Search Results (1,253)

Low-cost bipolar-junction-transistor (BJT) thermal pixel arrays provide robust, force-free contact sensing for tactile skins, but their slow frame rate confines contact-timing resolution to the inter-frame interval—252 ms at the 4 Hz rate of the 16 × 16 array studied here—well below the needs of contact-aware control. We propose a four-frame complementary-error-function (erfc) template, derived from one-dimensional semi-infinite heat conduction, that jointly estimates the contact amplitude, the thermal-diffusion parameter, and the sub-frame contact-onset offset (τ₁), solved by a grid-initialized semi-analytic Levenberg–Marquardt scheme (Path A) at deterministic single-pass cost. On 42 contacts from five subjects, the per-contact Cramér–Rao lower bound for τ₁ is 16.2 ms, and the empirical cross-contact dispersion is 83.5 ms; both are internal, model-derived quantities, since no synchronised external timing reference was available. A two-layer rejection pipeline separates 19/19 valid contacts from 2/2 hardware faults; transfers to four held-out subjects (23/23) without retuning; attains an overall AUC of 0.878 on a five-class synthetic disturbance library—ramp and saturating-exponential remain acknowledged failure modes; and rejects 5/6 disturbance trials in a real-airflow stress session. Larger independent cohorts and externally synchronised timing validation remain parameters for future work. Full article

Maintaining a constant frequency is vital for grid stability and reliability, especially during dynamic changes in load and generation, which are caused by the increasing incorporation of renewable intermittent energy sources such as solar and wind power. These energy sources decrease the system’s inertia, which compromises the primary frequency regulation, a process historically sustained by the speed regulators of conventional synchronous generators. In this study, to mitigate this issue, we investigate a battery energy storage system (BESS) operating with virtual synchronous machine (VSM) control to provide ancillary services of primary frequency control. A multilevel cascade H-bridge static converter with eleven levels is controlled to emulate the dynamic behavior of a conventional synchronous machine, allowing primary frequency control support. The case studies are evaluated using Matlab/Simulink R2024a software and tested under contingency scenarios involving load rejection and step-load insertion within an isolated power grid comprising other synchronous machines, alongside an analysis of the BESS-controlled power dispatch. Our simulation results demonstrate that the energy storage system, operating under a virtual synchronous machine (VSM) strategy, effectively emulates the dynamic behavior of a conventional synchronous generator, enabling controlled active and reactive power dispatch. Furthermore, the proposed control strategy provides virtual inertia support, mitigating the Rate of Change of Frequency (RoCoF) following disturbances, improves the damping of frequency oscillations, and ensures a smoother frequency recovery after load variations. These findings indicate that the proposed BESS can provide effective primary frequency control support in power systems characterized by a high penetration of converter-interfaced renewable energy sources. Nonetheless, further investigations into the influence of VSM parameters on the system’s dynamic response are needed to further optimize the performance of the proposed solution. Full article

As calibration errors have a direct impact on epipolar consistency, rectification accuracy, and metric 3D reconstruction performance, stereo camera calibration is a fundamental requirement for high-accuracy 3D modeling and reliable digital twin data acquisition. Because current calibration workflows (based on pairwise calibration methods) lack systematic data-quality checks mechanisms, there is a clear need for more robust data selection strategies. The novelty of the approach consists in the development of a new outlier-aware stereo calibration algorithm (OutAw) that introduces a unified multi-stage approach that integrates hard geometric selection, candidate subset generation, multi-criterion ranking, bootstrap stability analysis, and triangulation assessment into a comprehensive and systematic calibration framework. Unlike conventional approaches, OutAw (through its mechanism of detecting and rejecting inconsistent pairs) redefines the calibration strategy from arbitrary to criterion-based data selection. Also, the proposed algorithm is compared with BSC (a baseline OpenCV all-pairs calibration algorithm) and InterFil (an intermediate filtered variant) using 49 stereo pairs (at 1280 × 720 resolution) captured using a planar checkerboard. OutAw algorithm achieved (using only nine image pairs) superior results (epipolar error 0.5119 px, stereo RMS 0.7666 px) to the BSC ones (epipolar error 1.3687 px, stereo RMS 1.9385 px), representing statistically significant improvements (60.5%, respectively 62.3%). OutAw geometric consistency was validated by triangulation-based metrics (square-length standard deviation 0.1140 mm and square absolute error 0.1097 mm). Contamination analysis revealed that as the outlier rate increases, the calibration process degrades progressively. Also, the results obtained highlight that geometric quality-driven image selection is critical for achieving a reliable stereo calibration for DT applications. Full article

