Search Results (1,488)

This study focuses on a novel lightweight technology for manufacturing variable-axial fiber-reinforced polymer components. In the presented approach, channels following the load flow are implemented in an additively manufactured basic structure and impregnated continuous fiber bundles are pulled through these component-integrated cavities. Improved channel cross-section geometries to enhance the mechanical performance are proposed and evaluated. The hypothesis posits that increasing the surface area of the internal channels significantly reduces shear stresses between the polymer basic structure and the integrated continuous fiber composite. A series of experiments, including analytical, numerical, and microscopic analyses, were conducted to evaluate the mechanical properties of the composites formed, focusing on Young’s modulus and tensile strength. In addition, an important insight into the failure mechanism of the novel fiber composite is provided. The results demonstrate a clear correlation between the channel geometry and mechanical performance, indicating that optimized designs can effectively reduce shear stress, thus improving load-bearing capacities. The findings reveal that while fiber volume content influences the impregnation quality, an optimal balance must be achieved to enhance mechanical properties. This research contributes to the advancement of production technologies for lightweight components through additive manufacturing and the development of new types of composite materials applicable in various engineering fields. Full article

This study addresses the issue of cross-interference that occurs when locked continuous light and signal photons are collinear during interferometer measurements. To tackle this, a temperature-controlled Fabry–Pérot cavity filter with a heterogeneous cascaded structure is proposed and applied. The system consists of six filtering stages, created by designing Fabry–Pérot cavities of three different lengths, each used twice (to match optical frequencies), along with temperature control settings. By applying differentiated linewidth regulation, the approach effectively suppresses interference from locked light while significantly enhancing the signal-to-noise ratio in photon detection. This method overcomes the challenge of interference from same-frequency noise photons in atomic ensemble-entangled sources, achieving a noise–photon extinction ratio on the order of 10⁶ and surpassing the frequency resolution limit of a single filter. Experimental results demonstrate that the system reduces the noise floor in the detection optical path to below 10⁻¹⁶, while maintaining a photon transmission efficiency above 53% for the signal. This technology effectively addresses key challenges in noise suppression and photon state fidelity optimization in optical fiber quantum communication, offering a scalable frequency–photon noise filtering solution for long-distance quantum communication. Furthermore, its multi-parameter cooperative filtering mechanism holds broad potential applications in areas such as quantum storage and optical frequency combs. Full article

Bone immunity represents a dynamic interface where skeletal homeostasis intersects with systemic immune regulation. We synthesize emerging paradigms by contrasting two functionally distinct microenvironments: the marrow cavity, a hematopoietic and immune cell reservoir, and cancellous bone, a metabolically active hub orchestrating osteoimmune interactions. The marrow cavity not only generates innate and adaptive immune cells but also preserves long-term immune memory through stromal-derived chemokines and survival factors, while cancellous bone regulates bone remodeling via macrophage-osteoclast crosstalk and cytokine gradients. Breakthroughs in lymphatic vasculature identification challenge traditional views, revealing cortical and lymphatic networks in cancellous bone that mediate immune surveillance and pathological processes such as cancer metastasis. Central to bone immunity is the neuro–immune–endocrine axis, where sympathetic and parasympathetic signaling bidirectionally modulate osteoclastogenesis and macrophage polarization. Gut microbiota-derived metabolites, including short-chain fatty acids and polyamines, reshape bone immunity through epigenetic and receptor-mediated pathways, bridging systemic metabolism with local immune responses. In disease contexts, dysregulated immune dynamics drive osteoporosis via RANKL/IL-17 hyperactivity and promote leukemic evasion through microenvironmental immunosuppression. We further propose the “brain–gut–bone axis” as a systemic regulatory framework, wherein vagus nerve-mediated gut signaling enhances osteogenic pathways, while leptin and adipokine circuits link marrow adiposity to inflammatory bone loss. These insights redefine bone as a multidimensional immunometabolic organ, integrating neural, endocrine, and microbial inputs to maintain homeostasis. By elucidating the mechanisms of immune-driven bone pathologies, this work highlights therapeutic opportunities through biomaterial-mediated immunomodulation and microbiota-targeted interventions, paving the way for next-generation treatments in osteoimmune disorders. Full article

