Medium frequency transformers (MFTs) have emerged as a key enabling technology in medium voltage (MV) power electronics systems, supporting applications such as solid state transformers (SST), power electronic traction transformers (PETT), medium voltage direct current (MVDC) power distribution. This review provides a comprehensive overview of high-power MFTs, focusing on their state of the art, applications, technical challenges, and current research solutions. The paper surveys key considerations including core materials, core shapes, winding technologies, winding structures, insulation considerations, dielectric materials, electric field stress grading materials, and cooling technologies. Specifically targeted at modern MV power electronics, this paper discusses the challenges and solutions in MFT insulation design and test. The topics include complex voltage stress and electric field distribution, partial discharge under medium frequency high dv/dt waveforms, and insulation test standards which are critical to enhance the performance, reliability, and development of high-power MFTs in MV applications.

Mitochondrial dysfunction contributes to poor embryo quality and recurrent assisted reproductive technology (ART) failure. Mitochondrial transplantation (MIT), which involves supplementing oocytes with exogenous mitochondria, has been proposed as a novel strategy to improve ART outcomes. However, both its clinical efficacy and safety remain unclear. In this single-center trial, 151 patients with a history of ≥ 2 failed ART cycles provided 1178 metaphase II (MII) oocytes. Sibling oocytes were randomized 1:1 to receive autologous bone marrow mesenchymal stem cells (BMSCs) mitochondria co-injection during intracytoplasmic sperm injection (ICSI) or standard ICSI. The primary outcome was the rate of day-3 good-quality embryos. MIT significantly accelerated early embryonic cleavage at the 3-cell stage and 5-cell stage, but this morphokinetic alteration did not translate into improvements in good-quality embryo rate, clinical pregnancy rate, or live birth rate. Long-term follow-up of 23 live births revealed no adverse effects, with all offspring exhibiting normal growth and development. Exploratory analysis revealed that oocytes yielding ≥ 70% transferable embryos after MIT harbored an elevated higher burden of medium frequency (0.05-0.5) mtDNA point mutations. While autologous BMSCs-MIT transiently alters early cleavage kinetics, it does not demonstrate a clinical advantage in unselected patients with recurrent ART failure. Nevertheless, its observed safety profile and the identification of mtDNA mutation burden as a potential predictive biomarker provide a foundation for shifting future MIT research from a universal approach toward precision application in molecularly stratified populations. Trial registration ClinicalTrials.gov registration: NCT03639506.

Eco-engineered Fe3O4@cellulose@APTES nanocomposites as efficient dye-sensitized solar cell counter electrodes: Electrochemical analysis and photovoltaic performance.

Objective: This cross-sectional study investigated whether the frequency of waking-state and sleep-related bruxism is associated with sensitivity to occlusal tactile stimuli (i.e., occlusal tactile acuity) in healthy individuals. Methods: Forty healthy participants (20 females and 20 males) completed the Oral Behavioural Checklist to assess the frequency of waking-state and sleep-related bruxism. Participants were stratified into groups representing low, medium, and high bruxism frequency. Occlusal tactile acuity was evaluated using articulating foils of different thicknesses (8–56 μm) and sham trials presented in random order. Each stimulus was tested six times. Participants indicated whether they perceived a foil between their teeth. Signal detection theory was applied to distinguish perceptual sensitivity from response strategy. Results: Detection accuracy increased with foil thickness. Individuals with a high frequency of sleep-related bruxism exhibited reduced detection of thinner foils (8–24 μm) compared with those with low frequency of sleep-related bruxism (p = 0.029). Additionally, participants with high-frequency waking-state or sleep-related bruxism were more reluctant to report occlusal contact, indicating a more conservative reporting strategy (p = 0.045 and p = 0.002, respectively). Conclusions: Higher frequency of sleep-related bruxism was associated with reduced detection of low-intensity occlusal stimuli and a more conservative reporting strategy. These findings indicate an association between sleep-related bruxism frequency and differences in occlusal tactile detection. However, as the bruxism assessment was based on self-reports, these findings should be interpreted with caution.

