Article
Physics, Applied
C. Wang, A. Kanj, A. Mojahed, S. Tawfick, A. Vakakis
Summary: In this study, we investigate a dissipative network consisting of two asymmetric semi-infinite nonlinear lattices with weak linear inter-lattice coupling, focusing on passive wave redirection and non-reciprocity. We found that irreversible breather redirection occurs in this network under specific conditions, with motion localization happening otherwise. By analyzing the acoustic non-reciprocity and formulating a quantitative measure based on time-series responses, we demonstrate the relationship between non-reciprocity and the intensity of the applied impulse. These findings lay the groundwork for designing practical nonlinear lattice networks with self-adaptive capacities for passive wave redirection and tunable acoustic non-reciprocity.
JOURNAL OF APPLIED PHYSICS
(2021)
Article
Multidisciplinary Sciences
Hetao Chu, Xinghao Hu, Zhong Wang, Jiuke Mu, Na Li, Xiaoshuang Zhou, Shaoli Fang, Carter S. Haines, Jong Woo Park, Si Qin, Ningyi Yuan, Jiang Xu, Sameh Tawfick, Hyungjun Kim, Patrick Conlin, Maenghyo Cho, Kyeongjae Cho, Jiyoung Oh, Steven Nielsen, Kevin A. Alberto, Joselito M. Razal, Javad Foroughi, Geoffrey M. Spinks, Seon Jeong Kim, Jianning Ding, Jinsong Leng, Ray H. Baughman
Summary: The study found unipolar stroke carbon nanotube yarn muscles with enhanced stroke, contractile work-per-cycle, contractile power densities, and energy conversion efficiencies, offering potential for expanding their applications.
Article
Engineering, Manufacturing
Davis J. McGregor, Samuel Rylowicz, Aaron Brenzel, Daniel Baker, Charles Wood, David Pick, Hallee Deutchman, Chenhui Shao, Sameh Tawfick, William P. King
Summary: This study evaluates the accuracy of polymer parts made on three identical printers and examines the impact of manufacturing process parameters on part variability. The research finds that geometric defects in wall thickness depend on machine and location, while defects in wall length and height depend on machine and tool. Additionally, the uniformity within parts mostly depends on unmeasured parameters.
ADDITIVE MANUFACTURING
(2021)
Article
Chemistry, Multidisciplinary
SunPhil Kim, Jonathan Bunyan, Paolo F. Ferrari, Ali Kanj, Alexander F. Vakakis, Arend M. van der Zande, Sameh Tawfick
Summary: Thermal induced elastic buckling of resonators in waveguides can lead to phase transitions, allowing reversible control of signal transmission. The merging of lower and upper band gaps results in localized signals at the excitation boundary, opening up opportunities for drastic phononic band reconfiguration in on-chip circuitry and computing.
Article
Nanoscience & Nanotechnology
A. Kanj, C. Wang, A. Mojahed, A. Vakakis, S. Tawfick
Summary: The study experimentally investigates wave redirection, localization, and non-reciprocity in nonlinear lattice systems, demonstrating tunable wave tailoring properties of the system with energy. The experimental results validate the theoretical predictions and show the efficacy of the system for applications in future structures and devices.
Article
Physics, Applied
Ganesh Ananthakrishnan, Mitisha Surana, Matthew Poss, Jad Jean Yaacoub, Kaihao Zhang, Nikhil Admal, Pascal Pochet, Sameh Tawfick, Harley T. Johnson
Summary: The study demonstrates the role of graphene in maintaining faceted surface morphology, suppressing surface melting and surface diffusion, and providing thermo-mechanical interfacial surface stabilization, which is crucial for understanding most metal-graphene interfaces and producing defect-free graphene for applications.
JOURNAL OF APPLIED PHYSICS
(2021)
Article
Chemistry, Physical
Jonghyun Ha, Yun Seong Kim, Ryan Siu, Sameh Tawfick
Summary: Drying of fine hair and fibers can lead to significant capillary-driven deformation, resulting in self-assembly of hair bundles into various shapes under high drain rates. The mechanism of self-assembly involves two stages: first, the liquid covers the outside of the bundles and facilitates fiber rearrangement, then the liquid drains from within the fiber spacing causing the fibers to pack tightly. Understanding dynamic elastocapillarity provides insights into the complex physics of wet granular drying.
