802 results for 1980, Doctoral

  • A study of some New Zealand natural products.

    Jogia, Madhu Kant (1985)

    Doctoral thesis
    University of Otago

    xii, 348 leaves :col. ill. ; 30 cm. Includes bibliographical references. University of Otago department: Chemistry

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  • The kinetics of mild acid hydrolysis of gluten and the functional properties of the modified proteins at various levels of hydrolysis : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Biotechnology at Massey University

    Higgins, John Joseph (1988)

    Doctoral thesis
    Massey University

    Gluten is the mixture of proteins remaining in wheat flour after starch and water soluble components have been extracted by washing. Its unique dough forming properties are due to the structure of the proteins. A feature of the protein is the high glutamine content, about 30% of the total amino acids. A number of studies have shown that gluten's properties of insolubility and water-binding can be substantially modified by mild acid hydrolysis. The principal effect of the mild acid treatment is to hydrolyse the amide side chain of glutamine such that the amide group is replaced by a carboxyl group. In addition, it is known that hydrolysis of peptide bonds can have a large influence on the functional properties of proteins. The aims of this study were to determine the kinetics of the acid catalysed deamidation and peptide bond hydrolysis reactions, and to comment on the resultant changes in functional properties. A statistically designed experiment was used to determine the effect of temperature, hydrogen ion concentration and gluten concentration. An initial rate analysis of the results showed that reactions could be described by equations of the form: Rate of amide bond hydrolysis = k1.[Amide][H+] and Rate of peptide bond hydrolysis = k2 [Peptide] [H+] where k = koe -E/R.1/T A stoichiometric analysis of the experimental data confirmed that hydrogen ions were consumed in both reactions. A numerical solution was developed to predict the extent of reaction with time. A computer program incorporating the solution was used to simulate the reaction and test the solution. The simulation results appeared to overestimate the progress of the reaction with time. A series of ten gluten powders, hydrolysed to different extents was prepared at small pilot scale. The composition of the samples was determined and compared with the extent of hydrolysis predicted by the reaction simulation. Reasonable agreement was achieved. A selection of the functional properties of the prepared samples was examined. The quantity of alkali required to dissolve each preparation to the extent of its solubility at pH 7.6 increased markedly with the extent of hydrolysis due to the additional carboxyl groups requiring neutralization. The flavour of each preparation was exanined. A cereal flavour was found to decrease with the extent of hydrolysis. A lingering bitter flavour was found to increase with the extent of hydrolysis. The solubility of all preparations at p H 7.6 in 0.1 M phosphate buffer increased with the extent of treatment so that the most hydrolysed samples were almost completely soluble. No (significant) difference was found between freeze dried and spray dried samples. Samples prepared without dialysis showed no solubility difference from those prepared with dialysis at a similar extent of hydrolysis. The hydrophobicity of the preparations was measured using two different fluorescent probes and was found to increase with the extent of hydrolysis. The emulsion-forming properties of the preparations were found to depend on the oil used in the test, as would be expected if hydrophobicity was equivalent to the hydrophile lipophile balance, which is commonly used to classify emulsifying agents. The preparations did not, however, show the additivity properties of emulsifiers. It was also shown that only the soluble portion of the preparations was responsible for emulsion formation. The possibility of achieving deamidation of gluten using the enzymes peptidoglutaminase I and II was examined. No activity against gluten or partially hydrolysed gluten was found.

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  • Infant crying : mothers' perceptions and affective reactions : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Education at Massey University

    Brennan, Michael Charles (1985)

    Doctoral thesis
    Massey University

    Two studies were conducted in order to examine three major issues arising from recent studies of mothers' reactions to their crying infants. These issues, which arise in connection with the Aversive Stimulus Model of crying, relate to (a) the relationships between cry characteristics and mothers' affective reactions to crying, (b) the variability of cry characteristics of individual infants, and (c) the influence of context on mothers' reactions to their infants' crying. Resting on the premise that the semantic differential is an appropriate technique for addressing these issues. Study A examined the relationships between three sets of semantic differential scales. These were the scales reported by Brennan and Kirkland (1983), which represent three dimensions labelled Affect, Potency, and Evaluation; the scales reported by Zeskind and Lester (1978); and the scales reported by Mehrabian and Russell (1974a), which represent three dimensions of emotion labelled Pleasantness/Unpleasantness, Degree of Arousal, and Dominance/Submissiveness. A combined factor analysis of cry ratings on these scales uncovered the factor structure of the Brennan and Kirkland scales and of the Mehrabian and Russell scales. The factor representing the Brennan and Kirkland Affect scales also represented both the Zeskind and Lester scales and the Mehrabian and Russell Pleasantness/Unpleasantness scales. The Brennan and Kirkland scales were found to effectively discriminate between perceptually different cry sounds. The Mehrabian and Russell scales, however, were found to be lacking in face validity and therefore unsuitable for use with cry sounds. Study B examined the perceptions and affective reactions of mothers listening to their own infants' cries, in two situations - in the home as the crying occurred, and in an experimental situation involving tape-recorded cry samples. The results indicate that: (a) mothers affective reactions to cries did not simply depend upon the aversiveness of the cry sounds, (b) mothers' affective reactions to cries were strongly associated with their attributions regarding the causes and consequences of the cries, (c) cries from the same infant and cries from different infants varied considerably with respect to their perceived characteristics and the types of affective reactions they evoked, and (d) ratings of the tape-recorded cry samples tended to over-emphasise the relationships between cry characteristics and mothers' affective reactions, and to under-represent the extent to which negative affective reactions were experienced by the mothers in the home situation. Several suggestions were made for future studies. These included the adoption of an individualised approach to study: (a) the cry repertoires of individual infants, (b) the types and patterns of affective reactions experienced by individual mothers, (c) mothers' attributions regarding to their own feelings and their infants' behaviors, and (d) the relationships between mothers perceptions, attributions, affective reactions, and actual caregiving behaviors.

