Application of high voltage, high frequency pulsed electromagnetic field on cortical bone tissue

Over the last few decades, electric and electromagnetic fields have achieved important role as stimulator and therapeutic facility in biology and medicine. In particular, low magnitude, low frequency, pulsed electromagnetic field has shown significant positive effect on bone fracture healing and some bone diseases treatment. Nevertheless, to date, little attention has been paid to investigate the possible effect of high frequency, high magnitude pulsed electromagnetic field (pulse power) on functional behaviour and biomechanical properties of bone tissue. Bone is a dynamic, complex organ, which is made of bone materials (consisting of organic components, inorganic mineral and water) known as extracellular matrix, and bone cells (live part). The cells give the bone the capability of self-repairing by adapting itself to its mechanical environment. The specific bone material composite comprising of collagen matrix reinforced with mineral apatite provides the bone with particular biomechanical properties in an anisotropic, inhomogeneous structure. This project hypothesized to investigate the possible effect of pulse power signals on cortical bone characteristics through evaluating the fundamental mechanical properties of bone material. A positive buck-boost converter was applied to generate adjustable high voltage, high frequency pulses up to 500 V and 10 kHz. Bone shows distinctive characteristics in different loading mode. Thus, functional behaviour of bone in response to pulse power excitation were elucidated by using three different conventional mechanical tests applying three-point bending load in elastic region, tensile and compressive loading until failure. Flexural stiffness, tensile and compressive strength, hysteresis and total fracture energy were determined as measure of main bone characteristics. To assess bone structure variation due to pulse power excitation in deeper aspect, a supplementary fractographic study was also conducted using scanning electron micrograph from tensile fracture surfaces. Furthermore, a non-destructive ultrasonic technique was applied for determination and comparison of bone elasticity before and after pulse power stimulation. This method provided the ability to evaluate the stiffness of millimetre-sized bone samples in three orthogonal directions. According to the results of non-destructive bending test, the flexural elasticity of cortical bone samples appeared to remain unchanged due to pulse power excitation. Similar results were observed in the bone stiffness for all three orthogonal directions obtained from ultrasonic technique and in the bone stiffness from the compression test. From tensile tests, no significant changes were found in tensile strength and total strain energy absorption of the bone samples exposed to pulse power compared with those of the control samples. Also, the apparent microstructure of the fracture surfaces of PP-exposed samples (including porosity and microcracks diffusion) showed no significant variation due to pulse power stimulation. Nevertheless, the compressive strength and toughness of millimetre-sized samples appeared to increase when the samples were exposed to 66 hours high power pulsed electromagnetic field through screws with small contact cross-section (increasing the pulsed electric field intensity) compare to the control samples. This can show the different load-bearing characteristics of cortical bone tissue in response to pulse power excitation and effectiveness of this type of stimulation on smaller-sized samples. These overall results may address that although, the pulse power stimulation can influence the arrangement or the quality of the collagen network causing the bone strength and toughness augmentation, it apparently did not affect the mineral phase of the cortical bone material. The results also confirmed that the indirect application of high power pulsed electromagnetic field at 500 V and 10 kHz through capacitive coupling method, was athermal and did not damage the bone tissue construction.

Serious playground : using Second Life to engage high school students in urban planning

Virtual world platforms such as Second Life have been successfully used in educational contexts to motivate and engage learners. This article reports on an exploratory workshop involving a group of high school students using Second Life for an urban planning project. Young people are traditionally an under-represented demographic when it comes to participating in urban planning and decision making processes. The research team developed activities that combined technology with a constructivist approach to learning. Real world experiences and purposes ensured that the workshop enabled students to see the relevance of their learning. Our design also ensured that play remained an important part of the learning. By conceiving of the workshop as a ‘serious playground’ we investigated the ludic potential of learning in a virtual world.

Experiences of neighbourhood walkability among older Australians living in high density inner-city areas

Walking as an out-of-home mobility activity is recognised for its contribution to healthy and active ageing. The environment can have a powerful effect on the amount of walking activity undertaken by older people, thereby influencing their capacity to maintain their wellbeing and independence. This paper reports the findings from research examining the experiences of neighbourhood walking for 12 older people from six different inner-city high density suburbs, through analysis of data derived from travel diaries, individual time/space activity maps (created via GPS tracking over a seven-day period and GIS technology), and in-depth interviews. Reliance on motor vehicles, the competing interests of pedestrians and cyclists on shared pathways and problems associated with transit systems, public transport, and pedestrian infrastructure emerged as key barriers to older people venturing out of home on foot. GPS and GIS technology provide new opportunities for furthering understanding of the out-of-home mobility of older populations.

