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Full-Text Articles in Engineering

Use Of Pressure-Measuring Insoles To Characterize Gait Parameters In Simulated Reduced-Gravity Conditions, Christian Ison, Connor Neilsen, Jessica Deberardinis, Mohamed B. Trabia, Janet S. Dufek Sep 2021

Use Of Pressure-Measuring Insoles To Characterize Gait Parameters In Simulated Reduced-Gravity Conditions, Christian Ison, Connor Neilsen, Jessica Deberardinis, Mohamed B. Trabia, Janet S. Dufek

Mechanical Engineering Faculty Research

Prior researchers have observed the effect of simulated reduced-gravity exercise. However, the extent to which lower-body positive-pressure treadmill (LBPPT) walking alters kinematic gait characteristics is not well understood. The purpose of the study was to investigate the effect of LBPPT walking on selected gait parameters in simulated reduced-gravity conditions. Twenty-nine college-aged volunteers participated in this cross-sectional study. Participants wore pressure-measuring insoles (Medilogic GmBH, Schönefeld, Germany) and completed three 3.5-min walking trials on the LBPPT (AlterG, Inc., Fremont, CA, USA) at 100% (normal gravity) as well as reduced-gravity conditions of 40% and 20% body weight (BW). The resulting insole data were …


Silk Fibroin Supraparticles Created By The Evaporation Of Colloidal Ouzo Droplets, Ashley Lamb, Fengjie He, Shengjie Zhai, Hui Zhao Aug 2021

Silk Fibroin Supraparticles Created By The Evaporation Of Colloidal Ouzo Droplets, Ashley Lamb, Fengjie He, Shengjie Zhai, Hui Zhao

Mechanical Engineering Faculty Research

Due to its high biocompatibility and biodegradability, supraparticles made from silk fibroin—produced from Bombyx mori (B. mori) cocoons—can find various applications in biomedical fields. The evaporation of Ouzo droplets by not requiring energy nor a surfactant is an environmentally friendly, easy, and cost-effective strategy to fabricate three-dimensional supraparticles, tackling the so-called “coffee ring effect” associated with droplet evaporation. Silk fibroins are dissolved into quaternary droplets, comprised of ultrapure water, ethanol, trans-anethole oil, and formic acid. The Ouzo droplet is able to form an oil ring that facilitates the droplet contraction to create a three-dimensional supraparticle. Using the Ouzo effect to …


Under Pressure: Hydrogel Swelling In A Granular Medium, Jean François Louf, Nancy B. Lu, Margaret G. O'Connell, H. Jeremy Cho, Sujit S. Datta Feb 2021

Under Pressure: Hydrogel Swelling In A Granular Medium, Jean François Louf, Nancy B. Lu, Margaret G. O'Connell, H. Jeremy Cho, Sujit S. Datta

Mechanical Engineering Faculty Research

Copyright © 2021 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC). Hydrogels hold promise in agriculture as reservoirs of water in dry soil, potentially alleviating the burden of irrigation. However, confinement in soil can markedly reduce the ability of hydrogels to absorb water and swell, limiting their widespread adoption. Unfortunately, the underlying reason remains unknown. By directly visualizing the swelling of hydrogels confined in three-dimensional granular media, we demonstrate that the extent of hydrogel swelling is …


Morphology Control Of One-Dimensional Gallium Nitride Nanostructures By Modulating The Crystallinity Of Sacrificial Gallium Oxide Templates, Yun Taek Ko, Mijeong Park, Jingyeong Park, Jaeyun Moon, Yong Ho Choa, Young In Lee Jan 2021

Morphology Control Of One-Dimensional Gallium Nitride Nanostructures By Modulating The Crystallinity Of Sacrificial Gallium Oxide Templates, Yun Taek Ko, Mijeong Park, Jingyeong Park, Jaeyun Moon, Yong Ho Choa, Young In Lee

Mechanical Engineering Faculty Research

In this study, we demonstrated a method of controllably synthesizing one-dimensional nanostructures having a dense or a hollow structure using fibrous sacrificial templates with tunable crystallinity. The fibrous ga2o3 templates were prepared by calcining the polymer/gallium precursor nanofiber synthesized by an electrospinning process, and their crystallinity was varied by controlling the calcination temperature from 500oC to 900oC. gaN nanostructures were transformed by nitriding the ga2o3 nanofibers using NH3 gas. All of the transformed gaN nanostructures maintained a one-dimensional structure well and exhibited a diameter of about 50 nm, but their morphology was clearly distinguished according to the crystallinity of the …


Direct Energy Deposition Of Mo Powder Prepared By Electrode Induction Melting Gas Atomization, Goo Won Roh, Eun Soo Park, Jaeyun Moon, Hojun Lee, Jongmin Byun Jan 2021

Direct Energy Deposition Of Mo Powder Prepared By Electrode Induction Melting Gas Atomization, Goo Won Roh, Eun Soo Park, Jaeyun Moon, Hojun Lee, Jongmin Byun

Mechanical Engineering Faculty Research

Molybdenum (Mo) is used to form a barrier layer for metal wiring in displays or semiconductor devices. Recently, researches have been continuously attempted to fabricate Mo sputtering targets through additive manufacturing. in this study, spherical Mo powders with an average particle size of about 37 um were manufactured by electrode induction melting gas atomization. Subsequently, Mo layer with a thickness of 0.25 mm was formed by direct energy deposition in which the scan speed was set as a variable. According to the change of the scan speed, pores or cracks were found in the Mo deposition layer. Mo layer deposited …


Effect Of Heat Treatment On Microstructure And Hardness Of A Worn Rail Repaired Using Laser Powder Deposition, Ershad Mortazavian, Zhiyong Wang, Hualiang Teng Jan 2021

Effect Of Heat Treatment On Microstructure And Hardness Of A Worn Rail Repaired Using Laser Powder Deposition, Ershad Mortazavian, Zhiyong Wang, Hualiang Teng

Mechanical Engineering Faculty Research

The frequent replacement of worn rails on tracks brings an immense economic burden on the railroad industry, and also causes significant interruptions to railroad operation. Restoration of worn rails via laser powder deposition (LPD) can considerably reduce the associated maintenance costs. This study was focused on the use of LPD to repair the worn profile of a standard U.S. rail. The microstructure of the 304L stainless steel deposits with a minimum hardness of 85 HRB was composed of austenite, δ-ferrite, and sigma. Micropores were dispersed throughout the deposit, and microcracks were found at the rail-deposition interface. The pearlitic rail substrate …