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Generalized Statistical Indicators-Guided Signal Blind Deconvolution for Fault Diagnosis of Railway Vehicle Axle-Box Bearings
Get PDFVibration impulses caused by surface defects of railway vehicle axle-box bearings are important features for fault diagnosis. To accurately diagnose axle-box bearing surface defects, robust blind deconvolution (BD) methods are proposed to extract defect-induced repetitive impulses from axle-box vibration measurements in this article. Specifically, a unified theoretical framework for the BD methods using time-domain and frequency-domain generalized statistical indicators as objective functions is established respectively by converting the deconvolution problem into a generalized Rayleigh quotient-based generalized eigenvalue problem. On this basis, two new BD methods for extracting repetitive impulse features are presented by employing the robust power function-based Gini index as the objective function. They obtain optimal deconvolution filters by adaptively evaluating repetitive transient features in the squared envelope and squared envelope spectrum of the filtered signal, respectively. The developed methods are verified on bench experimental signals of manufactured and naturally occurring axle-box bearing faults. The results show that the presented BD methods can effectively enhance repetitive impulse features and diagnose various defects of railway vehicle axle-box bearings
Dynamic responses of locomotive axle box bearings under varying operating conditions
Get PDFAxle box bearings (ABBs) are a vital component of a railway locomotive, ensuring their reliable performance requires an in-depth understanding of their dynamic behaviour. This work theoretically derives a locomotive–track longitudinal–vertical coupled dynamics model that takes detailed dynamics of the ABBs into account. The model considers a number of complex interactions, such as non-linear contact and friction forces within the ABB, wheel–rail interactions, and track irregularities. The motions of ABB are coupled with the wheelset and bogie frame, allowing detailed investigation of the ABB dynamic behaviour during operation. The correctness of the proposed model is verified in both the time and frequency domains by comparing with field test. The dynamic characteristics of ABBs under varying operating conditions were comprehensively investigated. The results demonstrate that track irregularities have a non-negligible influence on the dynamic forces of the locomotive ABB. Furthermore, the axle load transfer occurs during loading conditions, which leads to significant differences in vertical and longitudinal dynamic interactions within the ABBs across wheelsets. It is clear that the operating conditions of the locomotive should be suitably considered in the dynamic assessment, operation, and maintenance of ABBs.</p
Context matters? The influence of happiness, trust, democracy and economic development on DEI policies in communications in Latin America and the Caribbean
Get PDFPurposeAlthough significant research has been developed in the Global North regarding diversity, equity and inclusion (DEI) in the communication field, the subject has been neglected in the Latin American and Caribbean region. The purpose of this paper is twofold: on the one hand, this article analyzes to what extent DEI policies are implemented in LAC organizations, and on the other, it examines how four contextual variables (trust, democracy, economic development and happiness) impact the development of DEI in the region.Design/methodology/approachA dataset corresponding to the 2022/2023 edition of the Latin American Communication Monitor is used. For the study of DEI policies and their relationship with communication management in the region, four dimensions of study are defined, as well as two indices related to DEI.FindingsThe most relevant category linked to DEI for LAC professionals is generation and age, above other usually more consolidated categories such as gender or sexual orientation. As for contextual variables, only democracy seems to really influence the incorporation of DEI policies in communications, given that generalized trust would not affect their implementation, while happiness and economic development do not show conclusive evidence.Originality/valueThis study can contribute to expanding the knowledge on the corporate communication field by conducting contextualized and more inclusive research and, therefore, decolonizing proposals from the Global North
The quest for efficiency in higher education in England:lessons learned for developed economies
No full textOver recent decades, universities in England have transitioned from providing higher education (HE) for the elite to HE for the masses. Funding mechanisms have changed, cost-sharing has shifted from public to private sources, and efficiency and productivity have been emphasized. Three excellence frameworks relating to research, teaching, and knowledge exchange have been introduced to assess performance. In this paper, we explore the systems of performance measurement and funding implemented in English HE and critically appraise these against the recommendations from the relevant literature. We conclude that these frameworks, by separately assessing performance in the three missions, inadequately account for synergies between activities, thereby ignoring the civic nature of universities and possibilities for economies of scale and scope. We conclude by highlighting some emerging areas for future research. While the focus of the paper is English HE, the themes and findings are relevant to all HE sectors around the world.</p
Threshold modeling for antibiotic stewardship in Oman
No full textBackground: Antimicrobial stewardship supports rational antibiotic use. However, balancing access to antibiotic treatment while controlling resistance is challenging. This research used a threshold logistic modeling approach to identify targets for antibiotic usage associated with carbapenem-resistant Acinetobacter baumannii, carbapenem-resistant Klebsiella pneumonia, and extended-spectrum β-lactamases-producing Escherichia coli incidence in hospitals. Methods: This study utilizes an ecological population-level design. Monthly pathogen cases and antibiotic use were retrospectively determined for inpatients between January 2015 and December 2023. The hospital pharmacy and microbiology information systems were used to obtain this data. Thresholds were identified by applying nonlinear modeling and logistic regression. Results: Incidence rates of 0.199, 0.175, and 0.146 cases/100 occupied bed-days (OBD) for carbapenem-resistant A baumannii, carbapenem-resistant K pneumonia, and extended-spectrum β-lactamases-producing E coli, respectively, were determined as the cutoff values for high (critical) incidence rates. Thresholds for aminoglycosides (0.59 defined daily dose [DDD]/100 OBD), carbapenems (6.31 DDD/100 OBD), piperacillin-tazobactam (3.71 DDD/100 OBD), third-generation cephalosporins (3.71 DDD/100 OBD), and fluoroquinolones (1.91 DDD/100 OBD), were identified. Exceeding these thresholds would accelerate the gram-negative pathogens' incidence rate above the critical incidence levels. Conclusions: Threshold logistic models can help inform and implement effective antimicrobial stewardship interventions to manage resistance within hospital settings.</p
Condition monitoring of journal bearings based on acoustic emissions:A state-of-the-art review
No full textThis paper provides a thorough review of the advancements in acoustic emission (AE) technology used for monitoring journal bearings. Firstly, the AE sources generated from journal bearings under different lubrication regimes are classified and discussed. Subsequently, a comparative analysis of parametric analysis methods, waveform methods, and artificial intelligence recognition methods for the bearing AE signal analysis is conducted, highlighting their respective principles, pros and cons, and applications. Additionally, an overview of physical models representing AE waves on relatively sliding surfaces is provided from the wave generation mechanism perspective, and each model's applicable conditions are compared. Finally, an in-depth discussion is presented, and future research directions are highlighted
Criminalising Boycott Calls:How Hate Speech Laws Are Weaponised in Turkey
No full textCan a call for boycott ever amount to hate speech? In an era of deepening political divides, the question is increasingly influenced by geopolitics rather than human rights law. The Turkish Government's criminalisation of boycott calls in response to protests against political repression highlights the dangers of weaponising hate speech laws, echoing a global double standard that undermines the universal application of human rights protections
Ernest Berk:A Musical Outsider – A Live Diffusion Concert
No full textErnest Berk: A Musical Outsider is a multichannel concert showcasing the work of pioneering electronic music composer Ernest Berk. As part of the AHRC-funded project “Ernest Berk: An Expressionist Outsider” the project team have meticulously restored Berk’s lost recordings made between 1957 and 1983. The performance crafts a unique experience of England’s unsung electronic music history
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