Digital Commons Network^™

Laminar Flow In Mini-Fluidics Channels Assembly And Its Application In Zebra Fish Embryo Research, Radek Glaser

Radek Glaser

A Mini-Fluidics system was designed to facilitate the muscle growth of the Zebra Fish embryos. This experimental device is made of peristaltic pump, inflow/outflow manifolds, fluid storage tank, series of valves and flexible pipes and the main plate with six mini channels. These closed channels provide pathways for an extremely laminar flow. The Zebra Fish embryos are placed in the channels and exposed to the forces present in the fluid.

Athermal Resistance To Interface Motion In The Phase-Field Theory Of Microstructure Evolution, Valery I. Levitas, Dong Wook Lee

Valery I. Levitas

A method of introducing an athermal resistance to interface propagation for the Ginzburg-Landau (GL) approach to the first-order phase transformations (PTs) is developed. It consists of introducing oscillating fields of stresses (due to various defects or a Peierls barrier) or a jump in chemical energy. It removes some essential drawbacks in GL modeling: it arrests experimentally observed microstructures that otherwise converge to a single phase, and it reproduces rate-independent stress hysteresis. A similar approach can be applied for twinning, dislocations, and other PTs (e.g., electric and magnetic).

A Bubble-Powered Micro-Rotor: Conception, Manufacturing, Assembly And Characterization, Jonathan Kao, Xiaolin Wang, John Warren, Jie Xu, Daniel Attinger

Daniel Attinger

A steady fluid flow, called microstreaming, can be generated in the vicinity of a micro-bubble excited by ultrasound. In this paper, we use this phenomenon to assemble and power a microfabricated rotor at rotation speeds as high as 625 rpm. The extractible power is estimated to be of the order of a few femtowatts. A first series of experiments with uncontrolled rotor shapes is presented, demonstrating the possibility of this novel actuation scheme. A second series of experiments with 65 µm rotors micromanufactured in SU-8 resin is then presented. Variables controlling the rotation speed and rotor stability are investigated, such …

High-Speed Three-Dimensional Shape Measurement System Using A Modified Twoplus- One Phase-Shifting Algorithm, Song Zhang, Shing-Tung Yau

Song Zhang

This paper describes a high-resolution, real-time, three-dimensional shape measurement system using the modified two-plus-one phase-shifting algorithm. The data acquisition speed is as high as 60frames∕s with an image resolution of 640×480pixels per frame. Experiments demonstrated that the system was able to acquire the dynamic changing objects such as facial geometric shape changes when the subject is speaking, and the modified two-plus-one phase-shifting algorithm can further alleviate the error due to motion. Applications of this system include manufacturing, online inspection, medical imaging, compute vision, and computer graphics.

Repetitive Impact Response Of A Beam Structure Subjected To Harmonic Base Excitation, Elizabeth K. Ervin, Jonathan A. Wickert

Jonathan A. Wickert

This paper investigates the forced response dynamics of a clamped–clamped beam to which a rigid body is attached, and in the presence of periodic or non-periodic impacts between the body and a comparatively compliant base structure. The assembly is subjected to base excitation at specified frequency and acceleration, and the potentially complex responses that occur are examined analytically. The two sets of natural frequencies and vibration modes of the beam-rigid body structure (in its in-contact state, and in its not-in-contact state), are used to treat the forced response problem through a series of algebraic mappings among those states. A modal …

Acoustic Excitation Of Superharmonic Capillary Waves On A Meniscus In A Planar Microgeometry, Jie Xu, Daniel Attinger

Daniel Attinger

The effects of ultrasound on the dynamics of an air-water meniscus in a planar microgeometry are investigated experimentally. The sonicated meniscus exhibits harmonic traveling waves or standing waves, the latter corresponding to a higher ultrasound level. Standing capillary waves with subharmonic and superharmonic frequencies are also observed, and are explained in the framework of parametric resonance theory, using the Mathieu equation.

