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Knowledge Integration In Domain-Informed Machine Learning And Multi-Scale Modeling Of Nonlinear Dynamics In Complex Systems, Phat K. Huynh Oct 2023

Knowledge Integration In Domain-Informed Machine Learning And Multi-Scale Modeling Of Nonlinear Dynamics In Complex Systems, Phat K. Huynh

USF Tampa Graduate Theses and Dissertations

Nonlinear dynamical systems have been extensively used to model various phenomena in the changing world around us, especially in science and engineering fields. Thanks to breakthrough advancements in sensing technologies, an increasingly high volume of multi-modal sensor data has been collected, which enables us gain better insights into complex systems dynamics and build sophisticated data-driven machine-learning-based dynamic models without having the access to the underlying governing equations. However, integrating domain-specific knowledge in machine learning algorithms remains pivotal for various reasons: it promises enhanced predictive accuracy, better model interpretability, and increased generalizability. This dissertation delves into three core research questions, each …


Metachronal Locomotion: Swimming, Scaling, And Schooling, Kuvvat Garayev Jun 2023

Metachronal Locomotion: Swimming, Scaling, And Schooling, Kuvvat Garayev

USF Tampa Graduate Theses and Dissertations

This dissertation deals with one type of underwater locomotion called metachronal swimming in which the organism sequentially beats its multiple appendages allowing phase lag between adjacent neighbors. Metachronally swimming species are widespread and include copepods, shrimp, ctenophores, and tomopterid worms to name few. First, using the high-speed recording and planar particle image velocimetry (PIV) measurement, I report on kinematics of fast metachronal swimmer and constructive vortex interactions among its appendages and discuss its implications for improved performance regarding the swimming. Second, I show how hydrodynamic performance of all metachronal swimmers (paramecia, copepods, tomopterid worms, krill etc.) can be scaled by …


Damage Identification In 3d Printed Metal Parts Using Deep Learning, Romaine Byfield, Alireza Modir, Ibrahim Tansel, Raniero Plaza May 2023

Damage Identification In 3d Printed Metal Parts Using Deep Learning, Romaine Byfield, Alireza Modir, Ibrahim Tansel, Raniero Plaza

36th Florida Conference on Recent Advances in Robotics

An active Structural Health Monitoring (SHM) method called Surface Response to Excitation (SuRE), is used in this study to detect and quantify the damages created by a milling operation on additively manufactured metal plates. This method entails bonding two piezoelectric disks to the test specimens, one to excite it with surface waves from one end of the plate, and the other to sense the dynamic response to excitation at the other end. A sweep sine wave with a duration of 1 ms, ranging from 50-120 kHz is used as the excitation signal. Five stainless steel plates of identical size (195×54×2.5 …


Assistive Robotic Platform For Non‐Urgent Household Tasks: A New Design, Amanda Serger, Normandy Tanguilan, Hakki Erhan Sevil May 2023

Assistive Robotic Platform For Non‐Urgent Household Tasks: A New Design, Amanda Serger, Normandy Tanguilan, Hakki Erhan Sevil

36th Florida Conference on Recent Advances in Robotics

Humans overcome minor household inconveniences daily without fully recognizing how challenging these tasks could be for individuals such as elderly people or people with disabilities. Those people often times struggle to complete tasks, for instance opening a door or reaching for an item, leading them to rely on caregivers for help. During the COVID-19 pandemic, this caregiver support becomes an unsafe and unreliable solution that can result in a greater risk, thus the need for another solution arises: robotic technology. Recent developments in the robotics field have paved the way for this research, aiming to design a home assistance robot …


Comparing Probabilistic Planning Success On Three Types Of Robots: Wheeled, Legged, And Underwater, Daniel Griessler, Josias Moukpe, Braidan Duffy, Akil Hosang, Blake Janes, Omar Jebari, Kourtnee Fernalld, Erbene De Castro, Humberto Rivera, William Stern, Badria Alfurhood, Akram Alghanmi, Marius Silaghi May 2023

