In this thesis, the morphological changes of the anode surface in lithium sulphur cell, during early cycling, were simulated using symmetrical lithium electrode cells with dissolved polysulphides (PS) in the electrolyte. Electron microscopy (SEM) was used as the principal investigation technique to study and record the morphological changes. The resulting images from the SEM were analysed and discussed. The initial surface structure of the lithium anode largely influenced the ensuing morphological changes taking place through lithium dissolution (pits) and lithium deposition (dendrites) during discharge and charge respectively. The rate of lithium dissolution and deposition was found to be linearly proportional to the current density applied to the cell and the effect of cycling on the anode was proportional to the total charge of the cell in general in agreement with the expected reaction. The effect of self-discharge on the anode was also studied using photoelectron spectroscopy (XPS) in tandem with SEM. The results indicated that self-discharge, occurring in the form of corrosion of the anode SEI by PS reduction, was influenced by the altered morphology of the cell after cycling. The findings presented in this project can be understood as a preliminary description for the morphological changes in the anode and their influence in the performance of lithium sulphur battery, which can be further investigated by more advanced methods. / <p>Joint collaboration project between Scania CV AB and Uppsala University.</p>

The intent of this thesis was to study the effects of caffeine ingestion on substrate utilization and muscle metabolism during exercise, as reflected by endurance time to exhaustion. For this purpose, seven trained cyclists performed work bouts at 80% of maximal oxygen consumption to exhaustion after ingestion of caffeine (CAF trial) end under control (CON trial) conditions.Although the work time to exhaustion was not significantly different between the CAF trial, 91.8 (S.E. ± 7.7) min and the CON trial, 85.2 (S.E. ± 10.5) min, five of he subjected did show an average 18% increase in performance following ingestion of 330 mg caffeine. Since there was no elevation of FFA prior to exercise, it was expected that no muscle glycogen sparing would occur during the first 30', 41.7 (S.E. ± 6.1) mM/kg in the CAF trial and 42.1 (S .E. + 6.6) mM/kg in the CON trial. Serum glycerol concentration was significantly (P< .05) during the CAF trial at 10' and 30'. R values were significantly lower during the CAF trial, .87 (S.E. ± .01) than the CON trial, .91 (S.E. ± .01) at exhaustion. Significantly lower (p<.05) perceived exertion ratings were also observed during the CAF trial. These data suggest a positive effect on endurance exercise performance following caffeine ingestion.

Contemporary outreach services focus on prevention as a means to ending homelessness (Averill, Keys, Mallet, & Rosenthal, 2010; Gaetz, 2010; Higgitt, Ristock & Wingert, 2005). As a result, services are commonly aimed at youth to provide alternatives to street-life before negative patterns are ingrained; the emotional effects of homelessness are also starting to be addressed. Drop-in facilities are proving useful by responding with greater flexibility toward the inconsistent lives of homeless people (Bantchevska, Dashora, Garren, Glassman, Slesnick & Toviessi, 2008). Art programming offers an environment addressing both emotional concerns and technical skill development (Higgitt, Ristock & Wingert, 2005). In Winnipeg, MB, urban, youth street-culture has responded positively to drop-ins embodying Hip-Hop culture as the unifying theme (B. Veruela, personal communication, November 7, 2012). Hip-Hop provides a context for art and learning that incorporates belonging and growth - the identifiers of a playful space. Play spaces offer a positive environment for dealing with emotionally charged topics such as homelessness (Apter, 1991; Kerr, 1991). This project presents the adaptive reuse of one of Winnipeg’s industrial buildings as a modern drop-in centre where emotional care for youth is accommodated through play theory.

Obesity has become a worldwide problem that most countries are trying to fight. It affects many people, irrespective of age, race, gender, or religion; anyone can suffer from obesity, which leads to serious problems, both for individuals and for society as a whole. In this study we have selected two groups of people: the basic people who do not exercise on a weekly basis, and the average people who exercise regularly, every week. We have explored the attitude of the two groups in regards to mixing exercises with games, in order to motivate the people with basic activity levels to exercise more frequently. We have used a qualitative standard online questionnaire from AttrakDiff, which evaluates user experience through four important aspects: a) quality; b) subjective understanding of quality and subjective evaluation of quality; c) pragmatic and hedonic features; and d) emotional and behavioural effects. We also did a qualitative study and a quantitative study of some of the important factors present during exercise. The results of the qualitative and quantitative studies were very encouraging as they revealed that mixing games with exercise can transform boring exercises into entertaining ones. It can also motivate players to continue and repeat the exercises. The ANOVA test was applied and it shows that combining games with a stationary bike has a significant effect on the speed and the average rotation per minute of the participants.

