424 resultados para heavy-quark effective theory


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Density functional theory (DFT) is a powerful approach to electronic structure calculations in extended systems, but suffers currently from inadequate incorporation of long-range dispersion, or Van der Waals (VdW) interactions. VdW-corrected DFT is tested for interactions involving molecular hydrogen, graphite, single-walled carbon nanotubes (SWCNTs), and SWCNT bundles. The energy correction, based on an empirical London dispersion term with a damping function at short range, allows a reasonable physisorption energy and equilibrium distance to be obtained for H2 on a model graphite surface. The VdW-corrected DFT calculation for an (8, 8) nanotube bundle reproduces accurately the experimental lattice constant. For H2 inside or outside an (8, 8) SWCNT, we find the binding energies are respectively higher and lower than that on a graphite surface, correctly predicting the well known curvature effect. We conclude that the VdW correction is a very effective method for implementing DFT calculations, allowing a reliable description of both short-range chemical bonding and long-range dispersive interactions. The method will find powerful applications in areas of SWCNT research where empirical potential functions either have not been developed, or do not capture the necessary range of both dispersion and bonding interactions.

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With the advent of alternative fuels, such as biodiesels and related blends, it is important to develop an understanding of their effects on inter-cycle variability which, in turn, influences engine performance as well as its emission. Using four methanol trans-esterified biomass fuels of differing carbon chain length and degree of unsaturation, this paper provides insight into the effect that alternative fuels have on inter-cycle variability. The experiments were conducted with a heavy-duty Cummins, turbo-charged, common-rail compression ignition engine. Combustion performance is reported in terms of the following key in-cylinder parameters: indicated mean effective pressure (IMEP), net heat release rate (NHRR), standard deviation of variability (StDev), coefficient of variation (CoV), peak pressure, peak pressure timing and maximum rate of pressure rise. A link is also established between the cyclic variability and oxygen ratio, which is a good indicator of stoichiometry. The results show that the fatty acid structures did not have a significant effect on injection timing, injection duration, injection pressure, StDev of IMEP, or the timing of peak motoring and combustion pressures. However, a significant effect was noted on the premixed and diffusion combustion proportions, combustion peak pressure and maximum rate of pressure rise. Additionally, the boost pressure, IMEP and combustion peak pressure were found to be directly correlated to the oxygen ratio. The emission of particles positively correlates with oxygen content in the fuel as well as in the air-fuel mixture resulting in a higher total number of particles per unit of mass.

