Laser Audio Surveillance Device

The purpose of this project was to create an eavesdropping device that operated by pointing a laser beam at a window and reconstructing the audio of a conversation on the other side of the window. The project sought to improve on a previous year\u27s project which was sensitive to the angle between the laser beam and the window surface normal. This system was implemented using a laser, arrangement of lenses, and circuitry including a digital signal processor

On the transport of alkali ions through polymeric mold compounds and polyelectrolyte membranes.

The aim of this work is the attempt in understanding ion transport properties across structured materials such as polyelectrolyte multilayers (PEMs) and highly filled epoxy resins used as an encapsulant, i.e. mold compounds. The ion transport properties are studied by means of the technique of charge attachment induced transport (CAIT), which was recently developed and time-of-flight secondary ion mass spectrometry (ToF-SIMS). The mold compounds studied in this work are of four types (MCP1, MCP2, MCP3, MCP4) with a composition of 80% - 88% of silica filler and the rest of raw materials such as epoxy resin, hardener and flame retardant. The samples are analyzed by means of the CAIT technique, leading to the evaluation of values of ionic conductivity and activation energy related to the process of transport of potassium ions. The ionic conductivity of the mold compounds is on the order of 10-12/10-13 S/cm, while activation energy values are in a range of 1.3 eV - 2.7 eV. For a better understanding of the potassium diffusion process into the mold compounds, the diffusion of potassium through MCP3 sample is investigated via a combination of CAIT method and an ex-situ ToF-SIMS analysis. The ToF-SIMS analysis reveals a depth diffusion profile of the potassium into the material. A mathematical theory is established in order to evaluate the diffusion coefficients for the transport of potassium. According to the numerical procedure, a good fit between experimental and theoretical data is achieved assuming the presence of two different transport pathways operative inside the material: diffusion along the boundaries of grains, i.e. zones of accumulation of the inorganic component of the mold compound and diffusion through the bulk. Diffusion coefficients of DB = 1.8 x 10-21 cm2s-1 and DBG = 5.4 x 10-20 cm2s-1 are found for bulk and grain boundary diffusion, respectively. The PEM films studied in this work are prepared from the layer-by-layer assembly of ionic p-sulfonato-calix[8]arene (calix8) and cationic poly(allylamine hydrochloride) (PAH) onto functionalized gold substrates. Samples with n = 1, 3, 6, 9, 12, 15, 20, 30 bilayers are analyzed by means of the CAIT technique. The data lend support to the conclusion that conductivity, as well as activation energy measurements for (PAH/calix8)n, cannot be acquired under the conditions of the CAIT method, due to the low resistivity shown from the specific PEMs analyzed. Studies on the transport of Li+, K+ and Rb+ through (PAH/calix8)30 are performed by means of CAIT and ToF-SIMS. For each ion beam (Li+, K+, Rb+) two kind of experiments are performed: (PAH/calix8)30 samples are bombarded with the three different alkali ions varying the time for the bombardment, i.e. 5 seconds in one case and 100 seconds in the other. The evaluation of the concentration profiles gives qualitative information regarding the transport properties, whereas numerical analysis of the lithium and rubidium concentration profiles for 5 seconds long bombardment provides quantitative information on the diffusion process. The numerical calculation reveals that the lithium and rubidium transport across the membrane results in a combination of two diffusion pathways accounting for diffusion of slow ions and fast ions. For the lithium case, a good fit is achieved using diffusion coefficients of Dslow,Li+ = 0.4 x 10-16 cm2/s and Dfast,Li+ = 1.2 x 10-15 cm2/s and assuming that 40% of the incoming ions enter the slow pathway, whereas the rest of the ions is transported via a fast pathway. For the rubidium case, the numerical calculation reveals that the fast diffusion pathway is predominant: only the 0.01% of the rubidium ions enter the slow pathway, whereas the rest is dominated from the faster one, with a Dfast,Rb+ = 7 x 10-15 (± 1.5 x 10-15) cm2/s. The study of ion transport of alkali ions Li+ and Rb+ across calixarenes-based PEMs leads thus to the conclusion that the presence of the calixarenes units may influence the type of transport. Lastly, studies of voltage offset measured on current-voltage curves in a typical CAIT experiment are presented. This study aims to give a better understanding of the process beyond the measured voltage offset. In order to do that, a basic CAIT experiment is performed, where a metal plate is bombarded with an ion beam from a potassium emitter of the composition KAlSi2O6 : Mo (1:9). The registered current–voltage curves show finite offsets in the order of 0.5 eV. In order to investigate the detection process of the specific KAlSi2O6 : Mo (1:9) emitter, values of ionic and electronic work function are evaluated. By means of a theoretical model, the recombination of K+ ions from Leucite KAlSi2O6 : Mo (1:9) onto the metal detector is traced to a combination of the ionic work function of the emitter material, the electronic work function of the emitter material and the recombination energy of the elemental potassium I.E.K

