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Full-Text Articles in Mechanical Engineering

How Dynamic Adsorption Controls Surfactant‑Enhanced Boiling, Mario R. Mata, Brandon Ortiz, Dhruv Luhar, Vesper Evereux, H. Jeremy Cho Oct 2022

How Dynamic Adsorption Controls Surfactant‑Enhanced Boiling, Mario R. Mata, Brandon Ortiz, Dhruv Luhar, Vesper Evereux, H. Jeremy Cho

Mechanical Engineering Faculty Research

No abstract provided.


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 …


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 …


Material Model Characterization Of A Ti/Sic Metal Matrix Nanocomposite Coating Subjected To Hypervelocity Impact, Pouya Shojaei, Riccardo Scazzosi, Mohamed Trabia, Brendan Otoole, Marco Giglio, Xing Zhang, Yiliang Liao, Andrea Manes Dec 2020

Material Model Characterization Of A Ti/Sic Metal Matrix Nanocomposite Coating Subjected To Hypervelocity Impact, Pouya Shojaei, Riccardo Scazzosi, Mohamed Trabia, Brendan Otoole, Marco Giglio, Xing Zhang, Yiliang Liao, Andrea Manes

Mechanical Engineering Faculty Research

Titanium alloys have been extensively used in the aerospace industry because of their outstanding properties, such as high strength-to-weight ratios, high corrosion resistances, and high melting points. However, it is hypothesized that the performance of titanium alloys can be further enhanced to be more resistant to hypervelocity impact by coating them. Earlier experimental investigations showed that coating a Ti-6Al-4V substrate by Ti/SiC Metal Matrix Nanocomposite (MMNC) improved hypervelocity impact resistance of the composite. The coating had 7% SiC by volume. These experiments were simulated using the Smoothed Particle Hydrodynamics (SPH) modeling approach. Johnson-Cook material models were used for the Ti-6Al-4V …


Multidirectional Cylindrical Piezoelectric Force Sensor: Design And Experimental Validation, Ye Rim Lee, Justin Neubauer, Kwang Jin Kim, Youngsu Cha Aug 2020

Multidirectional Cylindrical Piezoelectric Force Sensor: Design And Experimental Validation, Ye Rim Lee, Justin Neubauer, Kwang Jin Kim, Youngsu Cha

Mechanical Engineering Faculty Research

A common design concept of the piezoelectric force sensor, which is to assemble a bump structure from a flat or fine columnar piezoelectric structure or to use a specific type of electrode, is quite limited. In this paper, we propose a new design of cylindrical piezoelectric sensors that can detect multidirectional forces. The proposed sensor consists of four row and four column sensors. The design of the sensor was investigated by the finite element method. The response of the sensor to various force directions was observed, and it was demonstrated that the direction of the force applied to the sensor …


Fabrication Of Hard–Soft Microfluidic Devices Using Hybrid 3d Printing, Carlos Ruiz, Karteek Kadimisetty, Kun Yin, Michael G. Mauk, Hui Zhao, Changchun Liu Jun 2020

Fabrication Of Hard–Soft Microfluidic Devices Using Hybrid 3d Printing, Carlos Ruiz, Karteek Kadimisetty, Kun Yin, Michael G. Mauk, Hui Zhao, Changchun Liu

Mechanical Engineering Faculty Research

Widely accessible, inexpensive, easy-to-use consumer 3D printers, such as desktop stereolithography (SLA) and fused-deposition modeling (FDM) systems are increasingly employed in prototyping and customizing miniaturized fluidic systems for diagnostics and research. However, these 3D printers are generally limited to printing parts made of only one material type, which limits the functionality of the microfluidic devices without additional assembly and bonding steps. Moreover, mating of different materials requires good sealing in such microfluidic devices. Here, we report methods to print hybrid structures comprising a hard, rigid component (clear polymethacrylate polymer) printed by a low-cost SLA printer, and where the first printed …


Design And Modeling Of A New Biomimetic Soft Robotic Jellyfish Using Ipmc-Based Electroactive Polymers, Zakai J. Olsen, Kwang J. Kim Nov 2019