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Research background For almost 80 years the Chuck Taylor (or Chuck T's) All Star basketball shoe has been an iconic item of fashion apparel. The Chuck T's were first designed in 1921 by Converse, an American shoe company and over the decades they became a popular item not purely for sports and athletic purposes but rather evolved into the shoe of choice for many subcultural groups as a fashion item. In some circles the Chuck Taylor is still seen as the "coolest" sneaker of all time - one which will never go out of fashion regardless of changing trends. With over 600 millions pairs sold all over the world since its release, the Converse shoe is representative of not only a fashion culture - but also of a consumption culture - that evolved as the driving force behind the massive growth of the Western economic system during the 20th Century. Artisan Gallery (Brisbane), in conjunction with the exhibition Reboot: Function, Fashion and the Sneaker, a history of the sneaker, selected 20 designers to customise and re-design the classic Converse Chuck Taylor All Stars shoe and in doing so highlighted the diversity of forms possible for creative outcomes. As Artisan Gallery Curator Kirsten Fitzpatrick states “We were expecting people to draw and paint on them. Instead, we had shoes... mounted as trophies.." referring to the presentation of "Converse Consumption". The exhibition ran from 21 June – 16 August 2012: Research question The Chuck T’s is one of many overwhelmingly commercially successful designs of the last century. Nowadays we are faced with the significant problems of overconsumption and the stress this causes on the natural ecosystem; and on people as a result. As an active member of the industrial design fraternity – a discipline that sits at the core of this problem - how can I use this opportunity to comment on the significant issue of consumption? An effective way to do this was to associate consumption of goods with consumption of sugar. There are significant similarities between our ceaseless desires to consume products and our fervent need to consume indulgent sweet foods. Artisan Statement Delicious, scrumptious, delectable... your pupils dilate, your blood pressure spikes, your liver goes into overdrive. Immediately, your brain cuts off the adenosine receptors, preventing drowsiness. Your body increases dopamine production, in-turn stimulating the pleasure receptors in your brain. Your body absorbs all the sweetness and turns it into fat – while all the nutrients that you actually require are starting to be destroyed, about to be expelled. And this is only after one bite! After some time though, your body comes crashing back to earth. You become irritable and begin to feel sluggish. Your eyelids seem heavy while your breathing pattern changes. Your body has consumed all the energy and destroyed all available nutrients. You literally begin to shut down. These are the physiological effects of sugar consumption. A perfect analogy for our modern day consumer driven world. Enjoy your dessert! Research contribution “Converse Consumption” contributes to the conversation regarding over-consumption by compelling people to reflect on their consumption behaviour through the reconceptualising of the deconstructed Chuck T’s in an attractive edible form. By doing so the viewer has to deal with the desire to consume the indulgent looking dessert with the contradictory fact that it is comprised of a pair of shoes. The fact that the shoes are Chuck T’s make the effect even more powerful due to their iconic status. These clashing motivations are what make “Converse Consumption” a bizarre yet memorable experience. Significance The exhibition was viewed by an excess of 1000 people and generated exceptional media coverage and public exposure/impact. As Artisan Gallery Curator Kirsten Fitzpatrick states “20 of Brisbane's best designers were given the opportunity to customise their own Converse Sneakers, with The Converse Blank Canvas Project.” And to be selected in this category demonstrates the calibre of importance for design prominence.

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Insulated Rail Joints (IRJs) are designed to electrically isolate two rails in rail tracks to control the signalling system for safer train operations. Unfortunately the gapped section of the IRJs is structurally weak and often fails prematurely especially in heavy haul tracks, which adversely affects service reliability and efficiency. The IRJs suffer from a number of failure modes; the railhead ratchetting at the gap is, however, regarded as the root cause and attended to in this thesis. Ratchetting increases with the increase in wheel loads; in the absence of a life prediction model, effective management of the IRJs for increased wagon wheel loads has become very challenging. Therefore, the main aim of this thesis is to determine method to predict IRJs' service life. The distinct discontinuity of the railhead at the gap makes the Hertzian theory and the rolling contact shakedown map, commonly used in the continuously welded rails, not applicable to examine the metal ratchetting of the IRJs. Finite Element (FE) technique is, therefore, used to explore the railhead metal ratchetting characteristics in this thesis, the boundary conditions of which has been determined from a full scale study of the IRJ specimens under rolling contact of the loaded wheels. A special purpose test set up containing full-scale wagon wheel was used to apply rolling wheel loads on the railhead edges of the test specimens. The state of the rail end face strains was determined using a non-contact digital imaging technique and used for calibrating the FE model. The basic material parameters for this FE model were obtained through independent uniaxial, monotonic tensile tests on specimens cut from the head hardened virgin rails. The monotonic tensile test data have been used to establish a cyclic load simulation model of the railhead steel specimen; the simulated cyclic load test has provided the necessary data for the three decomposed kinematic hardening plastic strain accumulation model of Chaboche. A performance based service life prediction algorithm for the IRJs was established using the plastic strain accumulation obtained from the Chaboche model. The predicted service lives of IRJs using this algorithm have agreed well with the published data. The finite element model has been used to carry out a sensitivity study on the effects of wheel diameter to the railhead metal plasticity. This study revealed that the depth of the plastic zone at the railhead edges is independent of the wheel diameter; however, large wheel diameter is shown to increase the IRJs' service life.

