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Full-Text Articles in Engineering

Critical Path For Project Development, Steven Douglas Kreis, Bryan Gibson, Jeff Jasper, Christopher W. Van Dyke, Candice Y. Wallace, Rachel Catchings, Sarah M. Mccormack Nov 2019

Critical Path For Project Development, Steven Douglas Kreis, Bryan Gibson, Jeff Jasper, Christopher W. Van Dyke, Candice Y. Wallace, Rachel Catchings, Sarah M. Mccormack

Kentucky Transportation Center Research Report

Overseeing the delivery of highway projects at the Kentucky Transportation Cabinet (KYTC) requires the successful coordination of activities and inputs from multiple external agencies and members of the agency’s Project Development team, who have varied disciplinary backgrounds. Despite the complexity of project delivery, the Cabinet presently does not estimate hours and project milestone dates until after it has selected a design consultant. Moving forward KYTC should explore requiring consultants to develop a critical path method (CPM) schedule. To facilitate this process, this report describes a methodology for producing CPMs for design contracts/projects based on procedures outlined in A Guide to …


Proppant For Use In Hydraulic Fracturing To Stimulate A Well, Thomas Lee Robl, Anne Elizabeth Oberlink Oct 2019

Proppant For Use In Hydraulic Fracturing To Stimulate A Well, Thomas Lee Robl, Anne Elizabeth Oberlink

Center for Applied Energy Research Faculty Patents

A proppant for use in hydraulic fracturing to stimulate a well is provided. The proppant is fly ash particles having a mean particle size (d50) of between 45 μm and 150 μm and a size distribution defined by (d10) ≤ 5 μm and (d98) ≤ 250 μm.


Identification Of Bridges With Fracture-Prone Details, Theodore Hopwood Ii, Rick Younce, Sudhir Palle Oct 2019

Identification Of Bridges With Fracture-Prone Details, Theodore Hopwood Ii, Rick Younce, Sudhir Palle

Kentucky Transportation Center Research Report

Welded steel girder bridges can contain details that can high welding and service stresses and are termed constraintinduced fractures (CIF). The Kentucky Transportation Cabinet has steel bridges with weld details known to cause CIFs whose girders have experienced fracture events. The Cabinet’s bridge inventory was reviewed and additional candidate bridges with potential CIF details were identified. A review of bridge plans and pictures along with followup field investigations pinpointed bridges with CIF details that warrant up-close (i.e., arm’s length) inspections. Several uninspected bridges were identified as candidates for inspection to determine if they contain CIF details. Guidance is provided to …


Access Management Best Practices, Adam Kirk, Chris Van Dyke Oct 2019

Access Management Best Practices, Adam Kirk, Chris Van Dyke

Kentucky Transportation Center Research Report

Research has persistently demonstrated that adopting a systematic access management framework improves highway operations and bolsters safety. Many state transportation agencies have adopted formal access management programs to systematize the application of access management techniques, however, the Kentucky Transportation Cabinet (KYTC) been unable to institute such a program due to institutional, regulatory, and political constraints. Recognizing the benefits of judicious access management, the Cabinet asked researchers at the Kentucky Transportation Center (KTC) to identify access management best practices that are effective, can be easily implemented, and are compatible with existing statutes and regulations. After reviewing national-level and state-level guidance on …


Evaluation Of Guardrail Needs And Update Of Guardrail Rating Program, Brian K. Howell, William Nicholas Staats, Nancy Albright Sep 2019

Evaluation Of Guardrail Needs And Update Of Guardrail Rating Program, Brian K. Howell, William Nicholas Staats, Nancy Albright

Kentucky Transportation Center Research Report

The Kentucky Transportation Cabinet (KYTC) seeks to reduce the frequency of roadway departure crashes, which often prove fatal. Roadside barriers such as guardrail have proven effective at mitigating these crashes, however, the demand for installations is high throughout the state. KYTC must prioritize prospective guardrail locations to match available funds with the most critical, or unsafe, sites. The current guardrail rating program (GRP) was established in 1989 to identify and prioritize guardrail needs. Despite periodic updates, the existing program no longer meets the transportation industry’s safety guidelines and policies. The Kentucky Transportation Center (KTC) studied national and state guardrail practices …


Analysis Of Traffic Crash Data In Kentucky (2014-2018), Eric R. Green, Kenneth R. Agent, Paul A. Ross Sep 2019

Analysis Of Traffic Crash Data In Kentucky (2014-2018), Eric R. Green, Kenneth R. Agent, Paul A. Ross

Kentucky Transportation Center Research Report

Executive Summary

This report documents an analysis of traffic crash data in Kentucky for the years of 2014-2018. A primary objective of this study was to determine average crash statistics for Kentucky highways. Rates were calculated for various types of highways and for counties and cities. Difference criteria were used for exposure.

