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Articles 1621 - 1650 of 7869

Full-Text Articles in Civil and Environmental Engineering

Energy Analysis Of A Student-Designed Solar House, Samantha Wermager, Stuart Werner Baur Dec 2013

Energy Analysis Of A Student-Designed Solar House, Samantha Wermager, Stuart Werner Baur

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This paper presents the findings from an undergraduate research project concerning the energy efficiency, consumption, and generation of a 1000 ft2 (92.9 m2) solar house. The results were compared to a home of similar size and layout, built using traditional construction methods. The solar house was modeled after the Chameleon House: Missouri University of Science and Technology's 2013 entry in the U.S. Department of Energy Solar Decathlon. The efficiency of the design was analyzed using Energy-10 Version 1.8 software. For this comparison, a fictional American couple was created and a breakdown of their energy-use habits was recorded …

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Effect Of Fly Ash Replacement Level On The Fracture Behavior Of Concrete, Mahdi Arezoumandi, Jeffery S. Volz Dec 2013

Effect Of Fly Ash Replacement Level On The Fracture Behavior Of Concrete, Mahdi Arezoumandi, Jeffery S. Volz

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The production of portland cement-the key ingredient in concrete-generates a significant amount of carbon dioxide. However, due to its incredible versatility, availability, and relatively low cost, concrete is the most consumed manmade material on the planet. One method of reducing concrete's contribution to greenhouse gas emissions is the use of fly ash to replace a significant amount of the cement. This study presents the results of an experimental investigation that evaluates effect of fly ash replacement level on the fracture energy of concrete. This study includes four mixes with 0%, 30%, 50%, and 70%fly ash as a cement replacement. This …

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Mechanism Of Crumb Rubber Modifier Dissolution Into Asphalt Matrix And Its Effect On Final Physical Properties Of Crumb Rubber-Modified Binder, Amir Ghavibazoo, Magdy Abdelrahman, Mohyeldin Ragab Dec 2013

Mechanism Of Crumb Rubber Modifier Dissolution Into Asphalt Matrix And Its Effect On Final Physical Properties Of Crumb Rubber-Modified Binder, Amir Ghavibazoo, Magdy Abdelrahman, Mohyeldin Ragab

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Modification of asphalt by crumb rubber modifier (CRM) is mostly done through exchange of components between asphalt and CRM. At 160⁰ C and 10 Hz, CRM absorbs aromatics of asphalt and swells; however, at 220⁰ C and 50 Hz, CRM dissolves into the asphalt; this process leads to the release of different components of CRM including carbon black, fillers, and polymeric and oily components. Depending on interaction conditions, CRM dissolution is performed differently, and therefore the state and role of the released components can be different. In this research different mechanisms of dissolution of one size of CRM in asphalt …

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Smart Rocks And Wireless Communication System For Real-Time Monitoring And Mitigation Of Bridge Scour -- A Proof-Of-Concept Study, Genda Chen, David Pommerenke, Y. Rosa Zheng, Andriy V. Radchenko, Yan Tang, Brandon P. Schafer, Ying Huang, Z. L. Yang Dec 2013

Smart Rocks And Wireless Communication System For Real-Time Monitoring And Mitigation Of Bridge Scour -- A Proof-Of-Concept Study, Genda Chen, David Pommerenke, Y. Rosa Zheng, Andriy V. Radchenko, Yan Tang, Brandon P. Schafer, Ying Huang, Z. L. Yang

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This study aims to integrate commercial measurement and communication components into a scour monitoring system with magnets or electronics embedded in smart rocks, and evaluate and improve its performance in laboratory and field conditions for the movement of smart rocks. Properly-designed smart rocks were found to be automatically rolled into the very bottom of a scour hole and can give critical information about the maximum scour depth and effectiveness of rip-rap mitigation strategies. Four types of smart rock technologies were investigated in this proof-of-concept phase of study, including passive with embedded magnets, active with magneto-inductive communication, active with controllable magnet …

