Water quality trend analysis of Cheurfas II dam, Algeria

The northwestern part of Algeria is characterized by a semi-arid climate which has created semi-permanent rivers and dams with low filling rates. It is important to preserve the water resource, which is becoming increasingly scarce. Additionally, it is worth indicating that the mobilized surface waters are continually under threat of significant organic pollution. Indeed, the dam of Cheurfas II, in the northwestern part of the country, is indicative of this situation. In order to establish a diagnosis of the state of the temporal evolution of water quality, time series of 11 variables indicating the presence of organic pollution in this dam were thus analyzed. The data collected were analyzed using the Mann-Kendall test to look for significant trends and the Webel-Ollech test to detect the presence of seasonality. The results obtained showed increasing trends in dry residues, organic matter, phosphates and dissolved oxygen. However, variables like BOD5, COD and NO-3 showed decreasing trends. As for the variables NH+4, NO-2 and pH, they presented no trend. Finally, the water volume of the dam exhibited a significant increase. In addition, no seasonality was detected in the variables studied, with the exception of the PO43- time series and water volume. These findings indicate that the watershed of the dam received pollutants from different origins, in particular industrial pollutants. This makes water biodegradability difficult to achieve.

Indirect electrochemical degradation of acetaminophen: process performance, pollutant transformation, and matrix effects evaluation

Acetaminophen (ACE), a highly consumed pharmaceutical, was degraded in aqueous matrices by reactive chlorine species (RCS) electrogenerated using Ti/IrO2 electrodes. Although this pollutant has been extensively treated by electrochemical techniques, little information is known about its degradation in fresh urine by electrogenerated RCS, and the understanding of its transformations using analyses of atomic charge. In this work, these two topics were discussed. Initially, the effect of current (10-40 mA) and supporting electrolyte (considering typical ions present in surface water and urine (Cl- and SO42-)) on the electrochemical system was evaluated. Then, the kinetics and primary transformations products involved in the elimination of ACE were described. It was found that, in distilled water, the process at 40 mA in NaCl presence led to 100 % of ACE degradation (10 min, 0.056 Ah L-1). Theoretical analyses of atomic charge for ACE indicated that the amide group is the most susceptible to attacks by RCS such as HOCl. On the other hand, degradation of acetaminophen in synthetic fresh urine was slower (21% of degradation after 60 min of treatment) than in distilled water. This was attributed to the other substances in the urine matrix, which induce competition for the degrading RCS.

Distributed Optimal Control for Distribution Systems with Microgrids

The growing consumption of electricity as well as the progressive development of new technologies implies that the power system is increasingly automated with the purpose of having a more efficient and economical operation. This development drives the system to a Smart Grid, a large-scale cyber-physical network covering different energy generation technologies, storage and communications enabling real-time information exchange and control. In this work, we present an optimal distributed control based on the consensus+innovation technique, where each agent of the network obtains information from its neighbours. Simulations on a microgrid system based on an IEEE 14-Bus reference system demonstrate the effectiveness of the approach. Convergence is observed in the microgrid system under different scenarios in the physical and communications network.

Hybrid Algorithm for the detection of Pixel-based digital image forgery using Markov and SIFT descriptors

Today, image forgery is common due to the massification of low-cost/high-resolution digital cameras, along with the accessibility of computer programs for image processing. All media is affected by this issue, which makes the public doubt the news. Though image modification is a typical process in entertainment, when images are taken as evidence in a legal process, modification cannot be considered trivial. Digital forensics has the challenge of ensuring the accuracy and integrity of digital images to overcome this issue. This investigation introduces an algorithm to detect the main types of pixel-based alterations such as copy-move forgery, resampling, and splicing in digital images. For the evaluation of the algorithm, CVLAB, CASIA V1, Columbia, and Columbia Uncompressed datasets were used. Of 7100 images evaluated, 3666 were unaltered, 791 had resampling, 2213 had splicing, and 430 had copy-move forgeries. The algorithm detected all proposed forgery pixel methods with an accuracy of 91%. The main novelties of the proposal are the reduced number of features needed for identification and its robustness for the file format and image size.

Photocatalytic treatment based on TiO2 for a coal mining drainage

The aim of the present work was to evaluate the effectiveness of a heterogeneous photocatalyst based on TiO2 in the treatment of coal mining drainage which contains a variety of heavy metals and high concentration sulfates and sulfides. The photocatalytic behavior of the commercial reference Sigma Aldrich and the different materials synthesized using the Sol-gel methodology with surface modifications using sulfation and fluorination processes were analyzed. To find a possible correlation between the physicochemical properties of photocatalysts and their behavior, a characterization was carried out using X-Ray Diffraction (XRD), X-Ray Fluorescence spectrometry (XRF), Fourier transform infrared spectroscopy (FT–IR), UV–Vis diffuse reflectance Spectra (UV-Vis DRS), N2 physisorption, X-ray photoelectron spectroscopy (XPS), and particle size analysis. Results indicated that the modification of the TiO₂ prepared in the laboratory using sulfation and fluorination allowed the successful control of the physicochemical properties of this oxide. However, commercial TiO2 showed the greatest effectiveness in removing metals such as: Fe, Cu, Cr, and As after a photocatalytic reaction for a maximum of 1 hour under continuous nitrogen flow and a light intensity of 120 W/m2.

