•We propose a model to simulate infiltration into heterogeneous soils.•The model was validated by studying the water flow in a homogeneous soil.•The model predicts the surface runoff for both ...homogeneous and stratified soils.
We propose a model to simulate infiltration into heterogeneous soils, with arbitrary initial water content distributions, subject to unsteady rainfall, and under the free draining condition. It is a mass conservative theoretical approach based on the numerical resolution of the one-dimensional Richards equation. The model tracks the movement of the wetting front along the soil profile, checks the ponding status, and handles the shift between ponding and non-ponding conditions in the course of the simulation. It partitions the rainfall input into infiltration and surface runoff whenever the upper soil layer is saturated. We validate our theoretical approach by comparing the results for a homogeneous soil under steady rainfall with those calculated with Chemflo-2000. The differences between our approach and the modified Green-Ampt model are showed by considering the infiltration under unsteady rainfall conditions. Finally, we illustrate the model capabilities by examining the water flow and surface runoff for both homogeneous and stratified soils under intense rainfall events.
Two processes (with cooled and adiabatic fixed bed reactors) for direct biogas methanation were assessed using detailed balances and rate-based models. The simulations show that they are capable to ...produce synthetic natural gas (SNG) in one or two steps without further upgrading after the reactors. The sizes for cooled beds are smaller than for adiabatic reactors due to heat transfer that reduces the needs for recirculation and allows for more favorable temperature profiles; although a more complex heat exchanger systems is then required for cooling.
Thus, the processes are compared to identify the most cost-effective operating conditions for each system, since all considered optimized systems can meet product specifications and technical aspects alone are not enough to decide which the most beneficial approach is. The economic analysis shows that the costs dominant come from biogas and hydrogen and total costs production of SNG (0.54–0.58 €/Nm3SNG) is still high compared to natural gas. Cheap biogas and electricity may lead to more competitive SNG costs, while the methanation step can effectively remove the problems related to biogas or hydrogen uses at the same time that is a minor part of final costs.
•Direct biogas methanation with adiabatic & cooled reactors is capable to produce SNG.•Reactors show the potential of thermal optimization to simplify & intensify processes.•Cooled systems are more flexible to operate, but more complex for thermal control.•Methanation is a minor part of costs, but technical design & uses are very relevant.•The total cost of SNG is still high but it is very sensitive to biogas & power prices.
Abstract
When electric conductors differ from their mirror image, unusual chiral transport coefficients appear that are forbidden in achiral metals, such as a non-linear electric response known as ...electronic magnetochiral anisotropy (eMChA)
1–6
. Although chiral transport signatures are allowed by symmetry in many conductors without a centre of inversion, they reach appreciable levels only in rare cases in which an exceptionally strong chiral coupling to the itinerant electrons is present. So far, observations of chiral transport have been limited to materials in which the atomic positions strongly break mirror symmetries. Here, we report chiral transport in the centrosymmetric layered kagome metal CsV
3
Sb
5
observed via second-harmonic generation under an in-plane magnetic field. The eMChA signal becomes significant only at temperatures below
$${T}^{{\prime} }\approx $$
T
′
≈
35 K, deep within the charge-ordered state of CsV
3
Sb
5
(
T
CDW
≈ 94 K). This temperature dependence reveals a direct correspondence between electronic chirality, unidirectional charge order
7
and spontaneous time-reversal symmetry breaking due to putative orbital loop currents
8–10
. We show that the chirality is set by the out-of-plane field component and that a transition from left- to right-handed transport can be induced by changing the field sign. CsV
3
Sb
5
is the first material in which strong chiral transport can be controlled and switched by small magnetic field changes, in stark contrast to structurally chiral materials, which is a prerequisite for applications in chiral electronics.
This paper describes teachers' perceptions of their ICT and media competencies, and the importance they assign to these competencies in teacher training. A questionnaire was used as a data collection ...instrument based on UNESCO's proposals on iCt (Information and Communication Technologies) and MIL (Media and Information Literacy). A total of 402 teachers and pre-service teachers took part in the questionnaire. This is an exploratory cross-sectional study where quantitative descriptive and correlational methodology is used. Findings reveal that the self-perceived competence of teachers is low and that the self-perceived level is always lower than the importance given to the corresponding competence. Greater importance is assigned to MIL competencies than to ICT competencies of teachers; this questions the tendency to prioritize technological and didactic training over media education training. It concludes with the need for a paradigm shift towards convergence in teacher training policies for the digital age, and a global model of teacher competencies in media and ICT (COMPROMETIC) is proposed that integrates MIL competencies with those of ICT teachers. The model is based on a double convergence: that of different literacies, and that of the resulting multi-literacy with the specific training of education professionals in ICT and media.
Nowadays, virtual reality technologies and immersive virtual reality (VR) apps allow people to view, explore, engage with and learn about historic monuments and buildings, historic sites, and even ...historic scenes. To preserve our cultural heritage for future generations. it is essential that damaged and dilapidated historic artefacts are accurately documented, and that steps are taken to improve user experiences in the areas of virtual visits, science and education. This paper describes an approach to reconstruct and restore historic buildings and mural paintings. The work process uses digital models that are then inserted into an interactive and immersive VR environment. Windows-Mixed Reality is used to visualize the said VR environment. The work method was applied at a United Nations Educational, Scientific and Cultural Organisation (UNESCO) World Heritage Site in Tenerife (Canary Islands, Spain), thereby creating a virtual three dimensional (3D) rendering of the architectural structures of the St Augustine Church in La Laguna and its murals. A combination of topography and terrestrial photogrammetry was used to reconstruct its architectural features, and the digital imaging tool DStretch® to recover its murals. The resulting 3D model was then inserted into an immersive and interactive VR environment created using the cross-platform game engine Unity. One of the greatest challenges of this project revolved around recovering the dilapidated and virtually nonexistent mural paintings using DStretch®. However, the final result is an immersive and interactive VR environment containing architectural and artistic information created within the video game engine Unity, which thereby allows the user to explore, observe and interact with a cultural heritage site in real time.