The floating oil seal (FOS) is a critical component in coal mining machinery, where frictional wear and high stress on the O-ring can lead to oil leakage and eventual FOS failure, significantly impairing equipment performance. To address this issue, this study proposes a novel ceramic-coated floating oil seal (NCCFOS) composite structure that enhances wear resistance without modifying the existing sealing cavity configuration. A two-dimensional axisymmetric finite element model of the NCCFOS was developed based on the Mooney–Rivlin constitutive model, considering the O-ring assembly process for improved accuracy. The model was analyzed under oil pressure loading, with parametric studies examining the influence of oil pressure, assembly clearance, and material hardness on O-ring stress, contact pressure, and frictional stress distribution in the floating seal ring. The results demonstrate that accounting for the assembly process yielded more realistic stress predictions compared to conventional modeling approaches. The NCCFOS design effectively mitigated stress concentrations, reduced O-ring wear, and extended fatigue life, offering a practical solution for enhancing the reliability of coal mining machinery seals. Full article

In offshore drilling and geological exploration, the stability of jack-up rigs is predominantly determined by the bearing capacities of spudcan foundations during seabed penetration. The penetration depth of spudcans is relatively shallow in hard clay. The formation of a cavity on the top surface of a spudcan often complicates accurate estimation of its capacity. This study employs the finite element method, in conjunction with the Swipe and Probe loading techniques, to examine the failure surfaces of soils of varying strengths. Numerical simulations that consider different gradients of undrained shear strength and cavity depths demonstrate that cavity depth significantly influences the failure envelope. The findings indicate that higher soil strength increases the bearing capacity and reduces the area of soil displacement at failure. Moreover, an enhanced theoretical equation for predicting the vertical-horizontal-moment (V-H-M) failure envelope in hard clay strata is proposed. The equation’s accuracy has been verified against numerical simulation results, revealing an error margin of 3–10% under high vertical loads. This model serves as a practical and valuable tool for assessing the stability of jack-up rigs in hard clay, providing critical insights for engineering design safety and risk assessment. Full article

Environmental noise is a growing public health issue, particularly in dense urban environments and areas adjacent to transport infrastructure. Passive acoustic barriers have been a widely adopted solution, although their functional and aesthetic limitations have driven the development of alternatives, such as Sonic Crystal Acoustic Barriers. These structures can incorporate resonant elements, such as Helmholtz cavities, with the aim of enhancing attenuation in particular frequency bands. However, determining the precise dimensions of these resonators is a persistent challenge, given that classical models are based on ideal geometries and do not incorporate interaction with the periodic structural environment. This study sets a new frequency-dependent correction factor, obtained both numerically and experimentally, which allows the classical Helmholtz resonance expression to be adjusted to the case of resonators embedded in a Sonic Crystal (SC). The proposed model is validated through simulations and experimental measurements, showing a significant improvement in the prediction of the resonance frequency. The results obtained in this study allow us to move towards a more efficient and realistic design of passive acoustic barriers that are lightweight and adaptable to the urban environment. Full article

This work studies the Purcell effect of two quasiperiodic multilayers of gold and titanium dioxide following the Thue–Morse and Fibonacci sequence, respectively. We systematically investigated the impacts of polarization direction, dipole height, and wavelength on the Purcell factor. Additionally, we compared the normalized field distribution profiles across all multilayer structures. Concurrently, under varying polarizations, we computed the radiative part of the Purcell factor, photoluminescence at the reflection and transmission side of multilayers, respectively. Our findings indicate that under near-field excitation conditions, the Purcell factor is predominantly governed by its non-radiative component rather than the radiative one. We attribute the observed discrepancies in the Purcell factor to variations in the intensity and spatial distribution of non-radiative losses within the metallic components of the multilayers. This mechanism provides a robust physical foundation for exploring and extending the applications of photonic quasicrystals in the modulation of nanoscale light–matter interactions. Furthermore, we examined cavities constructed from symmetric multilayers. Under z-polarization and long-wavelength conditions, the cavity effect was observed to enhance the radiative part of the Purcell factor, thereby further boosting spontaneous emission efficiency. This work offers novel insights into the design of semiconductor devices with improved quantum emission efficiency and photoluminescence. Full article

Effective thermal management of molds is a governing factor of the quality and stability of the injection molding process. This study introduces and validates an integrated cooling layer within a thin-walled insert mold designed to enhance thermal control and cavity filling performance. A coupled heat transfer simulation model was developed and subsequently calibrated against experimental temperature measurements. To isolate the mold’s intrinsic thermal response, temperatures were measured during distinct heating and cooling cycles, free from the perturbations of polymer melt flow. The validated mold was then installed on a Haitian MA1200 III injection molding machine to conduct molding trials under various injection pressures. A strong correlation was found between the simulation and experimental results, particularly as pressure increased, which significantly improved cavity filling and reduced the deviation between the two methods. The integrated cooling layer was shown to enhance heat dissipation, minimize thermal gradients, and promote a more uniform thermal field. This, in turn, improved filling stability, especially at moderate injection pressures. These findings provide robust quantitative data for simulation model calibration and mold design optimization, highlighting the potential of advanced cooling strategies to significantly enhance injection molding performance. Full article