Editorial

Editorial

A mechanical model to determine upheaval buckling of buried submarine pipelines

Thermal loads in submarine pipelines generate an axial compressive load that can force the pipeline to buckle, leading to failure if these loads are not considered in the design. Buried pipes are constraint to displacements in all directions, which leads to a high compressive load in the longitudinal axis and makes the pipes more vulnerable to buckling. If buried pipes under thermal loads do not buckle, a high-stresses state takes place when it is combined with high-pressure conditions. In this work, a simple mechanical model to determine the axial buckling load of a buried pipeline is proposed. The model is based on a simply supported beam subjected to a distributed transverse load representing the soil uplift resistance obtained from a referenced model, and an axial compressive load that represents the effective axial force and is computed according to the DNV-RP-F110. Additionally, the pipe–soil system is analyzed through a non-linear finite element model to compare the results with the analytical solution. The proposed simple mechanical model can capture the upheaval buckling behavior and provides results that are consistent with the numerical analysis, specifically for the two main parameters evaluated, namely, the initial pipe curvature and the magnitude of the transverse load.

Optimal design and performance evaluation of tuned mass damper inerter in building structures

This paper concerns the numerical performance evaluation of multi-degree-of-freedom systems equipped with Tuned Mass Dampers-Inerter (TMDIs); a passive control device used for the mitigation of mechanical vibrations induced by dynamic loads. The inerter device is commonly used to increase the apparent mass of classics tuned mass dampers (TMDs), improving its seismic performance. To evaluate the TMDI action, three case studies are employed, determined from three real buildings of Medellin city from low, medium to high rise (30 meters, 97 meters, and 144 meters, respectively). Optimum design parameters are found using a metaheuristic optimization based on the differential evolution method, first, for the minimization of the horizontal peak displacements, and then, for the minimization of the root mean square (RMS) response of displacements. Besides, the case studies are assessed using eight seismic accelerations records representative of the literature. Finally, the seismic performance is evaluated on each case study considering different levels of inertance induced by the inerter device: 5%, 20%, and 50% with respect to the total mass of the building, for which it is observed a better dynamic behavior when TMDIs with lower values of inertance are implemented.

Assessment of noise and ozone levels in a small industrial urban area

Monitoring environmental parameters in urban centers has become a critical step for health risk assessment. In this study, conducted in the industrial park of Mirandela (Portugal), an environmental monitoring system consisting of a meteorological station, a class 1 smart sound sensor and three reference optical gas analyzers were deployed to measure noise levels, tropospheric ozone concentrations, carbon monoxide, and nitrogen oxides, during winter and spring of 2019. The interdependence among all variables was evaluated, and legal compliance was assessed according to the European Union (EU) target values for ozone. Higher concentrations of nitrogen oxides and carbon monoxide were observed during rush hours, while ozone concentrations increased as a consequence of the emissions of primary pollutants after sunrise reaching their maximum values at about 13:00 to 14:00h. Regarding the Accumulated Ozone Exposure (AOT), both target values set by the EU for AOT40 vegetation and forest have been exceeded. For AOT60, the observed values were below target; however, the threshold for NET60 was exceeded even before the end of 2019. Noise levels were higher during rush hours, because of higher traffic intensity; however, noise level indicators (Lden, Ln) remained within the legal limits. It was possible to realize that urban traffic is the most relevant source of noise and local air pollution. These results can be used to define strategies that may improve the environmental performance of the studied industrial park.

Renewable energy in sustainable supply chain: A review

In the search of sustainable process and products, ecofriendly policies have been developed over the years, aiming at reducing the environmental impacts as a step toward sustainability. Among the environmental impacts, alternatives to mitigate the greenhouse gas emissions - GHG stand out due to the concerns with climate change. Then, the development and use of renewable resources become relevant. Considering that supply chains are intense in energy consumption and GHG emissions (since involves processes related to supply, production, transport, consumption), it becomes relevant to investigate if the management of sustainable supply chain are considering the renewable energies in their processes. Therefore, this paper aims at mapping the role of renewable energies in the context of sustainable supply chain, analyzing the literature published at Web of Science database - WoS about the subject. The main researchers, organizations, collaboration networks were presented, and the 21 most cited studies were mapped in this paper. The research was carried out with the papers published at WoS until 2019, using VantagePoint software to handle information. The findings show that the research about renewable energy in the context of sustainable supply chain has been growing, especially since 2010. Moreover, biomass, biofuels and photovoltaic energy were the most recurrent sources of renewable energy studied by most cited papers. However, the theme presented itself as new and that there are still potential to be explored.