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Assessing The Hydraulics Of Water Heaters By Adding Fluoride As A Tracer To Inform Its Overall Effect On Water Quality, Christian A. Guerrero, William Schmidt, Antoine Aubeneau, Amisha D. Shah 2017 Universidad San Francisco de Quito

Assessing The Hydraulics Of Water Heaters By Adding Fluoride As A Tracer To Inform Its Overall Effect On Water Quality, Christian A. Guerrero, William Schmidt, Antoine Aubeneau, Amisha D. Shah

The Summer Undergraduate Research Fellowship (SURF) Symposium

As residential water heaters are the primary source of waterborne disease outbreaks in the U.S. there is a need to better understand how they are contributing to decreased water quality in buildings. Previous work has indicated that intermittent stagnation, low disinfection residual and operation temperatures promote the growth of pathogens in water heaters. The overall effect of hydrodynamics of water heaters on these factors remains unclear. Therefore, a tracer study was performed to determine the effect of and characterize hydraulics of the typical residential water heater on water quality. Controlling temperature and flow rate, a pilot-scale hot water system ...


Electrochemical Removal Of Lead In Water With Multi-Wall Carbon Nanotube Filters, Benjamin M. Stryker, Sol Park, Zhi Zhou 2017 Purdue University

Electrochemical Removal Of Lead In Water With Multi-Wall Carbon Nanotube Filters, Benjamin M. Stryker, Sol Park, Zhi Zhou

The Summer Undergraduate Research Fellowship (SURF) Symposium

Heavy metals, such as lead, are highly toxic and typical removal techniques are costly for household applications; causing serious public health risks and economic burdens. Previous studies using electrochemical filtration showed that singe-wall carbon nanotube membranes (SWCNTs) were effective at removing lead, but the use of less expensive multi-walled carbon nanotubes (MWCNTs) has not been fully explored. Therefore, there is a critical need to determine if MWCNTs are cost-effective for the removal of lead in water. The removal efficiency of lead(II) ions in an aqueous solution was evaluated in a flow-through filtration system over 50 minutes at 1.5 ...


Purdue Airsense: An Affordable Way To Measure And Study Air Pollution, Stephane Junior Nouafo Wanko, Shadi Tariq Azouz, Ruihang Du, Brandon Boor, Greg Michalski 2017 Hiram College

Purdue Airsense: An Affordable Way To Measure And Study Air Pollution, Stephane Junior Nouafo Wanko, Shadi Tariq Azouz, Ruihang Du, Brandon Boor, Greg Michalski

The Summer Undergraduate Research Fellowship (SURF) Symposium

Air pollution is a major health hazard worldwide, accounting for one-eighth of all deaths in 2012 (World Health Organization). Globally, there is a severe lack of ground-based spatiotemporal monitoring of gaseous and particulate air pollutants, particularly in Africa, South and Central America, and the Middle East. This is in great part due to the high costs of air quality instrumentation that meet accuracy and reliability criteria set by monitoring agencies. The air quality data that is available is often not presented to the public in a user-friendly manner. Taking advantage of recent developments in low-cost sensing technologies, an integrated sensor ...


Assessment Of The Ecosystem Services Of Rain Gardens, Hannah M. Hawrot, Dr. Sara McMillan, Rachel Scarlett 2017 Purdue University

Assessment Of The Ecosystem Services Of Rain Gardens, Hannah M. Hawrot, Dr. Sara Mcmillan, Rachel Scarlett

The Summer Undergraduate Research Fellowship (SURF) Symposium

Stormwater runoff from impervious surfaces contributes to degradation of urban stream ecosystems. Impacts include increased flooding, water quality impairment, and disruption of habitats. Rain gardens are a type of green infrastructure designed to mitigate the adverse effects of stormwater runoff by promoting evapotranspiration, reducing peak flows, and retaining pollutants. Rain gardens can provide additional ecosystem services, defined as benefits that ecosystems provide to people. This includes, but is not limited to, increasing biodiversity by providing habitat, creating green spaces for recreation, and storing carbon. To date, little research has been done integrating these multiple services. My research measured water quality ...


The Effect Of Reinforcing Bar Bend Radius On The Strength And Behavior Of Knee Joints, Xitong Zhou, Christopher S. Williams, Hwa Ching Wang 2017 Purdue University

The Effect Of Reinforcing Bar Bend Radius On The Strength And Behavior Of Knee Joints, Xitong Zhou, Christopher S. Williams, Hwa Ching Wang

The Summer Undergraduate Research Fellowship (SURF) Symposium

The strut-and-tie method (STM) is used by structural engineers to design discontinuity regions of reinforced concrete structures. Using STM, the stress distribution in a concrete member is expressed as a set of struts, ties, and nodes in a strut-and-tie model. These components are then proportioned and evaluated to develop an appropriate design. One type of node that appears in knee joints (i.e., frame corners) subjected to closing moments is referred to as a curved-bar node. Although curved-bar nodes represent a unique concentration of stresses in a structure, little research focused on curved-bar node design has been conducted. In response ...


