<p> This thesis investigates the characteristics of noise generation in the gas wiping process, including the effects of the various parameters manipulated in the process and countermeasures used to reduce noise levels. The process of gas wiping is used in many industrial applications such as drying of pulp and paper, photograph production and some high performance cooling applications. One of the most important industrial applications of gas wiping is the production of hot-dipped galvanized sheet steel. Gas wiping is a very efficient and reliable process to control coating thickness and uniformity of galvanized steel products, and can be used for very high line speeds and production rates. Changing the various process parameters such as the jet to strip distance (z), the jet slot width (h), plenum pressure (P) and jet inclination angle (α) allows manufacturers to control the coating thickness and quality of the finished product.</p> <p> The gas wiping process is also responsible for the generation of very high levels of noise, which can be a factor in limiting the overall production rates and indirectly increase production costs for manufacturers. To maintain a constant coating thickness as the line speed and production rate is increased, the plenum pressure supplied to the jets and thus the incident jet velocity must be increased, or the jet-to-strip distance must be decreased. Noise production in the gas wiping process is acknowledged to be proportional to the incident jet velocity and inversely proportional to the jet-to-strip distance. Thus, for a given coating thickness, as the production rates increase, the noise generated by the process must also increase. Ergonomic restrictions in the workplace, which limit the exposure to high sound pressure levels and audible acoustic tones, may indirectly limit the maximum line speed for a steel sheet with a given coating thickness. This limitation is particularly relevant to the production of high quality automotive sheet steels, which often have very thin coating thicknesses and have higher than normal coating uniformity tolerances, which necessitate the use of high plenum pressures and small jet-to-strip distances.</p> <p> At present, the state of knowledge for noise generation in the gas wiping process is very limited. Only two previous investigations have been devoted to this problem, and the experiments for these studies have only modeled specific individual cases, with no attempt at a comprehensive modeling of noise in this process. For the current study, measurements have been performed in both an actual manufacturing environment and on a scaled galvanizing simulator in a laboratory environment. A comprehensive set of experiments over a wide range of gas wiping parameters was performed in order to provide a broad overview of noise generation in the gas wiping process and allow for process optimization to reduce noise and allow higher production rates and efficiency. The creation of noise maps, modeling the overall sound pressure level and tone intensity for gas wiping as function of the various operating parameters of the process, as well as a set of equations and models to determine the frequency of discrete acoustic tones are presented. A full analysis of the frequency response, as well as the acoustic modes generated in various jet impingement regions has also been provided.</p> / Thesis / Master of Applied Science (MASc)

The primary contribution of this thesis is the development of a new performance metric, Capacity, which evaluates the performance of Chip Heterogeneous Multiprocessors (CHMs) that process multiple heterogeneous channels. Performance metrics are required in order to evaluate any system, including computer systems. A lack of appropriate metrics can lead to ambiguous or incorrect results, something discovered while developing the secondary contribution of this thesis, that of workload modes for CHMs — or Workload Specific Processors (WSPs). For many decades, computer architects and designers have focused on techniques that reduce latency and increase throughput. The change in modern computer systems built around CHMs that process multi-channel communications in the service of single users calls this focus into question. Modern computer systems are expected to integrate tens to hundreds of processor cores onto single chips, often used in the service of single users, potentially as a way to access the Internet. Here, the design goal is to integrate as much functionality as possible during a given time window. Without the ability to correctly identify optimal designs, not only will the best performing designs not be found, but resources will be wasted and there will be a lack of insight to what leads to better performing designs. To address performance evaluation challenges of the next generation of computer systems, such as multicore computers inside of cell phones, we found that a structurally different metric is needed and proceeded to develop such a metric. In contrast to single-valued metrics, Capacity is a surface with dimensionality related to the number of input streams, or channels, processed by the CHM. We develop some fundamental Capacity curves in two dimensions and show how Capacity shapes reveal interaction of not only programs and data, but the interaction of multiple data streams as they compete for access to resources on a CHM as well. For the analysis of Capacity surface shapes, we propose the development of a demand characterization method in which its output is in the form of a surface. By overlaying demand surfaces over Capacity surfaces, we are able to identify when a system meets its demands and by how much. Using the Capacity metric, computer performance optimization is evaluated against workloads in the service of individual users instead of individual applications, aggregate applications, or parallel applications. Because throughput was originally derived by drawing analogies between processor design and pipelines in the automobile industry, we introduce our Capacity metric for CHMs by drawing an analogy to automobile production, signifying that Capacity is the