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High Fidelity Cfd Modeling Of Natural Ventilation In A Solar House, Mirka Deza, Baskar Ganapathysubramanian, Shan He, Ulrike Passe 2017 Iowa State University

High Fidelity Cfd Modeling Of Natural Ventilation In A Solar House, Mirka Deza, Baskar Ganapathysubramanian, Shan He, Ulrike Passe

Ulrike Passe

Natural ventilation is an important factor in the design of sustainable buildings; it has the potential to improve air quality, while providing thermal comfort at reduced energy costs. Computational fluid dynamics (CFD) simulations provide comprehensive information on the internal flow pattern and can be used as a design tool. The present work offers insight of natural ventilation in a fully functional building, namely, the solar facility Interlock House in Iowa. Ventilation in the house is studied during summer months with some of its furniture included. The results show quantitative agreement between numerical simulations and experiments of vertical temperature profiles for ...


Inspection And Model Based Inversion Of Highly Curved Composite Surfaces With Flash Thermography, Bryan E. Schiefelbein, Stephen D. Holland 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 [1]. 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 ...


Ultrasound Scatter In Heterogeneous 3d Microstructures, Brady Engle, Ronald A. Roberts, Robert Grandin 2017 Iowa State University

Ultrasound Scatter In Heterogeneous 3d Microstructures, Brady Engle, Ronald A. Roberts, Robert Grandin

Robert Grandin

This paper reports on a computational study of ultrasound propagation in heterogeneous metal microstructures. Random spatial fluctuations in elastic properties over a range of length scales relative to ultrasound wavelength can give rise to scatter-induced attenuation, backscatter noise, and phase front aberration. It is of interest to quantify the dependence of these phenomena on the microstructure parameters, for the purpose of quantifying deleterious consequences on flaw detectability, and for the purpose of material characterization. Valuable tools for estimation of microstructure parameters (e.g. grain size) through analysis of ultrasound backscatter have been developed based on approximate weak-scattering models. While useful ...


Surrogate Modeling Of Ultrasonic Testing Simulations Using Variable-Fidelity Models And Data-Driven Methods, Robert Grandin, Leifur Leifsson 2017 Iowa State University

Surrogate Modeling Of Ultrasonic Testing Simulations Using Variable-Fidelity Models And Data-Driven Methods, Robert Grandin, Leifur Leifsson

Robert Grandin

Ultrasonic testing (UT) is used to detect internal flaws in materials or to characterize material properties [1]. Computational simulations are an important part of the UT process. Having fast surrogate models for ultrasonic testing (UT) simulations is key for inverse analysis and model-assisted probability of detection (MAPOD) in the field of nondestructive evaluation. In fact, it is impractical to perform the aforementioned tasks in a timely manner using current simulation models directly. Fast surrogate models can make these processes computationally tractable. This paper presents investigations of using surrogate modeling techniques to create fast approximate models of UT simulator responses. In ...


Validation Of Utsim2, A New Ultrasonic Simulation Package, Robert Grandin, Timothy Gray 2017 Iowa State University

Validation Of Utsim2, A New Ultrasonic Simulation Package, Robert Grandin, Timothy Gray

Robert Grandin

The Center for NDE (CNDE) at Iowa State University has a long history of developing physics models for NDE and packaging these models into simulation tools which make the modeling capabilities accessible to CNDE’s industrial sponsors. Recent work at CNDE has led to the development of a new ultrasonic simulation package, UTSim2, which aims to continue this tradition of supporting industrial application of CNDE models. In order to meet this goal, UTSim2 has been designed as an extensible software package which can support previously-developed physics models as well as future models yet to be developed. Initial work has focused ...


