Mechanical Engineering Commons^™

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

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

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

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

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

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

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

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

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

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 …

Polymer Fiber Arrays For Adhesion, Shing Chung Josh Wong, Johnny F. Najem, Guang Ji, Shuwen Chen

Mechanical Engineering Faculty Research

The ability of geckos to adhere to vertical solid surfaces comes from their remarkable feet with millions of projections terminating in nanometer spatulae. In this paper, we present a simple yet robust method for fabricating directionally sensitive dry adhesives. By using electrospun nylon 6 nanofiber arrays, we create gecko-inspired dry adhesives, that are electrically insulating, and that show shear adhesion strength of 27 N/cm2 on a glass slide. This measured value is 270% that reported of gecko feet and 97-fold above normal adhesion strength of the same arrays. The data indicate a strong shear binding-on and easy normal lifting-off. Size …

A Mechanism-Based Approach For Predicting Ductile Fracture Of Metallic Alloys, Xiaosheng Gao

Mechanical Engineering Faculty Research

Ductile fracture in metallic alloys often follows a multi-step failure process involving void nucleation, growth and coalescence. Because of the difference in orders of magnitude between the size of the finite element needed to resolve the microscopic details and the size of the engineering structures, homogenized material models, which exhibits strain softening, are often used to simulate the crack propagation process. Various forms of porous plasticity models have been developed for this purpose. Calibration of these models requires the predicted macroscopic stress-strain response and void growth behavior of the representative material volume to match the results obtained from detailed finite …

A Preliminary Discourse On Adhesion Of Nanofibers Derived From Electrospun Polymers, Pei Chen

Mechanical Engineering Faculty Research

To bio-mimic gecko’s foot hair, which possess high adhesion strength and can be re- usable for lifetime, fibrous membranes are fabricated by electrospinning to provide sufficient adhesion energy. Shaft-loaded blister test (SLBT) is firstly used to measure the work of adhesion between electrospun membrane and rigid substrate. Poly(vinylidene fluoride) (PVDF) were electrospun with an average fiber diameter of 333±59 nm. Commercial cardboard with inorganic coating was used to provide a model substrate for adhesion tests. In SLBT, the elastic response PVDF was analyzed and its adhesion energy measured. FEA model with cohesive layer is developed to evaluate the experiment results. …

Adaptive Human Control Gains During Precision Grip, Erik D. Engeberg

Mechanical Engineering Faculty Research

Eight human test subjects attempted to track a desired position trajectory with an instrumented manipulandum (MN). The test subjects used the MN with three different levels of stiffness. A transfer function was developed to represent the human application of a precision grip from the data when the test subjects initially displaced the MN so as to learn the position mapping from the MN onto the display. Another transfer function was formed from the data of the remainder of the experiments, after significant displacement of the MN occurred. Both of these transfer functions accurately modelled the system dynamics for a portion …

Mechanical Behavior Of A Magnesium Alloy Nanocomposite Under Conditions Of Static Tension And Dynamic Fatigue, T. S. Srivatsan, C. Godbole, T. Quick, M. Paramsothy, M. Gupta

Mechanical Engineering Faculty Research

In this paper, the intrinsic influence of nano-alumina particulate (Al₂O_3p) reinforcements on microstructure, microhardness, tensile properties, tensile fracture, cyclic stress-controlled fatigue, and final fracture behavior of a magnesium alloy is presented and discussed. The unreinforced magnesium alloy (AZ31) and the reinforced composite counterpart (AZ31/1.5 vol.% Al₂O₃) were manufactured by solidification processing followed by hot extrusion. The elastic modulus, yield strength, and tensile strength of the nanoparticle-reinforced magnesium alloy were noticeably higher than the unreinforced counterpart. The ductility, quantified by elongation-to-failure, of the composite was observably lower than the unreinforced monolithic counterpart (AZ31). …

Electrospun Polymeric Membranes For Adhesion, Johnny F. Najem, Shing Chung Josh Wong, Guang Ji

Mechanical Engineering Faculty Research

With growing interest in detachable adhesives, new materials are explored such as the types that employ elastomers, thermoplastics, and pressuresensitive polymers [1]. Generally, these adhesives produce substantial shear adhesion strengths but are considerably difficult to detach from surfaces. Commercial high strength adhesives make use of chemical interactions such as glues and permanently attach two surfaces. Subsequently, fabrication of dry adhesives with anisotropic force distributions has the potential in several applications such as tapes, fasteners, treads of wall-climbing robots, spiderman's suits, microelectronics, medical and space applications. High aspect ratio (AR) structures exhibit significant shear adhesion strength compared to ones with low …

Magnetohydrodynamic Simulations Of Hypersonic Flow Over A Cylinder Using Axial- And Transverse-Oriented Magnetic Dipoles, Andrew N. Guarendi, Abhilash J. Chandy

