14,602 results for Doctoral

  • Saturated pool boiling and subcooled flow boiling of mixtures at atmospheric pressure

    Wenzel, Ulrich. (1992)

    Doctoral thesis
    The University of Auckland Library

    An experimental and theoretical investigation of heat transfer to liquid mixtures has been performed using binary and ternary mixtures of acetone, isopropanol and water. Two data-bases were established which contain measurements of the heat transfer coefficient under saturated pool boiling and subcooled flow boiling conditions. A third database comprises measurements of heat transfer and pressure drop in a plate heat exchanger. The performance of two heat transfer enhancement techniques, namely the coating of the heat transfer surface with teflon and a perforated brass foil, was studied under saturated pool boiling conditions. A model was developed, which can be used to predict the heat transfer coefficient. The model is based on the additive superposition of convective and boiling heat transfer coefficients. It is applicable for heat transfer to mixtures and single component fluids under saturated and subcooled boiling conditions. The empirical parameters in the correlations used in the model were not altered to fit the measurements of this study. The predictions of the model were compared to the experimental data, which covers the convective heat transfer regime, the transition region and the fully developed nucleate boiling regime. It was found that the best agreement between predicted an measured values was achieved, if the linear mixing law was used to calculate the ideal heat transfer coefficient rather than the correlations by Stephan-Preußer or Stephan-Abdelsalam. The heat transfer coefficient under saturated pool boiling conditions could be predicted with an accuracy of 12.6 %. A comparison between over 2000 measured heat transfer coefficients under subcooled flow boiling conditions in an annulus and the predictions of the model showed good agreement with a mean error of 10.3 %. The accuracy of the model was found to be independent of the fluid velocity and composition, as well as of the magnitude and mechanism of heat transfer. The heat flux in a plate heat exchanger could be predicted with a mean error of 6.9 % for a wide range of fluid velocities, subcoolings and compositions. The heat transfer coefficient on the test liquid side of the exchanger could be predicted with a mean error of 10 %. The heat transfer model was used for a theoretical study of the heat transfer to mixtures boiling on a finned surface. It was found that the fin geometry and thermal conductivity have a distinct influence on the local and mean heat transfer coefficients. The results indicate that the application of fins is more effective for boiling of mixtures than for boiling of single component liquids.

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  • Rearrangements of N-Halogenoamides

    Judd, William Paul (1967)

    Doctoral thesis
    The University of Auckland Library

    Part I, The Hofmann Rearrangement. First-order rate constants and activation parameters were determined for the rearrangement of eleven N-halogenoamides. The structures of the N-halogenoamides (RCO.NHX) differed in the leaving group (X = chlorine or bromine) and the migrating group (R=ethyl, isopropyl, t-butyl, diphenylmethyl, benzyl, phenyl or p-tolyl). N-Bromoamides and the corresponding N-chloroamides rearranged at similar rates. When the leaving group was changed from bromide to chloride the activation energy was reduced by about one kcal. mole-1 and the activation entropy was reduced by about three cal. deg.-1 mole-1. Differences in the reactivity of halides as leaving groups from carbon and nitrogen are discussed. Changes in the structure of alkyl migrating groups resulted in small irregular changes in the activation parameters. The kinetic data were consistent with a stepwise rearrangement mechanism in which halide departed from nitrogen in the rate-determining step to give a short-lived nitrene intermediate which subsequently rearranged to an isocyanate. Other aspects of the Hofmann rearrangement were investigated. In the Hofmann reaction of amides and hypobromite, N-bromination of the amide was found to be much faster than the rearrangement of the intermediate N-bromoamide conjugate base. In contrast, when amides and hypochlorite reacted in alkaline solution N-chlorination was not fast by comparison with the rearrangement of the intermediate N-chloroamide conjugate base. Oxygen, iodide, and hypobromite did not inhibit the Hofmann rearrangement. Rearrangement of N-brmoacetamide N-bromopropionamide, N-bromoisobutyramide and N-bromopivalamide in the presence of oxygen gave traces of nitrite as a by-product. Nitrite may result from the capture of an intermediate nitrene by oxygen. Ionisation constants of six N-bromoamides and one N-chloroamide were measured. Of the N-halogenoemides which were investigated, the most acidic was N-chloroperfluorobutyramide (pK 2.45) and the least acidic was N-bromopropionamide (pK 7.95). There are no ionisation constants of N-halogenomides recorded in the chemical literature. Part II, The Rearrangement of N-Bromo-α-halogenamides and N-Bromoperhalogenoamides. Previous investigators of the rearrangement concluded that the conjugate base of the N-halogenoamide rearranged intramolecularly via a cyclic four-membered transition state to give an alkyl halide and cyanate ion. This mechanism is incompatible with evidence presented in this thesis. The arrangements of N-bromoperfluorobutyramide and N-bromo-α-chloroisobutyramide in alkaline solution were not first-order reactions. In neutral aqueous solution, the N-halogenoamide conjugate bases did not rearrange. However, in the presence of an excess of hydroxide ion, the N-halogenoamide rearranged readily. The rearrangement was catalysed by hydroxide ion and ammonia and inhibited by many reagents including oxygen, hypobromite, iodide, cupric hydroxide, silver oxide, and amides of carboxylic and sulphonic acids. Possible rearrangement mechanisms are discussed. The effects of small proportions of the inhibitors showed that the rearrangement was a chain reaction. Two probable steps in the chain reaction are the addition of hydroxide ion to the N-halogenoamide conjugate base to give a dianionic intermediate and heterolysis of the nitrogen-bromine bond in this intermediate to give a nitrene. Part III, The Reaction of Mandelamide and Hypohalite. In alkaline solution, mandelamide and hypohalite yield benzaldehyde, cyanate and halide. Several mechanisms which were postulated by previous investigators are excluded by evidence presented in this thesis. Evidence for an N-chloromandelamide intermediate in the reaction of mandelamide and hypochlorite was obtained. Chlorination of mandelamide in neutral or acidic solution gave N-chloromandelamide and N,N-dichloromandelmide. In alkaline solution, the N-chloromandelamides decomposed to give benzaldehyde and cyanate. This reaction was much faster than the reaction of mandelamide and hypochlorite to give the same products. The reactions of hypobromite and hypoiodite with mandelamide were also investigated. Neither oxygen nor an excess of hypobromite inhibited the reaction of mandelamide and hypobromite to give benzaldehyde and cyanate. Hypoiodite (prepared from the reaction of hypochlorite and iodide) and mandelamide also gave benzaldehyde and cyanate in high yield. The mechanism most consistent with the evidence involves the rearrangement of an intermediate N-halogeno-α-hydroxyamide conjugate base to an α-hydroxyalkyl isocyanate which subsequently decomposes to benzaldehyde and cyanate. Mechanisms involving dianionic intermediates were disproved. Stoichiometric similarities in the rearrangements of N-bromo-α-halogenoamides and N-halogeno-α-hydroxyamides were shown to be fortuitous and not the result of similarities in the rearrangement mechanisms. Part IV, Preparation of Amides, N-Bromoamides, and N-Chloroamides. Preparations of amides and N-halogenoamides used in this thesis are described. Some of the N-halogenoamides have not been reported previously. Methods for preparing N-bromo-perhalogenoamides which are described in the chemical literature involve the bromination of the silver salt of the perhalogenoamides in trifluoroacetic acid solution. A much simpler method for preparing N-halogenoperhalogenoamides is described in this thesis.