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Determining what consequences are likely to serve as effective punishment for any given behaviour is a complex task. This chapter focuses specifically on illegal road user behaviours and the mechanisms used to punish and deter them. Traffic law enforcement has traditionally used the threat and/or receipt of legal sanctions and penalties to deter illegal and risky behaviours. This process represents the use of positive punishment, one of the key behaviour modification mechanisms. Behaviour modification principles describe four types of reinforcers: positive and negative punishments and positive and negative reinforcements. The terms ‘positive’ and ‘negative’ are not used in an evaluative sense here. Rather, they represent the presence (positive) or absence (negative) of stimuli to promote behaviour change. Punishments aim to inhibit behaviour and reinforcements aim to encourage it. This chapter describes a variety of punishments and reinforcements that have been and could be used to modify illegal road user behaviours. In doing so, it draws on several theoretical perspectives that have defined behavioural reinforcement and punishment in different ways. Historically, the main theoretical approach used to deter risky road use has been classical deterrence theory which has focussed on the perceived certainty, severity and swiftness of penalties. Stafford and Warr (1993) extended the traditional deterrence principles to include the positive reinforcement concept of punishment avoidance. Evidence of the association between punishment avoidance experiences and behaviour has been established for a number of risky road user behaviours including drink driving, unlicensed driving, and speeding. We chose a novel way of assessing punishment avoidance by specifying two sub-constructs (detection evasion and punishment evasion). Another theorist, Akers, described the idea of competing reinforcers, termed differential reinforcement, within social learning theory (1977). Differential reinforcement describes a balance of reinforcements and punishments as influential on behaviour. This chapter describes comprehensive way of conceptualising a broad range of reinforcement and punishment concepts, consistent with Akers’ differential reinforcement concept, within a behaviour modification framework that incorporates deterrence principles. The efficacy of three theoretical perspectives to explain self-reported speeding among a sample of 833 Australian car drivers was examined. Results demonstrated that a broad range of variables predicted speeding including personal experiences of evading detection and punishment for speeding, intrinsic sensations, practical benefits expected from speeding, and an absence of punishing effects from being caught. Not surprisingly, being younger was also significantly related to more frequent speeding, although in a regression analysis, gender did not retain a significant influence once all punishment and reinforcement variables were entered. The implications for speed management, as well as road user behaviour modification more generally, are discussed in light of these findings. Overall, the findings reported in this chapter suggest that a more comprehensive approach is required to manage the behaviour of road users which does not rely solely on traditional legal penalties and sanctions.

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Organizations employ Enterprise Social Networks (ESNs) (e.g., Yammer) expecting better intra-organizational communication, effective knowledge sharing and, in general, greater collaboration. Despite their similarities with Public Social Networks (PSNs) (e.g., Twitter), ESNs are struggling to gain credence with employees. This paper is part of a larger research project that investigates mechanisms to enhance employees’ engagement in the ESNs. Through the lens of Control Theory, this paper reports preliminary findings of a pilot case study aimed to propose formal and informal mechanisms that impact employees’ intrinsic and extrinsic motivations to encourage their use of ESNs. The study results highlight (i) the need to better understand employees’ extrinsic and intrinsic motivations to use Social Networks, and (ii) that unlike a PSN which acts as a hedonic system, an ESN acts as a utilitarian system, highlighting the importance of supporting intrinsic motivations in its implementation.

