Wastewater modification processes assessment in a stabilization reservoir.
A semi-empirical mechanistic model able to simulate the dynamics of a stabilization reservoir was developed incorporating both settling of particulate components and chemical/biological processes. Several factors affecting the reservoir effluent quality were taken into account: hydraulics and hydrology, solar radiation, atmospheric reaeration, algae, zooplankton, organic matter, pathogen bacteria, and sediment-water interaction. The model quantifies the specific influence of each factor on effluent quality, evaluating the correlation between the different considered factors. State variables included in the model were: algae, dissolved oxygen, organic matter, zooplankton and indicator bacter…
Definition of a fiber macro-model for nonlinear analysis of infilled frames
A common way to model infill-frame interaction is the use equivalent strut macromodels. In most cases these are compression only resistant truss elements defined with a multi-linear axial-force / axial-displacement law. The main difficulty in using this approach is to correctly calibrate such a force-displacement curve (slope of ascending and post-peak branches, critical yielding, peak and residual forces) because of the large number of variables (mechanical and elastic properties of materials) and the different possible damage mechanisms activated for the frame-infill system. Another possible way is using fiber-section elements as diagonal struts. In this case the force-displacement law is…
Predicting the effectiveness of oil recovery strategies in the marine polluted environment
Abstract Many recent studies have focused their attention on the physiological stress experienced by marine organisms in measuring ecotoxicological responses. Here we suggest a new approach for investigating the effects of an anthropogenic pollutant on Life-History (LH) traits of marine organisms, to provide stakeholders and policy makers an effective tool to evaluate the best environmental recovery strategies and plans. A Dynamic Energy Budget (DEB), coupled with a biophysical model was used to predict the effects of a six-month oil spill on Mytilus galloprovincialis' LH traits and to test two potential recovery strategies in the central Mediterranean Sea. Oxygen consumption rates were use…
Oil-degrading bacteria from a membrane bioreactor (BF-MBR) system for treatment of saline oily waste: Isolation, identification and characterization of the biotechnological potential
A collection of forty-two (42) strains was obtained during microbiological screening of a Membrane Bioreactor (MBR) system developed for the treatment of saline oily waste originated from marine transportation. The diversity of the bacterial collection was analyzed by amplification and sequencing of the 16S rRNA gene. Taxonomic analysis showed high level of identity with recognized sequences of seven (7) distinct bacterial genera (Alcanivorax, Erythrobacter, Marinobacter, Microbacterium, Muricauda, Rhodococcus and Rheinheimera). The biotechnological potential of the isolates was screened considering an important factor such as the biosurfactant production. In particular fourteen (14) biosur…
Biodegradation of Crude Oil by Individual Strains and a Mixed Bacterial Consortium in Simulation of Marine Environment
Petroleum hydrocarbons are the most widespread contaminants in the marine environment. The fate of petroleum in sea water is largely controlled by mechanical, physical and chemical factors which influencing the natural transformation of petroleum (oil weathering) and oil bio-degradation. On the basis of these considerations, bioremediation techniques have been developed and improved for cleaning up oil-polluted marine environment as alternative to chemical and physical techniques. To elucidate the cooperative action of mixed microbial populations in the biodegradation of crude oil, we constructed artificial consortia composed of two to three bacteria (Alcanivorax borkumensis strain SK2, Rho…
Shear capacity in concrete beams reinforced by stirrups with two different inclinations
Abstract A model for the estimation of shear capacity in Reinforced Concrete (RC) beams with web reinforcement is provided by introducing a generalization of classical plastic Nielsen’s model, which is based on the variable-inclination stress-field approach. The proposed model is able to predict the shear capacity in RC beams reinforced by means of stirrups having two different inclinations and longitudinal web bars. A numerical comparison with the results of experimental tests and those provided by a Finite Element Model (FEM) based on the well known theory of Modified Compression Field Theory (MCFT) is carried out for validating the robustness of the proposed model. Finally, a set of para…
Isolation and Characterization of Oil-Degrading Bacteria from Bilge Water
Twenty-one oil-degrading bacteria were isolated from bilge water. Based on a high growth rate on crude oil and on hydrocarbon degradation ability, 7 strains were selected (from 21 isolated) for further studies. 16S rRNA gene sequencing showed that isolated strains were affiliated to Bacillus, Pseudomonas and Halomonas genera; in particular, isolate BW-B12 (Bacillus sp., 99%), BW-C12 (Halomonas boliviensis, 99%) and BW-E12 (Halomonas boliviensis, 98%) were the best crude-oil degraders; after 10 days of cultivation in ONR 7a mineral medium supplemented with crude oil as single carbon source BW-B12, BW-C12 and BW-E12 showed a degradation rate of 80, 60 and 59%, respectively. The strains showed…