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  • Economy, ritual and history in a Balinese tourist town

    MacRae, Graeme S. (1997)

    Doctoral thesis
    The University of Auckland Library

    This work began in reflection upon the form of tourism in Ubud: in which rapid economic change and profound cultural conservatism appear combined in unlikely symbiotic relationship. It became, in the field, a set of parallel enquiries into tourism, economics, politics, ritual, spatial organisation and history linking Ubud with wider local, regional and global processes. My provisional argument goes something like this. The economic development associated with tourism has resulted in Ubud not in a wholesale replacement of the forms of traditional culture with those of international capitalist culture but instead with conservation, development and intensification of aspects of traditional culture. Tourism is in fact built upon the marketing of an image of traditional culture consisting primarily of the performing and plastic arts and an aesthetic of village life combining agricultural production and ritual activity. In practice tourism has transformed the economic foundations of this way of life from dependence upon agricultural production to dependence upon a whole new sector providing goods and services to tourists. This transformation has had varied effects upon the components of the marketing image. One the one hand it has made possible profitable commoditisation of traditional arts but on the other it has marginalised the agricultural sector in a number of ways. The relationship between tourism and ritual activity is less direct. While people have resisted direct commodification of ritual, they recognise its role as a tourist attraction. Ritual practices and the temples in which they take place have however been the subject of massive redevelopment. While the forms of these are traditional, their content is linked to tourism in more complex ways. This process has not been ad-hoc but has been the subject of de-facto management by various parties including the traditional aristocracy, foreign expatriates, government and an emerging middle class. This management has been enabled and limited by access of the various parties to key resources including English language, land, cultural knowledge, investment capital and government contacts. This thesis does not report on all of this but represents in effect a report upon work in progress, providing a broad overview and the first stage of what is now seen as an ongoing research project. It is presented as a series of linked sections designed to be read at three levels: 1. as stand-alone contributions to various sub-fields of Bali studies, 2. as a set of relationships between these sections which contribute to the argument outlined above and 3. as the outline of a larger research project linking Ubud into processes of wider geographical compass and historical depth. It begins with description of contemporary Ubud, the transformation of its economy and a brief history of tourism. The relationship between ritual and economy is discussed both in general terms and ethnographic detail to provide insight into the context of cultural ideas in which tourist development has taken place. The spatial organisation of ritual reveals patterns of cultural order and political influence requiring historical analysis which in turn focuses attention on the role of the traditional aristocracy and changing patterns of control over land and labour as key factors in understanding the contemporary situation. Keywords: anthropology, Bali, economy, history, Indonesia, ritual, tourism

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  • The earthquake stability of earth structures

    O'Halloran, M. (1983)

    Doctoral thesis
    The University of Auckland Library

    The main aim of this study is to develop a practicable computer method for analysis of the dynamic response of a two dimensional soil structure, which takes into account the generation of excess pore pressures and can predict final deformations. A secondary aim is to investigate the dynamic behaviour of a silt and the effect of variations in the stress-controlled dynamic triaxial test method on the measured sample response. The soil model employed in the developed method of dynamic analysis uses a set of nested yield surfaces to represent shear stress-strain behaviour. These yield surfaces are defined by von Mises failure criterion, have an associated flow rule and undergo both kinematic and isotropic hardening. An empirical model is used to calculate the rise in pore pressure due to cyclic shear stresses. The changes in yield surface radii and hardening constants are defined by experimentally determined relationships between maximum shear modulus, shear strength and mean effective confining stress. A combination of critical state soil mechanics and volumetric considerations is used to relate increments in mean strain to increments in mean stress. The soil structure is divided into elements and a finite difference scheme used to solve the equations of motion. An energy transmitting boundary is incorporated in the analysis. The program has the capacity to analyse the dynamic response of a soil structure to both shear and compression waves approaching the base of the structure from any angle. The dam constructed for the Patea hydroelectric scheme was used as a practical application of the computer program. An input earthquake record considered appropriate to the site was chosen. The dynamic analysis of the dam with an empty reservoir indicated that in this state the dam can satisfactorily withstand the design earthquake. The dynamic analysis of the dam with a full reservoir subject to the same uniform base excitation suggests that a slide in the downstream shoulder would develop. The input earthquake waves travelling along the base of the dam from the upstream toe to the downstream toe, accentuate these displacements. These displacements are caused by the generation of high pore pressures which redistribute after the earthquake to temporarily reduce the stability of the dam further. The assumptions and approximations inherent in the method of analysis tend to make the results pessimistic. It was found that the vertical component of earthquake excitation was the major cause of the generated pore pressure. The results of an extensive programme of laboratory tests carried out on the main construction material in the dam, are presented. The test programme consisted of undrained triaxial, isotropic consolidation, free vibration torsion and stress controlled dynamic triaxial tests. Factors influencing the pore pressure generation characteristics obtained from the stress-controlled dynamic triaxial tests, were found to include the compacted dry density, the cyclic shear stress, the initial effective confining stress, the test frequency, the method of sample compaction, the use of filter paper side drains and the type of end platen.

