Wood is one of the oldest and most common material used in construction. Since the beginning of the electrification in Canada in late 19th-century, wood poles have been widely used to provide structural support to electric transmission and distribution lines. For example, electrical network in Ontario has over 2 millions distribution poles across the province. Wood poles are typically exposed to severe environmental conditions, which cause deterioration due to wood rotting, insect attack, and weathering. The wood deterioration resulting in loss of strength can compromise the structural integrity of poles. Typical life expectancy of wood varies from 35 to 50 years depending on the environmental condition and type of wood. Electrical distribution infrastructure in Canada is aging. For example, the average age of in-service wood poles in Ontario is estimated to be 29 years with a standard deviation of 15 years. About 300,000 wood poles have been in-service for more than 45 years, which are rapidly reaching to end of expected service life. Different types of non-destructive testing (NDT) methods have been historically used for the condition assessment of wood poles. However, current methods are based on simple concepts that do not consider the variations of wave velocity and wave attenuation in an orthotropic material. The goal of this research investigation is to develop an advanced and reliable NDT technique for in-situ inspection and assessment of wood poles in order to remove unsafe poles from service, extend the service life of sound poles, and support optimum replacement strategies for the renewal of wood pole infrastructure. The thesis presents a new methodology for condition assessment of wood poles using ultrasonic testing based on theoretical, numerical, and experimental studies. The research covers areas such as signal processing, dynamic characterization, statistical reliability analysis, numerical simulations, and laboratory testing. Wood is modeled as a cylindrical orthotropic material with uncertainties in its elastic and mechanical properties. The arrival time of compressional waves as well as full-waveform analysis are used for an integrated evaluation of wood pole. A simplified model of P-wave propagation in pole cross-sections is developed; which allows to (a) estimate the elastic moduli in the radial and tangential directions by solving the inverse problem, and (b) compute the probability density function of P-wave velocity. Both of these parameters are critical for condition assessment; however, they are not available in the literature because of the complexities associated with modelling wood as an orthotropic material. A new specialized software is developed for (a) general signal processing, (b) non-destructive condition assessment of wood poles, and (c) management of a statistical database for the assessment of wood poles. Based on the proposed methodology, a new clamping device is designed and built for the ultrasonic testing of wood poles in the field. The basic background for signal processing covering Fourier analysis, frequency response and impulse response functions, and the complex exponential method for dynamic system identification is reviewed and summarized. The elastic and mechanical properties for most common species of wood used as poles are summarized from the literature, including the main statistical distributions used for their probabilistic characterization. The calibration and basic assumptions for the simulation of wave propagation in orthotropic media using finite element analysis are explained in detail. Numerical modelling is based on finite element method under plain strain condition. The numerical model is calibrated using theoretical results and validated using experimental results from laboratory testing of a new red pine pole. After calibrating the model, numerical simulations were performed to understand ultrasonic wave propagation in cross-sections of sound and decayed wood poles sections. Results of numerical simulations of ultrasonic wave propagation in pole cross-sections are presented. The effect of a void in the cross section on the ultrasonic measurement is discussed. A sample of 8 wood pole cross-sections were subjected to laboratory ultrasonic tests. In the testing, a transmitter was placed at four positions around the pole circumference. For each transmitter position, five receivers were used. The transmitter-receiver system was calibrated to evaluate its transfer function and thus eliminate the inherent characteristics of the transmitter-receiver system from the actual measurements. The experimental results of the condition assessment of new and decayed pole samples are presented in the thesis. The effect of a hole in a new pole was studied and the results were compared with the numerical analysis. A blind test is performed on an aged red pine pole. The predicted areas of decay from the ultrasonic measurements are in good agreement with the actual decay observed from dissecting the pole sections. In summary, the experimental and numerical results presented in this thesis show that the proposed methodology can be successfully applied for condition assessment of in-service wood poles in the electrical network. This method will contribute to cost-effective life cycle management of energy infrastructure as a whole.

