Mechanical Engineering Commons^™

Studies On Powder Compaction And Wire Extrusion Of Pure Metals And Metal/Cnt Nano Composites, Qiang Zhou

Electronic Theses and Dissertations, 2020-2023

The goal of this dissertation is to fabricate wires made of Cu/CNT and Al/CNT composites with good mechanical strength and super thermal/electrical conductivities using powder compaction and wire extrusion manufacturing processes. Powder compaction was studied using both test and simulation. Cold compaction, hot compaction and vibration assisted (cold) compaction tests were conducted to achieve different density ratios. Hot compaction tests improved about 6% compared with cold compaction under the same compression pressure. Although the relative density ratio does not obviously improve at vibration assisted (cold) compaction, the strength of the specimens made under vibration loading is much better than those …

An Evaporation Based Micro-Synthetic Jet In Microchannel And Its Applications, Ehsan Sourtiji

Electronic Theses and Dissertations, 2020-2023

An approach to create synthetic jets at micro-scales using periodic bubble growth and collapse was presented and studied over a range of operating frequencies (0.1 to 2.5 Hz) and heating powers (3 to 4.5 Watt). The microfluidic device uses an interfacial layer between vapor and liquid phases which substitutes the requirement for a physical flexible membrane and any other moving parts. The bubble explosion and implosion in the chamber was triggered by periodically powering a micro-heater, which in turn generated the synthetic jet. High-speed camera photography and a microscope were used to capture sequential images of bubble nucleation, growth and …

Mid-Infrared Laser Absorption Spectroscopy And Ignition Delay Time Measurements Of Advanced Renewable Fuels At High Pressure In A Shock Tube, Erik Ninnemann

Electronic Theses and Dissertations, 2020-2023

The United States government has set 2050 as the target for net-zero greenhouse gas emissions due to their increasing levels and the subsequent rise in global temperatures. To meet this target, there has been renewed interest in the combustion of high-energy biofuels that could combat these issues. Thus, the Department of Energy started the Co-Optimization of Fuels and Engines program to find bioderived blendstocks that can harmonize with current and future generation engines to increase power and efficiency, all while reducing overall emissions. As part of this program, it is crucial to understand the combustion of these fuels at the …

Understanding Forearm Muscle Coordination In Children, Miguel Gonzalez

Electronic Theses and Dissertations, 2020-2023

A combination of surface electromyography (EMG) and pattern recognition algorithms have led to improvements in the functionality of upper limb prosthetics. This method of control relies on user's ability to repeatedly generate consistent muscle contractions. Research in EMG based control of prosthesis has mainly utilized adult subjects who have fully developed neuromuscular control. Little is known about children's ability to generate consistent EMG signals necessary to control artificial limbs with multiple degrees of freedom. To address this gap, two experiments were designed to validate and benchmark an experimental protocol that quantifies the ability to coordinate forearm muscle contractions in able-bodied …

Florida Building Code, Energy Conservation, 7th Edition (2020) Vs. 2018 International Energy Conservation Code Residential Stringency Analysis, Florida Solar Energy Center, Jeffrey Sonne

FSEC Energy Research Center®

This report summarizes the review and evaluation activities carried out to make a determination whether the residential provisions of the 7th Edition (2020) Florida Building Code, Energy Conservation meet or exceed those of the 2018 International Energy Conservation Code (IECC) code.

Market Driven Residential Energy Codes: Comparing Performance In A Changing Technical Environment, Code Official Survey Results, Florida Solar Energy Center, Karen Fenaughty

FSEC Energy Research Center®

The DOE Code Survey conducted for this project was launched on 2/18/2020 and closed 3/20/2020. There were 907 participants responding to at least some portion of the 48 question survey, though some questions received poor attention. Note that the number of responses to each question varies by design and depends on answers to prior questions. Further, multiple answers are sometimes allowed.

