Engineering Commons^™

Enhancing Ductility Of Wwr Slabs, Mohamed Shwani, Taylor J. Sorensen, Ethan Pickett, Parker Syndergaard, Marc Maguire

Faculty Publications

A series of research studies have recently identified an issue called strain localization in welded wire reinforced (WWR) members. This phenomenon reportedly concentrates strains at welded cross wire locations and severely limit ductility. Those that identified the phenomenon used it to imply that WWR is unsafe because it does not warn of failure. This research program is investigating details to mitigate the strain localization effect and demonstrate the WWR can be used safely. Sixteen beams have been constructed using WWR and rebar with various cross wire spacing, using a realistic design. The strain localization phenomenon was not demonstrated, but WWR …

Improving Sensitivity Of Electrochemical Sensors With Convective Transport In Free-Standing, Carbon Nanotube Structures, Benjamin J. Brownlee, Kevin M. Marr, Jonathan C. Claussen, Brian D. Iverson

Faculty Publications

High-aspect-ratio, porous membrane of vertically-aligned carbon nanotubes (CNTs) were developed through a templated microfabrication approach for electrochemical sensing. Nanostructured platinum (Pt) catalyst was deposited onto the CNTs with a facile, electroless deposition method, resulting in a Pt-nanowire-coated, CNT sensor (PN-CNT). Convection mass transfer enhancement was shown to improve PN-CNT sensor performance in the non-enzymatic, amperometric sensing of hydrogen peroxide (H₂O₂). In particular, convective enhancement was achieved through the use of high surface area to fluid volume structures and concentration boundary layer confinement in a channel. Stir speed and sensor orientation especially influenced the measured current in …

Gradient-Based Optimization Of Wind Farms With Different Turbine Heights, Andrew P.J. Stanley, Jared Thomas, Andrew Ning, Jennifer Annoni, Katherine Dykes, Paul Fleming

Faculty Publications

Turbine wakes reduce power production in a wind farm. Current wind farms are gen- erally built with turbines that are all the same height, but if wind farms included turbines with different tower heights, the cost of energy (COE) may be reduced. We used gradient-based optimization to demonstrate a method to optimize wind farms with varied hub heights. Our study includes a modified version of the FLORIS wake model that accommodates three-dimensional wakes integrated with a tower structural model. Our purpose was to design a process to minimize the COE of a wind farm through layout optimization and varying turbine …

Optimal Combined Long-Term Facility Design And Short-Term Operational Strategy For Chp Capacity Investments, Jose Mojica, Damon Petersen, Brigham Hansen, Kody Powell, John Hedengren

Faculty Publications

This work presents a detailed case study for the optimization of the expansion of a district energy system evaluating the investment decision timing, type of capacity expansion, and fine-scale operational modes. The study develops an optimization framework to find the investment schedule over 30 years with options of investing in traditional heating sources (boilers) or a next-generation combined heat and power (CHP) plant that provides heat and electricity. In district energy systems, the selected capacity and type of system is dependent on demand-side requirements, energy prices, and environmental costs. This work formulates capacity planning over a time horizon as a …

An Iterative Pricing Control Scheme For Renewable Integration In Residential Applications Using Inherent Thermal Energy Storage, Justin Michael Hill

All ETDs from UAB

Renewable energy continues to proliferate throughout the world as costs decrease and the public desire for clean energy rises. These sources are intermittent by nature, providing added complexity to its integration with existing grid infrastructure. This paper proposes an iterative pricing and energy consumption strategy between a utility and home energy management (HEM) system, acting on behalf of homeowners, with the goal of easing this integration while also decreasing homeowner energy costs, increasing utility profit and minimizing utility energy storage requirements. The strategy begins with a day-ahead energy cost profile developed by the utility using a mix of traditional and …

Constant Pv Output By Using Dual Converters For Dc Application, Abdullah Masoud Alghamdi

All ETDs from UAB

The energy from solar panels can be improved to extract more power by using DC-DC converters operating in continuous mode. DC-DC converters which generate fixed DC voltage were selected to observe the photovoltaic operation at maximum power point (MPP). In this thesis, a boost converter and a buck converter are cascaded to step-up then step down voltage from a photovoltaic (PV) array with changeable voltage, irradiance, and temperature, to a 24 V DC. The filtering parameters of the converter were computed and the means which is used as a switch is a metal oxide semiconductor field effect transistor (MOSFET) with …

