Geochemical study of products associated with spontaneous oxidation of coal in the Cerro Pelado Formation, Venezuela

The aim of this research work is a geochemical, mineralogical, and textural characterization of spontaneously smouldered coal-derived products in northwestern Venezuela (Cerro Pelado Formation, some 10 km from Pedregal city). Several solid samples were collected from this formation, six of unweathering coal, an other six of resulting unmelted rocks forming on a surface coal bed, and the last four of mineralizations found accumulating around gas vents. The fresh coal and the unmelted material were analysed by scanning electron microscopy, X-ray diffraction, and proximate techniques. Products such as magnetite and chabazite-K were identified in the alteration rocks. Likewise, both materials were also studied in order to determine the mobilization of 17 elements into the environment; such elements were analysed through inductively coupled plasma atomic emission spectroscopy on extracts obtained by a sequential extraction method: each sample was firstly extracted with MilliQ water and then the resultant residue was washed. This and the subsequently resulting residues are extracted according to the mentioned procedure by using, respectively, ammonium acetate, chlorhydric acid, peroxide and chlorhydric acid, nitric acid and fluorhydric acid, and nitric acid. The studied elements are classified as highly mobile (Na, Ni, ...), nearly immobile (Ti, P) and partially mobile (Mg, Fe, K,...). In regards to mineralizations around fumaroles associated with smoldering coal seams, Fourier-transform infrared spectroscopy and X-ray diffraction analyses have revealed the presence of salammoniac, mascagnite and other solid combustion compounds formed by reaction of gas emitted from coal oxidation, in addition to previously non-reported sulfur-rich by-products associated with gas fissures, particularly ammonium thiosulfate, a phase first obtained only synthetically in the laboratory. Another objective of the research was to collect and analyse gases escaping from surficial vents. Relatively high concentrations of several aromatic compounds were detected in the gas collected at the studied coal outcrop, as well as aliphatic hydrocarbons including ethane, propane, butanes, among others. High contents of carbon monoxide, methane and carbon dioxide were also measured for gas samples

Influence of a gel emulsion containing microalgal oil and a blackthorn (Prunus spinosa L.) branch extract on the antioxidant capacity and acceptability of reduced fat beef patties

The addition of a blackthorn branch extract (Prunus spinosa L.) to a gel emulsion system containing microalgal oil was examined in order to obtain a functional ingredient (APG), for use as fat replacer in beef patties. Chromatographic analysis indicated that catechins were the major polyphenols present in the Prunus spinosa L. extract. The antioxidant capacity increased as a result of the extract addition, as shown by the comparison of the gel emulsions, with and without it (APG and AG, respectively). Beef patties containing APG as fat replacer (modified patties) had a lower fat content (5.3% versus 10.75%), doubled the antioxidant activity and the DHA content, and improved the stability against oxidation by reducing the peroxide content more than two fold when compared to control patties. In addition, instrumental color measured by the CIE L*a*b* system showed no significant difference between control and modified raw patties. Moreover, the sensory acceptability of the new formulation was confirmed by a like/dislike hedonic test

Phosphogypsum waste lime as a promising substitute of commercial limes : a rheological approach

This paper presents the rheological properties of three types of lime putty, specifying the influence of their origin. The study aims to compare a special lime putty prepared from phosphogypsum with a commercial lime powder and an aged lime putty. The results obtained in terms of chemical composition, crystalline structure, grain size and rheological characterization, (linear viscoelasticity, shear rate and time-dependent flow behaviour) are presented in the study. Putties studied present a similar rheological response, which mainly depends on the particle size and water content. Lower values of the linear viscoelastic functions and viscosity were found for the phosphogypsum lime putty, in agreement with the higher particle size. Transient flow tests reveal a predominant elastic response with no significant shear-induced structural perturbations. However, either a thickening phenomenon over time, i.e. rheopexy, favoured at low shear rates, or a viscosity decrease, i.e. thixotropy, favoured at high shear rates, was observed.The authors would like to thank the aid of CITIUS at the University of Seville for the use of their laboratories for the characterization analyses. A.M.B.-L. has received a Ph.D. Research Grant from the Ministerio de Education, Cultura y Deporte (FPU16/03697)

Age norms for grating acuity and contrast sensitivity in children using eye tracking technology

Key messages: Visual acuity is the most used method to assess visual function in children. Contrast sensitivity complements the information provided for visual acuity, but it is not commonly used in clinical practice. Digital devices are increasingly used as a method to evaluate visual function, due to multiple advantages. Testing with these devices can improve the evaluation of visual development in children from a few months of age. Visual acuity and contrast sensitivity tests, using eye tracking technology, are able to measure visual function in children across a wide range of ages, objectively, quickly and without need of an experienced examiner. Purpose: To report age-normative values for grating visual acuity and contrast sensitivity in healthy children using a digital device with eye tracking technology and to validate the grating acuity test. Methods: In the first project of the study, we examined healthy children aged between 6 months and 7 years with normal ophthalmological assessment. Grating visual acuity (VA) and contrast sensitivity (CS) were assessed using a preferential gaze paradigm with a DIVE (Device for an Integral Visual Examination) assisted with eye tracking technology to provide age norms. For the validation project, we compared LEA grating test (LGT) with DIVE VA in a group of children aged between 6 months and 4 years with normal and abnormal visual development. Results: Fifty-seven children (2.86 ± 1.55 years) were examined with DIVE VA test and 44 successfully completed DIVE CS test (3.06 ± 1.41 years). Both, VA and CS values increased with age, mainly along the first two years of life. Sixty-nine patients (1.34 ± 0.61 years) were included in the DIVE VA test validation. The mean difference between LGT and DIVE VA was − 1.05 ± 4.54 cpd with 95% limits of agreement (LoA) of − 9.95–7.84 cpd. Agreement between the two tests was higher in children younger than 1 year with a mean difference of − 0.19 ± 4.02 cpd. Conclusions: DIVE is an automatic, objective and reliable tool to assess several visual function parameters in children, and it has good agreement with classical VA tests, especially for the first stage of life

