Analysis of the Corrosion Resistance of Bronze to Aluminium (ASTM B 824) in a Corrosive Environment Controlled with an Artificial Seawater Solution

This paper presents the analysis of corrosion resistance of bronzes to aluminum in a controlled corrosive environment. Three alloys were studied CuAl4.5; CuAl7,1 and CuAl10,1 (ASTM B824), whose chemical composition was evaluated by spectrometry (OES). To determine its metal phases, chemical attacks were carried out with FeCl3, HCl in 95% Ethanol and FeCl3, HCl, CrO3 in distilled water. The microstructures obtained were characterized by metallography using two microscopes, an optical and a scanning electron (SEM) and the phases obtained were compared. Subsequently, electrochemical corrosion tests were performed on each alloy. The electrolyte used in the tests was artificial seawater (ASTM D1141) with a pH of 10 ± 0.3. Then, the corrosion products were characterized by EDS and SEM. Once the identification phase was over, the products were removed with a 50% HCl solution. Corrosive attack damage in each microstructural matrix was identified and corrosion rates for each alloy were evaluated. Finally, the corrosion rate data were correlated with the Al and Sn percentages of the alloy. The results show that the higher the increase in aluminum, the lower the corrosion rate, for a maximum limit of Al = 10.11%; Sn = 0.13%; CR = 5,170 mpy; In addition, it was shown that these alloys are effective for marine environments with high salinity. The correlation can be used to estimate the corrosion rate for different pH of the electrolytic medium of any type of ferrous or non-ferrous alloy whose variables are dependent on its chemical composition. Keywords: corrosion, alloy, metallography, microstructure, spectrometry, electrochemistry. Resumen Este artículo presenta el análisis la resistencia a la corrosión de bronces al aluminio en un ambiente corrosivo controlado. Se estudiaron tres aleaciones CuAl4,5; CuAl7,1 y CuAl10,1 (ASTM B824), cuya composición química fue evaluada por espectrometría (OES). Para determinar sus fases metálicas se realizaron ataques químicos con FeCl3, HCl en Etanol al 95% y FeCl3, HCl, CrO3 en agua destilada. Las microestructuras obtenidas se caracterizaron mediante metalografía empleando dos microscopios, un óptico y un electrónico de barrido (SEM) y se compararon las fases obtenidas. Posteriormente, se realizaron ensayos de corrosión electroquímica a cada aleación. El electrolito utilizado en los ensayos fue agua de mar artificial (ASTM D1141) con un pH 10±0.3. Sucesivamente, se caracterizaron los productos de la corrosión mediante microscopia SEM. Una vez terminada la fase de identificación, se removieron los productos con una solución al 50% HCl. Los daños del ataque corrosivo en cada matriz microestructural fueron identificados y las tasas de corrosión para cada aleación fueron evaluadas. Finalmente, se correlacionaron los datos de tasas de corrosión con los porcentajes de Al y Sn de la aleación. Los resultados muestran que a mayor aumento de aluminio existe una menor tasa de corrosión, para un límite máximo de Al=10,11%; Sn=0.13%; CR=5,170 mpy; además, se demostró que estas aleaciones son eficaces para ambientes marinos con alta salinidad. La correlación puede ser utilizada para estimar la tasa de corrosión para diferentes pH del medio electrolítico de cualquier tipo de aleación ferrosa o no ferrosa cuyas variables sean dependientes de su composición química. Palabras claves: corrosión, aleación, metalografía, microestructura, espectrometría, electroquímica

Management Model of Ecological Tourism for the City of Francisco de Orellana

The purpose of the present study is to design a management model of ecological tourism for the city of Francisco de Orellana. Through the compilation of information and tourist offers, and the analysis of biophysical, sociocultural and economic areas, and plants, superstructures and attractions that appeal to tourists, 4 natural and 5 cultural places were identified. With the application of the environmental impact matrix, it was determined that tourist attractions present a high level of contamination due to the presence of the industrial sector and the inadequate handling of dirty water and solid waste. The most affected tourist attractions are: Napo and Payamino rivers, the Yacu eco-park and the boardwalk; throughout the environmental impact matrix they establish obstacles to environmental remediation. With the results obtained, a sustainable tourism management model was designed based on the objectives of Plan Nacional del Buen Vivir and PLANDETUR 2020. The study concludes that the management model will provide a starting point for the development of sustainable tourism activity in the city. Keywords: sustainable tourism, management model, environmental sustainability, government policies, environmental impact, strategic plan. Resumen El objetivo de la presente investigación es diseñar un modelo de gestión del turismo ecológico para la ciudad de Francisco de Orellana. A través de la recopilación de información, oferta turística y el análisis de áreas biofísicas, socioculturales, económicas, planta turística, superestructura turística y el atractivo turístico donde se identificaron 4 lugares naturales y 5 culturales. Con la aplicación de la matriz de impacto ambiental se determinó que los atractivos turísticos presentan un alto nivel de contaminación debido a la presencia del sector industrial y al manejo inadecuado del agua sucia y los residuos sólidos. Los atractivos turísticos más afectados son: Ríos Napo y Payamino, Payamino El eco parque Yacu y el malecón, a lo largo de la matriz de soluciones, establecen alternativas de remediación ambiental. Con los resultados obtenidos, se diseña un modelo de gestión del turismo sostenible basado en los objetivos del Plan Nacional del Buen Vivir y PLANDETUR 2020. Se concluye que el modelo de gestión proporcionará el comienzo para desarrollar una actividad turística sostenible en la ciudad. Palabras clave: turismo sostenible, modelo de gestión, sostenibilidad ambiental, políticas gubernamentales, impacto ambiental, plan estratégico

