Search Results (23,963)

A polyurethane coating represents the conventional solution for protecting and finishing visible wooden furniture surfaces. However, the increasing use of additive manufacturing has introduced visible 3D-printed polymer components whose surface mechanical performance is relevant to their application in furniture. This study investigated the effect of short-term exposure to 60 °C for 1 h on the surface mechanical properties of a pigmented polyurethane coating applied to oak wood and 3D-printed PLA, ABS-T and PET-G components. Specimens were evaluated under laboratory conditions (20 °C) and immediately after exposure to 60 °C, while their surfaces remained at an elevated temperature. Impact resistance, abrasion resistance, and scratch resistance using a tungsten carbide tip were determined according to the relevant standards, and the surface damage was assessed by visual inspection and digital microscopy. The polyurethane coating exhibited the smallest impact indentation diameter but showed earlier crack initiation and lower abrasion resistance than the 3D-printed polymers. Among the investigated polymers, ABS-T provided the most balanced combination of impact resistance, abrasion resistance and surface hardness, whereas PLA exhibited the greatest dimensional changes after exposure to 60 °C. Microscopic analysis revealed surface defects that were not detectable by visual inspection, demonstrating the value of digital microscopy for detecting subtle surface damage. The results indicate that ABS-T is a promising material for visible furniture components exposed to short-term elevated temperatures, while PET-G should be used with caution in applications exposed to radiant heat or direct sunlight. Full article

In recent years, forest fires have occurred frequently, and extremely high temperatures can easily cause plastic deformation of buried pipelines. To clarify the temperature-stress variation law of natural gas pipelines under wildfire action, this study, based on heat transfer theory and using the finite element method, constructs a numerical model of a buried pipeline and analyzes the thermo-mechanical sequential coupling behavior of the pipe–soil system. It elucidates the influence patterns of key factors such as burial depth, outer diameter, internal fluid pressure, soil thermal conductivity, and fire duration on the temperature-stress fields of the pipe and surrounding soil and investigates pipeline deformation under fire. The results show that burial depth is the most sensitive factor: when it increases from 0.2 m to 0.8 m, the maximum pipe temperature decreases from 291.4 °C to 32.4 °C, and the maximum von Mises stress decreases from 507 MPa to 236 MPa. Furthermore, increasing pipe outer diameter and soil thermal conductivity both exacerbate pipe temperature rise and stress accumulation. Meanwhile, the longer the duration, the more pronounced the soil heat storage lag. Additionally, when internal pressure increases from 2 MPa to 8 MPa, the pipe’s maximum stress increases by up to 10.8%. The analysis results can provide a theoretical basis for identifying high-risk pipeline sections and guiding route selection and protective measure optimization for pipelines crossing forested areas. Full article

This study addresses the unclear damage mechanisms of TiAlSiN-coated tools during high-speed milling of GH4169 by integrating milling experiments with finite element simulations, and establishes a thermo-mechanical coupled damage prediction model that accounts for the superposition effect of cyclic loads. Cutting experiments show that with increasing cutting speed, the rake face damage evolves from peeling and abrasive wear to comb-shaped thermal cracks, mechanical cracks, and large-area peeling, accompanied by a significant reduction in tool life. Simulations reveal that the superposition of residual thermal compressive stress during the idle-cutting phase with mechanical stress in the subsequent cutting cycle forms alternating loads, which is the fundamental cause of thermo-mechanical fatigue crack initiation. The XFEM-CEM coupled model indicates that at higher cutting speeds, the maximum principal stress increases, promoting easier coating crack initiation and greater interfacial debonding. The thermo-mechanical coupled damage prediction model, improved by incorporating a temperature-modified strength threshold and a thermal acceleration factor, yields predictions consistent with experimental results, providing a theoretical basis for process parameter optimization and tool life prediction. Full article