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  • Demography and life history characteristics of the New Zealand geoduck, Panopea zelandica

    Gribben, Paul Edward (2003)

    Doctoral thesis
    The University of Auckland Library

    This thesis provides information on the demography, population dynamics and life history characteristics of the New Zealand geoduck, Panopea zelandica (Quoy and Gaimard, 1835), from Wellington Harbour and Kennedy Bay on the Coromandel Peninisula. The distribution, abundance and habitat characteristics were determined for both populations and estimates of age, growth and mortality were also investigated. Reproduction, sexual development, fertilization kinetics and larval development of P. zelandica are also described. These studies provide a preliminary assessment of the effects that harvesting may have on the sustainability of populations of P. zelandica, and the potential for developing aquaculture industries for this species. Geoducks in Kennedy Bay were found from 4-8 m water depth, and from 4-16 m in several beds in Wellington Harbour. In Wellington Harbour, there was a pattern of increasing numbers with depth up to~15 m (Fig. 2.2). Numbers decreased thereafter. Analysis of sediment samples indicated that P. zelandica was more prevalent in fine sand to fine silty sand substrata, with reduced numbers in siltier sediments. The water depths and sediment characteristics presented for the populations considered appear to be general habitat characteristics for this species. This will aid in finding further populations and in establishing ongrowing methods for this species. Experiments indicated that counts of siphon holes could be quickly and reliably used to provide estimates of abundance. Results also suggest that a show-factor of ~0.90 may be applicable to abundance estimates of other P. zelandica populations, and can be used year round. Estimates of density for P. zelandica in several bays in Wellington Harbour (0.14 to 0.49 geoducks.m-2) and Kennedy Bay (0.058 geoduck.m-2) were very low. P. zelandica is also very long lived (up to 86 years) and populations had low estimates of natural mortality (s may be of use to marine farmers wanting a quick and easy method for assessing the reproductive state of potential broodstock. Patterns of sexual maturity were equivalent for both populations with 50% maturity calculated to be at ~55 mm and ~57 mm at Shelly Bay and Kennedy Bay, respectively. Samples of geoducks collected from June 1999 to March 2001 determined that reproductive development was protandric, as all immature geoducks from a single cohort collected over the sampling period matured into males in their third year of life. Females became more prevalent as size and age increased. Sex ratios with age were equal in the larger size classes. However, females dominated the larger size classes with respect to size. Thus harvesting may potentially target female geoducks. However, the relationship between siphon hole size and shell length was not strong (r=0.57). In terms of aquaculture, ripe broodstock were easily spawned, and resultant larvae grown through to settlement (which occurred spontaneously after l6 days at a size of ~270 μm) indicating that this species may be amenable to hatchery culture. Optimal fertilisation was achieved at concentrations around 2x102-103 sperm/μl over a range of contact times with the proportion of monospermic zygotes decreasing rapidly at higher sperm concentrations. An increase in gamete age from 0 to 30 mins adversely affected the fertilisation success of P. zelandica. Photomicrographs of developing larvae indicated an absence of fully developed ctendia and siphons in settling larvae, similar to the pattern described for the North American geoduck, Panope abrupta. Measurements of shell morphology were found to be adequate descriptors of larval development. SEM indicated that the provinculum of straight hinge and developing veliger larvae lacked any teeth, although there was some development of a small lamelliform tooth on the hinge structure of newly settled larvae. Prominent spines common on dissoconch shells of other hiatellid clams were absent in newly settled post-larvae of P. zelandica. These descriptions provide vital information for identifying larvae and newly settled recruits in plankton and sediment samples and will aid in determining patterns of recruitment, vital for assessing the sustainability of natural populations. The life-history characteristics and population characteristics described in this thesis for P. zelandica raise serious concerns regarding the sustainability of harvesting this species. However, the ease with which ripe P. zelandica could be spawned, and the resultant larvae grown through to settlement, suggests that the aquaculture of this species warrants further investigation.

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  • The Karikari plutonics of Northland, New Zealand: the petrology of an arc-type intrusion and its envelope

    Ruddock, Richard Sean (1990)

    Doctoral thesis
    The University of Auckland Library

    The Karikari Plutonics are Early Miocene in age and consist of two plutonic bodies, with age relations delineated by cross- cutting relationships, and associated later stage dykes. The older pluton is a complex body exhibiting textural variability, cumulate-style crystallisation, varied enclaves (indicating complex magma chamber processes including convection and crystallisation along steeply-dipping northwest oriented fronts) and a multi-phase structural and dyke intrusion history. Modal analysis shows this body to be diorite to quartz monzodiorite, and geochemically calc-alkaline and medium-K in nature. In contrast the younger pluton is extremely homogeneous and intruded by a single, volumetrically sparse, dyke phase. Modally quartz monzonite to granite (adamellite), and high-K calc- alkaline, this body has higher Si, K-group + Na, REE group and HFSE group elements than the older pluton. Mineral differences are confined to An contents in plagioclase, En values in orthopyroxenes and a wider range of Al in younger pluton hornblendes. Igneous differentiation can be modelled within the older pluton and between the older and younger bodies, by fractional crystallisation dominated by plagioclase, with subordinate ortho- and clino- pyroxene and oxide phases. The dykes show a compositional range from basaltic andesite to dacite, with andesite volumetrically dominant. A temporal trend can be seen with younger dykes becoming more felsic and of greater volume, and changing orientation from northeast to northwest. Two subdivisions can be made based on the presence or absence of hornblende. Pyroxene only dykes are mostly medium-K and dominantly andesitic, whereas hornblende-bearing lithologies are both medium-K and high-K, are andesite and dacite, and appear to be more evolved chemically. The rock envelope into which the Karikari Plutonics was intruded consists of Cretaceousage basalts, rhyolites and sedimentary lithologies. Although a regular contact aureole is not exposed, the lowest grade of contact metamorphism is delineated by the first occurrence of biotite. Rocks equivalent to the hornblende hornfels facies are widespread and rare pyroxene hornfels are found adjacent to contacts. Alteration and veining, particularly prevalent in fault/shear zones, and the presence of a magmatic-hydrothermal type breccia are evidence for a hydrothermal system associated with the waning stages of Lower Miocene-age igneous activity on the Karikari Peninsula. Fluid inclusion and stable isotope data indicates the presence of fluids of both magmatic and meteoric origin. The Karikari Plutonics are correlated with the arc-type regional association of Northland and the Coromandel Peninsula. The source of these rocks is broadly M-type, hydrous and involving subduction zone, and modified mantle wedge components, but with some unspecified crustal involvement indicated by Sr isotopes. Specifically this source is modelled, for the Karikari Plutonics, as having LREE enriched 2x relative to HREE and partially melting (< 15% of the source) at the base of the crust (≥30 km). These melts gave rise to the arc-type association either erupting at the surface, or ponding in upper crustal (≤10 km) magma chambers.