Characterization and Analysis of the Carbonation Process of a Lime Mortar Obtained from Phosphogypsum Waste

This work addresses the reuse of waste products as a raw material for lime putties, which are one of the components of mortar. 1:3 Lime/sand mortars very similar to conventional construction mortars were prepared using a lime putty obtained from the treatment of phosphogypsum with sodium hydroxide. The physical, rheological and mechanical properties of this phosphogypsum-derived mortar have been studied, as well as the mineralogical composition, microstructure by scanning electron microscope (SEM) and curing process by monitoring carbonation and ultrasonic propagation velocity. Considering the negative influence of sulphates on the hardened material, the behaviour of the material after sulphates precipitation by adding barium sulphate was additionally tested. Carbonation progressed from the outside to the inside of the specimen through the porous system by Liesegang rings patterns for mortars with soluble sulphates, while the carbonation with precipitated sulphates was controlled by diffusion-precipitation. Overall, the negative influence of low-sulphate contents on the mechanical properties of mortars was verified. It must be highlighted the importance of their precipitation to obtain adequate performance.This research was funded by Programa Estatal I+D+i Retos de la Sociedad of the Ministry of Science and Innovation (Spain), which supported this research (MAT2017-84228-R research project)

New data on the royal Convento of Saint Paulo of Cordoba: the water supply and study of the foundations of its Church

En una reciente actuación arqueológica en el Real Convento de San Pablo de Córdoba hemos podido documentar, de una parte, la cimentación del muro de la fachada principal de la iglesia y, de otra, una importante canalización de agua dulce que abastecía a los dominicos. El monasterio de San Pablo se ubicó en terrenos donados por Fernando III en 1241, concediéndoles el rey un tercio del agua que corría bajo el lienzo este de la muralla de la Villa (antigua Medina).Through a recent archaeological survey at the Royal Monastery of San Pablo in Cordova, we have been able to study the foundations of the wall in the church façade and a freshwater piping system that supplied the dominican friars. The monastery was built on grounds donated by Ferdinand III in 1241, and the king gave the friars access to one third of the water that ran under the east stretch of the wall around the Villa (the old Medina)

Phosphogypsum waste lime as a promising substitute of commercial limes: A rheological approach

This paper presents the rheological properties of three types of lime putty, specifying the influence of their origin. The study aims to compare a special lime putty prepared from phosphogypsum with a commercial lime powder and an aged lime putty. The results obtained in terms of chemical composition, crystalline structure, grain size and rheological characterization, (linear viscoelasticity, shear rate and time-dependent flow behaviour) are presented in the study. Putties studied present a similar rheological response, which mainly depends on the particle size and water content. Lower values of the linear viscoelastic functions and viscosity were found for the phosphogypsum lime putty, in agreement with the higher particle size. Transient flow tests reveal a predominant elastic response with no significant shear-induced structural perturbations. However, either a thickening phenomenon over time, i.e. rheopexy, favoured at low shear rates, or a viscosity decrease, i.e. thixotropy, favoured at high shear rates, was observed

Characterisation model approach for LCA to estimate land use impacts on pollinator abundance and illustrative characterisation factors

This study presents the first approach to characterise relative land use impacts on pollinator abundance for life cycle assessment (LCA). Pollinators make an essential contribution to global crop production and in recent years evidence of declines has raised concerns on how land use, among other factors, affects pollinators. Our novel method assesses land use impacts on pollinator abundance and proposes a new impact category that is compatible with the current framework of life cycle impact assessment (LCIA). While a systematic literature research showed the existence of multiple models that could assess pollinator abundance impacts, their parameterization is too complicated for applications in LCA. Therefore, a simplified method based on expert knowledge is presented. The practical application of the method is illustrated through the connection to, and characterisation of, relevant land use types derived from the widely used LCA database, ecoinvent. The illustrative characterisation factors demonstrate that key differences among land use types can be reflected through the proposed approach. Further development of robust characterisation factors through a larger sample of pollinator abundance estimates, and improvements to the model, such as considerations of spatial differentiation, will contribute to the identification of impacts of agricultural practices in LCA studies, helping prevent further pollinator abundance decline

Some classes of finite groups and mutually permutable products

This paper has been published in Journal of Algebra, 319(8):3343-3351 (2008). Copyright 2008 by Elsevier. http://dx.doi.org/10.1016/j.jalgebra.2007.12.001[EN] This paper is devoted to the study of mutually permutable products of finite groups. A factorised group G=AB is said to be a mutually permutable product of its factors A and B when each factor permutes with every subgroup of the other factor. We prove that mutually permutable products of Y-groups (groups satisfying a converse of Lagrange's theorem) and SC-groups (groups whose chief factors are simple) are SC-groups, by means of a local version. Next we show that the product of pairwise mutually permutable Y-groups is supersoluble. Finally, we give a local version of the result stating that when a mutually permutable product of two groups is a PST-group (that is, a group in which every subnormal subgroup permutes with all Sylow subgroups), then both factors are PST-groups.The second and the fourth authors have been supported by the Grant MTM2004-08219-C02-02 from MEC (Spain) and FEDER (European Union).Asaad, M.; Ballester Bolinches, A.; Beidleman, JC.; Esteban Romero, R. (2008). Some classes of finite groups and mutually permutable products. Journal of Algebra. 8(319). doi:10.1016/j.jalgebra.2007.12.001831