Engineering Commons^™

Uncertainty In Overturning Of Precariously Balanced Rocks Due To Basal Contact, M. Khalid Saifullah, Christine E. Wittich

Department of Civil and Environmental Engineering: Faculty Publications

Precariously balanced rocks (PBRs) are a type of naturally occurring freestanding structure that provides valuable information to constrain seismic hazard at return periods which are important for critical facilities such as nuclear power plants and nuclear repositories. Exposure ages have been established to be in excess of 10,000–30,000 years, which is why precarious rocks are one of the only available means to validate seismic hazard associated with long return periods. One critical component for constraining seismic hazard in this way is the overturning estimate of a given precarious rock as a function of earthquake intensity. However, current state-of-the-art methods for …

A Hierarchical Optimization Approach For Dynamic Pickup And Delivery Problem With Lifo Constraints, Jianhui Du, Zhiqin Zhang, Xu Wang, Hoong Chuin Lau

Research Collection School Of Computing and Information Systems

We consider a dynamic pickup and delivery problem (DPDP) where loading and unloading operations must follow a last in first out (LIFO) sequence. A fleet of vehicles will pick up orders in pickup points and deliver them to destinations. The objective is to minimize the total over-time (that is the amount of time that exceeds the committed delivery time) and total travel distance. Given the dynamics of orders and vehicles, this paper proposes a hierarchical optimization approach based on multiple intuitive yet often-neglected strategies, namely what we term as the urgent strategy, hitchhike strategy and packing-bags strategy. These multiple strategies …

Estimation Of Recursive Route Choice Models With Incomplete Trip Observations, Tien Mai, The Viet Bui, Quoc Phong Nguyen, Tho V. Le

Research Collection School Of Computing and Information Systems

This work concerns the estimation of recursive route choice models in the situation that the trip observations are incomplete, i.e., there are unconnected links (or nodes) in the observations. A direct approach to handle this issue could be intractable because enumerating all paths between unconnected links (or nodes) in a real network is typically not possible. We exploit an expectation–maximization (EM) method that allows dealing with the missing-data issue by alternatively performing two steps of sampling the missing segments in the observations and solving maximum likelihood estimation problems. Moreover, observing that the EM method could be expensive, we propose a …

Imitation Improvement Learning For Large-Scale Capacitated Vehicle Routing Problems, The Viet Bui, Tien Mai

Research Collection School Of Computing and Information Systems

Recent works using deep reinforcement learning (RL) to solve routing problems such as the capacitated vehicle routing problem (CVRP) have focused on improvement learning-based methods, which involve improving a given solution until it becomes near-optimal. Although adequate solutions can be achieved for small problem instances, their efficiency degrades for large-scale ones. In this work, we propose a newimprovement learning-based framework based on imitation learning where classical heuristics serve as experts to encourage the policy model to mimic and produce similar or better solutions. Moreover, to improve scalability, we propose Clockwise Clustering, a novel augmented framework for decomposing large-scale CVRP into …

Analysis Of The Performance, Recertification, And Sustainability Of A Cessna 172n Modified With An O-360-A4m Powerplant, Variable Timing Electronic Ignition, And Tuned Exhaust, Kelsey Lee Kaht

Theses and Dissertations

The purpose of this thesis is to discuss the performance, modification, and recertification of the test aircraft, a Cessna 172N that has been equipped with an O-360-A4M power plant, tuned exhaust, and variable timing electronic ignition, and to compare the aircraft to a stock aircraft and other high-performance aircraft to determine the feasibility of the modifications. 65 knot, 80 knot, and 95 knot steady state climb and 2000 ft and 5000 ft level acceleration tests were performed with the test aircraft at the Melbourne Orlando International Airport. The weather was clear with calm wind, and there was only one issue …

Construction Of A Real-Time Forecast Model With Deep Learning Techniques For Coastal Engineering & Processes: Nested In Basin Scale Suite Of Models, Md Ahsan Habib

Theses and Dissertations

The study aims to develop a robust and adaptable real-time forecasting system for coastal and estuarine regions, considering the challenges of limited or unavailable forecast data. To address the challenge of data unavailability, this study proposes the application of a deep learning model (DLM). This research involves the development of a high-resolution numerical model nested within global models. Calibration and validation are performed by comparing the model with observed data. The study explores the effects of various parameters, such as vertical resolution, wind variability, and bottom roughness, on model performance. It finds that the 10-layer model improves vertical stratification and …

Dechlorination Of Waste Pvc (Polyvinyl Chloride) Using Hydrothermal Liquefaction Method, Vahab Ghalandari