This paper systematically studies the characteristics of building vibration and structural noise caused by train operation in view of the vibration and noise problems specific to the railway canopy complex in the integrated development of stations and cities through field measurement. The results show that the vibration energy of the floor slab is concentrated in the medium and low frequency band of 20-80 Hz and directly leads to the main peak of indoor noise in the 40-80 Hz band, with significant coherence between the two, confirming that the “vibration-sound” coupling mechanism is the main source of noise; Interior decoration can effectively improve the acoustic environment quality by reducing the reverberation time. This study reveals the intrinsic connection between vibration and noise and demonstrates that “vibration control of sound” is the fundamental approach to addressing such problems. The research results can provide key theoretical basis and engineering guidance for the optimal design and environmental control of the superstructure.

Understanding how fish generate thrust across diverse swimming gaits is central to bio‐inspired robotics. Here, we combine particle image velocimetry (PIV), system identification, and simulation to uncover the hydrodynamic mechanisms underlying swimming of a modular robotic fish (µBot). By modulating motor frequency, µBot exhibited two distinct gaits: a low–medium frequency traveling‐wave “fish‐like” gait shedding two pairs of vortices per cycle, and a high‐frequency standing‐wave “resonant” gait shedding double rows of single vortices of opposite sign per cycle. PIV revealed that thrust in the resonant gait is dominated by tail pressure (reactive), whereas such pressure contributions are negligible in the traveling‐wave gait with thrust primarily generated by drag forces (resistive). We developed an analytical model incorporating reactive and resistive force components and identified its parameters using genetic algorithms to fit experimental data. The fitted model reproduced swimming speed and body kinematics with high accuracy and revealed gait‐dependent variations in hydrodynamic parameters. Sensitivity analyses confirmed that only a subset of force components influenced swimming performance. Finally, energetic analyses showed resonance behavior in standing‐wave gait but not in traveling‐wave gait. This integrative framework highlights the distinct roles of reactive versus resistive forces across gaits, advancing the design and control of efficient fish‐inspired robots.

ABSTRACTBackgroundThree‐dimensional (3D) MR elastography (MRE) derives viscoelastic parameters that may reflect inflammation, but their frequency dependence and the influence of steatosis on inflammation grading and fibrosis staging remain unclear.PurposeTo investigate 3D multifrequency MRE for assessing hepatic inflammation, fibrosis stage across frequencies, and the influence of steatosis.Study TypeProspective.PopulationSixty‐four (40 men, median age: 58 years) participants with chronic liver disease (CLD); 21 (8 men, median age: 28 years) healthy volunteers.Field Strength/Sequence3‐T; gradient‐echo sequence with mechanical vibrations at low (16.7 and 18 Hz), medium (33.4 and 36 Hz), and high (50.1 and 54 Hz) frequencies.AssessmentIn CLD participants, MRE‐derived viscoelastic parameters, shear stiffness, storage modulus, loss modulus, and damping ratio were compared with histologically assessed fibrosis, inflammation, and steatosis. MRE test–retest repeatability over 10 min was evaluated in healthy volunteers.Statistical TestsWilcoxon rank sum test, Spearman's correlation, multivariable regression analysis, and area under the receiver operating curve (AUROC). A p value of < 0.05 was considered statistically significant.ResultsInflammation was significantly independently associated with damping ratio at medium frequency, which showed moderate performance for grading inflammation (AUROC = 0.76–0.83, sensitivity = 0.83–0.84, specificity = 0.70–0.79). Fibrosis staging using shear stiffness and moduli showed high diagnostic performance (AUROC = 0.82–0.95), with comparable accuracy between medium and high frequencies (p = 0.327–0.896). Steatosis was not significantly correlated with MRE overall (p = 0.212–0.459), but was significantly associated with 19% higher stiffness and 20% higher loss modulus at medium frequency in CLD participants without fibrosis or inflammation.Data ConclusionMedium frequency 3D MRE demonstrated an independent association with inflammation while preserving accurate fibrosis assessment. Steatosis seemed not to confound MRE‐based evaluation.Level of Evidence1.Technical EfficacyStage 2.

