<p>Vibrating screens are industrial machines used to sort aggregates through their high rotational accelerations. Utilized in mining operations, they are able to screen dozens of tonnes of material per hour. To enhance maintenance and troubleshooting, this thesis introduces a vibration based condition monitoring system capable of observing machine operation. Using acceleration data collected from remote parts of the machine, software continuously detects for abnormal operation triggered by fault conditions. Users are to be notified in the event of a fault and be provided with relevant information.</p> <p>Acceleration data is acquired from a set of sensor devices that are mounted to specified points on the vibrating screen. Data is then wirelessly transmitted to a centralized unit for digital signal processing. Existing sensor devices developed for a previous project have been upgraded and integrated into the monitoring system. Alternative communication technologies and the utilized Wi-Fi network are examined and discussed.</p> <p>The condition monitoring system's hardware and software was designed following engineering principles. Development produced a functional prototype system, implementing the monitoring process. The monitoring technique utilizes signal filtering and processing to compute a set of variables that reveal the status of the machine. Decision making strategies are then employed as to determine when a fault has occurred.</p> <p>Testing performed on the developed monitoring system has also been documented. The performance of the prototype system is examined as different fault scenarios are induced and monitored. Results and descriptions of virtual simulations and live industrial experiments are presented. The relationships between machine faults and detected fault signatures are also discussed.</p> / Master of Applied Science (MASc)

<p>Vibrating screens are mechanical machines used to sort granulated materials based on their particle size. Utilized in the mining industry, these machines can sort tonnes of materials per hour. In the past, McMaster University developed sensor devices that measure and transmit vibration data of these machines to a central data acquisition unit for analysis, tuning, and maintenance purposes. In this thesis, I present the development of two new software systems that are used to process, manage, and present the information gained from these measurements. The first system, the offline vibration analysis software, is used to analyze the vibration data in both time and frequency domain, and presents the measured and calculated data in textual and graphical forms. The second system, the online vibration analysis software, is used by vibrating screens manufacturers and their customers to gather and manage vibration data collected from their vibrating screens by utilizing a central storage. The development process of these systems followed an iterative and incremental approach with continuous feedback from stakeholders. It included extensive requirements gathering to define a model, in terms of data representation, that captures the business logic and practices of the industry. Furthermore, it used standard architectures such as Model View Controller (MVC) and advanced technologies such as Object Relationship Mapping (ORM) for data access to increase flexibility and maintainability. Finally, comprehensive unit testing and thorough security risks evaluation were conducted in order to ensure that these systems are secure and bug free.</p> / Master of Applied Science (MASc)

<p><strong><em>Dedicated to the loving memory of my mother and father,</em></strong></p> <p><strong><em>Zohreh Hojati & Mostafa Emami</em></strong></p> / <p>Commercial interests in polymeric foams continue to increase due to their unique physical characters and the new emerging applications for foamed materials. This thesis investigates the foam development process under non-pressurized conditions as applicable to rotational molding to elucidate the underlying mechanisms in the bubble transformation process and provide an accurate basis for predicting the morphological structure and macroscopic properties of the foamed materials. It was found that the foaming mechanism is comprised of four distinct stages: two stages of bubble nucleation, primary and secondary nucleation, followed by bubble growth and bubble coalescence/shrinkage. Following the nucleated bubbles during the foaming process revealed that primary nucleation was the controlling stage in determining the final cellular structure. Growth and coalescence mechanisms were dynamically active and competed during both heating and cooling cycles.</p> <p>The influence of the rheological properties on the rate of nucleation and the bubble growth mechanism were investigated. Morphological analysis was used to determine the rheological processing window in terms of shear viscosity, elastic modulus, melt strength and strain-hardening, intended for the production of foams with greater foam expansion, increased bubble density and reduced bubble size. Visualization experiments and theoretical predictions showed that higher viscosity could impede the number of nuclei generated in the foaming system. A bubble growth model and simulation scheme was also developed to describe the bubble growth phenomena that occurred in non-pressurized foaming systems. It was verified that the viscous bubble growth model was capable of depicting the growth behaviors of bubbles under various processing conditions.</p> / Doctor of Philosophy (PhD)

