1,523 results for ResearchSpace@Auckland, 2013

  • The impact of cell ventilation on the top heat losses and fugitive emissions in an aluminium smelting cell

    Abbas, H; Taylor, Mark; Farid, Mohammed; Chen, John (2013-04-08)

    Book item
    The University of Auckland Library

    Problems associated with aluminium smelting cell ventilation, caused by leakage of fume gases through pots superstructure gaps into the potroom, are normally solved by increasing the fume suction rate (draught) above certain levels. It is also known that, fugitive emissions are associated with reducing the draught below certain critical levels. Top heat losses are increasing in smelting cells as line amperage is raised. This drives further fugitive emissions through greater buoyancy of the fume/air mixture. A quantitative understanding of the relationship between fugitive emissions, superstructure tightness, top heat loss, and cell draught is crucial in the environmental context. It is also important if this top heat loss could be recovered for re-use. This problem is studied here computationally using the ANSYS-CFX software. Possibilities to improve cell ventilation and to decrease fugitive emissions are analysed for a typical industrial cell. The computed cell emissions and temperatures are compared with measured values. The impact of draught on ventilation and heat loss is also discussed

    View record details
  • A water-model study of the ledge heat transfer in an aluminium cell

    Chen, John; Wei, CC; Ackland, AD (2013-04-08)

    Book item
    The University of Auckland Library

    A heat transfer probe was developed for studying the ledge heat transfer in a full-scale 3-D air-water model. Quantitative measurements were conducted to determine the bath/ledge heat transfer characteristics at various positions and different operating conditions. A similitude analysis was carried out to relate the measured point results to data available in the literature. A suggested range of heat transfer coefficients for the reduction cell is presented. Variation of the heat transfer were examined as a function of the anode bottom inclination, the position on the side ledge relative to the anode slot, and positions in the vertical direction. ?? 2013 The Minerals, Metals & Materials Society.

    View record details
  • Design considerations for selecting the number of point feeders in modern reduction cells

    Walker, ML; Purdie, JM; Wai-Poi, NS; Welch, BJ; Chen, John (2013-04-08)

    Book item
    The University of Auckland Library

    Point feeding systems are now installed in most modern reduction cells in preference to bar breakers. The main reason for this choice is that point feeders allow improved alumina dissolution. However complete alumina dissolution is not an explicit design criterion for selecting the size of the alumina dump or the number of feeders required. In this paper, three performance criteria for determining the number of point feeders required in a cell are investigated. These are: acceptable alumina dissolution, satisfactory mixing to avoid concentration gradients and a satisfactory rate of alumina concentration increase after anode effect. Using a combination of laboratory data and measurements from industrial cells, it is shown that the alumina dissolution requirement is likely to be the most difficult to satisfy. Complete alumina dissolution upon addition is unlikely to be achieved with the point feeder designs installed in most modern cells. ?? 2013 The Minerals, Metals & Materials Society. Published 2013 by John Wiley & Sons, Inc.

    View record details
  • The interaction between current efficiency and energy balance in aluminium reduction cells

    Stevens, FJ; Zhang, W; Taylor, Mark; Chen, John (2013-04-08)

    Book item
    The University of Auckland Library

    In aluminium reduction cells the current efficiency interacts with the energy balance through both the thermodynamics and the hydrodynamics of the reduction process. The overall enthalpy for the reduction reaction is endothermic and increases with current efficiency due to lower heat evolution from the re-oxidation reaction. Changes in current efficiency due to changed mass transfer conditions will lead to an energy deficit or surplus. This will occur predominantly in the electrolyte channels where the largest proportion of mass transfer-driven current efficiency loss occurs. Other sources of current efficiency loss such as electronic loss of faradaic current will further reduce the endothermic contribution of the reaction enthalpy and may cause localised energy surpluses. The energy balance directly affects the electrolyte temperature and composition. It also affects the volume of the liquid electrolyte and the shape and thickness of side freeze and crust, which determine the shape of the operating cavity. Bath composition and temperature determine the physical properties of the electrolyte which, along with the geometry of the flow cavity, influence the turbulence of the bubble-driven circulation and the disturbance to the electrolyte-metal interface. Both factors influence the mass transfer and hence, metal reoxidation rate. ?? 2013 The Minerals, Metals & Materials Society.