Theses and Dissertations

In 2019, waste plastic production in the United States (U.S.) amounted to approximately 73 million metric tons. Projections indicate that by 2030, the generation of waste plastic in the U.S. will increase to nearly 90 million metric tons, and by 2060, it is expected to surpass 140 million metric tons. One prominent type of waste plastic is polyvinyl chloride (PVC), characterized by its high chlorine content, making it a halogenated plastic. This dissertation presents a comprehensive investigation of the dechlorination of waste PVC (WPVC) through various hydrothermal liquefaction (HTL) methods to produce environmentally friendly solid and liquid products. In this …

Evolution Mechanism Of Grain Orientation And Texture Distribution Of Ti-6.5al-3.5mo-1.5zr-0.3si Alloy Under Electroshocking Treatment, Jian Zhou, Chang Liu, Yaya Wu, Lechun Xie, Fei Yin, Dongsheng Qian, Yanli Song, Liqiang Wang, Lai-Chang Zhang, Lin Hua

Research outputs 2022 to 2026

It is well known that the mechanical properties of Ti-6.5Al-3.5Mo-1.5Zr-0.3Si are closely related to its microstructure and texture. In this work, a novel treatment of electroshocking treatment (EST) was adopted to optimize the microstructure and improve the mechanical properties of this titanium alloy. The grain orientation, texture, and mechanical properties of Ti-6.5Al-3.5Mo-1.5Zr-0.3Si alloy under EST were characterized and analyzed. With the increase of EST time to 0.04 s, the resultant acicular secondary αs shows a tendency of spheroidization and the increase in grain diameter, which leads to a little decrease in hardness and yield strength. The increase in EST time …

Characterization And Estimation Of Musculoskeletal Pain Using Machine Learning, Boluwatife Faremi

Master's Theses

Traditional scales utilized for recording pain are known to be highly subjective and biased due to inaccuracies in recollecting actual pain intensities. As a result, machine learning (ML) models that are trained using these scores as ground truth are reported to have low performance for objective pain classification because of the huge disparity between what was felt in moments of pain and the scores recorded afterward.

In the present study, two devices were designed for gathering real-time, continuous in-session subjective pain scores and the recording of the autonomic nervous system (ANS) altered endodermal (EDA) activity. 24 participants were recruited to …

A Case Study Of The Comparison Between Rubberized And Polymer Modified Asphalt On Heavy Traffic Pavement In Wet And Freeze Environment, Dongzhao Jin, Kwadwo Ampadu Boateng, Dongdong Ge, Tiankai Che, Lei Yin, Wayne Harrall, Zhanping You

Michigan Tech Publications, Part 1

Ground tire rubber (GTR) usage in asphalt pavement with the dry process has gained more prominence in recent times. The objective of this work is to investigate the pavement performance of GTR-modified asphalt pavement and polymer-modified asphalt pavement on heavy volume of traffic conditions in Michigan's wet and freeze environment. A suite of laboratory tests was done to evaluate the pavement performance of GTR-modified and polymer-modified asphalt mixtures. To reveal the strain and stress relationship under different frequencies and temperatures, the dynamic modulus test was applied. The Hamburg wheel tracking device (HWTD) was used to assess the high-temperature deformation resistance. …

Comparison Of Asphalt Emulsion-Based Chip Seal And Hot Rubber Asphalt-Based Chip Seal, Dongzhao Jin, Lei Yin, Kai Xin, Zhanping You

Michigan Tech Publications, Part 1

The use of asphalt emulsion chip seal and hot rubber chip seal as pavement preservation techniques has been gaining popularity. This study aims to compare the laboratory performance of asphalt emulsion and hot rubber asphalt used in chip seal applications. Interlayer shear strength (ISS) and interlayer tensile strength (ITS) tests were designed to evaluate the bond quality of the chip seal samples prepared for both materials. The sweep test was used to estimate the aggregate loss of the chip seal on the asphalt pavement. The universal testing machines were used to evaluate the deterioration of the ISS and ITS values …

Impact Of Microplastics On Organic Fouling Of Hollow Fiber Membranes, Sahar Ghasemi, Bin Yan, Masoumeh Zargar, Nicholas N.A. Ling, Einar O. Fridjonsson, Michael L. Johns

