Key Engineering Materials Vol. 1008

Abstract: As bridge structures have advanced, the demand for higher bearing capacity has increased. Castable Polyurethane Elastomeric Bearings have gained attention due to their strong load-bearing capacity and straightforward manufacturing process. This paper focuses on the development of a polyurethane seismic isolation bearing and examines its microscopic and mechanical properties. Additionally, a flexible strain sensor was created using polyurethane as the polymer substrate and multi-walled carbon nanotubes (MWCNT) as the conductive particles. The sensor's force-electric sensing behavior was systematically analyzed, and its effectiveness in monitoring the deformation of laminated isolation bearings was verified.

Abstract: Nanocomposites of tellurium and sodium nitrate were synthesized via a simple thermal dissolution of polycrystalline tellurium powder in nitric acid, followed by tellurium reduction in the presence of sodium dithionite solution. Thin solid films based on these composites have been fabricated and characterized. The morphology, composition and structure of the films were investigated by SEM, EDS, and XRD methods and the possible chemical reactions for the synthesis of relevant nanocomposites were formulated. It has been established that composites consist of nanowires with a diameter of ~100 nm and lengths up to 1,0 micrometers and nanoparticles of 100 ÷ 300 nanometers comprising about 35 at% Te and 7.0 at% of sodium nitrate. It is expected that nanocomposites synthesized via this method can be of interest in producing functional thin films, having both electronic and ionic conductivity.

Abstract: We have studied the impact of nanosized grains of copper oxides, grown by atomic layer deposition (ALD), on photocatalytic activity of thin titanium dioxide (TiO₂) films under visible-light irradiation. The size of grains and the crystal phase of copper oxide were controlled by the number of ALD deposition cycles. The x-ray diffraction and x-ray photoelectron measurements revealed preferential formation of CuO for a small number of deposition cycles, while Cu₂O forms preferentially for a larger number of cycles. The photocatalytic efficiency of pristine TiO₂ has been enhanced for copper oxide/TiO₂ structures in which the nanosized copper oxide grains do not cover the entire TiO₂ surface. At the same time, the large increase of the current measured across the copper oxide/TiO₂ structures is consistent with the charge transfer from copper oxide grains to TiO₂, essential for the observed increase of photocatalytic activity.

Abstract: Corrosion refers to the deterioration of both metal and non-metal objects caused by their electrochemical reactions with the environment around them. The objective of this study work is to investigate the corrosion characteristics of Aluminium that has been strengthened with leadwood particles. Aluminium and organic leadwood particles were combined through the process of smelting and stir-casting, using various weight ratios. Linear politization method was used to determine the corrosion rate. Taffel plots were used to determine the polarization potential and the corrosion current. The results indicated that Leadwood can be successfully used to reinforce and enhance the corrosion resistance of Aluminium. 2% leadwood reinforced sample was corroding at a rate of 1.3366mm/yr, an improvement of 37.5% to the parent Aluminium sample (2.1416mm/yr), while the 3% pulverized leadwood reinforce sample’s corrosion rate was 1.9053mm/yr (10.9% corrosion improvement).

Abstract: This study focused on cutting trace control for machining three-dimensional contours, such as molds, with high accuracy and efficiency. In this study, experiments were conducted to generate a honeycomb structure with hexagonal cutting marks and a lattice structure with square cutting marks in the cutting process of a two-blade ball-nose end mill using a runout adjustable holder, with the aim of adapting the cutting-mark control to the production level. In this study, the relationship between runout, machined surface, and cutting force is shown, and the effects of runout, honeycomb structure, and lattice structure on surface adsorption are investigated and evaluated for applications in the production field.

Abstract: The effectiveness of ultrasonic vibration polishing, a polishing method in which an abrasive wheel is vibrated perpendicular to the polishing direction, was investigated. A 3mm diameter cBN abrasive electroplated wheel (#800) was used as the abrasive wheel, and it was vibrated at a frequency of 38kHz and a maximum amplitude of 5.0µm (0-p). Truncation was also performed to make the abrasive grain height of the wheel uniform. Two types of truncation were performed: film lapping and PCD lapping, and the effects of truncation were investigated. Polishing experiments were performed on SKH51, and a comparison was made with conventional polishing and the effects of truncation. The results showed that ultrasonic vibration polishing using a truncated wheel improved the polishing efficiency and surface roughness.

Abstract: The recent development of computer-aided design/computer-aided manufacturing (CAD/CAM) systems has enabled unskilled workers to generate NC programs easily. However, determining the cutting conditions, which is crucial for machining, still relies on the knowledge and experience of the skilled workers. Therefore, this study aimed to discover tacit knowledge about cutting using data mining methods and construct a system to support unskilled workers. Given the recent progress in the practical use of barrel tools, this study attempts to predict the cutting conditions of barrel tools by utilizing catalog information on radius and ball end mills. First, the databases of all the tools were integrated. Next, new variables were introduced for highly accurate predictions. After verifying the validity of the new variables through cutting experiments, they were used to predict cutting conditions. It was found that the new variables could be used in the clustering process to achieve highly accurate predictions.

Abstract: In recent years, electronic devices have become lighter, thinner, shorter, smaller, and more multifunctional, driving advancements in drilling technologies. To meet the demands of electronic applications, this study proposes a drilling machine tool with a counterbalanced vibration control mechanism. In this study, machining experiments were conducted using a machine tool equipped with a left-right ball screw counterbalance mechanism during the step operation. Observations were made with a high-speed camera and a thermal camera, followed by examinations of the drill and holes after machining. As a result, significant findings regarding the drill tip temperature and runout were obtained. It was also confirmed that drill wear and runout affect machining quality.

Abstract: This study investigates the enhancement of solar still efficiency through the integration of a mini solar pond and reflective mirrors. Key variables affecting performance were identified: sodium chloride concentration, solar pond zone, and mirror angles. Four parameters were systematically varied across three levels and analyzed using an orthogonal array (L27). ​The optimal configuration was determined through Signal-to-Noise (S/N) ratio analysis, revealing that a concentration of 2.5 kg sodium chloride, a 75 cm solar pond zone, and specific mirror angles significantly improved distilled output. ​ It endeavors to uncover the significant factors contributing to the enhanced efficiency of the hybrid solar still-solar pond system and to establish the ideal configuration of parameters that improves distilled water generation capacity. Experimental results showcased a maximum daily water production of 3.25 liters with an efficiency of 53.26%. The research provides valuable insights for optimizing solar still performance in real-world applications, laying the groundwork for future advancements in solar desalination technologies.