successor to throughput. By developing our Capacity metric, we illustrate how and why different processor organizations cannot be understood as being better performers without both magnitude and shape analysis in contrast to other metrics, such as throughput, that consider only magnitude. In this work, we make the following major contributions: • Definition and development of the Capacity metric as a surface with dimensionality related to the number of input streams, or channels, processed by the CHM. • Techniques for analysis of the Capacity metric. Since the Capacity metric was developed out of necessity, while pursuing the development of WSPs, this work also makes the following minor contributions: • Definition and development of three foundations in order to establish an experimental foundation — a CHM model, a multimedia cell phone example, and a Workload Specific Processor (WSP). • Definition of Workload Modes, which was the original objective of this thesis. • Definition and comparison of two approaches to workload mode identification at run time; The Workload Classification Model (WCM) and another model that is based on Hidden Markov Models (HMMs). • Development of a foundation for analysis of the Capacity metric, so that the impact of architectural features in a CHM may be better understood. In order to do this, we develop a Demand Characterization Method (DCM) that characterizes the demand of a specific usage pattern in the form of a curve (or a surface in general). By doing this, we will be able to overlay demand curves over Capacity curves of different architectures to compare their performance and thus identify optimal performing designs. / Ph. D.

This descriptive, survey research study was conducted using a quantitative, non-experimental, correlational, research design. Given the ever-increasing numbers of students taking online learning courses both before and during the COVID-19 pandemic, this study sought to explore this phenomenon by measuring the levels of online graduate student preceived connectedness at Virginia Tech. Bolliger and Inan (2012), validated their Online Student Connectedness Survey (OSCS) instrument in a research study that focused only on connectedness, and was limited to just one subject area, computer engineering. Permission was granted for the use of their OSCS instrument for this study, and the focus was expanded to include various subject areas, and to explore the associations between graduate student peceived connectedness and graduate student perceived learning and retention. Specifically, this study sought to find out whether there were indicators that an association existed between graduate student perceived connectedness and graduate student perceived learning and retention across the different modes of online learning (e.g., asynchronous, synchronous, and blended asynchronous/synchronous). The total sample for this research study was comprised of 67 research participants (32 males and 35 females), and their modes of online learning were asynchronous (n = 22), synchronous (n = 30), and blended asynchronous/synchronous (n = 15). Results indicated no statistically significant differences in graduate student perceived connectedness across the three online learning modes. There was a statistically significant association between graduate students' level of perceived connectedness and graduate student perceived learning and retention. As the level of graduate student perceived connectedness rose, so did graduate student perceived learning and retention. Furthermore, the results revealed that there were no statistically significant differences in the levels of graduate student perceived connectedness across the two types of online courses (e.g., pandemic online learning courses and regular online learning courses). This indicated that at Virginia Tech online graduate students felt connected whether they were in a pandemic online learning course or a regular online learning course. / Doctor of Philosophy / This survey research study was conducted using a quantitative, non-experimental, research design. Given the ever-increasing numbers of students taking online learning courses both before and during the COVID-19 pandemic, this study sought to explore this phenomenon by measuring the levels of online graduate student preceived connectedness at Virginia Tech. Bolliger and Inan (2012), verified their Online Student Connectedness Survey (OSCS) instrument in a research study that focused only on connectedness, and was limited to just one subject area, computer engineering. Permission was granted for the use of their OSCS instrument for this study, and the focus was expanded to include various subject areas, and to explore the associations between graduate student peceived connectedness and graduate student perceived learning and retention. Specifically, this study sought to find out whether there was an association between graduate student perceived connectedness and graduate student perceived learning and retention across the asynchronous, synchronous, and blended asynchronous/synchronous learning platforms. The total sample for this research study was 67 research participants (32 males and 35 females), and there were 22 asynchronous participants, 30 synchronous participants, and 15 blended asynchronous/synchronous participants. Results indicated no significant differences in graduate student perceived connectedness across the three online learning modes. There was a significant association between graduate students' level of perceived connectedness and graduate student perceived learning and retention. As the level of graduate student perceived connectedness rose, so did graduate student perceived learning and retention. Furthermore, the results revealed that there were no significant differences in the levels of graduate student perceived connectedness across the two types of online courses (pandemic online learning courses and regular online learning courses). This indicated that at Virginia Tech online graduate students felt connected whether they were in a pandemic online learning course or a regular online learning course.

