An accurate determination of muscle force is desired in many applications in different fields such as ergonomics, sports medicine, prosthetics, human-robot interaction and medical rehabilitation. Since individual muscle forces cannot be directly measured, force estimation using recorded electromyographic (EMG) signals has been extensively studied. This usually involves interpretation and analysis of the recorded EMG to estimate the underlying neuromuscular activity which is related to the force produced by the muscle. Although invasive needle electrode EMG recordings have provided substantial information about neuromuscular activity at the motor unit (MU) level, there is a risk of discomfort, injury and infection. Thus, non-invasive methods are preferred and surface EMG (SEMG) recording is widely used. However, physiological and non-physiological factors, including phase cancelation, tissue filtering, cross-talk from other muscles and non-optimal electrode placement, affect the accuracy of SEMG-based force estimation. In addition, the relative movement of the muscle bulk and the innervation zone (IZ) with respect to the electrode attached to the skin are two major challenges to overcome in force estimation during dynamic contractions. The objective of this work is to improve the accuracy of SEMG-based force estimation under static conditions, and devise methods that can be applied to force estimation under dynamic conditions. To achieve this objective, a novel calibration technique is proposed, which corrects for variations in the SEMG with changing joint angle. In addition, a modeling technique, namely parallel cascade identification (PCI) that can deal with non-linearities and dynamics in the SEMG-force relationship is applied to the force estimation problem. Finally, a novel integrated sensor that senses both SEMG and surface muscle pressure (SMP) is developed and the two signal modalities are used as input to a force prediction model. The experimental results show significant improvement in force prediction using data calibrated with the proposed calibration method, compared to using non-calibrated data. Joint angle dependency and the sensitivity to the location of the sensor in the SEMG-force relationship is reduced with calibration. The SEMG-force estimation error, averaged over all subjects, is reduced by 44\% for PCI modeling compared to another modeling technique (fast orthogonal search) applied to the same dataset. Significantly improved force estimation results are also achieved for dynamic contractions when joint angle based calibration and PCI are combined. Using SMP in addition to SEMG leads to significantly better force estimation compared to using only SEMG signals. The proposed methods have the potential to be combined and used to obtain better force estimation in more complicated dynamic contractions and for applications such as improved control of remote robotic systems or powered prosthetic limbs. / Thesis (Ph.D, Electrical & Computer Engineering) -- Queen's University, 2013-08-20 20:46:56.897

The gas-liquid reaction between chlorodifluoromethane (R-22) and methanol, in the presence of sodium hydroxide, was investigated in an isothermal, stirred, semi-batch reactor. The objective of the study was to develop a model for the reaction and to identify the kinetic parameters. Reactor temperature was varied from 283 to 303 K, with inlet R-22 partial pressures between 40.5 and 60.8 kPa (absolute). Solutions containing sodium hydroxide concentrations of between 1.5 and 2.5 mol·dm-3 were charged into the reactor prior to each experiment. Preliminary investigations using the R-22-methanol system revealed that stainless steel was an inappropriate choice of material for the reactor as it displayed catalytic tendencies toward trimethyl orthoformate formation. Consequently, the reactor was constructed from glass and was equipped with an internal cooling coil, a single heating jacket and a temperature control unit. Liquid samples that were withdrawn from the reactor were degassed under vacuum to remove residual chlorodifluoromethane, and thereby inhibit further reaction. Spectrophotometry was used to analyze the liquid samples to determine the concentration of chloride ions in solution. The products obtained were difluorodimethyl ether (major product) and trimethyl orthoformate (by-product) as well as sodium chloride and sodium fluoride salts. Difluorodimethyl ether is a potential replacement for ozone depleting CFC refrigerants. A Box-Behnken experimental design was used to investigate the effect of reaction conditions on the product distribution. Variations in the reaction temperature, initial concentration of sodium hydroxide and inlet partial pressure of R-22 were considered. The modeling of the gas-liquid reactions was based on the -dehydrohalogenation mechanism. Since gas solubility in a liquid decreases in the presence of dissolved salts, the "salting-out" effect on mass transfer was included in the reactor model. Sechenov coefficients for sodium chloride and sodium fluoride were combined to give a salt Sechenov coefficient Ksalt . It was known from the literature that the presence of precipitated salts causes inefficient mixing and inhibits mass transfer, particularly in this system due to the relatively low salt solubilities in methanol. This mixing effect was also included in the appropriate mass transfer terms of the reactor model. The experimental data was fitted to a proposed kinetic scheme. Kinetic parameters for each of the proposed reactions, the Sechenov ‘salting out’ coefficients and the mixing parameter were obtained through the use of a non-linear, least-squares optimization algorithm. For the kinetic study, activation energies of 89.12 and 45.83 kJ·mol-1 were obtained for the difluorodimethyl ether and trimethyl orthoformate formation reactions, respectively, with a Sechenov salt coefficient of 0.712 and a mixing parameter of 22.43. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2013.

