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This paper introduces a novel approach for the detection of rotor faults in asynchronous machines, based on wavelet analysis of the stator phase current. To be more specific, the measured stator phase current is filtered through a complex wavelet. Theoretical analysis validates that the spectrum of the modulus of the result of the filtering is free from the fundamental supply frequency component, and the fault characteristics can be highlighted. This is advantageous, especially if the induction machine operates at low slip values, where the characteristic frequency components of the rotor fault are very close to the fundamental frequency component. At the same time, by matching the wavelet function to the frequencies of the faulty components, a narrow bandpass filter at the frequency region of the fault characteristic spectral components is obtained. Furthermore, in the context of this paper, features extracted using the proposed technique are used as input to a support vector machine classifier that is employed for the detection of the rotor fault. Simulation and experimental results demonstrate the effectiveness of the proposed technique. Index Terms--Asynchronous machines, fault diagnosis, feature extraction, monitoring, pattern recognition, wavelet transforms.

Transcatheter Aortic Valve Replacement (TAVR) has been established as the treatment of choice for symptomatic aortic stenosis, while it is expanding in all risk-related group categories of patients, gaining gradually ground over the surgical approach. However, complications and adverse events are yet to be effectively limited and diminished with thrombotic and hemorrhagic events being rooted as a crucial topic of discussion. Favorable anticoagulation pharmacotherapy options are constantly being revised and tested, whilst guidelines are being modified to meet current clinical evidence. This review aims to systematically assess already existing guidelines on anticoagulation in post-TAVI patients and examine novel regimens for the specific use, like apixaban, rivaroxaban, and other anticoagulants, essentially constructing a holistic point of view on future progress on this matter. The added complexity brought by coagulation-affecting comorbidities such as atrial fibrillation, coronary artery disease, and more contributes to the direct association of the topic to the quality of healthcare as a public service. The literature was systematically searched to examine the effectiveness and safety of various anticoagulation treatments and cross-evaluate them based on the according category of patients that were assigned to. Clinical trials, observational studies and systematic reviews were included and, eventually, conclusive remarks and future considerations were developed and presented. In the category of patients without prior indication to anticoagulation, SAPT was proven safer and still effective, when antiplatelet therapies were compared, while a comparison of antiplatelet versus anticoagulation strategies noted the first one, with limited data, as the optimal one. Lastly, direct oral anticoagulants were shown to be safe substitutes for vitamin K antagonists for patients with prior indication to anticoagulation [ABSTRACT FROM AUTHOR]

• Investigating the effects of CR while comparing the outcomes before and after cardiac rehabilitation in Transcatheter aortic valve implantation (TAVI) patients. • TAVI patients are considerably older with more comorbidities and disabilities. • exercise-based CR in patients with aortic stenosis treated with TAVI improves exercise tolerance and functional independence. • rehabilitation is safe even in advanced age and caused no complications related to the program. • need of an improved progra including long-term benefits and follow-ups. Despite the increasing popularity of Transcatheter aortic valve implantation (TAVI) in patients with high surgical risk, there is no current guideline for the management of patients following the intervention. This systematic review and meta-analysis aims to summarize and analyse all clinical data and evidence regarding the effectiveness and outcomes of CR following TAVI. The first meta-analysis measured the walked distance in the Six-Minute Walk Test (6MWT) and the second meta-analysis included studies that showed the Barthel Index (BI) before and after CR. The mean distance walked prior to CR was 235.88 ± 69.36 m increased to 292.12 ± 54.92 m after rehabilitation, signifying a moderate clinically relevant effect size (0.593 (0.42, 0.76); P =0.00). The mean BI score before CR was 76.6 ± 11.5 which increased to 89.8 ± 5.5 after the programme and similarly demonstrated a significant standardized mean improvement (0.75 (0.57, 0.93); I= 0.00). Exercise-based CR in patients with aortic stenosis treated with TAVI demonstrated a significant improvement in exercise tolerance and functional independence shown by the 6MWT and BI. [ABSTRACT FROM AUTHOR]

This paper examines the torsional behaviour of the subsynchronous cascade drive. A four-mass model of the mechanical subsystem is considered in order to study the torsional oscillations of the shaft train due to the - characteristic for this drive - pulsation of the electromagnetic torque. A theoretical analysis is carried out and some guidelines are proposed regarding the design of the mechanical subsystem in order to avoid excessive torsional oscillations which may lead to severe mechanical damage in the shaft train. Finally, the torsional dynamics of this system are also investigated via simulation, where the non-linear characteristic of the mechanical coupling is additionally taken into account. [ABSTRACT FROM AUTHOR]

In this research, an investigation of the fault modes of the rectifier of the subsynchronous cascade drive is carried out. It is shown that faults in the power electronic converter cause electromagnetic torque pulsations with amplitudes much higher than usual and with frequencies near the natural frequencies of the mechanical subsystem. This type of fault must be immediately detected in order to avoid damages in the mechanical subsystem, something which has also been proven by experience in service. Towards this goal, a novel approach for real-time fault detection and accurate diagnosis is investigated, based on the monitoring of the rotor current space vector angle, in order to extract features which indicate the specific fault modes of operation. The merits of this approach are demonstrated through simulation and experimental results. [ABSTRACT FROM AUTHOR]