Alpha Rhythm And The Default Mode Network: An Eeg/Fmri Study, Anthony Dean Bowman

All ETDs from UAB

Reports of the relationship between the default mode network (DMN) and alpha power are conflicting in the literature. Our goal for this study was to assess this relationship by analyzing concurrently obtained EEG/fMRI data using hypothesis-independent methods. To accomplish this, we collected fMRI and EEG data during eyes-closed rest in 20 participants aged 19-37 (10 females) and performed independent component analysis on the fMRI data and a Hamming windowed Fast Fourier Transform on the EEG data. We correlated fMRI fluctuations in the DMN with alpha power. Of the six independent components (ICs) found to have significant relationships with alpha, four …

Compression Molded E-Glass And Epoxy Resin Composites For Light Automotive Leaf Spring Application, Reyes Andres Baeza Rubio

All ETDs from UAB

Unidirectional and woven carbon or glass fibers are the most common reinforcements used in these automotive composites. To take full advantage of these materials, it is of importance to evaluate the different processes to manufacture them. The purpose of this research work is to characterize, optimize and manufacture fiber reinforced thermoset composites using the compression molding process for the application of producing improved automotive leaf springs. An epoxy resin matrix that is reinforced with E-glass fiber is the material of interest. These thermoset-based composites are evaluated to substitute the currently used steel parts in order to reduce the weight and …

Acoustic Resonance Response Of Cast Iron, Siddhartha Biswas

All ETDs from UAB

Cast iron is the most common as-cast materials used in present time. Various grades of cast iron have been developed by modifying process parameters to meet the property re-quirements. Destructive and nondestructive tests are routinely performed to maintain the integrity of the produced cast iron. Numerical and multiple linear regression models have also been developed to obtain mechanical properties from process variables such as chem-ical composition, cooling rate, liquid metal treatment. The applicability of property predic-tion models were studied by comparing predicted mechanical properties reported in pub-lished literature. Summary of the comparison is reported to guide cast iron producers to …

Low-Cost Inkjet-Printed Flexible Circuit For Gas Sensing, Sm Mehedee Parvez

All ETDs from UAB

ABSTRACT Logistics management is a major section of a stable business plan. It is responsible for planning, implementing, and controlling the production and distribution processes of the goods. Its function is even more crucial when goods, which are being handled, are perishable products like food and medicine. It is known in the food industry that a large amount of food is wasted during the transportation chain. More often than not, the main reason for foods going spoiled stems from the presence of unwanted gases around the area of storing. Accurate monitoring and controlling of the environmental conditions imposed on perishable …

Design Of An Engineering Stem Training Toolkit, Vamsi Penmetsa

All ETDs from UAB

Recent reports proclaim that more students should engage in enrolling in STEM programs at an early stage of schooling. Due to insufficient number of students pursuing in STEM programs, lot of them missing out too early in their educational career. Nine out of every ten adults had at least a high school or general education diploma, but when it comes to a higher degree only one out of every three adults held a higher degree. To overcome this problem, we need to attract more students by implementing scientific STEM projects where they can actively work on and give them a …

Smart Home Automation Using Face Recognition For Personalization And Micro-Controller For Interfacing With Devices, Mohsine Taarji

All ETDs from UAB

Face recognition is the use of technology to recognize specific facial features using camera hardware and detection software. Face recognition has been used in many fields, both industrial and personal for such tasks as security and controlling home appliances. We define a smart home as a living space that can be equipped with wireless control systems and devices, for instance, uses radio frequency or infrared communication, to automate or simplify the operation of devices. In this Thesis, we investigate the development of a system that controls appliances around the house based on particular individuals using face recognition. The system will …

Design, Testing, And Implementation Of Controls And Interface For An Adaptable Exercise Device For People With Physical Disabilities, John Hoyle

All ETDs from UAB

It has been widely noted that physical activity rates have become extremely low, while rates of sedentary life style and obesity have risen. An emerging strategy for improving healthy living has been to convert sedentary screen time into an opportunity for physical activity through active video games (AVGs). People with physical disabilities have consistently shown high incidence of physical inactivity, obesity, and other secondary conditions, and the majority of current exercise devices were not designed to accommodate those with physical disabilities. The current project worked to develop the controls and display interface for a highly adaptable exercise device for those …