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  • A comparative study of phosphofructokinase and tagatose 6-phosphate kinase from streptococcus lactis : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Biochemistry at Massey University

    Fordyce, Alison Mary (1982)

    Doctoral thesis
    Massey University

    In the lactic streptococci glucose is metabolised to lactic acid via the Embden-Meyerhof-Parnas (EMP) pathway. Metabolism of lactose and galactose in these organisms involves participation of the D-tagatose 6-phosphate pathway in which galactose 6-phosphate is metabolised to triose phosphates via tagatose derivatives. Phosphofructokinase (ATP : D-fructose 6-phosphate 1-phosphotransferase, E.C. 2.7.1.11) catalyses the ATP-dependent phosphorylation of fructose 6-phosphate in the EMP pathway. The analogous reaction in the tagatose 6-phosphate pathway, phosphorylation of tagatose 6-phosphate with ATP, is catalysed by a specific enzyme, tagatose 6-phosphate kinase. While phosphofructokinase (PFK) is known to be a major regulatory enzyme in carbohydrate metabolism in most organisms, little is known of the regulatory properties of tagatose 6-phosphate kinase (T6PK). PFK and T6PK were purified from Streptococcus lactis C10 PFK was purified to homogeneity (364-fold purification) by affinity chromatography on Blue-dextran-Sepharose. Unlike PFK, T6PK did not bind to Blue-dextran-Sepharose : a 136-fold purification was achieved using ammonium sulphate fractionation, gel filtration, and ion exchange chromatography. A study of some of the properties of PFK and T6PK from S. lactis C10 showed that these two enzymes are distinct proteins with different physical and kinetic characteristics. S. lactis PFK is a tetramer (MW 145,000 daltons) of identical subunits of molecular weight 33,500 daltons. It therefore appears structurally similar to other bacterial PFKs. T6PK from S. lactis has a molecular weight of approximately 114,000 daltons, a value similar to that of Staphylococcus aureus T6PK which is a dimer. S. lactis PFK exhibited the co-operative binding of F6P and inhibition by high concentrations of ATP relative to F6P which is typical of most bacterial and mammalian PFKs. F6P0.5. and Km (MgATP) values were 0.28 mM and 0.18 mM respectively. ADP stimulated PFK activity, shifting the sigmoidal saturation curve to a more hyperbolic form, with a corresponding decrease in nH. Ammonium and potassium ions also activated PFK, while activity was inhibited by AMP, PEP, FBP, T6P and inorganic phosphate. In contrast to PFK, T6PK showed no co-operative binding of sugar phosphate substrate and was less sensitive than PFK to ATP inhibition. Km values for T6P and MgATP were 0.16 mM and 0.4 mM respectively. Apart from ammonium and potassium ions, no activators of T6PK were found. Activity was inhibited by ADP, PEP, and FBP. PFK and T6PK could catalyse phosphorylation of both F6P and T6P although the enzymes showed a much greater affinity for their natural substrate. Maximum velocities attained were higher with the natural substrate than when the other sugar phosphate was used as substrate. Both enzymes showed similar pH optima and divalent cation requirement. Levels of PFK, T6PK, and Galactokinase (Gal K), enzymes of the Embden-Meyerhof-Parnas, Tagatose 6-phosphate, and Leloir pathways respectively, were measured in strains of S. lactis, S. cremoris, S. diacetylactis and S. faecalis grown on different sugars. Growth on lactose and galactose induced increased levels of T6PK and Gal K activity, galactose generally inducing higher levels of T6PK than lactose. In most strains, addition of glucose to media containing lactose or galactose resulted in lowered activities of Gal K, comparable to those in glucose-grown cells. In contrast, T6PK activity was generally not suppressed by growth on glucose plus lactose, while in growth on glucose plus galactose, T6PK activity was approximately 50% of the activity in cells grown on glucose alone. PFK activity was generally unaffected by the sugar in the growth medium. In spite of changes in specific activities of PFK and T6PK throughout the growth period of S. lactis, the ratio of PFK : T6PK remained fairly constant. The properties of S. lactis PFK and T6PK are compared to those of these enzymes in other bacteria, and the possible role of T6PK in regulation of carbohydrate metabolism in S. lactis is discussed.

