Photoactivation and photoregeneration of TiO2/PAC mixture applied in suspension in water treatments: approach to a real application

Environmental Science and Pollution Research - The process TiO2/PAC/UV-vis has been under study and compared with the isolated treatments of adsorption and photocatalysis determining possible...     

Predictive models of turbidity and water depth in the Doñana marshes using Landsat TM and ETM+ images

We have used Landsat-5 TM and Landsat-7 ETM+ images together with simultaneous ground-truth data at sample points in the Doñana marshes to predict water turbidity and depth from band reflectance using Generalized Additive Models. We have point samples for 12 different dates simultaneous with 7 Landsat-5 and 5 Landsat-7 overpasses. The best model for water turbidity in the marsh explained 38% of variance in ground-truth data and included as predictors band 3 (630–690 nm), band 5 (1550–1750 nm) and the ratio between bands 1 (450–520 nm) and 4 (760–900 nm). Water turbidity is easier to predict for water bodies like the Guadalquivir River and artificial ponds that are deep and not affected by bottom soil reflectance and aquatic vegetation. For the latter, a simple model using band 3 reflectance explains 78.6% of the variance. Water depth is easier to predict than turbidity. The best model for water depth in the marsh explains 78% of the variance and includes as predictors band 1, band 5, the ratio between band 2 (520–600 nm) and band 4, and bottom soil reflectance in band 4 in September, when the marsh is dry. The water turbidity and water depth models have been developed in order to reconstruct historical changes in Doñana wetlands during the last 30 years using the Landsat satellite images time series.     

Modelling remediation scenarios in historical mining catchments

Local remediation measures, particularly those undertaken in historical mining areas, can often be ineffective or even deleterious because erosion and sedimentation processes operate at spatial scales beyond those typically used in point-source remediation. Based on realistic simulations of a hybrid landscape evolution model combined with stochastic rainfall generation, we demonstrate that similar remediation strategies may result in differing effects across three contrasting European catchments depending on their topographic and hydrologic regimes. Based on these results, we propose a conceptual model of catchment-scale remediation effectiveness based on three basic catchment characteristics: the degree of contaminant source coupling, the ratio of contaminated to non-contaminated sediment delivery, and the frequency of sediment transport events.     

Use of recycled fine aggregate in concretes with durable requirements

The use of construction waste materials as aggregates for concrete production is highly attractive compared to the use of non-renewable natural resources, promoting environmental protection and allowing the development of a new raw material. Several countries have recommendations for the use of recycled coarse aggregate in structural concrete, whereas the use of the fine fraction is limited because it may produce significant changes in some properties of concrete. However, during the last decade the use of recycled fine aggregates (RFA) has achieved a great international interest, mainly because of economic implications related to the shortage of natural sands suitable for the production of concrete, besides to allow an integral use of this type of waste. In this study, the durable behaviour of structural concretes made with different percentage of RFA (0%, 20%, and 30%) is evaluated. Different properties related to the durability of concretes such as absorption, sorptivity, water penetration under pressure, and carbonation are determined. In addition, the results of compressive strength, static modulus of elasticity and drying shrinkage are presented. The obtained results indicate that the recycled concretes have a suitable resistant and durable behaviour, according to the limits indicated by different international codes for structural concrete.     

A new simple methodology for evaluation of explosion risk in underground coal mines

The key objective of this paper is the presentation of a new risk assessment tool for underground coal mines based on a simplified semi-quantitative estimation and assessment method.In order to determine the risk of explosion of any work process or activity in underground coal mines it is necessary to assess the risk. The proposed method is based on a Risk Index obtained as a product of three factors: frequency of each individual scenario P_ucm, associated severity consequences C_ucm and exposure time to explosive atmospheres E_ucm. The influence of exposure time is usually not taken into account up to now. Moreover, the exposure to explosive atmospheres may affect factors of hazardous event probability as much as its consequences. There are many definitions of exposure to explosive atmospheres but in the case of underground coal mines the exposure is defined as frequency risk of firedamp and coal dust. The risk estimation and risk assessment are based on the developed of a risk matrix.The proposed methodology allows not only the estimation of the explosion risk but also gives an approach to decide if the proposal investment is well-justified or not in order to improve safety.     

