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Energy Efficiency Enhancements To A Low Energy High Performance Building, Joel Clifton Logan Jan 2008

Energy Efficiency Enhancements To A Low Energy High Performance Building, Joel Clifton Logan

Retrospective Theses and Dissertations

This report discusses energy efficiency enhancements made to a low energy, high performance office building. The building studied is the Iowa Association of Municipal Utilities headquarters located in Ankeny, Iowa, just north of Des Moines. Monitoring the energy use of the building for over six years has revealed that it has an average annual site energy use of 29,300 Btu/ft2. This is 68% less energy than that used by the average U.S. office building and 74% less energy than the average office building in climate zone 2, the location of Ankeny.;Three areas of energy use were ...


Establishing An Advanced Engineering Framework For Engineering Decision Making, Douglas Stinson Mccorkle Jan 2008

Establishing An Advanced Engineering Framework For Engineering Decision Making, Douglas Stinson Mccorkle

Retrospective Theses and Dissertations

No abstract provided.


The Evaluation Of Maize Genotypes For Potential Use In Cellulosic Ethanol Production, Krystal Marie Kirkpatrick Jan 2008

The Evaluation Of Maize Genotypes For Potential Use In Cellulosic Ethanol Production, Krystal Marie Kirkpatrick

Retrospective Theses and Dissertations

Corn stover represents a potential lignocellulosic feedstock that may benefit the emerging cellulosic ethanol industry. This study was conducted to determine dry matter yield and quality characteristics of maize stover, cob, and husk plant fractions, and to make predictions of potential ethanol yields. Detergent fiber predictions were made for each plant fraction using near infrared reflectance spectroscopy (NIRS). Predicted values were used to determine ethanol potential using a modified version of the National Renewable Energy Lab (NREL) theoretical ethanol yield calculator. Although significant, not as much variation was present among genotypes and plant fractions for chemical composition as for dry ...


Energy Comparison Of Under Floor Air Distribution Heating Ventilation And Air Conditioning Systems In Office Buildings, Jonathon Richard Giles Jan 2008

Energy Comparison Of Under Floor Air Distribution Heating Ventilation And Air Conditioning Systems In Office Buildings, Jonathon Richard Giles

Retrospective Theses and Dissertations

The purpose of this paper is to compare energy consumption with under floor air distribution systems for office buildings, specifically a call center application.;The building being modeled will have an HVAC system that utilizes an underfloor air distribution system (UFAD). This type of system allows air to be introduced into the plenum space under the floor. The air comes up through the floor into the space through plenum space pressurization. The air is then taken out of the space up high and returned back to the air handling unit.;The three systems reviewed for delivery of the air to ...


Manufacturability Analysis For Non-Feature-Based Objects, Ye Li Jan 2008

Manufacturability Analysis For Non-Feature-Based Objects, Ye Li

Retrospective Theses and Dissertations

This dissertation presents a general methodology for evaluating key manufacturability indicators using an approach that does not require feature recognition, or feature-based design input. The contributions involve methods for computing three manufacturability indicators that can be applied in a hierarchical manner. The analysis begins with the computation of visibility, which determines the potential manufacturability of a part using material removal processes such as CNC machining. This manufacturability indicator is purely based on accessibility, without considering the actual machine setup and tooling. Then, the analysis becomes more specific by analyzing the complexity in setup planning for the part; i.e. how ...


Modeling And Direct Numerical Simulation Of Particle-Laden Turbulent Flows, Ying Xu Jan 2008

Modeling And Direct Numerical Simulation Of Particle-Laden Turbulent Flows, Ying Xu

Retrospective Theses and Dissertations

The objective of this study is to improve Eulerian-Eulerian models of particle-laden turbulent flow, especially the interphase TKE transfer term and the dissipation rate in Eulerian-Eulerian models. We begin by understanding the behavior of two existing models---one proposed by Simonin (1996b), and the other by Ahmadi (1989)---in the limiting case of statistically homogeneous particle-laden turbulent flow. The decay of particle-phase and fluid-phase turbulent kinetic energy (TKE) is compared with point-particle direct numerical simulation data. Even this simple flow poses a significant challenge to current models, which have difficulty in reproducing important physical phenomena such as the variation of turbulent ...