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  • The life history strategy of Carex pumila Thunb. (Cyperaceae), a rhizomatous perennial pioneer species on the sand plains of the dune system of coastal Manawatu : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Botany

    Burgess, Robert Edward (1984)

    Doctoral thesis
    Massey University

    The life history strategy of Carex pumila Thunb. (Cyperaceae), a major colonist of raw moist sand on the sand plains of coastal Manawatu, New Zealand, is outlined. By virtue of the continuous formation of sand plains, sites suitable for colonization are a permanent feature of this habitat and vegetation of increasing seral maturity is represented at any one time across a series of adjoining deflation hollows and low dunes. It is proposed that the species is an r-strategist well suited to exposure, nutrient stress and seasonal flooding. Amelioration of these conditions by deliberate perturbation treatments resulted in this seral species responding in a way that ultimately lead to its more rapid demise. The species has a rhizomatous perennial growth habit. Tne modular construction of its rhizome system is described for the first time. Similarly, the occurrence of both long and short sympodial rhizome branches and of large-diameter sinker roots have not been previously described in the literature on this species. Its floral development appears to be environmentally cued. Emergence of inflorescences occurrs in early October. Maximum size of dissemules is obtained by early January. Subsequently seeds are shed and the shoots bearing them die. The species is essentially allogamous, although in a laboratory experiment, it was found to be partially self-compatible. Self-pollination must be expected in the field since neighbouring shoots are likely to be part of the same genet. Field studies are reported in which the performance of Carex pumila was monitored, firstly at sites of increasing seral maturity both in space and in time, and secondly in response to perturbation treatments. Populations showed a pattern of development that included a juvenile phase of rhizome expansion, an adolescent phase of increasing shoot density, a mature phase in which a proportion of the shoots were reproductive, and a senile phase of diminished growth and seed production. Phasic development was more protracted on the more stressed and more exposed sites. Other species more rapidly filled the space made available by the death and decay of Carex pumila shoots, than the colonist itself. As a pioneer, the species is doomed to extinction on the sites it colonizes. In a perturbation experiment, the sward mass of the total vegetation per unit area was increased at all sites by nitrogen fertilizer, applied as ammonium ions at a rate of 50 kg N / ha. Where the Carex pumila population was in a senile phase in an old deflation hollow, the increase was made mainly by other species. In younger populations on a low dune, the density of shoots and expanding buds of Carex pumila were markedly increased by the fertilizer treatment. Associated with this, a significant increase occurred in the proportion of the total dry weight of vegetative branches in rhizomes and in green leaves. A nitrogen limitation to seed yeild was indicated at the older low dune site. Here nitrogen fertilizer addition increased seed output per unit area by increasing both seed number per culm and seed size. By contrast on the younger low dune site, seed output per unit area was unchanged by the perturbation. In this population, reallocation of resources within fertile shoots, which was seen as an increased number of seeds per culm, was offset however by a reduction in fertile shoot density. Seed reproductive effort varied between 0 and 16% of total biomass, whereas rhizome allocation was more variable; up to 100% of biomass where the species was invading an embryonic deflation hollow. As a proportion of the biomass of fertile shoots alone, seed reproductive effort estimates of up to 32% were obtained. The post-anthesis photosynthetic contribution of female spikes to final seed weight was estimated at 26%, in a growth room experiment. This estimate is considered conservative given that final seed weight was not significantly reduced by defoliation and shading of the culm. Thus, the allocation of biomass to seeds cannot be considered a drain on the carbon resources of the plant that might otherwise be allocated to growth or some other plant function. Total nitrogen concentrations were dissimilar in different plant parts and, for comparable organs, between populations of different ages. Thus, allocation patterns to component parts based on dry weight and total nitrogen were different. Given that nitrogen was seen to be limiting growth in this seral habitat, the allocation of this resource is likely to be of greater significance in the evolution of life history strategies than is that of dry weight.

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  • An evaluation of microcomputer assisted instruction for teaching word recognition to mentally retarded adults : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Education, Faculty of Education, Palmerston North, New Zealand

    Ryba, Kenneth Allan (1980)

