Advanced signal processing of wayside condition monitoring of railway wheelsets

Railway transport is an efficient and environmentally benign method of transport. With global warming effects intensifying it has become more urgent that mobility and economic prosperity are maintained by delivering increased transport efficient. Hence, railway transport has a significant role to play in the forthcoming decades. Punctuality and safety of railway operations is critical in ensuring unhindered transportation for passengers and freight. Rolling stock are required to operate at higher speeds and carry heavier axle loads than ever before. This puts increased pressure to rolling stock operators and infrastructure managers in trying to avoid disruption and potential accidents which also leads to higher transportation costs. Remote condition monitoring has increased in significance for railway transport over the last few years. However, there are still a lot to be done before breakthrough remote condition monitoring technologies are delivered at commercial scale in the wider international railway network. Different remote condition monitoring systems are installed wayside in order to evaluate the structural integrity of rolling stock wheelsets, detect any potential rolling stock fault in time and minimize the likelihood of a serious railway accident. The existing wayside condition monitoring system are based on infrared cameras, acoustic arrays and strain gauges. Despite significant investments by the rail industry in this area, false alarms can still occur and many of condition monitoring systems are able to detect faults once they become critical. In the present thesis, a novel approach based on integration of acoustic emission and vibration analysis together with advanced signal progressing is detailed. Tests ranging from laboratory tests under controlled conditions, all the way up to trials under actual operational conditions in the UK network have been carried out, yielding promising results. The experimental methodology employed has shown that acoustic emission is particularly efficient in detecting and ranking potential axle bearing defects. When acoustic emission is coupled with vibration analysis, it is possible to detect axle bearing defects whilst avoiding misinterpretation of wheel flats for axle bearing defects. The results obtained suggest that the widespread use of the reported methodology in the railway is feasible. The novel RCM system can enhance the reliability, availability, maintainability and safety of rolling stock wheelsets. Experimental work have been carried out under actual operational conditions in UK rail network at Cropredy, at Chiltern Railway line. The novel RCM system has been installed adjacent to Hot Box Axle Detector for comparison purposes. No interference on the track circuits is the main advantage of the proposed system. During the signal processing module of the system, freight and passenger train waveforms were identified to contain evidence of potential bearing faults. The results still require follow up validation from Network Rail. Time, frequency and time-frequency analysis have been applied to the acquired data. High amplitude peaks and signal modulation were visible at raw data. The acquired signals were transferred to frequency domain. Harmonics in frequency distribution were clearly seen. These frequency bands can be used as a reference for the band pass filter at HFRT process. HFRT algorithm has been effectively applied in the captured data in order to identify the fundamental fault frequency and its harmonics. Sidebands were also visible. TSK analysis was also applied in the raw signals. Frequency bands with high kurtosis values can be used as a reference for further analysis. In addition, laboratory experiments at University of Birmingham and Long Marston trials under controlled conditions have been carried out in order to evaluate the reliability of the system in early diagnosis of wheel and axle bearing defects. Acoustic emission and vibration signals have been collected. From the results obtained, it has effectively demonstrated that fault detection can be achieved using the frequency distribution of the signal. Defect type evaluation can be carried out by detecting the fundamental fault frequency at the HFRT process and fault quantification can achieved by Normalized Moving RMS analysis. In summary, the research contribution of this work is presented below: $\bullet$ Development and assessment of the vibroacoustic condition monitoring system for railway wheelsets. Experimental methodology and results considered in this study are the main contributions in the literature of this field. $\bullet$ In service passenger and freight trains have been monitored. Detection of potential bearing faults has been achieved. $\bullet$ Novel methodology applied at the acquired in-service data in order to determine the appropriate frequency range for the band-pass filter during the HFRT process. Frequency bands with high kurtosis values can be used as a reference for the band-pass filter. In addition, harmonics have been presented in frequency distribution of the signal. The frequency bands that harmonics were appeared can also be used for the design of the band-pass filter. $\bullet$ Comparison between advanced signal processing techniques using laboratory, in-field and in in-service signals. Detection of wheelsets faults, identification of type of the defect and quantification of fault severity can be achieved when combination of algorithm is applied at raw signals