An Energy And Cost Analysis Of Residential Ground-Source Heat Pumps In Iowa, Matthew James Swenka Jan 2008

An Energy And Cost Analysis Of Residential Ground-Source Heat Pumps In Iowa, Matthew James Swenka

Retrospective Theses and Dissertations

The objective of this study was to evaluate residential ground-source heat pumps throughout the state of Iowa and use that information to develop educational opportunities for prospective ground-source heat pump owners. The ground-source heat pumps were evaluated based on performance, efficiency, and economics. The study was limited to similar homes throughout the state of Iowa, recent constructions (1997 to 2001), and vertically or horizontally configured loops.;Energy audits were conducted for each home to obtain building characteristics. Using the characteristics, heating and cooling loads were estimated for each home. Utilizing the heating and cooling loads along with utility bill and ...


Light-Trapping Enhancement In Thin Film Solar Cells With Photonic Crystals, Dayu Zhou Jan 2008

Light-Trapping Enhancement In Thin Film Solar Cells With Photonic Crystals, Dayu Zhou

Retrospective Theses and Dissertations

Photovoltaics (or solar cell) has been an active area for research and development, driven by the world's constantly increasing needs for power. Among the current solar technologies, thin film solar cell promises lower cost, but at the expense of lower power conversion efficiency. The efficiency of thin film solar cell can be improved using light confinement schemes commonly referred to as light-trapping. In this thesis, we develop novel light-trapping schemes utilizing photonic crystals (PCs). The optical modeling is performed with a rigorous scattering matrix approach, where Maxwell's equations are solved in Fourier space, and simulations are carried out ...


Characterization Of Conductive Surface Printing Via Electric Field Induced Ion Transport, Khiam-How Low Jan 2008

Characterization Of Conductive Surface Printing Via Electric Field Induced Ion Transport, Khiam-How Low

Retrospective Theses and Dissertations

A novel methodology to imprint micron size features on copper surface has been adopted in this study. The process of printing is based on focused electric field induced ion transport across a cation selective NafionRTM membrane. The imprinting technology itself is environmentally benign because electrolyte consists of Sulfuric Acid (H2SO4) and Cupric Sulfate (CuSO4) are encapsulated by NafionRTM membrane in a copper made cathode chamber and it is sealed and recycled. In addition, the imprinted surface does not come in contact with corrosive chemicals which minimize the post cleaning process.;Three different methods of printing were embraced here in this ...


Force Interaction Characterization Between Thrombin And Dna Aptamers, Janice Dionne Marquardt Jan 2008

Force Interaction Characterization Between Thrombin And Dna Aptamers, Janice Dionne Marquardt

Retrospective Theses and Dissertations

The first purpose of this study is to examine using AFM height measurements to detect changes in nucleic acid and protein interactions. This study used a thiolated adenine oligonucleotide (Poly A) and thymine DNA strand (Poly T) or 2 kDa poly(ethylene) glycol (PEG) as control, and the thrombin aptamer and thrombin for detection pair. The poly A and aptamer were printed using microcontact printing, then exposed to complementary species. There was a height change after binding to the target species, so it is feasible for height data to detect binding. The second purpose of this study is to use ...


The Role Of Information Flow In Engineering Optimization, Steven Michael Corns Jan 2008

The Role Of Information Flow In Engineering Optimization, Steven Michael Corns

Retrospective Theses and Dissertations

Current optimization techniques work well for single components represented by a single model. However, many of the problems we face today are multi-disciplinary problems requiring the integration of complex models from different fields to gain a more complete understanding of the overall performance of a biological, engineering, or human system. One example is a modern automobile. Multiple systems (such as the power train and electronic engine control system) are designed and built from various assemblies and components, all of which are then integrated into one final product. This design process evokes a systems-of-systems concept that is also found in agricultural ...


