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Digital fabrication with concrete (DFC) is fast becoming an attractive alternative for components (i.e., façades, urban furniture) and structural typologies (i.e., short‐span footbridges, columns, floor systems) for which complex geometries derived from particular aesthetical criteria and/or construction time constrictions are governing parameters. Additionally, some authors claim that this process allows improving the sustainability of structures, as less material is necessary compared to traditional concrete solutions, thus reducing greenhouse gas emissions linked to material consumption. Nonetheless, the environmental implications of DFC are still under scrutiny and remain objectively unquantified. In this study, a sustainability assessment model to allow decision‐makers to evaluate and compare concrete footbridge alternatives—from the sustainability perspective—including those constructed by means of 3D printed concrete (3DPC) techniques, is presented. The proposed approach is based on the MIVES method. For this purpose, the most representative criteria and indicators of sustainability identified are measured and weighted‐aggregated in a decision‐making tree. The sustainability index (SI) of each alternative is the outcome derived from the application of the model, and the SI was used as reference for evaluating the alternatives. The sustainability of 3D‐printed footbridges is quantified and compared to other concrete‐based solutions: traditional reinforced cast‐in‐place and precast concrete, as traditional solutions, and ultra‐high performance precast concrete and textile‐reinforced concrete, as innovative alternatives. The results of the analysis lead to conclude that 3D‐printed footbridges have positive impacts on environmental and social indicators, but economic indicators still need to be improved to attain a competitive solution. The approach proposed herein to assess the sustainability of footbridges can be extended to other cases and stakeholders' preferences by adapting the components of the method to sensitivities and particular boundary conditions of other scenarios. [ABSTRACT FROM AUTHOR]

Nowadays, the use of tobacco biomass as an energy source is being valued. Therefore, it is important to know the processes that take place during combustion and pyrolysis, as well as the substances that are formed. In this work, we study the compounds obtained during the decomposition of NNN as a function of temperature under inert and oxidant atmospheres. Moreover, the effect of the addition of SBA-15 and MCM-41 is analyzed. Two different techniques, i.e., TG/FTIR (low heating rates) and EGA Py/GC/MS (high heating rates), are used. At low temperatures NNN is almost unaltered, but it is volatilized and dragged by the carrier gas. When increasing the temperature, decomposition takes place, with pyridines being one of the most abundant compounds observed. The main compound obtained during the pyrolysis are 3- pyridinecarbonitrile, myosmine and nornicotine, which are precursors of NNN. When NNN is mixed with SBA-15, the decomposition of the NNN nitrosamine is favored at low temperatures where the yield in pyridine compounds increases. The catalysts modify the temperature and intensity of the processes, especially under an oxidative atmosphere where the residue is oxidized, showing a third loss of weight. These materials modify the compositions of gases, mainly under an O2 atmosphere (3-pyridinecarbonitrile and myosmine showed the major effect). SBA-15 with fibrous morphology obtains the best reductions at pyrolysis conditions. [ABSTRACT FROM AUTHOR]

Interatrial blocks are considered a new important risk factor for atrial fibrillation and cerebrovascular events. Their prevalence and clinical implications have been reported in general population and several subgroups of patients but no data from HIV-infected populations, with a non-negligible prevalence of atrial fibrillation, has been previously reported. We conducted a cross-sectional study in a previously enrolled cohort of randomly selected middle-aged HIV-infected patients who attended our hospital and were clinically stable. Patients underwent both a 12-lead rest electrocardiogram and clinical questionnaires while epidemiological, clinical and HIV-related variables were obtained from electronic medical records and interviews with the patients. Electrocardiograms were then analyzed and codified using a standardized form by two trained members of the research team who were blinded to clinical variables. We obtained electrocardiograms from 204 patients with a mean age of 55.22 years, 39 patients (19.12%) presented an interatrial block, 9 (4.41%) advanced and 30 (14.71%) partial. Patients with interatrial block had a lower nadir lymphocyte CD4 count (124 vs 198 cells, p = 0.02) while advanced interatrial blocks were associated to older age (62.16 vs. 54.95 years, p = 0.046) and hypertension (77.8% vs. 32.3%, p = 0.009). We did not find differences regarding baseline CD4 lymphocyte count or CD4/CD8 lymphocyte ratio. Clinical variables and functional capacity among patients with or without interatrial block were similar. In a cohort of clinically stable HIV infected patients the prevalence of interatrial blocks, specially advanced, is high and associated to previously known factors (age, hypertension) and novel ones (nadir CD4 lymphocyte count). [ABSTRACT FROM AUTHOR]

This paper analyses the redistributive effects generated by the subsidization of urban public transport services. We estimate a two-stage model that takes into account both car ownership decisions and expenditure in urban public transport. In this way, we are able to measure the long run effects of income changes. Under the assumption that the user is the final beneficiary of the subsidies, and computing the share of the fare that is subsidized, we measure the progressiveness of the subsidies for different income groups and city sizes. Urban public transport subsidies are shown to be progressive. In larger urban areas this effect is considerably more important than in small ones. [ABSTRACT FROM AUTHOR]

SBA-15 has been employed as a tobacco additive with the objective of reducing the toxic and carcinogenic components in tobacco smoke. The effect of the synthesis conditions (temperature, time, and stirring rate) on this application was studied in this paper. The SBA-15 was characterized (RDX, N2 adsorption isotherms, SEM and apparent density), mixed with the 3R4F reference tobacco, and smoked under standard conditions. The composition of the gas and condensed fractions also was analyzed. The morphology of the material plays an important role on this application and is highly influenced by the three variables studied. Long fibers show improved efficiency compared to short fibers. The tar reduction effect was improved when increasing the time of synthesis. Nevertheless, a maximum was observed with temperature (40 °C) and stirring rate (700 rpm). The optimal synthesis conditions obtained were 24 h, 40 °C and 700 rpm, yielding reductions as high as 68% for tar, 67% for nicotine, and 31% for CO. The scaling-up process has only been reported in terms of grams but never in a preindustrial scale (around 4 kg), and thus the results of this analysis show a promising material with properties and behavior similar with respect to the sample synthesized at laboratory scale. [ABSTRACT FROM AUTHOR]

Different SBA-15 (SBA, Santa Barbara Amorphous) materials were synthetized at different temperature and time during of the hydrothermal treatment. The obtained SBA-15 were characterized by N2 adsorption isotherms, scanning electron microscopy (SEM), X-ray diffraction (DRX), and density in order to establish the influence of these variables on their properties. Mixtures of the obtained catalysts with 3R4F tobacco were prepared and smoked under the ISO 3308 conditions. Temperature of the hydrothermal treatment slightly affects the tars that evolved in the smoking process of the corresponding catalyst tobacco mixtures. Contrarily, the time of the hydrothermal treatment has a marked effect on the reductions of toxic compounds in the smoke. Developed porosity has a positive correlation with the observed tar reduction, whereas the apparent density has a negative correlation with the reduction in toxicity. Moreover, the removal of the supernatant liquors during the hydrothermal treatment does not strongly modify the properties of the materials and may represent an interesting simplification of the process. [ABSTRACT FROM AUTHOR]