Search results for "Roca"
showing 10 items of 1893 documents
El archivo fotográfico de la Fundación de los Ferrocarriles Españoles
2014
Este texto realiza un breve recorrido por la fotohistoria ferroviaria para, a continuación, centrarse en los fondos y colecciones que atesora el Archivo Histórico Ferroviario del Museo del Ferrocarril de Madrid, entidad integrada en la Fundación de los Ferrocarriles Españoles (FFE), donde las fuentes fotográficas complementan el ingente legado histórico ferroviario conservado en todas sus dimensiones. Las fuentes gráficas juegan un papel fundamental en la investigación histórica, ofrecen un universo excepcional desde diferentes líneas, enfoques o puntos de vista heterogéneos, aunque no necesariamente divergentes.
Risk assessment of exposure to organic chemicals in children and mothers using human biomonitoring
2022
Today, global chemical manufacturing is increasing each year, making environmental pollution and exposure to chemicals a serious public health problem linked to the development of many non-genetic diseases. Approximately, 70 % of chemicals consumed in Europe in 2019 were hazardous for human health. These harmful substances can enter to the food chain and remain in the environment, making humans exposed to them mainly by ingestion, inhalation or dermal exposure. Consequently, exposure to chemicals should be continuously monitored for assuring health protection of citizens by two ways: i) studying their presence in environmental compartments, such as water, food, soil or air, by environmental…
Patrones estructurales y funcionales de las comunidades de procariotas en humedales mediterráneos y su relación con el ciclo del carbono
2023
Las zonas húmedas mediterráneas juegan un papel muy importante en los ciclos biogeoquímicos, ya que la presencia de agua, de forma constante o transitoria, favorece unas altas tasas metabólicas. Respecto al ciclo del carbono, los humedales mediterráneos se ven activamente involucrados en la captación o en la emisión de gases de efecto invernadero carbonados (C-GEI) hacia la atmósfera, concretamente el dióxido de carbono y el metano. Esta relevancia de los humedales en el ciclo del carbono se debe, en parte, a la actividad de las comunidades de procariotas que habitan en el agua y en el sedimento de las zonas húmedas, puesto que la abundancia y versatilidad metabólica de los procariotas les …
Aqueous-phase reactive species formed by fine particulate matter from remote forests and polluted urban air
2021
In the aqueous phase, fine particulate matter can form reactive species (RS) that influence the aging, properties, and health effects of atmospheric aerosols. In this study, we explore the RS yields of aerosol samples from a remote forest (Hyytiälä, Finland) and polluted urban locations (Mainz, Germany; Beijing, China), and we relate the RS yields to different chemical constituents and reaction mechanisms. Ultra-high-resolution mass spectrometry was used to characterize organic aerosol composition, electron paramagnetic resonance (EPR) spectroscopy with a spin-trapping technique was applied to determine the concentrations of ⚫OH, O2⚫-, and carbon- or oxygen-centered organic radicals, and a …
The formation, properties and impact of secondary organic aerosol: Current and emerging issues
2009
Hallquist, M. Wenger, J. C. Baltensperger, U. Rudich, Y. Simpson, D. Claeys, M. Dommen, J. Donahue, N. M. George, C. Goldstein, A. H. Hamilton, J. F. Herrmann, H. Hoffmann, T. Iinuma, Y. Jang, M. Jenkin, M. E. Jimenez, J. L. Kiendler-Scharr, A. Maenhaut, W. McFiggans, G. Mentel, Th. F. Monod, A. Prevot, A. S. H. Seinfeld, J. H. Surratt, J. D. Szmigielski, R. Wildt, J.; Secondary organic aerosol (SOA) accounts for a significant fraction of ambient tropospheric aerosol and a detailed knowledge of the formation, properties and transformation of SOA is therefore required to evaluate its impact on atmospheric processes, climate and human health. The chemical and physical processes associated wit…
Blue biotechnology: oil bioremediation using hydrocarbon-degrading bacteria immobilized on biodegradable membranes
2017
A novel bioremediation system to clean up oil contaminated water was developed combining hydrocarbon (HC) degrading bacteria immobilized and polylactic acid (PLA) or polycaprolactone (PCL) membranes prepared by electrospinning. The bioremediation efficiency was tested on crude oil using highly performant HC degrading bacterial strains isolated from marine and soil environments. The membrane morphology, the microbial adhesion and proliferation were evaluated using scanning electron microscopy (SEM). The SEM analysis highlighted that the fibers of the electrospun mats were in nanoscale with a similar diameter size distribution. The electrospun membranes exhibited high oil absorption capacity …
HYDROCARBONS REMOVAL FROM BILGE WATER BY ADSORPTION ONTO ACTIVATED BIOCHAR FROM POSIDONIA OCEANICA
2019
The normal operations carried out on the boats during navigation generate waste waters such as oily bilge water. The latter is the aqueous mixture of potential pollutants of different origins and types: oily fluids, lubricants and greases, cleaning fluids and other wastes that accumulate in the lower part of the vessel [1,2]. The current legislation provides that they can be discharge directly into the sea if the concentrations of some components are below the expected limits. In particular, with regard to oil / hydrocarbons contamination, the current regulatory limit is 15 mg L-1 of total hydrocarbons. The present work starts from a public/private partnership funded by a grant of the Minis…
Selective recognition of aromatic hydrocarbons by endo-functionalized molecular tubes via C/N-H⋅⋅⋅π interactions
2018
Molecular recognition of aromatic hydrocarbons by four endo-functionalized molecular tubes has been studied by 1H NMR spectroscopy, computational methods, and single crystal X-ray crystallography. The binding selectivity is rationalized by invoking shape complementarity and dipole alignment. The non-covalent interactions are proved to predominantly be C/N-H⋅⋅⋅π interactions. peerReviewed
Highly Active and Stable NiCuMo Electrocatalyst Supported on 304 Stainless Steel Porous Transport Layer for Hydrogen Evolution in Alkaline Water Elec…
2023
Several functionalized porous transport layers with Pt-free electrocatalysts for hydrogen evolution reaction in alkaline conditions, based on Ni, Cu, and Mo, are prepared through electrodeposition onto a 304 stainless steel mesh. Morphological characterization confirms the fabrication of electrodes with high electrochemical surface active area due to the formation of hierarchical nanostructures. Mo presence into the electrocatalysts increases the activity toward the hydrogen evolution reaction. The optimization of electrodeposition process leads to the preparation of highly active NiCuMo electrocatalyst that exhibits near zero onset overpotential and overpotentials of 15 and 113 mV at 10 an…
Coincidence and common fixed points of weakly reciprocally continuous and compatible hybrid mappings via an implicit relation and an application
2015
Using the hybrid version of the notion of weakly reciprocal continuous mappings due to Gairola et al. [Coincidence and fixed point for weakly reciprocally continuous single-valued and multi-valued maps, Demonstratio Math. (2013/2014), accepted], we prove a coincidence and common fixed point theorem for a hybrid pair of compatible mappings via an implicit relation. Our main result improves and generalizes a host of previously known theorems. As an application, we give a homotopy theorem which supports our main result.