The magnetic components made of thin laminated silicon steels are viable candidates to work within the medium frequency range, and are often exposed to the power electronic rectangular voltage excitations. The related energy loss of thin laminated silicon steels produced in that context should be predicted accurately and efficiently. However, the traditional loss models, for instance Steinmetz equations, are empirical in nature, thus requiring a lot of experimental data to extract their coefficients. Contrarily, the numerical loss models are prohibitively time-consuming. In this paper, a fully analytical loss model for sinusoidal excitations is firstly derived by applying the Statistical Theory of Losses (STL) and the fractional derivatives for the classical eddy current loss component. Then the relation between sinusoidal excitation loss and rectangular excitation loss of duty cycle 0.5 is constructed. Thereby, a pure analytical loss model of laminated silicon steels for rectangular voltage excitations with arbitrary duty cycle is developed with the concept of separately treating the positive and negative parts of this kind of excitation. Finally, the predicted losses of two laminated silicon steel samples under the rectangular voltage excitations with different duty cycles by our proposed model, complex permeability model and Improved Generalized Steinmetz Equation (IGSE) are compared with the measured ones, verifying the superiority of the proposed model, and only a few data measured under normal sinusoidal excitations are needed to identify it.

In medium voltage and medium frequency application scenarios, <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LLC</i> converters with high-power insulated gate bipolar transistor (IGBT) modules are favoured as a dc-dc transformer (DCX) to provide unregulated bus voltage due to their cost-effectiveness and soft-switching advantages. Dead time is a critical parameter in ensuring that the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LLC</i>-DCX converter operates in zero voltage switching (ZVS) mode. However, since the turn-off behavior of high-power IGBTs is strongly affected by the dynamic charge stored in the N-base region during the conduction phase, traditional dead time design methodologies are no longer suitable for the above application requirements. To address this issue, this paper first proposes a simplified time-domain analytical expression for the resonant current of the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LLC</i>-DCX converter. A dead time design methodology is then developed that combines the turn-off behavior of high-power IGBTs with the proposed resonant current expression. This methodology incorporates the effects of dynamic charge stored in the N-base region during the conduction phase and gate driver parameters to improve the accuracy of dead time calculations for ZVS operation of <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LLC</i>-DCX converters. Finally, the proposed methodology is validated using an 8 kW <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LLC</i>-DCX converter. Compared with the existing methods, the proposed method reduces the difficulty of solving the resonant current in the time domain and improves the accuracy of the dead time calculation of the ZVS operation.

Although prior research indicated that indoor ventilation might have supported mental health in older adults, evidence remained scarce for those with disabilities, who represented a particularly vulnerable population. This study investigated the association between indoor window ventilation frequency and anxiety symptoms among older adults with disabilities in China using nationally representative data. A cross-sectional analysis was conducted using the Chinese Longitudinal Healthy Longevity Survey. Anxiety symptoms were assessed using a validated scale, and indoor window ventilation frequency was examined across multiple seasons. Multivariable linear regression models were used to evaluate associations. Frequent indoor window ventilation was significantly associated with lower anxiety symptoms. Compared with low frequency ventilation, medium (B = -0.651, 95% confidence interval = -1.119, -0.183) and high (B = -0.793, 95% confidence interval = -1.243, -0.342) frequency ventilation showed stronger protective effects. Seasonal ventilation patterns also demonstrated consistent negative associations with anxiety symptoms. This study added scientific value by identifying a low-cost, environmental strategy to alleviate anxiety in disabled older adults. Our findings called for greater policy attention to indoor ventilation practices, including public awareness campaigns and improvements to living environments to promote mental health in aging populations.

Tropical cyclones (TCs) are discrete events that affect ecology of estuaries. On 26 May 2021, TC Yass (category-1) disrupted the Muriganga estuary (ME), West Bengal coast, India. Authors assessed short-term cyclone-mediated changes of the copepod community by sampling three stations on the ME before and after TC Yass. Copepod and water samples collected on November 2020, and January and April 2021 were assumed as pre-Yass samples. Post-Yass samples were collected between 4 and 22 June 2021 once in every 6 days. It was hypothesized that diversity, total abundance and dominance of the copepods of the ME were impacted by TC Yass. Post-Yass the ME turned polyhaline from its meso-haline characteristic. Post-Yass species richness was higher than the pre-Yass period. Pre-Yass Bestiolina similis was the most abundant species, and species such as Paracalanus parvus and Acartiella tortaniformis co-dominated the copepod community. Post-Yass, Acartiella tortaniformis was the most abundant species of the copepod community followed by Oithona brevicornis and Paracalanus parvus. Post-Yass, total abundance of cyclopoid copepods was higher than the pre-Yass. Spatial heterogeneity of the copepods, which was observed during the pre-Yass was lost in the post-Yass period. Those changes in composition and abundances may have cascading consequences for the ecology of the copepods in the ME. Such changes could be traced through a high frequency sampling (e.g., daily to weekly) starting within the first week of a TC impact followed by a medium (e.g., monthly interval) frequency sampling based on the intensity of a TC, resident time of water in an estuary and the complexity of its copepod community.