Modeling Effects Of Annealing On Coal Char Reactivity To O2 And Co2, Based On Preparation Conditions, Troy Michael Holland, Sham Bhat, Peter Marcy, James Gattiker, Joel D. Kress, Thomas H. Fletcher

Faculty Publications

Oxy-fired coal combustion is a promising potential carbon capture technology. Predictive computational fluid dynamics (CFD) simulations are valuable tools in evaluating and deploying oxyfuel and other carbon capture technologies, either as retrofit technologies or for new construction. However, accurate predictive combustor simulations require physically realistic submodels with low computational requirements. A recent sensitivity analysis of a detailed char conversion model (Char Conversion Kinetics (CCK)) found thermal annealing to be an extremely sensitive submodel. In the present work, further analysis of the previous annealing model revealed significant disagreement with numerous datasets from experiments performed after that annealing model was developed. The …

Comprehensive Model Of Single Particle Pulverized Coal Combustion Extended To Oxy-Coal Conditions, Troy Michael Holland, Thomas H. Fletcher

Faculty Publications

Oxy-fired coal combustion is a promising potential carbon capture technology. Predictive CFD simulations are valuable tools in evaluating and deploying oxy-fuel and other carbon capture technologies either as retrofit technologies or for new construction. However, accurate predictive simulations require physically realistic submodels with low computational requirements. In particular, comprehensive char oxidation and gasification models have been developed that describe multiple reaction and diffusion processes. This work extends a comprehensive char conversion code (CCK), which treats surface oxidation and gasification reactions as well as processes such as film diffusion, pore diffusion, ash encapsulation, and annealing. In this work several submodels in …

Semi-Empirical Model For Fire Spread In Shrubs With Spatially-Defined Fuel Elements And Flames, Dallan Prince, Chen Shen, Thomas H. Fletcher

Faculty Publications

A semi-empirical model was developed which forms shrub geometries from distinct fuel elements (e.g. leaves) and describes flame spread from element to element. Ignition, flame growth and flame decay patterns were based on combustion data of single leaves. Extension of the model to various heating conditions was achieved by scaling the flame growth parameters using physics-based heat transfer models. The resulting model offers a novel approach to examine fire spread and to explicitly describe both distinct fuel elements and fire behavior. This approach balances computational speed and modeling detail while providing a unique perspective into fire spread phenomena. Comparisons of …

Smartphone Based Optical Spectrometer For Diffusive Reflectance Spectroscopic Measurement Of Hemoglobin, Perry Edwards, Chenji Zhang, Baigang Zhang, Xiangqian Hong, Vivek K. Nagarajan, Bing Yu, Zhiwen Liu

Biomedical Engineering Faculty Research and Publications

We report a miniature, visible to near infrared G-Fresnel spectrometer that contains a complete spectrograph system, including the detection hardware and connects with a smartphone through a microUSB port for operational control. The smartphone spectrometer is able to achieve a resolution of ~5 nm in a wavelength range from 400 nm to 1000 nm. We further developed a diffuse reflectance spectroscopy system using the smartphone spectrometer and demonstrated the capability of hemoglobin measurement. Proof of concept studies of tissue phantoms yielded a mean error of 9.2% on hemoglobin concentration measurement, comparable to that obtained with a commercial benchtop spectrometer. The …

The Pharmacodynamic Functions Of Low-Dose Rapamycin As A Model For Universal Influenza Protection, William Gust

Honors Theses

One of the most sought after breakthroughs in modern influenza research is the creation of a universal influenza vaccine that would protect against all strains of avian influenza. An unlikely model for this kind of protection might be found in the mTOR inhibitor rapamycin. Traditionally used to prevent organ transplant rejection, low doses of rapamycin have been found to protect mice against infection with distinct subtypes of influenza. However, it is not understood how a partial block in this pathway provides optimal heterosubtypic immunity. Interestingly, previous experiments have shown that low dose rapamycin inhibits germinal center formation to reduce antibody …

Lessons Learned From A 10-Year Collaboration Between Biomedical Engineering And Industrial Design Students In Capstone Design Projects, Jay R. Goldberg, Pascal Malassigné

