Open Access. Powered by Scholars. Published by Universities.®

Engineering Commons™

Open Access. Powered by Scholars. Published by Universities.®

Missouri University of Science and Technology

Discipline
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 11821 - 11850 of 21751

Full-Text Articles in Engineering

An Interval Type-Ii Robust Fuzzy Logic Controller For A Static Compensator In A Multimachine Power System, Salman Mohagheghi, Ganesh K. Venayagamoorthy, Ronald G. Harley Jan 2006

An Interval Type-Ii Robust Fuzzy Logic Controller For A Static Compensator In A Multimachine Power System, Salman Mohagheghi, Ganesh K. Venayagamoorthy, Ronald G. Harley

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents a novel fuzzy logic based controller for a Static Compensator (STATCOM) connected to a power system. Type-II fuzzy systems are selected that enable the controller to deal with design uncertainties and the noise associated with the measurements in the power system. Interval type-II fuzzy is computationally more effective than the ordinary type-II fuzzy systems and is more suitable for the power network with fast changing dynamics. Using a proportional-integrator approach the proposed controller is capable of dealing with actual rather than deviation signals. The STATCOM is connected to a multimachine power system in order to provide extra …

Go to article

A Comparison Of Diode-Clamped And Cascaded Multilevel Converters For A Statcom With Energy Storage, Ying Cheng, Chang Qian, Mariesa Crow, Steven Pekarek, Stan Atcitty Jan 2006

A Comparison Of Diode-Clamped And Cascaded Multilevel Converters For A Statcom With Energy Storage, Ying Cheng, Chang Qian, Mariesa Crow, Steven Pekarek, Stan Atcitty

Electrical and Computer Engineering Faculty Research & Creative Works

The progression of distributed generation within a bulk power system will lead to the need for greater control of transmission-line power flows. Static synchronous compensators (STATCOMs) provide a power-electronics-based means of embedded control of transmission-line voltage and power flows. The integration of energy storage with a STATCOM can extend traditional STATCOM capabilities to four-quadrant power flow control and transient stability improvement. This paper discusses energy storage systems (ESSs) integrated with conventional and multilevel bidirectional power converters for a hybrid STATCOM/ESS. Conventional, diode-clamped, and cascaded multilevel converter-based STATCOM/ESSs are developed, and their performances for a variety of power system applications are …

Go to article

Controlling Performance Of Crumb Rubber-Modified Binders Through Addition Of Polymer Modifiers, Magdy Abdelrahman Jan 2006

Controlling Performance Of Crumb Rubber-Modified Binders Through Addition Of Polymer Modifiers, Magdy Abdelrahman

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The use of tire rubber as a modifier to enhance the properties of asphalt mixes through the wet process has proved to be a successful procedure, but full control of the properties of crumb rubber-modified binders has been a challenge. The literature indicates a wide variation on adding rubber to asphalt and that the degree of success of rubber modification in AC mixes depends on several factors, the majority of which relate to the method of mixing, storing, and transporting and to construction technologies. Understanding the nature of the interaction process between asphalt cement and crumb rubber-modifier (CRM) helps explain …

Go to article

Effectiveness Of Open-Graded Base Layer On Subgrade Moisture Regime And Overall Pavement Performance, Hassan Salem, Fouad Bayomy, Robert Smith, Magdy Abdelrahman Jan 2006

Effectiveness Of Open-Graded Base Layer On Subgrade Moisture Regime And Overall Pavement Performance, Hassan Salem, Fouad Bayomy, Robert Smith, Magdy Abdelrahman

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Rockcap (open-graded crushed aggregate with a nominal maximum size of 2.5 in.) base layer is commonly used in the construction of asphalt pavements in Idaho. The effectiveness of the rockcap layer on the subgrade moisture regime and the overall pavement performance were evaluated. Two pavement sites were selected in northern and southern regions of the state. At each site, two pavement sections that are identical and adjacent to each other were instrumented by temperature, frost, and moisture sensors using time domain reflectometry (TDR) probes. One was constructed by a well-graded 3/4-in. aggregate base, whereas the other was constructed by the …

Go to article

Improving Prediction Accuracy In Mechanistic-Empirical Pavement Design Guide, Scott Schram, Magdy Abdelrahman Jan 2006

Improving Prediction Accuracy In Mechanistic-Empirical Pavement Design Guide, Scott Schram, Magdy Abdelrahman

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Model calibration plays a fundamental role in the implementation of the mechanistic-empirical pavement design guide. The data used in the default calibration effort, which were afforded by the Long Term Pavement Performance (LTPP) database, have a network-level inference space. As implementation proceeds, state highway agencies may be inclined to calibrate at a local network level. However, with a focus on the calibration data set to local project-level conditions, model prediction error can be reduced further. Under this study, Nebraska Department of Roads Pavement Management System data were used to calibrate two design guide smoothness models at the local project level. …

Go to article

Cost-Effective, Structural Stay-In-Place Formwork System Of Fiber-Reinforced Polymer For Accelerated And Durable Bridge Deck Construction, Thomas E. Ringelstetter, Lawrence C. Bank, Michael G. Oliva, Jeffrey S. Russell, Fabio Matta, Antonio Nanni Jan 2006

