Author: Orlando E

Mathematical and Computational modelling of soft-tissue mechanobiology: application to aneurysms, osteoarthritis and bladder outlet obstruction.

Abstract: Mathematical and computational modelling approaches can quantify the mechanics & mechanical environment of soft biological tissues under physiological and pathological loading. These tools can quantify ‘mechanical stimuli’ inputs to algorithms that control growth and remodelling (G&R) of the tissue to simulate adaptation to altered environmental conditions. In this talk, I will overview a rate-based constrained mixture G&R modelling approach which was developed to create the first computational model of aneurysm evolution [1]; I will then summarise its sophistications and applications over the past 20 years. In general, the modelling approach is as follows: the constitutive model of the tissue accounts for the individual natural reference configurations of cells and matrix components; a model of the organ/tissue is defined/calibrated to initially be in homeostasis in the physiological loaded configuration; subsequent tissue loss/damage or changes to the mechanical environment can change the distribution of mechanical stimuli from homeostatic setpoints and drive G&R processes that lead to the progression of disease or the adaptation to a new homeostatic state. Illustrative applications of the approach will include fluid-solid-growth frameworks for modelling intracranial aneurysm evolution [2], in vivo-in vitro-in silico modelling of bladder adaption to outlet obstruction [3] and a conceptual chemo-mechano-biological model of cartilage evolving in health, disease and treatment [4]. Outlook for future research and clinical translation of the models will be discussed.

References:

[1] Watton, Hill & Heil (2004) A Mathematical Model for the Growth of the Abdominal Aortic Aneurysm, BMMB, 3:98-113.

[2] Teixeira et al. (2020) Modeling intracranial aneurysm stability and growth: an integrative mechanobiological framework for clinical cases. BMMB, 19:2413–2431.

[3] Cheng et al. (2022) A constrained mixture-micturition-growth (CMMG) model of the urinary bladder: Application to partial bladder outlet obstruction (BOO), JMBBM, 134: 105337.

[4] Rahman et al. (2023) A chemo-mechano-biological modelling framework for cartilage evolving in health, disease, injury, and treatment, CMPB, 231: 107419.

 

Biographical Sketch: Paul Watton is Head of the Complex Systems Modelling Group and Professor of Computational and Theoretical Modelling at the Dept. of Computer Science & Insigneo Institute for in silico Medicine at the University of Sheffield, UK. He also holds an adjunct position with the Dept. of Mech. Eng. and Materials Science, University of Pittsburgh, US. He has a mathematical background (BSc Pure & Applied Mathematics, MSc Mathematical Logic, PhD Applied Mathematics) and his research focuses on modelling the biomechanics & mechanobiology of soft-biological tissues with application to disease progression and treatment.

We Welcome 3 New Faculty: Profs. Chisthy, Duduta, and Liu

Wajid ChishtyDr. Wajid Chishty joined our school as an in-residence Full Professor in January 2023. In the realm of academia, Dr. Wajid Chishty has consistently demonstrated exceptional accomplishments. He earned his MBA in Finance from The University of Karachi in 1991, followed by an MS degree in Aerospace Engineering from the University of Michigan in 1996. In 2005, he obtained his PH.D in Mechanical Engineering from Virginia Polytechnic & State University.

With over three decades of engineering experience under his belt, Dr. Chishty brings a wealth of expertise to our department. His primary areas of expertise include “gas turbine maintenance”, where he applies his skills to aerospace engines, and combustion research which is a study about how things burn; a field crucial for enhancing the environmental efficiency of aerospace engines.

Beyond his professional achievements, Professor Chishty is an active contributor to academia. Chishty is an educator who has authored numerous publications in topics surrounding engineering mechanics, with a portfolio of more than 50 research papers.

