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The Role of the Owner’s Representative in Public Projects
Get PDFThis presentation will explain how an owner’s representative works with the municipality to deliver quality projects on behalf of the community
MSE Walls Retrofit Design and Construction
Get PDFPresenters will share the INDOT MSE wall retrofit contracting approach, design, and construction for existing MSE walls that showed signs of significant premature distresses
Exit 10 Renovations
Get PDFBuilt in 1956, the infrastructure at Exit 10 of the Indiana Toll Road (ITR) needed multiple repairs, including bridge rehabilitation, pavement restoration, and lighting improvements. ITRCC invested in cost-effective renovations on 12 bridges in the Exit 10 vicinity that that would reduce long-term maintenance. The project experienced challenges due to the complexity of construction and mainline work occurring simultaneously to accelerate construction. This presentation will focus on the design approach, contractor procurement, and construction of this investment
Concrete Pavement Basics 101
Get PDFDo we need to seal joints? Why is water to cement ratio important? How do we handle utility cuts and patches? Significant advancements in concrete pavement materials and processes have evolved during the past decade; however, fundamental practices in concrete pavement construction remain more important than ever if we want to achieve the desired service life and value for the taxpayer. This session takes us “back to the basics” with appropriate updates on what’s change and what hasn’t changed in concrete materials and construction
Effect of Black Soldier Fly Larvae and Food Substrates on Weed Seed Emergence
Get PDFBlack soldier fly larvae (Hermetia illucens; BSFL) composting is biotechnology used for organic waste management and an alternative to traditional composting. We designed a two-phase experiment to evaluate the effect of BSFL composting on the emergence of the following six weed species: barnyardgrass (Echinochloa crus-galli), common ragweed (Ambrosia artemisiifolia), giant foxtail (Setaria faberi), ivyleaf morningglory (Ipomoea hederacea), redroot pigweed (Amaranthus retroflexus), and velvetleaf (Abutilon theophrasti). The first experiment phase was in the laboratory (laboratory composting phase), which consisted of 100 seeds of each weed species subjected to five composting treatments [two controls (nontreated and standard Gainesville diet alone) and three types of substrates (standard Gainesville diet, vegetable waste, food waste) + BSFL]. Live pupa weighed 179 mg with the standard Gainesville diet + BSFL and 205 mg with the food waste diet + BSFL. Dry pupa weighed 68 mg and 70 mg, respectively. The BSFL in the vegetable waste + BSFL treatment did not pupate. During the second experiment phase, the composting treatments were placed in a greenhouse to evaluate weed emergence. Emergence in the nontreated control was 62% for barnyard grass, 38% for common ragweed, 26% for giant foxtail, 66% for ivyleaf morningglory, 3% for redroot pigweed, and 69% for velvetleaf. Compared with the nontreated control, all treatments with BSFL reduced the emergence of each weed species to #1%, except for velvetleaf. This study suggests that BSFL composting may effectively reduce weed seed emergence of many weed species and could be a safe alternative to conventional composting processes to minimize weed pressure in compost. However, efficacy may vary by weed species and may be dependent on seed characteristics, such as an impermeable seedcoat
Experimental investigation of post and vented vapor chamber designs for high heat flux dissipation
No full textTo enhance the dryout heat flux of vapor chambers over a 1 cm × 1 cm area, this study describes the testing of four different vapor chamber design architectures (each having an overall size of 50 mm × 50 mm × 5.5 mm). The designs leverage a combination of internal liquid feeding posts and evaporator vapor venting features to improve the capillary-fed boiling performance. The study provides systematic insight into increasing the dryout limit of a vapor chamber and lowering the thermal resistance by assessing the effect of each geometric feature independently. A jet impingement air cooling test facility is used to measure the total thermal resistance of the package in a representative application, while a liquid cooling test facility is used to measure the thermal resistance of the vapor chamber itself. The results show that a vapor chamber with a combination of machined posts coated with sintered wick and vapor vent features has superior performance over vapor chambers with independent features. It dissipated the highest heat flux of 589 W/cm2 and provided the lowest total package thermal resistance of 0.28 K/W for a 1 cm2 heat input area. The performance improvements are attributed to an improved liquid supply utilizing the porous-wick-coated machined posts and a reduction vapor egress pressure utilizing the vent features above the heater area
“Hopes and Fears”: What Do Writing Center Administrators Think of Merging with or Converting into a Learning Center?
