14,528 results for University of Canterbury Library

  • Hydrodynamics and chemistry of silica scale formation in hydrogeothermal systems.

    Kokhanenko, Pavlo (2015)

    Doctoral thesis
    University of Canterbury Library

    The extraction of geothermal heat can cause precipitation of the minerals dissolved in geothermal fluid. Their deposition on the walls of wells and above-ground plant and in pores near reinjection wells, also known as mineral scaling, is one of the main obstacles to increasing the effectiveness of utilization of the limited geothermal resources. If not controlled properly it can result in accumulation of a significant amount of scale which obstructs pipes and reinjection wells and reduces the efficacy of heat exchangers. The most abundant mineral in geothermal fluid is silica and thus its precipitation can cause the highest scaling rate. While this dissertation is devoted to the study of silica scaling the results obtained may be applicable to other minerals with similar deposition mechanism. Oversaturated silica is known to precipitate from aqueous solution either by the direct chemisorption of single silicic acid molecules (monomers) or by forming colloidal particles suspended in the solution. These particles can subsequently be transported to, and attach onto, a wall. This process of colloidal silica deposition was previously recognised to cause much faster scaling than the direct deposition of silica monomers under typical geothermal plant conditions. While the chemical kinetics of silica polymerization and colloid formation are relatively well understood, transport of these colloids and their stability, which control their aggregation and attachment rates, on the other hand are not. Previous studies of the silica scaling process have identified prominent effects of geothermal brine hydrodynamics on the scaling rate. It was found to increase with the flow rate and particle size, thus suggesting the dominance of the advective (inertial) deposition of colloidal silica. However, this conclusion contradicted the present theory of particle transport in turbulent flows which argues the dominance of the diffusive transport for the relevant range of particle sizes (<1 μm). The development and continuing improvement of the anti-scaling measures required deeper understanding of the complex combination of the phenomena involved in the process of silica scaling. This was pursued in the present study using theoretical and experimental methods. First, the rate of colloidal silica transport from a turbulent flow onto the internal surface of a circular pipe, a cylinder and a flat plate were calculated using available analytical and numerical methods. The obtained theoretical transport rate was found to be about four orders of magnitude higher than the corresponding experimental scaling rate. The latter was determined in the previous studies to be 4.2·10-8 kg/s/m2 for silica colloids of 125 nm in diameter which corresponded to the dimensionless deposition velocity (the dimensionless deposition velocity is the scaling rate normalised by the particle mass concentration and friction velocity) of 1.2·10-6 for the dimensionless particle relaxation time of 2·10-4. Next, based on the standard DLVO theory of particle interactions and in the framework of the Smoluchowski approach the probability of colloidal silica particle attachment to a wall was found to be 10-6. Therefore, the theoretical scaling rate, calculated as a product of this probability and the above-mentioned transport rate was two orders of magnitude lower than the experimental scaling rate. This suggested that the implemented theoretical approach either underestimated particle transport rate or overestimated particle stability. Both possibilities are explored in this dissertation. In addition, the silica scaling rate was measured for a range of conditions: particle size from 20 to 60 nm, particle concentration 1600-10000 ppm, friction velocity from 0.09 to 0.18 m/s (Re = 9-50·103) and ionic strength from 30 to 80 mM, pH 8.1-9.5 and temperature from 25 to 44 °C. For this, laboratory experiments were designed and progressively modified in order to improve the repeatability of the results and to study the scaling process. In these experiments colloidal silica deposition onto the walls of mild steel pipe sections was studied with a recirculating flow rig with variable (but controllable) particle size, concentration, flow rate, pH and ionic strength of the solution. In addition, a parallel plate flow test section was designed and built which will provide better capabilities for the control over the hydrodynamic and test surface conditions in future experiments. The control over the chemical conditions was achieved by the use of the synthetic colloidal solutions. Two methods of their production – hydrolysis of either sodium metasilicate or active silicic acid – were employed. The influence of the synthesis conditions, ion content and pH on the long term behaviour of these colloidal solutions was investigated. The particle size data, obtained using dynamic light scattering (DLS) and verified by electron microscopy, was analysed and compared against the predictions of the current models of nanoparticle growth and stability. The kinetic aggregation was identified to be the dominant particle growth mechanism. Experimental data collected during the long-term observations of the particle growth allowed relationships between the aggregative stability and such parameters as the particle size, ion concentration and pH of the solution to be elucidated. In particular, the aggregative stability of 10-20 nm particles was found to be 108-1010 which is 7-9 orders of magnitude higher than the corresponding DLVO stability. It was also found to decrease with the increase of the particle size. This agreed with the theory of the colloid stabilization by steric interactions. Moreover, the model of the “gel” layer was used to explain the observed “anomalies” of the colloidal silica behaviour. The deposition experiments conducted with these synthetic colloidal solutions showed that the scaling rate increased with the particle size, flow rate and ionic strength (IS) of the solution. Thus, it was measured to be 9.7·10-9 kg/s/m2 for the 45 nm particles in a solution with IS = 0.05 M, which corresponded to the dimensionless deposition velocity of 6.6·10-8 for a dimensionless particle relaxation time of 2.2·10-6. The scaling rate was calculated for these conditions by multiplying the corresponding transport rate and the actual attachment probability determined as an inverse of the experimental stability. It was found to agree with the experimental value within an order of magnitude. In addition, the observed increase of the scaling rate with the increase of particle size was explained by the compensation of the decreased rate of the particle transport by faster decrease of actual particle stability (increase in attachment probability). Therefore the contradiction between the theory and the experiment was resolved for the particles of 20 to 60 nm in diameter. Moreover, the observations of the dimensions and distribution of the scale elements formed in some of the present experiments strongly suggested the significance of the advective (inertial) mechanism of particle deposition. This and comparative analysis of other experimental and theoretical data suggested that the present theory may underestimate the convective transport of the particles onto a rough wall. Therefore, the hypothesis of the parallel-to-wall advective deposition of the nanoparticles onto the roughness/scale elements (not accounted in the current theory) was proposed. The corresponding mass transfer problem was solved analytically using experimentally found dimensions of the scale elements. The additional transport was found to decrease the above-stated discrepancy between the theoretical and experimental scaling rate for large (125 nm) particles by one order of magnitude. The remaining difference of one order of magnitude was speculated to be due to the underestimation of these particles attachment probability derived with the standard DLVO theory. The actual aggregative stability of the silica colloids larger than 60 nm in diameter and for a wider range of IS values is of interest for future experimental studies. An improved understanding of the interrelation between the chemical and hydrodynamic phenomena in the process of silica scaling and its dominant mechanisms was achieved in this dissertation. This allowed optimization of the present anti-scaling practices aimed to minimize the negative effects of mineral scaling on the operation of geothermal power stations. Besides the practical recommendations, which may ultimately help to increase the efficiency of geothermal power stations, the results of the present study may be of value in the fields of mass transfer and colloid science.