Abstract Accurately predicting the charging load of residential electric vehicles (EVs) is crucial for optimizing the power grid and infrastructure planning. In order to reduce the impact of high fluctuation of charging load on prediction results, this paper proposes a hybrid prediction model that integrates enhanced decomposition technology and Conv-Informer network. Firstly, identify key features through Pearson correlation analysis. Then, the fully integrated empirical mode decomposition (CEEMDAN) with adaptive noise is used to perform initial decomposition on the charging load data, obtaining multiple intrinsic mode functions (IMFs). These IMFs are divided into high, medium, and low frequency components based on sample entropy, with the high frequency components further decomposed using variational mode decomposition (VMD) and their modulus optimized using the center frequency method. Input all components into the Conv-Informer model for prediction, where the convolutional layer extracts local load features, the Informer module captures long-term load dependencies, and finally weights and superimposes the predicted values of each subsequence to obtain the final result. Based on real data validation experiments in a residential area in Zhejiang Province, China, the proposed model achieved an RMSE of 5.74 kW and a MAE of 4.03 kW. Compared with other common models, its prediction error has been reduced by about 30% (e.g. LSTM: RMSE=9.28 kW, MAE=6.64 kW; Single Informer: RMSE=7.61 kW, MAE=4.54 kW). It can be seen that the method proposed in this article has good accuracy and stability, and is suitable for predicting the charging load of residential electric vehicles.

Introduction: Gout is a disease that causes pain in the joints caused by the buildup of uric acid crystals. Objective: The purpose of this community service was to improve the understanding of the elderly at the Community Health Service Mugi Sehat Dukuhwaluh. This community service aims to explore and evaluate the impact of gout interventions on the elderly. Method: The way to overcome gout problems in the elderly is to conduct mass counseling for the elderly at Community Health Service Dukuhwaluh with a total of 22 participants. By using the method of presentation, discussion and working on pre test and post test questions with powerpoint slide media and leaflets about gout. Results: The results were that the elderly aged 35-59 years had a frequency of 8 and a percentage of 38%, the elderly aged 60-77 years had a frequency of 13 and the percentage was 62%. The level of knowledge of the elderly pre-test is both 6 and the percentage is 30%, while the pre-test is medium frequency 15 and the percentage is 70%, the level of knowledge in the post test is both 21 and the percentage is 100% while the medium post test has a frequency of 0 and the percentage is 0%. The number of participants who did not have a history of gout arthritis was 14 (66.7) more than those who had a history of gout arthritis 7 (33.3). Conclusion: education of gout arthritis is well organized. Increasing level of understanding of the elderly about gout arthritis.

