92516 research outputs found
Sort by
Recycling end-of-life solar panels: A comparative study of thermal and solvent delamination techniques
No full textThe rapid expansion of photovoltaic (PV) energy has led to a growing concern regarding the management of endof-life solar panels. Projections indicate a substantial growth of PV panel waste in the coming years, highlighting
the urgent need for effective disposal solutions. In this study, the most critical phase in the recycling of Si-based
PV panels, i.e., module delamination, was investigated under two scenarios: solvent- and thermal-based methods.
The study encompasses the complete recycling chain, from initial module disassembly to its delamination and the
comprehensive characterization of the resulting material fractions. Neuro-fuzzy models were developed to
maximize the efficiency of the delamination process. An innovative simulated distillation with an equivalence to
a 100 theoretical-plate physical distillation procedure was also designed to identify potential valorizable hydrocarbons. The most effective solvent-based delamination process was achieved with toluene for 180 min
assisted by ultrasounds, reaching a separation degree of 0.75 (complete glass and backsheet detachment, but
with polymer residues on the Si cell surface). Thermal delamination proved significantly more effective,
achieving complete separation (degree = 1) with full encapsulant removal, recovery of silicon cells without
microcracks, and isolation of high-purity metallic filaments, under a range of conditions (350–550 ◦C, 30–50
min, 21 % O2). Finally, simulated distillation confirmed the presence of valorizable hydrocarbons with the
following product distribution: 65 % light naphtha, 17 % heavy naphtha, 16 % kerosene, and 2 % gas oil (dieselrange).Greening Global, the CDTI (Centro para el Desarrollo Tecnológico e Innovación) - CTA (Corporación Tecnológica de Andalucía)
Advancing ex-vivo meniscus tissue characterization: sensitivity and accuracy of shear modulus measurements via supersonic shear imaging vs. biomechanical testing
No full textNon-invasive measurement of meniscal mechanical properties is critical for advancing both meniscal pathophysiology research and represents a critical advancement in musculoskeletal diagnostics. This study aimed to
evaluate the accuracy and sensitivity of ultrasound-based stiffness measurements using Supersonic Shear Imaging (SSI) compared to low-strain and high-strain tensile testing and to assess the ability of SSI to detect
meniscal degeneration. Sixty bovine menisci were analyzed across seven regions, covering including the tibial
and femoral layers, as well as the circumferential region, using shear wave elastography (SWE) and tensile
testing. To evaluate tissue degeneration, samples underwent mechanical testing both before and after being
subjected to five freeze–thaw cycles. Shear stiffness values obtained from SSI were compared against tensilederived parameters, including shear modulus at low strain, linear stiffness, and Young’s modulus measured
from stress–strain curves up to failure, assuming small-amplitude shear wave propagation. Depth-dependent
effects in Region of Interest (ROI) selection were evaluated, and Different SSI transducers were assessed using
various receiver tests. Our results demonstrate significant agreement between SSI measurements and mechanical
properties: 88 % sensitivity for stiffness and Young’s modulus in circumferential samples, and 91 % for shear
modulus at 3 % strain in femoral and tibial regions. While intact samples showed strong positive correlations
between stiffness measures, degenerated tissue exhibited inverse relationships. Our comprehensive transducer
comparison and receiver tests yielded optimized protocols for ROI selection. Crucially, we identify for depthdependent measurement artifacts, proposing the ROI selection guidelines specific to meniscal elastography.
This depth-aware acquisition strategy, together with the observed sensitivity of SSI to degeneration (p < 0.001),
supports its clinical utility in contexts where conventional ultrasound elastography is limited. Overall, these
findings validate SSI as a sensitive technique for biomechanical assessment of the meniscus, with direct translational potential for diagnosing degeneration and monitoring post/pre surgical tissue remodeling.Ministerio de Ciencia, Innovación y Universidades (MICIU/AEI/10.13039/501100011033) y Fondo Europeo de Desarrollo Regional (ERDF/EU) - (Grant PID2023-147901OB-I00; Grant PCI2022-135048-2)European Union – Listen2Future Project (Grant 101096884)Junta de Andalucía – Consejería de Universidad, Investigación e Innovación (Grant P21.00182)Universidad de Granada / CBUA (Open access
Invariant constant mean curvature tubes in homogeneous spaces
No full textWe study the global geometry of families of tubes of constant mean curvature
invariant under screw-motions in homogeneous E(κ, τ)-spaces. In particular, we
study embeddedness and prove a foliation result. Moreover, we numerically analyze
the isoperimetric profile in the compact case.MCIN/AEI/10.13039/501100011033 – (PID2022-142559NB-I00, CEX2020-001105-M, IMAG–María de Maeztu grant
High dose-rate gamma radiation response of commercial off-the-shelf diodes
No full textIonizing radiation plays a vital role in numerous applications, such as radiation safety, industrial monitoring, and
medical dosimetry. This study evaluates the performance of four commercially available off-the-shelf (COTS)
rectifier diodes—1N4007, UF4007, BY203–20S, and GP02-40—as detectors for high dose-rate gamma radiation,
using a Cobalt-60 source. Their sensitivity, its variation with accumulated dose (SVWD), and with temperature
