Nowadays, the technical practice uses polymers or polymer composites largely in many engineering applications due to their unique advantage of excellent mass-to-strength ratio. The objective of this article is to determine the tribological aspects of single-edge machining (turning) for extruded polyamide 6 (PA 6 E) base polymer and two types of composites namely, PA 66 GF30 and PA 6G-H ELS with varying parameters. The tribological test was conducted and analysed using a mathematical statistical method to describe the relationship between the parameters and friction force. The contact area of the tool was found to be linearly increased with the increasing feed rate. The main cutting force does not depend on the cutting speed which can happened due to the absence of local heat generation at the tool tip. In tribological testing, a transition of steady-state to unstable state friction was observed with a sound effect for different materials which mainly depends on the material combination and pv level used. For pure PA 6 E, increasing pv level resulted in a longer and lower friction steady-state phase. Whereas, a different trend can be observed for composites with the help of developed model which has good agreement with the experimental results.
Polyvinylidene fluoride (PVDF) piezoelectric sensors are widely recognized for their flexibility, high sensing accuracy, and self-powered operation. This study addresses the challenge of improving the precision of output electrical measurements in piezoelectric flexible sensors under external force. A linear relationship between the piezoelectric sheet’s response and the applied force is derived and simulated using the first piezoelectric equation. An experimental setup is then constructed to measure output voltage under varying forces, with results analyzed using least squares fitting to establish the force-voltage relationship. A comparison of theoretical and experimental results demonstrates strong alignment, validating the method’s simplicity, feasibility, and effectiveness. Both simulation and experimental findings confirm that the sensor’s output voltage increases linearly with applied force within a defined range, offering insights for enhancing sensor performance.
The effects of homogenization on the deformation behavior, microstructure evolution, and mechanical properties of the continuously cast Al–Mg–Si–Cu alloy during the Conform continuous extrusion forming process were subject to a meticulous investigation. The findings indicated that the continuously cast Al–Mg–Si–Cu alloy possesses a refined dendritic structure, with the secondary phase partially dissolved posthomogenization, yet giving rise to a multitude of dispersed precipitated phase particles. The second phase on the dense dendrite boundary enriches the substructure of deformed structure by promoting dynamic recrystallization nucleation. However, for the homogenized alloy, the dispersed particles have relatively weak refining effect on the hot deformation structure. Conform process breaks the larger second phase and the dispersed phase particles precipitated in the subsequent homogenization process. These dispersed phase particles, by pinning dislocations and grain boundaries, impede the growth of recrystallized grains at comparatively lower temperatures, thereby enabling the homogenized alloy to achieve a finer grain size. Additionally, the tensile strength of the T5 homogenized alloy has been augmented by 18.83%, attributable to the elevated concentration of solute atoms in the solid solution.
Heparin (HEP) is a form of glycosaminoglycan, that can influence physiological functions. Therefore, heparin hydrogels offer broad application prospects in tissue engineering. Here, the HEP-based injectable hydrogel was prepared using HEP and sodium-alginate (SA). To create HEP with amino groups, adipic dihydrazide was grafted to HEP using the Adipic Dihydrazide (ADH) method. Then, SA was oxidised by sodium periodate. A novel HEP-based hydrogel was formed through the Schiff base reaction. Scanning electron microscopy (SEM) showed that the pores in the hydrogel were suitable for cell growth. The cytocompatibility of the HEPbased hydrogel was investigated by MTT colorimetric assay and cell live/dead staining. The results showed that the HEP-based hydrogel has good biocompatibility, and can promote cell growth and proliferation. In conclusion, the HEP-based hydrogel can be applied in regenerative tissue engineering.
This study evaluated the effect of Punica granatum peel extracts on candida adhesion to conventional and computer-aided design and computer-aided manufacturing (CAD/CAM) denture acrylic materials. Thirty acrylic resin discs with a diameter of 10 mm and a thickness of 3 mm were prepared using conventional methods, CAD/CAM milling, and 3D printing (n = 10). To mimic clinical settings, thermocycling and mechanical brushing were applied. Surface roughness was measured before and after soaking in the Punica granatum extract. The discs were submerged in the extract to test for candida adherence, and the growth of the candida was measured as colony-forming units (CFU/mL). Paired sample t-tests, one-way ANOVA, and Tukey’s post hoc tests (α = 0.05) were used for statistical analysis. All the tested materials demonstrated a significant increase in surface roughness after soaking in the extract (p < 0.05). Candida adhesion varied between the conventional and digitally processed materials; conventional acrylic resins showed the highest mean CFU/mL, followed by 3D-printed and milled acrylic resins. This study underscores the potential of Punica granatum peel extract as a valuable addition to dental care, particularly in reducing candida adhesion on CAD/CAM denture surfaces.
