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Full-Text Articles in Physics

High Throughput, Automated Prediction Of Focusing Patterns For Inertial Microfluidics, Aditya Kommajosula, Jeong-Ah Kim, Wonhee Lee, Baskar Ganapathysubramanian Jan 2019

High Throughput, Automated Prediction Of Focusing Patterns For Inertial Microfluidics, Aditya Kommajosula, Jeong-Ah Kim, Wonhee Lee, Baskar Ganapathysubramanian

Mechanical Engineering Publications

Visual inspections for identifying focusing points in inertial microfluidic flows are prone to misinterpreting stable locations and focusing shifts in the case of non-trivial focusing patterns. We develop and deploy an approach for automating the calculation of focusing patterns for a general channel geometry, and thereby reduce the dependence on empirical/visual procedures to confirm the presence of stable locations. We utilize concepts from interpolation theory (to represent continuous force-fields using discrete points), and stability theory to identify "basins of attraction" and quantitatively identify stable equilibrium points. Our computational experiments reveal that predicting equilibrium points accurately requires upto ×10-20 times ...


Shape-Design For Stabilizing Micro-Particles In Inertial Microfluidic Flows, Aditya Kommajosula, Daniel Stoecklein, Dino Di Carlo, Baskar Ganapathysubramanian Jan 2019

Shape-Design For Stabilizing Micro-Particles In Inertial Microfluidic Flows, Aditya Kommajosula, Daniel Stoecklein, Dino Di Carlo, Baskar Ganapathysubramanian

Mechanical Engineering Publications

Design of microparticles which stabilize at the centerline of a channel flow when part of a dilute suspension is examined numerically for moderate Reynolds numbers (10≤Re≤80). Stability metrics for particles with arbitrary shapes are formulated based on linear-stability theory. Particle shape is parametrized by a compact, Non-Uniform Rational B-Spline (NURBS)-based representation. Shape-design is posed as an optimization problem and solved using adaptive Bayesian optimization. We focus on designing particles for maximal stability at the channel-centerline robust to perturbations. Our results indicate that centerline-focusing particles are families of characteristic "fish"/"bottle"/"dumbbell"-like shapes, exhibiting fore-aft asymmetry. A ...


Imaging Stress And Magnetism At High Pressures Using A Nanoscale Quantum Sensor, S. Hsieh, P. Bhattacharyya, C. Zu, T. Mittiga, T. J. Smart, F. Machado, B. Kobrin, T. O. Hohn, N. Z. Rui, Mehdi Kamrani, S. Chatterjee, S. Choi, M. Zaletel, V. V. Struzhkin, J. E. Moore, Valery I. Levitas, R. Jeanloz, N. Y. Yao Dec 2018

Imaging Stress And Magnetism At High Pressures Using A Nanoscale Quantum Sensor, S. Hsieh, P. Bhattacharyya, C. Zu, T. Mittiga, T. J. Smart, F. Machado, B. Kobrin, T. O. Hohn, N. Z. Rui, Mehdi Kamrani, S. Chatterjee, S. Choi, M. Zaletel, V. V. Struzhkin, J. E. Moore, Valery I. Levitas, R. Jeanloz, N. Y. Yao

Aerospace Engineering Publications

Pressure alters the physical, chemical and electronic properties of matter. The development of the diamond anvil cell (DAC) enables tabletop experiments to investigate a diverse landscape of high-pressure phenomena ranging from the properties of planetary interiors to transitions between quantum mechanical phases. In this work, we introduce and utilize a novel nanoscale sensing platform, which integrates nitrogen-vacancy (NV) color centers directly into the culet (tip) of diamond anvils. We demonstrate the versatility of this platform by performing diffraction-limited imaging (~600 nm) of both stress fields and magnetism, up to pressures ~30 GPa and for temperatures ranging from 25-340 K. For ...