Dr. Chishty is a respected member of several esteemed organizations, including the American Society of Mechanical Engineering (ASME) who are dedicated to promoting “the art, science and practice of multidisciplinary engineering and allied sciences” (asme.org) worldwide. He is also affiliated with the American Society for Engineering Education (ASEE), a non-profit founded in 1893 aimed at advancing engineering and its education practices. Additionally, Dr Chishy is a member of the American Institute of Aeronautics and Astronautics (AIAA), a U.S representative of the International Astronautical Federation and the International Council of Aeronautical Sciences.

Duduta, MihaiMishu Duduta‘s academic journey is truly remarkable. He earned his Bachelor’s degree in Material Science from MIT in 2010, demonstrating his early passion for science. Dr. Duduta graduated in 2019 with an Engineering Sciences PhD degree from Harvard University, with a thesis titled “Dielectric Elastomer Actuators as Artificial Muscles for Soft Robotic Applications.” His outstanding research earned him the prestigious Gold Award from the Materials Research Society in 2018 and a nomination for Best Paper at ICRA. Dr. Duduta’s list of awards and grants is extensive, with support from foundations both nationally and internationally. His contributions to research have led to multiple publications and citations, solidifying his presence in the academic world.

Prior to joining UConn in August 2023 as an Assistant Professor, Professor Duduta enriched his academic and professional journey with diverse experiences. After completing his post-doctoral studies at the University of Minnesota, Medical Devices Innovation Fellow where he developed a soft robotic tools for neurointervention. He served as an Assistant Professor at The University of Toronto. His pioneering work in developing the biomedical tool showcases his dedication to innovation in the field. Currently, he leads the Duduta Research Group, known for its pioneering work in biomedical robotics and its global recruitment of Ph.D. students.

 

Chang Liu joined our school as an Assistant Professor in August 2023. Dr. Liu’s educational journey commenced at Shanghai Jiao Tong University in 2017, where he earned not one, but two Bachelor’s degrees in Naval Architecture and Ocean Engineering as well as Computer Technology and its Applications. However, Liu’s desire for knowledge did not end there. He continued his educational pursuit, obtaining a Master’s in Mechanical Engineering in 2020 and a Master of Science in Applied Mathematics and Statistics in 2021 at Johns Hopkins University. In a testament to his dedication and scholarly prowess, Liu successfully completed his Ph.D. in Mechanical Engineering also in 2021 at JHU.. Subsequently, he embarked on postdoctoral research at the University of California, Berkeley from 2021 to 2023.

Liu’s research centers on unraveling and harnessing the complex dynamics of fluids and gasses, such as the flow of water in rivers or the turbulence, when the water gets choppy. His primary objectives are to decipher methods for controlling these intricate forces and forecasting their behaviors.

Chih-Jen (Jackie) Sung receives the Prestigious 2024 AIAA Energy Systems Award

Chih-Jen SungProf. Jackie Sung was awarded the 2024 AIAA Energy Systems Award for his significant contribution in the broad field of energy systems, and specifically for his outstanding contributions to flame dynamics and low-temperature chemistry for developing fuel-flexible, ultra-low emission, efficient combustion energy systems using conventional and alternative fuels.

He will be recognized during the 2024 AIAA SCITECH Forum, 8-12 January 2024 in Orlando, FL. The prestigious award is sponsored by the AIAA Terrestrial Energy Systems.

Dr. Sung’s research and teaching interests have included structure of chemically reacting flow, catalytic combustion, micro-propulsion, laser diagnostics, supersonic combustion, unsteady and high-pressure flame phenomena, soot and NOx formation, flame extinction and ignition, development of detailed and reduced chemical kinetic models, alternative fuel utilization and combustion, and clean combustion technology. His research is funded by various federal and industrial sponsors. He is a Fellow of the American Society of Mechanical Engineers (ASME) and the Combustion Institute, an Associate Fellow of the American Institute of Aeronautics and Astronautics (AIAA), an elected member of the Connecticut Academy of Science and Engineering, and a member of the Editorial Board for Combustion Theory and Modelling.

