977 resultados para shock impact curve


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This paper presents a numerical study of the response of axially loaded concrete filled steel tube (CFST) columns under lateral impact loading using explicit non-linear finite element techniques. The aims of this paper are to evaluate the vulnerability of existing columns to credible impact events as well as to contribute new information towards the safe design of such vulnerable columns. The model incorporates concrete confinement, strain rate effects of steel and concrete, contact between the steel tube and concrete and dynamic relaxation for pre-loading, which is a relatively recent method for applying a pre-loading in the explicit solver. The finite element model was first verified by comparing results with existing experimental results and then employed to conduct a parametric sensitivity analysis. The effects of various structural and load parameters on the impact response of the CFST column were evaluated to identify the key controlling factors. Overall, the major parameters which influence the impact response of the column are the steel tube thickness to diameter ratio, the slenderness ratio and the impact velocity. The findings of this study will enhance the current state of knowledge in this area and can serve as a benchmark reference for future analysis and design of CFST columns under lateral impact.

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Background: Providing motivationally supportive physical education experiences for learners is crucial since empirical evidence in sport and physical education research has associated intrinsic motivation with positive educational outcomes. Self-determination theory (SDT) provides a valuable framework for examining motivationally supportive physical education experiences through satisfaction of three basic psychological needs: autonomy, competence and relatedness. However, the capacity of the prescriptive teaching philosophy of the dominant traditional physical education teaching approach to effectively satisfy the psychological needs of students to engage in physical education has been questioned. The constraints-led approach (CLA) has been proposed as a viable alternative teaching approach that can effectively support students’ self-motivated engagement in physical education. Purpose: We sought to investigate whether adopting the learning design and delivery of the CLA, guided by key pedagogical principles of nonlinear pedagogy (NLP), would address basic psychological needs of learners, resulting in higher self-reported levels of intrinsic motivation. The claim was investigated using action research. The teacher/researcher delivered two lessons aimed at developing hurdling skills: one taught using the CLA and the other using the traditional approach. Participants and Setting: The main participant for this study was the primary researcher and lead author who is a PETE educator, with extensive physical education teaching experience. A sample of 54 pre-service PETE students undertaking a compulsory second year practical unit at an Australian university was recruited for the study, consisting of an equal number of volunteers from each of two practical classes. A repeated measures experimental design was adopted, with both practical class groups experiencing both teaching approaches in a counterbalanced order. Data collection and analysis: Immediately after participation in each lesson, participants completed a questionnaire consisting of 22 items chosen from validated motivation measures of basic psychological needs and indices of intrinsic motivation, enjoyment and effort. All questionnaire responses were indicated on a 7-point Likert scale. A two-tailed, paired-samples t-test was used to compare the groups’ motivation subscale mean scores for each teaching approach. The size of the effect for each group was calculated using Cohen’s d. To determine whether any significant differences between the subscale mean scores of the two groups was due to an order effect, a two-tailed, independent samples t test was used. Findings: Participants’ reported substantially higher levels of self-determination and intrinsic motivation during the CLA hurdles lesson compared to during the traditional hurdles lesson. Both groups reported significantly higher motivation subscale mean scores for competence, relatedness, autonomy, enjoyment and effort after experiencing the CLA than mean scores reported after experiencing the traditional approach. This significant difference was evident regardless of the order that each teaching approach was experienced. Conclusion: The theoretically based pedagogical principles of NLP that inform learning design and delivery of the CLA may provide teachers and coaches with tools to develop more functional pedagogical climates, which result in students exhibiting more intrinsically motivated behaviours during learning.

