title: Refinement of Mg alloys crystal structure via Nb-based heterogeneous substrates for improved performances

authors: Bolzoni, Leandro

abstract: Lightness and high specific strength make magnesium alloys ideal materials for the transportation industry, especially the automotive sector that is struggling to cope with the everyday more stringent regulations on emission of carbon dioxide. Wrought magnesium alloys are difficult to deform because of the few active slip systems characteristic of their hexagonal close-packed lattice. Consequently, most of the commercially available magnesium alloys are alloys based on the Mg-Al binary system used in casting processes. The improvement of the mechanical properties of these alloys cannot be achieved by means of grain refinement using Zr due to the formation of Zr aluminides. In this study we propose a novel chemical composition that can refine all types of Mg alloys as proved in the Al-containing AM50 Mg alloy. We demonstrate that Nb-B inoculation of Mg alloys promotes the formation of heterogeneously nucleated primary α-Mg grains leading to the reduction of the grain size and this is obtained over a wide range of cooling rates. We also show that the grain refinement achieved leads to the improvement of the properties of high pressure die cast Mg automotive components and has the potential to enhance the mechanical properties of cast Mg alloys.

text: Refinement of Mg alloys crystal structure via Nb-based heterogeneous substrates for improved performances Lightness and high specific strength make magnesium alloys ideal materials for the transportation industry, especially the automotive sector that is struggling to cope with the everyday more stringent regulations on emission of carbon dioxide. Wrought magnesium alloys are difficult to deform because of the few active slip systems characteristic of their hexagonal close-packed lattice. Consequently, most of the commercially available magnesium alloys are alloys based on the Mg-Al binary system used in casting processes. The improvement of the mechanical properties of these alloys cannot be achieved by means of grain refinement using Zr due to the formation of Zr aluminides. In this study we propose a novel chemical composition that can refine all types of Mg alloys as proved in the Al-containing AM50 Mg alloy. We demonstrate that Nb-B inoculation of Mg alloys promotes the formation of heterogeneously nucleated primary α-Mg grains leading to the reduction of the grain size and this is obtained over a wide range of cooling rates. We also show that the grain refinement achieved leads to the improvement of the properties of high pressure die cast Mg automotive components and has the potential to enhance the mechanical properties of cast Mg alloys.

year: 2018

title: Management of the University of Waikato campus lakes: Final report

authors: Hicks, Brendan J.

subjects: water quality

abstract: There are three small shallow lakes on the University of Waikato campus, and all have high nutrient loadings, creating ideal conditions for plant algal growth.  These lakes were created by excavation during construction of the university for the purposes of stormwater detention.  Water quality in the lakes has been a matter of concern to the University of Waikato Site Committee for a number of years, and the concern intensifies in late 2000 with the commissioning of the WEL Energy Academy of Performing Arts, which was built with a view over Knighton Lake.

text: Management of the University of Waikato campus lakes: Final report There are three small shallow lakes on the University of Waikato campus, and all have high nutrient loadings, creating ideal conditions for plant algal growth.  These lakes were created by excavation during construction of the university for the purposes of stormwater detention.  Water quality in the lakes has been a matter of concern to the University of Waikato Site Committee for a number of years, and the concern intensifies in late 2000 with the commissioning of the WEL Energy Academy of Performing Arts, which was built with a view over Knighton Lake.

year: 2002-11

title: Beyond structuralism: Exploring a semantic based approach for describing the Māori language in grammar books and textbooks for pedagogical purposes

authors: Taiapa, Michael William

subjects: Māori

abstract: Since the 1950s, the advancements and developments in English language studies has had a profound impact on its description that has made it less syntactically driven and more communicatively oriented. This has the potential to influence language description moving it from a purely structurally focused orientation to a more semantically focused one that could influence pedagogic outcomes in more meaningful and useful ways. Nevertheless, in the case of the Māori language, its description has largely focused on structure linguistics that was prevalent in the 19th and early 20th centuries. There has been very little focus on a semantic description and this, in turn, is reflected in grammar books and textbooks on te reo. This thesis set out to explore a semantic approach to describe te reo and to rethink how this type of description may be realized and included in the design of grammar books and textbooks for the teaching and learning of te reo in the broader field of second language pedagogy and acquisition. The thesis also includes a practical component in which a small sample of Māori language teachers were interviewed to determine how linguistic and/ or semantic approaches to describe te reo may have or have impacted on their own beliefs, attitudes, and teaching practices (See, Chapter 7). Thus, it is argued here that research-based studies, advancements, and developments in language descriptions over the past five decades (See, for example, Council of Europe, 1949; Fillmore, 1967; Longacre, 1968; & Crombie, 1985b) should play central roles in the design of a semantic based description of the Māori language from which a linguistic based description can significantly benefit.

text: Beyond structuralism: Exploring a semantic based approach for describing the Māori language in grammar books and textbooks for pedagogical purposes Since the 1950s, the advancements and developments in English language studies has had a profound impact on its description that has made it less syntactically driven and more communicatively oriented. This has the potential to influence language description moving it from a purely structurally focused orientation to a more semantically focused one that could influence pedagogic outcomes in more meaningful and useful ways. Nevertheless, in the case of the Māori language, its description has largely focused on structure linguistics that was prevalent in the 19th and early 20th centuries. There has been very little focus on a semantic description and this, in turn, is reflected in grammar books and textbooks on te reo. This thesis set out to explore a semantic approach to describe te reo and to rethink how this type of description may be realized and included in the design of grammar books and textbooks for the teaching and learning of te reo in the broader field of second language pedagogy and acquisition. The thesis also includes a practical component in which a small sample of Māori language teachers were interviewed to determine how linguistic and/ or semantic approaches to describe te reo may have or have impacted on their own beliefs, attitudes, and teaching practices (See, Chapter 7). Thus, it is argued here that research-based studies, advancements, and developments in language descriptions over the past five decades (See, for example, Council of Europe, 1949; Fillmore, 1967; Longacre, 1968; & Crombie, 1985b) should play central roles in the design of a semantic based description of the Māori language from which a linguistic based description can significantly benefit.

year: 2023