Design And Modeling Of A New Biomimetic Soft Robotic Jellyfish Using Ipmc-Based Electroactive Polymers, Zakai J. Olsen, Kwang J. Kim

Mechanical Engineering Faculty Research

Smart materials and soft robotics have been seen to be particularly well-suited for developing biomimetic devices and are active fields of research. In this study, the design and modeling of a new biomimetic soft robot is described. Initial work was made in the modeling of a biomimetic robot based on the locomotion and kinematics of jellyfish. Modifications were made to the governing equations for jellyfish locomotion that accounted for geometric differences between biology and the robotic design. In particular, the capability of the model to account for the mass and geometry of the robot design has been added for better …


Silica-Coated Metallic Nanoparticle-Based Hierarchical Super-Hydrophobic Surfaces Fabricated By Spin-Coating And Inverse Nanotransfer Printing, Shengjie Zhai, Hui Zhao Jun 2019

Silica-Coated Metallic Nanoparticle-Based Hierarchical Super-Hydrophobic Surfaces Fabricated By Spin-Coating And Inverse Nanotransfer Printing, Shengjie Zhai, Hui Zhao

Mechanical Engineering Faculty Research

By combining spin coating and inverse nanotransfer printing, silica-coated gold nanoparticles are patterned onto polydimethylsiloxane (PDMS) superhydrophobic surfaces to form a hierarchical structure. A layer of nanoparticles is spin-coated on a flat silicon substrate serving as the stamp, which is then transferred to the raised regions of PDMS surfaces. Our inverse nanotransfer printing is in contrast to the standard nanotransfer printing, which transfers metal from the raised regions of a stamp to a flat PDMS surface. The fabricated hierarchical surface exhibits a higher contact angle and delays the Cassie-Wenzel transition during evaporation of a sessile droplet, indicating an improvement of …


Non-Einstein Viscosity Phenomenon Of Acrylonitrile–Butadiene–Styrene Composites Containing Lignin–Polycaprolactone Particulates Highly Dispersed By High-Shear Stress, Sing-Hoon Kim, Kisuk Choi, Kyouk Ryeol Choi, Taesung Kim, Jonghwan Suhr, Kwang Jin Kim, Hyoung Jin Choi, Jae-Do Nam Jun 2019

Non-Einstein Viscosity Phenomenon Of Acrylonitrile–Butadiene–Styrene Composites Containing Lignin–Polycaprolactone Particulates Highly Dispersed By High-Shear Stress, Sing-Hoon Kim, Kisuk Choi, Kyouk Ryeol Choi, Taesung Kim, Jonghwan Suhr, Kwang Jin Kim, Hyoung Jin Choi, Jae-Do Nam

Mechanical Engineering Faculty Research

Lignin powder was modified via ring-opening polymerization of caprolactone to form a lignin–polycaprolactone (LPCL) particulate. The LPCL particulates were mixed with an acrylonitrile–butadiene–styrene (ABS) matrix at an extremely high rotational speed of up to 3000 rpm, which was achieved by a closed-loop screw mixer and in-line melt extruder. Using this high-shear extruding mixer, the LPCL particulate size was controlled in the range of 3395 nm (conventional twin-screw extrusion) down to 638 nm (high-shear mixer of 3000 rpm) by altering the mixing speed and time. The resulting LPCL/ABS composites clearly showed non-Einstein viscosity phenomena, exhibiting reduced viscosity (2130 Pa·s) compared to …


Introduction For The Special Issue On Beyond The Hypes Of Geospatial Big Data: Theories, Methods, Analytics, And Applications, Qianxing Wang, Allison Kealy, Shengjie Zhai Jan 2019

Introduction For The Special Issue On Beyond The Hypes Of Geospatial Big Data: Theories, Methods, Analytics, And Applications, Qianxing Wang, Allison Kealy, Shengjie Zhai

