The seas and oceans of the planet provide a wide range essential resources. However, marine ecosystems are undergoing severe degradation due to unsustainable exploitation consumption patterns linear economy. On other hand, many economic activities linked sea generate large amount waste, leading negative impacts, such as cost treating or disposing this waste. A case in point is bivalve mollusc production: purification process needed avoid risk diseases through faecal contamination. present...

This work proposes a green material for artificial reefs to be placed in Galicia (northwest Spain) taking into account the principles of circular economy and sustainability ecosystem. New concrete formulations marine applications, based on cement and/or sand replacement by mussel shells, are analyzed terms resistance abrasion. The interest lies importance canning industry Galicia, which generates important quantities shell residues with negative environmental consequences. Currently, tests...

A mathematical model for the total heat flow obtained in differential scanning calorimetry (DSC) experiments from polymers with enthalpic relaxation is proposed. It limited to glass transition and range of temperature cases where only non‐reversing process taking place. The consists a mixture functions representing capacity glassy non‐glassy fractions, progress flow. Optimal fittings were performed on experimental data, two thermoplastics different aging times. Considering which represent...

Abstract A typical problem when analyzing the kinetics by dynamic TGA of polymer degradation consists in that different models can fit equally well, or model does not data. It has been suggested this is due to presence overlapping processes. High resolution helps clarify some cases, but many other cases remains unsolved. In work, a curve showing processes degradation, thermal fitted multiple logistic regression model. The function mixture functions where each single weighed factor represents...

This work studies the influence of saline atmospheric corrosion on fatigue strength 6061-T6 aluminum alloy. For this purpose, alloy was subjected to tests in a salt spray chamber at different exposure times (1, 2, and 3 months) according ASTM B117 standard. The morphological study pits carried out by confocal microscopy. Subsequently, were performed variable stresses whose maximum stress (Smax) between 30% 95% yield (S0) order keep them within zone elastic behavior material. Data analyzed...

The influence of several metallic ions on Sulfolobus BC activity was examined. maximum tolerance to increasing quantities metal in cultures grown copper concentrate determined after a period progressive adaptation. In addition, the concentrations capacity microorganisms oxidize ferrous iron and sulphur studied individually. all cases silver, mercury, ruthenium molybdenum inhibited bacterial growth. use adapted led an increase oxidation rate both substrates, which related activity.

Abstract The oxidation stabilizing effect of a substituted phenol on soy and palm based biodiesels was investigated according to the ASTM E2009 standard. Pressure differential scanning calorimetry (PDSC) measurements were used evaluate influence oxygen pressure. A relationship derived describe correlation between onset temperature Additional standard (DSC) thermogravimetric analysis tests performed in order other thermal effects additive. different behavior both fuels explained basis their...

En este estudio se analiza la respuesta frente al desgaste de aceros austeníticos tipo Hadfield, en función del contenido manganeso, partiendo con proporciones dentro intervalo 4 6 % manganeso. El análisis tribológico ha realizado mediante ensayos pin on disk, según norma ASTM G99-05, y los resultados obtenidos han relacionado dureza microestructura cada muestra determinándose que, para aceros, resistencia no sólo depende material sino que ve muy influida por el distribución precipitados existentes.

This study deals with the wear experienced in welded joins for pipelines. Its aim is to minimize problems caused by this wear. An analysis carried out on tribological behaviour of three crucial areas within welding: base metal, heat affected zone and weld bead itself. The differences mechanical properties between these are evaluated. Moreover, various alternatives welding process proposed an effort improve overall join.

This paper presents an alternative to the materials traditionally used in manufacture of coal mills for coating wedges. For this purpose, we designed and tested ten new austenitic steels with medium manganese content. The thermal structural stability hardness were evaluated after different heat treatments. subjected hyperquenching tempering between 100 900 °C. A metallographic analysis each sample was then performed determine their stability, Brinell measured. Later, wedges two alternatives...

Mediante la adición de boro al metal líquido, bien en forma metálica o bórax, ferroboro, carburo boruro cálcico, se pueden obtener fundiciones grafito esferoidal sin necesidad inoculantes especiales. Estas estado bruto colada presentan una matriz perlítica con más menos que suele estar orlado ferrita formando ojos buey. Por tratamiento térmico normalizado, consigue eliminar orla ferrítica y tener enteramente perlítica. recocido, puede por temple revenido martensita revenida. En el presente...