In situ evaluation of contact stiffness in a slip interface with different roughness conditions using ultrasound reflectometry.

Understanding the dynamic condition of the interface between a railway wheel and rail is important to reduce the risks and consider the effectiveness of countermeasures for tribological problems. Traditionally the difficulty in obtaining accurate non-destructive interfacial measurements has hindered systematic experimental investigations. Recently, an ultrasound reflectometry technique has been developed as a direct observation method of a rolling-sliding interface; however, the topography dependence under the high contact pressures in a wheel-rail contact has not been clarified. For this reason, a novel in situ measurement of the contact stiffness using ultrasound reflectometry was carried out for three different levels of roughness. A contact pressure equivalent to that in a wheel-rail interface was achieved by using a high-pressure torsion test approach. The dynamic change of contact stiffness with slip was measured using ultrasound and the influence of roughness was investigated. The measured changes were validated using a newly developed numerical simulation, and mechanisms to explain the observed behaviour were proposed in terms of fracture and plastic deformation of the asperity bonds. These findings could help in understanding the traction characteristics for different roughness conditions and also assist in understanding damage mechanisms better, such as wear and rolling contact fatigue.

Wear data for trials machining brass, titanium grade 2 and Hastelloy in order to characterize wear of micro-tools.

This data article presents data on machining trials that were carried out using 0.5 mm micro-end-mills with different coatings to characterize their wear. The data take the following forms: Tabulated wear measurements, cutting force measurements and graphs of wear against sliding distance. Three materials were machined: titanium grade 2, Hastelloy and Brass (CuZn37). Wear is measured on the flank, rake face and outside edge of the tools. Two coatings were used for each material, with wear data plotted for each material. For further information on experimental methods please refer to "Protocol for Tool Wear Measurement in Micro-milling" (Alhadeff et al., 2018).

Ectopic breast cancer: case report and literature review.

Ectopic breast tissue includes both supernumerary and aberrant breast tissue. The incidence of supernumerary tissue has been reported as high as 6% depending on the ethnic group studied. The incidence of aberrant breast tissue remains unknown. The development of malignancy within these anomalies is rare. In the following paper, the case report of a patient with an ectopic breast cancer and a second primary cancer of the left anatomic breast is described. A review of the world literature on ectopic breast cancer follows. Specific characteristics of ectopic breast cancer are defined and recommendations for management are made.