Mechanical Engineering Faculty Research

We live in the era of ‘Big Data’. In particular, Geospatial data, whether captured through remote sensors (e.g., satellite imagery) or generated from large-scale simulations (e.g., climate change models) have always been significantly large in size. Over the last decade however, advances in instrumentation and computation has seen the volume, variety, velocity, and veracity of this data increase exponentially. Of the 2.5 quintillion (1018) bytes of data that are generated on a daily basis across the globe, a large portion (arguably as much as 80%) is found to be geo-referenced. Therefore, this special issue is dedicated to the innovative theories, …


Electroactive Artificial Muscles Based On Functionally Antagonistic Core–Shell Polymer Electrolyte Derived From Ps-B-Pss Block Copolymer, Van Hiep Nguyen, Jaehwan Kim, Rassoul Tabassian, Moumita Kotal, Kiwoo Jun, Jung-Hwan Oh, Ji-Myeong Son, Muhammad Taha Manzoor, Kwang Jin Kim, Il-Kwon Oh Dec 2018

Electroactive Artificial Muscles Based On Functionally Antagonistic Core–Shell Polymer Electrolyte Derived From Ps-B-Pss Block Copolymer, Van Hiep Nguyen, Jaehwan Kim, Rassoul Tabassian, Moumita Kotal, Kiwoo Jun, Jung-Hwan Oh, Ji-Myeong Son, Muhammad Taha Manzoor, Kwang Jin Kim, Il-Kwon Oh

Mechanical Engineering Faculty Research

Electroactive ionic soft actuators, a type of artificial muscles containing a polymer electrolyte membrane sandwiched between two electrodes, have been intensively investigated owing to their potential applications to bioinspired soft robotics, wearable electronics, and active biomedical devices. However, the design and synthesis of an efficient polymer electrolyte suitable for ion migration have been major challenges in developing high-performance ionic soft actuators. Herein, a highly bendable ionic soft actuator based on an unprecedented block copolymer is reported, i.e., polystyrene-b-poly(1-ethyl-3-methylimidazolium-4-styrenesulfonate) (PS-b-PSS-EMIm), with a functionally antagonistic core–shell architecture that is specifically designed as an ionic exchangeable polymer electrolyte. The corresponding actuator shows exceptionally …


First Observation Of P-Odd Gamma Asymmetry In Polarized Neutron Capture On Hydrogen, D. Blyth, J. Fry, N. Fomin, R. Alarcon, L. Alonzi, E. Askanazi, S. Baeßler, S. Balascuta, L. Barrón-Palos, Alex Barzilov, J. D. Bowman, N. Birge, J. R. Calarco, T. E. Chupp, V. Cianciolo, C. E. Coppola, C. B. Crawford, K. Craycraft, D. Evans, C. Fieseler, E. Frlež, I. Garishvili, M. T. W. Gericke, R. C. Gillis, K. B. Grammer, G. L. Greene, J. Hall, J. Hamblen, C. Hayes, E. B. Iverson, M. L. Kabir Dec 2018

First Observation Of P-Odd Gamma Asymmetry In Polarized Neutron Capture On Hydrogen, D. Blyth, J. Fry, N. Fomin, R. Alarcon, L. Alonzi, E. Askanazi, S. Baeßler, S. Balascuta, L. Barrón-Palos, Alex Barzilov, J. D. Bowman, N. Birge, J. R. Calarco, T. E. Chupp, V. Cianciolo, C. E. Coppola, C. B. Crawford, K. Craycraft, D. Evans, C. Fieseler, E. Frlež, I. Garishvili, M. T. W. Gericke, R. C. Gillis, K. B. Grammer, G. L. Greene, J. Hall, J. Hamblen, C. Hayes, E. B. Iverson, M. L. Kabir

Mechanical Engineering Faculty Research

We report the first observation of the parity-violating gamma-ray asymmetry A(gamma)(np) in neutron-proton capture using polarized cold neutrons incident on a liquid parahydrogen target at the Spallation Neutron Source at Oak Ridge National Laboratory. A(gamma)(np) isolates the Delta I = 1, S-3(1)-> P-3(1) component of the weak nucleon-nucleon interaction, which is dominated by pion exchange and can be directly related to a single coupling constant in either the DDH meson exchange model or pionless effective field theory… See full text for full abstract.


