Search Results (641)

This investigation is to address the aerodynamic noise generated from laminar flow over a D-shaped cylinder at a low Reynolds number (Re). Proposed is a novel assembly of arc-shaped splitter plates to effectively reduce the aeolian tone for the D-shaped cylinder. The two-dimensional flow field is simulated at an Re of 160 to investigate the mechanism of reducing the sound of the arc-shaped plates. The radiated sound has been predicted by Ffowcs Williams and Hawkings (FW-H) acoustic analogy. To verify calculations, the predicted results of a circular cylinder have been compared with the data in the literature. The results reveal that the introduction of the arc plates decreases the lift and drag fluctuations as well as the vortex shedding frequency in comparison with the no-arc plate case. The pressure and velocity fluctuations in the wake zone are reduced by the arc plates due to vortex shedding suppression. The application of the arc plates shows an effective control of sound, leading to a maximum reduction in sound pressure level (SPL) by almost 34 dB. Full article

High-performance piezoelectric micromachined ultrasonic transducers (PMUTs) are crucial for portable medical imaging and sensing. The efficiency of advanced PMUTs relies on high-quality piezoelectric thin films and optimized device designs. However, variability in common piezoelectric thin films like Sc_xAl_1−xN (ScAlN) and PbZr_1−xTi_xO₃ (PZT) often leads to inaccurate material parameters—especially those derived from thick ceramics. To enhance simulation accuracy in standard designs affected by these inconsistencies, this work introduces an optimization framework combining first-principles calculations with multiphysics simulations. First, the intrinsic properties of PZT and ScAlN are analyzed through atomistic calculations, confirming that PZT, with its higher electromechanical coupling coefficient, is better suited for actuation. The parameters obtained from these calculations calibrate the finite-element model, addressing issues of missing or inaccurate data in commercial software libraries. Next, an efficient analytical acoustic-field model is developed. Compared to full-wave simulations in COMSOL, this model significantly reduces computational cost while maintaining accuracy, allowing for quicker scanning and optimization of large-array topologies. Additionally, results demonstrate that each individual hexagonal PMUT element outperforms a comparable circular element, achieving a peak SPL of 90.4 dB at 4.9 MHz versus 89.7 dB at 2.8 MHz. This higher acoustic output and operating frequency enable improved spatial resolution and sensitivity. This modeling approach, based on intrinsic material properties, provides a solid theoretical foundation for designing high-precision, low-power ultrasonic devices. Full article

This work presents a numerical–experimental validation of aeroacoustic predictions for bio-inspired leading edge serrated blade cascades. Transient simulations were carried out on a four-blade cascade using several turbulence modeling strategies commonly applied in broadband noise analysis—Spalart–Allmaras (SA), k−ω SST, k−ε, Scale-Adaptive Simulation (SAS), and Large Eddy Simulation (LES)—for assessing their capability to reproduce measured spectra. Multiple timestep resolutions were tested to ensure temporal accuracy. The comparison indicates that below 900 Hz, interaction noise is difficult to evaluate for such applications, whereas in the range from 0.9 to 5 kHz the turbulent jet–blade interaction is clearly captured. In the low-frequency regime (<1 kHz), the SA, SAS, and k−ω SST models exhibit similar behavior, while at higher frequencies SAS provides the closest agreement with experimental results, albeit with a slight tendency to overestimate at the upper end of the spectrum. LES demonstrates a satisfactory performance in reproducing the baseline response. The validation of numerical simulations with experimental results has been achieved, and a complex analysis using pressure measurements on the blade surface for a four-blade cascade configuration shows that turbulent formations lose their coherence quite significantly across several frequency bands. Overall, the results confirm that numerical simulations can reproduce the dominant experimental trends, while emphasizing the model-dependent trade-offs in predicting the acoustic benefits of bio-inspired leading edge serrations. Full article

The SQUAMOSA PROMOTER BINDING PROTEIN-LIKE (SPL) family, a group of plant-specific transcription factors, plays a key role in plant growth and development through complex regulatory networks. Within this family, SPL9 has been identified as a key regulator of diverse biological processes. In this review, we summarize the current knowledge on SPL9, focusing on its expression regulatory mechanisms and roles in plant development, such as morphogenesis, reproductive processes, and crop yield determinations. We further describe its role in plant responses to abiotic and biotic stresses and its integration into broader regulatory networks. We also outline future research priorities and discuss potential applications of SPL9-based strategies in molecular design breeding to increase crop productivity and stress resistance. Full article