Evaluation Of Surface Residual Stresses In Friction Stir Welds Due To Laser And Shot Peening, Omar Hatamleh, Iris V. Rivero, Jeds Lyons

Iris V. Rivero

The effects of laser, and shot peening on the residual stresses in friction stir welds (FSW) has been investigated. The surface residual stresses were measured at five different locations across the weld in order to produce an adequate residual stress profile. The residual stresses before and after sectioning the coupon from the welded plate were also measured, and the effect of coupon size on the residual stress relaxation was determined and characterized. Measurements indicate that residual stresses were not uniform along the welded plate, and large variation in stress magnitude could be exhibited at various locations along the FSW plate. …

Platinum Nanoparticle Shape Effects On Benzene Hydrogenation Selectivity, Kaitlin M. Bratlie, Hyunjoo Lee, Kyriakos Komvopoulos, Peidong Yang, Gabor A. Somorjai

Kaitlin M. Bratlie

Benzene hydrogenation was investigated in the presence of a surface monolayer consisting of Pt nanoparticles of different shapes (cubic and cuboctahedral) and tetradecyltrimethylammonium bromide (TTAB). Infrared spectroscopy indicated that TTAB binds to the Pt surface through a weak C-HâââPt bond of the alkyl chain. The catalytic selectivity was found to be strongly affected by the nanoparticle shape. Both cyclohexane and cyclohexene product molecules were formed on cuboctahedral nanoparticles, whereas only cyclohexane was produced on cubic nanoparticles. These results are the same as the product selectivities obtained on Pt(111) and Pt(100) single crystals in earlier studies. The apparent activation energy for …

3d Data Merging Using Holoimage, Song Zhang, Shing-Tung Yau

Song Zhang

Three-dimensional data merging is critical for full-field 3-D shape measurement. 3-D range data patches, acquired either from different sensors or from the same sensor in different viewing angles, have to be merged into a single piece to facilitate future data analysis. In this research, we propose a novel method for 3-D data merging using Holoimage. Similar to the 3-D shape measurement system using a phase-shifting method, Holoimage is a phase-shifting-based computer synthesized fringe image. The virtual projector projects the phase-shifted fringe pattern onto the object, the reflected fringe images are rendered on the screen, and the Holoimage is generated by …

[Ph.D.] Caractérisation Mécanique De Matériaux Fibreux En Vibro-Acoustique, Olivier Doutres Ph.D.

Olivier Doutres Ph.D.

This work deals with modelization and characterization of the mechanical properties of soft fibrous materials used in aeronautic industries. First, the Biot-Allard model and a simplified model dedicated to soft materials are presented. The simplified model, called limp model, assumes that the frame has no bulk stiffness. Being an equivalent fluid model accounting for the the motion of the frame, it has fewer limitations than the usual equivalent fluid model assuming a rigid frame. A criterion is proposed to identify the porous materials for which the limp model can be used : the use of the Biot model is generally …

Introducing New Engineering Students To Mechanical Concepts Through An “Energy Cube” Project, Micheal P. O'Flaherty, Shannon Chance, Fionnuala Farrell, Chris Montague

Shannon M. Chance

The objective of this paper is to describe a problem based learning module, called the “Energy Cube”, offered by Dublin Institute of Technology that is designed to teach mechanical, building services and manufacturing engineering concepts to first year engineering students. The Energy Cube project gives students hands-on experience in areas ranging from heat transfer, lighting and energy efficiency to industrial and product design. In the Energy Cube, students design and construct (using cardboard, clear plastic, and glue) a model of a building that admits as much daylight as possible while being energy efficient and aesthetically pleasing. The students, working in …

Implementation Of A Mems Laboratory Course With Modular, Multidisciplinary Team Projects, John Lee, Stacy H. Gleixner, Tai-Ran Hsu, David W. Parent

David W. Parent

This paper presents the implementation and outcomes of a hands-on laboratory course in microelectromechanical systems (MEMS), co-developed by a multidisciplinary team of faculty from mechanical engineering, electrical engineering, and materials engineering. Central to the design of the course is an emphasis on implementing modules that are able to overcome critical barriers related to (1) diverse academic background from different majors and (2) practical limitations in microfabrication facilities. These points are vital for promoting MEMS education, because they expand the student pool and reach audiences that need a cost-effective way to support instructional laboratory experiences in MEMS without the broader infrastructure …

Phase Error Compensation For A 3-D Shape Measurement System Based On The Phase-Shifting Method, Song Zhang, Peisen S. Huang

Song Zhang

This paper describes a novel phase error compensation method for reducing the measurement error caused by nonsinusoidal waveforms in phase-shifting methods. For 3-D shape measurement systems using commercial video projectors, the nonsinusoidal waveform of the projected fringe patterns as a result of the nonlinear gamma of projectors causes significant phase measurement error and therefore shape measurement error. The proposed phase error compensation method is based on our finding that the phase error due to the nonsinusoidal waveform depends only on the nonlinearity of the projector’s gamma. Therefore, if the projector’s gamma is calibrated and the phase error due to the …

2 - تفکيک دامنة عملکرد ترموستاتهاي دماي داخل ساختمان بر اساس معيارهاي آسايش حرارتي فصلي؛ رهيافتي مؤثر در اقتصاد انرژي, Omidvar Amir, Alireza Zolfaghari, Mehdi Maerefat

Dr Alireza Zolfaghari

No abstract provided.

