Search Results (23,105)

Although chitosan (CS)- and essential oil (EO)-based packaging systems have been widely reviewed, a focused synthesis connecting nano-delivery design with interfacial regulation, film-network evolution, release behavior, and preservation performance in real food systems remains lacking. This review addresses that gap by examining CS-based nano-delivery systems for EOs in active food packaging, with an emphasis on how carrier design and multiscale organization govern functional performance. Major delivery strategies, including nanoemulsions, nanoparticles, nanogels, Pickering emulsions, nanofibrous systems, and nanocomposites, are discussed in relation to EO stabilization, dispersion uniformity, and controlled release. Their effects on film microstructure, mechanical and barrier properties, thermal stability, optical behavior, and antimicrobial and antioxidant activities are further evaluated alongside preservation outcomes in fruits, vegetables, dairy products, meat, and aquatic products. Particular attention is given to structure-function relationships across the carrier, interface, and film-network levels, and to the distinction between established active-packaging functions and emerging smart-packaging applications. Current challenges include EO compositional variability, limited cross-study comparability, sensory constraints, migration and regulatory concerns, and insufficiently scalable fabrication routes. Future work should prioritize mechanism-informed interfacial design, standardized evaluation frameworks, food-specific release-preservation correlations, and scalable green manufacturing. Full article

Pentagonal NiAs₂ is a low-symmetry two-dimensional material relevant to nanoelectronic and thermoelectric applications, but its low lattice thermal conductivity (κ) may limit heat dissipation in device-related scenarios. In this work, the strain-dependent lattice thermal transport of monolayer penta-NiAs₂ is investigated using first-principles calculations combined with the phonon Boltzmann transport equation. The lattice thermal conductivity increases monotonically with tensile strain. Mode-resolved analysis shows that this enhancement mainly originates from the selective reinforcement of the out-of-plane acoustic ZA branch, rather than from a uniform increase in all phonon branches. Tensile strain weakens low-frequency anharmonicity, suppresses phonon scattering, and prolongs the ZA phonon lifetime. Meanwhile, the modified ZA dispersion increases its group velocity, further enhancing its contribution to heat transport. The reduced group velocities of the TA, LA, and most optical branches further limit their contributions to thermal conductivity. The results reveal a ZA-phonon-mediated mechanism for strain-enhanced thermal transport in penta-NiAs₂ and provide guidance for tuning phonon transport in pentagonal two-dimensional materials. Full article

Interoperability remains a central issue in multi-performance building simulation, where heterogeneous domain-specific tools must be combined despite differences in modeling formalisms, numerical solvers, and execution schemes. Existing approaches, including data exchange standards and component-based frameworks such as the Functional Mock-up Interface (FMI), address specific levels of interoperability but often require model-level access, component wrapping, Functional Mock-up Unit (FMU) packaging, or framework-specific integration. This paper examines service-level interoperability, where domain-specific simulation tools are exposed as autonomous web services coordinated through an external orchestration mechanism. A structured, JSON-based Pivot DataSet (PDS) organizes data exchange between services, while coupling strategies are implemented at the orchestration level to manage interactions without accessing internal model structures. The approach is evaluated using a classroom case study from the Agence Nationale de la Recherche (ANR) COSIMPHI research project, focusing on communication overhead, synchronization constraints, and coupling behavior in distributed co-simulation. Under the investigated weak-coupling conditions, the waveform relaxation method (WRM) reduces synchronization iterations by 144× over one day and by approximately 3319× over one month compared with minute-by-minute sequential chaining. These results, obtained under weak thermal–acoustic coupling conditions, highlight the relevance of service-level interoperability and orchestration-level coupling for distributed building-performance simulation workflows involving independently developed domain tools. Their generalization to stronger coupling regimes, however, remains a direction for future work. Full article

Al-50 wt% Si alloy is widely used in aerospace and electronics but is hard to machine owing to uneven microstructure. To elucidate the relationship between force–thermal coupling effects and surface integrity during Al-50 wt% Si alloy milling, this paper established a stress model to reveal the superposition mechanism of mechanical and thermal stresses. Experiments were conducted to investigate the evolution of cutting forces and temperatures, as well as their influence on surface integrity characteristics, including microhardness, roughness, and chip morphology. The results showed that temperature increases steadily with v_c, whereas cutting force fluctuates in an irregular manner. The maximum cutting temperature rises by 85.04% as v_c increases from 25 m/min to 125 m/min. Meanwhile, the thermo-mechanical coupling effect exerts a regulatory role on chip morphology, where higher v_c improves chip continuity and ductility. Surface integrity is determined by the competitive interplay between work hardening and thermal softening, and the surface microhardness varies from 168.49 HV to 173.27 HV. Specifically, elevated v_c optimizes surface quality, with the Ra decreasing by 24.54%, whereas excessive f_z and a_p aggravate damage. Ultimately, surface defects arise from the combined removal behavior of Si particles and deformation of the Al matrix, while the inhomogeneous stress field induces subsurface damage. Full article

