936 resultados para Exit ramp


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Current literature warns organisations about a global ageing phenomenon. Workplace ageing is causing a diminishing work pool which has consequences for a sustainable workforce in the future. This phenomenon continues to impact on local government councils in Australia. Australia has one of the world’s most rapidly ageing populations, and there is evidence that Australian local government councils are already resulting in an unsustainable workforce. Consequently, this research program investigated the role of older workers in the Queensland local government workplace in enabling them to extend their working lives towards transitional employment and a sustainable workforce in the future. Transitional Employment is intended as a strategy for enabling individuals to have greater control over their employment options and their employability during the period leading to their final exit from the workforce. There was no evidence of corporate support for older workers in Queensland local government councils other than tokenistic government campaigns encouraging organisations to "better value their older workers". (Queensland Government, 2007d, p.6). TE is investigated as a possible intervention for older workers in the future. The international and national literature review reflected a range of matters impacting on current older workers in the workforce and barriers preventing them from accessing services towards extending their employment beyond the traditional retirement age (60 years) as defined by the Australian Government; an age when individuals can access their superannuation. Learning and development services were identified as one of those barriers. There was little evidence of investment in or consistent approaches to supporting older workers by organisations. Learning and development services appeared at best to be ad hoc, reactive to corporate productivity and outputs with little recognition of the ageing phenomenon (OECD, 2006, p.23) and looming skills and labour shortages (ALGA, 2006, p. 19). Themes from the literature review led to the establishment of three key research questions: 1. What are the current local government workforce issues impacting on skills and labour retention? 2. What are perceptions about the current workplace environment? And, 3. What are the expectations about learning and development towards extending employability of older workers within the local government sector? The research questions were explored by utilising three qualitative empirical studies, using some numerical data for reporting and comparative analysis. Empirical Study One investigated common themes for accessing transitional employment and comprised two phases. A literature review and Study One data analysis enabled the construction of an initial Transitional Employment Model which includes most frequent themes. Empirical Study Two comprised focus groups to further consider those themes. This led to identification of issues impacting the most on access to learning and development by older workers and towards a revised TEM. Findings presented majority support for transitional employment as a strategy for supporting older workers to work beyond their traditional retirement age. Those findings are presented as significant issues impacting on access to transitional employment within the final 3-dimensionsal TEM. The model is intended as a guide for responding to an ageing workforce by local government councils in the future. This study argued for increased and improved corporate support, particularly for learning and development services for older workers. Such support will enable older workers to maintain their employability and extend their working lives; a sustainable workforce in the future.

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Pressure feeder chutes are pieces of equipment used in sugar cane crushing to increase the amount of cane that can be put through a mill. The continuous pressure feeder was developed with the objective to provide a constant feed of bagasse under pressure to the mouth of the crushing mills. The pressure feeder chute is used in a sugarcane milling unit to transfer bagasse from one set of crushing rolls to a second set of crushing rolls. There have been many pressure feeder chute failures in the past. The pressure feeder chute is quite vulnerable and if the bagasse throughput is blocked at the mill rollers, the pressure build-up in the chute can be enormous, which can ultimately result in failure. The result is substantial damage to the rollers, mill and chute construction, and downtimes of up to 48 hours can be experienced. Part of the problem is that the bagasse behaviour in the pressure feeder chute is not understood well. If the pressure feeder chute behaviour was understood, then the chute geometry design could be modified in order to minimise risk of failure. There are possible avenues for changing pressure feeder chute design and operations with a view to producing more reliable pressure feeder chutes in the future. There have been previous attempts to conduct experimental work to determine the causes of pressure feeder chute failures. There are certain guidelines available, however pressure feeder chute failures continue. Pressure feeder chute behaviour still remains poorly understood. This thesis contains the work carried out between April 14th 2009 and October 10th 2012 that focuses on the design of an experimental apparatus to measure forces and visually observe bagasse behaviour in an attempt to understand bagasse behaviour in pressure feeder chutes and minimise the risk of failure.

