Engineering Commons^™

An Investigation Into The Effects Of Ion Tracks On Α-Quartz, Bryant Alan Kanies

Masters Theses

"The passage of a swift heavy ion through a material can cause columnar, amorphous nano-structures known as ion tracks. Swift heavy ions are present in a number of applications ranging from nuclear reactors to nuclear waste storage and onboard spacecraft. The study of ion tracks has been ongoing since the late 1950s and has led to several technological advancements. In fact, ion beams have been used to enhance material properties and aid in the production of electrical components. Ion beams, and their resultant ion tracks, can therefore be seen as a method to purposefully alter material properties such as thermal …

Characterization And Tailoring Of Powder Used In Additive Manufacturing And Plasma Spheroidization, Caitlin S. Kriewall

Masters Theses

"There are many processes that use metal powder as the starting material for the production of parts. With the growth of these manufacturing techniques, more critical part applications are being considered. In order to fully understand the process and create consistent parts, powder properties need to be well understood. Selective laser melting (SLM) is a powder bed-based additive manufacturing process. During processing, heat-affected powders are generated and can deposit within the build area. The current work investigated the characterization of heat-affected 304L stainless steel powder using techniques such as scanning electron microscopy, x-ray diffraction and x-ray photoelectron spectroscopy to detect …

Smart Augmented Reality Instructional System For Mechanical Assembly, Ze-Hao Lai

Masters Theses

"Quality and efficiency are pivotal indicators of a manufacturing company. Many companies are suffering from shortage of experienced workers across the production line to perform complex assembly tasks such as assembly of an aircraft engine. This could lead to a significant financial loss. In order to further reduce time and error in an assembly, a smart system consisting of multi-modal Augmented Reality (AR) instructions with the support of a deep learning network for tool detection is introduced. The multi-modal smart AR is designed to provide on-site information including various visual renderings with a fine-tuned Region-based Convolutional Neural Network, which is …

Analysis And Mitigation Of Parallel-Plate Noise For High-Isolation Applications, Zachary Joel Legenzoff

Masters Theses

"Achieving highs levels of isolation between different functionalities in a PCB can be challenging. One of the major issues is that vertically adjacent planes or area fills in a PCB can form a parallel-plate waveguide with no cutoff frequency and serve as an efficient coupling mechanism between interconnects. Due to the finite size of the conductors, reflections off the edges of these parallel-plate cavities can result in the formation of standing-wave patterns with very high field strengths, resulting in high coupling at certain frequencies. This noise coupling mechanism can be suppressed by connecting the parallel plates together with an adequate …

Imaging The Subsurface In Eastern Part Of Lake Chesterfield Using A Combination Of Geophysical Tools, Jiawei Li

Masters Theses

"The Lake Chesterfield North Dam in Wildwood city, Missouri has been leaking, more or less continuously since the dam was constructed in 1986 despite mitigation efforts in 1988, 1994, 1995, 2004, and 2005. Neither the grouting efforts in 1988, 1994, 1995, 2004 or 2005, nor the placement and rehabilitation of an impervious clay liner in 2005 has solved the problem. Indeed, in June of 2017, the water level in Lake Chesterfield dropped at an alarmingly rapid rate.

Prior to authorizing additional mitigation work, the Lake Chesterfield Home Owners Association (LCHOA) decided to acquire geophysical data across the dry lake bed. …

Microstructural Development And Its Effect On Aqueous Corrosion Of A Borosilicate Glass Ceramic For Waste Vitrification, Nicholas Stephen Roberts

Masters Theses

"Waste loadings of reprocessed spent nuclear fuel vitrified into borosilicate glass can be increased by precipitating environmentally stable phases concentrated with waste components in a chemically stable glass matrix. The principal objective of this thesis was to characterize the development of crystalline powellite (CaMoO₄ and related phases) and oxyapatite (Ca₂LN₈Si₆O₂₆) in borosilicate glass-ceramics and to determine how the formation of those phases affected its chemical durability.

