Research in Flexible Sensors

In Spring 2020, AME granted several Undergraduate Research Opportunity Awards (UROA) to faculty and undergraduate students. Dr. Yingtao Liu and his student, Vincent Webster, received one of these awards, which Phillips 66 sponsored.  Vincent is a senior in aerospace engineering.  About his research, Vincent writes:

My research consisted of developing flexible sensors used in several applications including human motion detection, sensor arrays, soft robotics, biomechanics, structural health monitoring, and prosthetic devices. These sensors measure the force applied to them using a technique called piezoresistivity. Piezoresistivity is characterized as the change in electrical resistance of the material due to an applied deformation. Highly flexible piezoresistive sensors typically decrease their electrical resistance during an applied load. The decrease in resistance occurs due to the variation of microstructures and properties of the materials under loads. To fabricate these sensors, flexible PDMS polymer, was used as the bulk material of the sensor. Carbon nanotubes were uniformly dispersed within the polymer to form the electrical conductive network microstructures. Sugar particles were then added during the fabrication process to create a mixture of carbon nanotube, PDMS, and sugar combination. The sample is then submerged in water to ideally release all the sugar from the sample. The traditional sugar removal method using water can take days to completely remove all the sugar particles. To reduce this extraction time, we would submerge the samples in water and microwave them. This would rapidly increase the temperature of the samples within a minute and the samples would expand and allow water to saturate the sample, leading to the rapid removal of all sugar particles and forming desired open-cell microstructures.

This research built a solid foundation for the rapid manufacturing of piezoresistive polymer foams for broad sensing applications. Our preliminary results have demonstrated that the developed method is able to effectively control materials’ microstructures, enhance carbon nanotube dispersions, and optimize their sensing function. Collaborating with Dr. Liu’s graduate student, Blake Herren, has motivated me to pursue graduate study at OU. Many thanks to the generous support of AME and Phillips 66.

Great job, Vincent!

Research in Ultra-High Thermal Conductivity

Dr. Jivtesh Garg and his graduate students are exploring a new class of ultra-hard boron-carbide materials such as BC2N and BC5 for ultra-high thermal conductivity values. Their goal is to achieve thermal conductivity values higher than diamond and graphene (> 5000 W/mK).

They are using quantum-mechanical calculations based on density-functional theory to predict thermal transport properties. Simultaneously the group is using laser-based frequency-domain thermoreflectance measurements (FDTR) to experimentally measure these high thermal conductivity values. Ph.D. students Rajmohan Muthaiah, Avinash Nayal, and Roshan Annam are conducting this research.

The group has also developed advanced functionalization schemes to more efficiently couple graphene with polymers for thermal transport applications. Graphene is a wonder material with extraordinary thermal, mechanical, and electrical properties. By efficiently coupling graphene with polymer, a large enhancement in properties can be achieved. Initial experimental results suggest dramatic improvement in the thermal conductivity of polymers such as polyetherimide. Developed functionalization schemes are being applied to a wide range of polymers. Ph.D. students Fatema Tarannum and Swapneel Danayat are involved in this research.

They are further exploring non-equilibrium phonon effects for the design of high-efficiency hot carrier solar cells and thermoelectric materials. Electrons in solar cells thermalize through interactions with lattice vibrations (phonons). By engineering non-equilibrium phonon effects to generate hot phonons, the thermalization of electrons can be inhibited, thereby enhancing solar cell efficiency. Non-equilibrium phonon effects also enhance the efficiency of thermoelectrics by mitigating heat loss through lattice vibrations.  Fundamental first-principles techniques coupled with Monte-Carlo simulations are being used to study non-equilibrium phonon effects.

Through advanced simulations and state-of-the-art experimental measurements, the group aims to develop the next generation of advanced composite materials for thermal management and energy conversion applications and is a world leader in thermal management technologies.

 

Using EEG to Understand Engineering Creativity

Tess Hartog, Md Tanvir Ahad, and Amin Alhashim are working together to explore the uses of electroencephalogram (EEG) to understand neuro-responses as they pertain to creativity in engineering. They are working under Dr. Zahed Siddique; Tess Hartog is an ME MS student with a background in math and psychology, Tanvir is an ME Ph.D. student with a background in EE, and Amin is an ISE Ph.D. student. Megan Marshall was a former fellow who graduated with her MS in AE in the summer of 2020.

The main objective of the research is to study creativity in engineering by gaining a deep understanding of how creative thoughts form and how the brain responds to different levels of creative products.  The students are currently utilizing EEG to capture the neurological behaviors and responses when conducting research.

Graduate Students

Amin’s work focuses on three areas: creativity definitions, creativity models, and the effect of cues on creativity.  Through text analysis techniques, Amin is analyzing a corpus of creativity definitions extracted from literature to understand how creativity is being perceived by engineers and non-engineers.  There are many models for creativity and Amin is working on a classification scheme based on their similarity.  Such classification is important for the advancement of creativity research as evident in the history of sciences. Amin’s last area of focus is on the effect of cues on creative behavior and its relationship with how the brain behaves through the use of EEG.

