Browsing by Subject "Maintenance"
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Item Assessment and Recommendations for the Operation of Standard Sumps as Best Management Practices for Stormwater Treatment (Volume 2)(Minnesota Department of Transportation, 2012-05) McIntire, Kurtis D.; Howard, Adam; Mohseni, Omid; Gulliver, John S.In order to improve the performance of standard sumps as a best management practice (BMP) in treating stormwater runoff, a baffle was designed to be installed as a retrofit in standard sumps. The retrofit is a porous baffle called “SAFL Baffle”. The effect of the SAFL Baffle on the performance of standard sumps was assessed by conducting laboratory tests on small scale as well as full scale straight flow-through standard sumps equipped with the baffle. In addition, a number of tests were conducted to determine the performance of standard sumps with the SAFL Baffle when the baffle is clogged with debris like trash and vegetation. Furthermore, the performance of two other configurations of the baffle was studied: (1) the SAFL Baffle in a sump with an outlet pipe 90 degrees to the inlet pipe, and (2) the SAFL Baffle in a sump with some water entering the sump through an overhead inlet grate. Standard sumps equipped with the SAFL Baffle were evaluated using two metrics: (1) How well the system captures sediment during low flow conditions (Removal Efficiency Testing), and (2) how well the system retains the previously captured sediment during high flow conditions (Washout Testing). The results of the tests showed that the SAFL Baffle dissipates the energy of water entering the sump and as a result, at low flow rates, it captures sediment better than a standard sump with no baffle. More importantly, at high flow rates, the washout of the previously captured sediment reduces to near zero.Item Development of a Mobile App for Reporting Work Zone Intrusions(Minnesota Department of Transportation, 2024-01) Davis, Brian; Morris, Nichole L.; Craig, Curtis; Schumacher, John; Khoday, AnnaikaWork zone intrusions represent a significant safety risk to workers. To help better understand these situations, the Minnesota Department of Transportation partnered with the University of Minnesota to create a method to document intrusion events. This information provides a deeper understanding of the circumstances under which these events occur and enables data-driven decision making when considering ways to reduce or mitigate work zone intrusions. This work focuses on the development of a mobile smartphone app that allows workers to report intrusions from the field immediately after they occur, allowing for timely and accurate intrusion reporting. The work zone intrusion mobile app is developed using an iterative, user-centered design process that solicits feedback from work zone personnel, supervisors, and work zone safety stakeholders at every step in the process. The app uploads completed report data to the existing eSAFE system, allowing for a single repository of collected intrusion report data. To support deployment of the system, training workshops and supporting training and communications materials are created for distribution among users. Throughout the development and deployment of the app, user feedback shows that the app is easy to use and well liked.Item Enhancing maintenance and generalization of incremental rehearsal through theory-based modifications(2013-05) Petersen-Brown, ShawnaThe attainment of basic early literacy skills at an early age is one way to ensure children become proficient readers as adults. Word recognition is an important basic early literacy skill that is related to reading fluency and overall reading competency. Incremental rehearsal (IR) is a flashcard technique that has produced strong outcomes for a variety of outcomes including word recognition. Modifications to IR that are based on theory may enhance maintenance and generalization, outcomes that are frequently overlooked in flashcard intervention research. A number of theoretical frameworks were utilized in this research to enhance maintenance and generalization. The depth of processing framework was used, which suggests that semantic processing of information leads to better maintenance. The theory of common elements and Stokes and Baer's (1977) generalization framework were utilized as frameworks for enhancing generalization. In addition to intervention design, individual factors may also impact intervention efficacy. For example, working memory capacity may influence the amount of verbal information an individual can process. Decoding skill may also lead to enhanced outcomes in word recognition interventions. The current study examined the impact of theory-based modifications to IR on maintenance and generalization. A within-subjects design was utilized in which all participants were taught seven unknown words in each of three IR variants - IR, IR with vocabulary (IR-V, which leveraged the depth of processing framework), and IR with context (IR-C, which leveraged Stokes and Baer's [1977] generalization framework and the theory of common elements). Auditory working memory and decoding skills were also measured as individual factors and potential moderators of intervention effects. Primary dependent variables were