Self-heating and deicing conductive cement. Experimental study and modeling

This research studies the self-heating produced by the application of an electric current to conductive cement pastes with carbonaceous materials. The main parameters studied were: type and percentage of carbonaceous materials, effect of moisture, electrical resistance, power consumption, maximum temperature reached and its evolution and ice melting kinetics are the main parameters studied. A mathematical model is also proposed, which predicts that the degree of heating is adjustable with the applied voltage. Finally, the results have been applied to ensure that cementitious materials studied are feasible to control ice layers in transportation infrastructures.

High speed imaging and algorithms for non invasive vibrations measurement

Comunicación presentada en EVACES 2011, 4th International Conference on Experimental Vibration Analysis for Civil Engineering Structures, Varenna (Lecco), Italy, October 3-5, 2011.

Temperature influence on the physical and mechanical properties of a porous rock: San Julian's calcarenite

This work discusses the results from tests which were performed in order to study the effect of high temperatures in the physical and mechanical properties of a calcarenite (San Julian's stone). Samples, previously heated at different temperatures (from 105 °C to 600 °C), were tested. Non-destructive tests (porosity and ultrasonic wave propagation) and destructive tests (uniaxial compressive strength and slake durability test) were performed over available samples. Furthermore, the tests were carried out under different conditions (i.e. air-cooled and water-cooled) in order to study the effect of the fire off method. The results show that uniaxial compressive strength and elastic parameters (i.e. elastic modulus and Poisson's ratio), decrease as the temperature increases for the tested range of temperatures. A reduction of the uniaxial compressive strength up to 35% and 50% is observed in air-cooled and water-cooled samples respectively when the samples are heated to 600 °C. Regarding the Young's modulus, a fall over 75% and 78% in air-cooled and water-cooled samples respectively is observed. Poisson's ratio also declines up to 44% and 68% with the temperature in air-cooled and water-cooled samples respectively. Slake durability index also exhibits a reduction with temperature. Other physical properties, closely related with the mechanical properties of the stone, are porosity, attenuation and propagation velocity of ultrasonic waves in the material. All exhibit considerable changes with temperature.

Regio and diastereoselective multicomponent 1,3-dipolar cycloadditions between prolinate hydrochlorides, aldehydes and dipolarophiles for the direct synthesis of pyrrolizidines

A general synthesis of highly substituted pyrrolizidines can be performed by a multicomponent 1,3-dipolar cycloaddition using proline ester hydrochlorides, aldehydes and dipolarophiles, at room temperature without catalysts or in the presence of AgOAc (5 mol %). In the case of (2S,4R)-4-hydroxyproline derivatives it is possible to obtain enantioenriched pyrrolizidines with high control of the regio- and diastereoselectivity affording the adducts 2,4-trans-2,5-trans according to an endo-approach and a S-dipole geometry of the in situ generated azomethine ylide. For proline esters a similar regioselectivity and endo-diastereoselectivity are observed when the dipole promotes an α-attack. However, when ethyl glyoxylate is used as aldehyde component the γ-attack of the S-ylide takes place preferentially giving rise the opposite regioselectivity for acrylic dipolarophiles, being crucial the role of silver acetate. In this case, the exo-adducts with a 2,3-cis-2,5-trans relative configuration are diastereoselectively obtained. In addition, computational studies have also been carried out to shed light on the origins of the diastereo- and regioselectivity observed for the described 1,3-dipolar cycloadditions.

Radon gas. Environmental concentration measures and remediation actions in exposed buildings

The main contribution to the radiological impact from natural radiation received by general population is due to the emission of radon (222Rn). The objective of this project is the study of radon gas as a radioactive element in our buildings (existing and future constructions) to avoid its influence in interior rooms. The proposed methodology reflects different aspects of natural radioactivity in buildings, their sources, their control criteria and regulatory framework; aspects related to the presence of radon in our constructions, entryways, measurement methodology for indoor environmental concentration are studied; other protection solutions and remediation measures in both existing buildings and new construction projects are analyzed. In conclusion, the paper presents previous evaluation tools, the analysis of existing concentration and the choice of the most appropriate mitigation / remediation measures depending on each case, through the establishment of different architectural proposals to plan actions against radon where necessary.

How buildings visualise client and architect: The problem that today’s user is typically not the client

An article presented at the last ICAT- conference stated at the end that buildings at all times tend to picture the people who had them erected. This paper aims to show the correctness of that statement. To this end, it will examine a number of typical residential buildings dating from the beginning of the seventeenth century up to today, investigate who had the buildings erected, and relate that to the performance of the buildings. This relation analysis will mainly use the scale but also the degree of diversity in function and appearance as factors. Furthermore, using economic data and data on the buildings to identify patterns, it will investigate how size of the property and relative size of the capital interest behind the building has developed. Since the authors live in Copenhagen and Copenhagen is very typical in its historical development, buildings and environments in and around the centre of Copenhagen are used as examples.