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  • Non-commensurate realization of compact broadband R.F. Circuits

    Blomfield, Douglas Arthur Edmonds (1983)

    Doctoral thesis
    The University of Auckland Library

    A new method for the synthesis of broadband impedance transformers having predictable passband frequency response is presented. The technique is based on the use of non-commensurate (i.e. unequal element length) transmission line networks. Through the use of approximations and computer optimization studies non-commensurate circuits are shown to be advantageous in distributed circuit design. The new method derives a non-commensurate circuit from a conventional commensurate prototype in such a way that the transmission matrix of pairs of elements in both circuits is made equal at one frequency. The transformation used ensures that the frequency response of the derived circuit closely matches that of the prototype circuit. Limitations on section characteristic impedances imposed either by constructional constraints or other practical realizability considerations are more easily met using the new design technique than when using conventional commensurate networks alone, Moreover, wide harmonically related passbands are largely avoided. The method finds greatest application where there are circuit length (or size) restrictions which must be met. Where such restrictions do not apply, conventional commensurate techniques are usually sufficiently flexible. The non-commensurate technique can however still provide benefits of even greater flexibility or better stop-band attenuation. The method presented is only an approximate equivalence and so an analysis of the technique is presented. The analysis establishes the degree of approximation. The use and application of the non-commensurate design technique are supported by an experimental investigation.

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  • Ethylene Biosynthetic Genes in Actinidia Chinensis

    Whittaker, David J. (1997)

    Doctoral thesis
    The University of Auckland Library

    Appendix 1 restricted at the request of the author Actinidia chinensis, a diploid relative of kiwifruit, has valuable fruit characteristics, and varieties with superior flavour and marketable size have recently been selected in a classical breeding programme. However, the marketability of the fruit of A. chinensis and many other species of Actinidia is limited by poor fruit storage properties. Pioneering work in tomato has demonstrated that fruit ripening and senescence can be very effectively delayed by down-regulating genes required for biosynthesis of the phytohormone ethylene. The goal of this work was to isolate genes for ethylene biosynthesis in A. chinensis, characterise their expression, and to generate transgenic plants containing T-DNA constructs designed for ethylene downregulation. A small cDNA library was constructed from RNA isolated from the ripe fruit of A. chinensis. The library was screened for genes encoding each of the enzymes in the ethylene biosynthetic pathway, by probing with PCR products amplified from kiwifruit cDNA and with a cDNA clone previously isolated from kiwifruit. Three distinct cDNA clones encoding S-adenosyl-L-methionine (SAM) synthetase (ACSAM1, ACSAM2 and ACSAM3) were isolated from the library, together with two distinct 1-aminocyclopropane-1-carboxylic acid (ACC) oxidase cDNA clones (ACAO1 and ACAO2). No ACC synthase cDNAs were detected in the library, indicating low transcript abundance. However, a partial ACC synthase cDNA (ACAS1) was amplified from ripe fruit using PCR techniques, and subsequently cloned in a plasmid vector. Phylogenetic analysis of SAM synthetase protein sequences from A. chinensis and other plant species indicates bifurcation of angiosperm SAM synthetase sequences into two main branches; ACSAM3 was assigned to a different branch from ACSAM1 and ACSAM2. The peptide sequence of ACAS1 shows higher homology to several auxin-inducible ACC synthase peptides than the product of the ethylene-inducible ACC synthase gene which is predominantly transcribed in ripening tomato fruit. RNAse protection assays were employed to estimate the relative transcript levels of each of the ethylene biosynthetic genes isolated from A. chinensis during ethylene-induced, post-harvest fruit ripening, and in immature fruit and floral samples. The response of the mature fruit to exogenous ethylene indicated a clear separation of ethylene sensitivity and ethylene production in A. chinensis. The application of exogenous ethylene correlated with increased transcript levels for all three SAM synthetase genes (ACSAM1, ACSAM2 and ACSAM3) and for the ACC oxidase gene family. Transcription of the ACC synthase gene ACAS1 was not affected by exogenous ethylene, but transcript levels increased during subsequent ethylene biosynthesis, consistent with this being a controlling step for the onset of ethylene production. One or more ACC oxidase transcripts increased significantly both prior to and during ethylene production. Only one of the SAM synthetase transcripts (ACSAM3) was induced during the late ethylene burst, and these transcripts were also abundant in floral tissues and young fruit. A role for SAM synthetase genes in the methionine salvage pathway is discussed. The expression patterns for ACAS1 and the ACC oxidase gene family arc consistent with the consensus view that the rate of ethylene biosynthesis in plant tissues is dependent on both ACC synthase and ACC oxidase activity levels. Therefore, with the aim of down-regulating ethylene biosynthesis in A. chinensis, expression cassettes containing ACAS1 and ACAO1 cDNAs, each controlled by a d35S promoter, were inserted in tandem into the Agrobacterium binary vector pCGN1549, in both the sense and antisense orientations. Leaf tissue from the ‘Earligold’ variety of A. chinensis was transformed with the resulting binary vectors, and transgenic plants were regenerated. PCR and Southern analysis indicated intact T-DNAs were integrated in at least half of the transformed plants, and Northern analysis detected mRNAs from one of the transgenes transcribed from both the sense and antisense constructs. No decrease in wound-induced ethylene biosynthesis was detected in the leaves of a small sample of these transgenic plants, and a larger number of transformants are now being grown for phenotypic screening. Down-regulation of ethylene biosynthesis may improve the storage properties and/or the shelf life of transgenic A. chinensis plants and may provide insights into the roles of ethylene in fruit ripening.

