The present work investigates, numerically, the process of melting and solidification in hollow vertical cylinders, filled with air and phase change material (PCM). The PCM used is sodium nitrate, which expands upon melting. Therefore, a void must be present within the cylinder, which is filled with air. The influence of cylinder shape on melting time is determined. The numerical model takes both conductive and convective heat transfer into account during the melting process. The Volume-of-Fluid (VOF) model is used to track the interface between the PCM and air as the PCM melts. Three dimensionless numbers represent the characteristics of the problem, which are the Grashof, Stefan, and Prandtl numbers. The Stefan and Prandtl numbers are held constant, while the Grashof number varies. Inner Aspect Ratio (AR) is used to characterize the shape of the cylinder, which is defined as the ratio of the height to the diameter of the vertical cylinder. In this study, a range of AR values from 0.23 to 10 is investigated. Cylinders with small AR, corresponding to high Grashof numbers, lead to lower melting times compared with cylinders with high AR. The molten PCM velocity was also influenced greatly by this difference between solid PCM shape between high and low AR cases. Cylinders with small AR, corresponding to high Grashof numbers, lead to higher solidification times compared with cylinders with high AR. It was found that the velocity decreased during the solidification process, but the shape of the cylinder had an effect on the decrease. Natural convection velocity was found to decrease during the solidification process and, therefore, its effects diminish as solidification proceeds.

Reliability issues are always salient as behavioral researchers observe human behavior and classify individuals from criterion-referenced test scores. This has created a need for studies to assess agreement between observers, recording the occurrance of various behaviors, to establish the reliability of their classifications. In addition, there is a need for measuring the consistency of dichotomous and polytomous classifications established from criterion-referenced test scores. The development of several log linear univariate models for measuring agreement has partially met the demand for a probability-based measure of agreement with a directly interpretable meaning. However, multi-variate repeated measures agreement produres are necessary because of the development of complex intrasubject and intersubject research designs. The present investigation developed applications of the log linear, latent class, and weighted least squares procedures for the analysis of multivariate repeated measures designs. These computations tested the model-data fit and calculated the multivariate measure of the magnitude of agreement under the quasi-equiprobability and quasi-independence models. Applications of these computations were illustrated with real and hypothetical observational data. It was demonstrated that employing log linear, latent class, and weighted least squares computations resulted in identical multi-variate model-data fits with equivalent chi-square values. Moreover, the application of these three methodologies also produced identical measures of the degree of agreement at each point in time and for the multivariate average. The multivariate methods that were developed also included procedures for measuring the probability of agreement for a single response classification or subset of classifications from a larger set. In addition, procedures were developed to analyze occurrences of systematic observed disagreement within the multivariate tables. The consistency of dichotomous and polytomous classifications over repeated assessments of the identical examinees was also suggested as a means of conceptualizing criterion-referenced reliability. By applying the univariate and multivariate models described, the reliability of these classifications across repeated testings could be calculated. The procedures utilizing the log linear, latent structure, and weighted least squares concepts for the purpose of measuring agreement have the advantages of (1)yielding a coefficient of agreement that varies between zero and one and measures agreement in terms of the probability that the observers' judgements will agree, as estimated under a quasi-equiprobability or quasi-independence model, (2)correcting for the proportion of "chance" agreement, and (3) providing a directly interpretable coefficient of "no agreement." Thus, these multivariate procedures may be regarded as a more refined psychometric technology for measuring inter-observer agreement and criterion-referenced test reliability.

