Microstructural study of a titanium-based biocomposite produced by the powder metallurgy process with TiH2 and nanometric β-TCP powders

A titanium-based composite with Ca-P phases was prepared in situ by powder metallurgy processing with TiH₂ and nanometric β-TCP powders. Crystal phases of the as-fabricated composite are found to be α-Ti, CaTiO₃ and Ti_xP_y phase(s). The Ti_xP_y and CaTiO₃ phases resulted from the reaction between titanium and β-TCP at about 1135 °C. The composite presented a mean compressive strength of 635 MPa and a lower contact angle than pure titanium.     

Cactus stem (Opuntia ficus‐indica Mill): anatomy,physiology and chemical composition with emphasis on its biofunctional properties

Cactus stem (Opuntia ficus‐indica Mill) is native to Mesoamerica and marketed in different forms such as fresh, frozen or pre‐cooked. Worldwide, this vegetable is recognized for its pharmaceutical actions, including its antioxidant, diuretic, anticarcinogenic, anti‐inflammatory, anti‐diabetic, and anti‐hypercholesterolemic properties, as well as their antiviral and antispermatogenic effects. However, not all of these properties have been associated with its chemical composition; therefore, this review aims to present and integrate information available on the physiology and anatomy of cactus stem and its chemical composition, focusing on some of the many factors that determine its biofunctionality. © 2017 Society of Chemical Industry     

Polycarbonate films metalized with a single component molecular conductor suited to strain and stress sensing applications

The paper reports all-organic strain and stress sensitive films that use electrical monitoring approach. The films were prepared by self-metallizing polycarbonate films with the single component molecular conductor [Au(α-tpdt)₂]⁰ (tpdt = 2,3-thiophenedithiolate). It was shown that [Au(α-tpdt)₂]⁰ by its nature is able to form metallic solid material with low crystallinity. Electromechanical tests demonstrated that the developed films are strain-resistive materials with advanced elastic properties: their electrical resistance varies linearly with uniaxial elongation up to relative strain being of 1.0% that is about five times larger than that for conventional metals. The gauge factor of the films is 4.4 and stress sensitivity is 30 Ω/bar. The processing characteristics of polycarbonate films, self-metalized with a metallic [Au(α-tpdt)₂]⁰-based layer, make them potentially useful for engineering flexible, lightweight, strain and pressure sensors. Due to electromechanical characteristics these films are suited to strain sensing applications requiring miniature strain control in a wide deformation range.     

The significance spectrum and EIA significance determinations

The concept of significance is fundamental to environmental impact assessment (EIA). Even though there are many guidelines describing technical characteristics of impacts (such as magnitude, geographic extent, extent and frequency) that should be considered, there has remained a long-standing need for increased clarity on how significance determinations are ultimately reached by significance determiners, those who, on behalf of governments, make a legal determination of significance in EIAs. This involves the application of societal values, in the form of subjective informed judgement, about the acceptability of the predicted impacts. This paper introduces the significance spectrum, a graphic model that illustrates a process for determining significance, using the following steps: (1) determining the threshold of significance for each valued component; (2) weighing the evidence and considering predicted impacts; (3) deciding which side of the threshold the predicted adverse impact falls on; and (4) for unacceptable impacts, deciding if mitigations can make the residual impact acceptable. Concepts such as ecological significance should not be confused with significance in EIAs, which may not only include ecological significance but also considers societal values. We provide specific steps for determining significance that help clarify this fundamental aspect that lies at the core of EIA decision-making.     

Pile burning of cutting debris in stands of hazel (Corylus avellana): An experimental study of smouldering combustion towards the validation of a burning protocol

Smouldering combustion in burning piles was experimentally investigated by studying temperature changes in six piles of 2 m of diameter of cutting debris of hazel (Corylus avellana) for three days after extinction. The piles were monitored using an IR camera and K-type thermocouples. The experiment was designed in order to study how the maximum temperature of the charcoal might be influenced by the individual and interaction effects of both the quality of extinction and the elapsed time until the start of extinction of the piles. The piles that were properly extinguished (i.e. using a high-pressure, homogeneously distributed water flow of 50 l/min for 4 min) had a uniform temperature profile and did not have significant hot spots. The temperature reached equilibrium with the environment in less than 10 h after extinction. In contrast, a smouldering front moved throughout the poorly extinguished piles, which had a wide temperature distribution and hot spots of up to 700 °C. A simulation of windy conditions after three days of experiments on a poorly extinguished pile showed that the reactivation of charcoal combustion was possible. It gave a high-risk scenario to cause a wildfire, with hot smouldering embers being transported by wind flow. The results are of interest to improve pile burning protocols so that the number of wildfires caused by such practices may be reduced.