Average and critical numbers and rates of crashes were calculated for various types of highways in rural and urban areas. These rates used crashes identified on highways where traffic volumes were available. Improved methods of identifying crash locations have resulted in higher rates for the last couple of …


2019 Safety Belt Usage Survey In Kentucky, Erin Lammers-Staats, Kenneth R. Agent, Eric R. Green Sep 2019

2019 Safety Belt Usage Survey In Kentucky, Erin Lammers-Staats, Kenneth R. Agent, Eric R. Green

Kentucky Transportation Center Research Report

The objective of the survey summarized in this report was to establish a statewide safety belt usage rate in Kentucky for 2019. This rate can be compared to those determined from previous surveys. The 2019 statewide survey documents the continued effect associated with law enforcement, related education, and general public attitude.


Investigation Of The Accuracy Of Alcohol And Drug Involvement Reporting, William Nicholas Staats Sep 2019

Investigation Of The Accuracy Of Alcohol And Drug Involvement Reporting, William Nicholas Staats

Kentucky Transportation Center Research Report

Executive Summary

Researchers compared the 2013 to 2017 fatal crash data from the KSP database to the crash data from the FARS database to check the consistency and accuracy of alcohol and drug involvement reporting for drivers in the KSP database. The indications of alcohol and drug involvement in the FARS database were used as the ground truth due to the inclusion of laboratory test results confirming the presence of alcohol and/or drugs in a driver’s system. For the five-year study period, the indications for alcohol involvement were 85.8% consistent and the indications of drug involvement were 66.2% consistent between …


Measuring Congestion For Strategic Highway Investment For Tomorrow (Shift) Implementation (Pl-32), Mei Chen, Xu Zhang, Fahmida Rahman, Jacob Brashear, Reginald R. Souleyrette Jul 2019

Measuring Congestion For Strategic Highway Investment For Tomorrow (Shift) Implementation (Pl-32), Mei Chen, Xu Zhang, Fahmida Rahman, Jacob Brashear, Reginald R. Souleyrette

Kentucky Transportation Center Research Report

The Kentucky Transportation Cabinet (KYTC) has moved toward a data-driven decision-making process, the Strategic Highway Investment Formula for Tomorrow (SHIFT), to allocate funds for highway improvement projects. SHIFT requires that candidate projects be scored on five critical metrics: safety, asset management, congestion, economic growth, and benefit/cost analysis.

The measure of congestion used in SHIFT 2018 was a combination of volume-to-service flow ratio (VSF) and design hourly volume (DHV). VSF is a traditional performance measure developed based on limited data, primarily for sketch planning purposes. However, it does not accurately reflect the dynamics of traffic congestion of many facilities.

This report …


Rapid Repair Of Bridge Decks In Cold Weather, Abheetha Peiris, Issam E. Harik Jul 2019

Rapid Repair Of Bridge Decks In Cold Weather, Abheetha Peiris, Issam E. Harik

Kentucky Transportation Center Research Report

Using regular concrete or mortar to repair potholes in concrete bridge decks is typically infeasible in cold weather due to extended set and curing times. However, several commercially available rapid-set repair materials can be used at temperatures near or below freezing. This study evaluated five such materials to assess their properties and determine which are most suited to executing pothole repairs in cold weather. For each material, laboratory testing evaluated set times, compressive strength gains, and bond strength to existing concrete at three temperatures: 35°F, 15°F, and 0°F (1.7°C, -9.4°C, and -17.8°C, respectively). Testing identified Phoscrete as the repair material …


Truss Bridge Rehabilitation Prioritization, Abheetha Peiris, Issam E. Harik Jul 2019

Truss Bridge Rehabilitation Prioritization, Abheetha Peiris, Issam E. Harik

Kentucky Transportation Center Research Report

Kentucky’s inventory of historic steel truss bridges is declining rapidly. There are more than 150 historic truss bridges in the Kentucky Transportation Cabinet’s (KYTC) bridge inventory. Most of these bridges require maintenance to avoid replacement. However, prioritizing the rehabilitation of these bridges based on their historic importance is challenging. While AASHTO’s Guidelines for Historic Bridge Rehabilitation and Replacement contain guidance on selecting bridges for preservation, currently there is no guidance on how to prioritize those historic bridges selected for rehabilitation. Building on a previous study that identified historic truss bridges in Kentucky meriting preservation, the Kentucky Transportation Center (KTC) developed …