A Framework For Tumor Segmentation And Interactive Immersive Visualization Of Medical Image Data For Surgical Planning, Jung Leng Foo Jan 2008

A Framework For Tumor Segmentation And Interactive Immersive Visualization Of Medical Image Data For Surgical Planning, Jung Leng Foo

Retrospective Theses and Dissertations

This dissertation presents the framework for analyzing and visualizing digital medical images. Two new segmentation methods have been developed: a probability based segmentation algorithm, and a segmentation algorithm that uses a fuzzy rule based system to generate "similarity" values for segmentation. A visualization software application has also been developed to effectively view and manipulate digital medical images on a desktop computer as well as in an immersive environment.;For the probabilistic segmentation algorithm, image data are first enhanced by manually setting the appropriate window center and width, and if needed a sharpening or noise removal filter is applied. To initialize ...


Mechanics Of Wire Saw Machining Process: Experimental Analyses And Modeling, Egemen Teomete Jan 2008

Mechanics Of Wire Saw Machining Process: Experimental Analyses And Modeling, Egemen Teomete

Retrospective Theses and Dissertations

Wire saw process is widely used to slice many ceramic crystals that are utilized in a wide range of engineering applications ranging from silicon wafers in microelectronics and photovoltaic industries to piezo-crystals for actuators and sonar detectors. The process has a higher yield, lower kerf loss and lower surface damage with respect to inner diameter saw. The wire saw process allows higher diameter and thinner wafer cutting. The process is also used in cutting almost all brittle materials including; ultra-hard carbides, high density or foam ceramics, glasses, sapphire and rocks. Wire saw process represents 30% of the total silicon wafer ...


Development Of A Multiblock Solver Utilizing The Lattice Boltzmann And Traditional Finite Difference Methods For Fluid Flow Problems, Aditya C. Velivelli Jan 2008

Development Of A Multiblock Solver Utilizing The Lattice Boltzmann And Traditional Finite Difference Methods For Fluid Flow Problems, Aditya C. Velivelli

Retrospective Theses and Dissertations

This dissertation develops the lattice Boltzmann method (LBM) as a strong alternative to traditional numerical methods for solving incompressible fluid flow problems. The LBM outperforms traditional methods on a standalone basis for certain problem cases while for other cases it can be coupled with the traditional methods using domain decomposition. This brings about a composite numerical scheme which associates the efficient numerical attributes of each individual method in the composite scheme with a particular region in the flow domain. Coupled lattice Boltzmann-traditional finite difference procedures are developed and evaluated for CPU time reduction and accuracy of standard test cases. The ...


Experimental And Simulation Study Of Demand Controlled Ventilation, Li Zhang Jan 2008

Experimental And Simulation Study Of Demand Controlled Ventilation, Li Zhang

Retrospective Theses and Dissertations

The purpose of this study is to compare energy use and CO 2 concentration for a multizone building utilizing three ventilation control strategies. The three strategies are occupancy-based demand controlled ventilation (DCV), carbon-dioxide based DCV and constant ventilation. The study compares the building's energy consumption using the three methods for summer, winter and transition seasons. To perform the study, an indoor air quality (IAQ) model was developed and used in conjunction with EnergyPlus to simulate the building. Experiments were conducted at the Iowa Energy Center's Energy Resource Station to validate the IAQ model. Results from the study show ...