    View record details
  • Operational and control improvements in reduction lines at Aluminium Delfzijl

    Stam, MA; Taylor, Mark; Chen, John; Van Dellen, S (2013-04-08)

    Book item
    The University of Auckland Library

    Nowadays viability of smelters requires operation of cells at or beyond known performance limits. At Aldel over the last ten years the intensity of electrical energy dissipation and alumina dissolution per cubic centimeter of liquid bath have increased by 50% as production (+40%) and specific energy consumption (-6%) have improved. The cell imbalances resulting from this increased intensity must be sensed quickly and their causes corrected or removed to maintain the cells in their most efficient operating zone. This defines a new control objective for smelting relating to diagnosis of causes of abnormality in strongly interactive multivariate processes. Timely identification of these causes of variation is linked to operational practice improvement and better control decisions in reduction lines. This paper describes smelter based improvement of operational practices and control decisions using the above objective. Statistical multivariate control surfaces are presented for operating cells and identified abnormal behaviours are discussed. ?? 2013 The Minerals, Metals & Materials Society.

    View record details
  • Mixed pedagogic modalities: The potential for increased student engagement and success

    McPhail, Graham (2013)

    Journal article
    The University of Auckland Library

    This paper utilises the three theoretical scenarios or ???educational futures??? developed by Michael Young and Johan Muller as reference points for discussing the curriculum conception approaches observed in a recent doctoral study in music education. In using Young and Muller???s model to move from case specifics to broader understandings of curriculum change I argue that cognisance of the relationship between informal and formal knowledge is a key issue in music education. Because of the growing role of popular music in the classroom (Green, 2008) providing access for students to varied forms of knowledge has become an important aspect of teachers??? work. This work involves making connections between aspects of the everyday informal knowledge that many music students bring to the classroom, and the conceptual knowledge of the discipline. The challenges involved in reframing informal knowledge may be relevant in other curriculum areas, particularly where knowledge content is susceptible to socio-cultural influences.

    View record details
  • Informal and formal knowledge: The curriculum conception of two rock graduates

    McPhail, Graham (2013-03)

    Journal article
    The University of Auckland Library

    Informal learning has become a prominent theme in music education literature in recent times. Many writers have called for a new emphasis on informal knowledge and pedagogy as the way forward for music education. The position taken in this paper is that a central issue for music education is the accommodation of a tension between types of knowledge and the ways of knowing strongly associated with popular and classical of music ??? socially acquired informal knowledge and socially developed but formally acquired disciplinary knowledge. Approaches to curriculum conception and realisation observed in a recent series of case studies in New Zealand secondary schools suggest that a key factor in student engagement is the degree to which teachers can create links between informal and formal knowledge so that students??? understanding and conceptual abilities can be extended across these knowledge boundaries. The teaching approaches of two recent graduates in rock music are discussed to support the social realist argument that a ???progressive??? approach to curriculum involves creating links between informal and formal knowledge rather than replacing one with the other or dissolving the boundaries between them. Through seeing the two types of knowledge as necessarily interconnected within educational contexts, the epistemic integrity of classroom music is maintained. In this way students are able to recognise themselves and their aspirations while also recognising the potential and power of the foundational knowledge of the discipline.

