The electrodissolution and passivation of mild steel in alkaline sulphide solutions

The electrodissolution and passivation of mild steel in alkaline sulphide solutions at 25°C is investigated by the use of steady state and transient electrochemical techniques and by scanning electron microscopy and energy dispersive X-ray analysis. The electrodissolution and passivation processes are explained by the initial competitive adsorption of OH−, HS− and H2O and the subsequent charge transfer and proton transfer processes involving the OH and HS adsorbed species. The former is responsible for the passivation of the metal by an oxide metal layer while the second species undergoes two different reactions yielding in one case a precipitated mackinawite film on the metal, which is a poorly protective layer, and in the other a soluble Fe(II) species which can be detected by chemical analysis. The contribution of the reactions starting from each adsorbed species depends on the HS−/OH− concentration ratio in the solution. The initiation of pitting on iron is also explained through the postulated reaction pattern.Instituto de Investigaciones Fisicoquímicas Teóricas y AplicadasFacultad de Ciencias Exacta

A comparative pitting corrosion study of mild steel in different alkaline solutions containing salts with sulphur-containing anions

The localized corrosion of mild steel in alkaline solutions containing a salt with a sulphurcontaining anion (sodium sulphate, sodium sulphite, sodium thiosulphate, potassium thiocyanate and sodium sulphide) is studied by using potentiostatic and potentiodynamic techniques complemented with scanning electron microscopy. Alkaline solutions containing one of those salts produce pitting of mild steel at potential values more positive than those of the active-passive transition of iron in base. In the presence of either thiocyanate or thiosulphate anion iron pitting takes place through sulphide formation which reacts at the electrode surface yielding poorly protective ferrous sulphide. At potential more positive than the breakdown potential the kinetic behaviour fits a competitive surface reaction mechanism involving the formation of the passive film and the nucleation and growth of a ferrous sulphide salt layer. The proposed reaction model reproduces the corresponding experimental current-transients.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicada

Totalitarismo y biopolítica

Despite his frequent confusion, the paradigms of totalitarianism and biopolitics are very heterogenous. While the book of Arendt, The Origins of Totalitarianism, still seems inscribed inside the framework of the philosophy of history, although inverted and turned toward the lost origin (the Greek polis), the category of biopolitics, themed in the middle of seventy`s by Michel Foucault, but already anticipated in the work of Nietzsche, prevents all linear reconstruction of the relationship between past and future. Is the direct connection between politics and biological life, which is established from a certain point of view, radically alters the modern political philosophy and apprehends it from a new horizon of sense. On the other hand, while Arendt, despite the deconstruction of the idea of human rights, doesn’t make a real critique of right, Foucault explicitly discussed the link between individual rights and State sovereignty.     A pesar de su frecuente confusión, los paradigmas de totalitarismo y biopolítica resultan muy heterogéneos. Mientras el libro de Hannah Arendt, Los orígenes del totalitarismo, todavía parece inscrito dentro del marco de la filosofía de la historia, aunque sea invertido y vuelto hacia el origen perdido (la polis griega), la categoría de biopolítica, tematizada a mitad de los años setenta por Michel Foucault, pero anticipada ya en la obra de Nietzsche, impide toda reconstrucción lineal de la relación entre pasado y presente. La conexión directa entre política y vida biológica, que se establece desde un cierto punto de vista, altera radicalmente la filosofía política moderna y la aprehende desde un nuevo horizonte de sentido. Por otra parte, mientras Arendt, pese a la deconstrucción de la idea de derechos humanos, no elabora una verdadera crítica del derecho, Foucault discute explícitamente el nexo entre derecho individual y soberanía estatal

Reflexiones sobre el derecho a la ciudad como derecho constitucional en Nuestra América para la democratización y la vida buena

El derecho a la ciudad, puede ser comprendido como la posibilidad de construir una ciudad en la que se pueda vivir dignamente, en la que todos y todas puedan reconocerse como parte de ella. Sin embargo, pensar la ciudad implica trascender las discusiones que se reducen a bregar solamente por el reconocimiento jurídico del derecho a la vivienda, el hábitat, el medio ambiente y a la centralidad. En este marco de las discusiones intrínsecas a este derecho emergente, el presente escrito pretende ahondar en el debate del reconocimiento del derecho a la ciudad como derecho constitucional en Nuestra América, para la democratización y la vida buena, retomando los aportes de Lefevbre y Harvey, pero también abordando una serie de saberes nuestroamericanos que han ido desarrollándose en la búsqueda de una alternativa al capitalismo neoliberal, que parten primeramente del reconocimiento de nuestro continente como punto de inicio no sólo del desarrollo del capitalismo global, sino de la modernidad y la colonialidad que configuraron las formas y los ritmos de un mundo urbanizado a lo largo y ancho del planeta

The electrodissolution and passivation of mild steel in alkaline sulphide solutions