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Effect Of Fly Ash Replacement Level On The Shear Strength Of High-Volume Fly Ash Concrete Beams, Mahdi Arezoumandi, Jeffery S. Volz Nov 2013

Effect Of Fly Ash Replacement Level On The Shear Strength Of High-Volume Fly Ash Concrete Beams, Mahdi Arezoumandi, Jeffery S. Volz

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The production of Portland cement - the key ingredient in concrete - generates a significant amount of carbon dioxide. However, due to its incredible versatility, availability, and relatively low cost, concrete is the most consumed manmade material on the planet. One method of reducing concrete's contribution to greenhouse gas emissions is the use of fly ash to replace a significant amount of the cement. An experimental investigation was conducted to study the shear strength of full-scale beams constructed with high-volume fly ash concrete (HVFAC) - concrete with at least 50% of the cement replaced with fly ash - and conventional …

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2013 Scholarly Productivity Report, Missouri University Of Science And Technology Nov 2013

2013 Scholarly Productivity Report, Missouri University Of Science And Technology

Civil, Architectural and Environmental Engineering Scholarly Productivity Reports

No abstract provided.

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Postcyclic Behavior Of Low-Plasticity Silt With Limited Excess Pore Pressures, Shuying Wang, Ronaldo Luna, Junsheng Yang Nov 2013

Postcyclic Behavior Of Low-Plasticity Silt With Limited Excess Pore Pressures, Shuying Wang, Ronaldo Luna, Junsheng Yang

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This paper investigates the post cyclic behavior of low-plasticity silt with excess pore pressure ratio (Ru) less than 1. The testing specimens were prepared from Mississippi River Valley (MRV) silt. Full and no reconsolidation were allowed after specimens were subjected to various excess pore pressure ratios due to cyclic loading in a cyclic triaxial cell, and then monotonic shear tests were conducted. The effect of the Ru on shear strength and stiffness at small and large deformation was investigated. It was found that a Ru greater than 0.70 is a prerequisite of large increase in volumetric strain and undrained shear …

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Plants As Bio-Indicators Of Subsurface Conditions: Impact Of Groundwater Level On Btex Concentrations In Trees, Jordan Wilson, Rachel Bartz, Matt Limmer, Joel Gerard Burken Oct 2013

Plants As Bio-Indicators Of Subsurface Conditions: Impact Of Groundwater Level On Btex Concentrations In Trees, Jordan Wilson, Rachel Bartz, Matt Limmer, Joel Gerard Burken

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Numerous Studies Have Demonstrated Trees' Ability to Extract and Translocate Moderately Hydrophobic Contaminants, and Sampling Trees for Compounds Such as BTEX Can Help Delineate Plumes in the Field. However, When BTEX is Detected in the Groundwater, Detection in Nearby Trees is Not as Reliable an Indicator of Subsurface Contamination as Other Compounds Such as Chlorinated Solvents. Aerobic Rhizospheric and Bulk Soil Degradation is a Potential Explanation for the Observed Variability of BTEX in Trees as Compared to Groundwater Concentrations. the Goal of This Study Was to Determine the Effect of Groundwater Level on BTEX Concentrations in Tree Tissue. the Central …

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Phytotechnologies - Preventing Exposures, Improving Public Health, Heather F. Henry, Joel Gerard Burken, Raina M. Maier, Lee A. Newman, Steven Rock, Jerald L. Schnoor, William A. Suk Oct 2013

Phytotechnologies - Preventing Exposures, Improving Public Health, Heather F. Henry, Joel Gerard Burken, Raina M. Maier, Lee A. Newman, Steven Rock, Jerald L. Schnoor, William A. Suk