Borosilicate glasses provided by PNNL were re-melted and quenched at rates from over 300⁰C/s to ~0.05⁰C/s. Isothermal heat treatment experiments were conducted by quenching melts …

Modulated Photothermal Radiometry: Detector Sensitivity Study And Experimental Setup, Jessica Nicole Seals

Masters Theses

"This thesis outlines the development of a system used for determining the surface thermal diffusivity of both non-irradiated and irradiated materials. The motivation for this work is to establish a modulated photothermal radiometry (PTR) system on the campus of Missouri University of Science and Technology. One of the main efforts described in this thesis is the design and construction of the physical apparatus. Along the way, it was necessary to perform a detailed sensitivity analysis of the system to determine whether the expected signal emitted from the sample falls within the bounds of detectivity for the HgCdTe (MCT) detector used …

Investigation Of Proppant Static Settling Velocity In Hydraulic Fractures Using Viscoelastic Linear Gel, Vismay Manishbhai Shah

Masters Theses

"Few studies have quantified proppant transport in static conditions using actual proppant and validated previously established correlation. The objective of this study is to investigate the rheological properties of the linear gel, and determine the effect of size, shape and specific gravity of the proppant, fracture walls and rheological properties of the fluid on the proppant settling velocity in static condition and validate the previously established correlation.

Shear viscosity and dynamic frequency sweep tests were performed to investigate the viscous and viscoelastic behaviour of the HPG linear gel with five different concentrations. Proppant settling experiments were conducted with different proppant …

Hydraulic Fracture Design Optimization For Nubian Sandstone Formation In Libya, Housameddin Mohamed Sherif

Masters Theses

There is growing interest in developing unconventional oil and gas reserves in Libya, such as the tight portions of the Nubian sandstone.

Well-X7 is a development well drilled to a TD of 13,005' penetrating the Upper Nubain Sandstone (UNSS) at 12,122'-12,207' and the Lower Nubain Sandstone (LNSS) at 12,524'-12,880' KB. Based on open hole logs, the UNSS has 71 ft of net pay and the LNSS was found to have 295 ft of net pay. Openhole logs also showed low permeabilities of 2.5 and 3 md for the UNSS and LNSS, respectively. The well was initially perforated in both zones …

Practical Dwell Times For Switched System Stability With Smart Grid Application, William Roy St. Pierre

Masters Theses

"Switched systems are encountered throughout many engineering disciplines, but confirming their stability is a challenging task. Even if each subsystem is asymptotically stable, certain switching sequences may exist that drive the overall system states into unacceptable regions. This thesis contains a process that grants stability under switching to switched systems with multiple operating points. The method linearizes a switched system about its distinct operating points, and employs multiple Lyapunov functions to produce modal dwell times that yield stability. This approach prioritizes practicality and is designed to be useful for large systems with many states and subsystems due to its ease …

Development Of A Cfd Model Of The Catalytic Combustion Of A Microtube Multi-Mode Propulsion System, Andrew Paul Taylor

Masters Theses

"This thesis presents the process and results of the development of a computational fluid dynamics (CFD) model in ANSYS Fluent 18.1 on the catalytic decomposition of a novel liquid monopropellant in a microtube in order to gain deeper insights than what is available through the experimental data. The CFD model was created using the Euler- Euler Multiphase model in conjunction with the Heterogeneous Reaction submodel. Such a choice of modeling setting was backed up by theory and benchmark computations on multiphase and compressible flow, shown in Section 3 and Appendix A. It was found that the previously determined one-step reaction …