This dissertation details the development and applications of two innovative types of optical filament-based impulsive Raman spectroscopy: filament-assisted Raman spectroscopy (FAIRS) and spectral-to-temporal amplitude mapping polarization spectroscopy (STAMPS). These techniques provide complimentary vibrational and rotational information on molecular systems of interest. Both are powerful due to their impulsive nature which allows for rapid measurement of entire Raman spectra. However, each type of spectroscopy utilizes the filament in a different manner. The recently reported vibrational technique, referred to as filament-assisted impulsive Raman spectroscopy, employs the pulse shortening and continuum generation of filamentation to impulsively excite a massive vibrational coherence in a molecular system for simultaneous measurement of all the Raman-active modes. In the first half of this dissertation, FAIRS is further developed and applied to a plethora of signature molecules. Radioactive decay signature molecules, including nitrogen oxides, ozone, and ions are detected via FAIR spectroscopy. Concurrent generation and detection of ozone, ionic, and excited-state molecules through filamentation is reported for the first time. Production of these species through the strong field chemistry of filamentation and their subsequent filament-driven excitation is a mark of sensitivity of FAIRS. Spatial studies of combustion species in a natural gas flame are also presented. FAIRS monitors the Raman signal intensities of known reactants and products as a function of vertical flame position. The appearance of combustion products as a function of flame height is also tracked. Spectral fringes overlapping the Raman-active modes are present in all measurements and enable more sensitive detection of low signal intensity species. The results described illustrate the potential of FAIRS for threat sensing applications. The rotational technique, referred to as spectral-to-temporal amplitude mapping polarization spectroscopy, temporally chirps the spectral content of the white-light continuum generated during filamentation to map the transient rotational rivals that are impulsively excited by a short pump pulse. In the second half of this dissertation, the initial development and testing, followed by the applications of STAMPS are described. STAMPS proves successful in mapping the rotational wavepacket rephasing of simple linear molecules, including nitrogen, oxygen, and carbon dioxide, as well as the more complicated asymmetric top molecules, ethylene and methanol. The application of STAMPS to the detection of nitrogen oxides and nitrous oxide, which are considered signatures of multiple threat substances and events, is demonstrated. A pressure study of nitrous oxide reveals dephasing effects as a function of time and pressure. These preliminary results also indicate the potential of STAMPS for hazard sensing applications. / Chemistry

This thesis focuses on data-driven modeling and control of batch and batch-like processes. These processes are highly nonlinear and time-varying which, unlike continuous operations, are characterized by the finite duration of operation and absence of equilibrium conditions. This makes the modeling and control approaches available for continuous processes not readily applicable and requires appropriate adaptations of the available approaches to handle a) batch data structure for modeling and b) a control objective different than that of maintaining a steady-state operation as often encountered in a continuous process. With these considerations, this work adapted the batch subspace identification for modeling and control of a variety of batch and batch-like processes. A particular focus of this work was on the application of the proposed ideas on real engineering systems along with simulated case studies. The applications considered in this work are batch crystallization, a hydrogen plant startup dynamics in a collaboration with Praxair Inc. and a rotational molding process in collaboration with the polymer research group at McMaster University. For the seeded batch crystallization process, subspace identification techniques are adapted to identify a linear time invariant model for the, otherwise, infinite dimensional process. The identified model is then deployed in a linear model predictive control (MPC) strategy to achieve crystal size distribution (CSD) with desired characteristics subject to both manipulated input and product quality constraints. The proposed MPC is shown to achieve superior performance and the ability to respect tighter product quality constraints as well as robustness to uncertainty in comparison to an open loop policy as well as a traditional trajectory tracking policy using classical control. In another contribution, merits of handling data variety in a subspace identification framework was demonstrated on the crystallization process. The proposed approach facilitates the specification of a desired shape of the particle size distribution required at the termination of the batch process. Further, novel model validity constraints are proposed for the subspace identification based control framework. In the collaborative work on hydrogen plant startup, it is recognized as a batch-like process due to its similarity to batch processes. Firstly, in this work a high fidelity model of the Hydrogen unit was developed with relevant startup and shutdown mechanisms. This setup is used to mimic the trends in the key process variables during the startup/shutdown operation. The simulated data is used to identify a state-space model of the process and validated on new simulated startup. Further, the approach was demonstrated on real plant data from one of the Praxair's plants. The predictive capabilities of the model provide ample handle for the plant operator for averting failures and abrupt shutdown of the entire plant. This is expected to have immense economic advantages. Finally, the subspace identification based modeling and control approach was applied to a lab-scale rotational modeling (RM) process. It is a polymer processing technique that is characterized by the placement of a polymer resin inside a mold, subsequent closure of the mold, followed by the simultaneous application of uni-axial (as is the case in the present work) or bi-axial rotation and heat. The resin is deposited on the mold wall where it forms a dense unified layer following which, the mold is cooled while still rotating the mold. Once demolding temperatures are achieved, the finished part is removed from the mold. Its potential as a manufacturing process for polymeric components is limited by a number of concerns including difficulties in process control, in particular, determining efficiently the process operation to yield the desired product consistently, and produce new products. This work has contributed by developing optimal control strategies for the process to achieve user-specified product quality and reject variability across batches. The results obtained demonstrate the merits of the proposed approach. / Thesis / Doctor of Philosophy (PhD)