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Phytotechnologies Have Potential to Reduce the Amount or Toxicity of Deleterious Chemicals and Agents, and Thereby, Can Reduce Human Exposures to Hazardous Substances. as Such, Phytotechnologies Are Tools for Primary Prevention in Public Health. Recent Research Demonstrates Phytotechnologies Can Be Uniquely Tailored for Effective Exposure Prevention in a Variety of Applications. in Addition to Exposure Prevention, Plants Can Be Used as Sensors to Identify Environmental Contamination and Potential Exposures. in This Paper, We Have Presented Applications and Research Developments in a Framework to Illustrate How Phytotechnologies Can Meet Basic Public Health Needs for Access to Clean Water, Air, and Food. …

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The Bridge Newsletter Winter 2013, Missouri University Of Science And Technology Oct 2013

The Bridge Newsletter Winter 2013, Missouri University Of Science And Technology

The Bridge Newsletter

-Roof turned into teaching tool
-Prakash recognized
-Alumna of the Year
-Super Miners

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Development Of Long Carbon Fiber-Reinforced Concrete For Dynamic Strengthening, Zahra S. Tabatabaei, Jeffery S. Volz, Benjamin P. Gliha, Darwin I. Keener Sep 2013

Development Of Long Carbon Fiber-Reinforced Concrete For Dynamic Strengthening, Zahra S. Tabatabaei, Jeffery S. Volz, Benjamin P. Gliha, Darwin I. Keener

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This paper discusses the development and testing of long carbon fibers-fibers 75 mm long or longer-to improve the resistance of reinforced concrete to dynamic loading, such as blasts and impact. In the past, attempts to use long fibers in concrete have failed as a result of both balling (agglomeration) and poor dispersion of the fibers. In the present study, two types of long carbon fibers were developed and optimized for their use in reinforced concrete. The resulting long carbon fiber-reinforced concrete (LCFRC) was subsequently evaluated through impact and blast testing. Full-scale blast testing revealed that these fibers significantly increased the …

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Dynamic Nonlinearity And Nonlinear Single-Degree-Of-Freedom Model For Cable Net Glazing, Ruo Qiang Feng, Jihong Ye, Guirong Yan, Jin Ming Ge Sep 2013

Dynamic Nonlinearity And Nonlinear Single-Degree-Of-Freedom Model For Cable Net Glazing, Ruo Qiang Feng, Jihong Ye, Guirong Yan, Jin Ming Ge

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The Nonlinear Vibration Differential Equation and Vibration Frequency of Cable Net Glazing Subject to Earthquake Loading Was Determined, and a Geometrically Nonlinear Single-Degree-Of-Freedom Model for Cable Net Glazing Was Developed. the Nonlinear Response Spectra Were Established, and Nonlinear Time History Analysis with Finite Element (FE) Models Was Conducted to Verify Them. the Nonlinear Vibration Differential Equation and Frequency Obtained as Described in This Paper Provide a Basis for the Nonlinear Single-Degree-Of-Freedom Model for Cable Net Glazing. the Analytical Formula for the Nonlinear Frequency with a Simplified Expression is Highly Precise and Convenient for Use in Engineering Practice. for Larger-Amplitude Seismic …

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Report On Laboratory Testing Of Fastening Of Cfs Track To Concrete Base Materials With Pafs, With Revision, Ricardo Ramirez, Roger A. Laboube Sep 2013

Report On Laboratory Testing Of Fastening Of Cfs Track To Concrete Base Materials With Pafs, With Revision, Ricardo Ramirez, Roger A. Laboube

American Iron and Steel Institute (AISI) Specifications, Standards, Manuals and Research Reports (1946 - present)

The 2012 AISI S100 Section E5 includes design provisions for power-actuated fasteners (PAFs) for connection of cold-formed steel (CFS) to steel base materials. However, a need exists to develop an in-depth understanding when CFS wall tracks are attached to concrete base materials as part of interior and exterior wall framing applications. Current code requirements, as specified by ASCE 7 – 2010 Chapter 13 (Exception to Section 13.4.5), limit individual PAFs in nonstructural component connections as part of distributed systems, to a sustained tension service load of 90 lbs in concrete and 250 lbs in steel in Seismic Design Categories D, …

