Mn mining wastes as an industrial income for concrete production: inventory of waste dumps and resources estimation in the Iberian Pyrite Belt, SW Spain

The present work aims to evaluate the possibility of achieving an environmental and economic valorisation of Mn-wastes through their recycling for concrete production. The study area is located in the Spanish sector of the Iberian Pyrite Belt (IPB), where there are numerous abandoned mine-waste dumps, resulted from exploitation of manganese mines. The methodological approach included field surveys for elaborating an inventory and a general map of all the abandoned exploitations, remote sensing methods for identifying old mines and for estimation of affected areas; and laboratory analyses for characterizing the mine wastes regarding evaluation of their potential as filler for concrete production. The obtained results indicated the existence of 149 mines, representing a total affected area of 235 ha. Among these waste dumps, about eleven of them have more than 10 000 m3 of Mn-gangue with chemical composition compatible with the normative for concrete production. The recycling of such wastes may accomplish two main purposes: to supply the market with low cost aggregates and, simultaneously, to contribute for the environmental rehabilitation of the affected areas.info:eu-repo/semantics/publishedVersio

Experimental analysis of slabs foundation by scale models: lightweight slabs by expanded polystyrene blocks opposite solid slabs

El objetivo del presente artículo es confirmar el distinto comportamiento que presenta la solución tradicional de losa maciza frente a una aligerada, empleando bloques de poliestireno expandido (EPS) como material aligerante, uniéndose las zonas macizas bajo pilares mediante nervios. Se mantienen por tanto, dos placas, superior e inferior, alrededor de los bloques aligerantes de EPS. Para ello se ha realizado dos modelos a escala, sometiendo cada uno de ellos a una serie de ensayos. Esto se ha podido analizar comparativamente con otros modelos hechos en ordenador, empleando para ello programas de Elementos Finitos. Los resultados obtenidos permiten afirmar que, en situaciones de suelos blandos, con posibles problemas de asientos, la solución planteada presenta importantes ventajas, al disminuir esos asientos en un porcentaje que variará en función de las condiciones particulares. Además de esto, se reducen en gran medida los asientos diferenciales entre apoyos, por lo que la alternativa planteada presenta un comportamiento más uniforme, así como ventajas constructivas.The aim of this work is to confirm the different behavior of traditional solid slab versus lightened solution, using expanded polystyrene (EPS) blocks as a lightening material, joining solid areas under pillars with grating beams. Therefore there are two plates, one of them on the top and the other one on the bottom, covering the EPS blocks. For this purpose, two scale models have been performed, each of them being subjected to a series of tests. These have been able to comparatively analyze with models made in computer, using Finite Element programs. The results obtained allow us to assert that in situations of soft soils, with possible problems of settlements, the proposed solution has significant advantages by reducing this settlement on a percentage it will vary depending on specific conditions. Besides this, it significantly reduces the differential settlements among supports, so this alternative has a more uniform behavior, as well as constructive advantages

Salt efflorescences in the iberian pyrite belt: occurrence and distribution

The evolution of sulfide wastes promotes acid mine drainage and phenomena of supergenic neoformation. These contribute to a secondary paragenesis, often dominated by salt efflorescences. These can be used as mineralogical indicators of reactivity conditions and of AMD potential. The present study shows the salt efflorescences that develop in the Spanish sector of the Iberian Pyrite Belt, as a result of the strong acid mine drainage observed in this region. The obtained results showed dominance of metallic sulfates. Depending on the proximity to the sulfide sources, there are different types of assemblages. Iron and cooper minerals dominate inside the mining areas, whereas magnesium sulfates occur more abundantly in the receiving river networkFinancial support was provided by the Andalusian Autonomous Government Excellence Project, code P06-RNM-02167. This work was also co-funded by the European Union through the European Regional Development Fund, based on COMPETE 2020 (Programa Operacional da Competitividade e Internacionalização), project ICT (UID/GEO/04683/2013) with reference POCI-01-0145-FEDER- 007690 and national funds provided by Fundação para a Ciência e Tecnologia.info:eu-repo/semantics/publishedVersio