Edge Drain Performance, Kean H. Ashurst Jr., Brad W. Rister Jul 2019

Edge Drain Performance, Kean H. Ashurst Jr., Brad W. Rister

Kentucky Transportation Center Research Report

Edge drain systems are used on new highway construction projects and rehabilitation projects to reduce the moisture content of the pavement block and subgrade. Maintaining dry conditions in and around these components increases the subgrade strength and extends a pavement’s surface life. Edge drain systems can only operate effectively, however, if the entire subsurface drainage system functions properly. While many studies have demonstrated the benefits of edge drain systems, no comprehensive investigation of their performance has been undertaken in the state of Kentucky in over 20 years. After the Kentucky Transportation Cabinet (KYTC) identified problems with an edge drainage system …


Issues Pertaining To Rebuilt Vehicle Titles, Valerie J. Keathley, Andrew Martin, Jeeyen Koo, Jennifer R. Walton Jul 2019

Issues Pertaining To Rebuilt Vehicle Titles, Valerie J. Keathley, Andrew Martin, Jeeyen Koo, Jennifer R. Walton

Kentucky Transportation Center Research Report

In Kentucky, salvage titles are issued when a vehicle has been wrecked, destroyed, or damaged and the cost of repairs exceeds 75 percent of the vehicle’s fair market value. Once a vehicle is repaired to roadworthy condition it is issued a rebuilt title. Kentucky issued 110,000 rebuilt and salvage titles in 2018. Over the 2014 to 2018 period, the number of rebuilt and salvage titles issued climbed 31 percent. The economic impact of rebuilt and salvage titles in Kentucky is considerable — approximately $331 million in 2018, based on data for the taxable values or sales prices of vehicles.

To …


Rapid Retrofit And Strengthening Of Bridge Components, Abheetha Peiris, Issam E. Harik Jul 2019

Rapid Retrofit And Strengthening Of Bridge Components, Abheetha Peiris, Issam E. Harik

Kentucky Transportation Center Research Report

Rapid repair of damaged or deteriorated concrete bridge components will prevent the entire bridge from suffering irreversible damage in the future due to gradual spalling of concrete or corrosion of exposed steel. CFRP laminates and fabrics have become popular for repairing and strengthening of concrete girders. A series of CFRP materials — branded CatStrong — specifically designed for the repair and retrofit of bridges was developed at the Kentucky Transportation Center and the University of Kentucky. These materials include the CFRP Rod Panels (CatStrong CRPs), Unidirectional and Triaxial Carbon Fabric (CatStrong UCF and TCF), and Triaxial Carbon Wrap (CatStrong TCW). …


Safety Analysis For Shift Implementation, Reginald R. Souleyrette, Riana Tanzen, William Nicholas Staats, Eric R. Green, Mei Chen Jul 2019

Safety Analysis For Shift Implementation, Reginald R. Souleyrette, Riana Tanzen, William Nicholas Staats, Eric R. Green, Mei Chen

Kentucky Transportation Center Research Report

The Strategic Highway Investment Formula for Tomorrow (SHIFT) program research team evaluated the program’s 2018 safety component and developed a new methodology to rank the safety needs of 2020 projects. For the current year, the research team suggests replacing the SHIFT 2018 formulas (based on three naive crash measures) with a new metric, Excess Expected Crashes, formulated from the most current safety analysis guidelines available in the Highway Safety Manual. In addition, the research team developed a user-friendly network screening tool serving as a method to prioritize projects. Another automation tool was developed that will help safety professionals evaluate and …


A Traffic-Aware Approach For Enabling Unmanned Aerial Vehicles (Uavs) In Smart City Scenarios, Hesham El-Sayed, Moumena Chaqfa, Sherali Zeadally, Deepak Puthal Jun 2019

A Traffic-Aware Approach For Enabling Unmanned Aerial Vehicles (Uavs) In Smart City Scenarios, Hesham El-Sayed, Moumena Chaqfa, Sherali Zeadally, Deepak Puthal

Information Science Faculty Publications

In smart cities, vehicular applications require high computation capabilities and low-latency communication. Edge computing offers promising solutions for addressing these requirements because of several features, such as geo-distribution, mobility, low latency, heterogeneity, and support for real-time interactions. To employ network edges, existing fixed roadside units can be equipped with edge computing servers. Nevertheless, there are situations where additional infrastructure units are required to handle temporary high traffic loads during public events, unexpected weather conditions, or extreme traffic congestion. In such cases, the use of flying roadside units are carried by unmanned aerial vehicles (UAVs), which provide the required infrastructure for …