Η μετ' αναίρεση δίκη με έμφαση στα ζητήματα μερικού δεδικασμένου

Πεδίο της βασικής προβληματικής της διπλωματικής εργασίας αποτελεί ο τρόπος με τον οποίο αποφασίζει το Δικαστήριο του Αρείου Πάγου στις περιπτώσεις που η αίτηση αναιρέσεως κριθεί παραδεκτή και βάσιμη, και κατ’ ακολουθία ποιο είναι το εύρος εξουσίας του δικαστηρίου της ουσίας στην περίπτωση που συντρέχει λόγος παραπομπής της υπόθεσης σε αυτό σε συνάρτηση με τις συνέπειες του μεταβιβαστικού αποτελέσματος. Στο δεύτερο κεφάλαιο της εργασίας παρατίθενται οι περιπτώσεις κατά τις οποίες το Ανώτατο Ακυρωτικό παραπέμπει την υπόθεση στο δικαστήριο της ουσίας που εξέδωσε την προσβαλλόμενη με αναίρεση απόφαση κατά τα άρθρα 519 ΚΠΔ και 524 ΚΠΔ, καθώς και τα όρια εξουσίας και δέσμευσης του τελευταίου από την αναιρετική απόφαση του Αρείου Πάγου, όπως επίσης ζητήματα που αφορούν στη σύνθεση του δικαστηρίου της παραπομπής και την δέσμευσή του από την κεφαλαιώδους σημασίας αρχή της απαγόρευσης χειροτέρευσης της θέσης του κατηγορουμένου.The main concern of the thesis is the way in which the Supreme Court decides in cases where the appeal is deemed admissible, and consequently what is the scope of the power of the court in the case where there is a reason to refer the case to it in relation to the consequences of the transfering effect. The second chapter of the thesis sets out the cases in which the Supreme Court refers the case back to the court of substance which issued the judgment in accordance with Articles 519 of the CCP and 524 of the CCP, as well as the limits of the latter's power and the extent to which it is bound by the appellate judgment of the Supreme Court, and also issues regarding the composition of the court of reference and its commitment to the fundamental principle of the prohibition of worsening the position of the defendant

Semi-Industrial Production of Kashkaval of Pindos Cheese Using Sheep or a Mixture of Sheep–Goat Milk and Utilization of the Whey for Manufacturing Urda Cheese

Kashkaval of Pindos cheese was successfully produced using 100% sheep milk (KS) or with the addition of 10% goat milk (KG). Urda cheese was manufactured using 100% sheep (US) or 90% sheep–10% goat (UG) whey from the production of kashkaval of Pindos cheese. Both cheeses were made taking into account their traditional cheese-making methods. The cheeses were assessed for their chemical, microbiological and organoleptic characteristics. Generally, no significant differences were observed between KS and KG cheese and between US and UG cheese regarding their physicochemical, textural characteristics, soluble nitrogen fraction and total fatty acid content. The fat content of Urda cheese was low, in accordance with the demand of consumers for healthy products. KS cheeses showed higher total volatile compounds than KG cheeses at 60 and 90 days of ripening and storage as well as lower counts of thermophilic–mesophilic lactic acid bacteria. No differences were observed in the microbial counts between US and UG cheeses. Acetone, hexanal, 2 heptanone, ethanol and toluene were found in abundance in Urda cheeses. Both kashkaval of Pindos and Urda cheeses received high scores during the organoleptic evaluation. The obtained data may lead to the production of both cheeses with standard characteristics according to the traditional recipes and improve their recognition

Fear of COVID-19 Impact on Professional Quality of Life among Mental Health Workers