This study investigates the structural sensitivity of a large-span steel space frame at Yanjiao Station to environmental disturbances during the critical “flexible suspension” stage of asymmetric hydraulic lifting. First, by analyzing the offset between the center of mass and the center of stiffness—induced by the asymmetric lifting configuration—the study systematically examines the spatial eccentric amplification effect under a coupled thermal-wind field. To this end, a non-uniform solar radiation model based on the Axis-Aligned Bounding Box (AABB) algorithm is integrated with a refined finite element model, enabling a full-factor parametric analysis under 20 coupled load conditions. The results reveal a significant time lag in the structural temperature field, with 12:00 identified as the critical time for maximum thermal deformation. The wind-induced response follows a “bimodal evolution” pattern, and the maximum translational-torsional coupling effect occurs at wind direction angles of 60° and 120°. Further analysis of the multi-field coupling mechanism indicates that the wind field dominates the deformation mode, while the temperature field amplifies the resulting response. Consequently, the peak displacement reaches 192.50 mm, which represents a 360.81% increase compared to the dead load baseline. The cantilever end is identified as the primary vulnerable region. Based on these findings, a “wind direction–time” two-dimensional monitoring strategy is proposed. This strategy provides scientific quantitative criteria and theoretical support for the construction safety of large-span structures, as well as for the development of a comprehensive early warning and health monitoring system. Full article

Pearlitic wheel steel subjected to thermal–mechanical fatigue (TMF) during braking can undergo catastrophic fracture. This study clarifies the microstructural evolution governing the macroscopic cyclic hardening/softening behavior of pearlitic wheel steel under thermal–mechanical fatigue (TMF) with a constant mechanical strain range of −0.4% to +0.2%. At lower temperature amplitudes (200–500 °C), the geometrically necessary dislocation (GND) density reaches 20.4 × 10¹⁴/m² during initial cycles, corresponding to cyclic hardening due to dislocation pile-ups at cementite lamellae interfaces. With increasing cycles, the GND density decreases to 12.3 × 10¹⁴/m², concurrent with softening arising from lamellar bending/fracture, partial spheroidization, and dynamic recrystallization of ferrite. At higher temperature amplitudes (200–730 °C), the GND density decreases from 8.8 × 10¹⁴/m² to 3.5 × 10¹⁴/m², reflecting sustained cyclic softening dominated by thermally activated mechanisms, including cementite spheroidization and dislocation annihilation. The resulting softened microstructure consists of ferrite grains, intragranular dispersed cementite, and chain-like coarse cementite at boundaries. Unlike previous studies that focused on single loading conditions (e.g., thermal fatigue, rolling contact fatigue, or wear), the present work addresses the more complex TMF scenario and quantitatively elucidates the interplay between mechanical response and microstructural evolution in pearlitic steel. This work provides theoretical guidance for the development of a fatigue life prediction model for pearlitic wheels under braking. Full article

Carbon fiber reinforced epoxy resin composites were manufactured using the vacuum infusion technique. Composite samples were subjected to impact and then exposed to various weathering conditions. Static and dynamic mechanical tests were performed to evaluate the effect of an additional process step, a plasma treatment of the carbon fiber fabric, before the composite is manufactured. Scanning electron microscopy and thermal analysis were used to get further information on the degree of damage after weathering. Treating the reinforcing carbon fibers with air plasma resulted in improved strength values and fatigue behavior of the epoxy resin composite. This performance enhancement persisted even after low-energy mechanical stress and subsequent weathering. Full article

The sealing performance of compressed air energy storage (CAES) caverns represents a multi-physics challenge involving coupled thermal–hydraulic–mechanical processes, characterized by complex interacting factors. As a critical determinant of the long-term operational efficiency of CAES facilities, this study developed a fiber-reinforced cement-based composite sealing material through systematic orthogonal experiments investigating four key parameters: water–cement ratio, sand ratio, fly ash–silica fume content, and basalt fiber content. An optimized mixture was formulated with a water–cement ratio (0.36), sand ratio (42%), fly ash–silica fume content (22%), and basalt fiber content (1.0%). Under this optimal mix proportion, the measured permeability coefficient of the sealing layer is 1.92 × 10⁻¹³ cm/s, and the uniaxial compressive strength and tensile strength are 37 MPa and 3.9 MPa, respectively, with a corresponding elastic modulus of 18 GPa. Meanwhile, the P-wave velocity is approximately 2823 m/s, and the porosity is 0.15, achieving balanced performance in permeability, strength, and porosity. The material was validated in a CAES physical model through gas charge–discharge tests under various operational scenarios for the composite sealing layer-lining-surrounding rock system. Full article