Current Progress And Future Challenges In Rare-Earth-Free Permanent Magnets, Jun Cui, Matthew J. Kramer, Lin Zhou, Fei Liu, Alexander Gabay, George Hadjipanayis, Balamurugan Balasubramanian, David Sellmyer Jul 2018

Current Progress And Future Challenges In Rare-Earth-Free Permanent Magnets, Jun Cui, Matthew J. Kramer, Lin Zhou, Fei Liu, Alexander Gabay, George Hadjipanayis, Balamurugan Balasubramanian, David Sellmyer

Ames Laboratory Accepted Manuscripts

Permanent magnets (PM) are critical components for electric motors and power generators. Key properties of permanent magnets, especially coercivity and remanent magnetization, are strongly dependent on microstructure. Understanding metallurgical processing, phase stability and microstructural changes are essential for designing and improving permanent magnets. The widely used PM for the traction motor in electric vehicles and for the power generator in wind turbines contain rare earth elements Nd and Dy due to their high maximum energy product. Dy is used to sustain NdFeB's coercivity at higher temperature. Due to the high supply risk of rare earth elements (REE) such as ...


Theoretical And Experimental Investigation Of Forward Spatter Of Blood From A Gunshot, P. M. Comiskey, A. L. Yarin, Daniel Attinger Jun 2018

Theoretical And Experimental Investigation Of Forward Spatter Of Blood From A Gunshot, P. M. Comiskey, A. L. Yarin, Daniel Attinger

Mechanical Engineering Publications

A theoretical model predicting forward blood spatter patterns resulting from a round nose bullet gunshot wound is proposed. The chaotic disintegration of a blood layer located ahead and aside of the bullet is considered in the framework of percolation theory. The size distribution of blood drops is determined, which allows for the prediction of a blood spatter cloud being ejected from the rear side of the target where the bullet exits. Then, droplet trajectories are numerically predicted accounting for gravity and air drag, which is affected by the collective aerodynamic interaction of drops through air. The model predicts the number ...


An Instrument For In Situ Time-Resolved X-Ray Imaging And Diffraction Of Laser Powder Bed Fusion Additive Manufacturing Processes, Nicholas P. Calta, Jenny Wang, Andrew M. Kiss, Aiden A. Martin, Philip J. Depond, Gabriel M. Guss, Vivek Thampy, Anthony Y. Fong, Johanna Nelson Weker, Kevin H. Stone, Christopher J. Tassone, Matthew J. Kramer, Michael F. Toney, Anthony Van Buuren, Manyalibo J. Matthews May 2018

An Instrument For In Situ Time-Resolved X-Ray Imaging And Diffraction Of Laser Powder Bed Fusion Additive Manufacturing Processes, Nicholas P. Calta, Jenny Wang, Andrew M. Kiss, Aiden A. Martin, Philip J. Depond, Gabriel M. Guss, Vivek Thampy, Anthony Y. Fong, Johanna Nelson Weker, Kevin H. Stone, Christopher J. Tassone, Matthew J. Kramer, Michael F. Toney, Anthony Van Buuren, Manyalibo J. Matthews

Ames Laboratory Accepted Manuscripts

In situ X-ray-based measurements of the laser powder bed fusion (LPBF) additive manufacturing process produce unique data for model validation and improved process understanding. Synchrotron X-ray imaging and diffraction provide high resolution, bulk sensitive information with sufficient sampling rates to probe melt pool dynamics as well as phase and microstructure evolution. Here, we describe a laboratory-scale LPBF test bed designed to accommodate diffraction and imaging experiments at a synchrotron X-ray source during LPBF operation. We also present experimental results using Ti-6Al-4V, a widely used aerospace alloy, as a model system. Both imaging and diffraction experiments were carried out at the ...


Tip-Enhanced Raman Scattering Of Dna Aptamers For Listeria Monocytogenes, Siyu He, Hongyuan Li, Carmen L. Gomes, Dmitri V. Voronine May 2018

Tip-Enhanced Raman Scattering Of Dna Aptamers For Listeria Monocytogenes, Siyu He, Hongyuan Li, Carmen L. Gomes, Dmitri V. Voronine

Mechanical Engineering Publications

Optical detection and conformational mapping of aptamers are important for improving medical and biosensing technologies and for better understanding of biological processes at the molecular level. The authors investigate the vibrational signals of deoxyribonucleic acid aptamers specific to Listeria monocytogenes immobilized on gold substrates using tip-enhanced Raman scattering (TERS) spectroscopy and nanoscale imaging. The authors compare topographic and nano-optical signals and investigate the fluctuations of the position-dependent TERS spectra. They perform spatial TERS mapping with 3 nm step size and discuss the limitation of the resulting spatial resolution under the ambient conditions. TERS mapping provides information about the chemical composition ...