The modelling of natural imperfections and an improved space filling curve halftoning technique.

by Tien-tsin Wong.Thesis (M.Phil.)--Chinese University of Hong Kong, 1994.Includes bibliographical references (leaves 72-79).Chapter 1 --- Introduction --- p.1Chapter 1.1 --- The Modelling of Natural Imperfections --- p.1Chapter 1.2 --- Improved Clustered-dot Space Filling Curve Halftoning Technique --- p.2Chapter 1.3 --- Structure of the Thesis --- p.3Chapter 2 --- The Modelling of Natural Imperfections --- p.4Chapter 2.1 --- Introduction --- p.4Chapter 2.2 --- Related Work --- p.6Chapter 2.2.1 --- Texture Mapping --- p.6Chapter 2.2.2 --- Blinn's Dusty Surfaces --- p.7Chapter 2.2.3 --- Imperfection Rule-based Systems --- p.7Chapter 2.3 --- Natural Surface Imperfections --- p.8Chapter 2.3.1 --- Dust Accumulation --- p.8Chapter 2.3.2 --- Scratching --- p.10Chapter 2.3.3 --- Rusting --- p.10Chapter 2.3.4 --- Mould --- p.11Chapter 2.4 --- New Modelling Framework for Natural Imperfections --- p.13Chapter 2.4.1 --- Calculation of Tendency --- p.13Chapter 2.4.2 --- Generation of Chaotic Pattern --- p.19Chapter 2.5 --- Modelling of Dust Accumulation --- p.21Chapter 2.5.1 --- Predicted Tendency of Dust Accumulation --- p.22Chapter 2.5.2 --- External Factors --- p.24Chapter 2.5.3 --- Generation of Fuzzy Dust Layer --- p.30Chapter 2.5.4 --- Implementation Issues --- p.31Chapter 2.6 --- Modelling of Scratching --- p.31Chapter 2.6.1 --- External Factor --- p.32Chapter 2.6.2 --- Generation of Chaotic Scratch Patterns --- p.35Chapter 2.6.3 --- Implementation Issues --- p.36Chapter 3 --- An Improved Space Filling Curve Halftoning Technique --- p.39Chapter 3.1 --- Introduction --- p.39Chapter 3.2 --- Review on Some Halftoning Techniques --- p.41Chapter 3.2.1 --- Ordered Dither --- p.41Chapter 3.2.2 --- Error Diffusion and Dither with Blue Noise --- p.42Chapter 3.2.3 --- Dot Diffusion --- p.43Chapter 3.2.4 --- Halftoning Along Space Filling Traversal --- p.43Chapter 3.2.5 --- Space Diffusion --- p.46Chapter 3.3 --- Improvements on the Clustered-Dot Space Filling Halftoning Method --- p.47Chapter 3.3.1 --- Selective Precipitation --- p.47Chapter 3.3.2 --- Adaptive Clustering --- p.50Chapter 3.4 --- Comparison With Other Methods --- p.57Chapter 3.4.1 --- Low Resolution Observations --- p.57Chapter 3.4.2 --- High Resolution Printing Results --- p.58Chapter 3.4.3 --- Analytical Comparison --- p.58Chapter 4 --- Conclusion and Future Work --- p.69Chapter 4.1 --- The Modelling of Natural Imperfections --- p.69Chapter 4.2 --- An Improved Space Filling Curve Halftoning Technique --- p.71Bibliography --- p.7

