Mg2Si-based thermoelectrics are currently the most promising, environmentally benign and inexpensive materials for power generation. The objective of this thesis is to characterize Mg2Si-based thermoelectric materials using state-of-the-art synchrotron radiation techniques including infrared reflectivity/absorption spectroscopy and high resolution X-ray powder diffraction. This is complemented by density functional theory (DFT) calculations. Also reported here is the main research: the analysis of the electronic structure and transport properties of doped Mg2Si using experimental and theoretical methods. To enhance the thermoelectric performance, Mg2Si doped with a single component of Bi or Sb were studied. The investigation showed by doping the electron carrier concentrations were increased. In particular, dc conductivities of the doped samples were extracted from the analysis of infrared reflectivity spectra employing the Drude free electron model. We found the conductivity was lower when determined by infrared measurements rather than in-situ four point probe measurements of the bulk sample because of the limited penetration depth of infrared (IR) radiation and the very small spot size. In particular, we were able to extract the electrical conductivity, relaxation times and electron effective masses of the samples. DFT calculations reproduced the experimental observations and show a substantial increase in the Seebeck coefficients. The next step was to study the effect after doping with two different dopants. For this purpose, we investigated the effect of Ge substitute Si in Bi doped Mg2Si. In particular, the dc conductivities of the doped samples were extracted from the analysis of infrared reflectivity spectra. From the IR data, we extracted the relevant parameters for electrical transport. The experimental data were explained with theoretical DFT calculations in which the calculated densities of states (DOS) of the Ge- and Bi-doped Mg2Si samples were found to be very similar, and therefore to have comparable Seebeck coefficients. The steep curvatures of the DOS at the Fermi level indicate a light electron band. We found the thermal conductivity of Mg2Si is substantially lower from 7 Wm-1K-1 to 2.7 Wm-1K-1 in Mg2Si0.677Ge0.3Bi0.023 at 300 K. A performance figure of merit of 0.7 was achieved at 773 K for this sample. We further investigated the effect of multi-doping with Sb, Al and Zn on the enhancement of the thermoelectric and electrical transport properties of Mg2Si. A maximum ZT of 0.964 was found for Sb0.5%Zn0.5% doped Mg2Si (Mg1.995Zn0.005Si0.995Sb0.005) at 880 K. This value is comparable to those of PbTe based thermoelectrics which are the currently the materials used in commercial products. We also studied the effect of pressure on the thermoelectric performance of a Al-doped Mg2Si sample. From in-situ X-ray diffraction, we observed a structural transform in which the electrical conductivity was increased after the phase transition. The experimental observed maximum thermoelectric power at 1.9 GPa was reproduced by DFT calculations and explained by the increase of electronic density of states at the Fermi level. The effect of multi-wall carbon nanotubes (MWCNTs) to increase the electrical conductivity of Mg2Si0.877Ge0.1Bi0.023 was examined. At 323 K the conductivity was found to increase from 450 Ω-1cm-1 to 500 Ω-1cm-1. However, this effect diminished at higher temperature and the conductivity drop to 470 Ω-1cm-1 at 773 K. Raman study showed the persistent of disorder (D) and tangential (G) mode characteristics of a carbon nanotube in the doped sample indicating that there was no decomposition or substantial chemical reaction of the MWCNTs with Mg2Si0.877Ge0.1Bi0.023. Finally, we present the results on the analysis of valence electron topologies of Mg2Si multi-doped with Al, Zn and Sb thermoelectric materials by the Maximum Entropy Method (MEM) using data obtained from synchrotron X-ray powder diffraction measurements. The results showed the qualitative feature of valence electron distributions were correctly located. However, due to the limited number of Bragg diffraction peaks in the experimental patterns, the effect of the dopants to the core charge density cannot be reliably obtained. An error analysis was performed from the analysis of diffraction pattern of Al-doped Mg2Si which included high angle Bragg reflections. We concluded that the density maps extracted from MEM analysis of the doped samples were qualitatively correct.

