Engineering Commons^™

Delay Causality Network In Air Transport Systems, Wen-Bo Du, Ming-Yuan Zhang, Yu Zhang, Xian-Bin Cao, Jun Zhang

Civil and Environmental Engineering Faculty Publications

To better understand the mechanism of flight delay propagation at the system-level, we built a delay causality network (DCN) based on the Granger causality test. Through topological analysis of DCNs, we found that only about a quarter of airports were involved in delay propagation during the peak travel period and large airports affected by many upstream airports impact fewer downstream airports. Furthermore, temporal analysis of DCNs indicates that the culprits of delay propagation in the air transport system are not a fixed set of airports; instead, they vary daily depending on the operational environment.

Sociodemographics And Access To Organic And Local Food: A Case Study Of New Orleans, Louisiana, Chuo Li, Amir Ghiasi, Xiaopeng Li, Guangqing Chi

Civil and Environmental Engineering Faculty Publications

This study examined the association between physical accessibility to organic and local food, and sociodemographic factors in New Orleans, Louisiana. Spatial regression models were used to investigate how sociodemographic variables such as income, race/ethnicity, education, and age correlate with driving, bicycling, and walking distances to stores that sell organic or local food. The distances were calculated from GIS and real-time speed information from Google Maps. The results indicated that physical access to such stores is positively associated with population density, median housing value, education, non-Hispanic Blacks, and Hispanics, and is negatively associated with median housing age. We found no disparities …

Material Transport Under A Wave Train In Interaction With Constant Wind: A Eulerian Rans Approach Combined With A Lagrangian Particle Dispersion Model, Nityanand Sinha, Roozbeh Golshan

Civil and Environmental Engineering Faculty Publications

The interaction of a developed train of gravity deep water waves with suddenly applied winds is investigated in this manuscript. The direction of the wind is the same as that of the wave train (i.e., following) and its imposed surface shear stress is constant and steady. The focus of this study is on a micro-scale water wave field where the time scale is on the order of ten wave periods and the length scale is on the order of ten wave lengths. Accurate 2D Reynolds-averaged Navier–Stokes (RANS) multi-phase simulations of Navier–Stokes equations are performed in a Eulerian framework to capture …

Future Hydrological Alterations In The Mekong Delta Under The Impact Of Water Resources Development, Land Subsidence And Sea Level Rise, Thanh Duc Dang, Thomas A. Cochrane, Mauricio E. Arias, Van Pham Dang Tri

Civil and Environmental Engineering Faculty Publications

Study Region: The Mekong floodplains and delta are among the most agriculturally productive and biologically diverse waterscapes of the world, but sea level rise, land subsidence, and the proposed upstream development of over 126 hydropower dams and extensive delta-based water infrastructure have raised concern due to potential impacts on the hydrology of the region.

Study Focus: This study aims to quantify the effects of water infrastructure development, land subsidence and sea level rise on hydrological regimes of the Mekong floodplains and delta through the development and application of a hydrodynamic model.

New Hydrological Insights for the Region: Depending on hydrological …

A Systems Analysis Of Factors Influencing Household Solar Pv Adoption In Santiago, Chile, Jeffrey Walters, Jessica Kaminsky, Lawrence Gottschamer

Civil and Environmental Engineering Faculty Publications

Societal uptake of household solar photovoltaic (PV) technology is the result of a complex and interdependent array of technical, social, political and economic factors. This novel study employs a systems lens to examine both technical and non-technical barriers to renewables, with a focus on interactions that are empirically influential on PV uptake. Using local solar expert stakeholder input into a participatory systems approach, this study provides a structural analysis of factors influencing household solar adoption. The approach is applied and assessed for household solar PV systems in Santiago, Chile, to gain insight into the interconnected factors driving technology adoption. Barriers …

Safety Assessment And Risk Estimation For Unmanned Aerial Vehicles Operating In National Airspace System, Xuejun Zhang, Yang Liu, Yu Zhang, Xiangmin Guan, Daniel Delahaye, Li Tang

Civil and Environmental Engineering Faculty Publications

This paper proposes an effective approach for modelling and assessing the risks associated with unmanned aerial vehicles (UAVs) integrated into national airspace system (NAS). Two critical hazards with UAV operations are considered and analyzed, which are ground impacts and midair collisions. Threats to fatalities that result from the two hazards are the focus in the proposed method. In order to realize ground impact assessment, a multifactor risk model is designed by calculating system reliability required to meet a target level of safety for different UAV categories. Both fixed-wing and rotary-wing UAVs are taken into account under a real scenario that …

Oil Droplet Transport Under Non-Breaking Waves: An Eulerian Rans Approach Combined With A Lagrangian Particle Dispersion Model, Roozbeh Golshan, Michel C. Boufadel, Victor A. Rodriguez, Xiaolong Geng, Feng Gao, Thomas King, Brian Robinson, Andres E. Tejada-Martinez

Civil and Environmental Engineering Faculty Publications

Oil droplet transport under a non-breaking deep water wave field is investigated herein using Computational Fluid dynamics (CFD). The Reynolds-averaged Navier–Stokes (RANS) equations were solved to simulate regular waves in the absence of wind stress, and the resulting water velocities agreed with Stokes theory for waves. The RANS velocity field was then used to predict the transport of buoyant particles representing oil droplets under the effect of non-locally generated turbulence. The RANS eddy viscosity exhibited an increase with depth until reaching a maximum at approximately a wave height below the mean water level. This was followed by a gradual decrease …