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An Interactive Design Environment For Coal Piping System , Gengxun Huang Jan 2006

An Interactive Design Environment For Coal Piping System , Gengxun Huang

Retrospective Theses and Dissertations

The design of coal piping system of a coal-fired power plant is a complex and time-consuming engineering task that involves meeting of several design objectives and constraints. The distribution of coal particles in a pneumatic pipeline can be highly inhomogeneous. Current coal piping design technology relies on empirical model and does not consider particle distribution characteristics in the pipe. In this thesis, a design tool which couples a validated detailed pipe model and an interactive optimization algorithm is developed. This new design tool uses evolutionary algorithms (EAs) as the optimization algorithm, and computational fluid dynamics (CFD) as the evaluation mechanism ...


Investigation Of The Performance Of Articular Cartilage And Synthetic Biomaterials In Multi-Directional Sliding Motion As In Orthopedic Implants , Christian John Schwartz Jan 2006

Investigation Of The Performance Of Articular Cartilage And Synthetic Biomaterials In Multi-Directional Sliding Motion As In Orthopedic Implants , Christian John Schwartz

Retrospective Theses and Dissertations

The performance of several synthetic biomaterials and bovine articular cartilage were investigated in terms of their suitability for use as articulating surfaces in artificial joints. The Dual-Axis Wear Simulator (DAWS), a wear testing machine that simulates conditions in a synovial joint, was designed and fabricated to enable investigators to measure the wear of such materials in multi-directional sliding while immersed in a bovine serum lubricant solution. This machine was used initially to determine the wear mechanisms and wear amounts of ultra-high molecular weight polyethylene (UHMWPE), polytetrafluoroethylene (PTFE), polyoxymethylene (POM), and the compliant elastomer Pellethane(TM) 2363-80A. It was found that ...


Computational Fluid Dynamic Modeling Of Acoustic Liquid Manipulation , Nicholus Ryan Clinkinbeard Jan 2006

Computational Fluid Dynamic Modeling Of Acoustic Liquid Manipulation , Nicholus Ryan Clinkinbeard

Retrospective Theses and Dissertations

Acoustic liquid manipulation, or ALM, is a term used to qualify three effects of nonlinear sound transmitted through fluid: radiation pressure, streaming, and heating. ALM is harnessed for a number of uses, such as the creation of fountains, formation of jets, and the destruction of cancerous tumors. As with any physical phenomenon, a computational model is desired to allow prediction of ALM.;Since prior work associated with this study produced a model for nonlinear sound, this thesis focused on developing computational fluid dynamic code to predict fluid velocity and heating. The model was compared with experimental data for water at ...


The Measurement Of Flame Propagation Within An Electrostatic Particulate System , Ryan Mark Kroll Jan 2006

The Measurement Of Flame Propagation Within An Electrostatic Particulate System , Ryan Mark Kroll

Retrospective Theses and Dissertations

A variant of the Electrostatic Particulate Chamber was developed to directly measure flame propagation velocity of combustible gas and powder mixtures. Flame propagation velocity was measured by tracking the position of the flame front utilizing the ionization effect and current due to a high intensity applied electric field. The position of the front was determined with respect to time by monitoring the voltage spike and current flow through spatially separated resistors.;With this technique, the flame propagation velocity was initially tested in gas mixtures of propane/air and natural gas/air. Measured velocities were compared to published values for burning ...


The Nature Of The Distinctive Microscopic Features In R5(Si[Subscript X]Ge[Subscript 1-X])4 Magnetic Refrigeration Materials , Ozan Ugurlu Jan 2006

The Nature Of The Distinctive Microscopic Features In R5(Si[Subscript X]Ge[Subscript 1-X])4 Magnetic Refrigeration Materials , Ozan Ugurlu

Retrospective Theses and Dissertations

Magnetic refrigeration is a promising technology that offers a potential for high energy efficiency. The giant magnetocaloric effect of the R5(Six,Ge1-x)4 alloys (where R=rare-earth and 0≤x≤1), which was discovered in 1997, make them perfect candidates for magnetic refrigeration applications. In this study the microstructures of Gd5(SixGe1-x)4 alloys have been characterized using electron microscopy techniques, with the focus being on distinctive linear features first examined in 1999. These linear features have been observed in R5(Six,Ge1-x) 4 alloys prepared from different rare-earths (Gd, Tb, Dy and Er) with different crystal structures (Gd5Si4-type ...