This data descriptor presents a compact acoustic feature dataset derived from an open simulation-based study on electric vehicle gearbox housings with different structural stiffness levels. The dataset contains band-averaged sound pressure level (SPL) features extracted from radiated noise spectra of three housing concepts—flexible, intermediate, and rigid—differing only in ribbing configuration. Frequency-domain SPL spectra in the 1–6 kHz range were partitioned into five one-kilohertz bands, yielding a five-dimensional acoustic feature vector for each housing–microphone combination. In total, twelve feature vectors are provided, accompanied by stiffness labels and metadata describing the underlying simulation context. In addition to the dataset itself, baseline exploratory analyses are reported to illustrate potential reuse scenarios. Principal component analysis and unsupervised clustering demonstrate that mid-frequency bands, particularly between 2 and 4 kHz, exhibit sensitivity to housing stiffness, whereas total integrated spectral energy shows limited discriminative power. These analyses are intended to be illustrative examples rather than predictive models, given the deliberately small dataset size. The dataset is designed for reuse in benchmarking dimensionality reduction methods, clustering algorithms, uncertainty-aware classifications, and educational demonstrations of small-sample NVH data analysis. By providing a transparent and lightweight acoustic feature representation, this contribution supports reproducible research and early-stage comparative studies in drivetrain noise and vibration analysis. Full article

Flowering regulation in hemp is critical for determining fiber yield, seed production, and the accumulation of medicinal components. This paper, based on bibliometric analysis, highlights the current gap in basic research on cannabis floral organs. The latest advancements in flowering regulation are then systematically reviewed. The morphological and physiological foundations of flowering are examined, including the flowering phenotype, timing, and flower differentiation. Furthermore, the direct regulatory mechanisms of key environmental and cultivation factors—such as photoperiod (type, light quality, duration) and plant nutrition (fertilization, hormones)—on flowering are discussed. Potential pathways through which biotic and abiotic stresses indirectly affect flowering by disrupting metabolic processes are also explored. In addition, the genetic basis of flowering regulation, including key gene loci such as Autoflower1, Early1, and CsPRR37, as well as molecular networks like the FT-mediated photoperiod pathway and the miR156-SPL age pathway, is examined in detail. Finally, the industrial significance of flowering regulation is summarized, and future research directions are proposed to provide a theoretical foundation for the precise breeding and cultivation management of high-quality hemp varieties. Full article

The dominant sound sources in different urban spaces influence residents’ multidimensional emotional responses, and the interaction of various sound sources across temporal and spatial dimensions forms a complex sound environment. This study aims to develop a comprehensive index to quantify the emotional impacts of dominant sound sources. Through field measurements, this study classified the collected audios into four major categories (natural, social, construction, traffic) and 15 subcategories, with each sound source characterized by SPL and primary frequency. A total of 1266 questionnaires were collected from 209 participants through a web-based survey for the subjective experiment, while EEG data were obtained from 35 participants in the objective experiment. Next, by integrating acoustic indicators, subjective questionnaire responses, and objective EEG data, this study constructs the $C_K$ index using principal component analysis. $C_K$ provides a single, interpretable score of emotional impact, where lower values indicate greater calm. Results show that natural sounds consistently outperformed the other three sound types, showing the highest comfort (3.54) and pleasure (3.40) ratings on a five-point Likert scale, as well as the strongest physiological response with a parietal alpha power of 18.44 μV²/Hz. The calculated $C_K$ values for natural, social, construction, and traffic sounds were 8.73, 9.91, 10.20, and 10.29, respectively. This study contributes to quantifying the emotional impacts of urban sounds and refining noise mitigation priorities using the $C_K$ index. Full article

While bionic sawtooth and wave structures effectively reduce aerodynamic noise on fixed airfoils, their efficacy on rotating fans is often limited. Inspired by the protrusion structures of dragonfly wings and the gentle circular arches of manta rays, this study proposes a novel bionic circular arch structure to suppress aeroacoustic noise in axial flow fans. Numerical simulations were validated against experimental data from a standard fan, showing a sound pressure level (SPL) deviation within 3 dB at the first blade passing frequency (BPF), confirming calculation accuracy. The results indicate that the bionic design reduces the total SPL by approximately 2.5 dB. Notably, in the human-sensitive frequency range of 1000–3000 Hz, noise reduction reaches up to 6.6 dB at the upstream monitoring point. Analysis of Root Mean Square (RMS) fluctuating pressure and Fourier transforms reveals that the bionic structure significantly mitigates noise source intensity at the blade tip. This design effectively reduces pressure disturbances at the first BPF and shrinks the high-intensity disturbance region of the boundary layer compared to the prototype. Full article

