Influence Of Spatial Variations Of Railroad Track Stiffness And Material Inclusions On Fatigue Life,
2015
University of Nebraska-Lincoln
Influence Of Spatial Variations Of Railroad Track Stiffness And Material Inclusions On Fatigue Life, Celestin Nkundineza
Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research
Railroad transportation is very important for economic growth and effective maintenance is one critical factor for its economic sustainability. The high repetitive forces from a moving railcar induce cyclic stresses that lead to rail bending and potential deterioration due to fatigue crack initiation and propagation. Previous research for prediction of fatigue life has been done under the assumptions of a uniform track bed and a homogeneous rail. However the spatial variation of the track stiffness is expected to increase the maximum stresses in the rail and, therefore, accelerate the fatigue process. The research described in this dissertation is focused on …
Derivation And Validation Of The Friction, Gravitational, And Air Forces Encountered During Installation Of Fiber Optic Cable,
2015
Minnesota State University - Mankato
Derivation And Validation Of The Friction, Gravitational, And Air Forces Encountered During Installation Of Fiber Optic Cable, Faheed Olayemi Owokoniran
All Graduate Theses, Dissertations, and Other Capstone Projects
This paper presents an introduction to fiber optic cable and the fiber optic communication system. An important phase in the supply of this new technology is to transport the fiber optic cable to the vicinity of service. Cable pulling and cable blowing - laminar flow; piston type - are the two main methods of installing fiber optic cable. Both methods of installation have limiting factors that need to be evaluated in order to perform a successful installation. The limiting factors for laminar type cable blowing are further discussed in this paper. A method was proposed to determine the forces - …
Binder Jet Additive Manufacturing Of Stainless Steel-Hydroxyapatite Bio-Composite,
2015
Minnesota State University - Mankato
Binder Jet Additive Manufacturing Of Stainless Steel-Hydroxyapatite Bio-Composite, Don Suranga Dhanushka Uduwage
All Graduate Theses, Dissertations, and Other Capstone Projects
This study was conducted to create a bio-composite with a porous structure using the binder-jet printing additive manufacturing process. The samples were printed by changing the parameters such as layer thickness, roller speed, sintering time and sintering temperature of the X1-Lab binder jet additive manufacturing printer. The samples were printed 80% stainless steel 316 mixed with 20% Calcium Phosphate Tribasic by volume. Eight experiments were attempted to print according to the fractional factorial design of experiment. The effects of changing parameters on the mechanical properties of the new bio-composite was tested using ASTM E-09 compressive strength standards. The compression testing …
High Temperature Flow Solver For Aerothermodynamics Problems,
2015
University of Kentucky
High Temperature Flow Solver For Aerothermodynamics Problems, Huaibao Zhang
Theses and Dissertations--Mechanical and Aerospace Engineering
A weakly ionized hypersonic flow solver for the simulation of reentry flow is firstly developed at the University of Kentucky. This code is the fluid dynamics module of known as Kentucky Aerothermodynamics and Thermal Response System (KATS). The solver uses a second-order finite volume approach to solve the laminar Navier– Stokes equations, species mass conservation and energy balance equations for flow in chemical and thermal non-equilibrium state, and a fully implicit first-order backward Euler method for the time integration. The hypersonic flow solver is then extended to account for very low Mach number flow using the preconditioning and switch of …
Integrated Sustainability And Resiliency Assessment Methodology For The Design Of Single-Family Residential Structures Subject To Wind And Flood Hazards,
2015
Louisiana State University and Agricultural and Mechanical College
Integrated Sustainability And Resiliency Assessment Methodology For The Design Of Single-Family Residential Structures Subject To Wind And Flood Hazards, Elizabeth Chisolm Matthews
LSU Doctoral Dissertations