An Open-Source Quadrature-Based Population Balance Solver For Openfoam, Alberto Passalacqua, Frédérique Laurent, Ehsan Madadi-Kandjani, Jeffrey C. Heylmun, Rodney O. Fox Feb 2018

An Open-Source Quadrature-Based Population Balance Solver For Openfoam, Alberto Passalacqua, Frédérique Laurent, Ehsan Madadi-Kandjani, Jeffrey C. Heylmun, Rodney O. Fox

Chemical and Biological Engineering Publications

The extended quadrature method of moments (EQMOM) for the solution of population balance equations (PBE) is implemented in the open-source computational fluid dynamic (CFD) toolbox OpenFOAM as part of the OpenQBMM project. The moment inversion procedure was designed (Nguyen et al., 2016) to maximize the number of conserved moments in the transported moment set. The algorithm is implemented in a general structure to allow the addition of other kernel density functions defined on R+, and arbitrary kernels to describe physical phenomena involved in the evolution of the number density function. The implementation is verified with a set of zero-dimensional cases ...


Deformation, Lattice Instability, And Metallization During Solid-Solid Structural Transformations Under General Applied Stress Tensor: Example Of Si I -> Si Ii, Nikolai A. Zarkevich, Hao Chen, Valery I. Levitas, Duane D. Johnson Jan 2018

Deformation, Lattice Instability, And Metallization During Solid-Solid Structural Transformations Under General Applied Stress Tensor: Example Of Si I -> Si Ii, Nikolai A. Zarkevich, Hao Chen, Valery I. Levitas, Duane D. Johnson

Materials Science and Engineering Publications

Density functional theory (DFT) was employed to study the stress-strain behavior, elastic instabilities, and metallization during a solid-solid phase transformation (PT) between semiconducting Si I (cubic A4) and metallic Si II (tetragonal A5 structure) when subjected to a general stress tensor. With normal stresses (σ1, σ2, σ3) acting along ⟨110⟩, ⟨11¯0⟩, and ⟨001⟩, respectively, dictating the simulation cell, we determine combinations of 6 independent stresses that drive a lattice instability for the Si I→Si II PT, and a semiconductor-metal electronic transition. Metallization precedes the structural PT, hence, a stressed Si I can be a metal. Surprisingly, a stress-free ...


Hydrodynamics Of Back Spatter By Blunt Bullet Gunshot With A Link To Bloodstain Pattern Analysis, P. M. Comiskey, A. L. Yarin, Daniel Attinger Jul 2017

Hydrodynamics Of Back Spatter By Blunt Bullet Gunshot With A Link To Bloodstain Pattern Analysis, P. M. Comiskey, A. L. Yarin, Daniel Attinger

Mechanical Engineering Publications

A theoretical model describing the blood spatter pattern resulting from a blunt bullet gunshot is proposed. The predictions are compared to experimental data acquired in the present work. This hydrodynamic problem belongs to the class of the impact hydrodynamics with the pressure impulse generating the blood flow. At the free surface, the latter is directed outwards and accelerated toward the surrounding air. As a result, the Rayleigh-Taylor instability of the flow of blood occurs, which is responsible for the formation of blood drops of different sizes and initial velocities. Thus, the initial diameter, velocity, and acceleration of the atomized blood ...


Characterization Of Chlorella Vulgaris And Chlorella Protothecoides Using Multi-Pixel Photon Counters In A 3d Focusing Optofluidic System, Jonathan B. Vander Wiel, Jonathan D. Mikulicz, Michael R. Boysen, Niloofer Hashemi, Patrick Kalgren, Levi M. Nauman, Seth J. Baetzold, Gabrielle G. Powell, Qing He, Nicole Nastaran Hashemi Jan 2017

