Articles publicats (Química, Física i Ciències Ambientals i del Sòl)

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    Open Access
    Ammonia volatilization from pig slurries in a semiarid agricultural rainfed area
    (MDPI, 2023) Jiménez de Santiago, Diana Elisa; Ovejero, Jonatan; Antúnez Pujol, Montserrat; Bosch Serra, Àngela D.
    Slurries are one of the main NH3 emission sources. Nitrogen losses impact air quality, and they constrain the sustainability of farming activities. In a rainfed Mediterranean agricultural system, the aim was to quantify NH3 emissions at a time when plants do not yet cover the soil surface and according to fertilization practices. One treatment was slurry from fattening pigs (PSF) applied before cereal sowing and incorporated into the soil; two treatments were PSF or from sows (PSS) applied at the cereal tillering stage (topdressing); and two more treatments received slurries twice, before sowing and as topdressing. Ammonia emissions were quantified with semi-static chambers during 145 h (before sowing) and 576 h (at cereal tillering) after slurry application. Before sowing, tillage after slurry application controlled NH3-N emissions, but they accounted for 14% of the total NH4-N applied. At tillering, average NH3-N emissions also accounted for ca. 14% of total NH4-N applied as PSF or PSS, respectively. Slurry dry matter from 84 kg m-3 (PSS) up to 127 kg m-3 (PSF), combined with low soil moisture content (below 30% of water holding capacity) at application time, helped in NH3 emission control. Slurry applications before sowing did not enhance later NH3-N emissions at topdressing.
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    Open Access
    Proton binding characteristics of dissolved organic matter extracted from the north atlantic
    (American Chemical Society, 2024) Lodeiro, Pablo; Rey Castro, Carlos; David, Calin; Humphreys, Matthew P.; Gledhill, Martha
    Marine dissolved organic matter (DOM) presents key thermodynamic properties that are not yet fully constrained. Here, we report the distribution of binding sites occupied by protons (i.e., proton affinity spectra) and parametrize the median intrinsic proton binding affinities (log K-H) and heterogeneities (m), for DOM samples extracted from the North Atlantic. We estimate that 11.4 +/- 0.6% of C atoms in the extracted marine DOM have a functional group with a binding site for ionic species. The log K-H of the most acidic groups was larger (4.01-4.02 +/- 0.02) than that observed in DOM from coastal waters (3.82 +/- 0.02), while the chemical binding heterogeneity parameter increased with depth to values (m(1)= 0.666 +/- 0.009) ca. 10% higher than those observed in surface open ocean or coastal samples. On the contrary, the log K-H for the less acidic groups shows a difference between the surface (10.01 +/- 0.08) and deep (9.22 +/- 0.35) samples. The latter chemical groups were more heterogeneous for marine than for terrestrial DOM, and m(2) decreased with depth to values of 0.28 +/- 0.03. Binding heterogeneity reflects aromatic carbon compounds' persistence and accumulation in diverse, low-abundance chemical forms, while easily degradable low-affinity groups accumulate more uniformly in the deep ocean.
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    Open Access
    Photovoltaics for buildings and greenhouses: Organic solar cells and other technologies
    (Elsevier, 2023) Lamnatou, Chrysovalantou; Chemisana Villegas, Daniel
    In light of the increasing environmental awareness, the present study is about life-cycle assessment of the Balance of System (BOS) of Photovoltaics (PVs), underlining the advantages of Organic Photovoltaics (OPVs). A closer look at the literature on PV shows that there is a dearth of studies which place emphasis on PVs with lightweight BOS systems, highlighting the importance of flexible/lightweight PV modules for buildings and greenhouses. To fill this literature gap, the present article sets out to: i) offer an overview of BOS, ii) analyse the environmental profile of the BOS of a grid-connected PV rooftop system, iii) estimate the avoided impacts of PV systems which need small amounts of BOS materials and iv) present critical factors for OPV greenhouses and PV challenges. Considering the results of the present study as well as results of other studies, BOS impacts range from: i) 6 to 181 kg CO2.eq/m2 of PV module, ii) 55 to 1900 MJprim/m2 of PV module. On the other hand, taking into account that the avoided impacts of a PV system are inextricably linked to the electricity mix of a certain country, a case study based on different electricity mixes (OPV system: Spain; Italy; Portugal) is presented.
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    Open Access
    Evaluación de la gestión del nitrógeno mediante monitorización del agua de drenaje de una zona regable
    (Interempresas Media, 2022) Villar Mir, Josep Ma.; Altés, Víctor; Pascual Roca, Miquel
    En el escenario actual de incertidumbre y alza de precios de los productos agrícolas es necesario realizar un manejo adecuado de la maquinaria, el agua o los fertilizantes. A lo largo de este artículo se presenta una metodología para la evaluación de la gestión del nitrógeno en una zona regable, con una combinación del conocimiento de los agricultores y técnicos de la zona a estudiar con el uso de Sistemas de Información Geográfica (SIG) y los datos abiertos de mapas de cultivos. De este modo es posible conocer cómo se está realizando la fertilización y si ésta tiene margen de mejora. Se presenta un ejemplo práctico, así como referencias a estudios realizados de este tipo.
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    Open Access
    Difusión de los aportes de la ciencia paleontológica peruana en las estampillas y marcas postales del correo del Perú (1999-2022)
    (Universidad Nacional de Trujillo, 2023-06-01) Astudillo, Heracli; Villaseca-Robertson, Andrea
    En este trabajo se presentan todas las estampillas postales, relacionadas con el registro fósil peruano, emitidas por el servicio de correos del Perú, entre 1999 y 2022.