    View record details
  • Developing student autonomy in the one-to-one music lesson

    McPhail, Graham (2013-05-01)

    Journal article
    The University of Auckland Library

    As a practitioner in both the classroom and in the instrumental studio, I am interested in how one educational context might inform the other. Within an action research paradigm, I gave a violin lesson in front of colleagues as a means to gain feedback and to open up discussion on the concept of student autonomy within the one-to-one lesson. The enquiry was informed by recent literature within the music education field that calls for a new emphasis on informal learning principles and pedagogy for engaging students. I consider some of the key concepts of informal music learning from the influential Musical Futures classroom project as a means to reflect on the potential for developing student autonomy within the instrumental teaching context. Forms of knowledge and the distinction between knowledge content (the curriculum or ???the what??? of teaching) and the pedagogy (???the how???) are identified as significant conceptual distinctions for theorizing and realizing teachers??? work in the one-to-one context. I suggest that while traditional instrumental teaching models can be enhanced by informal and constructivist approaches to pedagogy, there are limits to the application of these principles because of the nature of the knowledge required in this learning context.

    View record details
  • The canon or the kids: Teachers and the recontextualisation of classical and popular music in the secondary curriculum

    McPhail, Graham (2013-06)

    Journal article
    The University of Auckland Library

    This article reports on some of the findings from case studies conducted with six secondary school music teachers in New Zealand. The purpose of the study was to investigate and explain the ways in which teachers manage the relationship between classical and popular music in their elective classroom programs, utilizing a theoretical framework drawn from the work of educational sociologist Basil Bernstein and more recent social realist theory. In each case, the focus of the research was the teacher and the influences on their curriculum decision-making. Students in each music department were interviewed to triangulate teacher interviews and observations. The findings indicate that a significant tension is present between the affirmation and validation of students??? musical interests and pre-existing skills, and the development of the knowledge considered fundamental within the discipline. It is teachers??? ability to ???find a balance??? between these central concerns of their educational work that is significant in maintaining the epistemic integrity of a subject which has become strongly influenced by socio-cultural influences.

    View record details
  • Engagement and recruitment of M??ori and non-M??ori people of advanced age to LiLACS NZ

    Dyall, Lorna; Kepa, M; Hayman, Karen; Teh, Ruth; Moyes, Simon; Broad, Joanna; Kerse, Ngaire (2013-04)

    Journal article
    The University of Auckland Library

    Life and Living in Advanced Age: A Cohort Study in New Zealand (LiLACS NZ) aims to determine the predictors of successful advanced ageing and understand the trajectories of wellbeing in advanced age. This paper reports recruitment strategies used to enrol 600 M??ori aged 80-90 years and 600 non-M??ori aged 85 years living within a defined geographic boundary.

    View record details
  • Design of optimized hypoxia-activated prodrugs using pharmacokinetic/pharmacodynamic modeling

    Foehrenbacher, A; Secomb, TW; Wilson, William; Hicks, Kevin (2013-12-27)

    Journal article
    The University of Auckland Library

    Hypoxia contributes to resistance of tumors to some cytotoxic drugs and to radiotherapy, but can in principle be exploited with hypoxia-activated prodrugs (HAP). HAP in clinical development fall into two broad groups. Class I HAP (like the benzotriazine N-oxides tirapazamine and SN30000), are activated under relatively mild hypoxia. In contrast, Class II HAP (such as the nitro compounds PR-104A or TH-302) are maximally activated only under extreme hypoxia, but their active metabolites (effectors) diffuse to cells at intermediate O2 and thus also eliminate moderately hypoxic cells. Here, we use a spatially resolved pharmacokinetic/pharmacodynamic (SR-PK/PD) model to compare these two strategies and to identify the features required in an optimal Class II HAP. The model uses a Green's function approach to calculate spatial and longitudinal gradients of O2, prodrug, and effector concentrations, and resulting killing in a digitized 3D tumor microregion to estimate activity as monotherapy and in combination with radiotherapy. An analogous model for a normal tissue with mild hypoxia and short intervessel distances (based on a cremaster muscle microvessel network) was used to estimate tumor selectivity of cell killing. This showed that Class II HAP offer advantages over Class I including higher tumor selectivity and greater freedom to vary prodrug diffusibility and rate of metabolic activation. The model suggests that the largest gains in class II HAP antitumor activity could be realized by optimizing effector stability and prodrug activation rates. We also use the model to show that diffusion of effector into blood vessels is unlikely to materially increase systemic exposure for realistic tumor burdens and effector clearances. However, we show that the tumor selectivity achievable by hypoxia-dependent prodrug activation alone is limited if dose-limiting normal tissues are even mildly hypoxic.

