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2006

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Segmental Dynamics Of Poly(Isopropyl Acrylate)-D7 On Silica, Piyawan Krisanangkura, Frank D. Blum Jan 2006

Segmental Dynamics Of Poly(Isopropyl Acrylate)-D7 On Silica, Piyawan Krisanangkura, Frank D. Blum

Chemistry Faculty Research & Creative Works

For a polymer film deposited on a surface, the strength of the surfacesegment interaction affects the mobility of polymer-chain segments. The selfconsistent field lattice model of Scheutjens and Fleer,1 based on mean-field lattice models of polymer at interfaces,2 has been used to describe the distribution of conformations of polymers on surfaces. Adsorbed-polymer segments may be classified as belonging to loops, trains or tails. There are different techniques used to study the molecular motion of the polymer including modulated differential scanning calorimetry (MDSC)3 and nuclear magnetic resonance (NMR).4,5 in this work, solid-state deuterium (2H) NMR was used to characterize the polymer …

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Segmental Mobility Of Chain Ends In Poly(Methyl Acrylate)-D3, Burak Metin, Frank D. Blum Jan 2006

Segmental Mobility Of Chain Ends In Poly(Methyl Acrylate)-D3, Burak Metin, Frank D. Blum

Chemistry Faculty Research & Creative Works

Better control of polymeric materials can be achieved with a thorough understanding of the dynamics of their constituents. In the present study, we consider polymer chains as composed of chain middles and chain ends. Even though chain ends do not comprise much of the sample by mass, they may play a crucial role in the ultimate properties of the polymers. Although chain ends have been assigned a higher mobility, as compared to chain middles, there have not been a large number of experimental studies that directly probe their mobility. Among those, the studies of Kitahara et al.1 and Miwa et …

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Separation And Quantification Of N-Acetylcysteine-Amide (Naca) By Hplc With Fluorescence Detection, Wei Wu, Glenn Goldstein, Craig D. Adams, Richard H. Matthews, Nuran Ercal Jan 2006

Separation And Quantification Of N-Acetylcysteine-Amide (Naca) By Hplc With Fluorescence Detection, Wei Wu, Glenn Goldstein, Craig D. Adams, Richard H. Matthews, Nuran Ercal

Chemistry Faculty Research & Creative Works

N-acetyl-l-cysteine (NAC) is a well-known antioxidant that is capable of facilitating glutathione (GSH) biosynthesis and replenishing intracellular GSH under oxidatively challenging circumstances. N-acetyl-cysteine-amide (NACA), the amide form of NAC, is a newly designed and synthesized thiol-containing compound which is believed to be more lipophilic and permeable through cell membranes than NAC. The metabolic and antioxidant effects of these compounds in vitro and in vivo are under investigation. However, an analytical method that can separate and quantify both compounds simultaneously is not yet available, to the best of our knowledge. Because of their structural similarities, the two compounds are difficult to …

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Synthesis And Thermal Behavior Of Poly(Methyl Acrylate) Attached To Silica By Surface-Initiated Atrp, Manikantan B. Nair, Frank D. Blum Jan 2006

Synthesis And Thermal Behavior Of Poly(Methyl Acrylate) Attached To Silica By Surface-Initiated Atrp, Manikantan B. Nair, Frank D. Blum

Chemistry Faculty Research & Creative Works

The modification of the surface of an object dictates the response of the object to an external environment.1 Surface-modified materials and nanoparticles have attracted immense interest due to the various desirable electronic, optical and magnetic properties they possess.2 Silica is widely used as an inorganic filler. Surface modification of the silica, with a variety of organic moieties, facilitates the utilization of silica in conjunction with organic systems. The resulting organic/inorganic hybrid materials have significant potential applications. This work reports the synthesis and characterization of modified silica, and poly(methyl acrylate) attached to the modified silica. An observation of the thermal behavior …

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Conformal Internal Coating Of Macroporous Co-Continuous Mcf-Silicas With Isocyanate Derived Polymers, Nicholas Leventis, Chariklia Sotiriou-Leventis, Xiaojiang Wang, Sudhir Mulik Jan 2006

Conformal Internal Coating Of Macroporous Co-Continuous Mcf-Silicas With Isocyanate Derived Polymers, Nicholas Leventis, Chariklia Sotiriou-Leventis, Xiaojiang Wang, Sudhir Mulik