3d Dubins Curves For Multi-Vehicle Path Planning, Yiheng Wang

Masters Theses

"This thesis proposes a unified algorithm for target assignment and path planning in 3D space for multiple Autonomous Underwater Vehicles (AUVs) to visit multiple targets. The multi-target assignment and path planning problem is modeled as a multiple Traveling Salesmen Problem (mTSP) and is usually solved by two separate algorithms: the multiple task assignment problem is first solved by the Genetic Algorithm (GA) using Euclidean distances between the targets; then the 3D path planning problem is solved for each assignment by selecting Dubins curves or other continuity curves. In contrast, this paper embeds the 3D Dubins curve selection into the target …

Tvs Transient Behavior Modeling Method, And System-Level Effective Esd Design For Usb3.X Interface, Pengyu Wei

Masters Theses

"This research proposal presents a methodology whereby a protection device can be modeled in SPICE compatible platforms with respect to the transient behaviors during Electrostatic Discharge (ESD) events. This methodology uses an exclusively "black-box" approach to characterize the parameters of the protection device, thereby allowing it to be implemented without intimate knowledge of the DUT. Results of this methodology can be used to predict the transient response (conductivity modulation and snapback delay) of the ESD protection devices, and thereby predicts how much current could flow into the device (typically a digital IO pin) under protection. The transient behavior modeling methodology …

Conical Folds -- An Artifact Of Using Simple Geometric Shapes To Describe A Complex Geologic Structure, Avery Joseph Welker

Masters Theses

"Accurate representation of the 3D shapes of natural folds is essential to characterization of the dynamic models for fold formation. Geometrical analysis of folds commonly relies upon analyzing patterns defined by the variation in the orientation of poles to planar surfaces deformed by a shortening event when plotted using graphical calculators (e.g., stereogram, polar tangent diagrams) to interpret the shape of folds. Stereograms for which orientation data define small circles are classified as non-cylindrical regular folds and are interpreted as "conical folds," where the shape of the fold is represented by a cone that terminates at a point. Utilizing similar …

Spatial Resolution Study For Magnetic Near-Field Probe, Xin Yan

Masters Theses

"Spatial resolution is an important factor of near-field probe, which represents the ability to distinguish two close radiation sources. Traditional definition of spatial resolution is the distance between peak point and -6dB point when measuring microstrip line. The definition has disadvantage and limitation. In this topic, spatial resolution for magnetic near-field probe is studied, and three dimensions of spatial resolution are put forward. An optimized measurement setup is presented to reflect spatial resolution of probe properly. Then, an example is given to show how spatial resolution affects field distribution in near-field measurement"--Abstract, page iv.

System Level Power Integrity Transient Analysis Using A Physics-Based Approach, Jun Xu

Masters Theses

"With decreasing supply voltage level and massive demanding current on system chipset, power integrity design becomes more and more critical for system stability. The ultimate goal of well-designed power delivery network (PDN) is to deliver desired voltage level from the source to destination, in other words, to minimize voltage noise delivered to digital devices. The thesis is composed of three parts. The first part focuses on-die level power models including simplified chip power model (CPM) for system level analysis and the worst scenario current profile. The second part of this work introduces the physics-based equivalent circuit model to simplify the …

Coaxial Cable Ring Resonator Based On Pair Sided Coaxial Cable Bragg Grating Coupler For Sensing Appllication, Xiaotong Tang

Masters Theses

“Coaxial cable based devices, such as coaxial cable Bragg grating (CCBG), coiled coaxial cable resonator have been demonstrated for sensing applications to address the challenges faced by fiber optic sensors (e.g., large strain survivability, installation). Inspired by the fiber ring resonator (FRR), coaxial cable based ring resonator (CCRR) is reported in this thesis. The device mainly formed by a homemade coaxial cable Bragg grating (CCBG) pair based side coupler. Comparing to the commercial coupler, CCBG-SC improves the flexibility of the device for sensing applications. The coupling frequency of the CCBG-based coupler can be modified by changing the grating length and …

Distributed Fiber Optic Sensors For Monitoring Spatially Continuous Strain And Quasi-Distributed Refractive Index Using Optical Frequency Domain Reflectometry, Sasi Jothibasu

Masters Theses

"This thesis is comprised of two papers and they describe distributed fiber optic sensing using an optical frequency domain reflectometry (OFDR) instrumentation system.