Development of a nanogap fabrication method for applications in nanoelectromechanical systems and nanoelectronics

There is a great need for a well-controlled nanogap fabrication technique compatible with NEMS applications. Theoretically, a displacement sensor based on vacuum tunnel junction or a nanogap can be capable of performing quantum-limited measurements in NEMS applications. Additionally, in the context of nanoelectronics, nanogaps are widely demanded to characterize nanostructures and to incorporate them into nanoscale electronic devices. Here, we have proposed and implemented a fabrication technique based on the controlled shrinkage of a lithographically defined gap between two suspended structures by thermal evaporation. We have consistently produced rigid and stable metallic vacuum tunneling junctions at nanometer or subnanometer sizes. The fabricated nanogaps were characterized by I-V measurements and their gap sizes and potential barrier heights were interrogated using the Simmons' model. Throughout this work, high tensile stress silicon nitride thin films were preferred for the fabrication of suspended structures because they have high resonance frequencies with low dissipation, they are mechanically stable, and they are resilient to stiction problem. However, high-stress nitride structures experience a complex shape deformation once they are suspended. The shape deformation is undesired when the precise positioning of the structures is required as in nanogap fabrication. We developed a new method in which the built in stress gradient is utilized to tune the distance between two suspended structures. The technique was simulated by finite element analysis and experimentally implemented to demonstrate a gap tuning capability beyond the lithographic resolution limits

Development of an ontology supporting failure analysis of surface safety valves used in Oil & Gas applications

Treball desenvolupat dins el marc del programa 'European Project Semester'.The project describes how to apply Root Cause Analysis (RCA) in the form of a Failure Mode Effect and Criticality Analysis (FMECA) on hydraulically actuated Surface Safety Valves (SSVs) of Xmas trees in oil and gas applications, in order to be able to predict the occurrence of failures and implement preventive measures such as Condition and Performance Monitoring (CPM) to improve the life-span of a valve and decrease maintenance downtime. In the oil and gas industry, valves account for 52% of failures in the system. If these failures happen unexpectedly it can cause a lot of problems. Downtime of the oil well quickly becomes an expensive problem, unscheduled maintenance takes a lot of extra time and the lead-time for replacement parts can be up to 6 months. This is why being able to predict these failures beforehand is something that can bring a lot of benefits to a company. To determine the best course of action to take in order to be able to predict failures, a FMECA report is created. This is an analysis where all possible failures of all components are catalogued and given a Risk Priority Number (RPN), which has three variables: severity, detectability and occurrence. Each of these is given a rating between 0 and 10 and then the variables are multiplied with each other, resulting in the RPN. The components with an RPN above an acceptable risk level are then further investigated to see how to be able to detect them beforehand and how to mitigate the risk that they pose. Applying FMECA to the SSV mean breaking the system down into its components and determining the function, dependency and possible failures. To this end, the SSV is broken up into three sub-systems: the valve, the actuator and the hydraulic system. The hydraulic system is the sub-system of the SSV responsible for containing, transporting and pressurizing of the hydraulic fluid and in turn, the actuator. It also contains all the safety features, such as pressure pilots, and a trip system in case a problem is detected in the oil line. The actuator is, as the name implies, the sub-system which opens and closes the valve. It is made up of a number of parts such as a cylinder, a piston and a spring. These parts are interconnected in a number of ways to allow the actuator to successfully perform its function. The valve is the actual part of the system which interacts with the oil line by opening and closing. Like the actuator, this sub-system is broken down into a number of parts which work together to perform its function. After breaking down and defining each subsystem on a functional level, a model was created using a functional block diagram. Each component also allows for the defining of dependencies and interactions between the different components and a failure diagram for each component. This model integrates the three sub-systems back into one, creating a complete picture of the entire system which can then be used to determine the effects of different failures in components to the rest of the system. With this model completed we created a comprehensive FMECA report and test the different possible CPM solutions to mitigate the largest risks

