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Full-Text Articles in Biomedical Engineering and Bioengineering

A Framework For Stable Robot-Environment Interaction Based On The Generalized Scattering Transformation, Kanstantsin Pachkouski Nov 2022

A Framework For Stable Robot-Environment Interaction Based On The Generalized Scattering Transformation, Kanstantsin Pachkouski

Electronic Thesis and Dissertation Repository

This thesis deals with development and experimental evaluation of control algorithms for stabilization of robot-environment interaction based on the conic systems formalism and scattering transformation techniques. A framework for stable robot-environment interaction is presented and evaluated on a real physical system. The proposed algorithm fundamentally generalizes the conventional passivity-based approaches to the coupled stability problem. In particular, it allows for stabilization of not necessarily passive robot-environment interaction. The framework is based on the recently developed non-planar conic systems formalism and generalized scattering-based stabilization methods. A comprehensive theoretical background on the scattering transformation techniques, planar and non-planar conic systems is presented. …


Motion And Crosslinked Polyethylene Wear In Reverse Total Shoulder Arthroplasty, Christopher Millward Jul 2022

Motion And Crosslinked Polyethylene Wear In Reverse Total Shoulder Arthroplasty, Christopher Millward

Electronic Thesis and Dissertation Repository

The reverse total shoulder arthroplasty (RTSA) has quickly grown to become the most commonly used shoulder arthroplasty design; however, reports have shown evidence of RTSA failures related to polyethylene wear and damage. Therefore, the present work investigated the wear of crosslinked polyethylene (XLPE) in environments similar to that of an in vivo RTSA. Additionally, a computational model was developed based on a previous study of the shoulder motions obtained from a selection of typical patients with RTSA. This model quantified the amount of glenohumeral motion that an RTSA may be subjected to in vivo and provided an approximate value for …


The Effects Of A Porous Internal Lattice Design On The Articular Contact Mechanics Of Radial Head Hemiarthroplasty Implants, Jessica Benitah Mar 2022

The Effects Of A Porous Internal Lattice Design On The Articular Contact Mechanics Of Radial Head Hemiarthroplasty Implants, Jessica Benitah

Electronic Thesis and Dissertation Repository

Hemiarthroplasty, where one side of a joint is replaced, is a minimally invasive procedure. It allows for the preservation of native tissue, though a significant ramification is accelerated cartilage wear when articulating with high stiffness materials that do not mimic the mechanical stiffness of the native tissue. An implant that employs a lattice design can significantly lower the stiffness of a solid structure whilst maintaining strength. This study was conducted to investigate the effect of implementing a porous internal lattice structure with a thin outer shell on the articular contact mechanics, using a radial head hemiarthroplasty. It was hypothesized that …


The Role Of Transient Vibration Of The Skull On Concussion, Rodrigo Dalvit Carvalho Da Silva Mar 2022

The Role Of Transient Vibration Of The Skull On Concussion, Rodrigo Dalvit Carvalho Da Silva

Electronic Thesis and Dissertation Repository

Concussion is a traumatic brain injury usually caused by a direct or indirect blow to the head that affects brain function. The maximum mechanical impedance of the brain tissue occurs at 450±50 Hz and may be affected by the skull resonant frequencies. After an impact to the head, vibration resonance of the skull damages the underlying cortex. The skull deforms and vibrates, like a bell for 3 to 5 milliseconds, bruising the cortex. Furthermore, the deceleration forces the frontal and temporal cortex against the skull, eliminating a layer of cerebrospinal fluid. When the skull vibrates, the force spreads directly to …