Behavioural beliefs concerning gender and high-risk sexual behaviours in the context of HIV/AIDS in PNG : views from within teacher education

Education is often viewed as a key approach to address sexual-health issues; the current concern is the burgeoning HIV/AIDS epidemic. This ethnographic study investigates the gender practices associated with high-risk sexual behaviour in Papua New Guinea as viewed by educators there. A number of practices, including gender inequality and associated sexual behaviours have been highlighted by male and female participants as escalating PNG’s HIV/AIDS epidemic. The study finds that although participants were well-informed concerning HIV/AIDS, they had varying beliefs concerning the prevailing gender/sexual issues involved in escalating highrisk behaviour and how to address the problem. The study further examines the behavioural beliefs and intentions of the educators themselves. Subsequently, within the data a number of underpinning factors, pertaining to gender, education and life experience, were found to be related to the behaviour beliefs and intentions of participants towards embracing change with regard to behaviours associated with gender equality in PNG. These factors appeared to encourage participants to adopt healthier gender and sexual behavioural intentions and, arguably, could provide the basis for ways to help address the gender inequality and high-risk behaviours associated with HIV/AIDS in PNG.

Valuation of family firms : the limitations of accounting information

This conceptual paper explores the extent to which reported accounting information captures unique family firm decision-making and intangible asset factors that impact financial value. We review the family firm valuation-relevant literature and identify that this body of research is predicated on the assumption that accounting information reflects the underlying reality of family firms. This research, however, fails to recognise that current accounting technology does not fully recognise the family firm factors in the book value of the firm or the implications for long run persistence of earnings. Thus, valuation models underpinning the extant empirical research, which are predicated on reported accounting information, may not fully reflect the intrinsic value of family firms. We present propositions on the interaction between accounting information, family factors and valuation as a road map for future empirical research with a discussion of appropriate methodologies.

Development of an innovative technology-based youth passenger safety program : an evidence-based approach

Young drivers are overrepresented in motor vehicle crash rates, and their risk increases when carrying similar aged passengers. Graduated Driver Licensing strategies have demonstrated effectiveness in reducing fatalities among young drivers, however complementary approaches may further reduce crash rates. Previous studies conducted by the researchers have shown that there is considerable potential for a passenger focus in youth road safety interventions, particularly involving the encouragement of young passengers to intervene in their peers’ risky driving (Buckley, Chapman, Sheehan & Davidson, 2012). Additionally, this research has shown that technology-based applications may be a promising means of delivering passenger safety messages, particularly as young people are increasingly accessing web-based and mobile technologies. This research describes the participatory design process undertaken to develop a web-based road safety program, and involves feasibility testing of storyboards for a youth passenger safety application. Storyboards and framework web-based materials were initially developed for a passenger safety program, using the results of previous studies involving online and school-based surveys with young people. Focus groups were then conducted with 8 school staff and 30 senior school students at one public high school in the Australian Capital Territory. Young people were asked about the situations in which passengers may feel unsafe and potential strategies for intervening in their peers’ risky driving. Students were also shown the storyboards and framework web-based material and were asked to comment on design and content issues. Teachers were also shown the material and asked about their perceptions of program design and feasibility. The focus group data will be used as part of the participatory design process, in further developing the passenger safety program. This research describes an evidence-based approach to the development of a web-based application for youth passenger safety. The findings of this research and resulting technology will have important implications for the road safety education of senior high school students.

Attitudes and expectations of technologies to manage high risk wandering and elopement in persons with dementia : an Australian perspective

Wandering is aimless and repetitive locomotion that may expose persons with dementia (PWD) to elopement, getting lost and death. This study is an Australian replication of a US study. Cross-disciplinary consensus- based analysis was applied to data from five focus groups (N =47: cognitively intact LTC residents (5), carers of PWD (11), home care workers (13) allied health professionals and health-focused engineers (7) and RNs (11). Groups received briefing about wandering monitoring and elopement management systems. Consistent with US attitudes, participants in all groups agreed on what a wandering technology should do, how it should do it, and necessary technical specifications. Within each group participants raised the need for a continuum of care for PWD and the imperative for early recognition of potentially dangerous wandering and getting lost when they occur. Global Positioning System elopement management was the preferred option. Interestingly, the prospective value of GPS to recover a lost or eloped wanderer far outweighed privacy concerns, as in the US. A pervasive theme was that technologies need to augment, but cannot replace, attentive, compassionate caregiver presence. A significant theme raised only by Australian carers of PWD was the potential for development of implantable GPS technologies and the need for public debate about attendant ethical issues. Given that 60% or more of over 200,000 Australians and 4.5 million Americans with dementia will develop wandering, there is a pressing need to develop effective locator systems that may delay institutionalization, help allay carer concern and enhance PWD safety.