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Comparison Of Prestress Losses For Pedestrian Bridges Constructed With High-Strength Concrete And High-Strength Self-Consolidating Concrete, John J. Myers, Kurt E. Bloch Sep 2013

Comparison Of Prestress Losses For Pedestrian Bridges Constructed With High-Strength Concrete And High-Strength Self-Consolidating Concrete, John J. Myers, Kurt E. Bloch

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Abstract Two precast prestressed high-strength concrete and high-strength self-consolidating concrete pedestrian bridges were designed and erected in Rolla, Missouri, for an in situ investigative study to monitor time-dependent losses. Using the temperature and strain data monitored by the vibrating wire strain gauges within the beam cross sections, time-dependent losses were determined and compared between the bridges and various empirical expressions presented by AASHTO and the Precast/Prestressed Concrete Institute. © 2013 American Society of Civil Engineers.

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Distribution And Accumulation Of Trichloroethylene And Trichloroacetic Acid In Hybrid Poplars, Lucas Odom, Joel Gerard Burken, Lee Newman Sep 2013

Distribution And Accumulation Of Trichloroethylene And Trichloroacetic Acid In Hybrid Poplars, Lucas Odom, Joel Gerard Burken, Lee Newman

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Hybrid Poplar Trees Are Known to Take Up Trichloroethylene (TCE) into above Ground Tissues, Where It Degrades into the Metabolites Trichloroacetic Acid (TCAA), Dichloroacetic Acid, and Trichloroethanol and Where Parent Chlorinated Solvents Volatilize to the Atmosphere. based on This Knowledge, Numerous Phytoremediation Applications Have Been Implemented for TCE and Other Chlorinated Solvents. Sampling of Plant Tissues Has Proven Effective for Phytoforensic and Phytoscreening Applications in Assessing Sites and Evaluating the Efficacy of Phytoremediation. However, Little is Known About the Appropriate Exposure Times and Sampling Locations Required to Obtain an Accurate Assessment of TCE and Metabolites. in This Study, Hybrid Poplars …

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Numerical Simulation Of Vortex-Induced Vibration Of Two Circular Cylinders Of Different Diameters At Low Reynolds Number, Ming Zhao, Guirong Yan Aug 2013

Numerical Simulation Of Vortex-Induced Vibration Of Two Circular Cylinders Of Different Diameters At Low Reynolds Number, Ming Zhao, Guirong Yan

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Two-Degree-Of-Freedom Vortex-Induced Vibration (VIV) of Two Rigidly Coupled Circular Cylinders of Different Diameters at a Low Reynolds Number of 250 is Investigated Numerically. While the Diameter Ratio and the Mass Ratio Are Kept Constant, the Study is Focused on the Effect of the Position Angle of the Small Cylinder on the Lock-In Regime of the VIV. Simulations Are Carried Out for Position Angles Α of the Small Cylinder Ranging from 0° to 180° with an Interval of 22.5° and the Reduced Velocities Ranging from 1 to 15 with an Increment of 1. in Order to Find the Effect of the …

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Directional Phytoscreening: Contaminant Gradients In Trees For Plume Delineation, Matt A. Limmer, Mikhil K. Shetty, Samantha Markus, Ryan Kroeker, Beth L. Parker, Camilo Martinez, Joel Gerard Burken Aug 2013

Directional Phytoscreening: Contaminant Gradients In Trees For Plume Delineation, Matt A. Limmer, Mikhil K. Shetty, Samantha Markus, Ryan Kroeker, Beth L. Parker, Camilo Martinez, Joel Gerard Burken