This thesis describes the design and construction of a novel two-phase spherical electric machine that generates rotating uniform magnetic fields, known as a fluxball machine. Alternative methods for producing uniform magnetic fields with air-cored solenoidal magnets are discussed and evaluated. Analytical and numerical models of these alternatives are described and compared. The design details of material selection, slot geometry, and mechanical connections are described for the fluxball machine. The electrical properties of the machine are predicted and measured. Based on these properties, two modes of operation for the fluxball machine, normal and resonant, are described, and reference tables of important operating parameters are given. The drive and measurement circuitry for the fluxball machine are described. The magnetic properties of the fluxball machine are measured using Hall effect sensors. The calibration of two different Hall effect sensors is performed, providing the ability to measure the magnetic fields accurately to +or- 1%. Measurements of the magnetic field in the uniform field region are taken and compared with predicted values. The attenuation and distortion of the magnetic fields due to diffusion through the inner fluxball winding is measured as a function of operating frequency. Finally, future uses of this machine for various applications are discussed. / Contract number: N62271-97-G-0026 / US Navy (USN) author.

Consumer value is an important determinant of consumers’ post-use behaviour, for example satisfaction, repeat purchase and word of mouth. The existing research mainly looks at the factors associated with the product and service providers to improve consumer value. Few studies on the role of the consumer in shaping consumer value have found consumer knowledge to be an important element in shaping consumer value. Adopting critical realism, this PhD expands this area of knowledge by investigating knowledge miscalibration (i.e., the inaccuracy in subjective knowledge) as a significant antecedent of consumer value. Most of the time, consumers’ perceptions of what they think they know (i.e., subjective knowledge) has been shown to be different from what they actually know (i.e., objective knowledge). Thus, subjective knowledge is usually inaccurate. This inaccuracy in subjective knowledge relative to objective knowledge is called knowledge miscalibration. Although the effect of knowledge miscalibration on consumers’ purchasing decisions has been investigated in the consumer behaviour literature, its role in the use stage of consumption has received much less attention. The aim of this research is to examine the effect of knowledge miscalibration on product or service use, and more specifically on the value consumers derive from actually using products or services (i.e., value-in-use). In this research a critical realism paradigm is pursued, implying that reality exists in the three domains of the empirical, the actual and the real. The research starts with observing regularity in the empirical domain (i.e., consumer value) followed by imagining the causal power in the actual and the real domains (i.e., knowledge miscalibration), shaping the research question. A retroductive strategy is followed, firstly by proposing the effect of knowledge miscalibration on consumer value and secondly by conceptually and empirically testing this relationship. This research conceptualises that knowledge miscalibration influences consumer value dimensions, described as efficiency, excellence, play and aesthetics. It is suggested that underconfidence (i.e., knowledge miscalibration where subjective knowledge is deflated) and overconfidence (i.e., knowledge miscalibration where subjective knowledge is inflated) influence consumer value dimensions differently as they generate different consequences in use. Therefore, a conceptual model is developed that describes the effect of knowledge miscalibration (i.e., overconfidence and underconfidence) on the dimensions of consumer value. The empirical part of the research is designed by conducting a covariance-based study and an experimental investigation in order to gain both internal and external validity. The covariance-based investigation is conducted in the context of amazon.com online shopping. Knowledge miscalibration and consumer value dimensions are measured in this study. This study supports the negative effect of underconfidence on efficiency, excellence, play and aesthetics and the negative effect of overconfidence on play. The experimental investigation is designed in the context of prezi.com, an online dynamic presentation creation website that enables its users to move between slides, words and images during their presentations. In this study, overconfidence and underconfidence are manipulated and their effects on the dimensions of consumer value are examined. The findings of this study show that underconfidence negatively influences efficiency, excellence and aesthetics, while overconfidence negatively impacts excellence, play and aesthetics. Overall, this PhD concludes that knowledge miscalibration negatively influences the dimensions of consumer value, with the exception of overconfidence impacting efficiency. The contradictory results of the covariance-based study observed in the experimental study can be explained through its inability to account for reciprocal relationships (i.e., where consumer value dimensions also impact knowledge miscalibration) and the existence of a third variable affecting both independent and dependent variables. Furthermore, the context of the experimental study (employing a new consumption task) is proposed to be the main reason for the lack of support for the effect of underconfidence on play.