This study investigated the individual and interactive effects of thermal and acoustic parameters on university students’ concentration and satisfaction in a library environment. Measurements of temperature, relative humidity (RH), and sound pressure level (SPL), alongside questionnaire surveys assessing students’ concentration, environmental perceptions, and satisfaction, were conducted over ten continuous working days in four library rooms. The results revealed significant interactive effects between operative temperature (To), RH, and background noise level (LA90) on students’ concentration and overall satisfaction, highlighting the importance of an integrated approach to managing Indoor Environmental Quality (IEQ). Furthermore, multi-objective optimization using the NSGA-II algorithm suggested optimal ranges for To (22.6–24.8 °C), RH (41.0–48.4%), and LA90 (45.0–48.5 dB(A)). Existing library conditions surpassed these optimal levels, particularly on the first floor, indicating a pressing need for interventions to enhance student well-being and academic performance. Overall, this study provides insights into the interactions between thermal comfort and acoustic quality, offering recommendations for creating more conducive learning environments that boost student satisfaction and performance. Full article

Conventionally designed piezoelectric micro-electro-mechanical systems (MEMS) speakers with thin-film-type, piston-type, and cantilever-type vibration membranes still adopt a Si supporting layer, which not only hinders the improvement of sound pressure level (SPL) but also lacks characterization of reliability. In this paper, we propose a fixed-end beam–cantilever piezoelectric MEMS speaker with a flexible supporting layer, achieving an SPL comparable to that of traditional three types of piezoelectric MEMS speakers with a Si supporting layer, and displaying good reliability. The measured results performed on encapsulated prototypes mounted to an acoustic test adaptor demonstrate that under a driving voltage of 1 V_rms, the SPL exceeds 51.6 dB in the human audible frequency range of 20 Hz–20 kHz, the total harmonic distortion (THD) remains below 3.4% above 430 Hz, satisfying the basic requirements for human auditory perception. Moreover, further experiments also prove its reliability by revealing no abnormal sound output, no fracture after being dropped from heights of 1 to 5 m, and the retention of over 92% SPL following 100 h of continuous music playback. This fixed-end beam–cantilever piezoelectric MEMS speakers with a flexible supporting layer provide researchers and enterprises with brand-new design ideas and a fresh perspective, which may potentially promote their development and practical application. Full article

Objectives: This study aimed to evaluate auditory cortical maturation in pediatric cochlear implant (CI) users using speech-evoked cortical auditory evoked potentials (CAEPs) and to compare P1 latency responses with age-matched normal-hearing (NH) peers. Secondary objectives included examining the relationship between P1 latency, age, and duration of implant use to assess experience-dependent cortical plasticity. Materials and Methods: Seventy children were enrolled, including 40 prelingually deaf CI users and 30 NH controls matched for age and sex. CAEPs were recorded using the HEARLab system with three speech tokens representing low (/m/), mid (/g/), and high (/t/) frequencies, presented at 55 dB SPL in a free-field setup. The P1 component was identified as the first positive deflection between 50 and 150 ms after stimulus onset. Group comparisons were performed using Student’s t-test, and correlations between P1 latency, age, and implant-use duration were analyzed using the Pearson correlation test (p < 0.05). Results: Mean P1 latencies were significantly longer in CI users than in NH peers for the /m/ and /t/ stimuli (p = 0.036 and p = 0.045, respectively), while no significant difference was found for /g/ (p = 0.542). In NH children, P1 latency negatively correlated with age (r = −0.44, p < 0.05), indicating maturation-related shortening. Among CI users, longer implant-use duration was associated with shorter P1 latencies across all speech tokens (/m/: r = −0.37; /g/: r = −0.49; /t/: r = −0.43; p < 0.05 for all). Conclusions: Speech-evoked CAEPs provide a sensitive and objective measure of auditory cortical development in children with cochlear implants. P1 latency reflects both chronological and hearing-age-related maturation, supporting its clinical use as a biomarker for cortical plasticity and rehabilitation progress in pediatric CI care. Full article

Underwater laser signal attenuation challenges conventional detection, while single-photon LiDAR (SPL) with high sensitivity shows promise. Existing underwater SPL studies primarily focus on isolated parameters, while the coupled effects of environmental and system parameters remain insufficiently investigated. In this work, a 532 nm underwater SPL system was developed to systematically explore multi-parameter coupling mechanisms in laboratory water tanks, including air and three turbidity levels, three detection distances, four laser energy levels, three integration times, and seven targets. This provides quantitative guidance for optimizing SPL systems in complex underwater environments. The results show that the SPL system maintained sub-nanosecond ranging precision, with the standard deviation (SD) of the ranging measurement at 50 cm being 0.0117 ns under low turbidity (0.11 m⁻¹) with 50% laser energy, while under high turbidity (4.2 m⁻¹) conditions, it increased to 0.0338 ns. At 100 cm, the SD was 0.0187 ns in low turbidity and rose to 0.0877 ns in high turbidity. Furthermore, the inversion error of the highly reflectivity minerals was kept within 3%, and the inversion value of reflectivity decreased exponentially with the increase of turbidity. Moreover, there is an important discovery for the phenomenon of the forward shift of photon flight time detected for highly reflectivity targets. Longer integration times effectively enhanced the signal-to-noise ratio (SNR) under severe attenuation, whereas excessive laser energy risked detector saturation. These findings provide a systematic characterization of how multifactor coupling governs SPL signal dynamics. The results validate the feasibility of SPL for complex underwater detection and offer theoretical insights and technical guidance for future marine applications in resource exploration, environmental monitoring, and national security. Full article