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  • Studies of dichloro- and tetrachloro- adducts of naphthalene and some of its substituted derivatives

    Burton, Graham William (1973)

    Doctoral thesis
    The University of Auckland Library

    trans-1,2-Dichloro-1,2-dihydronaphthalene has been obtained as the major product of the photochlorination of naphthalene at low temperature, and is the first authentically described naphthalene dichloride. Its further reaction with chlorine, under heterolytic conditions gives, in part, a new naphthalene tetrachloride, whose configuration has been assigned, by 1H n.m.r., as being that of the r-1,c-2,c-3,t-4-isomer. The assigned configuration and conformation of the compound are confirmed by its behaviour on alkaline dehydrochlorination, which gives mainly trans-1,2,4-trichloro-1,2-dihydronaphthalene as an intermediate. The naphthalene dichloride, and its 4-chloro-derivative, have been found to undergo solvolysis in methanol - acetone (4:1), and it is further found that heterolysis of the carbon-chlorine bond at C- 2 is strongly favoured, leading largely to the 1-chloro-substituted elimination product. The former dichloride also gives a small amount of 1-methoxynaphthalene, which is possibly derived by unimolecular substitution at the 1-position. The presence of a chlorine atom at the 3-position of the structure is found to inhibit the solvolytic reaction. Bimolecular syn-elimination in these compounds is accelerated by the presence of additional chlorine substituents, and the increasing preference shown for attack at H- 2, which is further accentuated by the use of the powerfully basic reagent, potassium t-butoxide in t-butanol-dimethylsulphoxide (1:4), is interpreted as indicating a transition state tending toward the E1cB- like side of the E2 spectrum of transition states. The naphthalene tetrachlorides, and some derivatives, have been found to undergo aluminium trichloride-catalysed epimerization at the benzylic centres, which yields information on the relative thermodynamic stabilities of isomers with identical relative configurations at C- 2 and C- 3, and can also be of synthetic value. The photochlorination of 1-chloronaphthalene in CC14 at room temperature proceeds analogously with the reaction of naphthalene under the same conditions, giving five new tetrachlorides, four of which have been thoroughly characterized. The presence, in some tetrachlorides, of inter-ring non-bonded compressions between adjacent chlorines has been found to cause significant changes in the geometry of the alicylic ring, causing a tendency for the half-boat conformation to be adopted, provided this does not lead to 1,4-diaxially related chlorines. The strain present in these compounds is manifested by their very marked tendency to undergo isomerization in the presence of aluminium trichloride, and greatly increased rates of alkaline dehydrochlorination. The chlorination of l,5-dichloronaphthalene in chloroform, or dichloromethane, has been studied and has been found to be markedly catalysed by traces of iodine. The products are almost wholly derived by addition of chlorine in the first stage, and this has been interpreted as arising from a steric inhibition of proton-loss by the adjacent peri-chlorine.

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  • Emotional child abuse and resiliency: an Aotearoa/New Zealand study

    McDowell, Heather (1995)

    Doctoral thesis
    The University of Auckland Library

    Emotional child abuse is recognised as the unifying construct of child abuse (Brassard & Gelardo, 1987). Defining emotional child abuse (ECA) is an area of debate in the literature and a widely recognised definition has yet to be developed. There is general agreement on the definition of resilience with most making reference to adapting and coping well in the face of adversity. Recent research has questioned the implied unidimensionality of the term. A research study was designed with several aims: to explore how ECA is defined by professionals working in the area of child abuse, and by members of the general public; to develop an understanding of the nature of ECA from adults who self-identified as having experienced ECA; and, to examine the ways in which these adults coped, and dealt with ECA and its effects. Further aims of the research following from these were to develop a definition of ECA, and to identify implications for practice for those working in the area of ECA. Attachment theory (Bowlby, 1969, 1988; Crittenden & Ainsworth, 1989) was the theoretical base for the research. The literature on resilience was reviewed with a particular focus on ECA. Consistent findings in the literature on the cost of resiliency in the area of emotional well-being and functioning were explored and used to critically examine the clinical utility of the term. Two surveys were developed, one for distribution to all the professionals working in the area of child abuse in statutory agencies in Auckland; and one for distribution to a sample of adults living in the greater Auckland area. Comparison of the conceptual and specific categories derived from the definitions of ECA provided by the professional group (N=l8l) and the lay group (N=142) indicated considerable agreement. Differences between the groups on the relative frequency of use of the categories were explained and directions for future research were suggested. Concurrence between the findings of this study and others on developing a definition of ECA supported the existence of ECA as a separate and consistent form of child maltreatment. Adults who saw themselves as having experienced ECA were identified through the general public and professional surveys (N=30). They were individually interviewed using a semi-structured format about the nature of the ECA they had experienced and how they had coped with it as a child, adolescent, and adult. The interviews, and relevant material from the surveys, were analysed using a Grounded Theory approach. The themes that emerged from the material on the nature of ECA were grouped into four areas: the nature of ECA; the effects of ECA; the context of ECA; and, disclosure of ECA. The themes that emerged on how participants coped and dealt with the ECA they had experienced revealed a range of coping strategies and changes in these across the broad developmental stages of childhood, adolescence, and adulthood. An important distinction that emerged was that between coping with the ECA and dealing with it. The cost of coping was a prominent theme and concurred with findings in the literature. The implications for practice and directions for future research generated by these findings are discussed. A theoretical definition developed from the research findings is presented and applied to specific examples from the research.

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  • Spread spectrum switching: a low noise modulation technique for PWM inverter drives

    Handley, P. G. (1990)