The group for non-destructive testing at Uppsala University has recently implemented the phase shift migration method, which is a method to focus images acquired unfocused using ultrasound. However, their work has been limited to 2D data, while for many applications the gathered data is 3D. This project has extended the old implementation to 3D data. The new implementation has been done in two different ways, giving one algorithm that works fast but needs much RAM, and one algorithm that takes long time but works on smaller computers, not demanding as much memory. The fast algorithm works faster than the time it takes to acquire the raw data, which makes real-time use realistic. To test the performance of the two algorithms with respect to image improvement, both against each other and against the previous 2D implementation, a number of experiments were carried out, which showed that, apart from processing time, the two new algorithms were equal in performance. The experiments also showed that the obtained resolution in both x- and y-directions matched the theoretical discussion.

Wood is one of the oldest and most common material used in construction. Since the beginning of the electrification in Canada in late 19th-century, wood poles have been widely used to provide structural support to electric transmission and distribution lines. For example, electrical network in Ontario has over 2 millions distribution poles across the province. Wood poles are typically exposed to severe environmental conditions, which cause deterioration due to wood rotting, insect attack, and weathering. The wood deterioration resulting in loss of strength can compromise the structural integrity of poles. Typical life expectancy of wood varies from 35 to 50 years depending on the environmental condition and type of wood. Electrical distribution infrastructure in Canada is aging. For example, the average age of in-service wood poles in Ontario is estimated to be 29 years with a standard deviation of 15 years. About 300,000 wood poles have been in-service for more than 45 years, which are rapidly reaching to end of expected service life. Different types of non-destructive testing (NDT) methods have been historically used for the condition assessment of wood poles. However, current methods are based on simple concepts that do not consider the variations of wave velocity and wave attenuation in an orthotropic material. The goal of this research investigation is to develop an advanced and reliable NDT technique for in-situ inspection and assessment of wood poles in order to remove unsafe poles from service, extend the service life of sound poles, and support optimum replacement strategies for the renewal of wood pole infrastructure. The thesis presents a new methodology for condition assessment of wood poles using ultrasonic testing based on theoretical, numerical, and experimental studies. The research covers areas such as signal processing, dynamic characterization, statistical reliability analysis, numerical simulations, and laboratory testing. Wood is modeled as a cylindrical orthotropic material with uncertainties in its elastic and mechanical properties. The arrival time of compressional waves as well as full-waveform analysis are used for an integrated evaluation of wood pole. A simplified model of P-wave propagation in pole cross-sections is developed; which allows to (a) estimate the elastic moduli in the radial and tangential directions by solving the inverse problem, and (b) compute the probability density function of P-wave velocity. Both of these parameters are critical for condition assessment; however, they are not available in the literature because of the complexities associated with modelling wood as an orthotropic material. A new specialized software is developed for (a) general signal processing, (b) non-destructive condition assessment of wood poles, and (c) management of a statistical database for the assessment of wood poles. Based on the proposed methodology, a new clamping device is designed and built for the ultrasonic testing of wood poles in the field. The basic background for signal processing covering Fourier analysis, frequency response and impulse response functions, and the complex exponential method for dynamic system identification is reviewed and summarized. The elastic and mechanical properties for most common species of wood used as poles are summarized from the literature, including the main statistical distributions used for their probabilistic characterization. The calibration and basic assumptions for the simulation of wave propagation in orthotropic media using finite element analysis are explained in detail. Numerical modelling is based on finite element method under plain strain condition. The numerical model is calibrated using theoretical results and validated using experimental results from laboratory testing of a new red pine pole. After calibrating the model, numerical simulations were performed to understand ultrasonic wave propagation in cross-sections of sound and decayed wood poles sections. Results of numerical simulations of ultrasonic wave propagation in pole cross-sections are presented. The effect of a void in the cross section on the ultrasonic measurement is discussed. A sample of 8 wood pole cross-sections were subjected to laboratory ultrasonic tests. In the testing, a transmitter was placed at four positions around the pole circumference. For each transmitter position, five receivers were used. The transmitter-receiver system was calibrated to evaluate its transfer function and thus eliminate the inherent characteristics of the transmitter-receiver system from the actual measurements. The experimental results of the condition assessment of new and decayed pole samples are presented in the thesis. The effect of a hole in a new pole was studied and the results were compared with the numerical analysis. A blind test is performed on an aged red pine pole. The predicted areas of decay from the ultrasonic measurements are in good agreement with the actual decay observed from dissecting the pole sections. In summary, the experimental and numerical results presented in this thesis show that the proposed methodology can be successfully applied for condition assessment of in-service wood poles in the electrical network. This method will contribute to cost-effective life cycle management of energy infrastructure as a whole.