Simulation Of The Oxygen Reduction Reaction (Orr) Inside The Cathode Catalyst Layer (Ccl) Of Proton Exchange Membrane Fuel Cells Using The Kinetic Monte Carlo Method, Baosheng Bai, Yi-Tung Chen Sep 2018

Simulation Of The Oxygen Reduction Reaction (Orr) Inside The Cathode Catalyst Layer (Ccl) Of Proton Exchange Membrane Fuel Cells Using The Kinetic Monte Carlo Method, Baosheng Bai, Yi-Tung Chen

Mechanical Engineering Faculty Research

In this paper, a numerical model of the kinetic Monte Carlo (KMC) method has been developed to study the oxygen reduction reaction (ORR) that occurs inside the cathode catalyst layer (CCL). Firstly, a 3-D model of the CCL that consists of Pt and carbon spheres is built using the sphere packing method; secondly, an efficient procedure of the proton-oxygen reaction process is developed and simulated. In the proton-oxygen reaction process, all of the continuous movements of protons and oxygen are considered. The maximum reaction distance is determined to be 8 Å. The input pressures of protons and oxygen are represented …


Understanding The Thermal Properties Of Precursor-Ionomers To Optimize Fabrication Processes For Ionic Polymer-Metal Composites (Ipmcs), Sarah Trabia, Kisuk Choi, Zakai Olsen, Taeseon Hwang, Jae-Do Nam, Kwang J. Kim Apr 2018

Understanding The Thermal Properties Of Precursor-Ionomers To Optimize Fabrication Processes For Ionic Polymer-Metal Composites (Ipmcs), Sarah Trabia, Kisuk Choi, Zakai Olsen, Taeseon Hwang, Jae-Do Nam, Kwang J. Kim

Mechanical Engineering Faculty Research

Ionic polymer-metal composites (IPMCs) are one of many smart materials and have ionomer bases with a noble metal plated on the surface. The ionomer is usually Nafion, but recently Aquivion has been shown to be a promising alternative. Ionomers are available in the form of precursor pellets. This is an un-activated form that is able to melt, unlike the activated form. However, there is little study on the thermal characteristics of these precursor ionomers. This lack of knowledge causes issues when trying to fabricate ionomer shapes using methods such as extrusion, hot-pressing, and more recently, injection molding and 3D printing. …


Mechanical Properties And Flame Retardancy Of Surface Modified Magnesium Oxysulfate (5mg(Oh)2·Mgso4·3h2o) Whisker For Polypropylene Composites, Eui-Su Kim, Ye Chan Kim, Jungwoo Park, Youngjun Kim, Sung-Hoon Kim, Kwang Jin Kim, Jonghwan Suhr, Youngkwan Lee, Seong Hoon Lee, Dae-Sik Kim, Soo-Hyun Kim, Ju-Ho Yun, In-Kyung Park, Jae-Do Nam Feb 2018

Mechanical Properties And Flame Retardancy Of Surface Modified Magnesium Oxysulfate (5mg(Oh)2·Mgso4·3h2o) Whisker For Polypropylene Composites, Eui-Su Kim, Ye Chan Kim, Jungwoo Park, Youngjun Kim, Sung-Hoon Kim, Kwang Jin Kim, Jonghwan Suhr, Youngkwan Lee, Seong Hoon Lee, Dae-Sik Kim, Soo-Hyun Kim, Ju-Ho Yun, In-Kyung Park, Jae-Do Nam

Mechanical Engineering Faculty Research

Magnesium oxysulfate (MOS) whisker is considered as a promising inorganic material recently attracting a great attention for being used as a reinforcing filler for polymer composites due to high aspect ratio and extremely-low bulk density. In this study, the MOS was treated with 3-methacryloyloxypropyl-trimethoxy silane (MPS) via sol-gel condensation reactions, which successfully allowed melt mixing with polypropylene (PP) up to 30 wt% of MOS. The tensile strength at yield and modulus of the MOS/PP composites were substantially increased by 50.8% and 362%, respectively, when compared with the pristine PP. As a novel finding, the flame retardancy of MOS was proved …


