Biomedical Engineering and Bioengineering Commons^™

Computational Sensitivity Investigation Of Hydrogel Injection Characteristics For Myocardial Support, Hua Wang, Christopher B. Rodell, Madonna E. Lee, Neville N. Dusaj, Joseph H. Gorman Iii, Jason A. Burdick, Robert C. Gorman, Jonathan F. Wenk

Mechanical Engineering Faculty Publications

Biomaterial injection is a potential new therapy for augmenting ventricular mechanics after myocardial infarction (MI). Recent in vivo studies have demonstrated that hydrogel injections can mitigate the adverse remodeling due to MI. More importantly, the material properties of these injections influence the efficacy of the therapy. The goal of the current study is to explore the interrelated effects of injection stiffness and injection volume on diastolic ventricular wall stress and thickness. To achieve this, finite element models were constructed with different hydrogel injection volumes (150 µL and 300 µL), where the modulus was assessed over a range of 0.1 kPa …

Optical Properties Of Organic Carbon And Soot Produced In An Inverse Diffusion Flame, C. Russo, B. Apicella, J. S. Lighty, A. Ciajolo, A. Tregrossi

Mechanical and Biomedical Engineering Faculty Publications and Presentations

The carbonaceous matter (soot plus organic carbon) sampled downstream of an ethylene inverse diffusion flame (IDF) was chemically and spectroscopically analyzed in detail. In particular, the H/C ratio, the UV-Visible absorption coefficient and Raman parameters were measured and found to be representative of a highly disordered sp² -rich carbon as the early soot sampled in a premixed flame. In contrast, the optical band gap was found to be relatively low (0.7eV), closer to the optical band gap of graphite than to that of medium-sized polycyclic aromatic hydrocarbons (>2eV) which are widely considered to be soot precursors and are …

Direct Numerical Simulation Of Turbulent Katabatic Slope Flows With An Immersed-Boundary Method, Clancy Umphrey, Ray Deleon, Inanc Senocak

Mechanical and Biomedical Engineering Faculty Publications and Presentations

We investigate a Cartesian-mesh immersed-boundary formulation within an incompressible flow solver to simulate laminar and turbulent katabatic slope flows. As a proof-of-concept study, we consider four different immersed-boundary reconstruction schemes for imposing a Neumann-type boundary condition on the buoyancy field. Prandtl’s laminar solution is used to demonstrate the second-order accuracy of the numerical solutions globally. Direct numerical simulation of a turbulent katabatic flow is then performed to investigate the applicability of the proposed schemes in the turbulent regime by analyzing both first- and second-order statistics of turbulence. First-order statistics show that turbulent katabatic flow simulations are noticeably sensitive to the …

High Resolution Imaging Of The Mitral Valve In The Natural State With 7 Tesla Mri, Sam E. Stephens, Serguei Liachenko, Neil B. Ingels, Jonathan F. Wenk, Morten O. Jensen

Mechanical Engineering Faculty Publications

Imaging techniques of the mitral valve have improved tremendously during the last decade, but challenges persist. The delicate changes in annulus shape and papillary muscle position throughout the cardiac cycle have significant impact on the stress distribution in the leaflets and chords, thus preservation of anatomically accurate positioning is critical. The aim of this study was to develop an in vitro method and apparatus for obtaining high-resolution 3D MRI images of porcine mitral valves in both the diastolic and systolic configurations with physiologically appropriate annular shape, papillary muscle positions and orientations, specific to the heart from which the valve was …

The Influence Of The Electrode Dimension On The Detection Sensitivity Of Electric Cell–Substrate Impedance Sensing (Ecis) And Its Mathematical Modeling, Xudong Zhang, William Wang, Anis Nurashikin Nordin, Fang Li, Sunghoon Jang, Ioana Voiculescu

Publications and Research

Detection sensitivity is a crucial criterion in the design and application of ECIS sensors. The influence of sensing electrode dimension on detection sensitivity is investigated in this paper. Eight types of ECIS sensors were fabricated, and their experimental results reveal that smaller-radius working electrodes generate more sensitive impedance shift to cell density change. Also, the smaller radius of working electrodes yield higher impedance values, which improves signal-to-noise ratio. In a range from 1.0 mm to 3.5 mm, the distance between the working and counter electrodes does not affect impedance measurements. However, the distance should be large enough to prevent the …

Dynamic Rating Of Overhead Transmission Lines Over Complex Terrain Using A Large-Eddy Simulation Paradigm, Tyler Phillips, Ray Deleon, Inanc Senocak

