Approved for public release, distribution is unlimited / This study concentrates on the empirical characterization of a staggered pin-fin array heat exchanger placed in a modular, rectangular wind tunnel. A full analysis of the heat transfer and pressure drop behavior was conducted on various pin-fin shapes, sizes, and configurations. The study was based on airflow over a wide range of Reynolds numbers in the laminar regime. The empirical data gathered can be used to corroborate and develop better numerical models to characterize the performance of such heat exchangers as well as scale down to the micro level for comparison with micro-heat exchangers. / Lieutenant, United States Navy

Bruning considered sets of isospectral Schrodinger operators with smooth real potentials on a compact manifold of dimension three. He showed the set of potentials associated to an isospectral set is compact in the topology of smooth functions by relating the spectrum to the trace of the heat semi-group. Similarly, we can consider the resonances of Schrodinger operators with real valued potentials on Euclidean space of whose support lies inside a ball of fixed radius that generate the same resonances as some fixed Schrodinger operator, an ``isoresonant" set of potentials. This isoresonant set of potentials is also compact in the topology of smooth functions for dimensions one and three. The basis of the result stems from the relation of a regularized wave trace to the resonances via the Poisson formula (also known as the Melrose trace formula). The second link is the small-t asymptotic expansion of the regularized wave trace whose coefficients are integrals of the potential function and its derivatives. For an isoresonant set these coefficients are equal due to the Poisson formula. The equivalence of coefficients allows us to uniformly bound the potential functions and their derivatives with respect to the isoresonant set. Finally, taking a sequence of functions in the isoresonant set we use the uniform bounds to construct a convergent subsequence using the Arzela-Ascoli theorem.

With the rapid development of the modern technology, radio frequency and microwave systems are playing more and more important roles. Since the time the first microwave device was invented, they have been leading not only the military but also our daily life to a new era. In order to make the devices have more practical applications, more and more strict requirements have been imposed. For example, good adaptability, reduced cost and shrank size are highly required. In this thesis, three devices are designed based on this requirement. At first, a symmetric four-port microwave varactor based 90-degree directional coupler with tunable coupling ratios and reconfigurable responses is presented. The proposed coupler is designed based on the modified structure of a crossover, where varactors are loaded. Then, a novel reconfigurable 3-dB directional coupler is presented. Varactors and inductors are loaded to the device to realize the reconfigurable performance. By adjusting the voltage applied to the varactors, the proposed coupler can be reconfigured from a branch-line coupler (90-degree coupler) to a rat-race coupler (180 degree coupler) and vice versa. At last, two types (Type-I and Type-II) of microwave baluns with generalized structures are presented. Different from the conventional transmission-line-based baluns where λ/2 transmission lines or λ/4 coupled lines are used, the proposed baluns are constructed by transmission lines with arbitrary electrical lengths.

This study of classical and modern harmonic analysis extends the classical Wiener's approximation theorem to locally compact abelian groups. The first chapter deals with harmonic analysis on the n-dimensional Euclidean space. Included in this chapter are some properties of functions in L1(Rn) and T1(Rn), the Wiener-Levy theorem, and Wiener's approximation theorem. The second chapter introduces the notion of standard function algebra, cospectrum, and Wiener algebra. An abstract form of Wiener's approximation theorem and its generalization is obtained. The third chapter introduces the dual group of a locally compact abelian group, defines the Fourier transform of functions in L1(G), and establishes several properties of functions in L1(G) and T1(G). Wiener's approximation theorem and its generalization for L1(G) is established.

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal.