Morphology, optical properties & climate impact of soot nanoparticles

Abstract: Soot is a major air pollutant produced by incomplete combustion of hydrocarbon fuels. The contribution of soot to global warming is currently estimated with large uncertainty (partly) due to the fractal-like agglomerate structure of its constituent nanoparticles. Here, the dynamics of soot nanoparticles are investigated to advance our current understanding of particle formation during combustion. Discrete element modeling (DEM) enables the detailed description of the particle morphology (doi.org/10.1016/j.proci.2016.08.078) and optical properties (doi.org/10. 1016/j.proci.2018. 08.025) in population balance models and computational fluid dynamics (doi.org/10.1016/j.combustflame.2021.01.010). Power laws relating the optical properties of soot to its filamentary structure are derived by DEM (doi.org/10.1016/j.carbon.2017.06.004) to facilitate the accurate monitoring of soot emissions by aerosol (doi.org/10.1016/j.proci.2020. 07.055), laser (doi.org/10.1016/j.combustflame.2022.112025) diagnostics and fire detectors (doi.org/10.1016/j.powtec.2019.02.003). Most importantly, these relations enable the estimation of the soot direct radiative forcing accounting for its realistic agglomerate structure (doi.org/10.1021/acs.est.2c00428).

Biographical Sketch: Dr. Georgios Kelesidis is an Assistant Professor at Rutgers School of Public Health and Deputy Director of the Nanoscience and Advanced Materials Center of the Environmental and Occupational Health Sciences Institute at Rutgers University. Prior to this appointment, he was a Lecturer and Research Associate at the Department of Mechanical and Process Engineering of ETH Zürich, Switzerland. He received a Diploma in Chemical Engineering from the University of Patras, Greece with honors (top 3%), along with the Limmat Stiftung Award of Academic Excellence (2013). His subsequent MSc studies in Process Engineering at ETH Zürich were supported by a Particle Technology Laboratory Fellowship (2013-2015), while his MSc thesis earned the IBM research prize (2017) for computer modelling and simulations in chemistry, biology and material science. His 2019 PhD thesis on the morphology and optical properties of flame-made nanoparticles received the 2020 PhD Award from GAeF (German Association for Aerosol Research) and the ETH medal for Outstanding Doctoral Thesis (top 8 %). He received also the 1st Graduate Student Award on Carbon Nanomaterials at the 2019 AIChE Annual Meeting (Orlando, FL, USA), as well as Best Poster Awards at the European Aerosol Conference (EAC) in 2016 (Tours, France) and 2020 (Aachen, Germany), the 2019 ETH Conference on Combustion Generated Nanoparticles (Zürich, Switzerland) and the 2019 Fall Meeting of the Material Research Society (MRS). The societal impact of his PhD research was also highlighted by the Forbes Magazine by including him in the 2020 Forbes 30 under 30 Europe list for Science & Healthcare. He has co-authored 21 peer-reviewed articles so far, being the first author in 16 of them. He has organized technical sessions at MRS (2016), EAC (2019-2021), the 2020-2022 Annual Meetings of the American Association for Aerosol Research, the 11th International Aerosol Conference (2022) and the 9th World Congress on Particle Technology (2022). He has supervised so far 10 MSc and 7 BSc students. He is currently co-supervising 1 PhD student at ETH Zürich.

Strategies to Incorporate Mechanics and Manufacturability in Topology Optimization

dr carstensenAbstract: Recent decades have seen rapid development in all manufacturing technologies, including additive manufacturing (AM). This has raised the need for design methods to leverage the new, increasingly complex fabrication possibilities. Topology optimization has the potential to generate new high-performing design solutions since it is a free-form design method that does not require a preconceived notion of the final layout. It uses computational mechanics and optimization tools to generate improved designs. For operating designs to perform as predicted, the used model must capture the material behavior. Additionally, the planned manufacturing process might induce material characteristics and design limitations that should be considered as the design is generated. This talk focuses on identifying and incorporating behavioral and manufacturing aspects within the design process. Different strategies for integration within topology optimization will be discussed. This includes consideration of manufacturing-induced material characteristics, which is illustrated through tailoring design to material extrusion-based AM. In material extrusion, a nozzle moves across a build plate and deposits a material bead on a 2D slice of the design. These processes typically induce some degree of anisotropy through weak(er) bonding between adjacent beads. To improve the manufacturability of large-scale designs, the application of a Mixed Integer Linear Programming formulation is discussed for highly restricted volume scenarios. Finally, a new design framework is introduced in which the interactive participation of the design engineer is enabled to resolve more complex mechanic phenomena.

