Engineering Commons^™

Experimental Study And Piezoresistive Mechanism Of Electrostatic Self-Assembly Of Carbon Nanotubes–Carbon Black/Epoxy Nanocomposites For Structural Health Monitoring, Yanlei Wang, Yao Fu, Ziping Meng, Baolin Wan, Baoguo Han

Civil and Environmental Engineering Faculty Research and Publications

Since electrostatic self-assembly carbon nanotubes–carbon black (CNTs–CB) composite fillers have good electrical conductivity and an easy dispersion process, they were incorporated into epoxy matrix to fabricate the CNTs–CB/epoxy nanocomposites. The mechanical properties, electrical conductivity, piezoresistivity, as well as microstructure characterization of the CNTs–CB/epoxy nanocomposites were experimentally investigated. The piezoresistive mechanisms of the CNTs–CB/epoxy nanocomposites were also established based on tunneling conduction and contacting conduction. The significant improvements in compressive yielding strength and elastic modulus of the nanocomposites could be attributed to the stable interfacial interaction. A moderate percolation threshold was obtained at 0.41 vol% for the CNTs–CB/epoxy nanocomposites in comparison …

Meta-Analysis Of The Prevalence Of Dissolved Organic Nitrogen (Don) In Water And Wastewater And Review Of Don Removal And Recovery Strategies, Synthia P. Mallick, Zayed Mallick, Brooke K. Mayer

Civil and Environmental Engineering Faculty Research and Publications

Most wastewater removal and recovery processes primarily target dissolved inorganic nitrogen (DIN) species, leaving the untreated non-reactive dissolved organic nitrogen (DON) in the effluent. This DON fraction can account for a substantial part of the total nitrogen (N) load. We analyzed large datasets of N species and concentrations (with a focus on quantifying the fraction of DON) in surface water, ground water, and wastewater effluent across the United States. We then reviewed strategies to remove and recover DON based on results of a range of treatment technologies reported in the literature, including laboratory-scale up to full-scale operation in wastewater treatment …

Simple Rebar Anchorage Slip Macromodel Considering Corrosion, Ahmad Soraghi, Qindan Huang

Civil and Environmental Engineering Faculty Research and Publications

Reinforcement slip in the footing of a reinforced concrete (RC) column can significantly influence the lateral displacement of the column, a critical structural response under lateral loads such as seismic loading. Many past researchers studied and developed models to capture the anchorage slip of rebar; however, there is still a need for a model that can reflect the actual bond-slip relationship (especially in the presence of corrosion) and yet is simple-to-use for structural analysis. In this study, a simple bar stress-slip macromodel is developed to predict reinforcement anchorage slip given a rebar stress. The proposed rebar anchorage slip model is …

Lab-Scale Data And Microbial Community Structure Suggest Shortcut Nitrogen Removal As The Predominant Nitrogen Removal Mechanism In Post-Aerobic Digestion (Pad), Fabrizio Sabba, Patrick J. Mcnamara, Eric Redmond, Mike Young, Leon Downing

Civil and Environmental Engineering Faculty Research and Publications

Implementing an aerobic digestion step after anaerobic digestion, referred to as “post aerobic digestion” (PAD), can remove ammonia without the need for an external carbon source and destroy volatile solids. While this process has been documented at the lab-scale and full-scale, the mechanism for N removal and the corresponding microbial community that carries out this process have not been established. This research gap is important to fill because the nitrogen removal pathway has implications on aeration requirements and carbon demand, that is, short-cut N-removal requires less oxygen and carbon than simultaneous nitrification–denitrification. The aims of this research were to (i) …

Seasonal And Spatial Patterns Differ Between Intracellular And Extracellular Antibiotic Resistance Genes In Urban Stormwater Runoff, Kassidy N. O'Malley, Patrick J. Mcnamara, Walter M. Mcdonald

