Innovation Of Driving Gear Train System For Developer Unit Of Lexmark Home Printers, 2017 University of Tennessee, Knoxville
Innovation Of Driving Gear Train System For Developer Unit Of Lexmark Home Printers, Jay A. Crist, Sarah Gore, Kun Xie, Michael Mixoon
University of Tennessee Honors Thesis Projects
No abstract provided.
Heat Transfer Analysis Of Localized Heat-Treatment For Grade 91 Steel, 2017 Utah State University
Heat Transfer Analysis Of Localized Heat-Treatment For Grade 91 Steel, Jacob D. Walker
All Graduate Theses and Dissertations
Many of the projects utilizing Grade 91 steel are large in scale, therefore it is necessary to assemble on site. The assembly of the major pieces often requires welding in the assembly; welding drastically changes the superior mechanical properties of Grade 91 steel that it was specifically developed for. Therefore, because of the adverse effects of welding on the mechanical properties of Grade 91, it is necessary to do a localized post weld heat treatment.
In this study a localized post weld heat treatment is used to gather experimental data. The data is then used to derive unknown heat transfer ...
Cross-Imaging System Comparison Of Backscatter Coefficient Estimates From A Tissue-Mimicking Material, 2017 University of Wisconsin–Madison
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
Timothy A. Bigelow
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 ...
Experimental Study On Viscosity And Phase Segregation Of Al–Si Powders In Microsemisolid Powder Forming, 2017 Iowa State University
Experimental Study On Viscosity And Phase Segregation Of Al–Si Powders In Microsemisolid Powder Forming, Yufeng Wu, Iver E. Anderson, Thomas A. Lograsso, Gap-Yong Kim
Thomas A. Lograsso
Semisolid powder forming is a promising approach for near-net shape forming of features in macro-/microscale. In this paper, viscosity and phase segregation behavior of Al–Si powders in the semisolid state were studied with back extrusion experiments. The effects of process parameters including shear rate, extrusion ratio, heating time, and precompaction pressure were analyzed using the design of experiments method. The results showed that the effects of shear rate, extrusion, ratio and heating time were statistically significant factors influencing the viscosity. The semisolid state powders showed a shear thinning behavior. Moreover, microstructure analysis of extruded parts indicated severe phase ...
Parallel Framework For Dimensionality Reduction Of Large-Scale Datasets, 2017 Georgia Institute of Technology
Parallel Framework For Dimensionality Reduction Of Large-Scale Datasets, Sai Kiranmayee Samudrala, Jaroslaw Zola, Srinivas Aluru, Baskar Ganapathysubramanian
Dimensionality reduction refers to a set of mathematical techniques used to reduce complexity of the original high-dimensional data, while preserving its selected properties. Improvements in simulation strategies and experimental data collection methods are resulting in a deluge of heterogeneous and high-dimensional data, which often makes dimensionality reduction the only viable way to gain qualitative and quantitative understanding of the data. However, existing dimensionality reduction software often does not scale to datasets arising in real-life applications, which may consist of thousands of points with millions of dimensions. In this paper, we propose a parallel framework for dimensionality reduction of large-scale data ...
Quantifying Organic Solar Cell Morphology: A Computational Study Of Three-Dimensional Maps, 2017 State University of New York at Buffalo
Quantifying Organic Solar Cell Morphology: A Computational Study Of Three-Dimensional Maps, Olga Wodo, John D. Roehling, Adam J. Moulé, Baskar Ganapathysubramanian
Establishing how fabrication conditions quantitatively affect the morphology of organic blends opens the possibility of rationally designing higher efficiency materials; yet such a relationship remains elusive. One of the major challenges stems from incomplete three-dimensional representations of morphology, which is due to the difficulties of performing accurate morphological measurements. Recently, three-dimensional measurements of mixed organic layers using electron tomography with high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) provided maps of morphology with high resolution and detail. Using a simple, yet powerful, computational tool kit, these complex 3D datasets are converted into a set of physically meaningful morphology descriptors. These ...
Computationally Efficient Solution To The Cahn–Hilliard Equation: Adaptive Implicit Time Schemes, Mesh Sensitivity Analysis And The 3d Isoperimetric Problem, Olga Wodo, Baskar Ganapathysubramanian
We present an efficient numerical framework for analyzing spinodal decomposition described by the Cahn–Hilliard equation. We focus on the analysis of various implicit time schemes for two and three dimensional problems. We demonstrate that significant computational gains can be obtained by applying embedded, higher order Runge–Kutta methods in a time adaptive setting. This allows accessing time-scales that vary by five orders of magnitude. In addition, we also formulate a set of test problems that isolate each of the sub-processes involved in spinodal decomposition: interface creation and bulky phase coarsening. We analyze the error fluctuations using these test problems ...