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  • Development and optimization of an in vitro process for the production of Oryctes nudivirus in insect cell cultures

    Pushparajan, Charlotte (2015)

    Doctoral thesis
    University of Canterbury Library

    The coconut rhinoceros beetle, an economically important pest of coconut and oil palms, is effectively managed by application of its natural pathogen, the Oryctes nudivirus (OrNV), which act as a bioinsecticide. While this approach offers an environment-friendly alternative to chemical pesticides, the current method of production in infected larvae suffers from inconsistencies in virus productivity and purity. While the anchorage-dependent DSIR-HA-1179 insect cell line has been identified as a susceptible and permissive host for OrNV and therefore would be suitable for the in vitro mass production of the virus, no attempts have been made toward the mass production of the virus, because of the technological challenges that working with DSIR-HA-1179 cells represent. Thus, the main objective of this research was to develop processes for the in vitro production of OrNV in the DSIR-HA-1179 cell line. Knowledge of the growth kinetics and metabolic properties of the host cell line in a chosen culture medium, as well as the selection of an appropriate infection strategy, form the basis for the rational development of bioreactor-based virus production processes. However, characterization of these properties in the DSIR-HA-1179 cell line has been virtually precluded, due to its strongly adherent growth characteristics and the lack of a reliable method to accurately dissociate and count cells grown in monolayers. Using TrypLE™ Express enzyme, a technique allowing the precise counting of cells was developed. The cell line was adapted to grow in four serum-supplemented culture media: TC-100, IPL-41, Sf-900 II and Sf-900 III, which were then individually screened for cell growth and virus production in 25 cm2 attached T-flask cultures. TC-100 supplemented with 10% fetal bovine serum was chosen as a suitable culture medium, based on its capacity for achieving a high cell yield and OrNV production. The cell line metabolism was characterized with respect to nutrient consumption and metabolites production in this culture medium. Glucose, along with glutamine were found to be the nutrients that were consumed faster and to a greater extent, while other amino acids were not consumed to a significant degree. The production of metabolites was characterized by non-production of lactate and ammonia, and production of alanine, as a non-toxic alternative to ammonia. The influence of cell density (CD) at time of infection (TOI) and multiplicity of infection (MOI) on OrNV production was evaluated in T-flask cultures that were infected at different CDs at the TOI and a range of MOIs. The CD at TOI was found to significantly influence OrNV yields, while MOI influenced the dynamics of infection. The cell density effect was found to exist for the DSIR-HA-1179/OrNV system with the progressive decline in cell-specific yield beginning at low cell densities. It was found that in order to maximize OrNV volumetric yield, a combination of MOI and CD at TOI should be selected that allows to keep the maximum cell density reached by the infected culture within a range between 5.0 and 7.0 x 105 viable cells/ml. The roller bottle system was evaluated for its potential to scale-up DSIR-HA-1179 cell growth and OrNV production, and culture parameters were optimized for the improvement of cell and virus yields. An inoculum density of 3.3 x 105 cells/ml and culture volume of 60 ml resulted in the highest cell yield of 1.5 x 106 cells/ml, in 490 cm2 roller bottles. It was found that an optimal infection strategy for roller bottle cultures, which represented the most efficient use of viral inoculum, involved infecting cells at a density of 5.0 x 105 cells/ml and at a MOI of 1. The resulting OrNV volumetric yield of 2.5 x108 TCID50/ml, improved significantly the viral yields obtained in attached T-flask cultures infected under similar conditions (6.8 x 107 TCID50/ml). The microcarrier system was also evaluated for culturing DSIR-HA-1179 cells and producing OrNV in spinner flask bioreactors. Three types of microcarriers (Cytodex-1, Cytodex-3 and Cultispher-G microcarriers) were screened for their ability to support DSIR-HA-1179 growth. Cells attached to Cytodex-1 and 3, but failed to attach to Cultispher-G microcarriers. The final cell density reached in microcarrier culture was dependent on bead type and concentration, and the cell to bead ratio. At an optimal bead concentration of 1 mg/ml and cell to bead ratio of 30, cells grew to a maximum density of 1.7 x 106 cells/ml on Cytodex-1, but only to 1.3 x 106 cells/ml on Cytodex-3 microcarriers. Since it supported higher cell yields, Cytodex-1 was chosen to study the kinetics of OrNV production in this system. Microcarrier cultures infected at a cell density of 5.0 x 105 cells/ml and a MOI of 1, produced OrNV at 1.4 x 108 TCID50/ml, which was higher than the yield obtained in T-flask cultures infected under similar conditions. A framework of knowledge on the physiology, metabolism and growth kinetics of the DSIR-HA-1179 insect cell line has been developed in this thesis. In addition, the feasibility of using roller bottles and microcarrier systems for the in vitro production of the virus has been ascertained. It is envisaged that these findings will contribute to the future development of a large-scale industrial process for the production of the OrNV biopesticide.

