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Articles 511 - 540 of 762

Full-Text Articles in Architecture

An Exploratory Study Of Speed Limit Compliance In Missouri Work Zones, Mojtaba A. Mohammadi, Ghulam Bham, Hadi Khazraee May 2011

An Exploratory Study Of Speed Limit Compliance In Missouri Work Zones, Mojtaba A. Mohammadi, Ghulam Bham, Hadi Khazraee

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This study evaluated the speed compliance with the posted speed limit both quantitatively and qualitatively using objective and subjective data analysis. Free flow speed data for three work zones on I-44 in Missouri were used for the objective evaluation. Speeds analyzed for cars and trucks were distributed normally. Construction activity had a significant effect in reducing the speed of vehicles. Results indicate that the speeds of vehicles were statistically higher than the speed limit regardless of the construction activity, when the lane width was not reduced. the subjective evaluation investigated the drivers' perception of driving through the work zone by …

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Wave Passage And Ground Motion Incoherency Effects On Seismic Response Of An Extended Bridge, Aman M. Mwafy, Oh Sung Kwon, Amr Elnashai, Youssef M.A. Hashash May 2011

Wave Passage And Ground Motion Incoherency Effects On Seismic Response Of An Extended Bridge, Aman M. Mwafy, Oh Sung Kwon, Amr Elnashai, Youssef M.A. Hashash

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This paper investigates the implications of ground motion spatial variability on the seismic response of an extended highway bridge. an existing 59-span, 2,164-meter bridge with several bearing types and irregularity features was selected as a reference structure. the bridge is located in the New Madrid Seismic Zone and supported on thick layers of soil deposits. Site-specific bedrock input ground motions were selected based on a refined probabilistic seismic hazard analysis of the bridge site. Wave passage and ground motion incoherency effects were accounted for after propagating the bedrock records to the ground surface. the results obtained from inelastic response-history analyses …

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Postearthquake Recovery Of A Water Distribution System: Discrete Event Simulation Using Colored Petri Nets, Ronaldo Luna, Nandini Balakrishnan, Cihan H. Dagli Mar 2011

Postearthquake Recovery Of A Water Distribution System: Discrete Event Simulation Using Colored Petri Nets, Ronaldo Luna, Nandini Balakrishnan, Cihan H. Dagli

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Planning and preparedness is essential for any resilient infrastructure system. Modeling and simulation give engineers and planners a better understanding of the system and help them make better decisions. the objective of this study is to demonstrate an improved model for the disaster restoration process by using a discrete event simulation approach. the study also aims to help improve the post-earthquake restoration process by simulating restoration curves. in this paper, colored Petri nets are used to model the system and to simulate its behavior. the resource allocation after a rare event such as an earthquake differs from the resource allocation …

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Physical Impact Of Waterjet-Based Sediment Remediation On Benthic Organisms, Grace Harper, Andrew Curtis Elmore, Christopher Redell, Gavin Risley, Joel Gerard Burken Jan 2011

Physical Impact Of Waterjet-Based Sediment Remediation On Benthic Organisms, Grace Harper, Andrew Curtis Elmore, Christopher Redell, Gavin Risley, Joel Gerard Burken

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Adding Activated Carbon to Sediments Has Been Shown to Be an Effective Means of Reducing the Bioavailability of Certain Contaminants. the Current State of the Practice is to Mechanically Mix Activated Carbon to a Target Concentration of 3 Percent at Depths of Approximately 30 Cm using a Rotovator or Similar Construction Equipment. Waterjets Have Been Used to Cut Hard Material using a Mixture of Water and an Abrasive. If Activated Carbon is Substituted for the Abrasive, Waterjets Have the Potential to Use Surface Injection as a Replacement for Mechanical Mixing during Sediment Remediation. a Perceived Benefit of Waterjet-Based Sediment Remediation …

