Thermoelectric modules are an important alternative to heat engines in the harvesting of waste heat. Electrical-thermal analogues are often employed when studying heat conduction and this analogue can be extended to develop an equivalent circuit for thermoelectric effects. For the primarily one-dimensional problem of thermoelectricity, the equations can be discretized to create a simple mathematical model. In this document, such a model is developed from first principles and show that the electro-thermal coupling is properly in- corporated. The results of simulations using the model are then presented and validated experimentally. Furthermore, in one possible application of thermoelectric modules, a self-contained cooling unit with an integrated thermoelectric generator is designed. By performing fluid dynamics simulations on a fan and heat sink model, the geometry and operating conditions can be optimized and the start-up and transient characteristics are studied.

Bioalcohols, such as bioethanol and biobutanol, are suitable replacements for gasoline, while biodiesel can replace petroleum diesel. Improving biofuel engine performance requires understanding its fundamental combustion properties and the pathways of combustion. This study's contribution is experimentally validated chemical kinetic combustion mechanisms for biobutanol and biodiesel. Fundamental combustion data and chemical kinetic mechanisms are presented and discussed to improve our understanding of biofuel combustion. The net environmental impact of biobutanol (i.e., n-butanol) has not been studied extensively, so this study first assesses the sustainability of n-butanol derived from corn. The results indicate that technical advances in fuel production are required before commercializing biobutanol. The primary contribution of this research is new experimental data and a novel chemical kinetic mechanism for n-butanol combustion. The results indicate that under the given experimental conditions, n-butanol is consumed primarily via abstraction of hydrogen atoms to produce fuel radical molecules, which subsequently decompose to smaller hydrocarbon and oxygenated species. The hydroxyl moiety in n-butanol results in the direct production of the oxygenated species such as butanal, acetaldehyde, and formaldehyde. The formation of these compounds sequesters carbon from forming soot precursors, but they may introduce other adverse environmental and health effects. Biodiesel is a mixture of long chain fatty acid methyl esters derived from fats and oils. This research study presents high quality experimental data for one large fatty acid methyl ester, methyl decanoate, and models its combustion using an improved skeletal mechanism. The results indicate that methyl decanoate is consumed via abstraction of hydrogen atoms to produce fuel radicals, which ultimately lead to the production of alkenes. The ester moiety in methyl decanoate leads to the formation of low molecular weight oxygenated compounds such as carbon monoxide, formaldehyde, and ketene, thereby reducing the production of soot precursors. The study concludes that the oxygenated molecules in biofuels follow similar combustion pathways to the hydrocarbons in petroleum fuels. The oxygenated moiety's ability to sequester carbon from forming soot precursors is highlighted. However, the direct formation of oxygenated hydrocarbons warrants further investigation into the environmental and health impacts of practical biofuel combustion systems.

Bioalcohols, such as bioethanol and biobutanol, are suitable replacements for gasoline, while biodiesel can replace petroleum diesel. Improving biofuel engine performance requires understanding its fundamental combustion properties and the pathways of combustion. This study's contribution is experimentally validated chemical kinetic combustion mechanisms for biobutanol and biodiesel. Fundamental combustion data and chemical kinetic mechanisms are presented and discussed to improve our understanding of biofuel combustion. The net environmental impact of biobutanol (i.e., n-butanol) has not been studied extensively, so this study first assesses the sustainability of n-butanol derived from corn. The results indicate that technical advances in fuel production are required before commercializing biobutanol. The primary contribution of this research is new experimental data and a novel chemical kinetic mechanism for n-butanol combustion. The results indicate that under the given experimental conditions, n-butanol is consumed primarily via abstraction of hydrogen atoms to produce fuel radical molecules, which subsequently decompose to smaller hydrocarbon and oxygenated species. The hydroxyl moiety in n-butanol results in the direct production of the oxygenated species such as butanal, acetaldehyde, and formaldehyde. The formation of these compounds sequesters carbon from forming soot precursors, but they may introduce other adverse environmental and health effects. Biodiesel is a mixture of long chain fatty acid methyl esters derived from fats and oils. This research study presents high quality experimental data for one large fatty acid methyl ester, methyl decanoate, and models its combustion using an improved skeletal mechanism. The results indicate that methyl decanoate is consumed via abstraction of hydrogen atoms to produce fuel radicals, which ultimately lead to the production of alkenes. The ester moiety in methyl decanoate leads to the formation of low molecular weight oxygenated compounds such as carbon monoxide, formaldehyde, and ketene, thereby reducing the production of soot precursors. The study concludes that the oxygenated molecules in biofuels follow similar combustion pathways to the hydrocarbons in petroleum fuels. The oxygenated moiety's ability to sequester carbon from forming soot precursors is highlighted. However, the direct formation of oxygenated hydrocarbons warrants further investigation into the environmental and health impacts of practical biofuel combustion systems.