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  • Irradiation as an alternative phytosanitary treatment for Arhopalus ferus and Hylurgus ligniperda

    van Haandel, Andre (2014)

    Bachelors thesis
    University of Canterbury Library

    Wood products all require treatment to mitigate phytosanitary risk prior to exportation. The most common phytosanitary treatment applied to Pinus radiata logs is Methyl Bromide (MeBr). The Environmental Protection Agency (EPA) in 2010 stated that MeBr must not be release into the atmosphere past 2020. This poses a problem for New Zealand log exports. Radiation has been identified as a possible alternative phytosanitary treatment for export wood products. This study aimed to quantify the effective dose of radiation necessary to sterilise two forest pest species; Arhopalus ferus and Hylurgus ligniperda. These species are representative of two different types of forestry pests; bark beetles (H. ligniperda) and wood borers (A. ferus). All applicable life stages for both species were tested. Arhopalus ferus adults were the most susceptible life stage identified with an LD99 of 30.2Gy ± 13.5 Gy (95% confidence interval). Arhopalus ferus eggs were less susceptible with a LD99 of 750Gy ± 776Gy observed; however there is low confidence in this result due to a methodological issue in one treatment replicate. Hylurgus ligniperda eggs were observed to be less susceptible than A. ferus eggs with a LD99 of 289Gy ± 92Gy. Results for the other life stages were inconclusive due to poor control survival, however the information gained was used to develop improved methods for further experimentation, which is on-going and showing positive results so far. The results of this experiment have indicated that radiation can be an effective method of sterilising forestry pests. To date radiation has not been used as phytosanitary risk mitigation for wood exports; however it is widely used for risk mitigation in agricultural products. Currently there remains a large amount of unknown information regarding, the effectiveness for irradiation of logs, the effective dose require for sterilisation of the most tolerant forestry pest and public acceptability of irradiation as a phytosanitary treatment. These knowledge gaps and an economic assessment must be completed before irradiation can be used as a phytosanitary risk mitigation technique for forestry products.

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  • Gold-based Nanomaterials: Spectroscopy, Microscopy and Applications in Catalysis and Sensing

    Adnan, Rohul (2015)

    Doctoral thesis
    University of Canterbury Library

    The birth of nanotechnology era has revolutionized materials science, catalysis and field of optoelectronics. Novel and unique phenomena emerge when material dimensions are reduced to ultra-small size regime and enter nanometre (2-100 nm) realm. Such novel materials are expected to replace bulk materials, offering lower cost of manufacturing and enabling progress in many areas such as solar cell, drug delivery, quantum communication and computing, catalysis and sensing applications. With the progress in nanomaterial synthesis and fabrication, the need for the state-of-art characterization techniques became obvious; such techniques help to establish a complete understanding of the nature and interactions of nanosized materials. In this thesis, the first part focuses on the synthesis of gold and ruthenium clusters, namely Au8, Au9, Au101, Ru3, Ru4 and AuRu3, using the well-established synthetic protocols in the literature. Apart from the standard lab-based characterization techniques such as nuclear magnetic resonance (NMR), UV-visible spectroscopy (UV-vis) and Fourier Transform Infra-red (FTIR), a less explored but useful technique far infra-red (far IR) spectroscopy, available at the Australian Synchrotron (AS), was employed to investigate the vibrational modes in these clusters. Peaks in the experimental far IR spectra were assigned unambiguously to specific vibrations by comparing with the ones generated via DFT calculations with the help of collaborators, group of Professor Gregory Metha, University of Adelaide. For the Au9 cluster, three significant gold core vibrations are observed at 157, 177 and 197 cm-1 in the experimental spectrum. In the case of the Ru3 cluster, only a single ruthenium core vibration is identified within the spectrum, at 150 cm-1 with the calculated force constant, k = 0.33 mdyne/Å. The Ru4 cluster exhibits two metal core vibrations at 153 and 170 cm-1 with force constants of 0.35 and 0.53 mdyne/Å, respectively. Substitution with a gold atom yielding a mixed metal AuRu3 cluster shifts the core transitions toward higher wavenumbers at 177 and 299 cm-1 with an increase in force constants to 0.37 and 1.65 mdyne/Å, respectively. This is attributed to the change in chemical composition and geometry of the metal cluster core. A combination of the DFT calculations and high quality synchrotron-based experimental measurements allowed the full assignment of the key transitions in these clusters. Next, these clusters were fabricated into heterogeneous catalysts by depositing on different metal oxide nanopowders. Synchrotron X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS) studies were performed at the Australian Synchrotron and the Photon Factory synchrotron in Japan to investigate the electronic structure of Au8, Au9 and Au101 on TiO2 catalysts. The XPS analysis reveals that “as-deposited” Au8 and Au9 retain some un-aggregated clusters while Au101 show bulk-like gold. These findings are in line with TEM observations, where the aggregates (large particles, > 2 nm) of Au8, Au9 and Au101 are hardly seen under HRTEM. UV-visible diffuse reflectance spectroscopy (UV-vis DRS) studies show the absence of localised surface plasmon resonance (LSPR) peaks in these “as-deposited” clusters, suggesting they are below 2 nm in size. Importantly, the XAS spectrum of “as-deposited” Au9 clusters estimates that 60% of pure, un-aggregated Au9 clusters and 40% of bulk gold in the sample. Upon calcination under O2 and combined O2 and H2 (O2-H2), Au8, Au9 and Au101 clusters form larger nanoparticles (> 2 nm) with the appearance of LSPE peak in UV-vis DR spectra. In addition, majority of the phosphine ligands (that stabilise the gold core) dislodge and form phosphine oxide-like species by interacting with oxygen on the TiO2 surface. The third part focused on testing the catalytic performance of the supported Au8, Au9, Au101, Ru3, Ru4 and AuRu3 clusters on different TiO2, SiO2, ZnO and ZrO2 in benzyl alcohol oxidation. Au101-based catalysts display the highest catalytic activity with a turn-over frequency (TOF) up to 0.69 s-1. The high catalytic activity is attributed to the formation of large Au nanoparticles (> 2 nm) that coincides with the partial removal of capping ligands. Au8 and Au9 clusters which contain NO3- counter anions are found to be inactive in benzyl alcohol oxidation. Further work shows that the presence of NO3- species diminishes the catalytic activity. Monometallic ruthenium clusters, Ru3 and Ru4, are found to be inactive yet the bimetallic AuRu3 clusters are active in benzyl alcohol oxidation, suggesting the synergistic effect between ruthenium and gold metal. Investigation of catalytic testing parameters reveals that tuning selectivity of the product is possible through manipulating the reaction temperature. Finally, a joint experiment with Prof. Wojtek Wlodarski’s group at RMIT, Melbourne was undertaken to test the sensing ability of Au9 clusters for hydrogen detection. Au9 clusters were deposited onto radio-frequency (RF) sputtered WO3 films at two different concentrations; 0.01(S1) and 0.1(S2) mg/mL. It was found that the optimal temperatures for sensor S1 and S2 were 300 °C and 350 °C, respectively. The sensor with lower Au9 concentration (S1) displays a faster response and recovery time, and a higher sensitivity toward H2. HRTEM studies reveal that the sensor S1 contain a significant population of sub-5 nm Au nanoparticles which might be responsible for a faster rate of H2 adsorption and dissociation. The key finding in this study suggest that the addition of catalytic layer such as ultra-small Au9 clusters results in improved sensitivity and dynamic performance (response and recovery time) of H2 sensors. In summary, this thesis demonstrated that cluster-based nanomaterials have wide range of applications spanning from catalysis to sensing. Further improvements in material synthesis and use of multiple complimentary characterization techniques allowed better understanding of the nature of the key active species (metal nanoparticles) assisting design of catalysts and sensors with enhanced performance.