Twitter as a technology for audiencing and fandom : the #Eurovision phenomenon

Amongst the most prominent uses of Twitter at present is its role in the discussion of widely televised events: Twitter’s own statistics for 2011, for example, list major entertainment spectacles (the MTV Music Awards, the BET Awards) and sports matches (the UEFA Champions League final, the FIFA Women’s World Cup final) amongst the events generating the most tweets per second during the year (Twitter, 2011). User activities during such televised events constitute a specific, unique category of Twitter use, which differs clearly from the other major events which generate a high rate of tweets per second (such as crises and breaking news, from the Japanese earthquake and tsunami to the death of Steve Jobs), as preliminary research has shown. During such major media events, by contrast, Twitter is used most predominantly as a technology of fandom instead: it serves in the first place as a backchannel to television and other streaming audiovisual media, enabling users offer their own running commentary on the universally shared media text of the event broadcast as it unfolds live. Centrally, this communion of fans around the shared text is facilitated by the use of Twitter hashtags – unifying textual markers which are now often promoted to prospective audiences by the broadcasters well in advance of the live event itself. This paper examines the use of Twitter as a technology for the expression of shared fandom in the context of a major, internationally televised annual media event: the Eurovision Song Contest. It constitutes a highly publicised, highly choreographed media spectacle whose eventual outcomes are unknown ahead of time and attracts a diverse international audience. Our analysis draws on comprehensive datasets for the ‘official’ event hashtags, #eurovision, #esc, and #sbseurovision. Using innovative methods which combine qualitative and quantitative approaches to the analysis of Twitter datasets containing several hundreds of thousands, we examine overall patterns of participation to discover how audiences express their fandom throughout the event. Minute-by-minute tracking of Twitter activity during the live broadcasts enables us to identify the most resonant moments during each event; we also examine the networks of interaction between participants to detect thematically or geographically determined clusters of interaction, and to identify the most visible and influential participants in each network. Such analysis is able to provide a unique insight into the use of Twitter as a technology for fandom and for what in cultural studies research is called ‘audiencing’: the public performance of belonging to the distributed audience for a shared media event. Our work thus contributes to the examination of fandom practices led by Henry Jenkins (2006) and other scholars, and points to Twitter as an important new medium facilitating the connection and communion of such fans.

Does teaching sequence matter when teaching high school chemistry with scientific visualisations?

Five Canadian high school Chemistry classes in one school, taught by three different teachers, studied the concepts of dynamic chemical equilibria and Le Chatelier’s Principle. Some students received traditional teacher-led explanations of the concept first and used an interactive scientific visualisation second, while others worked with the visualisation first and received the teacher-led explanation second. Students completed a test of their conceptual understanding of the relevant concepts prior to instruction, after the first instructional session and at the end of instruction. Data on students’ academic achievement (highest, middle or lowest third of the class on the mid-term exam) and gender were also collected to explore the relationship between these factors, conceptual development and instructional sequencing. Results show, within this context at least, that teaching sequence is not important in terms of students’ conceptual learning gains.

High rise residential building quality : residents satisfaction survey

It is widely recognized that the quality of design is crucial to the success of the construction or production process and fairly minor changes in design can often result in giving major effects on the cost and efficiency of production and construction as well as on the usefulness, constructability and marketability of the product especially in developing high rise residential property development. The purpose of this study is to suggest a framework model for property manager, considering the sustainable and building quality of property development in high rise residential complex. This paper evaluates and ranks the importance, and frequency of the building quality factors that affect the sustainability and comfort of living for the resident in the selected high rise residential complex in Malaysia. A total of 500 respondents consisting of 20 property managers participated in this study. The respondents were asked to indicate how important each of building equipments in giving them the comfort of living in the selected high rise residential complex. The data were then subjected to the calculation of important indices which enabled the factors to be ranked. After that, a framework model will be developed to make sure all property managers will be guided to prepare their property for the resident to stay in the complex. Accordingly, the living satisfaction by the framework model plays a meaningful role in preparing and developing sustainable and good building quality in Malaysia high rise residential complex.

