Design and synthesis of novel di- and triblock amphiphilic polyelectrolytes: Improving salt-induced viscosity reduction of water solutions for potential application in enhanced oil recovery

In the present study, three different block copolymers based on styrene, tert-butyl methacrylate, and glycidyl methacrylate (GMA) were synthesized via sequential atom transfer radical polymerization. The addition of the GMA block was found to be best performed at 60°C. The polymers were then hydrolyzed and neutralized, to afford amphiphilic block copolymers, and the rheological properties of their aqueous solutions were measured, in order to investigate solution properties relevant for enhanced oil recovery, as a function of the polymer structure. It was observed that these polymers behave as thickening agents with shear thinning behavior. As expected, the polymers were sensitive to the presence of salt, as lower viscosities were recorded in saline water. However, the viscosity is less affected by high salinity, when compared to previously studied analogous diblock systems. In the best case, the viscosity only decreased by a factor of 1.8 upon salt addition whereas it decreased by a factor of 10 in previously reported non-GMA containing polymers. Finally, thermo-responsive behavior was found for one of the synthesized polymers. In particular, a hydrolyzed triblock poly[styrene-b-tert-butyl methacrylate-b-glycidyl methacrylate], which synthesis is reported here for the first time, showed a thermothickening behavior, promising for the intended application in oil recovery.     

A survey and qualitative analysis of mac protocols for vehicular ad hoc networks

In order to avoid transmission collisions in mobile ad hoc networks (MANETs), a reliable and efficient medium access control (MAC) protocol is needed. Vehicular MANETs (VANETs) have vehicles as network nodes and their main characteristics are high mobility and speed. Active safety applications for VANETs need to establish reliable communications with minimal transmission collisions. Only few MAC protocols designed for MANETs can be adapted to efficiently work in VANETs. In this article we provide a short overview on some MANET MAC protocols, and then we summarize and qualitatively compare the ones suited for VANETs     

An electrochemical and analytical approach to the inhibition mechanism of an amino-alcohol-based corrosion inhibitor for reinforced concrete

Laboratory investigations were performed in order to assess the effectiveness and the inhibition mechanism of an amino alcohol-based inhibitor currently used as admixture to prevent corrosion of steel in concrete. The investigation was performed in the presence of chloride ions, using solutions simulating the concrete interstitial solution. Electrochemical measurements allowed to conclude that, an inhibitor film is formed on the surface hindering the anodic activity. Furthermore, the analytical investigation through the use of X-ray photoelectron spectroscopy (XPS) shows that the inhibitor film is able to complex with the chloride ion.     

Modern concept of acoustic emission (AE) coupled with electrochemical measurements for monitoring the elastomer-coated carbon steel damage in phosphoric acid medium

Elastomer coatings (rubber) are industrially used to protect phosphoric acid storage tanks against corrosion. Rubber constitutes a barrier against the penetration of H₃PO₄ to metallic surface. Coatings damage induces both acid infiltration and steel corrosion. In this concept, acoustic emission (AE) monitoring technique could be used for the detection of coatings damage as well as for steel corrosion under the coating. In the present work AE was coupled to electrochemical measurements (EM) for rubber damage evaluation and steel corrosion on three types of steels (XC48, E20 and A60) at room temperature in concentrated phosphoric acid (30% P₂O₅) contaminated by Cl⁻, F⁻, SO₄²⁻. Electrochemical behaviour of steels was studied and characterized by potentiodynamic curves and polarization resistance measurement. A good correlation between acoustic emission and polarization resistance or corrosion potential measurements was found during stages of coatings damage and steels corrosion. The majority of AE activity recorded during experiments is related to hydrogen bubbles release. The release of hydrogen bubbles gives rise to two populations of signals: one impulsive and another one resonant.     

Behavior Study of the Nanostructured Zn1-xCdxO (0 ≤ x ≤ 0.1) Semiconductor Thin Films Deposited onto Silicon Substrate by Dip-Coating Method

Silicon - The specimens of nanostructured semiconductor of Zn1-xCdxO (0 ≤ x ≤ 0.1) thin films were grown on silicon substrate using a dip-coating method. The...     

PERMEABILITY ANISOTROPY DISTRIBUTIONS IN AN UPPER JURASSIC CARBONATE RESERVOIR, EASTERN SAUDI ARABIA

Most classical reservoir engineering concepts are based on homogeneous reservoirs despite the fact that homogeneous reservoirs are the exception rather than the rule. This is especially true of carbonate reservoirs in the Middle East which are known to be highly heterogeneous. The realistic petrophysical characterization of these kinds of reservoirs is not an easy task and must include the study of directional variations of permeability. Such variation can be incorporated into engineering calculations as the square root of the ratio of horizontal to vertical permeability, a parameter known as the anisotropy ratio.
This paper addresses the distribution of anisotropy ratio values in an Upper Jurassic carbonate reservoir in the Eastern Province of Saudi Arabia. Based on whole core data from a number of vertical wells, statistical distributions of horizontal and vertical permeability measurements as well as anisotropy ratios were determined. The distributions of both permeability measurements and anisotropy ratios have similar patterns characterized by considerable positive skewness. The coefficients of variation for these distributions are relatively high, indicating their very heterogeneous nature.
Comparison of plots of anisotropy ratios against depth for the wells and the corresponding core permeability values indicate that reservoir intervals with lower vertical permeability yield consistently higher ratios with considerable fluctuations. These intervals are represented by lower porosity mud-rich and/or mud-rich/granular facies. Granular facies, on the other hand, yielded considerably lower ratios without significant fluctuations.     

Influence of Low Cd-Doping Concentration (0.5 and 3 wt.%) and Different Substrate Types (Glass and Silicon) on the Properties of Dip-Coated Nanostructured ZnO Semiconductors Thin Films

Journal of Inorganic and Organometallic Polymers and Materials - The investigation of semiconductor films of undoped ZnO and doped with two weight percentages of Cadmium (0.5 and 3) were grown on...     

A new branch-&-bound-enhanced genetic algorithm for the manufacturing cell formation problem

This paper deals with the manufacturing cell formation (MCF) problem, which is based on group technology principles, using a graph partitioning formulation. An attempt has been made to take into account the natural constraints of real-life production systems, such as operation sequences, minimum and maximum numbers of cells, and maximum cell sizes. Cohabitation constraints were added to the proposed model in order to deal with the necessity of grouping certain machines in the same cell for technical reasons, and non-cohabitation constraints were included to prevent placing certain machines in close vicinity.     

A new generalized stochastic Petri net modeling for energy-harvesting-wireless sensor network assessment

This paper proposes an energy-harvesting-aware model that aims to assess the performances of wireless sensor networks. Our model uses generalized stochastic Petri nets to define a sensor–neighbors relationship abstraction. The novelty of the proposed formulation is taking into account several real-life considerations such as battery-over breakdowns, unavailability of neighbors, retrial attempts, and sleeping mechanism in a single model. We use TimeNet tool to simulate the network behavior in order to evaluate its performance throughout different formulas after it had reached its steady state. Finally, we present a case study featuring the different solar energy recovery capabilities of the vast Algerian territory. The aim is to show with the presented model how to determine the kind of resources to be acquired in order to cope with the sensor deployment project requirements. The proposed model allows us to ensure that the battery energy level of sensors deployed in Algiers province for example is almost equal to 80% for 100 messages per day and (1 min/2 min) for (awakening time/sleeping time) ratio.