Characterization Of Chlorella Vulgaris And Chlorella Protothecoides Using Multi-Pixel Photon Counters In A 3d Focusing Optofluidic System, Jonathan B. Vander Wiel, Jonathan D. Mikulicz, Michael R. Boysen, Niloofer Hashemi, Patrick Kalgren, Levi M. Nauman, Seth J. Baetzold, Gabrielle G. Powell, Qing He, Nicole Nastaran Hashemi

Mechanical Engineering Publications

Analysis of microparticle size and fluorescence intensity can be used to classify microparticles. We designed and fabricated an optofluidic system that characterizes microparticles, including fluorescent microparticles and microalgae. A new type of multi-pixel photon counter (MPPC) was employed to miniaturize the device, lower its power consumption, and make it insensitive to magnetic fields. The system uses a 635 nm laser for excitation of the microparticles' fluorescence. The scattered light from the fluorescent microparticles, as well as Chlorella vulgaris and Chlorella protothecoides, were measured. Additionally, we analyzed the width and height of the measured signals generated as a result of microparticles ...


Big Area Additive Manufacturing Of High Performance Bonded Ndfeb Magnets, Li Ling, Angelica Tirado, I. C. Nlebedim, Orlando Rios, Brian Post, Vlastimil Kunc, R. R. Lowden, Edgar Lara-Curzio, Magnet Applications, Inc., Thomas A. Lograsso, M. Parans Paranthaman Oct 2016

Big Area Additive Manufacturing Of High Performance Bonded Ndfeb Magnets, Li Ling, Angelica Tirado, I. C. Nlebedim, Orlando Rios, Brian Post, Vlastimil Kunc, R. R. Lowden, Edgar Lara-Curzio, Magnet Applications, Inc., Thomas A. Lograsso, M. Parans Paranthaman

Ames Laboratory Publications

Additive manufacturing allows for the production of complex parts with minimum material waste, offering an effective technique for fabricating permanent magnets which frequently involve critical rare earth elements. In this report, we demonstrate a novel method - Big Area Additive Manufacturing (BAAM) - to fabricate isotropic near-net-shape NdFeB bonded magnets with magnetic and mechanical properties comparable or better than those of traditional injection molded magnets. The starting polymer magnet composite pellets consist of 65 vol% isotropic NdFeB powder and 35 vol% polyamide (Nylon-12). The density of the final BAAM magnet product reached 4.8 g/cm3, and the room temperature magnetic properties ...


Prediction Of Blood Back Spatter From A Gunshot In Bloodstain Pattern Analysis, P. M. Comiskey, A. L. Yarin, S. Kim, Daniel Attinger Aug 2016

Prediction Of Blood Back Spatter From A Gunshot In Bloodstain Pattern Analysis, P. M. Comiskey, A. L. Yarin, S. Kim, Daniel Attinger

Mechanical Engineering Publications

A theoretical model for predicting and interpreting blood-spatter patterns resulting from a gunshot wound is proposed. The physical process generating a backward spatter of blood is linked to the Rayleigh-Taylor instability of blood accelerated toward the surrounding air, allowing the determination of the initial distribution of drop sizes and velocities. Then the motion of many drops in air is considered with governing equations accounting for gravity and air drag. Based on these equations, a numerical solution is obtained. It predicts the atomization process, the trajectories of the back-spatter drops of blood from the wound to the ground, the impact angle ...


Thermodynamics And Historical Relevance Of A Jetting Thermometer Made Of Chinese Zisha Ceramic, Vincent Lee, Daniel Attinger Jul 2016

Thermodynamics And Historical Relevance Of A Jetting Thermometer Made Of Chinese Zisha Ceramic, Vincent Lee, Daniel Attinger

Mechanical Engineering Publications

Following a recent trend of scientific studies on artwork, we study here the thermodynamics of a thermometer made of zisha ceramic, related to the Chinese tea culture. The thermometer represents a boy who “urinates” shortly after hot water is poured onto his head. Long jetting distance is said to indicate that the water temperature is hot enough to brew tea. Here, a thermodynamic model describes the jetting phenomenon of that pee-pee boy. The study demonstrates how thermal expansion of an interior air pocket causes jetting. A thermodynamic potential is shown to define maximum jetting velocity. Seven optimization criteria to maximize ...