Research outputs 2022 to 2026

Given the potential hazards of microplastics (MPs), it is desirable to efficiently remove them during wastewater treatment processes. To this end, ultrafiltration (UF) membranes can significantly increase the removal of MPs, however the fouling of such membrane modules can also be impacted by the presence of MPs. Magnetic Resonance Imaging (MRI) was used here to non-invasively quantify the effect of polyethylene (PE) MPs accumulation in a 3D UF hollow fiber (HF) membrane module containing 400 fibers, via direct non-invasive velocity imaging of the flow distribution between individual fibers during module operation. The co-effect of MPs and alginate (a common organic …

Liquefaction Proneness Of Stratified Sand-Silt Layers Based On Cyclic Triaxial Tests, Arpit Jain, Satyendra Mittal, Sanjay Kumar Shukla

Research outputs 2022 to 2026

Most studies on liquefaction have addressed homogeneous soil strata using sand or sand with fine content without considering soil stratification. In this study, cyclic triaxial tests were conducted on the stratified sand specimens embedded with the silt layers to investigate the liquefaction failures and void-redistribution at confining stress of 100 kPa under stress-controlled mode. The loosening of underlying sand mass and hindrance to pore-water flow caused localized bulging at the sand-silt interface. It is observed that at a silt thickness of 0.2H (H is the height of the specimen), nearly 187 load cycles were required to attain liquefaction, which was …

In-Situ Thermal And Deformation Characterization Of Additive Manufacturing Processes, Nicholas Phillips

Doctoral Dissertations and Master's Theses

Additive manufacturing (AM) is a rapidly growing industry with numerous applications in the aerospace industry such as aircraft parts and emergency tools on the International Space Station. Defects in additively manufactured structures, however, can waste a lot of time and money. Being able to monitor the manufacturing process for defects is one of the first steps which can be taken to mitigate these losses. This study focuses on the use of thermography in conjunction with deep learning to identify flaws during 3D printing of composite structures made using Onyx, a mixture of chopped carbon fiber and nylon, composite prints. In …

Distributed Deep Learning Optimization Of Heat Equation Inverse Problem Solvers, Zhuowei Wang, Le Yang, Haoran Lin, Genping Zhao, Zixuan Liu, Xiaoyu Song

Electrical and Computer Engineering Faculty Publications and Presentations

The inversion problem of partial differential equation plays a crucial role in cyber-physical systems applications. This paper presents a novel deep learning optimization approach to constructing a solver of heat equation inversion. To improve the computational efficiency in large-scale industrial applications, data and model parallelisms are incorporated on a platform of multiple GPUs. The advanced Ring-AllReduce architecture is harnessed to achieve an acceleration ratio of 3.46. Then a new multi-GPUs distributed optimization method GradReduce is proposed based on Ring-AllReduce architecture. This method optimizes the original data communication mechanism based on mechanical time and frequency by introducing the gradient transmission scheme …

Lift Force Analysis For An Electrodynamic Wheel Maglev Vehicle, Colton W. Bruce, Jonathan Bird, Matthew K. Grubbs

Electrical and Computer Engineering Faculty Publications and Presentations

This paper used an analytic based 3-D second order vector potential model to study the vertical dynamic force ripple and dynamic airgap height change when using a one pole-pair electrodynamic wheel (EDW) maglev vehicle. A one-pole pair EDW creates the lowest lift specific power; however transient finite element analysis (FEA) also shows that the one pole-pair EDW will create a large oscillating vertical force when maintaining a static airgap height. A dynamically coupled eddy current model was used to confirm that when the airgap length is allowed to change with time then an increase in vertical airgap creates a large …

Design Of A Burst Mode Ultra High-Speed Low-Noise Cmos Image Sensor, Xin Yue

Dartmouth College Ph.D Dissertations

Ultra-high-speed (UHS) image sensors are of interest for studying fast scientific phenomena and may also be useful in medicine. Several published studies have recently achieved frame rates of up to millions of frames per second (Mfps) using advanced processes and/or customized processes.

This thesis presents a burst-mode (108 frames) UHS low-noise CMOS image sensor (CIS) based on charge-sweep transfer gates in an unmodified, standard 180 nm front-side-illuminated CIS process. By optimizing the photodiode geometry, the 52.8 μm pitch pixels with 20x20 μm^2 of active area, achieve a charge-transfer time of less than 10 ns. A proof-of-concept CIS was designed and …

Effect Of Nanoparticle Loading And Magnetic Field Application On The Thermodynamic, Optical, And Rheological Behavior Of Thermoresponsive Polymer Solutions, Christopher A. P. Neal, Grace V. Kresge, Michelle C. Quan, Valeria León, Nondumiso O. Chibambo, Michelle A. Calabrese

