Engineering Science - Theses, Dissertations, and other Required Graduate Degree Essays

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Vapochromic coordination polymer immobilization techniques for ammonia sensors with applications to power transformers

Author: 
Date created: 
2019-04-16
Abstract: 

Ammonia detection is important for many applications in the biomedicine, agriculture, and automotive industries. Sensing of ammonia is also crucial in determining the health of power transformers as the presence of ammonia indicates a breakdown in a transformer’s insulating materials. Current methods of gas analysis for detecting ammonia in such applications are costly, complicated, and time consuming. This thesis is concerned with the use of vapochromic coordination polymers (VCPs), which are in this case fluorescence-based gas sensitive polymers, whose emission spectrum changes upon the binding of target gases, e.g., ammonia. VCP materials have shown great promise in ammonia detection due to their superior fluorescence response and selectivity to ammonia but require immobilization to enable their use as a sensor surface. The work presented in this thesis examines several different immobilization techniques for VCPs to create a new class of ammonia sensors. The first immobilization technique explored involves creating a sheet of post arrays in polydimethylsiloxane (PDMS) to trap and adhere the VCPs to the sensing surface. We show that as the shape of the top of the post arrays is changed (e.g. from simple post to mushroom-shaped caps), the sensitivity of the sensing surface changes. Ammonia detection in the amount of 5 ppm is possible with the most pronounced mushroom shaped posts. The second immobilization method involves dissolved polylactic acid (PLA) mixed with VCPs that are deposited on a PLA substrate, resulting in nanoporous membranes (NPMs) that immobilize the VCP. This technique results in ammonia detection of 5 ppm based on available gas concentrations and reveals that a mix ratio of PLA to VCP of 12% wt. to 88% wt. results in a sensor surface with the highest degree of reversibility. This second immobilization technique also makes a sensor surface that is able to directly detect ammonia dissolved in fluids. Because of the ability of multi-phase gas detection with this immobilization technique we determine that it is the more promising of the two immobilization methods. We explore the application of both immobilization methods in the creation of a sealed micro-fluidic ammonia sensor. Our prototypes use a 3D printed cyclic olefin copolymer (COC) micro-fluidic cell, where COC is employed due to its exceptional optical properties and chemical inertness. These sensor cells detect ammonia both in gas and dissolved in fluids (transformer oil) but are limited in a detection of 1,000 ppm using available gas concentrations for testing.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Bonnie Gray
Department: 
Applied Sciences: School of Engineering Science
Thesis type: 
(Thesis) M.A.Sc.

Advances in slot element and array design

Author: 
Date created: 
2019-03-27
Abstract: 

The slot antenna is one of the simplest types of antennas, being the complement of the most fundamental element, the dipole. Its use, particularly in array configurations, remains an active area of research. The reduced electric current density, relative to the dipole, makes it an extremely efficient element at higher frequencies where the ohmic loss, in even the best conducting metals, becomes important. The slot is naturally suited to cavity or hollow waveguide excitation making an array with an inherent low-loss feed for low-loss elements, and capable of high aperture efficiency. On the practical side, the cavity- or waveguide- slot array can be conveniently realized on a robust all-metal sandwich structure. All these advantages make it one of the best array antenna concepts, and the best for high-frequency applications. Newer generations of wireless communication systems continue to move to higher frequencies for physically smaller antennas, and to electrically larger arrays for adaptive beamforming. At the time of writing, frequencies of particular interest are from 6GHz in present systems to mm-wave (30GHz to 300GHz) in emerging systems. These frequencies typically mean high ohmic losses in the antennas and their feeds. Slot antennas are therefore an obvious candidate design for future systems. This dissertation presents advances in the design of waveguide slot arrays, ranging from a new crossed slot element for dual polarization to new on-chip array concepts. In particular, a new design for a dual-band, dual-polarized, shared-aperture slot array is developed for synthetic aperture radar, but the design also has applications in communications. The triangle waveguide is a simpler structure than the usual rectangular shape, and new slot arrays, requiring new solutions to the triangular waveguide, are also developed. A major motivation is their suitability for on-chip deployment using a MEMs self-assembly technique.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Rodney G. Vaughan
Department: 
Applied Sciences: School of Engineering Science
Thesis type: 
(Thesis) Ph.D.

Adaptive corrosion protection system for smart-grid applications

Date created: 
2018-12-13
Abstract: 

Being one of the popular methods over decades, the utilization of the cathodic protection system is proven to be cost-effective in some cases but demands constant observation and monitoring of the corrosion status. Therefore, adaptive corrosion protection system (ACPS) performs better since It always monitors the corrosion status at user-defined intervals and the ACPS adapts the changes of the target metal structure to provide protection against corrosion. In this project, my role is to understand the theoretical concept and a practical case study of the protection system behaviour including the analysis and improvement of the experimental performances. The project works are evolved around three different sections of the ACPS which are firmware, interface and hardware. The optimum goal is to validate the protection system to be more robust, energy efficient and compatible for any kind of future integration.

