Search Results (3,395)

For high-speed compound helicopters, such as the S-97 Raider, the reflection and diffraction effects of vertical/horizontal tails on pusher propeller noise are inevitable. To investigate the noise distortion effect of the rear-mounted pusher propeller, this study first relies on the Chinese Laboratory of Rotorcraft Navier-Stokes (CLORNS) solver, adopting the high-resolution Perturbed polynomial reconstructed Targeted Essentially Non-Oscillatory scheme (TENO-P) combined with the Delayed Detached Eddy Simulation based on the Spalart–Allmaras (SA-DDES) turbulence model to resolve the multi-scale rotor flowfield. Additionally, a continuous and conserved acoustic source extraction method is proposed to eliminate non-physical waves at the one-way Computational Fluid Dynamics and Computational AeroAcoustics (CFD–CAA) coupling interface, addressing the temporal inconsistency between flowfield evolution and acoustic propagation. Finally, numerical investigations are conducted on the instantaneous acoustic wave propagation and acoustic directivity of the pusher propeller under the influence of vertical/horizontal tails. The results show that significant acoustic distortion occurs when pusher propeller-generated noise interacts with vertical/horizontal tails. This interaction not only produces reflected and diffracted acoustic waves but also leads to wavefront discontinuities, the formation of short acoustic waves, and changes in acoustic directivity. The maximum variation in the sound pressure level reaches 10 dB at local azimuths. The distortion effect of tails on pusher propeller noise is closely correlated with the number of propeller blades. The interaction process between the propeller and tails becomes more complex with the increase in blade count, resulting in the generation of shorter acoustic waves. For the six-blade rotor, the originally continuous acoustic wave branch can be split into up to four short waves. This study confirms that the proposed Hybrid Computational AeroAcoustics (HCAA) method holds significant application prospects in the aeroacoustic research of compound helicopters. Full article

Bi-doped low-silver Sn-Ag-Cu solders are increasingly gaining attention in advanced electronic packaging due to their cost-effectiveness and enhanced mechanical properties. However, the thermo-mechanical reliability mechanisms of such modified solders, particularly Sn-0.3Ag-0.7Cu-3Bi (SAC0307-3Bi) within Ball Grid Array (BGA) assemblies, remain insufficiently understood. To address this gap, this research proposes a comprehensive assessment framework integrating constitutive parameter calibration with finite element analysis (FEA) to accurately characterize the mechanical behavior and fatigue durability of SAC0307-3Bi solder joints under cyclic thermal loads. The Anand viscoplastic parameters were first calibrated via the Norton creep law and virtual tensile tests. Subsequently, a 3D quarter-symmetry model was constructed to replicate thermal cycling conditions between 25 °C and 125 °C. Simulation data reveal a strong correlation between stress concentration and the Distance to Neutral Point (DNP), pinpointing the chip-side interface of the corner joint as the critical failure site. Moreover, creep strain was observed to accrue in a “step-wise” pattern, predominantly during the heating and cooling ramps, reflecting distinct temperature sensitivity. Utilizing the Syed model, the fatigue life was estimated at approximately 2239 cycles. These insights serve as a crucial benchmark for designing robust packages using Bi-doped, low-silver lead-free solders. Full article

The Esquel pallasite provides a valuable record of metal–silicate interaction in differentiated planetesimals, yet many aspects of its formation and thermal evolution remain uncertain. Here, we present a comprehensive multi-technique characterization of a single Esquel specimen, integrating SC-XRD, Raman spectroscopy, SEM–EDS, XPS, magnetic force microscopy, and X-ray computed tomography. Olivine grains are shown to be structurally pristine, with the first full crystallographic refinement for Esquel confirming a single-domain silicate lattice. XPS demonstrates a stoichiometric silicate surface containing only lattice O²⁻, Si⁴⁺, Mg²⁺, and Fe²⁺, indicating that olivine remained chemically unaltered. The Fe–Ni metal preserves diffusion-controlled taenite–kamacite exsolution, compositionally distinct plessite, accessory schreibersite and troilite as resolved by SEM. Quantitative Ni zoning, evaluated through interface-to-center gradients and a width–center-Ni correlation method, yields a self-consistent cooling rate of ~10–20 °C/Myr. MFM reveals microscale magnetic structures that correlate directly with Fe–Ni chemical zoning, providing magnetic confirmation of slow cooling. CT analysis further identifies interconnected metal networks, inclusions, and micro-porosity reflecting melt migration and late-stage modification. These results establish Esquel as an exceptionally well-preserved pallasite and demonstrate the value of integrated, multi-scale analytical workflows for reconstructing early Solar System processes. Full article