Investigation Into The Stress Assisted Damage Of Copper Surface Under Single Asperity: Influence Of Contact Pressures, Surfaces Stress States And Environments, Bun Hiong Chua Jan 2008

Investigation Into The Stress Assisted Damage Of Copper Surface Under Single Asperity: Influence Of Contact Pressures, Surfaces Stress States And Environments, Bun Hiong Chua

Retrospective Theses and Dissertations

An experiment setup was used to investigate the effects of contact loads, surface stress state and surface environment on dissolution and damage of copper surface. A range of surface stress state was generated with a four-point-bending setup on a well-polished copper sample. Single asperity contact was investigated using the cantilever tip of an Atomic Force Microscope. Controlled tip contact pressures were applied on the copper surface to mechanically stimulate the stressed surface. The experiment was performed in different environments to determine the chemical effects. Volume of material removed during the process was measured to determine material removal rate as a ...


Simulating Energy Efficiency In Laboratory Buildings, Robert Marcel Milbrandt Jan 2008

Simulating Energy Efficiency In Laboratory Buildings, Robert Marcel Milbrandt

Retrospective Theses and Dissertations

Today's laboratory buildings are large consumers of energy. The ventilation requirements of these buildings mandate that large quantities of outside air be brought into the building. The advent of air-to-air heat recovery systems has been proven to significantly decrease the energy input needed to condition outside air. This project is a detailed energy simulation of a laboratory building on the campus of Iowa State University in Ames, Iowa. Using Trane TRACE 700 software, a detailed model of the building was created, and energy efficient measures were simulated. These simulations include the proper control of outside air flow rates, the ...


A Static Analysis Of Maximum Wind Penetration In Iowa And A Dynamic Assessment Of Frequency Response In Wind Turbine Types, Eknath Vittal Jan 2008

A Static Analysis Of Maximum Wind Penetration In Iowa And A Dynamic Assessment Of Frequency Response In Wind Turbine Types, Eknath Vittal

Retrospective Theses and Dissertations

As the energy industry moves into the 21st century the use and research into renewable resources has expanded significantly. Whether it is wind, biomass, or solar, the industry is seeking ways to breakthrough and integrate the newest technologies into their power systems. Wind energy, in particular, has seen significant expansion since the 1980's, with generating capability of wind turbines increasing dramatically from 50 kW to nearly 5 MW presently. Seeking to introduce larger levels of wind generation in the Iowa electricity system, the goal of this thesis was to: First, determine the maximum wind penetration level of the existing ...


Modeling And Simulation Of Nanoparticle Aggregation In Colloidal Systems, Sergiy Markutsya Jan 2008

Modeling And Simulation Of Nanoparticle Aggregation In Colloidal Systems, Sergiy Markutsya

Retrospective Theses and Dissertations

Prediction of colloidal nanoparticle aggregation is an important problem which needs to be solved in an accurate and efficient manner. Thus, accurate modeling of physico-chemical interactions is required. In addition, to have good aggregation statistics, large system sizes should be considered, which can significantly increase computational cost and decrease code efficiency. In ideal case model which is chosen to predict colloidal nanoparticle aggregation should accurately describe physico-chemical interactions of relatively large physical systems, and at the same time, simulate at low computational cost.;In this research, two simulation approaches, molecular dynamics (MD) and Brownian dynamics (BD), are analyzed and compared ...


Carbon Conversion During Bubbling Fluidized Bed Gasification Of Biomass, Kevin Jay Timmer Jan 2008

Carbon Conversion During Bubbling Fluidized Bed Gasification Of Biomass, Kevin Jay Timmer

Retrospective Theses and Dissertations

Gasification is one means of transforming biomass so that it can be more easily utilized as a renewable source of thermal energy, transportation fuel, and chemicals. Under typical gasification conditions it is not uncommon that a portion of the carbon entering with the biomass leaves the reactor unconverted as char. Understanding and improving carbon conversion during biomass gasification in an atmospheric bubbling fluidized bed reactor is the focus of this study.;To better understand the intricacies of biomass gasification a carbon conversion analytic methodology was developed. The methodology is based on a mass balance of the fixed carbon entering and ...


