Galvano-Fenton Engineering Solution with Spontaneous Catalyst’s Generation from Waste: Experimental Efficiency,Parametric Analysis and Modeling Interpretation Applied to a Clean Technology for Dyes Degradation in Water

In this paper, the degradation of the diazo dye naphthol blue black (NBB) using the Galvano-Fenton process is studied experimentally and numerically. The simulations are carried out based on the anodic, cathodic, and 34 elementary reactions evolving in the electrolyte, in addition to the oxidative attack of NBB by HO• at a constant rate of 3.35×107 mol−1·m3·s−1 during the initiation stage of the chain reactions. The selection of the operating conditions including the pH of the electrolyte, the stirring speed, and the electrodes disposition is performed by assessing the kinetics of NBB degradation; these parameters are set to 3, 350 rpm and a parallel disposition with a 3 cm inter-electrode distance, respectively. The kinetics of Fe(III) in the electrolyte were monitored using the principles of Fricke dosimetry and simulated numerically. The model showed more than a 96% correlation with the experimental results in both the blank test and the presence of the dye. The effects of H2O2 and NBB concentrations on the degradation of the dye were examined jointly with the evolution of the simulated H2O2, Fe2+, and HO• concentrations in the electrolyte. The model demonstrated a good correlation with the experimental results in terms of the initial degradation rates, with correlation coefficients exceeding 98%.     

A delay-based admission control mechanism for multimedia support in IEEE 802.11e wireless LANs

Multimedia over IEEE 802.11 wireless local area networks (WLANs) has recently been the focus of many researchers due to its rapidly increasing popularity. Unlike their best-effort counterparts, multimedia applications have quality of service (QoS) needs typically expressed in terms of the maximum allowed delay and/or the minimum required throughput. Therefore, prior to accepting a multimedia application, the network must assure the satisfaction of its QoS requirements. In this paper, we develop a mechanism that can be used to control the admissibility of multimedia applications into WLANs. To develop the proposed mechanism, we first derive an analytical approximation of the delay experienced by packets when travelled through these networks. The analytical approximation of the delay is then used to propose an admission control mechanism for the enhanced distributed channel access (EDCA) method used by the hybrid coordination function (HCF) of IEEE 802.11e. The proposed delay-based admission control mechanism is validated via simulations of voice traffic.     

Enhanced sonolytic mineralization of basic red 29 in water by integrated ultrasound/Fe2+/TiO2 treatment

Research on Chemical Intermediates - Advanced oxidation processes (AOPs), based on hydroxyl radical (·OH) induced oxidation, have been widely investigated to develop novel and green...     

Exploration of the reactivity of N2O5 with two Si(OH)4 monomers using electronic structure methods

The heterogeneous uptake of N₂O₅ on mineral dust particles may play an important role in the removal of nitrogen oxides from the atmosphere. However, the reaction of N₂O₅ with the mineral particles is not well understood. The reaction of N₂O₅ with two Si(OH)₄ monomers is explored using theoretical methods. This study represents a first step towards understanding the interaction of N₂O₅ with the hydroxyl groups of silica particles. Energies are calculated using MP2 single point calculations on the B3LYP optimized geometries and including B3LYP thermodynamic corrections. Four mechanisms are considered for the formation of two HNO₃ and one H₆Si₂O₇. The rate limiting activation barrier of the most favorable path is found to be 12.5 kcal mol^?1. This reaction appears to be more favorable than the hydrolysis of N₂O₅ with one water molecule. These results are in agreement with experimental observations, which show that N₂O₅ reacts with OH groups of Saharan dust to form nitrate. © 2012 Wiley Periodicals, Inc.     