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Tree Sampling Methods Have Been Used in Phytoscreening Applications to Delineate Contaminated Soil and Groundwater, Augmenting Traditional Investigative Methods that Are Time-Consuming, Resource-Intensive, Invasive, and Costly. in the Past Decade, Contaminant Concentrations in Tree Tissues Have Been Shown to Reflect the Extent and Intensity of Subsurface Contamination. This Paper Investigates a New Phytoscreening Tool: Directional Tree Coring, a Concept Originating from Field Data that Indicated Azimuthal Concentrations in Tree Trunks Reflected the Concentration Gradients in the Groundwater Around the Tree.To Experimentally Test This Hypothesis, Large Diameter Trees Were Subjected to Subsurface Contaminant Concentration Gradients in a Greenhouse Study. These Trees …

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Dynamic Properties Of Fine-Grained Soils Engineered With A Controlled Organic Phase, B. Bate, H. Choo, S. E. Burns Aug 2013

Dynamic Properties Of Fine-Grained Soils Engineered With A Controlled Organic Phase, B. Bate, H. Choo, S. E. Burns

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Soils with high organic content are frequently encountered beneath earthquake sensitive infrastructure, such as bridges or levees. Historically, the dynamic properties of these organically rich soils have been difficult to predict due to the heterogeneity of the natural organic matter that is found in natural soils, even though their response to dynamic loading remains critical to assessing the ongoing stability of the infrastructure. In this study, an experimental investigation was performed on a montmorillonite soil that was modified with a controlled organic phase. Quaternary ammonium cations were exchanged onto the soil particle surfaces through cation exchange with the clay's naturally …

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Relevance Of The Thorpe Length Scale In Stably Stratified Turbulence, Benjamin D. Mater, Simon M. Schaad, Subhas Karan Venayagamoorthy Jul 2013

Relevance Of The Thorpe Length Scale In Stably Stratified Turbulence, Benjamin D. Mater, Simon M. Schaad, Subhas Karan Venayagamoorthy

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Direct numerical simulations of stably stratified turbulence are used to compare the Thorpe overturn length scale, LT, with other length scales of the flow that can be constructed from large-scale quantities fundamental to shear-free, stratified turbulence. Quantities considered are the turbulent kinetic energy, k, its dissipation rate, ε, and the buoyancy frequency, N. Fundamental length scales are then the Ozmidov length scale, LO, the isotropic large scale, Lkε, and a kinetic energy length scale, LkN. Behavior of all three fundamental scales, relative to LT, is shown to be a function of the buoyancy strength parameter NTL, where TL = k/ε …

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Modified Time Of Setting Test For Fly Ash Paste And Fly Ash-Soil Mixtures, Xin Kang, Gi Chun Kang, Louis Ge Jul 2013

Modified Time Of Setting Test For Fly Ash Paste And Fly Ash-Soil Mixtures, Xin Kang, Gi Chun Kang, Louis Ge

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

A survey of current literature has revealed that the testing protocol for determining the time of setting of fly ash-soil mixtures is not available. Although the current ASTM standard recommends using the Vicat needle method with a water-to-fly ash weight ratio of 0.35, it was originally proposed for testing the time of setting of cement. The current study showed that the Vicat needle method yielded poor test results for some common fly ashes. Moreover, the water-to-fly ash weight ratio of 0.35 may not be appropriate for some fly ashes because the chemical components are varied in different fly ashes. Therefore, …

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Centrifuge Modeling And Mitigation Of Manhole Uplift Due To Liquefaction, Gi Chun Kang, Tetsuo Tobita, Susumu Iai, Louis Ge Jul 2013

Centrifuge Modeling And Mitigation Of Manhole Uplift Due To Liquefaction, Gi Chun Kang, Tetsuo Tobita, Susumu Iai, Louis Ge

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Because low-compacted trench backfill around a manhole is normally liquefiable, the manhole could suffer uplift damage associated with soil liquefaction during a strong earthquake. In this study, 22 dynamic centrifuge models were tested to investigate the response of a buried manhole subjected to a dynamic load. The models were tested under 20g, and a substitute pore fluid was used to avoid the scaling law conflict between the dynamic and diffusion processes. It was found that excess pore water pressure is one of the contributing factors to the magnitude of the manhole uplift. Using this result, new mitigation methods against the …