A Localized Meshless Technique For Generating 3-D Wind Fields, Darrell W. Pepper, Maria Ramos Gonzalez Feb 2018

A Localized Meshless Technique For Generating 3-D Wind Fields, Darrell W. Pepper, Maria Ramos Gonzalez

Mechanical Engineering Faculty Research

A localized meshless method is used to simulate 3-D atmospheric wind fields for wind energy assessment and emergency response. The meshless (or mesh-free) method with radial basis functions (RBFs) alleviates the need to create a mesh required by finite difference, finite volume, and finite element methods. The method produces a fast solution that converges with high accuracy, establishing 3-D wind estimates over complex terrain. The method does not require discretization of the domain or boundary and removes the need for domain integration. The meshless method converges exponentially for smooth boundary shapes and boundary data, and is insensitive to dimensional constraints. …


Parameters Identification For A Composite Piezoelectric Actuator Dynamics, Mohammad Saadeh, Mohamed Trabia Mar 2015

Parameters Identification For A Composite Piezoelectric Actuator Dynamics, Mohammad Saadeh, Mohamed Trabia

Mechanical Engineering Faculty Research

This work presents an approach for identifying the model of a composite piezoelectric (PZT) bimorph actuator dynamics, with the objective of creating a robust model that can be used under various operating conditions. This actuator exhibits nonlinear behavior that can be described using backlash and hysteresis. A linear dynamic model with a damping matrix that incorporates the Bouc–Wen hysteresis model and the backlash operators is developed. This work proposes identifying the actuator’s model parameters using the hybrid master-slave genetic algorithm neural network (HGANN). In this algorithm, the neural network exploits the ability of the genetic algorithm to search globally to …


A Versatile Microparticle-Based Immunoaggregation Assay For Macromolecular Biomarker Detection And Quantification, Haiyan Wu, Yu Han, George G. Chase, Qiong Tang, Chen-Jung Lee, Bin Cao, Jiang Zhe, Gang Cheng Feb 2015

A Versatile Microparticle-Based Immunoaggregation Assay For Macromolecular Biomarker Detection And Quantification, Haiyan Wu, Yu Han, George G. Chase, Qiong Tang, Chen-Jung Lee, Bin Cao, Jiang Zhe, Gang Cheng

Mechanical Engineering Faculty Research

The rapid, sensitive and low-cost detection of macromolecular biomarkers is critical in clinical diagnostics, environmental monitoring, research, etc. Conventional assay methods usually require bulky, expensive and designated instruments and relative long assay time. For hospitals and laboratories that lack immediate access to analytical instruments, fast and low-cost assay methods for the detection of macromolecular biomarkers are urgently needed. In this work, we developed a versatile microparticle (MP)-based immunoaggregation method for the detection and quantification of macromolecular biomarkers. Antibodies (Abs) were firstly conjugated to MP through streptavidin-biotin interaction; the addition of macromolecular biomarkers caused the aggregation of Ab-MPs, which were subsequently …


Novel Quantitative Macro Biomolecule Analysis Based On A Micro Coulter Counter, Y Han, H. Wu, F. Liu, Gang Cheng, Jiang Zhe Oct 2014

Novel Quantitative Macro Biomolecule Analysis Based On A Micro Coulter Counter, Y Han, H. Wu, F. Liu, Gang Cheng, Jiang Zhe

Mechanical Engineering Faculty Research

We demonstrate quantitative biomolecule analysis using a micro coulter counter. Specific binding between antibody functionalized microparticles and target biomolecule cause large aggregates of microparticles. The micro coulter counter was employed to measure aggregation ratio, ratio of the aggregate counts to the total particle counts. Goat anti-rabbit IgG, used as a model biomarker, were tested in this paper. The experiment results showed that the aggregation ratio increases with the increasing biomolecule concentration, and the detectable concentration range from 16 to 160 ng/ml was achieved.


