Search Results (179)

Background/Objectives: Patient-derived mesenchymal stem cells (MSCs) represent a promising avenue for myocardial regeneration, yet therapeutic application remains limited by inconsistent differentiation capacity and the absence of standardized cardiogenic induction protocols. This study demonstrates a proof-of-concept for guiding patient-specific bone marrow MSCs toward a functional cardiomyocyte phenotype using paracrine signals from differentiating iPSC-derived cardiomyocytes (iPSC-CMs). Materials and Methods: MSCs were maintained in conditioned medium from a concurrent, validated iPSC-CM differentiation protocol, with evaluation via immunocytochemistry, optical mapping, and whole-cell patch-clamp recordings. Results: Differentiated MSCs acquired organized sarcomeric architecture with cross-striations and displayed spontaneous calcium oscillations with decay kinetics matching source iPSC-CMs (CaT50 ≈ 283 ms vs. 301 ms). In co-culture, MSC-derived cells exhibited synchronized calcium dynamics with iPSC-CMs, confirming functional coupling, while patch-clamp detected hallmark cardiac ion currents (INa, ICa,L, and IKv). Morphologically, MSC-CMs displayed more mature, elongated rod-like shapes. Conclusions: Although current densities indicate partial immaturity, their reproducible detection validates successful cardiomyogenic commitment. This “parallel differentiation” platform eliminates donor-specific protocol tuning, providing a streamlined, paracrine-mediated approach to generate autologous cardiomyocyte-like cells for disease modeling, pharmacological testing, and future regenerative applications. Full article

Voltage sags pose severe risks to sensitive equipment in modern industries, requiring power quality monitoring equipment to possess fast and accurate sag detection capabilities. The traditional second-order generalized integrator (SOGI) will have oscillation phenomena in the case of DC offset, low-frequency harmonics, and high-frequency impulse noise. This study introduces a strong detection algorithm that combines Adaptive Composite Morphological Filtering (ACMF) with an improved Mixed Second- and Third-Order Generalized Integrator (MSTOGI). First, the ACMF pre-filtering module dynamically adjusts the scale of composite structuring elements through periodic parameter optimization, effectively filtering high-frequency random impulses while preserving the sharp transitions of abrupt voltage changes. Second, MSTOGI eliminates DC offset, and optimizes the gain coefficient to achieve the best dynamic response speed. Ultimately, a cascaded notch filter (CNF) module focuses on and removes even-order harmonic ripples caused by the synchronous reference frame transformation. Simulation results indicate that under severe grid conditions involving multiple composite distortions, the proposed architecture reduces the sag detection time to within 1.0 ms under typical operating conditions, with steady-state phase errors strictly controlled within a ±2° range. This method provides a reliable solution for DVR and UPS. Full article

Inspired by the wing-opening morphology of dragonflies, a series of bio-inspired dragonfly-shaped bluff bodies are designed and investigated, and further integrated into a piezoelectric wind energy harvester. The energy-harvesting performance and aerodynamic responses of bluff-body configurations with different wing-opening angles (0°, 15°, 30°, 45°, and 60°) are comparatively analyzed through a combination of numerical simulations and wind tunnel experiments. Experimental results demonstrate pronounced differences among the configurations in the low wind speed regime. Specifically, the prototype with α = 0° achieves relatively higher output under very low wind speeds, whereas the α = 15° configuration exhibits the best overall performance across the entire tested wind speed range. Taking the α = 15° case as an example, the cut-in wind speed is reduced to 1.7 m/s, while the maximum RMS voltage and output power are increased by 20.16% and 44.39% compared with the cuboid bluff body, and by 50.95% and 127.84% compared with the cylinder bluff body, respectively. Further CFD results reveal that, at specific wing-opening angles, the dragonfly-shaped bluff body undergoes a coupled vortex-induced vibration (VIV) and galloping response, enabling certain configurations to sustain stable oscillations with large amplitudes over a relatively wide wind speed range. Within the investigated parameter range, an appropriate selection of the wing-opening angle effectively balances the cut-in capability and output stability under low wind speed conditions. These findings provide useful design guidelines for flow-induced vibration-based wind energy harvesters operating in low wind speed environments. Full article