    View record details
  • Self-organizing roles on Agile software development teams

    Hoda, Rashina; Noble, J; Marshall, S (2013)

    Journal article
    The University of Auckland Library

    Self-organizing teams have been recognized and studied in various forms-as autonomous groups in socio-technical systems, enablers of organizational theories, agents of knowledge management, and as examples of complex-adaptive systems. Over the last decade, self-organizing teams have taken center stage in software engineering when they were incorporated as a hallmark of Agile methods. Despite the long and rich history of self-organizing teams and their recent popularity with Agile methods, there has been little research on the topic within software wngineering. Particularly, there is a dearth of research on how Agile teams organize themselves in practice. Through a Grounded Theory research involving 58 Agile practitioners from 23 software organizations in New Zealand and India over a period of four years, we identified informal, implicit, transient, and spontaneous roles that make Agile teams self-organizing. These roles-Mentor, Coordinator, Translator, Champion, Promoter, and Terminator-are focused toward providing initial guidance and encouraging continued adherence to Agile methods, effectively managing customer expectations and coordinating customer collaboration, securing and sustaining senior management support, and identifying and removing team members threatening the self-organizing ability of the team. Understanding these roles will help software development teams and their managers better comprehend and execute their roles and responsibilities as a self-organizing team.

    View record details
  • MedTouch: Towards the development of smartphone-based software solutions for health care self-management

    Caprio, A; Kim, J; Hoda, Rashina; Miller, D (2013)

    Conference item
    The University of Auckland Library

    Health care systems around the world today suffer from a number of critical challenges. These include increasing health care costs, declining number of health care professionals, and a growing number of old and frail people that require medical support but lack ability to self-manage their medication compliance. Although several health care solutions exist in the market today, most of them only enable the patients to keep track of their general fitness or provide information on medical issues. None of them focus on providing a personalised health care management system that bridges the gap between patients and their health care providers. We present MedTouch ??? a smartphone-based software application that enables patients to manage their vital statistics information, medical prescriptions including reminder alarms, transmission of medical information to health care providers including photographs, and application settings. We designed and developed this application iteratively using Scrum software development method in close collaboration with a representative from Orion Health ??? a global software company providing health care system solutions. We also conducted functional testing and usability evaluations followed by further refinements to the system.

    View record details
  • Barriers to learning in agile software development projects

    Babb, J; Hoda, Rashina; N??rbjerg, J (2013)

    Conference item
    The University of Auckland Library

    The adoption of agile methods promises many advantages for individual, team, and organizational learning. However, environmental, structural, and organizational/cultural constraints often find teams adapting agile software development methods rather than engaging in full adoption. We present results from two qualitative studies of teams and organizations that have, in many cases, adapted agile software methods to suit their needs through the omission or alteration of aspects of the method. In many cases, aspects of an agile method that are most related to learning were those that were modified or omitted. This paper utilizes the results of these studies to identify common and emergent barriers to learning. Often these barriers to learning exist according to organizational culture and the extent to which that culture influences attitudes, norms, and behaviors pertaining to learning. We present these barriers to learning and provide insight to the causes, effects, and potential ameliorations for these barriers.

    View record details
  • 6th International Workshop on Cooperative and Human Aspects of Software Engineering (CHASE 2013)

    Prikladnicki, R; Hoda, Rashina; Cataldo, M; Sharp, H; Dittrich, Y; De Souza, C (2013)

    Conference item
    The University of Auckland Library

    Software is created by people for people working in a range of environments and under various conditions. Understanding the cooperative and human aspects of software development is crucial in order to comprehend how methods and tools are used, and thereby improve the creation and maintenance of software. Both researchers and practitioners have recognized the need to investigate these aspects, but the results of such investigations are dispersed in different conferences and communities. The goal of this workshop is to provide a forum for discussing high quality research on human and cooperative aspects of software engineering. We aim to provide both a meeting place for the community and the possibility for researchers interested in joining the field to present and discuss their work in progress and to get an overview over the field.