Document type: 
Graduating extended essay / Research project
File(s): 
Supervisor(s): 
Bozena Kaminska
Department: 
Applied Sciences: School of Engineering Science
Thesis type: 
(Project) M.Eng.

Constructions of high-performance face recognition pipeline and embedded deep learning framework

Author: 
Date created: 
2018-06-28
Abstract: 

Face recognition has been very popular in many research and commercial studies. Due to the uniqueness of human faces, a robust face recognition system can be an alternative to biometrics such as the fingerprint or eye iris recognition in security systems. Recent development in deep learning contributed to many of the success in solving difficult computer vision tasks, including face recognition. In this thesis, a thorough study is presented to walk through the construction of a robust face recognition pipeline and to evaluate the components in each stage of the pipeline. The pipeline consists of four components, face detection module, face alignment module, metric space face feature extraction module, and feature identification module. Different implementations of each module are presented and compared. The performance of each implementation of the system is evaluated on multiple datasets. The combination of a coarse-to-fine convolutional neural network (CNN) based face detection, geometric-based face alignment and discriminative features learning with additive angular margin method are found to achieve the highest accuracies in all datasets. One drawback of this face recognition pipeline is that it consumes a lot of computational resources, making it hard to be deployed on embedded hardware. It would be beneficial to develop a method that allows advanced deep learning algorithms to be run on resource-limited hardware, such that many of the existing devices can become intelligent with low cost. In this thesis, a novel lapped CNN (LCNN) architecture that is suitable for resource-limited embedded systems is developed. The LCNN uses a divide-and-conquer approach to apply convolution to a high-resolution image on embedded hardware. The LCNN first applies convolution to sub-patches of the image, then merges the resulting outputs to form the actual convolution. The resulting output is identical to that of applying a larger-scale convolution to the entire high-resolution image, except that the convolution operations on the sub-patches can be processed sequentially or parallelly by resource-limited hardware.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Jie Liang
Department: 
Applied Sciences: School of Engineering Science
Thesis type: 
(Thesis) M.A.Sc.

Micro Electro Mechanical Gyroscope Based on Thermal Principles

Author: 
Peer reviewed: 
No, item is not peer reviewed.
Date created: 
2019-10-08
Abstract: 

Four variants of a novel single-axis thermal gyroscope were designed, microfabricated, and characterized in this thesis. Unlike conventional gyroscopes that use a solid seismic mass, the thermal gyroscope utilizes a particulate proof mass. The operating principle of the device is differential temperature detection due to the Coriolis effect on an oscillatory gas stream, in response to rotation. The stream is created by alternate expansion and contraction of the gas particles through activation of two or multiple microheaters in a confined volume. The miniature device structure includes multiple temperature detectors symmetrically arranged with respect to the microheaters. Thermocouples and resistive temperature detectors are exclusively used in the designs. Three versions of the device possess planar structures, whereas the other version forms an out-of-plane structure relying on a compliant platform and a locking mechanism. The fabrication process of the device is based on a variety of bulk or surface micromachining technologies on silicon substrates using polyimide and/or silicon dioxide structural layers. As the designs progress, the microstructures are freely suspended over a cavity etched into the substrate or within the volume above the substrate, with minimal structural support.

A precision rotary stage was constructed to accurately measure the device performance. Two variants of the device showed extremely low sensitivities. However, two other versions exhibited excellent linearity within the tested ±1260 °/s, and they demonstrated sensitivities of 0.947 and 1.287 mV/°/s where 20 mW of power was supplied to the heaters. The bandwidths of the devices were measured to be 20 and 40 Hz. The robustness of the devices was validated by the drop shocks of 2722 to 16 398 g (9.81 m/s^2). Despite the ability of rejecting linear accelerations, the devices showed comparable sensitivities to the linear accelerations. A systematic study of the device acceleration sensitivity, with a variety of low- to high-density gases at high pressures, confirmed that the acceleration signal was induced due to low degrees of rotational symmetry in the device topology. An analytical correction factor was developed capable of 5.8-fold nonlinearity compensation. A novel device configuration was also constructed proving 16 times more effective in rejecting the linear acceleration signal.

 

Document type: 
Thesis
File(s): 
Supervisor(s): 
Carlo Menon
Department: 
Applied Sciences: School of Engineering Science
Thesis type: 
(Thesis) Ph.D.

Decision feedback scheme for spatial modulation

Author: 
Date created: 
2019-01-25
Abstract: 

Spatial Modulation (SM) is a newly developed Multiple Input Multiple Output (MIMO) technique where the antenna/spatial constellation is used as an information carrying unit in addition to the modulation constellation. Traditional SM techniques rely on periodic insertion of the pilot symbols to estimate the channel state information; however, it reduces the effective throughput. A differential SM (DSM) technique was developed to circumvent the need of channel estimation altogether. However, the computational complexity of the DSM increases exponentially with the increase of antennas and becomes impractical even for a moderate antenna array. In this scenario a novel clustering based decision feedback (CB-DFB) scheme is proposed in this thesis which similar to DSM does not require any pilot symbols, and yet has a very low complexity. A generalized CB-DFB scheme is later proposed which further overcomes the constraints of traditional SM techniques and increases the overall throughput.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Paul Ho
Department: 
Applied Sciences: School of Engineering Science
Thesis type: 
(Thesis) M.A.Sc.

