20000 research outputs found
Sort by
High-bandwidth multimode self-sensing in bimodal atomic force microscopy
No full textUsing standard microelectromechanical system (MEMS) processes to coat a microcantilever with a piezoelectric layer results in a versatile transducer with inherent self-sensing capabilities. For applications in multifrequency atomic force microscopy (MF-AFM), we illustrate that a single piezoelectric layer can be simultaneously used for multimode excitation and detection of the cantilever deflection. This is achieved by a charge sensor with a bandwidth of 10 MHz and dual feedthrough cancellation to recover the resonant modes that are heavily buried in feedthrough originating from the piezoelectric capacitance. The setup enables the omission of the commonly used piezoelectric stack actuator and optical beam deflection sensor, alleviating limitations due to distorted frequency responses and instrumentation cost, respectively. The proposed method benefits from a more than two orders of magnitude increase in deflection to strain sensitivity on the fifth eigenmode leading to a remarkable signal-to-noise ratio. Experimental results using bimodal AFM imaging on a two component polymer sample validate that the self-sensing scheme can therefore be used to provide both the feedback signal, for topography imaging on the fundamental mode, and phase imaging on the higher eigenmode
User satisfaction with the structure and content of the NEXit intervention, a text messaging-based smoking cessation programme
No full textBackground: Smoking is still the leading cause of preventable ill health and death. There is a limited amount of evidence for effective smoking cessation interventions among young people. To address this, a text messaging-based smoking cessation programme, the NEXit intervention, was developed. Short-term effectiveness, measured immediately after the 12-week intervention revealed that 26% of smokers in the intervention group had prolonged abstinence compared with 15% in the control group. The present study was performed to explore the users’ experiences of the structure and content of the intervention in order to further develop the intervention.
Methods: Students participating in the main NEXit randomized controlled trial were invited to grade their experiences of the structure and content of the intervention after having completed follow-up. The participants received an e-mail with an electronic link to a short questionnaire. Descriptive analysis of the distribution of the responses to the questionnaire was performed. Free-text comments to 14 questions were analysed. Results: The response rate for the user feedback questionnaire was 35% (n = 289/827) and 428 free-text comments were collected. The first motivational phase of the intervention was appreciated by 55% (158/289) of the participants. Most participants wanted to quit smoking immediately and only 124/289 (43%) agreed to have to decide a quit-date in the future. Most participants 199/289 (69%) found the content of the messages in the core programme to be very good or good, and the variability between content types was appreciated by 78% (224/289). Only 34% (97/289) of the participants thought that all or nearly all messages were valuable, and some mentioned that it was not really the content that mattered, but that the messages served as a reminder about the decision to quit smoking. Conclusions: The programme was largely perceived satisfactory in most aspects concerning structure and content by young people and most participants stated that they would recommend it to a friend who wants to quit smoking. The motivational phase might be worth shortening and the number of messages around the quit date itself reduced. Shorter messages seemed to be more acceptable
Teaching and learning preferences of ‘Generation Y’ occupational therapy students in practice education
No full textBackground/Aims: Practice education is integral to health professional curricula. There is emerging evidence that student generational attributes may be impacting on practice education. Students born between 1982 and 2000, termed ‘Generation Y’, are said to have a different outlook on learning to those students from other generational groups. However, there is little research from student perspectives to investigate these claims. This study aimed to identify ‘Generation Y’ occupational therapy students' preferred teaching and learning approaches in practice education. Methods: Using a qualitative descriptive approach and purposive sampling, 22 semi-structured interviews were undertaken with third and fourth year ‘Generation Y’ occupational therapy students from one Australian university. Interview transcripts were analysed thematically. Findings: Four themes emerged from the data: developing practice skills and confidence; essential communication; valued educational approaches; and the supervisory relationship and the team. Conclusion:
Findings relate to ‘Generation Y’ characteristics. Practice educators may need to consider that these students have unique learning preferences. Students prefer ‘doing’ to observing, they want to be given clear expectations and responsibility for their own work tasks, they want to work in a team, they prefer to self-evaluate prior to feedback and access to the internet is essential for their learning
Finite difference simulation of MHD radiative flow of a nanofluid past a stretching sheet with stability analysis
No full textIn the present study, unsteady heat and mass nanofluid flow past a stretching sheet with the effect of thermal radiation and magnetic field was carried out. To obtain non-similar equation, the boundary layer governing equations including continuity, momentum, energy and concentration balance were non-dimensionaised by usual transformation. The non-similar approach was employed, which depends on the dimensionless parameters such as Magnetic parameter (M), Radiation parameter (R), Prandtl number (Pr), Eckert number (Ec) Lewis number (Le), Brownian motion parameter (Nb), Thermophoresis parameter (Nt), Local Reynolds number (Re) and velocity parameter (b/a). The temperature and concentration distributions are found affected by these dimensionless parameters. The obtained equations have been solved by explicit finite difference method (EFDM). A theoretical model of the stability and convergence to describe the aspects of the finite difference scheme was developed in this study. This analysis makes the EFDM approach more accurate and able to provide the convergence criteria of the method (Pr ≥ 0.375 and Le ≥ 0.25). The temperature and concentration profiles are discussed for the different values of the dimensionless parameters by considering different time steps. The present computational investigation finds applications in the area of magnetic nanomaterials processing
Developing independent listening skills for English as an additional language students
No full textThis paper describes an action research project to develop online, self-access listening resources mirroring the authentic academic contexts experienced by graduate university students. Current
listening materials for English as an Additional Language (EAL) students mainly use Standard American English or Standard British pronunciation, and far fewer materials use Australian or regional accents. Materials are also simplified or spoken at a slower speed, emphasizing comprehension-type questions, despite the fact that literature reveals effective listening development involves practice in real-life listening contexts. Academic listening materials conversely emphasize the formal lecture and development of note-taking skills. We developed a range of activities where listening input was accompanied by materials reflecting top-down and bottom-up strategies as well as other cognitive and meta-cognitive skills. Materials were developed over two action research cycles involving EAL research student participants. Paper-based exercises were trialed and then
developed into online materials where students could create their own listening materials and build portfolios. Results from the participants in the workshops/focus groups indicate they were able to
develop their listening skills independently because of the explicit and focused approach of the materials. However, even more explicit and simple instructional design was needed when translated into the online environment
A picture tells a thousand words: a content analysis of concussion-related images online
No full textBackground and aim: Recently image-sharing social media platforms have become a popular medium for sharing health-related images and associated information. However within the field of sports medicine, and more specifically sports related concussion, the content of images and meta-data shared through these popular platforms have not been investigated. The aim of this study was to analyse the content of concussion-related images and its accompanying meta-data on image-sharing social media platforms. Methods: We retrieved 300 images from Pinterest, Instagram and Flickr by using a standardised search strategy. All images were screened and duplicate images were removed. We excluded images if they were: non-static images; illustrations; animations; or screenshots. The content and characteristics of each image was evaluated using a customised coding scheme to determine major content themes, and images were referenced to the current international concussion management guidelines. Results: From 300 potentially relevant images, 176 images were included for analysis; 70 from Pinterest, 63 from Flickr, and 43 from Instagram. Most images were of another person or a scene (64%), with the primary content depicting injured individuals (39%). The primary purposes of the images were to share a concussion-related incident (33%) and to dispense education (19%). For those images where it could be evaluated, the majority (91%) were found to reflect the Sports Concussion Assessment Tool 3 (SCAT3) guidelines. Conclusions: The ability to rapidly disseminate rich information though photos, images, and infographics to a wide-reaching audience suggests that image-sharing social media platforms could be used as an effective communication tool for sports concussion. Public health strategies could direct educative content to targeted populations via the use of image-sharing platforms. Further research is required to understand how image-sharing platforms can be used to effectively relay evidence-based information to patients and sports medicine clinicians