Cost-Effective, Structural Stay-In-Place Formwork System Of Fiber-Reinforced Polymer For Accelerated And Durable Bridge Deck Construction, Thomas E. Ringelstetter, Lawrence C. Bank, Michael G. Oliva, Jeffrey S. Russell, Fabio Matta, Antonio Nanni

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This paper describes research on the evolution of a cost-effective, structural stay-in-place (SIP) formwork bridge deck system with an integrated modular three-dimensional fiber-reinforced polymer (FRF) reinforcement cage. Recent research conducted at the University of Wisconsin is reviewed to show the evolution of the reinforcing system to include an integral FRP SIP form. the evolution occurred through laboratory testing, which was followed by the design and construction of two bridge structures owned by the State of Wisconsin. Each structure used different FRP reinforcement and formwork. These projects pointed out the need for a competitive SIP formwork to be used in conjunction …

Go to article

Effects Of Facts Devices On A Power System Which Includes A Large Wind Farm, Wei Qiao, Ganesh K. Venayagamoorthy, Ronald G. Harley Jan 2006

Effects Of Facts Devices On A Power System Which Includes A Large Wind Farm, Wei Qiao, Ganesh K. Venayagamoorthy, Ronald G. Harley

Electrical and Computer Engineering Faculty Research & Creative Works

No abstract provided.

Go to article

Empirical Study Of An Unconstrained Modified Particle Swarm Optimization, Ganesh K. Venayagamoorthy, Phillip W. Moore Jan 2006

Empirical Study Of An Unconstrained Modified Particle Swarm Optimization, Ganesh K. Venayagamoorthy, Phillip W. Moore

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, an unconstrained modified particle swarm optimization (UMPSO) algorithm is introduced and studied empirically. Four well known benchmark functions, with asymmetric initial position values, are used as testing functions for the UMPSO algorithm. The UMPSO is a variation of the canonical PSO in which the velocity and position is unconstrained, an additional strategic component is added, and the social component term has been modified. The strategy component is used instead of varying parameters or mutation to enhance diversity in the swarm during the search. The UMPSO algorithm is then compared to results obtained from the constrained canonical PSO …

Go to article

Intentional Islanding And Adaptive Load Shedding To Avoid Cascading Outages, Badrul H. Chowdhury, H. Manjari Dola Jan 2006

Intentional Islanding And Adaptive Load Shedding To Avoid Cascading Outages, Badrul H. Chowdhury, H. Manjari Dola

Electrical and Computer Engineering Faculty Research & Creative Works

Predetermined islanding scenarios along with automated load shedding schemes are applied once a prospective cascading outage condition is predicted. If required, additional distributed generation at specified locations in the system is also determined. The choice of different islands along with loads to be shed is then made available to the operator so as to be armed for action in case the system security is compromised. Determination of line outages that lead to disastrous consequences, intentional islanding schemes, and load shedding schemes have been explored individually. A plan integrating these defense mechanisms coupled with the possibility of using distributed generation where …

Go to article

Unifying Value Methodology And Robust Design To Achieve Design For Six Sigma, Vivek K. Jikar, Elizabeth A. Cudney, Kenneth M. Ragsdell, Chuck T. Hui Jan 2006

Unifying Value Methodology And Robust Design To Achieve Design For Six Sigma, Vivek K. Jikar, Elizabeth A. Cudney, Kenneth M. Ragsdell, Chuck T. Hui

Engineering Management and Systems Engineering Faculty Research & Creative Works

The concept of product or system function is considered as described in the Taguchi System of Quality Engineering. the importance of transfer functions is also discussed, and a review of conventional value analysis techniques is given. This paper proposes a combination of the principles of robust design and value methodology to enable on-target functionality and direct cost allocation early in the product development process. the discussion on integration of value analysis principles in robust design methodology is provided considering the six-sigma environment. Copyright © 2006 SAE International.

Go to article

Electrochemical Deposition And Characterization Of Fe₃O₄ Films Produced By The Reduction Of Fe(Iii)-Triethanolamine, Hiten M. Kothari, Elizabeth A. Kulp, Steven J. Limmer, Philippe Poizot, Eric W. Bohannan, Jay A. Switzer Jan 2006

Electrochemical Deposition And Characterization Of Fe₃O₄ Films Produced By The Reduction Of Fe(Iii)-Triethanolamine, Hiten M. Kothari, Elizabeth A. Kulp, Steven J. Limmer, Philippe Poizot, Eric W. Bohannan, Jay A. Switzer

Chemistry Faculty Research & Creative Works

In this paper, we demonstrate that films of magnetite, Fe3O4, can be deposited by the electrochemical reduction of a Fe(III)-triethanolamine complex in aqueous alkaline solution. the films were deposited with a columnar microstructure and a [100] preferred orientation on stainless steel substrates. In-plane electrical transport and magnetoresistance measurements were performed on the films after they were stripped off onto glass substrates. the resistance of the films was dependent on the oxygen partial pressure. We attribute the increase in resistance in O2 and the decrease in resistance in Ar to the oxidation and reduction of grain …

Go to article

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 …

Go to article

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 …

Go to article

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 …

Go to article

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 …

Go to article

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; …

Go to article

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 …

Go to article

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 …

Go to article

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. …

Go to article

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.

Go to article

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 …

Go to article

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.

Go to article

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 …

Go to article

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.

Go to article

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.

Go to article

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 …

Go to article

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 …

Go to article

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.

Go to article

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.

Go to article

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 …

Go to article

First Prev Next Last