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High-Strength Selfconsolidating Concrete Girders Subjected To Elevated Compressive Fiber Stresses, Part 2: Structural Behavior, Jared E. Brewe, John J. Myers Jan 2011

High-Strength Selfconsolidating Concrete Girders Subjected To Elevated Compressive Fiber Stresses, Part 2: Structural Behavior, Jared E. Brewe, John J. Myers

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The design of prestressed concrete members is restricted by the requirement that the extreme compressive fiber stress at midspan be less than 60% of the concrete compressive strength at release of prestressing. the purported purpose of this limit is to provide serviceability performance, but it places unnecessary limits on the capability of the materials. for this research program, six prestressed concrete girders were produced with high-strength, self-consolidating concrete and subjected to elevated compressive fiber stress levels ranging from 65% to 84% of initial concrete compressive strength at release of prestressing. Part 1 of this series analyzed time-dependent prestress losses and …

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Reaction Rates Of Ozone And Terpenes Adsorbed To Model Indoor Surfaces, M. Springs, J. R. Wells, Glenn Morrison Jan 2011

Reaction Rates Of Ozone And Terpenes Adsorbed To Model Indoor Surfaces, M. Springs, J. R. Wells, Glenn Morrison

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Reaction rates and reaction probabilities have been quantified on model indoor surfaces for the reaction of ozone with two monoterpenes (Δ3-carene and d-limonene). Molar surface loadings were obtained by performing breakthrough experiments in a plug-flow reactor (PFR) packed with beads of glass, polyvinylchloride or zirconium silicate. Reaction rates and probabilities were determined by equilibrating the PFR with both the terpene and the ozone and measuring the ozone consumption rate. to mimic typical indoor conditions, temperatures of 20, 25, and 30°C were used in both types of experiments along with a relative humidity ranging from 10% to 80%. the molar surface …

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Special Section On Advanced Modeling And Numerical Simulations In Geomechanics, Louis Ge, Dar Hao Chen, Rafiqul Alam Tarefder Jan 2011

Special Section On Advanced Modeling And Numerical Simulations In Geomechanics, Louis Ge, Dar Hao Chen, Rafiqul Alam Tarefder

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

No abstract provided.

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Development Of A Waterjet System For Direct Delivery Of Granular Iron And Activated Carbon To Remediate Contaminated Aqueous Sediments, Gavin H.R. Risley, Andrew Curtis Elmore, Joel Gerard Burken, Grzegorz (Greg) Galecki Jan 2011

Development Of A Waterjet System For Direct Delivery Of Granular Iron And Activated Carbon To Remediate Contaminated Aqueous Sediments, Gavin H.R. Risley, Andrew Curtis Elmore, Joel Gerard Burken, Grzegorz (Greg) Galecki

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

While the Techniques and Technologies Associated with Contaminated Sediment Remediation Are Relatively Mature, There Are Several Issues Associated with These Practices that Make Them Unattractive. the Inability of Currently Used Mechanical Mixing Implements to Place Amendments in Aqueous Environments and their Intrusive Behavior toward Benthic Communities Are Just Two Examples of a Necessity for an Improved Delivery Method. Waterjets May Be a Viable Option for Placement of Particulate Remediation Amendments, Such as Activated Carbon and Granular Iron, at Depth. a Custom Waterjet Nozzle and Injection System Has Been Fabricated by the Authors to Examine This Delivery Concept. the Developed Injection …

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Localization Of Free-Spanning Damage Using Mode Shape Curvature, Guirong Yan, Xuelin Peng, Hong Hao Jan 2011

Localization Of Free-Spanning Damage Using Mode Shape Curvature, Guirong Yan, Xuelin Peng, Hong Hao