Chemistry Faculty Research & Creative Works

Since their discovery in 1992,1,2 templating sol-gel silica with structuredirecting agents has resulted in new materials with ordered mesoporous (2-50 nm) structure that is investigated for application in areas as diverse as high surface area supports for caralysts or as nanostructured drug storage and release platforms.3 Structure-directing agents are typically surfactants ranging from cationic detergents such as alkyl-trimethylammonium salts with C8-C18 hydrocarbon chains to non-ionic tertiary amines, polyethylene oxide or amphiphilic triblock copolymers such as poly(ethyleneoxide)-blockpoly( propyleneoxide)-block-poly(ethyleneoxide) (e.g., Pluronic P123). Depending on the surfactant and the conditions (e.g., kind and concentration of catalyst) the structure of the mesopores may vary …

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Effect Of Processing Conditions On Chemical Makeup Of Di-Isocyanate Crosslinked Silica Aerogels, Mary Ann B. Meador, Nicholas Leventis, Lynn A. Capadona, Plousia Vassilaras Jan 2006

Effect Of Processing Conditions On Chemical Makeup Of Di-Isocyanate Crosslinked Silica Aerogels, Mary Ann B. Meador, Nicholas Leventis, Lynn A. Capadona, Plousia Vassilaras

Chemistry Faculty Research & Creative Works

Sol-gel derived silica aerogels are attractive candidates for many unique thermal, optical, catalytic, and chemical applications1 because of their low density and high mesoporosity. However, their inherent fragility has restricted their use to, for example, insulation in extreme temperature environments such as Mars. We have previously reported crosslinking the mesoporous silica structure of an aerogel with di-isocyanates reacted with silanols on the surface,2,3 or epoxies reacting with an amine decorated silica surface.4 Either approach has been shown to significantly increase the strength of the aerogel with only a small effect on density or porosity. Thus, these hybrid materials may be …

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Neural Network-Based Output Feedback Controller For Lean Operation Of Spark Ignition Engines, Brian C. Kaul, Jagannathan Sarangapani, J. A. Drallmeier, Jonathan B. Vance, Pingan He Jan 2006

Neural Network-Based Output Feedback Controller For Lean Operation Of Spark Ignition Engines, Brian C. Kaul, Jagannathan Sarangapani, J. A. Drallmeier, Jonathan B. Vance, Pingan He

Electrical and Computer Engineering Faculty Research & Creative Works

Spark ignition (SI) engines running at very lean conditions demonstrate significant nonlinear behavior by exhibiting cycle-to-cycle dispersion of heat release even though such operation can significantly reduce NOx emissions and improve fuel efficiency by as much as 5-10%. A suite of neural network (NN) controller without and with reinforcement learning employing output feedback has shown ability to reduce the nonlinear cyclic dispersion observed under lean operating conditions. The neural network controllers consists of three NN: a) A NN observer to estimate the states of the engine such as total fuel and air; b) a second NN for generating virtual input; …

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Neuro Control Of Nonlinear Discrete Time Systems With Deadzone And Input Constraints, Pingan He, Wenzhi Gao, Jagannathan Sarangapani Jan 2006

Neuro Control Of Nonlinear Discrete Time Systems With Deadzone And Input Constraints, Pingan He, Wenzhi Gao, Jagannathan Sarangapani

Electrical and Computer Engineering Faculty Research & Creative Works

A neural network (NN) controller in discrete time is designed to deliver a desired tracking performance for a class of uncertain nonlinear systems with unknown deadzones and magnitude constraints on the input. The NN controller consists of two NNs: the first NN for compensating the unknown deadzones; and the second NN for compensating the uncertain nonlinear system dynamics. The magnitude constraints on the input are modeled as saturation nonlinearities and they are dealt with in the Lyapunov-based controller design. The uniformly ultimate boundedness (UUB) of the closed-loop tracking errors and the neural network weights estimation errors is demonstrated via Lyapunov …

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Segmental Dynamics In Poly(Methyl Acrylate) On Silica: Molecular-Mass Effects, Burak Metin, Frank D. Blum Jan 2006

Segmental Dynamics In Poly(Methyl Acrylate) On Silica: Molecular-Mass Effects, Burak Metin, Frank D. Blum

Chemistry Faculty Research & Creative Works

The effect of molecular mass on the segmental dynamics of poly(methyl acrylate) (PMA) adsorbed on silica was studied using deuterium quadrupole-echo nuclear magnetic resonance (NMR) and modulated differential scanning calorimetry. Samples adsorbed on silica (all about 1.5 mg PMA/m2 silica) were shown to have more restricted segmental mobility, and higher Tg's, than the corresponding bulk PMA samples. Around the glass-transition region, adsorbed samples exhibited segmental mobility, which could be classified as heterogeneous due to a superposition of more-mobile and less-mobile components present in the deuterium NMR spectra. This heterogeneity was consistent with a motional gradient with more-mobile segments near the …

