3,248 research outputs found

    Modelling the exposure to Cronobacter sakazakii by consumption of a cocoa-milk-based beverage processed by pulsed electric fields

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    peer-reviewedM.C. Pina-Pérez is grateful to CSIC for providing a DOCTOR contract linked to the INNPACTO project IPT-2011-1724-060000. This study was carried out with funds from BISOSTAD project PSE-060000-2009-003, Generalitat Valenciana I+D+I emergent research groups GV/2010/064 and CYCIT project AGL2010-22206-C02-01.Infants’ exposure (Nf ) to Cronobacter sakazakii via the consumption of infant-rich-inpolyphenols cocoa-milk-based beverages (CCX-M) treated with high-intensity pulsed electric fields (PEF) was evaluated. Monte Carlo simulation enabled the prediction of the variability in C. sakazakii load in beverages at the time of consumption to be estimated. Different scenarios (initial contamination levels; PEF treatment conditions; and time-temperature combinations of CCX-M beverages storage after treatment) were simulated. Cocoa addition and PEF treatment resulted in the most influential input factors to control bacterial final load. Cronobacter spp. exposure risk was reduced by a maximum of 100 times at 95% of iterations due to addition of cocoa at 5 g/100 mL, corresponding to scenario 3 (PEF: 15 kV/cm–3,000 μs; storage 120 h at 8 °C). Moreover, the probability of illness for a healthy population was reduced from 2.15 × 10-8, in the baseline scenario, to 4.78 × 10-10 due to cocoa addition and application of 15 kV/cm–3,000 μs PEF treatment.BISOSTAD projec

    Influence of the material composition SMD diodes on their environmental impact

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    The influence of the material composition of surface-mount device (SMD) diodes on the environment has been analysed in this research. This impact assessment has been performed by means of an environmental impact calculation through a life cycle assessment (LCA), in which the EcoInvent dataset has been updated and customised, generating a more precise environmental impact analysis by considering the exact material composition provided by several suppliers of diodes and also recycling during the production stage. Considering the EcoInvent diode dataset as a reference, variations from nearly 1640% to only 8.5% of the environmental impact have been achieved. For example, the impact per 1 g of SMD diodes can change the global warming potential from 292 g CO2 eq up to 354 g CO2 eq, whereas for abiotic depletion, values can change from 9.9 × 10-7 up to 1.9 × 10-4 kg Sb eq. The presence of critical raw materials such as antimony, cobalt, or magnesium, together with precious metals as gold or silver, highly influences the environmental impact values obtained, demonstrating the considerable influence on the environmental impact of the material composition of the SMD diodes analysed. © 2021 by the authors. Licensee MDPI, Basel, Switzerland

    Photocatalytic and oxidative synthetic pathways for highly efficient PANI-TIO2 nanocomposites as organic and inorganic pollutant sorbents

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    Polyaniline (PANI)-materials have recently been proposed for environmental remediation applications thanks to PANI stability and sorption properties. As an alternative to conventional PANI oxidative syntheses, which involve toxic carcinogenic compounds, an eco-friendly procedure was here adopted starting from benign reactants (aniline-dimer and H2O2) and initiated by ultraviolet (UV)-irradiated TiO2. To unlock the full potential of this procedure, we investigated the roles of TiO2 and H2O2 in the nanocomposites synthesis, with the aim of tailoring the properties of the final material to the desired application. The nanocomposites prepared by varying the TiO2:H2O2:aniline-dimer molar ratios were characterized for their thermal, optical, morphological, structural and surface properties. The reaction mechanism was investigated via mass analyses and X-ray photoelectron spectroscopy. The nanocomposites were tested on both methyl orange and hexavalent chromium removal. A fast dye-sorption was achieved also in the presence of interferents and the recovery of the dye was obtained upon eco-friendly conditions. An efficient Cr(VI) abatement was obtained also after consecutive tests and without any regeneration treatment. The fine understanding of the reaction mechanism allowed us to interpret the pollutant-removal performances of the different materials, leading to tailored nanocomposites in terms of maximum sorption and reduction capability upon consecutive tests even in simulated drinking water

    Triply green polyaniline: UV irradiation-induced synthesis of highly porous PANI/TiO2 composite and its application in dye removal

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    An environmentally benign procedure for the preparation of polyaniline/TiO2 composites is presented. The UV irradiation-induced synthesis leads to materials with good crystallinity and tailored morphology, showing promising sorption and recycle properties in dye removal tests. A reaction mechanism is proposed on the basis of LC-MS and FT-IR investigations

