Kinetic study of the decompositions involved in the thermal degradation of commercial azodicarbonamide

The transitions and reactions involved in the thermal treatment of several commercial azodicarbonamides (ADC) in an inert atmosphere have been studied by dynamic thermogravimetry analysis (TGA), mass spectrometry and Fourier transform infrared (FTIR) spectroscopy. A pseudo-mechanistic model, involving several competitive and non-competitive reactions, has been suggested and applied to the correlation of the weight loss data. The model applied is capable of accurately representing the different processes involved, and can be of great interest in the understanding and quantification of such phenomena, including the simulation of the instantaneous amount of gases evolved in a foaming process. In addition, a brief discussion on the methodology related to the mathematical modeling of TGA data is presented, taking into account the complex thermal behaviour of the ADC.

An approach for characterising the weathering behaviour of Flysch slopes applied to the carbonatic Flysch of Alicante (Spain)

Various studies indicate that most of the slope instabilities affecting Flysch heterogeneous rock masses are related to differential weathering of the lithologies that make up the slope. Therefore, the weathering characteristics of the intact rock are of great importance for the study of these types of slopes and their associated instability processes. The main aim of this study is to characterise the weathering properties of the different lithologies outcropping in the carbonatic Flysch of Alicante (Spain), in order to understand the effects of environmental weathering on them, following slope excavation. To this end, 151 strata samples obtained from 11 different slopes, 5–40 years old, were studied. The lithologies were identified and their mechanical characteristics obtained using field and laboratory tests. Additionally, the slaking properties of intact rocks were determined, and a classification system proposed based on the first and fifth slake cycles (Id1 and Id5 respectively) and an Index of Weathering (IW5), defined in the study. Information obtained from the laboratory and the field was used to characterise the weathering behaviour of the rocks. Furthermore, the slaking properties determined from laboratory tests were related to the in-situ weathering properties of rocks (i.e., the weathering profile, patterns and length, and weathering rate). The proposed relationship between laboratory test results, field data, and in-situ observations provides a useful tool for predicting the response of slopes to weathering after excavation during the preliminary stages of design.

Ventilated Stone Veneer: Mechanical Behaviour, Calculation Methodologies, Major Pathologies and Existing Tests

The increase of building pathologies related to the use of stone materials and the use of ventilated stone veneers, requires the reformulation of design concepts in building façades and also the reformulation of the architectural project. The aim of this paper is to identify, analyze and evaluate synthetically building pathologies in stone ventilated façades in order to obtain the main technical conditions to be considered in the architectural design, by interpreting its mechanical behavior and capabilities to prevent such pathologies and to ensure the proper features during the building lifetime. The methodology is based on both laboratory stone tests and in situ tests about construction systems, by analyzing physical and mechanical behavior of the outer layer in relation to other building requirements. The results imply the need of proper sizing, specific quality control and practical application of calculation methods, to control high concentration pressures in ventilated façades by reaching appropriate project solutions. In conclusion, the research about different pathologies of stone ventilated façades, the study of their mechanical behavior, their anchorage and their connection with their constructive aspects, will help to improve the construction quality of the stone ventilated façade in buildings and to enhance the use of natural stone in modern architecture.

Aggregation dynamics and foraging behaviour of striped red mullet Mullus surmuletus in the western Mediterranean Sea

Habitat-related heterogeneity of striped red mullet Mullus surmuletus heterospecific foraging assemblages was examined off the coast of Spain. Video-based focal-follows conducted on 122 M. surmuletus assemblages (446 total individuals) revealed an array of attendant species (n = 7) with composition linked to benthic habitat complexity; bare sandy substrata were characterized by homospecific groups of M. surmuletus, while habitats with rock and vegetation attracted a variety of scrounging labrids and sparids. Although the nature of the relationship between M. surmuletus and attendants requires further exploration, the present study indicates that substratum composition can be a driving factor explaining the dynamics of this heterospecific assemblage.