Article
Mechanics
Jonghyun Hwang, Jonghyun Ha, Ryan Siu, Yun Seong Kim, Sameh Tawfick
Summary: The chemical and physical reactions that occur during cooking connect us to science on a daily basis. In this study, the swelling and softening of pasta due to liquid imbibition, as well as the elastic deformation and adhesion of pasta due to capillary force, were investigated both theoretically and experimentally. The softening of pasta during cooking follows three sequential regimes, and is associated with changes in microstructure. Notably, the study found that the cooking time and the amount of salt added to the boiling water have a significant impact on the texture and elasticity of the pasta.
Article
Chemistry, Physical
Oleg Davydovich, Justine E. Paul, John David Feist, Jia En Aw, Francisco Javier Balta Bonner, Jacob J. Lessard, Sameh Tawfick, Yan Xia, Nancy R. Sottos, Jeffrey S. Moore
Summary: Frontal ring-opening metathesis polymerization (FROMP) is a rapid, low-energy manufacturing reaction used for curing thermosetting materials. Incorporating cleavable units in the chain segments allows for the deconstruction of thermosets. 2,3-dihydrofuran (DHF), acting as both a potent Grubbs catalyst inhibitor and an acid cleavable unit, enables the production of high-performance deconstructable thermosets.
CHEMISTRY OF MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Mitisha Surana, Ganesh Ananthakrishnan, Matthew M. Poss, Jad Jean Yaacoub, Kaihao Zhang, Tusher Ahmed, Nikhil Chandra Admal, Pascal Pochet, Harley T. Johnson, Sameh Tawfick
Summary: The study investigates the impact of interfacial interaction between 2D materials and the substrate on the electronic properties, and quantitatively analyzes the orientation-dependent facet topographies observed on graphene using electron backscatter diffraction and atomic force microscopy. Molecular simulations reveal that apart from anisotropic interfacial energy, graphene strain plays a critical role in forming the observed topographies. These findings are also applicable to other 2D/3D heterostructures.
Article
Materials Science, Multidisciplinary
Aagam Shah, Joshua A. Schiller, Isiah Ramos, James Serrano, Darren K. Adams, Sameh Tawfick, Elif Ertekin
Summary: In this work, we demonstrate a neural network that automatically distinguishes between pixels in SEM images corresponding to regions with and without graphene. The trained model shows an accuracy of over 90% and an F1 score over 80%. The network also exhibits reasonable performance when applied to other 2D materials, suggesting the potential for transfer learning.
MATERIALS TODAY COMMUNICATIONS
(2023)
Article
Acoustics
Ali Kanj, Alexander F. Vakakis, Sameh Tawfick
Summary: On-chip phononic circuits enable customized transmission of elastic waves and can couple with electronics and photonics for new signal manipulation capabilities. A reduced-order model is constructed to demonstrate the transmission switching mechanism in coupled drumhead-resonator waveguides, showing how thermoelastic buckling induces phase transition and localization of frequency passband modes.
JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA
(2023)
Article
Engineering, Mechanical
Ali Kanj, Paolo Ferrari, Arend M. van der Zande, Alexander F. Vakakis, Sameh Tawfick
Summary: Nonlinear micro-electro-mechanical systems (MEMS) resonators offer new opportunities in sensing and signal manipulation through frequency tuning and increased bandwidth. This study designs, fabricates, and investigates drumhead resonators with strongly nonlinear dynamics, developing a reduced order model (ROM) to accurately capture their response. The resonators exhibit electrostatically-mediated thermoelastic buckling, with a tunability factor of 2.4x and switching between stiffness and softness.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2023)
Article
Instruments & Instrumentation
Samuel Tsai, Qiong Wang, Yuzhe Wang, William P. King, Sameh Tawfick
Summary: This paper presents a method of manufacturing elastomeric robots using bioinspired kinematic design, coiled artificial muscle actuators, and projection additive manufacturing (AM). A fleet of 108 robot designs were designed and tested using high-speed AM. The smallest tested robot had a length of 7.5 mm, a mass of 0.216 g, and could jump 60 times its body size in horizontal distance. The robot could jump while carrying an integrated control system and power source for self-triggered jumping.
SMART MATERIALS AND STRUCTURES
(2023)
Article
Multidisciplinary Sciences
Jonghyun Ha, Yun Seong Kim, Chengzhang Li, Jonghyun Hwang, Sze Chai Leung, Ryan Siu, Sameh Tawfick
Summary: Soft robots have successfully achieved switchable visual contrast and multipixel displays using capillary-controlled robotic flapping fins. This technology is more energy efficient compared to traditional light emitting devices and electronic paper, and it also offers ultralow power consumption, scalability, and mechanical compliance.