Nonlinear Dynamic Analysis Of Long-Span Cable-Stayed Bridges With Train-Bridge And Cable Coupling, Zhihui Zhu, Lidong Wang, Michael T. Davidson, Issam E. Harik, Anand Patil Jun 2019

Nonlinear Dynamic Analysis Of Long-Span Cable-Stayed Bridges With Train-Bridge And Cable Coupling, Zhihui Zhu, Lidong Wang, Michael T. Davidson, Issam E. Harik, Anand Patil

Civil Engineering Faculty Publications

Span lengths of newly constructed cable-stayed railway bridges continue to show increases relative to those of older bridges. Accompanying such increases is the importance of ensuring that vibrations of long-span cable-stayed bridges satisfy both safety and serviceability requirements, particularly for bridges that support train passages. In contrast to modern design of bridges that support roadway vehicles, current methods for analyzing cable-stayed railway bridges do not yet typically account for coupling effects that may occur between cables and the surrounding bridge structure during train passages. This paper presents a computational framework for the nonlinear dynamic analysis of railway bridges based on …


E-Tickets And Advanced Technologies For Efficient Construction Inspections, Roy E. Sturgill, Gabriel B. Dadi, Christopher Van Dyke, Dhaviat Patel, Joshua Withrow, Clyde Wesley Newcomer Iv Jun 2019

E-Tickets And Advanced Technologies For Efficient Construction Inspections, Roy E. Sturgill, Gabriel B. Dadi, Christopher Van Dyke, Dhaviat Patel, Joshua Withrow, Clyde Wesley Newcomer Iv

Kentucky Transportation Center Research Report

The Kentucky Transportation Cabinet (KYTC), like many state transportation agencies, has seen demand for high-quality infrastructure skyrocket even as it endures reductions in staff numbers. To mitigate the effects of declining staff and bolster construction efficiency, the Cabinet has experimented with a variety of e-construction technologies, the goal of which are to abolish paper-based workflows and improve project-site monitoring activities. This research investigated the performance of three e-construction technologies on KYTC pilot projects — e-ticketing, paver mounted thermal profilers, and intelligent compaction. E-ticketing reduced the amount of time needed to retrieve material tickets and facilitated comparisons of theoretical tonnages to …


Review Of Non-Standard Warm Mix Asphalt Projects, Tim C. Scully Jr. Jun 2019

Review Of Non-Standard Warm Mix Asphalt Projects, Tim C. Scully Jr.

Kentucky Transportation Center Research Report

Periodically, when the Kentucky Transportation Cabinet’s (KYTC) the Division of Construction receives requests to use non-standard warm mix asphalt technologies, it may be asked to waive the temperature specification or other product specifications/processes. The short-term and long-term impacts of this waiver are not completely understood. The Division of Construction approves these requests and notes their use, however, no follow-up studies have been done to evaluate the performance of non-standard warm mix asphalt. Similarly, no previous studies have compared data on quality assurance/quality control (QA/QC) and performance for these mixtures with those of standard warm mix asphalt mixtures. Thus, the performance …


Audubon Parkway Slab Lifting At Mp 22.75 — Bridge Approach And Departure Settlement, Tim C. Scully Jr. Jun 2019

Audubon Parkway Slab Lifting At Mp 22.75 — Bridge Approach And Departure Settlement, Tim C. Scully Jr.

Kentucky Transportation Center Research Report

The approach/departure Portland Cement Concrete (PCC) panels on the eastbound and westbound side of Audubon Parkway at MP 22.75 over route KY 2120 began to exhibit settlement and cracking in a few locations, which created an uncomfortable ride for motorists. To address this problem, the Kentucky Transportation Cabinet (KYTC) contracted with MasterDry to repair the PCC panel settlement. MasterDry claims that its two-part polyurethane material expands into a rigid foam that fills voids, stabilizes slabs, and lifts concrete. The polyurethane material is injected through 5/8-inch holes drilled in the PCC panel. Once injected, a chemical reaction converts the liquid urethane …


Training Curricula For The Kentucky Transportation Cabinet Department Of Highways, Nancy Albright, Bryan Gibson, Chris Van Dyke, Jeff Jasper, Doug Kreis Jun 2019