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This large-scale longitudinal population study provided a rare opportunity to consider the interface between multilingualism and speech-language competence on children’s academic and social-emotional outcomes and to determine whether differences between groups at 4 to 5 years persist, deepen, or disappear with time and schooling. Four distinct groups were identified from the Kindergarten cohort of the Longitudinal Study of Australian Children (LSAC) (1) English-only + typical speech and language (n = 2,012); (2) multilingual + typical speech and language (n = 476); (3) English-only + speech and language concern (n = 643); and (4) multilingual + speech and language concern (n = 109). Two analytic approaches were used to compare these groups. First, a matched case-control design was used to randomly match multilingual children with speech and language concern (group 4, n = 109) to children in groups 1, 2, and 3 on gender, age, and family socio-economic position in a cross-sectional comparison of vocabulary, school readiness, and behavioral adjustment. Next, analyses were applied to the whole sample to determine longitudinal effects of group membership on teachers’ ratings of literacy, numeracy, and behavioral adjustment at ages 6 to 7 and 8 to 9 years. At 4 to 5 years, multilingual children with speech and language concern did equally well or better than English-only children (with or without speech and language concern) on school readiness tests but performed more poorly on measures of English vocabulary and behavior. At ages 6 to 7 and 8 to 9, the early gap between English-only and multilingual children had closed. Multilingualism was not found to contribute to differences in literacy and numeracy outcomes at school; instead, outcomes were more related to concerns about children’s speech and language in early childhood. There were no group differences for socio-emotional outcomes. Early evidence for the combined risks of multilingualism plus speech and language concern was not upheld into the school years.

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Background Psychological distress is well-documented worldwide among medical and dental students. Few studies have assessed the impact of self-development coaching programs on the students’ psychological health. The aim of the study was to evaluate the effect of a self-development coaching programme on the psychological health and academic performance of preclinical medical and dental students at Umm Al-Qura University, Saudi Arabia. Methods Four-hundred and twenty-two participants (n = 422, 20–22 years) fulfilled the study requirements and were invited into a parallel-randomised controlled trial that was partially blinded. Participants were stratified by faculty, gender, and academic year, and then randomised. A total of 156 students participated in the intervention group (IG) and 163 students participated in the control group (CG). The IG received the selfdevelopment programme, involving skills and strategies aimed to improve students’ psychological health and academic performance, through a two-day workshop. Meanwhile, the CG attended an active placebo programme focussing on theoretical information that was delivered through a five-hour workshop. Both programmes were conducted by the same presenter during Week 1 of the second semester of the 2012–2013 academic year. Data were gathered immediately before (T1), one week after (T2) and five weeks (T3) after the intervention. Psychological health was measured using the Depression Anxiety Stress Scale (DASS-21), the General Self-Efficacy (GSE), and the Satisfaction With Life Scale (SWLS). Academic performance was measured using students’ academic weighted grades (WG). Student cognitive and emotional perceptions of the intervention were measured using the Credibility/Expectancy Questionnaire (CEQ). Results Data from 317 students, who completed the follow ups, were analysed across the three time periods (IG, n = 155; CG, n = 162). The baseline variables and demographic data of the IG and CG were not significantly different. The IG showed short-term significant reductions in depression and anxiety in compared to CG from T1 to T2. The short-term changes in stress, GSE and SWLS of the IG were not significantly different from those of the CG. While both groups showed a significant change on most of the psychological variables from T1 to T3, no significant differences were found between the groups in this period. In addition, no significant difference was found in WG between the IG and CG after the intervention. No harms relevant to the intervention were reported. Conclusion The investigated self-development coaching programme showed only a short-term improvement on depression and anxiety compared with an active control. There was no effect of the intervention on academic performance.

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This qualitative study of parent-child communication examined the views of parents and children in a province of Saudi Arabia concerning how family interactions, parental authority and children’s behaviours are affected by the globalising influences of media and technology. Impacts reported include how tension in family communication arises as children develop a hybrid culture through accessing Western ideas and ideologies that are profoundly challenging to traditional Islamic culture.