A number of issues associated with the generation and applications of localized waves are addressed in this thesis. First, the salient characteristic features of two canonical localized wave solutions to the scalar wave equation are discussed. Second, novel azimuthally polarized focus wave mode-type and X wave-type localized electromagnetic fields are derived using a vector-valued spectral approach. Third, all reported experiments dealing with the generation of localized waves are discussed and a concise report on field depth measurements, together with practical implications, is presented. Fourth, new methods for generating X waves in the microwave frequency regime are proposed. Emphasis is placed on increasing the field depth. The proposed new feed scheme increases the field depth as much as 10 times compared to the experimental results reported by Mugnai et al. [2000]. Two modified reflector systems are introduced for the generation of X waves. The first uses an offset launcher reflector configuration. The second uses a Cassagrain reflector system with an integrated circular slit. Finally, future work on electromagnetic X wave generation by means of independently addressable array elements is discussed. / Master of Science

Optical resonators, which confine light by resonant recirculation, serve as the basis for a wide variety of optical components. Though they appear in many geometric forms, the most effective of optical resonators show axial symmetry in at least one dimension. A popular variation that finds broad application is the dielectric sphere. Acclaimed for their high quality (Q) factor and small modal volume, spheres owe credit of these attractive features to their support of whispering gallery mode (WGM) resonances. The sensitivity of a resonance's frequency and Q to strain, temperature, and other parameters of the surrounding medium can be the basis for ultracompact modulators and sensors. Physically, WGMs are special optical modes which can be understood as light rays that orbit the equator of the sphere guided by total internal reflection. Like a smooth stone can be skipped along the surface of a pond, light can be confined to the inside of a sphere by successive reflections. To best excite WGMs, the source light should initially trace a line tangent to the sphere's circumference. But incorporating a tiny sphere with such nanometric tolerances into a practical sensor structure has its challenges and the prospects for microsphere applications have suffered because of the plight of this problem. The work in this dissertation details the fabrication and function of three new "press fit" spherical resonators. These etched fiber micro-devices were developed to meet the demand for a robust, self-integrated means of coupling light between an optical fiber and WGMs in a microsphere resonator. The etching processes have been tuned to enable secure storage of a microsphere while also providing efficient excitation and interrogation of WGMs. Furthermore, the methods have been designed to be staightforward, quick, and repeatable. Using standard etchants on common polarization-maintaining fiber with readily purchased microspheres, the press fit resonators demonstrated here can be batch-fabricated and assembled. The press fit spherical resonator offers an alignment-free and conveniently pigtailed WGM coupler that has great potential for bio-science sensing applications and studies of resonant bispheres. / Ph. D.