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In the expanding literature on creative practice research, art and design are often described as a unified field. They are bracketed together (art-and-design), referred to as interchangeable terms (art/design), and nested together, as if the practices of one domain encompass the other. However it is possible to establish substantial differences in research approaches. In this chapter we argue that core distinctions arise out of the goals of the research, intentions invested in the resulting “artefacts” (creative works, products, events), and the knowledge claims made for the research outcomes. Moreover, these fundamental differences give rise to a number of contingent attributes of the research such as the forming contexts, methodological approaches, and ways of evidencing and reporting new knowledge. We do not strictly ascribe these differences to disciplinary contexts. Rather, we use the terms effective practice research and evocative practice research to describe the spirit of the two distinctive research paradigms we identify. In short, effective practice research (often pursued in design fields) seeks a solution (or resolution) to a problem identified with a particular community, and it produces an artefact that addresses this problem by effecting change (making a situation, product or process more efficient or effective in some way). On the other hand, evocative practice research (often pursued by creative arts fields) is driven by individual pre-occupations, cultural concerns or human experience more broadly. It produces artefacts that evoke affect and resonance, and are poetically irreducible in meaning. We cite recent examples of creative research projects that illustrate the distinctions we identify. We then go on to describe projects that integrate these modes of research. In this way, we map out a creative research spectrum, with distinct poles as well as multiple hybrid possibilities. The hybrid projects we reference are not presented as evidence an undifferentiated field. Instead, we argue that they integrate research modes in deliberate, purposeful and distinctive ways: employing effective practice research methods in the production of evocative artefacts or harnessing evocative (as well as effective) research paradigms to effect change.

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This thesis applied a grounded theory methodology to generate a theoretical understanding of the challenging and ambiguous dimensions of the contemporary role of the public-sector nurse educator within Australia. New knowledge provides a useful structure to examine nurse educator support and mechanisms to foster constructive workplace learning, collaborative relationships and effective contributions to better health care.

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Over the past decade, various paradigm shifts and challenges have rapidly changed learning and teaching in higher education including meeting student expectation for more engaging, more interactive learning experiences, the increased focus in the tertiary sector to deliver content online, and dealing with the complexities of fast-changing technologies. Rising to these challenges and responding to them is a complex and multi-faceted task. This paper discusses a case study undertaken applying a framework drawn from engineering education teaching and learning methods using the concept of academagogy, which is learner-centric, actively empowering students in building effective learning and engages facilitators in meaningful teaching and delivery methods.

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Dynamics is an essential core engineering subject and it is considered as one of the hardest subjects in the engineering discipline. Many students acknowledged that Dynamics is very hard to understand and comprehend the abstract concepts through traditional teaching methods with normal tutorials and assignments. In this study, we conducted an investigation on the application of visualization technique to help students learning the unit with the fundamental theory displayed in the physical space. The research was conducted based on the following five basic steps of Action Learning Cycle including: Identifying problem, Planning action, Implementing, Evaluating, and Reporting. Through our studies, we have concluded that visualization technique can definitely help students in learning and comprehending the abstract theories and concepts of Dynamics.

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The interest in utilising multiple heterogeneous Unmanned Aerial Vehicles (UAVs) in close proximity is growing rapidly. As such, many challenges are presented in the effective coordination and management of these UAVs; converting the current n-to-1 paradigm (n operators operating a single UAV) to the 1-to-n paradigm (one operator managing n UAVs). This paper introduces an Information Abstraction methodology used to produce the functional capability framework initially proposed by Chen et al. and its Level Of Detail (LOD) indexing scale. This framework was validated through comparing the operator workload and Situation Awareness (SA) of three experiment scenarios involving multiple autonomously heterogeneous UAVs. The first scenario was set in a high LOD configuration with highly abstracted UAV functional information; the second scenario was set in a mixed LOD configuration; and the final scenario was set in a low LOD configuration with maximal UAV functional information. Results show that there is a significant statistical decrease in operator workload when a UAV’s functional information is displayed at its physical form (low LOD - maximal information) when comparing to the mixed LOD configuration.

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Despite policies of deinstitutionalisation, many people with intellectual disabilities in developed western countries continue to live in mainstream institutional settings, such as correctional facilities, rather than in the community with support from disability services. This paper reports on the life stories of 10 people with intellectual disabilities, who had been imprisoned in adult correctional facilities in Queensland. The pathways taken by these 10 people into and out of prison are marked by significant abuse, neglect, and poverty. Significant disparity and disconnection is also displayed between the policies and service approaches, particularly between the disability, mental health, and correctional systems in Queensland. Based on these findings, a framework for practice, which spans both generic and specialist services, is suggested.

