606 resultados para Hold-up problem


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This paper examines the Australian breakfast news program Sunrise. By drawing on interviews with both viewers and producers, as well as selected textual analysis, it examines the show, how it is "used" as a news source, and explores its role within the audience’s morning routines. By viewing the show as a part of what Baym has termed the "Televisual Sphere", it will argue against the common discourse that the program has simply followed a populist style in pursuit of higher ratings. Because of its success in communicating and connecting with viewers, it may be more constructive to consider Sunrise a very effective form of journalism which has been at the forefront of the recent trend towards increased levels of viewer input in television journalism.

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In photovoltaic, fuel cells and storage batteries, the low output DC voltage should be boosted. Therefore, a step-up converter is necessary to boost the low DC voltage for the DC link voltage of the inverter. The main contribution of this chapter is to electrical energy conversion in renewable energy systems based on multilevel inverters. Different configuration of renewable energy systems based on power converters will be discussed in detail. Finally, a new single inductor Multi-Output Boost (MOB) converter is proposed, which is compatible with the diode-clamped configuration. Steady state and dynamic analyses have been carried out in order to show the validity of the proposed topology. Then the joint circuit of the proposed DC-DC converter with a three-level diode-clamped converter is presented in order to have a series regulated voltage at the DC link voltage of the diode-clamped inverter. MOB converter can boost the low input DC voltage of the renewable energy sources and at the same time adjust the voltage across each capacitor to the desired voltage levels, thereby solving the main problem associated with capacitor voltage imbalance in this type of multilevel converter.

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Problem-based learning (PBL) is a pedagogical methodology that presents the learner with a problem to be solved to stimulate and situate learning. This paper presents key characteristics of a problem-based learning environment that determines its suitability as a data source for workrelated research studies. To date, little has been written about the availability and validity of PBL environments as a data source and its suitability for work-related research. We describe problembased learning and use a research project case study to illustrate the challenges associated with industry work samples. We then describe the PBL course used in our research case study and use this example to illustrate the key attributes of problem-based learning environments and show how the chosen PBL environment met the work-related research requirements of the research case study. We propose that the more realistic the PBL work context and work group composition, the better the PBL environment as a data source for a work-related research. The work context is more realistic when relevant and complex project-based problems are tackled in industry-like work conditions over longer time frames. Work group composition is more realistic when participants with industry-level education and experience enact specialized roles in different disciplines within a professional community.

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This thesis describes outcomes of a research study conducted to investigate the nutrient build-up and wash-off processes on urban impervious surfaces. The data needed for the study was generated through a series of field investigations and laboratory test procedures. The study sites were selected in urbanised catchments to represent typical characteristics of residential, industrial and commercial land uses. The build-up and wash-off samples were collected from road surfaces in the selected study sites. A specially designed vacuum collection system and a rainfall simulator were used for sample collection. According to the data analysis, the solids build-up on road surfaces was significantly finer with more than 80% of the particles below 150 ìm for all the land uses. Nutrients were mostly associated with the particle size range below 150 ìm in both build-up and wash-off samples irrespective of type of land use. Therefore, the finer fraction of solids was the most important for the nutrient build-up and particulate nutrient wash-off processes. Consequently, the design of stormwater quality mitigation measures should target particles less than 150 ìm for the removal of nutrients irrespective of type of land use. Total kjeldahl nitrogen (TKN) was the most dominant form of nitrogen species in build-up on road surfaces. Phosphorus build-up on road surfaces was mainly in inorganic form and phosphate (PO4 3-) was the most dominant form. The nutrient wash-off process was found to be dependent on rainfall intensity and duration. Concentration of both total nitrogen and phosphorus was higher at the beginning of the rain event and decreased with the increase in rainfall duration. Consequently, in the design of stormwater quality mitigation strategies for nutrients removal, it is important to target the initial period of rain events. The variability of wash-off of nitrogen with rainfall intensity was significantly different to phosphorus wash-off. The concentration of nitrogen was higher in the wash-off for low intensity rain events compared to the wash-off for high intensity rain events. On the other hand, the concentration of phosphorus in the wash-off was high for high intensity rain events compared to low intensity rain events. Consequently, the nitrogen washoff can be defined as a source limiting process and phosphorus wash-off as a transport limiting process. This highlights the importance of taking into consideration the wash-off of low intensity rain events in the design of stormwater quality mitigation strategies targeting the nitrogen removal. All the nitrogen species in wash-off are primarily in dissolved form whereas phosphorus is in particulate form. The differences in the nitrogen and phosphorus wash-off processes is principally due to the degree of solubility, attachment to particulates, composition of total nitrogen and total phosphorus and the degree of adherence of the solids particles to the surface to which nutrients are attached. The particulate nitrogen available for wash-off is removed readily as these are mobilised as free solids particles on the surface. Phosphorus is washed-off mostly with the solids particles which are strongly adhered to the surface or as the fixed solids load. Investigation of the nitrogen wash-off process using bulk wash-off samples was in close agreement with the investigation of dissolved fraction of wash-off solids. This was primarily due to the predominant nature of dissolved nitrogen. However, the investigation of the processes which underpin phosphorus wash-off using bulk washoff samples could lead to loss of information. This is due to the composition of total phosphorus in wash-off solids and the inherent variability of the wash-off process for the different particle size ranges. This variability should preferably be taken into consideration as phosphorus wash-off is predominantly in particulate form. Therefore, care needs to be taken in the investigation of the phosphorus wash-off process using bulk wash-off samples to ensure that there is no loss of information and hence result in misleading outcomes. The investigation of different particle size ranges of wash-off solids is preferable in the interest of designing effective stormwater quality management strategies targeting phosphorus removal.