Comparing Probabilistic Planning Success On Three Types Of Robots: Wheeled, Legged, And Underwater, Daniel Griessler, Josias Moukpe, Braidan Duffy, Akil Hosang, Blake Janes, Omar Jebari, Kourtnee Fernalld, Erbene De Castro, Humberto Rivera, William Stern, Badria Alfurhood, Akram Alghanmi, Marius Silaghi

36th Florida Conference on Recent Advances in Robotics

We compare the relevance of POMDP graphical models to addressing a given common task, the autonomous navigation, in mobile robotics, for robots in three different environments: legged walking, wheeled, and underwater robots. Principled approaches to the implementation of Intelligent robots in realistic environments with uncertainty exploit probabilistic models. The use of graphical models increases tractability and verifiability of probabilistic reasoning. Our robots face similar localization problems of passing by three doors on a corridor in a building, respectively, for the underwater case, of passing by three barrels in a pool. All the three robots are equipped solely with noisy sonars …


Flexible Magnetic Skin Sensor Array For Torsion Perception, Lucja Stawikowska, Erik D. Engeberg May 2023

Flexible Magnetic Skin Sensor Array For Torsion Perception, Lucja Stawikowska, Erik D. Engeberg

36th Florida Conference on Recent Advances in Robotics

Prosthetic hands help upper limb amputees and people who were born without hands. Currently, these prostheses are rather rudimentary and do not provide adequate sensing capabilities compared to a human hand. People use their natural hands to perceive complex tactile phenomena such as shear and torsion using thousands of mechanoreceptors in their fingertips. The capability to detect torsional loads at the fingertips is a notable gap in prosthetic hand sensation. Flexible tactile sensors are a promising new technology that would be ideal for prosthetic hands since they allow for stretching and movement like human skin without damage to the sensor. …


Health Effects Of Oil Spills And Dispersal Of Oil Droplets And Zooplankton By Langmuir Cells, Sanjib Gurung Nov 2022

Health Effects Of Oil Spills And Dispersal Of Oil Droplets And Zooplankton By Langmuir Cells, Sanjib Gurung

USF Tampa Graduate Theses and Dissertations

This Ph.D. dissertation deals with the study of the health effects of crude oil vapors from oil spills, the effect of Langmuir circulation on the dispersion of oil droplets during oil spill events, and the biological significance of Langmuir circulation. The introduction to areas of three major research projects undertaken during my Ph.D. is included in chapter 1 and the relevant literature review is included in chapter 2. The first research project described in chapter 3 involves the quantification of health effects on embryonic Gulf killifish due to exposure to crude oil vapors. The second research project described in chapter …


Passive Radiative Cooling By Spectrally Selective Nanoparticles In Thick Film Nanocomposites, David Allen Young Jun 2022

Passive Radiative Cooling By Spectrally Selective Nanoparticles In Thick Film Nanocomposites, David Allen Young

USF Tampa Graduate Theses and Dissertations

Passive cooling of buildings is a benefit to society since no energy input is required for space cooling which reduces electricity consumption, fossil fuel burning, and greenhouse gas emissions. When a passive cooling technology radiates heat from the earth through the atmospheric windows to space higher levels of cooling power are possible -- this phenomenon is classified as passive “radiative” cooling. Spectrally selective surface coatings provide radiative cooling to lower surface temperatures by reflecting most solar radiation, while emitting infrared radiation at wavelengths between 8-13 μm through the primary atmospheric window to the cold of space. Multiple applications of radiative …


Hybrid Rans-Les Hemolytic Power Law Modeling Of The Fda Blood Pump, Joseph Tarriela Jun 2022

Hybrid Rans-Les Hemolytic Power Law Modeling Of The Fda Blood Pump, Joseph Tarriela