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Segmental Dynamics Of Poly(Vinyl Acetate)- D₃ Absorbed On Silica By Solid State 2hnmr: Effect Of Small Molecule Plasticizer, Rakesh R. Nambiar, Frank D. Blum Jan 2006

Segmental Dynamics Of Poly(Vinyl Acetate)- D₃ Absorbed On Silica By Solid State 2hnmr: Effect Of Small Molecule Plasticizer, Rakesh R. Nambiar, Frank D. Blum

Chemistry Faculty Research & Creative Works

There has been significant progress in understanding the behavior of polymeric thin films on surfaces. The change in the apparent glass transition temperature (Tg) of supported thin polymer films with thickness (Tg -nanoconfinement effect) has been widely studied over the last fifteen years. While many studies focused on the thickness dependence of Tg, there are other aspects which are important to understand in a nanoconfined polymer system. For example, polymeric photoresists contain small-molecule photoactive compounds, plasticizers, and processing aids. These components interact with the polymer chains and affect the segmental mobility, which, in turn, affects the Tg - nanoconfinement effect. …

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Novel Sum-Of-Sinusoids Simulation Models For Rayleigh And Rician Fading Channels, Chengshan Xiao, Y. Rosa Zheng, N. C. Beaulieu Jan 2006

Novel Sum-Of-Sinusoids Simulation Models For Rayleigh And Rician Fading Channels, Chengshan Xiao, Y. Rosa Zheng, N. C. Beaulieu

Electrical and Computer Engineering Faculty Research & Creative Works

The statistical properties of Clarke's fading model with a finite number of sinusoids are analyzed, and an improved reference model is proposed for the simulation of Rayleigh fading channels. A novel statistical simulation model for Rician fading channels is examined. The new Rician fading simulation model employs a zero-mean stochastic sinusoid as the specular (line-of-sight) component, in contrast to existing Rician fading simulators that utilize a non-zero deterministic specular component. The statistical properties of the proposed Rician fading simulation model are analyzed in detail. It is shown that the probability density function of the Rician fading phase is not only …

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On Discrete-Time Modeling Of Time-Varying Wssus Fading Channels, Christian Sgraja, Chengshan Xiao Jan 2006

On Discrete-Time Modeling Of Time-Varying Wssus Fading Channels, Christian Sgraja, Chengshan Xiao

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, we consider the serial concatenation of linear time-varying (LTV) systems and its impact on the discrete-time modeling of wide-sense stationary uncorrelated scattering (WSSUS) fading channels. By deriving an expression for the composite impulse response of the overall concatenated system, we find that unlike the time-invariant case, the concatenation of LTV systems is not commutative, i. e., the order of arrangement affects the overall impulse response. This has significant impact when a digital transmission over a time-varying fading channel, which is an LTV channel, is represented by an equivalent discrete-time model that incorporates both transmitter and receiver filters. …

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Operational Characteristics Of Wind Plants And Windfarms, Badrul H. Chowdhury Jan 2006

Operational Characteristics Of Wind Plants And Windfarms, Badrul H. Chowdhury

Electrical and Computer Engineering Faculty Research & Creative Works

A wide range of power generation technologies exist today, whose characteristics can vary significantly. Additionally, a diverse range of wind turbines are available in the market. With experienced wind developers taking the charge in installing multi-megawatt-size windfarms at a rapid pace, the role of wind power in electricity generation is bound to grow in significance in the coming years. This panel takes a critical look at the operating characteristics of existing and planned wind power generation systems and their relationship to interconnection requirements and performance standards.

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Power System Control With An Embedded Neural Network In Hybrid System Modeling, Seung-Mook Baek, Jung-Wook Park, Ganesh K. Venayagamoorthy Jan 2006

Power System Control With An Embedded Neural Network In Hybrid System Modeling, Seung-Mook Baek, Jung-Wook Park, Ganesh K. Venayagamoorthy

Electrical and Computer Engineering Faculty Research & Creative Works

The output limits of the power system stabilizer (PSS) can improve the system damping performance immediately following a large disturbance. Due to non-smooth nonlinearities from the saturation limits, these values cannot be determined by the conventional tuning methods based on linear analysis. Only ad hoc tuning procedures can been used. A feedforward neural network (FFNN) (with a structure of multilayer perceptron neural network) is applied to identify the dynamics of an objective function formed by the states, and thereafter to compute the gradients required in the nonlinear parameter optimization. Moreover, its derivative information is used to replace that obtained from …