Conventional defect inspection for warp-knitted lace relies on manual work and negative-sample-based training, resulting in low efficiency, frequent false detections and poor adaptability. This study presents a novel AI visual inspection system centered on positive-sample learning, which is built upon a five-layer 5G + Industrial Internet distributed architecture. Supported by modified looms, high-precision imaging devices and an optimized YOLOv5s model, the system accomplishes intelligent defect detection. A positive-sample self-learning paradigm and dual-model collaboration mechanism are proposed to reduce the demand for negative samples and cut labeling expenses. The integration of CBAM, FPN + PAN structure, self-supervised learning and hybrid loss further strengthens the recognition performance for subtle defects under complex patterns. Industrial tests show that the system reaches a grid-level classification accuracy of 95% and a frame-level detection rate over 98%, with a detection speed of 30 m/min. It reduces labor costs and product reject rates by 40% and 30% correspondingly while running stably in real production. This method breaks the constraints of traditional training modes, provides a scalable intelligent solution for the digital upgrading of the warp-knitted lace industry, and promotes the high-quality development of textile manufacturing. Full article

Refugees identifying as lesbian, gay, bisexual, transgender, queer, and intersexual (LGBTQI) may experience discrimination not only prior to and during flight but also within the host country, including stigmatisation by other refugees. Such experiences can severely affect mental health, making LGBTQI refugees a particularly vulnerable group. To date, however, quantitative data on homonegativity within refugee populations remain scarce. In this cross-sectional survey, 70 adult refugees in Germany reported interpreter preferences across three everyday settings. Homonegativity was operationalised as the consistent rejection of an LGBTQI-identifying interpreter across all settings. Sixteen participants (22.9%) showed consistent rejection. This proportion exceeds estimates of negative attitudes towards homosexuals reported for the German general population. Consistent rejection was associated with higher religiosity and was more common among participants who identified as Muslim, with higher rates among refugees from Syria compared with those from Afghanistan. No significant associations were found for age, gender, or length of stay. While the majority of participants did not reject LGBTQI-identifying interpreters, a substantial minority did so consistently. These findings underscore the importance of considering subgroup-specific preferences in interpreter assignment practices and indicate potential risks of discrimination against LGBTQI refugees within shared accommodation settings. Full article

This study aimed to improve the mechanical integrity of Styrofoam membranes fabricated from post-consumer food packaging. To this end, 3D-printing byproduct—thermoplastic polyurethane (TPU) waste—was blended with polyimide (PI) in the membrane dope solution. The synthesized flat-sheet upcycled membranes were evaluated via scanning electron microscopy (SEM), water contact angle (WCA), and tensile testing, while separation efficiency was determined through bovine serum albumin (BSA) rejection and permeation trials. Findings indicate that incorporating TPU into the Styrofoam/PI matrix increased tensile strength by 50%, BSA rejection by 12.4%, and permeation by 33%. Compared with pristine Styrofoam membranes, tensile strength and BSA rejection improved by 240% and 46%, respectively. Although the blend membranes exhibited a reduction in water flux (from 214 to 162.5 LMH/bar) due to pore contraction, they maintained high rejection rates (~86%) for large macromolecules like PVP (1300 kDa). Furthermore, while all membranes remained hydrophilic, hydrophobicity scaled with TPU concentration. Full article

Thermal regulation of lithium-ion (Li-ion) battery modules is a critical constraint for electric vehicle (EV) safety and durability, particularly during high-C-rate operation. Phase change materials (PCMs) have emerged as promising passive solutions due to their latent heat storage capability; however, current literature is heavily biased toward organic paraffin-based systems and lacks structured benchmarking across PCM categories and integration architectures. This review provides a systematic comparative assessment of PCM-based battery thermal management systems (BTMSs) comprising organic, inorganic, and eutectic materials under EV-relevant discharge conditions. The review is structured according to the conventional classification of PCMs; however, the available literature is predominantly focused on organic materials, particularly paraffin-based PCMs, leading to greater depth of analysis for this category. Thermophysical properties are analyzed in conjunction with discharge rate, module configuration, and hybrid cooling strategies. The results indicate that peak temperature mitigation is weakly correlated with latent heat magnitude when thermal conductivity remains below critical values. Conductivity-enhanced composites incorporating expanded graphite or metal foams significantly improve heat diffusion, reducing hotspot intensity and inter-cell temperature gradients under medium-to-high C-rates. Pure passive PCM systems exhibit thermodynamic limitations during sustained high-power operation due to saturation effects, underscoring the need for hybrid architectures for continuous heat rejection. This work establishes a structured benchmarking framework and demonstrates that effective thermal conductivity, integration strategy, and discharge-dependent design dominate BTMS performance over latent heat alone. The findings also reveal that inorganic and eutectic PCM-based BTMSs remain comparatively less explored in the literature, particularly at the battery module level and under realistic electric vehicle operating conditions, highlighting opportunities for future research. Full article