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Introduction: The accurate identification of tissue electron densities is of great importance for Monte Carlo (MC) dose calculations. When converting patient CT data into a voxelised format suitable for MC simulations, however, it is common to simplify the assignment of electron densities so that the complex tissues existing in the human body are categorized into a few basic types. This study examines the effects that the assignment of tissue types and the calculation of densities can have on the results of MC simulations, for the particular case of a Siemen’s Sensation 4 CT scanner located in a radiotherapy centre where QA measurements are routinely made using 11 tissue types (plus air). Methods: DOSXYZnrc phantoms are generated from CT data, using the CTCREATE user code, with the relationship between Hounsfield units (HU) and density determined via linear interpolation between a series of specified points on the ‘CT-density ramp’ (see Figure 1(a)). Tissue types are assigned according to HU ranges. Each voxel in the DOSXYZnrc phantom therefore has an electron density (electrons/cm3) defined by the product of the mass density (from the HU conversion) and the intrinsic electron density (electrons /gram) (from the material assignment), in that voxel. In this study, we consider the problems of density conversion and material identification separately: the CT-density ramp is simplified by decreasing the number of points which define it from 12 down to 8, 3 and 2; and the material-type-assignment is varied by defining the materials which comprise our test phantom (a Supertech head) as two tissues and bone, two plastics and bone, water only and (as an extreme case) lead only. The effect of these parameters on radiological thickness maps derived from simulated portal images is investigated. Results & Discussion: Increasing the degree of simplification of the CT-density ramp results in an increasing effect on the resulting radiological thickness calculated for the Supertech head phantom. For instance, defining the CT-density ramp using 8 points, instead of 12, results in a maximum radiological thickness change of 0.2 cm, whereas defining the CT-density ramp using only 2 points results in a maximum radiological thickness change of 11.2 cm. Changing the definition of the materials comprising the phantom between water and plastic and tissue results in millimetre-scale changes to the resulting radiological thickness. When the entire phantom is defined as lead, this alteration changes the calculated radiological thickness by a maximum of 9.7 cm. Evidently, the simplification of the CT-density ramp has a greater effect on the resulting radiological thickness map than does the alteration of the assignment of tissue types. Conclusions: It is possible to alter the definitions of the tissue types comprising the phantom (or patient) without substantially altering the results of simulated portal images. However, these images are very sensitive to the accurate identification of the HU-density relationship. When converting data from a patient’s CT into a MC simulation phantom, therefore, all possible care should be taken to accurately reproduce the conversion between HU and mass density, for the specific CT scanner used. Acknowledgements: This work is funded by the NHMRC, through a project grant, and supported by the Queensland University of Technology (QUT) and the Royal Brisbane and Women's Hospital (RBWH), Brisbane, Australia. The authors are grateful to the staff of the RBWH, especially Darren Cassidy, for assistance in obtaining the phantom CT data used in this study. The authors also wish to thank Cathy Hargrave, of QUT, for assistance in formatting the CT data, using the Pinnacle TPS. Computational resources and services used in this work were provided by the HPC and Research Support Group, QUT, Brisbane, Australia.

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This paper examines the outcomes of nascent and young entrepreneurial firms in Australia. Findings of interest in this paper include: • After three years similar proportions of nascent firms reach an operational state (31 per cent), i.e. sales regularly exceed costs, compared with those that have terminated (35 per cent), and those who are still trying to achieve venture creation (34 per cent). This outcome closely mirrors the outcomes in the US PSED study. • The young firm sample shows that these new ventures remain more robust to firm closure. The vast majority of young firms (78 per cent) continue to be active in the market the last time they participated in CAUSEE. • The annual termination rate for young firms is 9 per cent at most, and 14 per cent cumulatively, while cumulatively only 8 per cent of young firms experience a drop-off in activity to be considered as having uncertain status. • The average number of employees in Nascent Firms is one person, the average number of Young Firm employees increases from two at first sampling to three after three years. • While the founders of exiting Nascent Firms are more likely to return to their old job upon termination of their business, Young Firm founders move on to new jobs. Regardless the majority of exiting firm founders rate their experience as positive and are prepared to attempt business creation in the future.