Ultrasonic is a transport form of sound. There is no mass transportation, only energy transportation occurs in transfer process. Recently, the ultrasonic was widely used in a variety of purposes. For example¡Gsonar, non-destructive testing, washing and emulsification. Due to the effects of mechanical vibration of ultrasonic on the physiological can promote the percutaneous absorption, ultrasonic is widely used in medical cosmetic field. It can get amazing amount of spending and will continue growth every year. The skin is the body's largest organ, which can be divided into epidermis, dermis and hypodermis. There are two main approaches for drugs to be delivered through the skin: directly penetrate the epidermis and penetrate the lipid layer of cell space. The main purpose of this study is to executing numerical simulation through finite element analysis. By constructing the 3D FEM model of the skin, the effects of different level combinations of the three factors, massage time, amplitudes and frequencies of ultrasonic, on the equivalent strain distributions of the epidermis, dermis, hypodermis and muscle layers were studied, while the skin was massaged by using ultrasonic. The simulation results showed that the difference of maximum equivalent strain is nearly one hundred times between different factor¡¦s level combinations. That means the choice of the appropriate factor¡¦s level combination will affect the efficacy of ultrasonic massage seriously. The numerical simulation results also showed that amplitude is the most influential factor on the equivalent strain for every layers of skin except the epidermis.

Recent advances in microfluidic technologies have enabled integration of the functional units for biological and chemical analysis onto miniaturized chips, called Labon- a-Chip (LOC). However, the effective manipulation and control of colloidal particles suspended in fluids are still challenging tasks due to the lack of clear characterization of particle control mechanisms. The aim of this dissertation is to develop microfluidic techniques and devices for manipulating colloids and biological particles with the utilization of alternating current (AC) electric fields and acoustic waves. The dissertation presents a simple theoretical tool for predicting the motion of colloidal particles in the presence of AC electric field. Dominant electrokinetic forces are explained as a function of the electric field conditions and material properties, and parametric experimental validations of the model are conducted with particles and biological species. Using the theoretical tool as an effective framework for designing electrokinetic systems, a dielectrophoresis (DEP) based microfluidic device for trapping bacterial spores from high conductivity media is developed. With a simple planar electrode having well defined electric field minima that can act as the targetattachment/ detection sites for integration of biosensors, negative DEP trapping of spores on patterned surfaces is successfully demonstrated. A further investigation of DEP colloidal manipulation under the effects of electrothermal flow induced by Joule heating of the applied electric field is conducted. A periodic structure of the electrothermal flow that enhances DEP trapping is numerically simulated and experimentally validated. An acoustic method is investigated for continuous sample concentration in a microscale device. Fast formation of particle streams focused at the pressure nodes is demonstrated by using the long-range forces of the ultrasonic standing waves (USW). High frequency actuation suitable for miniaturization of devices is successfully applied and the device performance and key parameters are explained. Further extension and integration of the technologies presented in this dissertation will enable a chip scale platform for various chemical and biological applications such as drug delivery, chemical analyses, point-of-care clinical diagnosis, biowarfare and biochemical agent detection/screening, and water quality control.