 

Tess’s work focuses on a subset of EEG recording called event-related potentials (ERPs), which are time-locked neural responses to stimuli. Specifically, she investigates the ERPs (the N400response) of engineers to creative stimuli. Tess is also working on analyzing the EEG recordings of engineers during engineering design-related problems and examining whether exposure to creative stimuli will improve designs. Below are some of her preliminary ERP findings. As indicated in the pictures, she looks for differences in negative wave amplitudes for three types of stimuli around 400 milliseconds post-stimulus presentation (i.e. the N400).

 

Defining creativity is hard but the measurement of creativity is even harder. To capture the multifaceted nature of creativity; more than a hundred measurement techniques have been developed and applied including neurocognitive approaches. The brain’s neural dynamics related to creativity should be accounted to quantify the relationship between the brain regions. During divergent thinking, EEG studies aid temporal dynamics of the neuronal activations underlying cognitive insight. In order to solve real-world problems, creativity is a must for engineers. Engineers’ involvement with creative tasks; activate brain regions corresponding to the task’s demand. Identifying the significant brain temporal regions engaged with the creative tasks for engineers is a crucial question. Brain-computer interfaces (BCIs) which are based on event-related potentials (ERPs) have the potential ability to estimate a user’s task involvement. Therefore, the question comes: Is the creativity (neural activity) of engineers detected by ERP-Based Brain-Computer Interfaces task-specific? Tanvir’s research work focuses on addressing these questions in the Neurocognitive creativity research domain.

Gollahalli Legacy Fund

 

 

Professor Subramanyam Gollahalli, Lesch Centennial Chair at the University of Oklahoma (OU) School of Aerospace and Mechanical Engineering (AME), retired and transitioned to emeritus status in May 2017, after 41 years of service at OU (52 years including his tenure at the Indian Institute of Science, India and the University of Waterloo, Canada). His service included eight years of directorship at AME.

His distinguished career was marked by many awards from various professional organizations and many recognitions from OU, including the Regents Superior Teaching Award and Regents Professional Service Award. A few of the awards bestowed upon Professor Gollahalli are the Westinghouse Gold Medal, the Energy Systems Award, the Ralph James Award, the Ralph Teetor Award, the Samuel Collier Award and the Sustained Service Award.

Professor Gollahalli’s research in energy and combustion involved many experimental studies. He founded the internationally-recognized Combustion Laboratory, where he mentored over 100 graduate students (M.S. and Ph.D.) and post-doctoral associates and produced nearly 300 publications. He involved many undergraduate students in his laboratory research as well.

Professor Gollahalli strongly believes that “hands-on experimental experience” is an essential component of engineering education to prepare well-rounded engineers. He was the founding chair of the AME Laboratory Committee (1989), in which capacity he served until retirement (with a break during his directorship). He was the author of the “AME Lab Plan” required by the accreditation agency, which provides guidelines for various laboratories (two required labs and five elective labs). It deals with coordination, safety aspects and general guidelines for funding and conducting laboratory courses. During his tenure as the chair, he raised funds and arranged allocation of funds through the Lab Committee to modernize the lab education to keep pace with technological innovations.

“Dr. Gollahalli is a truly dedicated professor, he inspires his students to solve problems and make a difference,” said Sai Gundavelli, AME alum.

His passion for giving students hands-on experience resulted in the modernization of the AME machine shop with numerically controlled equipment. During his directorship, he gave priority to funding labs and the machine shop in which students were given the opportunity to work by themselves under the supervision of machine shop staff.

The capstone design project program, which involves industrial projects, saw a major growth in size and increase in funding during his directorship. The AME Capstone Project Poster Fair, where students exhibit their hands-on developed creations and win awards at the conclusion of judging by the industry personnel, became an annual popular event during his term as the director.

During his tenure as the director, he encouraged and supported the student competition activities, such as Sooner Racing Team, Human-Powered Vehicle Team, Robotics Team and Design-Build-Fly Team. The teams facilitated direct student involvement in designing, manufacturing and competing in national events. He personally attended some of the competitions to encourage students. He took great pleasure and felt proud when the teams achieved high national rankings.

When Professor Gollahalli stepped down from the directorship after eight years, the AME Board of Advisors started a fund to honor his legacy, which was intended to support the undergraduate laboratories. Now, after his retirement, to mark his passion and belief in providing valuable laboratory hands-on experience to students, Professor Gollahalli’s family decided to make a significant contribution to this fund to make it a permanent endowment, which will serve as a source of funding for this cause.

“I am grateful to the AME Board of Advisors for establishing Gollahalli Legacy Fund to support instructional labs. I thank my wonderful students and friends for their generous donation for this cause, which will facilitate production of well-rounded future AME engineers,” said Professor Gollahalli.

The School of AME requests your contributions to this fund to mark your name and help fulfill Professor Gollahalli’s long-standing desire. To contribute to the Gollahalli Legacy Fund please visit: https://giving.oufoundation.org/OnlineGivingWeb/Giving/OnlineGiving/Gollahalli