This study presents a comparative evaluation of post-process sensor integration in additively manufactured (AM) metal and the in-situ process for polymer structures for structural health monitoring (SHM), with an emphasis on embedded sensors. Geometrically identical specimens were fabricated using copper via metal fused filament fabrication (FFF) and PLA via polymer FFF, with piezoelectric transducers (PZTs) inserted into internal cavities to assess the influence of material and placement on sensing fidelity. Mechanical testing under compressive and point loads generated signals that were transformed into time–frequency spectrograms using a Short-Time Fourier Transform (STFT) framework. An engineered RGB representation was developed, combining global amplitude scaling with an amplitude-envelope encoding to enhance contrast and highlight subtle wave features. These spectrograms served as inputs to convolutional neural networks (CNNs) for classification of load conditions and detection of damage-related features. Results showed reliable recognition in both copper and PLA specimens, with CNN classification accuracies exceeding 95%. Embedded PZTs were especially effective in PLA, where signal damping and environmental sensitivity often hinder surface-mounted sensors. This work demonstrates the advantages of embedded sensing in AM structures, particularly when paired with spectrogram-based feature engineering and CNN modeling, advancing real-time SHM for aerospace, energy, and defense applications. Full article

Diabetes has become a global health challenge, driving the demand for innovative, non-invasive diagnostic technologies to improve glucose monitoring. Urinary glucose concentration, a reliable indicator of metabolic changes, provides a practical alternative for frequent monitoring without the discomfort of invasive methods. In this simulation-based study, we propose a novel asymmetric photonic structure that integrates Tamm plasmon polariton (TPP) modes and a cavity mode for high-precision refractive index sensing, with a conceptual focus on the potential detection of urinary glucose. The structure supports three distinct resonance modes, each with unique field localization. Both the TPP modes, confined at the metallic–dielectric interfaces, serve as stable references whose wavelengths are unaffected by refractive-index variations in human urine, whereas the cavity mode exhibits a redshift with increasing refractive index, enabling high responsiveness to analyte changes. The evaluation of sensing performance employs a sensitivity formulation that leverages either TPP mode as a reference and the cavity mode as a probe, thereby achieving dependable measurement and spectral stability. The optimized design achieves a sensitivity of 693 nm·RIU⁻¹ and a maximum figure of merit of 935 RIU⁻¹, indicating high detection resolution and spectral sharpness. The device allows both reflectance and transmittance measurements to ensure enhanced versatility. Moreover, the coupling between TPP and cavity modes demonstrates hybrid resonance, empowering applications such as polarization-sensitive or angle-dependent filtering. The figure of merit is analyzed further, considering resonance wavelength shifts and spectral sharpness, thus manifesting the structure’s robustness. Although this study does not provide experimental data such as calibration curves, recovery rates, or specificity validation, the proposed structure offers a promising conceptual framework for refractive index-based biosensing in human urine. The findings position the structure as a versatile platform for advanced photonic systems, offering precision, tunability, and multifunctionality beyond the demonstrated optical sensing capabilities. Full article

Background/Objectives: Maxillofacial volumetric deficits are often treated using structural fat grafting with autologous free fat grafts. The buccal fat pad (BFP) is commonly used as a pedicled flap for limited oral cavity applications. This study explores its use as a free graft for reconstructing deformities in the upper and lower lips caused by trauma or tumor resections. Methods: Five patients underwent soft tissue defect reconstruction using a free fat graft from the BFP, following standard surgical procedures. Techniques for harvesting, transferring, and evaluating aesthetic and functional outcomes up to three months post-surgery are detailed, with long-term follow-up extending to an average of 20 months (range 12–24 months). Results: Initial post-operative assessments showed lip asymmetry due to edema and excessive graft volume. Partial necrosis was observed within 1–2 weeks, typical of tissue healing. By 4–5 weeks, mucosal revascularization occurred, with desired lip volume and functionality achieved between 8–12 weeks. Long-term follow-up averaging 20 months demonstrated excellent graft stability with no volume regression beyond the vermilion border in all patients. Conclusions: The BFP as a free graft offers advantages such as high survival rates and easy harvesting. It effectively restores lip function, volume, and aesthetics. Challenges include graft manipulation, retention, potential fibrosis, and volume unpredictability. Future refinements in technique and follow-up are necessary to overcome these issues, enhancing the reliability of BFP for lip reconstruction. Full article