Civil and Environmental Engineering Faculty Research and Publications

Antibiotic resistance is a public health threat that is exacerbated by the dispersion of antibiotic resistance genes (ARGs) into aquatic environments. Urban stormwater runoff has been recognized as a source of and a mechanism by which intracellular ARGs (iARGs) can be transported into receiving environments. The prevalence and behavior of extracellular ARGs (eARGs) in stormwater, however, has yet to be considered. This study quantified four iARGs and eARGs under baseflow and stormflow conditions. Urban stormwater runoff was found to be a source of all the ARGs examined, with the absolute concentration of all iARGs and two eARGs (ermF …

Immobilized Phosphate-Binding Protein Systems To Remove And Recover Phosphate, Faten Bakri Hussein

Dissertations (1934 -)

Inorganic phosphorus (Pi) is a critical element for all life and a major component of DNA’s backbone. Global agriculture requires Pi to support the rapid growth of plants and high crop productivity. Yet, the mineable Pi supply needed for global agriculture is in short supply in nature and Pi reserves are unevenly distributed around the world. In contrast, surplus Pi in water poses a serious pollution problem as it can cause eutrophication. Scarcity of non-renewable Pi resources combined with pollution in the form of overabundant Pi presents a phosphorus paradox. Tackling this issue is necessary and using innovative approaches targeting …

Deep Learning-Based Prediction Of Ppb-Level Metal Ions In Drinking Water With Explainable Ai, Shaokun Yu

Master's Theses (2009 -)

In the research on detecting different ppb-level metal ions in drinking water in multiple areas. Through the block loop gap resonator (BLGR), this kind of metal ion sensor can continuously measure the concentrations of different metal ions in the water sample. The BLGR can classify different ions and measure the Cu and Pb ions in different ppb-level water in the city. According to the different magnitude and phases in continuous frequency in the testing. A better model can be trained by using deep learning, the convolution neural network. A neural network is often regarded as a black-box model because its …

Improving The Hardware Security Of Unmanned Aerial Vehicles Against Side Channel Analysis Using Motor Noise, Timothy Radtke

Master's Theses (2009 -)

This thesis investigates the efficacy of side channel analysis based attacks to recover the encryption key of unmanned aerial vehicles (UAV) which have become increasingly important internet of things devices in both the public and military sectors. Additionally, this thesis proposes a method based on noise injection to safeguard against side channel analysis based attacks. The proposed method is unique because it is ultra-low power and uses as a noise source the brushless motors of the unmanned aerial vehicle. Verification through experimentation on an in-house build UAV system is presented. Firstly, side channel analysis techniques are overviewed and the correlation …

A Design Process Leveraging Potential Energy In Planar Multistable Mechanisms, Edward Dold

Master's Theses (2009 -)

Planar multistable mechanisms are used throughout engineering to accomplish various tasks, for example residential electrical switching. The design of planar multistable mechanisms can be broken into four areas: determination of topology, geometric parameterization, analysis, and optimization. While topological determination, many analysis techniques, and optimization are well developed, geometric parameterization, which includes defining link lengths and spring stiffness, has largely been left to engineering judgement. This thesis presents a design methodology using potential energy graphs which informs engineering decisions made in choosing mechanism parameters for planar multistable mechanisms, giving designers higher confidence in the design. A kinematic analysis coupled with Lagrange's …

Device Location-Based Link Layer Scheduling For Large-Scale Dense Industrial Iot Networks, Ahmed Ajeena

Master's Theses (2009 -)

A medium access control (MAC) protocol design is proposed in this paper for the industrial internet of things (IIoT) networks with massive connections. Considering a non-fully connected network with multiple access points (APs), we aim to connect a large number of IIoT devices densely populating the network coverage area, achieve low latency, and avoid collisions. To achieve this objective, we adopt a time-slotted carrier sensing-based medium access control design and propose a device location-based time slot assignment scheme for channel access scheduling. The proposed scheme assigns devices to time slots based on their locations to eliminate collisions caused by hidden …

Seismic Performance Comparison Of Ordinary Concentrically Braced Frames In The Western And Central United States, Matthew Waters

Master's Theses (2009 -)