Buckling Of Cylindrical Shells Under Wind Loading, Tianlong Sun, Eyas Azzuni, Sukru Guzey 2017 Purdue University

Buckling Of Cylindrical Shells Under Wind Loading, Tianlong Sun, Eyas Azzuni, Sukru Guzey

The Summer Undergraduate Research Fellowship (SURF) Symposium

Cylindrical shells such as aboveground steel storage tanks are widely used to store gases, chemicals and fuels. Stiffener rings are introduced to prevent cylindrical shells from buckling due to wind loads. The current top wind stiffener design rules used in the USA for such cylindrical storage tanks are specified in API 650. However, the design methodology of top stiffener rings is overly conservative. Therefore, relaxation of the design rules for the top stiffener is investigated in this study. The API 650 mandated top stiffener size was reduced to the same size as the mandated intermediate stiffener ring in this study ...


Viscoelastic Analysis And Fatigue Characterization Of Bituminous Materials In Two Length Scales Under The Influence Of Aging, Santosh Reddy Kommidi 2017 University of Nebraska-Lincoln

Viscoelastic Analysis And Fatigue Characterization Of Bituminous Materials In Two Length Scales Under The Influence Of Aging, Santosh Reddy Kommidi

Civil Engineering Theses, Dissertations, and Student Research

Fatigue cracking in asphalt concrete (AC) is of immense importance to pavement design and analysis because it is one of the most important forms of distress that can lead to structural failure in pavement. Once started, these types of cracks can be combined with other environmental factors leading to detrimental effects such as faster rates of pavement deterioration and shortened pavement life and functionality.

Currently AASHTO TP101, also known as linear amplitude sweep (LAS) specification, is being widely used to evaluate the ability of an asphalt binder to resist fatigue. The LAS method, although mechanistic in its approach, has certain ...


Simulation And Prediction Of The Groundwater Level In The Surrounding Area Of The Nebraska Management System Evaluation Area Site In Central Nebraska., Cesar Augusto Gomez Peña 2017 University of Nebraska-Lincoln

Simulation And Prediction Of The Groundwater Level In The Surrounding Area Of The Nebraska Management System Evaluation Area Site In Central Nebraska., Cesar Augusto Gomez Peña

Civil Engineering Theses, Dissertations, and Student Research

An efficient water budget is necessary to develop sustainable practices in irrigated lands and determine future trends. Despite a lack of detailed knowledge, climate change is found to profoundly influence groundwater resources through changes in groundwater recharge, groundwater elevation, and groundwater flow processes. Prediction of the groundwater level (GWL) under a changing climate is essential to improve agricultural management.

The goal of this research is to predict the GWL from 2056 to 2060 in the surrounding area of the MSEA. In order to achieve the target, the first research task is to develop a groundwater flow model and then simulate ...


Large Payload Hiad Systems: Development Of Computationally Efficient Modeling Strategies And Structural Investigations, Andrew C. Young 2017 University of Maine

Large Payload Hiad Systems: Development Of Computationally Efficient Modeling Strategies And Structural Investigations, Andrew C. Young

Electronic Theses and Dissertations

The hypersonic inflatable aerodynamic decelerator (HIAD) system under development by the National Aeronautics and Space Administration (NASA) has the potential to deliver the size of payloads to the Martian surface that will be necessary for future human-scale missions. An important step in realizing the promise of the HIAD system is to understand the structural behavior of this inflatable, textile, relatively compliant system. This is accomplished through structural testing and the development of structural modeling and analysis methodologies and tools. The structural modeling tools that have been developed to date utilize a continuum, shell-based finite element (FE) analysis approach. This methodology ...


Essays In Measuring, Controlling, And Coordinating Supply Chain Inventory And Transportation Operations, Payam Parsa 2017 University of Arkansas, Fayetteville

Essays In Measuring, Controlling, And Coordinating Supply Chain Inventory And Transportation Operations, Payam Parsa

Theses and Dissertations

Supply chain collaboration programs, such as continuous replenishment program (CRP), is among the most popular supply chain management practices. CRP is an arrangement between two partners in a supply chain to share information on a regular basis for lowering logistics costs while maintaining or increasing service levels. CRP shifts the replenishment responsibility to the upstream partner to avoid the bullwhip effect across the supply chain. This dissertation aims to quantify, measure, and expand the benefits of CRP for the purpose of reducing logistics cost and improving customer service. The developed models in this dissertation are all applied in different case ...


