Engineering Commons^™

Modeling And Simulation Of The Thermoforming Process In Thermoplastic-Matrix Composite Materials, Philip M. Bean

Electronic Theses and Dissertations

Thermoplastic-matrix composite materials have unique advantages over traditional thermosets including faster processing, improved fracture toughness, and recyclability. These and other benefits have caused increasing interest in the use of these materials in both aerospace and automotive industries. Due to the differences in behavior, these materials require a different type of manufacturing process to thermoset matrix composites. This manufacturing process generally involves using pre manufactured tape-layers. These layers, containing both thermoplastic-matrix and fiber-reinforcement, are aligned to the desired orientation, and stacked up into a “tailored blank” using an automated tape layup machine. They are then heated to the thermoplastic melting temperature …

Experimentation And Modeling Of The Effects Of Along-Wind Dispersion On Cloud Characteristics Of Finite-Duration Contaminant Releases In The Atmosphere, Jessica M. Morris

Graduate Theses and Dissertations

Along-wind dispersion, or stretching of the cloud in the direction of the wind, plays an important role in the concentration and modeling of contaminant releases in the atmosphere. Theoretical and empirical derivations were compared for appropriate parameterization of along-wind dispersion. Available field data were analyzed to evaluate and improve previous parameterizations of the along-wind dispersion coefficient, σ_x. An experimental test program was developed and executed in an ultra-low speed wind tunnel at the Chemical Hazards Research Center to determine the effects of the time distribution coefficient on true finite-duration releases from an original area source. Multiple wind speeds, release durations, …

The Restoration Of The Nile River And Its Delta, Egypt. Numerical Modeling, Basim Mohammed Naseef Al-Zaidi

Theses and Dissertations

The construction of the High Aswan Dam significantly reduced the flood flows and the sediment supply to the Egyptian portion of the Nile River. Consequences of this changes in river hydrology are diffuse channel bed erosion in the upstream part of the river, in- channel sedimentation in the downstream part of the system, delta recession, habitat deterioration, wetlands loss, water pollution, and environmental problems. The feasibility of a Nile River-Delta restoration project with controlled flow releases and sediment augmentations at Aswan is here investigated with the aid of site-specific one-dimensional morphodynamic models. The water source for the restoration project, based …

Modeling And Simulation Of Damage In The Brazilian Indirect Tension Test Using The Finite-Discrete Element Method, Jeremiah C. Leyba

Civil Engineering ETDs

The Brazilian indirect tension test is used to investigate possible correlations between progressive damage and associated permeability changes. The test offers ease of replicability with a damage behavior known to lead to fracture openings as a tool for interpreting the indirect tensile strength of concrete and rocks. This behavior can lend insight into the nature of tensile damage and fracture progression in association with changes in permeability. The nature of these brittle materials is known to exhibit rapid failures in the Brazilian indirect tension test and require a method to retard the progression of damage for the possibility of acquiring …

A Perceptual Comparison Of “Black Box” Modeling Algorithms For Nonlinear Audio Systems, Paul G. Mayo

Audio Engineering Theses

Nonlinear systems identification is a widespread topic of interest, particularly within the audio industry, as these techniques are employed to synthesize black box models of nonlinear audio effects. Given the myriad approaches to black box modeling, questions arise as to whether an “optimal” approach exists, or one that achieves valid subjective results as a model with minimal computational expense. This thesis uses ABX listening tests to compare black box models of three hardware audio effects using two popular nonlinear implementations, along with two proposed modified implementations. Models were constructed in the Hammerstein form using sine sweeps and a novel measurement …

Modelling The Financial Effects Of Naïve Neutral Zone Limits On Energy Storage Systems Participating In Midwest Iso Energy Markets Under Frequency Regulation Prioritization Policies, Patrick J. Mccarthy