Ordinary concentrically braced frames (OCBFs) are intended to be moderately ductile steel seismic-force-resisting systems and are permitted in low-rise buildings in regions with high seismic hazards. There has been relatively little research to quantify the seismic performance of OCBFs, with most of the previous work emphasizing the role of reserve capacity on performance. To improve the understanding of seismic performance and validate current design provisions, a series of nonlinear response-history analyses were conducted. Two, three-story OCBF study buildings were designed in accordance with ASCE/SEI 7-16 for sites in Seattle, WA and Memphis, TN; the sites have relatively high seismic hazards …

Sequential Electrolysis And Reverse Osmosis To Improve Arsenic Removal From Water, Yizhi Hou, Brooke K. Mayer

Civil and Environmental Engineering Faculty Research and Publications

Reverse osmosis (RO) typically removes >98% arsenate (As[V]) but removes arsenite (As[III]) comparatively poorly (approximately 50%–80%). Therefore, oxidizing As(III) to As(V) can improve arsenic removal using RO. In this study, electrolytic oxidation was used to oxidize As(III) in the feed water, and an extreme low-pressure RO membrane was subsequently used to remove the arsenic. Using Ti/IrO2 electrodes under 30 mA DC current in 500 mg/L NaCl solution primarily generated free chlorine, which completely oxidized 300 μg/L As(III) to As(V). Subsequent arsenic removal by RO increased from 54.2% without oxidation to 98.2% with oxidation. Using electrolysis-RO, arsenic removal significantly increased beyond …

Semantic Representation Of Road Infrastructure Information, Tianjiao Zhao

Dissertations (1934 -)

A multi-sectoral collaboration completes a successful transportation infrastructure project. The cooperation involves designers, contractors, operators, users, government agencies, and maintenance staffs. Throughout the project's life cycle, a huge amount of data is generated and stored in various sectors. Therefore, an efficient information cross-sector exchange approach is necessary. Additionally, the World Wide Web is ubiquitous and enmeshed with multiple business processes. Therefore, it is imperative to represent business information in a format that improves information exchange as well as automated processing of business data. Ideally, road data scattered across different information sources, such as design software, geographic information systems (GIS), cost …

Novel Test Fixture For Characterizing Mems Switch Microcontact Reliability And Performance, Protap Kumar Mahanta

Dissertations (1934 -)

Microelectromechanical systems (MEMS) switch is considered as a better alternative than the conventional solid-state DC and RF switches due to their low contact resistance approximately 1 Ω, near-zero power consumption approximately 0 W, low insertion loss approximately 0.2 dB, and high isolation approximately -30 dB. However, reliability is a great concern for them to be ubiquitously used by the industry for specific applications. Switching dynamics and microcontact surface physics play the critical role in determining their reliability. A simple, quick, and efficient test fixture is required to study the contact surface physics as well as to optimize the switching dynamics.In …

Improved Management Of Recalcitrant Nutrient Species: Transformation And Adsorption, Synthia Parveen Mallick

Dissertations (1934 -)

Soluble non-reactive nutrient species, i.e., dissolved organic nitrogen (DON) and soluble non-reactive phosphorus (sNRP), are not effectively removed and recovered. Unfortunately, the non-reactive species can cause eutrophication in receiving waterbodies. Thus, removal and recovery of soluble non-reactive nutrients is critical for reducing nutrient discharge and advancing the national goal of enhanced nutrient recovery. Transformation of non-reactive nutrients to more readily removable/recoverable species using ozonation and UV/H2O2 for enhanced nutrient recovery has been reported in literature. Electrooxidation (EO) may outperform these processes in transforming nutrients as EO can utilize multiple oxidation pathways, e.g., in-situ generated oxidants or direct electron transfer (DET). …

Supermodal Decomposition Of The Linear Swing Equation For Multilayer Networks, Kshitij Bhatta, Amirhossein Nazerian, Francesco Sorrentino, Majeed M. Hayat

