Biological Performance of Calcium Pyrophosphate‐coated Porous Alumina Scaffolds

The present work aims at synthesis and study the bioactivity of porous alumina scaffolds coated with calcium pyrophosphate. Characterization of the formed calcium pyrophosphate and the coated scaffolds was assessed by X‐ray diffraction analysis and scanning electron microscope examinations. The in vivo studies revealed the ability of the porous scaffolds to regenerate bone tissue in femur defects of albino rats. Histological analysis showed that the defect is almost entirely filled with new bone. The formed bone is characterized as a mature bone. The produced bone grafts are intended to be used as bone substitute or bone filler.     

Laser induced fluorescence spectroscopy of aromatic species produced in atmospheric sooting flames using UV and visible excitation wavelengths

In this work, laser induced fluorescence (LIF) has been applied to probe PAHs in two atmospheric sooting flames: a premixed flat flame of methane and a Diesel turbulent spray one. Different laser excitation wavelengths have been used. UV excitations at 266 and 355 nm have been operated from the fourth and the third harmonic frequencies of an Nd: YAG laser while visible excitations were emitted by an OPO pumped by the third harmonic of the YAG laser.     

Optimizing electrochemical performance of sonochemically and hydrothermally synthesized cobalt phosphate for supercapattery devices

The supercapattery (hybrid energy storage device) has procured miraculous heed for their significant electrochemical performance, constitute combine features of supercapacitor (prodigious power density) and batteries (substantial energy density), still crave for electrode material with better electrochemical conduct. Here, cobalt phosphate ((Co₃(PO₄)₂) nanostructures were synthesized using sonochemical and hydrothermal approach. The SEM, XRD, and EDX were employed to explore surface morphology, crystal structure, and elemental analysis respectively of as synthesized nanomaterials. The electrochemical performance was evaluated in two and three electrode assembly. The maximum specific capacity of 285 C g^-1 at 3 mV/s and 221 C g^-1 at 4.1 A g^-1 has been obtained by sonochemically synthesized nanomaterial (S1). This electrode material with optimum electrochemical performance was further investigated for supercapattery application. Asymmetric device was fabricated, comprising activated carbon as negative and S1 as positive electrode material. The supercapattery device exhibits a specific capacity of 147.2 C g^-1 bearing an outstanding energy density of 34.8 Whkg^?1 with a power density of 425.0 W kg^-1 at 0.5 A g^-1. The device was found to have a remarkable power density of 6800.0 W kg^-1 while retaining an energy density of 10.0 Whkg^?1 with exceptional capacity preservation of 87.2% after 10,000 consecutive GCD cycles even at 8.0 A g^-1. The device performance was further explored in terms of capacitive and diffusion controlled processes and found to have a maximum capacitive contribution of 63.8% at 100 mV s^-1. The sonochemical method was found to be the optimal route to synthesize nanomaterials for energy storage applications.     

On the interaction between transformation induced plasticity and the austenitic stainless steel anisotropy (AISI 304) under shear loading path

It is well known that for the AISI 304 austenitic stainless steel some parameters such as temperature, strain rate, material anisotropy and loading path are the main factors which strongly affect the kinetic of transformation induced plasticity (TRIP) in this material. In literature, tensile and compression tests represent the commonly experimental tools studied on this material. Under such type of loading, dissymmetry plastic behavior was obtained due to the martensitic kinetic evolution.The aim of the present work is to highlight the role of the TRIP phenomenon on the initial material anisotropy of the AISI 304 material using appropriate experimental framework. The cross-coupled effect of the phase transformation on initial anisotropy is studied through special loading test (simple shear test (SST)) conducted at various temperatures.     

Influence of hydrogen and carbon monoxide on reduction behavior of iron oxide at high temperature: Effect on reduction gas concentrations

The purposes of this study are to reduce Fe₂O₃ using hydrogen (H₂) and carbon monoxide (CO) gases at a high temperature zone (500 °C–900 °C) by focusing on the influence of reduction gas concentrations. Reduction behavior of hematite (Fe₂O₃) at high temperature was examined using temperature programmed reduction (TPR) under non-isothermal conditions with the presence of 10% H₂/N₂, 20% H₂/N₂, 10% CO/N₂, 20% CO/N₂ and 40% CO/N₂. The TPR_CO results indicated that the first and second reduction peaks of Fe₂O₃ at a temperature below 660 °C appeared rapidly when compared to TPR_H2. However, TPR_H2 exhibited a better reduction in which Fe₂O₃ entirely reduced to Fe at temperature 800 °C (20% H₂) without any remaining of wustite (FeO) whereas a temperature above 900 °C is needed for a complete reduction in 10% H₂/N₂, 10% and 20% CO/N₂. Furthermore, the reduction of hematite could be improved when increasing CO and H₂ concentrations since reduction profiles were shifted to a lower temperature. Thermodynamic calculation has shown that enthalpy change of reaction (ΔHr) for all phases transformation in CO atmosphere is significantly lower than in H₂. This disclosed that CO is the best reductant as it is a more exothermic, more spontaneous reaction and able to initiate the reduction at a much lower temperature than H₂ atmosphere. Nevertheless, the reduction of hematite using CO completed at a temperature slightly higher compared to H₂. It is due to the presence of an additional carburization reaction which is a phase transformation of wustite to iron carbide (FeO → Fe₃C). Carburization started at the end of the second stage reduction at 600 °C and 630 °C under 20% and 40% CO, respectively. Therefore, reduction by CO encouraged the formation of carbide, slower the reduction and completed at high temperature. XRD analysis disclosed the formation of austenite during the final stage of a reduction under further exposure with high CO concentration. Overall, less energy consumption needed during the first and second stages of reduction by CO, the formation of iron carbide and austenite were enhanced with the presence of higher CO concentration. Meanwhile, H₂ has stimulated the formation of pure metallic iron (Fe), completed the reduction faster, considered as the strongest reducing agent than CO and these are effective at a higher temperature. Proposed iron phase transformation under different reducing agent concentrations are as followed: (a) 10% H₂, 20% H₂ and 10% C; Fe₂O₃ → Fe₃O₄ → FeO → Fe, (b) 20% CO; Fe₂O₃ → Fe₃O₄ → FeO → Fe₃C → Fe and (c) 40% CO; Fe₂O₃ → Fe₃O₄ → FeO → Fe₃C → Fe → F,C (austenite).     