This study presents a two-stage, mechanics-based method for optimizing vibratory sorting machine of adult crickets for post-harvest size grading. In the first stage, the static coefficient of friction (COF) was measured for three cricket size classes across seven tray surface conditions to quantify cricket–substrate interactions relevant to vibratory transport. COF varied significantly with both morphology and surface microtexture (p < 0.0001), with intermediate roughness levels generating higher friction than smooth or highly rough surfaces. In the second stage, a factorial experiment evaluated the effects of oscillating speed (300–350 rpm), tray inclination (2°–3°), and surface roughness (G0–G5) on sorting efficiency, throughput, batch sorting time, and specific energy consumption (SEC). All main factors and most interactions significantly influenced sorting performance (p < 0.0001). The optimal operating condition—350 rpm, 2° inclination, and G2 roughness—achieved 95% sorting accuracy, 39 crickets·min⁻¹ throughput, and the lowest SEC (0.37 Wh·cricket⁻¹). The results demonstrate that friction–vibration coupling governs cricket transport on vibrating surfaces and provide an engineering framework for designing scalable, energy-efficient sorting systems for insect rearing and processing. Full article

This study utilized oscillating laser cladding technology to fabricate nickel-based composite coatings, systematically investigating the influence of varying laser powers on their morphology, microstructure, and properties. The results indicate that as laser power increases from 800 W to 1400 W, the dilution rate of the coating exhibits a non-monotonic change, reaching a maximum at an intermediate laser power due to the competing effects of enhanced substrate melting and melt-pool instability. The microstructure of the coatings is primarily composed of dendritic and equiaxed crystals. Elemental analysis revealed that Ni is predominantly enriched within the dendritic regions, whereas Cr segregates toward the grain boundary areas. Furthermore, the microhardness of the coating, as well as its anti-wear and anti-corrosion properties, are positively correlated with the laser power. When the power reaches the maximum value of 1400 W studied, the performance of the coating significantly improves. The average hardness is 482 HV, and the relative wear resistance is approximately 1.8 times that of the coating when the power is 800 W. The corrosion current density is 9.04 × 10⁻⁷ A/cm². Full article

Despite decades of studies on symmetric impinging-jet atomization, the combined role of controlled pre-impingement asymmetry and viscosity in setting the instability pathways and droplet statistics of laminar microjets remains insufficiently quantified. The effects of pre-impingement jet-length difference and liquid viscosity on the flow morphologies, instability dynamics, and atomization behavior of laminar impinging microjets are investigated experimentally using high-speed imaging. By systematically varying the jet-length asymmetry and viscosity over a range of Weber numbers, the evolution of liquid-sheet motion and breakup is resolved from synchronized front- and side-view observations. Specifically, the scientific objective of this work is to elucidate how pre-impingement jet-length asymmetry and liquid viscosity jointly regulate the dynamical behavior of laminar impinging microjets, with particular emphasis on regime transitions of liquid-sheet morphologies, the coupling between upper-sheet oscillations and rim instabilities revealed by synchronized multi-view imaging and POD-based frequency analysis and the resulting droplet-size statistics. These aspects address physical questions that have not been systematically resolved in classical impinging-jet studies, which predominantly focus on symmetric configurations or performance-oriented atomization. With increasing Weber number, the flow undergoes a sequence of regime transitions, including merged-jet, liquid-chain, wavy-rim, fishbone, closed-rim, open-rim, and arc-shaped atomization states. The presence and extent of the closed-rim regime depend sensitively on both jet-length asymmetry and liquid viscosity. Increasing jet-length difference accelerates transitions between these regimes, whereas increasing liquid viscosity stabilizes the liquid sheet and shifts the onset of unsteady breakup to higher Weber numbers. Proper orthogonal decomposition is applied to time-resolved image sequences to extract dominant oscillatory modes and their characteristic frequencies. Within the fishbone regime, the oscillation frequency of rim deformation either coincides with that of the upper region of the liquid sheet or appears as its subharmonic, indicating period-doubling behavior under specific combinations of Weber number and jet-length asymmetry. These frequency characteristics govern the spatiotemporal organization of ligament formation and detachment along the sheet rim. In the arc-shaped atomization regime, droplet-size distributions follow a log-normal form, and at sufficiently high Weber numbers, the mean droplet diameter shows only a weak dependence on jet-length asymmetry. These findings provide microscale-regime guidance for tunable droplet formation in open microfluidic jetting and related small-scale multiphase flows. The innovation of this study lies in the systematic use of synchronized multi-view imaging combined with POD-based frequency analysis and droplet statistics to directly connect liquid-sheet oscillations, rim instability dynamics, and breakup organization under controlled geometric asymmetry and viscosity variations. This approach enables a unified physical interpretation of regime transitions and instability mechanisms that cannot be resolved from single-view observations or morphology-based classification alone. Full article