Fsec Energy Research Center Highlights 2020, Brochure, Florida Solar Energy Center, Sherri Shields

FSEC Energy Research Center®

This 5-page "brochure" provides an overview of capabilities at the FSEC Energy Research Center. As Florida's statewide energy research center, FSEC has a 45-year history of basic and applied research excellence, which has grown in scope to include all aspects of renewable energy, energy storage, electric vehicles, and energy efficiency technologies. FSEC's education and outreach programs have trained thousands of energy practitioners and informed energy consumers. This document was originally created to inform City of Cocoa Council members about FSEC during their external visit to the Center in June 2020, during COVID-19. FSEC Art#: PIO-104

Mimicking Blood Rheology For More Accurate Modeling In Benchtop Research, Lindsey Webb

The Pegasus Review: UCF Undergraduate Research Journal

Because blood is challenging to use as a working fluid in a laboratory setting due to health and safety concerns, a blood analogue would be useful to perform benchtop experiments. Viscosity is an important fluid property for modeling and experiments, especially because blood is a shear thinning fluid; therefore, it has a decreasing viscosity with higher shear rates. This project seeks to create a blood-mimicking fluid for benchtop laboratory use. Numerous fluids with different combinations of water, glycerin, salt, and xanthan gum (XG) were created to mimic blood viscosity at different hematocrit levels. Four additional solutions were also created from …

Measured Cooling Energy Savings From Reflective Wall Finishes: Evaluation As An Efficiency Measure Across Climates, Florida Solar Energy Center, Danny Parker

FSEC Energy Research Center®

In past research, reflective roofs have shown significant potential to reduce cooling in buildings. However, there have been few empirical evaluations of cooling reductions from changing wall reflectance. In the reported study, several experiments with instrumented scale test buildings are used to provide validation for a detailed simulation analysis across varied North American climates. The simulations establish the potential of reflective walls as an efficiency measure in existing buildings against climate.

This paper was published in the 2020 ACEEE Summer Study on Energy Efficiency in Buildings.

Who's Leading: The Dance Between Mini-Splits And Existing Hvac Systems, Florida Solar Energy Center, Cheryn Metzger

FSEC Energy Research Center®

Recently, many utilities across the U.S. have provided incentives for ductless mini-split heat pumps due to their relatively high efficiencies. However, when these ductless mini-splits are installed in existing homes, utilities and researchers find that they are not living up to their energy saving potential, due to a lack of coordinated controls with the existing HVAC system. The Pacific Northwest National Laboratory (PNNL), the Florida Solar Energy Center (FSEC), and The Levy Partnership are all leading projects across the country to address this problem. The goal for this body of work is to determine which control strategies provide the most …

Targeting The Best Performing Home Efficiency Programs With Advanced Metering Evaluation Supplemented By Simulation, Florida Solar Energy Center, Robin Vieira

FSEC Energy Research Center®

The authors investigated the impacts of seven residential rebate energy efficiency programs offered by a municipal utility. The evaluation examined energy use pre and post retrofit using the Advanced Metering Infrastructure (AMI) data, disaggregated by major end-use and weather-adjusted; and also by detailed simulations. Residences modeled were representative of typical participants for that measure based on factors such as year built, conditioned square feet and number of bedrooms.

Our analysis found the residential rebate programs to be of highly varied effectiveness, but important differences surfaced between the simulation and the AMI data evaluation. Not surprisingly, programs with larger samples tended …

Analysis Techniques For Evaluating Energy Conservation Programs Using Utility Ami Data, Florida Solar Energy Center, Richard Raustad

FSEC Energy Research Center®

With the evolution of Advanced Metering Infrastructure (AMI) electric meters, utility companies now have direct access to whole building electricity use at a granular time scale. AMI data can be used for a variety of purposes beyond billing, for example, to evaluate the efficacy of energy conservation (EC) programs. Historical methods for calculating EC program savings include building simulation models and laboratory and/or field testing. With big data now available, which analysis methods are more likely to yield quality results?

In a recent project, the Orlando Utility Commission provided monitored AMI data from Oct 1, 2015 - Sep 27, 2018 …

Improving Energy Savings And Peak Demand Reduction Estimates Using Ami Data For Utility Commercial Rebate Programs, Florida Solar Energy Center, Karen Fenaughty

FSEC Energy Research Center®

Solar reflective, or cool roofs, are a demonstrated method of reducing air conditioning energy, particularly in cooling-dominated climates. Similarly, efficient lighting or mechanical equipment replacement programs have a reputation for achieving large savings in c01mnercial buildings. Savings estimates for such measures have historically used monthly utility bills, which only provide a macroscopic view of utility program savings. Advanced Metering Infrastructure (AMI) is commonly used in the U.S. by utilities for residential and commercial customers and provides not only a valuable record of changing premise energy use and demand profiles but in much greater detail than utility bills, if desired.

