title: αₙ-Designs

authors: Ruggiero, Katya

abstract: This thesis defines a broad class of resolvable incomplete block designs for multifactor experiments, called αₙ-designs. A general methodology for their construction is described and is shown to be a natural extension of the method used by Patterson and Williams (1976) in their construction of α-designs. In fact, the class of α-designs are a special case of αₙ-designs with n = 1. 

The family of αₙ-designs was primarily developed for their use in factorial experiments. While they are particularly suitable for this purpose, for some combinations of design parameters they also provide more efficient designs than the best available α-designs.

Algorithms for the generation of efficient designs require computationally expensive eigenvalue calculations. Therefore, considerable attention is devoted to the study of the structural properties of αₙ-designs and how these can be used to develop computationally fast algorithms. In this endeavour it is shown that the treatment concurrence and information matrices have an important property known as BⁿC-structure. This is used to derive a closed form mathematical expression for the average efficiency factor of any generalized interaction. It is further shown that this expression can be written recursively. These results, combined with the fact than an αₙ-design is completely specified by a small generating array, mean that computer search algorithms can be developed to quickly find highly efficient designs.

A desirable feature in a factorial design is the property of orthogonal factorial structure. The family of αₙ-designs do not, in general, admit this property. However, another class of n-dimensional cyclic designs, known as n-cyclic designs, suitable for non-resolvable designs for factorial experiments are also considered in this thesis. They possess orthogonal factorial structure and include a sizeable subset of designs which are resolvable. These resolvable n-cyclic designs are shown to be αₙ-designs.

The discovery and subsequent development of the family of αₙ-designs has stimulated a new set of interesting questions in relation to factorial experiments. These are discussed at the end of the thesis.

text: αₙ-Designs This thesis defines a broad class of resolvable incomplete block designs for multifactor experiments, called αₙ-designs. A general methodology for their construction is described and is shown to be a natural extension of the method used by Patterson and Williams (1976) in their construction of α-designs. In fact, the class of α-designs are a special case of αₙ-designs with n = 1. 

The family of αₙ-designs was primarily developed for their use in factorial experiments. While they are particularly suitable for this purpose, for some combinations of design parameters they also provide more efficient designs than the best available α-designs.

Algorithms for the generation of efficient designs require computationally expensive eigenvalue calculations. Therefore, considerable attention is devoted to the study of the structural properties of αₙ-designs and how these can be used to develop computationally fast algorithms. In this endeavour it is shown that the treatment concurrence and information matrices have an important property known as BⁿC-structure. This is used to derive a closed form mathematical expression for the average efficiency factor of any generalized interaction. It is further shown that this expression can be written recursively. These results, combined with the fact than an αₙ-design is completely specified by a small generating array, mean that computer search algorithms can be developed to quickly find highly efficient designs.

A desirable feature in a factorial design is the property of orthogonal factorial structure. The family of αₙ-designs do not, in general, admit this property. However, another class of n-dimensional cyclic designs, known as n-cyclic designs, suitable for non-resolvable designs for factorial experiments are also considered in this thesis. They possess orthogonal factorial structure and include a sizeable subset of designs which are resolvable. These resolvable n-cyclic designs are shown to be αₙ-designs.

The discovery and subsequent development of the family of αₙ-designs has stimulated a new set of interesting questions in relation to factorial experiments. These are discussed at the end of the thesis.

year: 2000

title: Microbially induced calcium carbonate precipitation: a widespread phenomenon in the biological world

authors: Seifan, Mostafa

subjects: Science & Technology

abstract: Biodeposition of minerals is a widespread phenomenon in the biological world and is mediated by bacteria, fungi, protists, and plants. Calcium carbonate is one of those minerals that naturally precipitate as a by-product of microbial metabolic activities. Over recent years, microbially induced calcium carbonate precipitation (MICP) has been proposed as a potent solution to address many environmental and engineering issues. However, for being a viable alternative to conventional techniques as well as being financially and industrially competitive, various challenges need to be overcome. In this review, the detailed metabolic pathways, including ammonification of amino acids, dissimilatory reduction of nitrate, and urea degradation (ureolysis), along with the potent bacteria and the favorable conditions for precipitation of calcium carbonate, are explained. Moreover, this review highlights the potential environmental and engineering applications of MICP, including restoration of stones and concrete, improvement of soil properties, sand consolidation, bioremediation of contaminants, and carbon dioxide sequestration. The key research and development questions necessary for near future large-scale applications of this innovative technology are also discussed.