The blood-brain barrier (BBB) is one of the most selective physiological interfaces in the human body. Transendothelial electrical resistance (TEER) has become a widely adopted quantitative metric for assessing its in vitro structural and functional integrity. Although TEER measurements are routinely incorporated into BBB-on-chips, the absence of harmonized electrode architectures, measurement settings, and reporting standards continues to undermine reproducibility and translational reliability among laboratories. This systematic review provides the first comprehensive classification and critical comparison of electrode configurations used for TEER assessment, specifically within BBB-on-chip systems. Eligible studies were analyzed and categorized according to electrode design, fabrication method, integration strategy, and operational constraints. We critically evaluated six principal electrode architectures, highlighting their performance trade-offs in terms of uniformity of current distribution, long-term stability, scalability, and compatibility with dynamic shear conditions. Furthermore, we propose a bioinspired TEER reporting framework that consolidates essential metadata, including electrode specification, temperature control, viscosity effects, and blank resistance correction. Our analysis proposes screen-printed and hybrid silver-indium tin oxide (ITO) electrodes as promising candidates for next-generation BBB platforms. Moreover, our review provides a structured roadmap for standardizing TEER electrode design and reporting practices to facilitate interlaboratory consistency and accelerate the adoption of BBB-on-chip systems as truly biomimetic platforms for predictive neuropharmacological workflows. Full article

Climate-driven increases in wildfire activity threaten urban air quality both through long-range smoke transport from rural fires and direct exposure as the wildland–urban interface expands. Filters installed in Heating Ventilation and Air Conditioning (HVAC) systems represent a critical first barrier for limiting indoor exposure to smoke-derived particulate matter. In this study, we evaluated the smoke filtration performance of more than seventeen commercially available HVAC filter media spanning efficiency ratings from 10 to 15 (Minimum Efficiency Reporting Value, MERV) using pine needle combustion aerosols as a wildfire smoke proxy, quantifying size-resolved filtration efficiency, pressure drop, and temporal performance changes. The results show that charged polymer media across all tested MERV classes exhibited pronounced and rapid losses in smoke removal efficiency under exposure, despite minimal changes in airflow resistance. In contrast, mechanical media demonstrated greater stability in filtration efficiency over time but experienced considerable increases in pressure drop. Scanning electron microscopy revealed distinct smoke deposition morphologies on filter fibers, providing insight into mechanisms underlying performance degradation. Collectively, these findings indicate that filtration performance under wildfire smoke conditions is not adequately captured by current standards based on inorganic test aerosols. The results underscore the importance of advancing filter material evaluation and developing smoke-relevant testing approaches to better support indoor air quality, energy-aware building operation, and urban resilience under climate-driven wildfire smoke exposure. Full article

Perovskite quantum dots (PeQDs) are highly promising luminescent materials for next-generation displays owing to their excellent optoelectronic properties, such as narrow emission linewidth, high photoluminescence quantum yield, tunable bandgap, and solution processability. Blue-emitting PeQDs are particularly crucial for realizing full-color displays with high color purity. This review systematically summarizes synthesis strategies for blue-emitting PeQDs and their recent advances in perovskite light-emitting diodes (PeLEDs). We first introduce the working principles of PeLEDs and detail three primary approaches to achieving blue emission through mixed-halide engineering, quasi-two-dimensional structure construction via A-site cation substitution, and quantum size effect utilization. We then review mainstream synthesis methods, including hot-injection, ligand-assisted reprecipitation, and post-synthetic anion exchange, discussing their respective advantages and limitations. Key device optimization strategies are also outlined, covering surface passivation, core–shell structures, interface engineering, and light outcoupling enhancement. Finally, we address current challenges in material stability, efficiency roll-off, and charge imbalance and provide an overview of future research directions for high-performance blue PeLEDs based on PeQDs. Full article