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  • Managing Non-Traditional Security Concerns in the Context of Competing Maritime Claims: A Path to Peace or a Road to Nowhere

    Scott, K. N. (2014)


    University of Canterbury Library

    The South China Sea (SCS), which extends over 3.5 million kilometres with an average depth of 2000 metres1 has become synonymous with intractable territorial and maritime delimitation disputes with the disagreement over the Spratly Archipelago (involving six nations - China, Taiwan, Vietnam, Malaysia, Brunei, Philippines) and the Paracel Archipelago (3 nations – Vietnam, China and Taiwan) being the most high profile of the disputes. What I would like to do in this paper, as part of this project, is to explore the extent to which a focus on non-traditional security concerns actually represents a viable pathway either to the resolution of the territorial and maritime delimitation disputes between the competing claimants or to the development of a long term interim solution whereby a framework is developed allowing states to manage the region without resolving those disputes.

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  • Small business tax compliance burden : what can be done to level the playing field.

    Ma, David (2015)

    Masters thesis
    University of Canterbury Library

    One of the major issues associated with taxation are the costs incurred by taxpayers when they comply with their tax obligations, this is particularly important for smaller business taxpayers. Compliance costs are found to be regressive, falling with disproportionate severity on smaller businesses. This trend can be found across the globe and more importantly, in New Zealand. Prior research has shown that the severity of the regressiveness has increased over time. The current, “one-size-fits-all”, approach used in the New Zealand tax system, and others alike, have created undue complexity for small businesses. This study reviews small business tax regimes and concessions currently implemented (or proposed) in different countries to relieve the compliance burden for smaller businesses. Australia, South Africa, the United Kingdom and the United States have either implemented a separate tax regime, or offers tax concessions to smaller business taxpayers. New Zealand on the other hand, presents minor ad hoc tax concessions for small business taxpayers, but since 2009, there have been proposals to change this system. This study evaluates and compares all the implemented (or proposed) regimes and concessions of the selected countries. Following from the case studies, interviews are conducted with tax professionals that have worked closely with smaller businesses, in order to shed light on the possibility of implementing a similar regime in New Zealand. The findings show that a small business tax regime has many avenues to consider, however, there is general consensus that suggests small business taxation should be kept as simple as possible. This thesis puts forward a baseline for further discussion and development of a small business regime to reduce compliance costs for smaller businesses.

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  • Investigation and Prediction of the Sound Transmission Loss of Plywood Constructions

    Wareing, Robin Richard (2015)

    Doctoral thesis
    University of Canterbury Library

    The sound transmission loss of a range of plywood panels was measured to investigate the influence of the orthotropic stiffness of the plywood panels. The plywood panels were tested as single and also double leaf partitions, with a range of stud configurations. A new method was developed for predicting the sound transmission loss of single leaf partitions with both orthotropic and frequency dependent stiffness values. The sound transmission loss was evaluated for two significantly different sample sizes. The observed influence of the sample size on the measured sound transmission loss was profound. The construction of the partition was shown to significantly affect the influence of the sample size on the sound transmission loss. A qualitative analysis based on existing published research of the contributing factors is presented, and methods for adjusting the results for the small sample size for comparison with the large results were developed. The influence of a range of acoustic treatments of lightweight plywood partitions was investigated. The treatments involved internal viscoelastic materials and decoupled mass loaded barriers in various arrangements. The attachment between the treatment and the plywood panel was found to influence the sound transmission loss significantly. A prediction method based on published models was modified to allow the influence of the treatments to be included. Reasonable agreement was achieved between the predicted and measured results for a wide range of samples. A prediction method was developed that accounts for the influence of orthotropic, frequency dependent material parameters. This method utilised an adaptive, numerical integration method to solve an analytical formulation for the sound transmission loss. The influence of the finite sample size was accounted for using an expression for the finite panel radiation impedance. The finite panel radiation impedance was predicted analytically and an approximation was also presented. The presence of a significant source room niche was accounted for by applying an appropriate limit to the integration range of the angle of incidence. The prediction methods developed are compared with the measured transmission loss results from both the small and large test facilities. Good agreement was seen for some of the predicted results. Generally the agreement within the coincidence region was worse than for the rest of the transmission loss curve. The inclusion of orthotropic and frequency dependent stiffness values significantly improved the agreement within the coincidence region.