The first paper presents about distributed fiber optic sensor embedded within the layers of a composite laminates to monitor the continuous profile of strain using the optical frequency domain reflectometry (OFDR) system. The OFDR system was used to analyze the Rayleigh backscattered signal. The shift in the Rayleigh backscattered spectrum (RBS) was observed to be linearly related to the change in strain of the composite material. The continuous strain sensing using OFDR was demonstrated by an INSTRON …

Enhancing Frp-To-Concrete Bond Behavior By Epoxy Ribs, Cheng Jiang, Baolin Wan, John Omboko

Civil and Environmental Engineering Faculty Research and Publications

The bond between external bonding (EB) of fiber reinforced polymer (FRP) composite materials to concrete is the weakest link in the strengthened concrete flexural members. There are three mechanisms to transfer the interfacial shear between FRP and the concrete substrate, i.e., adhesion, interlocking and friction. This paper proposes a new approach by grooving on the concrete surface before applying epoxy to make epoxy ribs to increase interlocking. An experimental program was conducted to verify the effectiveness of the proposed epoxy ribs. Six grooves perpendicular to the fiber direction were cut on the bonding surface of the concrete blocks. The grooves …

Bs News January/February

Building Services Engineering

No abstract provided.

Life Is A Lab: Developing A Communication Research Lab For Undergraduate And Graduate Education, Autumn P. Edwards, Chad Edwards, Patric R. Spence

Journal of Communication Pedagogy

Tips offered center on classroom discourse, curriculum choices, and potential assignments. In this article, we present tips for creating a thriving undergraduate and graduate communication research lab. Based on our experiences developing and co-directing the Communication and Social Robotics Labs (CSRLs), we offer 10 best practices for acquiring resources and recognition, building a strong lab community, and attaining faculty and student goals for scholarship and beyond. Our overarching approach is framed by Dewey’s (1916) pragmatist educational metaphysic, which stresses student- and subject-centered learning, enlarging experiences, and the co-construction of meaning and knowledge. Although our labs are focused on human-machine communication …

Experienced Mental Workload, Perception Of Usability, Their Interaction And Impact On Task Performance, Luca Longo

Articles

No abstract provided.

Investigating The Application Of Deep Convolutional Neural Networks In Semi-Supervised Video Object Segmentation, Jayadeep Sasikumar

Dissertations

This thesis investigates the different approaches to video object segmentation and the current state-of-the-art in the discipline, focusing on the different deep learning techniques used to solve the problem. The primary contribution of the thesis is the investigation of usefulness of Exponential Linear Units as activation functions for deep convolutional neural architectures trained to perform object semi-supervised segmentation in videos. Mask R-CNN was chosen as the base convolutional neural architecture, with the view of extending the image segmentation algorithm to videos. Two models were created, one with Rectified Linear Units and the other with Exponential Linear Units as the respective …

Is It Worth It? Budget-Related Evaluation Metrics For Model Selection, Filip Klubicka, Giancarlo Salton, John D. Kelleher

Conference papers

Projects that set out to create a linguistic resource often do so by using a machine learning model that pre-annotates or filters the content that goes through to a human annotator, before going into the final version of the resource. However, available budgets are often limited, and the amount of data that is available exceeds the amount of annotation that can be done. Thus, in order to optimize the benefit from the invested human work, we argue that the decision on which predictive model one should employ depends not only on generalized evaluation metrics, such as accuracy and F-score, but …

Whispering-Gallery Mode Microsphere Resonators For Applications In Environmental Sensing, Arun Mallik