Accurate genotyping of small insertions and deletions (InDels; <5 bp) remains technically challenging in routine molecular breeding, largely due to the limited resolution of agarose gel electrophoresis and the labor-intensive nature of polyacrylamide-based assays. Here, we present the Tri-Primer Amplification Refractory Mutation System (TP-ARMS), a simple and cost-effective PCR-based strategy that enables high-resolution genotyping of small InDels using standard agarose gels. The TP-ARMS employs a universal reverse primer in combination with two allele-specific forward primers targeting insertion and deletion alleles, respectively. This design allows clear discrimination of homozygous and heterozygous genotypes using a two-tube PCR workflow. The method showed complete concordance with Sanger sequencing in detecting 1–5 bp InDels across multiple crop species, including rice (Oryza sativa) and quinoa (Chenopodium quinoa). In addition, using a TP-ARMS reduced experimental time by approximately 90% compared with PAGE-based approaches and avoided the high equipment and DNA quality requirements of fluorescence-based assays. The practical applicability of the TP-ARMS was demonstrated in breeding populations, including efficient genotyping of a 3-bp InDel in OsNRAMP5 associated with cadmium accumulation and a 6-bp promoter InDel in OsSPL10 underlying natural variation in rice trichome density across 370 accessions. Collectively, the TP-ARMS provides a robust, scalable, and low-cost solution for precise small InDel genotyping, with broad applicability in marker-assisted breeding and functional genetic studies. Full article

Bionic airfoils are an effective method to improve aerodynamic performance and reduce the noise of wind turbine blades. To explore the impact of the lower surface of bird wing airfoils on the aerodynamic performance and noise of blades, this study combines the upper surface of the NACA0018 airfoil with the lower surfaces of the teal, long-eared owl, and sparrowhawk (CBA-T, CBA-O, CBA-S) to create three new composite bionic airfoils (CBAs). The aerodynamic performance of these airfoils is evaluated, and the CBA-O airfoil is identified as having the best aerodynamic characteristics. A comparison of the noise and vortex structures of the CBA-O, owl wing airfoil, and NACA0018 is conducted, and the mechanisms behind the CBA-O airfoil performance improvement and noise reduction are explored. The results indicate that the CBAs enhance the aerodynamic performance of the airfoils. Before stall, the aerodynamic performance of the CBA-O improves the lift-to-drag ratio by 12.7% and 119.7% compared to the owl and NACA0018 airfoils, with its average SPL significantly lower than that of the NACA0018. The CBA-O has smaller vortex sizes at the trailing-edge, and the wake vortex develops more stably, effectively reducing both surface radiation noise and wake noise. Full article

Packaging is a fundamental component of food supply chains, enabling product protection, handling, and distribution from production to final consumption. In this context, the selection of secondary and tertiary packaging dimensions plays a critical role in improving logistics efficiency and reducing greenhouse gas (GHG) emissions associated with material use and transportation. This study proposes a sustainable packaging logistics (SPL) framework that systematically evaluates and optimizes packaging carton dimensions to enhance pallet utilization, transport efficiency, and packaging material efficiency. The framework is applied to a real-world case study from a meat processing company, demonstrating how alternative carton dimension configurations, while maintaining a constant product weight and functional equivalence, can significantly influence pallet-loading efficiency, transported payload, and associated CO₂-equivalent emissions. Rather than constituting a full life cycle assessment (LCA), the proposed approach adopts LCA-informed indicators to quantify material and transport related emission implications of packaging design choices. By integrating packaging design, palletization constraints, and logistics performance, the SPL framework provides a structured analytical basis for identifying packaging configurations that reduce material intensity and transport-related emissions. The results highlight the importance of packaging dimension optimization as a practical and scalable strategy for emission reduction in food supply chains. The proposed framework is intended to support decision-making in packaging design and to serve as a robust preparatory tool for future, more comprehensive LCA studies. Full article