Numerical Simulation of Gas Injection in Vertical Water Saturated Porous Media

We present numerical simulations of drainage induced by air injection in a vertical water-saturated Hele-Shaw cell filled with glass microbeads. We use the macroscale Subsurface Transport Over Multiple Phases (STOMP) simulator developed by the Pacific Northwest National Laboratory’s Hydrology Group. To trigger fingering, we use random permeability fields consistent to capillary entry pressure fields. We compare the numerical results to our own experimental results shown in a previous study. We analyze the effects of the microheterogeneity degree as well as the macroscopic parameters on the gas saturation results. The main objective of the work is to investigate how microscopic effects could be accounted for by macroscopic variables during drainage.     

Macrobenthic community colonization and community development in dredged material disposal habitats off coastal Louisiana

We examined marine benthic macroinvertebrate colonization and community structure at multiple spatial scales (study areas, reference and disposal sites, and depth zones within sites) within a 3-day period at three relatively widely separated (ca 60 km) dredged material disposal areas (Mermentau and Atchafalaya Rivers and Freshwater Bayou) in coastal Louisiana. Study areas had different histories of dredged material disposal, but all three are subject to frequent natural habitat disturbances (e.g. freshets). Nine phyla and 51 taxa were represented among the three study areas at reference (R) and disposal (D) sites (Freshwater Bayou: 21(R), 18 (D); Mermentau River: 14 (R), 17 (D) and Atchafalaya River: 38 (R), 40 (D)). Only 15 taxa were common to all three study areas. At the Freshwater Bayou, average taxa richness and abundance responded to water depth, not sites. These response variables averaged higher mean values at the Mermentau River disposal than at the reference site. No consistent pattern in the average of these response variables was detected between sites at the Atchafalaya River. Multidimensional scaling ordination and non-parametric multivariate inferential analysis provided a distinctly different picture of community structure within study areas compared to parametric analyses. A relatively moderate to strong separation in community structure between sites was detected depending on study area. Non-parametric multivariate inferential analysis detected significant differences in internal community structure at the scale of stations and sites within study areas. The weight of evidence suggests that frequent natural disturbances explain differences in macrobenthic animal community structure more than effects of dredged material disposal.     

Perils of using speed zone data to assess real-world compliance to speed limits

Objective: Real-world driving studies, including those involving speeding alert devices and autonomous vehicles, can gauge an individual vehicle's speeding behavior by comparing measured speed with mapped speed zone data. However, there are complexities with developing and maintaining a database of mapped speed zones over a large geographic area that may lead to inaccuracies within the data set. When this approach is applied to large-scale real-world driving data or speeding alert device data to determine speeding behavior, these inaccuracies may result in invalid identification of speeding. We investigated speeding events based on service provider speed zone data.

Methods: We compared service provider speed zone data (Speed Alert by Smart Car Technologies Pty Ltd., Ultimo, NSW, Australia) against a second set of speed zone data (Google Maps Application Programming Interface [API] mapped speed zones).

Results: We found a systematic error in the zones where speed limits of 50–60 km/h, typical of local roads, were allocated to high-speed motorways, which produced false speed limits in the speed zone database. The result was detection of false-positive high-range speeding. Through comparison of the service provider speed zone data against a second set of speed zone data, we were able to identify and eliminate data most affected by this systematic error, thereby establishing a data set of speeding events with a high level of sensitivity (a true positive rate of 92% or 6,412/6,960).

Conclusions: Mapped speed zones can be a source of error in real-world driving when examining vehicle speed. We explored the types of inaccuracies found within speed zone data and recommend that a second set of speed zone data be utilized when investigating speeding behavior or developing mapped speed zone data to minimize inaccuracy in estimates of speeding.     

Integration of the recycling processes to the life cycle analysis of construction products

The life cycle analysis of a product enables one to assess its environmental quality. A simple, transparent method taking into account the processes of recycling in the life cycle is developed here. It permits dealing with all types of open loops of all sectors. The principles on which the proposed method is grounded are discussed.     

Real time instability of flow close to a scour affected abutment

Environmental Fluid Mechanics - For centuries, the interaction between the transport and hydrographic networks represents a significant issue in a country such as France. For example, the French...