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Evaluation Of In-Situ Stiffness Of Subgrade By Resilient And Fwd Modulus, Daehyeon Kim, Yigong Ji, Nayyar Zia Siddiki 2010 Indiana Department of Transportation

Evaluation Of In-Situ Stiffness Of Subgrade By Resilient And Fwd Modulus, Daehyeon Kim, Yigong Ji, Nayyar Zia Siddiki

JTRP Technical Reports

Resilient modulus has been used for characterizing the stress-strain behavior of subgrade soils subjected to traffic loadings in the design of pavements. With the recent release of the M-E Pavement Design Guide, highway agencies are further encouraged to implement the resilient modulus test to improve subgrade design. A laboratory resilient modus test and a FWD test are usually used to obtain the resilient modulus of subgrade. However, the difference in the resilient modulus obtained from these two methods is considerably large due to the fact that these tests are conducted under different conditions. This difference gives engineers a significant confusion ...


An Experimental Investigation On Viscoelastic Behavior In Tunable, Hao-Han Hsu, Dimitrios Peroulis 2010 Purdue University - Main Campus

An Experimental Investigation On Viscoelastic Behavior In Tunable, Hao-Han Hsu, Dimitrios Peroulis

PRISM: NNSA Center for Prediction of Reliability, Integrity and Survivability of Microsystems

Abstract—In this paper, the viscoelastic behavior of a tunable RF-MEMS resonator and its impacts are studied by means of direct RF measurements for the first time. This tunable resonator consists of one λ/2 coplanar waveguide (CPW) resonator and two nanocrystalline-Ni RF-MEMS varactors. S-parameters of this tunable resonator have been measured for 80 hours under a bi-state bias condition of 0 and 40 V. It is demonstrated that the resonant frequency is shifted by 90 MHz and the varactor deformed by 0.12 μm over the 80 hour period. The gap of the loaded varactor is extracted from the ...


Phytoremediation Of Energetic Compounds At Eglin Air Force Base, Travis Jake Anderson 2010 University of Iowa

Phytoremediation Of Energetic Compounds At Eglin Air Force Base, Travis Jake Anderson

Theses and Dissertations

The energetic compounds TNT (2,4,6-trinitrotoluene), RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine), and HMX (octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine) contaminate military testing ranges worldwide yet are known to be degraded by plants and microbes in the laboratory. However, these contaminants remain persistent in the environment and represent a health threat to both humans and ecosystems. The use of traditional soil remediation technologies, such as landfilling or incineration, require large excavation costs and disrupt the ecology of the site. Phytoremediation, the use of green plants for the in situ treatment of contaminants, may be the most appropriate means ...


Source Localization From Received Signal Strength Under Lognormal Shadowing, Sree Divya Chitte 2010 University of Iowa

Source Localization From Received Signal Strength Under Lognormal Shadowing, Sree Divya Chitte

Theses and Dissertations

This thesis considers statistical issues in source localization from the received signal strength (RSS) measurements at sensor locations, under the practical assumption of log-normal shadowing. Distance information of source from sensor locations can be estimated from RSS measurements and many algorithms directly use powers of distances to localize the source, even though distance measurements are not directly available. The first part of the thesis considers the statistical analysis of distance estimation from RSS measurments. We show that the underlying problem is inefficient and there is only one unbiased estimator for this problem and its mean square error (MSE) grows exponentially ...


Evaluation Of Selected Warm Mix Asphalt Additives, Nishant Mukeshkumar Sheth 2010 University of Iowa

Evaluation Of Selected Warm Mix Asphalt Additives, Nishant Mukeshkumar Sheth

Theses and Dissertations

Warm mix asphalt (WMA) is an emerging technology that can allow asphalt to be produced and compacted at a significantly lower temperature. In the past, a number of researchers evaluated various WMA mixtures using select testing procedures in the laboratory. However, none of them evaluated all four major WMA products and compared them against both control HMA and WMA mixtures without an additive using a comprehensive set of testing protocols. This thesis presents a comprehensive evaluation result of four major WMA additives regarding their tensile strength, moisture sensitivity, dynamic modulus and flow number.

The WMA specimens exhibited similar air voids ...