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Decentralized Power Control With Implementation For Rfid Networks, Kainan Cha, Anil Ramachandran, David Pommerenke, Jagannathan Sarangapani Jan 2006

Decentralized Power Control With Implementation For Rfid Networks, Kainan Cha, Anil Ramachandran, David Pommerenke, Jagannathan Sarangapani

Electrical and Computer Engineering Faculty Research & Creative Works

In radio frequency identification (RFID) systems, the detection range and read rates will suffer from interference among high power reading devices. This problem grows severely and degrades system performance in dense RFID networks. In this paper, we investigate a suite of feasible power control schemes to ensure overall coverage area of the system while maintaining a desired read rate. The power control scheme and MAC protocol dynamically adjusts the RFID reader power output in response to the interference level seen locally during tag reading for an acceptable signal-to-noise ratio (SNR). We present novel distributed adaptive power control (DAPC) and probabilistic …

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Design And Implementation Of A Storage Management Method For Content Distribution, Chang-Soo Kim, Yu-Hyeon Bak, Sang-Min Woo, Won-Jae Lee, Nunm-Ok Gee, Hag-Young Kim Jan 2006

Design And Implementation Of A Storage Management Method For Content Distribution, Chang-Soo Kim, Yu-Hyeon Bak, Sang-Min Woo, Won-Jae Lee, Nunm-Ok Gee, Hag-Young Kim

Electrical and Computer Engineering Faculty Research & Creative Works

The SMART system is a special purpose server developed by ETRI and designed for efficient streaming services over high speed networks. The SMART server has one or more special purpose NS (Network-Storage) card. The NS card has several disks that store multimedia contents. However all of the multimedia contents to be serviced cannot be stored at the server. In this paper, we will describe the storage management mechanism in design and implementation aspects. With this storage management mechanism, the SMART server can provide effectiveness in managing storage and distributing some contents from a source station to streaming service servers.

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Dynamic Simulation Of A Mems Cantilever Switch, James W. Fonda, Steve Eugene Watkins Jan 2006

Dynamic Simulation Of A Mems Cantilever Switch, James W. Fonda, Steve Eugene Watkins

Electrical and Computer Engineering Faculty Research & Creative Works

The dynamic behavior of a micro-electro-mechanicalsystem (MEMS) cantilever switch is investigated. Overactuation of the switch can degrade bounce characteristics and reduce the lifetime of the contacts. This work concerns the development of a control system that limits the number of switch bounces and reduces the impact force on the beam tip. A limited mass-spring analysis of the tip-position is given and an associated control approach is applied. Input limiting, state-feedback, and adaptive control methods are compared. All results demonstrate improved switch bounce characteristics for the simplified beam model with the adaptive showing the best performance improvement. A comprehensive finite element …

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Fault-Tolerant Control For Sssc Using Neural Networks And Pso, Wei Qiao, Ganesh K. Venayagamoorthy, Ronald G. Harley Jan 2006

Fault-Tolerant Control For Sssc Using Neural Networks And Pso, Wei Qiao, Ganesh K. Venayagamoorthy, Ronald G. Harley

Electrical and Computer Engineering Faculty Research & Creative Works

No abstract provided.

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Gene Expression Data For Dlbcl Cancer Survival Prediction With A Combination Of Machine Learning Technologies, Rui Xu, Xindi Cai, Donald C. Wunsch Jan 2006

Gene Expression Data For Dlbcl Cancer Survival Prediction With A Combination Of Machine Learning Technologies, Rui Xu, Xindi Cai, Donald C. Wunsch

Electrical and Computer Engineering Faculty Research & Creative Works

Gene expression profiles have become an important and promising way for cancer prognosis and treatment. In addition to their application in cancer class prediction and discovery, gene expression data can be used for the prediction of patient survival. Here, we use particle swarm optimization (PSO) to address one of the major challenges in gene expression data analysis, the curse of dimensionality, in order to discriminate high risk patients from low risk patients. A discrete binary version of PSO is used for gene selection and dimensionality reduction, and a probabilistic neural network (PNN) is implemented as the classifier. The experimental results …

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Hierarchical Control Scheme For Two Static Compensators In The Brazilian 45-Bus Power System, Salman Mohagheghi, Ganesh K. Venayagamoorthy, Yamille Del Valle, Ronald G. Harley Jan 2006

Hierarchical Control Scheme For Two Static Compensators In The Brazilian 45-Bus Power System, Salman Mohagheghi, Ganesh K. Venayagamoorthy, Yamille Del Valle, Ronald G. Harley

Electrical and Computer Engineering Faculty Research & Creative Works

No abstract provided.