Partnering …

Characterization Of Mechanical Ventilation Systems In New Us Homes: What Types Of Systems Are Out There And Are They Functioning As Intended?, Florida Solar Energy Center, Eric Martin

FSEC Energy Research Center®

As the airtightness of homes improves to meet energy efficiency goals, it becomes more important for mechanical ventilation systems to help maintain a comfortable and healthy indoor air environment. ASHRAE Standard 62.2 provides national guidance for mechanical ventilation system design and installation, however adoption of those guidelines into local building codes has occurred at different rates. Once provisions for mechanical ventilation are adopted in a local code, are mechanical ventilation systems properly designed, installed, commissioned and operated according to code or above-code program requirements? This paper presents results from field studies that include characterization of whole house mechanical ventilation (WHMV) …

Measured Energy And Moisture Performance Impacts From Vented And Unvented Attic With Insulation On Top Of Ceiling In The Hot Humid Climate Zone, Florida Solar Energy Center, Charles Withers, Jr.

FSEC Energy Research Center®

Sealing attic vents helps decrease house air leakage and may reduce some moisture issues in attics in hot humid climates. new code-approved unvented attics can use different types of insulation materials, however, there are specific requirements that vary by materials used and climate zone. These requirements may be complex and may increase construction and operational energy costs.

This paper was published in the 2020 ACEEE Summer Study on Energy Efficiency in Buildings.

Fsec Energy Research Center Strategic Plan (2020-2025) Executive Summary, Florida Solar Energy Center, James Fenton

FSEC Energy Research Center®

The Florida Legislature created the Florida Solar Energy Center (FSEC) in 1975 to support the growth and development of renewable energy. The year 2025 will mark the half-century mark for FSEC's service as the statewide energy research and education institute. In preparation for the next 50 years of dynamic energy developments, the FSEC Energy Research Center is undertaking a strategic planning and rebranding process.

Side-By-Side Testing Of Solaire Solar Ac, Florida Solar Energy Center, John Sherwin

FSEC Energy Research Center®

The FSEC Energy Research Center performed a series of side-by-side tests to compare a heat pump system with a SolAire thermal collector against one without. The tests were performed in three phases: 1) baseline operation, 2) heat pump system operating with SolAire collector using collector manufacturer's wiring specifications, and 3) heat pump system operating with SolAire collector using Daiken/OEM wiring specifications. Each phase represented 5 full days of continuous operation during August of 2018 in Cocoa, Florida. Phase 1 baseline testing demonstrated that the two Daiken heat pump systems and test houses performed similarly and there were no differences between …

Assessing 3d Printability Of Bioinks, Nicole Ramirez

Honors Undergraduate Theses

The field of tissue engineering (TE) is continuously improving through the use of additive manufacturing techniques (AM) such as three-dimensional (3D) bioprinting. The 3D bioprinter has significantly gained attention in the TE field because it is more efficient than regenerative medicine and is readily available as opposed to organ transplants. Working like a conventional 3D printer, the 3D bioprinter is able to dispense material layer by layer from the bottom up with the printing head able to move in the X, Y, and Z direction. This movement allows for the fabrication of structures with complex geometries. In this study, the …

Cell Encapsulation In Microfluidic Channels, Mohammad Nooranidoost

Electronic Theses and Dissertations, 2020-2023

Droplet Microfluidics can be utilized to control the production of single droplets and double emulsions in biomedical application. This dissertation analyzes the droplet formation in hydrophobic and hydrophilic microchannels, encapsulation of cells in flow-focusing channels, and deformation of cell-laden droplets in constricted microcapillaries. The formation of droplets is studied in hydrophobic and hydrophilic channels in order to investigate the role of contact angle on flow structures and droplet generation patterns. In the hydrophobic case, stable and well-structured droplet and slug generation is achieved. However, the flow structure in the hydrophilic case significantly depends on contact angles of the walls. A …

