Engineering Commons^™

Endothelial Function Is Associated With White Matter Microstructure And Executive Function In Older Adults, Nathan F. Johnson, Brian T. Gold, Christopher A. Brown, Emily F. Anggelis, Alison L. Bailey, Jody L. Clasey, David K. Powell

Physical Therapy Faculty Publications

Age-related declines in endothelial function can lead to cognitive decline. However, little is known about the relationships between endothelial function and specific neurocognitive functions. This study explored the relationship between measures of endothelial function (reactive hyperemia index; RHI), white matter (WM) health (fractional anisotropy, FA, and WM hyperintensity volume, WMH), and executive function (Trail Making Test (TMT); Trail B - Trail A). Participants were 36 older adults between the ages of 59 and 69 (mean age = 63.89 years, SD = 2.94). WMH volume showed no relationship with RHI or executive function. However, there was a positive relationship between RHI …

Viscoelastic Analysis And Fatigue Characterization Of Bituminous Materials In Two Length Scales Under The Influence Of Aging, Santosh Reddy Kommidi

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Fatigue cracking in asphalt concrete (AC) is of immense importance to pavement design and analysis because it is one of the most important forms of distress that can lead to structural failure in pavement. Once started, these types of cracks can be combined with other environmental factors leading to detrimental effects such as faster rates of pavement deterioration and shortened pavement life and functionality.

Currently AASHTO TP101, also known as linear amplitude sweep (LAS) specification, is being widely used to evaluate the ability of an asphalt binder to resist fatigue. The LAS method, although mechanistic in its approach, has certain …

The Arm Movement Detection (Amd) Test: A Fast Robotic Test Of Proprioceptive Acuity In The Arm, Leigh A. Mrotek, Maria Bengtson, Tina M. Stoeckmann, Lior Botzer, Claude Ghez, John Mcguire, Robert A. Scheidt

Biomedical Engineering Faculty Research and Publications

Background

We examined the validity and reliability of a short robotic test of upper limb proprioception, the Arm Movement Detection (AMD) test, which yields a ratio-scaled, objective outcome measure to be used for evaluating the impact of sensory deficits on impairments of motor control, motor adaptation and functional recovery in stroke survivors.

Methods

Subjects grasped the handle of a horizontal planar robot, with their arm and the robot hidden from view. The robot applied graded force perturbations, which produced small displacements of the handle. The AMD test required subjects to respond verbally to queries regarding whether or not they detected …

Effective Boronizing Process For Age Hardened Inconel 718, Aria Khalili

Electronic Thesis and Dissertation Repository

Boronizing or boriding is a technique to mitigate wear damage in industrial valves made of age-hardenable Inconel^® 718 which is a nickel-based superalloy. Boriding involves immersing the part in a patented boron-based compound and heating over 800 ^oC.

Boriding combined with aging has a detrimental thermal effect and was the subject of this investigation. The effects on hardness, wear and grain size, of boriding and aging separately, subsequently, and simultaneously, were investigated to observe the microstructure and mechanical properties.

The results show that boriding has negligible effect on the grain size and the hardness of the substrate. Besides, …

White Matter Hyperintensity Associations With Cerebral Blood Flow In Elderly Subjects Stratified By Cerebrovascular Risk, Ahmed A. Bahrani, David K. Powell, Guoqiang Yu, Eleanor S. Johnson, Gregory A. Jicha, Charles D. Smith

Biomedical Engineering Faculty Publications

Objective: This study aims to add clarity to the relationship between deep and periventricular brain white matter hyperintensities (WMHs), cerebral blood flow (CBF), and cerebrovascular risk in older persons. Methods: Deep white matter hyperintensity (dWMH) and periventricular white matter hyperintensity (pWMH) and regional gray matter (GM) and white matter (WM) blood flow from arterial spin labeling were quantified from magnetic resonance imaging scans of 26 cognitively normal elderly subjects stratified by cerebrovascular disease (CVD) risk. Fluidattenuated inversion recovery images were acquired using a high-resolution 3-dimensional (3-D) sequence that reduced partial volume effects seen with slicebased techniques. Results: dWMHs but not …

Evaluation Of Durability And Homogeneity Of Rejuvenated Asphalt Binders, Mojtaba Mohammadafzali

FIU Electronic Theses and Dissertations

Despite the widespread recycling of Reclaimed Asphalt Pavement (RAP), a large portion of it is still wasted. One of the main reasons is the concern with the performance of high RAP mixtures. Asphalt binder aging and subsequent rejuvenation is one source of uncertainty. Rejuvenators are frequently added to high RAP mixes to enhance the properties of the binder. This enhancement is often perceived as simply lowering the viscosity. Two important parameters that are not adequately addressed by existing methods are durability and homogeneity of the recycled binder. This research investigated these two concerns and provided quantitative indicators to measure them. …