Innovative Engineering with Renewable Resources

Our REU site, Innovative Engineering using Renewable Resources, features multi-disciplinary problems that exploit interesting properties of bamboo. Bamboo is a renewable resource and has garnered attention in Alabama as an agricultural crop that can play an important part in numerous engineering applications. Project supervisors are faculty members from engineering and computer science with experience in mentoring students. The proposed REU program includes professional development opportunities that focus on both preparation in conducting research and learning how to advance discovery for commercial purposes. During the nine-week summer research experience, we will introduce students to a variety of experimental and analytical tools.

Students will also participate in a Crimson Startup, six-week program to learn and apply entrepreneurial skills. Students will be encouraged to develop business ideas related to their research project. During the six-week program, students will spend approximately five to eight hours per week developing and exploring their business idea in small teams with guidance from program instructors.

Electrical Impedance Properties of Bamboo

Faculty Mentor: Dr. Todd Freeborn, Electrical and Computer Engineering

The electrical properties of bamboo are dependent on many factors including the type of material, moisture content, growth process, and post-growth treatment.  Previous REU undergraduates in our group have conducted preliminary literature reviews and pilot studies to investigate bamboo’s electrical properties. The relevant knowledge base is encouraging but limited to a few studies. The goal of this project is to investigate electrical properties of native bamboo species grown in Alabama such as Phyllostachys moso, Phyllostachys rubromarginata, and Phyllostachys nigra to determine their electrical impedance and determine if this property can be used as a method to monitor these materials for changes to heat treatment, chemical treatment, aging, and more. The objectives of this project are: (a) to measure and analyze the electrical impedance of bamboo as a function of frequency and temperature; (b) to analyze and compare the electrical properties of raw and treated bamboo and (c) develop low-cost systems to improve the ability of researchers to collect impedance measurements outside of the laboratory.

REU Participants Role: Prepare bamboo samples, design electrical test fixtures to interface bamboo to test equipment, design circuits for impedance measurements, collect/organize/analyze test data to assess if physical changes are reflected in collected impedance data.  Students will learn to use: (1) impedance analyzers, (2) oscilloscopes, (3) sensing circuits, (4) soldering equipment, and (4) MATLAB analysis tools.

Electrical Properties of Bamboo – A Material with Endless Applications

Faculty Mentor: Dr. Sushma Kotru, Electrical and Computer Engineering

Bamboo is known to be an effective electrical insulator. Electrical properties of bamboo are dependent on many factors such as type of material, moisture content, growth process, and post-growth treatment. Over the last academic year, an undergraduate ECE student conducted a literature review and performed a pilot study to investigate bamboo’s electrical properties. The relevant knowledge base is encouraging but limited to a few studies. The goal of this project is to investigate electrical properties of native bamboo species grown in Alabama such as Phyllostachys moso, Phyllostachys rubromarginata, and Phyllostachys nigra and to find suitable applications. The objectives of this project are: (a) to measure and analyze capacitance, dielectric constant and dissipation factor of bamboo as a function of frequency and temperature; (b) to analyze and compare the electrical properties of raw and treated bamboo (where the lignin is chemically removed;) and (c) to demonstrate the use of the materials in various applications.

REU Participants Role: Prepare samples, design experiments for electrical testing, perform measurements including dielectric constant, capacitance, and the AC and DC conductivity (vertically, radially and horizontally) and compile test data.
Students will learn to use: (1) soldering guns, (2) probe station, (3) impedance analyzer, (4) Keithley meters and (5) software packages such as LabVIEW and Origin.

Faculty Mentor: Dr. Gregory B. Thompson, Metallurgical and Materials Engineering
Faculty Mentor: Dr. Amanda J. Thompson, Clothing, Textiles and Interior Design

Bamboo fiber can be used in a variety of products including nonwovens, textiles for apparel, and home use. Current industrial extraction techniques use either a mechanical or chemical process. The mechanical process uses retting and boiling and is time extensive. The chemical process breaks the cellulose fibers down and regenerates them as rayon, which can be detrimental to the environment and remove any possible natural properties from the fiber. In the proposed project, the REU student will study the processing of bamboo fiber using a steam reaction process and other possible processes. After the fibers have been extracted, the student will characterize their structure, mechanical integrity, and other physical properties including dyeability, anti-microbial attributes, etc. The steam process involves a high temperature high pressure vessel which allows water vapor to infiltrate a bamboo stalk causing the fiber to “explode” from the plant structure. This provides an environmentally friendly or “green” means of fiber extraction. This process has been used in biomass production. To date the processing parameters and effect on the quality of fiber has not been extensively studied. The results of this study will provide a needed database to enable bamboo to be an economically viable crop for Alabama’s agricultural industry.

REU Participants Role: Conduct series of experiments to determine the processing conditions for extraction of bamboo fibers using the steam reactor, testing fibers for mechanical integrity, structure analysis and dyeability. Students will learn to use (1) a laboratory scale steam reactor vessel and other processing equipment, (2) scanning electron microscope (SEM) for structure analysis, (3) fiber tensile testing equipment and methods and (4) variety of dyeing chemicals and color measurement equipment.