Eye movements as a predictor of preference for progressive power lenses

The purpose of this study is to determine if there is any correlation between the characteristics of the user’s eye movements (EMs) and the preference of the user when wearing different Progressive power lenses (PPLs) distributions. An eye-tracker system with a sample rate of 120Hz and temporal resolution of 8.3ms (Tobii-X3-120) was used to register EMs of 38 PPL users when reading in a computer screen with 2 types of PPLs (PPL-soft and PPL-hard). Number of fixations, complete fixation time, fixation duration mean, saccade duration mean, saccade distance mean, and number of regressions were analyzed for 6 different regions of the computer screen. A statistically significant difference was observed between the characteristics of the user’s EMs and the user’s PPL subjective preference (p<0.05*). Subjects that preferred the PPL-hard presented significantly lower complete fixation time, lower fixation duration mean and lower number of regressions than those subjects indicating a preference for the PPL-soft. Results of this study suggest that eye-tracking systems can be used as PPL design recommendation systems according to the user EMs performance

Exercise prior to influenza vaccination for limiting influenza incidence and its related complications in adults

Influenza is an infectious virus affecting both humans and animals. In humans, symptoms present as fever, cough, sore throat, runny nose, headache, muscle and joint pain, and malaise. The epidemiological profile of influenza is influenced by multiple factors, including transmissibility of the virus and the susceptibility of the population. Annually, influenza is estimated to infect 5% to 10% of adults, with higher rates in winter seasons in countries with seasonal variation. Exercise could be an intervention to enhance immune response and limit influenza incidence and its related complications.To assess the efficacy and safety of short and long-term exercise prior to influenza vaccination in enhancing influenza prevention in adults.We searched CENTRAL (2015, Issue 11), which contains the Cochrane Acute Respiratory Infections Group's Specialised Register, MEDLINE (1966 to 3 November 2015), Embase (1974 to 3 November 2015), CINAHL (1981 to 3 November 2015), LILACS (Latin American and Caribbean Health Sciences, 1982 to 3 November 2015), PEDro (1980 to 3 November 2015), SPORTDiscus (1985 to 3 November 2015), the WHO International Clinical Trials Registry Platform (ICTRP) and ClinicalTrials.gov (November 2015).Randomised controlled trials (RCTs) of short- and long-term exercise prior to influenza vaccination for the general adult population were eligible for inclusion.Two review authors independently extracted and checked data from the included trials using a standard form. We used the random-effects model due to differences in the type, duration, intensity and frequency of exercise in the analysis.We included six trials published between 2007 and 2014 that randomised 599 adult participants. Study size ranged from 46 to 158 participants. Participants were aged between 18 years and 80 years; we could not derive gender proportions, as participants' sex was not reported in all studies. One study was available in abstract form only.We did not find a significant difference in outcomes between people who exercised and those who did not exercise before receiving influenza vaccination.Pre-vaccination exercises included endurance activities such as walking or using a treadmill, and resistance activities included biceps curls and lateral raises. Five of the studies provided one session of exercise between 25 and 50 minutes. In five studies, exercise was undertaken on the same day as the vaccination. One study provided exercise over a period of eight weeks before vaccination, with one 2½ hour supervised session, plus daily home exercise practice of 45 minutes. Exercise intensity ranged from 55% to 85% of maximal heart rate. Control group participants undertook a range of activities, including quiet rest, sitting, reading, meditation or unspecified activity.One study reported numbers of people who contracted influenza; no significant difference was reported between exercise and no-exercise participants. None of the included studies reported complications related to influenza illness. Only one study, which we assessed as providing low-quality evidence, reported numbers of people who experienced adverse events. This study reported no significant difference in outcomes between people who exercised and those who did not. No studies reported numbers of working days or days lost related to influenza illness. Only two studies reported participant-centred outcomes.Overall, study quality was unclear; we assessed five of the six included studies to have at least four unclear 'Risk of bias' domains (allocation concealment, blinding of outcome assessment, selective reporting and other bias). Insufficient reporting in four studies about selective reporting did not provide enough information to enable judgement; only two studies were included in trials registers.From the available evidence, we found that exercising before influenza vaccination is neither beneficial nor harmful. However, study data were limited and of low quality. Small sample sizes, study design limitations, exercise types, and focus on biochemical rather than participant-centred outcomes strongly influenced our findings