This study evaluated the effects of the methyl methacrylate (MMA)-containing adhesive primer Visio.link on the surface characteristics of sandblasted poly(ether ether ketone) (PEEK) and its bond strength to four dental resin cements: the MMA-based resin cement Super-Bond EX (SB) and the composite-based resin cements RelyX Universal Resin Cement (RX), G-CEM LinkForce (GC), and Panavia V5 (PA). Sandblasted PEEK specimens were tested with or without primer application. Surface morphology, surface roughness, and surface free energy were evaluated, and shear bond strength (SBS) was measured after 1 day of water storage and after 20,000 thermal cycles. Primer application smoothed the sandblasted surface, reduced surface roughness, increased the polar component, and decreased the dispersive component and total surface free energy. Primer application significantly increased the initial SBS of RX, GC, and PA; however, thermal aging reduced bonding durability and caused pretest debonding in several groups. For SB, primer application did not significantly affect the initial SBS, whereas the sandblasted group showed significantly higher SBS than the primer-treated group after aging. The effect of the MMA-containing primer therefore depended on resin cement type and aging condition. These findings suggest that primer application should be considered according to the composition and bonding mechanism of the resin cement rather than routinely incorporated into PEEK bonding procedures. Full article

Public buildings play a critical role in national decarbonization strategies and green energy transitions due to their high energy consumption densities, large occupant capacities, and potential to drive public awareness. Optimizing energy efficiency in these structures not only alleviates the financial burden on public budgets but also serves as a benchmark for sustainable urban development. To investigate the energy-saving potentials, thermal comfort dynamics, and financial feasibilities within this sector, this study selects two university buildings from two different countries with distinct climatic, structural, and operational profiles as comparative case studies: university buildings in Türkiye (TR) and Italy (IT), respectively. A total of seven tailored retrofitting scenarios were developed based on country-specific legislative frameworks and subsidy mechanisms: the Minimum Environmental Criteria (CAM) and Conto Termico 3.0 for Italy, and the Public Buildings Energy Efficiency Project (KABEV), Energy Performance Contracting (EPC), and Nearly Zero Energy Buildings (NSEB) mandates for Türkiye. The scenarios evaluate deep building envelope insulation, high-efficiency window replacements, lighting automation (LED with daylighting controls), mechanical ventilation with heat recovery units (HRV), air-to-water heat pump integrations, and rooftop photovoltaic (PV) installations using calibrated DesignBuilder simulation models. The quantitative results demonstrate that country-specific green building incentives drastically enhance both the energy performance and financial viability of deep retrofits. For the Turkish case study, the comprehensive near-zero energy building (nZEB) retrofitting package (TR-4) successfully reduced annual primary energy consumption by 75% (from 284 to 71 kWh/m²·year) and cut annual thermal comfort discomfort hours by 72% (from 3147 to 880 h), yielding a Subsidized Net Present Value (NPV) of +310,600 €. Similarly, for the Italian case study, the holistic retrofit combined with rooftop photovoltaic integration (IT-4) achieved an 80% energy reduction (dropping from 128 to 25.6 kWh/m²·year), minimized annual discomfort hours to 45 h, and generated a Subsidized NPV of +425,500 €. Furthermore, national incentive mechanisms shortened simple payback periods by more than half, establishing that targeted public policy is vital to accelerate public sector building decarbonization while ensuring long-term fiscal profitability. Full article

