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Green inhibitors are an important way to decrease the corrosion rate of different industrial metals. The present work shows the corrosion behavior of the mild steel medium (MS) in ...hydrochloric acid 1 M by the aqueous extract of Artemisia Herba Alba (AHA), which is an green sustainable inhibitor to reduce its corrosive action by exploiting a variety of techniques and methods namely: Weight loss, electrochemical techniques electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PDP, SEM-EDX, XPS and theoretical calculations for the majority molecule. Hydrodistillation is the extraction method that has been used to prepare the aqueous extracts. Otherwise, phytochemical screening characterization of different parts of the plant was applied to show the proportions of chemical compounds that exist in the plants. The highest inhibition efficiency obtained is 92% for 0.4 g/L of AHA aqueous extract in 1 M HCl at 303 K. PDP study confirmed that the AHA extract is of mixed-kind inhibitor. A CPE, Q determined by fit and graphical methods plotted by synthetic data, was utilized. To characterize the mild steel surface, scanning electron microscopy was also used; SEM/EDX allowed the investigation of the AHA effect on the surface of mild steel specimens. To comprehend the adsorption mechanism of AHA extract for MS in the 1 M HCl, XPS technique was accomplished. Theoretical approaches based on chemical quantum calculations and molecular dynamics simulation clearly explains the mode of adsorption of the majority molecule on the iron surface.
This contribution reviews previous contributions to ancient history by means of social network analysis and historical network research. In trying to ascertain common methodological challenges and ...identifying strategies of overcoming them, it attempts to provide guidance for future research projects.
Two quinoxaline derivatives, 2-(2,3-dimethoxyphenyl)-1,4-dihydroquinoxaline (HHQ) and 2-(2,3-dimethoxyphenyl)-6-nitro-1,4-dihydroquinoxaline (NHQ) were selected as inhibitors for mild steel corrosion ...in 1 M HCl using experimental techniques and theoretical approaches (DFT and the simulations of Monte Carlo (MC) and molecular dynamics (MD)). The results obtained by electrochemical polarization measurements show that these two molecules inhibit the corrosion rate of mild steel in the corrosive media. The HHQ and NHQ inhibitors showed a mixed, predominantly anodic character, decreasing the rate of cathodic and anodic corrosion reactions. As reported in electrochemical impedance spectroscopy (EIS) tests, the adsorbed inhibitor molecules built up a pseudo-capacitive response of the interface. The inhibition efficiency is reduced by the effect of the electron attractor group NO2 in the NHQ inhibitor. Adsorption is in accordance with the Langmuir isothermal model. Scanning electron microscopy (SEM) identified that the formation of a protective layer of inhibitor on the surface of mild steel. Analyses inhibited Electrolyte by UV–visible spectroscopy provide concrete evidence on the complexation of iron cation with both quinoxaline molecules in 1 M HCl. The results obtained by the theoretical approaches through the different methods via DFT, MC and MD simulations show a satisfactory concordance with the results of the experimental part.
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•Corrosion inhibition performance has been investigated using EIS and polarization techniques.•Surface analysis of mild steel was examined by SEM/UV–Vis.•The adsorption properties were discussed by computational studies.
El presente trabajo tiene por objetivo reflexionar sobre la Sociología Jurídica como disciplina, a partir de sus conceptualizaciones, campos de estudio y principales enfoques teóricos. Aborda desde ...un enfoque crítico el estudio del Derecho como fenómeno social, y su comprensión desde los enfoques sociales en los que opera y de los significados que los sujetos construyen a partir de sus normas. Igualmente revisa las principales y diversas explicaciones teóricas acerca del Derecho de los clásicos autores de la Teoría Sociológica. Lejos de concluir que esta diversidad teórica es contradictoria o confusa en los análisis del Derecho y del sistema jurídico, debemos admitir que –por el contrario– la perspectiva sociológica es multiparadigmática y transitarla propone un interesante desafío.
The present work reports the development of a catalyst based on palladium (Pd) coordination compound covered and surrounded by Printex L6 (PL6C) carbon material and its application toward improving ...the selectivity and electrocatalysis involving the production of hydrogen peroxide via oxygen reduction reaction (2e–ORR). The morphology and structure of the Pd-based complex/PL6C catalyst were characterized by clusters of an average size of 2.4 µm composed of 1.3% (w/w) Pd2+ metal. Compared to the unmodified PL6C, the application of the Pd-based complex/PL6C led to a shift in the ORR onset potential by 250 mV vs Ag/AgCl 3 M to more positive potentials and 97% selectivity toward H2O2 production. This electrocatalytic effect was attributed to the π-π interactions between the dz2 orbital of the Pd2+ metal and the carbon close to the oxygenated functional groups present in the carbonaceous matrix. The mechanistic-theoretical analyses conducted showed that the oxygenated carboxyl functional group COOH is the group that favors most significantly the interaction between O2 and hydronium ions toward the formation of the OOH* species; the presence of the Pd2+ metal further contributes toward favoring this interaction. In addition, the Pd-based complex was found to influence the Laplacian of the electron density (V2ρ) for the bond between the carbon close to the COOH group and the oxygen atom of the ORR intermediates, and this facilitates the conversion of adsorbed O2 species into OOH* intermediates and increases the desorption capacity of the species from the active site, leading to H2O2 formation.
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EcoHealth and One Health are two major approaches broadly aimed at understanding the links between human, animal, and environment health. There have been increasing calls for convergence between the ...two. If convergence is desired, greater clarity regarding the underlying theoretical assumptions of both approaches is required. This would also support integrated research to effectively address complex health issues at the human, animal and environment interface. To better understand the areas of overlap and alignment, we systematically compared and contrasted the theoretical assumptions of both approaches.
We aimed to gain a more in-depth understanding of the ontological, epistemological and methodological underpinnings of EcoHealth and One Health in order to identify areas of difference and overlap, and consider the extent to which closer convergence between the two may be possible.
We undertook a scoping review of literature about the ontological, epistemological and methodological positions of EcoHealth and One Health, and analyzed these according to Lincoln, Lynham and Guba's paradigm framework.
EcoHealth and One Health are both collaborative, systems-focused approaches at the human, animal, and ecosystem health interface. EcoHealth typically leans towards constructivist-leaning assumptions. Many consider this a necessary aspiration for One Health. However, in practice One Health remains dominated by the veterinary and medical disciplines that emphasize positivist-leaning assumptions.
The aspirations of EcoHealth and One Health appear to overlap at the conceptual level, and may well warrant closer convergence. However, further shared discussions about their epistemological and ontological assumptions are needed to reconcile important theoretical differences, and to better guide scopes of practice. Critical realism may be a crucial theoretical meeting point. Systems thinking methods (with critical realist underpinnings), such as system dynamics modelling, are potentially useful methodologies for supporting convergent practice.
•EcoHealth and One Health share considerable overlapping theoretical aspirations.•Clearer understanding of the aims and scope of both approaches is needed.•Closer convergence may be possible using a diverse range of methods and worldviews.•Calls for more critical, constructivist approaches in One Health may support this.•Systems thinking methods may support beneficial integration of these approaches.
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