Noise barriers along high-volume roads reduce traffic noise using either normal-weight materials, such as concrete or brick, or lightweight materials, such as metal, composites, fiberglass, or acrylic. Although the Virginia Department of Transportation’s (VDOT) current concrete noise barriers have proven durable, some lightweight metal noise barrie
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Comparing studies that involve techno-economic analyses (TEA) and life cycle assessments (LCA) for different hydrogen production technologies is challenging due to inconsistent assumptions across studies. Thus, this research develops a harmonized framework to assess seven hydrogen production pathways - water electrolysis, methane pyrolysis, biomass
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Determining the size of soot particles in dynamic turbulent flames is critical for optimizing injector and combustor designs. In this work, we demonstrate the first use of a gigahertz-rate framing camera for planar time-resolved laser-induced incandescence (TiRe-LII) measurements in a rich quench lean (RQL) combustion system with Jet A fuel. In thi
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Open-graded granular backfill materials are widely used as retaining wall backfill due to their high shear strength, high permeability, ease to handle, and compaction characteristics. However, the current Tennessee Department of Transportation (TDOT) provisions assume a conservative angle of internal friction for backfill materials. The objective o
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This work leverages an unsupervised machine learning and advanced image processing techniques to characterize the breakup of fuel sprays in a small-scale combustor under reacting conditions, providing valuable insights into near-nozzle flow phenomenology. The proposed methodology integrates an improved optical flow model on a convolutional neural n
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The Aviation Infectious Risk and Safety (AIRS) program addresses the U.S. Government Accountability Office (GAO) recommendation for stronger federal leadership and coordination on communicable disease transmission in air travel. Led by the Federal Aviation Administration (FAA), AIRS integrated The Boeing Company, the Centers for Disease Control and
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Transitioning to alternative energy carriers is one of the primary options for reducing greenhouse gas emissions attributable to transportation. In the US, ethanol from corn grain covers 10.5% of gasoline demand from road transport today. Its production could be scaled-up further to also make sustainable aviation fuel. Additionally, the biogenic CO
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Nighttime environmental noise (EN) exposure disturbs sleep and increases morbidity and mortality. Affordable and effective countermeasures are needed, but rigorous research is scarce. This study investigates the efficacy of pink noise (PN) and earplugs for mitigating the effects of intermittent EN on sleep.
Emissions from land use changes are relevant for environmental policy analysis. Since the late 1990s and early 2000s many of these analyses have examined induced land use changes (ILUC) from biofuel production and policy as well as their associated greenhouse gas (GHG) emissions. These studies have often used the Harmonized World Soil Data (HWSD) t
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This study examines the impact of soil erosion on corn (Zea mays L.) yield across counties in the US Midwest. Using a novel county-level panel dataset that includes information on water erosion and corn yield, we analyze the direct and spatial spillover effects of erosion using a spatial regression framework. We find that increases in soil erosion
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Truck traffic is an important input for pavement design and analysis. Proper characterization of traffic patterns contributes to the design of reliable and cost-effective pavement structures. Axle load spectra obtained from the Long-Term Pavement Performance (LTPP) database, together with local Annual Average Daily Traffic (AADT) data from Tennesse
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Replacing conventional aviation fuel (CAF) with sustainable aviation fuel (SAF) has been suggested as a vital means to decarbonize the aviation industry. We considered winter canola a feedstock for SAF production through the hydro-processed esters and fatty acids pathway in the Southeast United States. We incorporated feedstock yield variations in
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The environmental impact of nitrogen oxide (NOx) emissions varies with emission altitude and latitude. NOx emissions from subsonic aviation (9-12 km) contribute to net global ozone formation, whereas those from supersonic aircraft (above 14 km) lead to net global ozone depletion. However, the effects of NOx emission altitude on surface air quality
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Policymakers and the aviation industry are working to decarbonize commercial flights by replacing conventional jet fuel with sustainable aviation fuel (SAF). Logging residues have been identified as a valuable resource for SAF production. However, the quality of the feedstock, particularly the ash content, can adversely affect bio-oil yield and SAF
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A broad range of AAM aircraft are currently in development, each with varying community noise footprints and energy consumption depending on the specifics of their departure and arrival flight trajectories, which must be understood for effective airspace integration. This work presents a framework for analyzing AAM trajectory design, focusing on ke
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The goal of this project is to add corresponding cryogenic hydrogen infrastructure analysis to a previous study conducted at NREL. Sponsored by the FAA, NREL's study investigated hydrogen implementation at the Seattle, Portland, San Francisco, and Los Angeles airports, primarily focusing on gaseous hydrogen delivery and conducting technoeconomic, e
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Sustainable aviation fuel (SAF) production is essential for decarbonizing the aviation sector in the short and midterm as well as maintaining the global competitiveness of U.S. airlines, supporting job creation, and ensuring U.S. energy independence. The near-term U.S. SAF target, set by the SAF Grand Challenge, is 11.4 billion liters (3 billion ga
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Sustainable aviation fuels (SAF) can reduce aviation greenhouse gas emissions, yet their production scale-up to meet policy goals remains unexplored. Here, we describe the Global SAF Capacity Database to quantify global and European Union (EU) SAF capacity, comparing it to production capacity announcements. Despite announcements of 9.1 Mt year−1 (2
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Contrails are a significant contributor to aviation's climate impact with an effective radiative forcing similar to that from aviation's CO2 emissions, yet large uncertainties remain. Many observational contrail studies rely on data from a single sensor, in recent years increasingly from a geostationary imager, accepting lower spatial resolution in
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Work zones (WZs) are among the most hazardous roadway environments due to restricted geometry, temporary traffic control, and increased driver workload, which often lead to speeding and elevated crash frequency as well as severity. A section of roadway of nearly 8 miles long on I-65, in Robertson County, near the Kentucky state border, where additi
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