    Doctoral thesis
    The University of Auckland Library

    Three phase AC drives controlling cage induction motors have become widely accepted in industry, but one extant problem with this technology is that of increased acoustic noise emitted from the driven motor. This Thesis addresses the problem of the acoustic noise emitted from motors driven from voltage sourced PWM inverters and proposes a technique - Spread Spectrum Switching - for minimizing its effects. In the course of the work many other issues associated with real-time microprocessor-based PWM have also been advanced: • efficient microprocessor based PWM waveform generation, • harmonic analysis of generalized PWM waveforms, • compensation for the effects of power switch timing delays, and • compensation for the finite resolution of timers. The Thesis uses a variety of computational and analytical methods, backed by experimental observations, to quantify the improvement gained in each of these areas. Spread spectrum switching is a technique for eliminating the characteristically tonal structure of the acoustic noise emitted from a PWM inverter driven motor. Similar to the concept of spread spectrum communications, spread spectrum switching involves pseudo-randomly varying the instantaneous PWM switching frequency so that the energy of any PWM switching harmonics is dispersed over a wide bandwidth. This energy dispersion effectively eliminates any tonal components from the resultant motor acoustic noise while leaving the overall sound level largely unchanged; spread spectrum switching provides a significant qualitative yet minimal quantitative noise reduction. The PWM generation paradigm used in this Thesis is the recently reported Space Vector Modulation. A novel algorithm for microprocessor based space vector PWM generation is proposed, providing a basis for fast, efficient generation, even when overmodulating - a situation where many algorithms operate significantly more slowly. Furthermore, it is shown that the space vector method inherently generates a near optimum - in terms of motor harmonic loss - PWM waveform. However, when physically realized on a practical inverter such ideal PWM waveform s are corrupted by timing errors associated with both the inverter's power switches, predominantly the lockout time, and the finite resolution of hardware timers. Resolution corrected modulation is proposed for overcoming the problem of finite timer resolution and involves the use of integral feedback to account for any errors between ideal and physically realizable PWM switching times. This technique effectively provides 4 to 5 bits of added resolution to a given timer, allowing accurate waveform generation at low sinewave amplitudes and high switching frequencies using readily available, often microprocessor based, timers. Lockout times cause inverter output voltage errors, with consequent current zero crossing distortion, and a strategy for alleviating this problem is proposed and implemented in both a triangulation and space vector modulator. Two harmonic analysis techniques are proposed for analyzing PWM waveforms. The first technique is suitable for the analysis of regularly sampled PWM waveforms and has been used here to obtain closed form expressions for the harmonics of both space vector and asymmetrical triangulation PWM. These expressions show that PWM harmonics occur as a series of "combs" centered on multiples of the switching frequency. A second technique - the Directional Rotational Transform - is proposed for numerical analysis of general PWM waveforms. This technique uses an equivalent space vector representation of the PWM waveform, yielding the magnitude, phase and sequence (positive or negative) of the harmonics, and is useful in situations where each of the three phase waveforms is different, as in these cases Fourier Transform analysis of a single phase or line voltage only approximates the harmonics actually seen by the motor. The spectra generated using both these techniques compare favourably with those measured experimentally and, for synchronous PWM, those evaluated from Fourier Transforms. The culmination of modulation techniques presented in this Thesis yields a microprocessor based AC inverter drive featuring low acoustic noise emission at but a few kiloHertz switching rates and accurate PWM waveform generation using a single chip, low cost, micro-controller.

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  • Application of computational fluid dynamics to two-dimensional downwind sail flows

    Collie, Stephen (2006)

    Doctoral thesis
    The University of Auckland Library

    The research detailed in this thesis investigates the practical application of Computational Fluid Dynamics (CFD) to downwind sail design. Simulations were performed using CFX-5, an unstructured commercial CFD package. The research focuses on the performance of the SST and k-ω turbulence models which were judged to be CFX-5's most appropriate turbulence models for downwind sail flows. Two-equation turbulence models are viewed as the most appropriate model type for sail simulations, they capture a significant amount of the flow physics whilst providing turnaround times for sail simulations of less than one day. CFD simulations were compared with experimental data for a flat plate at shallow angles of incidence. This test case holds particular relevance to sail flows since both flows are affected by leading edge separation bubbles which form due to knife-edge separation at sharp leading edges. The CFD captures this leading edge bubble well, with the SST model predicting the length of the bubble with 7% of the experimental value. Wind tunnel data was gathered for two-dimensional downwind sail sections for the purpose of CFD validation. A preliminary wind tunnel study was carried out using a low aspect ratio model. The tests were prone to three-dimensional effects and only three-dimensional CFD simulations were capable of successfully reproducing the flow. High aspect ratio wind tunnel test results were also conducted in an effort to obtain nominally two-dimensional wind tunnel data. Surface pressures were measured using Pressure Sensitive Paint (PSP), however due to the low dynamic pressure of the tests error appeared in the data and comparison with the CFD was poor Results show that CFD is capable of qualitatively reproducing downwind sail flows, the leading and trailing edge separation regions were captured and the CFD results compared well with wind tunnel flow visualization. Finally, CFD simulations were used to investigate the two-dimensional downwind sail design space through a parametric study of sail draft and camber. Results show that increasing camber increases both lift and drag a trend that also is evident in three-dimensional sail designs. It is also shown that gains can be made by using designs with draft values as far aft as 60% which helps reduce the extent of trailing edge separation. This parametric design study illustrates how CFD can be used successfully to analyse design trends and rank designs. The research presented illustrates how CFD can be used in the design process but also that care must be made in validating the method. Through this study the relative strengths and weaknesses of the turbulence models are better understood. Whilst CFD cannot yet be reliably used for downwind sail performance prediction, it is still a useful tool for investigating the flow structure which leads to better understanding of the design space.

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  • He ao rereke : education policy and Maori under-achievement: Mechanisms of Power and Difference

    Johnston, Patricia Maringi G. (1998)

    Doctoral thesis
    The University of Auckland Library

    In acknowledging continual educational under-achievement of Maori children, this thesis investigates the relationship between education policy and Maori under-achievement. It argues that under-achievement is framed within boundaries of changing recognitions and realisations of power and difference: that conceptions of difference have influenced education policy and schooling practices for Maori. Theoretically, the thesis examines 'what counts as difference' and 'what differences count'. In recognising that unequal power relations between dominant and subordinate groups produce distinct views about difference, 'what counts as difference' encompasses the perspectives of dominant groups and 'what differences count', subordinate groups. The former view is developed to expand the basis for investigating 'Pakeha conceptions of difference', and the latter, 'Maori conceptions'. The thesis traces the interactions and relationships of 'difference' and 'power', and examines, historically, how they have contributed to and sustained Maori educational under-achievement. The contribution of these conceptions of difference to informing schooling practices is investigated through four sequential 'Classification Schemes' of Assimilation, Integration, Multiculturalism and Biculturalism. The thesis argues that Biculturalism is based on a positive view of Maori cultural differences, and examines the extent of Maori influence on four recent education policy making processes. The thesis also acknowledges a Maori focus on the importance of structural differences for addressing their needs. On the basis of those two different perspectives, the thesis develops the concepts 'Maori-friendly' and 'Maori-centred', to examine processes, and structures and the relative influence of Maori on mainstream policy forming processes. The thesis shows that Tomorrow's Schools, Education for the Twenty-First Century and the Maori Affairs Select Committee Inquiry encapsulate different degrees of both Maori-friendly and Maori-centred approaches, though arguing that ultimately, it is Pakeha conceptions of difference that inform and influence all the policy forming processes. However, the fourth policy process examined was originally a wholly Maori-centred initiative - Te Kohanga Reo. The thesis points to and traces the incorporation of Te Kohanga Reo into the mainstream education system and its consequences for Maori, and concludes that structural differences ensure continuing Pakeha control over Maori conceptions of difference and henceforth Maori educational under-achievement.

