Contact dermatitis is an inflammatory skin disease due to contact with different substances and caused by two mechanisms: Allergy and irritation. Contact dermatitis is a common skin disease and the most common occupational dermatosis. Differentiating between allergic and irritant contact dermatitis is essential in the identification of etiologic factor(s) and hence, its control and prognosis. T...

The generation of wheel–rail-sliding frictional heat is often accompanied by transverse displacement a wheel. To study the thermal problem wheel–rail sliding friction at two-point contact, this paper uses an LM tread wheel and 60 kg·m−1 rail as examples. A thermal–mechanical-coupled finite-element model equal proportion established. direct-coupling method used to analyze thermal–mechanical coup...

Wheel/rail contact simulation is one of the most complicated problems in the modeling of railway vehicles. The wheel/rail interaction plays a unique role in rail vehicle dynamics. In this paper, the dynamic response of the wheel on irregular rail track is analyzed with analytical approach using the method of Multiple Scales (MMS). The Hertzian contact theory is used to obtain the relationshi...

in the last decade, decrease of the wear rate, increase in the axel load, and the velocity of the trains have changed the main damage mechanism of railway wheels from wear to rolling contact fatigue (rcf). rcf may lead to surface and subsurface cracks. the interaction between wear and rcf, removes the surface cracks, but the subsurface crack propagate gradually, and may lead to deeper and more ...

We investigated in detail the dermoscopic and histopathological findings in a case of a superficial type of multiple basal cell carcinomas (BCCs). These multiple lesions (occurring in the chest, neck, and back) showed three different findings, respectively. Dermoscopy of the erythematous and brown-colored patch on the anterior chest showed spoke wheel areas, and the histopathological cross-sect...

background: occupational contact dermatitis, especially in hand, is one of the most common occupational disorders. the present study aimed at evaluating patients with occupational allergic contact dermatitis (acd) caused by common allergens based on occupation type and disease history.   methods: this cross-sectional study aimed at evaluating the data of the patients with probable diagnosis of ...

The tangential contact forces that arise at the interface between the wheel of a railway vehicle and the rail provide all the traction, braking, and guidance required by the vehicle. These forces are the result of microslip or creepage and can become unstable exciting vibration of the wheel, particularly at frequencies corresponding to the wheel’s axial (and radial) modes. Although theories exi...

Wear in rolling contact is a complex phenomenon because it multi-scale and multi-physical by nature involves many strongly correlated parameters. It makes the numerical calculation of wear very challenging. In order to simulate wear, better understanding influencing parameters involved importance. This work presents new railway wheel based on Archard's equation combined with spatial statistic a...

In this work the influence of considering wheel-rail contact creepages on fatigue crack growth rates due to Rolling Contact Fatigue (RCF) is studied. For purpose, FASTSIM algorithm, which considers moving complex pressure distribution with slipping and adhesion zones patch, has been implemented in Abaqus using FORTRAN code subroutines. The developed methodology validated a 60E1 rail profile mod...

in this paper effects of fractured sleepers on rail track vibration under moving wheelset have been investigated. two parallel rails of the track have been modeled as euler-bernoulli beams on elastic points as rail pads. also sleepers have been modeled as visco-elastic euler-bernoulli beams. it is assumed that, some sleepers under the rail track have been fractured and modeled by two beams. the...