Engineering Commons^™

Verification And Validation Of Power Converters For Use In Future Power System Architectures, Alexander Johnston

Electrical Engineering Dissertations - Archive

Electronics are more widely penetrating almost every area of society and as they do, the demand to supply them with regulated power increases considerably. The scale of the electronic power distribution systems needed ranges from those in very small handheld consumer electronic devices all the way up to those needed in large buildings, ships, and cities. The energy supplied within these power distribution systems can come from many different generation sources that operate either individually or simultaneously. When power electronics are controlled properly, simultaneous generation sources can be employed in a way that optimizes them according to the user’s desired …

Evaluation And Modeling Of Power System Components, Zachary Ryan Bailey

Electrical Engineering Dissertations - Archive

Future power system architectures will rely on a combination of rotating machines, power electronic devices, and energy storage. While it is possible to procure each component separately and conduct studies incorporating these devices into a system, increases in computing power and advanced computer modeling software have expanded the opportunity for research to be conducted on power system architectures without the need for actual hardware. This provides flexibility by allowing the user to design models of individual components that can then be integrated together or effortlessly interchanged depending on the function or testbed design that is being studied. The UTA IDEAL …

Integrating Fire Responses To Combat Wildfires, Jonathan Leonard Badal

Electrical Engineering

Each year wildfires cause significant loss of property, worsen people’s health, and destroy multiple ecosystems. On average, a wildfire season costs anywhere from 7.6-62.8 billion dollars due to fire containment, repair, and restoration [1]. It can take decades to recover from the crippling loss of land and take even longer to fully restore it. However, with the implementation of a robust early detection system, these losses can be significantly reduced. The current process for identifying wildfires involves visual identification, phone call alerts, and media tools primarily driven by park rangers and public reporting. Unfortunately, this system is not preventative and …

Development Of Modeling And Simulation Platform For Path-Planning And Control Of Autonomous Underwater Vehicles In Three-Dimensional Spaces, Sai Krishna Abhiram Kondapalli

Mechanical & Aerospace Engineering Theses & Dissertations

Autonomous underwater vehicles (AUVs) operating in deep sea and littoral environments have diverse applications including marine biology exploration, ocean environment monitoring, search for plane crash sites, inspection of ship-hulls and pipelines, underwater oil rig maintenance, border patrol, etc. Achieving autonomy in underwater vehicles relies on a tight integration between modules of sensing, navigation, decision-making, path-planning, trajectory tracking, and low-level control. This system integration task benefits from testing the related algorithms and techniques in a simulated environment before implementation in a physical test bed. This thesis reports on the development of a modeling and simulation platform that supports the design and …

Advances In Process Understanding And Methods To Support River Temperature Modeling In Large Regulated Systems, Bryce A. Mihalevich

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

River temperatures play a key role in determining the suitability of habitat for aquatic ecosystems. While thermal regimes are influenced by many factors, flow and temperature patterns in large rivers are often shaped by water development. As such, water management associated with large reservoirs and diversions have also altered aquatic ecosystems. As climate change introduces new climate and hydrologic patterns, the decisions water managers make to address changes in runoff may further impact aquatic ecosystems. This calls for robust modeling tools that can predict river and reservoir temperature responses to water management decisions over large regions. However, highly variable topography …

Risk-And-Resiliency-Intelligent Supply Chain (Rrisc), Ahmad A. Abdelnabi, Ahmed M. Abdelmagid, Ghaith Rabadi, Andres Sousa-Poza, C. Ariel Pinto

Modeling, Simulation and Visualization Student Capstone Conference

This work proposes a risk-and-resiliency-intelligent supply chain (RRiSC) tool which is an SC risk management framework that leverages cutting-edge technologies in Artificial Intelligence (AI), Big Data Analytics (BDA), and Digital Twins (DT) to develop specific capabilities for SC risk management. RRiSC is a convergence of mature tools and techniques embedded in three modules: Modeling, Simulation, and Visualization – all together integrate the optimization, simulation, and data analytics to test the performance of the whole supply network under different scenarios through measuring the vital KPIs, identifying the vulnerabilities, and setting proactive plans to diminish risks consequences.