Biomedical Engineering Faculty Research and Publications

Engineers and industrial designers have different approaches to problem solving. Both place heavy emphasis on identification of customer needs, manufacturing methods, and prototyping. Industrial designers focus on aesthetics, ergonomics, ease of use, manufacturing methods, and the user’s experience. They tend to be more visual and more concerned with the interaction between users and products. Engineers focus on functionality, performance requirements, analytical modeling, and design verification and validation. They tend to be more analytical and more concerned with the design of internal components and product performance. Engineers and industrial designers often work together on project teams in industry. Collaboration between the …

Structurofunctional Resting-State Networks Correlate With Motor Function In Chronic Stroke, Benjamin Kalinosky, Reivian B. Barillas, Brian D. Schmit

Biomedical Engineering Faculty Research and Publications

Purpose

Motor function and recovery after stroke likely rely directly on the residual anatomical connections in the brain and its resting-state functional connectivity. Both structural and functional properties of cortical networks after stroke are revealed using multimodal magnetic resonance imaging(MRI). Specifically, functional connectivity MRI (fcMRI) can extract functional networks of the brain at rest, while structural connectivity can be estimated from white matter fiber orientations measured with high angular-resolutiondiffusion imaging (HARDI). A model that marries these two techniques may be the key to understanding functional recovery after stroke. In this study, a novel set of voxel-level measures …

How A Diverse Research Ecosystem Has Generated New Rehabilitation Technologies: Review Of Nidilrr’S Rehabilitation Engineering Research Centers, David J. Reinkensmeyer, Sarah Blackstone, Cathy Bodine, John Brabyn, David Brienza, Kevin Caves, Frank Deruyter, Edmund Durfee, Stefania Fatone, Geoff Fernie, Steven Gard, Patricia Karg, Todd A. Kuiken, Gerald F. Harris, Mike Jones, Yue Li, Jordana Maisel, Michael Mccue, Michelle A. Meade, Helena Mitchell, Tracy L. Mitzner, James L. Patton, Philip S. Requejo, James H. Rimmer, Wendy A. Rogers, W. Zev Rymer, Jon A. Sanford, Lawrence Schneider, Levin Sliker, Stephen Sprigle, Aaron Steinfeld, Edward Steinfeld, Gregg Vanderheiden, Carolee Winstein, Li-Qun Zhang, Thomas Corfman

Biomedical Engineering Faculty Research and Publications

Over 50 million United States citizens (1 in 6 people in the US) have a developmental, acquired, or degenerative disability. The average US citizen can expect to live 20% of his or her life with a disability. Rehabilitation technologies play a major role in improving the quality of life for people with a disability, yet widespread and highly challenging needs remain. Within the US, a major effort aimed at the creation and evaluation of rehabilitation technology has been the Rehabilitation Engineering Research Centers (RERCs) sponsored by the National Institute on Disability, Independent Living, and Rehabilitation Research. As envisioned at their …

A Hybrid Nonlinear Vibration Energy Harvester, Wei Yang, Shahrzad Towfighian

Mechanical Engineering Faculty Scholarship

Vibration energy harvesting converts mechanical energy from ambient sources to electricity to power remote sensors. Compared to linear resonators that have poor performance away from their natural frequency, nonlinear vibration energy harvesters perform better because they use vibration energy over a broader spectrum. We present a hybrid nonlinear energy harvester that combines bi-stability with internal resonance to increase the frequency bandwidth. A two-fold increase in the frequency bandwidth can be obtained compared to a bi-stable system with fixed magnets. The harvester consists of a piezoelectric cantilever beam carrying a movable magnet facing a fixed magnet. A spring allows the magnet …

Scientific Programming Towards A Smart World, Wenbing Zhao, Xiong Luo, Huaping Liu, Kun Hua, Chaomin Luo

Electrical and Computer Engineering Faculty Publications

No abstract provided.

A Study Of Acoustic Reflections To Determine The Location, Size, Shape, And Orientation Of Reflecting Objects, Brandon M. Heller

Masters Theses

This study was conducted to examine the properties of sound in relation to echolocation, specifically in relation to its use by humans. Through my thesis, objects of varying shape and size were subjected to a sound wave to determine details about the object from the reflected sound. The shapes' comparisons were conducted at varying distances, measuring the intensity of the returning sound wave at several frequencies. The results demonstrated a correlation between the intensity of the sound in regards to distances, area of the reflector, and the shape of the reflector.