Sustainability and resiliency have become important in shaping the criteria in performance-based design objectives in the recent past and will continue to shape future design as climate change impacts and disasters become more prevalent. While much work has been carried out in developing tools to aid in sustainable and resilient performance-based design there is still much work to be done. It is evident that while sustainability and resiliency have mutual advantages there are also inherent conflicts between the two design approaches. Some of the conflict relates to the robustness required of resilient design, which may have higher environmental impacts than …
Automated Conversion Of Text Instructions To Human Motion Animation,
2015
Louisiana State University and Agricultural and Mechanical College
Automated Conversion Of Text Instructions To Human Motion Animation, Ravikumar Vishwanath Chimmalgi
LSU Master's Theses
Text to animation is the conversion of textual instructions to animations following and depicting those instructions. Text to animation is important to fields such as crime scene investigation, military special operations and storytelling where text is utilized. It is also useful for physical therapy where a doctor can factor in disability parameters in the 3D models and determine the safest therapy exercises for patients. It can be used in robotics, where robot assistants can be instructed to perform tasks through text instructions. In this research, a system was created to generate 3D animation of workouts from their textual instructions. An …
Transient Thermoelectric Supercooling: Isosceles Current Pulses From A Response Surface Perspective And The Performance Effects Of Pulse Cooling A Heat Generating Mass,
2015
Michigan Technological University
Transient Thermoelectric Supercooling: Isosceles Current Pulses From A Response Surface Perspective And The Performance Effects Of Pulse Cooling A Heat Generating Mass, Alfred Piggott
Dissertations, Master's Theses and Master's Reports
With increased public interest in protecting the environment, scientists and engineers aim to improve energy conversion efficiency. Thermoelectrics offer many advantages as thermal management technology. When compared to vapor compression refrigeration, above approximately 200 to 600 watts, cost in dollars per watt as well as COP are not advantageous for thermoelectrics. The goal of this work was to determine if optimized pulse supercooling operation could improve cooling capacity or efficiency of a thermoelectric device. The basis of this research is a thermal-electrical analogy based modeling study using SPICE. Two models were developed. The first model, a standalone thermocouple with no …
Computational Study Of Microstructure-Propertymechanism Relations In Ferroic Composites,
2015
Michigan Technological University
Computational Study Of Microstructure-Propertymechanism Relations In Ferroic Composites, Fengde D. Ma
Dissertations, Master's Theses and Master's Reports - Open
Ferroic materials, as notable members of smart materials, have been widely used in applications that perform sensing, actuation and control. The macroscopic property change of ferroic materials may become remarkably large during ferroic phase transition, leading to the fact that the macroscopic properties can be tuned by carefully applying a suitable external field (electric, magnetic, stress). To obtain an enhancement in physical and/or mechanical properties, different kinds of ferroic composites have been fabricated. The properties of a ferroic composite are determined not only by the properties and relative amounts of the constituent phases, but also by the microstructure of individual …
Image-Based Modeling Of Porous Media Using Fem And Lagrangian Particle Tracking,
2015
Louisiana State University and Agricultural and Mechanical College
Image-Based Modeling Of Porous Media Using Fem And Lagrangian Particle Tracking, Paula Cysneiros Sanematsu
LSU Doctoral Dissertations
The study of fundamental flow and transport processes at the pore scale is essential to understanding how the mechanisms affect larger, field-scale, processes that occur in oil and gas recovery, groundwater flow, contaminant transport, and CO2 sequestration. Pore-scale imaging and modeling is one of the techniques used to investigate these fundamental mechanisms. Although extensive development of pore-scale imaging and modeling has occurred recently, some areas still need further advances. In this work, we address two areas: (1) imaging of bulk proppants and proppant-filled fractures under varying loading stress and flow simulation in these systems and (2) nanoparticle (NP) transport modeling …
Magnus Effect In Duct Flow,
2015
The University of Akron
Magnus Effect In Duct Flow, Cameron W. Clarke, Jesse S. Batko, Kenneth W. Smith Jr.