"There's a housing crisis going on in Sydney for Aboriginal people": focus group accounts of housing and perceived associations with health
No full textBackground: Poor housing is widely cited as an important determinant of the poor health status of Aboriginal Australians, as for indigenous peoples in other wealthy nations with histories of colonisation such as Canada, the United States of America and New Zealand. While the majority of Aboriginal Australians live in urban areas, most research into housing and its relationship with health has been conducted with those living in remote communities. This study explores the views of Aboriginal people living in Western Sydney about their housing circumstances and what relationships, if any, they perceive between housing and health. Methods: Four focus groups were conducted with clients and staff of an Aboriginal community-controlled health service in Western Sydney (n = 38). Inductive, thematic analysis was conducted using framework data management methods in NVivo10. Results: Five high-level themes were derived: the battle to access housing; secondary homelessness; overcrowding; poor dwelling conditions; and housing as a key determinant of health. Participants associated their challenging housing experiences with poor physical health and poor social and emotional wellbeing. Housing issues were said to affect people differently across the life course; participants expressed particular concern that poor housing was harming the health and developmental trajectories of many urban Aboriginal children. Conclusions: Housing was perceived as a pivotal determinant of health and wellbeing that either facilitates or hinders prospects for full and healthy lives. Many of the specific health concerns participants attributed to poor housing echo existing epidemiological research findings. These findings suggest that housing may be a key intervention point for improving the health of urban Aboriginal Australians
Fast flotation in a reflux flotation cell
No full textThe research undertaken in this study was based on a novel flotation device, the Reflux Flotation Cell (RFC). This system consists of multiple parallel inclined channels positioned below a vertical chamber. The inclined channels provide an effective increase in the cross-sectional area of the vessel, thus permitting enhanced bubble-liquid segregation efficiency when the bubbles are conveyed into the inclined channels. In this thesis, fast flotation is defined as simultaneously maximising three fundamental flotation aspects: the kinetics for particle collection by bubbles, the supply of bubble surface area flux for particle extraction, and the segregation of the fine bubbles from the tailings flow. Only one or two aspects can be addressed effectively using conventional flotation systems, hence those systems are constrained by the rate limiting aspect. The RFC, however, offers the potential to achieve increases in all three areas, meaning the concept of Fast Flotation can be achieved, delivering very high flotation rates per unit of vessel area. The study firstly addressed the hydrodynamics of the RFC. Drift flux theory was used to describe the performance of the conventional vertical flotation column, predicting the theoretical gas flux, liquid flux, and the bubble surface area flux under the flooding condition. The capacity advantage, developed from the Reflux Classifier to describe the enhanced processing rate using inclined channels, is utilised to estimate the enhancement of bubble surface area flux. The theory showed the bubble surface area flux of the RFC could be increased to well beyond the typical levels of conventional flotation systems under flooding condition. A series of experiments was conducted using the laboratory RFC based on the bubble-liquid system. The experimental work achieved a bubble surface area flux of about 600 m²/m²/s, more than an order of magnitude larger than achieved in conventional flotation. Another series of experiments, having the same operating conditions as in the RFC system, involved the use of a vertical column. Extreme gas fluxes of up to 5.5 cm/s, and feed fluxes of up to 16 cm/s were applied, significantly higher than the conventional operating ranges. The results showed the inclined channels greatly enhanced the bubble-liquid segregation, preserving the fraction of feed liquid reporting to overflow to well below 24%. By comparison, 50% to 80% of the feed liquid was conveyed to the overflow using the vertical column, driven by the need to prevent bubbles reporting to the underflow, thus exhibiting very inefficient segregation.
