The nanoparticles of the magnetic core-shell Fe₃O₄@SiO₂ were produced using a modified Stöber approach and functionalized with (3-amino-propyl) APTES triethoxysilane and ethylene-diamine-tetra-acetic acid (EDTA). Magnetic nano adsorbents exhibit many attractive opportunities for different purposes due to their easy removal and possibility of reusing these nanoparticles. The ligands grafting was chemically stable and did not affect the morphology or substrate structure appreciably. APTES-EDTA microspheres were formed for the removal from aqueous solution solutions of trivalent rare earth elements ions since the REEs have a strong oxygen affinity. The advantages of the SiO₂ shell that covers the magnetite nanoparticles include lower specific weight and a larger grafting density compared to other surfaces, improving the resistance to acidic environments. Different techniques have described the particle size, morphology, precise surface area and surface alteration including Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), X-ray powder diffraction (XRD), and vibrating sample magnetometer (VSM). The results show that the Fe₃O₄ nanoparticles with an average particle size of 15 ± 3 nm were successfully synthesized at pH=11, at 25 °C temperature. Moreover, The nanoparticles prepared for Fe3O4 were coated with amorphous SiO2 and functionalized with amino and carboxylic groups.

Background: Although numerous studies have been conducted to investigate the acute effects of shoe drops on running kinematics and kinetic variables, their effects on muscle forces remain unknown. Thus, the primary aim of this study was to compare the muscle force, kinematics, and kinetic variables of habitually rearfoot runners with heel-to-toe drops of negative 8 mm shoes (minimalist shoes) and positive 9 mm shoes (normal shoes) during the running stance phase by using musculoskeletal modeling and simulation techniques. Methods: Experimental data of lower limb kinematics, ground reaction force, and muscle activation from 16 healthy runners with rearfoot strike patterns were collected and analyzed in OpenSim. Using Matlab, the statistical parameter mapping paired t-test was used to compare the joint angle, moment, and muscle force waveform. Results: The results revealed differences in the sagittal ankle and hip angles and sagittal knee moments between the different heel-to-toe drops of running shoes. Specifically, it showed that the negative 8 mm running shoes led to significantly smaller values than the positive 9 mm running shoes in terms of the angle of ankle dorsiflexion, ankle eversion, knee flexion, hip flexion, and hip internal and hip external rotation. The peak ankle dorsiflexion moment, ankle plantarflexion moment, ankle eversion moment, knee flexion moment, knee abduction moment, and knee internal rotation also decreased obviously with the minimalist running shoes, while the lateral gastrocnemius, Achilleas tendon, and extensor hallucis longus muscles were obviously greater in the minimalist shoes compared to normal shoes. The vastus medialis, vastus lateralis and extensor digitorum longus muscles force were smaller in the minimalist shoes. Conclusions: Runners may shift to a midfoot strike pattern when wearing negative running shoes. High muscle forces in the gastrocnemius lateral, Achilleas tendon, and flexor hallucis longus muscles may also indicate an increased risk of Achilleas tendonitis and ankle flexor injuries.

During this research work, the wear and friction properties of TiN/TiC coatings produced with different manufacturing parameters were investigated against steel and zirconium counterparts. The coatings, which were deposited on WC–Co substrate, were characterized based on their microstructure, phase composition, and microhardness. The tribological behavior of the coatings was examined in accordance with ASTM G99 and ASTM G133 standards using pin-on-disc tests with steel and zirconium counterfaces, while the adhesion of the coatings was investigated with a modified scratch test. According to the results obtained from the experiments, the use of zirconium counterpart is advantageous even for coatings produced with different microhardness and layer thickness using the CVD method. The results show that the change in the friction coefficient can be well traced with properly chosen parameters, thereby determining the wear resistance of the coating.

Nowadays, the construction industry is challenged not only by increasingly strict environmental regulations, but also by a shortage of raw materials and additives. It is critical to find new sources with which the circular economy and zero waste approach can be achieved. Promising candidates are alkali activated cements (AAC), which offer the potential to convert industrial wastes into higher added value products. The aim of the present research is to develop waste-based AAC foams with thermal insulation properties. During the experiments, pozzolanic materials (blast furnace slag, fly ash, and metakaolin) and waste concrete powder were used to produce first dense and then foamed structural materials. The effects of the concrete fractions, the relative proportions of each fraction, the liquid/solid ratio, and the amount of foaming agents on the physical properties were investigated. A correlation between macroscopic properties (strength, porosity, and thermal conductivity) and micro/macro structure was examined. It was found that concrete waste itself is suitable for the production of AACs, but when combined with other aluminosilicate source, the strength can be increased from 10 MPa up to 47 MPa. The thermal conductivity (0.049 W/mK) of the produced non-flammable foams is comparable to commercially available insulating materials.

A novel approach to investigate the oxidation behaviour of bilayer TiN/TiC coatings deposited on WC-Co substrate by CVD method was employed. Two coatings with different structures and mechanical properties were manufactured using different processing parameters. Energy dispersive X-ray analysis was utilized to monitor the elemental composition during oxidation tests at 800 ?C for up to 40min, which simulated the high temperature conditions experienced by the coated cutting tools. The obtained results demonstrated that the oxygen content increased significantly, reached ~68.8 at.%, while carbon and nitrogen contents decreased due to the formation of gaseous by-products. X-ray diffraction confirmed complete transformation of the TiN layer into rutile-TiO2 after 20min of oxidation. The microhardness of the coated samples significantly decreased due to the oxide formation and development of pores and cracks during the oxidation process. Tribological tests revealed a significant increase in the volume loss during dry sliding against zirconia counterpart after 20min of oxidation time. Moreover, surface colour of the oxidized coated samples changed from silver-white to grey-black with oxidation progression, enabling visual evaluation of oxidation damage.