Numerical Simulation Of The Filling And Curing Stages In Reaction Injection Moulding, Using Ansys Cfx, Rui Igreja

Rui Igreja

Commonly used methods for injection moulding simulation involve a considerable number of simplifications, leading to a significant reduction of the computational effort but, in some cases also to limitations. In this work, Reaction Injection Moulding (RIM) simulations are performed with a minimum of simplifications, by using the general purpose CFD software package Ansys CFX, designed for numerical simulation of fluid flow and heat and mass transfer. The Ansys CFX’s homogeneous multiphase flow model, which is generally considered to be the appropriate choice for modelling free surface flows where the phases are completely stratified and the interface is well defined, is …

Modeling Of The Size Effects On The Behavior Of Metals In Microscale Deformation Processes, Gap-Yong Kim, Jun Ni, Muammer Koc

Gap-Yong Kim

For the accurate analysis and design of microforming process, proper modeling of material behavior at the micro/mesoscale is necessary by considering the size effects. Two size effects are known to exist in metallic materials. One is the “grain size” effect, and the other is the “feature/specimen size” effect. This study investigated the feature/specimen size effect and introduced a scaling model which combined both feature/specimen and grain size effects. Predicted size effects were compared with three separate experiments obtained from previous research: a simple compression with a round specimen, a simple tension with a round specimen, and a simple tension in …

Surface Friction Guiding For Reduced High-Frequency Lateral Vibration Of Moving Media, V. Kartik, Jonathan A. Wickert

Jonathan A. Wickert

The free and forced vibration of a moving medium is examined in an application where distributed friction guiding is used to control lateral position passively. Subambient pressure features formed in the guides intentionally modify the naturally occurring self-pressurized air bearing and increase the contact force between the medium and the guide's surface. These features increase friction to a level beyond that achievable based on the nominal wrap pressure. The moving medium is modeled as a beam that is transported over frictional regions and subjected to prescribed boundary disturbances arising from runout of a supply or take-up roll. For axial transport …

Design And Characteristics Of A Split Hopkinson Pressure Bar Apparatus, Radek Glaser, Jesse Haines, Christopher Knight

Radek Glaser

A Split Hopkinson Pressure Bar Apparatus, also known as Kolsky Bar that is capable of conducting compressive strain rate testing in the approximate ranges from 50 to 10^4 in/in per second was designed as a part of a Senior Design Project. Generally, this device is similar to that first used by Kolsky in 1949. The design of this device is presented here in two stages: 1. Research, design and manufacturing of the Stress Generating System 2. Experimental Part – Testing of the apparatus to obtain necessary data. The present phase of the design was focused mostly on the stress generating …

1 - لزوم بومي سازي استانداردهاي آسايش حرارتي در ساختمان و تأثير آن بر اقتصاد انرژي, Amir Omidvar, Alireza Zolfaghari, Mehdi Maerefat

Dr Alireza Zolfaghari

No abstract provided.

Subsidies For Energy Efficiency Improvements: Theory And Practice, Theodoros Zachariadis

Theodoros Zachariadis

No abstract provided.

"Minimizing Injuries Resulting From Patient Handling In Nursing Home Staff" - A Hazard Control Plan, Vikas Singh

Vikas Singh

A concise hazard control plan for "Minimizing Injuries Resulting from Patient Handling In Nursing Home Staff".

An Experimental Investigation On Semi-Solid Forming Of Micro/Meso-Scale Features, Gap-Yong Kim, Jun Ni, Rhett Mayor, Heesool Kim

Gap-Yong Kim

The potentials of semi-solid forming technology have generated much interest regarding its application in micromanufacturing. This study investigates the feasibility of using semi-solid forming technology to produce parts with micro/meso features. An experimental setup has been developed to study the effects of die/punch temperature, initial solid fraction, punch speed, and workpiece shape on the semi-solid forming process. A part has been produced for a microreactor application and has been analyzed with an optical measurement system for feature formation. The results indicated complex interaction among the process parameters and the material flow, which affected the final pin formation. The punch temperature …

Interface Reorientation During Coherent Phase Transformations, Valery I. Levitas, I. B. Ozsoy, D. L. Preston

Valery I. Levitas

The universal thermodynamic driving force for coherent plane interface reorientation (IR) during first-order phase transformations (PT) in solids is derived. The relation between the rates of IR and interface propagation (IP) and the corresponding driving forces are derived for combined athermal and drag interface friction. The coupled evolution of IR and IP during cubic-tetragonal and tetragonal-orthorhombic PTs under three-dimensional loading is studied. An instability in the interface orientation is shown to have the features of a first-order PT.