Hydrodynamic investigation of the RFC system showed great potential to achieve fast flotation. Thus the second part of the study involved the processing of low pulp density fine coal slurries collected from the overflow of the hydrocyclone in a coal preparation plant. Three slurry pulp densities of 0.34 wt%, 3.0 wt%, and 5.2 wt% were processed. Very high feed fluxes in the range of 10 to 12 cm/s, more than ten times higher than the typical level of conventional flotation, and high gas fluxes from 2 to 6 cm/s were used. Combustible recoveries between 66% and 78% were obtained for the extremely low feed pulp density of 0.34 wt%. A near complete recovery of 98% was achieved for the coarser particles above 38 µm. By increasing the feed pulp density, the overall combustible recoveries were largely maintained, reaching up to 86%, while there was a decline in the recovery of the particles above 38 µm. The underflow discharging rate, affecting the overflow rate and the overflow liquid split (fraction of feed liquid reporting to overflow), determined the amount of gangue particles transported to product. The product ash was reduced by increasing the underflow rate, leading to a product ash of 18%, well below the feed ash of about 50%. The rejection of the mineral matter increased almost linearly as the overflow liquid split was decreased. The final part of the thesis was concerned with the flotation kinetics within a single channelled downcomer. The drift flux model was utilised to analyse the bubble volume fraction of the two-phase downward flow by varying the gas flux and the liquid flux. Graphical analysis of the drift flux curve and operating lines showed the bubble volume fraction in the flow was reduced with an increase in the liquid flux and a decrease in the gas flux. The flotation performance of three downcomer channel gaps of 2 mm, 4.5 mm, and 9 mm, were experimentally examined using a clean coal feed. The bubble-particle interaction in the downcomer was affected by the shear rate and the fluid turbulence inside the downcomer channel for a given gas flux and feed flux. The investigation of partition numbers showed that the particle recovery for a given particle size was improved with increasing gas flux, and decreasing feed flux for the narrower downcomer channel gaps of 2 mm and 4.5 mm. For a given feed flux and gas flux in the downcomer, higher particle recovery was achieved using the downcomer channel gaps of 2 mm and 4.5 mm. The first-order kinetic constant in the downcomer was obtained using a plug flow model. The downcomer kinetic constant was related to the particle size, the gas flux and feed flux in the downcomer. The correlations of the downcomer kinetic constant with the particle size, the downcomer gas flux and the downcomer feed were developed to provide a consistent basis for assessing the recovery performance for the three downcomer channel dimensions. The 2 mm and 4.5 mm channelled downcomers showed superiority for a wide range of feed fluxes when using high gas fluxes
Kinematics that differentiate the beach flags start between elite and non-elite sprinters
No full textThis study differentiated the kinematics of the beach flags sprint start between five elite (three males, two females; age = 21.2 ± 2.6 years; height = 1.71 ± 0.04 m; mass = 66.2 ± 5.9 kg) and five non-elite (three males, two females; age = 20.4 ± 1.7 years; height = 1.69 ± 0.08 meters [m]; mass = 61.6 ± 5.7 kilograms) sprinters. A high-speed camera filmed the start. Timing gates recorded the 0-2, 0-5, and 0-20 m intervals. Data included body position during the start and at take-off; start time; first step length; and sprint times. A Mann-Whitney U-test determined significant (p < 0.05) between-group differences; effect sizes (ES) were also calculated. Elite sprinters had a greater take-off trajectory angle (p = 0.01; ES = 2.57), and were faster over the 0-2 (p = 0.02; ES = 1.77), 0-5 (p = 0.05; ES = 1.20), and 0-20 m (p = 0.02; ES = 1.83) intervals. Large effects were found for: greater take-off swing leg hip flexion (ES = 1.13) and trunk lean (ES = 1.37); longer duration start time (ES = 1.33); and longer first step length (ES = 1.23) in elite sprinters. A longer start time assists with force generation, which in conjunction with increased hip flexion, could translate to a longer first step. Increased trunk lean shifts the take-off trajectory angle towards the horizontal. A greater trajectory angle at start take-off, which could be advantageous for force production during sprint performance, is likely necessary for beach flags
The influence of material cohesion on the loads exerted on support structures buried in stockpiles
No full textExperimental tests were undertaken using two different bulk materials to investigate the load conditions on support structures buried in stockpiles, such as trestle legs or columns to support load-out conveyors or roof structures of bulk solids storage sheds, respectively. These structures are widely used in large bulk storage facilities, and they are subject to significant loads exerted by the surrounding bulk solids. A theoretical approach for the analysis of these loads has been published by Roberts [1], and a correlated investigation using numerical simulation methods has been reported in Katterfeld and Roberts' study [2]. Results of both studies were in good agreement with the theoretical predictions. However, further experimental verification is needed, especially with regard to the influence of the flow properties on the stress states developed in the stored material surrounding the buried structures. Two different bulk materials, cohesive iron ore fines and free-flowing sand, were used in the experiments on a laboratory scale test rig. Tekscan tactile pressure sensors were employed on both the front face and rear face of the buried column, and pressure measurements were performed with the column located at two different positions: (I) the normal vector of the column front face is parallel to the flow direction; (II) the normal vector of the column front face is perpendicular to the flow direction. A series of stockpile tests were analysed, and the results further confirm those design equations, especially for the pressure on the rear face of the buried column