Mechanical Ventilation (MV) therapy is one of the most common treatments offered to patients with respiratory failure in ICU. MV assists patient recovery by completely or partially taking over the breathing process and helping with oxygen delivery and removal of carbon dioxide. However, inappropriate MV settings mismatched to a given patient’s condition can cause further damage. On the other hand, suboptimal MV settings can increase the length of stay of the patient in ICU and increase the cost of treatment. Acute Respiratory Distress Syndrome (ARDS) is a major form of Acute Lung Injury (ALI) where clinicians offer a supportive environment for patient recovery by application of MV. ARDS is characterised by inflamed and fluid filled lungs that result in alveolar collapse and thus severe hypoxemia. Application of positive end expiratory pressure (PEEP) is employed to recruit and retain lung units to maximise gas exchange. However, a delicate trade-off is required between maximising gas exchange and preventing further unintended damage to the lungs, when determining optimum PEEP level. Currently, no specific protocols to determine optimum PEEP level exist and selection of PEEP is dependent on medical intuition and experience, primarily due to lack of easy methods to determine patient – specific condition at the patient’s bedside. A mathematical recruitment model is developed in Labview to help determine patient – specific condition based on fundamental lung physiology and engineering principals in this thesis. The model utilises readily available clinical data to determine parameters that identify underlying patient – specific lung characteristics and conditions. Changes in these parameters can be monitored over time and compared between patients to determine the severity of the disease and evolution of disease with time. A second model is developed to determine dynamic functional residual capacity (dFRC), that represents the extra volume retained in a lung through application of PEEP. The model extends previous efforts in the field that applied the stress – strain theory to lung mechanics to estimate dFRC. This model estimates the patient’s dFRC using readily available clinical data (PV data) and can be monitored over time to determine changes in a xiii given patient’s condition. The dFRC model introduces a new parameter, , which is considered a population constant for the particular PEEP. The model offers an easy and reliable method to determine dFRC since other methods are normally invasive or require interruption of MV. The models developed were validated against real – time clinical data obtained through clinical trials. The recruitment model was found to fit the clinical data well with error values within acceptable limits. It also enabled identification of parameters that reflect the underlying patient – specific lung condition. The dFRC model was able to estimate the dFRC for a patient with high level of accuracy for clinically applicable PEEP levels. The two models work well in conjunction with each other and provide a novel and easy method to clinicians to determine patient – specific lung characteristics and ultimately determine optimal MV treatment parameters, especially PEEP.

Most species of reptile studied to date have polygynandrous mating systems and possess specialised sperm storage regions. Consequently, there is a high potential for sperm competition in this group. Using comparative analyses, I examined the level of sperm competition in New Zealand geckos and how this has influenced the evolution of their reproductive morphology. Across lizards and snakes, there was more than a 40-fold variation in relative testis size. New Zealand geckos fell in the middle of this range and lacked sexual dimorphism in head size, suggesting that most species have polygynandrous mating systems. I confirmed this for one species, Hoplodactylus maculatus, which is gregarious, lacks territoriality and has a courtship pattern that suggests a high level of promiscuity for both sexes. I found that hemipenis size in New Zealand geckos was positively correlated with relative testis size, suggesting that sperm competition has resulted in the evolution of larger intromittent organs. However, the surface features of the hemipenis were relatively conservative across species. Although there was no relationship between sperm length or putative sperm storage site (SST) morphology and relative testis size, species with fewer SSTs, and thus more intense sperm competition, had longer sperm. H. maculatus males produced two types of sperm which differed not only in length but also in fertilising capacity, the short morph lacking DNA. This is the first known example of such sperm polymorphism in a vertebrate and may have evolved in response to sperm competition, the non-fertilising morph potentially helping to block the sperm of rival males or filling sperm storage sites. The motility of these short sperm was positively correlated with temperature; however, at higher temperatures motility declined with time, suggesting a trade-off between motility and longevity. Such temperature influences on male reproductive physiology have important implications for males of ectothermic species under sperm competition.

There have been numerous attempts for measuring viticulture potential. In most cases, this involves the construction of a climate/viticulture based model which is then applied to a potential region. Although these climatic based models may perform well inside their original regions, they tend to fail elsewhere. Discrepancies between climatic indexes have been attributed to many factors including vineyard management, grapevine variety, phenology/climate misconceptions and regional macro/mesoclimate regimes. The aim of this study is to investigate the viticulture potential within two regions of the South Island of New Zealand, by implementing several climatic based models. These models have been designed to improve the predictive accuracy over other current climatic/viticulture models. A GIS, along with climatic data collected from over 80 stations within Canterbury and the surrounding region, are incorporated into several models which are used within this project as viticultural tools to improve the current understanding between topographic, climatic and grapevine relationships. Viticulture potential ratings are then assessed for two overlapping regions; the smaller sub-region of the lower Waipara catchment and the larger Canterbury region. Results show that many of the current vineyard plots in the Canterbury and lower Waipara regions do not fall within the optimal limits of the models, while there are large potential areas in both regions yet to be utilized for viticulture. However, not all of Canterbury and the lower Waipara catchment can be used for viticulture due to several limiting factors such as elevation, risk of frosts and low mean temperatures. Surprisingly, most of the Canterbury Plains fall within this 'no go' area. The model has proved to be a much more reliable tool than other existing climatic indexes such as the widely used degreeday and mean temperature of the warmest month indices.