Dynamic Amplification Factors For Railway Turnout Bearers In Switches And Crossings, Sakdirat Kaewunruen, Chayut Ngamkhanong, Rims Janeliukstis, Ruilin You 2017 University of Birmingham

Dynamic Amplification Factors For Railway Turnout Bearers In Switches And Crossings, Sakdirat Kaewunruen, Chayut Ngamkhanong, Rims Janeliukstis, Ruilin You

Sakdirat Kaewunruen


Railway infrastructure is nonlinear by nature, scientifically proven by its behav-iours, geometry and alignment, wheel-rail forces and operational parameters such as tractive efforts. It is often found that most train-turnout interaction models do not consider the time dependent ballast degradation. Such ballast degradation later causes differential settlement and aggravates impact forces acting on partial and unsupported sleepers and bearers. Fur-thermore, localised ballast breakages underneath any railseat increase the likelihood of cen-tre-bound cracks in railway sleepers and bearers due to the unbalanced support. This paper presents a numerical simulation of a standard-gauge concrete bearer at crossing panel, tak-ing into account the ...


Instructional Strategies In Diagram-Based Itss: Lessons Learned From Two Tutoring Systems, Enruo Guo, Stephen B. Gilbert 2017 Iowa State University

Instructional Strategies In Diagram-Based Itss: Lessons Learned From Two Tutoring Systems, Enruo Guo, Stephen B. Gilbert

Stephen B. Gilbert

Unlike text-based input to an intelligent tutoring system, a diagram is perceived as a whole state; the operation sequence is less important. Traditional step-wise coaching is not as appropriate in diagram-based intelligent tutoring systems (DITS). From two previous tutoring systems, StaticsTutor and Thermo Cycle Tutor, we propose cross-domain pedagogical guidelines for DITS. In particular, instruction needs to be mapped to a hierarchical understanding of the diagram, where each level focuses on different characteristics of the drawing. Also, instruction needs to address conceptual knowledge and procedure expertise separately. Some practical suggestions are described to achieve these goals, such as 1) different ...


Full Wave Modeling Of Ultrasonic Scattering Using Nystrom Method For Nde Applications, Praveen Gurrala, Kun Chen, Jiming Song, Ron Roberts 2017 Iowa State University

Full Wave Modeling Of Ultrasonic Scattering Using Nystrom Method For Nde Applications, Praveen Gurrala, Kun Chen, Jiming Song, Ron Roberts

Jiming Song

Approximate methods for ultrasonic scattering like the Kirchhoff approximation and the geometrical theory of diffraction (GTD) can deliver fast solutions with relatively small computational resources compared to accurate numerical methods. However, these models are prone to inaccuracies in predicting scattered fields from defects that are not very large compared to wavelength. Furthermore, they do not take into account physical phenomena like multiple scattering and surface wave generation on defects. Numerical methods like the finite element method (FEM) and the boundary element method (BEM) can overcome these limitations of approximate models. Commercial softwares such as Abaqus FEA and PZFlex use FEM ...


Advanced Text Analytics And Machine Learning Approach For Document Classification, Chaitanya Anne 2017 University of New Orleans

Advanced Text Analytics And Machine Learning Approach For Document Classification, Chaitanya Anne

University of New Orleans Theses and Dissertations

Text classification is used in information extraction and retrieval from a given text, and text classification has been considered as an important step to manage a vast number of records given in digital form that is far-reaching and expanding. This thesis addresses patent document classification problem into fifteen different categories or classes, where some classes overlap with other classes for practical reasons. For the development of the classification model using machine learning techniques, useful features have been extracted from the given documents. The features are used to classify patent document as well as to generate useful tag-words. The overall objective ...


Uncertainty Quantification Of Turbulence Model Closure Coefficients On Openfoam And Fluent For Mildly Separated Flows, Ike Witte 2017 Washington University in St Louis

Uncertainty Quantification Of Turbulence Model Closure Coefficients On Openfoam And Fluent For Mildly Separated Flows, Ike Witte

Engineering and Applied Science Theses & Dissertations

In this thesis, detailed uncertainty quantification studies focusing on the closure coefficients of eddy-viscosity turbulence models for several flows using two CFD solvers have been performed. Three eddy viscosity turbulence models considered are: the one-equation Spalart-Allmaras (SA) model, the two-equation Shear Stress Transport (SST) k-ω model, and the one-equation Wray-Agarwal (WA) model. OpenFOAM and ANSYS Fluent are used as flow solvers. Uncertainty quantification analyses are performed for subsonic flow over a flat plate, subsonic flow over a backward-facing step, and transonic flow past an axisymmetric bump. In the case of flat plate, coefficients of pressure, lift, drag, and skin friction ...