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This paper seeks to uncover the factors that lead to a successful entrepreneurial experience and or venture. Findings of interest in this paper include: • A venture’s initial aspirations are a double edged sword. Ambition may lead to improved performance by striving to reach harder goals. Harder goals are more difficult therefore this may lead to some dissatisfaction, and possibly abandonment of the venture. • Venture legitimacy is important to establish where possible. Firms that formalize their legal form are more successful, as are those set up a shop-front in order to makes sales. • Increased use of technology and higher levels of novelty does not guarantee success early on. Firms of this nature have longer processes, and attempting to create brand new markets is difficult to achieve. At the same time developing your own technology and securing this intellectual property is important for success. • Having goals to work towards and business planning may be useful, but only if the plan is actively revised. Just having a business plan does not matter. Business plans are more useful as a thinking tool than as a blueprint for action. It is the process of thinking through while reviewing the plan that provides the benefit, not following its instruction to the letter.

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Bi-2212 tapes were fabricated using a powder-in-tube method and their superconducting properties were measured as a function of heat treatment. The tapes were heated to temperature, T1 (884-915 °C), and kept at that temperature for 20 min to induce partial (incongruent) melting. The samples were cooled to T2 with a ramp rate of 120 °C h-1 and then slowly cooled to T3 with a cooling rate, R2, and from T3 to T4 with a cooling rate, R3. The tapes were kept at the temperature T4 for P1 hours and then cooled to room temperature. Both R1 and R2 were chosen between 2 and 8 °C h-1. It was found that the structure and Jc of the tapes depend on the sintering conditions, i.e. T1-4, R1-3 and P1. The highest Jc of 5800 Å cm-2 was obtained at 77 K in a self-field with heat treatment where T1 = 894 and 899 °C, R1 = R2 = 5 °C h-1 and P1 = 6 h were employed. When 0.7% of bend strain, which is equivalent to a bend radius of 5 mm, was applied to the tape, 80% of the initial Jc was sustained.

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Numerical simulations of thermomagnetic convection of paramagnetic fluids placed in a micro-gravity condition (g ≈ 0) and under a uniform vertical gradient magnetic field in an open ended square enclosure with ramp heating temperature condition applied on a vertical wall is investigated in this study. In presence of the strong magnetic gradient field thermal convection of the paramagnetic fluid might take place even in a zero-gravity environment as a direct consequence of temperature differences occurring within the fluid. The thermal boundary layer develops adjacent to the hot wall as soon as the ramp temperature condition is applied on it. There are two scenarios can be observed based on the ramp heating time. The steady state of the thermal boundary layer can be reached before the ramp time is finished or vice versa. If the ramp time is larger than the quasi-steady time then the thermal boundary layer is in a quasi-steady mode with convection balancing conduction after the quasi-steady time. Further increase of the heat input simply accelerates the flow to maintain the proper thermal balance. Finally, the boundary layer becomes completely steady state when the ramp time is finished. Effects of magnetic Rayleigh number, Prandtl number and paramagnetic fluid parameter on the flow pattern and heat transfer are presented.

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Victim/survivors of human trafficking involving partner migration employ diverse help-seeking strategies, both formal and informal, to exit their exploitative situations. Drawing on primary research conducted by Lyneham and Richards (forthcoming), the authors highlight the importance of educating the community and professionals from a wide range of sectors—including health, mental health, child protection, social welfare, social work, domestic violence, migration, legal and law enforcement services—about human trafficking and the help-seeking strategies of victims/survivors in order to support them to leave exploitative situations. Enhancing Australia’s knowledge of victim/survivors’ help-seeking strategies will better inform government and community responses to this crime, improve detection and identification of human trafficking matters and subsequent referral to appropriate victim services.

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A BPMN model is well-structured if splits and joins are always paired into single-entry-single-exit blocks. Well-structuredness is often a desirable property as it promotes readability and makes models easier to analyze. However, many process models found in practice are not well-structured, and it is not always feasible or even desirable to restrict process modelers to produce only well-structured models. Also, not all processes can be captured as well-structured process models. An alternative to forcing modelers to produce well-structured models, is to automatically transform unstructured models into well-structured ones when needed and possible. This talk reviews existing results on automatic transformation of unstructured process models into structured ones.

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This paper addresses the problem of computing the aggregate QoS of a composite service given the QoS of the services participating in the composition. Previous solutions to this problem are restricted to composite services with well-structured orchestration models. Yet, in existing languages such as WS-BPEL and BPMN, orchestration models may be unstructured. This paper lifts this limitation by providing equations to compute the aggregate QoS for general types of irreducible unstructured regions in orchestration models. In conjunction with existing algorithms for decomposing business process models into single-entry-single-exit regions, these functions allow us to cover a larger set of orchestration models than existing QoS aggregation techniques.

