Engineering Commons^™

Efficacy Of Smart Pv Inverter As A Strategic Mitigator Of Network Harmonic Resonance And A Suppressor Of Temporary Overvoltage Phenomenon In Distribution Systems, Shriram Srinivasarangan Rangarajan

All Dissertations

The research work explores the design of Smart PV inverters in terms of modelling and investigates the efficacy of a Smart PV inverter as a strategic mitigator of network harmonic resonance phenomenon and a suppressor of Temporary Overvoltage (TOV) in distribution systems. The new application and the control strategy of Smart PV inverters can also be extended to SmartPark-Plug in Electric Vehicles as the grid becomes smarter.

As the grid is becoming smarter, more challenges are encountered with the integration of PV plants in distribution systems. Smart PV inverters nowadays are equipped with specialized controllers for exchanging reactive power with …

Coupled Hydrological-Geotechnical Model For Determinine Bearing Capacity And Elastic Settlement Of Foundations, Vahidreza Mahmoudabadi Arani

All Dissertations

This dissertation presents a coupled hydrological-geotechnical framework to investigate the performance of shallow and deep foundations under hydrological events such as heavy rainfall and drought. The variation in performance of foundation, interface between the structure and ground surface, is caused by the uncertainties associated with not only the geotechnical parameters but also the hydrological parameters that include intensity and duration of hydrological events and water table depth. The impact of such hydrological events significantly alters the performance of foundations by changing the soil strength and stiffness parameters of subsurface soil which may lead to foundation failures. Such failures can cause …

Seismic Vulnerability Assessment Of Buildings Using A Statistical Method Of Response Prediction, Ershad Ziaei, Amir Safiey, Weichiang Pang, Keivan Rokneddin, Mohammad Javanbarg, Mengzhe Gu

Publications

The seismic vulnerability functions for portfolio-level loss estimation are typically developed for general classes of buildings which may not be suitable to assess building-specific risks. Performance-based earthquake engineering (PBEE) provides the means to conduct building-specific seismic risk assessments. However, such assessments often rely on computationally-intensive analytical frameworks such as incremental dynamics analysis (IDA) which poses a challenge for many types of risk assessment projects. To expand its accessibility, FEMA P-58 outlines a simplified method to predict the nonlinear responses of buildings in which the scope is limited to lower levels of inter-story drifts (less than 4%). This limitation restricts its …

Influence Of Irreparability Fragility On Seismic Vulnerability Assessment Of Buildings, Amir Safiey, Ershad Ziaei, Mengzhe Gu, Weichiang Pang, Keivan Rokneddin, Mohammad Javanbarg

Publications

The probability that a building is sanctioned to demolition following an earthquake depends on several geotechnical, structural, strategic and financial decision variables. This paper explores the literature on post-earthquake reparability assessment of buildings focusing on structural characteristics and evaluates their approaches for four midrise code-compliant structural systems, namely, steel moment frame, reinforced concrete moment frame, light frame wood, and steel braced frame. The structural responses are estimated using incremental dynamics analysis (IDA) in accordance with FEMA P-695 provisions and the IDA results are relayed to a building-specific loss assessment framework to estimate their seismic vulnerability in terms of monetary losses. …

Cure History Dependent Viscoelastic Modeling Of Adhesively Bonded Joints Using Mat_277 In Ls-Dyna®, Akshat Agha, Fadi Abu-Farha, Rakan Alturk, Tim Welters, Georges Romanos

Publications

The effects of Coefficient of Thermal Expansion (CTE) mismatch in multi-material adhesive joints, induced during the manufacturing process, are expected to hinder the peak performance of the adhesive in the service life of the vehicle. With a goal to estimate these effects, this paper attempts to model the curing phenomenon of an adhesive and predict its mechanical properties using MAT_277 material model available in LS-DYNA, which serves as a good starting point towards modeling the cure history dependent viscoelastic behavior of adhesives. The adhesive is used to join two substrates of dissimilar metals and tested to capture the relative displacement …

Ph-Responsive Mercaptoundecanoic Acid Functionalized Gold Nanoparticles And Applications In Catalysis, Siyam M. Ansar, Saptarshi Chakraborty, Christopher L. Kitchens