The Newton Downhill Optimizer (NDO) provides a compact derivative-free search framework, but its random dimension mask, uniform treatment of individuals, and limited use of supplementary global-best candidates may restrict performance on high-dimensional problems. This study proposes an Enhanced Newton Downhill Optimizer (ENDO) that incorporates three mechanisms: an adaptive dimension mask, a DE/rand/2-based greedy mutation for inferior individuals, and dynamic-boundary opposition-based best guidance. ENDO was evaluated on the CEC2017 benchmark at 10, 30, 50, and 100 dimensions. The primary comparison involved nine representative optimizers, and an additional 100-dimensional comparison was conducted with six advanced optimizers. In the primary 100-dimensional tests, ENDO ranked first on 18 of 29 functions, remained among the top three on 26 functions, and achieved an average rank of 1.79. In the additional comparison, ENDO ranked third with an average rank of 3.52. Across the four dimensions, its average ranks were 1.79, 1.66, 1.38, and 1.79, indicating stable performance under changes in problem scale. ENDO was further applied to a 168-dimensional thermal–pumped-storage economic dispatch problem, where it achieved the lowest mean operating cost, the best average rank of 1.87, and a feasibility rate of 100% over 30 independent runs. Statistical analyses further supported the competitiveness of ENDO across the benchmark and engineering evaluations. These results show that ENDO improves the sustained search capability of NDO and provides competitive performance for complex high-dimensional and constrained optimization problems. Full article

Waterborne polyurethane (WPU) has emerged as one of the most promising environmentally friendly coating materials owing to its low volatile organic compound (VOC) emissions, excellent film-forming ability, good adhesion, and versatility in formulation. However, WPU suffers from several intrinsic limitations including inadequate thermal stability, modest mechanical strength, poor flame retardancy, and a lack of inherent antibacterial activity. To address these deficiencies, phosphorylated microfibrillated cellulose (PMFC), prepared from beech wood sawdust via sequential steam explosion, phosphorylation, and superfine grinding, was employed as a substrate for in situ silver nanoparticle (AgNPs) synthesis and subsequent incorporation into WPU via aqueous blending and solvent casting. PMFC functions through a combined mechanism: the hydroxyl and phosphate groups coordinate Ag⁺ ions, providing nucleation sites, while the nanofibrillar network provides steric stabilization against post-synthesis aggregation. The influence of AgNPs loading (1–10 wt% relative to PMFC at a fixed 1 wt% PMFC content) on the morphology, antibacterial activity, silver release behavior, thermal stability, flame retardancy, and mechanical properties of the resulting composite films was comprehensively investigated using free-standing composite films as a model system. At the optimal Ag loading of 5 wt%, the composite exhibited strong antibacterial activity against Escherichia coli with silver release below 1.15 ppb after 96 h, while tensile strength and Young’s modulus increased by 80% and 298%, respectively, relative to neat WPU. At high Ag loadings (70–80 wt%), the composites achieved conductive-level surface resistivity (~3 log Ω) through percolation network formation, demonstrating antistatic functionality. This study provides an effective strategy for fabricating WPU composite films with combined antibacterial, mechanical reinforcement, and antistatic capabilities. Full article

Advanced engineering applications increasingly demand high-performance polymers with exceptional mechanical and thermal properties; however, predicting their processing behavior remains challenging due to complex rheological responses and the lack of integrated experimental–simulation frameworks. This study introduces a novel integrated experimental–computational methodology that combines comprehensive rheological characterization, multi-model fitting, injection molding simulation, and multiphysics finite element analysis (FEA) to investigate the processing capabilities of Polyether Ether Ketone (PEEK) for aircraft bearing applications. Unlike conventional approaches that treat rheological analysis, processing simulation, and structural assessment separately, our framework establishes a coupled material–process–performance relationship through: (i) systematic thermal and mechanical characterization, establishing PEEK’s high melting temperature (343 °C), degradation temperature (575 °C), and tensile strength (95 MPa); (ii) comparative rheological model fitting, demonstrating that the Carreau–Yasuda model accurately predicts non-linear flow behavior with R² = 0.97, outperforming simpler Power Law and Cross models; (iii) CAD-based injection molding simulation, revealing homogeneous flow distribution and optimized pressure profiles; and (iv) thermo-mechanical FEA, coupling thermal expansion with structural stress analysis to evaluate bearing integrity under operational conditions. The key novelty lies in the seamless integration of experimental rheology with multiphysics simulation, validated through rigorous statistical analysis achieving low RMSE (0.6854 MPa for stress, 0.003220 mm for deformation) and high correlation coefficients (R² = 0.97). The results confirm a uniform flow distribution, stable structural performance, and reliable thermo-mechanical response, establishing PEEK’s suitability for high-performance aerospace components. This work contributes a comprehensive, scalable, and transferable framework that bridges experimental analysis and advanced simulation, enabling the predictive optimization of polymer processing parameters and significantly enhancing manufacturing reliability for industrial applications. The findings demonstrate the applicability of the experimental–computational analysis to the investigated PEEK bearing configuration under the specified processing and simulation conditions. Its specific contribution is the application of comparative rheological model fitting and experimentally characterized PEEK properties to the selected bearing geometry and processing conditions. Full article

