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Science Centres as Metacognitive Learning Environments: Insights From Eye‐Tracking and Metacognitive‐Oriented Worksheets
No full textBackground: Informal science learning environments, such as science centres, provide unique opportunities for students to engage in conceptual understanding through interactive and multimodal experiences. However, without structured support, student engagement may remain superficial in those environments. To help students engage in activities in science centres, such support can be provided through metacognitive regulation activities that play important roles in promoting deeper learning. Although these internal processes are difficult to observe, eye-tracking technologies and metacognitive-focused worksheets (MoWs) may offer promising ways to externalise and analyse students' self-regulatory strategies in real-world settings.Objectives: This study aimed to explore how MoWs in combination with mobile eye-tracking technology support and monitor metacognitive engagement and conceptual understanding of 7th grade students during collaborative learning in science centres. The study focused on three scientific topics: work and energy, mirrors and light absorption and the solar system and beyond.Methods: Using a multiple case study design, data were collected from 72 seventh grade students participating in peer-to- peer collaborative learning sessions at two different science centres. Data sources included recordings from eye-tracking sessions, video observations and student-generated responses on MoWs. A multimodal data triangulation approach was used to identify metacognitive behaviours aligned with the orientation, planning, monitoring and evaluating phases. Coding schemes were developed and refined through iterative analysis of gaze data, verbal discourse and behavioural indicators.Results: The findings suggest that MoWs can support students in these specific settings to activate prior knowledge, plan in real time and collaboratively monitor and evaluate their own learning. Monitoring was the most frequently observed metacognitive behaviour, followed by orienting and evaluating. Eye-tracking data revealed shared patterns of visual attention, gaze synchronisation and strategic information processing during collaboration. Students' correct use of scientific concepts also varied across subjects. The highest accuracy was observed in the solar system and beyond unit, while the highest misunderstandings were found to be related to mirrors and light absorption.Implications: This study demonstrates the value of integrating MoWs and eye-tracking technology as learning and analytical tools to support and analyse students' metacognitive regulation in informal learning settings. The findings provide practical insights for designing structured yet flexible learning activities that encourage deeper cognitive engagement and promote conceptual understanding in science education. The study also attempts to make a methodological contribution to the field by proposing a gaze-based framework for assessing metacognitive processes in authentic, collaborative learning environments.</p
An investigation into the analyte-dependent fluorescence quenching of BaTiO₃ nanoparticles for the fluorimetric determination of glucose and paracetamol
No full textThis study investigates the synthesis, characterization, and application of barium titanate nanoparticles (BaTiO₃ NPs) as a fluorimetric sensing platform. Nanocrystalline BaTiO₃ particles, exhibiting quasi-spherical morphology with average diameters evolving from approximately 7 to 9 nm depending on reaction time, were successfully prepared via a room-temperature chemical synthesis route. Comprehensive characterization using techniques such as XRD, SAED, TEM, FTIR, and UV–Vis spectroscopy confirmed the formation of a polycrystalline perovskite structure and elucidated the material's morphological and optical properties. The synthesized BaTiO₃ NPs displayed stable, intrinsic fluorescence, optimally emitting at 467.42 nm upon excitation at ∼402.33 nm in a neutral pH environment (pH 7). This fluorescence was observed to be effectively quenched by multiple analytes, including glucose and paracetamol, establishing a basis for the development of a sensor. Quantitative analysis revealed analyte-dependent quenching efficiencies, with Stern-Volmer studies indicating glucose as the most potent quencher among those kinetically analyzed. The system demonstrated sensitive detection capabilities, achieving low parts-per-million (ppm) limits of detection (LOD) for both glucose (∼1.19 ppm) and paracetamol (∼1.04 ppm). Notably, the linear dynamic response range varied significantly, extending up to ∼1.8 ppm for glucose but reaching at least 3.6 ppm for paracetamol. The demonstrated fluorescence stability, coupled with sensitive and analyte-dependent quenching responses, highlights the potential of these BaTiO₃ nanoparticles as a versatile and robust material for developing future fluorimetric sensors
Novel application of reinforcement learning for adaptive user clustering in LEO NTN systems: comparative analysis with traditional benchmarks
No full textThe demand for global connectivity is driving the development of low Earth orbit (LEO) Non-Terrestrial Network (NTN) systems, which offer low latency but face dynamic channel conditions. Efficient user scheduling plays a pivotal role in multi-user multiple-input multiple-output (MU-MIMO) downlink systems, as it enables the maximization of spatial multiplexing gains while effectively mitigating inter-user interference. This user selection problem is NP-hard, particularly as the number of users vastly exceeds the number of available antennas on the LEO satellite, making an exhaustive search for the optimal cluster computationally intractable. Conventional scheduling methods, such as graph-based or heuristic approaches, are hindered by high computational complexity and poor adaptability to network dynamics. This paper introduces a novel reinforcement learning (RL) framework for dynamic user scheduling. The approach utilizes proximal policy optimization (PPO) and soft actor-critic (SAC) to optimize cluster assignments and sizes, balancing throughput, fairness (modeled via SINR variance minimization), and cluster count. An SINR-based initialization enhances learning efficiency. Simulations demonstrate that SAC achieves superior throughput, while PPO excels in fairness and operational efficiency. Both significantly outperform baseline methods (K-means, K-means without SINR initialization, and Random-based), providing a scalable and adaptive solution for next-generation non-terrestrial networks
