title: Transport theory and the WKB approximation for interplanetary MHD fluctuations

authors: Matthaeus, William H.

abstract: An alternative approach, based on a multiple scale analysis, is presented in order to reconcile the traditional WKB approach to the modeling of interplanetary fluctuations in a mildly inhomogeneous large-scale flow with a more recently developed transport theory. This enables us to compare directly, at a formal level, the inherent structure of the two models. In the case of noninteracting, incompressible (Alfvén) waves, the principle difference between the two models is the presence of leading-order couplings (called “mixing effects”) in the non-WKB turbulence model which are absent in a WKB development. Within the context of linearized MHD, two cases have been identified for which the leading order non-WKB “mixing term” does not vanish at zero wavelength. For these cases the WKB expansion is divergent, whereas the multiple-scale theory is well behaved. We have thus established that the WKB results are contained within the multiple-scale theory, but leading order mixing effects, which are likely to have important observational consequences, can never be recovered in the WKB style expansion. Properties of the higher-order terms in each expansion are also discussed, leading to the conclusion that the non-WKB hierarchy may be applicable even when the scale separation parameter is not small.

text: Transport theory and the WKB approximation for interplanetary MHD fluctuations An alternative approach, based on a multiple scale analysis, is presented in order to reconcile the traditional WKB approach to the modeling of interplanetary fluctuations in a mildly inhomogeneous large-scale flow with a more recently developed transport theory. This enables us to compare directly, at a formal level, the inherent structure of the two models. In the case of noninteracting, incompressible (Alfvén) waves, the principle difference between the two models is the presence of leading-order couplings (called “mixing effects”) in the non-WKB turbulence model which are absent in a WKB development. Within the context of linearized MHD, two cases have been identified for which the leading order non-WKB “mixing term” does not vanish at zero wavelength. For these cases the WKB expansion is divergent, whereas the multiple-scale theory is well behaved. We have thus established that the WKB results are contained within the multiple-scale theory, but leading order mixing effects, which are likely to have important observational consequences, can never be recovered in the WKB style expansion. Properties of the higher-order terms in each expansion are also discussed, leading to the conclusion that the non-WKB hierarchy may be applicable even when the scale separation parameter is not small.

year: 1994

title: Design of Building Integrated Photovoltaic Product for Long Run Metal Roofing

authors: McGuinness, Benjamin John

abstract: In this study an innovative concept for a building integrated photovoltaic (BIPV) product was generated and verified at the University of Waikato in partnership with Dimond Roofing. The concept is based on a new principle which consists of laminating solar cells directly to a COLORSTEEL substrate, with a thin polymer cover, and folding this post-lamination into a profile which is capable of mating with standard long run metal roofing profiles. There were two major unknowns associated with the new concept which needed to be verified. Firstly, the suitability of laminating directly onto COLORSTEEL was in question as this material has not been used for this purpose before. More importantly, it was unsure whether the laminate would withstand the folding process without causing damage to the cells or other laminate materials. The issue of laminating to COLORSTEEL was addressed experimentally by producing small scale COLORSTEEL-EVA laminates. T peel tests were performed on samples from two different laminates - one which consisted of COLORSTEEL which had not undergone any kind of surface treatment, and another which was subjected to flame treatment to increase its surface energy. The flame treated sample exhibited a 7 fold increase in adhesion strength over the untreated sample, with average adhesion values of 56 N/cm, which is comparable to proven materials currently used in commercial quality photovoltaic modules. Untreated COLORSTEEL is not suitable for PV laminates. Further optimization of the treatment and lamination processes is likely to produce laminates with even greater adhesion strengths. Subsequently, it was necessary to fabricate equipment to replicate the commercial lamination process in order to produce laminates of high quality. These laminates were then folded on a hand brake to determine the feasibility of forming them into shapes capable of mating with existing metal roofing profiles. Folds were able to be started very close to the edge of the cell, even as close as 1 mm, without affecting the performance of the laminate, or causing any damage to the cell or laminate materials. This study was successful in designing an innovative BIPV product with huge potential to succeed in today’s market. It was shown that the product is worth further investigation, therefore it is recommended that larger scale prototypes are produced and subjected to a range of testing.

text: Design of Building Integrated Photovoltaic Product for Long Run Metal Roofing In this study an innovative concept for a building integrated photovoltaic (BIPV) product was generated and verified at the University of Waikato in partnership with Dimond Roofing. The concept is based on a new principle which consists of laminating solar cells directly to a COLORSTEEL substrate, with a thin polymer cover, and folding this post-lamination into a profile which is capable of mating with standard long run metal roofing profiles. There were two major unknowns associated with the new concept which needed to be verified. Firstly, the suitability of laminating directly onto COLORSTEEL was in question as this material has not been used for this purpose before. More importantly, it was unsure whether the laminate would withstand the folding process without causing damage to the cells or other laminate materials. The issue of laminating to COLORSTEEL was addressed experimentally by producing small scale COLORSTEEL-EVA laminates. T peel tests were performed on samples from two different laminates - one which consisted of COLORSTEEL which had not undergone any kind of surface treatment, and another which was subjected to flame treatment to increase its surface energy. The flame treated sample exhibited a 7 fold increase in adhesion strength over the untreated sample, with average adhesion values of 56 N/cm, which is comparable to proven materials currently used in commercial quality photovoltaic modules. Untreated COLORSTEEL is not suitable for PV laminates. Further optimization of the treatment and lamination processes is likely to produce laminates with even greater adhesion strengths. Subsequently, it was necessary to fabricate equipment to replicate the commercial lamination process in order to produce laminates of high quality. These laminates were then folded on a hand brake to determine the feasibility of forming them into shapes capable of mating with existing metal roofing profiles. Folds were able to be started very close to the edge of the cell, even as close as 1 mm, without affecting the performance of the laminate, or causing any damage to the cell or laminate materials. This study was successful in designing an innovative BIPV product with huge potential to succeed in today’s market. It was shown that the product is worth further investigation, therefore it is recommended that larger scale prototypes are produced and subjected to a range of testing.

year: 2011

title: Interpreting & practicing kaupapa Māori research in a community setting: The in’s and out’s

authors: Thompson, Keri

subjects: Māori

abstract: Pou Tuia Rangahau is a unique community based research unit based within a kaupapa Māori organisation. Kaupapa Māori methodologies are utilised, with the importance of these methodologies being that Māori are defining the process, doing the research for and about Māori, with the eventual outcome being meaningful to Māori. This paper is placed within this wider context of Kaupapa Māori and how it applies to the practice of research in particular. We discuss how we interpret and practice Kaupapa Māori Research (KMR) within an urban community based organisation by highlighting a particular piece of research that was undertaken by Pou Tuia Rangahau, the Research Unit of Te Runanga O Kirikiriroa Trust Inc.

text: Interpreting & practicing kaupapa Māori research in a community setting: The in’s and out’s Pou Tuia Rangahau is a unique community based research unit based within a kaupapa Māori organisation. Kaupapa Māori methodologies are utilised, with the importance of these methodologies being that Māori are defining the process, doing the research for and about Māori, with the eventual outcome being meaningful to Māori. This paper is placed within this wider context of Kaupapa Māori and how it applies to the practice of research in particular. We discuss how we interpret and practice Kaupapa Māori Research (KMR) within an urban community based organisation by highlighting a particular piece of research that was undertaken by Pou Tuia Rangahau, the Research Unit of Te Runanga O Kirikiriroa Trust Inc.

year: 2008