Numerical study of impact forces on railway sleepers under wheel flat

Wheel-rail interaction is one of the most important research topics in railway engineering. It includes track vibration, track impact response and safety of the track. Track structure failures caused by impact forces can lead to significant economic loss for track owners through damage to rails and to the sleepers beneath. The wheel-rail impact forces occur because of imperfections on the wheels or rails such as wheel flats, irregular wheel profile, rail corrugation and differences in the height of rails connected at a welded joint. The vehicle speed and static wheel load are important factors of the track design, because they are related to the impact forces under wheel-rail defects. In this paper, a 3-Dimensional finite element model for the study of wheel flat impact is developed by use of the FEA software package ANSYS. The effects of the wheel flat to impact force on sleepers with various speeds and static wheel loads under a critical wheel flat size are investigated. It has found that both wheel-rail impact force and impact force on sleeper induced by wheel flat are varying nonlinearly by increasing the vehicle speed; both impact forces are nonlinearly and monotonically increasing by increasing the static wheel load. The relationships between both of impact forces induced by wheel flat and vehicles speed or static load are important to the track engineers to improve the design and maintenance methods in railway industry.

A non-linear dynamic analysis of heavy haul track line sleepers under wheel flat

Significant wheel-rail dynamic forces occur because of imperfections in the wheels and/or rail. One of the key responses to the transmission of these forces down through the track is impact force on the sleepers. Dynamic analysis of nonlinear systems is very complicated and does not lend itself easily to a classical solution of multiple equations. Trying to deduce the behaviour of track components from experimental data is very difficult because such data is hard to obtain and applies to only the particular conditions of the track being tested. The finite element method can be the best solution to this dilemma. This paper describes a finite element model using the software package ANSYS for various sized flat defects in the tread of a wheel rolling at a typical speed on heavy haul track. The paper explores the dynamic response of a prestressed concrete sleeper to these defects.

A dynamic wheel-rail impact analysis of railway track under wheel flat by Finite Element Analysis

Wheel–rail interaction is one of the most important research topics in railway engineering. It involves track impact response, track vibration and track safety. Track structure failures caused by wheel–rail impact forces can lead to significant economic loss for track owners through damage to rails and to the sleepers beneath. Wheel–rail impact forces occur because of imperfections in the wheels or rails such as wheel flats, irregular wheel profiles, rail corrugations and differences in the heights of rails connected at a welded joint. A wheel flat can cause a large dynamic impact force as well as a forced vibration with a high frequency, which can cause damage to the track structure. In the present work, a three-dimensional (3-D) finite element (FE) model for the impact analysis induced by the wheel flat is developed by use of the finite element analysis (FEA) software package ANSYS and validated by another validated simulation. The effect of wheel flats on impact forces is thoroughly investigated. It is found that the presence of a wheel flat will significantly increase the dynamic impact force on both rail and sleeper. The impact force will monotonically increase with the size of wheel flats. The relationships between the impact force and the wheel flat size are explored from this finite element analysis and they are important for track engineers to improve their understanding of the design and maintenance of the track system.

Making mentoring explicit : articulating pedogogical knowledge practices

Mentoring pedagogical knowledge is fundamental towards developing preservice teachers’ practices. As a result of a train-the-trainer mentoring program, this study aimed to understand how mentors’ engagement in a professional development program on mentoring contributes to their mentoring of pedagogical knowledge practices. This qualitative research analyses the mentoring of pedagogical knowledge from six paired mentor teachers and preservice teachers (n=12) after a four-week professional school experience. Findings indicated the train-the-trainer model was successful for mentoring pedagogical knowledge on 10 of the 11 advocated practices. This suggested that a well-constructed professional development program on mentoring can advance the quality of mentoring for enhancing preservice teachers’ practices.