Masters Theses

Battery Energy Storage Systems (BESS) participating in frequency regulation services in MISO (Midcontinent Independent System Operator) energy markets do so by charging from and discharging to the bulk electrical grid to satisfy power demands. Frequency regulation can demand a high energy throughput from a BESS, causing electrochemical aging. The aging of a BESS must be controlled to within financially feasible limits. MISO has proposed new frequency regulation prioritization policies that enable a BESS to manage its own aging by setting its acceptable State of Charge (SOC) range, called its neutral zone. MISO will seek to prioritize a BESS’ regulation so …

Control-Oriented Automatic Transmission- Based Powertrain Modeling And Simulation With Judder, Harshal B. Kundale

Masters Theses

This work presents automatic transmission-based powertrain modeling. The powertrain consists of an engine, torque converter with lock up clutch, transmission gearbox, propeller shaft, and vehicle body. Simplified powertrain component models are developed for vehicle powertrain dynamic response analysis and future control work. The powertrain components are modeled with algebraic and first order non-linear differential equations. A MATLAB-based powertrain simulation system is developed to investigate the transient characteristics during lock up of torque converter. Simulation results are used in the determination of effects of judder on torque and angular velocity. Clutch judder is a self-excited vibration that occurs during the clutch …

Smart Technologies For Oil Production With Rod Pumping, Brigham Wheeler Hansen

Theses and Dissertations

This work enables accelerated fluid recovery in oil and gas reservoirs by automatically controlling fluid height and bottomhole pressure in wells. Several literature studies show significant increase in recovered oil by determining a target bottomhole pressure but rarely consider how to control to that value. This work enables those benefits by maintaining bottomhole pressure or fluid height. Moving Horizon Estimation (MHE) determines uncertain well parameters using only common surface measurements. A Model Predictive Controller (MPC) adjusts the stroking speed of a sucker rod pump to maintain fluid height. Pump boundary conditions are simulated with Mathematical Programs with Complementarity Constraints (MPCCs) …

Testing And Packaging For Mems Acoustic Emission Sensors, Ting-Hung Liu

USF Tampa Graduate Theses and Dissertations

The goal of this research is to improve the structure and dimension of the MEMS acoustic emission sensor. Acoustic emission sensor (AE sensor) based on the piezoelectric transducer is a well-developed technology in non-destructive testing that is widely used to determine permanent damage such as cracks and corrosions in buildings and structures. The AE sensor can be used to monitor cracks in structures and to check leakage in pressurized systems. The location of cracks in a structure or system leakage causes a high-frequency surface vibration while releasing ultrasonic energy. The frequency of this energy is typically between 30 kHz to …

The Design, Modeling, And Optimization Of A Biomimetic Soft Robot For Fluid Pumping And Thrust Generation Using Electroactive Polymer Actuators, Zakai Jedidiah Olsen

UNLV Theses, Dissertations, Professional Papers, and Capstones

Nature is a constant source of inspiration for engineers and scientists through its simple, effective, and elegant solutions to many complex problems. Smart materials and soft robotics have been seen to be particularly well suited for developing biomimetic devices and are active fields of research. In this study, the design, modeling, and optimization of a new biomimetic soft robot is described. Preliminary work was made in the modeling of a biomimetic robot based on the locomotion and kinematics of jellyfish. Modifications were made to the governing equations for jellyfish locomotion that accounted for geometric differences between biology and the robotic …

Reduced Order Modeling For Virtual Building Commissioning, Sean Rosin

Boise State University Theses and Dissertations

Model order reduction can help reduce the time and monetary constraints associated with building commissioning and significantly decrease overall building energy consumption through virtual commissioning. This research aimed to determine the effectiveness of using reduced order models to simulate the overall building energy consumption, and to estimate the energy savings from control-based commissioning recommendations.