Mechanical and Biomedical Engineering Faculty Publications and Presentations

Dynamic Line Rating (DLR) enables rating of power line conductors using real-time weather conditions. Conductors are typically operated based on a conservative static rating that assumes worst case weather conditions to avoid line sagging to unsafe levels. Static ratings can cause unnecessary congestion on transmission lines. To address this potential issue, a simulation-based dynamic line rating approach is applied to an area with moderately complex terrain. A micro-scale wind solver — accelerated on multiple graphics processing units (GPUs) — is deployed to compute wind speed and direction in the vicinity of powerlines. The wind solver adopts the large-eddy simulation technique …

A Wood-Powered Lawn Mower: Separating The Rules Of Thumb From Engineering Design, William White

Mahurin Honors College Capstone Experience/Thesis Projects

Biomass gasification, the thermal process of exracting combustible gasses from organic matter, is an established procedure that has been used for many years to provide fuel in various applications. It is a potential source of renewable fuel and has proven useful as a crisis energy source. This thesis investigates the primary engineering science principles involved in gasifier-engine system design. It arises from and supplements a WKU mechanical engineering senior project. The senior project has developed a wood gasification system designed to power a riding lawn mower. The thesis reiews theory-based design and separates it from informal hit and miss approaches—rule …

Detection Of Structural Bolt Detorquing Using Direct Stethoscope Measurement, Joe Guarino, Robert Hamilton

Mechanical and Biomedical Engineering Faculty Publications and Presentations

A method for detecting loosened bolts in a structural joint based upon open-loop acoustic measurement is presented. The acoustic measurement is taken directly on the bolt head. The response of the bolt to a proximal hammer impact is evaluated and characterized using wavelet decomposition of the signal measured from the bolt head. Data were also taken from an accelerometer mounted longitudinally and transversely on the bolt head. Results from the stethoscope and the accelerometer are presented from a set of structural bolts in several conditions of preload and looseness. A stethoscope applied to the loose bolt and a proximal bolt …

Development Of Peritoneal Microbubble Oxygenation As An Extrapulmonary Treatment For Hypoxia, Nathan Legband

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

Patients affected by a respiratory disease or injury experience a substantially impaired respiratory system and as a consequence are unable to obtain a sufficient amount of oxygen. Hypoxia can quickly result in developing permanent tissue damage or death. Currently, the medical methods of treating hypoxia are mechanical ventilation or extracorporeal membrane oxygenation. However, these treatments are ineffective in certain cases and possess significant additional risks including barotrauma, infection, hemorrhage, and thrombosis.

The extrapulmonary method of peritoneal oxygenation has been investigated by other research groups as a potential alternative to providing supplemental oxygen in hypoxic animals. In peritoneal oxygenation, the peritoneum, …

Design And Validation Of An In Vivo Long-Term Attachment Capsule Robot, Wanchuan Xie

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

The invention of capsule endoscopy (CE) made the non-invasive monitoring of the entire small bowel possible and became the primary means for diagnosing small bowel pathology. In the last decade, capsule robots have been transformed from diagnostic devices into a widely studied biomedical platform with the potential for active locomotion, drug delivery and therapeutic capabilities. To perform accurate on-site drug release and therapy, it is necessary for a capsule robot to be able to attach to the intestinal tissue and maintain its position long-term. Design challenges derive from the task of long-term mucosal adhesion which requires firm, quick-response attachment without …

Method And Shear-Driven Micro-Fluidic Pump, Nihad E. Daidzic

Aviation Department Publications

United States Patent Application, Publication Number US 2017/0096990 A1, Publication Date April 6, 2017.

An example includes an apparatus to pump a fluid. The apparatus includes a housing extending along a length defining an elongate interior, an actuator in the housing, conforming to the elongate interior, the actuator including a plurality of lumens, each having a length extending substantially parallel to the elongate interior, each from around 10 to 200 micrometers across and an actuator configured to oscillate the actuator in the actuator housing along the length of the elongate interior with a rate differential between movement in a first …

Biophysical Tools To Study Cellular Mechanotransduction, Ismeel Muhamed, Farhan Chowdhury, Venkat Maruthamuthu

Mechanical & Aerospace Engineering Faculty Publications

The cell membrane is the interface that volumetrically isolates cellular components from the cell's environment. Proteins embedded within and on the membrane have varied biological functions: reception of external biochemical signals, as membrane channels, amplification and regulation of chemical signals through secondary messenger molecules, controlled exocytosis, endocytosis, phagocytosis, organized recruitment and sequestration of cytosolic complex proteins, cell division processes, organization of the cytoskeleton and more. The membrane's bioelectrical role is enabled by the physiologically controlled release and accumulation of electrochemical potential modulating molecules across the membrane through specialized ion channels (e.g., Na^⁺, Ca²⁺, K^⁺ channels). …