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Maximisation of Knowledge-Based Development (KBD) benefits requires effective dissemination and utilisation mechanisms to accompany the initial knowledge creation process. This work highlights the potential for interactions between Supply Chains (SCs) and Small and Medium sized Enterprise Clusters (SMECs), (including via ‘junction’ firms which are members of both networks), to facilitate such effective dissemination and utilisation of knowledge. In both these network types there are firms that readily utilise their relationships and ties for ongoing business success through innovation. The following chapter highlights the potential for such beneficial interactions between SCs and SMECs in key elements of KBD, particularly knowledge management, innovation and technology transfer. Because there has been little focus on the interactions between SCs and SMECs, particularly when firms simultaneously belong to both, this chapter examines the conduits through which information and knowledge can be transferred and utilised. It shows that each network type has its own distinct advantages in the types of information searched for and transferred amongst network member firms. Comparing and contrasting these advantages shows opportunities for both networks to leverage the knowledge sharing strengths of each other, through these ‘junctions’ to address their own weaknesses, allowing implications to be drawn concerning new ways of utilising relationships for mutual network gains.

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Mathematical problem solving has been the subject of substantial and often controversial research for several decades. We use the term, problem solving, here in a broad sense to cover a range of activities that challenge and extend one’s thinking. In this chapter, we initially present a sketch of past decades of research on mathematical problem solving and its impact on the mathematics curriculum. We then consider some of the factors that have limited previous research on problem solving. In the remainder of the chapter we address some ways in which we might advance the fields of problem-solving research and curriculum development.

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This study reported on the issues surrounding the acquisition of problem-solving competence of middle-year students who had been ascertained as above average in intelligence, but underachieving in problem-solving competence. In particular, it looked at the possible links between problem-posing skills development and improvements in problem-solving competence. A cohort of Year 7 students at a private, non-denominational, co-educational school was chosen as participants for the study, as they undertook a series of problem-posing sessions each week throughout a school term. The lessons were facilitated by the researcher in the students’ school setting. Two criteria were chosen to identify participants for this study. Firstly, each participant scored above the 60th percentile in the standardized Middle Years Ability Test (MYAT) (Australian Council for Educational Research, 2005) and secondly, the participants all scored below the cohort average for Criterion B (Problem-solving Criterion) in their school mathematics tests during the first semester of Year 7. Two mutually exclusive groups of participants were investigated with one constituting the Comparison Group and the other constituting the Intervention Group. The Comparison Group was chosen from a Year 7 cohort for whom no problem-posing intervention had occurred, while the Intervention Group was chosen from the Year 7 cohort of the following year. This second group received the problem-posing intervention in the form of a teaching experiment. That is, the Comparison Group were only pre-tested and post-tested, while the Intervention Group was involved in the teaching experiment and received the pre-testing and post-testing at the same time of the year, but in the following year, when the Comparison Group have moved on to the secondary part of the school. The groups were chosen from consecutive Year 7 cohorts to avoid cross-contamination of the data. A constructionist framework was adopted for this study that allowed the researcher to gain an “authentic understanding” of the changes that occurred in the development of problem-solving competence of the participants in the context of a classroom setting (Richardson, 1999). Qualitative and quantitative data were collected through a combination of methods including researcher observation and journal writing, video taping, student workbooks, informal student interviews, student surveys, and pre-testing and post-testing. This combination of methods was required to increase the validity of the study’s findings through triangulation of the data. The study findings showed that participation in problem-posing activities can facilitate the re-engagement of disengaged, middle-year mathematics students. In addition, participation in these activities can result in improved problem-solving competence and associated developmental learning changes. Some of the changes that were evident as a result of this study included improvements in self-regulation, increased integration of prior knowledge with new knowledge and increased and contextualised socialisation.