Mechanical Engineering Faculty Publications

Although processing via external stimuli is a promising technique to tune the structure and properties of polymeric materials, the impact of magnetic fields on phase transitions in thermoresponsive polymer solutions is not well-understood. As nanoparticle (NP) addition is also known to impact these thermodynamic and optical properties, synergistic effects from combining magnetic fields with NP incorporation provide a novel route for tuning material properties. Here, the thermodynamic, optical, and rheological properties of aqueous poly(N-isopropyl acrylamide) (PNIPAM) solutions are examined in the presence of hydrophilic silica NPs and magnetic fields, individually and jointly, via Fourier-transform infrared spectroscopy (FTIR), magneto-turbidimetry, …

A Direct Fiber Approach To Model Sclera Collagen Architecture And Biomechanics, Fengting Ji, Manik Bansal, Bingrui Wang, Yi Hua, Mohammad R. Islam, Felix Matuschke, Markus Axer, Ian A. Sigal

Mechanical Engineering Faculty Publications

Sclera collagen fiber microstructure and mechanical behavior are central to eye physiology and pathology. They are also complex, and are therefore often studied using modeling. Most models of sclera, however, have been built within a conventional continuum framework. In this framework, collagen fibers are incorporated as statistical distributions of fiber characteristics such as the orientation of a family of fibers. The conventional continuum approach, while proven successful for describing the macroscale behavior of the sclera, does not account for the sclera fibers are long, interwoven and interact with one another. Hence, by not considering these potentially crucial characteristics, …

An Effective Heuristic To Reduce Total Flowtime For Randomly-Structured Flowshop Problems, Arun John Abraham

Theses

We propose a heuristic to reduce total flowtime in a six-job, four-machine permutation flowshop scheduling problem. This work contributes to the prolific research efforts reported in the permutation flowshop scheduling problem (PFSP).

The heuristic was applied to 102 randomly structured flowshop scheduling problems, with job processing times generated using an integer uniform distribution in the interval [1,100]. The results of computational experiments were deemed satisfactory after being evaluated by using the ordinal and percentile ranks of the resulting total flowtime for the six jobs.

Development Of Intensity Duration Frequency Curve Of The Lower Rio Grande Valley, Binaya Poudel

Theses and Dissertations

Section 1: This chapter incorporates extensive information about the concept of Intensity-Duration-Frequency (IDF) curves, their historical development and usage, specific focus on the Lower Rio Grande Valley, and the importance of using a comprehensive 32-year data set from 1990-2022 to develop these curves.

Section 2: This chapter provides detailed information about the rigorous comparison of the developed IDF curves with previous ones, where past IDF curves were developed using an empirical formula method. The research presented here employs the Gumbel distribution method, providing a fresh perspective and potentially more accurate predictions of future weather extremes.

Section 3: This chapter outlines …

Optimization Of Ultrawide Bandgap Semiconductor Materials For Heterostructure Field Effect Transistors (Hfets), Mohi Uddin Jewel

Theses and Dissertations

Ultra-wide bandgap (UWBG) gallium oxide (Ga2O3), and aluminum gallium oxide (Al_xGa_1-x)₂O₃ materials with bandgap E_G ≥ 4.8 eV are promising for heterostructure field effect transistors (HFETs) with high breakdown voltage and operating at high temperatures. Despite some initial breakthroughs in good quality β-Ga₂O₃ thin films growth on (001), (100), (010), and (201) β-Ga₂O₃ substrates, and promising results on β- (Al_xGa_1-x)₂O₃/β-Ga₂O₃ HFETs fabricated on (010) β-Ga₂O₃ substrates, heat dissipation in Ga2O3 materials and …

First Principles Doping Analysis Of Perovskite- And Ruddlesden-Popper-Based Solid Oxide Fuel Cells, Nicholas Alexander Szaro

Theses and Dissertations

Solid oxide fuel cells (SOFCs) have shown significant promise as a high efficiency energy conversion technology. SOFCs are solid-state, high temperature (600 – 1000 °C), and electrochemical conversion devices that can operate with a wide variety of fuels such as hydrogen, syngas, and hydrocarbon feedstocks. The state-of-the-art SOFC is manufactured with a lanthanum strontium manganite (LSM) cathode, an yttria-stabilizedzirconia electrolyte (YSZ), and a nickel on yttria-stabilized-zirconia (Ni/YSZ) cermet anode. LSM || YSZ || Ni/YSZ SOFCs operate at or above 800 °C to achieve sufficient oxide mobility. The high temperatures introduce problems such as long device start-up, particle sintering, and material …

Leveraging Programmable Switches To Enhance The Performance Of Networks: Active And Passive Deployments, Elie Kfoury