Effect Of Electrolytes On Co-Water Mass Transfer, 2017 Iowa State University
Effect Of Electrolytes On Co-Water Mass Transfer, Haiyang Zhu, Brent H. Shanks, Theodore J. Heindel
Theodore J. Heindel
The influence of various electrolytes such as sulfate, nitrate, and chloride on CO-water mass transfer was investigated in this study. The results indicate that the enhancement in the CO-water volumetric masstransfer coefficient ranged from 1.5 to 4.7 times that of a baseline system without electrolytes, depending on electrolyte type and concentration. For those electrolytes with the same anions, copper-containing electrolytes provided stronger enhancement, whereas for those electrolytes with the same cations, sulfate-containing electrolytes showed stronger enhancement. By measuring both the CO-water volumetric mass-transfer coefficient (kLa) and the mass-transfer coefficient (kL), it was found that the electrolytes inhibit gas ...
A High-Speed X-Ray Detector System For Noninvasive Fluid Flow Measurements, 2017 Iowa State University
A High-Speed X-Ray Detector System For Noninvasive Fluid Flow Measurements, Timothy B. Morgan, Benjamin R. Halls, Terrence R. Meyer, Theodore J. Heindel
Theodore J. Heindel
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 ...
Approximating A Three-Dimensional Fluidized Bed With Two-Dimensional Simulations, 2017 Virginia Polytechnic Institute and State University
Approximating A Three-Dimensional Fluidized Bed With Two-Dimensional Simulations, Mirka Deza, Francine Battaglia, Theodore J. Heindel
Theodore J. Heindel
Fluidized beds can be used to gasify biomass in the production of producer gas, a flammable gas that can replace natural gas in process heating. Modeling these reactors with computational fluid dynamics (CFD) simulations is advantageous when performing parametric studies for design and scale-up. From a computational resource point of view, two-dimensional simulations are easier to perform than three-dimensional simulations, but they may not capture the proper physics. This paper will compare two- and three-dimensional simulations in a 10.2 cm diameter fluidized bed with side air injection to determine when two-dimensional simulations are adequate to capture the bed hydrodynamics ...
A Validation Study For The Hydrodynamics Of Biomass In A Fluidized Bed, 2017 Virginia Polytechnic Institute and State University
A Validation Study For The Hydrodynamics Of Biomass In A Fluidized Bed, Mirka Deza, Francine Battaglia, Theodore J. Heindel
Theodore J. Heindel
Computational modeling of fluidized beds can be used to predict operation of biomass gasifiers after extensive validation with experimental data. The present work focused on computational simulations of a fluidized bed using a multifluid Eulerian-Eulerian model to represent the gas and solid phases as interpenetrating continua. Hydrodynamic results from the simulations were quantitatively compared with X-ray flow visualization studies of a similar bed. It was found that the Gidaspow model can accurately predict the hydrodynamics of the biomass in a fluidized bed. The coefficient of restitution of biomass was fairly high and did not affect the hydrodynamics of the bed ...
Enhancing Co-Water Mass Transfer By Functionalized Mcm41 Nanoparticles, 2017 Iowa State University
Enhancing Co-Water Mass Transfer By Functionalized Mcm41 Nanoparticles, Haiyang Zhu, Brent H. Shanks, Theodore J. Heindel
Theodore J. Heindel
Organic groups are grafted to ∼250-nm-diameter MCM41 nanoparticles with a spherical morphology to enhance the CO-water volumetric mass-transfer coefficient (kLa) for synthesis gas fermentation. The results indicate that (i) ∼250-nm MCM41 nanoparticles show a higher kLa value than large silica particles (1.4 and 7 μm), (ii) surface hydroxyl groups on MCM41 nanoparticles play an important role in mass-transfer enhancement, (iii) organic groups grafted to MCM41 modify the mass-transfer enhancement, and (iv) mercaptan groups grafted to MCM41 show the most mass-transfer enhancement of ∼1.9 times that of no nanoparticle addition. The CO-water mass-transfer enhancement depends on the interaction between ...
Cavitation From A Butterfly Valve: Comparing 3d Simulations To 3d X-Ray Computed Tomography Flow Visualization, 2017 Fisher Controls International, LLC
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
Theodore J. Heindel
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 ...
Model-Based Inversion For Flash Thermography, 2017 Iowa State University
Model-Based Inversion For Flash Thermography, Stephen D. Holland, Brian Schiefelbein
Stephen D. Holland
The thermal image sequences from thermography experiments are blurred by lateral diffusion and therefore hard to interpret. The widely used one-dimensional heat flow model provides a robust interpretation of thickness or delamination from “break time” where lateral diffusion is significant, but is less effective otherwise. As a result, it remains quite common to interpret defects by contrast from the surrounding “acreage” rather than by the intrinsic properties of the defect signal itself.
In this paper, we present an approach for model-based inversion of flash thermography image sequences that attempts to approximately reconstruct the flow or back-surface geometry from the thermal ...