An Exact Analysis For Four-Order Acousto-Optic Bragg Diffraction Which Incorporates Both Incident Light Angle And Sound Frequency Dependencies, Adeyinka Sunday Ademola 2017 University of Texas at Tyler

An Exact Analysis For Four-Order Acousto-Optic Bragg Diffraction Which Incorporates Both Incident Light Angle And Sound Frequency Dependencies, Adeyinka Sunday Ademola

Electrical Engineering Theses

This thesis extends the prior work which produced an exact solution to the four-order acousto-optic (AO) Bragg cell with assumed fixed center frequency and with exact Bragg angle incident light. The extension predicts the model that incorporates the dependencies of both the input angle of light and the sound frequency. Specifically, a generalized 4th order linear differential equation (DE), is developed from a simultaneous analysis of four coupled AO system of DEs. Through standard methods, the characteristic roots, which requires solving a quartic equation, is produced. Subsequently, a derived system of homogeneous solutions, which absorbs the roots obtained using ...


Target Detection With Neural Network Hardware, Hollis Bui, Garrett Massman, Nikolas Spangler, Jalen Tarvin, Luke Bechtel, Kevin Dunn, Shawn Bradford 2017 University of Tennessee, Knoxville

Target Detection With Neural Network Hardware, Hollis Bui, Garrett Massman, Nikolas Spangler, Jalen Tarvin, Luke Bechtel, Kevin Dunn, Shawn Bradford

University of Tennessee Honors Thesis Projects

No abstract provided.


Generation And Analysis Of A Social Network: Hamlet, Preston Evans 2017 University of Arkansas, Fayetteville

Generation And Analysis Of A Social Network: Hamlet, Preston Evans

Computer Science and Computer Engineering Undergraduate Honors Theses

This paper examines the generation and analysis of a social network produced from Shakespeare’s play Hamlet. An XML file of Hamlet was parsed to extract the characters within the play and also identify when the characters appeared within the same scene. After parsing the speakers and the connections between characters, a network graph was generated that displayed all the characters in Hamlet, represented by nodes, and edges that represented the connections between characters as measured by their scene co-appearance. The results of the network graph were then compared to a published social network for Hamlet created by hand. The ...


Simulating Foodborne Pathogens In Poultry Production And Processing To Defend Against Intentional Contamination, Silas B. Lankford 2017 University of Arkansas, Fayetteville

Simulating Foodborne Pathogens In Poultry Production And Processing To Defend Against Intentional Contamination, Silas B. Lankford

Computer Science and Computer Engineering Undergraduate Honors Theses

There is a lack of data in recent history of food terrorism attacks, and as such, it is difficult to predict its impact. The food supply industry is one of the most vulnerable industries for terrorist threats while the poultry industry is one of the largest food industries in the United States. A small food terrorism attack against just a single poultry processing center has the potential to affect a much larger population than its immediate consumers. In this work, the spread of foodborne pathogens is simulated in a poultry production and processing system to defend against intentional contamination. An ...


Software Development Waste, Todd Sedano, Paul Ralph, Cécile Péraire 2017 University of Auckland

Software Development Waste, Todd Sedano, Paul Ralph, Cécile Péraire

Cécile Péraire

Context: Since software development is a complex socio-technical activity that involves coordinating different disciplines and skill sets, it provides ample opportunities for waste to emerge. Waste is any activity that produces no value for the customer or user. Objective: The purpose of this paper is to identify and describe different types of waste in software development. Method: Following Constructivist Grounded Theory, we conducted a two-year five-month participant-observation study of eight software development projects at Pivotal, a software development consultancy. We also interviewed 33 software engineers, interaction designers, and product managers, and analyzed one year of retrospection topics. We iterated between ...