Theses and Dissertations

The performance of networks today is drastically affected by: 1) switches equipped with large buffers, referred to as “bloated buffers”: due to the lack of programmability and traffic visibility in legacy switches, operators nowadays configure large buffers statically without considering the characteristics or dynamics of flows. Such buffers increase the delays on packets, causing the Quality of Service (QoS) of networked applications (e.g., voice over IP, web browsing) to degrade; 2) switches forwarding packets on a best-effort basis: traffic crossing a switch is heterogeneous in many ways. Mixing such traffic in a single queue without any QoS measures can drastically …

Revisiting The Volumetric Swing Frequency Response Method For The Determination Of Limiting Mass Transfer Mechanisms Of N2 And O2 In Carbon Molecular Sieve 3k172, Adam Marshall Burke

Theses and Dissertations

Adsorption-based separations processes, along with the adsorbents that enable them, have benefited from a greater particular focus in recent years, following a desire to improve process energy efficiencies and cost economics. One such adsorbent, carbon molecular sieves (CMS), have likewise been a greater focus. CMS materials offer several key practical uses, such as the separation of nitrogen and oxygen, and the removal of carbon dioxide from methane process streams. In order to effectively design and implement an industrial scale process using a CMS material, the behavior of these gases on the chosen material must be known, including the limiting mass …

Impact Of Dam Height And Grain Size Distribution On Breaching Of Non-Cohesive Dams Due To Overtopping, Heather O'Donal

Theses and Dissertations

The National Inventory of Dams reports 74,400 earthen dams in the United States in 2021, of these dams approximately 27% are considered at high or significant hazard risk, that is dam failure will cause widespread damage and loss of lives. The most frequent cause of dam failure is breaching caused by overtopping. Accurate predictions of breach evolution are thus crucial to determine flood hydrographs for the safety of communities and properties at risk. Laboratory experiments were conducted on non-cohesive, compacted embankments to understand the role of dam height and sediment grain size on breaching caused by overtopping. Dam heights varied …

Predicting Material Structures And Properties Using Deep Learning And Machine Learning Algorithms, Yuqi Song

Theses and Dissertations

Discovering new materials and understanding their crystal structures and chemical properties are critical tasks in the material sciences. Although computational methodologies such as Density Functional Theory (DFT), provide a convenient means for calculating certain properties of materials or predicting crystal structures when combined with search algorithms, DFT is computationally too demanding for structure prediction and property calculation for most material families, especially for those materials with a large number of atoms. This dissertation aims to address this limitation by developing novel deep learning and machine learning algorithms for effective prediction of material crystal structures and properties. Our data-driven machine learning …

An Ml Based Digital Forensics Software For Triage Analysis Through Face Recognition, Gaurav Gogia, Parag H. Rughani

Journal of Digital Forensics, Security and Law

Since the past few years, the complexity and heterogeneity of digital crimes has increased exponentially, which has made the digital evidence & digital forensics paramount for both criminal investigation and civil litigation cases. Some of the routine digital forensic analysis tasks are cumbersome and can increase the number of pending cases especially when there is a shortage of domain experts. While the work is not very complex, the sheer scale can be taxing. With the current scenarios and future predictions, crimes are only going to become more complex and the precedent of collecting and examining digital evidence is only going …

Digital Health Design For Improving Treatment Decisions, Akanksha Singh

Theses and Dissertations

In the age of artificial intelligence and large datasets, information retrieval by querying large databases is an impossible task for the common user due to the information overload. Recommender Systems (RS) for commercial applications like YouTube, Amazon and Netflix were designed to support users by finding items of interest based on their user profiles and various filtering techniques. Health Recommender Systems (HRS) is a category of RSs that provides immense opportunities for application across several healthcare domains and contexts including treatment decision support. Unlike RS applications that focus on analyzing consumer choices, a key differentiator for HRS applications is the …

Deep Cnn-Based Automated Optical Inspection For Aerospace Components, Shashi Bhushan Jha

Doctoral Dissertations and Master's Theses

ABSTRACT

The defect detection problem is of outmost importance in high-tech industries such as aerospace manufacturing and is widely employed using automated industrial quality control systems. In the aerospace manufacturing industry, composite materials are extensively applied as structural components in civilian and military aircraft. To ensure the quality of the product and high reliability, manual inspection and traditional automatic optical inspection have been employed to identify the defects throughout production and maintenance. These inspection techniques have several limitations such as tedious, time- consuming, inconsistent, subjective, labor intensive, expensive, etc. To make the operation effective and efficient, modern automated optical inspection …