Get PDFThis article shares findings from a survey study (n = 73) focused on writing center administrator (WCA) perceptions of two phenomena we see on many secondary and postsecondary campuses in recent years: writing centers expanding to become learning centers, and writing centers consolidating or merging with other tutoring services on campus. Through analysis of the qualitative, open-ended survey responses, the study revealed that WCAs’ views of these trends are greatly impacted by local conditions and levels of autonomy, as well as WCAs’ beliefs about expertise. Also, consolidation and expansion are seen by WCAs as shifting writing center identity in threatening, unpredictable, or generative ways. Differences in the ways these trends have played out in secondary versus postsecondary writing centers are also discussed. Overall, this study discusses WCAs’ experiences and “hopes and fears” regarding writing center expansion or consolidation, shares a framework of considerations for those facing potential expansion or consolidation, and identifies areas for future research
Fatigue-Resistant Mechanoresponsive Color-Changing Hydrogels for Vision-Based Tactile Robots
Get PDFMechanoresponsive color-changing materials that can reversibly and resiliently change color in response to mechanical deformation are highly desirable for diverse modern technologies in optics, sensors, and robots; however, such materials are rarely achieved. Here, a fatigue-resistant mechanoresponsive color-changing hydrogel (FMCH) is reported that exhibits reversible, resilient, and predictable color changes under mechanical stress. At its undeformed state, the FMCH remains dark under a circular polariscope; upon uniaxial stretching of up to six times its initial length, it gradually shifts its color from black, to gray, yellow, and purple. Unlike traditional mechanoresponsive color-changing materials, FMCH maintains its performance across various strain rates for up to 10 000 cycles. Moreover, FMCH demonstrates superior mechanical properties with fracture toughness of 3000 J m−2, stretchability of 6, and fatigue threshold up to 400 J m−2. These exceptional mechanical and optical features are attributed to FMCH\u27s substantial molecular entanglements and desirable hygroscopic salts, which synergistically enhance its mechanical toughness while preserving its color-changing performance. One application of this FMCH as a tactile sensoris then demonstrated for vision-based tactile robots, enabling them to discern material stiffness, object shape, spatial location, and applied pressure by translating stress distribution on the contact surface into discernible images
Electric Vehicles: Public Perceptions, Expectations, and Willingness-to-Pay
Get PDFThe primary objective of this project was to understand Indiana resident’s perspectives on electric vehicles (EVs), including adoption incentives and barriers, awareness of adoption incentives, charging preferences, and general travel patterns. A secondary objective was to establish a framework for identifying EV users, detailing their trips, and generating predictions for EV adoption and usage. To achieve these objectives, a stated preference survey was conducted with 1,217 Indiana residents. Two datasets containing travel behavior data were incorporated to generate synthetic data. The survey results revealed that Indiana EV users are typically middle-aged males living and working in urban areas. EV users tend to drive more frequently than non-EV users and prefer owning EVs over leasing them. They consider home charging as a vital component of EV usage. Non-EV users identified purchase price and charging issues as the main barriers to adoption and are generally unaware of charging incentives. They are also less inclined to use public charging facilities due to their perceived unreliability. EV trips are usually short distance. The generated synthetic dataset aligned with real-world data, predicting future EV demand for the next 8 years. Under an optimistic scenario, the number of EVs could increase by 18 times above the 2023 levels. Under a pessimistic scenario, it could double. This project supports INDOT, and other stakeholders prepare for the increased EV usage resulting from the deployment of charging stations. To foster EV adoption, it is recommended to better promote EV incentives, develop workforce programs focused on used EVs, and provide segmented education about public charging infrastructure
New Repair Strategies for Life-Cycle Extension of Corroded Steel Girder Bridges
Get PDFSteel girder ends are susceptible to corrosion damage due to deicing salts, water, and other contaminants leaking from failed expansion joints. When corrosion becomes significant, it leads to a reduction in the sectional properties of steel girders and consequently reduces bearing and shear resistance. Conventional repair methods, although effective, require substantial time and resources to complete, causing public inconvenience from necessary traffic closures. Therefore, there is a need for practical, rapid, and robust repair methods suitable for implementation by local Department of Transportation (DOT) maintenance personnel. In this study, five innovative repair methods were systematically evaluated through a selection process called the House of Quality Matrix. After completing the comprehensive evaluation and additional numerical simulations, the sandwich panel repair method was selected for further investigation. The sandwich panel repair method encased the corroded region with a filler material reinforced by threaded rods. Two thin steel plates installed on both girder sides served as stay-in-place formwork. This expedited the installation process and eliminated the labor-intensive steps of jacking, welding, and formwork disassembly, thus making the repair more cost-effective and less time-consuming.
The structural performance of the repair method was evaluated experimentally by conducting seven large-scale tests. Various test parameters were considered in the tests, including (1) threaded rod layout, (2) filler material, and (3) support condition. The experimental results indicated that the method was effective in restoring their original design strength. A parametric study complemented the experimental evaluation, using the finite element models benchmarked with experimental results. Design guidelines and recommendations were developed based on the experimental and numerical results