Publications

Mercaptoundecanoic acid (MUA) functionalized gold nanoparticles (AuNP-MUA) were synthesized and demonstrated to possess pH-triggered aggregation and re-dispersion, as well as the capability of phase transfer between aqueous and organic phases in response to changes in pH. The pH of aggregation for AuNP-MUA is consistent with the pK_a of MUA (pH ~4) in solution, while AuNP-MUA phase transition between aqueous and organic phases occurs at pH ~9. The ion pair formation between the amine group in octadecylamine (ODA), the carboxylate group in MUA, and the hydrophobic alkyl chain of ODA facilitates the phase transfer of AuNP-MUA into an organic medium. …

Regeneration Of The Ventricular Endocardium Within Acellular Whole Rabbit Hearts Using A Layer-By-Layer Seeding Method, Clayton Lewis Compton

All Theses

In the United States, 1 out of every 9 death certificates in 2013 referenced heart failure.1 Despite the outstanding need of treatment options for heart failure, heart transplantation remains the optimal treatment method. However, there is a severe shortage of donor hearts available for transplantation.2 Other available treatment options are not ideal because they do not fully restore function and are associated with creating other complications.3 Thus, there is a need for developing a living tissue engineered whole heart for transplantation to provide an alternative option for patients on the waitlist to receive a donor heart.

Our solution is to …

Simulation Of The Behavior Of Corrosion Damaged Reinforced Concrete Beams With/Without Cfrp Retrofit, Masoud Zabihi-Samani, Mohsenali Shayanfar, Amir Safiey, Amir Najari

Publications

Harsh environmental conditions along with aggressive chemical agents are known as one of the main reasons behind damages observed in reinforced concrete members. Corrosion of reinforcement worldwide is one of the leading causes of damages occurred in reinforced concrete over the lifespan. There are many critical energy and transportation infrastructures located on coastal regions exposed to high humidity and chloride content where they are highly prone to reinforcement corrosion. This calls for retrofit methods, which safeguard not only the strength but also the durability of corrosion deteriorated reinforced concrete structures. Carbon fiber polymers considering their mechanical and chemical properties are …

Non-Newtonian Fabric-Fluid Composites: Fabrication, Characterization And Testing For Anti-Ballistics Applications, Hayley M. Weir

All Theses

This thesis aims to characterize non-Newtonian suspensions for anti-ballistics applications. This involves characterizing the rheological behavior of each suspension. It also includes characterizing the interactions of the suspensions with several types of fabrics with known antiballistics properties. The study also tests the armor composites under ballistics stresses by firing on them with standardized military weaponry. This data is then compiled to determine which, if any, of the fabrics and suspensions are ultimately suitable for anti-ballistics uses.

The Professional Constructor, Full Issue, Volume 43, Number 01

The Professional Constructor

No abstract provided.

A Complementary Cyber-Human Systems Framework For Industry 4.0 Cyber-Physical Systems, Matthew Krugh, Laine Mears

Publications

Humans are a vital element to automotive manufacturing; however, skilled production personnel have largely been designated as data receivers in Cyber-Physical Systems (CPS) of Industry 4.0. A renewed focus on the human worker who completes significant portions of manual value-added content in automotive assembly through Cyber-Human Systems (CHS) is allowing humans to perform their jobs more safely, efficiently, and supporting enhanced control and quality monitoring of manual manufacturing tasks. There is a need for a unified complementary framework of CHS and CPS to guide the implementation of future smart manufacturing systems.

Cardiovascular Biomechanical Models, Ethan Kung

Publications

Computational and in vitro methods offer powerful means to model the cardiovascular system and investigate biomechanics related to blood flow, cardiovascular tissue, and medical devices. These models can be constructed to directly describe human anatomy and physiology, and can be more highly controlled compared to animal models. Low-order models composed of lumped-parameter elements and simplified descriptions of cardiac function can capture the global physiology, while high-order models exhibiting detailed 3D anatomy and dynamics can provide highly realistic replication of biomechanical interactions in a small region of the circulation. Multiscale models offer the freedom to capture biomechanics in different regions at …

