Search Results (15,178)

The use of smartphones as analytical instruments is becoming increasingly widespread due to their ease of use and low cost. However, it has limitations, such as dependence on the smartphone’s sensor, the light source and the environment, which hinders the reproducibility and comparability of results. This paper presents the development of a portable device, called DUNI, which can be attached to any smartphone and is designed to overcome these limitations. The device, manufactured using 3D printing and with an average cost of €35, consists of an integrating sphere, which incorporates a lighting-electronic system, as well as accessories for measuring on different surfaces. It has been optimised by evaluating the influence of the optical geometry, the size and reflective coating of the sphere, the lighting conditions, and the electronic stability on measurement performance. It has been applied to the determination of hydrogen peroxide and biogenic amines in synthetic samples, achieving relative errors of less than 5% and detection limits between 3 and 6 µM. Overall, the device we have developed constitutes a portable, versatile and low-cost platform that enables quantitative colorimetric measurements using smartphones under controlled lighting conditions, with potential applications in on-site analysis and resource-limited settings. Full article

This study explores the possibility of making cardboard and molded egg carton packaging from corn residues and common reed as alternatives to wood-based pulp. Six formulations were made: corn husks (CHs), corn leaves (CLs), corn leaves (35%) plus corn husks (30%) and a corn blend (15%) of wollastonite (CaSiO₃) (CH + CL + W), a corn blend (CH + CL: husks 60%, leaves 40%), mixed corn waste (MCW) and shredded common reed (SR). Optical microscopy was used to evaluate the fiber morphology, including the calculation of the flexibility coefficient, the cell wall rigidity and the Runkel ratio, for raw materials and fiber after alkaline hydrolysis and casting of egg cartons in silicone molds. The grammage, burst strength and index, folding endurance, thickness and moisture content were measured in the cardboard samples, while warping, compressive deformation, moisture and ink absorption were measured in the egg cartons. The flexibility coefficient of the common reed fibers (64.5%) was better than that of the corn fibers (23.6%), and so was the Runkel ratio (0.86 vs. 1.2). In the case of cardboard formulations, the maximum burst strength (462.4 kPa) and the maximum burst index (3.0 kPa·g/m²) values were obtained with the MCW formulation, and the highest folding endurance (42 and 38 double folds) was obtained with the CH and SR formulations, respectively. The addition of wollastonite improved folding endurance to 28 double folds and reduced moisture content to 4.1%, whereas the moisture content was reduced but burst strength decreased to 250.5 kPa. Egg cartons made from corn were found to satisfy all the requirements tested for good packaging, while the reed-based cartons were found to have inadequate ink absorbency time (20 min), making them less printable. Overall, mixed corn residues seem to be the most promising raw materials for sustainable packaging, and wollastonite can be used to adjust the flexibility–strength balance. Full article

Flexible transparent conductive films (TCFs) and their applications have attracted extensive interest. Silver nanowires (AgNWs) have been explored to replace conventional indium tin oxide (ITO) due to their high optical transmittance and superior electrical conductivity. Nevertheless, AgNWs tend to oxidize under ambient conditions, which weakens the conductive network and limits long-term performance. Spraying reduced graphene oxide (rGO) can stabilize the conductive network and inhibit oxidation, thereby enhancing the overall properties of the films. In this work, rGO/AgNW/PET TCFs were prepared using a spray-coating approach. The transmittance of the rGO/AgNW/PET TCFs was measured at 77% at 550 nm, accompanied by a sheet resistance of 6.8 Ω/sq. The films achieved the surface temperature of 95 °C at 6 V with stable operation while also achieving an electromagnetic interference shielding effectiveness of 27 dB. This structural design improves both performance and stability, offering great potential for flexible TCFs in advanced optoelectronic applications. Full article

