Novel spectral kurtosis technology for adaptive vibration condition monitoring of multi-stage gearboxes

In this paper, the novel wavelet spectral kurtosis (WSK) technique is applied for the early diagnosis of gear tooth faults. Two variants of the wavelet spectral kurtosis technique, called variable resolution WSK and constant resolution WSK, are considered for the diagnosis of pitting gear faults. The gear residual signal, obtained by filtering the gear mesh frequencies, is used as the input to the SK algorithm. The advantages of using the wavelet-based SK techniques when compared to classical Fourier transform (FT)-based SK is confirmed by estimating the toothwise Fisher's criterion of diagnostic features. The final diagnosis decision is made by a three-stage decision-making technique based on the weighted majority rule. The probability of the correct diagnosis is estimated for each SK technique for comparison. An experimental study is presented in detail to test the performance of the wavelet spectral kurtosis techniques and the decision-making technique

"Knowing That I'm Not Necessarily Alone in My Struggles": UK Autistic Performing Arts Professionals' Experiences of a Mentoring Programme

This research examined whether professional mentoring could have a positive effect on the occupational self-efficacy of autistic performing arts professionals. We compared the outcomes of one group who received mentoring to a waitlist control group. 26 participants took part in this study: 15 autistic mentees and 11 mentors, three of whom were also autistic. The mentoring programme was well received and felt to be beneficial by the participating mentees and mentors, particularly regarding gains in mentees’ occupational self-efficacy. Professional mentoring also addressed several work-oriented challenges identified by autistic performing arts professionals such as feelings of isolation in the industry and need for consultation and advice on both a professional level, and for mentees with autistic mentors, also a neurodivergent one

Asymmetric vibrations and chaos in spherical caps under uniform time-varying pressure fields

This paper presents a study on nonlinear asymmetric vibrations in shallow spherical caps under pressure loading. The Novozhilov’s nonlinear shell theory is used for modeling the structural strains. A reduced-order model is developed through the Rayleigh–Ritz method and Lagrange equations. The equations of motion are numerically integrated using an implicit solver. The bifurcation scenario is addressed by varying the external excitation frequency. The occurrence of asymmetric vibrations related to quasiperiodic and chaotic motion is shown through the analysis of time histories, spectra, Poincaré maps, and phase planes

Comparing the Executive Function Ability of Autistic and Non-autistic Adolescents with a Manualised Battery of Neuropsychological Tasks

Performance on a single executive function (EF) task (e.g., a card sorting task) is often taken to represent ability on the underlying subcomponent of EF (e.g., set shifting) without accounting for the non-specific and non-executive skills employed to complete the task. This study used a manualised battery of EF tasks to derive individual task scores and latent EF scores. Seventy-nine adolescents aged between 11 and 19 years, including 37 autistic and 42 non-autistic participants, matched on cognitive ability, completed the battery. Autistic adolescents had moderate global EF difficulties and had significantly more difficulties on some individual tasks. However, the samples did not differ on any of the specific individual subcomponents of EF (fluency, cognitive control and working memory)

‘This is what we’ve always wanted’: Perspectives on young autistic people’s transition from special school to mainstream satellite classes

Background & aims According to parents, teachers and policymakers alike, including autistic children and young people in mainstream schools is notoriously difficult – especially so for the significant minority of young people on the autism spectrum with additional intellectual, communication and behavioural needs. The current study sought to understand the perceived impact of one particular, emerging model of education, in which selected students from special schools are transferred to dedicated ‘satellite’ classes in local, mainstream partner schools, while continuing to receive the tailored curriculum and specialist teaching of the originating school. Methods We conducted interviews with London-based young autistic people (n = 19), their parents/carers and teachers to understand their experiences of transitioning from specialist to satellite mainstream provision. Results Participants overwhelmingly welcomed the prospect of transition and its perceived benefits in the short and longer term. Young people and families celebrated achieving access to ‘more normal places and things’, ‘seeing what others are doing’, and greater autonomy, without losing the trusted expert support of their former special school. Young people also felt a deep sense of belonging to their new mainstream school, despite only being minimally included in regular mainstream classes and activities. Teachers were equally positive and felt that their students had responded to higher expectations in their new mainstream schools, reportedly resulting in better behavioural regulation and more sustained attention in the classroom. Conclusions The strikingly positive evaluations provided by all participants suggest that this satellite model of education might have advantages for young autistic people with additional intellectual disability, when appropriate support extends across transition and beyond. Implications These findings shed light on the experiences of an under-researched group of autistic students and a specific model of education – following a needs-based perspective on inclusion – that seeks to extend their participation in local schools. Future research should examine the potential effects of satellite classrooms on the knowledge of, and attitudes toward, autism in non-autistic mainstream peers