Interactive Design Methods In Virtual Reality With Haptics , Andrew George Fischer Jan 2006

Interactive Design Methods In Virtual Reality With Haptics , Andrew George Fischer

Retrospective Theses and Dissertations

This research demonstrated the use of virtual reality and related interaction technology, such as haptics, in an immersive virtual design application. The goal was to present an effective methodology for interactive design where engineers alter products and investigate updated analysis results in real-time using a virtual environment. Research was presented as a series of four papers;Chapter 2 covered a history of the interactive design methodology and it's applications followed by the largest hurdles to effective interaction. Solutions where presented and their effectiveness demonstrated;The third chapter examined some limitations of the custom mesh-free analysis method used on the ...


Development Of An Adaptive Fuzzy Logic Controller For Hvac System , Rahul Laxman Navale Jan 2006

Development Of An Adaptive Fuzzy Logic Controller For Hvac System , Rahul Laxman Navale

Retrospective Theses and Dissertations

An adaptive approach to control a cooling coil chilled water valve operation, called adaptive fuzzy logic control (AFLC), is developed and validated in this study. The AFLC calculates the error between the supply air temperature and supply air temperature set point for air in an air handling unit (AHU) of a heating, ventilating, and air conditioning (HVAC) system and determines optimal fuzzy rule matrix to minimize the hydronic energy consumption while maintaining occupant comfort. The AFLC uses genetic algorithms and evolutionary strategies to determine the fuzzy rule matrix and fuzzy membership functions for an AHU in HVAC systems;Cooling coil ...


Fatigue Life Investigation For Cams With Translating Roller-Follower And Translating Flat-Face Follower Systems , Mwafak Mohammed Shakoor Jan 2006

Fatigue Life Investigation For Cams With Translating Roller-Follower And Translating Flat-Face Follower Systems , Mwafak Mohammed Shakoor

Retrospective Theses and Dissertations

The cam fatigue life of the translating roller---follower and translating flat---faced follower system has been investigated for polynomial and cycloidal displacement functions. Ioannides and Harris (IH) life prediction model are used to estimate the cam fatigue life. Computer program codes are written to calculate and simulate the different types of loads that act on the cam, the contact stresses in the cam and the followers and the 'volume under risk'. Ioannides---Harris theory is applied to the 'volume under risk' and expected fatigue life is calculated. The effects of cam base circle radius, cam angular velocity, roller---follower radius of curvature, cam ...


In-Process Tool Condition Monitoring Systems In Cnc Turning Operations , Soo-Yen Lee Jan 2006

In-Process Tool Condition Monitoring Systems In Cnc Turning Operations , Soo-Yen Lee

Retrospective Theses and Dissertations

The present study shows the development of in-process tool condition monitoring systems utilizing signal decomposition technique, statistical data analysis, and artificial neural networks system. Two systems; (1) the system based on the multiple regression, (2) the system based on artificial neural networks with back-propagation learning algorithms were developed;The raw signals obtained from two sensors (tri-axial accelerometer and AE sensor) with different machining parameters and tool conditions were examined and decomposed into six components by utilizing a wavelet transformation. The most significant components of each signal were found by statistical method and implemented to develop two in-process tool monitoring systems ...