Objective: Preanalytical errors account for the vast majority of preanalytical incidents and remain a fundamental threat to the reliability of test results. Although the types and frequencies of these errors have been extensively studied in the literature, their time-dependent variability has received comparatively little attention. This study aimed to evaluate how preanalytical specimen rejection rates vary across intraday time intervals and to assess the independent influence of time on preanalytical quality. Methods: This retrospective observational study included a total of 579,845 specimens accepted by the central laboratory of Istanbul Atlas University Hospital between January 2024 and December 2025. Specimens were analyzed with respect to preanalytical rejection reasons, the distribution and rate of these reasons across clinical units, and time of day. Each day was divided into six equal four-hour intervals: Z1 (00:00–04:00), Z2 (04:00–08:00), Z3 (08:00–12:00), Z4 (12:00–16:00), Z5 (16:00–20:00), and Z6 (20:00–24:00). Statistical analyses were performed using the Pearson chi-square test, and effect sizes were quantified using Cramér’s V coefficient. Results: Of the 579,845 specimens examined, 4365 were rejected, yielding an overall rejection rate of 0.79%. Rejection rates were found to be non-uniformly distributed across the day (p < 0.001). The highest rejection rate was observed during the Z2 interval (04:00–08:00) at 1.98%, whereas the lowest was recorded during Z3 (08:00–12:00) at 0.45%. Negative binomial regression analysis identified the Z2 interval as the only time period independently associated with an increased rejection risk Incidence Rate Ratio (IRR) = 1.63; 95% Confidence Interval (CI): 1.22–2.19. Among clinical units, the highest rejection rate was recorded in the emergency department (1.92%). Analysis of error types revealed that the majority of rejections were attributable to hemolysis (47.5%) and clotted specimens (26.3%). Hemolysis rates peaked in the emergency department, while clotted specimens occurred more frequently within intensive care units. Analysis of time and error interactions revealed that clotted specimens peaked during Z1 and Z2, whereas hemolysis became the primary cause of rejection during Z3 and Z4. Conclusions: Preanalytical specimen rejection rates exhibited significant variation according to time of day, clinical unit, and error type, with time emerging as a factor independently associated with preanalytical quality. The coexistence of elevated rejection risk during Z2 (04:00–08:00) and markedly low rejection rates during Z3 (08:00–12:00) indicates that the relationship between workload and error frequency is not linear. Although hemolysis and clotted specimens constituted the dominant error types, their distribution followed distinct patterns depending on the clinical unit and time interval. These results underscore the necessity of time-based monitoring to pinpoint unit-specific risks, providing a clear roadmap for targeted quality improvement interventions. Full article

This study produced and analyzed composite membranes composed of polysulfone (PSf), polyvinylpyrrolidone (PVP) and Metal–Organic Framework (ZIF-8) for treating effluent generated by the Batik industry. The incorporation of ZIF-8 was performed to enhance membrane efficiency. The findings indicated that ZIF-8 markedly enhanced hydrophilicity and pure water flux of membranes. The M-0.5 membrane containing 0.5 g of ZIF-8 demonstrated superior performance, with a water contact angle of 49.4° and a porosity of 83.5%. In contrast, the ZIF-8-free membrane (M-0) displayed a water contact angle and porosity of 66.3° and 76.7%, respectively. These combined characteristics enabled the M-0.5 membrane to achieve the highest pure water flux of 197.1 L m⁻² h⁻¹ at 5 bar. All membranes attained complete total suspended solids (TSS) rejection at 100% efficiency. Turbidity rejection rates ranged from 75% to 92%, whilst color rejection rates ranged from 65.7% to 87.6%. The maximum chemical oxygen demand (COD) rejection observed was 57.9%, achieved by the M-0.25 membrane (0.25 g of ZIF-8) at an operational pressure of 4 bar. Meanwhile, for permeability and hydrophilicity, the ideal loading is 0.5 g of ZIF-8 (M-0.5). This concentration yielded the optimal equilibrium of porosity (83.5%), the minimal water contact angle (49.4°), and the maximal pure water flux (197.1 L m⁻² h⁻¹). Nonetheless, the TDS rejection rate was rather low at 8.0–21.1%. The membrane effectively preserved effluent pH stability between 7.9 and 8.3. The aggregation of ZIF-8 at elevated concentrations diminished mechanical strength and selectivity. Additional optimization is required to equilibrate these performance indicators. Full article

