AN ASSESSMENT OF THE EFFECTS OF CRUDE OIL POLLUTION ON SOIL PROPERTIES

Pollution caused by crude oil is the most prevalent problem in the environment. The release of crude oil into theenvironment by oil spills is receiving worldwide attention. The effect of crude oil pollution on soil properties wasinvestigated by achieving a case study in Perisoru, Braila County. It has been achieved a profile until 120 cm and soilsamples were collected according to the methodology and analyzed for some physical and chemical properties. In caseof physical analysis, the values obtained for granulometric fractions were not influenced by the presence of crude oil.Results obtained showed variation in chemical properties of soil. Organic carbon increased from 2.23% for anunpolluted soil to 5.51% in polluted soil. C/N ratios increased from 13.01 for an unpolluted soil to 20.54 in pollutedsoil. Mobile phosphorous and potassium registered in polluted soil similar values with the one characteristic forunpolluted soil. Crude oil at high pollution levels inhibited the growth of crops

Pedestrian-level ventilation in an urban environment adjacent to a river channel: A case study for Bucharest city – Romania

Increasing evapotranspiration in cities, derived from vegetation and water bodies, can effectively mitigate the effect of urban heat island (UHI). This paper presents a study on an urban ventilation solution for Bucharest City in Romania. The solution is based on lifting air volumes from the free surface of Dambovita River, which crosses the city center where UHI has a significant impact, to the roadway and pedestrian level by using cross-flow fans mounted on floating panels planted with vegetation, which are placed at the river banks. The electric motors of the cross-flow fans are powered by PV solar cells. The real optimal value of evapotranspiration (ETRO) was computed for the case of lucerne in order to assess the air temperature at the surface of the floating panel and a numerical study was performed in order to obtain the velocities of the air flow and the temperature field in a domain containing the free surface of the river, the floating panel surface, and the roadway surface (at pedestrian level). It was observed that, at low flow rates, the cooler air reaches the roadway surface in a compact jet due to the Coanda effect - the coherent air jet is of about 30–40 cm above the ground level. For a day with clear sky and no wind conditions a decrease in the air temperature of 4–5 °C can be obtained at the pedestrian level, within a layer of 1 m height. The study opens the possibility to approach such issues at a greater scale in order to assess the viability of appropriate solutions for cooling down the urban heat island as well

A mixed-mode cohesive-zone model accounting for finite dilation and asperity degradation

A cohesive zone model is formulated to describe the mechanics of initiation and propagation of cracks and the associated asperity degradation and nonlinear dilation along structural interfaces of quasi-brittle materials, such as concrete, rocks and masonry, subjected to monotonic or cyclic loading. Using a two-scale approach, a cohesive-law is determined at each point of a smooth macroscale interface by resolving a problem at the micro-scale for a representative interface area (RIA), where the geometry of the asperities is modelled using three differently inclined microplanes. On each microplane a cohesive-frictional cohesive law is then used. In this paper, the finite depth of the asperities is accounted for by considering the progressive reduction in contact area between each couple of interfacing microplanes for increasing opening (macro-scale) relative-displacement. Furthermore, the rupture of the asperities and associated flattening of the fracture surface is captured by a progressive reduction of the inclination angles of the microplanes in the RIA. Numerical examples are reported to assess the sensitivity of the shear-stress slip curves and of the nonlinear dilation upon the geometry of the asperities in the RIA. Numerical-experimental comparisons are then presented to illustrate the predictive capability of the model in simulating granite rock joints subjected to monotonic and cyclic shear loading and the concrete-bar interaction in a pull-out test