This study examines the joining characteristics of Cu foil stacks to lead tabs using green-laser welding in the main-welding step of a sequential welding process for lithium-ion pouch cells. The influence of lap configuration, line and wobble seam strategies, and process parameters was systematically investigated in terms of bead morphology, mechanical performance, metallurgical characteristics, and electrical resistance. Under the present line-welding parameter window (2.0 kW, 100–200 mm/s), humping, pinholes, and porosity were observed, particularly in the upper lead-tab configuration, which is attributed to melt-pool/keyhole instability under the applied conditions. Wobble welding effectively suppressed these defects in the foil-stack configuration by promoting stable melt flow and efficient bubble expulsion. Mechanical tests revealed that the wobble-based seam strategy achieved a maximum tensile–shear load of approximately 1.28 kN at a wobble amplitude of 0.8 mm. Fracture analysis confirmed a transition from seam-type interfacial failure in line welding to ductile tearing in the heat-affected zone with wobble welding. In electrical performance, wobble welding reduced resistance to as low as 45 µΩ at a wobble amplitude of 1.2 mm, while line welding yielded higher and scattered values. These results should be interpreted as the combined outcome of the wobble-based seam strategy (beam oscillation together with overlapped stitch welding at a lower travel speed) under the present processing windows. A strictly matched A/B comparison at identical linear energy density and seam layout will be investigated in future work to isolate the effect of oscillation. Full article

Ammonia (NH₃) is a promising carbon-free energy carrier for low-carbon power generation. However, in turbulent ammonia–methane (NH₃-CH₄) premixed swirling flames, operating at lean conditions to limit NO_X, emissions can trigger strong thermoacoustic oscillations. This study investigates thermoacoustic oscillatory instability in an NH₃-CH₄ swirl-stabilized combustor using the chemiluminescence of CH*, OH*, and NH* over a wide range of ammonia fuel fraction (X_NH3). Combined spectral measurements and 2D chemiluminescence imaging are employed to obtain the global emission characteristics and spatial distributions of OH* and NH* in the UV band and CH* in the visible band. A custom-designed intensified CMOS (ICMOS) camera based on a high-gain UV–visible image intensifier with direct coupling is developed to enable sensitive OH* and NH* imaging (gain > 10⁴). Frequency analysis of continuous CH* imaging, together with morphology-based principal component analysis and k-means clustering of 46 image features, shows that oscillatory combustion occurs for X_NH3 < 0.40, whereas X_NH3 ≥ 0.40 leads to multimode, stable combustion. As X_NH3 increases, OH* and NH* fields progressively decouple from CH*, becoming more elongated and shifting downstream. These results demonstrate that UV radical chemiluminescence provides indispensable information on NH₃ reaction zones and should be combined with CH* diagnostics for reliable thermoacoustic analysis and control in practical NH₃-fueled combustion systems. Full article

Kaolin is an abundant, low-cost filler for elastomeric compounds. The kaolin used here is primarily kaolinite, chemically clean, and contains a fine particle population. Although agglomeration is evident, it can be mitigated by appropriate physical processing and, when desired, by chemical coupling. This study evaluates kaolin in natural rubber (NR) and examines how adding bis(triethoxysilylpropyl) tetrasulfide (TESPT) during mixing affects filler–matrix compatibility, viscoelastic response, cure stability, and mechanical performance. Kaolin was structurally and morphologically characterized, and the compounds were prepared in a closed mixer coupled to a torque rheometer under controlled dispersion conditions. Part 1 assessed NR with kaolin without a coupling agent, and Part 2 assessed the NR–kaolin with TESPT added during mixing (0.5 and 5 phr). Small-amplitude oscillatory shear (SAOS) was used to probe viscoelastic behavior, while oscillating disk rheometry (ODR) and tensile tests quantified cure and mechanical properties. In Part 1, kaolin increased NR stiffness in SAOS and raised the 100% and 300% moduli by about 40% and 50%, respectively, relative to the unfilled NR compound, while reducing cure reversion from 30% to 10% at 150 °C. In Part 2, TESPT produced a threshold-like response: 0.5 phr caused only minor changes, whereas 5 phr led to pronounced stiffening and cure stabilization. At 5 phr, a low-frequency plateau in G′ below 0.1 Hz with no G′–G″ crossover was observed, accompanied by higher M_H and ΔM in ODR and reversion suppressed to 1% after 30 min. These trends indicate the formation of a more connected filler-rubber network, promoted by TESPT-assisted interfacial coupling/adhesion, while also reflecting the ability of TESPT (tetrasulfide) to contribute sulfur and modify the curing chemistry. Mechanically, kaolin produced marked stiffness increases, with the 100% and 300% moduli increasing by an additional 9% and 36%, respectively, at 5 phr TESPT. At the same time, ultimate tensile strength remained lower than that of neat NR, and elongation at break decreased slightly. Overall, adding TESPT during mixing enhances interfacial coupling and network connectivity and, at higher loading, also influences cure chemistry, yielding higher modulus and strongly improved reversion resistance without increasing ultimate tensile strength relative to neat NR. Full article