Optimization of the recovery of plastics for recycling by density media separation cyclones

Material recovery processes are presented as the optimum option for recycling plastic wastes as a means of recovering hydrocarbon resources. There exist a large variety of automated material recovery processes for recycling of such wastes but each with significant limitations. Of these, the separation based on differences in densities is advocated as the optimum process either for producing recycled products or preparing wastes for subsequent recovery processing.Density separation processes based on cyclone type density media separation (DMS) is presented as an important, potential method for increasing plastics recycling process capacities. It is demonstrated to have the capacity to separate a significantly larger range of particle sizes than those presently processed industrially. The mathematical relationship for the prediction of quality of typical LARCODEMS type density media separations by particle size and density as expressed by the Ecart Probable is presented.A proposed device configuration is presented for density media separation to optimize the recovery and purity of both density fractions produced. It is also suggested that to be economically viable, a large scale of operation is required for industrial plastics recycling operations recovering and producing a number of different plastics with a purity to be used as a substitute for virgin material.     

Total and Methylmercury in Soft Tissues of White-Tailed Eagle (Haliaeetus albicilla) and Osprey (Pandion haliaetus) Collected in Poland

Mercury (Hg) contamination in piscivorous birds, especially methylmercury (MeHg), has been drawing much attention worldwide in regard to its bioaccumulation and biomagnification in food chains. In this study on Hg in the soft tissues of white-tailed eagles (n = 22) and ospreys (n = 2) from Poland, total Hg (THg) range was 0.15–47.6 while MeHg range was 0.11–8.05 mg kg⁻¹ dry weight. In both species, median THg and MeHg concentrations were lower in the muscle and brain than in the liver and kidney. Median nephric residues were just under 3 and 5 mgTHg kg⁻¹ or 0.9 and 3.7 mgMeHg kg⁻¹ for white-tailed eagle and osprey, respectively. In Norwegian data from the 1970s and in our results, MeHg in the muscle of white-tailed eagle was ~60 % THg (%MeHg = MeHg/THg × 100), lower than in other piscivorous birds. A clear similarity in THg tissue levels was found between Polish and German populations of white-tailed eagles.     

Improved weighted ensemble learning for predicting the daily reference evapotranspiration under the semi-arid climate conditions

Environmental Science and Pollution Research - Evapotranspiration is an important quantity required in many applications, such as hydrology and agricultural and irrigation planning. Reference...     

The fractal dimension of a conspicuous ornament varies with mating status and shows assortative mating in wild red-legged partridges (<Emphasis Type="Italic">Alectoris rufa</Emphasis>)

Complex body designs, such as plumage ornaments in birds, can be described by fractal geometry. These complex patterns could have a role as visual signals during courtship and social interactions, but an empirical validation in the wild is currently lacking. Here, we investigated whether the fractal dimension (FD) of a complex plumage pattern displayed by red-legged partridges Alectoris rufa could function as a potential sexual signal. We captured wild birds early in the breeding season and tested if mated and unmated birds differed in the FD of their conspicuous melanin-based black bib. We also tested if the FD of the black bib was correlated within the pair, looking for evidence of assortative mating based on the expression of this trait. We simultaneously assessed similar effects in other ornamental traits (black bib size, white throat patch and black flank band surface, redness of the eye rings and bill). Mated birds showed higher black bib FD values than unmated ones. Mated males, but not females, also displayed a larger black bib. Moreover, the black bib FD (but not the trait size) and the white throat patch surface showed assortative mating. Finally, females with higher black bib FD showed smaller black flank band surface, suggesting a trade-off in the expression of the two melanin-pigmented plumage traits. This provides unique and novel indication for the shape complexity of a pigmented trait, here described by its fractal dimension, to be potentially under sexual selection in a wild animal.