Tick-borne pathogens (TBPs) are increasingly recorded in urban areas, where synanthropic wildlife may sustain pathogen transmission cycles. The European hedgehog (Erinaceus europaeus), frequently infested with ectoparasites, may serve as an urban reservoir of zoonotic TBPs. We investigated TBPs in host tissues and associated ectoparasites (Ixodes spp. and Archaeopsylla erinacei) from 129 hedgehogs in northwestern Italy. Anaplasma phagocytophilum, Borrelia burgdorferi sensu lato and Rickettsia spp. were detected in skin, spleen and ectoparasites (Ixodes spp. and Archaeopsylla erinacei). One spleen sample was positive for B. miyamotoi. Molecular identification revealed A. phagocytophilum ecotype 1, B. afzelii and B. bavariensis. A flea-borne Rickettsia closely related to the zoonotic Rickettsia asembonensis was identified for the first time in European hedgehogs. All pathogens were more prevalent in skin than in spleen. In skin, A. phagocytophilum and B. burgdorferi s.l. showed a positive interaction, whereas both were negatively associated with Rickettsia spp. These findings highlight hedgehogs as potential urban reservoirs of zoonotic TBPs, posing a potential risk for humans and domestic animals. The marked skin tropism of these pathogens supports the use of skin for TBP surveillance and underlines its role as a key interface for vector-borne transmission. Full article

This study aims to investigate the effects and underlying mechanisms of recycled sand replacement rate, additional water compensation factor, and recycled powder content on the strength, volumetric water absorption, and impermeability of recycled sand concrete. A total of 12 groups of concrete specimens with different mixtures were tested for their mechanical properties, volumetric water absorption, and chloride ion penetration. Furthermore, NMR and SEM analyses were conducted to reveal the microstructural mechanisms by which the additional water level and recycled sand content influence the mechanical performance and durability of the concrete. The results indicate that although recycled sand particles inherently contain numerous micro cracks, adhered porous cement paste, and pre-existing interfaces that enhance capillary water absorption and lead to reductions in strength and durability, these shortcomings can be mitigated by compensating for the additional water and controlling the recycled powder content. Increasing the additional water slightly reduces the strength of the recycled sand concrete. More importantly, appropriate amounts of additional water can reduce water absorption and improve the penetration resistance of recycled sand concrete. Furthermore, with an increase in recycled sand content, the strength, and impermeability of the concrete first increase and then decrease, reaching their maximum values at a recycled powder content of 4%. The water absorption of recycled sand concrete gradually increases with higher recycled powder content. Overall, recycled sand concrete can achieve satisfactory performance by optimizing the additional water amount and recycled powder content. It is recommended that the pre-saturation water compensation factor of recycled sand be maintained at 70%–80% of its 24 h saturated water absorption, and that the recycled powder content be controlled within 4%–8%. Full article

Effective drug delivery in oncology is challenged by a hierarchy of biological barriers—from abnormal vasculature and dense stroma to cellular immunosuppression and specialized interfaces like the blood–brain barrier. This review provides a contemporary analysis of smart nanoformulations through the lens of a rational, stage-gated design pipeline. We first deconstruct the solid tumor microenvironment as a multi-tiered obstacle (systemic, stromal, cellular), establishing a barrier-specific foundation for nanocarrier design. The core of the review articulates an architectural toolkit, detailing how intrinsic nanoparticle properties precondition in vivo identity via the protein corona, which in turn informs the selection of advanced ligands for cellular targeting and programmed intracellular trafficking. This integrated framework sets the stage for exploring sophisticated applications, including endogenous and externally triggered responsive systems, bio-orthogonal activation, immuno-nanoformulations, and combination strategies aimed at overcoming multidrug resistance. By synthesizing these components into a cohesive design philosophy, this review moves beyond a catalog of advances to offer a blueprint for engineering next-generation nanotherapeutics. We critically assess the translational landscape and contend that this hierarchical design approach is essential for developing more effective, personalized, and clinically viable cancer treatments. Full article