    Doctoral thesis
    Massey University

    This study compared the utility of computer assisted instruction with more conventional interpersonal tuition for teaching word recognition skills to mentally retarded adults. A second aspect of the research was to evaluate acquisition, retention, and transfer of learning using two common methods of instruction; these were errorless discrimination (word-focus only) and paired associate learning (picture-word focus). Recognition of words was selected as the experimental task on the basis that this was a practical academic area that traditionally involves large amounts of teaching time, primarily within the realm of drill and practice procedures. The sample comprised 52 subjects who were drawn from three special education facilities in Palmerston North, New Zealand (a Special School, and two Vocational Training Centres). Subjects were screened initially on tests of visual perception and letter discrimination to ensure that they possessed requisite skills to benefit from participation in training. Pre-testing was carried out to determine whether subjects were able to recall or recognize any of the words to be taught. All subjects entering the experiment knew two or less of 16 words selected for inclusion in the training programmes. Subjects were randomly assigned to computer assisted instruction or individual tuition groups with 26 persons placed in each group. Within each group, subjects were again randomly allocated to receive errorless discrimination or paired associate modes of instruction. This 2 X 2 classification resulted in 13 subjects being placed in each subgroup. Two modules each containing eight words were used for training. Both the individual instruction and computer groups were given a total of 10 training sessions, or five sessions for each of the two modules. A modified microcomputer was interfaced with a sound-on-slide projector to provide both audio and visual instruction. Parallel teaching programmes were developed for administration by computer or individual tuition. The first programme (errorless discrimination) required subjects to select target words from a series of increasingly complex word discriminations with no picture cues provided. A second teaching method (paired associate learning) involved the pairing of pictures and words. Subjects were instructed to select target words from a list of printed items that matched referent photographs. Thirteen senior special education students (Teachers College Graduates) carried out the individual training while the experimenter supervised the computer based programmes. Progress in training was assessed by comparing pre- and post-test performance on Word Recognition (verbal labelling), Word Identification (pointing on cue), and Picture-Word Matching. Transfer of learning was evaluated using situational tests requiring that subjects match printed words with real life objects. Tests of retention were conducted four weeks after completion of training. A repeated measures design was used with counterbalancing to control for possible confounding effects of list order (Modules). The findings revealed that both computer assisted instruction and interpersonal tuition resulted in very similar learning outcomes with regard to acquisition, retention, and transfer of learning. No reliable differences were found between the two groups or modes of instruction in terms of training method. It was advanced that some common features of programmed instruction (e.g. active participation, self-pacing, over-learning, and immediate feedback) may have accounted for these equal gains in performance. In respect to the question of the potential utility of microprocessor technology in special education, this research points to the efficacy of computer assisted instruction for drill and tutorial practice. Specifically, the computer provides a highly structured learning experience that has the potential to assist retarded learners in organising input materials. Evidence from this study suggests that computer related learning environments give the adult learner considerably more control of the teaching situation, and provide consistent reinforcement that is not so readily administered through conventional forms of instruction. Finally, it was proposed that the relatively impersonal, though highly interactive, nature of the computer may avoid the triggering of perceptions of failure that can impede performance of handicapped learners. This dissertation is dedicated to my wife, Beth, whose understanding and support provided me with the encouragement to complete this work.

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  • Wastewater effects on epilithon, particularly sewage fungus, and water quality in the Manawatu River, New Zealand : a thesis presented in partial fulfilment of the requirements of the degree Doctor of Philosophy in Biotechnology at Massey University

    Quinn, John Martin (1985)

    Doctoral thesis
    Massey University

    Epilithon development, in relation to the discharge of domestic sewage, dairy factory and meatworks wastewaters, and its effects on water quality were studied in laboratory channels and in the Manawatu River. During the three year period of the study the organic material inputs to this river were progressively reduced to meet the requirements of water rights designed to limit the in-river BOD5 to 5 g.m-3 at the end of a defined mixing zone with the objective of maintaining adequate oxygen levels and controlling sewage fungus growth. Laboratory channel studies demonstrated that, for a given BOD5 addition, untreated dairy factory wastewater increased the heterotrophic growth 2-3 times more than primary treated meatworks wastewater. Similar observations were made in the Manawatu River. These varied growth responses could be accounted for by the different relative contributions of dissolved and low molecular weight (< 1000 daltons) organic compounds in the different wastewaters. The dissolved or low molecular weight (determined after sample ultrafiltration) BOD5 therefore provide more reliable general sewage fungus control parameters than BOD5. Current velocity and spates had marked influences on the development of benthic communities. Maximum sewage fungus biomasses on the natural bed were observed at current velocities of 0.2 to 0.45 m.s-1. Short heterotrophic fronds occurred at the maximum current velocity investigated of 1.16 m.s-1. Small spates of up to 50 to 70 m.s-3 caused preferential sloughing of heterotrophs over epilithic phototrophs which had developed on concrete plates at river flows of approximately 25 m3.s-1. Flows in excess of approximately 150 m3.s-1 removed growths of Cladophora glomerata which had developed at sites where the pre-spate current velocity was 0.3 to 0.4 m.s-1. Much higher flows, in excess of 400 m3.s-1, were required to remove the dense growths of the macrophyte Potamogeton crispus. Observations of sewage fungus biomass at various depths in the Manawatu River and growth rates on both upper, sunlight exposed, and lower, shaded, surfaces of concrete plates suspended in the water column indicated that solar radiation inhibition of heterotrophic growth is not important in the Manawatu River. These heterotrophic growths in the river were replaced by heavy phototroph-dominated epilithon as organic concentrations were reduced. Both communities had significant impacts on the suspended biomass and dissolved oxygen levels in the river. A computer model simulating summer low flow conditions in the Manawatu River predicted that the river can sustain average respiration rates of 20 and 24 g 02 m-3 d-1 at mean river temperatures of 21°C to 12°C respectively without breaching the statutory minimum permissable dissolved oxygen concentration of 5 g.m-3. A multiple regression model of the factors influencing epilithon respiration was developed from in situ chamber studies of a range of epilithic community types. This gave adequate predictions when tested against measurements over reaches below the discharges and predicted that the benthic biomass resulting in the maximum permissible respiration rates decreased from approximately 143 g AFDW m-2 at 12°C to 34 g AFDW m-2 at 21°C. A management strategy limiting the organic, but not the nutrient, inputs to the Manawatu River was shown to be unlikely to ensure consistent maintenance of the statutory minimum dissolved oxygen concentration. The implications for management of the river are discussed,