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We evaluated sustainability of an intervention to reduce women’s cardiovascular risk factors, determined the influence of self-efficacy, and described women’s current health. We used a mixed method approach that utilized forced choice and open-ended questionnaire items about health status, habits, and self-efficacy. Sixty women, average age 61, returned questionnaires. Women in the original intervention group continued health behaviors intended to reduce cardiovascular disease (CVD) at a higher rate than the control group, supporting the feasibility of a targeted intervention built around women’s individual goals. The role of self-efficacy in behavior change is unclear. The original intervention group reported higher self-reported health.

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In the paper, the flow-shop scheduling problem with parallel machines at each stage (machine center) is studied. For each job its release and due date as well as a processing time for its each operation are given. The scheduling criterion consists of three parts: the total weighted earliness, the total weighted tardiness and the total weighted waiting time. The criterion takes into account the costs of storing semi-manufactured products in the course of production and ready-made products as well as penalties for not meeting the deadlines stated in the conditions of the contract with customer. To solve the problem, three constructive algorithms and three metaheuristics (based one Tabu Search and Simulated Annealing techniques) are developed and experimentally analyzed. All the proposed algorithms operate on the notion of so-called operation processing order, i.e. the order of operations on each machine. We show that the problem of schedule construction on the base of a given operation processing order can be reduced to the linear programming task. We also propose some approximation algorithm for schedule construction and show the conditions of its optimality.

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Interdisciplinary studies are fundamental to the signature practices for the middle years of schooling. Middle years researchers claim that interdisciplinarity in teaching appropriately meets the needs of early adolescents by tying concepts together, providing frameworks for the relevance of knowledge, and demonstrating the linking of disparate information for solution of novel problems. Cognitive research is not wholeheartedly supportive of this position. Learning theorists assert that application of knowledge in novel situations for the solution of problems is actually dependent on deep discipline based understandings. The present research contrasts the capabilities of early adolescent students from discipline based and interdisciplinary based curriculum schooling contexts to successfully solve multifaceted real world problems. This will inform the development of effective management of middle years of schooling curriculum.

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The homeless have been subject to considerable scrutiny, historically and within current social, political and public discourse. The aetiology of homelessness has been the focus of a large body of economic, sociological, historical and political investigation. Importantly, efforts to conceptualise, explain and measure, the phenomenon of homelessness and homeless people has occurred largely within the context of defining “the problem of the homeless” and the generation of solutions to the ‘problem’. There has been little consideration of how and why homelessness has come to be seen, or understood, as a problem, or how this can change across time and/or place. This alternative stream of research has focused on tracing and analysing the relationship between how people experiencing homeless have become a matter of government concern and the manner in which homelessness itself has been problematised. With this in mind this study has analysed the discourses - political, social and economic rationalities and knowledges - which have provided the conditions of possibility for the identification of the homeless and homelessness as a problem needing to be governed and the means for translating these discourses into the applied domain. The aim of this thesis has been to contribute to current knowledge by developing a genealogy of the conditions and rationalities that have underpinned the problematisation of homelessness and the homeless. The outcome of this analysis has been to open up the opportunity to consider alternative governmental possibilities arising from the exposure of the way in which contemporary problematisation and responses have been influenced by the past. An understanding of this process creates an ability to appreciate the intended and unintended consequences for the future direction of public policy and contemporary research.

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The paper describes the implementation of a project within Australian Catholic University designed to launch the Faculties into online education in a manner which ensured quality in all aspects of the teaching-learning experiences of academics and students. Key elements of the strategic approach adopted by the project leaders, including the involvement of a specialist commercial provider of web-based delivery systems as a partner in the project, mechanisms to support the initiative through the first stages, careful choice of the programs offered online, and staff development matched to the emerging needs of those involved in the teaching of courses, are described. Challenges encountered in the implementation process, and the factors which assisted in overcoming these problems are identified. The paper draws upon this experience to raise some important issues relevant to the successful introduction of online education as an integral component of the teaching repertoire of Faculties.