This dissertation addresses forward and inverse modeling of Rayleigh waves for near surface investigation. Results were obtained by imaging abandoned mine openings using Rayleigh waves in the laterally inhomogeneous medium. The efficient staggered grid stencil method to solve elastic wave equations using 2-D finite difference technique is presented. This numerical scheme is used to conduct a series of parametric studies on the propagation of Rayleigh waves. The first parametric study was conducted on a flat layered model of increasing and decreasing velocity with depth. A Rayleigh waves dispersion curve is found to be sensitive on a layer’s depth up to half of the minimum wavelength of Rayleigh waves. The phase velocity in the dispersion curve of Rayleigh waves is inversely and directly proportional to the frequency, depending on velocity increase or decrease with depth. The parametric study was carried out by introducing dipping layers in the model with increasing dip. The front (near the shot point) and back (at the end of receiver line) shot records are different if the subsurface contains dip. Dispersion is observed in near offset for down dip and in the far offset for up dip, computed from front and back shots respectively. Finally, a parametric study looked at subsurface anomalies with different shapes and sizes as well as their material properties. A Rayleigh wave is sensitive to very high material contrast and very low material contrast of the anomaly from it surrounding medium. The presence of a low material contrast anomaly from the surrounding medium traps the energy which causes reverberation. A Rayleigh wave is sensitive to an anomaly which is placed within the depth between one-third to half of minimum wavelength of Rayleigh wave from the surface. In order to resolve lateral heterogeneity, a new method is developed in this research which allows localization of the multichannel record in different panels. The dispersion curve of Rayleigh waves is computed in each panel using the slant stack technique. On the basis of parametric studies, an innovative inversion algorithm has been developed to minimize the error norm; ”the sum of the squares of the difference of reference and model dispersion curves” in an iterative way using a Very Fast Simulated Re-annealing (VFSR) technique.

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The studies in this dissertation aim at advancing our scientific understandings about physical processes involved in the aerosol-cloud-precipitation interaction and quantitatively assessing the impacts of aerosols on the cloud systems with diverse scales over the globe on the basis of the observational data analysis and various modeling studies. Long-term impacts of aerosols on precipitation and lightning over the Pearl River Delta megacity area in China are identified through the analysis of seven-year measurements of precipitation, lightning flashes, and visibility from 2000 to 2006. The cloud resolving - Weather Research and Forecasting (CR-WRF) model with a two- moment bulk microphysical scheme is employed to simulate a mesoscale convective system in the Guangzhou megacity area and to elucidate the effects of aerosols on cloud processes, precipitation, and lightning activity. The responses of hydrometeors and latent heat release to different aerosol loadings reveal the physical mechanism for the precipitation and lightning enhancement in the Guangzhou megacity area, showing more efficient mixed phase processes and intensified convection under the polluted aerosol condition. Sensitivity modeling experiments are performed for maritime warm stratocumulus clouds over the southeast Pacific Ocean to evaluate the microphysical parameterizations for simulations of the aerosol effects in regional and global climate models. The Morrison double-moment bulk microphysical scheme presently implemented in the WRF model is modified by replacing the fixed aerosols in the original bulk scheme with a prognostic double-moment aerosol representation to predict both aerosol number concentration and mass mixing ratio. The impacts of the parameterizations of diffusional growth and autoconversion of cloud droplets and the selection of the embryonic raindrop radius on the performance of the bulk microphysical scheme are also evaluated. The impacts of Asian pollution outflows on the Pacific storm track are assessed utilizing reanalysis data, a hierarchical modeling approach and the multi-scale aerosol- climate modeling frame. Statistical analysis of two sets of reanalysis data suggests a strengthened trend of the storm track intensity over the North Pacific since 1979. The two-month seasonal simulations using a CR-WRF model with a two-moment bulk microphysics are performed to examine the aerosol effects on the Pacific storm track intensity. Subsequently, the anomalies of the diabatic heating rate by the Asian pollution outflow derived from the CR-WRF simulations have been prescribed in the NACR Community Atmosphere Model (CAM5) to provide the aerosol forcing terms. The forced GCM well reproduces an enhancement in the intensity of storm track, compared to the unforced model simulations. Similarly, under the multi-scale aerosol-climate modeling frame, the comparisons of the simulated present day versus pre-industrial climate corresponding to two different aerosol scenarios indicate the increased precipitation and poleward heat transport for the present-day climate reveal invigorated mid-latitude cyclones. The current work illustrates the complexity of the aerosol effects on the cloud systems at the diverse scales with different meteorological conditions. This study also stresses the importance of accurate representation of aerosol forcings in the different types of atmospheric numerical models for future climate projections.