Passive Continuous Particle Focusing In A Microchannel With Symmetric Sharp Corner Structures, Liang-Liang Fan, Liang Zhao, Xu-Kun He, Hand Yu, Qing-Yu Wei, Jiang Zhe Oct 2014

Passive Continuous Particle Focusing In A Microchannel With Symmetric Sharp Corner Structures, Liang-Liang Fan, Liang Zhao, Xu-Kun He, Hand Yu, Qing-Yu Wei, Jiang Zhe

Mechanical Engineering Faculty Research

We report a continuous passive particle focusing method using a novel microchannel with symmetric sharp corners which induce curved streamlines and large centrifugal force on particles. At appropriate flow rate, the centrifugal force generated on particles exceeds the inertial lift force; particles driven by the centrifugal force migrate toward the center of the microchannel, achieving continuous particle focus-ing. With simple structure and operation, this method can be potentially used in particle focusing and ex-traction processes in a variety of lab-on-a chip applications.


A New Microfluidic Device For Complete, Continuous Separation Of Microparticles, Liang-Liang Fan, Xu-Kun He, Yu Han, Li Du, Liang Zhao, Jiang Zhe Oct 2014

A New Microfluidic Device For Complete, Continuous Separation Of Microparticles, Liang-Liang Fan, Xu-Kun He, Yu Han, Li Du, Liang Zhao, Jiang Zhe

Mechanical Engineering Faculty Research

A microchannel with symmetric sharp corners is reported for particle separation, based on the inter-play between the inertial lift force and the centrifugal force induced by sharp corners. At an appropriate flow rate, the centrifugal force is larger than the inertial lift force on large particles, while the inertial lift force is dominant on small particles. Hence large particles are centrifuged to the center, while small par-ticles are focused at side streams, achieving complete particle separation. The device requires no sheath flow, avoiding the dilution of analyte sample and complex operation, and can be potentially used for many lab-on-a-chip applications.


Reinterpretation Of Velocity-Dependent Atomic Friction: Influence Of The Inherent Instrumental Noise In Friction Force Microscopes, Yalin Dong, Hongyu Gao, Ashlie Martini, Philip Egberts Jul 2014

Reinterpretation Of Velocity-Dependent Atomic Friction: Influence Of The Inherent Instrumental Noise In Friction Force Microscopes, Yalin Dong, Hongyu Gao, Ashlie Martini, Philip Egberts

Mechanical Engineering Faculty Research

We have applied both the master equation method and harmonic transition state theory to interpret the velocity-dependent friction behavior observed in atomic friction experiments. To understand the discrepancy between attempt frequencies measured in atomic force microscopy experiments and those estimated by theoretical models, both thermal noise and instrumental noise are introduced into the model. It is found that the experimentally observed low attempt frequency and the transition point at low velocity regimes can be interpreted in terms of the instrumental noise inherent in atomic force microscopy. In contrast to previous models, this model also predicts (1) the existence of a …


Numerical Analysis Of Cold Injury Of Skin In Cryogen Spray Cooling For Laser Dermatologic Surgery, Dong Li, Bin Chen, Wen-Juan Wu, Ya-Ling He, Lin Zhuang Xing, Guo-Xiang Wang Mar 2014

Numerical Analysis Of Cold Injury Of Skin In Cryogen Spray Cooling For Laser Dermatologic Surgery, Dong Li, Bin Chen, Wen-Juan Wu, Ya-Ling He, Lin Zhuang Xing, Guo-Xiang Wang

Mechanical Engineering Faculty Research

In laser dermatologic surgery, cryogen spray cooling (CSC) is used to avoid unwanted thermal damage such as scars from skin burning due to the melanin absorption of the laser beam. As the cryogen is fully atomized from the nozzle, temperature of the droplets can quickly drop below -60 oC because of evaporation. Such low temperature may lead to cold injury of skin. Therefore, spray cooling process should be accurately controlled during clinical practice to achieve sufficient protection and avoid cold injury. This study presents a numerical analysis for cold injury of skin in cryogen spray cooling for dermatologic laser surgery …