Mitigation And Evaluation Of Alkali-Silica Reaction (Asr) And Freezing And Thawing In Concrete Transportation Structures, Richard Albert Deschenes Jr. 2017 University of Arkansas, Fayetteville

Mitigation And Evaluation Of Alkali-Silica Reaction (Asr) And Freezing And Thawing In Concrete Transportation Structures, Richard Albert Deschenes Jr.

Theses and Dissertations

An evaluation of alkali-silica reaction (ASR) and freezing and thawing (F/T) in concrete transportation structures is presented along with mitigation methods for slowing the rate of deterioration in concrete. A combination of field and laboratory testing confirms ASR deterioration is exacerbated by exposure to F/T. Laboratory testing indicates an aggregate previously deemed inert to ASR, caused ASR deterioration in several concrete pavement and transportation structures. Existing standard test methods deem this aggregate safe for use in concrete. A modified test method shows the concrete can deteriorate rapidly when subjected to cycles of conditions promoting ASR and F/T ...


Optimization Of Concrete Mixtures For Use In Structural Elements, Waleed Almutairi 2017 University of Arkansas, Fayetteville

Optimization Of Concrete Mixtures For Use In Structural Elements, Waleed Almutairi

Theses and Dissertations

Portland cement is an essential ingredient in concrete. The use of cement is to enhance the strength as well as other hardened properties of concrete mixtures. Determining the accurate amount of cement is important because the required strength may not be achieved if not enough cement is used. By contrast, when using too much cement, concrete cracking may occur that leads to reducing durability. Researchers at the University of Arkansas (UA) have shown that many bridge decks achieve their 28 day design strength of 4000 psi by 7 days of age. Bridge decks having high strength may experience cracking, which ...


Geophysical Assessment Of Kinion Lake Dam, Tim Allen Moody 2017 University of Arkansas, Fayetteville

Geophysical Assessment Of Kinion Lake Dam, Tim Allen Moody

Theses and Dissertations

Geophysical methods including Capacitively-Coupled Resistivity (CCR), Electrical Resistivity Tomography/Imaging (ERT/ERI), Multichannel Analysis of Surface Waves (MASW) with Love and Rayleigh waves and a Full-Waveform Inversion (FWI) were performed on Kinion Lake Dam, an earth-filled embankment dam that has historically experienced significant seepage and internal erosion issues. Surveys were completed along the crest and downstream toe of the dam. Results from the surveys indicate that each method is capable of resolving the bedrock depth within 1-2 m of locations shown on previous drilling logs, though some discrepancies between the methods exist. A weathered bedrock layer is believed to have ...


Archival Water-Level Measurements: Recovering Historical Data To Help Design For The Future, Stefan A. Talke, David A. Jay 2017 Portland State University

Archival Water-Level Measurements: Recovering Historical Data To Help Design For The Future, Stefan A. Talke, David A. Jay

Civil and Environmental Engineering Faculty Publications and Presentations

Improving methods of assessing risk and designing structures to withstand extreme events and changing sea levels is a vital component of strategies for reducing risk to coastal resources and assets. An obvious approach to improving the statistical robustness of risk assessments is to increase the number, time span, and quality of available water-level data sets, and to assess trends and non-stationarity. In this report we discuss efforts to recover, digitize, and analyze hundreds of station-years of lost-and-forgotten tide data and other water-level measurements that extend back to the early 19th century. To date, more than 6,500 station-years of previously ...


Soil-Structure Interaction Effects On The Seismic Response Of Low-Rise Eccentrically Braced Frames, Luis Gerardo Buitrago Goyez 2017 University of Arkansas, Fayetteville

Soil-Structure Interaction Effects On The Seismic Response Of Low-Rise Eccentrically Braced Frames, Luis Gerardo Buitrago Goyez

Theses and Dissertations

The importance of soil-structure interaction (SSI) effects on the seismic response of

buildings has been long recognized and has been researched for over 40 years. However, SSI

analysis has only been applied in a few building projects because the fixed base condition is

considered to provide a conservative estimation for the response of buildings under seismic loads.

This assumption of a fixed base condition adopted by practitioners is not always conservative or

cost-effective, especially for rigid buildings over soft soils. Additionally, for the case of ductile

steel frames with eccentric configurations, the influence of SSI on their seismic performance has ...