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  • An evaluation of traditional staff development practices for implementing change in university teaching : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Education, Faculty of Education,

    Ashcroft, Eric Robert (1987)

    Doctoral thesis
    Massey University

    This study examined the effectiveness of different staff development practices in implementing change in tertiary teaching. It assessed the effects of participation in three modes of staff development on staff attitudes, knowledge and teaching behaviours relevant to the teaching role. In particular, the research investigated effects of traditional and alternative modes of staff development operating in a New Zealand university for the five year period from 1979 to 1983. A new four variable model of implementation composed of interdependent influencing factors, the learning process, system components and an innovation, was used. Specified change in an instructional role was defined as the criteria of success. Changes were grouped within the three interrelated categories of attitudes, knowledge and behaviour. This research indicates the efficacy of Inner-directed methods for implementing change in attitudes. Even marked changes in attitudes however were not accompanied by changes to knowledge or instructional behaviour. For acquisition of new knowledge and implementation of new behaviours it is proposed that specific training, based on individually relevant goals, effects and involvements is necessary. Finally it is proposed that consistent application of the principles of learning is necessary for implementation of innovations in the instructional role of academic staff.

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  • Physiological stress, smoltification and seawater adaptation in New Zealand's sockeye and quinnat salmon.

    Franklin, Craig E. (1989)

    Doctoral thesis
    University of Canterbury Library

    This study investigated smoltification and seawater adaptability of sockeye (Oncorhynchus nerka) and quinnat salmon (O. tshawytscha). Both species were introduced into New Zealand with an anadromous population of quinnat and a totally freshwater population of sockeye salmon becoming established. The sockeye were found to be capable of successfully adapting to sea water and appeared not to have lost their hypoosmoregulatory ability despite being landlocked for approximately 90 years. The physiological changes associated with smoltification and seawater adaptation were studied and were viewed in part with reference to physiological stress. Salmon exposed to a handling or temperature stressor showed an increase in plasma cortisol concentrations and depending on the severity of the stressor, a change in haematocrit and an osmotic imbalance could also result. The physiological state of the salmon (pre-smoltified, smoltified, desmoltified) was assessed in a variety of ways and the reliability of the parameters measured related to the seawater adaptability of the salmon. Increased gill Na+-K+-ATPase activity provided the best indicator of smoltification. Plasma cortisol concentrations also increased in smoltifying salmon. The seawater adaptability of the salmon was found to be dependent on both the degree of smoltification that had occurred in the salmon and on the temperature of the sea water. High seawater temperatures limited the ability of the salmon to successfully adapt. Rapid increases in plasma cortisol occurred when salmon were transferred directly to sea water, but returned to basal levels within 12 hours in the fish that successfully adapted. Plasma cortisol concentrations remained elevated in the salmon that failed to adapt to the sea water. Morphological changes in the gills of sockeye salmon that successfully and unsuccessfully adapted to sea water were also investigated.

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  • Three phase integrated load and harmonic flows.

    Callaghan, C. D. (1989)

    Doctoral thesis
    University of Canterbury Library

    This thesis investigates two algorithms for the steady state analysis of HVDC convertor plant. The first is an already well established frequency domain technique, known as IHA (Iterative Harmonic Analysis), and the investigation centres on the nature of the algorithm under divergent conditions. In particular, a mathematical analysis of the algorithm is used to prove that divergence of the algorithm is not necessarily indicative of a physical harmonic instability. The second algorithm is developed to exploit the IHA technique within the context of the three phase a.c.-d.c. loadflow as an alternative convertor model which incorporates (rather than ignores) the effects of harmonics. The resulting three phase integrated load and harmonic flow algorithm is a significant improvement on the existing single phase load & harmonic flow algorithms. Finally, the integrated algorithm is applied to two test systems drawn from the New Zealand primary network, and is shown to be a significant improvement over the IRA algorithm alone, resolving the inconsistencies which exist between the fundamental frequency and harmonic models of the convertor.

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  • Chert and dolomite in the Amuri Limestone Group and Woolshed Formation, Eastern Marlborough, New Zealand.