RcppArmadillo : accelerating R with high-performance C++ linear algebra

The R statistical environment and language has demonstrated particular strengths for interactive development of statistical algorithms, as well as data modelling and visualisation. Its current implementation has an interpreter at its core which may result in a performance penalty in comparison to directly executing user algorithms in the native machine code of the host CPU. In contrast, the C++ language has no built-in visualisation capabilities, handling of linear algebra or even basic statistical algorithms; however, user programs are converted to high-performance machine code, ahead of execution. A new method avoids possible speed penalties in R by using the Rcpp extension package in conjunction with the Armadillo C++ matrix library. In addition to the inherent performance advantages of compiled code, Armadillo provides an easy-to-use template-based meta-programming framework, allowing the automatic pooling of several linear algebra operations into one, which in turn can lead to further speedups. With the aid of Rcpp and Armadillo, conversion of linear algebra centered algorithms from R to C++ becomes straightforward. The algorithms retains the overall structure as well as readability, all while maintaining a bidirectional link with the host R environment. Empirical timing comparisons of R and C++ implementations of a Kalman filtering algorithm indicate a speedup of several orders of magnitude.

ICT driven pedagogies and its impact on learning outcomes in high school mathematics

ICT (Information and Communication Technology) creates numerous opportunities for teachers to re-think their pedagogies. In subjects like mathematics which draws upon abstract concepts, ICT creates such an opportunity. Instead of a mimetic pedagogical approach, suitably designed activities with ICT can enable learners to engage more proactively with their learning. In this quasi-experimental designed study, ICT was used in teaching mathematics to a group of first year high school students (N=25) in Australia. The control group was taught predominantly through traditional pedagogies (N=22). Most of the variables that had previously impacted on the design of such studies were suitably controlled in this yearlong investigation. Quantitative and qualitative results showed that students who were taught by ICT driven pedagogies benefitted from the experience. Pre and post-test means showed that there was a difference between the treatment and control groups. Of greater significance was that the students (in the treatment group) believed that the technology enabled them to engage more with their learning.

Nutrient removal from wastewaters using high performance materials

Return side streams from anaerobic digesters and dewatering facilities at wastewater treatment plants (WWTPs) contribute a significant proportion of the total nitrogen load on a mainstream process. Similarly, significant phosphate loads are also recirculated in biological nutrient removal (BNR) wastewater treatment plants. Ion exchange using a new material, known by the name MesoLite, shows strong potential for the removal of ammonia from these side streams and an opportunity to concurrently reduce phosphate levels. A pilot plant was designed and operated for several months on an ammonia rich centrate from a dewatering centrifuge at the Oxley Creek WWTP, Brisbane, Australia. The system operated with a detention time in the order of one hour and was operated for between 12 and 24 hours prior to regeneration with a sodium rich solution. The same pilot plant was used to demonstrate removal of phosphate from an abattoir wastewater stream at similar flow rates. Using MesoLite materials, >90% reduction of ammonia was achieved in the centrate side stream. A full-scale process would reduce the total nitrogen load at the Oxley Creek WWTP by at least 18%. This reduction in nitrogen load consequently improves the TKN/COD ratio of the influent and enhances the nitrogen removal performance of the biological nutrient removal process.

Saturated core high-temperature superconducting fault current limiters as an alternative to conventional series reactors in a distribution grid

Series reactors are used in distribution grids to reduce the short-circuit fault level. Some of the disadvantages of the application of these devices are the voltage drop produced across the reactor and the steep front rise of the transient recovery voltage (TRV), which generally exceeds the rating of the associated circuit breaker. Simulations were performed to compare the characteristics of a saturated core High-Temperature Superconducting Fault Current Limiter (HTS FCL) and a series reactor. The design of the HTS FCL was optimized using the evolutionary algorithm. The resulting Pareto frontier curve of optimum solution is presented in this paper. The results show that the steady-state impedance of an HTS FCL is significantly lower than that of a series reactor for the same level of fault current limiting. Tests performed on a prototype 11 kV HTS FCL confirm the theoretical results. The respective transient recovery voltages (TRV) of the HTS FCL and an air core reactor of comparable fault current limiting capability are also determined. The results show that the saturated core HTS FCL has a significantly lower effect on the rate of rise of the circuit breaker TRV as compared to the air core reactor. The simulations results are validated with shortcircuit test results.