Modification of ITO Work Function for Removal of Hole Transport Layer in Perovskite Solar Cells

Faculty Mentor: Dr. Dawen Li, Electrical and Computer Engineering

Rapid advances in power-conversion efficiency and low-cost potentials offered by solution-processing capability of perovskite solar cells (PVSCs) have motivated the development of large-scale production of PVSCs on flexible substrates through high-speed printing. Currently, the record efficiency of PVSCs at the lab scale on glass substrates has surpassed 20%, which is comparable to that of commercialized photovoltaic technologies, such as crystalline silicon based photovoltaics. Recent literature reports show that by modifying the indium tin oxide (ITO) anode, the hole charge transport layer can be removed though this results in slight efficiency reductions. The relevant knowledge base is encouraging but limited to a few studies. The goal of this project is to investigate modifying the indium tin oxide (ITO) work function using chemical methods to remove the hole transport layer while maintaining the overall efficiency. The objectives of this project are: (a) to make PVSCs with stacking layers of ITO/PEDOT/PVSK/PCBM/Al; (b) to modify ITO work function through chlorination, and (c) to compare the performance and achieve high-efficiency PVSCs without hole transport layer.

REU Participants Role: Fabricate PVSCs in glovebox, modify ITO surfaces through chlorination, conduct electrical measurement on PVSC devices, and compare the performance with modification of ITO workfunction at different chlorination treatment periods.  Students will learn: (1) how to make solution, thin-film spin-coating, and thermal evaporation, (2) electrical measurement using semiconductor parameter analyzer, solar simulator, and probe station (3) and Origin software for data processing and analysis.

Multi-Scale Structure-Property-Performance Characterization of Bamboo

Faculty Mentor: Dr. Paul G. Allison, Mechanical Engineering
Faculty Mentor: Dr. Armen Amirkhanian, Civil, Construction, and Environmental Engineering

Bamboo is a fast-growing, plant composed of high-strength fibers that holds potential as a renewable building material, and may be superior to softwood timber in certain applications.  Most bamboo used in the US at present is imported from Asian and South American sources, but recent investments may lead to large-scale domestic cultivation.  The effects of load duration and strain rates (how fast a load is applied) on the strength and stiffness of bamboo are not well understood. Both load duration and strain rates have considerable influence on the same properties of wood and are an important component of determining allowable design strengths in building codes. The same information would be necessary in order for bamboo-based structural members are to be accepted in building codes in the future.

REU Participants Role: Up to two REU students will be teamed with graduate students to investigate the structure-property-performance relationship for bamboos at different length and time scale. This will include very high strain rate testing to simulate blast and impact responses and correlating microstructure to nano-mechanical properties. Students will learn to use (1) electromechanical load frames; (2) split-Hopkinson pressure bar apparatus; (3) nanoindenter; and (4) interpret the data from these tests.

Renewable Power for On-body Electronics

Faculty Mentor: Dr. Edward Sazonov, Electrical and Computer Engineering

The human body and its environment may serve as an endless and renewable power source for on-body electronics, such as physiological sensors. The energy sources such as mechanical motion, body heat, solar and RF energy from the environment can power the electronics, enable data collection, processing and transmission. The goal of this project is to investigate various sources of energy and perform practical experimentation with on-body energy harvesting. The objectives of this project are: (a) to establish the amount of power available from various sources; (b) to experiment with 1-2 energy sources (e.g. body heat and solar) to power an on-body sensors.

REU Participants Role: Perform literature review, use solar and thermal energy harvesting electronics kits to prototype the energy harvesting circuits, develop a microcontroller-based wireless sensor, test of the energy sources with an on-body sensor. Students will learn to use: (1) energy harvesting kits, (2) MATLAB analysis tools, (3) MCU/wireless SDK.

Seismic Performance Evaluation of Bamboo Framing Systems

Faculty Mentors: Dr. Wei Song, and Dr. Michael Kreger, Civil, Construction, and Environmental Engineering
Faculty Mentors: Dr. Mark Barkey, Aerospace Engineering and Mechanics

As a naturally grown material, bamboo’s light weight and relative strength make it a particularly attractive alternative for residential construction in seismic regions. Compared on a mass-per-volume basis to concrete, steel and wood, bamboo is second to concrete for strength, and ranks first for stiffness. However, performance of engineered bamboo products as a predominant structural member in typical building frames remains unknown to researchers. This study will design and implement a small-scale three story building using various bamboo framing systems, and will determine the corresponding performance of the bamboo building frame using shake table tests and dynamic analysis. The experimental results and analysis obtained from this project will provide an opportunity to evaluate the seismic performance of bamboo framing systems, and open the venue to accept bamboo as a construction material in seismic prone areas.

REU Participants Role: REU students will measure the mechanical properties of the engineered bamboo products, and then design, construct, and test the building frame that is enabled by bamboo framing systems. Students will learn (1) equipment use and methods of material testing, (2) structural dynamic behavior and analysis, and (3) shake table testing techniques and associated instrumentation.

Structural Evaluation of Bamboo Subjected to Fatigue Loading

Faculty Mentor: Dr. Steve R. Daniewicz, Mechanical Engineering

Bamboo is an emerging renewable resource that is of interest as a building material in residential construction. Because most structural failures are caused by fatigue, the structural fatigue properties of bamboo must be understood so residential buildings can be built as cheaply as possible and be considered safe. Structural properties of bamboo can vary drastically due to inhomogeneous geometry. The age, species, and moisture content of bamboo can also change the fatigue strength. This study aims to quantify fatigue strength based on these variables using a three-point bend servohydraulic test frame. The results of the experiments will provide useful structural fatigue data that will be used to provide safer living conditions for residential buildings made from bamboo.

REU Participants Role: REU students will work with graduate students to conduct fatigue tests, analysis results, and propose the ideal conditions for bamboo in order to achieve the best fatigue strength. Students will learn: (1) Experimental techniques needed for fatigue testing, (2) Finite element analysis, (3) Fatigue of materials theory, (4) Writing and speaking skills needed to present data.