High Aspect Ratio Carbon Nanotube Membranes Decorated With Pt Nanoparticle Urchins For Micro Underwater Vehicle Propulsion Via H2o2 Decomposition, Kevin Marr, Bolin Chen, Eric J. Mootz, Jason Geder, Marius Pruessner, Brian J. Melde, Richard R. Vanfleet, Igor L. Medintz, Brian D. Iverson, Jonathan C. Claussen Jan 2015

High Aspect Ratio Carbon Nanotube Membranes Decorated With Pt Nanoparticle Urchins For Micro Underwater Vehicle Propulsion Via H2o2 Decomposition, Kevin Marr, Bolin Chen, Eric J. Mootz, Jason Geder, Marius Pruessner, Brian J. Melde, Richard R. Vanfleet, Igor L. Medintz, Brian D. Iverson, Jonathan C. Claussen

Mechanical Engineering Publications

The utility of unmanned micro underwater vehicles (MUVs) is paramount for exploring confined spaces, but their spatial agility is often impaired when maneuvers require burst-propulsion. Herein we develop high-aspect ratio (150:1), multiwalled carbon nanotube microarray membranes (CNT-MMs) for propulsive, MUV thrust generation by the decomposition of hydrogen peroxide (H2O2). The CNT-MMs are grown via chemical vapor deposition with diamond shaped pores (nominal diagonal dimensions of 4.5 × 9.0 μm) and subsequently decorated with urchin-like, platinum (Pt) nanoparticles via a facile, electroless, chemical deposition process. The Pt-CNT-MMs display robust, high catalytic ability with an effective activation ...


Utilizing Wide Band Gap, High Dielectric Constant Nanoparticles As Additives In Organic Solar Cells, Ryan S. Gebhardt, Pengfei Du, Akshit Peer, Mitch Rock, Michael R. Kessler, Rana Biswas, Baskar Ganapathysubramanian, Sumit Chaudhary Jan 2015

Utilizing Wide Band Gap, High Dielectric Constant Nanoparticles As Additives In Organic Solar Cells, Ryan S. Gebhardt, Pengfei Du, Akshit Peer, Mitch Rock, Michael R. Kessler, Rana Biswas, Baskar Ganapathysubramanian, Sumit Chaudhary

Mechanical Engineering Publications

We experimentally and theoretically investigate the effects of utilizing BaTiO3 nanoparticles as additives in polythiophene/fullerene solar cells. BaTiO3 nanoparticles were chosen because of their multifaceted potential for increasing exciton dissociation (due to their high dielectric constant) and light scattering. To achieve stable suspensions for device fabrication, the nanoparticles were functionalized with organic ligands. Solar cells fabricated in air showed ∼40% enhancement in the photocurrent primarily due to string-like aggregates of functionalized BaTiO3 particles that increase light absorption without hindering charge collection. Solar cells fabricated in an inert atmosphere yielded overall more efficient devices, but the string-like aggregates were absent ...


High-Speed 3d Shape Measurement With Fiber Interference, Beiwen Li, Pan Ou, Song Zhang Aug 2014

High-Speed 3d Shape Measurement With Fiber Interference, Beiwen Li, Pan Ou, Song Zhang

Mechanical Engineering Conference Presentations, Papers, and Proceedings

This paper presents a miniaturized fringe projection system that only uses two fibers to potentially achieve superfast (e.g., MHz to GHz) 3D shape measurement speeds. The proposed method uses two optical fibers that carry the same wavelength of laser light with polarization and phase information properly modulated to generate high-quality sinusoidal fringe patterns through interference. The high-speed phase shifting is achieved by employing a high-speed Lithium Niobate (LN) electrooptic phase modulator. Since only two optical fibers are used to generate sinusoidal patterns, the system has a great potential of miniaturization for applications where the sensor size is critical (e ...