Natural Frequencies of Triple-Walled Carbon Nanotubes

none3noIn this paper, the linear vibrations of Triple-Walled Carbon Nanotubes (TWNTs) are analysed. A multiple elastic shell model is considered. The shell dynamics is studied in the framework of the Sanders-Koiter shell theory. The van der Waals (vdW) interaction between two layers of the TWNT is modelled by a radius-dependent function. The circular cylindrical shell deformation is described in terms of longitudinal, circumferential and radial displacements. Simply supported, clamped and free boundary conditions are considered. The three displacement fields are expanded by means of a double mixed series based on Chebyshev orthogonal polynomials for the longitudinal variable and harmonic functions for the circumferential variable. The Rayleigh-Ritz method is applied to obtain approximate natural frequencies and mode shapes. The present model is validated in linear field by means of data derived from the literature. This study is focused on determining the effect of the geometry and boundary conditions on the natural frequencies of TWNTs.openAndrisano, Angelo O.; Pellicano, Francesco; Strozzi, MatteoAndrisano, Angelo O.; Pellicano, Francesco; Strozzi, Matte

Employability skills: Profiling data scientists in the digital labour market

In the current scenario, data scientists are expected to make sense of vast stores of big data, which are becoming increasingly complex and heterogeneous in nature. In the context of today's rapid technological development and its application in a growing array of fields, this role is evolving simultaneously. The present study provides an insight into the current expectations of employers seeking to hire individuals with this job title. It is argued that gaining a better understanding of data scientists’ employability criteria and the evolution of this professional role is crucial. The focus is placed on the desired prerequisites articulated through job advertisements, thus deriving relevant means for furthering theory and practice. It was achieved by harvesting relevant data from job advertisements published on US employment websites, which currently attract the US market's highest recruitment traffic. The key contribution of this study is to have identified means of systematically mapping skills, experience, and qualifications sought by employers for their data scientists, thus providing a data-driven pathway for employability and avoiding skills gaps and mismatches in a profession that is pivotal in the Industry 4.0

Resonances and nonlinear vibrations of circular cylindrical shells, effects of thermal gradients

In this paper, the results of an experimental campaign focused on the vibrations of shells are presented. More specifically, the goal is to investigate the effect of thermal gradients across the shell thickness on the nonlinear dynamics. The shell is made of polymeric material and an aluminum mass is clamped on one end of the shell; the other shell end is clamped to an electrodynamic shaker, which provides a base harmonic excitation. Tests are performed in a controlled environment where a thermal gradient on the shell thickness is generated by means of a climatic chamber and an internal cartridge heater. Different temperature gradients and base excitation levels have been considered. The nonlinear dynamic scenario is analyzed through amplitude–frequency diagrams, bifurcation diagrams, waterfall diagrams, time histories, Fourier spectra, phase portraits, and Poincaré maps. Results show a strong effect of the temperature on the dynamic response of the shell: subharmonic, quasi-periodic, and chaotic vibrations take place as well as large amplitude vibrations, high sound levels are detected

Dissociation in How Core Autism Features Relate to Interoceptive Dimensions: Evidence from Cardiac Awareness in Children

Interoception in autism is receiving increasing research attention. Previously, differences were identified in autism on both objective and subjective measures of interoception, and an association with anxiety. Yet, it is currently unknown how interoception relates to core autism features. Here, in 49 autistic children, we consider how interoceptive accuracy (measured with heartbeat detection tasks) and sensibility (subjective judgements of awareness) relate to overall severity on the Autism Diagnostic Observation Schedule, and symptom domains of social-affective and repetitive, restricted behaviors. Socio-affective features were related to interoceptive sensibility, while repetitive restricted behaviors were related to interoceptive accuracy. This dissociation suggests disparate interoceptive mechanisms for the formation and/or maintenance of autistic features