Tailoring the structural,magnetic and dielectric properties of Ni-Zn-CdFe2O4 spinel ferrites by the substitution of lanthanum ions

In this paper, we have tailored the structural, magnetic and dielectric properties of Ni_0.5Zn_0.3Cd_0.2Fe_2-yLa_yO₄ (y?=?0.0–0.21) nano-structured spinel ferrites by the substitution of La³⁺ ions. The investigated samples were synthesized by Sol-gel auto-combustion method and were characterized using XRD, SEM, VSM, FTIR and dielectric measurements. Single phase nanostructure formation of synthesized material was confirmed by XRD analysis. The effect of La³⁺ ions on crystallite size, grain size, lattice constant and bulk densities was calculated and it was found that lattice constant first increased upto concentration y?=?0.105 then decreased with further substitution of dopant ions. FTIR results for all synthesized samples demonstrated two absorption bands at υ₁ =?540.8?cm^?1 and υ₂ =?490.8?cm^?1 corresponds to tetrahedral and octahedral sites of spinel structure respectively. With the increase in La³⁺ ions concentration, saturation magnetization and remanence both found to be decreased down to lowest M_s value of 34.1?emu/g which is not yet reported in the literature according to best of our knowledge. Dielectric results showed that by decreasing frequency, both dielectric loss and dielectric constant decreases. AC conductivity has two regions, at low frequency region ac conductivity increases while at high frequency region, it decreases with increasing frequency. The measured results for all synthesized nano-ferrites suggested that synthesized nanoferrites are recommended for high frequency and microwave absorbing applications.     

Crystal Structure and Magnetic Properties in B-Site-Disordered La1.75Ca0.25MnMO6 (with M = Ti and Fe) Double Perovskites

Journal of Superconductivity and Novel Magnetism - Double perovskite La1.75Ca0.25MnMO6 (with M?=?Ti and Fe) systems were elaborated employing a solid-state reaction method. The...     

Radio interference challenges in a multiprotocol compact RF hardware platform for home and building automation applications

In the field of smart home and smart building, there is a wide range of products using various proprietary and open standards for their interconnection. However, the coexistence of those standards imposes serious constraints because of the inherent nature of the radio frequency propagation. A way to investigate this issue is to study the interferences in a compact hardware platform/box in which several radio transceivers work side by side, potentially causing interference and radio link degradation due to antennas coupling. To achieve this analysis and predict the radio issues, a simulation tool was developed, and several experimental tests were conducted indoors and outdoors to validate the simulation model. The compact platform investigated consists of multiprofile KNX‐RF modules for home automation and smart grid control, and a radio alarm module for security needs. Simulations were conducted using MATLAB/Simulink, which are based on a calculation of bit error rate according to the signal to noise ratio in order to deduce the radio coverage range in different interference scenarios. The simulation tool developed was optimized to match the behavior of a specific transceiver commonly used for KNX‐RF devices. Yet the tool can be adapted to simulate other kinds of transceivers. Furthermore, the methodology applied to evaluate the cross‐technology interference can be extended to other technologies like Wi‐Fi, ZigBee, and EnOcean.     

Effect of thermal treatments on the degradation of antibiotic residues in food

The thermal stability of antibiotics commonly detected in food is reviewed. To quantify degradation, 2 major techniques have been reported: liquid chromatography-based methods and microbiological tests. As the degradation products may also display some antimicrobial activity, microbiological tests may not be considered accurate analytical methods for quantifying antibiotic residues' degradation. Degradation percentages are summarized for different antibiotics and for various media (water, oil, milk, and animal tissues). Studies presented in the literature confirm that the thermal degradation of β-lactams, quinolones, sulfonamides, and tetracyclines can be described using a first-order kinetic model. Degradation rates, k, derived for this model for liquid matrix (water) at 100 °C, followed the general trend amongst antibiotic classes: β-lactams = tetracyclines (most heat-labile) > lincomycin > amphenicols > sulfonamides > oxfendazole > levamisole (most heat-stable). Although thermal processing results in a decrease in the concentration of parent antibiotic residues, degradation by-products have not been properly characterized to date. As some of these products were shown to be hazardous, further investigation is needed to determine their impact on food safety and human health. It is therefore currently difficult to definitively conclude whether or not antibiotic degradation during food processing is necessarily beneficial in terms of food safety.