Peroxyacetic acid was evaluated in four separate trials for ability to reduce populations of Escherichia coli O157:H7 and Salmonella serotype Typhimurium (ATCC 13311) on fresh beef trim. Trial 1 examined the effectiveness of peroxyacetic acid on individual pieces of fresh beef trim. Trial 2 was performed to evaluate the effectiveness of peroxyacetic acid at low levels of contamination on batches of trim. Trial 3 studied the washing effect of the dip due to water. Lastly, Trial 4 compared the effectiveness of peroxyacetic acid to lactic acid. At various inoculation levels, peroxyacetic acid reduced populations of rifampicin-resistant E. coli O157:H7 and S. Typhimurium by approximately 1.0 log CFU/cm2. Much of the reductions recorded in Trials 1 and 2 may have been due to the washing effect of the dip. Trial 3 showed that approximately half of the reduction was due to the water dip. In addition, as shown in Trial 1, increases in concentrations (> 200 ppm) did not significantly increase log reductions of rifampicin-resistant E. coli O157:H7 and S. Typhimurium. Following a water dip in Trial 4, peroxyacetic acid caused a reduction of 0.7 log CFU/cm2 in E. coli O157:H7 and 1.0 log CFU/cm2 in S. Typhimurium, whereas lactic acid caused reduction of 1.3 log CFU/cm2 in E. coli O157:H7 and 2.1 log CFU/cm2 in S. Typhimurium following the water dip. Peroxyacetic acid was not more effective than 2% L-lactic acid in reducing pathogens on fresh beef trim.

The general purpose of this study was to examine the spelling of five phonemes that are similar in Acehnese and Indonesian but represented by different graphemes in the two languages. This study aimed to see whether the exposure to the spoken Acehnese the participants? received helps or hinders their spelling in the Acehnese words. The Indonesian language is the national language of Indonesia while the Acehnese language is a regional language spoken by the people in a province named Aceh which is located in the northwestern tip of Sumatra Island, Indonesia. In Aceh, the majority of the population is bilingual in Indonesian and Acehnese. In the school system, Indonesian is taught as the first language. Acehnese is taught as a second language in elementary and junior high schools. Meanwhile, some children in Aceh speak Acehnese at home while other children speak Indonesian at home. Therefore, this study hypothesized that the children who speak Acehnese at home spell better in Acehnese compared to the children who do not speak Indonesian at home. To test the hypothesis, this study analyzed the 50 Acehnese words that include five targeted Acehnese graphemes. The participants of this study were students in grade 4 who were enrolled in four elementary schools in Aceh, Indonesia. The results of this study indicate that the exposure to spoken Acehnese interferes with the participants? spellings in Acehnese words. On the other hand, exposure to the written Acehnese the students received in school influenced the students to spell better in Acehnese.

Three ejaculates from each of eight stallions were initially centrifuged in INRA 96 extender and spermatozoal pellets were resuspended in a milk/egg yolk-based freezing extender or an egg yolk-based freezing extender. Extended semen was exposed to a fast pre-freeze cooling rate (FAST - semen immediately subjected to cryopreservation) or a slow pre-freeze cooling rate (SLOW - semen pre-cooled at a controlled rate for 80 minutes prior to cryopreservation). After thawing, semen was diluted in initial freezing medium (FM) or INRA 96 prior to analysis of 9 experimental endpoints: total motility (MOT; %), progressive motility (PMOT; %), curvilinear velocity (VCL; um/sec), average-path velocity (VAP; ?m/sec), straight-line velocity (VSL; ?m/sec), linearity (LIN; %), intact acrosomal and plasma membranes (AIVIAB; %), intact acrosomal membranes (AI; %), and intact plasma membranes (VIAB; %). Eight of nine experimental endpoints (MOT, PMOT, VAP, VSL, LIN AIVIAB, AI, and VIAB) were affected by extender type, with LE extender yielding higher values than MF extender for these variables (P<0.05). Exposure of extended semen to a slow pre-freeze cooling period resulted in increased values for seven of nine endpoints, as compared to a fast pre-freeze cooling period (P less than 0.05). Mean VAP and VSL were unaffected by prefreeze cooling rate (P>0.05). As a post-thaw diluent, INRA 96 yielded higher mean values than FM for MOT, PMOT, VCL, VAP, and VSL (P less than 0.05). Treatment group FM yielded slightly higher values than INRA 96 for LIN and VIAB (P less than 0.05). Extender x rate interactions (P less than 0.05) were detected for the variables MOT, AIVIAB, AI and VIAB. Mean values for these endpoints were higher following spermatozoal exposure to a slow pre-freeze cooling period, regardless of freezing extender type (P less than 0.05). The effects of pre-freeze cooling rate on MOT, AIVIAB, AI, and VIAB were more pronounced in spermatozoa cryopreserved in MF extender, as compared to LE extender. Within treatment groups SLOW and FAST, mean MOT, AIVIAB, AI, and VIAB were higher (P less than 0.05) for spermatozoa cryopreserved in LE extender, as compared to MF extender. Extender x diluent interactions (P less than 0.05) were detected for MOT, PMOT, VCL, VAP, VSL, and LIN. Within Group MF, mean MOT, PMOT, VCL, VAP, and VSL were higher in INRA diluent, as compared to FM diluent (P less than 0.05). Within Group LE, FM diluent yielded slightly higher values than INRA diluent for PMOT, VAP, VSL, and LIN (P less than 0.05). In conclusion, a slow pre-freeze cooling rate was superior to a fast pre-freeze cooling rate, regardless of freezing extender used, and INRA 96 served as a satisfactory post-thaw diluent prior to semen analysis.

