Detection and Classification System for Rail Surface Defects Based on Eddy Current.

The prospect of growth of a railway system impacts both the network size and its occupation. Due to the overloaded infrastructure, it is necessary to increase reliability by adopting fast maintenance services to reach economic and security conditions. In this context, one major problem is the excessive friction caused by the wheels. This contingency may cause ruptures with severe consequences. While eddy's current approaches are adequate to detect superficial damages in metal structures, there are still open challenges concerning automatic identification of rail defects. Herein, we propose an embedded system for online detection and location of rails defects based on eddy current. Moreover, we propose a new method to interpret eddy current signals by analyzing their wavelet transforms through a convolutional neural network. With this approach, the embedded system locates and classifies different types of anomalies, enabling an optimization of the railway maintenance plan. Field tests were performed, in which the rail anomalies were grouped in three classes: squids, weld and joints. The results showed a classification efficiency of ~98%, surpassing the most commonly used methods found in the literature.

Identification and Localization of Track Circuit False Occupancy Failures Based on Frequency Domain Reflectometry.

Railway track circuit failures can cause significant train delays and economic losses. A crucial point of the railway operation system is the corrective maintenance process. During this operation, the railway lines have the circulation of trains interrupted in the respective sector, where traffic restoration occurs only after completing the maintenance process. Depending on the cause and length of the track circuit, identifying and solving the problem may take a long time. A tool that assists in track circuit fault detection during an inspection adds agility and efficiency in its restoration and cost reduction. This paper presents a new method, based on frequency domain reflectometry, to diagnose and locate false occupancy failures of track circuits. Initially, simulations are performed considering simplified track circuit approximations to demonstrate the operation of the proposed method, where the fault position is estimated by identifying the null points and through non-linear regression on signal amplitude response. A field test is then carried out in a track circuit approximately 1500 m long to validate the proposed method. The results show that the proposed method can identify and estimate the fault location due to a short circuit between rails with high accuracy.

A revascularizaçäo precoce das artérias näo relacionadas ao infarto melhora a funçäo regional e global do ventrículo esquerdo após o infarto agudo do miocárdio / Early Noninfarct Related Arteries Revascularization Improves Regional Wall Motion Post Myocardial Infarction

PURPOSE--To evaluate if early interventions which increase flow in the non-infarct related arteries (NRA) could improve long-term ventricular function in the non-infarct (NI) area after an acute myocardial infarction (MI). METHODS--We studied regional wall motion analyzed by the center-line method in two groups of patients with significant stenoses (> or = 70 per cent ) in the NRA after successful coronary reperfusion (chemical or mechanical thrombolysis). Group I (GI) consisted of 21 patients that were submitted to early (mean 14 days) complete surgical revascularization of both NRA and infarct related artery (IRA); the 12 group II (GII) patients underwent successful revascularization of the IRA only, with percutaneous transluminal coronary angioplasty (mean 6 days). Paired ventriculograms were obtained within 48 hours of the infarction and a mean of 17 months later. RESULTS--NI area contractility in GI patients improved from -0.35 +/- 2.16 to +0.62 +/- 1.6sd/chord (p < 0.05), whereas in GII decreased from +0.54 +/- 1.78 to -0.66 +/- 1.72 sd/chord (p < 0.05), p < 0.05 between the groups at follow-up. Mean infarct area wall motion did not differ between the two groups: from -3.04 +/- 2.43 to 2.61 +/- 2.49 sd/chord in GI (p = NS), and from -2.68 +/- 2.54 to -2.93 +/- 2.35 sd/chord in GII (p = NS). Mean global left ventricular (LV) ejection fraction did not change in GII patients (0.72 +/- 0.09 and 0.67 +/- 0.12, p = NS), but significantly increased from 0.63 +/- 0.12 to 0.72 +/- 0.11 in GI patients (p < 0.01). CONCLUSION--These data suggest that early revascularization of NRA with significant stenoses can improve not only the NI area regional contractility, but also the global LV function in the long-term follow-up of post MI patients treated with thrombolytic therapy