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  • Mechanical wave velocity dispersion in rods and extension of the resonant bar method to 800 KHz: a study of the velocity dispersion of longitudinal waves in rods, and a feasibility study of extending the Resonant Bar method of internal friction measurement to 1 MHz

    Booker, Rudolf Edward (1969)

    Doctoral thesis
    The University of Auckland Library

    The Resonant Bar method for measuring internal friction in solids has been investigated with the aim of extending this method to higher frequencies in the range 100 kHz to 1 MHz. This necessitated a study of the velocity dispersion of the fundamental longitudinal mode in rods of appropriate size in the region where the wavelength is of the same order of magnitude as the diameter. It is shown that the velocity dispersion of the fundamental longitudinal mode in a cylindrical rod obeys the exact solution of the Pochhammer - Chree equation calculated by Bancroft and Bradfield, over the range of diameter to wavelength ratio from zero to 2.0. The velocity dispersion of the lowest longitudinal mode of a rod of square cross-section has proved to be the same as that of a cylindrical rod of the same material, provided the equivalent diameter of the square cross-sectioned rod is taken to be 1.155 times its thickness. The theory of Nigro (1966, 1968) agreed only partially with the experimental velocity dispersion of a square rod (Booker 1969). As a result of this and a recent theory by Fraser (1969), Nigro has modified his theory, so that at present there is perfect agreement between theory and experiment. In cylindrical rods many resonant responses are excited that are not due to the fundamental mode (also called the Young's modulus mode) when the diameter to wavelength ratio becomes appreciable (usually about 0.7). These resonances are attributed to higher order longitudinal modes. Identification of the Young's modulus mode resonances becomes impossible when many of these higher order mode resonances occur. On several occasions one of the expected Young's modulus mode resonances is absent, its place being taken by two or more resonances extremely close together in frequency and of small vibration amplitude. Frequently some of the harmonics have a frequency above or below the expected value, so that they do not lie on a smooth graph of frequency versus harmonic number. It is shown that the above two phenomena occur when the value of Ω (= ωa/Ct) is close to one of the values ΩE, Ω1 to Ω2, or Ω3, where, at a value of: (1) Ω = ΩE, an end-resonance occurs; (2) Ω = Ω1, the first complex mode becomes real; (3) Ω = Ω2, the L(0,2) mode cuts the Ω axis on an Ω versus koa graph; (4) Ω = Ω3, the L(0,3) mode cuts the Ω axis. To extend the Resonant Bar method to frequencies approaching 1 MHz, it has been found essential to use rods approximately 31/2 inches long and 1/8 th of an inch in diameter. The design and construction of a bar support abstracting a negligible amount of energy from such slender rods proved almost impossible. Both a central three-pin support and a central three-wire support have proved to be unsuitable. A support consisting of two parallel horizontal tungsten wires of a quarter of a thousandth of an inch diameter has however been found to give damping values consistent to within 10%. Graphs are drawn of damping versus frequency for several aluminium and fused silica rods, showing that Q-1 varies but little with frequency and that on the whole it varies smoothly from one harmonic to the next. The Resonant Bar method is ideally suited for the determination of dynamic elastic moduli. A computer program has been developed and used to calculate Young's modulus and Poisson's ratio for any given rod from the resonance frequencies of longitudinal vibration, the dimensions and the mass.

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  • Cyclic variability in a natural gas fuelled spark ignition engine

    Chanchaona, Somchai (1990)

    Doctoral thesis
    The University of Auckland Library

    An investigation of cyclic variability in a single-cylinder spark ignition engine fuelled by natural gas was carried out. The effects of combustion chamber shape and compression ratio were examined intensively. Four different combustion chambers were tested and compression ratio was varied in the range of 8.5:1 to 15:1. For each test condition, the in-cylinder pressure data were recorded at each degree of crank angle rotation for a total of two hundred consecutive engine cycles. These pressure-time histories were used for the detailed study of combustion characteristics. The generalized plot of maximum pressure and location at which maximum pressure occurs was demonstrated as an effective means of diagnosing the cyclic variability. It was shown that compression ratio had negligible effect on cyclic variability, but combustion chamber shape had a strong influence. The indicated mean effective pressure proved to be a good index for measuring cyclic variability for a wide range of operating conditions. However, for specific cases in which the variation of indicated mean effective pressure shows poor sensitivity, maximum pressure and maximum rate of pressure rise are useful measures. For high compression ratio engines, a compact combustion chamber arranged around the spark plug has been shown to be superior for reducing cyclic variability. In addition, a study of a model for the small-scale structure of turbulence using the data from these experiments showed good agreement with those from the literature. Alternative assumptions for estimating turbulence length scale were tested and a preferred method is recommended. The study showed that the fast burning combustion chamber is the solution to reduce cyclic variation. However, cyclic variations of maximum pressure and its location in the fast burning condition still exist and continued research to reduce these cyclic variations should concentrate on the variation of characteristics of flame kernel creation and growth from cycle to cycle.

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  • Mountain beech forest on Mount Ruapehu: dynamics, disturbance, and dieback

    Steel, Marion Gaynor (1989)

    Doctoral thesis
    The University of Auckland Library

    The role of, and response to, disturbance, in the dynamics of the mountain beech forest at western Mt Ruapehu, was examined, using palynology, dendrochronology, and vegetation survey. The pollen record indicates that, two thousand years ago, the west Ruapehu forest was dominated by Nothofagus solandri. About 1800 years B.P., the eruption of Lake Taupo devastated the forest. Though Halocarpus spp. and Phyllocladus asplenifolius were important early colonizers, Nothofagus solandri re-established itself close to its present limits after the eruption. Fire, from about 650 years ago onwards, did not affect the beech forest, but did affect the coniferous vegetation on the ring plain near the mountain. The age structure of the forest shows that there was a large disturbance event shortly before 1740. A dieback occurring about 1969 appears to have been the largest episode of mortality since 1740, larger than the dieback episode described by Cockayne at the beginning of this century. Dieback occurred as a short peak-period of Nothofagus solandri death about 1969. It was the large trees of the mature cohort which tended to be killed by dieback rather than the smaller individuals. Tree-ring analysis, showed that narrow tree-rings occurred in beech in the 1960's. Extreme rainfall years in the early 1960's may have put the beech trees under stress, making them susceptible to dieback. The drought in 1969 may have precipitated extensive mortality. The characteristics of N. solandri rings from Ruapehu are similar to ring characteristics of that species from South Island studies. The 1982 cyclone had a noticeable impact on the forest, affecting some areas severely. However, the impact was relatively minor compared to the influence of dieback. The mean density of trees >= 10cm dbh was 520 stems/ha., of which 220 stems/ha. were Nothofagus solandri. The mean basal area was 22m2 /ha., of which 11m2 /ha. was N. solandri. The basal area is very low compared to that in other N.Z. forests. N. solandri, Griselinia littoralis, Phyllocladus asplenifolius, Podocarpus hallii, and Libocedrus bidwillii, made up 35, 22, 16, 9, and 8 percent, respectively, of the total density. Basal area, density, and species composition varied as much within sites, as between them. The shrub layer formed a large part of the vegetation at west Ruapehu. Coprosma species were particularly abundant. There is sufficient regeneration to indicate that a new cohort of N. solandri is becoming established in most areas. Some areas will probably remain in shrubland for many decades. The result of dieback and windthrow has been to virtually eliminate the canopy of large old beech trees, and to increase the heterogeneity of stand structure. N. solandri seedling densities are not as high as those found in many South Island beech forests. Nothofagus solandri is growing faster than are most of the co-existing tree species, and it appears likely that it will continue as the dominant tree species. Implications for forest management are discussed.

