To study the dynamic behavior of rock support elements, a drop weight setup available at CANMET-MMSL was used. In this project, cone bolts were dynamically loaded with a mass of 1016 kg or 1416 kg released from 1.0 m or 1.5 m. The experimental setup is well equipped to monitor the displacements of both ends of the bolt and the applied force. First, a qualitative analysis revealed the two energy absorption mechanisms of the bolt; the steel elongation and the bolt sliding in the resin. Both mechanisms are present during every test, but their proportions vary significantly. Then, a quantitative analysis revealed certain intrinsic properties of the bolt and the influence of the testing parameters on its response. Also, the energy balance of the system proved that the principle of energy conservation is respected through the measurements and calculations. Finally, a two degrees-of-freedom model is proposed to simulate the test. The simulated displacements and force were found to be in good agreement with the corresponding experimental signals. / Afin d'étudier le comportement dynamique d'éléments de renfort, le banc d'essai Pellini de CANMET-MMSL fut utilisé. Durant ce projet, des boulons d'ancrages coniques furent chargés dynamiquement par une masse de 1016 kg ou 1416 kg relâchée d'une hauteur de 1.0 m ou 1.5 m. Le montage est bien équipé pour enregistrer les déplacements des deux extrémités du boulon ainsi que la force de l'impact. Premièrement, une analyse qualitative a révélé les deux mécanismes d'absorption d'énergie du boulon; l'élongation de l'acier et le glissement du boulon dans la résine. Les deux mécanismes sont présents à chaque test, mais leurs proportions varient significativement. Ensuite, une analyse quantitative a révélé certaines propriétés intrinsèques du boulon ainsi que l'influence des paramètres de test sur sa réponse. Aussi, la balance énergétique du système a prouvé que le principe de conservation d'énergie était bien respecté lors des mesures expérimentales et des calculs. Finalement, un modèle à deux degrés-de-liberté a été proposé pour simuler le test. Les déplacements et la force simulés se sont avérés être en excellent accord avec les mesures expérimentales correspondantes.

A general treatment which includes special cases of the five poses planar four-bar synthesis problem is investigated. There are 0, 2, or 4 real solutions to this problem formulated with five simultaneous equations. This method exposes solutions containing RR, PR, or RP dyads. The kinematic mapping is used to represent planar constraint equations in a three-dimensional projective image space because it offers a comprehensive way to solve problems in kinematic synthesis. The motion of a planar rigid body under a RR constraint can be mapped to points on a skew one-sheet hyperboloid with circles as generators which are generated by intersecting the hyperboloid with planes parallel to X3 = 0 in the image space. Similarly, a RP or PR dyad generates points on a unique hyperbolic paraboloid ruled by lines when intersected with planes parallel to X3 = 0. The five-pose four-bar linkage synthesis problem leads to five second-order constraint equations. By solving the constraint equations for RR dyads or four constraint equations for a RP or a PR dyad, four-bar linkage design parameters can be computed. In this thesis, examples which produce two RR dyads, four RR dyads and one RR dyad with one RP dyad will be analyzed. Furthermore, an approximate solution, with kinematic mapping, is given to the planar elliptical trammel synthesis problem.

Over half of the earth's dry surface is inaccessible to wheeled or tracked vehicles. Even relatively structured indoor or urban environments with steps, stairs, or narrow hallways, are challenging for most wheeled or tracked systems. This is one of the primary motivations for the study of mobile robots with legs. / We propose a new type of quadruped robot with maximum mechanical simplicity---the SCOUT class. Most robots built to date possess many actuated degrees of freedom (DOF) (three or four per leg) thus making them too expensive for practical use. SCOUT robots, on the other hand, feature only one actuated degree of freedom per leg. SCOUT dynamics, while still non-trivial, is greatly simplified compared to that of higher degree of freedom robots. In our analysis, we assume instantaneous plastic impacts occur when a leg touches the ground, and consequently, a momentum transfer occurs that causes step changes in the linear and angular velocities. The calculations of these changes are based on the principle of conservation of angular momentum with respect to the impact toe, since it is that point which acts as pivot, or a free pin joint. A set of walking algorithms based on the controlled momentum transfer have been developed, and validated, using numerical simulations. These algorithms have subsequently been implemented on our walking robots, SCOUT I and SCOUT II. / This thesis will show that, with very simple mechanical design and control strategies stable walking is achievable. However, it is important to note that research currently being undertaken in the ARL group will establish that, with only minimal structural changes, SCOUT will have the ability to run and climb stairs.