Literature Review On The Discrete Element Method In Asphalt Mixtures, Hui Yao, Mei Xu, Junfu Liu, Yu Liu, Jie Ji, Zhanping You

Michigan Tech Publications, Part 1

Asphalt mixtures are commonly used in pavement engineering, especially for highway construction. The mechanism exploration and analysis of pavement distress are the main challenges for researchers and industry managers. Thereby, it is important to understand their properties and interaction mechanisms in asphalt mixtures. It is difficult to conduct some sophisticated or microscale tests in the laboratory, and numerical simulation and virtual tests can be solutions for these cases with low costs. The Discrete Element Method (DEM) is a promising tool for researchers to undertake these tasks. This paper mainly summarized and analyzed the research progress and development prospect of DEMs …

Parametric Models Of Maize Stalk Morphology, Michael Alan Ottesen

Theses and Dissertations

As the most produced grain crop world-wide, 5% of corn is lost due to stalk lodging (above-ground structural failure of the stalk near the roots). Current modeling methods lack the ability to manipulate the stalk architecture. In contrast, parameterized models enable advanced analyses such as sensitivity and optimization studies. This thesis advances previous work on a parameterized cross-sectional model of maize stalk morphology and investigates the validity of a parameterized three-dimensional model. The parameterized cross-sectional model is based upon previous work that approximated the cross-section of maize stalks using an ellipse plus principal components. Validation of the cross-sectional model was …

Understanding The Nonlinear Dynamics Governing Vertical-Lift Vehicles With Variable-Speed, Fixed Rotors, Stephanie Vavra, Micah Busboom, Aleea Stanford, Keegan Moore

UNL Student Research Days Posters, Undergraduate

Problem: Traffic significantly limits travel in urban areas. • The NASA Urban Air Mobility Project is developing an air taxi as an alternative mean of transportation (Fig. 1).

Challenge: Operating rotors at different frequencies may cause the cabin to vibrate at high amplitudes. Such effects are currently unknown.

Objective: Understand the effect of variable speed rotors on passenger comfort.

From the reduced-order modeling simulations, it can be assumed that counteracting the rotor speed in-balances can reduce the displacement and vibrations experienced at the center of the wing. In other words, should a rotor not maintain its optimal operation speed, reducing …

Mathematical Modeling Of The Solvent Extraction Of Palm Kernel Oil From Palm Kernel, Omeiza James Momoh James Momoh, David O. Obada

Palestine Technical University Research Journal

The model for the solvent extraction of palm kernel oil from palm kernel was generated for the process at varying particle sizes of palm kernel, temperature of extraction, duration of extraction and mass of palm kernel respectively using Least Square Linear Equation. Petroleum ether was used as solvent to carry out the extraction in a soxhlet apparatus. The percentage oil yield was determined for every extraction carried out. The experimental results obtained showed that percentage oil yield decreases with increase in particle size and mass, but increases with increase in the temperature and duration of extraction. The characterization of the …

Modelling Of Reаctive Distillаtion Process For Etherificаtion Reаction, Adham Norkobilov, Olimjon Mаksudov, Abdulaziz Bаkhtiyorov, Orifjon Zаripov, Abbos Elmаnov

CHEMISTRY AND CHEMICAL ENGINEERING

А reаctive distillаtion system is exаmined to produce for the production of Ethyl tert butyl ether (ETBE) viа etherificаtion of isobutene with ethаnol. Optimizаtion methods using heаt integrаtion аre аlso conducted. The molаr reflux rаtio аnd reboiler duty аre cаlculаted using sensitivity аnаlysis. The bottom streаm with the sаtisfied purity of ETBE is integrаted for heаting the feed streаm to the column. Heаt integrаtion from reаctor heаt to the initiаl feed streаm аnd from bottom streаm of the column to the column inlet streаm with the purpose of аchieving tаrget feed temperаture leаds to high conversion in the reаctive distillаtion …

Track Deception Modeling Method Based On Multi-Jammer Cooperation, Wang Rui, Xiangyang Li, Zhili Zhang, Hongguang Ma

Journal of System Simulation

Abstract: The false track generated by the jammer formation is an effective interference measure against networked radars. This paper starts from the basic principle of false track generation and presents the model of the measurement error of the radar for the false track and the control error of the jammer formation. It also presents an analysis of the effects of these errors on the false track. The effectiveness of the false track is further analyzed through the confrontation scenario between the rectangular front formation of a certain type of equipment and networked radars. The simulation results show that the false …