Mechanical Engineering Faculty Research

Numerical simulations of magnetohydrodynamic (MHD) hypersonic flow over a cylinder are presented for axial- and transverse-oriented dipoles with different strengths. ANSYS CFX is used to carry out calculations for steady, laminar flows at a Mach number of 6.1, with a model for electrical conductivity as a function of temperature and pressure. The low magnetic Reynolds number (≪1) calculated based on the velocity and length scales in this problem justifies the quasistatic approximation, which assumes negligible effect of velocity on magnetic fields. Therefore, the governing equations employed in the simulations are the compressible Navier-Stokes and the energy equations with MHD-related source …

Nonoscillatory Central Schemes For Hyperbolic Systems Of Conservation Laws In Three-Space Dimensions, Andrew N. Guarendi, Abhilash J. Chandy

Mechanical Engineering Faculty Research

We extend a family of high-resolution, semidiscrete central schemes for hyperbolic systems of conservation laws to three-space dimensions. Details of the schemes, their implementation, and properties are presented together with results from several prototypical applications of hyperbolic conservation laws including a nonlinear scalar equation, the Euler equations of gas dynamics, and the ideal magnetohydrodynamic equations. Parallel scaling analysis and grid-independent results including contours and isosurfaces of density and velocity and magnetic field vectors are shown in this study, confirming the ability of these types of solvers to approximate the solutions of hyperbolic equations efficiently and accurately.

Coupled Continuum And Molecular Model Of Flow Through Fibrous Filter, Shunliu Zhao, Alex Povitsky

Mechanical Engineering Faculty Research

A coupled approach combining the continuum boundary singularity method (BSM) and the molecular direct simulation Monte Carlo (DSMC) is developed and validated using Taylor-Couette flow and the flow about a single fiber confined between two parallel walls. In the proposed approach, the DSMC is applied to an annular region enclosing the fiber and the BSM is employed in the entire flow domain. The parameters used in the DSMC and the coupling procedure, such as the number of simulated particles, the cell size, and the size of the coupling zone are determined by inspecting the accuracy of pressure drop obtained for …

Physically Representative Atomistic Modeling Of Atomic-Scale Friction, Yalin Dong

Mechanical Engineering Faculty Research

Nanotribology is a research field to study friction, adhesion, wear and lubrication occurred between two sliding interfaces at nano scale. This study is motivated by the demanding need of miniaturization mechanical components in Micro Electro Mechanical Systems (MEMS), improvement of durability in magnetic storage system, and other industrial applications. Overcoming tribological failure and finding ways to control friction at small scale have become keys to commercialize MEMS with sliding components as well as to stimulate the technological innovation associated with the development of MEMS. In addition to the industrial applications, such research is also scientifically fascinating because it opens a …

Comparison Of 4d Phase-Contrast Mri Flow Measurements To Computational Fluid Dynamics Simulations Of Cerebrospinal Fluid Motion In The Cervical Spine, Theresia Yiallourou, Jan Robert Kroger, Nikolaos Stergiopulos, David Maintz, Bryn A. Martin, Alexander C. Bunck

Mechanical Engineering Faculty Research

Cerebrospinal fluid (CSF) dynamics in the cervical spinal subarachnoid space (SSS) have been thought to be important to help diagnose and assess craniospinal disorders such as Chiari I malformation (CM). In this study we obtained time-resolved three directional velocity encoded phase-contrast MRI (4D PC MRI) in three healthy volunteers and four CM patients and compared the 4D PC MRI measurements to subject-specific 3D computational fluid dynamics (CFD) simulations. The CFD simulations considered the geometry to be rigid-walled and did not include small anatomical structures such as nerve roots, denticulate ligaments and arachnoid trabeculae. Results were compared at nine axial planes …

Inertia Gap Between Md Simulations And Afm Experiments In Study Of Atomic Friction, Yalin Dong, Qunyang Li, Robert W. Carpick, Ashlie Martini

Mechanical Engineering Faculty Research

Both atomic force microscopy (AFM) experiments and molecular dynamics (MD) simulation are carried out to investigate atomic stick-slip friction by sliding a Pt tip on an Au substrate. Efforts are taken to match the conditions for AFM experiment and MD simulation as closely as possible. The results show that AFM and MD provide consistent energetic parameters, which suggests that MD simulations can be reliably used to interpret energetic aspects of the interfaces. However, orders of magnitude differences in attempt frequencies are found, which indicates another challenge between the MD simulations and AFM experiments, i.e., the inertia gap.

A Nano-Cheese-Cutter To Directly Measure Interfacial Adhesion Of Freestanding Nano-Fibers, Xin Wang, Johnny F. Najem, Shing Chung Josh Wong, Kai-Tak Wan

Mechanical Engineering Faculty Research

A nano-cheese-cutter is fabricated to directly measure the adhesion between two freestanding nano-fibers. A single electrospun fiber is attached to the free end of an atomic force microscope cantilever, while a similar fiber is similarly prepared on a mica substrate in an orthogonal direction. External load is applied to deform the two fibers into complementary V-shapes, and the force measurement allows the elastic modulus to be determined. At a critical tensile load, “pull-off” occurs when the adhering fibers spontaneously detach from each other, yielding the interfacial adhesion energy. Loading-unloading cycles are performed to investigate repeated adhesion-detachment and surface degradation.