Ohmic nanoswitches have been recently regarded to complement transistors in applications where electrical current leakage is becoming a problem. Although the solid state metal oxide silicon field effect transistor (MOSFET) has fueled a global technology revolution, it is now reaching its performance limits because of device leakage. To avoid electric field-induced damage in MOSFETs, operating voltage and hence threshold voltage must be reduced as linewidth is reduced. However, below a limit, the current cannot be turned off. The ohmic switch approach solves this problem because an air gap that separates the electrical contacts provides excellent electrical isolation when the relay is open. Some applications require these relays to perform billions to trillions of cycles, yet typical devices that are exposed to ambient environment degrade electrically after just a few thousand cycles. A critical challenge here is that trace amounts of volatile hydrocarbons in air adsorb on the electrical contact surfaces for a large variety of coating materials, causing an insulating deposit to form that prevents signal transmission during switch closure. We address this challenge by exploring the interactions of hydrocarbon contaminants with contact materials and operating environment on device lifetime. Our materials of choice are Pt, a common contact material in switch applications due to its resistance to wear, and RuO2, which is believed to be somewhat resistant to hydrocarbon adsorption. We test our devices in N2 and O2 background environments with controlled hydrocarbon contaminant concentrations. We illustrate that the insulating hydrocarbon deposit can be electrically broken down and its resistance lowered. We show how electrical contacts that have degraded electrically due to contamination can have their performance restored to the original level by actuating them in clean N2-O2 environment. It is then shown how this process creates a highly conductive carbonaceous deposit that protects the contact from wear. It is also v demonstrated that RuO2 does not exhibit contaminant-induced degradation even at very high hydrocarbon presence, as long as O2 is also present. These results show that even though the contaminant is ubiquitous in the environment, there are many ways to reduce its effect on ohmic switches.

Microbial activity occurs year-round in Arctic soils, including during the winter when soils are frozen. From 2004 to 2008 I monitored soil microbial and nutrient dynamics in low Arctic wet and dry sedge meadows near Churchill, Manitoba. I documented a consistent annual pattern in which soil microbial biomass (MB) and soil nutrients peak in late winter, and decrease during the early stages of spring thaw, remaining in low abundance during the summer. Based on a series of experiments, resource shortages do not appear to be the cause of the microbial decline, as has been hypothesized. Observations and theoretical considerations regarding soil physical properties indicate that this decrease is driven by the influx of liquid water at thaw that brings about a rapid change in the chemical potential of water, leading to cell lysis. I have used 15N isotope tracing to show that inorganic nitrogen is taken up very quickly at thaw by the roots of the dominant plant, Carex aquatilis. This represents a critical window of opportunity for these plants, as nitrogen remains abundant only for a short time. The described annual pattern was pronounced in wet sedge sites, but some inter-annual variation is evident, for example a post-thaw soil nitrogen pulse in 2006, and low winter MB in 2008. In the dry sedge meadow, fluctuations in MB and nutrients were dampened relative to wet sites, and the annual pattern was variable, particularly after 2006. Over four years, peak winter values of soil MB and nutrient variables declined in both wet and dry sites, and this could be related to a drying trend. This work improves our understanding of the controls on decomposition and primary productivity in a system that is experiencing climate warming and increased precipitation. Changes to hydrology, carbon and nitrogen cycling, and primary productivity will have further effects on vegetation communities and higher trophic levels, including several species of migratory birds.

The purpose of this study was to examine the effects of recovery modes and exercise durations on blood lactate concentrations and subsequent performance in cycling tests. Fourteen male subjects completed six randomly assigned experimental protocols with a combination of three durations and two modes of recovery (passive and active cycling at 45% VO$ sb{ rm 2 max}$). Each protocol consisted of eight bouts of cycling at 120% of VO$ sb{ rm 2 max}$ interspersed with five minute recovery periods. Each protocol terminated with a maximal performance task consisting of a 45s all-out cycling test. Results indicated significantly (p $<$ 0.05) higher blood lactate concentrations in the passive and 60s conditions. Mean power outputs measured in the performance task were significantly (p $<$ 0.05) higher in the active recovery conditions compared to passive recovery. Mean power outputs were lower during the 60s conditions. Since the correlation between blood lactate and mean power output was low (r = -0.24), other factors were influencing subsequent performance.