Research On Digital Twin-Based Modeling And Monitoring Of Five-Axis Grinder, Xiao Tong, Haifan Jiang, Guofu Ding, Jiang Lei, Shuwen Ma

Journal of System Simulation

Abstract: Aiming at the poor virtual-real interaction ability, single data presentation mode, and hysteretic abnormality handling in CNC machine tool status monitoring, a visual monitoring method for machine tool process based on digital twin is proposed, Which realizes the mapping of three subsystems of machine tool, machinery, control and electrical to the information space from three dimensions of geometry, logic and data. The verification of instructions and CNC programs, real-time status monitoring and abnormality handling during operation are carried out. A digital twin-based machine tool modeling and monitoring system is designed and developed. Taking a five-axis CNC …

Resonance Analysis Between Deck And Cables In Cable-Stayed Bridges With Coupling Effect Of Adjacent Cables Considered, Houjun Kang, Yunpeng Cai, Yunyue Cong, Xiaoyang Su, Guirong Grace Yan

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The nonlinear dynamic model of a shallow arch with multiple cables is developed to model a long-span cable-stayed bridge. Based on the veering phenomenon of cable-stayed bridges, the in-plane modal internal resonance between the first mode of the shallow arch and the first mode of the cable is investigated under both primary resonance and subharmonic resonance. Modulation equations of the dynamic system are obtained by Galerkin discretization and the multiple scales method, in which the equilibrium solution of modulation equations is obtained by the Newton–Raphson method. Meanwhile, the Runge–Kutta method is applied to directly solve the ordinary differential equations to …

Exploring Blockchain Adoption Supply Chains: Opportunities And Challenges, Adrian V. Gheorghe, Omer F. Keskin, Farinaz Sabz Ali Pour

Engineering Management & Systems Engineering Faculty Publications

In modern supply chains, acquisition often occurs with the involvement of a network of organizations. The resilience, efficiency, and effectiveness of supply networks are crucial for the viability of acquisition. Disruptions in the supply chain require adequate communication infrastructure to ensure resilience. However, supply networks do not have a shared information technology infrastructure that ensures effective communication. Therefore decision-makers seek new methodologies for supply chain management resilience. Blockchain technology offers new decentralization and service delegation methods that can transform supply chains and result in a more flexible, efficient, and effective supply chain. This report presents a framework for the application …

Development Of A Framework To Support Informed Shipbuilding Based On Supply Chain Disruptions, Katherine Smith, Rafael Diaz, Yuzhong Shen

VMASC Publications

In addition to stresses induced by the Covid-19 pandemic, supply chains worldwide have been growing more complex while facing a continuous onslaught of disruptions. This paper presents an analysis and extension of a graph based model for modeling and simulating the effects of such disruptions. The graph based model combines a Bayesian network approach for simulating risks with a network dependency analysis approach for simulating the propagation of disruptions through the network over time. The initial analysis provides evidence supporting extension to for using a multi-layered approach allowing for the inclusion of cyclic features in supply chain models. Initial results …

Sources Of Variability And Uncertainty In Food-Energy-Water Nexus Systems, Heydi Calderon-Ambelis, Deepak R. Keshwani

Department of Agricultural and Biological Systems Engineering: Faculty Publications

A nexus approach contributes to the strategic allocation of resources to secure food, energy, and water for the world population. Integrated models considering the complex interactions across food, energy, and water (FEW) enhance decision-making and strategic planning towards resilience. However, a significant number of the existing integrated models leave unaddressed the inherent variability and uncertainty present in the FEW sectors. Here, we review the importance of characterizing variability over spatial and temporal scales and the importance of decreasing the uncertainty present within a FEW nexus systems. The review also discusses existing modeling tools that address variability and uncertainty on single …

Characterization And Modeling Of Esd Events, Risk And Protection, Jianchi Zhou

Doctoral Dissertations

“The ESD (Electrostatic discharge) failures have been raising critical reliability problems in electronic devices design. However, not all the ESD scenarios have been specified by the IEC standard and the characterizations of the ESD risk for different scenarios are essential to evaluate the ESD robustness of the devices in the real word.