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Numerical simulations of thermomagnetic convection of paramagnetic fluids placed in a micro-gravity condition (g nearly 0) and under a uniform vertical gradient magnetic field in an open ended square enclosure with ramp heating temperature condition applied on a vertical wall is investigated in this study. In presence of the strong magnetic gradient field thermal convection of the paramagnetic fluid might take place even in a zero-gravity environment as a direct consequence of temperature differences occurring within the fluid. The thermal boundary layer develops adjacent to the hot wall as soon as the ramp temperature condition is applied on it. There are two scenario that can be observed based on the ramp heating time. The steady state of the thermal boundary layer can be reached before the ramp time is finished or vice versa. If the ramp time is larger than the quasi-steady time then the thermal boundary layer is in a quasi-steady mode with convection balancing conduction after the quasi-steady time. Further increase of the heat input simply accelerates the flow to maintain the proper thermal balance. Finally, the boundary layer becomes completely steady state when the ramp time is finished. Effects of magnetic Rayleigh number, Prandtl number and paramagnetic fluid parameter on the flow pattern and heat transfer are presented.

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Cumulative arrays have played an important role in the early development of the secret sharing theory. They have not been subject to extensive study so far, as the secret sharing schemes built on them generally result in much larger sizes of shares, when compared with other conventional approaches. Recent works in threshold cryptography show that cumulative arrays may be the appropriate building blocks in non-homomorphic threshold cryptosystems where the conventional secret sharing methods are generally of no use. In this paper we study several extensions of cumulative arrays and show that some of these extensions significantly improve the performance of conventional cumulative arrays. In particular, we derive bounds on generalised cumulative arrays and show that the constructions based on perfect hash families are asymptotically optimal. We also introduce the concept of ramp perfect hash families as a generalisation of perfect hash families for the study of ramp secret sharing schemes and ramp cumulative arrays.

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The effect of a magnetic field of two magnetic coils on the ion current density distribution in the setup for low-temperature plasma deposition is investigated. The substrate of 400 mm diameter is placed at a distance of 325 mm from the plasma duct exit, with the two magnetic coils mounted symmetrically under the substrate at a distance of 140 mm relative to the substrate centre. A planar probe is used to measure the ion current density distribution along the plasma flux cross-sections at distances of 150, 230, and 325 mm from the plasma duct exit. It is shown that the magnetic field strongly affects the ion current density distribution. Transparent plastic films are used to investigate qualitatively the ion density distribution profiles and the effect of the magnetic field. A theoretical model is developed to describe the interaction of the ion fluxes with the negative space charge regions associated with the magnetic trapping of the plasmaelectrons. Theoretical results are compared with the experimental measurements, and a reasonable agreement is demonstrated.

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This thesis presents four essays in the political economy of elections and reforms. The first study exploits discontinuities around school entry cut-off dates to show that early childhood conditions can impact the probability to become a top-flight politician. The second study provides empirical estimates of the effect of sequential voting on turnout and bandwagon voting outside the laboratory. The third work describes a novel nonparametric strategy to identify tactical voting patterns directly from balloting results using British election data. Finally, a study is put forward that examines the political feasibility of reforms.

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Weaving sections, a common design of motorways, require extensive lane-change manoeuvres. Numerous studies have found that drivers tend to make their lane changes as soon as they enter the weaving section, as the traffic volume increases. Congestion builds up as a result of this high lane-changing concentration. Importantly, such congestion also limits the use of existing infrastructure, the weaving section downstream. This behaviour thus affects both safety and operational aspects. The potential tool for managing motorways effectively and efficiently is cooperative intelligent transport systems (C-ITS). This research investigates a lane-change distribution advisory application based on C-ITS for weaving vehicles in weaving sections. The objective of this research is to alleviate the lane-changing concentration problem by coordinating weaving vehicles to ensure that such lane-changing activities are evenly distributed over the existing weaving length. This is achieved by sending individual messages to drivers based on their location to advise them when to start their lane change. The research applied a microscopic simulation in AIMSUN to evaluate the proposed strategy’s effectiveness in a one-sided ramp weave. The proposed strategy was evaluated using different weaving advisory proportions, traffic demands and penetration rates. The evaluation revealed that the proposed lane-changing advisory has the potential to significantly improve delay.