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This Study Proposes a Damage Indicator based on Mode Shape Curvature to Localize Free-Spanning Damage of Submarine Pipeline Systems. the Feasibility of Curvatures of Low-Frequency Mode Shapes for Localizing Free-Spanning Damage of Pipeline Systems is Discussed, and Damage Indicators based on Mode Shape Curvatures Are Proposed. the Efficacy of the Proposed Damage Indicators is Demonstrated by Numerical Simulations of Dynamic Responses of a Submarine Pipeline under Ambient Conditions with Considering the Real Subsea Environment. the Proposed Approach is Simple, Which Does Not Require Baseline Data, and Thus is Promising in Practical Applications. © 2011 Published under Licence by IOP Publishing …

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A Web-Based Learning Module For Teaching Gis Within The Context Of Environmental Engineering, Sirjana Dahal, Richard H. Hall, Glenn Morrison, Seth Paul Lamble, Ronaldo Luna Jan 2011

A Web-Based Learning Module For Teaching Gis Within The Context Of Environmental Engineering, Sirjana Dahal, Richard H. Hall, Glenn Morrison, Seth Paul Lamble, Ronaldo Luna

Business and Information Technology Faculty Research & Creative Works

There is a Growing Need for Teaching Geographical Information Systems (GIS) in Engineering Disciplines, Such as Environmental. However, There Has Been Limited Focus on GIS in Undergraduate Programs, Since It's Difficult to Fit a GIS Class into the Large Number of Class Requirements Already Included in Engineering Curricula. the Purpose of This Research is the Evaluation of Web-Based Learning Module Created by a Multidisciplinary Team at a Midwestern Technological Research University, Which Allows Instructors to Integrate GIS Instruction into Existing Courses. This Module is One Part of a Large-Scale National Science Foundation Funded Project in Which GIS Modules Are Being …

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Evaluation Of Hydraulic Efficiency Of Disinfection Systems Based On Residence Time Distribution Curves, Jordan M. Wilson, Subhas K. Venayagamoorthy Dec 2010

Evaluation Of Hydraulic Efficiency Of Disinfection Systems Based On Residence Time Distribution Curves, Jordan M. Wilson, Subhas K. Venayagamoorthy

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Hydraulic efficiency is a vital component in evaluating the disinfection capability of a contact system. Current practice evaluates these systems based upon the theoretical detention time (TDT) and the rising limb of the residence time distribution (RTD) curve. This evaluation methodology is expected because most systems are built based on TDT under a "black box" approach to disinfection system design. Within recent years, the proliferation of computational fluid dynamics (CFD) has allowed a more insightful approach to disinfection system design and analysis. Research presented in this study using CFD models and physical tracer studies shows that evaluation methods based upon …

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Evaluation Of Compacted Silt Characteristics By Ultrasonic Pulse Velocity Testing, Desislava Z. Slavova, David M. Weidinger, Adam F. Sevi, Louis Ge Dec 2010

Evaluation Of Compacted Silt Characteristics By Ultrasonic Pulse Velocity Testing, Desislava Z. Slavova, David M. Weidinger, Adam F. Sevi, Louis Ge

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Unintrusive measurement of field modulus and moisture content of roadway subgrade and fill materials greatly enhances field control during construction. Establishing a measurement method in a laboratory setting provides an initial assessment of a tool's possible usefulness in the field. an ultrasonic test system was used in this research in order to determine the wave velocities of cylindrical soil specimens in a laboratory setting in support of a Briaud Compactive Device (BCD) research project. the BCD is a non-destructive test method that can quickly determine soil modulus both in the laboratory and the field. Cylindrical soil samples of silt were …

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Design Charts For Retaining Walls In Seismic Areas, Yingwei Wu, Shamsher Prakash Dec 2010

Design Charts For Retaining Walls In Seismic Areas, Yingwei Wu, Shamsher Prakash

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Retaining walls have failed either by sliding away from the backfill or due to combined action of sliding and rocking displacements, during earthquakes. Performance based design of the retaining walls in seismic areas must account for the likely displacements, in addition to calculating the usual factors of safety against failure in bearing, sliding and overturning. a realistic model for estimating dynamic displacement has been developed, which accounts for the combined action of sliding and rocking and takes into consideration, non-linear soil stiffness in sliding, and rocking, geometrical and material damping in sliding, and rocking, and coupling effects. This model was …