The insulation of plastic enclosures provides protection against ESD to the electronic system inside. However, seams between plastic parts are often unavoidable. Different plastic arrangements are constructed to investigate the spark length and current derivatives and to understand the ESD spark behavior for geometries having spark lengths longer …

Electromechanical Mechanisms Of Electromigration - Novel Approaches, Raghavendra Rao Morusupalli

All ETDs from UAB

Reliability of today’s interconnect lines in microelectronic devices is critical to product lifetime. The metal interconnects are carriers of large current densities and mechanical stresses, which can cause void formation or metal extrusion into the passivation leading to failure. The modeling and simulation of stress evolution caused by electromigration in interconnect lines and vias can provide a means for predicting the time to failure of the device. Reliability and performance are equally important in the microelectronics industry of today. Product lifetimes are expected to be as high as 10 to 15 years of service. A typical microprocessor has millions of …

A Value-Based Framework For Process Alignment In Complex Provisioning Systems, Michael Lipscomb

All ETDs from UAB

Provisioning systems are human-built, process-based systems whose activities are directed toward providing something of value to another entity. The things provided are not limited to any one type but may include, for example, objects, services, and information. Systems under consideration herein are limited to those that are human based, decentralized, and complex. “Human based” means that many of the agents and all the customers of the system are human. “Decentralized” means that agents act beyond central control. Such a system presents different challenges from one in which tasks are delegated from a central authority. In a decentralized system, agents are …

Modeling The Effects Of Parameter Changes On Heating And Pressure At The Weld Interface And Joint Strength In Friction Bit Joining, Adam Hartly Wagner

Theses and Dissertations

Joining of dissimilar metals is a process that is of interest in many fields, especially the automotive industry where lightweighting of the body structure is important. However, creating strong joints between dissimilar metals can be challenging. Friction bit joining (FBJ) is a solid-state method that uses a consumable bit to create a strong joint between dissimilar metals such as aluminum and steel. The purpose of this research is to gain understanding of how adjusting FBJ parameters affects the heating and pressure at the weld interface using a modeling approach, in order to better understand the bonding process. The questions guiding …

Development And Validation Of An Analytical Modeling Tool For Solar Borehole Heat Exchangers, Adam Ornelles

All Theses

Current numerical modeling solutions used for subsurface heat flow, such as the Berkeley TOUGH codes, are often difficult to use and time-consuming compared to analytical modeling methods. However, current analytical modeling methods for subsurface heat flow and groundwater cannot accurately model the subsurface in 3 dimensions, a feature paramount to the planning and installation of thermal borehole heat exchangers used in environmental remediation.

This research developed a novel 3-dimensional analytical modeling tool for solar-powered borehole heat exchangers. The analytical modeling tool can plan thermal remediation systems while being more straightforward to operate than current numerical modeling software. By creating a …

Investigation Of Control Parameters, Strategies, And Transport Modeling For Effective Electrokinetic Nanoparticle Treatment Of Cementitious Materials, Huayuan Zhong

Doctoral Dissertations

Various deleterious chemical species (including sulfates, chlorides, and others) contaminate concrete structures which are inherently porous and thus suffer from compromised durability. Several technologies have been developed for repairing concrete or enhancing the service life. Nevertheless, their efficiency, practicability, and cost can vary widely. Compared with chemical grout, fiber wrap, and traditional repair technology, electrokinetic nanoparticle treatment (EN) has been found to provide remarkable benefits for strength restoration and mitigation of durability problems via porosity reduction. Nanoparticle instability and over dosage issues can arise and lead to problems during treatments. In many cases, these treatment processes have been accompanied by …

Development Of A Multi-Scale Mechano-Electrochemical Battery Model, Drew J. Pereira

Theses and Dissertations

As the automotive industry moves towards large format electric vehicles, such as trucks and SUVs, the need for highly efficient, energy-dense electrodes rapidly increases. Several promising active materials have been studied and proposed, however, many of these materials undergo significant volume change upon lithiation and de-lithiation. Cell and pack designers struggle to understand and predict how active material volume change at the particle scale will affect mechano-electrochemical behavior on the electrode, cell, and pack scales. Additionally, many of these active materials suffer in their cycle life due to a mechanically-driven degradation of the electrode matrix. Therefore, the focus of this …

