Engineering Commons^™

Microparticle Propulsion For In Vivo Navigation, Louis Rogowski

Mechanical Engineering Research Theses and Dissertations

Microscale propulsion impacts a diverse array of fields, with simplistic microrobots allowing for novel innovations in microscale surgery and drug delivery. Propulsion at the microscale is constrained by physics, with time-reversal and geometric symmetries limiting available propulsion mechanisms. However, certain fluid environments and surface coatings allow for the propulsion of microparticles through externally applied magnetic fields. Presented here is a detailed analysis of microparticles propelling using spontaneous symmetry breaking, flagella surface coatings, and multi-modal actuation mechanisms. Spontaneous symmetry breaking in nonlinearly viscoelastic fluids is presented for the first time in literature, with two equal and opposite propulsion states existing along …

Detection Of Nucleotides In Hydrated Ssdna Via 2-D H-Bn Nanopore With Ionic-Liquid/Salt-Water Interface, Jungsoo Lee

Multidisciplinary Studies Theses and Dissertations

Accomplishing slow translocation speed with high sensitivity has been the greatest mission for solid-state nanopore (SSN) to electrically detect nucleobases in single-stranded DNA (ssDNA). In this study, a method to detect nucleobases in ssDNA using a SSN is introduced by considerably slowing down the translocation speed and effectively increasing its sensitivity. The ultra-thin titanium dioxide (TiO₂) coated hexagonal boron nitride (h-BN) nanopore was fabricated, along with an ionic-liquid [bmim][PF₆]/2.0 M KCl aqueous (cis/trans) interfacial system, to increase both the spatial and the temporal resolutions. As the ssDNA molecules entered the nanopore, a …

Advanced Thermal Characterization And Temperature Control To Enable The Next Generation Of Micro-Electronic Technologies, Assaad El Helou

Mechanical Engineering Research Theses and Dissertations

In the electronics world, self-heating is an inevitable by-product of electrical activation that has a major impact on device performance and reliability. Thermal technologies have been in constant development to effectively dissipate the generated heat and keep device operation temperatures within reliable limits. Moreover, thermal characterization technologies have been implemented to understand the thermal performance within microelectronic sys- tems, but not without facing experimental and numerical challenges. This work presents ad- vanced thermal investigations, both experimental and numerical, that are adapted and most suited for emerging micro-electronic technologies. Initially, the main experimental and numerical modeling challenges faced in the thermal …

Modeling, Simulation, And Testing Of Sweeping Convection, Amir Kiaee

Mechanical Engineering Research Theses and Dissertations

In this study, the new convection heat transfer concept of sweeping convection, using large particles flowing with a fluid in a channel, is considered. This novel concept is inspired by the gas exchange process in alveolar capillaries, where red blood cells (RBCs) flow with blood plasma, yielding very high gas transfer efficiency. An important characteristic of alveolar capillary blood flow, believed to be related to the high efficiency of the lungs, is the snug fitting of the RBCs into the capillaries. This tight fitting sets the RBCs (particles) acting like pistons as they flow downstream with the plasma (fluid), facilitating …

Homogenization Of Composite And Cellular Materials Incorporating Microstructure And Surface Energy Effects, Ahmad Gad

Mechanical Engineering Research Theses and Dissertations

In the last few decades, the popularity of composite and cellular materials has rapidly increased through their widespread applications in multiple engineering fields including aerospace, automotive, civil and biomedical. However, to a large extent, the success of their practical applications depends on our ability to predict their mechanical behavior by using high-fidelity mechanics models.

Micromechanical modeling of composite and cellular materials is a challenging task due to the heterogeneous nature of such materials and the interactions among various constituent phases at the microscopic level, which result in non-homogeneous deformation, strain and stress fields. Therefore, it is necessary to develop simple …

Wireless Wearable System For The Assessment Of Gait, Abdallah Jabr

Mechanical Engineering Research Theses and Dissertations

This work investigates the development and use of a wireless wearable system for the assessment of gait. The system proposed consists of a sensor module that is attached to the foot. The sensor proposed is an inertial measurement unit, often abbreviated as IMU - a 9-axis System in Package (SiP) including a 3-axis accelerometer, a 3-axis gyroscope, and a 3-axis magnetometer, as well as a fusion engine for signal processing. While the focus of this work is on evaluating gait metrics, the performance of the proposed IMU in evaluating orientation is quantified. In doing this work, we try to address …

Application Of Optimal Switching Using Adaptive Dynamic Programming In Power Electronics, Ataollah Gogani Khiabani

Mechanical Engineering Research Theses and Dissertations

In this dissertation, optimal switching in switched systems using adaptive dynamic programming (ADP) is presented. Two applications in power electronics, namely single-phase inverter control and permanent magnet synchronous motor (PMSM) control are studied using ADP. In both applications, the objective of the control problem is to design an optimal switching controller, which is also relatively robust to parameter uncertainties and disturbances in the system. An inverter is used to convert the direct current (DC) voltage to an alternating current (AC) voltage. The control scheme of the single-phase inverter uses a single function approximator, called critic, to evaluate the optimal cost …

Control And Locomotion Of Inertially And Magnetically Actuated Multi-Scale Robotic Systems, Ehab Al Khatib

Mechanical Engineering Research Theses and Dissertations

In this research, two actuation systems were introduced, inertial and magnetic actuation. In the inertial actuation, the robot used the transfer of momentum to navigate, and this momentum could be generated by spinning masses and wheels. Recent studies in our System Laboratory proved that a wide range of inertially actuated locomotion systems could be generated. This can be achieved by using a family tree approach, starting from a very simple system, and progressively evolving it to more complex ones. The motion diversity of these robots inspired us to extend their locomotion from a macro scale to millimeter and micro scales. …

Critical Point Identification In 3d Velocity Fields, Mohammadreza Zharfa

Mechanical Engineering Research Theses and Dissertations

Classification of flow fields involving strong vortices such as those from bluff body wakes and animal locomotion can provide important insight to their hydrodynamic behavior. Previous work has successfully classified 2D flow fields based on critical points of the velocity field and the structure of an associated weighted graph using the critical points as vertices. The present work focuses on extension of this approach to 3D flows. To this end, we have used the Gauss-Bonnet theorem to find critical points and their indices in the 3D velocity vector field, which functions similarly to the Poincare-Bendixon theorem in 2D flow fields. …