Laser powder bed fusion (LPBF) enables fabrication of complex bimetallic structures, such as combustion chambers, that require a thermally conductive internal liner supported by a high-strength structural jacket. Inconel 625 (IN625) served as the substrate, with GRCop-42, a Cu-Cr-Nb alloy developed by NASA Glenn Research Center, deposited with varying laser powers and laser scanning speeds to create the IN625–GRCop-42 interface. Hot isostatic pressing (HIP) was performed to evaluate defect mitigation, and Vickers microhardness testing was conducted to assess the mechanical properties across the bimetallic interface. Microstructure characterization revealed porosity across the full processing window and, along with density measurements, we were able to establish that the HIP treatment was unsuccessful in eliminating the defects, indicating that densification is primarily achieved by LPBF process optimization. Microhardness testing showed that the as-printed samples showed higher microhardness values than the as-HIPped samples due to the fine microstructure, high dislocation density and residual stresses caused by the LPBF process. The decrease in microhardness following HIP suggests that recrystallization, grain coarsening and residual stress relief may have occurred during post-processing. These results highlight the importance of LPBF process optimization in achieving strong, thermally stable IN625–GRCop-42 bimetallic interfaces. This study investigates the microstructural and mechanical behavior of the IN625 and GRCop-42 dissimilar metal interfaces fabricated using the LPBF process and the effects of HIP on the bimetallic microstructure. Full article

Wildfire in African savannas reflects coupled surface thermal, hydroclimatic, vegetation, and disturbance processes, but basin-scale time-series analyses can overstate mechanisms when temporal dependence and spatial heterogeneity are ignored. We assembled a monthly 2003–2024 multi-source environmental dataset for the Zambezi River Basin ($n=263$) and nine Level-4 HydroBASINS units, using quality-controlled MODIS burned area, normalized difference vegetation index (NDVI), daytime land surface temperature (LST), and evapotranspiration (ET), together with CHIRPS precipitation and GLDAS-2.1 Noah 0–10 cm soil moisture. Primary inference used heteroskedasticity- and autocorrelation-consistent regressions, expanding-window Random Forest validation, false-discovery-rate-controlled distributed-lag tests, and sub-basin robustness; vector autoregression was retained as a secondary diagnostic. Current-month burned-area anomalies were positively associated with LST ($\beta =0.340$, $p=0.0015$) and negatively associated with near-surface soil moisture ($\beta =-0.326$, $p=0.0005$). Over 1–9 months, precipitation and soil-moisture histories were jointly supported after multiplicity correction, whereas basin-wide NDVI, ET, and LST histories were not. Burned-area history was followed by cumulative 0–6 month declines in NDVI ($\beta =-0.280$, 95% CI $[-0.452,-0.107]$) and ET ($\beta =-0.214$, 95% CI $[-0.419,-0.008]$). Directions were broadly consistent across sub-basins, although magnitudes varied. The evidence supports time-scale-specific conditional associations without structural-causal claims. Full article