This study analyzes the spectral properties of word-initial and intervocalic ejectives in Wolaytta, an Omotic language of southern Ethiopia. Using tokens embedded in three vowel contexts, we examined mean burst intensity, spectral moments, and vowel perturbation following ejection. Results show that ejectives adjacent to high front vowels were produced with greater intensity, supporting the hypothesis that increased oral cavity tenseness correlates with acoustic energy. Centroid and standard deviation differentiate place of articulation, while skewness and kurtosis distinguish singleton from geminate ejectives. Post-ejective vowel pitch and spectral tilt varied systematically with the ejectives’ place of articulation, indicating creaky phonation induced by ejection. Overall, the findings enhance our understanding of factors impacting acoustic features of ejectives. Full article

In laser wireless power transmission systems, the powersphere serves as a spherical enclosed receiver that performs photoelectric conversion, achieving uniform light distribution within the cavity through infinite internal light reflection. However, in practical applications, the high level of light absorption displayed by photovoltaic cells leads to significant disparities in light intensity between directly irradiated regions and reflected regions on the inner surface of the powersphere, resulting in poor light uniformity. One approach aimed at addressing this issue uses a spectroscope to split the incident beam into multiple paths, allowing the direct illumination of all inner surfaces of the powersphere and reducing the light intensity difference between direct and reflected regions. However, experimental results indicate that light transmission through lenses introduces power losses, leading to improved uniformity but reduced output power. To address this limitation, this study proposes a method that utilizes multiple incident laser beams combined with a centrally positioned spherical reflector within the powersphere. A wireless power transmission system model was developed using optical simulation software, and the uniformity of the intracavity light field in the system was analyzed through simulation. To validate the design and simulation accuracy, an experimental system incorporating semiconductor lasers, spherical mirrors, and a powersphere was constructed. The data from the experiments aligned with the simulation results, jointly confirming that integrating a spherical reflector and distributed incident lasers enhances the uniformity of the internal light field within the powersphere and improves the system’s efficiency. Full article

We report high-resolution, cavity-enhanced direct frequency comb Fourier transform spectroscopy of cold acetylene (C₂H₂) molecules in a planar supersonic jet expansion. The experiment is based on a near-infrared frequency comb with a 300 MHz effective repetition rate, matched to a high-finesse enhancement cavity traversing the jet. The rotational and translational cooling of acetylene was achieved via expansion in argon carrier gas through a slit nozzle. By interleaving successive mode-resolved spectra measured at different comb repetition rates, we retrieved full absorption line profiles. Spectroscopic analysis reveals sharp, Doppler-limited transitions corresponding to a jet core rotational temperature below 7 K. Frequency comb and cavity stabilization were achieved through active Pound–Drever–Hall locking and mechanical vibration damping, enabling a spectral precision better than 2 MHz, limited by the vibrations induced by the pumping system. The demonstrated sensitivity reaches a minimum detectable absorption of 7.8 × 10⁻⁷ cm⁻¹ over an 18 m effective path length in the jet core. This work illustrates the potential of cavity-enhanced direct frequency comb spectroscopy for precise spectroscopic characterization of cold supersonic expansions, with implications for studies in molecular dynamics, reaction kinetics, and laboratory astrophysics. Full article

Mesenchymal stem cells (MSCs) spontaneously assemble into three-dimensional (3D) spheroids under matrix-deficient conditions such as the synovial cavity, although their functional significance has yet to be fully elucidated. In this study, we used concave microwell cultures to promote the spontaneous aggregation of adipose-derived MSCs (ASCs) from OA patients, thereby mimicking the intra-articular microenvironment. We analyzed the paracrine factors of ASC aggregates and compared it with that of conventional 2D monolayer cultures. Notably, 3D aggregation significantly increased the secretion of HGF and VEGF, whereas FGF2 levels remained relatively unchanged. These results indicate that the structural characteristics of ASC aggregates enhance the secretion of key paracrine factors involved in angiogenesis and tissue repair. To functionally evaluate the biological relevance of the secreted factors, conditioned media (CM) from ASC aggregates were applied to human articular chondrocytes. The CM significantly promoted chondrocyte proliferation, an effect that was abolished by the addition of HGF-neutralizing antibodies, thereby highlighting HGF as a central mediator of the regenerative response. Additionally, we further explored whether extracellular factors could modulate growth factor expression such as HGF. In this context, we investigated the impact of low-concentration hyaluronic acid (HA), a key synovial component widely used in OA treatment. Co-treatment with HA not only amplified the expression and secretion of HGF, VEGF, and FGF2, but also promoted ASC proliferation. ASCs forming functional aggregates may exert regenerative effects as active paracrine modulators, and the addition of low-dose hyaluronic acid is expected to further enhance this function, offering a promising strategy for MSC-based osteoarthritis therapy. Full article