Development and validation of a dynamic thermal model of a minibus using TRNSYS

[EN] The current paper presents a dynamic thermal model of a vehicle including two thermal zones, one for the front region (driver) and one for the back (passengers). The model, developed in TRNSYS, is able to predict the cabin¿s thermal behaviour under variable ambient temperatures and solar radiation. A minibus was used to validate the model using experimental data for ambient temperature, solar radiation and the indoor temperature of a minibus parked both inside and outside a garage in Torino (Italy). The proposed model accurately reproduces the warm-up and cool-down of the cabin. In addition, the model has been used to calculate the cooling load of the cabin during a summer day, and to quantify the thermal loads under variable ambient conditions. In future work, the model will be used to predict the dynamic performance of the A/C system in an urban driving cycle and to optimise the compressor control strategy.Daniela C. Vásconez-Núñez acknowledges the financial support provided by the CONVOCATORIA ABIERTA 2013-SEGUNDA FASE program, which was funded by the SENESCYT (Secretaría Nacional de Educación Superior, Ciencia, Tecnología e Innovación) (Grant No 2014-AR3R7463) of Ecuador.Vásconez-Núñez, DC.; Gonzálvez-Maciá, J.; Corberán, JM.; Payá-Herrero, J. (2018). Development and validation of a dynamic thermal model of a minibus using TRNSYS. International Journal of Vehicle Design. 77(1/2):87-107. https://doi.org/10.1504/IJVD.2018.098272S87107771/

Analysis of the Thermal Behavior of a Vehicle Cabin Using a Dynamic Thermal Model

This work analyzes the thermal behavior of a vehicle cabin by using a dynamic thermal model, which allows to accurately reproduce the vehicle interior temperature under different external environmental conditions. The thermal model considers heat transfer through the glazed and opaque surfaces of the vehicle using the energy balance method. It considers changes in weather conditions, vehicle geometry, body construction characteristics, types of opaque and glazed surfaces, and existing thermal loads. Experimental tests (with and without solar radiation) were carried out to validate the dynamic thermal model. The model predicts the temperature variations of the air inside the vehicle cabin. The results showed a maximum variation of 1.38 K without solar incidence and 3.78 K with solar radiation. Keywords: dynamic thermal model, vehicle, heat balance, thermal load. Resumen El objetivo principal del presente trabajo fue analizar el comportamiento térmico de la cabina de un vehículo utilizando un modelo térmico dinámico, que permite reproducir de manera precisa el comportamiento de la temperatura interior del vehículo bajo distintas condiciones ambientales externas. El modelo térmico considera la transferencia de calor a través de las superficies acristaladas y opacas del vehículo utilizando el método de balance de energía, para lo cual se toman en cuenta los cambios en las condiciones climatológicas, la geometría del vehículo, las características constructivas de la carrocería, tipos de superficies opacas y acristaladas y las cargas térmicas existentes. Se realizaron ensayos experimentales (con y sin radiación solar) para validar el modelo térmico dinámico. El modelo permite reproducir las variaciones de la temperatura del aire interior de la cabina del vehículo. Los resultados obtenidos muestran una variación máxima de 1.38 K, sin incidencia solar y 3.78 K con radiación solar. Palabras Clave: modelo térmico dinámico, vehículo, balance de calor, carga térmica

Path dependence in energy systems and economic development

Energy systems are subject to strong and long-lived path dependence, owing to technological, infrastructural, institutional and behavioural lock-ins. Yet, with the prospect of providing accessible cheap energy to stimulate economic development and reduce poverty, governments often invest in large engineering projects and subsidy policies. Here, I argue that while these may achieve their objectives, they risk locking their economies onto energy-intensive pathways. Thus, particularly when economies are industrializing, and their energy systems are being transformed and are not yet fully locked-in, policymakers should take care before directing their economies onto energy-intensive pathways that are likely to be detrimental to their long-run prosperity

Transition to kinetic turbulence at proton scales driven by large-amplitude kinetic Alfvén fluctuations

Space plasmas are dominated by the presence of large-amplitude waves, large-scale inhomogeneities, kinetic effects and turbulence. Beside the homogeneous turbulence, the generation of small scale fluctuations can take place also in other realistic configurations, namely, when perturbations superpose to an inhomogeneous background magnetic field. When an Alfvén wave propagates in a medium where the Alfvén speed varies in a direction transverse to the mean field, it undergoes phase-mixing, which progressively bends wavefronts, generating small scales in the transverse direction. As soon as transverse scales become of the order of the proton inertial length dp, kinetic Alfvén waves (KAWs) are naturally generated. KAWs belong to the branch of Alfvén waves and propagate almost perpendicularly to the ambient magnetic field, at scales close to dp. Many numerical, observational and theoretical works have suggested that these fluctuations may play a determinant role in the development of the solar-wind turbulent cascade. In the present paper, the generation of large amplitude KAW fluctuations in inhomogeneous background, as well as their effect on the protons, have been investigated by means of hybrid Vlasov-Maxwell direct numerical simulations. Imposing a pressure balanced magnetic shear, the kinetic dynamics of protons has been investigated by varying both the magnetic configuration and the amplitude of the initial perturbations. Of particular interest here is the transition from quasi-linear to turbulent regimes, focusing in particular on the development of important non-Maxwellian features in the proton distribution function driven by KAW fluctuations. Several indicators to quantify the deviations of the protons from thermodynamic equilibrium are presented. These numerical results might help to explain the complex dynamics of inhomogeneous and turbulent astrophysical plasmas, such as the heliospheric current sheet, the magnetospheric boundary layer, and the solar corona