Electrical and Computer Engineering Faculty Research and Publications

We study the swing equation in the case of a multilayer network in which generators and motors are modeled differently; namely, the model for each generator is given by second order dynamics and the model for each motor is given by first order dynamics. We also remove the commonly used assumption of equal damping coefficients in the second order dynamics. Under these general conditions, we are able to obtain a decomposition of the linear swing equation into independent modes describing the propagation of small perturbations. In the process, we identify symmetries affecting the structure and dynamics of the multilayer network …

Identification And Quantitation Of Aqueous Single- And Multianalyte Solutions Of The Isomers Ethylbenzene, M-, P-, And O-Xylene Using A Single Specifically Tailored Sensor Coating And Estimation Theory-Based Signal Processing, Nicholas Post, Florian Bender, Fabien Josse, Edwin E. Yaz, Antonio J. Ricco

Electrical and Computer Engineering Faculty Research and Publications

The isomer-specific detection and quantitation of m-, p-, and o-xylene and ethylbenzene, dissolved singly and as mixtures in aqueous solutions at concentrations from 100 to 1200 ppb by volume, is reported for a specifically designed polymer-plasticizer coating on a shear-horizontal surface acoustic wave (SH-SAW) device. The polystyrene-ditridecyl phthalate-blend coating was designed utilizing Hansen solubility parameters and considering the dipole moment and polarizability of the analytical targets and coating components to optimize the affinity of the sensor coating for the four chemical isomers. The two key coating sorption properties, sensitivity and response time constant, are determined by the …

Electrothermal Design Of A Gan-Based Axially Stator Iron-Mounted Fully Integrated Modular Motor Drive, Armin Ebrahimian, Waqar A. Khan, S. Iman Hosseini, Nathan Weise

Electrical and Computer Engineering Faculty Research and Publications

The concept of More Electric Aircraft (MEA) has gained a lot of attention from researchers recently. For such an application, two of the pivotal requirements are having a power dense and energy efficient propulsion system. To that end, in the design procedure of the electric motor and its drive system, high power density and efficiency over the entire operating range is the ultimate goal. Thus, the integration of the electric motor and drive system into a single unit has been introduced as an effective method to meet the design objectives. Therefore, this paper presents the design procedure of a module …

Vibrotactile Perception For Sensorimotor Augmentation: Perceptual Discrimination Of Vibrotactile Stimuli Induced By Low-Cost Eccentric Rotating Mass Motors At Different Body Locations In Young, Middle-Aged, And Older Adults, Ella Pomplun, Ashiya Thomas, Erin Corrigan, Valay A. Shah, Leigh A. Mrotek, Robert A. Scheidt

Biomedical Engineering Faculty Research and Publications

Sensory augmentation technologies are being developed to convey useful supplemental sensory cues to people in comfortable, unobtrusive ways for the purpose of improving the ongoing control of volitional movement. Low-cost vibration motors are strong contenders for providing supplemental cues intended to enhance or augment closed-loop feedback control of limb movements in patients with proprioceptive deficits, but who still retain the ability to generate movement. However, it remains unclear what form such cues should take and where on the body they may be applied to enhance the perception-cognition-action cycle implicit in closed-loop feedback control. As a step toward addressing this knowledge …

The Value Of High Intensity Locomotor Training Applied To Patients With Acute-Onset Neurologic Injury, Meghan Fahey, Gabrielle Brazg, Christopher E. Henderson, Abby Plawecki, Emily H. Lucas, Darcy S. Reisman, Brian D. Schmit, T. George Hornby

Biomedical Engineering Faculty Research and Publications

The purpose of this review is to delineate some of the evidence regarding the effects of exercise intensity during locomotor training in patients with stroke and iSCI. We provide specific definitions of exercise intensity used within the literature, describe methods used to ensure appropriate levels of exertion, and discuss potential adverse events and safety concerns during its application. Further details on the effects of locomotor training intensity on clinical outcomes, and on neuromuscular and cardiovascular function will be addressed as available. Existing literature across multiple studies and meta-analyses reveals that exercise training intensity is likely a major factor that can …

A Porosity-Based Model Of Dynamic Compaction In Under-Dense Materials, John A. Moore, Nathan R. Barton