A case study building was modeled using a ‘Lumped RC’ thermal model with three thermal resistances and capacitances (3R3C) for the building interior and a 2R1C model describing the building foundation. Due to energy consumption being dependent on building systems, this model was coupled with a …

Dispensing Medical Countermeasures In Public Health Emergencies Via Home Health Agencies And Points Of Distribution, Anna Hudgeons

Industrial Engineering Undergraduate Honors Theses

A major concern regarding emergency preparedness on the state government level involves the handling and dispensing of the Strategic National Stockpile (SNS) of medicinal supplies. Each state is required to update and maintain a plan of action for dispensing SNS materials that would effectively provide care to the state’s population in times of distress. This research evaluates a state’s ability to dispense an adequate amount of medicine to her population in a timely manner, specifically after it has been received by the state government. Although simulation modeling has previously been utilized to replicate the dispensing process at pre-designated points of …

Resampling Methods And Visualization Tools For Computer Performance Comparisons In The Presence Of Performance Variation, Samuel Oridge Irving

LSU Master's Theses

Performance variability, stemming from non-deterministic hardware and software behaviors or deterministic behaviors such as measurement bias, is a well-known phenomenon of computer systems which increases the difficulty of comparing computer performance metrics and is slated to become even more of a concern as interest in Big Data Analytics increases. Conventional methods use various measures (such as geometric mean) to quantify the performance of different benchmarks to compare computers without considering this variability which may lead to wrong conclusions. In this paper, we propose three resampling methods for performance evaluation and comparison: a randomization test for a general performance comparison between …

Assured Android Execution Environments, Brandon P. Froberg

Theses and Dissertations

Current cybersecurity best practices, techniques, tactics and procedures are insufficient to ensure the protection of Android systems. Software tools leveraging formal methods use mathematical means to assure both a design and implementation for a system and these methods can be used to provide security assurances. The goal of this research is to determine methods of assuring isolation when executing Android software in a contained environment. Specifically, this research demonstrates security properties relevant to Android software containers can be formally captured and validated, and that an implementation can be formally verified to satisfy a corresponding specification. A three-stage methodology called "The …

A Framework For Assessing Water Quality, Prioritizing Recovery Potential, And Analyzing Placement Of Best Management Practices, Tadesse Animaw Sinshaw

Electronic Theses and Dissertations

Motivated by the U.S. EPA goals, this research developed a framework to support identification and restoration of nutrient-impaired water bodies. The study objectives were developing total nitrogen (TN) and total phosphorus (TP) prediction models, evaluating the impact of social indicators on assessing recovery potential, and developing a spatial decision support system for choice and placement of best management practices (BMPS). An artificial neural network was used to develop TN and TP predictive regional models for U.S. lakes using easily measurable and cost-effective variables. The performance of models was superior for regions trained with larger datasets and/or regions with lower temperature …

Physical Modeling Of Lithium-Ion Aging For Automotive Applications, Anurag Kamal

Dissertations, Master's Theses and Master's Reports

This thesis extends the full-scale electrochemical model for a Lithium-ion battery based on the porous electrode theory to incorporate aging mechanisms of solid electrolyte interface formation, cyclic electrode degradation, and lithium plating during overcharge, automotive vibrations, mechanical stress, and cell temperature, as reported in the existing literature. Further, the thesis presents the scope of the parameters used in the model to enable designers to extend the equations for new mechanisms and variability of other parameters.

An increased set of equations makes the complexity of the model even higher, and it would be very computationally complex to simulate this model. This …

Modeling Crevice Corrosion Of Nickel Alloy 625 In Seawater, Linsey Grzeschik

Williams Honors College, Honors Research Projects

In this work, COMSOL Multiphysics was used to model crevice corrosion of Nickel Alloy 625 in seawater. Initial model parameters included a bulk solution of 0.6M (Cl^-) ASTM D1141-98 artificial seawater, a crevice length of 12.7mm, and applied current of 0.44V_SHE. A crevice gap of 7μm and 10μm were compared using a 3.0m polarization curve of the simulated critical crevice solution for Alloy 625. A constant crevice gap of 10μm was used to compare varying polarization curves of 3.0m, 3.5m, and deaerated seawater. The model found a variation in free chloride concentration from the bulk to …

Reaction Kinetics Of The Hydrogenation Of Phenol In A Tubular Reactor, Michael Selzer