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  • A Capabilities Solution to Enhancement Inequality

    Swindells, Fox (2014)

    Masters thesis
    University of Canterbury Library

    Human enhancements will dramatically alter individuals' capabilities and lead to serious harm if unregulated. However, it is unclear how states should act to mitigate this harm. I argue that the capabilities approach provides a useful metric to determine what action states should take regarding each enhancement technology. According to the capabilities approach, states are responsible for ensuring their citizens are able to function in certain ways that are essential to human life. I consider the impact of a range of enhancements on individuals' capabilities in order to determine what actions states should take regarding each technology. I find that in order to be just and prevent harmful inequality, states will need to ensure many enhancements are available to their citizens. I also explore a range of other regulations aimed at harm prevention. Considering the impact of enhancement technologies on human capabilities, and the appropriate regulatory options for states, under the guide of the capabilities approach allows me to demonstrate that the capabilities approach can provide valuable, realistic, advice to guide public policy in response to enhancement technologies.

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  • Refinement and Normalisation of the University of Canterbury Auditory-Visual Matrix Sentence Test

    McClelland, Amber (2015)

    Masters thesis
    University of Canterbury Library

    Developed by O'Beirne and Trounson (Trounson, 2012), the UC Auditory-Visual Matrix Sentence Test (UCAMST) is an auditory-visual speech test in NZ English where sentences are assembled from 50 words arranged into 5 columns (name, verb, quantity, adjective, object). Generation of sentence materials involved cutting and re-assembling 100 naturally spoken ‟original” sentences to create a large repertoire of 100,000 unique ‟synthesised” sentences. The process of synthesising sentences from video fragments resulted in occasional artifactual image jerks (‟judders”)‒quantified by an unusually large change in the ‟pixel difference value” of consecutive frames‒at the edited transitions between video fragments. To preserve the naturalness of materials, Study 1 aimed to select transitions with the least ‟noticeable” judders. Normal-hearing participants (n = 18) assigned a 10-point noticeability rating score to 100 sentences comprising unedited ‟no judder” sentences (n = 28), and ‟synthesised” sentences (n = 72) that varied in the severity (i.e. pixel difference value), number, and position of judders. The judders were found to be significantly noticeable compared to no judder controls, and based on mean rating score, 2,494 sentences with ‟minimal noticeable judder” were included in the auditory-visual UCAMST. Follow-on work should establish equivalent lists using these sentences. The average pixel difference value was found to be a significant predictor of rating score, therefore may be used as a guide in future development of auditory-visual speech tests assembled from video fragments. The aim of Study 2 was to normalise the auditory-alone UCAMST to make each audio fragment equally intelligible in noise. In Part I, individuals with normal hearing (n = 17) assessed 400 sentences containing each file fragment presented at four different SNRs (-18.5, -15, -11.5, and -8 dB) in both constant speech-shaped noise (n = 9) and six-talker babble (n = 8). An intelligibility function was fitted to word-specific data, and the midpoint (Lmid, intelligibility at 50%) of each function was adjusted to equal the mean pre-normalisation midpoint across fragments. In Part II, 30 lists of 20 sentences were generated with relatively homogeneous frequency of matrix word use. The predicted parameters in constant noise (Lmid = 14.0 dB SNR; slope = 13.9%/dB ± 0.0%/dB) are comparable with published equivalents. The babble noise condition was, conversely, less sensitive (Lmid = 14.9 dB SNR; slope = 10.3%/dB ± 0.1%/dB), possibly due to a smaller sample size (n = 8). Overall, this research constituted an important first step in establishing the UCAMST as a reliable measure of speech recognition; follow-on work will validate the normalisation procedure carried out in this project.

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  • “You Want To Capture Something that Will Make People Change”: Rhetorical Persuasion in The Cove, Whale Wars, and Sharkwater.

    Stewart, Jessica (2014)

    Masters thesis
    University of Canterbury Library

    Dolphins, whales, and sharks are some of the world’s most iconic animals. Yet, many people will only ever see these animals via the media. The media, then, hold significant power in creating, modifying, or reaffirming the imaginaries around various species which, in turn, influences how much concern is given to matters related to their welfare and conservation. Given the environmental and ecological concerns presently facing the ocean, protecting, conserving, and preserving the marine ecosystem is vital, and time is of the essence. Through the work of activists, three specific marine wildlife issues have received a lot of publicity across various forms of mainstream media: the killing of dolphins in Taiji, Japan for their meat; Antarctic whaling; and the practice of shark-finning. Three activist films, namely The Cove (2009), Whale Wars (2008-), and Sharkwater (2006), are centred on these issues, and filmmakers attempt to compel viewers to support the activists’ protectionist cause. In order for this goal to have a chance of coming to fruition, rhetorical arguments must be carefully crafted. Yet, the study of rhetoric in animal-focused activist films is still an understudied research area. This thesis contributes to this area of research by using the aforementioned films as case studies by applying Aristotle’s rhetorical proofs of ethos, pathos, and logos to analyse the rhetorical arguments. Ethos is demonstrable when the activists construct themselves as credible, moral heroes and the animals as possessors of positive traits worth protecting, and the hunters as immoral villains. The graphic imagery of animal death appeals to pathos to stir strong bodily and emotional responses such as sadness, and disgust in order to mobilize audience support for cause. Lastly, these films appeal to logos through the use of culturally authoritative discourses such as those of biology, western conventional medicine, and the legal system. This thesis essentially argues that these texts work rhetorically and discursively to persuade audiences to feel a connection with and sympathy towards the animals; to be supportive of the activists; and to prompt antipathy towards the hunters and industry spokespeople.