Low vitamin B12 levels among newly-arrived refugees from Bhutan, Iran and Afghanistan : a multicentre Australian study

Background: Vitamin B12 deficiency is prevalent in many countries of origin of refugees. Using a threshold of 5% above which a prevalence of low Vitamin B12 is indicative of a population health problem, we hypothesised that Vitamin B12 deficiency exceeds this threshold among newly-arrived refugees resettling in Australia, and is higher among women due to their increased risk of food insecurity. This paper reports Vitamin B12 levels in a large cohort of newly arrived refugees in five Australian states and territories. Methods: In a cross-sectional descriptive study, we collected Vitamin B12, folate and haematological indices on all refugees(n = 916; response rate 94% of eligible population) who had been in Australia for less than one year, and attended one of the collaborating health services between July 2010 and July 2011. Results: 16.5% of participants had Vitamin B12 deficiency (,150 pmol/L). One-third of participants from Iran and Bhutan, and one-quarter of participants from Afghanistan had Vitamin B12 deficiency. Contrary to our hypothesis, low Vitamin B12 levels were more prevalent in males than females. A higher prevalence of low Vitamin B12 was also reported in older age groups in some countries. The sensitivity of macrocytosis in detecting Vitamin B12 deficiency was only 4.6%. Conclusion: Vitamin B12 deficiency is an important population health issue in newly-arrived refugees from many countries. All newly-arrived refugees should be tested for Vitamin B12 deficiency. Ongoing research should investigate causes,treatment, and ways to mitigate food insecurity, and the contribution of such measures to enhancing the health of the refugee communities.

Years lived with disability (YLDs) for 1160 sequelae of 289 diseases and injuries 1990–2010 : a systematic analysis for the Global Burden of Disease Study 2010

Background Non-fatal health outcomes from diseases and injuries are a crucial consideration in the promotion and monitoring of individual and population health. The Global Burden of Disease (GBD) studies done in 1990 and 2000 have been the only studies to quantify non-fatal health outcomes across an exhaustive set of disorders at the global and regional level. Neither effort quantified uncertainty in prevalence or years lived with disability (YLDs). Methods Of the 291 diseases and injuries in the GBD cause list, 289 cause disability. For 1160 sequelae of the 289 diseases and injuries, we undertook a systematic analysis of prevalence, incidence, remission, duration, and excess mortality. Sources included published studies, case notification, population-based cancer registries, other disease registries, antenatal clinic serosurveillance, hospital discharge data, ambulatory care data, household surveys, other surveys, and cohort studies. For most sequelae, we used a Bayesian meta-regression method, DisMod-MR, designed to address key limitations in descriptive epidemiological data, including missing data, inconsistency, and large methodological variation between data sources. For some disorders, we used natural history models, geospatial models, back-calculation models (models calculating incidence from population mortality rates and case fatality), or registration completeness models (models adjusting for incomplete registration with health-system access and other covariates). Disability weights for 220 unique health states were used to capture the severity of health loss. YLDs by cause at age, sex, country, and year levels were adjusted for comorbidity with simulation methods. We included uncertainty estimates at all stages of the analysis. Findings Global prevalence for all ages combined in 2010 across the 1160 sequelae ranged from fewer than one case per 1 million people to 350 000 cases per 1 million people. Prevalence and severity of health loss were weakly correlated (correlation coefficient −0·37). In 2010, there were 777 million YLDs from all causes, up from 583 million in 1990. The main contributors to global YLDs were mental and behavioural disorders, musculoskeletal disorders, and diabetes or endocrine diseases. The leading specific causes of YLDs were much the same in 2010 as they were in 1990: low back pain, major depressive disorder, iron-deficiency anaemia, neck pain, chronic obstructive pulmonary disease, anxiety disorders, migraine, diabetes, and falls. Age-specific prevalence of YLDs increased with age in all regions and has decreased slightly from 1990 to 2010. Regional patterns of the leading causes of YLDs were more similar compared with years of life lost due to premature mortality. Neglected tropical diseases, HIV/AIDS, tuberculosis, malaria, and anaemia were important causes of YLDs in sub-Saharan Africa. Interpretation Rates of YLDs per 100 000 people have remained largely constant over time but rise steadily with age. Population growth and ageing have increased YLD numbers and crude rates over the past two decades. Prevalences of the most common causes of YLDs, such as mental and behavioural disorders and musculoskeletal disorders, have not decreased. Health systems will need to address the needs of the rising numbers of individuals with a range of disorders that largely cause disability but not mortality. Quantification of the burden of non-fatal health outcomes will be crucial to understand how well health systems are responding to these challenges. Effective and affordable strategies to deal with this rising burden are an urgent priority for health systems in most parts of the world. Funding Bill & Melinda Gates Foundation.