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Past research on early internationalising firms often examined factors and motivations potentially influencing internationalisation activities separately. The purpose of this paper was to investigate a set of indicators and their interplay with each other. Firstly, the impact of (a) international potential in the form of the depth and diversity of international experience and network contacts was investigated. Secondly, it was examined to what extent (b) motivational factors and (c) firm stages affect the relationship between international potential and internationalisation activities. This paper used longitudinal data from the Comprehensive Australian Study of Entrepreneurial Emergence (CAUSEE). Results suggest that the international potential of a new venture as a whole is a significant determinant of subsequent internationalisation activities. However, having a diverse international experience from a variety of foreign countries appears to be more beneficial than a long-lasting experience from only a limited number of foreign countries. Furthermore, analyses showed that the interplay of high growth ambitions and the depth of international experience positively affect internationalisation activities. Opportunity or necessity driven entrepreneurship, however, neither exaggerate nor weaken the positive relationship between international potentials and internationalisation activities. Similarly, no moderation by firm stages was found.

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A novel protective covering with a layered and staggered structure was proposed to protect concrete against projectile impact. Experimental study was conducted to investigate the ballistic behaviour of the concrete targets against 12.7 mm armour-piercing incendiary projectile at velocities ranging from 537.7 to 596.5 m/s. The results showed that the concrete targets with protective covering exhibited superior integrity with no damage on the distal surface, whereas the concrete targets without protective covering were fractured with penetrating cracks throughout the thickness of the target. Moreover, the protected concrete targets displayed significantly reduced penetration depth compared with the concrete targets without protective covering. The protective covering with epoxy adhesive interlayers had a bigger protection factor than that with silicone sealant interlayers, but the former suffered more severe damage than the latter.

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Arts culture organisations and funding authorities increasingly need to evaluate the impact of festivals, events and performances. Economic impacts are often privileged over 'soft data' about community experience and engagement. This new book offers a timely and scholarly demonstration of how cultural value and impact can be evaluated. It offers an innovative approach whereby the relationship developed between the researchers/evaluator and the commissioning arts and cultural producer provides an opportunity to rethink the traditional process of reporting back on value and impact through the singular entity of funds acquittal. Using three commissioned evaluations undertaken at an Australian university as an extended case study, the book investigates the two positions most often adopted by researchers/evaluators - embedded and collaborative, or external and distanced - and argues the merits and deficiencies of the two approaches. Offering an examination of how arts evaluation 'works' in theory and practice and more importantly, why it is needed now and in the future to demonstrate the reach and cultural gains from arts and cultural projects, this will be essential reading for students in arts management, professionals working in arts and cultural organisations, scholars working in association with creative industries and cultural development.

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A longitudinal qualitative study was conducted with CEOs of 12 fundraising organisations across Australia to answer the question - how mights a change in the CEO's fundraising knowledge improve fundraising activity and outcomes for their organisation? The CEOs along with the inaugural Australian Grantmaker of the Year, Caitriona Fay from Perpetual and lead researcher Dr Wendy Scaife travelled to San Antonio, Texas, USA to attend the annual Association of Fundraising Professionals (AFP) conference in March 2014. Participants identified five main success factors for such group learning initiatives about fundraising: - Getting away from the day to day business of running the organisation - Informal, social time to debrief and get to know others - Diversity of organisations whereby no one was in direct competition to others - Commitment, openness and willingness of individuals to participate - Group facilitation This research has been supported by the Perpetual Foundation – Trustees Endowment, The Edward Corbould Charitable Trust, and the Samuel and Eileen Gluyas Charitable Trust under the management of Perpetual Trustee Company Ltd.

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Although it seems reasonable to assume that activating patriotism might motivate citizens to cooperate with the state in reaching societal goals, the empirical evidence supporting this contention is based mostly on correlational rather than experimental studies. In addition, little is known on whether patriotism can be manipulated without simultaneously triggering nationalism and on the psychological processes which determine the patriotism-cooperation relation. This current article reports results of one survey and three experiments that manipulate patriotism by displaying either a national flag or national landscapes or by priming national achievements. The outcomes indicate that reported and manipulated patriotism indirectly increase tax compliance, although the national flag also increases nationalism. National achievements, on the other hand, seemingly increases trust in national public institutions and the voluntary motivation to cooperate, whereas national landscapes only increase the voluntary motivation to cooperate. Hence, it is possible to increase social capital in the form of trust and cooperation through patriotism without fostering nationalism as well.