Atomic-scale friction : a scanning probe study on crystalline surfaces

Friction is one of the most fascinating and yet elusive phenomena in physics. Everyday life cannot be imagined in the absence of friction. It allows us to walk, to climb stairs, to sit in a chair, to stop a car, to handle tools. In technological applications friction is the evil of all motion and huge amounts of money are spent annually on energetic and mechanical losses due to friction and wear. Friction is also responsible for natural disasters like earthquakes, landslides and avalanches. Along the centuries mankind has tried to understand and control friction but in spite of the huge volume of experimental knowledge with remarkable technical applications, very little is known about the fundamental, elementary processes taking place on the atomic level at the interface between sliding surfaces. The contact between two apparently flat solids consists in reality of a very large number of micro-protrusions or asperities belonging to both contacting surfaces. Studying and understanding the processes responsible for the occurrence of friction at the buried interface of a single-asperity became the tasks of a new but rapidly expanding science called nanotribology. In the present work we have used a variable-temperature ultra-high vacuum atomic force microscope (VT-UHV-AFM) to investigate the frictional properties, namely the stick-slip behavior, of (100) and (111) crystalline diamond and (001) sodium chloride surfaces. While diamond is a technologically important material and a perfect candidate for an ideal friction experiment, NaCl is well established as a representative model, standard surface for nanotribological investigations. In order to properly simulate the interface with a single asperity at the nanoscale, sharp AFM-tips are used on atomically flat surfaces. The ultra-high vacuum conditions are an essential ingredient for well-defined and reproducible experiments. A hard, stable and sharp AFM-tip termination is of the essence for friction measurements. Therefore, using a hot-filament assisted chemical vapor deposition (HF-CVD) of diamond, a method of growing individual good quality diamond crystallites at the apexes of standard Si AFM tips was demonstrated; the resulting tips showed sharpness, hardness, stability and reliable behavior during friction measurements. We have investigated the atomic-scale friction behaviour between standard silicon nitride tips and diamond-coated tips and a specially prepared hydrogen-terminated (100) diamond sample by means of ultra-high vacuum atomic force microscopy. Tunneling experiments revealed a very flat surface and the typical atomic features (dimers) of a (2x1) surface reconstruction of the hydrogen-terminated (100) diamond sample. When using a diamond-terminated tip, for the first time atomically resolved topography, normal force error signal and lateral force maps are simultaneously obtained and perpendicular domains, hydrogen atomic positions and atomic steps between domains could be observed. This was attributed to a very sharp tip, namely one hydrogen atom-terminated tip, describing a stick-slip movement in two orthogonal directions and causing a dynamic rearrangement of the surface atoms; these results were consistent with an ab-initio electronic structure calculation which reveals the fact that the repulsive interaction between the apex H-atom at the tip and H-atoms at the surface is the essential factor that governs the atomic stick-slip behaviour Similar experiments were carried out in UHV on a (111) crystalline diamond surface with standard silicon nitride and diamond-coated tips. The friction measurements with the same diamond-coated tip on this surface led to atomic resolution: the measured periodicity is consistent with the one of the individual hydrogen atoms of the diamond surface. This reconfirmed the use of an atomically sharp tip and, similar to the results on the (100) diamond surface, we believe that the repulsion between the last H-atom of the tip and the H-atoms of the surface termination is the most important ingredient controlling the complicated two-dimensional atomic scale stick-slip behavior observed experimentally. Finally, atomic-scale friction between a silicon tip and the atomically flat (001) NaCl surface was investigated in ultra-high vacuum at various sample temperatures in the interval from 25 to 300 K. The temperature dependence of measured average friction forces is found to be in good qualitative agreement with theoretical models that consider a thermally-activated discontinuous tip movement during scanning and predict higher friction forces at low temperature. Higher mean friction values observed for two temperature values were attributed to possible changes in the tip apex configuration

