The utilization of steel slag for industrial and construction purposes has gained significant attention in recent years due to its abundant availability and potential environmental benefits. This study explores the feasibility of utilizing steel slag as a coarse aggregate in concrete, aiming to determine the optimal replacement percentages for desired mechanical and structural properties. Experimental investigations were conducted, substituting steel slag for conventional coarse aggregate in varying proportions. The concrete mixtures were tested for compressive strength, flexural strength, workability, and other parameters. The results demonstrate the promising potential of incorporating steel slag as a partial replacement for coarse aggregate. The mixture with 30% steel slag replacement exhibited favorable strength properties and workability. Both compressive and flexural strengths showed significant improvement, highlighting the viability of steel slag as an alternative to conventional coarse aggregate. The findings provide valuable guidance for engineers, researchers, and decision-makers in the construction industry regarding the practical benefits and considerations of using steel slag in concrete mixtures. This utilization promotes resource efficiency, reduces environmental impact, and maintains or enhances the mechanical and workability properties of concrete.

Powder metallurgy methods, particularly ball milling, are up-and-coming in tuning metal matrix composite (MMC) properties. This study uses ball milling at various milling times to create an aluminum matrix composite (AMC) reinforced with magnetite nanoparticles. The milling time was optimized to create an AMC with favorable mechanical and magnetic properties, and its effect on magnetism, microstructure, and hardness was studied.

The present study describes the fabrication of molecularly imprinted (MI) magnetic beaded fibers using electrospinning. Rosmarinic acid was selected as exemplary yet relevant template during molecular imprinting. A “design of experiments” methodology was used for optimizing the electrospinning process. Four factors, i.e., the concentration of the biodegradable polymer (polycaprolactone), the applied voltage, the flow rate, and the collector distance were varied in a central composite design. The production process was then optimized according to the suitability of the beaded fibers during microrobot fabrication, actuation, and drug release. The optimum average fiber diameter of MI beaded fibers was determined at 857 ± 390 nm with an average number of beads at 0.011 ± 0.002 per µm². In vitro release profiles of the optimized MI beaded fibers revealed a lower burst rate and a more sustained release when compared to control fibers. Magnetic control of the MI beaded fibers was successfully tested by following selected waypoints along a star-shaped predefined trajectory. This study innovatively combines molecular imprinting technology with magnetic microrobots enabling targeted drug delivery systems that offer precise motion control via the magnetic response of microrobots along with selective uptake of a drug into the microrobot using MI beaded fibers in future.

Targeted drug delivery (TDD) systems have several advantages, especially with drugs having toxic side effects such as lornoxicam (LX) which shows high hepatotoxicity and nephrotoxicity, especially with long-term use. This work represents an attempt to control magnetic microspheres encapsulating LX and magnetite nanoparticles (MNPs) for potential targeted drug delivery of LX. Superparamagnetic nanoparticles were fabricated via the co-precipitation method and together with LX were encapsulated into polycaprolactone (PCL) microspheres through an oil-in-water (O/W) emulsion solvent evaporation method. The effects of changing the amount of drug, MNPs, and volume of the aqueous phase were investigated by preparing several microsphere formulations. Increasing the amount of encapsulated MNPs increased the magnetization of the microspheres without affecting the morphology. Doubling the volume of the aqueous phase resulted in a higher encapsulation efficiency and drug loading; 83.9% and 10.7%, respectively, while increasing the amount of drug had a negative effect on both drug loading and encapsulation efficiency. Drug release from the microspheres was successfully achieved and showed a biphasic nature. A system of four planar coils was then used to magnetically control the movement of a cluster of capsules in a glycerin medium, as a simulation for the targeting process. The microspheres were successfully controlled to move in a U-turn path with sharp corners demonstrating their potential for TDD applications. Graphical Abstract

A two-step electrodeposition approach was applied to deposit Sn/C layers on a Ni foam substrate. The first step was the deposition of the Sn layer using two electrodeposition modes (direct and pulsed electrodeposition) with different parameters (duty cycle, time on/off, and effective time). The second step was to deposit carbon on the Sn layer by direct electrodeposition. The surface morphology, chemical composition, and phases of deposited layers were investigated and the electrochemical behavior of Sn/Ni and C/Sn/Ni anodes was characterized. The pulsed electrodeposition technique with a lower duty cycle (15% duty cycle with time ratio t _on / _off = 3/17 for 2 min) produced more uniform and compacted deposits, compared to the non-uniform and dendritic morphology obtained after high duty cycles (50%) as well as direct electrodeposition. After the direct electrodeposition of carbon on the pulsed electrodeposited Sn, a uniform layer containing ~ 10% C, 38% Sn, 45% Ni, and 7% O, was detected. Analysis of this layer confirmed the presence of Ni, Sn, and amorphous C. Electrochemical characterization showed that the C/Sn/Ni anodes with a 94 Ω polarization resistance, a 0.105 V/decade anodic Tafel slope and 0.202 V/decade cathodic Tafel slope manifested the highest apparent and intrinsic catalytic activities. The peak current for the C/Sn/Ni samples was higher than the peak current for the Sn/Ni samples at all scan rates, indicating higher electrochemical reactivity. The linear relationship between the peak current and the scan rate's square root suggests that diffusion controls the charge transfer process.