Engineering Commons^™

Replication Data For: Investigating Detection Probability Of Mobile Survey Solutions For Natural Gas Pipeline Leaks Under Different Atmospheric Conditions, Shanru Tian, Stuart Riddick, Younki Cho, Bell Clay, Daniel Zimmerle, Kathleen Smits

Earth & Environmental Sciences Datasets

The 2015 Paris agreement aims to cut greenhouse gas emissions and keep global temperature rise below 2 °C above pre-industrial levels. Reducing CH4 emissions from leaking pipelines presents a relatively achievable objective. While walking and driving surveys are commonly used to detect leaks, the detection probability (DP) is poorly characterized. This study aims to investigate how leak rates, survey distance and speed, and atmospheric conditions affect the DP in controlled belowground conditions with release rates of 0.5–8.5 g min−1. Results show that DP is highly influenced by survey speed, atmospheric stability, and wind speed. The average DP in Pasquill–Gifford stability …

Replication Data For: A Closer Look At Underground Natural Gas Pipeline Leaks Across The United States, Younki Cho, Kathleen M. Smits, Nathaniel L. Steadman, Bridget A. Ulrich, Clay S. Bell, Daniel J. Zimmerle

Earth & Environmental Sciences Datasets

Underground natural gas (NG) pipeline leakage can result in methane (CH₄) buildup and migration through the soil. What is not well understood in such scenarios is how the soil conditions affect the gas migration behavior, particularly in regard to the relative contributions of specific soil properties such as soil moisture content. The objective of this study was to investigate the effects of soil properties on CH₄ concentration and migration from leaking underground NG pipelines. Site characteristics such as surface cover and spatial dimensions, soil samples, and gas concentration data were collected from over 70 gas leakage sites …

Hydrodynamic Limitations To Mangrove Seedling Retention In Subtropical Estuaries, Kelly M. Kibler, Christian Pilato, Linda Walters, Melinda Donnelly, Jyotismita Taye

Flow-biota Interaction and Natural Infrastructure Design

Mangrove forest sustainability hinges upon propagule recruitment and seedling retention. This study evaluates biophysical limitations to mangrove seedling persistence by measuring anchoring force of two mangrove species (Rhizophora mangle and Avicennia germinans). Anchoring force was measured in 362 seedlings via lateral pull-tests administered in mangrove forests of two subtropical estuaries and in laboratory-based experiments. Removal mechanism varied with seedling age: newly-established seedlings failed due to root pull-out while seedlings older than 3 months failed by root breakage. Anchoring force of R. mangle seedlings was consistently and significantly greater than A. germinans (GLM: p = 0.002), however force to …

Replication Data For "Estimating Methane Emissions From Underground Natural Gas Pipelines Using An Atmospheric Dispersion-Based Method", Shanru Tian, Kathleen M. Smits, Younki Cho, Stuart Riddick, Daniel Zimmerle, Aidan Duggan

Earth & Environmental Sciences Datasets

Methane (CH₄) leakage from natural gas (NG) pipelines poses an environmental, safety, and economic threat to the public. While previous leak detection and quantification studies focus on the aboveground infrastructure, the analysis of underground NG pipeline leak scenarios is scarce. Furthermore, no data from controlled release experiments have been published on the accuracy of methods used to (1) quantify emissions from an area source and (2) use these emissions to quantify the size of a subsurface leak. This proof-of-concept work uses CH₄ mole fraction, as measured by a single gas sensor, as an input to a simple …

Replication Data For: Characterization Of Grain-Size Distribution, Thermal Conductivity, And Gas Diffusivity In Variably Saturated Binary Sand Mixtures, C. T.K.K. Deepagoda, Kathleen Smits

Earth & Environmental Sciences Datasets

Characterization of differently textured porous materials, as well as different volumetric porous media mixtures, in relation to mass and heat transport is vital for many engineering and research applications. Functional relations describing physical (e.g., grain-size distribution, total porosity), thermal, and gas diffusion properties of porous media and mixtures are necessary to optimize the design of porous systems that involve heat and gas transport processes. However, only a limited number of studies provide characterization of soil physical, thermal, and gas diffusion properties and the functional relationships of these properties under varying soil water contents, especially for soil mixtures, complicating optimization efforts. …

Replication Data For: Effect Of Varying Atmospheric Conditions On Methane Boundary-Layer Development In A Free Flow Domain Interfaced With A Porous Media Domain, C. T.K.K. Deepagoda, Kathleen Smits

Earth & Environmental Sciences Datasets

Mitigation of atmospheric emission of methane from leaky underground infrastructure is important for controlling the global anthropogenic greenhouse gas burden. Overexposure to methane may also cause occupational health problems in indoor/outdoor environments at the local scale. Subsurface soil conditions (e.g. soil heterogeneity) affect methane migration in soils while near-surface atmospheric boundary conditions (e.g. wind and temperature) affect off-site emissions across the soil-atmosphere interface. This study investigated the above-surface methane concentration boundary-layer development under different soil conditions (homogenous and layered) and atmospheric boundary controls (wind and temperature). A series of controlled bench-scale experiments was conducted using an open-loop boundary-layer wind tunnel …

Replication Data For: Thermal Conductivity Of Binary Sand Mixtures Evaluated Through Full Water Content Range, Benjamin Wallen, Kathleen Smits

Earth & Environmental Sciences Datasets

A soil's grain-size distribution affects its physical and hydraulic properties; however, little is known about its effect on soil thermal properties. To better understand how grain-size distribution affects soil thermal properties, specifically the effective thermal conductivity, a set of laboratory experiments was performed using binary mixtures of two uniform sands tightly packed with seven different mixing fractions over the full range of saturation. For each binary mixture, the effective thermal conductivity, λ, capillary pressure, hc, and volumetric water content, θ, were measured. Results demonstrated that the λ–θ relationship exhibited distinct characteristics based on the percentage of fine- and coarse-grained sands. …

Replication Data For: Effect Of Subsurface Soil Moisture Variability And Atmospheric Conditions On Methane Gas Migration In Shallow Subsurface, C. T.K.K. Deepagoda, Kathleen Smits

Earth & Environmental Sciences Datasets

A major concern resulting from the increased use and production of natural gas has been how to mitigate fugitive greenhouse gas emissions (predominantly methane) from natural gas infrastructure (e.g., leaky shallow pipelines). Subsurface migration and atmospheric loading of methane from pipeline leakage is controlled by source configurations and subsurface soil conditions (e.g., soil heterogeneity and soil moisture) and are further affected by atmospheric conditions (e.g., wind and temperature). However, the transport and attenuation of methane under varying subsurface and atmospheric conditions are poorly understood, making it difficult to estimate leakage fluxes from methane concentration measurements at and above the soil …

Sweet (Small Wind Energy Estimation Tool), Thomas Woolmington, Keith Sunderland

Other resources

Description:

Generic Wind Energy Estimation Model incorporating Turbulence Intensity.

Requirements:

Manufacturer specific wind turbine characteristic

Mean wind speed at a specific height

Site conditions in terms of TI and Surface Roughness

Disclaimer:

This model has been designed as an estimation tool for estimating the wind power yield of a custom turbine for an idealised set of site conditions for a given year.

While the assumptions that are made in this estimation tool are mathematically plausible they should not in any way be interpreted as an alternative to a real world site assessment.

A list of assumptions to which the model …