In order to understand the dynamic characteristics of an ultrasonic motor stator, we proposed a modified two- dimensional axisymmetric finite element model to analyze the three-dimensional vibrational problem of piezoelectric annular and circular plates. In this work, displacement fields are properly assumed and the electric effect is included. Following the finite element method, analyses of axisymmetric and nonaxisymmetric vibration of circular and annular plate, and also the stator of ultrasonic motors can be conducted in a convenient way. Natural frequency, location of contact point and elliptic locus of the stator are then calculated. Effects by different geometry design and selected circumferential wave number are discussed. Comparisons of some typical examples are made between the present work and those available in the literature.

Abstract A thin film deposition system using ultrasonic atomization is designed and constructed. Solution containing precursors is transported by carrying gas to the heated substrate where deposition is accomplished by pyrolysis. Tests including series of varying flow rate of carrying gas and varying substrate temperature were carried out with solutions of SnCl4 precursor in C2H5OH solvent and N2 as carrying gas. Also, TaCl5 was used as dopant to improved the electrical conductivity. The effects of doping in crystallinity, surface morphology, optical transmittance and electrical conductivity of the deposited thin films were examined and the optimal percentage of doping for electrical conductivity and optical transmittance was found. XRD reveals that the thin film was amorphous when the deposition temperature was below 350¢J. Polycrystalline thin films with grains size of 30~50nm were obtained with deposition temperature of 400~500¢J and N2 flow rate of 2.5 ~10 l/min. SEM examination reveals that porosity increases with increasing deposition temperature and N2 flow rate, which consequently reduces the electron mobility, as seen in Hall measurement. No discernible difference was observed between the morphology of the doped and undoped thin films. As shown in the UV-Visible spectra representative transmittance of all films at 550nm radiation ranges between 70% and 82%. No discernible effect was observed for Ta-doping. Hall measurement reveals that Ta-doping increases the electron mobility and carrier concentration by several times and one order of magnitude, respectively. The minimum resistivity is 1.2*10-1 £[- cm occurring at 4 at% Ta doping.

An investigation was conducted to determine the feasibility of using the technique of ultrasonic nebulization of water into the anode gas stream for evaporative cooling of a Proton Exchange Membrane (PEM) fuel cell. The basic concept of this form of internal evaporative cooling of the PEM fuel cell is to introduce finely atomized liquid water into the anode gas stream, so that the finely atomized liquid water adsorbs onto the anode and then moves to the cathode via electro-osmotic drag, where this water then evaporates into the relatively dry cathode gas stream, carrying with it the waste thermal energy generated within the fuel cell. The thermal and electrical performance of a 50 cm2 PEM fuel cell utilizing this technique was compared to the performance obtained with conventional water management. Both techniques were compared over a range of humidification chamber temperatures for both the anode and cathode gas streams so as to determine the robustness of the proposed method. The proposed method produced only meager levels of evaporative cooling (at best 2 watts, for which a minimum of 30 watts was required for adequate cooling), but the average cell voltage increased considerably (as much as a 10% gain), and the technique increased the fault tolerance of the fuel cell (the Nafion™ membrane did not dry out even if cell temperature went well in excess of 70° C despite both anode and cathode humidification temperatures of 55° C). An interesting phenomena was also observed wherein the fuel cell voltage oscillated regularly with a period of tens of seconds, and that the amplitude of this oscillation corresponded inversely with the level of humidification received by the fuel cell.

Thesis (M.Ed.)--York University, 2008. Graduate Programme in Education. / Typescript. Includes bibliographical references (leaves 94-103). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:MR38776

Thesis (Ph.D.)--University of Nebraska-Lincoln, 2009. / Title from title screen (site viewed January 5, 2010). PDF text: xiv, 328 p. : ill. (some col.) ; 7.48 Mb. UMI publication number: AAT 3373081. Includes bibliographical references. Also available in microfilm and microfiche formats.