USF Tampa Graduate Theses and Dissertations

This study applies the SBES and IDDES hybrid RANS-LES turbulence models along with the K-ω SST model to four flow conditions of the FDA blood pump. Validation of all three turbulence models show good agreement with experimental pressure and velocity fields. Evaluation of turbulent kinetic energy fields for the hybrid models show 80-90+% of kinetic energy is resolved in the rotor and diffuser regions of the pump. Hemolysis power law models were evaluated using the commonly used von Mises stress and additional energy dissipation stress (EDS). Results show viscous and Reynolds stresses computed with the K-ω SST under predict and …


Estimating The As-Placed Grout Volume Of Auger Cast Piles, Tristen Mee Mar 2022

Estimating The As-Placed Grout Volume Of Auger Cast Piles, Tristen Mee

USF Tampa Graduate Theses and Dissertations

Augered Cast-in-Place (ACIP) piles are a geotechnical foundation element increasingly used to support large publicly funded structures as an alternative to drilled shafts or driven piles. ACIP piles are constructed by drilling an excavation to the full length of the designed pile with a continuous flight auger. Grout (cement, sand, and water mixture) is then pumped through the hollow auger stem to begin grouting the excavation. After establishing an initial head pressure, the auger is slowly extracted while the remainder of the pile is grouted. Once the auger is completely removed, the steel reinforcement cage is lowered into the grouted …


Modeling The Ambient Conditions Of A Manufacturing Environment Using Computational Fluid Dynamics (Cfd), Yang Liu Oct 2021

Modeling The Ambient Conditions Of A Manufacturing Environment Using Computational Fluid Dynamics (Cfd), Yang Liu

USF Tampa Graduate Theses and Dissertations

As manufacturing equipment evolve to higher speed and require high precision operations, the impact of environmental changes on machine accuracy becomes critical. Due to thermal expansion, the structure of the machine can change when ambient temperature varies. When the airflow in the laboratory changes, this also alters the operator's thermal comfort. Either the change in machine structure or operator comfort can ultimately affect machine accuracy. The manufacturing industry is currently using heating, ventilation, and air-conditioning (HVAC) systems to regulate the temperature of the working environment. However, since conventional HVAC systems determine whether to activate the HVAC system by collecting the …


Event-Triggered Control Architectures For Scheduling Information Exchange In Uncertain And Multiagent Systems, Stefan Ristevski Jul 2021

Event-Triggered Control Architectures For Scheduling Information Exchange In Uncertain And Multiagent Systems, Stefan Ristevski

USF Tampa Graduate Theses and Dissertations

Despite the numerous advantages that networked controlled systems provide, potential network overload in these systems can severely degrade their performance and even cause catastrophic failures. To this end, the work presented in this dissertation provides a neat solution on reducing network utilization in uncertain networked controlled systems using an adaptive event-triggered control approach predicated on a novel dynamical threshold and information exchange methodology while guaranteeing closed-loop system stability.

In particular, consider a system consisting of an operator (e.g, a ground station) and an uncertain controlled dynamical system (e.g., a vehicle equipped with feedback control algorithm), where the aim of the …


Interrelation Of Thermal Stimulation With Haptic Perception, Emotion, And Memory, Mehdi Hojatmadani Jul 2021

Interrelation Of Thermal Stimulation With Haptic Perception, Emotion, And Memory, Mehdi Hojatmadani

USF Tampa Graduate Theses and Dissertations

Haptics is an interdisciplinary field of science that deals with how humans perceive and respond to different sensory cues perceived through touch. Thermal haptics as a branch deals with how humans perceive the temperature sensation and respond to that. The process in which thermal perception occurs is well known to researchers. What seems missing in the literature is how temperature interacts or sometimes intervenes in other physiological and psychological aspects of our lives. In this research, a series of studies are presented where the main focus was how temperature and brain interact with each other to impede or enhance our …