Classical Engineering Systems Provide Behavioral Analog For Ephemeral Insect And Plant Biomechanics, Nicholas Smith

Electronic Theses and Dissertations, 2020-2023

In this dissertation we consider ephemeral behaviors of two small-scale living systems, mosquitoes and citrus fruit reservoirs. While these two systems share few obvious commonalities, they both express life events that are complex and conclude within approximately 50 milliseconds. We utilize high-speed videography, between 1,000-16,000 fps, to detail how complex behavior can be modeled as classical engineering systems. Beginning with the larger organism we assessed the landing and takeoff behavior of Aedes aegypti mosquitoes to ascertain the secrets of their covert interaction with humans. At takeoff, mosquitoes decrease pushing contact time with substrates of low friction through a modified takeoff …

A Computational Biomechanical Model-Based Optimization Of Fulcrum Support In Orthosis Enabled Closed Reduction Of Developmental Dysplasia Of The Hip, Christopher Rose

Electronic Theses and Dissertations, 2020-2023

Hip abduction orthosis devices (HAOD) are used to reduce the hip joint of infants affected by developmental dysplasia of the hip (DDH). HAOD have been successful for mild cases of DDH and ineffective for severe cases. Efforts in understanding the biomechanics of lower limbs have been made to improve the success rate of current treatment methods, especially for Grade IV dislocations (G4). The aim of this dissertation is twofold: first, it proposes the use of a varying fulcrum point (FP) located below the leg to improve DDH treatment; and secondly, it defines the optimal FP (OP) location for a broad …

Study On Ductile Fracture With Anisotropic And Strain Rate Effects In Manufacturing Processes, Hao Pan

Electronic Theses and Dissertations, 2020-2023

Ductile fracture is a topic of great importance in automotive and aerospace industries. Prediction of ductile fracture in engineering structures relies on developing robust material models under complex loading conditions. This dissertation addresses the anisotropic and strain rate effects in constitutive and ductile fracture models of lightweight metals. In the present modeling framework, the anisotropic plasticity behavior is modeled by combination of an initial anisotropic yield function and an isotropic hardening correction by Lode dependence. A new all-strain based anisotropic fracture model is proposed based on the approach of linear transformation on plastic strain rate tensor. The strain rate effects …

Multi-Species Measurements At High Temperatures Using Advanced Mid-Infrared Laser Schemes, Zachary Loparo

Electronic Theses and Dissertations, 2020-2023

High-temperature reacting systems are central to many fields including propulsion, power generation, and transportation. Studying such systems requires the use of experimental facilities such as shock tubes to obtain the relevant high temperature conditions, and non-intrusive diagnostic tools for monitoring parameters of interest in the reaction zone, including temperature and species concentration time-histories. Laser absorption spectroscopy offers high-speed, in-situ measurements of the reacting flow field and provides direct measurements of species concentrations and temperature. Applying absorption spectroscopy via different diagnostic strategies enables tailored measurements of these parameters across a variety of combustion systems for chemical kinetic model refinement and enhancing …

Interfacial Properties Modulate Water Entry Dynamics For Spherical Projectiles, Daren Watson

Electronic Theses and Dissertations, 2020-2023

Rigid bodies impacting liquid pools incite splashing and air-entraining cavities that depend on impactor shape, entry speed, surface texture, and free surface conditions. In this body of work, we investigate the influence of interfacial properties on water entry dynamics for free-falling spherical projectiles. Our investigations translate to everyday fluid-structure interactions that are complex and generally conclude beyond the temporal acuity of the naked eye. High-speed videography between 1000 -- 3200 fps is used to digitize the water entry process and measure salient splash features under different initial conditions. We assess splashes arising from the impacts of free-falling hydrophilic spheres with …

Pathological Tremor As A Mechanical System: Modeling And Control Of Artificial Muscle-Based Tremor Suppression, Christopher Kelley