Soil salinization threatens agricultural sustainability in arid zones, yet quantitative attribution of its spatiotemporal dynamics to multi-source drivers remains scarce at regional scales. To address this, we developed an explainable framework merging Sentinel-1/2, ERA5-Land, and topographic-hydrological indices with XGBoost, trained under weak supervision with proxy labels and independently validated using field-measured ECe. A 7-group, 44-feature ensemble with spatial block 5-fold cross-validation ensured robust assessment. SHapley Additive exPlanations (SHAP) quantified driver contributions and enabled a novel dominant driver zoning (DDZ) framework. Monitoring the Hexi Corridor and Tarim Basin (2017–2024) revealed contrasting trajectories: Hexi’s dynamics were primarily climate-driven (Aridity Index), whereas 19.2% of Tarim showed significant salinization along oasis–desert margins co-dominated by elevation, soil indices, and temperature. The model achieved spatial cross-validation R² values around 0.65. DDZ mapping showed climate dominance in 98.2% of Hexi compared to 76.5% in Tarim, where terrain and optical factors were more influential. The weak supervision strategy overcomes scarce in-situ measurements, while the DDZ maps identified that Land-use-dominated zones recorded the highest salinity, offering clear directives for targeted salinity control in arid basins. Full article

Distributed vibration sensing based on optical vector network analysis (OVNA) is a promising technique for measuring dynamic perturbations in optical fibers, but its practical use is limited by the high computational cost of short-time Fourier transform (STFT) and cross-correlation stages. In this work, we present a GPU-accelerated signal processing pipeline, together with an optimization strategy based on dataflow reduction, mixed-precision arithmetic, and hardware-aware tuning. The proposed implementation reduces the processing time for 200 sweeps from 64.7 s on a single-core CPU to 0.199 s on a modern GPU, while preserving the final shift results, with zero mismatches over 199,199 measurement points. Benchmarking across three GPU generations further shows that STFT benefits more from large on-chip cache resources, whereas cross-correlation scales more closely with memory bandwidth. These results suggest that modern GPUs can significantly reduce the computational burden of OVNA, as well as other distributed sensing methods with a similar processing flow, enabling kHz-rate aggregate throughput from batched processing, supporting real-time-oriented operation on modern GPUs. Full article

Molybdenum blue dispersions were synthesized via an ion-exchange approach using hydroquinone and glucose as reducing agents to clarify the influence of reductant chemistry on redox evolution and colloidal stability. Electrolyte-free conditions enabled controlled self-assembly of reduced polyoxomolybdate clusters. UV–Vis spectroscopy revealed characteristic absorption bands at ~750 and ~1100 nm associated with intervalence charge transfer in mixed-valence Mo⁵⁺/Mo⁶⁺ clusters, with hydroquinone stabilizing more deeply reduced clusters, while glucose-derived systems demonstrated a higher degree of reduction with a higher ratio of reducing agent to metal. Time dependence of oxidation–reduction potential and optical density measurements demonstrated prolonged redox equilibration and gradual self-organization over several weeks. Dynamic light scattering confirmed the formation of nanoclusters with comparable hydrodynamic diameters of approximately 3.5 nm for both reducing agents. Raman and FT-IR spectroscopy indicated structurally similar polyoxomolybdate frameworks. In contrast, electrokinetic measurements revealed pronounced differences in surface chemistry and stability: hydroquinone-derived dispersions exhibited robust, pH-independent electrostatic stabilization, whereas glucose-derived systems showed weaker, pH-dependent stabilization and rapid electrolyte-induced aggregation. These results demonstrate that the nature of the reducing agent has an impact on the synthesis and colloidal behavior of molybdenum blue dispersions synthesized by the ion-exchange route. Full article

Time-of-Flight (ToF) 3D imaging suffers from diverse systematic and non-systematic errors that limit its practical performance and reliability. Reliable simulation is critical for understanding these error mechanisms and guiding performance improvement. Therefore, this paper proposes a multi-error coupling simulation framework for ToF 3D imaging based on optical path unit decomposition. By decomposing the full light propagation chain and systematically integrating established typical error mechanisms into their corresponding physical stages, we produce simulation results that closely match real-world sensor measurements. Validated through laboratory and real-scene experiments, the proposed method outperforms mainstream approaches in RMSE, PSNR, and relative error metrics, accurately reproducing the depth distortion and noise characteristics of real ToF sensors. This multi-error coupled modeling method effectively bridges the gap between simulation and actual measurement, offering a credible reference for ToF system error evaluation, parameter optimization, and performance enhancement. Full article

