Synthesis of Novel Tetra(µ3-Methoxo) Bridged with [Cu(II)-O-Cd(II)] Double-Open-Cubane Cluster: XRD/HSA-Interactions,Spectral and Oxidizing Properties

A new double-open-cubane core Cd(II)-O-Cu(II) bimetallic ligand mixed cluster of type [Cl₂Cu₄Cd₂(NNO)₆(NN)₂(NO₃)₂].CH₃CN was made available in EtOH/CH₃CN solution. The 1-hydroxymethyl-3,5-dimethylpyrazole (NNOH) and 3,5-dimethylpyrazole (NNH) act as N,O-polydentate anion ligands in coordinating the Cu(II) and Cd(II) centers. The structure of the cluster in the solid state was proved by XRD study and confirmed in the liquid state by UV-vis analysis. The XRD result supported the construction of two octahedral and one square pyramid geometries types around the four Cu(II) centers and only octahedral geometry around Cd(II) two centers. Interestingly, NNOH ligand acts as a tetra-µ³-oxo and tri-µ²-oxo ligand; meanwhile, the N-N in NNH acts as classical bidentate anion/neutral ligands. The interactions in the lattice were detected experimentally by the XRD-packing result and computed via Hirschfeld surface analysis (HSA). The UV-vis., FT-IR and Energy Dispersive X-ray (EDX), supported the desired double-open cubane cluster composition. The oxidation potential of the desired cluster was evaluated using a 3,5-DTB-catechol 3,5-DTB-quinone as a catecholase model reaction.     

HSDN‐GRA: A hybrid software‐defined networking‐based geographic routing protocol with multi‐agent approach

We propose in this paper a Hybrid Software‐Defined Networking‐based Geographical Routing Protocol (HSDN‐GRA) with a clustering approach. It takes into account three different criteria to select the best relay to send data: (1) the contact duration between vehicles, (2) the available load of each vehicle, (3) and the log of encountered communication errors embedded in each cluster head. The multi‐criteria strategy allows the selection of the most reliable vehicles by avoiding communication problems and ensuring connection availability. Once the hybrid control plane has found out the next eligible neighbor, the data plane will be in charge of dividing and sending data. To validate our approach, HSDN‐GRA has been modeled and implemented in JADE, a multi‐agent platform, to be compared to other multi‐agent based protocols. Simulation results show that HSDN‐GRA achieves good performance with respect to the average routing overhead, the packet drop rate, and the throughput.     

Stripping methods studies for HVOF WC-10Co-4Cr coating removal

The use of high-velocity oxyfuel (HVOF) cermet coatings is considered to be a valuable and innovative alternative technology to replace Cr(VI) electroplating. Among others, a WC-10Co-4Cr coating is one of the best choices for landing gear components due to its excellent tribology and corrosion properties. The stripping process of such a cermet coating was studied due to its importance for the repair and overhaul of landing gear components. Stripping solutions fulfill the following criteria: keep substrate integrity; exhibit a high strip rate (SR); lead to uniform dissolution; show no galvanic corrosion; and be environmentally friendly. Three different high-strength steel substrates (4340, 300M, and Aermet100) were studied. Five different stripping solutions were selected for the electrochemical study. Only three met the targeted criteria: the meta-nitrobenzane sulfonate-sodium cyanide solution; the Rochelle salt; and a commercial nickel stripper. It was found that the process must be electrolytic, and that ultrasonic agitation is needed to enhance the overall mass transport and removal of WC particles and metallic matrix residues. When choosing the most efficient solution and conditions, the SR was found to be as high as 162 μm h⁻¹, which is a very acceptable SR for productivity sake.     

Optimal energy-delay tradeoff for opportunistic spectrum access in cognitive radio networks

Cognitive radio (CR) has been considered as a promising technology to enhance spectrum efficiency via opportunistic transmission at link level. Basic CR features allow secondary users (SUs) to transmit only when the licensed channel is not occupied by primary users (PUs). However, waiting for an idle time slot may lead to large packet delays and high energy consumption. We further consider that the SU may decide, at any moment, to use another dedicated way of communication (4G) in order to transmit his packets. Thus, we consider an Opportunistic Spectrum Access (OSA) mechanism that takes into account packet delay and energy consumption. We formulate the OSA problem as a Partially Observable Markov Decision Process (POMDP) by explicitly considering the energy consumption as well as packets’ delay, which are often ignored in existing OSA solutions. Specifically, we consider a POMDP with an average reward criterion. We derive structural properties of the value function and we show the existence of optimal strategies in the class of the threshold strategies. For implementation purposes, we propose online learning mechanisms that estimate the PU activity and determine the appropriate threshold strategy on the fly. In particular, numerical illustrations validate our theoretical findings.     

Synergy of climate change and local pressures on saltwater intrusion in coastal urban areas: effective adaptation for policy planning

ABSTRACT

This article examines the relative impacts of anthropogenic interventions and global climate change on the dynamics of saltwater intrusion in highly urbanized coastal aquifers. For this purpose, simulations of the impacts of sea-level rise and abstraction scenarios for the near future were undertaken for a pilot aquifer using a multi-objective 3D variable-density flow and solute transport model. We find that sea-level rise associated with climate change has less influence on the encroachment of salinity than anthropogenic abstraction, which has a more appreciable impact on saltwater intrusion through greater sensitivity to water consumption and seasonality.     

GGA-SIC Calculations for Electronic and Magnetic Study of CdS Alloys

Journal of Superconductivity and Novel Magnetism - Electronic and magnetic properties of CdS-based, doped by various transition metal elements (Ti, V, Cr, Mn, Fe, Co or Ni), dilute magnetic...     

A new inhomogeneous partially reflecting surface for Fabry‐Perot antenna to reduce side lobe level

In this article, an extension of the spatial filter method to study Fabry‐Perot antennas with homogeneous or inhomogeneous partially reflecting surface (PRS) of finite size is proposed. This tool was subsequently validated through the study of different Fabry‐Perot antennas, with homogeneous PRS and inhomogeneous GRadient‐INdex (GRIN) PRS that present very high side lobe level (SLL). Since they are due to structure truncation, a new inhomogeneous PRS to reduce the SLL is designed with the new analytical tool. The new inhomogeneous PRS for Fabry‐Perot antenna is characterized by simulations and measurements. Compared to the homogeneous PRS antenna, the proposed PRS allows a SLL reduction of 5 dB without decreasing the 14 dBi directivity.     

A novel 3D dual active contours approach

Pattern Analysis and Applications - This paper investigates a 3D novel dual active contours approach to segment multiple regions in medical images. The locally based segmentation approaches can...     

Dynamic array PIN:A novel approach to secure NFC electronic payment between ATM and smartphone

ABSTRACT

Near Field Communication (NFC) technology has been used recently for electronic payment between an Automated Teller Machine (ATM) and a Smartphone. It is threatened by several attacks that can steal the user personal data like the password or the Personal Identification Number (PIN). In this paper, we present Dynamic Array PIN (DAP), a novel approach for user authentication on a Smartphone that uses NFC electronic payment with an ATM. Our analysis and experimentation prove that this technique protects against thirteen different attacks and is cost-effective in terms of required hardware, authentication time, computing power and storage space.     

RaCH: A New Radial Cluster Head Selection Algorithm for Wireless Sensor Networks

Wireless Personal Communications - This paper presents a radial cluster heads selection mechanism for homogenous wireless sensor networks. It aims to ensure a good load balancing and enhance the...