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- All Subjects: Ultrasound
Description
This purpose of this study was to develop reliable methods for ultrasound measurements of skeletal muscle architecture, and to identify which specific quadriceps measurements most closely relate to peak isometric torque of the leg extensors. These data were obtained as part of a larger research study and consist of 9 total subjects (4 males, 5 females; age (30.6 ± 13.6yr). Ultrasound images for muscle thickness and pennation angle were obtained for each subject during two separate testing days (separated by 5-10 days). Images were acquired at various anatomical sites of the quadriceps and each image was analyzed using Image J software. Quadriceps muscles assessed for muscle thickness and pennation angle included the vastus lateralis (VL), and vastus intermedius (VI), while rectus femoris (RF) was assessed only for muscle thickness. Peak isometric torque measurements were obtained at 60 degrees of knee angle for knee extension using an isokinetic dynamometer. Results show that the methods chosen for ultrasound measurement produced reliable inter-day results for muscle thickness and pennation angle. VL muscle thickness and pennation angle obtained at the lateral site corresponding to 39% of leg length was highly related to peak isometric torque for knee extension. The results of this study identify specific measurement sites that are related to muscle function. In addition, these data further validate that ultrasound measurement is reliable to measure muscle thickness and pennation angle in skeletal muscle.
ContributorsSkotak, Nathaniel James (Author) / Dickinson, Jared (Thesis director) / Vidt, Meghan (Committee member) / Luden, Nick (Committee member) / School of Nutrition and Health Promotion (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
Desorption processes are an important part of all processes which involve utilization of solid adsorbents such as adsorption cooling, sorption thermal energy storage, and drying and dehumidification processes and are inherently energy-intensive. Here, how those energy requirements can be reduced through the application of ultrasound for three widely used adsorbents namely zeolite 13X, activated alumina and silica gel is investigated. To determine and justify the effectiveness of incorporating ultrasound from an energy-savings point of view, an approach of constant overall input power of 20 and 25 W was adopted. To measure the extent of the effectiveness of using ultrasound, the ultrasonic-power-to-total power ratios of 0.2, 0.25, 0.4 and 0.5 were investigated and the results compared with those of no-ultrasound (heat only) at the same total power. Duplicate experiments were performed at three nominal frequencies of 28, 40 and 80 kHz to observe the influence of frequency on regeneration dynamics. Regarding moisture removal, application of ultrasound results in higher desorption rate compared to a non-ultrasound process. A nonlinear inverse proportionality was observed between the effectiveness of ultrasound and the frequency at which it is applied. Based on the variation of desorption dynamics with ultrasonic power and frequency, three mechanisms of reduced adsorbate adsorption potential, increased adsorbate surface energy and enhanced mass diffusion are proposed. Two analytical models that describe the desorption process were developed based on the experimental data from which novel efficiency metrics were proposed, which can be employed to justify incorporating ultrasound in regeneration and drying processes.
ContributorsDaghooghi Mobarakeh, Hooman (Author) / Phelan, Patrick (Thesis advisor) / Wang, Liping (Committee member) / Wang, Robert (Committee member) / Calhoun, Ronald (Committee member) / Deng, Shuguang (Committee member) / Arizona State University (Publisher)
Created2021