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Objectives Mental health workers are constantly exposed to their clients’ stories of distress and trauma. While listening to these stories can be emotionally draining, professionals in this field still derive pleasure from their work. This study examined the role of personality and workplace belongingness in predicting compassion satisfaction, secondary traumatic stress, and burnout in mental health professionals. Methods Mental health staff (N = 156) working in a counselling service completed a questionnaire that included measures relating to professional quality of life, the Five-Factor Model of personality, workplace belongingness, as well as questions relating to the participants’ demographic profile, work roles and trauma history. Results The results indicated that, high levels of emotional stability (low neuroticism), extraversion, agreeableness, conscientiousness, and being connected at work, are essential factors that promote the professional quality of life of mental health workers. Specifically, workplace belongingness was the strongest predictor of compassion satisfaction and low levels of burnout, while neuroticism was the strongest predictor of secondary traumatic stress. Conclusions Important implications from this study include: (1) encouraging mental health staff to increase self-awareness of their dispositional characteristics and how their personalities affect their wellbeing at work, and; (2) encouraging management to facilitate practices where mental health workers feel connected, respected, and supported in their organisation.

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High contrast ratios between windows and surrounding surfaces could cause reduced visibility or discomfort for occupants. Consequently, building users may choose to intervene in lighting conditions through closing blinds and turning on the lamps in order to enhance indoor visual comfort. Such interventions increase projected electric lighting use in buildings. One simple method to prevent these problematic issues is increasing the luminance of the areas surrounding to the bright surface of windows through the use of energy-efficient supplementary lighting, such Light Emitting Diodes (LEDs). This paper reports on the results of a pilot study in conventional office in Brisbane, Australia. The outcomes of this study indicated that a supplementary LED system of approximately 18 W could reduce the luminance contrast on the window wall from values in the order of 117:1 to 33:1. In addition, the results of this experiment suggested that this supplementary strategy could increase the subjective scale appraisal of window appearance by approximately 33%, as well as reducing the likelihood of users’ intention to turn on the ceiling lights by about 27%. It could also diminish the likelihood of occupants’ intention to move the blind down by more than 90%.

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Purpose The present study aimed to review the effect of dehydration during Ramadan fasting on the health and ocular parameters leading to changes in eye function. Methods Articles included in the study were taken from PubMed, Ovid, Web of Science and Google Scholar up to 2014. Related articles were also obtained from scientific journals on fasting and vision system. Results Dehydration and nutrition changes in Ramadan cause an increase in tear osmolarity, ocular aberration, anterior chamber depth, IOL measurement, central corneal thickness, retinal and choroidal thicknesses, and also a decrease in IOP, tear secretion, and vitreous thickness. Conclusion Much research related to the effect of dehydration on ocular parameters during Ramadan fasting exists. The findings reveal association with significant changes on ocular parameters. Thus, it seems requisite to have a comprehensive study on "fasting and ocular parameters”, which will be helpful in making decisions and giving plan to the patients.

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At a campus in a low socioeconomic (SES) area, our University allows enrolled nurses entry into the second year of a Bachelor of Nursing, but attrition is high. Using the factors, described by Yorke and Thomas (2003) to have a positive impact on the attrition of low SES students, we developed strategies to prepare the enrolled nurses for the pharmacology and bioscience units of a nursing degree with the aim of reducing their attrition. As a strategy, the introduction of review lectures of anatomy, physiology and microbiology, was associated with significantly reduced attrition rates. The subsequent introduction of a formative website activity of some basic concepts in bioscience and pharmacology, and a workshop addressing study skills and online resources, were associated with a further reduction in attrition rates of enrolled nursing students in a Bachelor of Nursing.