FMG based continuous finger movement prediction toward partial hand prosthesis control

Date created: 
2018-12-10
Abstract: 

Partial hand amputation forms more than 90% of all the upper limb amputations. To improve the quality of life for partial hand amputees different prosthesis options, including externally-powered prosthesis, have been investigated. This work is exploring Force Myography (FMG) as a technique for regressing grasping movement accompanied by wrist position variations. This study can lay the groundwork for a future investigation of FMG as a technique for controlling externally-powered prostheses continuously. Ten able-bodied participants performed three hand movements while their wrist was fixed in one of the six predefined positions. Two approaches were examined for estimating grasping: (i) one regression model, trained on data from all wrist positions and hand movements; (ii) a classifier that identified the wrist position followed by a separate regression model for each wrist position. Both approaches presented similar performance while the first approach was more than two times faster. The results indicate the potential of FMG to regress grasping movement, accompanied by wrist position variations.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Carlo Menon
Department: 
Applied Sciences: School of Engineering Science
Thesis type: 
(Thesis) M.A.Sc.

EndoVision: A prototype robotic laparoscope and telementoring system allowing intuitive endoscopic visualization

Author: 
Date created: 
2018-12-14
Abstract: 

This project is for the development of a prototype system for endoscopic visualization for minimally invasive surgeries (MIS). The system will assist a surgeon in adjusting and maintaining the field of view (FOV) of an endoscopic system through head motions alone, relieving the need for hands-on adjustment of a camera scope. A surgeon would wear a head-mounted display (HMD) to visualize the area of interest. A market-ready device would include real-time web communication allowing remote surgeons to provide audio and visual feedback during a surgery. This medical device would reduce the number of medical staff needed for an MIS procedure, as well as providing surgeons with assistance from other medical professionals over the web, increasing the success rate of MIS procedures. Uses for this device include: Providing intuitive control of the surgical FOV, training of surgeons in MIS, and as a platform for real-time communication between surgeons at a distance.

Document type: 
Graduating extended essay / Research project
File(s): 
Supervisor(s): 
Andrew Rawicz
Department: 
Applied Sciences: School of Engineering Science
Thesis type: 
(Project) M.Eng.

Quantitative measurements of biological/chemical concentrations using smartphone cameras

Author: 
Date created: 
2018-11-16
Abstract: 

This thesis presents a smartphone-based imaging system capable of quantifying the concentration of an assortment of biological/chemical assay samples. The main goal of this thesis work is to construct an image database which characterizes the relationship between color information and concentrations of the biological/chemical assay sample. For this aim, a designated optical setup combined with image processing and data analyzing techniques was implemented. A series of experiments conducted on selected assays, including fluorescein, RNA Mango, homogenized milk and yeast have demonstrated that our proposed system estimates the concentration of fluorescent materials and colloidal mixtures comparable to currently used commercial and laboratory instruments. Furthermore, by utilizing the camera and computational power of smartphones, eventual development can be directed toward extremely compact, inexpensive and portable analysis and diagnostic systems which will allow experiments and tests to be conducted in remote or impoverished areas.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Ash Parameswaran
Pablo Nepomnaschy
Department: 
Applied Sciences: School of Engineering Science
Thesis type: 
(Thesis) Ph.D.

Development of MRI template library for nucleus accumbens

Date created: 
2017-11-23
Abstract: 

Segmentation of medical images is one of the most critical steps in many clinical applications. In brain MRI analysis, image segmentation is commonly used for measuring and visualizing the brain’s anatomical structures, for analyzing brain changes. In this project a manual template library of Nucleus Accumbens is created by manually segmenting the MRI images. Nucleus Accumbens is situated in the basal ganglia part of brain and is major component of ventral striatum. A protocol is generated in order to recognize the structure and boundaries of Nucleus Accumbens in the MRI images. The FreeSurfer images are used and manually segmented. The FS-LDDMM algorithm is then used for mapping the segmentations over the rest of the subjects. This template library is a heterogeneous combination of healthy and diseased Nucleus Accumbens structures which were used to train FS+LDDMM and therefore, enable FS+LDDMM to identify Nucleus Accumbens over a diverse range of structural variation which would be present for different neurodegenerative diseases. Cross-validations are done in order to compare the efficiency of the FreeSurfer segmented images and the segmentations performed by FS-LDDMM method. The manual template library generated will be used with a multi- atlas segmentation algorithm like FS-LDDMM to segment large number of images acquired from patients with neurodegenerative disorders so as to get better understanding of the diseases.

Document type: 
Graduating extended essay / Research project
File(s): 
Supervisor(s): 
Mirza Faisal Beg
Department: 
Applied Sciences: School of Engineering Science
Thesis type: 
(Project) M.Eng.