Capacitive sensing offers a low-power, non-optical route for automated insect monitoring, but architecture-level benchmarking under shared geometry remains limited. Rather than presenting a general framework, this study proposed a configuration-specific laboratory benchmark comparing four sigma-delta and charge-transfers in a 6 mm dual-arc conduit at 25 °C, targeting six adult terrestrial arthropod species spanning a 25-fold range of the body cross-sectional area. Static measurements showed a strong linear relationship between ΔC_static and body cross-sectional area (17.96 fF/mm², r = 0.995), supporting first-pass conduit sizing and detectability screening. In contrast, transit amplitudes were not monotonic with body size because posture, motion, and gap occupancy affected waveform shape. Under chamber conditions, static sensitivity degraded by less than 3.2% across all architectures from RH 40% to 80%. However, under the deployment-oriented noise model, SNR_FR degradation was substantially higher for charge-transfer devices (64.8–66.8%) than for Σ–Δ devices (≤35.5%), because the composite noise floor amplifies the effect of humidity-induced baseline drift. These results generated a conduit-specific reference dataset for preliminary capacitance-to-digital converter (CDC) selection within the tested 6 mm dual-arc geometry. In addition, the experimental validation focused on laboratory baseline noise characterization, long-term drift, and trap-integrated testing in temperature-controlled environments and natural-locomotion trials, providing critical information on configuration-specific architectures and body-size-scaling reference. This study serves as an initial step toward real-world capacitive insect sensing. Future studies will investigate additional conduit geometries and insect species to improve the robustness of the proposed framework. Full article

This study investigates lignin as a renewable functional dye capable of simultaneously imparting coloration and multifunctional performance to cotton textiles, with particular emphasis on how chitosan polymorphs influence lignin-mediated silver nanoparticle (AgNP) systems. Cotton fabrics were pretreated with α- or β-chitosan crosslinked with glyoxal and subsequently dyed with lignin in the presence of silver ions to generate lignin-mediated AgNPs. Inductively coupled plasma optical emission spectrometry (ICP–OES) analysis showed that α-chitosan retained a higher silver content (40.7 mg/kg) than β-chitosan (14.7 mg/kg). Transmission electron microscopy (TEM) revealed that α-chitosan produced larger AgNPs (≈13.6 nm), whereas β-chitosan was associated with smaller measurable nanoparticles (≈4.3 nm). Despite lower silver loading, β-chitosan–modified fabrics exhibited higher antibacterial activity against Staphylococcus aureus (82.6%) than α-chitosan-modified fabrics (68.7%). These results suggest that antibacterial performance in lignin–silver coating systems may depend not only on silver loading, but also on the distribution and accessibility of active components within the coating layer. In addition, the coatings improved UV protection, tensile properties, and color strength. Overall, the findings demonstrate that chitosan polymorphism plays an important role in controlling nanoparticle characteristics and multifunctional performance in lignin-based textile systems. Full article

