Smoke-free air policies: past, present and future

Smoke-free policies have been an important tobacco control intervention. As recently as 20 years ago, few communities required workplaces and hospitality venues to be smoke-free, but today approximately 11% of the world's population live in countries with laws that require these places to be smoke-free. This paper briefly summarises important milestones in the history of indoor smoke-free policies, the role of scientific research in facilitating their adoption, a framework for smoke-free policy evaluation and industry efforts to undermine regulations. At present, smoke-free policies centre on workplaces, restaurants and pubs. In addition, many jurisdictions are now beginning to implement policies in outdoor areas and in shared multiunit housing settings. The future of smoke-free policy development depends on credible scientific data that documents the health risks of secondhand smoke exposure. Over the next 20 years smoke-free policies will very likely extend to outdoor and private areas, and changes in the types of tobacco products that are consumed may also have implications for the nature and scope of the smoke-free policies of the future.     

Output feedback and dynamical sliding-mode control of power converters

Using the underlying idea of the most widely accepted controller for power converters, the current-mode control, a new dynamical and sliding-mode control for dc–dc power converters, is proposed. The controller requires only voltage measurements; is easy to design; is robust under load and input voltage variations, exhibits fast response and does not depend on the load (although a knowledge of the load range is necessary to tune the controller). In spite of these features, it can be easily implemented using standard electronics components. The stability analysis is carried out using the discontinuous (large signal) nonlinear model. This analysis provides a set of controller admissible parameters to keep closed-loop system stability.     

Effect of heat treatment and chemical composition on the corrosion behavior of Ni–Al intermetallics in molten (Li + K) carbonate

The corrosion performance of several Ni–Al alloys in 62 mol% Li₂CO₃–38 mol% K₂CO₃ at 650 °C has been studied using the weight loss technique. Alloys included 50Ni–50Al at.% (NiAl) and 75Ni–25Al at.% (Ni₃Al) alloys with additions of 1, 3 and 5 at.% Li each one, with or without a heat treatment at 400 °C during 144 h. For comparison, AISI-316L type stainless steel was also studied. The tests were complemented by X-ray diffraction, scanning electronic microscopy and micro-analyses. Results showed that NiAl-base alloy without heat treatment presented the lowest corrosion rate even lower than Ni₃Al alloy but still higher than conventional 316L-type stainless steel. In general terms, by either by heat treating these base alloys or by adding Li, the mass loss was increased. This effect was produced because by adding Li the adhesion of the external protective layer was decreased by inducing a higher number of discontinuities inside the grain boundaries. When the alloys were thermally annealed, these irregularities in the grain boundaries disappeared, decreasing the number of paths for the outwards diffusion of Al from the alloy to form the external, protective Al₂O₃ layer.     

Nitriding of Ferrosilicon Powders

The process of nitriding of high-silicon ferrosilicon alloys has been investigated. Formation of Si₃N₄ is found to proceed as a result of nitrogen diffusion into several eutectic melts of iron silicides and silicon. At T > 1673, the process of Si₃N₄ dissociation develops.     

Spanish Melon Landraces: Revealing Useful Diversity by Genomic,Morphological, and Metabolomic Analysis

Spain is a secondary centre of the diversification of the melon (Cucumis melo L.), with high diversity represented in highly appreciated landraces belonging to the Flexuosus and Ibericus groups. A collection of 47 accessions of Flexuosus, Chate, Piel de Sapo, Tendral, Amarillo, Blanco, and Rochet was analysed using a genotyping-by-sequencing (GBS) approach. A total of 66,971 quality SNPs were identified. Genetic analysis differentiated Ibericus accessions and exotic materials (Ameri, Momordica, Kachri, and Agrestis), while Flexuous accessions shared ancestry between them. Within the Ibericus group, no clear genomic distinction could be identified for the different landraces evaluated, with accessions of different landraces showing high genetic similarity. The morphological characterization confirmed that the external colour and fruit shape had been used as recognition patterns for Spanish melon landraces, but variability within a landrace exists. Differences were found in the sugars and acid and volatile profiles of the materials. Flexuosus and Chate melons at the immature commercial stage accumulated malic acid and low levels of hexoses, while Ibericus melons accumulated high contents of sucrose and citric acid. Specific trends could be identified in the Ibericus landraces. Tendral accumulated low levels of sugars and citric acid and high of malic acid, maintaining higher firmness, Rochet reached higher levels of sugars, and Amarillo tended to lower malic acid contents. Interestingly, high variability was found within landraces for the acidic profile, offering possibilities to alter taste tinges. The main volatile organic compounds (VOCs) in Flexuosus and Chate were aldehydes and alcohols, with clear differences between both groups. In the Ibericus landraces, general trends for VOC accumulation could be identified, but, again, a high level of variation exists. This situation highlights the necessity to develop depuration programs to promote on-farm in situ conservation and, at the same time, offers opportunities to establish new breeding program targets and to take advantage of these sources of variation.     

Sea-air flux of CO2 in the Caribbean Sea estimated using in situ and remote sensing data

Empirical relationships between sea surface carbon dioxide fugacity (fCO₂^sw) and sea surface temperature (SST) were applied to datasets of remotely sensed SST to create fCO₂^sw fields in the Caribbean Sea. SST datasets from different sensors were used, as well as the SST fields created by optimum interpolation of bias corrected AVHRR data. Empirical relationships were derived using shipboard fCO₂^sw data, in situ SST data, and SST data from the remote sensing platforms. The results show that the application of a relationship based on shipboard SST data, on fields of remotely sensed SST yields biased fCO₂^sw values. This bias is reduced if the fCO₂^sw-SST relationships are derived using the same SST data that are used to create the SST fields. The fCO₂^sw fields found to best reproduce observed fCO₂^sw are used in combination with wind speed data from QuikSCAT to create weekly maps of the sea-air CO₂ flux in the Caribbean Sea in 2002. The region to the SW of Cuba was a source of CO₂ to the atmosphere throughout 2002, and the region to the NE was a sink during winter and spring and a source during summer and fall. The net uptake of CO₂ in the region was doubled when potential skin layer effects on fCO₂^sw were taken into account.     

Discontinuous <Emphasis Type="Italic">H</Emphasis><Subscript>∞</Subscript> control of underactuated mechanical systems with friction and backlash

Nonlinear H _∞-control is extended to discontinuous mechanical systems with degree of underactuation one, where nonlinear phenomena such as Coulomb friction and backlash are considered. The problem in question is to design a feedback controller via output measurements so as to obtain the closed-loop system in which all trajectories are locally ultimate bounded, and the underactuated link is regulated to a desired position while also attenuating the influence of external perturbations and nonlinear phenomena. It is considered that positions are the only measurements available for feedback in the system. Performance issues of the discontinuous H _∞-regulation controller are illustrated in an experimental study made for a rectilinear plant with friction modified to have a gap in the point of contact between bodies.     

EPR-Characterization of Carbon Inclusions in Boron Carbide

In boron carbide, the dependence of EPR line width (ΔB) with g = 2.0028 on the contents of free carbon, c_C, is used to determine the surface-to-volume ratio ( S / V ) of free carbon inclusions. Consecutive reduction of c_C was conducted by a method of low-vacuum oxidation at a range of temperatures. The amount of a free carbon (a graphite phase) in samples was measured by X-ray. Analysis of changes in ΔB (c_C) has shown that free carbon inclusions at the surface layer of polycrystalline boron carbide particles has S / V two times smaller than that of free carbon inclusions in the interior of polycrystalline boron carbide.