Williams Honors College, Honors Research Projects
The following research paper details the preliminary research carried out by this team. The project was originally conceived to determine if Magnus Lift could be utilized in an unconventional way to assist rockets during takeoff. Several conceptual designs were proposed, but the idea was scrapped when it became apparent that the team would not be able to generate the desired lift without inducing significant amounts of drag and additional weight on a rocket. Instead, the team focused on researching an interesting topic that hasn’t been previously explored: Magnus lift on a cylinder within a duct. An experimental procedure that could …
The Examination Of Stress Corrosion Cracking In High Strength Carbon Steel Through Combined Mechanical-Electrochemical Testing,
2015
University of Akron Main Campus
The Examination Of Stress Corrosion Cracking In High Strength Carbon Steel Through Combined Mechanical-Electrochemical Testing, Jacob Sines
Williams Honors College, Honors Research Projects
Through the analysis of materials and environments seen in industry a better understanding of the fundamentals behind degradation mechanisms can be observed. The scope of this project was to better understand the fundamentals behind the degradation of high strength pipeline steels in a lab setting to simulate an environment seen in industry. Specifically the degradation mechanisms of high and nearly neutral pH stress corrosion cracking were examined in environments that simulated oil and gas pipelines buried in soil. Experimentation was carried out utilizing X65 carbon steel specimen, a Gamry potentiostat, a CORTEST proof ring, a CORTEST slow strain rate machine, …
Parametric Study Of Self-Centering Concentrically-Braced Frames In Response To Earthquakes,
2015
The University Of Akron
Parametric Study Of Self-Centering Concentrically-Braced Frames In Response To Earthquakes, Nicholas F. Roth
Williams Honors College, Honors Research Projects
This research project consisted of the use of computer aided numerical software to test the response of an earthquake resistance system within various buildings when exposed to various design-level earthquakes. This research project is an extension of an existing NSF research project. The relevant questions and investigations of this and the greater project surround the performance of an earthquake resistance system with the intentions of better understanding its abilities and limitations. This project has been aided by Dr. David Roke, the faculty sponsor, in order to perform the research and collect, organize, and analyze the data. This research was performed …
Experimental Validation Of The Calphad Approach Applied To Multi-Principle Element Alloys,
2015
Wright State University
Experimental Validation Of The Calphad Approach Applied To Multi-Principle Element Alloys, Nathan J. Bryant
Browse all Theses and Dissertations
High entropy alloys (HEAs) are a recent area of research in materials science. Their namesake is because their high entropy of mixing due to multiple metallic elements in a near equimolar ratio. The high entropy of mixing is supposed to suppress unwanted, brittle, ordered intermetallic phases, and form a single, randomly mixed solid solution phase. This phenomena makes HEAs a good candidate for structural applications. However, this entropy of mixing may not be enough to suppress all intermetallic phases. For this reason, the CALculation of PHAse Diagrams (CALPHAD) approach is being explored to predict phase equilibrium in HEAs. This study …
Electron-Hole Diffusion Lengths >175 Μm In Solution-Grown Ch3Nh3Pbi3 Single Crystals,
2015
University of Nebraska-Lincoln
Electron-Hole Diffusion Lengths >175 Μm In Solution-Grown Ch3Nh3Pbi3 Single Crystals, Qingfeng Dong, Yanjun Fang, Yuchuan Shao, Padhraic Mulligan, Jie Qiu, Lei Cao, Jinsong Huang
Department of Mechanical and Materials Engineering: Faculty Publications
Long, balanced electron and hole diffusion lengths greater than 100 nanometers in polycrystalline CH3NH3PbI3 are critical for highly efficient perovskite solar cells. We report that the diffusion lengths in CH3NH3PbI3 single crystals grown by a solution-growth method can exceed 175 μm under 1 sun illumination and exceed 3 mm under weak light for both electrons and holes. The internal quantum efficiencies approach 100% in 3 mm-thick single crystal perovskite solar cells under weak light. These long diffusion lengths result from greater carrier mobility, lifetime and dramatically smaller trap densities in …
Multiscale Modeling Of Skeletal Muscle Active Contraction In Relation To Mechanochemical Coupling Of Molecular Motors,
2015
Xi’an Jiaotong University
Multiscale Modeling Of Skeletal Muscle Active Contraction In Relation To Mechanochemical Coupling Of Molecular Motors, Jiangcheng Chen, Xiaodong Zhang, Shengmao Lin, He Wang, Linxia Gu
Department of Mechanical and Materials Engineering: Faculty Publications
In this work, a mathematical model was developed to relate the mechanochemical characterizations of molecular motors with the macroscopic manifestation of muscle contraction. Non-equilibrium statistical mechanics were used to study the collective behavior of myosin molecular motors in terms of the complex conformation change and multiple chemical states in one working cycle. The stochastic evolution of molecular motor probability density distribution during the contraction of sarcomere was characterized by the Fokker-Planck Equation. Quick muscle contraction was demonstrated by the collective dynamic behavior of myosin motors, the muscle contraction force, and the muscle contraction velocity-force relation. Our results are validated against …