Increase In The Reduction Potential Of Uranyl Upon Interaction With Graphene Oxide Surfaces, V. N. Bliznyuk, N. Conroy, Y. Xie, R. Podila, A. Rao, Brian A. Powell

Publications

Coordination of uranyl (U(VI)) with carboxylate groups on functionalized graphene oxide (GO) surfaces has been shown to alter the reduction potential of the sorbed uranium ion. A quantitative measure of the reduction potential and qualitative estimation of sorption/desorption processes were conducted using cyclic voltammetry, and the proposed coordination environment was determined using the surface sensitive attenuated total reflection mode of infrared spectroscopy (ATR-FTIR). GO is a nanostructured material possessing a large amount of oxygen-containing functional groups both on basal planes and at the edges, which can form strong surface complexes with radionuclides. The presence of these functional groups on the …

Graphene Field Effect Transistors For Highly Sensitive And Selective Detection Of K+ Ions, Hongmei Li, Yihao Zhu, Md. Sayful Islam, Md. Anisur Rahman, Kenneth B. Walsh, Goutam Koley

Publications

Graphene-based ion sensitive field effect transistors (GISFETs) with high sensitivity and selectivity for K+ ion detection have been demonstrated utilizing valinomycin based ion selective membrane. The performance of the GISFETs for K+ ion detection was studied in various media over a concentration range of 1 μM–2 mM. The sensitivity of the sensor was found to be >60 mV/decade, which is comparable to the best Si-based commercial ISFETs, with negligible interference found from Na+ and Ca2+ ions in high concentration. The sensor performance did not change significantly in Tris–HCl solution or with repeated testing over a period of two months highlighting …

Extended Lamer Synthesis Of Cobalt Doped Ferrite, Benjamin D. Fellows, Sarah Sandler, Jacob Livingston, Kristin Fuller, Lotanna Nwandu, Sarah Timmis, Kayla A. Lantz, Morgan Stefik, O. Thompson Mefford

Publications

Nonstoichiometric cobalt ferrite nanoparticles have drawn interest in magnetically mediated energy delivery due to their high magnetocrystalline anisotropy and their high peak loss frequency. The use of an extended LaMer synthesis allows for size control of the doped particles up to a threshold core diameter of 18 nm. Above this diameter, particles become unstable and drop out of suspension, allowing for further nucleation events to occur. This leads to a cyclic nucleation, growth, and destabilization regime seen during the course of the reaction. Using the size control of the extended LaMer synthesis technique, we examine the specific absorption rate (SAR) …

A Globally Stable Attractor That Is Locally Unstable Everywhere, Phanindra Tallapragada, Senbagaraman Sudarsanam

Publications

We construct two examples of invariant manifolds that despite being locally unstable at every point in the transverse direction are globally stable. Using numerical simulations we show that these invariant manifolds temporarily repel nearby trajectories but act as global attractors. We formulate an explanation for such global stability in terms of the ‘rate of rotation’ of the stable and unstable eigenvectors spanning the normal subspace associated with each point of the invariant manifold. We discuss the role of this rate of rotation on the transitions between the stable and unstable regimes.

Determination Of Safe Ballasts For Anchoring Event Tents By Finite Element Analysis, Sandeep Manoharan

All Theses

Event tents are large structures made of fabric covers attached to a structural frame and poles. Every year, many temporarily installed tents are subjected to large wind conditions that lead to sliding or lift of the frame due to improper anchoring to the ground. When ballasted, as opposed to anchored using stakes that penetrate the ground, non-certified tents are generally installed without proper analysis of sufficient ballast weights, which results into tent movements and lack of safety. The objective of this thesis is to determine load factors for non-certified tents affected by high wind loads. The load requirements (load factors) …

Micro-Cantilever Based Fiber Optic Hydrophone, Jie Liu

All Dissertations

Endoscopic photoacoustic imaging probe is becoming increasingly important for many clinical photoacoustic imaging applications in which the target tissue can only be accessed by introducing an endoscopic probe percutaneously or through a natural orifice. Miniature fiber optic hydrophone (FOH) has become an attractive choice for endoscopic photoacoustic imaging application. Fiber optic hydrophone has many proven advantages, including small size, light weight, immunity to electromagnetic interference, low cost for single-use application and capability of integration of excitation light source and acoustic wave receiver.