How Do Evaporating Thin Films Evolve? Unravelling Phase-Separation Mechanisms During Solvent-Based Fabrication Of Polymer Blends, Olga Wodo, Baskar Ganapathysubramanian Jan 2014

How Do Evaporating Thin Films Evolve? Unravelling Phase-Separation Mechanisms During Solvent-Based Fabrication Of Polymer Blends, Olga Wodo, Baskar Ganapathysubramanian

Mechanical Engineering Publications

Solvent-based fabrication is a flexible and affordable approach to manufacture polymer thin films. The properties of products made from such films can be tailored by the internal organization (morphology) of the films. However, a precise knowledge of morphology evolution leading to the final film structure remains elusive, thus limiting morphology control to a trial and error approach. In particular, understanding when and where phases are formed, and how they evolve would provide rational guidelines for more rigorous control. Here, we identify four modes of phase formation and subsequent propagation within the thinning film during solvent-based fabrication. We unravel the origin ...


Characterizing Acoustic Fluidized Bed Hydrodynamics Using X-Ray Computed Tomography, David R. Escudero, Theodore J. Heindel Jul 2013

Characterizing Acoustic Fluidized Bed Hydrodynamics Using X-Ray Computed Tomography, David R. Escudero, Theodore J. Heindel

Mechanical Engineering Conference Presentations, Papers, and Proceedings

Fluidized bed reactors are important assets of many industrial applications because they provide uniform temperature distributions, low pressure drops, and high heat/mass rates. Characterizing the hydrodynamics of a fluidized bed is important to better understand the behavior of these multiphase flow systems. The hydrodynamic behavior in a cold flow 3D fluidized bed, with and without acoustic intervention, using X-ray computed tomography is investigated in this study. Experiments are carried out in a 10.2 cm ID fluidized bed filled with glass beads, with material density of 2600 kg/m3 and particle size ranges between 212–600 μm. In ...


A High-Speed X-Ray Detector System For Noninvasive Fluid Flow Measurements, Timothy B. Morgan, Benjamin R. Halls, Terrence R. Meyer, Theodore J. Heindel Jul 2013

A High-Speed X-Ray Detector System For Noninvasive Fluid Flow Measurements, Timothy B. Morgan, Benjamin R. Halls, Terrence R. Meyer, Theodore J. Heindel

Mechanical Engineering Conference Presentations, Papers, and Proceedings

The opaque nature of many multiphase flows has long posed a significant challenge to the visualization and measurement of desired characteristics. To overcome this difficulty, X-ray imaging, both in the form of radiography and computed tomography, has been used successfully to quantify various multiphase flow phenomena. However, the relatively low temporal resolution of typical X-ray systems limit their use to moderately slow flows and time-average values. This paper discusses the development of an X-ray detection system capable of high-speed radiographic imaging that can be used to visualize multiphase flows. Details of the hardware will be given and then applied to ...


Chip Segmentation In Machining: A Study Of Deformation Localization Characteristics In Ti6al4v, Abhijit Chandra, Pavan Karra, Adam Bragg, Jie Wang, Gap-Yong Kim Jun 2013

Chip Segmentation In Machining: A Study Of Deformation Localization Characteristics In Ti6al4v, Abhijit Chandra, Pavan Karra, Adam Bragg, Jie Wang, Gap-Yong Kim

Mechanical Engineering Conference Presentations, Papers, and Proceedings

Chip segmentation by deformation localization is an important process in a certain range of velocities and might be desirable in reducing cutting forces and by improving chips’ evacuation, whereas few studies of practical criteria to calculate shear band spacing are available in literature. This paper extends nonlinear dynamics model for chip segmentation by allowing time varying orientation of the shear plane that are pronounced in strain hardening materials. The model extends the non-linear dynamics approach with additional state variables to the Burns and Davies approach. The model is simulated numerically to predict the shear bands of the chip. The numerical ...


Cross-Imaging System Comparison Of Backscatter Coefficient Estimates From A Tissue-Mimicking Material, Kibo Nam, Ivan M. Rosado-Mendez, Lauren A. Wirtzfeld, Viksit Kumar, Ernest L. Madsen, Goutam Ghoshal, Alexander D. Pawlicki, Michael L. Oelze, Roberto J. Lavarello, Timothy A. Bigelow, James A. Zagzebski, William D. O'Brien Jr., Timothy J. Hall Sep 2012

Cross-Imaging System Comparison Of Backscatter Coefficient Estimates From A Tissue-Mimicking Material, Kibo Nam, Ivan M. Rosado-Mendez, Lauren A. Wirtzfeld, Viksit Kumar, Ernest L. Madsen, Goutam Ghoshal, Alexander D. Pawlicki, Michael L. Oelze, Roberto J. Lavarello, Timothy A. Bigelow, James A. Zagzebski, William D. O'Brien Jr., Timothy J. Hall