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INTRODUCTION: The shortage of nurses willing to work in rural Australian healthcare settings continues to worsen. Australian rural areas have a lower retention rate of nurses than metropolitan counterparts, with more remote communities experiencing an even higher turnover of nursing staff. When retention rates are lower, patient outcomes are known to be poorer. This article reports a study that sought to explore the reasons why registered nurses resign from rural hospitals in the state of New South Wales, Australia. METHODS: Using grounded theory methods, this study explored the reasons why registered nurses resigned from New South Wales rural hospitals. Data were collected from 12 participants using semi-structured interviews; each participant was a registered nurse who had resigned from a rural hospital. Nurses who had resigned due to retirement, relocation or maternity leave were excluded. Interviews were transcribed verbatim and imported into NVivo software. The constant comparative method of data collection and analysis was followed until a core category emerged. RESULTS: Nurses resigned from rural hospitals when their personal value of how nursing should occur conflicted with the hospital's organisational values driving the practice of nursing. These conflicting values led to a change in the degree of value alignment between the nurse and hospital. The degree of value alignment occurred in three dynamic stages that nurses moved through prior to resigning. The first stage, sharing values, was a time when a nurse and a hospital shared similar values. The second stage was conceding values where, due to perceived changes in a hospital's values, a nurse felt that patient care became compromised and this led to a divergence of values. The final stage was resigning, a stage where a nurse 'gave up' as they felt that their professional integrity was severely compromised. The findings revealed that when a nurse and organisational values were not aligned, conflict was created for a nurse about how they could perform nursing that aligned with their internalised professional values and integrity. Resignation occurred when nurses were unable to realign their personal values to changed organisational values - the organisational values changed due to rural area health service restructures, centralisation of budgets and resources, cumbersome hierarchies and management structures that inhibited communication and decision making, out-dated and ineffective operating systems, insufficient and inexperienced staff, bullying, and a lack of connectedness and shared vision. CONCLUSIONS: To fully comprehend rural nurse resignations, this study identified three stages that nurses move through prior to resignation. Effective retention strategies for the nursing workforce should address contributors to a decrease in value alignment and work towards encouraging the coalescence of nurses' and hospitals' values. It is imperative that strategies enable nurses to provide high quality patient care and promote a sense of connectedness and a shared vision between nurse and hospital. Senior managers need to have clear ways to articulate and imbue organisational values and be explicit in how these values accommodate nurses' values. Ward-level nurse managers have a significant responsibility to ensure that a hospital's values (both explicit and implicit) are incorporated into ward culture.

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This chapter will consider pedagogic change in Higher Education from the perspective of an Assistant Dean (Teaching and Learning) and one member of their leadership team with particular focus on reflective writing in their courses. The discussion will focus on leadership for the development of teaching capability for reflective writing development and implications for quality assurance of teaching and learning across faculties of a leading comprehensive University. The authors will present and contrast the experiences and challenges of developing teaching approaches for reflective writing across the discipline of teacher education. The chapter will argue a position for the establishment of a framework of distributed leadership that supports effective pedagogical change management generally and with specific reference to reflective writing.

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There is a general perception that public confidence in the insolvency profession is low as the result of the recent unethical practices of a few high profile liquidators. As a result, the effectiveness of the current regulatory mechanisms has been questioned, leading to a review of the performance of insolvency practitioners and subsequent regulation proposals. The challenge for the insolvency profession is balancing the expectations of the general public whilst ensuring that the obligations and duties imposed upon them are performed to acceptable and realistic standards. It is difficult (if not impossible) for the profession to meet this challenge in the absence of a cohesive framework which identifies those issues that require further regulation as opposed to those that relate to general education on the insolvency process. This paper will examine the audit expectations gap theory in the context of insolvency practitioners and suggests that a model based on this theory provides an effective framework for evaluating the regulation of the insolvency industry.