Psychological wellbeing of refugees resettling in Australia : a literature review prepared for the Australian Psychological Society

This literature review was developed as background for the formulation of an Australian Psychological Society position on the mental health and wellbeing of refugees resettling in Australia. The major aim is to provide a broad overview of the concerns related to refugee mental health and wellbeing within the Australian context. To begin, a brief overview of the definition of a refugee and the scope of refugee movement is provided. Next, the review examines the pre-displacement, post-displacement, systemic and socio-political factors that influence the process of adaptation in refugee resettlement. It then reviews documented approaches to psychological assessment and therapeutic interventions with refugees; and finally it summarises suggestions for assessment and intervention in these practice contexts.

The emergence of critical health psychology : can it contribute to promoting public health?

The purpose of this article is twofold : first to provide an overview of the emergence of critical health psychology for those working in the related social and health sciences and as a review of its major developments for health psychology; and second to discuss critically the potential for critical health psychology to contribute to promoting public health with specific reference to the directives espoused by Prilleltensky (2003) and Murray and Campbell (2003). The identification of three philosophical phases of the emergence of critical health psychology is used to examine the directions of the field and the challenges facing critical health psychology in order to contribute to public and global health.

Why are children the most important audience for pornography in Australia?

Who watches pornography in Australia? If you listen to public debates about the genre the answer is clear – it’s children. Children are accessing pornography on smartphones (Murray and Tin 2011). Children are taking ‘lewd’ photographs of themselves, creating their own pornography (Nelligan and Etheridge 2011). Indigenous Australian children must be protected by banning pornography (the Age 2011). Pornographic magazines are placed where children can see them (O'Rourke 2011). Exposure to pornography is damaging children (Sundstrom 2011). The Australian Government insists that the Internet must be filtered to protect children from pornography (Collerton 2010). And if indeed any adults are watching pornography in Australia, then it’s child pornography (MacDonald 2011; Ralston and Howden 2011).In story after story, public debate about pornography focuses on children as its audience. There is no suggestion that children are numerically the largest audience of pornography in Australia. But emphatically the suggestion is that children are the most important audience to be taken into account when thinking about the genre. This chapter explores why this is the case, and notes the political advantages and disadvantages of focusing on children as the most important audience for pornography in Australia.

Intracellular trafficking and secretion of inflammatory cytokines

The secretion of cytokines by immune cells plays a significant role in determining the course of an inflammatory response. The levels and timing of each cytokine released are critical for mounting an effective but confined response, whereas excessive or dysregulated inflammation contributes to many diseases. Cytokines are both culprits and targets for effective treatments in some diseases. The multiple points and mechanisms that have evolved for cellular control of cytokine secretion highlight the potency of these mediators and the fine tuning required to manage inflammation. Cytokine production in cells is regulated by cell signaling, and at mRNA and protein synthesis levels. Thereafter, the intracellular transport pathways and molecular trafficking machinery have intricate and essential roles in dictating the release and activity of cytokines. The trafficking machinery and secretory (exocytic) pathways are complex and highly regulated in many cells, involving specialized membranes, molecules and organelles that enable these cells to deliver cytokines to often-distinct areas of the cell surface, in a timely manner. This review provides an overview of secretory pathways - both conventional and unconventional - and key families of trafficking machinery. The prevailing knowledge about the trafficking and secretion of a number of individual cytokines is also summarized. In conclusion, we present emerging concepts about the functional plasticity of secretory pathways and their modulation for controlling cytokines and inflammation.