Planetary sample return missions can impose extreme mechanical forces on both spacecraft and the returned samples collected from a planetary surface that they contain. The chain of custody phases from entry/descent/landing to curation each present distinct vibration, shock, and dynamic loads that may compromise sample integrity. Interplanetary sample return missions, from the Apollo program to Stardust, Hayabusa, Hayabusa2, and OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, and Security—Regolith Explorer), have refined capsule design to ensure sample integrity. While much attention has understandably been paid to contamination control, thermal control, and mechanical shock at impact, the role of vibrational monitoring on the sample container itself is less frequently explored; yet, it merits attention. Here, we combine a review of vibration sensor aspects relevant to planetary sample return with a Monte Carlo analysis of how capsule-level vibration may propagate into representative lunar sample types. Using Apollo-derived sample container geometries and a representative multi-frequency capsule vibration environment, we show that sample archetypes can exhibit substantially different dynamic responses to the same vibration input. These results illustrate the value of vibration measurements at or near the sample container for documenting the mechanical environment experienced by returned material and interpretation of potential scientific losses during transport and curation. Full article

Chrome-containing corundum–spinel castables are the preferred materials for ladle purging plugs due to their excellent slag resistance, high mechanical strength, and good volume stability. However, their poor thermal shock resistance often leads to transverse cracking or thermal spalling, thereby limiting their service life improvement. Since aggregates typically constitute 70 wt% of castables, modifying the aggregates may be an effective strategy to enhance the thermal shock resistance. To this end, alumina spherical aggregates were prepared via a pan granulation technique using α-Al₂O₃ powders as the raw material and a ZnCl₂ solution as the binder. The effects of the firing temperature on the physical properties and the microstructure of the as-fabricated aggregates were investigated, followed by an evaluation of their impact on castable performance. After firing at 1400 °C for 3 h, the resulting alumina spherical aggregates exhibited a porous interior and a dense exterior structure, with an apparent porosity of 27.21%, a water absorption capacity of 9.38%, and a crushing rate of 51.3%. When these aggregates were incorporated into castables, their apparent porosity increased, while the bulk density and the cold strength showed slight reductions; however, their thermal shock resistance was notably improved. Among the formulations tested, the castable containing 4% of 0.2–0 mm spherical aggregates exhibited the best thermal shock resistance, with a residual strength of 7.96 MPa and a strength retention rate of 27.85%. Full article

Background/Objectives: Sjögren’s Syndrome (SS) is an autoimmune disorder with impaired exocrine gland function. Its pathogenesis remains elusive, but aberrant innate/adaptive immunity and dysregulated interferon signaling are core features. Current SS research lacks exploration of innate immune mechanisms and therapeutic targets. Phloretin, a natural dihydrochalcone derivative, inhibits excessive innate immune activation, yet its role and mechanism in SS remain unreported. Methods: This study aimed to explore the therapeutic efficacy of phloretin against Sjögren’s syndrome (SS) and elucidate the regulatory mechanism underlying its effects on dendritic cells (DCs) and the Stimulator of Interferon Genes (STING)-driven innate immune cascade. Clinical specimens were utilized to analyze DC infiltration and STING expression in the labial glands of SS patients. In vivo experiments were conducted on NOD/Ltj SS mice with phloretin treatment, using hydroxychloroquine as a positive control. For in vitro studies, DCs were stimulated with poly I:C to verify the functional effects of phloretin and its regulatory role in the STING/TANK-binding kinase 1 (TBK1)/Interferon Regulatory Factor 3 (IRF3) signaling. Salivary secretion, glandular inflammatory responses, and systemic immune overactivation were evaluated in SS mice. In poly I:C-stimulated DCs, cell activation, migration, and co-stimulatory molecule expression were measured. The regulatory effects of phloretin on the STING signaling cascade and STING ubiquitin-mediated degradation were examined by Western blotting. Phloretin, initially identified as a candidate compound via virtual screening, was subjected to thermal shift assay (CETSA), drug affinity responsive target stability (DARTS) and molecular dynamics simulation (MD) for direct binding verification with STING. The STING overexpression rescue experiment further corroborates that phloretin modulates innate immune responses in a STING-dependent manner. Results: Clinical results revealed obvious infiltration of CD11c⁺STING⁺ DCs and CD11c⁺p-TBK1⁺ DCs in labial gland lesions of SS patients. In NOD/Ltj SS mice, phloretin treatment recovered salivary secretion, relieved glandular inflammatory injury, and restrained excessive activation of innate and adaptive immune responses, showing comparable therapeutic effects compared with hydroxychloroquine. In vitro experiments confirmed that phloretin could alleviate poly I:C-induced abnormal activation and migration of DCs, as well as reduce the expression of co-stimulatory molecules. Mechanistically, phloretin was found to interfere with the STING signaling cascade, alter the ubiquitination level of STING protein, and further inhibit the abnormal activation of DCs, which may contribute to its protective effects against Sjögren’s syndrome. Notably, results from MD, CETSA and DARTS collectively validate the interaction between phloretin and STING protein, providing solid molecular-level evidence for its regulatory effect on STING signaling transduction. Conclusions: DCs and STING-driven innate immunity critically contribute to SS progression. Phloretin effectively ameliorates SS-related immune disorders by restraining DC overactivation and STING signaling, supporting it as a promising candidate agent for SS treatment. Full article