Caracterización hidrogeoquímica de efluentes de escombreras en el grupo minero la Zarza-Perruna

info:eu-repo/semantics/publishedVersio

Estudio hidroquímico de los embalses afectados por procesos de drenaje ácido de mina en la faja pirítica ibérica

info:eu-repo/semantics/publishedVersio

Are Cu isotopes a useful tool to trace metal sources and processes in acid mine drainage (AMD) context?

In the South-West Europe (Iberian Pyrite Belt), acid mine drainage (AMD) processes are especially problematic because they affect the environmental quality of watersheds, restricting the use of surface water. Recent studies have shown that Cu isotopes are fractionated during the oxidative dissolution of primary sulfide minerals and could be used to trace metal cycling. However the chemistry of Cu in such environment is complex because Cu is redistributed within numerous secondary minerals and strongly dependent on the hydroclimatic conditions that control key parameters (pH, redox conditions). Finally, it remains difficult to compare the various field studies and deliver some strong general tendencies because of these changing conditions. For these reasons, concerted studies on Cu isotopes fractionation in waters impacted by AMD may help to reveal the sources and transport pathways of this important pollutant. To address this issue, we used a representative scenario of strong contamination by AMD in the Iberian Pyrite Belt (SW Spain), the Cobica River. The aim of our study is to measure the Cu isotopes signature in the waters (river, mine lake, water draining waste) of the small Cobica River system (Huelva, Spain), sampled during a short period (8 h) to avoid any change in the hydro-climatic conditions. This provided an instantaneous image of the isotopic Cu signature in a small mining systems and helped us to constrain both the processes affecting Cu isotopes and their use a potential tracer of metals in contaminated environments.This work was supported by the french national programme EC2CO Biohefect/Ecodyn//Dril/MicrobiEen (INSU/CNRS, France), the Paul Sabatier University (France) and the Department of Mining, Mechanical, Energetic and Construction Engineering of the University of Huelva (Spain)

Unveiling the hidden entropy in ZnFe_2O_4

The antiferromagnetic (AFM) transition of the normal ZnFe_2O_4 has been intensively investigated with results showing a lack of long-range order, spin frustrations, and a "hidden" entropy in the calorimetric properties for inversion degrees delta approximate to 0 or delta = 0. As delta drastically impacts the magnetic properties, it is logical to question how a delta value slightly different from zero can affect the magnetic properties. In this work, (Zn_(1-delta)Fe_delta)[Zn_delta Fe_(2-delta)]O_4 with delta = 0.05 and delta = 0.27 have been investigated with calorimetry at different applied fields. It is shown that a delta value as small as 0.05 may affect 40% of the unit cells, which become locally ferrimagnetic (FiM) and coexists with AFM and spin disordered regions. The spin disorder disappears under an applied field of 1 T. Mossbauer spectroscopy confirms the presence of a volume fraction with a low hyperfine field that can be ascribed to these spin disordered regions. The volume fractions of the three magnetic phases estimated from entropy and hyperfine measurements are roughly coincident and correspond to approximately 1/3 for each of them. The "hidden" entropy is the zero point entropy different from 0. Consequently, the so-called "hidden" entropy can be ascribed to the frustrations of the spins at the interphase between the AFM-FiM phases due to having delta approximate to 0 instead of ideal delta = 0