maintenance and generalization at 1 and 2 weeks after teaching. Results of the study indicated that maintenance and generalization were high across conditions, suggesting possible ceiling effects. However, 1-week maintenance was significantly greater in IR-V than IR and in IR-C than IR. Additionally, 2-week generalization was significantly greater in IR-V than IR. Effect sizes were small across outcomes in favor of IR-V and IR-C. IR was the most efficient intervention variant in words maintained per minute. A moderating effect of auditory working memory capacity was not observed. However, participants with low decoding skill maintained significantly more words through IR-V than IR at 1 week, while this difference was not observed in participants at higher decoding skill levels. Future research may investigate theory-based modifications applied to different populations (such as students with low decoding skills) or different information types. In addition, future research may investigate theory-based modifications to more efficient modifications of IR (perhaps with fewer opportunities to respond) to enhance the efficiency of these approaches.Item Field And Laboratory Evaluation of Asphalt Crack Sealant Performance(2020-05) Munch, JaredCrack sealing on hot-mix asphalt (HMA) pavement roads is a pavement maintenance technique used to limit the intrusion of water into the pavement structure, and thereby, delay additional distresses. There are two commonly used methods of crack sealing in Minnesota: (i) clean-and-seal, and (ii) rout-and-seal. Since roads in Minnesota are extremely susceptible to cracking in the transverse direction, the goal of this study was to provide insight to the most effective method of crack sealing on asphalt pavements. Based on the field performance results, this study compared the abovementioned two methods for difference scenarios and developed a decision tree to identify the most effective crack sealing method for a given condition of pavement and traffic. As an additional component to the primary study, a new testing procedure for evaluating the adhesiveness between the sealant material and the HMA matrix was developed. This procedure tests sealant materials in tension to produce a stress/strain curve of the sealant as it fails.Item Improving the Safety and Efficiency of Roadway Maintenance Phase I: Developing a Robotic Roadway Message Painter Prototype(Intelligent Transportation Systems Institute, Center for Transportation Studies, University of Minnesota, 2012-05) Rosandich, Ryan G.A large-scale prototype for a robotic roadway message painter was developed, built, and tested. The system is a gantry-style robot capable of painting a four-by-eight-foot area and is based on off-the-shelf linear motion components, readily available motion control hardware, and commercial operator interface software. The system is mounted on a modified trailer that can be manually rolled around for positioning or towed behind a vehicle. The system is equipped with a standard automatic paint head and airless paint pump. Software was developed for the system that enables it to paint a variety of characters and symbols on the roadway. An operator interface was also developed that allows an operator to easily select the painting operation to be conducted and to monitor and control the actual painting process. The software resides in a laptop computer that communicates with the robotic painting system in real-time using a dedicated Ethernet connection. The system was used to determine the feasibility of painting with or without stencils and to determine many design parameters for the eventual development of a commercially viable system for painting symbols and messages on roadways. It is expected that the system will eventually enable states, counties, and municipalities to improve the safety, productivity, and flexibility of their pavement marking operations.Item Improving the Safety and Efficiency of Roadway Maintenance Phase II: Developing a Vision Guidance System for the Robotic Roadway Message Painter(Intelligent Transportation Systems Institute, Center for Transportation Studies, University of Minnesota, 2013-02) Rosandich, Ryan G.Repainting existing roadway markings (turn arrows, STOP messages, railroad crossings, etc.) is an important task for transportation maintenance organizations. MnDOT estimates that over 75% of symbol and message painting is the repainting of existing markings. It would be extremely valuable for an automated painting system to have a vision guidance capability whereby an existing mark could be repainted accurately with little operator input. In this project a vision system was developed that is capable of identifying existing painted pavement markings and determining their dimensions, location, and orientation. Techniques were also developed whereby this information could be used to determine the location of the marking in the workspace of a painting robot to enable it to accurately repaint the marking. The vehicle-mounted robotic painter is still being built and tested, so final test results will not be available until the vision system can be completely integrated with the painter, and the two can be tested together. The accuracy of the projection produced using the techniques