    Lawrence, Mark John Frederick (1989)

    Doctoral thesis
    University of Canterbury Library

    Chert and dolomite in sediments of coastal Marlborough occur in the detrital units of the Upper Iwitahi Group (Wool shed Formation (WF) and Claverley Sandstone - Late Cretaceous), and in Late Cretaceous – Early Tertiary micritic sediments (foraminiferal nannofossil oozes) of the Amuri Limestone Group (ALG). All sediments were deposited in a NW-SE trending trough. Chert and dolomite are generally restricted to what was the deepest part of the basin. There is a greater volume of chert than dolomite. Two chronologically and stratigraphically separated types of dolomite occur: concretions of aphanitic dolomite in the WF, and phaneritic, rhombic dolomite in beds, lenses, or disseminated in chert or micrite in the ALG. Both dolomite types are moderately well ordered but Ca-rich. Isotopic and elemental analyses indicate all dolomites formed in wholly marine sediments at temperatures <90 weight percent. The chert chemistry is consistent with replacement of primary carbonate and the expulsion of carbonate-bound elements from the site of chert formation, effectively diluting noncarbonate-bound insoluble residue. Formation was by precipitation of either opal-CT or quartz depending on SiO2 saturation conditions. Isotopic analyses indicate formation temperatures similar to those of dolomite. The SiO2 was initially derived from biogenic sources but large amounts are inferred to have been derived from the underlying WF. Clay mineral transformations in the WF produced SiO2-rich pore waters through which ALG sediments are thought to have compacted. Initiation of silica deposition resulted from localized oxidation of the H2S produced by SO42- reduction. Initially deposited silica provided sites for further chertification. Evidence for early chertification (such as differential compaction) have lead to development of a combined model for dolomite and chert formation in association with SO42- reduction. Although chert and dolomite both commenced nucleation early, the initial rate of dolomite crystallization exceeded that of silica. The extent of dolomitization was governed by the SO42- concentration in pore waters and by the availability of Mg2+. Where SO42- concentrations were too high no dolomite formed, only calcite recrystallized. Chertification, although slower than dolomitization, continued after the cessation of dolomite formation, certifying undolomitized beds or parts of beds, and the matrix between dolomite crystals. The extent of chertification was governed by the availability of SiO2 This model of contemporaneous chert and dolomite formation explains the alternation of chert and dolomite beds, the dissemination of dolomite in chert, and the distribution of chert and dolomite.

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  • Spectral analysis classification sonars

    de Roos, Dolf (1986)

    Doctoral thesis
    University of Canterbury Library

    Sonar target classification based on frequency-domain echo analysis is investigated. Conventional pulsed sonars are compared with continuous transmission frequency modulated (CTFM) sonars, and differences relating to target classification are discussed. A practical technique is introduced which eliminates the blind time inherent in CTFM technology. The value and implications of modelling underwater sonars in air are discussed and illustrated. The relative merits of auditory, visual and computer analysis of echoes are examined, and the effects of using two or more analysis methods simultaneously are investigated. Various statistical techniques for detecting and classifying targets are explored. It is seen that with present hardware limitations, a two-stage echo analysis approach offers the most efficient means of target classification. A novel design for three-section quarter-wavelength transducers is presented and evaluated. Their inherently flat frequency response makes these transducers well suited to broadband applications. The design philosophy and construction details of a Diver's Sonar and an underwater Classification Sonar are given. Sea trials reveal that using the Diver's Sonar, a blind-folded diver can successfully navigate in an unknown environment, and locate and classify targets; using the Classification Sonar, targets may be located and classified using either operators or computer software.

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  • Te Kohurau : continuity and change in a New Zealand rural district.

    Hall, Robert Russell (1987)

    Doctoral thesis
    University of Canterbury Library

    While the study of community has occupied sociologists for some time, the process of community formation and change has not been extensively explored. This dissertation addresses that deficiency by examining the process within a New Zealand rural district. The role of closure and communion are analysed using a framework developed from Weberian theory to highlight the dynamic interplay of contradiction and reinforcement existing between three sets of locality relationships: propinquity (community), property (class) and kinship (family). A key argument is that the process of community formation within a locality cannot be adequately understood without considering all three relations together, since they serve collectively to provide the parameters for closure and hence community formation. These theoretical issues are used to explore the historical development of the Kurow district from the time of European settlement (circa 1850) to the present day (1982). The development of the district was divided into periods (1850-90; 1890-1920; 1920-1950; and 1950-1982), and techniques of historical research were employed to reconstruct aspects of the district's social structure. Community formation and change are examined from the years of settlement, through the consolidation of family farming, to changes in the twentieth century. Today, despite the increasing importance of more centralised forms of economic and political control outside the district, community continues to exist on the basis of high levels of continuity, a clear sense of boundary and strong associational structure.

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  • Power system state estimation and probabilistic loadflow analysis.