A Framework To Aid Decision Making For Smart Manufacturing Technologies In Small-And Medium-Sized Enterprises, Purvee Bhatia Jun 2021

A Framework To Aid Decision Making For Smart Manufacturing Technologies In Small-And Medium-Sized Enterprises, Purvee Bhatia

USF Tampa Graduate Theses and Dissertations

The fourth industrial revolution or Industry 4.0 has changed today’s manufacturing scenario. The transition to smart manufacturing technologies has been evolving over the last few years and has recently accelerated due to the pandemic. The need to make manufacturing systems agile, adaptive, resilient, and robust has expediated the adoption and implementation of smart manufacturing technologies.

Despite the interest of manufacturers in smart manufacturing, the adoption rate has been slow due to the lack of decision-making tools that can provide a clear strategic roadmap for effective execution. Small and medium sized enterprises (SMEs) are especially slow in adoption due to the …


Sensible/Latent Hybrid Thermal Energy Storage For The Supercritical Carbon Dioxide Brayton Cycle, Kelly Osterman Apr 2021

Sensible/Latent Hybrid Thermal Energy Storage For The Supercritical Carbon Dioxide Brayton Cycle, Kelly Osterman

USF Tampa Graduate Theses and Dissertations

Mitigating the effects of climate change will require rapid deployment of a carbon-free electricity system that includes all available forms of zero-carbon energy. Both renewables and nuclear show great promise, but both come with drawbacks. Power production from wind and solar is limited to times when their respective resources are available, while nuclear is limited in its ability to adjust its output according to the ever-varying demand for electricity. Additionally, the systems must be affordable. One way to reduce the cost of thermal power plants (concentrated solar power and nuclear) is to use new power cycles, such as the supercritical …


Dynamic Loading Directed Neural Stem Cell Differentiation, Abdullah Revaha Akdemir Apr 2021

Dynamic Loading Directed Neural Stem Cell Differentiation, Abdullah Revaha Akdemir

USF Tampa Graduate Theses and Dissertations

Spinal cord injuries (SCI) are among the biggest challenges for medical and engineering fields in the modern era. Many people experience various accidents every year that cause major irreversible trauma in the spinal cord. Damaged neural cells caused by SCI cannot be regenerated, and patients have to live with pain, spasms, or loss of movement. Stem cell differentiation can be a potential solution to generate enough neurol cells in vitro to apply at the defective region. In this research, the impact of dynamic mechanical stimulation on the differentiation of PC-12 cell lines towards neurol cells was studied. Models to apply …


Evaluating The Performance Of Devices Engineering To Quantify The Fars Test, Harsh Patel Mar 2021

Evaluating The Performance Of Devices Engineering To Quantify The Fars Test, Harsh Patel

USF Tampa Graduate Theses and Dissertations

Clinical rating scales play a major role in assessing progressive neurological diseases. Neurologists use these rating scales to provide a better diagnosis, to provide a better treatment plan, and to analyze the outcome of clinical trials. Friedreich’s ataxia (FA) is a neurodegenerative disease that causes ataxia in limbs, speech impairment, and polyneuropathy. Since FA is a progressive disease, various rating scales have been standardized to provide an objective assessment of the patient’s current condition. The Friedreich Ataxia Rating Scale (FARS) includes several tests to capture neurological features of FA and to assess the functional stage of ataxia. The rubrics used …


Experimental Investigation Of Liquid Height Estimation And Simulation Verification Of Bolt Tension Quantification Using Surface Acoustic Waves, Hani Alhazmi Nov 2020

Experimental Investigation Of Liquid Height Estimation And Simulation Verification Of Bolt Tension Quantification Using Surface Acoustic Waves, Hani Alhazmi

USF Tampa Graduate Theses and Dissertations

In this dissertation, two separate applications that are related to surface acoustic waves in a solid media are presented. The first study concerns simulating and validating an experimentally study for quantifying the bolt tension in the bolted joints using the surface acoustic wave. The second study experimentally investigates measuring the level of a liquid existing on a solid surface via surface acoustic waves and exploring the effect of liquid existence on the propagation of surface acoustic waves over the solid surface.