developed in this project would suggest that the final system will be capable of repainting pavement markings almost exactly where they appear on the roadway. Expected benefits of the deployment of a vision-guided robotic painting device include improved operator safety, improved productivity, and improved flexibility in roadway marking and repainting operations. Eventual users of a device using this technology could be city, county, state, and federal government agencies and private companies or contractors.Item Iron-Enhanced Swale Ditch Checks for Phosphorus Retention(Minnesota Department of Transportation, 2019-07) Natarajan, Poornima; Gulliver, John S; Weiss, Peter TIron-enhanced ditch checks in roadside swales were developed specifically for capturing dissolved phosphorus and dissolved metals from roadway runoff in both urban and agricultural environments. One iron-enhanced ditch check constructed along CR 15 (formerly TH 5) in Stillwater, Minnesota, was monitored during 40 storm events from 2016 to 2018. The iron-enhanced sand filter insert generally captured phosphate, yielding lower phosphate concentrations and mass load reductions that varied between 22% and 50% during several events. However, the cumulative phosphate retention in the filter insert decreased from 42% in 2015 to 30% in 2016, 25% in 2017, and 23% in 2018. The filter insert was not an effective retention device for dissolved copper and zinc. The overall ditch check’s performance, although unexceptional in 2016 and 2017, appeared to improve in 2018. Sampling issues likely contributed to the low performance measured until 2017. The 2018 water sample collection method provided a better estimate of the ditch check’s performance and roughly matched that of the filter insert. Synthetic runoff testing supported the level of treatment achieved during storm events. Phosphate load from the degrading topsoil and the overutilization of the bottom filter media most likely affected overall treatment performance. Design improvements and recommended maintenance actions were developed based on the lessons learned from field monitoring. The iron-enhanced ditch check can improve net phosphate retention through roadside swales, as long as the recommended maintenance actions are performed as scheduled.Item Permeable Pavements in Cold Climates: State of the Art and Cold Climate Case Studies(Center for Transportation Studies, University of Minnesota, 2015-06) Weiss, Peter T.; Kayhanian, Masoud; Khazanovich, Lev; Gulliver, John S.This document is an extensive review of full-depth permeable pavements including porous asphalt, pervious concrete, and permeable interlocking concrete pavers (PICP). Also included is a brief section on articulated concrete blocks/mats. The main topics, which have been divided into chapters, include structural and mix design, hydrologic design, hydraulic performance (i.e. infiltration capacity), maintenance needs/frequency/actions, the impact of permeable pavement on water quality, results of a highway shoulder feasibility study, knowledge gaps, and several cold climate case studies from the United States and Canada. While progress has recently been made with the relatively new permeable pavement technology, researchers have also identified many unresolved issues that are not well understood. These include a methodology to measure subgrade infiltration rates, filling data gaps related to structural integrity, construction, and related issues associated with permeable pavements, determining what maintenance activities are most effective on various pavement types and how frequently specific maintenance actions should be performed, a better understanding of the processes involved in the observed reduction of contaminant concentrations in stormwater flowing through permeable pavements, and a better understanding of the performance of permeable pavements over a time frame that better corresponds with a life-span of 20 years.Item Quality of Life: Assessment for Transportation Performance Measures(Minnesota Department of Transportation, 2013-01) Schneider, Ingrid E.; Guo, Tian; Schroeder, SierraQuality of life (QOL) is a commonly used term. Defining QOL, however, is an ongoing challenge that experts often take on with minimal input from citizens. This groundbreaking research sought citizen input on what comprised QOL and what role transportation played in it. Further, this research explored in detail the important factors across the breadth of transportation and how the Minnesota Department of Transportation (MnDOT) was performing on these important factors. The research encompassed three phases between 2010 and 2011: (1) an extensive literature review on QOL, (2) 24 focus groups that asked Minnesota’s citizens about their QOL, and (3) a mail questionnaire about what matters in quality of life, transportation and their intersection. Eleven related quality of life factors emerged, including transportation: education, employment and finances, environment, housing, family, friends and neighbors, health, local amenities, recreation and entertainment, safety, spirituality/faith/serenity, and transportation. Within transportation, seven important areas were identified that predicted satisfaction with MnDOT services: access, design, environmental