The objective of this dissertation was to advance the knowledge about mathematics instruction regarding the use of exploratory graphical embodiments in Pre-K to College levels. More specifically, the study sought to find out which graphical representations generate the highest learning effect sizes as well as which teaching method is the most supportive when graphical representations are applied. The dissertation is organized into three coherent research studies that correspond to different schooling levels. The primary method of data analysis in this study was meta-analysis supported by synthesis of qualitative and comparative studies. A total of 73 primary studies (N = 9055) from 22 countries conducted over the past 13 years met the inclusion criteria. Out of this pool, 45 studies (N = 7293) were meta-analyzed. The remaining 28 studies (N = 1762) of qualitative or mixed method designs where scrutinized for common themes. The results support the proposed hypothesis that visualization aids mathematics learning. At the primary level, the mean effect size for using exploratory environment was ES = 0.53 (SE = 0.05, 95% CI: 0.42-0.63), the mean effect size for using computerized programs at the grade levels 1-8 was ES = 0.60 (SE = 0.03, 95% CI: 0.53-0.66), and the results of applying congruent research techniques at the high school and college levels revealed an effect size of ES = 0.69 (SE = 0.05, 95% CI: 0.59–0.79). At each of the teaching level, implementing an exploratory environment generated a moderate effect size when compared to traditional teaching methods. These findings support a need for a broader implementation of exploratory learning media to mathematics school practice and provide evidence to formulate a theoretical instructional framework.

Antifreeze proteins (AFPs) protect organisms from freezing damage at subzero temperatures. They do this by adsorbing to the surface of nascent ice crystals to block further ice growth. The key property of AFPs is to be soluble in liquid water but bind irreversibly to water in the solid state. Hypotheses for the mechanism by which AFPs recognize and bind ice have gone through several radical revisions without a consensus emerging. The remarkable diversity of independently evolved AFP structures, the multiple ice planes bound by AFPs, and uncertainty about the location of the ice-binding site(s) have all added to the difficulty of deducing a unified mechanism of AFP action. The central thesis of my research is that the characterization of additional AFPs will elucidate rather than obfuscate the mechanism of action. To this end I have advanced knowledge about three hyperactive AFPs. A reliable protocol to express and purify a sufficient quantity of type I hyperactive AFP was developed for further characterization studies. Initial crystallization trials using the recombinant material have produced consistent crystals for diffraction and resolution. A model of the recently discovered snow flea AFP was generated via de novo methods. The folding scheme is polyproline type II helices stacked into anti-parallel sheets, which was to our knowledge previously unobserved in monomeric proteins. The model was subsequently confirmed to be within 1 Å accuracy by X-ray crystallography performed by another group. I have also screened several insects for antifreeze activity. By using mass-spectrometry sequencing and a cDNA library, novel AFPs (3 kDa and 8kDa) were discovered from overwintering inchworms. The translated proteins were subsequently de novo modelled. After a thorough analysis of the literature, I reason that conflicting results from various AFP studies can be resolved. The hydrogen-bond ice-binding hypothesis was re-introduced to work coherently with elements of the hydrophobic ice-binding theory. We have proposed a unifying mechanism termed “anchored clathrate water,” which is supported by the water bonding on ice-binding surfaces reported both in in silico and in NMR studies. The new data I have obtained have further reinforced and expanded the hypothesis. / Thesis (Ph.D, Biochemistry) -- Queen's University, 2011-04-15 14:54:55.315