Incorporation Of Composite Defects From Ultrasonic Nde Into Cad And Fe Models, 2017 Iowa State University
Incorporation Of Composite Defects From Ultrasonic Nde Into Cad And Fe Models, Onur Rauf Bingol, Bryan Schiefelbein, Robert J. Grandin, Stephen D. Holland, Adarsh Krishnamurthy
Stephen D. Holland
Fiber-reinforced composites are widely used in aerospace industry due to their combined properties of high strength and low weight. However, owing to their complex structure, it is difficult to assess the impact of manufacturing defects and service damage on their residual life. While, ultrasonic NDE is the preferred method to identify the presence of defects (such as delaminations) in composites, there are no reasonable ways to model the damage and evaluate the structural integrity of composites. Hence, a framework to incorporate flaws and known damage models automatically into a finite element analysis (FEA) of composites will aid in accessing their ...
Adhesion Hysteresis And Its Role In Vibrothermography Crack Heating, 2017 Iowa State University
Adhesion Hysteresis And Its Role In Vibrothermography Crack Heating, Bryan E. Schiefelbein, Tyler Lesthaeghe, Ashraf F. Bastawros, Stephen D. Holland
Stephen D. Holland
Vibrothermography is an NDE inspection which uses vibration to stimulate surface cracks and measure the resultant heat generation. For years, the accepted assumption has been that heat generation in Vibrothermography NDE is due to friction between opposing crack surfaces [1–3]. A frictional mechanism suggests that crack surfaces in sliding shear would generate heat, whereas crack surfaces coming into and out of contact in an opening-closing mode would not, or would generate much less. But cracks heat easily in opening/closing mode and experimental evidence  is not consistent with the prediction that heat generation for shear vibration should be ...
Simple Tester For Measuring Lateral Thermal Diffusivities In Composites, 2017 Iowa State University
Simple Tester For Measuring Lateral Thermal Diffusivities In Composites, Stephen D. Holland, Elizabeth Gregory, Daniel Romero
Stephen D. Holland
Model-based analysis and inversion of thermography data relies on knowledge of thermal diffusivities. Through-thickness diffusivity is readily measured using the flash method . In composite materials, lateral diffusivities may be drastically different from the through-thickness values, but there is no comparable simple and standard approach for measuring those lateral thermal diffusivities. Welch, Heath, and Winfree  proposed a technique based on laser line pulse excitation, but that approach requires a reasonably powerful laser and thermal camera with the concomitant costs and safety requirements. In this presentation, we show a simple and low cost (but not entirely nondestructive) system and method ...
Inspection And Model Based Inversion Of Highly Curved Composite Surfaces With Flash Thermography, 2017 Iowa State University
Inspection And Model Based Inversion Of Highly Curved Composite Surfaces With Flash Thermography, Bryan E. Schiefelbein, Stephen D. Holland
Stephen D. Holland
With the development of advanced aircraft structures and stringent mechanical requirements, robust and reliable inspection methods are needed to ensure safe operation and maximum utilization of the equipment . Aircraft composite parts can exhibit complex geometries and tight curvature, such as leading edges and chines. These curved structures are difficult to inspect for defects, especially where the local curvature is high [2–4]. Pulsed thermography has the potential for rapid inspection of large areas, making it attractive for depot or field inspection of large aircraft parts. When imaging areas of high curvature, there are a number of confounding factors, including ...
Design Of Orbital Maneuvers With Aeroassisted Cubesatellites, 2017 University of Arkansas, Fayetteville
Design Of Orbital Maneuvers With Aeroassisted Cubesatellites, Stephanie Clark
Recent advances within the field of cube satellite technology has allowed for the possible development of a maneuver that utilizes a satellite's Low Earth Orbit (LEO) and increased atmospheric density to effectively use lift and drag to implement a noncoplanar orbital maneuver. Noncoplanar maneuvers typically require large quantities of propellant due to the large delta-v that is required. However, similar maneuvers using perturbing forces require little or no propellant to create the delta-v required. This research reported here studied on the effects of lift on orbital changes, those of noncoplanar types in particular, for small satellites without orbital maneuvering ...
Wime: A Departmental Effort To Improve Recruitment, Retention And Engagement Of Women Students In Mechanical Engineering, Sriram Sundararajan, Theodore J. Heindel, Baskar Ganapathysubramanian, Shankar Subramaniam
The Mechanical Engineering department at Iowa State University started the ‘Women in Mechanical Engineering’ (WiME) program 3 years ago. WiME is a student run, faculty moderated, and department funded program with a three pronged approach to enhance women participation in mechanical engineering – retention, outreach, and recruitment. WiME organizes various social and professional development activities that are intended to • Provide a forum for women to socially interact with faculty and their peers; • Provide students with women role models in engineering and academic professionals thereby helping to develop and sustain a network of professional colleagues and; • Leverage the interests of the WiME ...