issues, maintenance, mobility, safety and transparency. Results reveal that a) QOL is complex and transportation plays an important and consistent role in it across Minnesota; b) transportation is critical to QOL because it connects us to important destinations in aspects that matter most; and c) Minnesotans can readily identify what matters and how the state is performing within the breadth of transportation services.Item Review of the Applications of Microwave Heating for Asphalt Pavement Maintenance(2021-06) Calhoon, ThomasThe propagation of microcracks into more serious pavement distresses is a major concern for asphalt pavements. Much work has been done to accelerate and control the asphalt self-healing of microcracks through the application of external heating methods including microwave heating. This thesis provides a state of the art of application of microwave heating of asphalt pavements, including self-healing. The principles of microwave heating, components of a microwave system, and different types of microwave systems are discussed. Then, an extensive literature review on the use of microwaves on asphalt pavements is presented. The review covers several applications of microwave heating on asphalt pavements and additives that enhance the microwave-absorbing capabilities of asphalt materials. Then, the results of a laboratory fatigue-heal cycle experiment are presented. The results demonstrate the ability of microwave heating to activate asphalt self-healing. Then, a 1D microwave heat transfer model is presented. A sensitivity analysis is performed on several model parameters. The analysis reveals that some parameters, such as thermal conductivity, do not significantly impact the microwave heating outcome, while some, such as applied microwave power density, do. Finally, recommendations are made for future work including field trials of discussed applications and implementation of the presented model in a computer application.Item Stormwater BMP Inspection and Maintenance Resource Guide(Minnesota Department of Transportation, 2024-06) Erickson, Andrew J.; Gulliver, John S.; Weiss, Peter T.Stormwater treatment practices, often referred to as stormwater best management practices (BMPs), require a substantial commitment to maintenance, including regular inspections and assessments. Existing regulations require governmental units to develop a systematic approach for ongoing inspection and maintenance to ensure that they are achieving their desired treatment goals. A lack of maintenance will lead to a decrease in BMP performance and will often result in expensive rehabilitation or rebuild. In 2009, SRF Consulting produced a maintenance guide for the Local Road Research Board (LRRB) (Marti, et al. 2009). In 2023, the LRRB commissioned the University of Minnesota St. Anthony Falls Laboratory to update this guide to reflect new best practices. The Stormwater BMP Inspection and Maintenance Resource Guide (the Guide) is a supplement to the Minnesota Stormwater Manual (MPCA 2023) and will help the reader plan for recommended long-term maintenance activities through guidance on visual inspection, testing, and monitoring methods for identifying what maintenance is needed, and when it is needed. The Guide describes inspection and maintenance for constructed stormwater ponds (both dry and wet) and wetlands, underground sedimentation practices, infiltration practices, filtration practices, bioretention practices, permeable pavements, and stormwater harvesting. In addition, the Guide includes a section on Meeting Stormwater Management Objectives, which provides information on achieving reductions for sediment, phosphorus, nitrogen, metals, chloride, pathogens, and organic chemicals. The Guide also includes Field Inspections Resources, which contains inspection checklists and maintenance activity recommendations for all of the practices listed above.Item Stormwater Pond Maintenance, and Wetland Management for Phosphorous Retention(Minnesota Department of Transportation, 2023-06) Janke, Benjamin D.; Natarajan, Poornima; Gulliver, John S.; Finlay, Jacques C.Reduction in phosphorus is critical because phosphate, a dissolved form of phosphorus, sustains algal and cyanobacteria growth and causes a wide range of water-quality impairments in the ponds and downstream waters including algal blooms, excess floating plants, taste, and odor problems. Many stormwater ponds and wetlands that treat stormwater appear to be less effective than expected or originally intended in phosphorus retention, a key function of these ponds in urban environments. There is evidence that many old ponds are releasing phosphorus from bottom sediments at high rates and likely exporting phosphorus to downstream surface water bodies. A major outcome of this project is a pond Assessment Tool to assess the risk of high phosphorus concentrations in ponds and sediment release of phosphorus. The tool is based on 20 ponds with detailed water quality and phosphorus release measurements and a meta-analysis of 230 ponds in the Twin Cities metro area. Other outcomes included a working definition of a constructed stormwater pond and a wetland treating stormwater in the framework of water-body regulations, the development of recommendations for stormwater pond maintenance