Iván Martínez

Propiedades del hormigón de árido reciclado fabricado con adiciones, activa e inerte

El trabajo de investigacion presentado en este articulo describe las propiedades fisicas, mecanicas y de durabilidad de los hormigones fabricados con el 25% y 100% de arido grueso reciclado utilizando adiciones activa e inerte (microsilice y filler de escoria de arco electrico). La fase experimental realizada consta de dos etapas: En la etapa 1 se realizo un estudio fisico-mecanico (resistencia a compresion y velocidad de ultrasonido); En la etapa 2 se evaluo la durabilidad de los hormigones reciclados fabricados con adiciones mediante los ensayos de difusion de cloruros, resistividad, absorcion y porosidad, lo que permitio comparar los resultados con el hormigon convencional fabricado con similar dosificacion. Los resultados demuestran que los hormigones reci-clados obtienen propiedades fisicas y mecanicas inferiores al hormigon convencional. Sin embargo, la durabilidad del hormigon reciclado fabricado con adiciones activas mejora las propiedades del hormigon convencional.

Annular Two-Phase Flow Regimen in Direct Steam Generation for a Low-Power Solar System

This study aims to quantify and to model the temperature profile around an absorber tube belonging to a parabolic trough concentrator when fluid is applied at low powers. This study was specifically developed for the Solar Power Plant of the Engineering Institute, National University of Mexico. This work presents experimental results under saturated conditions and low pressures (1.5–3 bars) using water as the thermal and working fluid for direct steam generation (DSG). The control variable was feed flow. Solar irradiance was used as the restriction variable because all experimental tests should be developed under very specific values of this variable (for example, I> 700 \(\text {W/m}^{2}\)). The objective of this experiment was to study the thermal behavior of a temperature gradient around the absorber tube under steady-state conditions and with low flow. Additionally, a theoretical analysis was carried out by means of the homogeneous heat conduction equation in the cylindrical coordinate system using only two dimensions \((\mathrm{r}, \varphi )\). The finite-difference numerical method was used with the purpose of proposing a solution and obtaining a temperature profile. The aim of this theoretical analysis was to complement the experimental tests carried out for direct steam generation (DSG) with annular two-phase flow patterns for low powers in parabolic trough concentrators with carbon steel receivers.

Sustainability in Solar Thermal Power Plants

In the last two decades, there has been growing interest in developing indicators to measure sustainability, which is currently seen as a delicate balance between the economic, environ‐ mental and social health of a community, a nation or even our planet. The current measure of sustainability tends to be an amalgam of economic, social and environmental aspects. Economic indicators have been used to measure the state of regional economies for over a century, and social indicators are largely a phenomenon of the postwar world. However, en‐ vironmental indicators are relatively new and attempt to incorporate the ecosystem into the socio-economic indicators of a study site.