Finite Element Modeling Of Icd Lead Silicone Soft-Tips, Jose J. Lepe 2010 California Polytechnic State University - San Luis Obispo

Finite Element Modeling Of Icd Lead Silicone Soft-Tips, Jose J. Lepe

Master's Theses and Project Reports

Although highly underutilized by the medical device industry, Finite Element Analysis (FEA) in the development of new technologies is gaining popularity as regulatory bodies such as the Food and Drug Administration (FDA) begin to require additional proof of safety through scientific methods. Non-linear FEA allows engineers to realistically simulate the mechanical behavior of implants as seen in the in-vitro, or in some cases, the in-vivo configurations. The work presented in this report investigates how computational methods can be used to simulate the interaction of a St. Jude Medical silicone soft-tip as it passes through a Peel-Away Sheath (i.e. introducer ...


Regional Deposition Of Particles In An Image-Based Airway Model: Cfd Simulation And Left-Right Lung Ventilation Asymmetry, Andrew Ryan Lambert 2010 University of Iowa

Regional Deposition Of Particles In An Image-Based Airway Model: Cfd Simulation And Left-Right Lung Ventilation Asymmetry, Andrew Ryan Lambert

Theses and Dissertations

Regional deposition and ventilation of particles by generation, lobe and lung during steady inhalation in a computed tomography (CT) based human airway model are investigated numerically. The airway model consists of a seven-generation human airway tree, with oral cavity, pharynx and larynx. The turbulent flow in the upper respiratory tract is simulated by large-eddy simulation. The flow boundary conditions at the peripheral airways are derived from CT images at two lung volumes to produce physiologically-realistic regional ventilation. Particles with diameter less than 2.5 microns are selected for study because smaller particles tend to penetrate to the more distal parts ...


Quantitative Analysis Of Retinal Function In Early Stages Of Retinal Degeneration In The Rd1 Mouse, Erik Lee Nylen 2010 University of Iowa

Quantitative Analysis Of Retinal Function In Early Stages Of Retinal Degeneration In The Rd1 Mouse, Erik Lee Nylen

Theses and Dissertations

In this thesis, I use a range of techniques in computational neuroscience, communication theory, and electrophysiology to characterize functional changes that occur in early stages of retinal degeneration in the mouse. At post natal day 14, retinal ganglion cells in the rd1 mouse exhibit peculiar differences from age matched controls: an increased latency of responses to the onset of a light stimulus, decreased spike count in response to stimulus onset, increased spontaneous firing activity, and a decrease in information transmission. I propose this is due to an up-regulation of OFF bipolar cell excitation, a critical factor in functional changes seen ...


Spectroscopic Evidence For Interfacial Fe(Ii)-Fe(Iii) Electron Transfer In Clay Minerals, Michael Vernon Schaefer 2010 University of Iowa

Spectroscopic Evidence For Interfacial Fe(Ii)-Fe(Iii) Electron Transfer In Clay Minerals, Michael Vernon Schaefer

Theses and Dissertations

Although interfacial electron transfer has been shown to occur for sorbed Fe(II) and Fe-oxides, it is unclear if a similar reaction occurs between sorbed Fe(II) and Fe(III)-bearing clay minerals. Here, we use the isotope specificity of 57Fe Mössbauer spectroscopy to demonstrate electron transfer between sorbed Fe(II) and structural Fe(III) in a nontronite clay mineral (NAu-2). Appearance of an Fe(II) doublet in the NAu-2 spectra after reaction with aqueous 56Fe(II) (56Fe is transparent in Mössbauer spectra) provided evidence for reduction of structural Fe(III). Mössbauer spectra using enriched 57Fe(II) reveal that Fe ...


Mechanical And Optical Methods For Breast Cancer Imaging, Zhiguo Wang 2010 University of Iowa

Mechanical And Optical Methods For Breast Cancer Imaging, Zhiguo Wang

Theses and Dissertations

It has been recognized that mechanical and optical properties of tissues can be the indicators to identify and characterize breast tumors. The objective of this study is to develop new mechanical and optical modalities for qualification of the elastic and optical properties of normal and cancerous breast tissues.

First, a mammography-based elastography (called elasto-mammography) is proposed to generate the elastogram of breast tissues based on conventional X-ray mammography. The displacement information is extracted from mammography projections before and after breast compression. With the incorporation of the displacement measurements, an elastography reconstruction algorithm is specially developed to estimate the elastic moduli ...