Reliable joining of multi-layer aluminum foil current collectors is crucial for enhancing the performance and safety of high-capacity lithium-ion batteries. However, laser welding of such thin-thick aluminum combinations is often hindered by porosity, cracks and unstable weld-pool behavior. In this study, a ring-mode fiber laser combined with sinusoidal oscillation and linearly gradient power modulation was employed to achieve high-quality lap welding between 80 layers of 1060 aluminum foil (1 mm in total thickness) and a 1.5 mm thick aluminum plate. Welding experiments and thermo-mechanical simulations were conducted to investigate the effects of welding speed (15–45 mm/s) and central-power modulation parameters (−2, 0, +2, +4) on weld morphology, defect formation, and mechanical properties. The results indicate that increasing the welding speed can effectively suppress cracks and improve the shear strength from 249.8 N to 403.9 N, but it also leads to an increase in porosity from 5.78% to 12.26% and deterioration of the weld reinforcement. Higher central-power modulation (+2, +4) transformed the weld-pool geometry from an ω shape to U shape, effectively suppressing fusion-line cracks but leading to increased porosity (up to 8.41%) and deteriorated surface morphology. Overall, a low welding speed of 15 mm/s combined with an optimized power modulation strategy achieves effective crack suppression while maintaining controlled porosity, resulting in a welded joint with superior comprehensive performance. This research provides a robust process solution for high-quality laser welding of multi-layer aluminum foil current collectors in power battery manufacturing. Full article

Single-lane tunnels, characterized by narrow and high cross-sections with limited ventilation, present significantly higher fire hazards than conventional multi-lane tunnels. To investigate flame morphology and ceiling temperature evolution in such confined spaces, a comprehensive set of reduced-scale fire tests was conducted using a 1:10 scale tunnel model based on Froude similarity. The effects of the heat release rate (HRR), transverse fire location, and fire source height were systematically analyzed. The results indicate that the transverse fire location critically influences flame behavior: a centerline fire produces a stable, vertically symmetric flame, whereas a wall-attached fire exhibits a periodic oscillation of attachment, elongation, and detachment. The maximum ceiling temperature rise increases with both HRR and fire source height. Notably, compared to a centerline fire, a wall-attached fire can increase the maximum ceiling temperature rise by up to 39% due to sidewall confinement. Based on the experimental data, a predictive correlation for the maximum ceiling temperature rise under centerline fire conditions was established. Furthermore, a global prediction model incorporating a transverse position coefficient was proposed, which shows good agreement with the experimental results. Comparative analysis reveals that the temperature rise coefficient for the single-lane tunnel is approximately 13% higher than that of multi-lane tunnels. These findings provide a theoretical basis for fire risk assessment and safety design in single-lane tunnel infrastructure. Full article

Epileptic seizures arise from abnormally synchronized neural activity and remain a major global health challenge, affecting more than 50 million people worldwide. Despite advances in pharmacological interventions, a significant proportion of patients continue to experience uncontrolled seizures, underscoring the need for alternative neuromodulation strategies. Rhythmic neural entrainment has recently emerged as a promising mechanism for disrupting pathological synchrony, but most existing systems rely on complex analog electronics or high-power stimulation hardware. This study investigates a proof-of-concept digital custom-designed chip that generates a stable 6 Hz oscillation capable of imposing a stable rhythmic pattern onto digitized seizure-like EEG dynamics. Using a publicly available EEG seizure dataset, we extracted and averaged analog seizure waveforms, digitized them to emulate neural front-ends, and directly interfaced the digitized signals with digital output recordings acquired from the chip using a Saleae Logic analyser. The chip’s pulse train was resampled and low-pass-reconstructed to produce an analog 6 Hz waveform, allowing direct comparison between seizure morphology, its digitized representation, and the entrained output. Frequency-domain and time-domain analyses demonstrate that the chip imposes a narrow-band 6 Hz rhythm that overrides the broadband spectral profile of seizure activity. These results provide a proof-of-concept for low-power digital custom-designed entrainment as a potential pathway toward simplified, wearable neuromodulation device for future healthcare diagnostics. Full article