The Mini-RF radar, launched on the Lunar Reconnaissance Orbiter, imaged the lunar surface using hybrid-polarimetric, transmitting one circular polarization and receiving linear H and V polarizations. Earth-based radar operating at the same frequency has acquired data of the same terrains using circular-polarized transmit waves and sampling circular polarizations. For lunar targets where the viewing geometry is nearly the same, the polarimetry derived from Mini-RF and the earth-based data should be very similar. However, we have discovered that there is a considerable difference in circular polarization ratio (CPR) values between the two data sets. We investigate possible causes for this discrepancy, including cross-talk between channels, sampling, and the ellipticity of the Mini-RF transmit wave. We find that none of these can reproduce the observed CPR differences, though a nonlinear block adaptive quantization function used to compress the data will significantly distort some other polarimetry products. A comparison between earth-based data sets acquired using two different sampling modes (sampling received linear polarizations and sampling circular polarizations) suggests that the CPR differences may be partially due to sampling the data in a different receive polarimetry bases.

In the year 2006, the energy performance directive 2002/91/EG was passed by the European Union, according to this directive the Swedish building code was supplemented by a key measure of energy use intensity (EUI). The implemented EUI equals some energy use within a building divided by its floor area and must be calculated in new housing estate and shown when renting or selling housing property. In order to improve the EUI, energy efficiency refurbishments could be implemented. Building energy simulation tools enables a virtual view a building model and can estimate the energy use before implementing any refurbishments. They are a powerful resource when determine the impact of the refurbishment measure. In order to obtain a correct model which corresponds to the actual energy use, some adjustments of the model are often needed. This process refers to as calibration. The used EUI has been criticized and thus, the first objective in this work was to suggest an alternative key measure of a buildings performance. The results showed that the currently used EUI is disfavoring some districts in Sweden. New housing estate in the far north must take more refined actions in order to fulfill the regulation demand, given that the users are behaving identical regardless where the house is located. Further, the suggested measure is less sensitive to the users’ behavior than the presently used EUI. It also has a significance meaning in building design as it relating the building shape and thermal properties and stating that extreme building shapes must undergo a stricter thermal construction rather than buildings that are more compact. Thus, the suggested key measure also creates a communication link between architects and the consultant constructors. The second objective of this thesis has been to investigate a concept of calibration using the data normally provided by energy bills, i.e. some monthly aggregated data. A case study serves to answer this objective, by using the building energy simulation tool IDA ICE 4.7 and a building located in Umeå, Sweden. The findings showed that the used calibration approach yielded a model considered as calibrated in eleven of twelve months. Furthermore, the method gives a closer agreement to the actual heat demand rather than using templates and standardized values. The major explanation of the deviation was influence of the users, but also that the case study building burden with large heat losses by domestic hot water circulation and thus, more buildings should be subjected to this calibration approach.