and wetland management, and an update to the sections on the constructed stormwater ponds section of the 2009 Stormwater Maintenance BMP Guide.Item UAV Laboratories Processes and Procedures(2014-07-23) Taylor, BrianItem User-centered Smart Traffic Sign Development Study(Minnesota Department of Transportation, 2023-06) Morris, Nichole L.; Rajamani, Rajesh; Drahos, Bradley A.; Xie, Zhenming; Alexander, Lee; Kessler, WilliamFlaggers protect workers by providing temporary traffic control and maintaining traffic flow through a work zone. They are often the first line of defense to stop distracted, inattentive, or aggressive motorists from intruding into the work area. This project aims to develop an automated intrusion detection system to alert drivers who are unsafely approaching or entering a flagger-controlled work zone. A human factors user needs assessment found maintenance workers preferred a modified traffic signal to feature the alert system due to flagger risks of being in the roadway and drivers failing to stop and remain stopped when presented with the STOP side of the flagger sign. A modified traffic signal that could be operated using a handheld remote was developed. The low-cost embedded electronics on the traffic signal enabled it to track trajectories of nearby vehicles, detect potential intrusions, and trigger audio-visual warnings to alert the intruding driver. Usability testing in a simulated driving test found poor expectancies and stopping rates of the traffic signal-based alarm system compared to a traditional flagger but did demonstrate evidence that drivers may be less likely to stop and remain stopped with the flagger STOP sign than the red ball indicator of the traffic signal. Furthermore, some drivers corrected their initial stopping error after triggering the auditory alarm of the traffic signal. A follow up test found improved performance with the alert system incorporated into an audiovisual enhanced STOP/SLOW flagger paddle. Testing of the developed sensor system found the system capable of simultaneous multivehicle tracking (including estimation of vehicle position, velocity, and heading) with a range of up to 60 meters and angular azimuth range of 120 degrees and correctly detecting all test intruding vehicles.Item Wet Pond Maintenance for Phosphorus Retention(Minnesota Department of Transportation, 2022-06) Taguchi, Vinicius J.; Janke, Benjamin D.; Herb, William R.; Gulliver, John S.; Finlay, Jacques C.; Natarajan, PoornimaThis report considers the outcomes of the pond maintenance strategies of sediment treatment to reduce internal loading of phosphorus, mechanical aeration, alteration of pond outlet to pull water off the bottom, reduction of wind sheltering, dredging, outlet treatment by iron enhanced sand filtration and reduction of phosphorus loading from the watershed. The strategies were analyzed with the model CE-QUAL-2E, where inputs to the model were initial conditions, morphology, inflow rate and total phosphorus and soluble reactive phosphorus concentrations, sediment oxygen demand, sediment release of phosphate, and meteorological conditions. The model as applied in this research simulates stratification, wind mixing, outflow and vertical profiles of temperature, dissolved oxygen, chloride, soluble reactive phosphorus, and total phosphorus. The model is calibrated on data from Alameda pond, verified on data from the Shoreview Commons pond, and applied to maintenance and remediation strategies for the Alameda, Shoreview Commons, Langton, and Minnetonka 849W ponds. Costs of maintenance or remediation strategies are estimated and the cost per reduction in total phosphorus release is calculated.Item What sustains behavioral changes? A dynamical systems approach to improving theories of change in physical exercise(2019-08) Lenne, RichardHealth behaviors, such as physical exercise, are associated with chronic diseases that top the list of all-cause mortality. Yet, the most healthful lifestyle changes people can (and often want to) make, also tend to be the most challenging to sustain. This dissertation explores how modeling behavior as a dynamical system could improve understanding of psychological processes that sustain behavioral changes. I focus on two classes of processes—motivational and habitual—that may be most pertinent to sustaining changes in physical exercise. A model based on prior theorizing is constructed and simulated (Study 1), and observational data are analyzed (Study 2). Intensive longitudinal data are collected from healthy US-based Fitbit users who recently initiated an increase in exercise. Participants are prospectively observed for two months during which measures of motivation and habit are assessed three days per week, and exercise-as-usual is passively tracked via Fitbit. I find that within-person increases in the automaticity with which exercise is performed in a given week is associated with increases in time spent exercising. Furthermore, differences in the trajectory of automaticity and satisfaction with exercise over time may differentiate those who successfully maintain increases in exercise and those who do not. Results are placed in the context of contemporary theories of behavior change maintenance and suggestions for improvement are forwarded.