Nanoscale surface structure–activity in electrochemistry and electrocatalysis

Nanostructured electrochemical interfaces (electrodes) are found in diverse applications ranging from electrocatalysis and energy storage to biomedical and environmental sensing. These functional materials, which possess compositional and structural heterogeneity over a wide range of length scales, are usually characterized by classical macroscopic or “bulk” electrochemical techniques that are not well-suited to analyzing the nonuniform fluxes that govern the electrochemical response at complex interfaces. In this Perspective, we highlight new directions to studying fundamental electrochemical and electrocatalytic phenomena, whereby nanoscale-resolved information on activity is related to electrode structure and properties colocated and at a commensurate scale by using complementary high-resolution microscopy techniques. This correlative electrochemical multimicroscopy strategy aims to unambiguously resolve structure and activity by identifying and characterizing the structural features that constitute an active surface, ultimately facilitating the rational design of functional electromaterials. The discussion encompasses high-resolution correlative structure–activity investigations at well-defined surfaces such as metal single crystals and layered materials, extended structurally/compositionally heterogeneous surfaces such as polycrystalline metals, and ensemble-type electrodes exemplified by nanoparticles on an electrode support surface. This Perspective provides a roadmap for next-generation studies in electrochemistry and electrocatalysis, advocating that complex electrode surfaces and interfaces be broken down and studied as a set of simpler “single entities” (e.g., steps, terraces, defects, crystal facets, grain boundaries, single particles), from which the resulting nanoscale understanding of reactivity can be used to create rational models, underpinned by theory and surface physics, that are self-consistent across broader length scales and time scales

Efficient Semantic Segmentation on Edge Devices

Semantic segmentation works on the computer vision algorithm for assigning each pixel of an image into a class. The task of semantic segmentation should be performed with both accuracy and efficiency. Most of the existing deep FCNs yield to heavy computations and these networks are very power hungry, unsuitable for real-time applications on portable devices. This project analyzes current semantic segmentation models to explore the feasibility of applying these models for emergency response during catastrophic events. We compare the performance of real-time semantic segmentation models with non-real-time counterparts constrained by aerial images under oppositional settings. Furthermore, we train several models on the Flood-Net dataset, containing UAV images captured after Hurricane Harvey, and benchmark their execution on special classes such as flooded buildings vs. non-flooded buildings or flooded roads vs. non-flooded roads. In this project, we developed a real-time UNet based model and deployed that network on Jetson AGX Xavier module

Materials Science and Technology

Materials are important to mankind because of the benefits that can be derived from the manipulation of their properties, for example electrical conductivity, dielectric constant, magnetization, optical transmittance, strength and toughness. Materials science is a broad field and can be considered to be an interdisciplinary area. Included within it are the studies of the structure and properties of any material, the creation of new types of materials, and the manipulation of a material's properties to suit the needs of a specific application. The contributors of the chapters in this book have various areas of expertise. therefore this book is interdisciplinary and is written for readers with backgrounds in physical science. The book consists of fourteen chapters that have been divided into four sections. Section one includes five chapters on advanced materials and processing. Section two includes two chapters on bio-materials which deal with the preparation and modification of new types of bio-materials. Section three consists of three chapters on nanomaterials, specifically the study of carbon nanotubes, nano-machining, and nanoparticles. Section four includes four chapters on optical materials

2015 Conference Abstracts: Annual Undergraduate Research Conference at the Interface of Biology and Mathematics

Schedule and abstract book for the Seventh Annual Undergraduate Research Conference at the Interface of Biology and Mathematics Date: November 21-22, 2015Plenary speaker: Robert Smith, University of OttawaFeatured speaker: Rachel Lenhart, University of Wisconsin, Madiso