This dissertation demonstrates an open cavity, micro-cantilever based fiber optic Fabry-Perot interferometer (FPI) hydrophone. A fused silica micro-cantilever …

Synthesis And Characterization Of Glycidyl Methacrylate-Based Graft Copolymer Functional Interfaces, Nikolay Brordinov

All Dissertations

Modification of materials properties such as surface energy, wettability, ability to absorb, contain or release specific type of chemicals enables practical application of these materials in various scientific and engineering set-ups. However, designing protocol that could be easily adapted for different situations and simultaneously unlock multiple variations of the resulting properties is a non-trivial task. This dissertation is devoted to application of glycidyl methacrylate-based graft copolymers for the purposes of surface modification, establishing fundamental trends and dependencies of this process and exploring the possible range of applications. These materials have extremely valuable property to undergo controllable post-synthetic modifications including surface …

A Comparative Study On The Durability Of Geopolymer Mortars Produced With Ground Glass Fiber, Fly Ash, And Glass-Powder In Sodium Sulfate Solution, Hassan Rashidian-Dezfouli, Prasada Rao Rangaraju

Publications

An experimental investigation was conducted to investigate the performance of geopolymers made with three different precursors consisting of fly ash, Ground Glass Fiber (GGF), and Glass-Powder (GLP) exposed to sodium sulfate solution. Precursors were activated using either sodium hydroxide solution or combinations of sodium hydroxide and sodium silicate solution with varying levels of sodium and silica content. Among the mixtures with each of the three precursors, mortar mixtures with the highest compressive strength were selected to test their resistance against exposure to a 5% sodium sulfate solution. Changes in the weight and compressive strength of the specimens were monitored up …

Multiscale Modeling Of Cardiovascular Flows, Alison Marsden, Ethan Kung

Publications

Simulations of blood flow in the cardiovascular system offer investigative and predictive capabilities to augment current clinical tools. Using image-based modeling, the Navier-Stokes equations can be solved to obtain detailed 3-dimensional hemodynamics in patient-specific anatomical models. Relevant parameters such as wall shear stress and particle residence times can then be calculated from the 3D results and correlated with clinical data for treatment planning and device evaluation. Reduced-order models such as open or closed loop 0D lumped-parameter models can simulate the dynamic behavior of the circulatory system using an analogy to electrical circuits. When coupled to 3D simulations as boundary conditions, …

An Investigation Of Information Sought By Caregivers Of Alzheimer’S Patients On Online Peer-Support Groups, Emma Scharett, Kapil Chalil Madathil, Snehal Lopes, Hunter Rogers, Sruthy Agnisarman, Shraddhaa Narasimha, Aparna Ashok, Cheryl Dye

Publications

Alzheimer’s caregivers seek social support through online communities to deal with their issues. The research team conducted a content analysis of ALZConnected.org to investigate the characteristics of information searched by caregivers and responses received. Two-hundred fifty posts and related responses were randomly selected and analyzed using a classification tool derived from the analysis of 500 posts and related responses spanning a yearlong period. The Linguistic Inquiry and Word Count (LIW C) generated an average tone rating of 25.94 for the posts and 52.69 for the responses. The findings highlighted the caregiver’s need for emotional support (59.6%), and confusion about Alzheimer’s …

Role Of Surface Factors On Heterogeneous Ice Nucleation, Brittany Glatz

All Dissertations

Heterogeneous ice nucleation is the primary pathway for ice formation. However, the detailed molecular mechanisms by which surfaces promote or hinder ice nucleation are not well understood. We present results from extensive molecular dynamics and forward flux sampling (FFS) simulations of ice nucleation near modified surfaces. The surfaces are modified to investigate the effects of different surface factors on the rate and mechanism of ice nucleation. We find that the surface charge distribution has significant effects on ice nucleation. We also investigate the interplay of surface lattice and hydrogen bonding properties in affecting ice nucleation. We find that lattice matching …

The Professional Constructor, Full Issue, Volume 42, Number 02

The Professional Constructor

No abstract provided.