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  • The temperature dependence of the far-infrared-radio correlation in the Herschel-ATLAS

    Smith, D.J.B.; Jarvis, M.J.; Hardcastle, M.J.; Vaccari, M.; Bourne, N.; Dunne, L.; Ibar, E.; Maddox, N.; Prescott, M.; Vlahakis, C.; Eales, S.; Maddox, S.J.; Smith, M.W.L.; Valiante, E.; de Zotti, G. (2014)

    Journal Articles
    University of Canterbury Library

    We use 10,387 galaxies from the Herschel Astrophysical TeraHertz Large Area Survey (HATLAS) to probe the far-infrared radio correlation (FIRC) of star forming galaxies as a function of redshift, wavelength, and effective dust temperature. All of the sources in our 250 μmselected sample have spectroscopic redshifts, as well as 1.4GHz flux density estimates measured from the Faint Images of the Radio Sky at Twenty centimetres (FIRST) survey. This enables us to study not only individual sources, but also the average properties of the 250 μm selected population using median stacking techniques. We find that individual sources detected at 5 in both the H-ATLAS and FIRST data have logarithmic flux ratios (i.e. FIRC q parameters) consistent with previous studies of the FIRC. In contrast, the stacked values show larger q , suggesting excess far-IR flux density/luminosity in 250 μm selected sources above what has been seen in previous analyses. In addition, we find evidence that 250 μm sources with warm dust SEDs have a larger 1.4GHz luminosity than the cooler sources in our sample. Though we find no evidence for redshift evolution of the monochromatic FIRC, our analysis reveals significant temperature dependence. Whilst the FIRC is reasonably constant with temperature at 100 μm, we find increasing inverse correlation with temperature as we probe longer PACS and SPIRE wavelengths. These results may have important implications for the use of monochromatic dust luminosity as a star formation rate indicator in star-forming galaxies, and in the future, for using radio data to determine galaxy star formation rates.

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  • A multi-modal device for application in microsleep detection

    Knopp, Simon James (2015)

    Doctoral thesis
    University of Canterbury Library

    Microsleeps and other lapses of responsiveness can have severe, or even fatal, consequences for people who must maintain high levels of attention on monotonous tasks for long periods of time, e.g., commercial vehicle drivers, pilots, and air-traffic controllers. This thesis describes a head-mounted system which is the first prototype in the process of creating a system that can detect (and possibly predict) these lapses in real time. The system consists of a wearable device which captures multiple physiological signals from the wearer and an extensible software framework for imple- menting signal processing algorithms. Proof-of-concept algorithms are implemented and used to demonstrate that the system can detect simulated microsleeps in real time. The device has three sensing modalities in order to get a better estimate of the user's cognitive state than by any one alone. Firstly, it has 16 channels of EEG (8 currently in use) captured by 24-bit ADCs sampling at 250 Hz. The EEG is acquired by custom-built dry electrodes consisting of spring-loaded, gold-plated pins. Secondly, the device has a miniature video camera mounted below one eye, providing 320 x 240 px greyscale video of the eye at 60 fps. The camera module includes infrared illumination so that it can operate in the dark. Thirdly, the device has a six-axis IMU to measure the orientation and movement of the head. These sensors are connected to a Gumstix computer-on-module which transmits the captured data to a remote computer via Wi-Fi. The device has a battery life of about 7.4 h. In addition to this hardware, software to receive and analyse data from the head-mounted device was developed. The software is built around a signal processing pipeline that has been designed to encapsulate a wide variety of signal processing algorithms; feature extractors calculate salient properties of the input data and a classifier fuses these features to determine the user's cognitive state. A plug-in system is provided which allows users to write their own signal processing algorithms and to experiment with different combinations of feature extractors and classifiers. Because of this flexible modular design, the system could also be used for applications other than lapse detection‒any application which monitors EEG, eye video, and head movement can be implemented by writing appropriate signal processing plug-ins, e.g., augmented cognition or passive BCIs. The software also provides the ability to configure the device's hardware, to save data to disk, and to monitor the system in real time. Plug-ins can be implemented in C++ or Python. A series of validation tests were carried out to confirm that the system operates as intended. Most of the measured parameters were within the expected ranges: EEG amplifier noise = 0.14 μVRMS input-referred, EEG pass band = DC to 47 Hz, camera focus = 2.4 lp/mm at 40 mm, and total latency < 100 ms. Some parameters were worse than expected but still sufficient for effective operation: EEG amplifier CMRR ≥ 82 dB, EEG cross-talk = -17.4 dB, and IMU sampling rate = 10 Hz. The contact impedance of the dry electrodes, measured to be several hundred kilohms, was too high to obtain clean EEG. Three small-scale experiments were done to test the performance of the device in operation on people. The first two demonstrated that the pupil localization algorithm produces PERCLOS values close to those from a manually-rated gold standard and is robust to changes in ambient light levels, iris colour, and the presence of glasses. The final experiment demonstrated that the system is capable of capturing all three physiological signals, transmitting them to the remote computer in real time, extracting features from each signal, and classifying simulated microsleeps from the extracted features. However, this test was successful only when using conventional wet EEG electrodes instead of the dry electrodes built into the device; it will be necessary to find replacement dry electrodes for the device to be useful. The device and associated software form a platform which other researchers can use to develop algorithms for lapse detection. This platform provides data capture hardware and abstracts away the low-level software details so that other researchers are free to focus solely on developing signal processing techniques. In this way, we hope to enable progress towards a practical real-time, real-world lapse detection system.

