75 research outputs found

    Taking Boys Seriously: a participatory action research initiative demonstrating the transformative potential of relational education

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    This article advances a gender-conscious conception of relational education emanating from the Taking Boys Seriously longitudinal participatory action research initiative in Northern Ireland. The study is grounded in the voices and experiences of boys from disadvantaged communities who have been disengaged, disinterested, or excluded from school. Specifically, we examine data from 120 educators and 442 adolescent boys involved in trialling a set of relational education principles. The findings demonstrate a groundswell of support from formal and informal educators for the advancement of relational education as a whole system approach that leads to improved holistic outcomes particularly for boys experiencing compounded educational disadvantage. Bourdieu’s concepts of cultural capital and symbolic power are utilised, framing relational education within the contested and politically infused space of education policy, pedagogy, and practice

    RELATIONSHIPS BETWEEN HITTING TECHNIQUE AND BALL CARRY DISTANCE IN CRICKET

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    The aim of this study was to identify the technique parameters characterising batsmen who generate large carry distances, ball launch speeds, and bat speeds during a range hitting task in cricket. Kinematic data were collected for 20 batsmen, and a series of ball launch, impact, and technique parameters were calculated for each trial. A regression analysis found impact location relative to the sweetspot and bat speed together to explain 70% of the observed variation in ball speed. A further regression analysis found the maximum X-factor (the separation between the pelvis and thorax segments in the transverse plane), front elbow extension, and wrist uncocking during the downswing explained 66% of the observed variation in bat speed. These findings will be useful in coaching more effective hitters, and in assessing the mechanics of generating bat speed

    Visualising scattering underwater acoustic fields using laser Doppler vibrometry

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    Analysis of acoustic wavefronts are important for a number of engineering design, communication and healthrelated reasons, and it is very desirable to be able to understand the interaction of acoustic fields and energy with obstructions. Experimental analysis of acoustic wavefronts in water has traditionally been completed with single or arrays of piezoelectric or magnetostrictive transducers or hydrophones. These have been very successful, but the presence of transducers within the acoustic region can in some circumstances be undesirable. The research reported here, describes the novel application of scanning laser Doppler vibrometry to the analysis of underwater acoustic wavefronts, impinging on circular cross section obstructions. The results demonstrate that this new non-invasive acoustics measurement technique can successfully visualise and measure reflected acoustic fields, diffraction and refraction effects

    Evolution and interaction of damage modes in fabric-reinforced composites under dynamic flexural loading

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    In this paper, an experimental study is performed to characterise the behaviour of fabric-reinforced composites used in sports products under large-deflection bending in Izod-type impact tests. X-ray micro computed tomography (micro-CT) is used to investigate various damage modes in the impacted CFRP specimens. It revealed that matrix cracking, delaminations, tow debonding, and fibre fracture were the prominent damage modes. Three-dimensional finite-element models are developed to study the onset, progression and interaction of some damage modes such as delamination and fabric fracture observed with micro-CT. A damage modelling technique based on a cohesive-zone method, which is more efficient than continuum damage mechanics approach, is proposed for analysis of interaction of damage modes. The developed numerical models are capable to simulate the damage mechanisms and their interaction observed in the tests. In this study, the pattern of damage formation observed in specimens was front-to-back, unlike bottom-to-top one in drop weight impact tests. The effect of boundary conditions on the dynamic response and damage evolution of composite laminates is also investigated. © 2013 Elsevier Ltd

    The effects of different delivery methods on the movement kinematics of elite cricket batsmen in repeated front foot drives

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    The aim of this paper was to examine differences in delivery characteristics and the resulting response exhibited by ten elite cricket batsmen when hitting repeated front foot drives against three different ball delivery methods; a bowling machine, a Sidearm™ ball thrower and a bowler. Synchronous three-dimensional Vicon motion capture technology and high-speed video were used to track batsman, bat and ball motion, and a range of discrete timing and kinematic variables were extracted from the resulting biomechanical model. Results showed significant differences in speed and ball release-to-impact time between the three delivery methods, thus questioning the validity of the bowling machine and Sidearm™ in the way they are currently used as true representations of batting against a real life bowler. Findings from the timing and kinematics of the subjects’ movements suggest a different technical response is also exhibited when facing the different delivery methods; for example batters were found to initiate movement earlier and have a lower maximum bat speed against the bowling machine, but initiate and complete their front foot stride earlier as well as moving their COM further forward in the Sidearm™ trials. © 2014 The Authors. Published by Elsevier Ltd

