No abstract

This paper describes how hydrogen transport affects the severity of hydrogen embrittlement in 300M and AerMet100 ultra high strength steels. Slow strain rate tests were carried out on specimens coated with electrodeposited cadmium and aluminium-based SermeTel 1140/962. Hydrogen diffusivities were measured using two-cell permeation and galvanostatic charging methods and values of 8.0x10-8 and 1.0x10-9 cm 2 s-1 were obtained for 300M and AerMet100, respectively. A two-dimensional diffusion model was used to predict the hydrogen distributions in the SSR specimens at the time of failure. The superior embrittlement resistance of AerMet100 was attributed to reverted austenite forming around martensite laths during tempering.

Virgin and recycled polyethylene terephthalate (PET) has been examined for the production of composites with additions of 5-20% by weight of sand particles. Density and compressive strength were estimated using virgin (V-PET) and recycled PET (R-PET). Scanning electron microscope (SEM) equipped with energy dispersive X-ray (EDX) spectroscopy was used to characterize the morphology and elemental composition of the composites. Also, thermogravimetric analysis (TGA) was used to find degradation temperature on both types of polymer. On the other hand, a streamlined life cycle assessment (SLCA) was made for the different composites to get environmental impacts. The results indicated that a maximum of 52.94 MPa and 52.03 MPa on compressive strength were obtained for virgin and recycled PET without sand, respectively. With the addition of sand, compressive strength decreases in both cases. The best performance was found at 5% sand addition, which causes a reduction of 9.07% and 16.68% for V-PET and R-PET composites, respectively. Environmental results show that resource extraction is the dominant life stage; meanwhile, gas residues are the dominant environmental impact in both types of composites. R-PET composites are the best environmentally friendly option because they used recycled material, which in return recovers part of the embodied energy used to make the primary production. The results show it could be explored the potential to be used the composites in pavement blocks or architectonic elements.

En la actualidad, las ciudades afrontan múltiples amenazas tanto naturales como antrópicas, se presentan problemas urbanos que a su vez tienen una cierta relación con el desarrollo de las comunidades, sin embargo, cuando a la incidencia antrópica se le suman las fuerzas naturales se propician los desastres. Por ello es importante estudiar los desastres desde todos los ámbitos. En esta investigación, se presenta una zonificación de la amenaza ante deslizamientos en el barrio El Mortiñal, localizado en la zona de ladera al noroccidente del municipio de Santiago de Cali. El estudio se realizó a partir de la aplicación del método de Mora y Vahrson, con lo cual se determinaron las áreas de mayor afectación y ocurrencia del fenómeno de deslizamiento en la zona de estudio. Como resultado de la zonificación, se obtuvo que las áreas correspondientes a amenazas altas y medias son las más representativas en el mapa obtenido. Es por ello que hay que trabajar con las comunidades locales, en primera medida dando a conocer el riesgo al que se encuentran expuestos y establecer medidas de gestión para minimizar los futuros daños generados por este tipo de amenaza en el área de estudio.