This dissertation describes the simulation and optimization of adsorptive and chromatographic separation processes. The first part focus on the simulation and comparison of operational modes in simulated moving bed (SMB) chromatography for separation and purification in bioprocesses. The second part includes the simulation of gas-phase adsorptive processes by pressure swing adsorption and temperature swing adsorption technologies. The applications of SMB chromatography are popular in separating and purifying enantiomers, petrochemicals, pharmaceuticals and biochemicals with higher yield and lower solvent consumption. We simulate and compare several operational modes of simulated moving bed (SMB) for a binary and a ternary bioprocess using Aspen Chromatography. These operational modes are able to improve the separation efficiency of the basic SMB process by our simulation and optimization. We compare their separation performances and identify heuristics that will guide the selection of operational modes across a variety of systems. Pressure swing adsorption (PSA) and temperature swing adsorption (TSA) are two of the main technologies for gas-phase adsorption separation processes. We simulate and demonstrate a PSA model for air separation system and a TSA model for CO2 capture system in Aspen Adsorption. We present their separation performance plots to provide the physical insights of these two systems. / Ph. D.

An increase emphasis has been placed on the automotive industry to develop advanced technology vehicles which meet increasing strict government regulations and standards for emissions and fuel economy while maintaining the safety, performance, and consumer appeal of the vehicle. In response to these requirements, hybrid and electric vehicle technologies have become more complex as the necessity for vehicles with an overall better environmental impact. Modern engineers must understand the current methods used to analyze and evaluate risk with the new hybrid technologies to ensure the continued customer satisfaction and safety while meeting new government and agency standards. The primary goal of this work is to maintain consistent definitions, standards, and protocols for risk analysis using design failure modes and effects analysis. Throughout the entire automotive sector there exist standards for risk analysis and methods for analysis, however these models can be difficult to relate to the atmosphere under which educational competitions occur. The motor system case study within this work aims to allow the process for DFMEA to be simple and easily implemented and understood when it is appropriate to start. After defining the model, an electric motor system for hybrid vehicle is analyzed for mechanical and inverter system risks. The end result being a 32% reduction in motor system risk due to recommended actions for mitigating top motor systems risks for future motor system design and implementation, all to meet customer requirements. This work aims to provide an additional tool that when implemented will accelerate the next generation of automotive engineers. / Master of Science

Column-supported embankments (CSE) enable accelerated construction on soft soils, high performance, and protection of adjacent facilities. The foundation columns transfer embankment and service loading to a competent stratum at depth such that loading on the soft soil can be reduced. This has the beneficial effects of reducing settlement and lateral displacement, and improving stability. Selection of column type depends on the design load, cost, constructability, etc., although unreinforced concrete columns are commonly used. A load transfer platform (LTP) is often included at the embankment base. This is a layer of coarse-grained fill that may include one or more layers of geosynthetic reinforcement. The LTP improves vertical load transfer to columns by mobilizing the shear strength of the LTP fill and the membrane effect of the geosynthetic. The geosynthetic reinforcement also responds in tension to lateral spreading. Herein, lateral spreading is defined as the lateral displacements occurring in response to lateral earth pressures in the embankment and foundation. Excessive lateral spreading can lead to bending failure of the concrete columns, tensile failure of the geosynthetic reinforcement, and instability of the system. Design procedures recommend inclusion of geosynthetic reinforcement to mitigate lateral spreading, with assumptions for the lateral thrust distribution, failure mode, and calculation of geosynthetic tensile capacity. The necessity and sufficiency of these assumptions have not been fully validated. In addition, unreinforced concrete columns have low tensile strength and can fail in bending, but recommendations for calculating column bending moments are not available. This research examines the limitations in CSE lateral spreading design with the goal of advancing fundamental