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Seismic Performance Of Square Rc Bridge Columns Under Combined Loading Including Torsion With Low Shear, Q. Li, Abdeldjelil Belarbi, S. S. Prakash Nov 2010

Seismic Performance Of Square Rc Bridge Columns Under Combined Loading Including Torsion With Low Shear, Q. Li, Abdeldjelil Belarbi, S. S. Prakash

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

During earthquake excitations, reinforced concrete bridge columns can be subjected to a combination of axial load, shear force, flexural moments, and torsional moments. the torsional moment can be much more significant in columns of bridges that are skewed, curved, have unequal spans, or unequal column heights. Combined loading including torsion can result in complex flexural and shear failure of these bridge columns. This paper presents an experimental study on the seismic behavior of square reinforced concrete columns under combined cyclic flexural and torsional moments. the columns in this study were designed with an aspect ratio of six and tested under …

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Structural Health Monitoring Of Reinforced Concrete Columns Subjected To Reversed Cyclic Loading Using Innovative Smart Aggregates, Yashar Moslehy, Haichang Gu, Abdeljalil Belarbi, Y. L. Mo, Gangbing Song Nov 2010

Structural Health Monitoring Of Reinforced Concrete Columns Subjected To Reversed Cyclic Loading Using Innovative Smart Aggregates, Yashar Moslehy, Haichang Gu, Abdeljalil Belarbi, Y. L. Mo, Gangbing Song

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Structural health monitoring is an important issue for the maintenance of large-scale civil infrastructure, especially for bridge columns. in this paper, an innovative piezoceramic-Based approach is developed for the structural health monitoring of reinforced concrete columns. an innovative piezoceramic-Based device, smart aggregate, is utilized as a transducer for health monitoring purposes. to investigate the seismic behavior of RC bridge columns, structural health monitoring tests were performed on two bridge columns under combined reversed cyclic loading at Missouri University of Science and Technology. Experimental results show that the proposed smart aggregate-Based approach successfully evaluated the health status of concrete columns during …

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Web-Based Intelligent Computational Argumentation Based Conflict Resolution In Air Traffic Management, Xiaoqing Frank Liu, Ravi Santosh Arvapally, Hojong Baik, Rubal Wanchoo Nov 2010

Web-Based Intelligent Computational Argumentation Based Conflict Resolution In Air Traffic Management, Xiaoqing Frank Liu, Ravi Santosh Arvapally, Hojong Baik, Rubal Wanchoo

Computer Science Faculty Research & Creative Works

Collaborative decision making (CDM) is a process of reaching consensus on a potential solution of an issue through the evaluation of the different possible alternatives. the web-Based intelligent computational argumentation system allows concerned stakeholders to post their arguments on different alternatives, assign weights and priorities to the arguments and reach the most favorable alternative using fuzzy intelligent techniques over the Internet. Exchange of information among the stakeholders improves the collaboration and drives towards the collective intelligence. in this paper, we show how our tool facilitates resolution of conflicts in air traffic management. It could enhance the Ground Delay Program (GDP) …

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Research Agenda For Transportation Infrastructure Preservation And Renewal: Conference Report, Joseph L. Schofer, Leonard Evans, Michael P. Freeman, Larry L. Galehouse, Samer Madanat, Ali Maher, Sue Mcneil, John J. Myers, Robert L. Peskin, Butch Wlaschin Nov 2010

Research Agenda For Transportation Infrastructure Preservation And Renewal: Conference Report, Joseph L. Schofer, Leonard Evans, Michael P. Freeman, Larry L. Galehouse, Samer Madanat, Ali Maher, Sue Mcneil, John J. Myers, Robert L. Peskin, Butch Wlaschin

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

No abstract provided.