Quantifying bolt tension and ensuring that bolts are appropriately tightened for large-scale civil infrastructures are crucial. This study investigates …


Roboat - Rescue Operations Bot Operating In All Terrains, Akshay Gulhane Oct 2020

Roboat - Rescue Operations Bot Operating In All Terrains, Akshay Gulhane

USF Tampa Graduate Theses and Dissertations

Natural calamities are on a rise with each passing year. Disasters like floods and fire take many lives all around the world, especially in remote areas or less developed countries. One such incident was the Kerala Floods in India where rescue services had difficulty reaching to all the people on time since a huge landmass (more than 9 districts) was flooded and hence villagers or other people risked their lives to save others in danger without proper safety equipment. Amazon Rainforest Fires was another example for a major destruction of an ecosystem. The main reason for lack of facilities in …


Control Of A Human Arm Robotic Unit Using Augmented Reality And Optimized Kinematics, Carlo Canezo Oct 2020

Control Of A Human Arm Robotic Unit Using Augmented Reality And Optimized Kinematics, Carlo Canezo

USF Tampa Graduate Theses and Dissertations

There are more than 350000 amputees in the US who suffer loss of functionality in their daily living activities, and roughly 100000 of them are upper arm amputees. Many of these amputees use prostheses to compensate part of their lost arm function, including power prostheses. Research on 6-7 degree of freedom powered prostheses is still relatively new, and most commercially available powered prostheses are typically limited to 1 to 3 degrees of freedom. Due to the myriad of possible options for various powered protheses from different manufacturers, each configuration is governed by a distinct control scheme typically specific to the …


Swimming Of Pelagic Snails: Kinematics And Fluid Dynamics, Ferhat Karakas Oct 2020

Swimming Of Pelagic Snails: Kinematics And Fluid Dynamics, Ferhat Karakas

USF Tampa Graduate Theses and Dissertations

Pteropods (also known as sea butterflies or sea angels), are holoplanktonic marine snails which swim by flapping a pair of extremely flexible wings. The wings are modified from the molluscan foot and the wing motions are supported by the fluid pressure without any rigid support. Sea angels (gymnosome pteropods) are completely naked; in contrast, sea butterflies (thecosome pteropods) have negatively buoyant aragonite shells which vary in geometry and size among different species. Pteropods are seasonally abundant in the ocean, and an important food source for the other zooplanktons, fishes, and whales. Though studies have been conducted regarding their biology, ecology, …


Simulation And Verification Of Phase Change Materials For Thermal Energy Storage, Marwan Mosubah Belaed Apr 2020

Simulation And Verification Of Phase Change Materials For Thermal Energy Storage, Marwan Mosubah Belaed

USF Tampa Graduate Theses and Dissertations

Greenhouse gas (GHG) emissions have a global impact on world economies and the ecosystem. Scientific assessment of GHG emissions is an issue that requires immediate action from key decision-makers and influencers. A comprehensive review of the impact of climate change and its dire consequences on daily life is illustrated in this dissertation. The most common technique to lower GHG emissions in the atmosphere is by switching GHG emission sources to zero-emission sources such as solar energy, wind energy, bioenergy, and geothermal power. Recently, all these technologies have made significant progress in lowering capital operation costs and their cycle efficiencies. This …


Investigation Of Navigation Systems For Size, Cost, And Mass Constrained Satellites, Omar Awad Apr 2020

Investigation Of Navigation Systems For Size, Cost, And Mass Constrained Satellites, Omar Awad