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  • Descriptions of coping with commonly occurring events by highly self-regulated boys living in earthquake-affected Christchurch

    Gillman, Solfrid Hessellund (2015)

    Masters thesis
    University of Canterbury Library

    Children are often overlooked in the aftermath of a natural disaster, and children’s use of coping strategies plays an important part in their post-disaster adaptation (Vernberg, La Greca, Silverman, & Prinstein, 1996). The aim of this qualitative study was to explore the coping strategies of children with adequate self-regulation skills and minimal behaviour problems, living in Christchurch following the major 2010 and 2011 earthquakes. This aim was achieved through the use of semi-structured interviews with five seven-year-old children, their parents, and their teachers. These interviews were analysed using Directed Content Analysis and results showed that children most often reported using active and adaptive coping strategies, followed by avoidant strategies. Results in the current literature regarding children’s coping suggest that children exposed to natural disasters are able to utilise strategies that involve some personal control over their environment and emotions, through the use of active and adaptive coping strategies. Findings from this study contribute to the current understanding of children’s use of coping strategies when faced with commonly occurring childhood upsets. Further research is required regarding the outcomes associated with the use of effective coping strategies following traumatic events.

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  • Geochemical variations in glauconitic minerals : application as a potassium fertiliser resource.

    Smaill, Joshua Ballantyne (2015)

    Masters thesis
    University of Canterbury Library

    Nutrients for plant growth are often limited in soil systems and additions are required in the form of fertiliser. Potassium is an essential macro-nutrient for plants and demands for K are expected to increase in the future. Glaucony is an abundant marine mineral which may provide an alternative K-rich fertiliser resource. The South Island of New Zealand contains deposits of glaucony-rich rocks which were deposited in the Early- to Mid-Cenozoic during periods of low sedimentation to the seafloor. Here, the geochemistry of glaucony from the Waitaki Basin (Otago), the Waipara Greensand (North Canterbury) and the Stoney Creek Limestone (Karamea) was examined using spatially resolved geochemical analysis and dissolution experiments. Grain-by-grain analysis using Laser Ablation Induction Coupled Plasma Mass Spectrscopy (LA-ICP-MS) and Scanning Electron Microscopy with Energy Dispersive Spectroscopy (SEM + EDS) revealed that glaucony from all deposits were of the mature type and were enriched in K. Glaucony derived from growth inside faecal pellets was found to contain elevated K and Fe concentrations compared to bioclast hosted glaucony. These variations can be explained by the physical properties of host grains and sea-floor redox conditions at the time of precipitation, both of which increased ionic mobility into the zone of glauconitisation. Solubility analysis showed that K^{+} was released from glaucony more rapidly than any other element. Additionally, decreasing the pH and introducing an oxidising agent (i.e, birnessite which is ubiquitous in soil environments) accelerated K^{+} release 13-fold. Trace metals including Cr, Zn, Cu and Ni were present in the solid phase analysis, however further investigation revealed that these elements were released into solution in low concentrations and may present a source of micro-nutrients, not a soil contaminant. These results suggest that glaucony may offer a source of slow releasing K fertiliser, and the South Island of New Zealand is ideally situated as a place to consider using glaucony as a locally sourced, environmentally sustainable K resource for agriculture.

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  • An Approach to Embedding ITSs into Existing Systems

    Amalathas, Sagaya Sabestinal (2012)

    Doctoral thesis
    University of Canterbury Library

    Intelligent Tutoring Systems (ITSs) have proven their effectiveness in many domains, but very few attempts have been made to embed them with existing systems. This area of research has a lot of potential in providing life-long learning and work place training. This PhD project makes several significant contributions. This is the first attempt to embed a Constraint-Based Tutor (CBT) with an existing system, in order to investigate the benefits of providing on-the-job training. We also propose a framework for embedded ITSs, and develop DM-Tutor (Decision-Making Tutor) embedded with the MIS for palm oil. DM-Tutor is the first ITS for the domain of oil palm plantation decision making, and was developed in the ASPIRE authoring system. Our hypothesis was that DM-Tutor embedded with the MIS for palm oil would provide effective instruction and training for oil palm plantation decision making. We also wanted to investigate the role of feedback messages in helping to provide effective training.

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  • Lesions of the Dorsal Medial Hippocampus induce different forms of Repetitive Behaviour in the rat

    Haq, Sahina (2015)

    Masters thesis
    University of Canterbury Library

    The dorsal dentate gyrus (DDG) of the hippocampus plays a role in the expression of different forms of flexible behaviour mainly due to its ability to sustain neurogenesis throughout life. In the present thesis, we examined the role that the DDG and its adjacent areas, both collectively referred to as dorsal medial hippocampus (DMH), play in flexible, adaptive behaviour and cognitive processing. We used the neurotoxin, colchicine, to induce lesions of the DDG, which were found to affect neighbouring areas. Thus these lesions will be referred to as lesions of the DMH. In the first experiment, rats were tested for (1) perseverative behaviour before and after receiving chronic methamphetamine (METH) treatment, (2) METH-induced locomotor activity and stereotypy in an open field, and (3) working memory in a T-maze. The results showed that rats with lesions of the DMH exhibited perseveration and supersensitivity to the locomotor- and stereotypy-inducing effects of METH (0, 0.1, 0.3, 1 mg/kg i.p.) as well as increased long-term METH sensitization. Rats with DMH lesions also showed significant working memory deficits. Taken together, these results reveal specific forms of behavioural inflexibility in rats with lesions of the DMH that are mainly associated with perseveration, drug-related behaviours, including stimulant motor supersensitivity and drug sensitization, and impaired working memory functions.

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  • Developing alternative SCDDP implementations for hydro-thermal scheduling in New Zealand.