This study systematically investigates the effects of key process parameters in wire arc additive manufacturing (WAAM) on the surface morphology, geometric dimensions, microstructure, and microhardness of single-bead single-layer deposits fabricated from 2209 duplex stainless steel. Using a controlled variable approach, the influences of wire feed speed, travel speed, oscillation pattern, oscillation frequency, and oscillation amplitude on the deposition quality were examined. Experimental results indicate that wire feed speed and travel speed significantly affect the bead width, height, and fusion zone morphology, with optimal ranges identified as 4.5–6.5 m/min and 5–6 mm/s, respectively. Among the oscillation patterns, sinusoidal and figure-eight trajectories resulted in uniform deposition distribution and a refined microstructure, whereas the circular pattern led to fish-scale surface features and coarse grains. The optimal oscillation frequency and amplitude were determined to be 4 Hz and 4 mm, respectively, under which the deposits exhibited high surface quality, no defects other than the depression in the arc extinction zone, and the microhardness remains stable in the range of 280–290 HV. Comprehensive analysis indicates that investigating the influence of these process parameters on the morphology, microstructure, and hardness of DSS2209 single-bead deposits can effectively enhance the overall performance of WAAM-fabricated 2209 duplex stainless steel components, thereby providing a reliable foundation for subsequent multi-layer and multi-bead deposition. Full article

We present a numerical study comparing light scattering by small clusters composed of helices, capsules, and spheres. Using the discrete-dipole approximation (DDA), we compute orientation-averaged Mueller-matrix elements M₁₁, M₁₂, and M₁₄ for clusters with varying number of monomers (N = 5–45) and mean center-to-center separation (1–10 particle diameters). Our analysis isolates the influence of particle morphology on angular scattering intensity, linear polarization, and circular intensity differential scattering (CIDS), providing a direct comparison of symmetric and chiral shapes. Helices display persistent angular fine structure in M₁₁ and deep, side-scattering maxima in M₁₂, while spheres and capsules converge to smoother polarization curves with increasing separation. CIDS from symmetric monomers manifests as small oscillations around zero that decay rapidly with monomer separation and number. In contrast, helices produce a stable backward CIDS slope that is largely separation-independent but gradually flattens with increasing number of monomers. These trends confirm that morphology alone can influence key polarization characteristics and provide insights for interpreting scattering from complex-shaped particles. Such morphology-related features may help in the interpretation of polarization data in aerosol and planetary remote sensing and justify the refinement of the design of optical setups for studying irregular or chiral particles in controlled environments. Full article

Scalp high-frequency oscillations (HFOs) are promising noninvasive biomarkers of epileptogenicity, but their phenotypic diversity and clinical relevance in absence epilepsy (AE) remain unclear. This study aimed to classify scalp HFOs in AE using k-means clustering based on multiple morphological characteristics, and to evaluate their distribution across electroencephalogram (EEG) epochs and seizure control statuses. We analyzed scalp EEG recordings from 14 children and adolescents with AE. After excluding outliers, 163 scalp HFOs were characterized by average frequency, duration, amplitude, and number of cycles. Amplitude and cycle count were log-transformed prior to clustering, and k-means clustering was applied to identify distinct HFO phenotypes. Three clusters were identified: Cluster 1 (short duration, low amplitude), Cluster 2 (low frequency), and Cluster 3 (long duration, high cycle count). Cluster 2 and Cluster 3 were significant predictors of ictal HFOs in active AE, with odds ratios (ORs) of 0.33 (95% confidence interval [CI]: 0.14–0.74) and 5.00 (CI: 2.02–17.73), respectively. Cluster 2 also predicted interictal HFOs in active AE (OR [95% CI] = 2.71 [1.23–5.67]). These findings support the utility of scalp HFO phenotypes as EEG-based biomarkers for seizure detection and disease monitoring, potentially guiding treatment strategies in pediatric AE. Full article