Development Of Predictive Equations For Thermal Conductivity Of Compost Bedding, Flávio A. Damasceno, Joseph L. Taraba, George B. Day V, Randi A. Black, Jeffrey M. Bewley, Tales J. Fernandes, Carlos E. A. Oliveira, Rafaella R. Andrade, Matteo Barbari, Patrícia F. P. Ferraz, Lorenzo Leso

Biosystems and Agricultural Engineering Faculty Publications

Among animal facilities, compost-bedded pack (CBP) barns have attracted a lot of attention from milk producers and the scientific community. Systematic investigation of the main thermal properties utilizing sawdust in CBP barns is of environmental and economic relevance. In this paper, the aim was to (a) develop predictive equations for the thermal conductivity (k) of compost bedding as a function of moisture content (MC), the degree of compaction (DC_o), and particle size (PS); and (b) investigate the links between k and depth within bedding material. Samples of compost bedding materials were collected from 42 commercial CBP …

Thermal Vacuum Chamber Modification, Testing, And Analysis, Jared C. Lehmann

Master's Theses

This work discusses the modification and analysis of the Blue Thermal Vacuum Chamber (TVAC) located at the Space Environments Lab at California Polytechnic State University, San Luis Obispo. The modified design has a cylindrical test section and can accommodate 6U Cubesats or larger for educational or research purposes. The sizing process for the modified shroud cooling system and modular heating plates is discussed. The modified cooling system uses existing nitrogen plumbing into the chamber and control systems with a new copper shroud. The modified heating system uses modular heater plates, which utilize the existing three heater strips. The modified system …

Structural Performance Of Distressed Cast-In-Place Concrete Bridge Retaining Wall, Karzan Ms Habeeb

Civil Engineering Dissertations - Archive

Cast-In-Place (CIP) concrete retaining walls have been used in the United States widely in the 20th century. CIP concrete walls have additionally proven to be structurally rigid and cost-effective for low backfill height. This type of wall is also sustainable with design service life of 75 years (TxDOT 2014). However, during service, the wall undergoes distressed movements, structural deficiency, and stability related problems. CIP cantilever concrete retaining walls often do not perform as expected, and the walls are affected by construction and/or structural deficiency, which sometimes leads to failure. The current study was inspired by distressed CIP walls located on …

Nonlinear Model Development And Validation For Ball And Plate Control System, Zachary Richter

Master's Theses

Ball and plate balancing control systems are commonly studied due to the complex dynamics associated with the instability of the system in open-loop. For simplicity, mathematical models describing the ball and plate dynamics are often linearized and the effects of complex motion are assumed to be negligible. These assumptions are rarely backed with evidence or explanations validating the simplified form of the dynamical equations of motion. This thesis focuses on developing a nonlinear model that more accurately defines the dynamics of the system, in order to quantify the error of linear and nonlinear models when compared to a Simscape physical …

Two-Dimensional Modeling Of Nonlinear Dynamics Of Forcespinning Jet Formation, Dumitru I. Caruntu, Simon Padron, Karen Lozano

Mechanical Engineering Faculty Publications

Forcespinning is a novel method that makes use of centrifugal forces to produce nanofibers rapidly and at high yields. To improve and enhance the forcespinning production method, a 2D computational forcespinning inviscid fluid dynamics model is developed. Two models, namely, time-independent and time-dependent, are obtained in order to investigate the effects of various parameters on fiber forcespinning formation (trajectory, jet diameter, tangential velocity). The fluid dynamics equations are solved using the method of multiple scales along with the finite difference method and including slender-jet theory assumptions. It is important to produce jets with small diameters in the micro- and nanorange. …

Methods Development, Design Analysis, And Testing Of Novel Centrifugal Devices For Mammalian Cell Culture Harvest, W. Aaron Dryden

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Thermo Fisher Scientific is developing a centrifugal device to be used in the biopharmaceutical industry. The novel technology was used to remove cells from cell cultures, which produce drugs and medical treatments. The harvest process of removing cells is the first step towards product purification and is an important unit operation for ensuring high product yield. Since the device is a novel technology, methods to test and evaluate the performance of the centrifuge needed to be developed.

Successful testing methods were developed in this work and were implemented on over 30 different centrifuge designs. Amongst these many designs, different operating …