USF Tampa Graduate Theses and Dissertations

The feasibility of using radically inexpensive micro-electromechanical system (MEMS) technology for navigation of a nanosatellite is investigated with a focus on attitude estimation. Typically, larger satellites are equipped with star cameras, sun sensors, or Earth horizon sensors for attitude estimation. These sensors can provide very accurate attitude measurements. A nanosatellite is highly size, power, and cost constrained and cannot readily accommodate these sensors. Our mission is to design, build, and operate a radically inexpensive nanosatellite system. While there is no consensus on what constitutes a "radically inexpensive" satellite, our goal is a maximum cost of $10,000 per unit. This precludes …


Laser Micropatterning Effects On Corrosion Resistance Of Pure Magnesium Surfaces, Yahya Efe Yayoglu Apr 2020

Laser Micropatterning Effects On Corrosion Resistance Of Pure Magnesium Surfaces, Yahya Efe Yayoglu

USF Tampa Graduate Theses and Dissertations

Magnesium and its alloys are good candidates to manufacture medical implants. They have excellent biocompatibility and because they biodegrade secondary surgical operation to remove the implant could be eliminated. However, in aqueous environments, magnesium alloys rapidly corrode, resulting in premature degradation of the implant along with biologically intolerable hydrogen gas generation. In literature, there are multiple studies focused on creating water repelling hydrophobic magnesium surfaces in order to decrease corrosion rates. Hydrophobic properties can be achieved by creation of a roughness profile on an initially smooth surface combined with a treatment that reduces the free surface energy. In theory, hydrophobic …


Manipulation And Patterning Of Mammalian Cells Using Vibrations And Acoustic Forces, Joel Cooper Apr 2020

Manipulation And Patterning Of Mammalian Cells Using Vibrations And Acoustic Forces, Joel Cooper

USF Tampa Graduate Theses and Dissertations

Recently, there has been a surge in researchers and scientists investigating different methods which move, manipulate, and pattern biological cells. Multiple different mechanisms can be used for cellular manipulation, microfluidics, biochemical queues, and even optics, just to name a few. However, all techniques have their downsides. A majority of these methods require expensive equipment or reagents and can only manipulate a small number of cells at a time.

Some of the most common cell manipulation devices utilize acoustic pressure waves to move the cells to desired locations. Currently, it is unknown what level of force from these types of devices …


Stable Adaptive Control Systems In The Presence Of Unmodeled And Actuator Dynamics, Kadriye Merve Dogan Feb 2020

Stable Adaptive Control Systems In The Presence Of Unmodeled And Actuator Dynamics, Kadriye Merve Dogan

USF Tampa Graduate Theses and Dissertations

In adaptive control of physical systems, it is well-known that the presence of actuator and/or unmodeled dynamics in feedback loops can yield to unstable closed-loop system trajectories. Motivated by this standpoint, this dissertation presents novel model reference and distributed adaptive control architectures with stability and performance guarantees for uncertain sole and multiagent dynamical systems with unmodeled and/or actuator dynamics.

Specifically, model reference and distributed adaptive control architectures are powerful theoretical tools for both sole and multiagent systems, where they have the capability to suppress the effect of exogenous disturbances and system uncertainties for achieving a desired level of closed-loop system …


Shallow Water Seafloor Geodesy: Gps On An Anchored Spar Buoy, Surui Xie Feb 2020

Shallow Water Seafloor Geodesy: Gps On An Anchored Spar Buoy, Surui Xie

USF Tampa Graduate Theses and Dissertations

Measuring seafloor motion in shallow coastal water is challenging due to strong and highly variable oceanographic effects. Such measurements are potentially useful for monitoring near-shore coastal subsidence, subsidence due to petroleum withdrawal, strain accumulation/release processes in marine shelves and submerged volcanoes, and certain fresh water applications, such as volcano deformation in caldera-hosted lakes. I participated in a project to develop a seafloor geodetic system for this environment based on an anchored spar buoy topped by high precision GPS. Orientation of the buoy is measured using a digital compass that provides heading, pitch, and roll information. The combined orientation and GPS …


