show a number of limitations related to their low salt tolerance and biological degradation, respectively. Therefore, the polymeric properties must be improved to maximize their application. With this goal in mind, a new class of polymers, named “hydrophobically modified water-soluble polymers”, has been developed. These polymers are very similar to conventional polymers used in EOR, except that they have a small number of hydrophobic groups incorporated into the polymer backbone. At incorporation levels of less than 1 mol% these hydrophobic groups can change polymer performance. In this work, a water-soluble polymer made of acrylamide and N,N-dihexylacrylamide was obtained. After characterization of the copolymer, its performance in a porous medium was evaluated through core flood experiments in Botucatu sandstone. In the presence of sodium chloride, the amphiphilic copolymer exhibited a significant increase in viscosity at low polymer concentrations, in addition to resistance factor and residual resistance factor values higher than those of a commercial polyacrylamide. This behavior can increase oil recovery, mainly in high salinity and high-permeability reservoirs, by improving waterflood sweep efficiency.     

Effect of surface mechanical finishes on charging ability of electron irradiated PMMA in a scanning electron microscope

Charging of Polymethyl Methacrylate insulators (PMMA), in a scanning electron microscope (SEM) is studied owing to a time resolved current method. This method allows the evolution of trapped charge versus time and the charging time constant to be deduced. The effect of surface roughness change on the ability of PMMA to trapped charge is highlighted. The results show that the trapped charge at the steady state decreases when the roughness increases in the micrometer range while the time constant of charging increases with surface roughness. This behaviour is due to the increase of leakage current and/or enhanced secondary electron emission (SEE). On the one hand, surface mechanical finishes allows, the build up charge in insulators submitted to an electron bombardment to be lowered. On the other hand this treatment allows the secondary electron emission to be raised for some specific applications.     

Numerical and experimental study of the drilling of multi-stacks made of titanium alloy Ti-6Al-4V: interface and burr behavior

Machining and especially drilling of multi-stacks is a challenge task. In fact, drilling of multi-layers generates several damages such as burr at the hole     

Effect of the Formulation of Sodium Activation Solutions on the Setting Time of Metakaolin Based Geopolymers

Geopolymer materials today represent innovative products,used frequently as a substitute for cementitious traditional materials.They are obtained by the action ...