An integrated computational approach for AI-assisted BIM analytics and digital twin development
No full textFluid–CO₂ injection in a hypersaline volcanic systems: a reactive transport and experimental evaluation with application to the Tuzla Geothermal Field, Türkiye
No full textThis study evaluates the CO2 sequestration capability of the Tuzla Geothermal Field (TGF) in northwest Türkiye under reservoir conditions (200 °C and 4.4 MPa). While ongoing studies at TGF have investigated CO2 co-injection primarily for geothermal heat extraction, the present study focuses on the associated potential for long-term CO2 storage. To this end, CO2–brine–rock interactions were examined through batch reactor experiments and reaction path modeling using the PhreeqC geochemical tool. The experiments revealed complex dissolution/precipitation reactions that altered reservoir properties, with mineralogical analyses (XRD, XRF, SEM, and EDS) showing the formation of secondary phases such as calcite, kaolinite, and Ca-rich aluminosilicates. These results indicate that the Tuzla reservoir rocks provide sufficient divalent cations to support mineral trapping under reservoir conditions. Overall, our findings highlight that, in addition to its promise for heat extraction, CO₂ co-injection at TGF offers an opportunity for permanent geological storage, thereby strengthening the dual benefits of this approach
Measurements of the inclusive W and Z boson production cross sections and their ratios in proton-proton collisions at TeV
No full textMeasurements are presented of the W and Z boson production cross sections in proton-proton collisions at a center-of-mass energy of 13.6 TeV. Data collected in 2022 and corresponding to an integrated luminosity of 5.01 fb−1 with one or two identified muons in the final state are analyzed. The results for the products of total inclusive cross sections and branching fractions for muonic decays of W and Z bosons are (acceptance) nb for W+ boson production, (acceptance) nb for W− boson production, and (acceptance) nb for the Z boson production in the dimuon mass range of 60–120 GeV, all with negligible statistical uncertainties. Furthermore, the corresponding fiducial cross sections, as well as cross section ratios for both fiducial and total phase space, are provided. The ratios include charge-separated results for W boson production (W+ and W−) and the sum of the two contributions (W±), each relative to the measured Z boson production cross section. Additionally, the ratio of the measured cross sections for W+ and W− boson production is reported. All measurements are in agreement with theoretical predictions, calculated at next-to-next-to-leading order accuracy in quantum chromodynamics
Plasmon-enhanced ultrabroadband optical limiting performance of colloidal and thin film silver nanowires
No full textOptical limiting materials are essential for the innovation of optoelectronic devices and human eyes in defense industry. The two most important parameters for an ideal optical limiter are the optical limiting spectral range and a low optical limiting threshold value. Herein, silver nanowires (Ag NWs) were examined in both colloidal dispersion and as thin films embedded within a polymethyl methacrylate (PMMA) matrix to evaluate their optical limiting performance across an ultrabroad wavelength range. PMMA polymer, which does not exhibit nonlinear absorption, was used to reveal the nonlinear optical property of Ag NWs. For this purpose, the nonlinear optical response of colloidal and thin film Ag NWs was investigated using the open aperture Z-scan technique, under varying excitation wavelengths and input intensities using a femtosecond pulsed laser system. To gain deeper insight into the underlying mechanism of nonlinear optical behavior, ultrafast pump–probe spectroscopy measurements were conducted. Open aperture Z-scan experiments revealed that both colloidal and thin-film AgNWs exhibit similar nonlinear optical behavior under excitation wavelengths ranging from 400 to 800 nm with increments of 100 nm. Moreover, to analyze nonlinear absorption properties in near infrared region, experiments were also carried out using pulsed laser excitation at 1200 and 1600 nm. Among the excitation wavelengths studied, 1600 nm located in the longitudinal mode of surface plasmon resonance of Ag NWs produced the highest βeff value. This enhancement was attributed to multiphoton absorption and plasmon-enhanced excited-state absorption (ESA) processes. Under 1200 and 1600 nm excitation, the colloidal Ag NW dispersion exhibited reverse saturable absorption (RSA) signals superimposed on saturable absorption (SA) behavior, in contrast to the thin-film form, where only RSA was observed. Across the ultrabroadband excitation range of 400-1600 nm, the optical limiting performance exhibited threshold values ranging from 0.02 to 0.33 J/cm2, indicating wavelength-dependent nonlinear absorption behavior. This work is among the first to systematically investigate Ag NW based optical limiters over an ultrabroad excitation range extending from the visible to the near-infrared (400–1600 nm). Overall, Ag NWs in both colloidal and thin-film forms exhibited ultrabroadband optical limiting responses, highlighting their potential for photonic and optoelectronic applications
