Pedro Antonio Márquez Aguilar

Closed cycle of recycling of waste activated sludge

The recycling of waste activated sludge (WAS) formed in the process of biological purification of sewage is an urgent ecological problem. In the present work, two ways of recycling of WAS containing from 8 to 30% free water, namely, the synthesis of a carbon-containing component and synthesis of porous building ceramics (bricks) with the use of WAS and waste carbonizate, have been considered. For the preparation of a carbon adsorbent, the carbonization of WAS has been carried out in an argon atmosphere. For the synthesis of ceramics, clay-cullet-tezontle-WAS mixtures with different contents of the components have been used. Sintering has been performed in air. It has been established that, in treatment of WAS at 600 °C for 30 min, better adsorption properties are obtained due to the presence of free carbon bonds. The efficiency of water purification from dyes (methylene blue) depends on the standard conditions: the methylene blue concentration, cabonizate-to-solution ratio, and exposure time of the carbonizate in solution. The use of wet WAS makes it possible to exclude the addition of water from the traditional scheme of preparation of a plastic semiproduct, i.e., realize a water-saving technology. The introduction of low-melting cullet, basalt, and WAS powders into red clay makes enables us to reduce substantially the sintering time of porous bricks (down to 8 h) and vary their strength properties.

Aluminum Strain Measurement by Beam Propagation

In mechanics of materials it is important to know the stress–strain relation of each material in order to understand their behaviour under different loads. Optical methods are used for determine different kind of stresses and interferometry is the most used tool. In this work it is presented a new alternative to determine the stress–strain based in one beam which is reflected in the surface of the material while it is in a compression test as the ASTM indicates. It is taken the material as a reflective surface which acts as a spherical mirror and it will scatter light, the scattered area will increase as the deformation increases. The reflected beam is analysed applying beam propagation equations and Digital Image Processing for getting the increase of the scattered area. Finally it is plot the relation between the applied stress and the beam propagation. There is also presented the accuracy, sensitivity and a theoretical demonstration of the method.

Digital image correlation used to analyze a brick under compression test

ABSTRACT In mechanics of materials it is important to know the stress-strain relation of each material in order to understand their behaviour under different loads. The brick is one of the most used materials in structural mechanics and they are always under loads. This work is implemented using one beam and the speckles created by its reflection. Strain field measurement with noninvasive techniques is needed in order to sense rubber-like materials. We present an experimental approach that describes the mechanical behavior of structural materials under compression tests, which are done in a universal testing machine. In this work we show an evaluation of the displacement field obtained by digital image correlation allowing us to evaluate the heterogeneous strain field evolution observed during these test.In mechanics of materials it is important to know the stress-strain relation of each material in order to understand their behaviour under different loads. The brick is one of the most used materials in structural mechanics and they are always under loads. This work is implemented using one beam and the speckles created by its reflection. Strain field measurement with noninvasive techniques is needed in order to sense rubber-like materials. We present an experimental approach that describes the mechanical behavior of structural materials under compression tests, which are done in a universal testing machine. In this work we show an evaluation of the displacement field obtained by digital image correlation allowing us to evaluate the heterogeneous strain field evolution observed during these test.