Doctoral

Humidity, temperature and volatile organic compounds (VOCs), particularly ammonia, are key environmental conditions that have a major impact on human comfort, well-being and productivity, as well as on agriculture, food processing and storage, electronic manufacturing and many other industries. This results in the urgent need for the development of sensing technologies allowing rapid detection and accurate measurement of these environmental parameters. Over the past decades many electrical as well as optical sensors have been proposed and demonstrated for environmental applications. However, challenge always exists for these sensors in terms of sensitivity, selectivity, detection limit, speed of response and robustness, where …

Electro-Mechanical-Thermal Modeling And Stability Of Pulsed Power Loads On A Dc Network, Joshua Allen Dillon

Dissertations, Master's Theses and Master's Reports

Modern military aircraft are developing larger pulsed power loads varying from new weapon technologies to advanced avionics and other electrical equipment. Pulsing power loads emulate a pulse width modulated signal which have non-linear destabilizing effects on the electrical system. Additionally, these devices have thermal properties that can induce electrical stability issues at low and high temperatures and various pulsing load conditions. These non-linear electrical stability issues carry through to the mechanical and thermal systems of the aircraft and can damage components. The MATLAB/Simulink workspace is used to simulate a non-linear model of an aircraft’s electrical-mechanicalthermal (EMT) system. This system includes …

A Model To Predict Concentrations And Uncertainty For Mercury Species In Lakes, Ashley Hendricks

Dissertations, Master's Theses and Master's Reports

To increase understanding of mercury cycling, a seasonal mass balance model was developed to predict mercury concentrations in lakes and fish. Results indicate that seasonality in mercury cycling is significant and is important for a northern latitude lake. Models, when validated, have the potential to be used as an alternative to measurements; models are relatively inexpensive and are not as time intensive. Previously published mercury models have neglected to perform a thorough validation. Model validation allows for regulators to be able to make more informed, confident decisions when using models in water quality management. It is critical to quantify uncertainty; …

Mitigating The Effect Of Misspeculations In Superscalar Processors, Zhaoxiang Jin

Dissertations, Master's Theses and Master's Reports

Modern superscalar processors highly rely on the speculative execution which speculatively executes instructions and then verifies. If the prediction is different from the execution result, a misspeculation recovery is performed. Misspeculation recovery penalties still account for a substantial amount of performance reduction. This work focuses on the techniques to mitigate the effect of recovery penalties and proposes practical mechanisms which are thoroughly implemented and analyzed.

In general, we can divide the misspeculation penalty into four parts: misspeculation detection delay; stale instruction elimination delay; state restoration delay and pipeline fill delay. This dissertation does not consider the detection delay, instead, we …

Meniscus Modeling And Emission Studies Of An Ionic Liquid Ferrofluid Electrospray Source Emitting From A Magneto-Electric Instability, Brandon Jackson

Dissertations, Master's Theses and Master's Reports

This dissertation presents three studies on the electrospray of ionic liquid ferrofluid. Ionic liquid ferrofluids are electrically conductive super-paramagnetic fluids which respond strongly in the presence of electric and magnetic fields. When a small reservoir of ionic liquid ferrofluid is positioned within a magnetic field, magnetic stresses will deform the fluid interface into a peak. The addition of a strong electric field will further stress the fluid interface until a threshold stress is reached at which point the surface tension cannot contain the combined stresses and a spray of fluid or ions results at the apex. This process is termed …

A Bayesian Network Approach To Battery Aging In Electric Vehicle Transportation And Grid Integration, Mehdi Jafari

Dissertations, Master's Theses and Master's Reports

Nowadays, batteries in electric vehicles (EVs) are facing a variety of tasks in their connection to the power grid in addition to the main task, driving. All of these tasks play a very significant role in the battery aging, but they are highly variable due to the change in the driver behavior, grid connection availability and weather conditions. The effect of these external factors in the battery degradation have been studied in literature by mostly deterministic and some stochastic approaches, but limited to specific cases.

In this dissertation, first, a large-scale deterministic approach is implemented to evaluate the effect of …