understanding of lateral spreading mechanics. The research was performed using three-dimensional finite difference analyses. Limiting conditions for lateral spreading analysis were identified using case history records, and an undrained-dissipated approach was validated for the numerical analysis of limiting conditions (i.e., undrained end-of-construction and long-term excess pore pressure dissipated). The numerical model was calibrated using a well-documented case history. Additional analyses of the case history were performed to examine the lateral earth pressures in the foundation, column bending moments, and geosynthetic contribution to resisting lateral spreading. A parametric study was conducted to examine the lateral thrust distribution in 128 CSE scenarios. A refined substructure model was adopted for analyzing peak geosynthetic tensions and strains. Lastly, failure analyses were performed to examine the effect of different CSE design parameters on embankment failure height, failure mode, and deformations. The research produced qualitative and quantitative information about the following: (1) the percent thrust resistance provided by the geosynthetic as a function of its stiffness; (2) the geosynthetic contribution to ultimate and serviceability limit states; (3) the change in lateral thrust distribution throughout the embankment system before and after dissipation of excess pore water pressures; (4) the column-soil interactions involved in embankment failure; and (5) identification of two failure modes in the undrained condition. Design guidance based on these findings is provided. / Doctor of Philosophy / Column-supported embankments (CSEs) have been designated by the Federal Highway Administration as a critical technology for new highway alignment projects and widening of existing highways. CSEs enable accelerated construction and high performance in weak soils, which are factors critical to project success. In a CSE, columns are installed in the weak soil, followed by rapid construction of the soil embankment that provides the necessary elevation and foundation for the roadway. The columns transfer most of the embankment and traffic loading to a competent soil stratum at depth. Concrete without steel reinforcement is commonly used to construct the columns, although material selection depends on cost, constructability, expected load, etc. Layers of geosynthetic reinforcement can also be included at the embankment base. The geosynthetics help to transfer loads to the columns and resist excessive movement that could lead to instability. The entire embankment system should be designed for safety and economy. This research was motivated by uncertainties in design to mitigate lateral spreading. Lateral spreading refers to lateral displacements occurring in response to lateral earth pressures in the embankment and foundation. Excessive lateral spreading can lead to failure of the columns, geosynthetic reinforcement, and the entire embankment system. This research aims to advance fundamental understanding of lateral spreading in CSEs and to re-evaluate current design assumptions. Corresponding design guidance is provided.

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal. / Notre étude porte sur l'évolution des modes de vie des jeunes au Canada entre le début des années 80 et la fin des années 90 et prolonge une recherche déjà réalisée par Dominique Meunier, Paul Bernard et Johanne Boisjoly en 1995. Cette dernière portait sur l'évolution des modes de vie des jeunes Canadiens durant les années 80. En prolongeant l'analyse jusqu'à la fin des années 90, nous avons cherché à savoir comment s'articulent, depuis les 20 dernières années, les liens que les jeunes entretiennent avec les études, avec le travail rémunéré et avec les différents modes de cohabitation, afin de cerner les principaux modes de vie qui caractérisent leur entrée dans l'âge adulte. Nous avons aussi cherché à connaître les principales différences entre l'évolution des modes de vie des femmes et des hommes. En plus de chercher à re-vérifier, pour une période plus récente, les hypothèses de Meunier, Bernard et Boisjoly, soit celle d'un retardement dans l'atteinte des seuils d'entrée dans la vie adulte, celle d'une désynchronisation de ces seuils et celle d'une atténuation des différences entre les parcours masculins et féminins, nous avons élaboré une autre hypothèse, qui rend bien compte de la nouvelle configuration structurelle de la jeunesse. Nous avons en effet mis de l'avant le fait que depuis les 20 dernières années, le contexte de précarité qui domine l'ensemble des processus d'intégration sociale et professionnelle a contribué à faire passer la jeunesse d'un état de passage à celui d'espace. De plus, nous avons voulu insister sur le caractère « sélectif » de l'espace jeunesse, où différences et inégalités agissent pour trier les jeunes et les acheminer vers l'âge adulte. En somme, l'essentiel de notre principale