Modeling Of The Semi-Solid Material Behavior And Analysis Of Micro-/Mesoscale Feature Forming, Gap-Yong Kim, Muammer Koc, Rhet Mayor, Jun Ni

Gap-Yong Kim

One of the major challenges in simulation of semi-solid forming is characterizing the complex behavior of a material that consists of both solid and liquid phases. In this study, a material model for an A356 alloy in a semi-solid state has been developed for high solid fractions (>0.6) and implemented into a finite element simulation tool to investigate the micro-/mesoscale feature formation during the forming process. Compared to previous stress models, which are limited to expressing the stress dependency on only the strain rate and the temperature (or the solid fraction), the proposed stress model adds the capability of …

Derivation And Application Of A Conserved Orbital Energy For The Inverted Pendulum Bipedal Walking Model, Jerry E. Pratt, Sergey V. Drakunov

Sergey V. Drakunov

Control And Ultrasonic Actuation Of A Gas–Liquid Interface In A Microfluidic Chip, Jie Xu, Daniel Attinger

Daniel Attinger

This paper describes the design and manufacturing of a microfluidic chip, allowing for the actuation of a gas–liquid interface and of the neighboring fluid. The first way to control the interface motion is to apply a pressure difference across it. In this case, the efficiency of three different micro-geometries at anchoring the interface is compared. Also, the critical pressures needed to move the interface are measured and compared to a theoretical result. The second way to control the interface motion is by ultrasonic excitation. When the excitation is weak, the interface exhibits traveling waves, which follow a dispersion equation. At …

Study Of The Wear Behaviour Of Al-4.5% Cu-3.4% Fe In Situ Composite: Effect Of Thermal And Mechanical Processing

A.S. Md Abdul Haseeb

Al-Cu-based MMCs reinforced by Al-Fe intermetallics are investigated for their wear behaviour. The composite (Al-4.5 mass% Cu-3.4 mass% Fe) was produced by solidification processing where the Al-Fe-based intermetallic formed in situ in a matrix of mainly Al-Cu alloy. The effects of thermal and mechanical processing, viz., as-cast condition, solution treatment, aging and hot rolling on the wear behaviour of the composites were examined. The composites were characterized by optical microscopy, SEM, microhardness measurements and X-ray diffraction. The wear behaviour of the composites was studied in a pin-on-disc type wear apparatus. The as-cast in situ composite exhibited the highest wear rate. …

Study Of The Wear Behaviour Of Al-4.5% Cu-3.4% Fe In Situ Composite: Effect Of Thermal And Mechanical Processing, Haseeb Asma

Haseeb ASMA

Al-Cu-based MMCs reinforced by Al-Fe intermetallics are investigated for their wear behaviour. The composite (Al-4.5 mass% Cu-3.4 mass% Fe) was produced by solidification processing where the Al-Fe-based intermetallic formed in situ in a matrix of mainly Al-Cu alloy. The effects of thermal and mechanical processing, viz., as-cast condition, solution treatment, aging and hot rolling on the wear behaviour of the composites were examined. The composites were characterized by optical microscopy, SEM, microhardness measurements and X-ray diffraction. The wear behaviour of the composites was studied in a pin-on-disc type wear apparatus. The as-cast in situ composite exhibited the highest wear rate. …

Creating Sustainable Affordable Housing Stock Using Smart Growth Model, B Bakhtyar

B Bakhtyar

Many low-income people are trapped into paying high rental for low quality housing. It becomes impossible for them to save any down payment for purchasing a home. With the need to house 709,400 units where 38.2% is for low- and low-medium houses in the Ninth Malaysian Plan (9MP), the growing and shifting population is creating demands for new housing in some areas while decreasing demands for new and existing housing in another. The state of Selangor and Kuala Lumpur require 23.7% of new housing units to cater to its growing population in the 9MP. Inflation and other factors have brought …

2 - اولويت بندي و ميزان اثربخشي روشهاي بهينه سازي همزمان شرايط آسايش حرارتي و مصرف انرژي در ساختمان, Amir Omidvar, Mehdi Maerefat, Alireza Zolfaghari

Dr Alireza Zolfaghari

No abstract provided.