Materials Letters: X最新文献

Despite extensive studies on electrorefining to remove impurities from copper production units, bleeding electrolytes is the most popular method for controlling impurities due to low operating costs. A controlled cooled-reheat cycle was used to remove impurities in industrial electrolytes of Khatoon Abad copper company. Phase identification and physical study were done by the XRD, SEM, TEM, and FTIR techniques. The results confirmed the possibility of the removal of 23 wt% Ni, 26 wt% Sb, 2.4 wt% As and convention of 6 wt% of As⁵⁺ to As³⁺ at cooled-reheat cycle.

Hot pressing of pure Ti and cast iron under vacuum formed a ∼15 µm wide TiC-layer through the thermo-reactive diffusion process. Nanoindentation testing of the TiC-layer revealed average hardness and elastic modulus values of ∼35 GPa and ∼400 GPa, respectively. High-resolution indentation mapping indicated hardness change across the boundary with peak values observed within the TiC-layer. Solid state high temperature diffusion holds significant potential for developing uniform hard coatings on pure Ti/Ti-alloys.

Alumina deposit was produced by metalorganic chemical vapour deposition process on a NiCoCrAlY superalloy substrate. Low frequency injection in the range 5–10 Hz was used to feed the Aluminium Tri-isopropoxide precursor into a deposit chamber holding at 400 °C of temperature. Both scanning electron microscopy and X-ray diffraction analysis were accomplished to characterize the deposited alumina. Topographic images show an alumina deposit roughness of Ra 35 nm measured by atomic force microscopy. An X-photon spectroscopy analysis of the alumina deposit was performed to identify both Al species and chemical analysis. Thermo-gravimetric analysis was conducted to assess the effect of deposited alumina on the superalloy.

A model to depict that it is possible to separate solid cobalt and copper from liquid Mg-Co-Cu mixtures is presented. The model aims to demonstrate how the application of solution thermodynamics concepts can help in depicting real processes.

Octacalcium phosphate (OCP) has attracted attention as a bone-repairing material with excellent bone regeneration ability, and F⁻ incorporation is expected to further promote bone formation. However, because OCP is easily converted to fluorapatite in an aqueous fluoride solution, it is difficult to incorporate a large amount of F⁻ while maintaining the crystalline structure of OCP. Therefore, in this study, we attempted to introduce F⁻ into OCP using an ionic liquid with high F⁻ concentration in a non-aqueous environment. OCP was incorporated with F⁻ in the form of ion pairs after treatment with an acetone solution of 1-ethyl-3-methylimidazolium tetrafluoroborate. The F⁻ content was approximately 9%, which was approximately 28 times greater than achieved in previous studies. The amount of OCP with F⁻ dissolved in acetate buffer was less than that of untreated OCP.

In the present research work, an aluminomagnesium hydrogel was synthesized via co-precipitation, organic solvent-based aging, and microwave irradiation drying. The synthesized hydrogel was used to remove methylene blue dye from aqueous solutions. The adsorption experiments at room temperature indicated a removal efficiency of 99.7% under an adsorbent dosage of 4 g/L and a duration of 30 min. The adsorbent regeneration tests also confirmed the reusability of the adsorbent for the removal of dye, so that after five regeneration cycles, the hydrogel exhibited a removal efficiency of more than 90% under the same conditions. Overall, the results confirmed that the synthesized aluminomagnesium hydrogel could be used as a promising dye scavenger for methylene blue.

An efficient dry electrode is required to effectively record the biopotential signals. This study proposes a dry electrode for ECG monitoring based on highly flexible, conductive, and antibacterial silver nanorods (AgNRs) grown via a novel glancing angle deposition and RGO-PDMS composite matrix. The fabricated electrode possesses good electrical conductivity and skin contact impedance between 70.1 ± 0.7 kΩ to 5.6 ± 1.7 kΩ for frequencies ranging from 40 Hz to 1 kHz, comparable to conventional Ag/AgCl wet electrodes. These electrodes give excellent quality ECG signals and do not cause skin irritation even after several hours of usage. They offer high skin compatibility and good signal quality, which are prominent features for cardiorespiratory monitoring.

An organic crystalline salt − 2,4-Diamino-6-methyl-1,3,5-triazin- 1-ium hydrogen oxalate (DMTO) has hydrogen interactions viz. NH⋯O, CH⋯O, NH⋯N and OH⋯O gives interesting vibrational effect. X-ray diffraction study reveals that DMTO is crystallized in triclinic centrosymmetric space group P-1 as expected. Structural as well as the vibrational spectra have been discussed on the basis of density functional theory (DFT) using B3LYP hybrid functional with the basis set 6–311++G(d,p). Acidic proton of the oxalic acid (OA) is transferred to 2,4-diamino-6-methyl-1,3,5-triazine (DAMT) and giving rise to singly protonated 2,4-diamino-6-methyl-1,3,5-triazinium ion.

Cobalt-copper-zinc ferrite (CoCuZnF) nanoparticles were synthesized using the precipitation method. The characterization of CoCuZnF was carried out using powder XRD, Raman, IR, UV–vis, and FEG-SEM. The TG-DSC data of NTO, and nNTO containing the catalyst was used to study the thermal decomposition behavior. Three non-isothermal methods were used to evaluate the kinetic parameters. The kinetics data suggests that incorporation of CoCuZnF additive can effectively decrease the high activation energy of NTO by ∼83–88 kJ mol⁻¹ and nNTO (∼205–216 kJ mol⁻¹). The decomposition of both NTO and nNTO was faster in the presence of CoCuZnF, suggesting its plausible use in the high explosive munitions containing NTO.

This paper presents results of application of Ultrasonic Waves UW in civil engineering. The measurement has been performed by ultrasonic reflection technique using a transducer with central frequency 0,5MHz. Several methods of analysis and signal processing have been applied to detect the position of reflections and to measure the time of flight between two echoes related to the reflection at the mortar interfaces. The experiments performed in the laboratory are carried to determine the ultrasonic velocity of the wave backscattered by samples. This allowed determining the ultrasonic velocity of UW in the mortar in order to deduce the durability of each mortar according to its microstructure. The objective is to make a comparative study of the various methods of analysis of the ultrasonic signals as: Continuous Wavelet Transform (CWT), Wigner Ville (WVD), Pseudo Wigner–Ville distribution (PWVD), Smoothed Pseudo Wigner–Ville Distribution (SPWVD) and Hilbert Transform (HT).