An Introduction to Dating Techniques : A Guide for Geomorphologists

This chapter provides researchers with a guide to some of the types of dating techniques that can be used in geomorpological investigations and issues that need to be addressed when using gechronological data, specifically issues relating to accuracy and precision. This chapter also introduces the 'types' of dating methods that are commonly used in geomorphological studies. This includes sidereal, isotopic, radiogenic, and chemical dating methods.

Organisational innovativeness : the role of strategic orientation and environmental scanning

This study examined the effects of strategic orientation and environmental scanning on a firm’s propensity to innovate (organisational innovativeness). Previous research has mostly proposed descriptive and theoretical relationships between strategic orientation, environmental scanning and organisational innovation adoption (Beal, 2000; Jennings & Lumpkin, 1992; Raymond, Julien, & Ramangalahy, 2001). However, strategic orientation and environmental scanning, as distinct constructs, have not been empirically examined directly before in relation to organisational innovativeness. Furthermore the directionality of the relationship between strategic orientation and environmental scanning on organisational innovation adoption is still unclear (Hagen, Haile, & Maghrabi, 2003). For example, does scanning the environment result in certain types of organisational strategies, and these strategies in turn influence levels of organisational innovativeness? Or do certain types of strategic orientations pre-determine the levels of environmental scanning, and then this environmental scanning influences an organisation’s propensity to innovate? Therefore, this study using a more nuanced measure of strategic orientation; the Venkatraman’s (1989) STROBE framework of analysis, defensiveness, futurity, proactiveness, aggressiveness and riskiness, examined the directional effects of strategy and environmental scanning on organisational innovativeness Specifically, two competing models of directionality between strategic orientation and environmental scanning in relation to organisational innovativeness were proposed. Model 1 (Behavioural View) proposed that certain strategic orientation dimensions affect levels of environmental scanning, which in turn influences organisational innovativeness. In contrast, Model 2 (Open Systems view) proposed that environmental scanning affects the emphasis on certain strategic orientation dimensions, which in turn influences organisational innovativeness. Data was collected from 117 industrial firms and path analyses were used to test the two competing models. The results supported both models, suggesting a bi-directional relationship, as both models had adequate fit indices and significant paths with the data. However, overall Model 2 – the Open Systems Model had the stronger fit indices and stronger indirect effect compared to Model 1 – the Behavioural Model, suggesting that overall environmental scanning does not exert a strong direct effect on innovativeness but has more of a stronger indirect effect through the analysis and proactiveness strategic orientation dimensions. In sum, the thesis results suggest that firms’ that emphasise environmental scanning – that is continually seeking information from the environment about customers, markets, industry and new technology - are more likely to emphasise strategic orientations such as proactiveness – being innovative - and also analysis – being analytical and comprehensive in decision making - and both these strategic orientations in turn greatly influence these firms’ propensity to innovate. Discussion is given to these findings and implications are drawn for organisations and future research.

“Lay” theories of anorexia nervosa : a discourse analytic study

Previous studies on lay theories of anorexia nervosa have examined the ‘accuracy’ of lay knowledge, and the identification of factors by family and friends that would encourage early interventions (Huon, Brown, & Morris, 1988, 7, 239–252; Murray, Touyz, & Beumont, 1990, 9, 87–93). In contrast to these approaches, we examine lay theories of anorexia nervosa using a critical psychology perspective. We argue that the use of a discourse analysis methodology enables the examination of the construction of lay theories through dominant concepts and ideas. Ten semi-structured interviews with five women and five men aged between 15 and 25 years were carried out. Participants were asked questions about three main aspects of anorexia nervosa: aetiology, treatment and relationship to gender. Each interview was analysed in terms of the structure, function and variability of discourse. Three discourses: sociocultural, individual and femininity, are discussed in relation to the interview questions. We conclude that, in this study, lay theories of anorexia nervosa were structured through key discourses that maintained a separation between sociocultural aspects of anorexia nervosa and individual psychology. This separation exists in dominant psychomedical conceptualizations of anorexia nervosa, reinforcing the concept that it is a form of psychopathology.