The development of Magnaquench in 1985 by the Delco-Remy laboratories, increased the research of applications of permanent magnets for use in automobiles. However the application of permanent magnet machines for cranking purposes has not been investigated much. Difficult operating conditions, like, a maximum current density of 35A/mm², and the ability to withstand demagnetizing armature currents up to 250% of the stall current require a new design approach to be developed. Commutation in the permanent magnet machine is obtained by a three phase full wave inverter. The machine - inverter model was simulated by a standard method (SPICE), and an second analytical method we developed. A permanent magnet brushless motor and a drive for cranking purposes is designed and simulated as a part of this thesis. / Master of Science

Analysis of rotating machinery requires the collection and evaluation of large quantities of data. For just one machine, the amount of data may become so overwhelmingly great that a thorough examination of all the data is rendered impractical. <b>IMTS</b> (Intelligent Monitoring And Trending System) is a data acquisition system that has been developed to help resolve this problem. <b>IMTS</b> is a pc based system which can collect data that is relevant to diagnostic considerations, perform an evaluation by filtering the data through special standards and store the results for later review. The system is flexible because the data is evaluated by user defined, multi-level references called standards. <b>IMTS</b> operates in the Microsoft Windows 3.0 operating system, which has the advantage of multitasking two or more programs and thereby allows the data to be collected, evaluated and displayed simultaneously. This means that the user does not experience any temporary periods of system inaccessibility as would be the case in a sequential operating system, such as DOS. This thesis discusses the development of <b>IMTS</b> and explains the capabilities of the current system configuration and gives examples of the monitor screen options and trend plotting capabilities. / Master of Science

Heterogeneous reactions between gas-phase oxidants and particulate-phase organic compounds impact many important atmospheric chemical processes. For example, little is known about the reaction dynamics of gaseous oxidants with organic compounds found in the atmosphere. The first step of the reaction between gaseous ozone and solid pentacene was investigated using Reflection Absorption Infrared Spectroscopy (RAIRS). Ozone was found to add to pentacene non-selectively and form a range of products after heavy ozone exposure. The rate limiting step had an activation energy of 17 kJ/mol, which is consistent with the findings of previous ozone oxidation studies for the cleavage of a carbon-carbon double bond. Unfortunately the products could not be used to distinguish between probable reaction mechanisms. Hydroxyl radicals (•OH) play a major role processing atmospheric hydrocarbons. Due to their short lifetimes, not much is known about the dynamics of the first steps of •OH reactions. To investigate these reactions, a rotational state-selector was constructed to filter a molecular beam of •OH for reaction dynamics investigations with organic surfaces. The rotational state-selector was designed to leverage the linear Stark effect to pass only suitable molecules in a particular rotational state and block the flow of any other atoms, molecules and ions in a molecular beam. The state-selector was validated and used to positively deflect molecular beams of methyl iodide and D₂O via the linear Stark effect. Future studies with the rotational state-selector will investigate the initial steps of •OH reactions with solid organic compounds. / Master of Science

The equations of motion are derived for the de-spinning of a rigid body payload by the use of weights attached to the ends of unwinding cables of finite mass that are released when colinear with a radius of the payload. / Master of Science

The analysis of rotating equipment difficulties is currently accomplished by a specialist in rotating equipment examining the signs and symptoms of the equipment, applying his expert judgement, and determining the cause of the machine's difficulty. This thesis covers the development of an off-line expert system that can be used to emulate the expert's ability to interpret the signs and symptoms of the machine, including suggestions of possible further actions to take for repairing the problem or refining the proof for the proposed cause the difficulty. An editor has also been built which will allow an expert to keep the information used by the system current with the state of the art for rotating machinery diagnostics. This thesis documents the development of the PC-based Turbo Prolog expert shell and external knowledge-base editor. The use of the system editor is illustrated by loading current diagnostic table information into a knowledge base. Then the expert program's operation is illustrated by applying the editor-formed database in a typical session. The expert shell and knowledge base can operate as a stand-alone unit for field application. Resident experts in machinery diagnostics can build and update databases for distribution to users in the company to assure full uniform utilization of the current and most correct knowledge. / Master of Science