    Influence of the composition on the environmental impact of a casting magnesium alloy

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    The influence of the composition of magnesium alloys on their environmental impact was analyzed. In order to perform a more accurate environmental impact calculation, life cycle assessment (LCA) with the ReCiPe 2016 Endpoint and IPCC 2013 GWP (100 y) methodology was used, taking the EcoInvent AZ91 magnesium alloy dataset as reference. This dataset has been updated with the material composition range of several alloys included in the European standard EN 1753:2019. The balanced, maximum, and minimum environmental impact values were obtained. In general, the overall impact of the studied magnesium alloys varied from 3.046 Pt/kg to 4.853 Pt/kg and from 43.439 kg CO2 eq./kg to 55.427 kg CO2 eq./kg, depending on the composition. In the analysis of maximum and minimum environmental impacts, the alloy that had the highest uncertainty was 3.5251, with a range of ±7.20%. The element that contributed the most to increase its impact was silver. The AZ91 alloy, provided by the EcoInvent dataset, had a lower environmental impact than all the magnesium alloys studied in this work. The content of critical raw materials (CRMs) was also assessed, showing a high content in CRMs, between 89.72% and 98.22%

    Polyaniline/TiO2 composites: green photocatalysic synthesis and application in wastewater remediation

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    In recent years, polyaniline (PANI) composites and nanocomposites with metal and metal-oxide materials have received growing attention for electrochemical and photoelectrochemical applications (Gu 2013). Among them, PANI/TiO2 composites are probably the most interesting systems due to synergistic effects between the conductive polymer and the oxide photocatalyst in terms of photogenerated charge separation and photocatalytic efficiency (Bae 2011). Moreover, polyaniline has been reported to possess favourable sorption properties, which can be exploited for pollutant remediation (Alcaraz-Espinoza 2015, Janaki 2012). PANI/TiO2 composites are thus promising candidates for wastewater treatment combining different pollutant remediation approaches. Polyaniline is classically synthesised via oxidative polymerization (Tran 2011), which involves noxious reagents (aniline and peroxydisulfates) and leads to toxic and carcinogenic byproducts (such as benzidine and trans-azobenzidine). In recent years, greener alternatives have been reported, such as a synthetic process starting from aniline dimer ((4-aminophenil)aniline) and using Fe3+ as catalyst and H2O2 as oxidant (Della Pina 2018). Unfortunately, this alternative procedure does not offer any control over the polymer morphology, leading to compact materials with low surface area and, as a consequence, poor dye-sorption capability. Very recently, we proposed a new photocatalytically induced green synthesis leading to stable polyaniline/TiO2 composites with porous morphology, wide surface area, high crystallinity and, most important, excellent dye removal performance and reusability (Cionti 2018). The reaction is carried out in two steps: at first, the aniline dimer is dissolved in a HCl aqueous solution and TiO2 is added while starting UV irradiation. In the second step, H2O2 is added in the dark, leading to the final product. In this work, we shed light on the photocatalytic nature of the synthetic mechanism, highlighting the different roles of TiO2 and of H2O2 on the composite structural and morphological features as well as on the composite performance for pollutant abatement. The reaction mechanism was investigated by a combination of spectrometric techniques, radical scavenger tests, and surface characterizations (Fig.1). By sampling the reaction mixture at different irradiation times, we demonstrated that under UV irradiation the growth of the oligomers occurs at the TiO2 particle surfaces. The same experiment carried out without UV irradiation showed the intrinsic photocatalytic nature of the process: in the dark, only short oligomers without appropriate chain conjugation were produced. However, even after prolonged UV irradiation, the final green product could be obtained only upon addition of H2O2, showing that, while oligomer formation is initiated by radicals produced by TiO2 photocatalysis, small amounts of an oxidant (H2O2) are still needed for the polymer chain growth. The role of the H2O2 amount proved to be especially crucial with respect to the composite properties. Increasing the H2O2 amount together with that of TiO2 led to composites with low surface area and reduced dye removal capability (Fig.2 a) due to a faster polymerization step. On the other hand, when only the photocatalyst amount was increased, neither the product morphology, nor its dye-removal ability were affected. This enables to increase the TiO2 content within the composite with the aim of enhancing its photocatalytic performance. In this respect, the composite stability was tested in water under prolonged UV irradiation, showing that the material optical, structural and morphological properties remained unchanged. The composite was tested towards the removal of anionic azo dyes in aqueous solution, evaluating the effect of the matrix composition and the composite reusability (Fig.2 b), showing promising results

    The influence of environmental conditions on the dimensional stability of components injected with PA6 and PA66