N/A

Peroxyacetic acid was evaluated in four separate trials for ability to reduce populations of Escherichia coli O157:H7 and Salmonella serotype Typhimurium (ATCC 13311) on fresh beef trim. Trial 1 examined the effectiveness of peroxyacetic acid on individual pieces of fresh beef trim. Trial 2 was performed to evaluate the effectiveness of peroxyacetic acid at low levels of contamination on batches of trim. Trial 3 studied the washing effect of the dip due to water. Lastly, Trial 4 compared the effectiveness of peroxyacetic acid to lactic acid. At various inoculation levels, peroxyacetic acid reduced populations of rifampicin-resistant E. coli O157:H7 and S. Typhimurium by approximately 1.0 log CFU/cm2. Much of the reductions recorded in Trials 1 and 2 may have been due to the washing effect of the dip. Trial 3 showed that approximately half of the reduction was due to the water dip. In addition, as shown in Trial 1, increases in concentrations (> 200 ppm) did not significantly increase log reductions of rifampicin-resistant E. coli O157:H7 and S. Typhimurium. Following a water dip in Trial 4, peroxyacetic acid caused a reduction of 0.7 log CFU/cm2 in E. coli O157:H7 and 1.0 log CFU/cm2 in S. Typhimurium, whereas lactic acid caused reduction of 1.3 log CFU/cm2 in E. coli O157:H7 and 2.1 log CFU/cm2 in S. Typhimurium following the water dip. Peroxyacetic acid was not more effective than 2% L-lactic acid in reducing pathogens on fresh beef trim.

The primary aim of this study was to compare levels of cognitive anxiety for a group of first-time hearing aid users and their significant other before, during, and after hearing aid fitting. Secondary goals included: (1) comparing levels of cognitive anxiety for participants and their significant others at the same intervals, (2) assessing possible effects of gender on the experience of cognitive anxiety, (3) comparing the levels of cognitive anxiety for participants who adopted hearing aids and those that did not, and (4) identifying themes relating to the experience of hearing impairment and consultation for services. Thirty-nine adults between the ages of 30 and 87 years of age with and without hearing impairments participated in several interviews. Cognitive anxiety was measured using the Cognitive Anxiety Scale (CAS) by Viney & Westbrook (1976), which is a content analysis, grounded in personal construct psychology. The following research questions have been addressed: 1a) Do cognitive anxiety levels change in individuals with hearing impairment as they go through the consultation process? 1b) Is there any difference in cognitive anxiety levels between male and female participants with hearing impairment as they go through the consultation process? 2a) Do cognitive anxiety levels change in normal hearing significant others of individuals with hearing impairment as they go through the consultation process? 2b) Is there any difference in cognitive anxiety levels between male and female significant others as they go through the consultation process? 3a) Do cognitive anxiety levels differ between participants with hearing impairment who adopt amplification and those who do not? 3b) Do cognitive anxiety levels of significant others differ between participants with hearing impairment who adopt amplification and those who do not? Results revealed reduced cognitive anxiety levels for hearing impaired adults between the first interview and third interview, between the second interview and third interview, but no significant difference was found between the first interview and second interview. Furthermore, for significant others, CAS scores were significantly higher at interview 2 compared to interview 3, but no significant difference was found between interview 1 and interview 3, or between interview 1 and interview 2. Additionally, no significant differences in levels of cognitive anxiety were found between hearing impaired adults and significant others in the adopter and non-adopter group, and no gender differences were observed between hearing impaired adults and significant others. This study illustrates how important it is to involve the significant other in the consultation progress. However, due to a small sample size most analyses were underpowered therefore more research is needed to investigate cognitive anxiety levels in hearing impaired adults and their significant others.