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Portable Pressure Device To Evaluate Lateral Formwork Pressure Exerted By Fresh Concrete, Ahmed F. Omran, Kamal H. Khayat Jul 2013

Portable Pressure Device To Evaluate Lateral Formwork Pressure Exerted By Fresh Concrete, Ahmed F. Omran, Kamal H. Khayat

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Use of a reliable and accurate measuring system to determine lateral pressure exerted on formwork by self-consolidating concrete can lead to economic and safe formwork systems. In this paper, a portable and field-compatible pressure device is developed to enable factors affecting lateral pressure of fresh concrete on formwork system to be explored prior to conducting onsite full-scale tests. The pressure device requires a sample of 16 L of fresh concrete to determine lateral pressure envelope that can be exerted by a concrete column of up to 13 m in height. The pressure device enables the simulation of such concrete head …

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Energy Dissipation Of Thin-Walled Cold-Formed Steel Members, David A. Padilla-Llano, Christopher D. Moen, Matthew Eatherton Jul 2013

Energy Dissipation Of Thin-Walled Cold-Formed Steel Members, David A. Padilla-Llano, Christopher D. Moen, Matthew Eatherton

American Iron and Steel Institute (AISI) Specifications, Standards, Manuals and Research Reports (1946 - present)

No abstract provided.

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Wind-Induced Torsion Vibration Of The Super High-Rise Building Of Shenzhen Energy Center, Feng Ruo-Qiang, Ye Jihong, Guirong Yan, Li Qing-Xiang, Yao Bin Jul 2013

Wind-Induced Torsion Vibration Of The Super High-Rise Building Of Shenzhen Energy Center, Feng Ruo-Qiang, Ye Jihong, Guirong Yan, Li Qing-Xiang, Yao Bin

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The Synchronous Multipoint Scanning System Technique in Wind Tunnel Tests and Random Vibration Theory Method Were Used to Analyze the Wind-Induced Torsion Vibration of Some Irregularly Shaped Super High-Rise Buildings in Downtowns. the Torsion Vibration Modes and the Spectra of Torsion Wind Load Were Studied, and the Proportions of Mean Wind Torsion, Inertia Torsion and the Mass Eccentricity Torsion Caused by Horizontal Inertia Forces Are Discussed. the Following Conclusions Can Be Drawn. First, the Third and Fourth Modes Have Torsion Vibration Shapes, and their Frequencies Are in the High-Energy Area of the Spectra of the Torsion Wind Load; the Third …

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Dynamics And Dislodgment From Pore Constrictions Of A Trapped Nonwetting Droplet Stimulated By Seismic Waves, Wen Deng, M. Bayani Cardenas Jul 2013

Dynamics And Dislodgment From Pore Constrictions Of A Trapped Nonwetting Droplet Stimulated By Seismic Waves, Wen Deng, M. Bayani Cardenas

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Seismic waves affect fluid flow and transport processes in porous media. Therefore, quantitative understanding of the role of seismic waves in subsurface hydrodynamics is important for the development of practical applications and prediction of natural phenomena. We present a theoretical fluid dynamics model to describe how low-frequency elastic waves mobilize isolated droplets trapped in pores by capillary resistance. The ability of the theoretical model to predict the critical mobilization amplitudes (Ac) and the displacement dynamics of the nonwetting droplet are validated against computational fluid dynamics (CFD) simulations. Our theory has the advantage of rapid calculation of Ac …

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North American Specification For The Design Of Cold-Formed Steel Structural Members, 2012 Edition, American Iron And Steel Institute Jun 2013

North American Specification For The Design Of Cold-Formed Steel Structural Members, 2012 Edition, American Iron And Steel Institute

American Iron and Steel Institute (AISI) Specifications, Standards, Manuals and Research Reports (1946 - present)

No abstract provided.