Electrical and Computer Engineering Publications

A key step toward implementing quantitative ultrasound techniques in a clinical setting is demonstrating that parameters such as the ultrasonic backscatter coefficient (BSC) can be accurately estimated independent of the clinical imaging system used. In previous studies, agreement in BSC estimates for well characterized phantoms was demonstrated across different laboratory systems. The goal of this study was to compare the BSC estimates of a tissue mimicking sample measured using four clinical scanners, each providing RF echo data in the 1-15 MHz frequency range. The sample was previously described and characterized with single-element transducer systems. Using a reference phantom for analysis ...


Acoustic Field Effects On Minimum Fluidization Velocity In A 3d Fluidized Bed, David R. Escudero, Theodore J. Heindel Jul 2012

Acoustic Field Effects On Minimum Fluidization Velocity In A 3d Fluidized Bed, David R. Escudero, Theodore J. Heindel

Mechanical Engineering Conference Presentations, Papers, and Proceedings

Fluidized beds are used in a variety of process industries because they provide uniform temperature distributions, low pressure drops, and high heat/mass rates. Minimum fluidization velocity is an important factor in understanding the hydrodynamic behavior of fluidized beds, and this characteristic may be modified through high frequency (sound) vibrations. The effects caused by sound wave frequency on the minimum fluidization velocity in a 3D fluidized bed are investigated in this study. Experiments are carried out in a 10.2 cm ID cold flow fluidized bed filled with glass beads with material density of 2600 kg/m3, and particles ...


The Morphotropic Phase Boundary In The (1-X)Pbzro3–X[0.3bi(Zn1/2ti1/2)O3–0.7pbtio3] Perovskite Solid Solution, T. Sareein, W. Hu, Xiaoli Tan, R. Yimnirun Jan 2012

The Morphotropic Phase Boundary In The (1-X)Pbzro3–X[0.3bi(Zn1/2ti1/2)O3–0.7pbtio3] Perovskite Solid Solution, T. Sareein, W. Hu, Xiaoli Tan, R. Yimnirun

Materials Science and Engineering Publications

Ceramics in the (1-x)PbZrO3–x[0.3Bi(Zn1/2Ti1/2)O3–0.7PbTiO3] solid solution system with 0.48  x  0.56 were investigated. A morphotropic phase boundary separating rhombohedral and tetragonal perovskite phases was identified at x = 0.52. This composition displays the maximum remanent polarization Pr of 40.7 μC/cm2 and the best piezoelectric coefficient d33 of 311 pC/N in the pseudo-binary system. However, the Curie temperature Tc for this MPB composition is 291 °C, much lower than initially expected.


Cavitation From A Butterfly Valve: Comparing 3d Simulations To 3d X-Ray Computed Tomography Flow Visualization, Graham Brett, Marc Riveland, Terrence C. Jensen, Theodore J. Heindel Jul 2011

Cavitation From A Butterfly Valve: Comparing 3d Simulations To 3d X-Ray Computed Tomography Flow Visualization, Graham Brett, Marc Riveland, Terrence C. Jensen, Theodore J. Heindel

Mechanical Engineering Conference Presentations, Papers, and Proceedings

Flow control valves may experience localized cavitation when the local static pressure drops to the liquid vapor pressure. Localized damage to the valve and surrounding area can occur when the vapor cavity collapses. Valve designs that reduce cavitation are based on empirical evidence and accumulated experience, but there are still considerable cavitation problems in industry. Valve designers may use computational fluid dynamics (CFD) to simulate cavitation in flow control valves, but model validation is challenging because there are limited data of local cavitation from the valve surface. Typically, the intensity of cavitation in a control valve is inferred from measurements ...