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    The design of assembly components requires special attention to aspects related to their dimensions to ensure their functionality. The goal of this paper is to analyse the influence of case-based environmental conditions, including extreme hydrothermal conditions, on the dimensional stability of a component made from different polyamides throughout the component''s working life. The results support the conclusion that components made from PA6 have a higher capacity to absorb humidity than those made from PA66 and, on the other hand, a higher capacity to lose this humidity, which implies a more significant effect on the average error in the dimensions considered (12% for PA6 in comparison to 3% for PA66). With regard to assembly dimensions, components remain within dimensional tolerances under average and extreme humidity conditions and average temperature conditions. Components injected with P66 are more stable for all of the situations analysed

    The interactions between municipal socioeconomic status and age on hip fracture risk

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    The final publication is available at Springer via http://dx.doi.org/10.1007/s00198-014-2869-0SUMMARY: Age modifies the effect of area-level socioeconomic status (SES) in the risk of fragility hip fractures (HF). For older individuals, the risk of HF increases as SES increases. For younger individuals, risk of HF increases as SES decreases. Our study may help decision-makers to better direct the implementation of political decisions. INTRODUCTION: The effect of socioeconomic status (SES) on hip fracture (HF) incidence remains unclear. The objective of this study is to evaluate the association between HF incidence and municipality-level SES as well as interactions between age and SES. METHODS: From the Portuguese Hospital Discharge Database, we selected hospitalizations (2000-2010) of patients aged 50+, with HF diagnosis (codes 820.x, ICD9-CM), caused by traumas of low/moderate energy, excluding bone cancer cases and readmissions for aftercare. Municipalities were classified according to SES (deprived to affluent) using 2001 Census data. A spatial Bayesian hierarchical regression model (controlling for data heterogeneity and spatial autocorrelation), using the Poisson distribution, was used to quantify the relative risk (RR) of HF, 95% credible interval (95%CrI), and analyze the interaction between age and SES after adjusting for rural conditions. RESULTS: There were 96,905 HF, 77.3% of which were on women who, on average, were older than men (mean age 81.2±8.5 vs 78.2±10.1 years) at admission (p<0.001). In women, there was a lower risk associated with better SES: RR=0.83 (95%CrI 0.65-1.00) for affluent versus deprived. There was an inverse association between SES and HF incidence rate in the youngest and a direct association in the oldest, for both sexes, but significant only between deprived and affluent in older ages (≥75 years). CONCLUSIONS: Interaction between SES and age may be due to inequalities in lifestyles, access to health systems, and preventive actions. These results may help decision-makers to better understand the epidemiology of hip fractures and to better direct the available funding.Programa Operacional Factores de Competitividade (COMPETE)Fundação para a Ciência e a Tecnologia (FCT

    On the differential geometry of curves in Minkowski space

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    We discuss some aspects of the differential geometry of curves in Minkowski space. We establish the Serret-Frenet equations in Minkowski space and use them to give a very simple proof of the fundamental theorem of curves in Minkowski space. We also state and prove two other theorems which represent Minkowskian versions of a very known theorem of the differential geometry of curves in tridimensional Euclidean space. We discuss the general solution for torsionless paths in Minkowki space. We then apply the four-dimensional Serret-Frenet equations to describe the motion of a charged test particle in a constant and uniform electromagnetic field and show how the curvature and the torsions of the four-dimensional path of the particle contain information on the electromagnetic field acting on the particle.Comment: 10 pages. Typeset using REVTE

    Dimensional Stability and Process Capability of an Industrial Component Injected with Recycled Polypropylene

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    The usage of recycled polymers for industrial purposes arises as one of the most promising methods of reducing environmental impact and costs associated with scrapping parts. This paper presents a systematic study of the dimensional stability of a raw and 100% recycled polypropylene subjected to realistic environmental conditions occurring along its working life. The component studied is an internal part of an induction hob assembly. Industrial samples manufactured with both materials, in the same mold, and in the same injection machine, are subjected to ejection conditions, storage conditions (50 °C), and extreme performance conditions (80 °C). Induced dimensional changes are registered and analyzed using a coordinate measuring machine, and a tactile sensing probe. To verify the process capability of the samples manufacturing, Cp and Cpk values are calculated to evaluate the suitability of the recycled material as an alternative. Results conclude that, although the use of recycled material implies slight differences in terms of dimensional stability due to the changes induced in the polymer structure, these differences are not significant enough to affect the injection process capability. Therefore, recycling arises as one effective method to reduce both overruns associated with the consumption of raw polypropylene material and its environmental impact
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