Sheathless Size-Based Acoustic Particle Separation, Rasim Guldiken, Myeong Chan Jo, Nathan D. Gallant, Utkan Demirci, Jiang Zhe

Mechanical Engineering Faculty Research

Particle separation is of great interest in many biological and biomedical applications. Flow-based methods have been used to sort particles and cells. However, the main challenge with flow based particle separation systems is the need for a sheath flow for successful operation. Existence of the sheath liquid dilutes the analyte, necessitates precise flow control between sample and sheath flow, requires a complicated design to create sheath flow and separation efficiency depends on the sheath liquid composition. In this paper, we present a microfluidic platform for sheathless particle separation using standing surface acoustic waves. In this platform, particles are first lined …

Process Completing Sequences For Resource Allocation Systems With Synchronization, Song Foh Chew, Shengyong Wang

Mechanical Engineering Faculty Research

This paper considers the problem of establishing live resource allocation in workflows with synchronization stages. Establishing live resource allocation in this class of systems is challenging since deciding whether a given level of resource capacities is sufficient to complete a single process is NP-complete. In this paper, we develop two necessary conditions and one sufficient condition that provide quickly computable tests for the existence of process completing sequences. The necessary conditions are based on the sequence of completions of � subprocesses that merge together at a synchronization. Although the worst case complexity is O(2�), we expect the number of subprocesses …

Negative Effective Mass Density Of Acoustic Metamaterial Using Dual-Resonator Spring-Mass Model, Kwek Tze Tan, H. H. Huang, C. T. Sun

Mechanical Engineering Faculty Research

In this paper, we propose an acoustic metamaterial with a microstructure consisting of two internal resonators. The performance of this dual-resonator metamaterial is compared to the original singleresonator metamaterial. Analytical findings show that the dual-resonator metamaterial exhibits its negative effective mass density over a larger frequency spectrum, particularly at two distinctively asymptotic regions. The wave propagation phenomenon in the metamaterial is investigated using finite element simulation. Computational results reveal that the dual-resonator metamaterial is capable of attenuating wave propagation in a larger operating frequency. Practical applications like vibration control and blast mitigation are demonstrated and discussed.

Validation Of Delamination Reduction Trend For Stitched Composites Using Quasi-Static Indentation Test, Kwek Tze Tan, N. Watanabe, A. Yoshimura, Y. Iwahori

Mechanical Engineering Faculty Research

A novel empirical-based Delamination Reduction Trend (DRT) for stitched composites has been recently proposed. The DRT is capable of predicting the effective reduction in impact induced delamination area due to the influence of stitching. DRT simply relates two parameters: normalized delamination area and stitch fibre volume fraction, to characterize the effectiveness of stitching in impact damage suppression. This paper seeks to validate the DRT by using quasi-static indentation (QSI) test, which is considered analogous to low velocity impact test, due to similar structural response. Results from QSI test show good agreement with DRT. Furthermore, limitations in DRT have been established.

Design Charts For Circular Fins Of Arbitrary Profile Subject To Radiation And Convection With Wall Resistances, G. Zhang, Benjamin T.F. Chung

Mechanical Engineering Faculty Research

In this work, the optimization for a radiative-convective annular fin of arbitrary profile with base wall thermal resistances is considered. A fourth order Runge-Kutta method is used to solve the associated non-linear governing equa-tions. Further differentiations yield the optimum heat transfer and the optimum fin dimensions. To facilitate the thermal design, design charts for optimum dimensions are proposed. Furthermore, the fin effectiveness for the optimal annular ra-diative-convective fins is presented to check the practicality of the design.

http://dx.doi.org/10.2174/1874396X01206010015

Progressive Damage In Stitched Composites Under Impact Loading, Kwek Tze Tan, N. Watanabe, A. Yoshimura, Y. Iwahori, T. Ishikawa

Mechanical Engineering Faculty Research

Damage in carbon fibre reinforced plastics (CFRP) due to impact loading is an extremely complex phenomenon that comprises of multiple failure mechanisms like intra-laminar matrix cracks, interlaminar delamination, fibre pull-out and fibre fracture. In stitched composites, impact damage behavior is further complicated by the presence of through-thickness stitching [1, 2], which not only favorably increases mode I/II interlaminar strength [3, 4], but also inevitably creates geometrical defects like weak resin-rich pockets around stitch threads and misalignment of in-plane fibres. Computational modeling has been used to simulate progressive damage effectively [5]. However, the complexity of impact damage progression in stitched composites …

Enabling And Understanding Failure Of Engineering Structures Using The Technique Of Cohesive Elements, H. Jiang, Xiaosheng Gao, T. S. Srivatsan

Mechanical Engineering Faculty Research

In this paper, we describe a cohesive zone model for the prediction of failure of engineering solids and/or structures. A damage evolution law is incorporated into a three-dimensional, exponential cohesive law to account for material degradation under the influence of cyclic loading. This cohesive zone model is implemented in the finite element software ABAQUS through a user defined subroutine. The irreversibility of the cohesive zone model is first verified and subsequently applied for studying cyclic crack growth in specimens experiencing different modes of fracture and/or failure. The crack growth behavior to include both crack initiation and crack propagation becomes a …