The General Public’S Weather Information-Seeking And Decision-Making Behavior During Tornado Outbreaks In The Oklahoma City Metroplex In May 2013, Chen Ling, Michelle Madison, Jessica Adams, Kevin Warren, Michael Mudd, Kim Graves Wolfinbarger, Lans Rothfusz Feb 2014

The General Public’S Weather Information-Seeking And Decision-Making Behavior During Tornado Outbreaks In The Oklahoma City Metroplex In May 2013, Chen Ling, Michelle Madison, Jessica Adams, Kevin Warren, Michael Mudd, Kim Graves Wolfinbarger, Lans Rothfusz

Mechanical Engineering Faculty Research

Severe weather impacts the lives of many people. Today's technology allows weather information to be distributed to the general public in many ways. However, it is not clear how people obtain information regarding severe weather, and how they make decisions based on the information. This study surveyed people in the Oklahoma City metroplex about their weather information–seeking and decision-making behaviors during the May 2013 tornado outbreaks. The preliminary results based on 124 survey responses show that people used and trusted television news most to obtain the severe weather information, followed by siren, weather radio, radio, looking at the sky, and …


Electromyogram Synergy Control Of A Dexterous Artificial Hand To Unscrew And Screw Objects, Benjamin A. Kent, Nareen Karnati, Erik D. Engeberg Jan 2014

Electromyogram Synergy Control Of A Dexterous Artificial Hand To Unscrew And Screw Objects, Benjamin A. Kent, Nareen Karnati, Erik D. Engeberg

Mechanical Engineering Faculty Research

Due to their limited dexterity, it is currently not possible to use a commercially available prosthetic hand to unscrew or screw objects without using elbow and shoulder movements. For these tasks, prosthetic hands function like a wrench, which is unnatural and limits their use in tight working environments. Results from timed rotational tasks with human subjects demonstrate the clinical need for increased dexterity of prosthetic hands, and a clinically viable solution to this problem is presented for an anthropomorphic artificial hand.


Active Infrared Sensing Of Impact Damage In Carbon Fibre Reinforced Polymer, Kwek Tze Tan, Liping Zhao, Shaochun Ye, Tong Kuan Chuah, Pramoda Kumari Pallathadka, Hui Ru Tan Jan 2014

Active Infrared Sensing Of Impact Damage In Carbon Fibre Reinforced Polymer, Kwek Tze Tan, Liping Zhao, Shaochun Ye, Tong Kuan Chuah, Pramoda Kumari Pallathadka, Hui Ru Tan

Mechanical Engineering Faculty Research

With the growing demand of carbon fibre reinforced plastic (CFRP) in aerospace, marine and automobile industries, much attention is devoted to characterizing the material strength and characteristics of failure. This paper demonstrated the feasibility to estimate the internal damage non-destructively as a result of a quantified impact applied on 16-ply fabric CFRP. On thermography images at different heating time, differences were observed between intact area and area with internal damage. The estimation of 1D extent of damage using thermographic analysis was compared with images observed with cross sectional microscopic. The results suggest that qualitative analysis using thermography shows potential to …


Measurement Of Adhesion Energy Of Electrospun Polymer Membranes Using A Shaft-Loaded Blister Test, Shing Chung Josh Wong, Haining Na, Pei Chen Jun 2013

Measurement Of Adhesion Energy Of Electrospun Polymer Membranes Using A Shaft-Loaded Blister Test, Shing Chung Josh Wong, Haining Na, Pei Chen

Mechanical Engineering Faculty Research

This study aims to examine the adhesion work of electrospun polymer nano- and micro-fibers. The adhesion energy at the interface of electrospun membrane and a rigid substrate is characterized by a shaft-loaded blister test (SLBT). By controlling the processing parameters, polyvinylidene fluoride (PVDF) fibrous membranes are prepared with fiber diameters ranging from 201 ± 86 nm to 2,724 ± 587 nm. The adhesion energy between electrospun membrane and rigid substrate increases from 8.1 ± 0.7 mJ/m2 to 258.8 ± 43.5 mJ/m2 by use of smaller fiber diameters. Adhesion energies between electrospun PVDF membranes and SiC substrates made of different grain …