Environmental Impacts Of Selective Laser Melting: Do Printer, Powder, Or Power Dominate?, Jeremy Faludi, Martin Baumers, Ian Maskery, Richard Hague

Dartmouth Scholarship

This life cycle assessment measured environmental impacts of selective laser melting, to determine where most impacts arise: machine and supporting hardware; aluminum powder material used; or electricity used to print. Machine impacts and aluminum powder impacts were calculated by generating life cycle inventories of materials and processing; electricity use was measured by in‐line power meter; transport and disposal were also assessed. Impacts were calculated as energy use (megajoules; MJ), ReCiPe Europe Midpoint H, and ReCiPe Europe Endpoint H/A. Previous research has shown that the efficiency of additive manufacturing depends on machine operation patterns; thus, scenarios were demarcated through notation listing …

Thermal And Waveguide Optimization Of Broad Area Quantum Cascade Laser Performance, Matthew Suttinger

Electronic Theses and Dissertations

Quantum Cascade Lasers are a novel source of coherent infrared light, unique in their tunability over the mid-infrared and terahertz range of frequencies. Advances in bandgap engineering and semiconductor processing techniques in recent years have led to the development of highly efficient quantum cascade lasers capable of room temperature operation. Recent work has demonstrated power scaling with broad area quantum cascade lasers by increasing active region width beyond the standard ~10 ?m. Taking into account thermal effects caused by driving a device with electrical power, an experimentally fitted model is developed to predict the optical power output in both pulsed …

System For Metal Coated Fiber Fabrication, Da Zhang

Electronic Theses and Dissertations

For many specific applications, such as sensors, aerospace, chemical industry, deep-well oil-field industry, metal-coated fiber shows strong abilities to satisfy people's requirement. With in-line coating technology, we are able to coat Aluminum on the fibers. Using electromagnetic induction, we can easily heat an electrically conducting thing such as a metal with the eddy current. This process is defined as Induction heating. And we will melt the Aluminum by this induction heating during drawing the fibers on the tower. Introduce the fiber tower system. The drawing process of in-line technology is formed of the following steps: Position, Melting, Forming into fibers, …

Picosecond Yb-Doped Fiber Amplifier, Weibin Zhu

Electronic Theses and Dissertations

Due to its versatility, rare earth doped fiber amplifier (RDFA) has attracted a lot of researchers worldwide in recent years. Depends on different kinds of rare earth ion, RDFA can be categorized into neodymium doped fiber amplifier (NDFA), erbium doped fiber amplifier (EDFA), thulium doped fiber amplifier (TDFA), and so forth. Among many kinds of RDFA, the ytterbium doped fiber amplifier (YDFA) has received even more interest, especially in high power application, mainly because of its broad gain bandwidth and high conversion efficiency which are due to its relatively simple electronic structure. The purpose of this research is to study …

Photothermal Lensing In Mid-Infrared Materials, Justin Cook

Electronic Theses and Dissertations

A thorough understanding of laser-materials interactions is crucial when designing and building optical systems. An ideal test method would probe both the thermal and optical properties simultaneously for materials under large optical loads where detrimental thermal effects emerge. An interesting class of materials are those used for infrared wavelengths due to their wide spectral transmission windows and large optical nonlinearities. Since coherent sources spanning the mid-wave and long-wave infrared wavelength regions have only become widely available in the past decade, data regarding their thermal and optical responses is lacking in literature. Photothermal Lensing (PTL) technique is an attractive method for …

Filament Wavefront Evolution, Daniel Thul

Electronic Theses and Dissertations

Filamentation is a complex process that gives rise to many nonlinear interactions. However, the fundamentals of filament formation and propagation can be explained in terms of two dominant mechanisms: Kerr self-focusing and plasma defocusing. The first to occur, self-focusing, is responsible for an increase in irradiance through beam collapse. This process requires sufficient initial peak power, on the order of gigawatts for near infrared beams in air. Plasma defocusing then arrests the collapse process once the irradiance reaches the ionization threshold of the medium. These two processes balance each other in an extended plasma channel known as a filament. A …