Enhanced Pool-Boiling Heat Transfer And Critical Heat Flux On Femtosecond Laser Processed Stainless Steel Surfaces,
2015
University of Nebraska-Lincoln
Enhanced Pool-Boiling Heat Transfer And Critical Heat Flux On Femtosecond Laser Processed Stainless Steel Surfaces, Cory M. Kruse, Troy Anderson, Chris Wilson, Craig Zuhlke, Dennis Alexander, George Gogos, Sidy Ndao
Department of Mechanical and Materials Engineering: Faculty Publications
In this paper, we present an experimental investigation of pool boiling heat transfer on multiscale (micro/nano) functionalized metallic surfaces. Heat transfer enhancement in metallic surfaces is very important for large scale high heat flux applications like in the nuclear power industry. The multiscale structures were fabricated via a femtosecond laser surface process (FLSP) technique, which forms self-organized mound-like microstructures covered by layers of nanoparticles. Using a pool boiling experimental setup with deionized water as the working fluid, both the heat transfer coefficients and critical heat flux were investigated. A polished reference sample was found to have a critical heat flux …
An Agent Based Approach For Simulating Demo Enterprise Models,
2015
Old Dominion University
An Agent Based Approach For Simulating Demo Enterprise Models, Mamadou Seck, Joseph Barjis
Engineering Management & Systems Engineering Faculty Publications
DEMO (design and engineering methodology for organization) is a theoretically grounded methodology for rigorous enterprise modeling. It provides relevant concepts from a construction perspective. As the methodology gains a wider audience, there is a growing interest in simulating DEMO models. Most attempts to develop a simulation approach for enterprise models in general, and the DEMO methodology in particular, are based on process oriented conceptualizations that are typically implementation in a discrete event paradigm. In this paper, we propose a conceptual framework for the translation of DEMO models into an agent based simulation. We will describe the DEMO methodology in some …
Effects Of Gravity On The Acceleration And Pair Statistics Of Inertial Particles In Homogeneous Isotropic Turbulence,
2015
Old Dominion University
Effects Of Gravity On The Acceleration And Pair Statistics Of Inertial Particles In Homogeneous Isotropic Turbulence, H. Parishani, O. Ayala, B. Rosa, L.-P. Wang, W. W. Grabowski
Engineering Technology Faculty Publications
Within the context of heavy particles suspended in a turbulent airflow, we study the effects of gravity on acceleration statistics and radial relative velocity (RRV) of inertial particles. The turbulent flow is simulated by direct numerical simulation (DNS) on a 2563 grid and the dynamics of O(106) inertial particles by the point-particle approach. For particles/droplets with radius from 10 to 60 µm, we found that the gravity plays an important role in particle acceleration statistics: (a) a peak value of particle acceleration variance appears in both the horizontal and vertical directions at a particle Stokes number …
Microindentation Of Bi57in26sn17 Lead-Free Alloy,
2015
University of Kentucky
Microindentation Of Bi57in26sn17 Lead-Free Alloy, Ruiting Zhao
Theses and Dissertations--Chemical and Materials Engineering
There is great need to understand the mechanical properties of lead-free alloys—an alternative of lead-based alloys—to address the environmental problems associated with the use of lead-based materials in microelectronics. In this work, the microstructures of Bi57In26Sn17 lead-free alloy were examined using Optical Microscopy and Energy Dispersive X-ray Spectroscopy analysis. The micro-indentation technique was used to study the mechanical properties of Bi57In26Sn17 lead-free alloy. The experimental results of the hardness and contact modulus were presented and discussed. Local creep during the indentation was observed from the load-displacement curves. The Vickers hardness (HV) increases with the decrease of the indentation depth, suggesting …
Processing And Property Evaluation Of Tungsten-Based Mixed Oxides For Photovoltaics And Optoelectronics,
2015
University of Texas at El Paso
Processing And Property Evaluation Of Tungsten-Based Mixed Oxides For Photovoltaics And Optoelectronics, Mirella Vargas
Open Access Theses & Dissertations
Tungsten Oxide (WO3) films and low-dimensional structures have proven to be promising candidates in the fields of photonics and electronics. WO3 is a well-established n-type semiconductor characterized by unique electrochromic behavior, an ideal optical band gap that permits transparency over a wide spectral range, and high chemical integrity. The plethora of diverse properties endow WO3 to be highly effective in applications related to electrochromism, gas sensing, and deriving economical energy. Compared to the bulk films, a materials system involving WO3 and a related species (elements or metal oxides) offer the opportunity to tailor the electrochromic response, and an overall enhancement …