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  • Tracer testing of geothermal reservoirs

    Bullivant, David Peter (1988)

    Doctoral thesis
    The University of Auckland Library

    A new model is presented to explain the results of tracer tests of reservoirs. The flow field model is two-dimensional and can include multiple wells, background flow and a high permeability fracture of finite length or a barrier of finite length - likely features of a reservoir in fractured rock. The flow field is represented by a complex potential. This enables the accurate calculation of the time for tracer to travel along the streamline linking the release position and the observation well. The shape of the concentration curve measured at the observation well is governed by dispersion. Two types of dispersion are considered – small scale dispersion and large scale dispersion. Small scale dispersion is due to interaction with the rock matrix and to small scale variations in velocity (not included in the flow field model), in the neighbourhood of a streamline. Large scale dispersion is due to the spread of tracer over streamlines which have different travel times to the observation well and may go to different observation wells. In the literature, small scale dispersion models are used to match the concentration curves for individual wells. Here it is shown that models with differing small scale mechanisms give equally good matches to Wairakei data and that response curves for small scale dispersion and large scale dispersion are similar. This means that the shape of a concentration response curve gives little information about reservoir structure. The important results from a tracer test are whether tracer is detected at each observation well and the travel times to the wells that respond, in conjunction with the locations of the release and production wells. This new approach to analysing tracer tests is used together with the flow field model to deduce the permeability structure and flow field of a simple hypothetical reservoir and of the Wairakei (New Zealand) geothermal reservoir.

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  • Tastant interactions with model membranes

    Shaw, Patricia (1993)

    Doctoral thesis
    The University of Auckland Library

    A wide range of compounds elicit the sweet taste response but currently it is not known what causes this response. In Chapter 3 a number of sweeteners, and representatives of all the taste groups are investigated using NMR spectroscopy. The T1 relaxation times of the tastants were determined in aqueous solution and in solution with liposomes, a model membrane system. The observed changes in T1, values are analysed to determine which regions of the tastants are involved in the interaction with the membrane. In Chapters 4 and 5 an investigation is reported of the interaction of tastants with a liquid membrane system, which is reportedly able to distinguish between classes of chemicals. The interest lies in developing a simple experiment that will enable taste qualities to be predicted, something that is currently not possible. In Chapters 6 and 7 the NMR assignments of some sweeteners is discussed. NMR assignments are a necessary precursor before their sweetening properties can be studied by NMR.

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  • The solution of the order conditions for general linear methods

    Heard, Allison (1978)

    Doctoral thesis
    The University of Auckland Library

    The introductory chapter in this thesis examines briefly the nature of initial value problems and surveys the main types of methods used for their numerical solution. The general linear formulation of methods, first proposed by J. C. Butcher, is introduced, together with the definition of order for this class of methods. Finally in this chapter, the problem of stiffness and its effect on numerical procedures is considered. Following a review of Butcher's algebraic approach to the theory of Runge-Kutta and general linear methods in Chapter 2, the theory is applied in Chapter 3 to the search for general linear methods of various orders. As in the case of Runge-Kutta methods, the use of so-called simplifying assumptions plays a significant role in the practical determination of general linear methods. From amongst the range of possible numbers of simplifying assumptions, two cases are chosen and investigated in detail. The important question of stability is considered in the final section of Chapter 3. When a general linear method is used to approximate the solution of an initial value problem, special procedures are required to start and finish the integration. Whilst a major part of Chapter 4 is devoted to the determination of these procedures, the problems of the estimation of local truncation error and the implementation of general linear methods are also discussed. Finally, the Appendices contain Algol 60 procedures for the most important of the algorithms developed in the main body of the thesis.

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  • Towards a theory of the configuration and management of export-dependent land-based value systems: The case of New Zealand

    Lockhart, James C. (1997)

    Doctoral thesis
    The University of Auckland Library

    Subscription resource available via Digital Dissertations Land-based industries provide the majority of New Zealand's export earnings. The scale of production in the larger industries accounting for this trade creates significant dependency on export markets. The performance of these industries in the international location, therefore, has a marked influence on the country's prosperity. The process of taking land-based products from pasture to plate encompasses a value system. A value system (depicted as the Z-form Model, overleaf) includes all sequentially aligned organisations through which product flows from the producer to the international consumer. Value systems also include the linkages between adjoining and non-adjoining organisations. The objective of the study was to develop a theory of the configuration and management of export-dependent land-based value systems, supported by case study material drawn from select New Zealand industries. The Z-form Model constituted a framework from which both relevant contributions and shortcomings in the literature were identified. A conjoint approach to theory building, encompassing both theoretical and empirical contributions, was developed. Empirical evidence was then gathered through multiple case studies of the meat and pipfruit industries to augment theory building. Particular attention was paid to empirical processes relating to the generation of wealth and its subsequent distribution. Phenomena observed through case research were reduced into concepts, and the relationships between concepts identified. Concepts and relationships were then presented as an emergent theory in the form of a causal network. Some of the perspectives and behaviours of value systems were supported by the literature, however, many considerations were found to be unique. A theory of the configuration and management of New Zealand's export-dependent value systems is presented. The theory encompasses empirically based value system strategies that serve to enhance wealth generation and wealth distribution. Normative value systems, based on the Z-form Model, that return wealth to organisations in the home-base location are provided. Further opportunities for wealth creation and repatriation are identified.

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