A Method To Quantify Mixing In A Two Component Fluidized Bed, Norman K. Keller, Theodore J. Heindel Aug 2010

A Method To Quantify Mixing In A Two Component Fluidized Bed, Norman K. Keller, Theodore J. Heindel

Mechanical Engineering Conference Presentations, Papers, and Proceedings

Fluidized bed technology can be used for pyrolysis and gasification of solid fuel particles such as biomass, which is important to industry because of its potential as an alternative for petroleum-based fuels. To efficiently utilize a fluidized bed reactor it is necessary, among other factors, to investigate the mixing and segregation behavior of the fuel particles with the bed material. In order to characterize the material distribution, a technique to visualize the biomass inside a fluidized bed reactor has been developed using X-ray computed tomography (CT) scans. This paper presents an image analysis procedure that can be used to quantify ...


Fast-Framing Ballistic Imaging Of Velocity In An Aerated Spray, David Sedarsky, James Gord, Campbell Carter, Terrence R. Meyer, Mark Linne Sep 2009

Fast-Framing Ballistic Imaging Of Velocity In An Aerated Spray, David Sedarsky, James Gord, Campbell Carter, Terrence R. Meyer, Mark Linne

Mechanical Engineering Publications

We describe further development of ballistic imaging adapted for the liquid core of an atomizing spray. To fully understand spray breakup dynamics, one must measure the velocity and acceleration vectors that describe the forces active in primary breakup. This information is inaccessible to most optical diagnostics, as the signal is occluded by strong scattering in the medium. Ballistic imaging mitigates this scattering noise, resolving clean shadowgram-type images of structures within the dense spray region. We demonstrate that velocity data can be extracted from ballistic images of a spray relevant to fuel-injection applications, by implementing a simple, targeted correlation method for ...


X-Ray Particle Tracking Velocimetry In Fluidized Beds, Joshua B. Drake, Lie Tang, Theodore J. Heindel Aug 2009

X-Ray Particle Tracking Velocimetry In Fluidized Beds, Joshua B. Drake, Lie Tang, Theodore J. Heindel

Mechanical Engineering Conference Presentations, Papers, and Proceedings

Fluidized beds are commonly found in the chemical and energy processing industries because of their low pressure drop, uniform temperature distribution, and high heat transfer rates. For example, in biomass gasification, biomass particles are injected into a heated bubbling bed of inert material (typically refractory sand) that volatilizes to form a flammable gas. However, the movement of the biomass particle through the bubbling bed is difficult to quantify because the systems are opaque. This paper describes X-ray particle tracking velocimetry (XPTV) applied to fluidized beds, where X-ray flow visualization is used to track the location of a single fabricated tracer ...


Repeatability Of Gas Holdup In A Fluidized Bed Using X-Ray Computed Tomography, Joshua B. Drake, Theodore J. Heindel Aug 2009

Repeatability Of Gas Holdup In A Fluidized Bed Using X-Ray Computed Tomography, Joshua B. Drake, Theodore J. Heindel

Mechanical Engineering Conference Presentations, Papers, and Proceedings

Characterizing the hydrodynamics in fluidized beds is important to many processes from producing biofuels to coating pharmaceuticals. X-ray computed tomography (CT) can quantify local time-averaged phase fractions in multiphase systems that are highly dynamic, like fluidized beds. This paper describes the calibration methods used to produced CT images of a 15.24 cm diameter fluidized bed, how in-house software used these CTs to calculate gas holdup, and how well multiple CTs of a dynamic fluidized bed produced repeatable results while varying bed material and superficial gas velocities. It was concluded there is a very high degree of repeatability using the ...


Modeling A Biomass Fluidizing Bed With Side Port Air Injection, Mirka Deza, Francine Battaglia, Theodore J. Heindel Aug 2009

Modeling A Biomass Fluidizing Bed With Side Port Air Injection, Mirka Deza, Francine Battaglia, Theodore J. Heindel

Mechanical Engineering Conference Presentations, Papers, and Proceedings

Fluidized beds are used to gasify materials such as coal or biomass in the production of producer gas. Modeling these reactors using computational fluid dynamics is advantageous when performing parametric studies for design and scale-up. While two-dimensional simulations are easier to perform than three-dimensional simulations, they may not capture the proper physics. This paper compares two- and three-dimensional simulations with experiments for a reactor geometry with side port air injection. The side port is located within the bed region so that the injected air can help promote mixing. Of interest in this study is validating the hydrodynamics of fluidizing biomass ...