    Brown, Ernest Paul Michael (1981)

    Doctoral thesis
    University of Canterbury Library

    This thesis investigates the treatment of aposteriori and apriori uncertainties in power system planning and operation. Aposteriori uncertainty is treated by power system state estimators. A survey of existing techniques and their limitations is described. A method is presented that improves the speed of weighted least squares state estimation by modifying the structure of injection measurements to give a very sparse information matrix, the matrix to be inverted. Used with fast decoupling, this approach yields a very fast on-line state estimator, capable of handling all types of measurements. Bad data detection and identification techniques are reviewed and an improvement based on "mathematical" bad data removal is presented. The inclusion of h.v.d.c. links into a.c. state estimation is considered. Decoupling and geographic partitioning of the multi a.c. -h.v.d.c. state estimator are shown to cause little degradation in the estimates, and a method of accurately representing commutation overlap angle is outlined. Availability analysis in state estimator operation and design is considered, and applied to optimal meter placement design. The feasibility of hierarchical central-electrical, local-dynamic hydroturbine and canal state estimation, based on a linearized Kalman filter, is investigated. Apriori uncertainty in long-term future planning studies involving expected nodal generation and loads can be included in stochastic loadflows. A method is presented which enables the stochastic loadflow, which handles only gaussian statistics, to handle non-gaussian probability distributions via gaussian sum approximations. H.v.d.c. links are also included in a.c. stochastic loadflows, using both correlated and uncorrelated data.

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  • Risk assessment methods in road network evaluation : a study of the impact of natural hazards on the Desert Road, New Zealand

    Dalziell, Erica (1988)

    Doctoral thesis
    University of Canterbury Library

    This study investigates hazards that have the potential to close the Desert Road, which is part of New Zealand's major north-south link, State Highway 1. It provides a case study for the application of risk assessment methodology to the evaluation of road networks. The hazards that are investigated include snow and ice conditions, volcanic eruptions and lahars, seismic events, and traffic accidents. All of these hazards have the potential to close the Desert Road. For each of the hazards, a stochastic model is developed to determine the probability of the hazard occurring and the resulting road closure duration. The vulnerability of alternative routes through the Central North Island to these hazards are also evaluated. A traffic assignment model, SATURN, is used to predict the disruption caused by closures of the Desert Road and its alternative routes, quantifying the economic cost of closures to the New Zealand economy. Monte Carlo simulation is then used to find the probability distribution of the average annual cost of closures due to each hazard. Mitigation options that may either reduce the probability of closure occurring, or reduce the duration of closures, are investigated. The new risk of closure with the mitigation in place is compared to the existing risk of closure, to find the probability distribution of the benefit-cost ratio for each mitigation. A computer based risk optimisation program is described that can help select the portfolio of mitigation options that will optimise the risk reduction attained for a given expenditure.

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  • Studies on vesicular-arbuscular mycorrhiza and fungal root pathogens of white clover and their interaction.

    Lim, Loon Lui (1983)

    Doctoral thesis
    University of Canterbury Library

    The role of a vesicular-arbuscular mycorrhizal fungus Glomus fasciculatus (Thaxter sensu Gerdemann) Gerdemann & Trappe in white clover (Trifolium repens L.) and its interaction with three fungal root pathogens Codinaea fertilis, Fusarium avenaceum (Fr.) Sacco. and Thielaviopsis basicola (Berk. & Br.) Ferraris was investigated. The growth responses of white clover to applied phosphorus and G. fasciculatus infection are shown in two P-deficient soils applied with a range of phosphorus levels. Growth was greatly stimulated by G. fasciculatus in both soils at all phosphorus levels, but the magnitude of the mycorrhizal response decreased with increasing phosphorus levels. Optical and transmission electron microscopes were first used to elucidate the mycorrhizal infection process and host response to infection. Some novel features including very thick-walled hyphae and intrahyphal hyphae within the host roots are recorded. C. fertilis, F. avenaceum and T. basicola were shown to be pathogenic on white clover, the infection and colonization of the roots being followed microscopically. The pathogens showed variable effects on plant yield under various experimental conditions of defoliation, plant age and inocula type. G. fasciculatus was shown to confer protection to white clover by reducing the detrimental effect of the pathogens under some conditions.

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  • Taxonomic investigation of elements from the early cretaceous megaflora from the Middle Clarence Valley, New Zealand

    Daniel, Ian L. (1989)

    Doctoral thesis
    University of Canterbury Library

    The fossil megaflora of the middle Clarence valley, South Island, New Zealand, contains leaf forms attributable to all the following plant groups: liverworts, ferns, equisetaleans, cycads, bennettites, pentoxylaleans, ginkgoaleans, araucariaceans, podocarps, pteridosperms and dicotyledons. The elements investigated here are taxa belonging to Phyllopteroides, Taeniopteris, Cycadales, Bennettitales, Ginkgo, Agathis and dicotyledonous foliage form species. The sediments in which this megaflora occurs are fluviatile and lacustrine and were laid down in a coastal region of South Gondwana. The age of the deposits is late Albian/early Cenomanian. The palaeolatitude was high, being within the Antarctic Circle. Palaeoclimatic evidence shows that the climate of polar regions in Cretaceous times was mild temperate and highly equable at least in coastal regions. Methods of extraction and photography of fossil cuticle are described. Numerical taxonomic methods are used to analyse 1) the relationships of fossil taxa within particular plant groups, 2) between New Zealand and Australian fossils, and, 3) between a fossil species and extant species of Agathis. The new term numerotype is here proposed to rationalise variation of characters within a taxon for computational purposes. Thirty-four new leaf form species are described systematically, of which 22 are dicotyledonous. These dicotyledonous leaves are all simple, broadly laminate, pinnately reticulate-veined and petiolate, and possibly some were deciduous.