Biographical Sketch: Josephine Carstensen is the Gilbert W. Winslow Career Development (Assistant) Professor in the Department of Civil and Environment Engineering (CEE) at MIT. She leads the Carstensen Group, conducting research that revolves around the engineering question of “how we design the structures of the future?” Her work spans from the development of computational design frameworks for various structural types and design scenarios to experimental investigations that are used to inform necessary algorithmic considerations.

Dr. Carstensen has received awards for both research and teaching, including the National Science Foundation CAREER award and CEE Maseeh Award for Excellence in Teaching. She joined the MIT CEE faculty in 2019 after two years as a lecturer at MIT, jointly appointed in CEE and Architecture.  She received her PhD from Johns Hopkins University in 2017 and holds a B.Sc. and a M.Sc. from the Technical University of Denmark.

Adaptive robotic systems using embodied intelligence

Abstract: Current robots are primarily rigid machines that exist in highly constrained or open environments such as factory floors, warehouses, or fields. There is an increasing demand for more adaptable, mobile, and flexible robots that can manipulate or move through complex environments. This problem is currently being addressed in two complementary ways: (i) learning and control algorithms to enable the robot to better sense and adapt to the surrounding environment and (ii) embedded intelligence in mechanical structures. My vision is to create robots that can mechanically conform to the environment or objects that they interact with to alleviate the need for high-speed, high-accuracy, and high-precision controllers. In this talk, I will give an overview of our key challenges and contributions to developing mechanically conformable robots, including soft parallel mechanisms for dexterous manipulation, physically-coupled multi-agent systems, and dynamic origami.

Biographical Sketch: Zeynep Temel is an Assistant Professor with the Robotics Institute at Carnegie Mellon University. Her research focuses on developing robots that can mechanically conform to the environment or objects that they interact with. Prior to joining RI, she was a postdoctoral Fellow at the Microrobotics Lab in Harvard University. She received her Ph.D. from Sabanci University, Turkey, where her work is funded by Turkish Science Foundation. In 2020, she was selected as one of 25 members of the Young Scientists Community of World Economic Forum.

Gel Repairs Cartilage Without Surgery, With Electricity

Instead of requiring surgery to insert a solid scaffold, the gel could be simply injected into the knee, a much less invasive procedure

Prof. Thanh Nguyen (right) and graduate student Tra Vinikoor (left).

A lifetime of activity can gradually erode the cartilage that cushions our joints. Someday, we might simply inject a gel to repair it, University of Connecticut researchers report in the Oct. 6 issue of Nature Communications.

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We Are Now the School of Mechanical, Aerospace, and Manufacturing Engineering

Dear UConn Mechanical Engineering Alumni, Friends, and Colleagues,

I am thrilled to announce that, effective today, November 1, 2023, our department of mechanical engineering has become the School of Mechanical, Aerospace, and Manufacturing Engineering that is part of UConn’s new College of Engineering.

This marks a significant milestone in our department’s academic evolution and represents the logical progression in our journey, showcasing the depth and breadth of our academic successes. For example, during the last 6 years, our research activity has more than tripled; we have made decisive strides towards our educational mission, we have significantly increased the diversity of our faculty and students as well as the size of our student population, and we have established the first large multimillion dollar research center focused on modeling and simulation in collaboration with the US Army.

The transition to the School of Mechanical, Aerospace, and Manufacturing Engineering opens up many other opportunities in our development, including the promotion of interdisciplinary collaborations, the introduction of innovative degree programs tailored to industry needs at the state and national levels, as well as the expansion of our research portfolio and of our global influence.