text: Microbially induced calcium carbonate precipitation: a widespread phenomenon in the biological world Biodeposition of minerals is a widespread phenomenon in the biological world and is mediated by bacteria, fungi, protists, and plants. Calcium carbonate is one of those minerals that naturally precipitate as a by-product of microbial metabolic activities. Over recent years, microbially induced calcium carbonate precipitation (MICP) has been proposed as a potent solution to address many environmental and engineering issues. However, for being a viable alternative to conventional techniques as well as being financially and industrially competitive, various challenges need to be overcome. In this review, the detailed metabolic pathways, including ammonification of amino acids, dissimilatory reduction of nitrate, and urea degradation (ureolysis), along with the potent bacteria and the favorable conditions for precipitation of calcium carbonate, are explained. Moreover, this review highlights the potential environmental and engineering applications of MICP, including restoration of stones and concrete, improvement of soil properties, sand consolidation, bioremediation of contaminants, and carbon dioxide sequestration. The key research and development questions necessary for near future large-scale applications of this innovative technology are also discussed.

year: 2019

title: Putting Sylvia in her place: history, geographical theory and the “New” Education

authors: Middleton, Sue

subjects: Sylvia Ashton-Warner

abstract: New Zealander Sylvia Ashton-Warner, a teacher in remote rural Mori schools in the 1940s-1950s, became internationally renowned as a novelist and educational theorist. Earlier commentators portrayed her educational theory as in conflict with those of her time and place, but recent studies conceptualise them as enabled by it. While space/place has often been considered the preserve of the geographer and time that of the historian, Henri Lefebvre and others suggest that: “these issues need to be thought together rather than separately” and that macro-, meso- and micro-levels of analysis be engaged simultaneously. The author traces how conceptual, linguistic, sensory and intellectual resources of the global “New Education” movement extended into the tiny bush-encircled Mori communities in which Sylvia taught and wrote in the 1940s-1950s and surfaced in her writing. The article zooms in and out between the “the immensity of the global” (the New Education, the Second World War) and “the intimately tiny” (her classroom and home). The “data” include Sylvia's non-fiction education texts and official documents of her time: school curricula, education policy documents, Ministerial and Inspectors' reports. What Lefebvre terms a “Rhythm analysis” of Ashton-Warner's educational writing shows intermingled pulses of domestic life, routines of educational bureaucracy, cycles of nature, and cataclysms of world events. It is important for historians to study “the where rather than just the when with location and landscape central parts of the analysis”.

text: Putting Sylvia in her place: history, geographical theory and the “New” Education New Zealander Sylvia Ashton-Warner, a teacher in remote rural Mori schools in the 1940s-1950s, became internationally renowned as a novelist and educational theorist. Earlier commentators portrayed her educational theory as in conflict with those of her time and place, but recent studies conceptualise them as enabled by it. While space/place has often been considered the preserve of the geographer and time that of the historian, Henri Lefebvre and others suggest that: “these issues need to be thought together rather than separately” and that macro-, meso- and micro-levels of analysis be engaged simultaneously. The author traces how conceptual, linguistic, sensory and intellectual resources of the global “New Education” movement extended into the tiny bush-encircled Mori communities in which Sylvia taught and wrote in the 1940s-1950s and surfaced in her writing. The article zooms in and out between the “the immensity of the global” (the New Education, the Second World War) and “the intimately tiny” (her classroom and home). The “data” include Sylvia's non-fiction education texts and official documents of her time: school curricula, education policy documents, Ministerial and Inspectors' reports. What Lefebvre terms a “Rhythm analysis” of Ashton-Warner's educational writing shows intermingled pulses of domestic life, routines of educational bureaucracy, cycles of nature, and cataclysms of world events. It is important for historians to study “the where rather than just the when with location and landscape central parts of the analysis”.

year: 2011