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  • The glacial sequences in the Rangitata and Ashburton valleys, South Island, New Zealand

    Mabin, M.C.G. (1980)

    Doctoral thesis
    University of Canterbury Library

    Extensive areas of glacial, fluvioglacial and associated landforms and deposits are preserved in the Rangitata and Ashburton Valleys. Geomorphologic and lithostratigraphic maps of this area are presented. Three main glacial sequences are identified: those formed by the main lobe and distributary lobe of the Rangitata glacier, and that associated with the combined Rakaia distributary lobe and Cameron glaciers. The smaller Ashburton glacial sequence is also mapped. A sequence of five Late Pleistocene glacial advances representing at least three glaciations can be recognised as follows (from youngest to oldest): Spider Lakes/Lake Heron Advances minor interstadial Hakatere/Emily Advances major interstadial Trinity Advance interglacial Dogs Hill Advance interglacial Pyramid Advance Analysis of a large area of deglacial landforms, formed during the retreat of the distributary lobe of the Rangitata glacier after the Spider Lakes Advance, allows a detailed pattern of deglaciation to be determined. The fan surfaces of the southern part of the Canterbury Plains have also been studied to determine the relationship between them and the inland glacial sequences. Good correlations can be proposed between these glacial sequences and others in the Canterbury region.

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  • Studies on bud dormancy of woody species

    Lallu, Nagin (1982)

    Doctoral thesis
    University of Canterbury Library

    The role of endogenous inhibitors and growth substances in the regulation of bud dormancy of wood plants was investigated using mature trees, seedlings, isolated shoots, and aseptically cultured buds and shoots. The photoperiodic induction of dormancy was not mediated through changes in inhibitor β activity, or ABA levels of buds and leaves of Alnus viridis seedlings. Changes in the activity of the inhibitor β fraction of buds and leaves of field grown Alnus glutinosa occurred during autumn but were not correlated with the onset of dormancy. Exogenous applications of 10-4M ABA, 10-3M CCC, ABA + CCC, 10-3M C5, 10-3M C9 and 10-3M C10 to actively growing Alnus viridis seedlings did not result in the formation of dormant buds. Dormancy was not induced by pruning the root system of actively growing alder seedlings or by the treatment of isolated growing shoots with 10-4M ABA. ABA prolonged the dormancy of apparently dormant buds after their transfer to an environment favouring growth, but this effect was modified by species, time of year, presence and absence of leaves, and position of the bud on the stem. C8 and C9 prolonged the dormancy of Populus nigra Italica while C10 promoted bud burst in Salix alba/babylonica. CCC was ineffective in most species tested (Alnus, Populus and Salix) except when in combination with ABA. The use of aseptic shoots of Populus yunnanensis cultured in vitro as a bioassay for dormancy-inducing substances was found to be limited by the variable growth responses elicited. No dormancy-inducing substances were detected in extracts, including the inhibitor β fraction, of dormant buds or leaves or shoots. The presence of various concentrations of ABA, C5, C10, AMO 1618 and ABA + AMO 1618 in the medium did not cause the formation of dormant shoot morphology, although growth was inhibited by certain treatments. Results are discussed in relation to the inhibitor hypothesis of dormancy regulation.

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  • Scaled-down modelling and microprocessor facilities for the simulation and assessment on HVDC convertor disturbances.

    Hisha, Horoshi (1983)

    Doctoral thesis
    University of Canterbury Library

    Aimed at the eventual implementation of direct digital control and protection in a.c./d.c. power systems, this thesis describes the design of a thyristor convertor model and an interrupt-driven multiple microprocessor system capable of simulating various faults encountered in real systems, and of monitoring the normal and abnormal convertor operating states in real time. Recent developments of HVDC convertor control and operation are first reviewed, and a fast and reliable method of deriving convertor-valve ON/OFF states is practically implemented in the model and assessed for other applications. A comprehensive set of normal and abnormal convertor waveforms is derived and used as a basis for the software-based fault simulation and fault-data acquisition scheme. The proposed scheme takes full advantage of the versatile and cost-effective general-purpose microprocessor to provide sophisticated convertor operating-state monitoring, fault data recording and immediate display on the inter-connected VDU terminal. In conjunction with the fault simulation scheme, the conditions for fast shut-down of the convertor upon the occurrence of certain disturbances are investigated.

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