The European energy transition implies a relevant increase of renewable energies in the electric power generation mix. Integrating additional renewables is becoming more challenging due to their ...variability. Spain's peninsular situation aggravates this problem because it is an electric island. Within this framework, Liquid Air Energy Storage (LAES) is a promising technology for balancing the power grid. This work proposes a transient thermodynamic modelling of a 100 MW LAES plant. The cycle incorporates a packed-bed cold-storage system to enhance the charge/discharge efficiency. The appearance of a thermocline in the cold-storage unit is relevant regarding the round-trip efficiency. An economic study based on the simulation results is performed considering different scenarios of renewables grid penetration (photovoltaic and wind power). Depending on the installed LAES capacity, the levelized cost of delivered energy is evaluated. The results suggest that it is more interesting to store photovoltaic energy in the daytime peak hours and release energy during the night-time valleys to maximize the use of storage plants. This allows the levelized cost of energy and storage to be reduced to values as low as 150 and 50 €/MWh respectively. These prices are competitive with compressed air energy storage and even with pumped-hydro storage.
Display omitted
•Transient LAES simulation including packed-bed cold storage unit.•Techno-economical study of LAES integration into the Spanish electric power grid.•LCOE ∼ 250 €/MWh in valley charge/peak discharge configuration.•LCOE ∼ 150€/MWh with the opposite concept considering important PV power increase.•Competitive with pumped-hydro storage or Compressed Aire Energy Storage (CAES).
We conducted the first phase 0 clinical trial in oncology of a therapeutic agent under the Exploratory Investigational New Drug Guidance of the US Food and Drug Administration. It was a ...first-in-human study of the poly (ADP-ribose) polymerase (PARP) inhibitor ABT-888 in patients with advanced malignancies.
ABT-888 was administered as a single oral dose of 10, 25, or 50 mg to determine the dose range and time course over which ABT-888 inhibits PARP activity in tumor samples and peripheral blood mononuclear cells, and to evaluate ABT-888 pharmacokinetics. Blood samples and tumor biopsies were obtained pre- and postdrug administration for evaluation of PARP activity and pharmacokinetics. A novel statistical approach was developed and utilized to study pharmacodynamic modulation as the primary end point for trials of limited sample size.
Thirteen patients with advanced malignancies received the study drug; nine patients underwent paired tumor biopsies. ABT-888 demonstrated good oral bioavailability and was well tolerated. Statistically significant inhibition of poly (ADP-ribose) levels was observed in tumor biopsies and peripheral blood mononuclear cells at the 25-mg and 50-mg dose levels.
Within 5 months of study activation, we obtained pivotal biochemical and pharmacokinetic data that have guided the design of subsequent phase I trials of ABT-888 in combination with DNA-damaging agents. In addition to accelerating the development of ABT-888, the rapid conclusion of this trial demonstrates the feasibility of conducting proof-of-principle phase 0 trials as part of an alternative paradigm for early drug development in oncology.
This work is devoted to evaluating the relationship between the oxygen content and catalytic activity in the CO oxidation process of the 6H-type BaFeO3−δ system. Strong evidence is provided about the ...improvement of catalytic performance with increasing Fe average oxidation state, thus suggesting the involvement of lattice oxygen in the catalytic process. The compositional and structural changes taking place in both the anionic and cationic sublattices of the catalysts during redox cycles have been determined by temperature-resolved neutron diffraction. The obtained results evidence a structural transition from hexagonal (P63/mmc) to orthorhombic (Cmcm) symmetry. This transition is linked to octahedra distortion when the Fe3+ concentration exceeds 40% (δ values higher than 0.2). The topotactical character of the redox process is maintained in the δ range 0 < δ < 0.4. This suggests that the cationic framework is only subjected to slight structural modifications during the oxygen exchange process occurring during the catalytic cycle.
Abstract In this article, we present the findings of a comprehensive longitudinal social network analysis conducted on Twitter across four consecutive election campaigns in Spain, spanning from 2015 ...to 2019. Our focus is on the discernible trend of increasing partisan and ideological homogeneity within interpersonal exchanges on this social media platform, alongside high levels of networking efficiency measured through average retweeting. This diachronic study allows us to observe how dynamics of party competition might contribute to perpetuating and strengthening network ideological and partisan homophily, creating ‘epistemic bubbles’ in Twitter, yet showing a greater resistance to transforming them into ‘partisan echo-chambers.’ Specifically, our analysis reveals that the rise of a new radical right-wing party (RRP), Vox, has heightened ideological homogeneity among users across the entire ideological spectrum. However, this process has not been uniform. While users aligned with mainstream political parties consistently share content that reinforces in-party affinity, resulting in highly efficient ‘epistemic bubbles,’ the emergence of the RRP has given rise to a distinct group of users associated with the most extreme partisan positions, characterized by a notable proportion of out-partisan hostility content, which has fostered the creation of low-efficient 'partisan echo-chambers.'
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