The electrodissolution and passivation of mild steel in alkaline sulphide solutions at 25°C is investigated by the use of steady state and transient electrochemical techniques and by scanning electron microscopy and energy dispersive X-ray analysis. The electrodissolution and passivation processes are explained by the initial competitive adsorption of OH−, HS− and H2O and the subsequent charge transfer and proton transfer processes involving the OH and HS adsorbed species. The former is responsible for the passivation of the metal by an oxide metal layer while the second species undergoes two different reactions yielding in one case a precipitated mackinawite film on the metal, which is a poorly protective layer, and in the other a soluble Fe(II) species which can be detected by chemical analysis. The contribution of the reactions starting from each adsorbed species depends on the HS−/OH− concentration ratio in the solution. The initiation of pitting on iron is also explained through the postulated reaction pattern.Instituto de Investigaciones Fisicoquímicas Teóricas y AplicadasFacultad de Ciencias Exacta

Nitrous oxide emissions in maize on mollisols in the Pampas of Argentina

The objectives of this study were i) to measure the soil N2O fluxes in a cropping system currently adopted by farmers of the region (FP), and in an ecologically intensified cropping system (EI) over two consecutive maize growing seasons (2011–12 and 2012–13), and ii) to relate N2O fluxes to soil factors. Gas fluxes were measured using vented static chambers, from October through April in each season. Fluxes of N2O ranged from 3 to 88 μg N2O-N m−2 h−1 in 2011–12, and between 3 and 97 μg N2O-N m−2 h−1 in 2012–13. There was a significant (p 0.05) effect on cumulative N2O emissions, which were, on average across two seasons, 558 g N2O-N ha−1 for the EI treatment and 578 g N2O-N ha−1 for the FP treatment. Cumulative N2O emissions tended to be 20% greater over 153 days in 2012–13 compared with over 156 days in 2011–12 mainly due to differences in total and timing precipitations. As there were no differences in cumulative N2O emissions between managements but grain yield was higher under EI, this treatment had lower yield-based N2O emissions (75 g N2O-N Mg−1 grain) compared with FP treatment (94 g N2O-N Mg−1 grain). The results showed that a moderate increase in N rate (10 kg N ha−1), combined with N split-application and UAN (urea-ammonium nitrate) as N source, as well as other crop management practices, can be a viable alternative to improve maize productivity without increasing the N2O environmental impact.EEA BalcarceFil: Picone, Liliana. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; ArgentinaFil: Bayer, Cimélio. Universidade Federal do Rio Grande do Sul. Faculdade de Agronomia. Departamento de Solos; BrasilFil: Videla, Cecilia. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina.Fil:. Rizzalli, Roberto Héctor. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina.Fil: Casanave Ponti, Sheila M. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Andrade, Fernando Héctor. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: García, Fernando O. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina

Evaluation of Potential Pain Biomarkers in Saliva and Pain Perception After Corneal Advanced Surface Ablation Surgery

Purpose: To evaluate the evolution of a set of proposed pain biomarkers in the saliva of subjects following Advanced Surface Ablation (ASA), in order to determine their validity as objective pain measures. Methods: A multicenter, prospective, and descriptive study was carried out to assess the variations between biomarkers and perceived pain. The Inclusion criteria were healthy subjects who underwent a bilateral, alcohol-assisted surface ablation with epithelial removal (ASA). Pain intensity before and after surgery was assessed by Visual Analog Scale (VAS) and the Numeric Pain Rating Scale (NPRS). Cortisol, sAA, sIgA, testosterone, and sTNF alpha RII were assayed at four-time points (V0, baseline; V1, pre-surgery; V2, 1 hr post-surgery, and V3, 72 hrs post-surgery). Comorbidities and Hospital Anxiety and Depression (HADS) questionnaires were administrated before and at 6 hrs after the surgery. All patients were treated with cold patches, topical steroids, topical cold antibiotics, and benzodiazepines after ASA surgery. A descriptive analysis of biomarkers and pain intensity evolution and the agreement between biomarkers and pain was performed. Results: Concentration of sIgA and sTNF alpha RII post-surgery was significantly higher at each visit compared to baseline (p-value: 0.053, p-value: < 0.001, respectively). Relations between VAS scale score and putative biomarker variations were not statistically significant except for the sIgA but only at visit 0 (p-value: 0.024). The HADS questionnaire showed anxiety scores between 0 and 7 in all patients before and at 6 hrs after surgery. Conclusion: In this study, sIgA and sTNF alpha RII are the two potential biomarkers that present correlation with the VAS and these salivary substances showed acceptable levels of reproducibility in healthy subjects

Economic groups, corporate networks and think tanks. The case of the Centro de Estudios Públicos in Chile