The Numerical Simulation Of Turbulent Boundary Layers And Film Cooling , Kunlun Liu Jan 2006

The Numerical Simulation Of Turbulent Boundary Layers And Film Cooling , Kunlun Liu

Retrospective Theses and Dissertations

A new finite volume algorithm has been developed to solve a variety of flows by using large eddy simulation and direct numerical simulation. This finite volume algorithm was developed using a dual time stepping approach with a preconditioning technique and a new factorization implementation. The method takes the advantage of pressure based and density-based methods. Thus, it provides an efficient way to numerically solve the Navier-Stokes equations at the low Mach numbers. Meanwhile, to generate the inflow conditions for the simulation of turbulent boundary layers, a dynamic recycling method was proposed. In addition, a characteristic boundary condition method was suggested ...


Empirical Validations Of The Daylighting/Window Shading/Solar Gains Models In Building Energy Simulation Programs , Peter Gregory Loutzenhiser Jan 2006

Empirical Validations Of The Daylighting/Window Shading/Solar Gains Models In Building Energy Simulation Programs , Peter Gregory Loutzenhiser

Retrospective Theses and Dissertations

The purpose of this research was to evaluate the accuracies of building energy simulation programs when modeling glazing units and windows with and without shading devices and daylighting. Program outputs were compared with data from experiments performed at two research facilities designed for these types of studies;Six experiments were performed in a test cell located on the Swiss Federal Laboratories for Material Testing and Research (EMPA) campus in Duebendorf, Switzerland. After determining thermophysical properties, the thermal bridges of the test cell were analyzed using three dimensional heat transfer simulations. The experimental series started with a steady-state and a transient ...


Experimental Observations Of Shear Band Nucleation And Propagation In A Bulk Metallic Glass Using Wedge-Like Cylindrical Indentation , Antonia Maki Antoniou Jan 2006

Experimental Observations Of Shear Band Nucleation And Propagation In A Bulk Metallic Glass Using Wedge-Like Cylindrical Indentation , Antonia Maki Antoniou

Retrospective Theses and Dissertations

Bulk metallic glasses (BMGs), or amorphous metal alloys, have a unique combination of properties such as high strength, large elastic strain limit (up to 2%), corrosion resistance and formability. These unique properties make them candidates for precision mechanical elements, hinge supports, contact surfaces as well as miniaturized systems (MEMS). However, their limited ductility hinders further realizations of their industrial potential. Under uniaxial tension tests, metallic glass fails in a brittle manner with unstable propagation of a single shear band. There is a need to understand the conditions for shear band nucleation and propagation in order to achieve a superior material ...


Large Eddy Simulation Of Turbulent Pipe/Annular Supercritical Co2 Flow With Heat Transfer And Perfect Gas Flow In A Ribbed Annuli Passage , Xiaohang Wang Jan 2006

Large Eddy Simulation Of Turbulent Pipe/Annular Supercritical Co2 Flow With Heat Transfer And Perfect Gas Flow In A Ribbed Annuli Passage , Xiaohang Wang

Retrospective Theses and Dissertations

The present study is aimed at applying a recently developed generalized equation of state algorithm along with the system of equations for a time dependent outflow boundary that not only allows more general fluids to be computed, but also uses theoretical results on well-posedness of Navier-Stokes boundary conditions to construct a systematic method for specifying these boundary conditions. An exact "discretely" non-reflecting boundary condition is derived for the three-dimensional filtered compressible Navier-Stokes equations based on Cartesian coordinates which are discretized with finite volume schemes. The test results and comparisons with other methods were conducted to explore its precision and robustness ...


Experimental Study Of Turbulent Mixing In A Rectangular Reactor , Hua Feng Jan 2006

Experimental Study Of Turbulent Mixing In A Rectangular Reactor , Hua Feng

Retrospective Theses and Dissertations

Turbulent mixing in confined shear flows, including a rectangular jet and a rectangular wake, was investigated using both non-simultaneous particle image velocimetry (PIV) and planar laser-induced fluorescence (PLIF) and simultaneous PIV and PLIF techniques. Based on the hydraulic diameter and the bulk velocity, the Reynolds number was 50,000 for the jet, and was 37,500 for the wake flow. The Schimdt number of the fluorescence dye is 1,250;The experimental data were analyzed for flow statistics such as mean velocity, Reynolds stresses; turbulent kinetic energy, turbulent dissipation, concentration mean and variance, turbulent fluxes, turbulent viscosity and diffusivity, and ...


