Contaminant source identification in groundwater by means of artificial neural network

In a desired environmental protection system, groundwater may not be excluded. In addition to the problem of over-exploitation, in total disagreement with the concept of sustainable development, another not negligible issue concerns the groundwater contamination. Mainly, this aspect is due to intensive agricultural activities or industrialized areas. In literature, several papers have dealt with transport problem, especially for inverse problems in which the release history or the source location are identified. The innovative aim of the paper is to develop a data-driven model that is able to analyze multiple scenarios, even strongly non-linear, in order to solve forward and inverse transport problems, preserving the reliability of the results and reducing the uncertainty. Furthermore, this tool has the characteristic of providing extremely fast responses, essential to identify remediation strategies immediately. The advantages produced by the model were compared with literature studies. In this regard, a feedforward artificial neural network, which has been trained to handle different cases, represents the data-driven model. Firstly, to identify the concentration of the pollutant at specific observation points in the study area (forward problem); secondly, to deal with inverse problems identifying the release history at known source location; then, in case of one contaminant source, identifying the release history and, at the same time, the location of the source in a specific sub-domain of the investigated area. At last, the observation error is investigated and estimated. The results are satisfactorily achieved, highlighting the capability of the ANN to deal with multiple scenarios by approximating nonlinear functions without the physical point of view that describes the phenomenon, providing reliable results, with very low computational burden and uncertainty.Comment: Published on Journal of Hydrolog

Novel infiltration method of membranes over activated carbons electrodes

A novel method to modify activated carbons electrodes through addiction of selective ion exchange membrane (IEM) is presented. Nowadays the preferred method to modify an electrode in an electric double layer supercapacitor is to apply a stand-alone membrane in proximity of the electrode itself. This technique produces some drawbacks in terms of dimensions of the device, increase of the internal series resistance and reduction of the total capacitance. With the present method it is possible to use the membrane with a conformal contact with the electrode or directly in the production of the slurry. In particular the first approach studied consists into melting the membrane and casting and drying it under vacuum over activated carbons. This drying process, is performed in a glass oven B-585 from BÜCHI. In this way it is possible to reduce internal resistance of the device, providing good ion selectivity and maintaining a high capacitance. The second approach consists in exploiting the IEM as polymeric functional binder inside the slurry. It is possible to exploit the long chains of ion exchange polymers to bind activated carbons together and onto the substrate. This strategy allows the substitution of common binders like PVDF, with several benefits in terms of reduced electrical resistance, tunable surface charge of the electrodes, reduced cost and increased sustainability

Performance study of a thin film cation exchange membrane on carbon electrode for supercapacitor application

In this work we report a green procedure for the infiltration of a SPEEK solution into a porous carbon electrode resulting in a thin-film cation exchange membrane. The electrodes have been investigated by a morphological point of view, showing the formation of a thin coating infiltrated into the porous carbonaceous matrix, while mechanical peeling of a tape demonstrated the adhesion of the proposed layer. The fabricated electrodes have been analyzed by electrochemical measurement. The 3-electrode cyclic voltammetry measurements allowed to verify the voltage window resulting in an improved negative potential, while the electrochemical impedance spectroscopy showed a reduction of the electrical resistance. The SPEEK electrode was used in a supercapacitor and deeply characterized by electrochemical analysis. The reported findings demonstrate for the first time the possibility to exploit a cation exchange material in thin film configuration for supercapacitor application with improved performance of the device and exclusively involving the use of nontoxic reagents

Design and Performance of an Adsorption Bed with Activated Carbons for Biogas Purification

Organic waste can be efficiently converted into energy using highly efficient energy systems, such as SOFCs coupled to the anaerobic digestion process. SOFC systems fed by biogenous fuels, such as biogas or syngas, suffer long-term stability due to trace compound impacts. It follows that, a mandatory gas cleaning section is needed to remove these pollutants at lower concentrations. This work investigates the adsorption mechanism for micro-contaminant removal through experimental results achieved using solid sorbents. Samples of different sorbent materials were analyzed in the laboratory to determine their performances in terms of sulfur (mainly hydrogen sulfide) and siloxanes (mainly D4-Octamethylcyclotetrasiloxane) adsorption capacities. The analysis shows that the chemical composition of the samples influences the adsorption of H2S (i.e., presence of calcium, iron, copper), while the effect of their textural properties mainly influences the adsorption of siloxane compounds, such as D4. A quantitative analysis was performed considering the influence of gas velocity on adsorption capacity. By increasing the biogas velocity (+45% and +89%), there was an indirect correlation with the H2S adsorption capacity (−27% and −44%). This identified an aspect related to the residence time required to be able to remove and retain the trace compound. The results obtained and summarized were used to develop a strategy for the removal of trace compounds in large-scale plants, e.g., for water purification

The Psychological General Well-Being Index (PGWBI) for assessing stress of seafarers on board merchant ships

Background: In their working activity, seafarers are exposed to high levels of stress that should be accuratelyinvestigated, measured, followed up and, if possible, countered. This is also required by regulations recently entered into force such as the Maritime Labour Convention 2006, recommending to consider special physiological or psychological problems created by the shipboard environment. The choice of the tools for this evaluation is challenging, and a common basic standard usable in a large scale should be identified.Aim: The aim of this study was to evaluate: 1) the suitability of the Psychological General Well-Being Index (PGWBI) questionnaire conducted on board for assessing stress in the sailing seafarers, 2) The presenceof stress in seafarers of different categories (deck officers, engine officers, deck crew, engine crew, chiefstewards/catering staff) monitored by the PGWBI.Materials and methods: 162 male seafarers on board of 7 tankers belonging to the same shipping companywere evaluated through the PGWB questionnaire. Analysis of variance (ANOVA) was used to analyse thedifferences in the scores of the questionnaire.Results: Engine officers exhibited significantly higher anxiety levels than the deck or engine crew, andshowed lower satisfaction than the deck crew. Deck and engine officers revealed higher self-control levelsthan the engine crew. Chief stewards/catering staff showed lower vitality levels than the deck crew.Conclusions: Deck or engine officers should achieve a greater self-control than the crew and this is documentedby the present study. Our findings support the view that management responsibility is more often associated with higher levels of stress. In our opinion, the PGWB questionnaire is a reasonable compromise forobtaining a global evaluation of psychological conditions, including stress of seafarers. It should be therefore considered as a large scale tool for assessing the well-being and eventual stress levels of sailing seafarers

Monitoring of a micro-smart grid: Power consumption data of some machineries of an agro-industrial test site

For the management of a (micro)-smart grid it is important to know the patters of the load profiles and of the generators. In this article the power consumption data obtained through a monitoring activity developed on a micro-smart grid in an agro-industrial test-site are presented. In particular, this reports the synthesis of the monitoring results of 5 loads (5 industrial machineries for crop micronization, corncob crashing and other similar processes). How these data were used within a monitoring and managing scheme of a micro-smart grid can be found in (E. Fabrizio, V. Branciforti, A. Costantino, M. Filippi, S. Barbero, G. Tecco, P. Mollo, A. Molino, 2017) [1]. The data can be useful for other researchers in order to create benchmarks of energy use input appropriate energy demand values in optimization tools for the industrial sector