Service recommendation aims to assist users in selecting appropriate services according to their requirements while ensuring seamless compatibility in modern cloud and edge computing environments. In dynamic multi-cloud scenarios, services are typically deployed across heterogeneous cloud platforms and are frequently reconfigured. However, most existing service recommendation approaches primarily focus on static compatibility aspects, such as service interfaces or communication protocols, while overlooking the dynamic characteristics of service interactions. However, several limitations can be identified. First, the lack of effective mechanisms for quantifying service compatibility in dynamic cloud environments often leads to degraded system efficiency. Second, the absence of dedicated multi-cloud service compatibility quantification methodologies restricts recommendation accuracy. Third, insufficient mathematical analysis with respect to uniqueness, feasibility, and correctness may result in unstable evaluation outcomes and additional computational overhead. To overcome these limitations, this paper presents McCom, a multi-cloud service recommendation framework designed to quantify service compatibility performance and address the aforementioned challenges. First, a novel Markov chain-based compatibility quantification model is developed to characterize service interactions in dynamic multi-cloud environments. By exploiting the homogeneity, irreducibility, and convergence properties of Markov chains, the proposed model enables stable and reliable compatibility assessment. Second, a multi-cloud compatibility quantification strategy is introduced to mitigate interference arising from complex service pools through refined filtering and sketching mechanisms. Third, a series of mathematical proofs are provided to rigorously demonstrate the feasibility, correctness, and uniqueness of the proposed quantification method. Extensive simulation results indicate that the proposed framework achieves significant performance improvements, including enhancements in recommendation quality (14.44% in F1 score), reductions in latency (40.68%), and increases in accuracy (50.85%), compared with existing state-of-the-art approaches. Full article

Implant science has traditionally treated “biocompatibility” as the master criterion of success, focusing on cytotoxicity, corrosion, immune response, infection control, and the chemical stability of materials in vivo. However, many clinically “biocompatible” devices still fail at the point where the body actually meets the device: the mechanical interface. The interface is not a passive boundary. It is a living, adapting, mechanosensitive microenvironment in which cells integrate stiffness, micromotion, surface roughness, fluid shear, and wear debris with biochemical signals to decide whether to incorporate an implant, wall it off, resorb adjacent tissue, or trigger chronic inflammation. In load-bearing orthopaedics, stiffness mismatch produces stress shielding and maladaptive remodelling; excessive micromotion drives fibrous encapsulation rather than osseointegration; abrasive wear creates particulates that sustain macrophage activation and osteolysis; and design choices that are mechanically adequate in bench tests can still fail in vivo when the implant–tissue system evolves. In soft-tissue implantation, substrate stiffness can be a primary driver of the foreign body response and fibrotic capsule formation through mechanosensitive pathways, such as TRPV4-mediated macrophage–fibroblast signalling. Mechanical compatibility is not a replacement for classical biocompatibility; rather, it should be treated as a co-equal, first-class design requirement in mechanosensitive organisms. Chemically biocompatible materials can still fail through stiffness mismatch, micromotion, fretting and wear debris generation, and mechanobiology-driven fibrosis or osteolysis. We therefore propose a process view of implant success: tissue mechanics should be measured in clinically relevant states, transformed into constitutive models and interface performance envelopes, translated into explicit mechanical-compatibility specifications, and then realised through manufacturing process windows that can reliably reproduce targeted architectures and surface states. Additive manufacturing and microstructural engineering enable the tuning of modulus, the formation of porosity gradients, and the generation of patient-specific compliance fields, but these advances only improve outcomes when coupled to metrology, statistical process control, and validation loops that close the gap between intended and realised interface mechanics through clinical surveillance. Full article

As substantial incorporation of variable renewable generation technologies, particularly wind and photovoltaic systems, becomes more common, the complexities of power supply and demand characteristics are increasing, making it essential to conduct a detailed power and energy balance analysis. Aiming at regional power systems with multi-source structures and internal transmission interface constraints, this paper proposes a power and energy balance analysis method that considers demand-side carbon emissions. First, a closed-loop mechanism of “carbon signal–load response–balance optimization” based on nodal carbon potential (NCP) is constructed. In this framework, NCP is utilized to generate carbon signals that guide the active response of flexible loads, which are subsequently integrated into the coordinated optimization of power and energy balance. Second, a power and energy balance optimization model adapted to multi-source structures is established, where transmission power limits between zones are directly embedded into the constraint system, overcoming the defects of traditional heuristic methods that require repeated iterations to correct interfaces. Finally, an improved hybrid solution strategy for large-scale balance analysis is designed, significantly reducing the variable scale through the aggregation of similar units within zones. Case studies show that this method can effectively guide the load to shift toward low-carbon periods and nodes, significantly reducing total system carbon emissions and improving renewable energy consumption while ensuring power and energy balance. Full article