Reinforcement of recycled PP polymers by nanoparticles incorporation

Recycling process seems to be the most efficient way to reduce ecological impacts of used polymers. Nevertheless, the properties of the recycled PP polymer are proved to be insufficient during its reuse, particularly with regard to its thermo-mechanical and rheological behaviors. The incorporation of nanoparticles as fillers into polymer matrix seems to be one of the most successful solutions to upgrade recycled PP polymer. This paper presents an overview on the application of different nanofillers such as clay, calcium carbonate (CaCO₃), Silica (SiO₂), Zinc Oxide (ZnO), carbon black (CB), carbon nanotubes (CNT), antioxidizers and others into recycled PP matrix. Literature works on the effects of nanofillers on obtained nanocomposites are extensively studied. The first section deals with PP recycling and its impact on thermal, mechanical and rheological properties of the polymer. Then, the second part summarizes recent studies on the effects of nanoparticles incorporation on thermo-mechanical and rheological properties of recycled PP. Finally, recyclability of PP-based nanocomposites is discussed.     

A survey and comparative study of QoS aware broadcasting techniques in VANET

Mobile operators currently encounter numerous challenges caused by the centralized architecture of mobile networks. A single mobility anchor placed at the network core maintains the entire mobility and data traffic forwarding in the existing centralized mobility management (CMM) solutions. The CMM approach confronts several issues in scalability, reliability, signaling overhead, and non-optimal routing due to the increasing number of mobile devices and the volume of data traffic. To overcome these issues, a new architectural paradigm called distributed mobility management (DMM) is proposed to flatten the network architecture by moving mobility anchors closer to users and separating the control and data planes at the network edge. Two DMM solutions are developed: partially distributed mobility management (partial-DMM) in which only the data plane is distributed and fully distributed mobility management (full-DMM) where both control and data planes are distributed, which can be potentially applied for future mobile networks. This paper presents a network-based full-DMM scheme that was developed and implemented using NS2 network simulator by removing any dedicated centralized mobility anchor from the architecture. Extensive simulations were conducted to evaluate and compare the performance of the full-DMM model with that of the traditional CMM model. The simulation results show that the full-DMM provides lower end-to-end delay performance than CMM. However, the full-DMM generates higher handover latency and packet loss than CMM at high MN speeds. Moreover, simulation results clearly show the benefits of dynamic mobility activation in the full-DMM model.     

Adsorption of Cu(II) from aqueous phase by Cedar bark

The capability of Cedar bark (Cedrus atlantica Manetti) (CB) for the adsorption of Cu(II) from aqueous solutions was examined. Adsorption isotherm and kinetics of Cu(II) by CB were investigated through a number of batch adsorption experiments. The effect of experimental parameters such as initial Cu(II) concentration, adsorbent mass, initial pH and ionic strength on the removal of metal ions was examined. Equilibrium data were fitted to the Langmuir, Freundlich and Harkins–Jura isotherm models. Experimental equilibrium data were best represented by the Langmuir and Harkins–Jura isotherms. The findings revealed that the CB has the potential to be used as an adsorbent for the removal of heavy-metal ions from aqueous solutions.     

Mitigating jamming attacks in mobile cognitive networks through time hopping

5G wireless networks will support massive connectivity mainly due to device‐to‐device communications. An enabling technology for device‐to‐device links is the dynamical spectrum access. The devices, which are equipped with cognitive radios, are to be allowed to reuse spectrum occupied by cellular links. The dynamical spectrum availability makes cognitive users switch between channels. Switching leads to energy consumption, latency, and communication overhead in general. The performance degrades even more when the network is under jamming attack. This type of attack is one of the most detrimental attacks. Addressing jamming while maintaining a desired quality of service is a challenge. While existing anti‐jamming mechanisms assume stationary users, in this paper, we propose and evaluate countermeasures for mobile cognitive users. We propose two time‐based techniques, which, unlike other existing frequency‐based techniques, do not assume accessibility to multiple channels and hence do not rely on switching to countermeasure jamming. We achieve analytical solutions of jamming, switching, and error probabilities. Based on our findings, the proposed techniques out perform other existing frequency‐based techniques. Copyright © 2016 John Wiley & Sons, Ltd.     

Test Cycle Count Reduction in a Parallel Scan BIST Environment

This paper describes a novel method that can be used to reduce test cycle count in a parallel access scan based Built-In-Self-Test (BIST) environment. An algorithm that allows the efficient application of deterministically generated patterns is proposed. This approach allows BIST fault coverage to be increased using deterministic vectors, while minimizing the cost, in terms of test cycles, of applying the vectors.