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A novel approach to enhancing the efficacy and surface quality of magnetic polishing involves the incorporation of a magnetic liquid circulation system for abrasive particle regeneration in conjunction with a circular Halbach array. The continuous renewal of abrasive particles within the polishing zone is realised through a conveyor belt that transports new abrasive particles into the polishing liquid solution. This formation of a continuously circulating polishing system ensures uninterrupted magnetic finishing processes and maintains stability throughout the polishing operation. This study extensively explores polishing force distribution, magnetic field distribution and abrasive grain behaviour in the polishing area facilitated by the magnetic liquid solution. The application of the proposed polishing processes to polymethyl methacrylate, an optical lens material, aims to comprehend the characteristics and validate the feasibility of the polishing method. Key influencing factors in the magnetic polishing process, including abrasive grain size, magnetic particle, polishing distance and conveyor speed to surface quantity, are examined through experimental analysis. Results of the experimental polishing processes demonstrate that the utilisation of circular Halbach arrays with circulating abrasives produces a nanometric surface finish. Even in the polishing of polymethyl methacrylate with an initial rough surface (Ra = 464.895 nm), the process achieves an ultra-fine level with Ra below 9 nm without disruption in the material polishing processes of optical lenses.

In the pursuit of advancing the surface machining efficiency of Ti-6Al-4V material through magnetic polishing, this study introduces a new approach methodology. A novel approach integrates Magneto-Rheological Finishing (MRF) into a circulating system, employing a circular Halbach array to ensure a continuous and uniform flow of magnetic abrasives. Employing simulation and theoretical analysis, MRF polishing processes with the fluid dynamics of abrasive (SiO2) and magnetic particles (Fe3O4) during the finishing process of Ti-6Al-4V material using a circulating conveyor designed for the regeneration of abrasive particles. To investigate the impact of magnetic fluid distributions influenced by magnetic fields on the machining process, we meticulously conduct experimental analyses. The findings underscore that diminishing the working distance results in an expanded distribution range of magnetic abrasive fluid on the conveyor belt. Consequently, this induces a noteworthy variation in impact positions on the workpiece surface, leading to an increased exposed area. A pivotal outcome of this study is the observed augmentation in machining quality and efficiency. Remarkably, the surface roughness of the Ti-6Al-4V workpiece undergoes a substantial improvement, diminishing from an initial Ra = 431.1 nm to an impressive Ra = 39.6 nm within a 30-minute timeframe. [ABSTRACT FROM AUTHOR]

The recovery of metals from discarded mobile phones has been of interest due to its environmental and economic benefits. This work presents a simple and effective approach for leaching copper (Cu) from the printed circuit boards of discarded mobile phones by combining ultrasound and ozone approaches. The X-ray diffraction (XRD) technique and Fourier-transform infrared spectroscopy (FT-IR) were used to characterize the solid phases, and inductively coupled plasma optical emission spectrometry (ICP-OES) was utilized to determine the concentration of metals in the liquid phases. The effects of several influential parameters, including ultrasound, ozone dose, HCl concentration, liquid/solid ratio, temperature, and reaction time on the leaching efficiency were investigated. The results showed that the optimal conditions for Cu leaching included an ozone dose of 700 mg/h, HCl concentration of 3.0 M, liquid/solid ratio of 8, and temperature of 333 K. Under optimal conditions, about 99% of Cu was leached after 180 min. The shrinking core model was used to analyze the kinetics of the Cu leaching process, and the results showed that the surface chemical reaction governs this process. The activation energy of the leaching reaction, calculated using Two-Point form of the Arrhenius equation, was 10.852 kJ mol−1. [ABSTRACT FROM AUTHOR]

Spinal cysticercosis is a rare and severe cysticercosis complication. The pathology is from the inflammatory reaction and granuloma formation around the eggs, which cause focal neurological deficits. Because of the rarity of this condition, diagnosis may be delayed and confused with other myelopathies such as neoplasms or myelitis. We report a 42-year-old woman with low back pain and paraplegia. Magnetic resonance imaging showed a lesion in the spinal canal at the level of L4/L5 that was toward the diagnosis of myelitis. The patient underwent an open biopsy, and the result was granulomatosis caused by cysticercosis. The patient was then given an anticysticercosis medication and gradually recovered.