Convergence Of The Fast State Estimation For Power Systems, Md Ashfaqur Rahman, Ganesh Kumar Venayagamoorthy

Publications

Power system state estimation is a fundamental computational process that requires both speed and reliability. To meet the needs, some variants of the constant Jacobian methods have been used in the industry over the last several decades. The variants work very well under normal operating conditions with nominal values of the states. However, the convergence of the methods are not analysed mathematically and it may contain pitfalls. In this study, the convergence of the constant Jacobian methods are analysed and it is shown that the methods fail under high variations of the states. To increase the reliability of the processes, …

A Sustainable Approach For Tungsten Carbide Synthesis Using Renewable Biopolymers, Monsur Islam, Rodrigo Martinez-Duarte

Publications

Here we present a sustainable, environment-friendly and energy-efficient approach for synthesis of porous tungsten carbide (WC). A biopolymer-metal oxide composite featuring iota-carrageenan, chitin and tungsten trioxide (WO3) was used as the precursor material. The reaction mechanism for the synthesis of WC was estimated using the results from X-ray diffraction characterization (XRD). A synthesis temperature of 1300 °C and dwell time of 3 h were found to be the optimum process parameters to obtain WC>98% pure. The grain size, porosity and Brunauer–Emmett–Teller (BET) surface area of the synthesized WC were characterized using field emission scanning electron microscopy, high resolution transmission …

Lb3d: A Parallel Implementation Of The Lattice-Boltzmann Method For Simulation Of Interacting Amphiphilic Fluids, S. Schmieschek, L. Shamardin, S. Frijters, T. Krüger, U. D. Schiller, J. Harting, P. V. Coveney

Publications

We introduce the lattice-Boltzmann code LB3D, version 7.1. Building on a parallel program and supporting tools which have enabled research utilising high performance computing resources for nearly two decades, LB3D version 7 provides a subset of the research code functionality as an open source project. Here, we describe the theoretical basis of the algorithm as well as computational aspects of the implementation. The software package is validated against simulations of meso-phases resulting from self-assembly in ternary fluid mixtures comprising immiscible and amphiphilic components such as water–oil–surfactant systems. The impact of the surfactant species on the dynamics of spinodal decomposition are …

Forces And Disease: Electrostatic Force Differences Caused By Mutations In Kinesin Motor Domains Can Distinguish Between Disease-Causing And Non-Disease-Causing Mutations, Lin Li, Yunhui Peng, Subash Godar, Ivan Getov, Shaolei Teng, Joshua Alper, Emil Alexov

Publications

The ability to predict if a given mutation is disease-causing or not has enormous potential to impact human health. Typically, these predictions are made by assessing the effects of mutation on macromolecular stability and amino acid conservation. Here we report a novel feature: the electrostatic component of the force acting between a kinesin motor domain and tubulin. We demonstrate that changes in the electrostatic component of the binding force are able to discriminate between disease-causing and non-disease-causing mutations found in human kinesin motor domains using the receiver operating characteristic (ROC). Because diseases may originate from multiple effects not related to …

Impacts Of Rail Transit Investments On Demographics And Land Use: 1990-2010, Aubrey Trinidad

All Theses

This paper studies the changes in land use and population characteristics around station areas following the building of rail transit stations in 14 major cities in the United States from 1990 to 2010. It answers the question: how have investments in US rail transit made since the 1990s affected land use and demographics? It also looks at the specific effects of investments on population density, race, and ethnicity, means of transportation, median housing value, median household income, vehicle access share, occupations, and land use represented by the share of multifamily versus single-family housing. Using block group level US census data …

The Effect Of Surface Roughness Modifications And Chitosan Surface Coatings On Biofilm Formation For Prevention Of Orthopaedic Infections, Nathan Dewayne Smith

All Theses

Infections have been reported to occur in up to 91% of patients after orthopaedic procedures. Many of these infections are caused by bacterial biofilm growth on the surface of the implanted device. Surface modifications of fracture fixation implants have been taken into consideration in order to reduce infection rates and improve clinical results in orthopaedic procedures. Effective surface treatments will also reduce the need for antibiotics and prevent formation of drug-resistant bacteria. Titanium alloy sample discs (N=144) were prepared with six surface roughness treatments through polishing as well as with four different concentrations of chitosan through spin coating. In vitro …