    Read, Rosemary Anne (2014)

    Masters thesis
    University of Canterbury Library

    In a hydro-dominated system, such as New Zealand, the continual improvement and development of effective optimization and simulation software to inform decision making is necessary for effective resource management. Stochastic Constructive Dual Dynamic Programming (SCDDP) is a technique which has been effectively applied to the New Zealand system for optimization and simulation. This variant of Dynamic Programming (DP) allows optimization to occur in the dual space reducing the computational complexity and allows solutions from a single run to be formed as price signal surfaces and trajectories. However, any application of this method suffers from issues with computational tractability for higher reservoir numbers. Furthermore, New Zealand specific applications currently provide limited information on the system as they all use the same two-reservoir approximation of the New Zealand system. This limitation is of increasing importance with the decentralization of the New Zealand electricity sector. In this thesis we develop this theory with respect to two key goals: • To advance the theory surrounding SCDDP to be generalizable to higher reservoir numbers through the application of the point-wise algorithm explored in R. A. Read, Dye, S. & Read, E.G. (2012) to the stochastic case. • To develop at least two new and distinct two-reservoir SCDDP representations of the New Zealand system to provide a theoretical basis for greater flexibility in simulation and optimization of hydro-thermal scheduling in the New Zealand context.

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  • Moving beyond sustainability: To what extent does the Cradle to Cradle framework play a role within New Zealand's fashion industry?

    Dransfeld, Josephine Gisela (2015)

    Masters thesis
    University of Canterbury Library

    Our planet is threatened by a rapidly changing climate, alarming resource depletion and a steadily rising population growth. This calls for intensified sustainable practices within businesses of all sizes and industries. In recent years this resulted in a wholly new model called the circular economy. Inherent to this is the Cradle to Cradle framework which seeks to design and create commodities in such a way that the impact on the environment, i.e. the carbon footprint is neutralised. Significant efforts are currently being undertaken in Europe and the United States in various sectors with a recent focus on transforming the fashion industry. The literature finds that that there is generally still little known in this area, there was barely any evidence of this change taking in New Zealand. The objective of this research is to explore this and to eventually build a theoretical understanding to what extent Cradle to Cradle plays a role within the fashion industry. This was achieved by employing the grounded theory method. Data was collected by conducting semi-structured interviews with owners-managers supplemented by secondary data such as sustainability reports. In line with grounded theory principles, open and selective coding, theoretical sampling and constant comparison were used to analyse all data within the Nvivo 10 Software. The theory showed that somewhat severe resource constraints and an occurring loss of transparency by outsourcing manufacturing operations to overseas locations impede the shift towards the circular economy at present. This research contributes to sustainable development literature by providing a comprehensive model of how the uptake of sustainable practices is influenced and dependent on multiple aspects and therefore fosters the understanding of a complex, intertwined and intransparent industry. Furthermore, this research benefits companies and business networks alike.

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  • Safe, effective, and patient-specific glycaemic control in neonatal intensive care.

    Dickson, Jennifer Launa (2015)

    Doctoral thesis
    University of Canterbury Library

    Very premature infants often experience high blood sugar levels as a result of incomplete metabolic development, illness, and stress. High blood sugar levels have been associated with a range of worsened outcomes and increased mortality, but debate exists as to whether high blood sugar levels are a cause of, or marker for, these worsened outcomes. Insulin can be used to lower blood sugar levels, but there is no standard protocol for its use in neonates, and the few clinical studies of insulin use in neonatal intensive care are relatively small and/or have resulted in high incidence of dangerously low blood sugar levels. Hence, there is a need for a safe and effective protocol for controlling blood sugar levels to a normal range in order that potential clinical benefits can be successfully studied in this clinical cohort. This thesis adapted a glucose-insulin model successfully used in adult intensive care for the unique physiology and situation of the very premature infant. The model aims to reflect known physiology. As such, sources and disposal of glucose and insulin within the body are examined using both published data and unique data sets from a study here in New Zealand. In addition, the absorption of glucose from milk feeds is examined. This glucose-insulin physiological model is then used alongside statistical forecasting to develop a protocol for selecting an appropriate insulin dose based on targeting of likely outcomes to a specified target normal range. The protocol is tested in silico using virtual trials, and then clinically implemented, with results showing improved performance over current clinical practice and other published studies. In particular, ~77% of blood glucose is observed within the specified target range across the cohort, and there has been no incidence of dangerously low blood glucose levels. This protocol is thus safe and effective, accounting for inter- and intra- patient variability, and thus enabling patient-specific care.

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  • Usability Assessment of a Powered Wheelchair Controller: How Impairments Affect Human Computer Interaction Based Tasks

    Horne, Rory Michael (2015)

    Masters thesis
    University of Canterbury Library

    Problem: Designing the user experience is a growing trend in product design; however this trend has not greatly benefited people with impairments and disabilities. There are no practical tools to broadly assist with this issue. There is a need for standardized measures to quantify impairment, a model to predict how designs may perform and a need for data regarding how people with impairments interact with consumer technology. Purpose: To conduct a usability analysis with an industry partner on their powered wheelchair controller using participants with varying impairments. The industry partner was seeking better insight into the benefits of formal user testing. Method: Forty consenting adults were given a score representing their level of impairment using six measures from the International Classification of Functioning (ICF). These measures were identified by the researcher to affect interaction with a device. Performance was measured by time taken to complete tasks, errors made, reported task difficulty and reported controller usability. Results: Performance was reduced in participants with a higher ICF score and age. An ICF score less than or equal to 2 was 117 times more likely to not complete the tasks, greater than or equal to 3 was not able to complete the experiment. Age >50 years took an average 79 seconds longer than <35 years to complete a task and reported greater difficulty, more errors and a lower usability for the controller. Implications: Low to moderate levels of impairment has a significantly negative effect on the usability of common devices. Difficulties were mostly cognitive with participants unable to create an accurate mental model of the system. Participants with lower performance tended to be overly optimistic about their abilities. Mistakes were the greatest source of error followed by lapses and almost no reported or observed slip errors. Original Contribution: The ICF has never been used as a metric for usability testing. This study successfully applied the ICF alongside other measures to prove its validity. Based on the results and current literature the Task Process Model was created to provide a simple and practical way to describe the interaction of people completing a task of basic to moderate complexity.

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