A model is developed to describe the bulk thermally-initiated free-radical polymerization of styrene between 100 °C and 170 °C. This model incorporates a comprehensive thermal initiation mechanism including generation and consumption of a Diels-Alder adduct intermediate species. A semi-empirical break-point treatment of diffusion control on reaction kinetics is used to account for autoacceleration behaviour. Using recently-developed statistical techniques, parameters are ranked based on their influence on model predictions, uncertainty in their initial values and correlation between their effects. The four top-ranked parameters (of the 40 total model parameters) are chosen for estimation to improve the fit between model predictions and literature data. After estimation of these four parameters, and hand-tuning of two additional autoacceleration parameters, the model predicts conversion data with a standard error of 5 %. The model also provides an excellent fit to a single MWD curve obtained from a literature experiment performed at 100 °C. Simulations are used to show that chain-end degradation reactions are not important in the temperature range of interest. The model is then extended to include industrially-relevant dicumyl peroxide and biphenyl peroxide chemical initiation. Additional peroxide-induced mid-chain scission reactions are considered as they may have an important influence on the molecular weight of polystyrene. To improve trends in predictions of Mn and Mw, the stationary-state hypothesis is applied to the initial adduct concentration. Parameters are then ranked, and selected for estimation using recently-developed statistical techniques. While significant improvements in predictions of conversion data are obtained, it is necessary to manually tune several parameters and scrutinize the reaction scheme in detail. To improve trends in predictions of Mn and Mw, mid-chain scission reactions are turned off and chain-transfer to monomer is implemented. Nine of the 48 total parameters are selected for estimation, resulting in a 73 % decrease in the objective function value compared with predictions using literature values. The final step of this work will be to estimate parameters using a large, proprietary industrial data set. Using this data set, it may be possible to estimate additional parameters which may lead to improved model predictions. / Thesis (Master, Chemical Engineering) -- Queen's University, 2012-02-22 12:43:35.531

Articular cartilage accrual occurs predominantly during childhood and adolescence, with the magnitude, direction, and pattern of internal joint loads directing the cartilage growth. If any of these factors of the joint loading are abnormal, it can predispose these children to degenerative knee joint disease as an adult. To provide an estimate of the internal joint loads, a paediatric-focused, static optimization-based lower limb model was developed, compared to recorded sEMG, and analyzed for sensitivity to changes in ground reaction force and muscle attachment site. The model was found to provide consistent predictions of joint contact force predictions ranging from 0.01 to 0.35xBW with standard error of 8% to 17%, with the exception of left knee medial-lateral shear at 108%. Muscle force predictions related well to sEMG, with the standard error ranging from 14% to 36%, except for gastrocnemius lateral at 104%. The model was sensitive to variations in the ground reaction force vector, with a maximum deviation of 0.11 xBW determined as a result of a ±5% variation in GRF. The model was found to be sensitive to clinically relevant deviations in muscle attachment site. Maximum knee anterior shear was significantly changed (p < 0.05) with a 1cm posterior quadriceps insertion deviation, maximum lateral shear with a posterior semimembranosus deviation, and maximum medial shear with a posterior or medial quadriceps deviation. No deviations caused statistically significant changes in compression. Statistically significant change in joint contact force could not be predicted based on changes in muscle moment arm, but could be indirectly predicted by the predicted muscle forces. The model’s uniform convergence and sensitivity to variations in input indicate that the model is sufficiently reliable and robust. This sensitivity suggests that the model is capable of adapting to altered loading conditions and musculoskeletal geometry, either due to deformity or corrective procedure. The model was therefore deemed to be a strong platform for developing clinically specific models for analyzing internal knee loads in a diverse paediatric population. / Thesis (Master, Rehabilitation Science) -- Queen's University, 2012-09-26 10:37:20.752