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Foundations For Dynamic Loads, Vijay K. Puri, Shamsher Prakash Oct 2010

Foundations For Dynamic Loads, Vijay K. Puri, Shamsher Prakash

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Design of foundations in earthquake prone areas needs special considerations. Shallow foundations may experience a reduction in bearing capacity and increase in settlement and tilt due to seismic loading. the reduction in bearing capacity depends on the nature and type of soil and ground acceleration parameters. in the case of piles, the soil-pile behavior under earthquake loading is generally nonlinear. the nonlinearity must be accounted for by defining soil-pile stiffness in terms of strain dependent soil modulus. a comparison of observed and predicted pile behavior under dynamic loads has attracted the attention of several investigators. the lateral dynamic pile response …

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Seismic Assessment Of An Existing Non-Seismically Designed Major Bridge-Abutment-Foundation System, Aman Mwafy, Oh Sung Kwon, Amr Elnashai Aug 2010

Seismic Assessment Of An Existing Non-Seismically Designed Major Bridge-Abutment-Foundation System, Aman Mwafy, Oh Sung Kwon, Amr Elnashai

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

A comprehensive study carried out to assess the seismic response of a 59-span bridge using a refined inelastic modeling approach and considering Soil-Structure Interaction (SSI) is summarized in this paper. the focus is on describing the methodology adopted to idealize the bridge and its foundation system, while only highlights from the extensive elastic and inelastic analyses are presented. the bridge represents a typical case of vulnerable complex bridges since it was built in the early seventies with minimal seismic design requirements at a distance of about 5 km from a major fault. the SSI analysis is significant in this study …

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Cyber-Physical Codesign Of Distributed Structural Health Monitoring With Wireless Sensor Networks, Gregory Hackmann, Weijun Guo, Guirong Yan, Chenyang Lu, Shirley Dyke Jul 2010

Cyber-Physical Codesign Of Distributed Structural Health Monitoring With Wireless Sensor Networks, Gregory Hackmann, Weijun Guo, Guirong Yan, Chenyang Lu, Shirley Dyke

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Our Deteriorating Civil Infrastructure Faces the Critical Challenge of Long-Term Structural Health Monitoring for Damage Detection and Localization. in Contrast to Existing Research that Often Separates the Designs of Wireless Sensor Networks and Structural Engineering Algorithms, This Paper Proposes a Cyber-Physical Co-Design Approach to Structural Health Monitoring based on Wireless Sensor Networks. Our Approach Closely Integrates (1) Flexibility-Based Damage Localization Methods that Allow a Tradeoff between the Number of Sensors and the Resolution of Damage Localization, and (2) an Energy-Efficient, Multi-Level Computing Architecture Specifically Designed to Leverage the Multi-Resolution Feature of the Flexibility-Based Approach. the Proposed Approach Has Been Implemented …

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Low Viscosity Pore Fluid To Manufacture Transparent Soil, Honghua Zhao, Louis Ge, Ronaldo Luna Jul 2010

Low Viscosity Pore Fluid To Manufacture Transparent Soil, Honghua Zhao, Louis Ge, Ronaldo Luna

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Transparent soil has been investigated for its potential as a substitute research media for natural soil. the mechanism for manufacturing the transparent soil is through adding an appropriate pore fluid to silica gel particles with the same refractive index. Two types of high viscosity pore fluids were identified by Iskander in 1994. However, because of the high viscosity of these two pore fluids, air was easily entrapped, which made the manufacture of a large mass of transparent soil difficult. in addition, the identified pore fluids caused serious membrane deterioration during triaxial laboratory testing. This research presented herein is an experimental …

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Static And Fatigue Bond Characteristics Of Frp Rebars Embedded In Fiber-Reinforced Concrete, Huanzi Wang, Abdeldjelil Belarbi Jun 2010

Static And Fatigue Bond Characteristics Of Frp Rebars Embedded In Fiber-Reinforced Concrete, Huanzi Wang, Abdeldjelil Belarbi