Mechanical Engineering Faculty Research and Publications

Under-dense metals including micro-architectured structures and stochastic foams provide a combination of low weight, high strength-to-weight ratio, high permeability, and low stiffness, which make them desirable materials for a variety of applications. Specifically, their energy absorption capabilities under dynamic compressive loads are desirable. However, under high loading rates there are several challenges in performing accurate simulations of under-dense materials—primarily, the responses of materials with high, low, and zero porosity are difficult to accurately predict with a single model. A general model that tracks porosity and pore geometry and is flexible for a variety of matrix material constitutive responses has yet …

Tensile Strain And Damage Self-Sensing Of Flax Frp Laminates Using Carbon Nanofiber Conductive Network Coupled With Acoustic Emission, Yanlei Wang, Guipeng Chen, Yongshuai Wang, Baoguo Han, Baolin Wan, Qingduo Hao, Yulei Bai

Civil and Environmental Engineering Faculty Research and Publications

The strain and damage self-sensing properties of carbon nanofibers (CNFs)/flax fiber-reinforced polymer (FFRP) laminates under tension were investigated via simultaneously measuring the changes of electrical resistance (ER) and acoustic emission (AE) signals. The piezoresistive mechanisms together with the damage evolution of CNFs/FFRP laminates were also explored. The results revealed that both ER and AE responses to tensile strains in CNFs/FFRP laminates could be segmented into three stages, which confirmed their good damage self-sensing ability. The isochronous and reversible electrical resistance responses to tensile strains proved the stability and repeatability of strain self-sensing capability for CNFs/FFRP laminates. Moreover, in-situ ER measurement …

Poly (5-Carboxyindole)–Β-Cyclodextrin Composite Material For Enhanced Formaldehyde Gas Sensing, John N. Hodul, Nikhil F. Carneiro, Allison K. Murray, Wilson Lee, Kelly M. Brayton, Xinping He, Carsten Flores-Hansen, Dimitry Zemlyanov, George T.-C. Chiu, James E. Braun, Bryan W. Boudouris, Jeffrey F. Rhoads

Mechanical Engineering Faculty Research and Publications

Formaldehyde, a compound commonly employed in many construction materials, paints, and plastics, has been linked to deleterious health effects. Thus, monitoring the presence of formaldehyde in interior locations is increasingly important when it comes to public health. Currently, there is a crucial need for a low-cost, small-scale, selective, and sensitive indoor sensor capable of real-time formaldehyde detection. To meet these performance metrics, materials need to be incorporated onto existing gas sensor platforms to act as chemically selective recognition layers. A main challenge when addressing this issue is creating a material that can remain easily processable, can be easily synthesized, and …

Development Of Probabilistic Failure Pressure Models For Pipelines With Single Corrosion Defect, Kiswendsida J. Kere, Qindan Huang

Civil and Environmental Engineering Faculty Research and Publications

Many models have been developed in the past to predict the failure pressure of a pipeline with a single corrosion defect. However, most of the existing models are conservative and may lead to unnecessary repairs and maintenance in the pipeline risk management. The aim of this study is to develop probabilistic failure pressure prediction models that are suitable for risk assessment of corroded pipelines. The proposed models are developed at three levels of pipe ultimate strength based on a comprehensive database (consist of both experimental and numerical data) established in this study. When comparing with the existing models, it is …

Hepatic Artery Flow, Inspired Oxygen, And Hemoglobin Determine Liver Tissue Saturation Measured With Visible Diffuse Reflectance Spectroscopy (Vis-Drs) In An In Vivo Swine Model, Stylianos Voulgarelis, Faraneh Fathi, Bing Yu, Barbara Palkovic, Nikolaos A. Chatzizacharias, Kenneth P. Allen, Astrid G. Stucke

Biomedical Engineering Faculty Research and Publications

Background

Prompt diagnosis of vascular compromise following pediatric liver transplantation and restoration of oxygen delivery to the liver improves organ survival. vis-DRS allows for real-time measurement of liver tissue saturation.