Braking is mainly controlled by the engine. Friction between a pair of pads and a rotating disc converts the kinetic energy of the vehicle into heat. High temperatures can be reached in the system which can be detrimental for both, components and passenger safety. Numerical techniques help simulate load cases and compute the temperatures field in brake disc and brake pads. The present work implements a Finite Element (FE) toolbox in Matlab/Simulink able to simulate different braking manoeuvres used for brake dimensioning mainly in the early phase of car development process. The brake pad/disc geometry is considered as an axisymmetric body assuming negligible temperature gradient along the circumference of the disc. Calibration using three control factors namely: heat coefficient during braking , acceleration  and emissivity  for the implemented thermal model is performed using experimental investigation at Volvo Car Corporation (VCC) for three specific severe load cases. The thermal model is extended to measure brake fluid temperatures to ensure no vaporisation occurs. Simulation results of the brake disc and brake pad show good correlation with the experimental tests. A sensitivity analysis with the control factors showed convective coefficient during acceleration  the most sensitive, with temperature change of around 16%.

L’athérosclérose est une maladie qui cause, par l’accumulation de plaques lipidiques, le durcissement de la paroi des artères et le rétrécissement de la lumière. Ces lésions sont généralement localisées sur les segments artériels coronariens, carotidiens, aortiques, rénaux, digestifs et périphériques. En ce qui concerne l’atteinte périphérique, celle des membres inférieurs est particulièrement fréquente. En effet, la sévérité de ces lésions artérielles est souvent évaluée par le degré d’une sténose (réduction >50 % du diamètre de la lumière) en angiographie, imagerie par résonnance magnétique (IRM), tomodensitométrie ou échographie. Cependant, pour planifier une intervention chirurgicale, une représentation géométrique artérielle 3D est notamment préférable. Les méthodes d’imagerie par coupe (IRM et tomodensitométrie) sont très performantes pour générer une imagerie tridimensionnelle de bonne qualité mais leurs utilisations sont dispendieuses et invasives pour les patients. L’échographie 3D peut constituer une avenue très prometteuse en imagerie pour la localisation et la quantification des sténoses. Cette modalité d’imagerie offre des avantages distincts tels la commodité, des coûts peu élevés pour un diagnostic non invasif (sans irradiation ni agent de contraste néphrotoxique) et aussi l’option d’analyse en Doppler pour quantifier le flux sanguin. Étant donné que les robots médicaux ont déjà été utilisés avec succès en chirurgie et en orthopédie, notre équipe a conçu un nouveau système robotique d’échographie 3D pour détecter et quantifier les sténoses des membres inférieurs. Avec cette nouvelle technologie, un radiologue fait l’apprentissage manuel au robot d’un balayage échographique du vaisseau concerné. Par la suite, le robot répète à très haute précision la trajectoire apprise, contrôle simultanément le processus d’acquisition d’images échographiques à un pas d’échantillonnage constant et conserve de façon sécuritaire la force appliquée par la sonde sur la peau du patient. Par conséquent, la reconstruction d’une géométrie artérielle 3D des membres inférieurs à partir de ce système pourrait permettre une localisation et une quantification des sténoses à très grande fiabilité. L’objectif de ce projet de recherche consistait donc à valider et optimiser ce système robotisé d’imagerie échographique 3D. La fiabilité d’une géométrie reconstruite en 3D à partir d’un système référentiel robotique dépend beaucoup de la précision du positionnement et de la procédure de calibration. De ce fait, la précision pour le positionnement du bras robotique fut évaluée à travers son espace de travail avec un fantôme spécialement conçu pour simuler la configuration des artères des membres inférieurs (article 1 - chapitre 3). De plus, un fantôme de fils croisés en forme de Z a été conçu pour assurer une calibration précise du système robotique (article 2 - chapitre 4). Ces méthodes optimales ont été utilisées pour valider le système pour l’application clinique et trouver la transformation qui convertit les coordonnées de l’image échographique 2D dans le référentiel cartésien du bras robotisé. À partir de ces résultats, tout objet balayé par le système robotique peut être caractérisé pour une reconstruction 3D adéquate. Des fantômes vasculaires compatibles avec plusieurs modalités d’imagerie ont été utilisés pour simuler différentes représentations artérielles des membres inférieurs (article 2 - chapitre 4, article 3 - chapitre 5). La validation des géométries reconstruites a été effectuée à l`aide d`analyses comparatives. La précision pour localiser et quantifier les sténoses avec ce système robotisé d’imagerie échographique 3D a aussi été déterminée. Ces évaluations ont été réalisées in vivo pour percevoir le potentiel de l’utilisation d’un tel système en clinique (article 3- chapitre 5). / Atherosclerosis is a disease caused by the accumulation of lipid deposits inducing the remodeling and hardening of the vessel wall, which leads to a progressive narrowing of arteries. These lesions are generally located on the coronary, carotid, aortic, renal, digestive and peripheral arteries. With regards to peripheral vessels, lower limb arteries are frequently affected. The severity of arterial lesions are evaluated by the stenosis degree (reduction > 50.0 % of the lumen diameter) using angiography, magnetic resonance angiography (MRA), computed tomography (CT) and ultrasound (US). However, to plan a surgical therapeutic intervention, a 3D arterial geometric representation is notably preferable. Imaging methods such as MRA and CT are very efficient to generate a three-dimensional imaging of good quality even though their use is expensive and invasive for patients. 3D-ultrasound can be perceived as a promising avenue in imaging for the location and the quantification of stenoses. This non invasive, non allergic (i.e, nephrotoxic contrast agent) and non-radioactive imaging modality offers distinct advantages in convenience, low cost and also multiple diagnostic options to quantify blood flow in Doppler. Since medical robots already have been used with success in surgery and orthopedics, our team has conceived a new medical 3D-US robotic imaging system to localize and quantify arterial stenoses in lower limb vessels. With this new technology, a clinician manually teaches the robotic arm the scanning path. Then, the robotic arm repeats with high precision the taught trajectory and controls simultaneously the ultrasound image acquisition process at even sampling and preserves safely the force applied by the US probe. Consequently, the reconstruction of a lower limb arterial geometry in 3D with this system could allow the location and quantification of stenoses with high accuracy. The objective of this research project consisted in validating and optimizing this 3D-ultrasound imaging robotic system. The reliability of a 3D reconstructed geometry obtained with 2D-US images captured with a robotic system depends considerably on the positioning accuracy and the calibration procedure. Thus, the positioning accuracy of the robotic arm was evaluated in the workspace with a lower limb-mimicking phantom design (article 1 - chapter 3). In addition, a Z-phantom was designed to assure a precise calibration of the robotic system. These optimal methods were used to validate the system for the clinical application and to find the transformation which converts image coordinates of a 2D-ultrasound image into the robotic arm referential. From these results, all objects scanned by the robotic system can be adequately reconstructed in 3D. Multimodal imaging vascular phantoms of lower limb arteries were used to evaluate the accuracy of the 3D representations (article 2 - chapter 4, article 3 - chapter 5). The validation of the reconstructed geometry with this system was performed by comparing surface points with the manufacturing vascular phantom file surface points. The accuracy to localize and quantify stenoses with the 3D-ultrasound robotic imaging system was also determined. These same evaluations were analyzed in vivo to perceive the feasibility of the study.

A tracking system that serves as a tool for tracking the movement of surgical instruments has been developed. The system tracks color markers on the surgical instruments. The Continuously Adaptive Mean Shift (CAMSHIFT) methodology was employed for tool tracking and a total distance traversed by the surgical instrument of interest was calculated. Two cameras were used to record the motion of the tool and the software developed was used to track the movement of markers on the tools over subsequent frames. The information thus derived from the two views of cameras was used to calculate the three dimensional coordinates of the location of the marker on the instrument and subsequently the distance traversed. MATLAB, which is a commercial software package, was used to implement the tool tracking algorithm and for developing the GUI (Graphic User Interface). Data was collected using Commercial off the shelf (COTS) camera hardware and processing was done on a 2.2 GHz, 512 MB RAM Intel Pentium 4 computer.

Typescript (photocopy). / Digitized by Kansas State University Libraries