This study examined whether different levels of cognitive impairment influence postural control (PC) in physically independent older women, using complementary time domain and time-frequency analyses. Understanding these associations may help identify early markers of cognitive vulnerability and guide preventive strategies aimed at reducing fall risk in aging. A cross-sectional sample of 129 women aged ≥ 60 years (mean age 69), physically independent and not engaged in structured exercise for at least three months, was categorized into three groups according to Montreal Cognitive Assessment (MoCA) scores: normal cognition (NC), mild cognitive impairment (MCI), and advanced cognitive impairment (ACI). PC was assessed through time domain variables, mean sway velocity (anteroposterior and mediolateral) and the area of the center of pressure (A-COP), and through time-frequency parameters categorized into low (0.05-0.5Hz; visual-vestibular contribution), medium (0.5-1.5Hz; cerebellar modulation), and high (1.5-10Hz; proprioceptive contribution) frequency bands. Confirmatory analyses for the primary conditions (BSEO and BIUS) were performed using ANCOVA adjusted for age, body mass index (BMI), Charlson Comorbidity Index (CCI), and Falls Efficacy Scale (FES) scores. Exploratory outcomes were analyzed with one-way ANOVA, followed by Sidak-adjusted post hoc tests. Effect sizes were estimated using partial eta squared. Time domain analyses showed that women with better cognitive performance demonstrated better postural control, reflected by lower sway velocity, particularly in the BSEO and BIUS conditions. Exploratory analyses also identified group differences in the BIVR condition. Although the time-frequency analyses did not reveal statistically significant differences between groups, the descriptive patterns suggested that lower-frequency components were more evident during less demanding tasks, whereas medium and high frequency components appeared more prominent in more challenging conditions. Effect-size estimates supported the clinical relevance of time domain differences between cognitive groups. Cognitive status influences postural control in physically independent older women. Time domain measures, particularly sway velocity, were sensitive to poorer balance among those with cognitive impairment, while time-frequency parameters did not differentiate cognitive groups. These findings highlight the importance of incorporating cognitive screening into balance assessment and fall-prevention strategies in aging populations.

We report numerical results regarding the minimum sustaining coil excitation current for a RF-RF hybrid torch operating at two different frequencies. The first coil is excited at a high-frequency, while the second coil is set at a medium frequency. The filling gas is argon, at atmospheric pressure. We use the modeling software COMSOL Multiphysics to describe the evolution of key parameters when: (i) the distance between the two coils changes, (ii) the power of the high frequency coil changes. We discuss the radial temperature profiles, the axial velocities and the heat convected at the end of the medium-frequency coil. The latter is compared with the total heat conduction to the plasma confinement tube wall.

A method is proposed for suppressing uncontrollable noise factors in the form of local variations in the electrophysical properties of the weakly magnetic substrate material of tested objects during eddy current measurements of the thickness of dielectric coatings in the medium frequency range up to 100 kHz. As opposed to methods focused on complicating measuring instruments, in particular the use of multi-frequency techniques, swept-frequencies, resource-intensive numerical techniques for computer-based solution of inverse problems, etc., the new approach to solving this problem involves the use of the Taguchi method for robust parameter design of optimal eddy current probes in terms of improving signal-to-noise ratios, which ultimately ensures minimal variability of the useful signal without actually eliminating uncontrollable interference inherent in the tested objects. This made the medium frequency ECPs competitive for the specified measurements compared to high frequency ones due to the simplification of the hardware part of the gauges, the removal of the problem of equipping them with special sensors, and the reduction of their cost. Because of conducting a variance ANOVA analysis, the statistical influence of the design parameters of thickness gauge probes on the characteristics of the output signal was determined. This enabled the establishment of technical requirements for the accuracy of measuring devices in the manufacturing process, as well as the maintenance of operating parameters, specifically frequency and excitation current, within acceptable limits without significantly compromising the optimal signal-to-noise ratio.

Objective.To quantify differences in quantum noise fraction (QNF) between direct and indirect mammography detectors across spatial frequency bands, assessing the ability of QNF to reveal performance degradation at high frequencies.Approach.QNF of various mammography detectors were analyzed by selectively restricting the analysis to medium and high spatial frequency bands. The study included detectors from different manufacturers, both direct and indirect types. Noise components were determined from the sub-bands of a wavelet packet decomposition applied to uniform images acquired at different entrance kerma levels. The noise components were obtained from the terms of a second-degree polynomial fitted to the total noise variance of the sub-bands as a function of entrance kerma to the detector. The results obtained were compared with detective quantum efficiency calculations and contrast-detail curves of the detectors studied.Main results.The QNF results obtained in the different frequency bands studied differ significantly from those calculated in the image domain. In all cases, the QNF decreases with increasing frequency across the entire range of kerma values. Moreover, this decrease is much more pronounced for indirect detectors than for direct ones. Despite showing similar QNF values in the spatial domain, the differences between direct and indirect detectors become substantial in the mid-frequency bands and increase even further in the high-frequency bands. Among the image quality metrics evaluated, the largest differences between detectors were observed in the frequency-dependent evolution of the QNF.Significance.Decreasing values of the QNF reflect the loss in signal-to-noise ratio transfer from input to output in digital detectors, which is directly associated with a loss in detectability. The greater reduction in quantum noise observed in the mid- and high-frequency components of indirect detectors may indicate a decline in their performance for tasks involving the detectability of small objects. QNF exhibited the greatest sensitivity to scintillator-induced signal blurring, making it the metric that best distinguishes between direct and indirect detector designs.

