Ecoinhibidores para mitigar los efectos de corrosión en artefactos antiguos

Muestras de artefactos antiguos de la batería de San Rafael-Bocachica –Colombia, fueron analizados por microscopia estereoscópica, Ramán, FT-IR-MIR y DRX, con el fin de determinar su grado de corrosión. Paralelamente se desarrollo la optimización de la extracción de cera presente en el bagazo de caña, residuo agroindustrial de la zona, paso primario en la obtención de un ecoinhibidor de corrosión enriquecido con  propoleo y una base de fosfato de molibdeno y zinc

Ecoinhibidores para mitigar los efectos de corrosión en artefactos antiguos

Muestras de artefactos antiguos de la batería de San Rafael-Bocachica –Colombia, fueron analizados por microscopia estereoscópica, Ramán, FT-IR-MIR y DRX, con el fin de determinar su grado de corrosión. Paralelamente se desarrollo la optimización de la extracción de cera presente en el bagazo de caña, residuo agroindustrial de la zona, paso primario en la obtención de un ecoinhibidor de corrosión enriquecido con  propoleo y una base de fosfato de molibdeno y zinc

Heterogeneous Photocatalytic Pilot Plant for Cyanide Decontamination: A Novel Solar Rotary Photoreactor

During the gold extraction in opencast mining, many hazardous substances, such as cyanide, are spilled into the water bodies. This study’s aim was to develop a novel rotary photocatalytic TiO2-based reactor to remove cyanide from polluted water using a rotary concentrator photoreactor (RCPR). This pilot-scale reactor was tested with synthetic cyanide water at concentrations from 0.05 to 50 ppm, varying the pH and commercial TiO2 load. The optimal conditions from experimental data were 87.4% of cyanide removal and catalyst load of 0.30 g/L at pH 9.5. Further, samples of cyanide water from an opencast gold mine were treated, achieving removal of 68.7% after 240 min. Our value-added is the rotary motion of the set of four glass tubes, achieving satisfactory performance, which is promising for cyanide wastewater treatment with a more compact footprint than a standard compound parabolic collector (CPC) solar photoreactor. Thus, it was possible to reduce mass and heat transfer limitations with a simple design by considering this photoreactor as a photocatalytic process intensifier. Copyright © 2022 by ASME

Películas pasivantes protectora de óxido/carbonato de cinc en la zona splash de estructuras metálicas de acero al carbón

Películas pasivantes con zinctape® fueron inducidas, sobre estructuras de acero al carbón de un muelle expuesto en ambiente salino y aireación diferencial, el brazo de descarga, con elevado desgaste mecánico y los pilotes de soporte, fueron limpiados con ultra alta presión y realizadas soldaduras tipo cañuelas (casquetes) para reconstruir las zonas perdidas. Las columnas fueron protegidas con zinctape® desde la zona de splash hacia arriba, con un cinta de cinc de 100 mm de ancho, espesor de la capa de cinc  0,08mm, espesor de adhesivo electro conductivo  de 0,025 mm. Paralelamente fue  habilitado el sistema de protección catódica con corriente impresa. Las estructuras fueron rehabilitadas en un 100% por acción conjunta de los dos métodos de protección. Uno químico al inducir con la cinta, la  formación de una capa delgada, resistente, compacta y estable (insoluble en agua) del carbonato de cinc y  otro fisicoquímico como corriente impresa. Esta mitología es amigable con el medio ambiente y económicamente rentable, con una duración asegurada de mínimo 10 años

Diminishing benefits of urban living for children and adolescents’ growth and development

Optimal growth and development in childhood and adolescence is crucial for lifelong health and well-being1–6. Here we used data from 2,325 population-based studies, with measurements of height and weight from 71 million participants, to report the height and body-mass index (BMI) of children and adolescents aged 5–19 years on the basis of rural and urban place of residence in 200 countries and territories from 1990 to 2020. In 1990, children and adolescents residing in cities were taller than their rural counterparts in all but a few high-income countries. By 2020, the urban height advantage became smaller in most countries, and in many high-income western countries it reversed into a small urban-based disadvantage. The exception was for boys in most countries in sub-Saharan Africa and in some countries in Oceania, south Asia and the region of central Asia, Middle East and north Africa. In these countries, successive cohorts of boys from rural places either did not gain height or possibly became shorter, and hence fell further behind their urban peers. The difference between the age-standardized mean BMI of children in urban and rural areas was <1.1 kg m–2 in the vast majority of countries. Within this small range, BMI increased slightly more in cities than in rural areas, except in south Asia, sub-Saharan Africa and some countries in central and eastern Europe. Our results show that in much of the world, the growth and developmental advantages of living in cities have diminished in the twenty-first century, whereas in much of sub-Saharan Africa they have amplified