(SVWT) were assessed using an ionization chamber as a reference dosimeter. The results indicate that two diode
models exhibit promising performance for dosimetric applications. In fact, the BY203–20S and UF4007 showed a
sensitivity ~7.5 times higher than the ionization chamber, and minimal sensitivity variation with accumulated
doses (~5 % and ~2 %) up to 23 and 33 kGy, respectively. The 1N4007 demonstrated the highest sensitivity (~9
times higher), but also the most significant sensitivity decay, ~-13 % at 22 kGy. In contrast, GP02-40 diode
exhibited the lowest sensitivity, the greatest sensitivity decay, and the lowest reproducibility among the tested
samples. Thermal compensation procedures have been applied to the diode dark current and SVWT, monitoring
in real time the device temperature with the UF4007 as sensor. Around +0.4 %/◦C of increase in relative sensitivities were measured for BY203–20S and UF4007 diodes, highlighting the relevance of compensation the
temperature effects for accurate measurements. These findings suggest that low-cost rectifier COTS diodes may
serve as viable candidates for high dose-rate radiation detection as compact and affordable devices.MCIN/AEI/10.13039/501100011033 (PID2022-137543NB-I00; t IJC2020-
043307-I)European Union NextGeneration EU/PRTR (IJC2020-
043307-I
Impact of finite-range spin-orbit and tensor terms in Gogny EDF on structure and fission properties
No full textEnergy Density Functionals are of major interest for the study of the atomic nucleus as, coupled with mean-field and beyond N-body approaches, they are applicable to the whole nuclear chart, including superheavy elements. On the one hand, the growing need for nuclear data and, on the other hand, the large amount of experimental data on exotic nuclei explain the work carried out on these phenomenological forms of the nucleon-nucleon interaction to analyze the richness of the nuclear phenomena. In this paper, we propose a fully finite-range extension of the Gogny EDF, including a short-range spin-orbit term and a long-range tensor term. The original fitting protocol of the Gogny interaction has been adapted to include both finite range spin-orbit and tensor terms, adding new constraints and filters linked to relevant data. Nuclear matter, spectroscopic and fission properties are discussed, highlighting ways of improving EDFs when all spin and isospin exchanges are introduced with finite-range terms
Adaptive algorithm for pigment identification from unmixing spectral data: Case study with two versions of a XVI century painting
No full textOur thanks to Laura Figueroa for her contribution to the implementation of the superpixel segmentation and the analysis of preliminary trials data. This work was supported by Grant PID2021-124446NB-100 funded by MICIU/AEI /10.13039/501100011033 and by ERDF, EU and by the Ministry of Universities, Spain [grant number FPU2020-05532].Artists commonly use a relatively reduced palette of pigments and mix them in different proportions to increase the gamut of colors present on artworks. In this study, a complete workflow for pigment identification using spectral unmixing of reflectance spectra in the visible and near infrared is presented. The algorithm includes superpixel segmentation as pre-processing to reduce the number of spectra that are unmixed. Then, a pre-extracted set of relevant color instances from the painting is used to build an adaptive subset of candidate pigments from a reference palette, and pigment identification is achieved by superpixel voting within the reduced subsets corresponding to the automatically extracted endmembers presence maps. Two different moments in time of a Maternity of the 16th century (original and restored) and a modern replica of the same painting are used to showcase the performance of the algorithm, which is able to correctly identify 80 % of the pigments present from a reference library of 23 pigments, taking less than three minutes for processing around 7000 spectra.MICIU/AEI /10.13039/501100011033, PID2021-124446NB-100ERDF, EU and by the Ministry of Universities, Spain, FPU2020-0553
Well-posedness and numerical analysis of an elapsed time model with strongly coupled neural networks
No full textThe elapsed time equation is an age-structured model that describes the dynamics of interconnected spiking neurons through the elapsed time since the last discharge, leading to many
interesting questions on the evolution of the system from a mathematical and biological point
of view. In this work, we deal with the case when the transmission after a spike is instantaneous
and the case with a distributed delay that depends on the previous history of the system, which
is a more realistic assumption. Since the instantaneous transmission case is known to be ill-posed
due to non-uniqueness or jump discontinuities, we establish a criterion for well-posedness to
determine when the solution remains continuous in time, through an invertibility condition that
improves the existence theory under more relaxed hypothesis on the nonlinearity, including the
strongly excitatory case. Inspired in the existence theory, we adapt the classical explicit upwind
scheme through a robust fixed-point approach and we prove that the approximation given by
this scheme converges to the solution of the nonlinear problem through BV-estimates and we
extend the idea to the case with distributed delay. We also show some numerical simulations
to compare the behavior of the system in the case of instantaneous transmission with the case
of distributed delay under different parameters, leading to solutions with different asymptotic
profiles.ANID, Chile - (ECOS200018, general project funding; FB210005; Fondecyt-1220869)MCIN/AEI/10.13039/501100011033, European Union NextGenerationEU/PRTR - (Juan de la Cierva FJC2021-046894-I