A comprehensive first-principles investigation of bulk and surface Cu defects in Zn-based chalcogenides (ZnO, ZnS, and ZnSe) is presented, aimed at assessing the effect of Cu doping on the optoelectronic properties of these materials and at addressing the photocatalytic activity towards the hydrogen evolution reaction (HER). Defect formation energies, adiabatic and optical charge-transition levels of the bulk materials are determined, and their dependence on growth conditions and Fermi-level position is analysed. The results indicate that, whereas ZnO supports both donor- and acceptor-like Cu defects with pronounced Jahn-Teller distortions, ZnS and ZnSe predominantly stabilise substitutional Cu as a mid-gap acceptor with weaker electron-lattice coupling and similar absolute transition levels. Calculated vertical transition energies rationalise the characteristic emission of Cu-doped samples in terms of defect-mediated optical cycles. The focus is then placed on surface energetics, which differ markedly from bulk behaviour and critically influence photocatalytic performance. Explicit modelling of HER demonstrates that Cu substitution dramatically reduces the overpotential on ZnS and ZnSe by tuning hydrogen adsorption toward the Sabatier optimum, while in ZnO the beneficial effect of Cu doping is diminished by the excessive strengthening of the adsorbate-surface interactions. Finally, the measured HER activities are rationalised by proposing a defect-mediated mechanism involving electron trapping at the surface Cu site, cooperative proton adsorption, and hydride formation. These findings establish defect thermodynamics and surface charge localisation as key design parameters for optimising materials engineering strategies in photocatalytic applications. Full article

Background: Intracranial hypertension is a critical complication of acute intracerebral hemorrhage (ICH), contributing to high early mortality and poor functional outcomes. Invasive intracranial pressure (ICP) monitoring remains the gold standard but carries procedural risks and is resource-intensive. This study evaluated the diagnostic and prognostic utility of optic nerve sheath diameter (ONSD) ultrasonography and transcranial Doppler (TCD)-derived pulsatility index (PI) as non-invasive ICP surrogates in patients with severe ICH. Methods: A prospective observational study was conducted in 42 patients with acute ICH who underwent concurrent invasive ICP monitoring and serial ONSD/PI measurements at 10 time points (T0–T9) between October 2021 and August 2024. Diagnostic performance was assessed using measurement-level receiver operating characteristic (ROC) curve analysis. Exploratory early mortality prediction was evaluated using random forest machine learning models incorporating ONSD, PI, age, and sex. Results: A total of 274 paired ONSD–PI–ICP measurements were obtained. Both ONSD and PI showed moderate positive correlations with invasive ICP (rho = 0.49 and 0.43, respectively; p < 0.001). ONSD demonstrated superior diagnostic accuracy for detecting ICP ≥ 20 mmHg (AUC = 0.83; optimal threshold: 5.88 mm; sensitivity: 81%; specificity: 82%) compared to PI (AUC = 0.75). In exploratory random forest analyses, the combined ONSD–PI model showed high apparent discrimination for elevated ICP detection (AUC = 0.98), while the model incorporating ONSD, PI, age, and sex showed promising but potentially optimistic discrimination for early mortality prediction (AUC = 0.95). These machine learning results should be interpreted cautiously because of the small sample size, repeated-measurement structure, measurement-level data partitioning, and limited number of early deaths. Conclusions: ONSD ultrasonography and TCD-derived PI showed promising performance as non-invasive ICP markers in severe acute ICH. However, because of the small sample size, repeated-measurement design, measurement-level analyses, and exploratory nature of the machine learning models, these findings require validation in larger external cohorts before routine clinical implementation. Full article

This paper reports on the performance of an optical voltage transducer (MVT) module after undergoing lightning impulse withstand tests. The device was designed to monitor the output voltage of a dedicated capacitive voltage divider (CVD) to facilitate a voltage sensor dedicated for 132-kV high voltage (HV) networks. Hard piezoelectric transducer (PZT) and fiber Bragg grating (FBG) technologies were combined in the module to serve as a voltage-to-strain-to-wavelength converter. The FBG peak wavelength shifts were calibrated against the input voltage to provide precise measurements of the network voltage. The module was subjected to lightning impulse withstand tests as per the requirements of the IEC 60044-7 and IEC 60060-1 standards, and the impact of the lightning impulses on the performance of the MVT module was evaluated based on the accuracy tests performed before and after the lightning impulse tests. The experimental results demonstrated that the MVT module successfully withstood the lightning impulse tests without any disruptive discharges or voltage collapses. The performance of the module was not affected by the lightning impulse tests within the practical constraints of the reference measuring equipment: its amplitude and phase errors remained within the original limits of ±0.1% and ±0.1° at 80–120% of the rated voltage, and below ±4% and ±2° at 2% of the rated voltage, respectively. Full article