Mobile robots are taking an important role in society. They are being used in many industries from entertainment to space exploration. McGill University's Ambulatory Robotics Laboratory recently introduced a new class of quadruped robot---the SCOUT series. These robots feature only one actuated degree of freedom per leg. By keeping the degrees of freedom to a minimum, this class of robots is simpler, less expensive and more reliable than most legged robots built to date. The design and development of the second of these robots, SCOUT II, is the topic of this thesis. Unlike its predecessor SCOUT I, SCOUT II has unactuated prismatic knee joints in addition to the revolute joints, which allow compliant walking, stair-climbing and running gaits to be explored. SCOUT II is a self-contained, autonomous mobile robot whose primary purpose is to serve as the testbed for the various gaits that are being developed. This thesis describes the robot's mechanical design, electrical design, sensors and construction. A preliminary stair-climbing algorithm is developed and simulated. An attempt, though partially unsuccessful, is made to implement this algorithm on SCOUT II. The reasons for the discrepancies between the simulations and the actual system are outlined. This will provide useful insight on modelling parameters, actuator limits and robot dynamics for future stair-climbing, walking and running algorithms that are developed for SCOUT II.

The optimal design of power generating microsystems requires accurate knowledge of the thermal properties of their constituent materials at the appropriate length scale. The goal of this thesis was to build an apparatus for measuring the thermal conductivity of thermally-insulating dielectric materials using the so-called 3-omega technique. This technique utilizes a microfabricated metal line deposited on the specimen to act as a resistive heater. When an alternating current (AC) voltage signal is used to excite the heater at a frequency ω, the periodic heating generates oscillations in the electrical resistance of the metal line at a frequency of 2ω. In turn, this leads to a third harmonic (3ω) in the voltage signal, which is used to infer the magnitude of the temperature oscillations. The frequency dependence of these oscillations can be analyzed to obtain the thermal properties of the specimen. The device consisted of a voltage source, a custom-built analog circuit and sample mount, a lock-in amplifier. The sample was placed within a vacuum chamber and evacuated using a made-to-order vacuum system. Personalised LabVIEW and MATLAB programs were created for autonomous data acquisition and analysis. The 3ω technique is simple, quick and accurate; tests using a standard fused quartz specimen (k = 1.38+/-0.04 W/m•K) yielded a measured thermal conductivity of 1.47+/-0.16 W/m•K. Subsequently, the technique was used to measure the thermal conductivity of Lead Zirconate Titanate (PZT-5A4E), which is a piezoelectric ceramic of interest for integration with microfabricated vibration energy harvesters. This material was found to exhibit a low thermal conductivity of 1.38+/-0.10 W/m•K. / Le design optimal de microsystèmes pour la génération d'énergie demande une connaissance précise des propriétés thermiques des matériaux utilisés, à la bonne échelle. Le but de ce projet fut de créer un instrument pour mesurer la conductivité thermique des matériaux fonctionnels pour ces microsystèmes en utilisant la méthode 3-oméga. Cette méthode se sert d'une ligne métallique déposée en surface qui agit comme élément chauffant. Quand le filament métallique est alimenté par un courant alternatif (CA) à une fréquence ω, la puissance dissipée par effet Joule génère une oscillation sinusoïdale dans la résistance électrique à une fréquence 2ω. Cette résistance électrique sinusoïdale à son tour crée une harmonique de rang 3 (3ω) dans la tension électrique de l'élément chauffant. Cette harmonique est utilisée pour déduire l'amplitude des oscillations de température dans le spécimen. La variation de ces oscillations thermiques en fonction de la fréquence d'excitation nous permet d'obtenir la conductivité thermique de l'échantillon. L'instrument consiste d'une source de tension, un « lock-in amplifier », un circuit analogique et une monture à échantillon personnalisés. L'échantillon fut placé dans une chambre à vide et évacué à l'aide d'un système à vide fait sur mesure. Des programmes LabVIEW et MATLAB fut écrits pour réaliser l'acquisition et l'analyse de donnés automatisées. La méthode 3ω est facile à réaliser et donne des résultats précis : des tests avec des échantillons de quartz amorphe (k = 1.38+/-0.04 W/m•K) ont donné une conductivité thermique de 1.47+/-0.16 W/m•K. Le quartz amorphe fut utilisé comme référence pour valider l'instrument. Par la suite, l'appareil fut utilisé pour caractériser une céramique PZT (Titano-Zirconate de Plomb), un matériau piézoélectrique souvent utilisé dans la fabrication de microgénérateurs pour la récupération d'énergie vibratoire. Un

In this thesis, constant volume combustion of dust mixtures of varying particle size was investigated. A reduced gravity environment assisted in the generation of a quiescent, uniform dust suspension of known concentration, by allowing time for the decay of dispersion turbulence in the absence of gravity sedimentation. The difference between the theoretical and experimental maximum explosion pressures was systematically studied. Heat loss mechanisms, conduction and radiation, were evaluated in order to determine their contribution to the experimental pressure deficit. Gaseous explosions were also studied to validate the method of analysis and to provide a basis for comparison. It was found that conduction plays a negligible role in reducing the maximum explosion pressure in both gaseous and dust combustion until the flame is within one flame thickness from the vessel wall, causing flame quenching. The most significant factor in reducing the maximum explosion pressure was found to be flame quenching by the chamber wall in both the dust and gas flames, however radiative heat loss was found to contribute up to 10% of the experimental pressure deficit in the highly luminous aluminum dust flames.