Predicting Loads On Ground Engaging Tillage Tools Using Computational Fluid Dynamics, Mark Eugene Barker Jan 2008

Predicting Loads On Ground Engaging Tillage Tools Using Computational Fluid Dynamics, Mark Eugene Barker

Retrospective Theses and Dissertations

A new method of evaluating tillage tools using computational fluid dynamics is proposed. Steady-state CFD only and transient two-way fluid-structure interaction simulations were run to predict draft and vertical forces on a spring-reset field cultivator standard. Using CFD the soil was treated as a visco-plastic fluid using the Bingham-plastic material model. Lab tests were run using a rigid flat steel bar and a production field cultivator standard with 178 and 254 mm sweeps for comparison. The results indicate that the method can be used to reasonably predict the draft force to within three standard deviations of the average measured draft ...


Nondestructive Detection And Characterization Of Damages In Honeycomb Composite Structures, Cory Foreman Jan 2008

Nondestructive Detection And Characterization Of Damages In Honeycomb Composite Structures, Cory Foreman

Retrospective Theses and Dissertations

This thesis discusses many existing methods of nondestructive evaluation used on honeycomb structures ranging from ultrasonic transduction to various low frequency techniques. The focus, however, is given to a newly developed technique based on hysteresis effects in force-displacement curves. The area enclosed by the hysteresis loop represents the amount of energy absorbed by the sample during the loading and unloading phases. It is believed that the cause of the energy absorption is due to increased internal frictional loses which occur when the sample is damaged. The loop area was found to correlate well with the level of damage sustained by ...


Analysis Of A Ddgs Air-Drying System With Heat Recovery, Christopher Brady Hoeck Jan 2008

Analysis Of A Ddgs Air-Drying System With Heat Recovery, Christopher Brady Hoeck

Retrospective Theses and Dissertations

Dry Distiller Grains with Soluble (DDGS) are a co-product of the conversion from corn into Ethanol fuel. Several applications depend on the ability of a drying process to remove moisture from a product, such as DDGS, in an effective and economical manner. Common drying methods use air to facilitate product drying as it proficiently absorbs the unwanted moisture, creating a moist-air mixture that captures both the latent and sensible heat released from the product. The most economical approach to an Air Drying System integrates a heat recovery system that transfers the heat removed by the moist-air mixture during drying back ...


Decision Making Limitations From Communication Barriers In Government Structures In Chinese Rural Energy Projects, Nathan Gregory Johnson Jan 2008

Decision Making Limitations From Communication Barriers In Government Structures In Chinese Rural Energy Projects, Nathan Gregory Johnson

Retrospective Theses and Dissertations

Field research was conducted in the Li Cheng District (about 1,200 km 2) of Shan Dong Province. Data collection occurred during a two-week period in July 2006. At that time, seven villages represented all relevant sites in the district that contained gasification technologies. Small-group interviews with village leaders, station managers, and community members were conducted locally. Contact with external government agencies and technology scientists completed the set of potential stakeholders.;This study analyzes the failure of state-owned energy development initiatives in China. Communication barriers in bureaucratic structures and culturally prescribed patterns of interaction were revealed as inhibiting information transfer ...


Devising A More Robust Automated Detection Method Using Audio Frequency Spectra, Gregory Stargell Jan 2008

Devising A More Robust Automated Detection Method Using Audio Frequency Spectra, Gregory Stargell

Retrospective Theses and Dissertations

The space shuttle, Columbia had a suitcase piece of the SOFI strike the wing of the shuttle causing its demise. Detection methods were evaluated to detect defects in the foam. One of the methods being free field acoustics was explored. Previous works were done in this area, and it showed promise as it was able to detect defects. However all defects or the defects that had significance to the eye was not detected. The method developed before is looked into and was improved upon addressing the problems. Developing a baseline curve and region to compare the data would be two ...