    Nonperturbing measurements of spatially distributed underwater acoustic fields using a scanning laser Doppler vibrometer

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    Localized changes in the density of water induced by the presence of an acoustic field cause perturbations in the localized refractive index. This relationship has given rise to a number of nonperturbing optical metrology techniques for recording measurement parameters from underwater acoustic fields. A method that has been recently developed involves the use of a Laser Doppler Vibrometer (LDV) targeted at a fixed, nonvibrating, plate through an underwater acoustic field. Measurements of the rate of change of optical pathlength along a line section enable the identification of the temporal and frequency characteristics of the acoustic wave front. This approach has been extended through the use of a scanning LDV, which facilitates the measurement of a range of spatially distributed parameters. A mathematical model is presented that relates the distribution of pressure amplitude and phase in a planar wave front with the rate of change of optical pathlength measured by the LDV along a specifically orientated laser line section. Measurements of a 1 MHz acoustic tone burst generated by a focused transducer are described and the results presented. Graphical depictions of the acoustic power and phase distribution recorded by the LDV are shown, together with images representing time history during the acoustic wave propagation

    Characterisation of mechanical behaviour and damage analysis of 2D woven composites under bending

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    In this paper, flexural loading of woven carbon fabric-reinforced polymer laminates is studied using a combination of experimental material characterisation, microscopic damage analysis and numerical simulations. Mechanical behaviour of these materials was quantified by carrying out tensile and large-deflection bending tests. A substantial difference was found between the materials' tensile and flexural properties due to a size effect and stress stiffening of thin laminates. A digital image-correlation technique capable of full-field strain-measurement was used to determine in-plane shear properties of the studied materials. Optical microscopy and micro-computed tomography were employed to investigate deformation and damage mechanisms in the specimens fractured in bending. Various damage modes such as matrix cracking, delaminations, tow debonding and fibre fracture were observed in these microstructural studies. A two-dimensional finite-element (FE) model was developed to analyse the onset and propagation of inter-ply delamination and intra-ply fabric fracture as well as their coupling in the fractured specimen. The developed FE model provided a correct prediction of the material's flexural response and successfully simulated the sequence and interaction of damage modes observed experimentally

    The effects of different delivery methods on the movement kinematics of elite cricket batsmen in repeated front foot drives

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    The aim of this paper was to examine differences in delivery characteristics and the resulting response exhibited by ten elite cricket batsmen when hitting repeated front foot drives against three different ball delivery methods; a bowling machine, a Sidearm™ ball thrower and a bowler. Synchronous three-dimensional Vicon motion capture technology and high-speed video were used to track batsman, bat and ball motion, and a range of discrete timing and kinematic variables were extracted from the resulting biomechanical model. Results showed significant differences in speed and ball release-to-impact time between the three delivery methods, thus questioning the validity of the bowling machine and Sidearm™ in the way they are currently used as true representations of batting against a real life bowler. Findings from the timing and kinematics of the subjects’ movements suggest a different technical response is also exhibited when facing the different delivery methods; for example batters were found to initiate movement earlier and have a lower maximum bat speed against the bowling machine, but initiate and complete their front foot stride earlier as well as moving their COM further forward in the Sidearm™ trials. © 2014 The Authors. Published by Elsevier Ltd

    Movement and gesture recognition using deep learning and wearable-sensor technology

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    Pattern recognition of time-series signals for movement and gesture analysis plays an important role in many fields as diverse as healthcare, astronomy, industry and entertainment. As a new technique in recent years, Deep Learning (DL) has made tremendous progress in computer vision and Natural Language Processing (NLP), but largely unexplored on its performance for movement and gesture recognition from noisy multi-channel sensor signals. To tackle this problem, this study was undertaken to classify diverse movements and gestures using four developed DL models: a 1-D Convolutional neural network (1-D CNN), a Recurrent neural network model with Long Short Term Memory (LSTM), a basic hybrid model containing one convolutional layer and one recurrent layer (C-RNN), and an advanced hybrid model containing three convolutional layers and three recurrent layers (3+3 C-RNN). The models will be applied on three different databases (DB) where the performances of models were compared. DB1 is the HCL dataset which includes 6 human daily activities of 30 subjects based on accelerometer and gyroscope signals. DB2 and DB3 are both based on the surface electromyography (sEMG) signal for 17 diverse movements. The evaluation and discussion for the improvements and limitations of the models were made according to the result
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