The conceptualization of intimacy within adolescent romantic relationships has typically taken a linear approach: Adolescents experience initial romantic encounters within a group context and progress towards an exclusive dyadic dating relationship. This study uses a person-centered approach and conceptualizes adolescent romance as multi-dimensional.In Study 1, a large, nationally representative dataset (the National Longitudinal Study of Adolescent Health) was used to classify 10th and 11th grade adolescents into ideal romantic relationship styles via Latent Class Analysis. Four classed emerged: Concealers (3.6%; n=276), Abstainers (32.6%; n=2508), Engagers (51.4% of the sample; n= 3955), and Family Builders (12.5%; n=959). Concealers, primarily non-White ethnicities, preferred low social/emotional involvement but moderate sexual activities. Most adolescents with same-sex attractions were concealers. Concealers reported the greatest miss-match between ideal and real relationship activities. Abstainers, predominantly females, preferred: high social/emotional activities, to talk less about contraception/STDs, and low sexual activities. Engagers, predominantly male and White, scored highest on all social, emotional, and physical activities (exception of 'seeing less of friends', 'sex', 'pregnancy', and 'marriage'). Family builders, overly-represented by Latino, preferred high social, emotional, and physical dimensions including seeing less of friends, sexual intercourse, pregnancy, and marriage. Moderate discrepancies occurred between ideal and real activities.Study 2 was a focus group study of White and Latino adolescents (N=75) entering 10th through 12th grades. Using a symbolic interactionism theoretical framework, adolescents described four types of sexual relationships within their social subjective realities: Going-out, dating, friends with benefits, and hooking up. Going-out relationships, an exclusive and emotionally/physically close relationship, were the most easily described and the most intense and committed relationships. Dating relationships, however, were the most common type of sexual relationship and were less easily defined, partially due to the ambiguity of the relationship itself which is to 'get to know each other'. These relationships were somewhat exclusive and required less obligations. Friends with benefits (primarily physical relationships) and hooking up (single physical encounters) were casual relationships that required little to no commitment.Findings are interpreted via a developmental/feminist lens. Gender inequality and sexual double standards are potent forces that continue to shape adolescent's sexual behaviors, feelings, and experiences.

Sensible energy storage for solar domestic hot water (SDHW) systems is space consuming and heavy. Latent heat energy storage systems (LHESSs) offer a solution to this problem. However, the functionality of a LHESS during simultaneous charging/discharging, an operating mode encountered when used with a SDHW, had not been studied experimentally. A small scale vertical cylindrical LHESS, with dodecanoic acid as the phase change material (PCM), was studied during separate and simultaneous charging/discharging. Natural convection was found to have a strong influence during melting, but not during solidification. During simultaneous operation heat transfer was limited by the high thermal resistance of the solid PCM. However, when the PCM was melted, direct heat transfer occurred between the hot and cold heat transfer fluids, indicating the significance of the PCM phase on heat transfer in the system. The results of this research will lead to more optimally designed LHESS for use with SDHW. ?

The study aims to estimate the ability of different grouping techniques on categorical response. We try to find out how well do they work? Do they really find clusters when clusters exist? We use Cancer Problems in Living Scales from the ACS as our categorical data variables and lung cancer survivors as our studying group. Five methods of cluster analysis are examined for their accuracy in clustering on both real CPILS dataset and simulated data. The methods include hierarchical cluster analysis (Ward's method), model-based clustering of raw data, model-based clustering of the factors scores from a maximum likelihood factor analysis, model-based clustering of the predicted scores from independent factor analysis, and the method of latent class clustering. The results from each of the five methods are then compared to actual classifications. The performance of model-based clustering on raw data is poorer than that of the other methods and the latent class clustering method is most appropriate for the specific categorical data examined. These results are discussed and recommendations are made regarding future directions for cluster analysis research.

This thesis work presents a numerical study of the effects of fins and thermal fluid velocities on the storage characteristics of a cylindrical latent heat energy storage system (LHESS). The work consists of two main components: 1. The development of a numerical method to study and solve the phase change heat transfer problems encountered in a LHESS during charging of the system, which results in melting of the phase change material (PCM). The numerical model is based on the finite element method. The commercial software COMSOL Multiphysics was used to implement it. The effective heat capacity method was applied in order to account for the large amount of latent energy stored during melting of a PCM, and the moving interface between the solid and liquid phases. The fluid flow, heat transfer and phase change processes were all validated using known analytical solutions or correlations. 2. Due to the low thermal conductivity of PCMs, the heat transfer characteristics of an enhanced LHESS was studied numerically. The effects of fins and the thermal fluid velocity on the melting rate of the PCM in the LHESS were analyzed. Results obtained for configurations having between 0 and 27 fins show that the heat transfer rate increases with addition of fins and thermal fluid velocity. The effect of the HTF velocity was observed to be small with few fin configurations since the thermal resistance offered by the LHESS system, mostly PCM, is vastly more important under these conditions; while its effect becomes more pronounced with addition of fins, since the overall thermal resistance decreases greatly with the addition of fins. The total energy stored after 12 hours for 0 and 27 fins configurations range between 3.6 MJ and 39.7 MJ for a thermal fluid velocity of 0.05 m/s and between 3.7 MJ and 57 MJ for a thermal fluid velocity of 0.5 m/s. The highest system efficiencies for the 0.05 m/s and 0.5 m/s, obtained with 27 fins configuration are 68.9% and 97.9% respectively.