Adaptive Resonant Mode Control For High Frequency Tonal Noise , Tom Waite Jan 2006

Adaptive Resonant Mode Control For High Frequency Tonal Noise , Tom Waite

Retrospective Theses and Dissertations

The main contribution of this thesis is the formulation of a new type of resonant mode controller for which a closed form expression is derived. This controller requires no design iterations and the gain margin can be specified ahead of time (phase margin is always infinite). This controller differs from standard resonant control in that it acts directly on a disturbance rather than damping resonant poles of the system plant. This allows for a notch to be created in the disturbance anywhere in the spectrum, not just at resonant modes of the system. The experimental setup involves headrest and headset ...


Case Study Of A High Efficiency Home , David Aaron Hamilton Jan 2006

Case Study Of A High Efficiency Home , David Aaron Hamilton

Retrospective Theses and Dissertations

The PowerHouse home in Newton, IA was designed and built with energy efficiency in mind. The main technology being studied is ZeroNet's "super envelope" design, which incorporates expanded polystyrene bonded with a fiber-reinforced concrete coating on each side. The highly insulated walls and roof of the PowerHouse should reduce heating and cooling energy consumption by up to 50% throughout the year while the sophisticated HVAC equipment will improve air quality and human comfort by reducing pollutants inside the residence.;Research Goals. (1) Evaluate building envelope performance with regards to design heating and cooling loads; (2) Estimate the annual performance ...


Empirical Validation Of Building Energy Simulation Software:: Energyplus , Som Sagar Shrestha Jan 2006

Empirical Validation Of Building Energy Simulation Software:: Energyplus , Som Sagar Shrestha

Retrospective Theses and Dissertations

A study was conducted to compare the simulation results from EnergyPlus building energy simulation software to actual building energy usage. The building used in the study was the Energy Resource Station located in Ankeny, Iowa. The building consists of controlled test rooms, dedicated air handling units and dedicated air-cooled chillers for the purpose of obtaining quality data for empirical validation studies. Weather data was also collected at the facility and used in the simulation software. Three tests were conducted to provide variation in cooling coil operating conditions and chiller loading. For one test an electric humidifier was used to provide ...


The Development Of A Virtual Reality Based Cad System For Design Review , Thomas Anthony Erlemeier Jan 2006

The Development Of A Virtual Reality Based Cad System For Design Review , Thomas Anthony Erlemeier

Retrospective Theses and Dissertations

Virtual reality is currently utilized to view and evaluate product designs but is not used to alter designs. The design is typically completed on desktop workstations with CAD software and then evaluated within a virtual environment. Integrating VR and CAD could potentially improve designs by allowing several engineers and managers to critique and modify designs together, enabling concurrent engineering.;This thesis discusses the development of a virtual reality based CAD system for altering designs during a design review. A list of criteria was first created to assess the system's effectiveness in a design review which formed the basis for ...


Using X-Ray Computed Tomography To Measure Local Gas Holdup In A Stirred Tank Reactor , Jason J. Ford Jan 2006

Using X-Ray Computed Tomography To Measure Local Gas Holdup In A Stirred Tank Reactor , Jason J. Ford

Retrospective Theses and Dissertations

Gas holdup is one of the most important hydrodynamic parameters needed for reliable design, performance estimation, and scale-up of stirred tank reactors (STRs). In the present work, local gas holdup is measured in an acrylic stirred tank reactor equipped with a Rushton impeller using X-ray computed tomography (CT) for many different operating conditions. Power consumption for different operating conditions is determined to identify various STR flow regimes. The gas holdup results obtained by X-ray CT imaging are presented as: (i) profiles along all 3 axes, (ii) plots of local gas holdup along the x-axis, (iii) average gas holdup for z-slice ...