Ammonium concentration in stream sediments resulting from decades of discharge from a wastewater treatment plant

A study of ammonium pollution in the sediments of a stream that receives wastewater treatment plant (WWTP) discharge has been carried out. It is urgently necessary to find environmental indicators that can help prevent and detect potential contamination of water, as water is an increasingly scarce resource. To understand the behaviour of ammonium ions introduced by a historical (50-year) contamination process, vertical boreholes were drilled in the stream banks to depths between 30 and 120 cm. Moisture, pH, ammonium (soluble and exchangeable), and clay fraction content were analysed. The variation profile of these parameters was evaluated as a function of depth to determine factors related to the distribution of ammonium in several locations along the stream banks. The ammonium concentration was asymmetrically distributed among samples collected in near-surface locations, with ammonium concentrations between 0.3048 mmol/kg soil and 0.0007 mmol/kg soil. Ammonium was typically concentrated at sediment depths of 30–40 cm, which also exhibited the highest clay fraction content. High positive correlations were detected (r > 0.8; p < 0.0001) among the different ammonium variables (exchanged and dissolved species). No contamination effect was observed below 60–70 cm depth, which was due to ammonium retention in a natural barrier layer of clayey sediment. The clays in our study area (previously identified as smectite, a 2:1 sheet silicate) were able to control the contamination by retaining ammonium in the interlayers, which retarded nitrification. It is suggested that clay could serve as a geo-indicator of ammonium pollution evolutio

Characterization of the Miocene deposits of the Nueva Tabarca island (Alicante) and their use as building material in the local built heritage

El presente trabajo muestra la caracterización en detalle de la secuencia estratigráfica de los depósitos miocenos de la isla de Nueva Tabarca, el empleo de estos materiales en el patrimonio arquitectónico de la isla y su comportamiento frente la degradación. En la serie miocena, a grandes rasgos, se definen tres tramos. El tramo inferior, rico en clastos dolomíticos, muestra una alternancia de arenitas y calcarenitas. El tramo intermedio corresponde a una sucesión de niveles de calcirruditas con laminación cruzada cuya parte superior está representada por un nivel de grandes bioclastos, rodolitos y arenitas de grano fino. El comienzo del último tramo está marcado por la presencia de varias superficies arenosas más litificadas sobre las que se sitúa un banco de arenitas de grano fino y laminación paralela. Si bien las canteras extraían sillares de todas estas litofacies, existe una mayor extracción de los últimos niveles de la serie. Estas rocas presentan una durabilidad moderada-baja, degradándose fácilmente mediante arenización, escamación y/o alveolización.The aims of the present work are: i) the description of the Miocene deposits cropping out in the Nueva Tabarca island; ii) the characterization of the use of these rocks in the local heritage; and iii) the analysis of the rock behavior during weathering processes. The Miocene stratigraphic succession can be divided into three parts. The first one shows dolomite-rich sandstones interbedded to biocalcarenites rich in corals, red algae, thick-shelled bivalves and clypeasteroids. The second part corresponds to cross-laminated calcirudites whose top is represented by a condensed level rich in large bioclasts and rhodolites, passing upward to fine-grained sandstones. The third part begins with several hardened levels of sandstones followed by fine-grained parallel-laminated sandstones. Ancient quarries were located at every level of the stratigraphic series. Consequently, every lithofacies are observed in the current ashlars of the monuments. These rocks are easily decayed by means of granular disintegration, flakes and/or alveolar weathering.Este trabajo se ha realizado en el marco del Proyecto GRE13-23 (Investigaciones Emergentes del Programa Propio de la Universidad de Alicante)

Inland Record of the Last Interglacial Maximum in the Western Mediterranean: Revealing the Aljezares Pleistocene Basin (Alicante, SE-Spain)

The search for a continuous continental record of interglacial periods in semi-arid regions is problematic due to the absence of stable and continuous sedimentary systems over time in this type of climate. In this work, a relatively stable basin is described and analyzed during the last interglacial period in a semi-arid region of the western Mediterranean. For this purpose, a geomorphological, stratigraphic and sedimentological study has been carried out, with dating through 230Th. A semi-endorheic Pleistocene section has been identified, with two units that correspond to a fluvial-lacustrine system (unit P1) and an alluvial system (unit P2). Unit P1 has been dated to the MIS 5e interglacial episode. A framework for future studies is described, in which the Aljezares Pleistocene basin can be considered as a possible source of paleoenvironmental and paleoclimatic information in semi-arid regions from the last interglacial period.The research has been funded through the following Spanish research projects: I+D+i PID2021-122308NA-I00 (NESUBSTRA-UV) and I+D+i PID2021-123510OB-I00 (QTECTIBERIA-USAL) by the MICIN

Synthesis of EDTA core dendrimers through a consecutive esterification-CuAAC process

Artículo para obtención de grado de DoctorA novel class of thermostable G0 and G1-dendrimers was synthesized from the coupling of both propargyl and azido esters derived from EDTA through copper catalyzed azide-alkyne cycloaddition. The branching and size in these compounds were controlled by a simple azide-alkyne group position change in the CuAAC reaction in conjunction with the use of 1,3-diazido-propan-2-ol as a polyfunctional compound

SEM-EDX study of bentonite alteration under the influence of cement alkaline solutions

Bentonite is a key barrier for the isolation of high-level radioactive waste within Deep Geological Repository. However, bentonite may be altered by contact with cementitious materials and their alkaline pore fluids. This study offers an extensive morphological and semi-quantitative characterization of the bentonite surface exposed to three types of alkaline pore fluids released by different cement-based materials. The bentonite surfaces were studied using a thorough scanning electron microscopy exploration and analysed using an energy-dispersive ꭕ-ray detector (SEM-EDX). In addition, statistical, element mappings, ꭕ-ray diffraction and infrared spectroscopy analyses were performed. The aim was to have a picture of the morphological and chemical alterations of bentonite at very early stages in accordance with the integrated approach necessary to address bentonite stability in the long-term. As a consequence of the reactivity, two types of morphologies stood out in the matrix of bentonite: platelets and coatings-like crusts characterized by their high Mg and Ca content. These alterations presented a different scope depending on the type of alkaline pore solution involved and suggested the precipitation of authigenic magnesium silicate hydrates (M-S-H) and/or trioctahedral clay minerals and Ca‑carbonates. The knowledge of the performance of bentonite subjected to these alkaline solutions can help in the evaluation of the most suitable cement-based materials to be used next to bentoniteThe experimental work was supported by funding from the European Union‘s Horizon 2020 Research and Training programme from EURATOM [H2020-NFRP 2014, 2015] under grant agreement n◦662147; CEBAM

Caracterización petrográfica y petrofísica de la roca encajante de la Cueva del Rull (Vall d'Ebo, Alicante)

La Cueva del Rull se encuentra en el sector nororiental de la Cordillera Bética, en el denominado Prebético Externo de Alicante (Azema 1977). Regionalmente, la zona de estudio está dominada por la dinámica compresiva de los materiales calizos existentes (Cretácico Superior) afectados, desde el Mioceno Medio y durante el Mioceno Superior, por diversos movimientos tectónicos a partir de los cuales se origina la Depresión de la Vall d'Ebo. Esta fosa tectónica, cuyos bordes norte y sur quedan delimitados por fallas normales con dirección aproximada E-O, está rellena por materiales rudíticos de edad Mioceno Superior, predominantemente conglomeráticos, de espesor variable (decenas a más de 100 metros), localmente plegados y depositados sobre margas de facies “tap” (margas mal estratificadas de carácter arcillo-limoso, desagregadas y de color blanquecino en superficie, cuya edad se atribuye al Mioceno Medio).Este trabajo ha sido financiado por el proyecto CGL2011-25162 del Ministerio de Economía y Competitividad. C. Pla cuenta con una beca predoctoral del MEC correspondiente a dicho Proyecto

PLATAFORMAS PARA CONTROLADOR ACTIVO LINEAL APLICADO A LA DIRECCIÓN ASISTIDA AUTOMOTRIZ (PLATFORMS FOR LINEAR ACTIVE CONTROLLER APPLIED TO THE AUTOMOTIVE ASSISTED STEERING)

En este artículo se muestra un problema clásico en la teoría de control, el cual es el diseño de una ley de retroalimentación, teniendo el propósito de que la salida de cualquier sistema siga asintóticamente una señal de referencia. En este trabajo, se pretende que la velocidad lateral siga a una maniobra del conductor, pero en sentido contrario. Se propone que el vehículo se encuentra realizando pruebas de manejo conocidas por norma internacional ISO 7401, por ende el problema de la teoría de regulación lineal vía retroalimentación de estados por medio de una función de Lyapunov es la solución idónea a nuestro problema ya que se supone la medición de la velocidad angular de viraje. Los actuadores que integraremos en este artículo serán los frenos () y el sistema frontal activo (AFS, por sus siglas en inglés), por medio de la simulación de Matlab-Simulink-CarSim y una plataforma propia.Palabra(s) clave: Retroalimentación de estados, velocidad lateral, velocidad angular de viraje, CarSim. AbstractThis article shows a classic problem of control theory, which is the design of a feedback law, it has the purpose that the output of any system follows a reference signal asymptotically. In this paper we aim that the lateral velocity follows a drivers´s maneuver, but in the opposite direction. It is proposed that the vehicle performs driving test knowed by the ISO 7401 international standard, thus, to solve this problem we are going to use the feedback-state lineal theory by means of a Lyapunov function, because it is supposed to measure the yaw velocity. The actuators that we will be integrating in this paper, will be the brakes () and Front Active System (AFS), through simulations in Matlab- Simulink-CarSim and own platform.Keywords: Feedback state, lateral velocity, yaw velocity, CarSim

Impact of a tire fire accident on soil pollution and the use of clay minerals as natural geo-indicators

Following the occurrence of a fire at a tire landfill in the surrounding area of Madrid City (Spain), polycyclic aromatic hydrocarbons (PAHs) and trace elements present in soils were analyzed to assess the impact of the fire. The capacity of the soils’ clay mineral fraction to reflect this air pollution incident was studied. Fourteen soil samples were collected at different distances under the smoke plume, and they were subjected to high-performance liquid chromatography–photodiode array detection, inductively coupled plasma mass spectrometry and X-ray diffraction analyses. Clay minerals content showed a strong correlation with the pollutants potentially released in the tire fire, acenaphthene, pyrene, benzo(a)pyrene and benzo(a)fluoranthene. Trace metals Zn and Se were related to the proximity of the tire fire without any relationship with clay minerals content. This work suggests the use of natural clay minerals as potential PAHs geo-indicators in response to air pollution, complementary to current air and biological analysesThis work has been economically supported by the Ministry of Economy and Competitiveness of Spain, Project AGL2016-78490-