Human-Skin-Inspired Adaptive Smart Textiles Capable Of Amplified Latent Heat Transfer For Thermal Comfort, Gunwoo Kim, Calvin Gardner, Kyuin Park, Ying Zhong, Sungho Jin Jan 2020

Human-Skin-Inspired Adaptive Smart Textiles Capable Of Amplified Latent Heat Transfer For Thermal Comfort, Gunwoo Kim, Calvin Gardner, Kyuin Park, Ying Zhong, Sungho Jin

Mechanical Engineering Faculty Publications

Thermally adaptive textiles (TATs) enable human subjects to attain thermal comfort without energy consumption, which can lead to enormous energy savings on heating, ventilation, and air conditioning (HVAC) in buildings. Herein, TAT structures which respond to the sweat and generate pores by opening an array of flap-shaped pores patterned on the fabric surface are proposed. A moisture-driven self-actuator for flap opening by constructing a bilayer consisting of a hygroscopic layer using polyethylene glycol and cellulose acetate, and a hydrophobic polymer using a polyester type polymer, is used and successfully demonstrated an essentially instant 4 °C apparent temperature cooling performance within …


Collagen Production And Niche Engineering: A Novel Strategy For Cancer Cells To Survive Acidosis In Dcis And Evolve, Mehdi Damaghi, Hidetoshi Mori, Samantha Byrne, Liping Xu, Tingan Chen, Joseph Johnson, Nathan D. Gallant, Andriy Marusyk, Alexander D. Borowsky, Robert J. Gillies Jan 2020

Collagen Production And Niche Engineering: A Novel Strategy For Cancer Cells To Survive Acidosis In Dcis And Evolve, Mehdi Damaghi, Hidetoshi Mori, Samantha Byrne, Liping Xu, Tingan Chen, Joseph Johnson, Nathan D. Gallant, Andriy Marusyk, Alexander D. Borowsky, Robert J. Gillies

Mechanical Engineering Faculty Publications

Growing tumors are dynamic and nonlinear ecosystems, wherein cancer cells adapt to their local microenvironment, and these adaptations further modify the environment, inducing more changes. From nascent intraductal neoplasms to disseminated metastatic disease, several levels of evolutionary adaptations and selections occur. Here, we focus on one example of such an adaptation mechanism, namely, “niche construction” promoted by adaptation to acidosis, which is a metabolic adaptation to the early harsh environment in intraductal neoplasms. The avascular characteristics of ductal carcinoma in situ (DCIS) make the periluminal volume profoundly acidic, and cancer cells must adapt to this to survive. Based on discovery …


Spontaneous Formation Of Sub-4 Nm Nanocrystalline Alloy Via Polymorphic Phase Transformation, Ying Zhong, Chunqing Wang, Jin Wang, Huiwen Ma, Sriram Krishnamoorthy, Vladislav Paley, Zijian Weng, Sungho Jin Jan 2020

Spontaneous Formation Of Sub-4 Nm Nanocrystalline Alloy Via Polymorphic Phase Transformation, Ying Zhong, Chunqing Wang, Jin Wang, Huiwen Ma, Sriram Krishnamoorthy, Vladislav Paley, Zijian Weng, Sungho Jin

Mechanical Engineering Faculty Publications

A new phase-transformation-induced path to spontaneous formation of extreme nanograin structure is reported. In-situ-heating-mode-microscopy exhibited a substantial grain-growth of Cu6Sn5. During cooling, the grain-growth continued, but it spontaneously switched to grain-refinement mode on phase transformation through ∼180 °C from η-Cu6Sn5 to η’-Cu6Sn5, ending up with an extremely small nanograin size of ∼2.5 nm. The cooling cycling always restores the nanograin size regardless of thermal exposure history, making this to be the first demonstration to stabilize the nanograin with its own spontaneous behavior. The Young’s Modulus was significantly reduced by ∼×3, and the elongation was remarkably increased by …