Electronic Theses and Dissertations, 2020-2023

Central nervous system disorders produce the undesired, approximately rhythmic movement of body parts known as pathological tremor. This undesired motion inhibits the patient's ability to perform tasks of daily living and participate in society. Typical treatments are medications and deep brain stimulation surgery, both of which include risks, side effects, and varying efficacy. Since the pathophysiology of tremor is not well understood, empirical investigation drives tremor treatment development. This dissertation explores tremor from a mechanical systems perspective to work towards theory-driven treatment design. The primary negative outcome of pathological tremor is the undesired movement of body parts: mechanically suppressing this …

Heat Transfer And Correlations Of Jet Array Impingement With Flat And Pimple-Dimpled Plate, Husam Nizar Ahmad Zawati

Electronic Theses and Dissertations, 2020-2023

This study compares and analyses the heat transfer between a novel jet array impingement configuration (designated as NPR) and a baseline jet orifice plate (flat) in a maximum crossflow scheme. Both jet plates feature inline arrays of 20 x 26 circular air jets that orthogonally impinge on a flat target surface consisting of 20 segments, parallel to the jet plates. The NPR plate consists of staggered semi-spherical pimples (protrusions) and dimples (imprints) with a jet-to-pimple diameter ratio (Dj,p/Dp) of 0.07 and jet length-to-pimple diameter ratio (L/Dj,p) of ~ 1 with a protrusion ratio (tp/Dj,p) of 2.78. The dimples (imprints) have …

Molecular Dynamics Simulation Study On Thermal Conduction Of Cnt-Cu/Al Composites With New Meam Potentials Between C And Cu/Al, Luyang Ren

Electronic Theses and Dissertations, 2020-2023

Carbon nanotubes (CNTs) have been a promising material for thermal management applications including micro/nano-electromechanical system (MEMS/NEMS) due to their extremely high thermal conductivity values. CNTs-reinforced Cu/Al (CNT-Cu/Al) composites are attractive to meet all-around requirements on high thermal performance materials to be applied in many areas, such as aerospace, automotive and electronic packaging. However, the experimental results on resultant thermal conductivity of these composites are far from expectation due to the law of mixture. In this research, molecular dynamics (MD) simulation is used to study the thermal conduction of CNT-Cu/Al composites. Before the simulation is conducted, new inter-atomic potentials for the …

Production And Elastomer Compatibility Of Renewable Fuels, Alan Felix

Electronic Theses and Dissertations, 2020-2023

Hydrocarbon fuel plays an essential role in modern day society and significant research effort is put forth for fuel characterization, performance optimization, and new procedures for synthesis. Despite the eventual and inevitable shift away from hydrocarbon fossil fuels to more renewable energies, investigations into liquid hydrocarbons remain useful while governments slowly adopt and integrate alternative energies. Many hydrocarbon fuel alternatives can potentially bridge the gap between today's heavy reliance on fossil fuels and future complete adaptation of clean energy. One such alternative is biofuel, which is still hydrocarbon based but is made from bio-materials, most notably plants. Widespread use of …

Experimental, Analytical And Computational Analyses Of Linear And Radial Shape Memory Alloy Helical Actuators, Ryan Puchaty

Electronic Theses and Dissertations, 2020-2023

As access to Shape Memory Alloys (SMAs) has expanded beyond their use as linear wires, the need for characterizing more complex forms that account for the effects of multi-axial stress, strain, and displacement has become increasingly important in actuator design. The novel uses of SMA actuators have also moved the devices into previously unexplored loading conditions, where established theory does not adequately model the real behavior. This work seeks to alleviate some of these issues by addressing problems with the most common multi-axial stress devices: helical springs. New applications are requiring high forces in small spaces, where SMAs' high work …

Design Of An Annular Disc-Shaped Heat Pipe For Air-Cooled Steam Condensers, Ahmad Saleh

Electronic Theses and Dissertations, 2020-2023

Limitations on water utilization are turning into an expanding issue for the power and electricity generation industry. As a contribution to the solution of water consumption problems, utility companies are shifting toward using air-cooled condensers (ACC) in replace to the typical water-cooling methods of once-through cooling and the surface condenser/wet-cooling tower combination. Although the ACC is a dry cooling method, the industry is quite hesitant to switch over to ACC mainly for three reasons: (a) lower power output, (b) higher capital cost, and (c) larger physical footprint. All these drawbacks are because of the high overall thermal resistance of condensing …