This work presents an experimental and numerical study of phase change behaviour in a horizontal cylindrical latent heat energy storage system (LHESS). Fins with two orientations, straight fins and angled fins, are added into the PCM to enhance heat transfer. The PCM used in this study is lauric acid which has desirable thermal properties for LHESS. The experimental work concentrates on studying the heat transfer mechanism during phase change, impacts of the HTF inlet temperature and HTF flow rates. Moreover, heat transfer enhancement effectiveness of straight fins and angles fins is compared. Numerical model is simulated using COMSOL Multiphysics software package. It is observed that conduction is the dominant heat transfer mechanism during the initial stage of charging, and natural convection plays a more important role afterwards. Conduction plays a major role during solidification. Complete melting time is affected by the HTF inlet temperature and HTF flow rates.

There may be several mechanisms that drive observed interactions between plants and pollinators in an ecosystem, many of which may involve trait matching or trait complementarity. Hence a model of insect species activity on plant species should be represented as a mixture of these linkage rules. Unfortunately, ecologists do not always know how many, or even which, traits are the main contributors to the observed interactions. This thesis proposes the Latent Dirichlet Allocation (LDA) model from artificial intelligence for modelling the observed interactions in an ecosystem as a finite mixture of (latent) interaction groups in which plant and pollinator pairs that share common linkage rules are placed in the same interaction group. Several model selection criteria are explored for estimating how many interaction groups best describe the observed interactions. This thesis also introduces a new model selection score called ``penalized perplexity". The performance of the model selection criteria, and of LDA in general, are evaluated through a comprehensive simulation study that consider networks of various size along with varying levels of nesting and numbers of interaction groups. Results of the simulation study suggest that LDA works well on networks with mild-to-no nesting, but loses accuracy with increased nestedness. Further, the penalized perplexity tended to outperform the other model selection criteria in identifying the correct number of interaction groups used to simulate the data. Finally, LDA was demonstrated on a real network, the results of which provided insights into the functional roles of pollinator species in the study region.

This thesis was to determine the prevalence and distribution of paratuberculosis in the Ontario dairy sheep and dairy goat industries, identify potential risk factors for herds which tested positive, evaluate the accuracy of seven commercially available individual and two bulk tank diagnostic tests in these two populations, and determine the circulating strains of Mycobacterium avium ssp. paratuberculosis in faecal isolates obtained. A cross-sectional study was conducted between October 2010 and August 2011 in 29 goat herds and 21 sheep flocks located in Ontario. On each farm, 20 lactating animals over the age of two years were randomly selected and faeces, blood, and milk were sampled from each animal, and a bulk milk sample from each herd. A questionnaire inquiring about herd management and biosecurity behaviours was also completed. The seven individual animal tests evaluated were: faecal culture using the BACTEC® MGIT™ 960 liquid culture system, direct faecal PCR (Tetracore®, Rockville, MD) based on the hspX gene, the Prionics® ELISA on serum and milk, the IDEXX® ELISA on serum and milk, and the agar gel immunodiffusion (AGID) test on serum. The test evaluations used both frequentist (faecal culture - reference test) and Latent Class Analysis/Bayesian (LCA/BM) methods (no reference test). In goat herds, faecal culture demonstrated the highest sensitivity (Se), 81.1% (LCA/BM). In sheep, while faecal culture demonstrated the highest Se, 49.5%, there was a small probability it was higher than faecal PCR Se at 42.4%. The bulk tank tests evaluated were the 'Hyper-ELISA' test and real-time PCR test based on IS900 (AntelBio®). While PCR did not demonstrate sufficiently high Se to be used as a herd-level test, the Hyper-ELISA performed well as a herd-level test identifying farms with high prevalence when the cut-off was reduced to 0.05. Overall herd-level apparent prevalence was 79.3% in goat herds and 57.1% in sheep flocks when faecal culture was the reference standard and true herd-level prevalence (LCA/BM) was 83.0% and 66.8% in each population respectively. This high prevalence reveals a need for the implementation of a small ruminant paratuberculosis control program in Ontario, Canada based on testing, improving youngstock management, and strengthening biosecurity practices. / AHSI, OMAF

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