Several studies have examined the impact of the COVID-19 pandemic on healthcare workers’ mental health, but only a few have investigated its detrimental effect on the mental well-being of mental health workers (MHWs). Background: The current study aimed to explore the effect of the fear of COVID-19 (FCV-19) on professional quality of life dimensions, namely compassion satisfaction (CS), burnout (BO), and secondary traumatic stress (STS) in MHWs above and beyond sociodemographic and professional factors. Methods: Hierarchical linear regression models were employed to examine the relationship of extreme FCV-19 with CS, BO, and STS in MHWs (n = 224), after considering sociodemographic variables as potential confounding factors. Extreme FCV-19 was operationalized as a binary variable with a cut-off score of ≥16.5 considered as extreme fear. Results: We found that extreme FCV-19 in MHWs is linked with increased compassion fatigue (BO and STS), and this relationship is exacerbated by younger age in regard to BO and by female gender concerning STS. CS remains unaffected by severe FCV-19, and it is higher in older participants. Conclusion: Organizational support is required to protect MHWs’ mental well-being and ensure the quality of care they provide during prolonged crises, such as the COVID-19 pandemic. Measures that intensify a sense of safety, protection, and control against COVID-19 infections in mental health services should be included in the recommendations that may reduce BO and STS among MHWs

Patient-reported needs predict perceived psychosocial disability and quality of life beyond symptom severity in schizophrenia

Purpose We examined whether patient-rated or clinician-rated needs are more strongly associated with perceived psychosocial disability (PPD) and subjective quality of life (SQOL) of schizophrenia patients, beyond symptom severity. Methods Hierarchical regression analyses were computed to test patient and clinician-rated unmet and met needs (estimated by eighty-two patient-clinician pairs) as predictors of PPD and SQOL above and beyond demographics and psychopathology. Needs, symptomatology, PPD and SQOL were estimated using Camberwell Assessment of Need (CAN), PANSS, WHODAS 2.0 and WHOQOL-BREF respectively. Results Needs were significantly associated with all WHODAS 2.0 and WHOQOL-BREF domains above and beyond demographics and PANSS variables. Clinician-rated needs were better predictors of only one WHODAS 2.0 domain, while patient-rated needs were better predictors of all other WHODAS 2.0 and WHOQOL-BREF domains. Patient-rated unmet needs were more strongly than met needs associated with the most WHODAS 2.0 and WHOQOL-BREF subscores. Conclusion This study offers the first evidence that patient-rated needs, especially unmet needs, are strongly associated, above and beyond symptomatology, with global and domain-specific PPD of schizophrenia patients. Accordingly, strong relations of patient-rated needs with SQOL emerged. Identifying and addressing patient-reported needs could facilitate PPD and SQOL improvement more effectively than interventions confined solely to symptom remission

Psychopathological Determinants of Quality of Life in People with Borderline Personality Disorder

Background: Subjective quality of life (SQOL) in people with borderline personality disorder (BPD) is a marker of disease burden; a crucial treatment outcome; an indicator of psychosocial functioning; and a measure of interventions’ effectiveness. Given the dearth of consolidated data, the current study examined psychopathological determinants of global and domain-specific SQOL in people with BPD. Methods: Hierarchical regression models were employed to examine in BPD patients (n = 150) the relationships of the number of BPD diagnostic criteria; the co-occurrence of other personality disorders (PDs); depression; state and trait anxiety; suicidality; self-harming; alcohol and substance use disorders with SQOL indices, namely physical health, psychological health, social relationships, environment, overall QOL and overall health. SQOL was estimated using the WHOQOL-BREF instrument. Results: Co-existing symptomatology such as depression, state and trait anxiety, and personality pathology, namely the co-occurrence of other PDs, exhibited significant associations with global and domain-specific SQOL, albeit depression was the strongest determinant of the most SQOL domains. In contrast, the number of BPD diagnostic criteria and central illness features such as suicidality, self-harming behaviour, and impulsivity manifested through alcohol and substance use did not exhibit significant associations with any SQOL dimension. Conclusions: Comprehensive assessment of depressive symptoms should be regularly implemented in BPD services to facilitate early detection and treatment, thereby ensuring patients’ SQOL. Accordingly, tackling anxiety and other PDs co-occurrence through appropriate interventions can facilitate more effectively SQOL improvement. Our findings can be explained by the hypothesis that co-existing psychopathology such as depression, anxiety and co-occurrence of other PDs in BPD patients represent illness severity indices rather than comorbid disorders, and might fully mediate the effect of BPD traits on SQOL. Future mediation analysis is required to elucidate this hypothesis