Calculation Of Sensor Redundancy Degree For Linear Sensor Systems, Santhosh Govindaraj 2010 University of Iowa

Calculation Of Sensor Redundancy Degree For Linear Sensor Systems, Santhosh Govindaraj

Theses and Dissertations

The rapid developments in the sensor and its related technology have made automation possible in many processes in diverse fields. Also sensor-based fault diagnosis and quality improvements have been made possible. These tasks depend highly on the sensor network for the accurate measurements. The two major problems that affect the reliability of the sensor system/network are sensor failures and sensor anomalies. The usage of redundant sensors offers some tolerance against these two problems. Hence the redundancy analysis of the sensor system is essential in order to clearly know the robustness of the system against these two problems. The degree ...


Experimental And Theoretical Investigations Of Active Center Generation And Mobility In Cationic And Free-Radical Photopolymerizations, Cynthia Caroline Hoppe 2010 University of Iowa

Experimental And Theoretical Investigations Of Active Center Generation And Mobility In Cationic And Free-Radical Photopolymerizations, Cynthia Caroline Hoppe

Theses and Dissertations

Photopolymerization is considered an attractive alternative in many industries to traditional polymerization processes. The advantages of photopolymerization over other types of polymerization include elimination of heat sources, faster cure times, and reduction in the use of volatile organic solvents. Despite these environmental and cost-saving advantages, photopolymerizations have several limitations. Light attenuation can be a problem for systems containing pigments or fillers. The radiation source penetrates only to a shallow depth beneath the surface, limiting the thickness of strongly pigmented or filled coatings and films. Photopolymerization is also generally limited to systems with simple geometries that can be uniformly illuminated. Coatings ...


Development Of A High-Resolution Two-Dimensional Urban/Rural Flood Simulation, Jesse Alex Piotrowski 2010 University of Iowa

Development Of A High-Resolution Two-Dimensional Urban/Rural Flood Simulation, Jesse Alex Piotrowski

Theses and Dissertations

Numerical modeling of extreme flooding in an urban area in eastern Iowa is presented. Modeling is performed using SRH-2D, an unstructured grid, finite volume model that solves the depth-averaged shallow-water equations. Data from a photogrammetric stereo compilation, contour maps, a hydrographic survey and building records were used to create a digital elevation model depicting the river channel and floodplain. A spatially distributed Manning coefficient based on land cover classification, derived from aerial photography is also used. The model is calibrated with high-resolution inundation depth data derived from a 1 m light detection and ranging survey, collected during the falling limb ...


Cfd Prediction Of Ship Response To Extreme Winds And/Or Waves, Sayyed Maysam Mousaviraad 2010 University of Iowa

Cfd Prediction Of Ship Response To Extreme Winds And/Or Waves, Sayyed Maysam Mousaviraad

Theses and Dissertations

The effects of winds and/or waves on ship motions, forces, moments, maneuverability and controllability are investigated with URANS computations.

The air/water flow computations employ a semi-coupled approach in which water is not affected by air, but air is computed assuming the free surface as a moving immersed boundary. The exact potential solution of waves/wind problem is modified introducing a logarithmic blending in air, and imposed as boundary and initial conditions. The turbulent air flows over 2D water waves are studied to investigate the effects of waves on incoming wind flow. Ship airwake computations are performed with different ...


Design And Test Of A Multi-Camera Based Orthorectified Airborne Imaging System, Nicole Lynn Becklinger 2010 University of Iowa

Design And Test Of A Multi-Camera Based Orthorectified Airborne Imaging System, Nicole Lynn Becklinger

Theses and Dissertations

Airborne imaging platforms have been applied to such diverse areas as surveillance, natural disaster monitoring, cartography and environmental research. However, airborne imaging data can be expensive, out of date, or difficult to interpret. This work introduces an Orthorectified Airborne Imaging (OAI) system designed to provide near real time images in Google Earth. The OAI system consists of a six camera airborne image collection system and a ground based image processing system. Images and position data are transmitted from the air to the ground station using a point to point (PTP) data link antenna connection. Upon reaching the ground station, image ...