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Identification Of Svc Dynamics Using Wide Area Signals In A Power System, Ganesh K. Venayagamoorthy, Sandhya R. Jetti Jan 2006

Identification Of Svc Dynamics Using Wide Area Signals In A Power System, Ganesh K. Venayagamoorthy, Sandhya R. Jetti

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents the design of a wide area monitor (WAM) using remote area signals, such as speed deviations of generators in a power network, for identifying online the dynamics of a static var compensator (SVC). The design of the WAM is studied on the 12 bus FACTS benchmark system recently introduced. A predict-correct method is used to enhance the performance of the WAM during online operation. Simulation results are presented to show that WAM can correctly identify the dynamics of SVC in a power system for small and large disturbances. Such WAMs can be applied in the design of …

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International Working Group On Assurance Cases (For Security), S. Guerra, M. Masera, Ann K. Miller, C. B. Weinstock, R. E. Bloomfield Jan 2006

International Working Group On Assurance Cases (For Security), S. Guerra, M. Masera, Ann K. Miller, C. B. Weinstock, R. E. Bloomfield

Electrical and Computer Engineering Faculty Research & Creative Works

Critical systems are aptly named - from electric power to water and gas to the telephone system and the Internet, they're all critical to some aspect of our daily lives. We''re a networked society and as such, it's important to both know whether critical systems are trustworthy and be able to communicate, review, and debate the level of trust achieved in them. In the safety domain, explicit safety cases are increasingly required by law, regulations, and standards. In this article, we outline what a small, international group of experts, spanning various disciplines in safety, security, reliability, and critical infrastructure, been …

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Multiple Statcom Allocation And Sizing Using Particle Swarm Optimization, Ganesh K. Venayagamoorthy, J. C. Hernandez, Yamille Del Valle, Ronald G. Harley Jan 2006

Multiple Statcom Allocation And Sizing Using Particle Swarm Optimization, Ganesh K. Venayagamoorthy, J. C. Hernandez, Yamille Del Valle, Ronald G. Harley

Electrical and Computer Engineering Faculty Research & Creative Works

No abstract provided.

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Nanoporous Zeolite Thin Film-Based Fiber Intrinsic Fabry-Perot Interferometric Sensor For Detection Of Dissolved Organics In Water, Ning Liu, Juan Hui, Cunqiang Sun, Junhang Dong, Luzheng Zhang, Hai Xiao Jan 2006

Nanoporous Zeolite Thin Film-Based Fiber Intrinsic Fabry-Perot Interferometric Sensor For Detection Of Dissolved Organics In Water, Ning Liu, Juan Hui, Cunqiang Sun, Junhang Dong, Luzheng Zhang, Hai Xiao

Electrical and Computer Engineering Faculty Research & Creative Works

A fiber optic intrinsic Fabry-Perot interferometric (IFPI) chemical sensor was developed by fine-polishing a thin layer of polycrystalline nanoporous MFI zeolite synthesized on the cleaved endface of a single mode fiber. The sensor operated by monitoring the optical thickness changes of the zeolite thin film caused by the adsorption of organic molecules into the zeolite channels. The optical thickness of the zeolite thin film was measured by white light interferometry. Using methanol, 2-propanol, and toluene as the model chemicals, it was demonstrated that the zeolite IPFI sensor could detect dissolved organics in water with high sensitivity.

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Improving Melting Efficiency Through The Application Of New Refractory Materials, Kent D. Peaslee, Semen Naumovich Lekakh, Von Richards, Todd P. Sander, Jeffrey D. Smith, Mangesh Vibhandik Jan 2006

Improving Melting Efficiency Through The Application Of New Refractory Materials, Kent D. Peaslee, Semen Naumovich Lekakh, Von Richards, Todd P. Sander, Jeffrey D. Smith, Mangesh Vibhandik

Materials Science and Engineering Faculty Research & Creative Works

Ladle design and ladle practices have a significant effect on a foundry operation and product quality. Large steel temperature losses or instabilities in the pouring temperature are frequently compensated by tapping at higher temperatures dramatically increasing furnace and ladle lining wear, oxidation of the steel, alloying element losses, and energy consumption in steel melting. Ladle lining materials need to satisfy a complex array of often conflicting requirements. For example, ceramic materials for linings must possess a high strength at liquid steel temperatures to prevent erosion and crack formation. However, linings need to also have a low thermal conductivity which typically …