Lessons Learned From An Extended Participant Observation Grounded Theory Study, Todd Sedano, Paul Ralph, Cécile Péraire 2017 University of Auckland

Lessons Learned From An Extended Participant Observation Grounded Theory Study, Todd Sedano, Paul Ralph, Cécile Péraire

Cécile Péraire

Context: Conducting a Grounded Theory study is rigorous, demanding, and challenging. Misperceptions exist within the software engineering community. Objective: The purpose of this paper is to describe one extended participant observation Grounded Theory study for aiding new empirical researchers wanting to run similar research studies. Method: Following Constructivist Grounded Theory, we conducted a two-year five-month participant-observation of eight software development projects at Pivotal, a software development organization; interviewed 33 software engineers, interaction designers, and product managers; and analyzed one year of retrospection topics. We iterated between analysis and theoretical sampling until achieving theoretical saturation, publishing papers on team code ownership ...


On Intelligent Mitigation Of Process Starvation In Multilevel Feedback Queue Scheduling, Joseph E. Brown 2017 Kennesaw State University

On Intelligent Mitigation Of Process Starvation In Multilevel Feedback Queue Scheduling, Joseph E. Brown

Master of Science in Computer Science Theses

CPU time-share process schedulers for computer operating systems have existed since Corbato published his paper on the Compatible Time Sharing System in 1962 [8]. With this new type of scheduler came the need to effectively divide CPU time between N processes, where N could be 2 or more processes. Modern time-sharing process schedulers which have been developed in the decades since have been designed to favor shorter, interactive processes over long-running processes, especially when incoming demand for CPU time exceeds supply and process starvation is inevitable. These schedulers, including Linux CFS, FreeBSD Ule, and the Solaris Fair Share Scheduler, are ...


Corgi: Compute Oriented Recumbent Generation Infrastructure, Christopher Allen Hunt, Christopher Allen Hunt 2017 California Polytechnic State University, San Luis Obispo

Corgi: Compute Oriented Recumbent Generation Infrastructure, Christopher Allen Hunt, Christopher Allen Hunt

Master's Theses and Project Reports

Creating a bicycle with a rideable geometry is more complicated than it may appear, with today’s mainstay designs having evolved through years of iteration. This slow evolution coupled with the bicycle’s intricate mechanical system has lead most builders to base their new geometries off of previous work rather than expand into new design spaces. This crutch can lead to slow bicycle iteration rates, often causing bicycles to all look about the same. To combat this, several bicycle design models have been created over the years, with each attempting to define a bicycle’s handling characteristics given its physical ...


Numerical Modeling Of Tornado-Like Vortex And Its Interaction With Bluff- Bodies, Zoheb Nasir 2017 The University of Western Ontario

Numerical Modeling Of Tornado-Like Vortex And Its Interaction With Bluff- Bodies, Zoheb Nasir

Electronic Thesis and Dissertation Repository

The study the flow structure of tornado-like vortices and their impact over engineering structures is important due to the extent of tornado induced fatalities and damages observed each year in North America and around the world. In the present study, a numerical modeling approach inspired by the WindEEE Dome and the modified version of Ward’s Tornado Simulator has been developed. Using a full-scale numerical simulator, tornadoes of different intensities have been simulated for different swirl ratio values to study flow structures in comparison with previous studies. The effect of topographic features on the tornado-like vortex has been investigated for ...


A Hybrid Mpi-Openmp Strategy To Speedup The Compression Of Big Next-Generation Sequencing Datasets, Sandino Vargas-Perez, Fahad Saeed 2017 WMU

A Hybrid Mpi-Openmp Strategy To Speedup The Compression Of Big Next-Generation Sequencing Datasets, Sandino Vargas-Perez, Fahad Saeed

Parallel Computing and Data Science Lab Technical Reports

DNA sequencing has moved into the realm of Big Data due to the rapid development of high-throughput, low cost Next-Generation Sequencing (NGS) technologies. Sequential data compression solutions that once were sufficient to efficiently store and distribute this information are now falling behind. In this paper we introduce phyNGSC, a hybrid MPI-OpenMP strategy to speedup the compression of big NGS data by combining the features of both distributed and shared memory architectures. Our algorithm balances work-load among processes and threads, alleviates memory latency by exploiting locality, and accelerates I/O by reducing excessive read/write operations and inter-node message exchange. To ...


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