Silicene Nanoribbons on an Insulating Thin Film

Silicene, a new 2D material has attracted intense research because of the ubiquitous use of silicon in modern technology. However, producing free-standing silicene has proved to be a huge challenge. Until now, silicene could be synthesized only on metal surfaces where it naturally forms strong interactions with the metal substrate that modify its electronic properties. Here, the authors report the first experimental evidence of silicene nanoribbons on an insulating NaCl thin film. This work represents a major breakthrough, for the study of the intrinsic properties of silicene, and by extension to other 2D materials that have so far only been grown on metal surfaces.     

A Novel Speech Enhancement Method Using Fourier Series Decomposition and Spectral Subtraction for Robust Speaker Identification

Wireless Personal Communications - This paper presents a novel speech enhancement approach by combining Fourier series expansion and spectral subtraction. This approach is implemented in speaker...     

Effect of Annealing on the Dark and Illuminated I(V ) Characterization of a ZnO:Ga|Cu2O Hetero-Junction Prepared by Ultrasonic Spray System

Semiconductors - This paper presents the Ultrasonic Spray Pyrolysis system fabrication of gallium-doped zinc oxide (ZnO:Ga)|cuprous oxide (Cu2O) thin film hetero-junction. The deposition parameters...     

Benchmarking of lightweight cryptographic algorithms for wireless IoT networks

Wireless Networks - Cryptographic algorithms that can provide both encryption and authentication are increasingly required in modern security architectures and protocols (e.g. TLS v1.3). Many...     

3HA: Hybrid Hole Healing Algorithm in a Wireless Sensor Networks

In wireless sensor networks (WSNs), the appearance of coverage holes over a large target field is mostly possible. Those holes reduce network performance and may affect the network efficiency. Several approaches were proposed to heal coverage holes in WSNs, but they still suffer from some weaknesses. In this paper we suggest a distributed algorithm, named hybrid hole healing algorithm (3HA), to find the minimum effective patching positions to deploy additional nodes to cover the holes. A hole manager node of each hole is responsible for operating the 3HA algorithm which requires two phases. The first phase finds all candidate patching positions using a Voronoi diagram. It takes all Voronoi vertices within the hole as the initial patching positions list. The second phase reduces as much as possible this list based on integer linear programming and on a probabilistic sensor model. The 3HA algorithm repeats the above phases in rounds, until all Voronoi vertices are covered. Simulation results show that our solution offers a high coverage ratio for various forms and sizes of holes and reduces the number of additional sensors when compared to some algorithms like the Perimeter-based, the Delaunay triangulation-based, the Voronoi-based, and the Trees-based coverage hole healing methods.

     

Numerical study of elliptical cracks in cylinders with a thickness transition

The paper deals with elliptical cracks in a cylinder with a thickness transition. This structure is an assembly of two cylinders of thickness t and t₂ (t<t₂). In the transition zone, the thickness varies linearly. The purpose is to check whether tabulated data used for SIF calculations in a cylinder of uniform thickness t can be used for the cylinder with a thickness transition. A comparative study is made on the effect of a crack in a cylinder with a thickness transition and in a uniform thickness cylinder. Loads considered are pure tensile stress and bending moment. A numerical analysis was performed considering elastic behaviour at the crack tip. A crack mesh was designed and validated for 3D models. The results show that SIF calculations in the transition assuming a uniform thickness cylinder are conservative but not precise. The comparative study shows that the cylinder with a thickness transition is more vulnerable to a defect.     

Surface damage of poly(methylmethacrylate) under fretting loading

The initial fretting damage in a glass/PMMA contact was investigated by means of experiments and numerical (F.E.M.) simulations. Both micro-crack nucleation at the contact edges and particle detachment were identified on the PMMA's surface. Micro-crack initiation was related to the combination of high tensile stresses and positive hydrostatic pressures which are known to enhance crazing. During the early stages of the fretting tests, the distribution of the detached particles within the contact was correlated to the spatial distribution of the cumulative interfacial energy dissipated by friction. As the number of cycles was increased, it was observed that detached particles moved toward the middle of the contact. On the basis of FEM simulations, this particle displacement within the contact was attributed to the existence of differential micro-displacements during the fretting cycle.     

Iterative Methods for Solving the Neutron Transport Equation in 1-D Spherical Geometry

In this note, we propose an iterative methods technique for solving the neutron transport equation in 1-D spherical geometry. More precisely we analyze the theoretical and numerical aspect of Jacobi and Gauss-Siedel algorithms in an infinite dimension, and compare there with the classical method. These algorithms are based on a splitting of the collision operator taking into account the characteristics of the transport operator. One of the advantages of these algorithms is that give a good rate of convergence, and they are independent of the discretization chosen for the neutron transport equation.     

Synthesis of MIL-101@g-C<Subscript>3</Subscript>N<Subscript>4</Subscript> nanocomposite for enhanced adsorption capacity towards CO<Subscript>2</Subscript>

MIL-101@g-C₃N₄ nanocomposite was prepared by solvothermal synthesis and used for CO₂ adsorption. The parent materials (MIL-101 and g-C₃N₄) and the MIL-101@g-C₃N₄ were characterized by X-ray diffraction, argon adsorption/desorption, Fourier transform infrared spectroscopy, thermal analysis (TG/DTA), transmission electronic microscopy, and Energy-dispersive X-ray spectroscopy. The results confirmed the formation of well-defined MIL-101@g-C₃N₄ with interesting surface area and pore volume. Furthermore, both MIL-101 and MIL-101@g-C₃N₄ were accomplished in carbon dioxide capture at different temperatures (280, 288, 273 and 298 K) at lower pressure. The adsorption isotherms show that the nanocomposite has a good CO₂ adsorption affinity compared to MIL-101. The best adsorption capacity is about 1.6 mmol g^?1 obtained for the nanocomposite material which is two times higher than that of MIL-101, indicating strong interactions between CO₂ and MIL-101@g-C₃N₄. This difference in efficacy is mainly due to the presence of the amine groups dispersed in the nanocomposite. Finally, we have developed a simple route for the preparation of an effective and new adsorbent for the removal of CO₂, which can be used as an excellent candidate for gas storage, catalysis, and adsorption.     

Electrodeposition of lead dioxide on Fe electrode: application to the degradation of Indigo Carmine dye

Journal of Applied Electrochemistry - The modification of an iron electrode was carried out according to the following two steps. In a first step, a cathodic reduction is performed to form a film...