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

A research project was initiated to develop a nonferrous hybrid reinforcement system for concrete bridge decks by using continuous fiber-reinforced polymer (FRP) rebars and discrete randomly distributed polypropylene fibers. This hybrid system may eliminate problems related to the corrosion of steel reinforcement while providing requisite strength, stiffness, and desired ductility, which are shortcomings of FRP reinforcing system in plain concrete. This article presents the results of a part of this research program, i.e., the bond behaviors of this hybrid reinforcing system under monotonic and fatigue loading. Test results indicate that the addition of polypropylene fibers does not increase the ultimate …

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Structural Damage Detection Robust Against Time Synchronization Errors, Guirong Yan, Shirley J. Dyke May 2010

Structural Damage Detection Robust Against Time Synchronization Errors, Guirong Yan, Shirley J. Dyke

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Structural Damage Detection based on Wireless Sensor Networks Can Be Affected Significantly by Time Synchronization Errors among Sensors. Precise Time Synchronization of Sensor Nodes Has Been Viewed as Crucial for Addressing This Issue. However, Precise Time Synchronization over a Long Period of Time is Often Impractical in Large Wireless Sensor Networks Due to Two Inherent Challenges. First, Time Synchronization Needs to Be Performed Periodically, Requiring Frequent Wireless Communication among Sensors at Significant Energy Cost. Second, Significant Time Synchronization Errors May Result from Node Failures Which Are Likely to Occur during Long-Term Deployment over Civil Infrastructures. in This Paper, a Damage …

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Investigation Of The Thermal Conductivity Of Compacted Silts And Its Correlation To The Elastic Modulus, Robert D. Hotz, Louis Ge Apr 2010

Investigation Of The Thermal Conductivity Of Compacted Silts And Its Correlation To The Elastic Modulus, Robert D. Hotz, Louis Ge

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Thermal conductivity measurement is a quick and easy test for compacted soils. This study presents the results of thermal conductivity testing on silt compacted under standard and modified Proctor efforts. a comparison of moisture content measurements from both lab oven and field oven is also presented and discussed. Measured thermal conductivity was correlated to the bulk density and water content. It is further correlated to Young's modulus and Shear modulus of the compacted silt, which were determined through ultrasonic pulse velocity measurements. Several trends were observed which may be used to correlate soil thermal conductivity of the compacted silt to …

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On The Turbulent Prandtl Number In Homogeneous Stably Stratified Turbulence, Subhas K. Venayagamoorthy, Derek D. Stretch Feb 2010

On The Turbulent Prandtl Number In Homogeneous Stably Stratified Turbulence, Subhas K. Venayagamoorthy, Derek D. Stretch

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

In this paper, we derive a general relationship for the turbulent Prandtl number Prt for homogeneous stably stratified turbulence from the turbulent kinetic energy and scalar variance equations. A formulation for the turbulent Prandtl number, Prt, is developed in terms of a mixing length scale LM and an overturning length scale LE, the ratio of the mechanical (turbulent kinetic energy) decay time scale TL to scalar decay time scale Tp and the gradient Richardson number Ri. We show that our formulation for Prt is appropriate even for non-stationary (developing) stratified flows, since it does not include the reversible contributions in …

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Estimation Of Flight Delay Costs For U.S. Domestic Air Passengers, Hojong Baik, Tao Li, Naveen K. Chintapudi Jan 2010

Estimation Of Flight Delay Costs For U.S. Domestic Air Passengers, Hojong Baik, Tao Li, Naveen K. Chintapudi

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Evaluating the economic value of flight delays has always been a keen interest of research groups as well as of federal agencies such as the U.S. Department of Transportation and FAA. However, because of the complexity of the question as well as the incompleteness of available data sets, the estimation of flight delay costs is considered a challenging task in practice. This paper presents a method for estimating domestic air passengers' delay costs incurred by flight delays in U.S. airports. a unique feature of the method is that the costs incurred by flight delays relative to the original flight schedules …