    View record details
  • Synthesis and in vitro and in vivo evaluation of antimalarial polyamines

    Liew, Lydia; Pearce, Allison; Kaiser, M; Copp, Brent (2013-11)

    Journal article
    The University of Auckland Library

    We recently reported that 1,14-diphenylacetamide derivatives of spermine exhibit potent nM in vitro growth inhibition properties of Plasmodium falciparum. In an effort to expand the structure-activity relationship of this compound class towards malaria, we have prepared and biologically tested a library that includes benzamide and 3-phenylpropanamide 'capping acid' groups, and polyamines that include spermine (PA3-4-3) and chain extended analogues PA3-8-3 and PA3-12-3. 2-Hydroxy and 2,5-dimethoxy analogues were typically found to exhibit the most potent activity towards the dual drug resistant strain K1 of P. falciparum with IC50's in the range of 1.3-9.5 nM, and selectivity indices (SI) of 42,300 to 4880. In vivo evaluation of three analogues against Plasmodium berghei was undertaken, with one demonstrating a modest 27.9% reduction in parasitaemia.

    View record details
  • The unfulfilled pedagogical promise of the dialogic in writing: Intertextual writing instruction for diverse settings

    Jesson, Rebecca; Parr, Judith; McNaughton, Stuart (2013)

    Book item
    The University of Auckland Library

    In this chapter, the authors use writing as a site to consider the intersection between culture and effective pedagogy. They identify the general principles surrounding pedagogy, which is considered to be culturally responsive, and then examine the research to consider these principles specifically with regard to the teaching of writing in linguistically and culturally diverse contexts. The chapter explores ways to incorporate deliberately the general principles of culturally responsive pedagogy in the teaching of writing. It also offers a view of writing and writing instruction as dialogic, with the aim of incorporating students' existing knowledge and practices. By considering students' intertextual histories as a key resource for writing, the chapter considers that there is potential to develop instruction that is contingent upon and responsive to students' various experiences with texts.

    View record details
  • Effects of supercritical carbon dioxide processing on optical crystallinity and in vitro release of progesterone and Gelucire 44/14 solid and semi-solid dispersions

    Falconer, James; Wen, Jingyuan; Zargar-Shoshtari, S; Chen, John; Farid, Mohammed; Young, S; Alany, Raid (2013)

    Journal article
    The University of Auckland Library

    The aim of this study was to determine the effect of supercritical carbon dioxide (SC-CO2) on the crystallinity and drug release of Gelucire 44/14-based endogenous progesterone (PGN) dispersion systems. The light scattering from PGN crystals incorporated in Gelucire 44/14 was imaged using optical microscopy. In vitro dissolution was used to determine the release kinetics of PGN, Gelucire 44/14, incorporated by a supercritical fluid (SCF) method. Release profiles were evaluated according to zero-order, first-order, Higuchi, Krosmeyer-Peppas, and dual first-order models. The dual first-order release model illustrated two distinct release rates: an initial rapid release followed by a slow diffusion of PGN from the dispersion systems. The dual first-order release model adds a new tool to the elucidation of release mechanisms from lipid and micelle-forming-based dispersion systems, where parallel processes contribute to drug release.

    View record details
  • Classroom assessment in writing

    Parr, Judith (2013)

    Book item
    The University of Auckland Library

    View record details
  • Evaluation as a double-edged sword: Building schools??? evaluative capability while evaluating their efforts in raising achievement

    Parr, Judith; Timperley, Helen (2013)

    Book item
    The University of Auckland Library

    View record details