This work presents an experimental comparison of three speed control strategies for a permanent magnet DC (PMDC) rover actuator implemented on a resource-constrained embedded microcontroller platform. The system operates under fixed-rate discrete control with quantized encoder velocity feedback, representative of low-cost embedded systems. The controllers evaluated are a classical PID, a PID controller designed via discrete pole placement, and a Mamdani fuzzy controller. Beyond conventional tracking and transient response metrics, the proposed evaluation framework incorporates jerk-based kinematic indicators to assess the mechanical activity induced by control actions under both nominal and mechanically disturbed operating conditions. Experimental validation was performed over a range of operating speeds using repeated trials, and the observed differences were evaluated through nonparametric statistical testing. The results show that controller rankings depend strongly on operating conditions: the classical PID provides smoother motion under nominal conditions, whereas the fuzzy and compensated PID controllers achieve superior disturbance rejection when external mechanical perturbations are introduced. These findings reveal a clear tradeoff between mechanical smoothness and tracking robustness, and demonstrate that controllers exhibiting better tracking performance do not necessarily produce the smoothest kinematic response. The principal contribution of this work is the experimental demonstration that jerk-based indicators provide essential complementary information to conventional performance metrics for the evaluation and selection of embedded speed controllers in mechatronic systems subject to variable mechanical loading. Full article

We compare classical and modern regression models for next-day cryptocurrency forecasting on 14 USD-denominated coins across three liquidity tiers from 2018 through 2025, and we use the resulting panel to formally test three pre-specified hypotheses. The features are a strictly past-only 28-element set; the evaluation uses expanding-window walk-forward cross-validation with nested hyperparameter tuning, stationary block-bootstrap 95% confidence intervals, and pairwise Diebold–Mariano tests. Methodologically, we derive a bias-variance bound that turns the ‘no model beats the mean’ observation from a null finding into a predicted outcome under weak-form market efficiency. Empirically, (H1) the threshold–effect interaction is not supported (slope −1.7 × 10⁻⁴, 95% CI [−4.8 × 10⁻⁴, +1.4 × 10⁻⁴], p = 0.25). (H2) Statistical loss minimisation is decoupled from risk-adjusted economic outcome: the cluster-bootstrapped 95% CI for the Spearman rank correlation between the within-ticker MAE rank and within-ticker post-cost Sharpe rank is [−0.39, +0.10] overall, lies *strictly below zero* on the mid-cap (CI [−0.71, −0.04]) and long-tail (CI [−0.26, −0.09]) tiers, and decisively rejects perfect alignment (ρ = +1) on every tier. None of the seven (ticker, model) pairs with annualised Sharpe ≥ 0.5 has a hit rate significantly different from 0.5; high-Sharpe outcomes reflect return skew, not directional skill—formally predicted by a closed-form Sharpe–MSE decoupling proposition we derive in Section 3.6 under non-zero return skewness. (H3) Lo–MacKinlay variance ratio tests show top-tier coins are indistinguishable from a random walk (|z| ≤ 1.5 at q ∈ {2, 5, 10}), while mid- and long-tail tiers reject the random-walk null at q = 2 (z = −2.36, z = −2.60). The findings extend across two robustness layers. An AR(1)-GARCH(1,1) baseline produces R² ≈ −0.005 on every tier and is indistinguishable from Lasso, supporting the bias-variance bound; Giacomini–White conditional predictive ability tests reject equal predictive ability between Lasso and tree-based models on every coin in every tier, complicating naive DM interpretations; and a forward-walking 2026-Q1 holdout—83 daily observations per coin entirely outside the training window—confirms that H1 is even more decisively null on unseen data and that the H3 efficiency conclusion holds. Together, these results give a formally tested EMH-style picture for daily crypto: no model meaningfully forecasts log-returns; statistical accuracy and trading P&L are decoupled by an analytically derived mechanism; and weak-form efficiency is approximately satisfied in most liquid coins and in the convergence across the cross-section. Full article