The high sensitivity of HgCdTe infrared detectors makes them highly vulnerable to laser irradiation, yet the influence of pulse width on damage behavior in the short-wave infrared (SWIR) band remains insufficiently understood. In this study, we experimentally and numerically investigate the damage effects of SWIR pulsed lasers on HgCdTe focal plane array detectors, focusing on the role of pulse width. Three lasers with pulse widths of 5.5 ns, 0.6 ms and 2 ms are used to irradiate the detector, and the damage thresholds for spot damage, line damage, and complete failure are measured. Damage morphologies are characterized by optical microscopy and scanning electron microscopy. A finite-element thermal model is also established to calculate transient temperature distributions and theoretical damage thresholds. For the 0.6 ms pulse, the measured thresholds for spot damage, line damage, and complete failure are 5.7 J/cm², 65.4 J/cm², and 157.3 J/cm², respectively; for the 2 ms pulse, these increase to 12.1 J/cm², 149.3 J/cm², and 405 J/cm² due to energy dispersion. Microscopic analysis reveals that spot damage arises from melting of HgCdTe and indium bumps, line damage from partial damage to the read-out integrated circuit (ROIC) layer, and complete failure from melt-through of the ROIC layer. The spot damage threshold of the 5.5 ns pulse is 1.2 J/cm², while neither line damage nor complete failure occurs even with a 352.5 J/cm² laser pulse, indicating different damage mechanisms due to a thermal confinement effect. The simulation results agree well with the experimental observations. These findings clarify the pulse-width dependence of damage thresholds and provide practical guidance for detector hardening and photoelectric countermeasure design. Full article

ZERODUR glass-ceramic is widely used in ultra-precision optical components because of its extremely low thermal expansion and excellent dimensional stability. However, its two-phase microstructure, composed of crystalline and amorphous phases with different mechanical properties, may cause non-uniform material removal during magnetorheological polishing, thereby limiting further improvement of nanoscale surface quality. To address this issue, this study investigates the effect of oxide abrasives on the surface homogenization of ZERODUR. A single-particle abrasive–workpiece contact model based on modified Hertz contact theory and elastoplastic contact analysis was established to compare the indentation responses of CeO₂, SiO₂, and ZrO₂ abrasives in the two constituent phases. Magnetorheological polishing experiments were conducted under identical process parameters, and the polished surfaces were characterized by AFM over scan areas of 2 μm × 2 μm, 5 μm × 5 μm, and 10 μm × 10 μm. The results show that all three abrasives improved the surface quality of the ring-polished substrate, with ZrO₂ achieving the best surface homogenization performance. The lowest roughness, Ra = 0.104 nm, was obtained at a 2 μm field of view, and the ZrO₂-polished surface showed more stable roughness evolution across different scan sizes than the CeO₂- and SiO₂-polished surfaces. These results indicate that the elastic modulus, hardness, and mechanical compatibility of abrasives with ZERODUR play key roles in governing contact stress, indentation behavior, and final surface quality. This work addresses the lack of mechanistic understanding of abrasive-dependent surface homogenization in the magnetorheological polishing of two-phase ZERODUR glass-ceramic. The main innovation is the integration of contact-mechanics-based abrasive–workpiece modeling with multi-scale AFM characterization to clarify how abrasive mechanical compatibility affects nanoscale surface uniformity and to guide abrasive selection for ultra-smooth optical manufacturing. Full article

This work evaluates a high-voltage stacked piezoelectric actuator designed for high force and high power, via silicone oil as both the primary dielectric insulator and thermal management medium. The proposed stacked actuator consists of 10 active lead zirconate titanate (PZT) discs, each 2 mm thick and 50 mm in diameter, wired in parallel and mechanically stacked in series. Quasi-static displacement measurements confirm successful operation up to 2.5 kV/mm with a measured free displacement of 25 µm at 5000 V, in agreement with the constitutive displacement relationship, demonstrating that silicone oil provides effective dielectric insulation at the intended field level. Steady-state thermal measurements across drive conditions ranging from 600 V to 1000 V and 2000 Hz to 5000 Hz show consistent surface temperature reductions of 5 °F to 15 °F with the addition of static silicone oil compared to air. Additional results and discussion are disclosed. Full article