This article examines the deployment of business power in Chile in a specific space such as the think tank Centro de Estudios Públicos (CEP). According to data from the year 2021, there are 79 companies, legal entities, and individuals that made an annual donation to the institution. This number of donors motivates the main objective of this article: to analyze the corporate power structure that is interlaced around this think tank and the companies that finance it. Regarding the methodology, social network analysis has been used to identify how corporate networks are organized when companies share directors and advisors (interlocking directorates). Respecting to the results, two fundamental questions are answered: 1) which are the central companies in the corporate network of the CEP's financiers? and 2) who are the closest and intermediate directors and advisors of this net of CEP funders? The leadership of economic groups like Angelini, Matte, and Luksic in the corporate network shows how these relations are intertwined. In addition, it exhibits how 40 directors of the CEP held positions in companies that provide economic stimulus to the think tank. Finally, it is concluded about the reticular structure of the power of productive elites in Chile and their consequences related to the resilience of neoliberalism in this country

El nuevo teatro cordobés: Teatro Estable de la Universidad Nacional de Córdoba (TEUC) Libre Teatro Libre (LTL) La Chispa. 1969-1975

Este libro presenta trabajos producidos en el transcurso de nuestra investigación sobre Teatro, Política y Universidad, Córdoba, 1965-1965 desarrollada en el CEA, con aval y luego subsidios de SECyT, UNC, entre los años 1996 y 1999, con dirección del Dr. Horacio Crespo. Y luego, con lugar de trabajo en FFyH, con subsidios de SECyT, UNC, entre 2000-2011, con Dirección de Adriana Musitano y Co-dirección de Nora Zaga). El proyecto se desarrolló en relación con el llamado “nuevo teatro cordobés”, fenómeno teatral del período que va desde el Cordobazo, en 1969, hasta el inicio de la dictadura de 1976. Nos ocupamos especialmente del teatro universitario, del estudio y análisis de las producciones de los tres grupos ligados a la UNC, el Teatro Estable el LTL y La Chispa . Consideramos sus puestas teatrales –innovadoras y transgresoras– y sus textos en su carácter de críticas a la sociedad, a las convenciones y cuando de creaciones colectivas se trataba, por la recusación de las propias estructuras del teatro, tales el autor, las interacciones verticales entre actores, directores, técnicos, entre otras cuestiones relevantes. Comprobamos que, tanto el teatro universitario como el independiente que conformó ese nuevo teatro cordobés, se caracterizó por unir una mirada crítica sobre la realidad y la política, sumando el humor y las innovaciones, mediante obras que situaban a los espectadores frente a sus problemas, abiertas a lo regional latinoamericano, y a la vida política de aquellos años setenta. Estas producciones del nuevo teatro cordobés priorizaron el lengua analógico, la imagen, la expresividad de los cuerpos y gestos. Buscaron nuevas formas de comunicación teatral, distinguiéndose por el uso de formas y estilos populares reformulados, y en pocos casos, por incoporar distintos medios tecnológicos. Las innovaciones y trabajos sobre el humor y la política, se abordan en los capítulos de Musitano, Zaga, Fobbio, Castañares, y Gallardo. Y, desde distintas perspectivas analíticas, se presentan estudios sobre las diversas puestas en escenas de los grupos, en algunos casos interesa la política del momento, por ejemplo, Castañares lo hace con respecto del Gran Acuerdo Nacional (GAN), de 1971, y sobre la puesta de Pettraglia como apropiación de un texto de la comedia clásica antigua. En otros, el conocimiento sobre las puestas en escena se logra con la metodología propuesta por Patrice Pavis (2000 y 2002), tal el caso de Palasí también con respecto al TEUC. Ambos autores, además, reconocen las representaciones sociales y las figuras retóricas que confluyen en la poética del grupo. (Véase para completar esta perspectiva en el FDVVirtual el trabajo de Alberto Palasí, y su análisis de las puestas del TEUC y la actividad creativa del actor, y cómo los cuerpos en acción resultan productores de sentido). Mariela Heredia en su investigación advierte que el “nuevo teatro cordobés” al que pertenece el Elenco universitario, resulta una construcción de los medios y que, además, desde ese espacio periodístico y desde la UNC se acercaron entre sí los grupos, configurando aún más fuertemente la identidad en sus vínculos con lo que hoy se denomina Nueva Izquierda. En la segunda parte del libro, transitado el teatro de autor, se abre la vía de la creación colectiva

A comparative pitting corrosion study of mild steel in different alkaline solutions containing salts with sulphur-containing anions

The localized corrosion of mild steel in alkaline solutions containing a salt with a sulphurcontaining anion (sodium sulphate, sodium sulphite, sodium thiosulphate, potassium thiocyanate and sodium sulphide) is studied by using potentiostatic and potentiodynamic techniques complemented with scanning electron microscopy. Alkaline solutions containing one of those salts produce pitting of mild steel at potential values more positive than those of the active-passive transition of iron in base. In the presence of either thiocyanate or thiosulphate anion iron pitting takes place through sulphide formation which reacts at the electrode surface yielding poorly protective ferrous sulphide. At potential more positive than the breakdown potential the kinetic behaviour fits a competitive surface reaction mechanism involving the formation of the passive film and the nucleation and growth of a ferrous sulphide salt layer. The proposed reaction model reproduces the corresponding experimental current-transients.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicada