Mechanical Engineering Commons^™

On The Application Of Mechanical Vibration In Robotics-Assisted Soft Tissue Intervention, Iman Khalaji

Electronic Thesis and Dissertation Repository

Mechanical vibration as a way of transmitting energy has been an interesting subject to study. While cyclic oscillation is usually associated with fatigue effect, and hence a detrimental factor in failure of structures and machineries, by controlled transmission of vibration, energy can be transferred from the source to the target. In this thesis, the application of such mechanical vibration in a few surgical procedures is demonstrated.

Three challenges associated with lung cancer diagnosis and treatment are chosen for this purpose, namely, Motion Compensation, tumor targeting in lung Needle Insertion and Soft Tissue Dissection:

1. A robotic solution is proposed …

Design Of A Haptic Interface For Medical Applications Using Magneto-Rheological Fluid Based Actuators, Nima Najmaei

Electronic Thesis and Dissertation Repository

This thesis reports on the design, construction, and evaluation of a prototype two degrees-of-freedom (DOF) haptic interface, which takes advantage of Magneto-Rheological Fluid (MRF) based clutches for actuation. Haptic information provides important cues in teleoperated systems and enables the user to feel the interaction with a remote or virtual environment during teleoperation. The two main objectives in designing a haptic interface are stability and transparency. Indeed, deficiencies in these factors in haptics-enabled telerobotic systems has the introduction of haptics in medical environments where safety and reliability are prime considerations. An actuator with poor dynamics, high inertia, large size, and heavy …

Induction Of Differentiation Of Dental Pulp-Derived Mesenchymal Stem Cells (Dpsc), Aubrey Young

UNLV Theses, Dissertations, Professional Papers, and Capstones

Mesenchymal stem cells are derived from a variety of human tissues and are being bioengineered and studied for possible uses in the advancement of medicine. Recent efforts are being focused on Dental Pulp Stem Cells (DPSC's) due to the accessibility of this tissue. Many factors influence DPSC quality and quantity, including the specific methods used to isolate, collect, concentrate, and store these isolates once they are removed. Ancillary factors, such as the choice of media, the selection of early versus late passage cells, and cryopreservation techniques may also influence the differentiation potential and proliferative capacity of DPSC isolates.

The objective …

Designing A Biomimetic Testing Platform For Actuators In A Series-Elastic Co-Contraction System, Ryan Tyler Schroeder

UNLV Theses, Dissertations, Professional Papers, and Capstones

Actuators determine the performance of robotic systems at the most intimate of levels. As a result, much work has been done to assess the performance of different actuator systems. However, biomimetics has not previously been utilized as a pretext for tuning a series elastic actuator system with the purpose of designing an empirical testing platform. Thus, an artificial muscle tendon system has been developed in order to assess the performance of two distinct actuator types: (1) direct current electromagnetic motors and (2) ultrasonic rotary piezoelectric motors. Because the design of the system takes advantage of biomimetic operating principles such as …

Design Of A Passive Exoskeleton Spine, Haohan Zhang

Masters Theses

In this thesis, a passive exoskeleton spine was designed and evaluated by a series of biomechanics simulations. The design objectives were to reduce the human operator’s back muscle efforts and the intervertebral reaction torques during a full range sagittal plane spine flexion/extension. The biomechanics simulations were performed using the OpenSim modeling environment. To manipulate the simulations, a full body musculoskeletal model was created based on the OpenSim gait2354 and “lumbar spine” models. To support flexion and extension of the torso a “push-pull” strategy was proposed by applying external pushing and pulling forces on different locations on the torso. The external …

Implementation And Validation Of Aortic Remodeling In Hypertensive Rats, Shijia Zhao, Linxia Gu

Department of Mechanical and Materials Engineering: Faculty Publications

A computational framework was implemented and validated to better understand the hypertensive artery remodeling in both geometric dimensions and material properties. Integrating the stress-modulated remodeling equations into commercial finite element codes allows a better control and visualization of local mechanical parameters. Both arterial thickening and stiffening effects were captured and visualized. An adaptive material remodeling strategy combined with the element birth and death techniques for the geometrical growth were implemented. The numerically predicted remodeling results in terms of the wall thickness, inner diameter, and the ratio of elastin to collagen content of the artery were compared with and fine-tuned by …

Full-Field Vibrometry By High-Speed Digital Holography For Middle-Ear Mechanics, Ivo Dobrev

Ivo Dobrev

Hearing loss affects approximately 1 in 10 people in the world and this percentage is increasing every year. Some of the most common courses for hearing loss are disorders of the human tympanic membrane (TM or eardrum) and middle-ear. Early detection and diagnosis of hearing loss as well as research and understanding of the hearing process depend on medical and research tools for quantification of the hearing capabilities, including the function of the human TM in the complex acoustic-mechanical transformation of environmental sounds into vibrations of the middle- and the inner-ear. Current ear exams are assessing the state of the …

Cfd Simulation Of The Thermal Performance Of A Parallel Counter-Parallel Flow Heat Exchanger For The Treatment Of Hypothermia, Alex Heller

UNLV Theses, Dissertations, Professional Papers, and Capstones

Hypothermia is a life-threatening condition. Currently, active warming methods are the most effective treatment for dysthermic patients. The aim of this study is to investigate the use of computational fluid dynamics (CFD) in evaluating the thermal performance of a parallel/counter-parallel flow heat exchanger used as part of a fluid warmer to treat Hypothermia. The 3D model of the heat exchanger is divided into three regions; Infusate (fluid to be heated), Hot Water (heating fluid), and a Solid Region (wall). At the end of the heat exchanger, an elbow section is used to create the counter-parallel flow arrangement specific to this …

Fluid Powered Miniature In-Vivo Robots For Minimally Invasive Surgery (Mis), Abolfazl Pourghodrat

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Minimizing the invasiveness of surgery is believed to improve patient outcomes. Bleeding, infection, and pain are major concerns in surgery afflicting patients for decades. Minimally invasive techniques have come into play to reduce these concerns and smooth the evolution of abdominal surgery to a scarless process where nearly all surgeries can be performed without a skin incision. Technology continually advances the frontier of development of novel surgical devices to implement less invasive surgical techniques.

Fusion of robotics and Minimally Invasive Surgery (MIS) has created new opportunities to develop diagnostic and therapeutic tools. Surgical robotics is advancing from externally actuated systems …

Subtalar Fusion Fixture Design And Test, Nathan Ortiz

Honors Theses

Subtalar arthrodesis is performed when cartilage in the talo-calcaneal (the ankle) joint is degraded in a patient and there are multiple approaches to this surgery. Using synthetic bone material, fixtures were cast from aluminum, using the process of evaporation pattern casting, and epoxy. This casting was used to grip the calcaneus bone of the foot in order to load it mechanically, simulating different scenarios that would be encountered during walking. The relative displacement of the ankle joint was measured using a digital image correlation (DIC) program that was modified to work in both two- and three-dimensional space. This program can …

Biomechanical Performance Of Variable And Fixed Angle Locked Volar Plates For The Dorsally Comminuted Distal Radius, Patrick Atkinson, D. Martineau, J. Shorez, C. Beran, A. G. Dass

Mechanical Engineering Publications

Background

The ideal treatment strategy for the dorsally comminuted distal radius fracture continues to evolve. Newer plate designs allow for variable axis screw placement while maintaining the advantages of locked technology. The purpose of this study is to compare the biomechanical properties of one variable axis plate with two traditional locked constructs.

Methods

Simulated fractures were created via a distal 1 cm dorsal wedge osteotomy in radius bone analogs. The analogs were of low stiffness and rigidity to create a worst-case strength condition for the subject radius plates. This fracture-gap model was fixated using one of three different locked volar …