Persistent microplastics contaminate wastewater systems and pose significant environmental and human health risks due to their small size, buoyancy, persistence, and diverse physicochemical properties, which reduce the effectiveness of conventional treatment technologies. Freeze crystallization, indirect freeze crystallization, eutectic freeze crystallization, and ice-templated separation have emerged as promising long-term technologies for microplastic removal. Particle rejection at the solid–liquid interface, heterogeneous ice nucleation, brine channel formation, and particle entrapment within advancing ice fronts are key crystallization mechanisms governing microplastic separation. Microplastics can adhere to or nucleate growing ice crystals, according to lab and field research. These interactions influence crystal growth kinetics and ice structure formation. Indirect freeze crystallization (IFC) and related chemical-free crystallization systems offer lower energy requirements and improved scalability. Crystallization processes concentrate microplastics for downstream treatment, may connect with photochemical or oxidative degradation at ice interfaces, and are useful in cold areas or low-temperature industrial streams. Despite these advances, several challenges remain, including freezing rate, salinity, particle size distribution, and surface weathering, which are difficult to control. Integrating crystallization into wastewater treatment systems is also difficult. This review covers the latest advances in microplastic–ice interactions, crystallization engineering, and freeze-based separation technologies. It also highlights major knowledge gaps and suggests future research to use crystallization to remove microplastics from wastewater in a sustainable, scalable, and energy-efficient manner. Full article

This study reports a hierarchically structured quasi-three-dimensional (quasi-3D) hydrogel/feather fabric composite evaporator, with MXene integrated as the photothermal material, fabricated via an in situ freeze–thaw and mechanical interlocking strategy. Benefiting from the rational quasi-3D structural design, the evaporator effectively retains the intrinsic facile weaving and assembly advantages of textile substrates, while addressing the poor mechanical stability and disordered water transport channels inherent to conventional hydrogels. The synergistic coupling between the low-evaporation-enthalpy hydrogel network and vertically oriented feather yarns expands the channels for light reflection and absorption, thereby synergistically enhancing light harvesting, thermal regulation, water transport, and salt rejection. The as-prepared evaporator exhibits a light absorption efficiency of 97.6% and an evaporation rate of 2.13 kg m⁻² h⁻¹ under 1 sun illumination, while sustaining stable performance over 15 consecutive days of outdoor operation. The incorporation of a foam support layer further facilitates effective heat localization and self-flotation, effectively mitigating thermal losses. This work demonstrates an efficient, flexible, and scalable solar evaporator with great potential for sustainable freshwater production. Full article

Background: Renal cell carcinoma (RCC) accounts for nearly 90% of kidney cancers. Transplantation is the best treatment for kidney failure, associated with improved survival, quality of life, and lower societal costs compared with remaining on dialysis. Thanks to modern immunosuppression, rejection rates have decreased. Cancer is the second most common cause of morbidity and mortality in kidney transplant recipients (KTRs) after cardiovascular disease. KTRs are at increased cancer risk due to chronic immunosuppression. Case report: We report a 54-year-old kidney transplant recipient without prior history of malignancy who developed metachronous bilateral RCC early posttransplant (first RCC within 3 months after kidney transplantation and second RCC after one year later). Both tumours were treated with nephrectomy. Conclusions: Early diagnosis enabled appropriate oncologic management while preserving graft function. It should also be stressed that beside graft assessment, abdominal sonography should not be forgotten in kidney allograft recipients, in particular, in certain high-risk patients (i.e., elderly, male, with longer dialysis vintage, smokers, obese, with high burden of immunosuppression including pretransplant immunosuppressive therapy, induction at transplantation, etc.). Full article

Bone loss in the maxillofacial region arises from multiple causes, including periodontal disease, trauma, surgical procedures, infection, congenital anomalies, and cancer. Traditional treatment relies on bone grafting, either alone or in combination with biomaterials. Advances in tissue engineering have introduced synthetic or natural scaffolds to mimic the mineralized bone matrix. Natural scaffolds offer excellent biocompatibility and similarity to native tissue but often lack sufficient mechanical strength and exhibit poor degradation rates. Synthetic scaffolds provide tunable porosity and mechanical stability; however, their biological inertness makes them poor sources of osteogenic signaling. A key factor in the success of any scaffold is its interaction with the host immune system. Upon implantation, the innate immune response is initiated, with neutrophils and macrophages being the first cells to contact the scaffold. Macrophage polarization toward proinflammatory (M1) or anti-inflammatory (M2) phenotypes determines whether the microenvironment favors inflammation or remodeling. The adaptive immune response also plays a critical role: T and B lymphocytes may promote tolerance and integration through Th2/Treg pathways and antibody-mediated regulation, or they may trigger chronic inflammation and rejection through Th1/Th17 activation. This review examines the natural and synthetic materials used for bone remodeling and their biological properties. It then outlines the sequence of immune events occurring from the moment a scaffold is implanted to its potential integration or failure. Finally, this study highlights the relevance of cellular models and in vitro assays for the early evaluation of immunogenicity and biocompatibility, which are essential for optimizing scaffold design and improving outcomes in maxillofacial bone regeneration. Full article