Training Curricula For The Kentucky Transportation Cabinet Department Of Highways, Nancy Albright, Bryan Gibson, Chris Van Dyke, Jeff Jasper, Doug Kreis

Kentucky Transportation Center Research Report

Most state departments of transportation (DOTs) offer their employees professional development opportunities (e.g., training courses) so they can build their expertise and in doing so facilitate agency efforts to fulfill their business mandates. The Kentucky Transportation Cabinet (KYTC) is no different in this regard. While professional development opportunities are invaluable, and while the Cabinet offers a number of trainings to its staff, currently there exists no comprehensive training curricula to help professionals and paraprofessionals systematically grow their knowledge and skills and ensure KYTC maintains a robust portfolio of technical competencies across the organization. The inconsistent and ad hoc manner in …


Bridge Load Testing Versus Bridge Load Rating, Abheetha Peiris, Issam E. Harik Jun 2019

Bridge Load Testing Versus Bridge Load Rating, Abheetha Peiris, Issam E. Harik

Kentucky Transportation Center Research Report

The current method of load rating bridges according to AASHTO specifications can underestimate the capacity and behavior of bridges. Analytical equations do not account for the degree of rigidity of the supports, unintended composite action due to friction between girders and the slab, and other factors. Load testing of individual bridges can produce a load rating that much more accurately reflects the capacity of a non-composite bridge. However, current methods of load testing require significant time commitments to instrument a bridge profile to record data, rendering it impractical in many cases. But there are new commercially available strain gauges that …


Redefining Construction As-Built Plans To Meet Current Kentucky Transportation Cabinet Needs, Victoria Lynn Lasley, Steven Waddle, Tim Taylor, Roy E. Sturgill Jr. Jun 2019

Redefining Construction As-Built Plans To Meet Current Kentucky Transportation Cabinet Needs, Victoria Lynn Lasley, Steven Waddle, Tim Taylor, Roy E. Sturgill Jr.

Kentucky Transportation Center Research Report

As-built plans have traditionally been used by construction industry practitioners to record changes made during construction. As-builts provide valuable information for new design projects as well as rehabilitation and remediation projects. The completeness and accuracy of these plans are essential for transportation industries and their success. While the importance of as-builts is widely recognized, preparing them can be difficult and time-consuming; many entities — especially public agencies — lack the resources necessary to produce accurate and detailed as-builts. After investigating the current as-built operations of state transportation agencies, Kentucky Transportation Center (KTC) researchers devised recommendations to improve the Kentucky Transportation …


Reducing Construction Costs Through Effective Field Communication And Administration, Gabriel B. Dadi, Roy E. Sturgill Jr., Steven Waddle, Steven Douglas Kreis Jun 2019

Reducing Construction Costs Through Effective Field Communication And Administration, Gabriel B. Dadi, Roy E. Sturgill Jr., Steven Waddle, Steven Douglas Kreis

Kentucky Transportation Center Research Report

Falling Road Fund receipts have placed added strain on the Kentucky Transportation Cabinet’s (KYTC) already-underfunded highway program. Revenue declines have increased the urgency of improving the efficiency and cost-effectiveness of the Cabinet’s operations. One method KYTC can use to realize greater cost savings is improving the administration of construction projects. Effective field communication and administration helps control construction costs, enhances quality, and minimizes delays and claims. One challenge the Cabinet will need to confront to more effectively administer projects, however, is the loss of institutional knowledge associated with staff attrition. The report documents KYTC current methods for project staffing, communication, …


Do Transportation Network Companies Decrease Or Increase Congestion?, Gregory D. Erhardt, Sneha Roy, Drew Cooper, Bhargava Sana, Mei Chen, Joe Castiglione May 2019

Do Transportation Network Companies Decrease Or Increase Congestion?, Gregory D. Erhardt, Sneha Roy, Drew Cooper, Bhargava Sana, Mei Chen, Joe Castiglione

Civil Engineering Faculty Publications

This research examines whether transportation network companies (TNCs), such as Uber and Lyft, live up to their stated vision of reducing congestion in major cities. Existing research has produced conflicting results and has been hampered by a lack of data. Using data scraped from the application programming interfaces of two TNCs, combined with observed travel time data, we find that contrary to their vision, TNCs are the biggest contributor to growing traffic congestion in San Francisco. Between 2010 and 2016, weekday vehicle hours of delay increased by 62% compared to 22% in a counterfactual 2016 scenario without TNCs. The findings …


Developing Material Specification And Application Criteria For Sealing Concrete Bridge Decks, Danny Wells, Sudhir Palle, Theodore Hopwood Ii May 2019

Developing Material Specification And Application Criteria For Sealing Concrete Bridge Decks, Danny Wells, Sudhir Palle, Theodore Hopwood Ii

Kentucky Transportation Center Research Report

The Kentucky Transportation Cabinet (KYTC) has more aggressively pursued preventive maintenance in recent years. Sealing concrete bridge decks is one preventive maintenance activity the Cabinet has actively pursued. KYTC’s Divisions of Maintenance and Structural Design requested assistance from researchers at the Kentucky Transportation Center (KTC) in developing a material specification and application criteria for sealing concrete bridge decks at an appropriate time in their life cycle.