Polymer/Silica aerogel (SA) composites improve mechanical properties strategically, but the mixing process disrupts the aerogel’s structure, reducing its efficiency due to polymer chains filling the pores. Pre-vulcanized natural rubber latex (PVNRL) with a higher crosslink density can strain the moving chains, thereby preserving the SA-porous structure in the bulk composite for thermal insulation materials. This study aimed to investigate the effects of PVNRL pre-vulcanization time and SA-immersion time in PVNRL. For PVNRL/SA composite preparation, various PVNRL, from 0 days to 8 days of pre-vulcanization time, were mixed with a fixed SA content of 20 parts per hundred of rubber (phr) using a latex compounding method. Subsequently, the PVNRL/SA slurries were cast on glass plates with 0, 3, and 6 days to obtain the PVNRL/SA composite. Considering the effect of pre-vulcanization time, the crosslink density of the composite increased and revealed a peak at PVNRL/SA with 8-day PVNRL by 7.277 ± 0.881 μmol , corresponding to the closest percentage of pore area in the SA’s structure to the pristine SA, and eventually a 42.41% lower thermal conductivity than the PVNRL/SA with 0-day PVNRL exhibited. In addition, the thermal conductivity increased more slowly over immersion time with the presence of 8-day PVNRL. The proposed correlation states that increasing the pre-vulcanization improves the thermal insulation performance of PVNRL/SA composites, emphasizing the reduction of filled SA’s pore with unvulcanized NR chains. Furthermore, the PVNRL/SA composite with 8-day PVNRL maintains thermal stability at 387.3 °C, and can be flexed at room temperature. These fascinating discoveries may be advantageous for further applications related to thin-film and flexible thermal insulation materials. Full article

Thermal/environmental barrier coatings (T/EBCs) have become a notable research field for the development of high-performance thermal protection coatings. The mechanical properties are essential for T/EBCs, which determine the functionality, reliability and durability of coatings. The Yb₄Hf₃O₁₂ TEBCs were prepared by atmospheric plasma spraying using nanostructured spherical feedstocks and the nanomechanical properties of the Yb₄Hf₃O₁₂ coatings were characterized by nano-indentation in this work. Results indicate the elastic indentation work (W_e) is 16.06 ± 1.45 nJ and the plastic indentation work is 28.62 ± 6.87 nJ for nanostructured Yb₄Hf₃O₁₂ coatings. The ratio of plastic work to total deformation work during indentation as the energy dissipation parameter (η) is 0.63 ± 0.05 for nanostructured Yb₄Hf₃O₁₂ coatings and it can be preliminarily inferred that the Yb₄Hf₃O₁₂ coating may possess favorable erosion resistance, although direct erosion testing is needed for confirmation. Full article

In the context of global warming, thermal environmental problems in coastal urban ag-glomerations have become increasingly prominent. This study focuses on the urban ag-glomeration around Hangzhou Bay, constructs annual heat island intensity classification maps based on MODIS summer land surface temperature (LST) data from 2000 to 2020, analyzes the spatiotemporal patterns of heat islands, and investigates their driving mechanisms using the Extreme Gradient Boosting and Shapley Additive exPlanations (XGBoost-SHAP) model. The results show that: (1) the high-frequency area of strong heat islands expanded by 62.10% during the study period, extending from early built-up areas to newly developed coastal zones, with the spatial pattern transitioning from point-like distribution to areal agglomeration; (2) significant differences exist between the north and south coasts, where strong heat island center migration on the north coast is consistent with impervious surface expansion, whereas the south coast is significantly influenced by coastal wetland siltation; (3) impermeable surfaces and wind speed are key factors affecting LST, with impermeable surfaces acting as the primary driver of temperature increase, while wind speed plays a significant role in moderating temperatures. This study provides a scientific basis for thermal environment regulation in coastal urban agglomerations. Full article

The food packaging sector widely relies on polymeric materials, and as sustainability concerns grow, commodity polymers need to be replaced with innovative and more sustainable materials. Thermoplastic polyurethane (TPU) is a versatile elastomeric polymer characterized by flexibility, strength, chemical and abrasion resistance, and biocompatibility. However, it presents some limitations, notably in terms of functional properties (such as barrier properties). The use of nano-sized renewable fillers, such as cellulose nanocrystals (CNCs), may improve these properties, extending the applicability range of TPU. In this work, bio-based TPU nanocomposites were obtained by adding commercial silane-modified cellulose nanocrystals (Si−O−CNC) at different contents (1–5 wt.%). The nanocomposites were produced via melt mixing followed by compression molding and were characterized in terms of their chemical (FTIR), morphological, thermal, mechanical, rheological, wettability, and barrier properties (i.e., water vapor permeability, WVP and oxygen transmission rate, OTR). The presence of Si−O−CNC promoted hydrogen-bonding interactions with the TPU matrix, affecting the microphase separation and organization of the hard segments. These microstructural changes improved thermal stability, reduced WVP and OTR, and increased tensile properties at lower nanofiller contents (1–3 wt.%). At higher contents, partial nanofiller aggregation was observed, leading to a reduction in mechanical performance. Overall, these results suggest that TPU/Si−O−CNC nanocomposites have promising potential as sustainable food packaging materials. Full article