This accomplishment would not have happened without the unwavering support of our community, particularly our dedicated alumni and friends, for which we are deeply grateful. Your contributions have played a pivotal role in shaping our legacy of academic excellence and innovation, so please remain actively involved as we explore this exciting new frontier.

In the meantime, I remain eager to hear your thoughts and perspectives that could further enhance our strength and growth.

Sincerely,

Horea Ilies
Director, School of Mechanical, Aerospace, and Manufacturing Engineering
University of Connecticut

Measurement of non-equilibrium in high-speed hydrogen jet flames using spontaneous Raman scattering

Abstract: Mixing-induced vibrational non-equilibrium was studied in the turbulent shear layer between a high-speed jet and a surrounding hot-air co-flow. The vibrational and rotational temperatures of N2 and O2 were determined by fitting measured spontaneous Raman scattering spectra to a model that allows for different vibrational and rotational temperatures. The mixing of the jet fluid with the co-flow gases occurs over microsecond time scales, which is sufficiently fast to induce vibrational non-equilibrium in the mixture of hot and cold gases. The effect of fluctuating temperatures on the time-averaged Raman measurement was quantified using single-shot Rayleigh thermometry. The Raman scattering results were found to be insensitive to fluctuations except where the flame is present intermittently. Vibrational non-equilibrium was detected in nitrogen but not in oxygen. This difference between species temperatures violates the two-temperature assumption often used in the modeling of high-temperature non-equilibrium flow. A multiple-pass cell was constructed to obtain single-shot Raman scattering measurements in the turbulent shear layer using a pulsed stretched laser. These measurements agreed with the previous time-average results and allowed us to make measurements near the fluctuating base of a lifted flame – a region where time-averaged measurements do not give meaningful results.

Biographical Sketch: Prof. Philip L. Varghese holds the Ernest H. Cockrell Centennial Chair in Engineering at The University of Texas at Austin and has an international reputation in the areas of rarefied and non-equilibrium flows and optical diagnostics for combustion and plasmas. He received his Bachelor of Technology degree from the Indian Institute of Technology in Madras in 1976, an MS from Syracuse University in 1977, and a PhD from Stanford University in 1983 all in Mechanical Engineering. He was a post-doctoral Scholar in the Molecular Physics Laboratory at SRI International and joined UT Austin in 1983 in the department of Mechanical Engineering. He was promoted to Associate Professor in 1988 and transferred to Aerospace Engineering in 1989. He was promoted to full Professor in 1995 and has been the Director of the Center for Aeromechanics Research since 1999. He served as Chair of the Department from 2009-2012.

Among numerous awards he was Fulbright Senior Scholar in France in 1993 and was awarded the Boeing-A.D. Welliver Faculty Fellowship by the Boeing Company in 1998. He received the Lockheed Martin Aeronautics Company Award for Excellence in Engineering Teaching in Spring 2003, and was elected to the Academy of Distinguished Teachers at the University of Texas in 2005. In February 2012 he was selected Professor of the Year by the Senate of College Councils at UT Austin and was awarded The University of Texas System Regents’ Outstanding Teaching Award in August 2016.

Dr. Varghese’s research focuses on understanding the basic molecular processes occurring in high speed, high temperature, and non-equilibrium flows. This is an inter-disciplinary field, requiring a synthesis of physics and chemistry with the more traditional engineering disciplines of fluid mechanics, heat transfer, and thermodynamics. He applies his work to the study of hypersonic and rarefied flows, plasmas, and combustion. He has established a laser diagnostics laboratory for experimental studies in combustion and plasma discharges. He also has an active program in planetary scale simulations of rarefied flows and has developed a novel technique for accurate solutions of the Boltzmann equation using quasi-particle simulation. His research publications have been extensively referenced and a recent search showed over 3800 citations of his work on Google Scholar. He is co-inventor on six US patents related to applications of Raman spectroscopy.