ABSTRACT
Rolling contact wear/fatigue tests on wheel/rail specimens are important to produce wheels and rails of new materials for improved lifetime and performance, which are able to operate in harsh environments and at high rolling speeds. This paper presents a novel non-invasive, all-optical system, based on a high-speed video camera and multiple laser illumination sources, which is able to continuously monitor the dynamics of the specimens used to test wheel and rail materials, in a laboratory test bench. 3D macro-topography and angular position of the specimen are simultaneously performed, together with the acquisition of surface micro-topography, at speeds up to 500 rpm, making use of a fast camera and image processing algorithms. Synthetic indexes for surface micro-topography classification are defined, the 3D macro-topography is measured with a standard uncertainty down to 0.019 mm, and the angular position is measured on a purposely developed analog encoder with a standard uncertainty of 2.9°. The very small camera exposure time enables to obtain blur-free images with excellent definition. The system will be described with the aid of end-cycle specimens, as well as of in-test specimens.
ABSTRACT
The authors report a case of Horton's arteritis and associated rheumatic polymyalgia, which was complicated from a diagnostic point of view by the atypical clinical and biohumoral conditions. Both the subjective and objective symptoms were relatively unclear compared to laboratory and instrumental findings which pointed strongly to an autoimmune disorder. The coexistence of biohumoral data of a cholestatic hepatitic type, not common to other pathologies, although reported in the literature, led to further diagnostic difficulties. Diagnosis was finally confirmed by temporal artery biopsy.