Addressing data quality decompensation in federated learning via dynamic client selection
No full textIn cross-silo Federated Learning (FL), client selection is critical to ensure high model performance, yet it remains challenging due to data quality decompensation, budget constraints, and incentive compatibility. As training progresses, these factors exacerbate client heterogeneity and degrade global performance. Most existing approaches treat these challenges in isolation, making it difficult to optimize multiple factors in conjunction. To address this, we propose Shapley-Bid Reputation Optimized Federated Learning (SBRO-FL), a unified framework integrating dynamic bidding, reputation modeling, and cost-aware selection. Clients submit bids based on their perceived data quality, and their contributions are evaluated using Shapley values to quantify their marginal impact on the global model. A reputation system, inspired by prospect theory, captures historical performance while penalizing inconsistency. The client selection problem is formulated as a 0–1 integer program that maximizes reputation-weighted utility under budget constraints. Experiments on four benchmark datasets demonstrate the framework’s effectiveness, improving final model accuracy by an average of 10.3 % over random selection, with gains exceeding 19 % on more complex datasets like CIFAR-10 and SVHN. Our results highlight the importance of balancing data reliability, incentive compatibility, and cost efficiency to enable scalable and trustworthy FL deployments.National Natural Science Foundation of China (Grant 72171065)Shaanxi Key Laboratory of Information Communication Network and Security (Open Fund Grant ICNS201807)Instituto Nacional de Ciberseguridad (INCIBE) – Universidad de Granada - Next Generation EU (Strategic Project IAFER-Cib C074/23)China Scholarship Council (Project ID: 202308330099)Universidad de Granada / CBUA (Open access
Extracellular matrix properties of porcine reproductive scaffolds depend on storage temperature
No full textDecellularized extracellular matrix (dECM) scaffolds show great promise in the field of reproductive medicine for the treatment of reproductive tract pathologies, the engineering of artificial organs to restore fertility, or the improvement of assisted reproduction techniques. Although protocols for decellularizing oviducts and uteri to obtain dECM scaffolds are well established, the optimal storage conditions required to maintain the structural and biochemical integrity of these scaffolds remain poorly defined. In this study, we evaluated the effects of one-month storage at three different temperatures (4 °C, −20 °C, and −80 °C) on the stability of dECM scaffolds from porcine oviducts and uteri. Although storage did not alter the macroscopic structure, microscopic analyses showed that storage at −80 °C resulted in a reduction in glycosaminoglycans in the oviduct, while storage at 4 °C altered the histological pattern of uterine scaffolds. Proteomic analysis revealed that freezing conditions (−20 °C and −80 °C) better preserved matrix proteins associated with key functions, such as regeneration and cell adhesion. Frozen storage was also associated with greater biomechanical strength, reduced bacterial growth, and improved biocompatibility of the scaffolds. Together, these results demonstrate that storage conditions directly influence the quality of dECM scaffolds, highlighting that freezing temperatures are more suitable for short-term storage.Fundación Seneca-Agencia de Ciencia y Tecnología de la Región de Murcia - (22001/PI/22)University of Murcia - (R-496/2022)
Enhancing biomass properties for biofuels: A comparative analysis of pyrolysis and hydrothermal carbonization technologies
No full textThis study analyzes and compares the effects of pyrolysis and hydrothermal carbonization (HTC) on biomass
sourced from southern Spain, focusing on their potential for biofuel production. Five biomass types including
orange, olive and pine-tree prunings, and almond and pistachio shells were selected due to their widespread
availability and renewable energy potential. Pyrolysis experiments were conducted in a fixed-bed reactor at 450,
500, and 550 ºC for 30 and 60 min, while HTC was performed in an autoclave reactor at 180, 220, and 260 ºC for
60, 120 and 240 min. The resulting biochar and hydrochar were characterized through elemental analysis, ash
content, higher heating value (HHV), energy yield (EY), and global energy efficiency (GEE). The results indicate
that, when temperature increases, both processes reduce solid yield while promoting gas formation and pyrolysis
generally enhances the carbon content and HHV of the biomass, particularly in pine and pistachio, which
reached maximum HHV values of 27.32 MJ/kg and 25.39 MJ/kg, respectively. However, pyrolysis also leads to
increased ash content. Conversely, HTC significantly reduces ash content offering a cleaner solid product and
retains a higher EY, with pine hydrochar achieving an EY of 89.26 % at 180◦C for 240 min. The global energy
efficiency (GEE) analysis further supports HTC as a more energy-efficient process, with values reaching 91.80 %
for pine hydrochar. Additionally, structural and combustion analyses of the best samples (obtained from pine
biomass) revealed that while pyrolysis produces a more thermally stable and porous carbon matrix, HTC-treated
samples retain more functional groups, exhibit a two-stage combustion profile, and display significantly higher
initial combustion rates, underscoring their potential for rapid energy release in biofuel applications. These
findings highlight the trade-offs between both methods