Introducing Creativity In A Design Laboratory For A Freshman Level Electrical And Computer Engineering Course

In the electrical and computer engineering (ECE) curriculum at The University of Alabama, freshmen are introduced to fundamental electrical concepts and units, DC circuit analysis techniques, operational amplifiers, circuit simulation, design, and professional ethics. The two credit course has both lecture and laboratory components that address these topics. The laboratory has been used, in this project, to provide students an experience in design. In one of the laboratory assignments, students work in teams to design and build products giving attention to both function and aesthetics. Creativity is an important attribute for engineers practicing their profession in a global society. The creative process was exercised in the design lab by progressively engaging students through various stages including: brainstorming, formation of a construction plan, producing schematic representations, and implementing their design. In a two- year period, four laboratory exercises were developed to provide design experiences in our introductory ECE course. Assessment results show that the majority of students enjoy several aspects of the laboratory on design and creativity. At the same time, they consider this lab to be one of the most difficult ones due to its open-ended nature. Students who experienced the creative lab were somewhat more likely to state they would continue in their major. Overall, the project team concluded that the creative lab was valuable and did raise awareness of the creative process.

On the mechanisms of DC conduction in electrospun PLZT/PVDF nanocomposite membranes

Designing dielectric nanocomposite films with excellent dielectric properties is of strategic importance for a variety of applications requiring pressure sensing, energy harvesting and storing, and biomedical technology. Hence, the present investigation aims at studying the dielectric properties of lead lanthanum zirconate titanate (PLZT)/poly(vinylidene fluoride) (PVDF) nanocomposite based membranes fabricated using traditional electrospinning techniques. The composites were investigated for structural and electrical conductivity properties at varying temperatures. While the Scanning Electron microscope revealed beaded and unannealed micro/nanofibers, the observations of temperature-dependent electrical conductivity imply that the charge carrier transport phenomena involve more than one conduction mechanism. This is an interesting observation and can be explained in terms of the contents and porosity of the composites. As compared to PVDF, PLZT/PVDF nanocomposite films have somewhat better conductivity. The space charge limited current was the dominant mechanism at high voltages, while the Schottky–Richardson conduction mechanism was dominating at high temperature, according to observed J–V characteristics. The DC activation energy was found to be different, as expected, due to the dynamically heterogeneous nature of PLZT aggregates within the polymer matrix; however, the films exhibit the well-known Arrhenius relationship. This indicates that the dominant conduction mechanism is observed to be electronic and thermally activated. Graphical abstract: [Figure not available: see fulltext.]</p

On the mechanisms of DC conduction in electrospun PLZT/PVDF nanocomposite membranes

Designing dielectric nanocomposite films with excellent dielectric properties is of strategic importance for a variety of applications requiring pressure sensing, energy harvesting and storing, and biomedical technology. Hence, the present investigation aims at studying the dielectric properties of lead lanthanum zirconate titanate (PLZT)/poly(vinylidene fluoride) (PVDF) nanocomposite based membranes fabricated using traditional electrospinning techniques. The composites were investigated for structural and electrical conductivity properties at varying temperatures. While the Scanning Electron microscope revealed beaded and unannealed micro/nanofibers, the observations of temperature-dependent electrical conductivity imply that the charge carrier transport phenomena involve more than one conduction mechanism. This is an interesting observation and can be explained in terms of the contents and porosity of the composites. As compared to PVDF, PLZT/PVDF nanocomposite films have somewhat better conductivity. The space charge limited current was the dominant mechanism at high voltages, while the Schottky–Richardson conduction mechanism was dominating at high temperature, according to observed J–V characteristics. The DC activation energy was found to be different, as expected, due to the dynamically heterogeneous nature of PLZT aggregates within the polymer matrix; however, the films exhibit the well-known Arrhenius relationship. This indicates that the dominant conduction mechanism is observed to be electronic and thermally activated. Graphical abstract: [Figure not available: see fulltext.]</p

Damage detection in composite materials using PZT actuators and sensors for structural health monitoring

Structural Health Monitoring (SHM) of bridges, buildings, aircrafts, and spacecraft using a network of sensors has gained popularity over recent years. In this thesis, the use of piezoelectric actuators and sensors is described for detecting damage in a composite panel. The composite panels are fabricated using the Vacuum Assisted Resin Transfer Molding (VARTM) process. The panels are cut into small coupons (254 mm x 25.4 mm) to test various properties of the composite. A piezoelectric actuator is surface mounted on the composite coupon to generate Lamb waves while a surface mounted piezoelectric sensor measures the response. Data is collected from an undamaged composite coupon, and then the process is repeated for a damaged coupon. The existing damage is quantified by comparing the response of the damaged and undamaged composite coupons. (Published By University of Alabama Libraries