Visualizing Fluidized Beds With X-Rays, Nathan Paul Franka Jan 2008

Visualizing Fluidized Beds With X-Rays, Nathan Paul Franka

Retrospective Theses and Dissertations

This study applies minimum fluidization velocity experiments, X-ray computed tomography (CT), X-ray stereography, and particle tracking to fluidized beds of glass beads, ground walnut shell, and ground corncob operating with a variety of flow conditions. 3-D local, time-averaged gas holdup is calculated from CT data, while dynamic features are captured by X-ray stereography. The results show that CT is most effective on glass bead fluidized beds. Due to high X-ray attenuation, glass bead CT data has higher resolution than walnut shell and corncob beds. Glass bead gas holdup data also feature the lowest noise due to the high homogeneity of ...


Techno-Economic Evaluations Of Biofuel Technologies, Mark Mba Wright Jan 2008

Techno-Economic Evaluations Of Biofuel Technologies, Mark Mba Wright

Retrospective Theses and Dissertations

This thesis consists of three related techno-economic studies of biofuels production. The major purpose of these studies is to establish meaningful comparisons between different technologies for producing biofuels and explore scenarios leading to optimal biofuel costs.;Three journal papers have been published in Biofuels, Bioprocessing, and Biorefining from the results of this study: "Comparative economics of biorefineries based on the biochemical and thermochemical platforms", "Establishing the optimal size of different kinds of biorefineries", and "Distributed processing of biomass to bio-oil for subsequent production of Fischer-Tropsch liquids".;Several major conclusions were drawn from this study. Advanced biorefineries will require capital investments ...


Characterization Of Actuator Behaviors Of Ferrogels Obtained From Physical And Chemical Cross-Linking Methods, Geunhyung Park Jan 2008

Characterization Of Actuator Behaviors Of Ferrogels Obtained From Physical And Chemical Cross-Linking Methods, Geunhyung Park

Retrospective Theses and Dissertations

Ferrogels are soft polymer materials containing a filler of magnetic particles that allow the material to be activated by magnetic fields. These materials have shown capabilities for large strains, fast response, ease of synthesis and biocompatibility and have potential applications including artificial muscles, controlled drug release systems, and hyperthermia cancer treatment. In this work, the actuator behavior for a selection of ferrogel compositions and synthesis methods are characterized including their free strain and loading behavior. Samples were synthesized using either chemical or physical methods using Sodium Tetra-borate (Na2B4O7 ยท 10(H2O)) or freeze-thaw cycle, respectively. Compositions consisting of PVA of 4 ...


Improving Solution Characteristics Of Particle Swarm Optimization Through The Use Of Digital Pheromones, Parallelization, And Graphical Processing Units (Gpus), Vijay Kiran Kalivarapu Jan 2008

Improving Solution Characteristics Of Particle Swarm Optimization Through The Use Of Digital Pheromones, Parallelization, And Graphical Processing Units (Gpus), Vijay Kiran Kalivarapu

Retrospective Theses and Dissertations

Deterministic optimization methods such as steepest descent, conjugate gradient and Newton's methods are known for their robustness in iteratively reducing the objective function value for minimization problems. However, they are primarily suitable for solving single objective function problems that are unimodal and continuous. With increased sophistication in engineering problems, multimodal and multi-objective problems have become more prevalent drastically reducing the effectiveness of deterministic methods. This led to the development of heuristic methods, particularly evolutionary methods such as Genetic Algorithms, Ant Colony Optimization, and Particle Swarm Optimization. These methods have multiple design points exploring the design space over iterations as ...


Friction And Wear Behavior Of Ultra-High Molecular Weight Polyethylene As A Function Of Crystallinity And In The Presence Of The Phospholipid Dppc (Dipalmitoyl Phosphatidylcholine), Angela Lynette Bruck Jan 2007

Friction And Wear Behavior Of Ultra-High Molecular Weight Polyethylene As A Function Of Crystallinity And In The Presence Of The Phospholipid Dppc (Dipalmitoyl Phosphatidylcholine), Angela Lynette Bruck

Retrospective Theses and Dissertations

No abstract provided.