Machining is an indispensable manufacturing process for a wide range of engineering materials, such as metals, ceramics, and composite materials, in which the tool wear is a serious problem, which affects not only the costs and productivity but also the quality of the machined components. Thus, the modification of the cutting tool surface by application of textures on their surfaces is proposed as a very promising method for improving tool life. Surface texturing is a relatively new surface engineering technology, where microscale or nanoscale surface textures are generated on the cutting tool through a variety of techniques in order to improve tribological properties of cutting tool surfaces by reducing the coefficient of friction and increasing wear resistance.
View Article and Find Full Text PDFThe mechanism of the material destruction under discharge pulses and material removal mechanism based on the thermochemical nature of the electrical erosion during electrical discharge machining of conductive materials were researched. The experiments were conducted for two structural materials used in the aerospace industry, namely austenite anticorrosion X10CrNiTi18-10 (12kH18N10T) steel and 2024 (D16) duralumin, machined by a brass tool of 0.25 mm in diameter in a deionized water medium.
View Article and Find Full Text PDFObjective: To detect the frequency and the predictive factors of low bone mineral density in inflammatory bowel disease (IBD) patients, so as to optimize bone mineral density (BMD) monitoring and treatment for those at risk.
Subjects And Methods: Thirty Asian patients were included in this study and were divided into 18 patients with ulcerative colitis (UC), and 12 patients with Crohn's disease (CD). All patients were diagnosed by colonoscopy and histopathological biopsy and were subjected to routine laboratory investigations in addition to 25 hydroxy vitamin D levels as well as serum calcium, phosphorus and alkaline phosphatise.