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Decreasing Electrical Energy Consumption Through Sic Additions, Kent D. Peaslee, Semen Naumovich Lekakh, Von Richards, John Carpenter, Chen Wang Jan 2006

Decreasing Electrical Energy Consumption Through Sic Additions, Kent D. Peaslee, Semen Naumovich Lekakh, Von Richards, John Carpenter, Chen Wang

Materials Science and Engineering Faculty Research & Creative Works

This paper summarizes results of industrial experiments investigating the introduction of supplemental chemical energy in Electric Arc Furnaces (EAF). Specifically, this research evaluates the effects of adding 0.4-0.6% of the scrap charge weight as SiC (10 lbs per scrap ton charged) in the EAF. SiC additions increase the available exothermic reactions during oxygen boiling in an attempt to reduce the electrical energy requirements. Results from 180 trial heats at two different steel foundries are highlighted and statistically evaluated. In both cases, the SiC additions had a measurable effect on decreasing the electrical energy consumption.

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Earthquake Hazard Input For Loss Estimation Study: St. Louis Highway System, Ronaldo Luna, David J. Hoffman, William T. Lawrence Jan 2006

Earthquake Hazard Input For Loss Estimation Study: St. Louis Highway System, Ronaldo Luna, David J. Hoffman, William T. Lawrence

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The long recurrence period and high consequence earthquakes events in the New Madrid Seismic Zone have caused some federal agencies (e.g., NEHRP, FHWA) to look at the more densely populated areas where higher seismic risk is present. This paper presents the data collection, interpretation, and analysis of the geotechnical information required for an earthquake loss estimation study in St. Louis metro area. The loss estimation study was limited to the highway transportation system, where only the major highways were considered. The project information was processed using a GIS, and the subsequent loss analysis was executed using the HAZUS-MH program.

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Liquefaction Effects On Lateral Pile Behavior For Bridges, Wei Zheng, Ronaldo Luna Jan 2006

Liquefaction Effects On Lateral Pile Behavior For Bridges, Wei Zheng, Ronaldo Luna

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

A coupled pile-soil-structure interaction (SPSI) analysis method is presented to study the liquefaction effects on lateral pile behavior of the highway bridges. Pile-soil interaction is simulated by the dynamic nonlinear p-y method including the effect of liquefaction. The liquefaction effects to the pile-soil interaction are taken into account by introducing a degradation multiplier to the p-y curve. The degradation multiplier is related to the excess pore water pressure buildup at the pile-soil interface. The SPSI analysis method is implemented into a Missouri highway bridge site near the New Madrid Seismic Zone (NMSZ) rift complex for future earthquake scenarios of Mw …

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Systems Approach For Estimating Field Moisture Content, Thomas M. Petry, Yuh-Puu Han, David Newton Richardson Jan 2006

Systems Approach For Estimating Field Moisture Content, Thomas M. Petry, Yuh-Puu Han, David Newton Richardson

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This paper describes a software tool developed for estimation of the field moisture content of subgrade materials. Subgrade behavior is directly related to its moisture content. Unfortunately, some approaches of estimating field moisture content are too complex to be used in routine design. In this paper, the authors attempt to provide an approach that is easy to use. The software presented here was developed using expert system approaches. It is capable of analyzing data entered by the users, and providing estimations to meet different scenarios. The information entered by the user is first examined for its reasonableness and accuracy. Then, …

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Transverse-Earthquake Induced Deformations Of A Bridge Approach Embankment In The New Madrid Seismic Zone, Wanxing Liu, Richard Wesley Stephenson, Ronaldo Luna Jan 2006

Transverse-Earthquake Induced Deformations Of A Bridge Approach Embankment In The New Madrid Seismic Zone, Wanxing Liu, Richard Wesley Stephenson, Ronaldo Luna

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

It is predicted that strong earthquakes, larger than M 7.0, may occur within next 50 years in the New Madrid Seismic Zone (NMSZ), the location of three of the most powerful earthquakes in United States history. Large displacements may occur during strong earthquakes that can cause an embankment to fail or lose its function. The hyperbolic stress-strain model with Masing rules was modified to account for strength and stiffness reduction due to change in the effective confining pressure. The Byrne model was combined with a hyperbolic model to calculate the pore water pressure caused by seismic shaking. This modified hyperbolic …

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