Williams Honors College, Honors Research Projects

The reaction kinetic parameters for the hydrogenation of phenol to cyclohexanone are determined for the liquid phase reaction with the palladium catalyst supported on an electrospun PVDF membrane. Runs of the reactor were completed at catalyst loadings of 40, 50, and 60 g/m², and tube diameters of 0.187 in and 0.25 in with a runtime of ten hours. One-dimensional and two-dimensional models of the experimental setup were developed. Fitting data to the one-dimensional model found that the pre-exponential factor was 2.50 x 10⁴, the activation energy was 7.69 kJ/mol, and the order with respect to phenol …

Development Of Novel Models To Study Deep Brain Effects Of Cortical Transcranial Magnetic Stimulation, Farheen Syeda

Theses and Dissertations

Neurological disorders require varying types and degrees of treatments depending on the symptoms and underlying causes of the disease. Patients suffering from medication-refractory symptoms often undergo further treatment in the form of brain stimulation, e.g. electroconvulsive therapy (ECT), transcranial direct current stimulation (tDCS), deep brain stimulation (DBS), or transcranial magnetic stimulation (TMS). These treatments are popular and have been shown to relieve various symptoms for patients with neurological conditions. However, the underlying effects of the stimulation, and subsequently the causes of symptom-relief, are not very well understood. In particular, TMS is a non-invasive brain stimulation therapy which uses time-varying magnetic …

Characterization And Mechanical Evaluation Of Discontinuous Carbon Fiber Based Liquid Molded Nylon-6 Composites, Siddhartha Brahma

All ETDs from UAB

The Anionic Ring Opening Polymerization (AROP) of caprolactam to form polyamide-6 (PA6) or liquid molding for polyamide-6 (LMPA6) presents the opportunity for a new class of composite materials with excellent performance and wide applicability from automotive, energy, transportation, and aerospace. Despite the inherent advantages with the process, industrial adoption is virtually nonexistent. Additionally, the growing trend of reclaiming fibers can also be coupled with this process with relative ease. The following work will evaluate the liquid molding process, particularly for the use of recycled or reclaimed carbon fibers, in the following ways. First, the adaptability of the process to use …

Modeling And Analysis Of Iot Systems Using Shannon's Channel Model, Anthony G. Winchester

All ETDs from UAB

The Internet of Things (IoT) is a ubiquitous technology that can mark the evolution of modern world. Since the internet has become a common household resource like the land line was in the past, it is time to take technology to the next level. With the manipulation of signals, we now have the use of wireless devices that are connected to various devices (both wireless and wired). The idea is to not only engineer devices that connect to the web, but also make them smart using processors embedded in devices coupled with internet to provide an intelligent system. Our research …

Effect Of Poisson’S Ratio On Young's Modulus Characterization Using Ultrasonic Technique By Modeling, Michael Onyetube

Electronic Theses and Dissertations

The past 27 years has witnessed a revolutionary growth in the progress of material development and application in almost all industry and business sectors, and this seems to be continuing even today. So many material-driven innovations have enabled the global spread in technology and improvements in capability, ranging from communications to aerospace and healthcare, to automotive and agriculture. Mechanical behavior of elastic materials is modeled by two main independent constants; Young’s modulus and Poisson’s ratio. An accurate measurement of both constants is necessary in most engineering applications, for example, the standard materials used for the calibration of some equipment, quality …

Quantifying Non-Recurrent Delay Using Probe-Vehicle Data, Jacob Douglas Keaton Brashear

Theses and Dissertations--Civil Engineering

Current practices based on estimated volume and basic queuing theory to calculate delay resulting from non-recurrent congestion do not account for the day-to-day fluctuations in traffic. In an attempt to address this issue, probe GPS data are used to develop impact zone boundaries and calculate Vehicle Hours of Delay (VHD) for incidents stored in the Traffic Response and Incident Management Assisting the River City (TRIMARC) incident log in Louisville, KY. Multiple linear regression along with stepwise selection is used to generate models for the maximum queue length, the average queue length, and VHD to explore the factors that explain the …