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Some Comments On The Protection Of Lunar Habitats Against Damage From Meteoroid Impacts, William P. Schonberg, F. Schäfer, R. Putzar Jan 2010

Some Comments On The Protection Of Lunar Habitats Against Damage From Meteoroid Impacts, William P. Schonberg, F. Schäfer, R. Putzar

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The establishment of human habitats on the Moon and on Mars will require protecting them from the hazards of near-Earth and interplanetary space. in addition to solar radiation, another hazard to be faced by these habitats is the damage that can result from the high-speed impact of a meteoroid on a critical structural component. Therefore, lunar habitats and their accompanying support facilities need to be designed with adequate levels of protection that will allow them to also withstand the damage that can result from a meteoroid impact. in this paper we discuss some approaches to shielding for lunar habitats, focusing …

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Diapycnal Diffusivities In Homogeneous Stratified Turbulence, D. D. Stretch, S. K. Venayagamoorthy Jan 2010

Diapycnal Diffusivities In Homogeneous Stratified Turbulence, D. D. Stretch, S. K. Venayagamoorthy

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Quantifying diapycnal mixing in stably stratified turbulence is fundamental to the understanding and modeling of geophysical flows. Data of diapycnal mixing from direct numerical simulations of homogeneous stratified turbulence and from grid turbulence experiments, are analyzed to investigate the scaling of the diapycnal diffusivity. In these homogeneous flows the instantaneous diapycnal diffusivity is given exactly by Kd= ∈ρ/ (∂ ρ /∂z)2where ∈ρ is the dissipation rate of density fluctuations, and ∂ ρ /∂z is the mean density gradient. The diffusivity Kd may be expressed in terms of the large-scale properties of the turbulence as K d = γLE …

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Modeling Permanent Deformation Of Unbound Granular Materials Under Repeated Loads, Cheng Chen, Louis Ge, Jiansheng Zhang Jan 2010

Modeling Permanent Deformation Of Unbound Granular Materials Under Repeated Loads, Cheng Chen, Louis Ge, Jiansheng Zhang

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Finite-element analysis on a pavement structure under traffic loads has been a viable option for researchers and designers in highway pavement design and analysis. Most of the constitutive drivers used were nonlinear elastic models defined by empirical resilient modulus equations. Few isotropic/kinematic hardening elastoplastic models were used but applying thousands of repeated load cycles became computationally expensive. in this paper, a cyclic plasticity model based on fuzzy plasticity theory is presented to model the long-term behavior of unbound granular materials under repeated loads. the discussion focuses on the model parameters that control long-term behavior such as elastic shakedown. the performance …

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Evaluation Of A Web-Based Learning Tool For Teaching Gis Within The Context Of Transportation Engineering, Ashley Banaszek, Hong Sheng, Richard H. Hall, Ronaldo Luna, Ghulam Bham Jan 2010

Evaluation Of A Web-Based Learning Tool For Teaching Gis Within The Context Of Transportation Engineering, Ashley Banaszek, Hong Sheng, Richard H. Hall, Ronaldo Luna, Ghulam Bham

Business and Information Technology Faculty Research & Creative Works

An Exploratory Study Was Conducted to Evaluate a Web-Based Learning Module for Teaching Geographic Information Systems to Civil Engineering Students within the Context of a Problem Related to Crash Data Analysis. This Module is One Part of a National Science Foundation Course, Curricula, and Laboratory Improvement Project in Which GIS Modules Are Being Developed for Several Areas of Civil Engineering. the Module Was Used as a Laboratory Assignment in a Transportation Engineering Course. Two Days Later Students Completed Both an Objective Multiple-Choice Quiz over the Material Covered in the Lab and a Subjective Questionnaire. Quantitative Analysis Was Carried Out on …

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