Development Of Deep Site Specific And Reference Shear Wave Velocity Profiles In The Canterbury Plains, New Zealand, Michael Ryan Deschenes 2017 University of Arkansas, Fayetteville

Development Of Deep Site Specific And Reference Shear Wave Velocity Profiles In The Canterbury Plains, New Zealand, Michael Ryan Deschenes

Theses and Dissertations

Deep (typically >1000 m) shear wave velocity profiles were developed across the Canterbury basin at nine strong motion stations using a combination of active and passive surface wave methods and horizontal to vertical spectral ratio measurements. A multi-mode, multi-method joint inversion process, which included Rayleigh and Love wave dispersion and horizontal to vertical spectral ratio data, was used to estimate the shear wave velocity profiles at each site. A-priori geologic information was utilized in defining preliminary constraints on the complex geologic layering of the Canterbury basin. At sites where interbedded layers were present, velocity reversals were considered in the inversion ...


Molecular Dynamics Modeling And Simulation Of Bitumen Chemical Aging, Farshad Fallah 2017 University of Nebraska - Lincoln

Molecular Dynamics Modeling And Simulation Of Bitumen Chemical Aging, Farshad Fallah

Civil Engineering Theses, Dissertations, and Student Research

Chemical aging of asphalt binder leads to significant changes in its mechanical and rheological properties, resulting in poor pavement behavior and distress. Various laboratory methods have been used to simulate asphalt aging during the service life of the pavement. However, controversy exists regarding the capability of these methods to predict field aging, as various factors interact with the pavement during service and the mechanism behind aging is not fully understood. The two main outcomes of chemical aging are oxidation of asphalt molecules, and change in asphalt SARA (saturate, aromatic, resin, and asphaltene) fractions. Reaction of oxygen with asphalt components forms ...


The Effect Of Microencapsulated Phase-Change Material On The Compressive Strength Of Structural Concrete, Chad Norvell, David J. Sailor, Peter Dusicka 2017 Portland State University

The Effect Of Microencapsulated Phase-Change Material On The Compressive Strength Of Structural Concrete, Chad Norvell, David J. Sailor, Peter Dusicka

Peter Dusicka

Latent heat energy storage through phase-change materials (PCMs) is one possible strategy to control interior temperatures in buildings, improve thermal comfort, and passively reduce building energy use associated with heating and cooling. While PCMs integrated into building structure elements have been studied since the 1970s, challenges of integrating PCMs into building materials while maintaining their heat storage benefits have limited their application in practice. The recent introduction of microencapsulated phase-change materials provides the energy storage capability of PCMs in micron-scale, chemically-inert capsules that can be easily integrated into composite materials such as gypsum wallboard and concrete. The size and physical ...


Seismic Retrofit Benefit Considering Statewide Transportation Assessment, Selamawit Tesfayesus Mehary, Peter Dusicka 2017 Portland State University

Seismic Retrofit Benefit Considering Statewide Transportation Assessment, Selamawit Tesfayesus Mehary, Peter Dusicka

Peter Dusicka

The purpose of this study was to identify and demonstrate a methodology to prioritize bridges for retrofit in the State of Oregon. Given the limited resources available, retrofitting all vulnerable bridges in the foreseeable future would not be practical. Instead, a retrofit strategy needs to be developed to prioritize the inventory and enumerate the retrofit cost. In this study, a prioritization methodology used a holistic assessment of overall roadway system to consider highway route segments, rather than individual bridges. The overall assessment was based on a cost-benefit analysis including retrofit cost, expected economic loss (with or without retrofit) and social ...


Seismic Vulnerability Of Oregon State Highway Bridges: Mitigation Strategies To Reduce Major Mobility Risks, Albert Nako, Craig Shike, Jan Six, Bruce Johnson, Peter Dusicka, Selamawit Tesfayesus Mehary 2017 Oregon Department of Transportation

Seismic Vulnerability Of Oregon State Highway Bridges: Mitigation Strategies To Reduce Major Mobility Risks, Albert Nako, Craig Shike, Jan Six, Bruce Johnson, Peter Dusicka, Selamawit Tesfayesus Mehary

Peter Dusicka

The Oregon Department of Transportation and Portland State University evaluated the seismic vulnerability of state highway bridges in western Oregon. The study used a computer program called REDARS2 that simulated the damage to bridges within a transportation network. It predicted ground motions for a specific location and magnitude of earthquake, resulting bridge damage and the cost of the damage, as well as the cost to the public for traffic delays due to detours around damaged bridges. Estimated damage and delay costs were presented for major highways in the region.


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