Compared with bare copper wire, palladium-coated copper (PCC) wire is widely used in microelectronic packaging due to its improved oxidation resistance and enhanced reliability. However, the formation mechanism of free air balls (FABs) and the redistribution behavior of Pd during the electronic flame-off (EFO) process, particularly under different Pd coating thicknesses and processing conditions, have not yet been fully understood. In this work, four types of 1 mil PCC wires with Pd coating thicknesses of 60, 80, 100, and 120 nm were systematically investigated to study the influence of EFO parameters on FAB morphology and Pd redistribution behavior. SEM, FIB, and EDS analyses were employed to provide experimental insights into the coupled relationship between transient thermal input, internal pore distribution and elemental segregation evolution, and Pd redistribution behavior. The results show that the preferred FAB morphology is obtained at 54 mA and 580 μs, with a diameter-to-wire ratio of approximately 2. With increasing Pd coating thickness, the exposed copper area on the FAB surface decreases from 13% to 6%, while the Pd-deficient region gradually shifts toward the bottom of the FAB. This study provides experimental insights into the Pd redistribution behavior during FAB formation under different EFO conditions, which may contribute to the optimization of Pd-coated Cu bonding wires. Full article

Bag-in-box (BiB) wine packaging is increasingly used for export, but conditions inside palletised units are rarely measured directly. We instrumented 3 L BiB units with in-bag MEMS pressure and temperature sensors during a 20-day static chamber trial using 19 °C and 50 °C set-point chambers, labelled C19 and C50. The set-point labels do not represent measured wine temperatures. A 15-day single-stack verification trial was also run at the C50 set point. In the main trial, the measured in-bag temperature differed strongly from the chamber set point. C50 packages stabilised at 34.2 ± 0.4 °C in the top units and 26.1 ± 0.2 °C in the bottom units, while C19 units remained around 22.8–23.5 °C. In the verification trial, individual sensors reached 45.0–48.8 °C, but no in-bag sensor reached 50 °C. Internal pressure rose after handling and peaked between day 3 + 13 h and day 5 + 19 h. Bottom-position units showed a larger uncorrected peak ΔP than top-position units (adjusted difference: 20.4 mbar; F(1,8) = 9.14; p = 0.017). The position result is interpreted as exploratory. The pressure analysis used a small unbalanced sensor-level design, with one missing bottom-position C19 trace, no barometric reference logger, and no retained stack pairings. Bulk wine from C50 showed lower free and total SO₂ and higher volatile acidity than wine from C19. Lactic acid was significantly higher in C50, although the underlying mechanism could not be established and residual microbial activity cannot be excluded. Overall, chamber set points were a poor proxy for actual in-package conditions. Selected sentinel packages can document real thermal and pressure exposure in palletised BiB wine. Full article