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Long-Term Low Do Enriches And Shifts Nitrifier Community In Activated Sludge, Guoqiang Liu, Jianmin Wang May 2013

Long-Term Low Do Enriches And Shifts Nitrifier Community In Activated Sludge, Guoqiang Liu, Jianmin Wang

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

In the activated sludge process, reducing the operational dissolved oxygen (DO) concentration can improve oxygen transfer efficiency, thereby reducing energy use. The low DO, however, may result in incomplete nitrification. This research investigated the long-term effect of low DO on the nitrification performance of activated sludge. Results indicated that, for reactors with 10- and 40-day solids retention times (SRTs), complete nitrification was accomplished after a long-term operation with a DO of 0.37 and 0.16 mg/L, respectively. Under long-term low DO conditions, nitrite oxidizing bacteria (NOB) became a better oxygen competitor than ammonia oxidizing bacteria (AOB) and, as a result, no …

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Uncertainty In Radar-Rainfall Composite And Its Impact On Hydrologic Prediction For The Eastern Iowa Flood Of 2008, Bong Chul Seo, Luciana K. Cunha, Witold F. Krajewski May 2013

Uncertainty In Radar-Rainfall Composite And Its Impact On Hydrologic Prediction For The Eastern Iowa Flood Of 2008, Bong Chul Seo, Luciana K. Cunha, Witold F. Krajewski

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Key Points A significant potential source of error exists in mosaicked radar-rainfall maps. Different radar calibration offsets lead to misestimation of rainfall amounts. Systematic error in rainfall significantly affects hydrologic predictions. This study addresses a significant potential source of error that exists in radar-rainfall maps that are combined using data from multiple WSR-88D radars of the Next Generation Radar (NEXRAD) national network in the United States. This error stems from different radar calibration offsets that create a border within discontinuous rainfall fields at the equidistance zone among radars. The discontinuity in rainfall fields could lead to misestimation of rainfall over …

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Evaluation Of Liquefaction Potential Of An Earth Dam Foundation Using In Situ Tests, Ikram Guettaya, Mohamed Ridha El Ouni Apr 2013

Evaluation Of Liquefaction Potential Of An Earth Dam Foundation Using In Situ Tests, Ikram Guettaya, Mohamed Ridha El Ouni

International Conference on Case Histories in Geotechnical Engineering

This paper presents a case study of liquefaction potential assessment carried out under an earth dam foundation in Tunisia. An emphasis was made on the exploration of geotechnical conditions and the interpretation of field tests results collected before and after soil densification using the vibrocompaction technique. The assessment of soil liquefaction susceptibility was made using deterministic and probabilistic simplified procedures developed from several case histories. Conclusively, the obtained results show that before vibrocompaction the soil was prone to the liquefaction hazard. However, after vibrocompaction, a significant improvement of the soil resistance reduces the liquefaction potential of the sandy foundation. Indeed, …

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An Investigation On The Stack Vibrations And Geotechnical Rehabilitation Solutions Case-Study: Khangiran Gas Refinery, Hadi Ghodrat, Abolfazl Yazdinejad, Javad Hosseini Masum, Mehdi Barjini Khabbaz, Arsalan Ghahramani Apr 2013

An Investigation On The Stack Vibrations And Geotechnical Rehabilitation Solutions Case-Study: Khangiran Gas Refinery, Hadi Ghodrat, Abolfazl Yazdinejad, Javad Hosseini Masum, Mehdi Barjini Khabbaz, Arsalan Ghahramani

International Conference on Case Histories in Geotechnical Engineering

The 75 (m) high stacks of the sulfur recovery units of Khangiran Gas Refinery in Iran exhibited significant levels of vibration in winds. Field observations reported that vibration occurred in the stacks 9 times during reel years. The longest vibration duration is 8 hours and maximum tip deflection is 1 (m). In most intensive vibration occurrence much amount of water exits from around of foundation and some crack is created in the structure. Stack diameter is 4.57 (m) at the bottom and 3.43 (m) at the top and its total weight is 182.3 (Ton). The octagonal foundation diameter is 14 …

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