Selon l’ITRS, le transistor à nanotube de carbone est une des alternatives prometteuses au transistor MOS Silicium notamment en termes de taille de composant et d’architectures de circuits innovantes. Cependant, à l’heure actuelle, la maturité des procédés de fabrication de ces technologies ne permet pas de contrôler finement les caractéristiques électriques. C’est pourquoi, nous proposons un modèle compact basé sur les principes physiques qui gouvernent le fonctionnement du transistor à nanotube. Cette modélisation permet de lier les activités technologiques à celles de conception de circuit dans le contexte de prototypage virtuel. Pour peu qu’elle inclut des paramètres reflétant la variation des procédés, il est alors possible d’estimer les performances potentielles des circuits intégrés. Le transistor à nanotube de carbone à modulation de hauteur de barrière (C-CNFET), i.e. « MOS-like », est modélisé analytiquement en supposant le transport balistique des porteurs dans le canal. Le formalisme de Landauer est utilisé pour décrire le courant modulé par le potentiel du canal calculé de façon auto-cohérente avec la charge associée selon le potentiel appliqué sur la grille. Le modèle du transistor à nanotube de carbone double grille, DG-CNFET est basé sur celui du C-CNFET. Ce transistor est de type N ou P selon la polarisation de la grille supplémentaire. Ce transistor est modélisé de manière similaire pour les 3 régions : la partie interne modulée par la grille centrale, et les accès source et drain modulés par la grille arrière. La charge, plus complexe à calculer que celle du C-CNFET, est résolue analytiquement en considérant différentes plages de polarisation et d’énergie. Le modèle du DG-CNFET a été mis en œuvre dans le cadre d’architectures de circuits électroniques innovants : une porte logique à 2 entrées comportant 7 transistors CNFET dont 3 DG-CNFET pouvant, selon la polarisation des 3 entrées de configuration, réaliser 8 fonctions logiques différentes. / According to ITRS, the carbon nanotube transistor is one promising alternative to the silicon MOS transistor particularly in terms of device dimensions and novel circuit architectures. However, today, the fabrication processes maturity of these technologies does not allow controlling accurately their electrical characteristics. That’s why we propose a compact model based on physical principles that govern the nanotube transistor operation. That modelling allows linking the technological activities to the circuit design ones in the virtual prototyping context. As it includes parameters that reflect the processes variation, it is possible to estimate the potential performances of integrated circuits. The barrier-height modulated carbon nanotube transistor (C-CNFET), i.e. MOS-like transistor, is analytically modelled assuming ballistic transport of carriers in the channel. The Landauer’s formalism is used to describe the current modulated by the channel potential which is self-consistently calculated with the associated charge according to the gate potential. The model of the double-gate carbon nanotube transistor, DG-CNFET, is based on the C-CNFET one. That transistor is N or P type depending on the additional gate polarisation. That transistor is modelled in a similar way for the 3 regions: the inner part modulated by the central gate, and the source and drain accesses modulated by the back gate. The charge, more complex to calculate than the C-CNFET one, is analytically solved considering different polarisation and energy ranges. Moreover, the DG-CNFET model has been used into novel electronic circuit architectures: a 2 inputs logic gate, composed of 7 CNFET transistors, 3 of which are DG-CNFET, able to realize 8 different logic functions, according to the polarisation of the 3 configuration inputs.

This thesis concerns the implementation of car sharing technology into a semi autonomous future city sportscar. The vehicle is aimed towards the young rebellious generation who will be living an urban, compact lifestyle. The goal was to create a design language and practical supporting features that would appeal to the target group and express sharing technology. The car can change its visual expression depending on the mode or kind of use. The trunk window is a transparent screen displaying information about availability. In order to enter the car, the window scans the user’s iris and recognises if the person is a subscriber of the service. While using the car, the trunk window turns opaque and the front windows turn transparent. Methods used during the design process included research, sketching, package study, clay modelling, CAD modelling, final visualisation and a physical model.

The contemporary urban development pattern in the United States is characterized by land consumptive nature of development, such as a sprawled development pattern. Out of concern that the social and environmental costs of this development pattern outweigh their benefits, cities, counties and states have created a wide range of policy instruments designed to manage urban growth and to protect open spaces from development. The present research deals with such strategies in three study areas namely Portland Metropolitan Area, OR; Montgomery County, MD; and Orange County, FL in order to find out if growth management strategies have been able to reduce sprawl and promote a compact form of development. Based mainly on secondary sources of information, the research evaluates the characteristics, effectiveness, strengths and weaknesses of selected growth management strategies employed in each of these areas and analyses their implications for promoting a compact form of development.

M.A. / CD-ROM products provide access to information by means of different modes of interaction, often on the same database. Although command language is still widely recognized as the interaction mode which retrieves the most relevant references, it is regarded as difficult to use because of its complex structure. More user friendly modes, for example, menu and direct manipulation are viewed as being more accessible to the up-and-coming end-user. The purpose of this study was to determine by means of an empirical study whether the retrieval effectiveness between two modes of interaction on the same database differed significantly. A literature survey pointed out the unique characteristics of existing modes. It was also established that the traditional measures of retrieval effectiveness through relevance and precision could not be applied in this research. A method was devised in which the results of the two modes were compared. The empirical study was done on the command and form fill-in modes of Wilson Business Abstracts. Total results retrieved through each mode were compared, as well as the ease of entering the search by means of appropriate search facilities for each mode. The results of the research revealed that the presence of unique search facilities in a mode results in better retrieval effectiveness. Searches in both modes also require specific ways of input for optimum quality retrieval and thus has implications for intensive training in search methods.

The project is a vision from the author for future autonomous vehicles in 2030, designed for Volvo. Volvo is one of the pioneering automotive companies for autonomous driving, concerning safety as a priority and taking sustainable responsibility for a better living condition.  In the not too distant future, the author sees people’s perception of mobility will gradually change from traditional private ownership to the ability to move freely. What if a mobility service, coming along with the district you chose to live in, satisfies individual usage needs vary with daily commuting to outdoor trips or moving plans? This type of mobility solution will be ubiquitous, changing the nature of the way people choose to live and move. During the design exploration, the tools varied from ideation sketches, rough package test, photoshop rendering, clay sketching, 3D modelling and experimental display graphic illustrations. This project has been strongly inspired by Scandinavian design and Volvo design principle. Also, the author expressed her vision for Volvo and materials thoughts for components and interior functions. The project outcome is 2030 Volvo Compact Concept, an autonomous sharing and subscription service provided by the residential community.