hypothèse de recherche consistait à dire que la jeunesse est véritablement scindée à la fin des années 90; elle est le lieu d'une polarisation, où certains sont avantagés et d'autres pas. Non seulement les jeunes n'appartiennent pas aux même milieux sociaux, mais ils ne naissent pas non plus dans un même contexte socio-économique et historique. Des facteurs de classe, d'origine sociale et de contexte créent nécessairement des inégalités au sein de la jeunesse, inégalités qui se manifestent dans la capacité des jeunes à sortir de la dépendance caractéristique de l'adolescence. Nous avons aussi émis l'hypothèse de la poursuite de l'atténuation des différences entre les hommes et les femmes, se traduisant essentiellement par une plus grande place faite aux jeunes femmes dans le marché du travail. Afin de vérifier la validité de nos hypothèses, nous avons utilisé les données de l 'Enquête sur les finances des consommateurs, que Statistique Canada mène annuellement auprès d'environ 80 000 personnes. Cette enquête nous a procuré des informations sur les trois grandes dimensions à partir desquelles l'entrée dans la vie adulte est cernée: les rapports de cohabitation, les rapports aux études et les rapports au travail rémunéré. Les résultats de nos analyses indiquent que la jeunesse comme espace précaire est l'objet d'une double polarisation à la fin des années 90. Chez les jeunes « plus vieux », âgés de 25 à 34 ans, bien que la majorité soit établie à la fois au plan professionnel et au plan résidentiel, une proportion croissante présente toujours certaines caractéristiques de la dépendance. De plus en plus de ces « vieux » jeunes manifestent de la difficulté à s'extirper complètement de la jeunesse. Cette difficulté se traduit par une insertion précaire et fragile dans le marché du travail, par une cohabitation prolongée avec la famille d'origine ou encore par l'obligation de partager les frais domestiques quotidiens avec d'autres personnes -la colocation-, des personnes avec qui ils n'entretiennent pas de liens conjugaux. Chez les jeunes « plus jeunes », âgés de 15 à 24 ans, la tendance principale est à la scolarisation accentuée. Ces « jeunes » jeunes mettent de plus en plus le cap sur les études, non seulement comme priorité mais comme activité exclusive. Ils adoptent une stratégie qui, certes, les maintient plus longtemps dans un état de dépendance face à leurs parents, mais qui tend à réduire les effets négatifs de l'adoption de statuts dits « hybrides ». Alors qu'une proportion croissante de « vieux » jeunes semblent souffrir des stratégies adoptées antérieurement, les «jeunes» jeunes ont majoritairement adopté une stratégie différente pour tenter de mettre les chances de leur côté. Les résultats de nos analyses nous indiquent aussi que bien des femmes de plus de 25 ans connaissent une trajectoire nouvelle : ayant, au cours de la décennie 1980-1990, massivement accru leur présence à l'école, elles prennent, à la fin des années 90, de plus en plus leur place sur le marché du travail, réduisant considérablement l'écart qui les sépare des hommes, mais elles tendent aussi, dans une proportion croissante, à ne plus vivre en couple.

Background:Nova Poshta, a leading Ukrainian logistics company, faced with the disruption caused by the 2022full-scaled Russian invasion, strategically adapted by expanding into Europe under the new brand"Nova Post," becoming the first Ukrainian company to enter the EU internal market during wartime.Despite the challenges posed by the war, Nova Post entered 13 European countries, aiming to servethe Ukrainian diaspora while also attracting a broader European customer base.Problem:Despite the fact that the Temporary Protection Directive was crucial in harmonizing the EU’sresponse to the humanitarian crisis caused by the war and allowing Nova Post to target displacedUkrainians as their primary audience, the company faced significant legal challenges and varyingenforcement across member states, particularly affecting parcel delivery services and food products.Understanding the harmonization of EU legislation is essential for Nova Post's expansion strategy.Research methods:This research undertakes a mix of legal and business methods, namely a legal dogmatic method and aqualitative single-case study, describing the Ukrainian firm Nova Post’s expansion to Europeancountries during wartime.Conclusion:Nova Post's internationalization into the European market has been shaped by strategic entry modes,leveraging network relationships, and adapting to local market conditions. While EU legislation hasprovided a robust framework facilitating smoother logistics, trade in services, and a stable businessenvironment, regulatory fragmentation and non-harmonized procedures across member states posesignificant challenges. Overcoming these barriers through greater regulatory harmonization will becrucial for enhancing efficiency and reducing costs in Nova Post’s cross-border operations.