Blood lactate concentration and mean power output were examined over a series of maximal intermittent exercise bouts with varying recovery patterns. Thirteen elite male cyclists completed four randomly assigned experimental conditions. Each exercise/recovery condition consisted of twelve 10 s maximal exercise bouts on a Monark cycle ergometer. Four different recovery patterns (30, 60, 90 and 120 s) followed the repeated 10 s all-out efforts. Results revealed that the mean power output averaged over the 12 trials was 12.7, 13.0, 13.2 and 13.4 W/kg, for the 30, 60, 90 and 120 s conditions, respectively. Blood lactate concentration during exercise were 9.9, 9.2, 6.5 and 6.0 mmol/1, for the 30, 60, 90 and 120 s conditions, respectively. The 30 and 60 s conditions yielded significantly lower mean power output values compared to the 90 and 120 s conditions. Following the repeated maximal 10 s efforts, blood lactate concentration was significantly greater in the 30 and 60 s recovery conditions compared to the 90 and 120 s conditions.

The statistics from the US Department of Energy show that about one-third of the total consumption of electricity in the households and industries is due to the Air Conditioning and Refrigeration (AC & R) systems. This wide usage has prompted many researchers to develop models for each of the components of the vapor compression systems. However, there has been very little information on developing simulation models that have been validated for the conditions of start-up/shutdown operations as well as vapor compression system faults. This thesis addresses these concerns and enhances the existing modeling library to capture the transients related to the above mentioned conditions. In this thesis, the various faults occurring in a vapor compressor cycle (VCC) have been identified along with the parameters affecting them. The transients of the refrigerant have also been studied with respect to the start-up/shutdown of a vapor compression system. All the simulations related to the faults and start-up/shutdown have been performed using the vapor compression system models developed in MATLAB/Simulink environment and validated against the 3-ton air conditioning unit present in the Thermo-Fluids Control Laboratory at Texas A & M University. The simulation and validation results presented in this thesis can be used to lay out certain rules of thumb to identify a particular fault depending on the unusual behavior of the system thus helping in creating certain fault diagnostic algorithms and emphasize the importance of the study of start-up/shutdown transient characteristics from the point of actual energy efficiency of the systems. Also, these results prove the capability and validity of the finite control volume models to describe VCC system faults and start-up/shutdown transients.

Cross-sectional studies have shown that well trained endurance athletes frequently have a lower peripheral and central chemoreceptor response (pRc and cRc) and a lower minute ventilation (Ve) during exercise compared to untrained individuals. Some recent prospective studies support these observations. We speculated that the reductions in chemoreceptor response and Ve may be the specific result of the high rates of ventilation occurring during endurance training. To test this idea, subjects performed voluntary eucapnic hyperpnea to simulate exercise hyperpnea while avoiding the metabolic consequences of physical exercise. We therefore examined the effects of respiratory muscle training (RMT: 20x30min sessions of voluntary eucapnic hyperpnea) on the pRc, cR, cycling performance, and Ve. Twenty endurance trained cyclists were randomized into RMT or control-groups. To indicate cRc both the hypercapnic ventilatory response at rest (HCVRr) and during light exercise (HCVRex) were measured in a background of 50% O2. The pRc was assessed by measuring the ventilatory response to a modified Dejours O2 test (4-6 trials of 10-12 breaths of 100% O2) during light exercise. Endurance performance and Ve were measured during a fixed-rate cycling endurance test, performed at 85% of the maximal workload until exhaustion. The RMT-group's cycling endurance improved significantly compared to controls (+3.26±4.98min versus -1.46±3.67min. p=0.027) but Ve was unchanged at all times analyzed. The pRc was significantly reduced in the RMT-group but unchanged in controls (-5.8±6.0% versus +O.1±4.6%, p=O.032). The cRc, both at rest and during exercise, was not significantly altered following RMT in either group. However, the X-intercept of HCVRex exhibited a significant shift to the left (-5.83±10.68mmHg, +O.38±2.48mmHg, p=O.047, RMT-group and controls respectively). The importance of this leftward shift and the reduced pRc, though statistically significant, is unclear because there were no significant changes in Ve during any test nor were there correlations between Ve or performance or the altered chemoreceptor responses. We conclude that exercise hyperpnea, as simulated by RMT in this study, is accompanied by a reduction in pRc and a leftward shift in the HCVRex, and improves cycling endurance; however, the altered chemoreceptor responses had little impact on Ve suggesting that their role in the control of ventilation during exercise is minor.