To develop a material specification and application criteria for sealing concrete bridge decks, KTC researchers conducted the following work:

  1. Perform a national survey of departments of transportation (DOTs) for guidelines.
  2. Perform a literature search …


Using A Balloon-Launched Unmanned Glider To Validate Real-Time Wrf Modeling, Travis J. Schuyler, S. M. Iman Gohari, Gary Pundsack, Donald Berchoff, Marcelo I. Guzman Apr 2019

Using A Balloon-Launched Unmanned Glider To Validate Real-Time Wrf Modeling, Travis J. Schuyler, S. M. Iman Gohari, Gary Pundsack, Donald Berchoff, Marcelo I. Guzman

Chemistry Faculty Publications

The use of small unmanned aerial systems (sUAS) for meteorological measurements has expanded significantly in recent years. SUAS are efficient platforms for collecting data with high resolution in both space and time, providing opportunities for enhanced atmospheric sampling. Furthermore, advances in mesoscale weather research and forecasting (WRF) modeling and graphical processing unit (GPU) computing have enabled high resolution weather modeling. In this manuscript, a balloon-launched unmanned glider, complete with a suite of sensors to measure atmospheric temperature, pressure, and relative humidity, is deployed for validation of real-time weather models. This work demonstrates the usefulness of sUAS for validating and improving …


Modern Roundabouts: A Challenge Of The Future, Tomaž Tollazzi, Raffaele Mauro, Daiva Žilionienė, Irena I. Otković, Nikiforos Stamatiadis Apr 2019

Modern Roundabouts: A Challenge Of The Future, Tomaž Tollazzi, Raffaele Mauro, Daiva Žilionienė, Irena I. Otković, Nikiforos Stamatiadis

Civil Engineering Faculty Publications

No abstract provided.


Determination Of Constructed Pavement Layer Thicknesses Using Nondestructive Testing (Ndt), Brad W. Rister, Jamie Creech, Kean H. Ashurst Jr. Apr 2019

Determination Of Constructed Pavement Layer Thicknesses Using Nondestructive Testing (Ndt), Brad W. Rister, Jamie Creech, Kean H. Ashurst Jr.

Kentucky Transportation Center Research Report

Using nondestructive testing (NDT) to measure the thickness of pavement layers can improve the overall life of a new concrete and/or asphalt pavement. Conventional test methods require the extraction of a core from the pavement section to verify its thickness. Currently, two NDT technologies are commercially available which eliminate or reduce the need to core the existing pavement for thickness verification. The MIT-Scan-T2 (T2) utilizes magnetic pulse induction coupled with preset metal plates to obtain a thickness value. Measurements can be obtained quickly to an accuracy of +/– 2 mm. Ground Penetrating Radar (GPR) uses electromagnetic radiation to determine pavement …


The Effects Of Reactant Concentration And Air Flow Rate In The Consumption Of Dissolved O2 During The Photochemistry Of Aqueous Pyruvic Acid, Alexis J. Eugene, Marcelo I. Guzman Mar 2019

The Effects Of Reactant Concentration And Air Flow Rate In The Consumption Of Dissolved O2 During The Photochemistry Of Aqueous Pyruvic Acid, Alexis J. Eugene, Marcelo I. Guzman

Chemistry Faculty Publications

The sunlight photochemistry of the organic chromophore pyruvic acid (PA) in water generates ketyl and acetyl radicals that contribute to the production and processing of atmospheric aerosols. The photochemical mechanism is highly sensitive to dissolved oxygen content, [O2(aq)], among other environmental conditions. Thus, herein we investigate the photolysis (λ ≥ 305 nm) of 10–200 mM PA at pH 1.0 in water covering the relevant range 0 ≤ [O2(aq)] ≤ 1.3 mM. The rapid consumption of dissolved oxygen by the intermediate photolytic radicals is monitored in real time with a dissolved oxygen electrode. …