The Garisenda Tower, along with the neighboring Asinelli Tower, is arguably the symbol of the city of Bologna. They are the sole remnants of about one hundred towers that formed the city’s skyline in medieval times. As such, the monitoring of their state of health has been of great interest to the scientific community for more than a century—one example being the studies of Prof. Cavani in the early 1900s. The Garisenda Tower, famous for its impressive lean, is the object of Structural Health Monitoring (SHM) involving a multitude of devices. Some examples are a 30 m long pendulum installed on the inside of the tower to measure the planar displacement of the tower’s top; Fiber-Optical Strings (FOSs) installed in the walls of the basement to measure their vertical deformation; and piezoelectric acoustic emission (AE) sensors, also installed on the walls of the tower’s basement to detect elastic waves generated by micro-cracking. This rich experimental setup allows for the investigation of the tower’s stability and damage assessment. In this work, attention is focused on two analyses: The first is a Principal Component Analysis (PCA) study that investigates the correlation between AE data and other SHM data, such as in situ temperature, pendulum displacement, and AE rate. The second analysis corresponds with numerical finite element (FE) studies that assess damage in the base of the tower. Initially, the Smeared Cracking material model is used to understand which zones of the tower are more damaged. Moreover, a possible critical scenario due to increasing tower tilt is investigated. Finally, a viscoelastic formulation of the materials at the base of the tower is used to account for creep to understand the possible viscous effects at the base of the tower. Full article

Background: Experimental animal models remain central to burn research and soft-tissue reconstruction/repair, but method heterogeneity compromises reproducibility, comparability, and translation for depth/area endpoints. Objective: We aimed to map burn-induction methods and examine reproducibility, intentional depth modulation, wound-area stability, validation, and operator-dependent variability. Methods: A PRISMA-ScR review, informed by JBI guidance, was conducted without registration but with predefined questions, criteria, and charting domains. PubMed/MEDLINE, Scopus, Web of Science, Embase, and Google Scholar were searched from inception to 30 January 2026. Eligible studies were English peer-reviewed full-text original in vivo animal studies. Two reviewers independently screened records; one charted data, another checked it. Evidence was mapped by modality, exposure-control architecture, validation, and operator-sensitive steps. Results: Studies varied by species, modality, device design, exposure settings, and severity verification. Modalities were contact, scald, steam, and radiant/infrared. Wound area was more reproducible than depth, which depended on temperature, duration, force/pressure, geometry, equilibration, anatomical site, and assessment timing. Histopathology was the main standard, sometimes complemented by morphometry, optical, or perfusion techniques. Operator-sensitive variability involved force, alignment, contact stability, template integrity, exposure geometry, source stability/environmental control. Conclusions: Burn induction is a measurement-system problem; constraining operator-sensitive variables, predefined validation timing, and quantitative variability reporting may improve validity, comparability, and translation. Full article

Accurate intraocular pressure (IOP) assessment is essential for glaucoma diagnosis and follow-up. Conventional contact tonometry (e.g., Goldmann and rebound devices) remains widely used, but its accuracy is affected by operator dependence, alignment errors, and patient discomfort. We present a non-contact IOP estimation framework based on corneal stress birefringence and full-field fringe inversion. Ex vivo porcine corneas were imaged under controlled pressure loading from 15 to 20 mmHg, and a coupled stress-optic/shell mechanics model was used to generate pressure-indexed synthetic fringe fields for inverse fitting. In the 15–18 mmHg range, more than 75% of the estimates were within plus or minus 1 mmHg of the reference pressure; performance declined at 19–20 mmHg, consistent with a stronger nonlinear biomechanical response and reduced fringe separability. Defect experiments further showed that local stiffness loss caused both near-defect distortion and far-field stress redistribution, supporting the need for full-field rather than point-wise analysis. These results indicate that stress-birefringence imaging is a promising route toward non-contact, region-sensitive IOP assessment. Full article