Land-use planning in Latin American coastal cities faces the challenge of integrating visions of the future with multiscale approaches amid high socio-environmental pressure. Using a mixed methodology that included documentary and comparative analysis of regulatory and planning instruments, workshops with experts, and evaluation matrices, this article analyzes the prospective and multiscale capabilities of the 2020–2032 Land Use Plan for the district of Santa Marta. This study provides a methodological and applied novelty by integrating, for the first time in this context, a dual analytical framework that simultaneously assesses the quality of the prospective dimension and the degree of multi-scalar articulation in coastal spatial planning. The study area is a strategic coastal territory exposed to environmental, urban, and socio-ecological pressures. The results reveal limitations in integrating future scenarios, polycentric governance, and adaptive coastal management, as well as a weak prospective approach limited to short time horizons, without constructed scenarios or early warning systems. At the same time, there is fragmented multiscale coordination between the local, regional, and national levels. These limitations partly explain the socio-environmental conflicts identified, particularly at the land-sea interface, where there is an apparent disconnect between urban planning and coastal management. On the other hand, significant progress has been made in the biophysical and social characterization of the territory. Our analysis generated specific knowledge for fast-growing intermediate cities, a critical type of coastal settlement, but less studied than large metropolises. The study provides a replicable framework for other seaside towns in the region. The study concludes that overcoming these gaps requires systematically incorporating forward-looking instruments and strengthening multilevel governance mechanisms. To this end, it summarizes lessons learned for more adaptive, resilient territorial planning in coastal contexts. Full article

This work aims to enhance the stability of the Mg/Al₃Y interface through first-principles investigations of low-cost dopants. Density functional theory calculations were employed to systematically examine the bulk properties of Mg and Al₃Y, as well as the structural stability, electronic characteristics, and alloying element effects at the Mg(0001)/Al₃Y(0001) interface. The calculated lattice parameters, elastic moduli, and phonon spectra demonstrate that both Mg and Al₃Y are dynamically stable. Owing to the similar hexagonal symmetry and a small lattice mismatch (~1.27%), a low-strain semi-coherent Mg(0001)/(2 × 2)Al₃Y(0001) interface can be constructed. Three representative interfacial stacking configurations (OT, MT, and HCP) were examined, among which the MT configuration exhibits significantly higher work of adhesion, indicating superior interfacial stability. Differential charge density and density of states analyses reveal pronounced charge transfer from Mg to Al/Y atoms and strong orbital hybridization, particularly involving Y-d states, which underpins the enhanced interfacial bonding. Furthermore, the segregation behavior and adhesion enhancement effects of typical alloying elements (Si, Ca, Ti, Mn, Cu, Zn, Zr, and Sn) were systematically evaluated. The results show that Mg-side interfacial sites, especially Mg₂ and Mg₃, are thermodynamically favored for segregation, with Zr and Ti exhibiting the strongest segregation tendency and the most significant improvement in interfacial adhesion. These findings provide fundamental insights into interfacial strengthening mechanisms and offer guidance for the alloy design of high-performance Mg-based composites. Full article

Transcutaneous electrical nerve stimulation techniques (TENS) are rapidly gaining attention for their potential in various clinical applications. One such technique is transcutaneous auricular vagus nerve stimulation (taVNS), and it involves delivering nerve stimulation through the skin of the external ear. However, taVNS relies on electrodes that must conform to the complex anatomy of the ear while maintaining stable electrical performance. Conventional taVNS electrodes, typically rigid metal or adhesive pads, are uncomfortable, difficult to position, prone to drying, and costly to produce. Here, we present and evaluate two complementary fabrication approaches for soft dry electrodes suitable for taVNS, which are compliant with curved anatomical features and can be operated without gel. The first employs wet spinning of a conductive elastomer into fibers, while the second extends this method to create hollow cylindrical geometries. The resulting spongy polymer composite electrodes exhibit tunable geometry, high conductivity, mechanical resilience under strain and compression, and low material impedance confirmed through bench and human testing, even under dry conditions. These properties are critical for in-ear and broader transcutaneous stimulation applications, highlighting the potential of these fabrication methods for next-generation soft bioelectronic interfaces. Full article