A method is proposed for suppressing uncontrollable noise factors in the form of local variations in the electrophysical properties of the weakly magnetic substrate material of tested objects during eddy current measurements of the thickness of dielectric coatings in the medium frequency range up to 100 kHz. As opposed to methods focused on complicating measuring instruments, in particular the use of multi-frequency techniques, swept-frequencies, resource-intensive numerical techniques for computer-based solution of inverse problems, etc., the new approach to solving this problem involves the use of the Taguchi method for robust parameter design of optimal eddy current probes in terms of improving signal-to-noise ratios, which ultimately ensures minimal variability of the useful signal without actually eliminating uncontrollable interference inherent in the tested objects. This made the medium frequency ECPs competitive for the specified measurements compared to high frequency ones due to the simplification of the hardware part of the gauges, the removal of the problem of equipping them with special sensors, and the reduction of their cost. Because of conducting a variance ANOVA analysis, the statistical influence of the design parameters of thickness gauge probes on the characteristics of the output signal was determined. This enabled the establishment of technical requirements for the accuracy of measuring devices in the manufacturing process, as well as the maintenance of operating parameters, specifically frequency and excitation current, within acceptable limits without significantly compromising the optimal signal-to-noise ratio.

The conventional implementation of the repetitive control (RC) in the standard 50/60 Hz inverter features fast roll-off of the gain-frequency response (GFR) at the frequency beyond the control bandwidth. Contributed by the high output frequency <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f₀</i> of the medium frequency (MF) applications, the fine reshape of the RC plant at the frequency up to several kilohertz is nontrivial for enhancing the low-order harmonic rejection capability. Therefore, the implementation of RC is revisited from the perspective of structure selection, parameter tuning, and the trade-off between tracking performance and stability. Orienting at double-zero approximation over a wide frequency band, the design criteria and the optimizing principle of RC are elaborated for MF inverter. The plugged-in RC is employed, where the proportional-integral parameters are tuned by constraining the gain of the RC plant lower than 1. A biquad filter in series with the fractional-order zero-phase-shift (ZPS) filter is further used for the 0 dB approximation of the GFR of the RC plant, and the Lagrange interpolation-based phase-lead filter is adopted for 0-degree correction. Moreover, the damped ZPS filter-based internal model effectively avoids the center frequency shift and guarantees a high gain (>30 dB) at selected <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">nf₀</i>. Finally, experiments are conducted on a 600 VA prototype, confirming that the dynamic and steady-state performance of the MF inverter are satisfactory with the implementation of the proposed RC.

Abstract Soda lime silicate glass produced by the float process is among the materials with the largest use worldwide. The manufacturing process introduces an asymmetry in the glass sheets that causes well‐known modifications in terms of properties between the so‐called “air side” and “tin side”. Nevertheless, not much is known about the structural changes induced by the diffusing tin ions in the network. In the present work, we show that surprisingly, the short range of the tin side is akin to that of the bulk, while the network connectivity in the air side vicinity is enhanced with a larger concentration of bridging oxygens. This correlates with a partial depletion of modifiers from the air side as detected by secondary ion mass spectrometry. On the other hand, the incorporation of tin markedly changes the medium range. In fact, the tin side is characterized by: (i) longer correlation distances, (ii) a more homogeneous structure depicted by a more reduced splitting of the medium frequency Raman features into R and R c bands, (iii) a substantially lower amount of free volume, and (iv) a slight reduction in the average free volume size. Furthermore, the spontaneous hydration layer on the two surfaces is studied, and its effect on the free volume is discussed. These results provide new insight into the soda lime silicate glass structure and have various technological implications for processes like chemical tempering or phenomena like surface defects nucleation.