The object of this thesis is to analyze and control a 3 DoF haptic device. The forward kinematics, the Jacobian, and the static force profile, as well as the gravity compensation model are examined. The experimental characterization of the mechanism leads to the determination of the inertia and inherent damping values. / The first controller applied on this device has an inner loop force feedback and an outer loop position feedback. The stiffness range achieved by this controller is calculated theoretically and then confirmed experimentally. The second controller has an inner loop position feedback and an outer loop force feedback. Again the stiffness range for a virtual object for this controller is found both theoretically and then confirmed experimentally. The two controllers are then coupled into a single controller able to achieve a range of stiffness larger than that achieved by each individual controller. The degree of coupling varies, depending on the desired stiffness, to ensure stable control of the device.

The Ambulatory Robotics Laboratory (ARL) has been pursuing an agenda of developing low cost, simple legged robots, with the hopes of increasing the usefulness of legged robots by reducing their price and increasing their reliability. Currently, ARL is developing the Scout class of robots. These are electrically powered quadruped robots with only one actuated degree of freedom per leg. Previous work with these robots developed bounding gaits, in which the front and back legs operate together as pairs. The topic of this research is to design and implement trotting gaits by using a passive knee. A passive knee has no motor, but relies on natural dynamics and the dynamic coupling with the upper leg for knee angle control. A trot is a walking gait in which the diagonal legs operate together as pairs. In this research, a new passive knee is designed and built. It is interfaced with Scout II, the larger of the two Scout robots at ARL. Models of it are developed and simulations are performed to develop and verify walking controllers. Experiments are performed and two types of trotting gaits are successfully achieved.

The effect of free radical pre-sensitization on the transition from deflagration to detonation (DDT) in a combustible gas has been studied experimentally. Sensitization was achieved before spark ignition and DDT by illuminating a quiescent mixture of hydrogen and chlorine with a weak ultraviolet source. The arrival time of the reaction front was monitored by means of discretely located optical sensors along the length of the detonation tube. / While no observable changes are produced during the early stages of the flame acceleration process, it is found that radical seeding promotes the onset of detonation through a reduction in run-up length and time. This is in accord with the generally accepted view that flame acceleration is mostly governed by molecular and turbulent transport. The photochemical initiation of chain reactions ahead of the flame accelerates the induction kinetics of the mixture. Shock induced auto-ignition is therefore facilitated, thereby promoting DDT during the period of onset.

During recent years, application of light metals has greatly increased in various industries. Magnesium, the lightest of structural metals, and its alloys have gained special attention, and, therefore, the interest in modeling the behavior of these alloys has increased. In many studies, the goal has been finding ways to improve the low formability of Mg alloys. In this thesis, the effect of slip system activity on Mg alloy behavior in both the pre- and post-localization zones is examined. An available crystal plasticity model, that takes into account the initial texture of the material and its evolution with deformation, is modified for the case of HCP materials, and, then, implemented into the commercial finite element software ABAQUS. Employing the crystal plasticity finite element (CPFE) method, the link between micro-deformation on the slip systems in Mg alloys and the macro-scale response of these metals is established. The model is verified for the case of Mg single crystals which are highly anisotropic. The minimum required size of the representative volume element (RVE), i.e. the minimum number of grains and the degree of inhomogeneity in each grain required in the CPFE modeling of Mg alloys is determined. Next, the role of different slip systems present in Mg alloys is studied. The effects of strain-rate sensitivity on the micro- and macro-scale behavior of the material and the link between them are also discussed. Using the observed trends for the slip resistances and strain-rate sensitivity factor, new relations are proposed for the change in these values over the range of warm temperatures (75-250°C). The mechanical response of samples cut from hot-rolled / Au cours des dernières années, l'application de métaux légers a augmenté dans diverses industries. Le magnésium, le plus léger des métaux structuraux, et ses alliages ont acquis une attention particulière et, par conséquent, l'intérêt pour la modélisation du comportement de ces métaux a augmenté. Dans des nombreuses études, l'objectif a été de trouver les moyens d'améliorer la formabilité des alliages de Mg. Dans cette thèse, l'effet de l'activité du système de glissage sur le comportement de l'alliage de Mg dans les zones de pré- et post-localisation est examiné. Un modèle de plasticité cristalline disponible, qui prend en compte la texture initiale du matériau et de son évolution avec la déformation, est modifié pour le cas des matériaux à structure hexagonale compacte, et, ensuite, mis en œuvre dans le programme de calculs d'éléments finis, ABAQUS. Employant la méthode des éléments finis à plasticité cristalline (EFPC), le lien entre la microdéformation sur les systèmes de glissages des alliages du Mg et la réponse à l'échelle macroscopique de ces métaux est établie. Le modèle est vérifié pour le cas des monocristaux de Mg qui sont fortement anisotropes. La taille minimale prescrite de l'élément volumique représentatif (EVR), c'est-à-dire le nombre minimal de grains et le degré d'hétérogénéité dans chaque grain requis dans la modélisation EFPC des alliages du Mg, est déterminée. Ensuite, le rôle des différents systèmes de glissage dans les alliages Mg est étudié. Les effets de la sensibilité à la vitesse de déformation sur le comportement du matériau aux échelles micro- et macroscopique et le$