Predictions Of Saturated Hydraulic Conductivity Dynamics In A Midwestern Agricultural Watershed, Iowa, Yi-Jia Chang 2010 University of Iowa

Predictions Of Saturated Hydraulic Conductivity Dynamics In A Midwestern Agricultural Watershed, Iowa, Yi-Jia Chang

Theses and Dissertations

In this study, a physically-based, modeling framework was developed to predict saturated hydraulic conductivity Ksat) dynamics in the Clear Creek Watershed (CCW), IA. The modeling framework integrated selected pedotransfer functions (PTFs) and watershed models with geospatial tools. A number of PTFs and watershed models were examined to select the appropriate models that represent the study site conditions. Models selection was based on statistical measures of the models' errors compared to the Ksat field measurements conducted in CCW under different soil, climatic and land use conditions. The study has shown that combined Rosetta and the Water Erosion Prediction Project ...


Improving Rotorcraft Deceleration Guidance For Brownout Landing, Gregory Mason Neiswander 2010 University of Iowa

Improving Rotorcraft Deceleration Guidance For Brownout Landing, Gregory Mason Neiswander

Theses and Dissertations

The BOSS symbology for rotorcraft is specifically designed to provide the pilot with the necessary information and guidance to safely land in brownout environments. From the last BOSS study, issues were brought forth regarding the longitudinal velocity algorithm, which sets up a deceleration profile and commands the forward speed of the aircraft throughout the approach. Pilots commented that the algorithm lead the aircraft to be too slow for too long, effectively prolonging the brownout. Thus the purpose of this study was to investigate new algorithms to enable a faster approach with less time spent in brownout. The previous deceleration algorithm ...


Investigation Of The Effect Of Phosphate On Iron(Ii) Sorption To Iron Oxides, Cristina Paola Fernández-Baca 2010 University of Iowa

Investigation Of The Effect Of Phosphate On Iron(Ii) Sorption To Iron Oxides, Cristina Paola Fernández-Baca

Theses and Dissertations

Iron is ubiquitous in the environment mostly as stable iron hydr(oxides) such as hematite (α-Fe2O3) and goethite (α-FeOOH). The Fe(II)-Fe(III) redox couple plays a vital role in nutrient cycling, bacteria respiration, and contaminant removal. This redox couple, however, can be affected by external influences such as anion adsorption of sulfate, oxalate, and phosphate which can influence various goethite properties including the point of zero charge. This study attempts to determine the effect of phosphate sorption to a goethite surface and its subsequent influence on Fe(II) sorption. The objectives, specifically, were to quantify phosphate sorption on ...


A Sharp Interface Cartesian Grid Hydrocode, Shiv Kumar Sambasivan 2010 University of Iowa

A Sharp Interface Cartesian Grid Hydrocode, Shiv Kumar Sambasivan

Theses and Dissertations

Dynamic response of materials to high-speed and high-intensity loading conditions is important in several applications including high-speed flows with droplets, bubbles and particles, and hyper-velocity impact and penetration processes. In such high-pressure physics problems, simulations encounter challenges associated with the treatment of material interfaces, particularly when strong nonlinear waves like shock and detonation waves impinge upon them. To simulate such complicated interfacial dynamics problems, a fixed Cartesian grid approach in conjunction with levelset interface tracking is attractive. In this regard, a sharp interface Cartesian grid-based, Ghost Fluid Method (GFM) is developed for resolving embedded fluid, elasto-plastic solid and rigid (solid ...


Mechanism Of Co2 Inhibition In Insect Cell Culture, Sucheta Gowthami Vajrala 2010 University of Iowa

Mechanism Of Co2 Inhibition In Insect Cell Culture, Sucheta Gowthami Vajrala

Theses and Dissertations

The prominence of insect cell culture has grown rapidly due to its ability to produce baculovirus biopesticides and recombinant proteins using the Baculovirus Expression Vector System. A critical problem in the mass production of these products is CO2 accumulation to inhibitory levels within the bioreactor. The current research investigated the effect of elevated CO2 concentrations on insect cell growth and metabolism and the roles of oxidative stress and intracellular pH (pHi) in CO2 inhibition.

Spodoptera frugiperda Sf-9 insect cells were cultured in a 3 L bioreactor (1.2 L working volume) controlled at 20% air saturation ...


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