Structure cristalline de l'orthophosphate monoacide de cuivre monohydrate CuHPO4,H2O

Monophosphate hydrogen copper monohydrate : CuHPO₄,H₂O is monoclinic, space group $\text{P}\text{2}{}_1\text{a}$. The unit cell parameters are : a = 8.63(6), b = 6.35(3), $\text{c}\text{= 6.82(5)}\text{A}\text{?}$, β = 94.14(6°) and Z = 4. The crystal structure has been determined with 1249 independent reflexions and refined to a final R value of 2.9%. The crystal is built up of PO₄ tetrahedron and CuO₆ octahedron deformed by Jahn-Teller effect which are linked to form a three dimensional network.Based on the inter-ionic distances between Cu^II and O^2? in the recently determined structures of monoarsenates or phosphates, we give a value for the effective ionic radius of copper II.     

Encryption Based Strategy to Overcome the Problem of Pilot Contamination Within Multi-cellular Massive MIMO Systems

The problem of inter-cell interferences keeps its site as the most challenging constraint that faces the massive multi-input multi-output (M-MIMO) technology. This constraint, known as the problem of pilot contamination (PC), is a direct result of reusing the same set of orthogonal pilot sequences (OPSs) across several cells, due to the scarcity of available pilot resources, compared to the number of the user equipments (UEs) that must be served, the reuse of the same OPSs within different cells is unavoidable. Accordingly, assigning the available OPSs to the UEs should be managed to address the PC problem. To reach that goal, a new decontaminating strategy is proposed herein, which is referred to as the ENCryption-based decontaminating strategy (ENC). The ENC strategy is based on injecting some recognition pilot symbols within the pilot sequence of the UEs; hence, the base stations become able to distinguish between the desired pilot signals from the undesired ones, therefore, the quality of servicecan be enhanced, furthermore, the proposed ENC strategy is of low computational complexity compared to the existing strategies.

     

Performance Improvement of Optical Multiple Access CDMA Network Using a New Three-Dimensional (Spectral/Time/Spatial) Code

Wireless Personal Communications - In this paper, a novel code named three dimensional single weight zero cross correlation (3D-SWZCC) code has been developed for spectral/time/spatial (S/T/S)...     

A review on hydrogen generation from the hydrolysis of sodium borohydride

Hydrogen is a promising alternative energy source to conventional fuels, including fossil fuel. Thus, several methods were reported for the generation of hydrogen. This review provided a comprehensive bibliometric analysis of the publications that focus on the hydrolysis or hydrolytic dehydrogenation of sodium borohydride (NaBH₄). Surveying articles in the literature showed a promising future for this technology, although some challenges lie ahead. The process can be reversible via the regeneration of the reaction by-product (NaBO₂?2H₂O or NaBO₂?4H₂O). The key parameters affecting the hydrolysis reaction of aqueous NaBH₄ were also summarized. The analysis of the publications indicated that hydrogen production techniques need further investigations to be competitive and for renaissance of the current applications. This review also presented concerns behind the commercialization of the generation of hydrogen gas using the hydrolysis of NaBH₄. Several materials have been reported for hydrogen generation, but thus far, no single material can simultaneously meet all the required criteria for mobile applications. Researchers and political decision-makers should manage the progress and open new channels for commercialization purposes. The hydrolysis of NaBH₄ is promising for several applications, including material science, environmental fields, and energy-based applications.     

Multidentate Cyclohexylphosphonic Acid as Corrosion Inhibitor for Structural Steel in 3.5% NaCl Solution: An Experimental and Computational Study

Protection of Metals and Physical Chemistry of Surfaces - The inhibition effect of cyclohexylphosphonic acid (CHPA) on the corrosion of structural steel (EN 10027) in 3.5% sodium chloride solution...     

Analysis and prediction of woven compression bandages properties

Compression bandage (CB) as a porous material consists of elastic textile that exerts pressure on muscles. Three common types of woven CBs are evaluated. Uniaxial stresses of the input yarns and the produced bandage will be tested. This work presents a new method to predict optimum required tension when applying CB on lower leg ankle and mid-calf positions. Experimental measurements and data analysis using NIS software enable to analyze and calculate the bandage porosity during extension using high speed camera. Practical bandage pressure is measured using PicoPress tester. The obtained results will be compared with theoretical compression forces calculated by a modified Laplace’s law equation which predicts graduated compression ranging from 27 to 72?mmHg at the ankle, tapering to 18–8?mmHg below the knee. Results confirm that theoretical pressure is not exactly consistent with practical compression.     

Capacity analysis for LOS millimeter–wave quadrature spatial modulation

Capacity analysis for millimeter-wave (mmWave) quadrature spatial modulation (QSM) multiple-input multiple-output (MIMO) system is presented in this paper. QSM is a new MIMO technique proposed to enhance the performance of conventional spatial modulation while retaining almost all its inherent advantages. Furthermore, mmWave utilizes a license-free wide-bandwidth spectrum and is a very promising candidate for future wireless systems. Detailed and novel analysis of the mutual information and the capacity for line of sight (LOS) mmWave-QSM system are presented in this study. The conditions under which theoretical capacity can be achieved are derived and discussed. Also, mmWave channel design is conducted and a novel algorithm is proposed to overcome existing limitation for unbalanced MIMO configurations, i.e., when the number of receive antennas is less than that of the transmit antennas. Monte Carlo simulation results are provided to corroborate derived formulas. It is shown that significant performance enhancements can be achieved under different system and channel configurations.     

Optimizing the Antibacterial Activity of Iron Oxide Nanoparticles Using Central Composite Design

This work aims to optimize the antibacterial activity of iron oxide nanoparticles (IONPs) against both Gram-positive and Gram-negative bacteria. IONPs were greenly biosynthesized using Moringa oleifera leaves extract, and surface methodology (RSM) based on central composite design (CCD) was employed to investigate the combined effect of various experimental factors on the antibacterial activity of IONPs. The reaction and annealing temperatures besides precursor concentration were set as independent variables, while the antibacterial activity was set as a response to obtain the optimal conditions that maximizes IONPs antibacterial activity. Different characterization techniques such as UV–Vis, FTIR, XRD, SEM, and EDX were employed to study the properties of the biosynthesized nanoparticles. Meanwhile, the antibacterial activity was tested using the disk diffusion method. The characterizations results have confirmed the biosynthesis of Hematite (α-Fe₂O₃) nanoparticles of rhombohedral structure. The generated model has exhibited predicted values very close to the actual proving its validity to analyze and optimize the studied process. The model indicated that all the investigated parameters and their interactions have significantly affected IONPs antibacterial activity. An optimal antibacterial activity was achieved when biosynthesis factors at their lower levels (? 1). Furthermore, the effect of IONPs size on the antibacterial activity was studied and the results shown that the latter is significantly related to the nanoparticles size.

Graphical Abstract