In this study, the effect of waste glass on the mechanical properties of concrete was examined by conducting a series of compressive strength, splitting tensile strength and flexural strength tests. According to this aim, waste glass powder (WGP) was first used as a partial replacement for cement and six different ratios of WGP were utilized in concrete production: 0%, 10%, 20%, 30%, 40%, and 50%. To examine the combined effect of different ratios of WGP on concrete performance, mixed samples (10%, 20%, 30%) were then prepared by replacing cement, and fine and coarse aggregates with both WGP and crashed glass particles. Workability and slump values of concrete produced with different amounts of waste glass were determined on the fresh state of concrete, and these properties were compared with those of plain concrete. For the hardened concrete, 150 mm × 150 mm × 150 mm cubic specimens and cylindrical specimens with a diameter of 100 mm and a height of 200 mm were tested to identify the compressive strength and splitting tensile strength of the concrete produced with waste glass. Next, a three-point bending test was carried out on samples with dimensions of 100 × 100 × 400 mm, and a span length of 300 mm to obtain the flexure behavior of different mixtures. According to the results obtained, a 20% substitution of WGP as cement can be considered the optimum dose. On the other hand, for concrete produced with combined WGP and crashed glass particles, mechanical properties increased up to a certain limit and then decreased owing to poor workability. Thus, 10% can be considered the optimum replacement level, as combined waste glass shows considerably higher strength and better workability properties. Furthermore, scanning electron microscope (SEM) analysis was performed to investigate the microstructure of the composition. Good adhesion was observed between the waste glass and cementitious concrete. Lastly, practical empirical equations have been developed to determine the compressive strength, splitting tensile strength, and flexure strength of concrete with different amounts of waste glass. Instead of conducting an experiment, these strength values of the concrete produced with glass powder can be easily estimated at the design stage with the help of proposed expressions.

Coal ash-based geopolymers with mine tailings addition activated with phosphate acid were synthesized for the first time at room temperature. In addition, three types of aluminosilicate sources were used as single raw materials or in a 1/1 wt. ratio to obtain five types of geopolymers activated with H₃PO₄. The thermal behaviour of the obtained geopolymers was studied between room temperature and 600 °C by Thermogravimetry-Differential Thermal Analysis (TG-DTA) and the phase composition after 28 days of curing at room temperature was analysed by X-ray diffraction (XRD). During heating, the acid-activated geopolymers exhibited similar behaviour to alkali-activated geopolymers. All of the samples showed endothermic peaks up to 300 °C due to water evaporation, while the samples with mine tailings showed two significant exothermic peaks above 400 °C due to oxidation reactions. The phase analysis confirmed the dissolution of the aluminosilicate sources in the presence of H₃PO₄ by significant changes in the XRD patterns of the raw materials and by the broadening of the peaks because of typically amorphous silicophosphate (Si–P), aluminophosphate (Al–P) or silico-alumino-phosphate (Si–Al–P) formation. The phases resulted from geopolymerisation are berlinite (AlPO₄), brushite (CaHPO₄∙2H₂O), anhydrite (CaSO₄) or ettringite as AFt and AFm phases.

This research investigates the two different hybrid nanofluid flows between two parallel plates placed at two different heights, $y_0$and $y_h$, respectively. Water-based hybrid nanofluids are obtained by using $A{l}_2{O}_3$, $Ti{O}_2$ and $Cu$ as nanoparticles, respectively. The upper-level plate is fixed, while the lower-level plate is stretchable. The fluid rotates along the y-axis. The governing equations of momentum, energy and concentration are transformed into partial differential equations by using similarity transformations. These transformed equations are grasped numerically at MATLAB by using the boundary value problem technique. The influence of different parameters are presented through graphs. The numerical outcomes for rotation, Nusselt, Prandtl, and Schmidt numbers are obtained in the form of tables. The heat transfer rate increases by augmentation in the thermophoresis parameter, while it decays by increasing the Reynolds number. Oxide nanoparticles hybrid nanofluid proved more efficient as compared to mixed nanoparticles hybrid nanofluid. This research suggests using oxide nanoparticles for good heat transfer.

This study aims to evaluate the corrosion resistance of carbon steel, used for carabiners manufacturing, coated with three different types of phosphate layer. The phosphate layers have been obtained by phosphate conversion coating with three different types of phosphate solutions: zinc-based solution, zinc-iron-based phosphate solution, and manganese-based phosphate solution. Additionally, the test was performed on zinc phosphate samples impregnated with molybdenum bisulfate-based oil and zinc phosphate samples further coated with a layer of elastomer-based paint. Considering the areas where the carabiners are used (civil engineering, navigation, oil industry, rescue operations, etc.), the corrosive environments studied are rainwater, Black Sea water, and fire extinguishing solution. The structure of the deposited layers was studied by scanning electron microscopy, while the interface structure between the alloy and corrosive environment was analyzed by electrochemical impedance spectroscopy. According to this study, the corrosion resistance of zinc-based phosphate coated samples and zinc/iron-based phosphate coated samples is higher than that of the studied carbon steel samples, despite the corrosion environment. Also, the most aggressive corrosion environment was the fire extinguishing solution.

Joining immiscible materials such as copper and stainless steel together is a significant concern due to distinct mechanical and metallurgical properties across the joint line, such as melting points, the coefficient of linear thermal expansion, and thermal conductivity. The joint properties of copper to stainless steel welds are in great demand for various mechanical components of the international thermonuclear experimental reactor, ultra-high vacuum system, plan wave linear-accelerator or linac structure, and heat exchanger. These dissimilar-metals joints offer excellent flexibility in design and production, leading to a robust structure for many cutting-edge applications. Hence, the present article reviews the copper to stainless steel joining mechanism under different solid-state processing conditions. The present understanding says that defect-free strong joints between the dissimilar metals are systematically possible. Apart from this understanding, the authors have identified and highlighted the gaps in the research exploration to date. Moreover, a sustainable methodology to achieve a desirable weld of copper to stainless steel depends on favorable processing conditions.

High entropy alloy (HEA) involves the addition of five or more elements into the materials system. This provides a multidimensional configuration space that is limitless in terms of its properties and functions. Some high-entropy alloys have already been shown to have superior properties over conventional alloys, especially the CoCr-based HEA materials. Better high-entropy alloy applications may be discovered, especially in micro- and nano-level structures, hence the development of thin film/coating -based HEA materials. Therefore, in this review paper, we are aiming to provide recent studies on the thin film/coating-based high-entropy alloy on fundamental issues related to methods of preparation, phase formation and mechanical properties. We found that sputtering has been extensively used to grow thin-film-based HEAs as it allowed parameters to be controlled with homogeneous growth. The evolution from bulk to thin samples can also be observed with the mechanical properties has exceeded the bulk-based HEA expectations, which are high hardness, better interfacial bonding and tribological behaviour and higher corrosion resistant.