Methods

The current study used vis-DRS to determine changes in liver saturation during clinically relevant conditions of reduced oxygen delivery. In an in vivo swine model (n = 15), we determined liver tissue saturation (S_tO₂) during stepwise reduction in hepatic artery flow, different inspiratory oxygen fraction (FiO₂), and increasing hemodilution. A custom vis-DRS probe was placed directly on the organ.

Results

Liver tissue …

An Extraction Method To Quantify The Fraction Of Extracellular And Intracellular Antibiotic Resistance Genes In Aquatic Environments, Kassidy N. O'Malley, Walter M. Mcdonald, Patrick J. Mcnamara

Civil and Environmental Engineering Faculty Research and Publications

As the abundance and diversity of antibiotic resistance genes increases in the environment, there is a concurrent increase in the threat to public and ecosystem health. Extracellular antibiotic resistance genes (eARGs) are cell-free DNA that can promote the development of antibiotic resistance via transformation by competent bacterial cells. Despite this role, eARGs have not been well characterized in different environmental waters. Their small size and low concentrations in some aquatic environments render them difficult to extract. The aim of this research was to modify an eARG extraction method to determine the abundance of both eARGs and intracellular ARGs (iARGs) in …

Assessing Flooding Impact To Riverine Bridges: An Integrated Analysis, Maria Pregnolato, Andrew O. Winter, Dakota Mascarenas, Andrew D. Sen, Paul Bates, Michael R. Motley

Civil and Environmental Engineering Faculty Research and Publications

Flood events are the most frequent cause of damage to infrastructure compared to any other natural hazard, and global changes (climate, socioeconomic, technological) are likely to increase this damage. Transportation infrastructure systems are responsible for moving people, goods and services, and ensuring connection within and among urban areas. A failed link in these systems can impact the community by threatening evacuation capability, recovery operations and the overall economy. Bridges are critical links in the wider urban system since they are associated with little redundancy and a high (re)construction cost. Riverine bridges are particularly prone to failure during flood events; in …

Neural Correlates Of Multisensory Integration For Feedback Stabilization Of The Wrist, Aaron J. Suminski, Raymond C. Doudlah, Robert A. Scheidt

Biomedical Engineering Faculty Research and Publications

Robust control of action relies on the ability to perceive, integrate, and act on information from multiple sensory modalities including vision and proprioception. How does the brain combine sensory information to regulate ongoing mechanical interactions between the body and its physical environment? Some behavioral studies suggest that the rules governing multisensory integration for action may differ from the maximum likelihood estimation rules that appear to govern multisensory integration for many perceptual tasks. We used functional magnetic resonance (MR) imaging techniques, a MR-compatible robot, and a multisensory feedback control task to test that hypothesis by investigating how neural mechanisms involved in …

Comparison Of Cone Mosaic Metrics From Images Acquired With The Spectralis High Magnification Module And Adaptive Optics Scanning Light Ophthalmoscopy, Niamh Wynne, Heather Heitkotter, Erica N. Woertz, Robert F. Cooper, Joseph Carroll

Biomedical Engineering Faculty Research and Publications

Purpose: To compare cone mosaic metrics derived from adaptive optics scanning light ophthalmoscopy (AOSLO) images with those derived from Heidelberg Engineering SPECTRALIS High Magnification Module (HMM) images.

Methods: Participants with contiguous cone mosaics had HMM imaging performed at locations superior and temporal to the fovea. These images were registered and averaged offline and then aligned to split-detection AOSLO images; 200 × 200-µm regions of interest were extracted from both modalities. Cones were semi-automatically identified by two graders to provide estimates of cone density and spacing.

Results: Thirty participants with contiguous cone mosaics were imaged (10 males, 20 females; age range, …

Training The Responsible Conduct Of Research And Design, Jay R. Goldberg

Biomedical Engineering Faculty Research and Publications

Students Supported by grants from the National Institutes of Health (NIH) are required to complete training in the responsible conduct of research (RCR). This training includes topics such as authorship, handling of data, reporting of results, maintaining confidentiality, and other topics related to the ethical and responsible conduct of research. It prepares students who are supported by NIH research grants for careers involving research.