Search Results (241)

Cotton, a globally significant crop grown in over 100 countries, sustains a $40 billion market and provides employment for over 350 million people worldwide. However, plastic contamination remains a persistent challenge within the industry, degrading cotton fiber quality and disrupting ginning. Manual inspection and optical machine-vision systems struggle when plastic fragments are concealed by fibers or lack sufficient color contrast. To address these challenges, we developed an ultrasonic phased-array imaging system operating at 40 kHz under field-programmable gate array (FPGA) control. Transmitter elements emit pulsed ultrasound along radial paths, separate reflection receivers record echo amplitudes to form acoustic images, and a set of transmission receivers captures signal attenuation, which is overlaid onto the reflection-based image to highlight potential contaminants. In preliminary laboratory-based tests on both seed cotton and lint samples, the system successfully detected visually obscured plastic fragments as small as $2\mathrm{cm}\times 2\mathrm{cm}$ with an angular resolution limit of $\pm 3^{\circ }$. Distinct reflection peaks and corresponding attenuation overlays were produced across the field of view, validating the system’s detection capabilities. These results demonstrate the feasibility of using ultrasonic imaging to reveal concealed plastics in cotton processing. Integrating this approach with existing optical methods could enhance contaminant-removal workflows and improve overall fiber quality and processing efficiency. Full article

Magnetorheological (MR) semi-active suspensions offer clear advantages in improving ride comfort and handling stability, yet their engineering applications are often hindered by strong nonlinear hysteresis of the damper, the randomness of road excitations, and the reliance on manual tuning of controller parameters. To address these issues, this paper proposes an integrated framework of “experimental modeling–semi-active implementation–adaptive control.” First, characteristic tests of the MR damper are conducted, based on which a current-dependent Bouc–Wen forward model is established. Tianji’s Horse Racing Optimization (THRO) is then employed for parameter identification to reproduce the hysteresis behavior accurately. Second, a back propagation (BP) neural network-based inverse current model is developed to achieve rapid mapping from “desired damping force” to “driving current,” enabling semi-active actuation. Furthermore, a radial basis function (RBF) neural network is embedded into the active disturbance rejection control (ADRC) structure to estimate the system Jacobian online and to tune key extended state observer (ESO) gains in real time, forming the proposed RBF-ADRC strategy and thereby enhancing disturbance observation and compensation capability. Simulation results under pulse-road and Class-C random-road excitations show that, compared with the passive suspension, the proposed method reduces the root mean square error values of sprung-mass acceleration, suspension dynamic deflection, and tire dynamic load by 25.14%, 18.71%, and 11.61%, respectively, while also outperforming skyhook control and fixed-gain ADRC. Frequency-domain results further show stronger attenuation in the low-frequency band relevant to body vibration. Under pulse excitation, RBF-ADRC yields smaller peak and trough body accelerations and faster post-impact recovery. Under ±30% sprung-mass variations, it achieves the best worst-case and fluctuation-range robustness among the compared strategies and remains close to offline retuning. These results demonstrate that the proposed method improves both control performance and robustness while reducing the need for repeated manual calibration. Full article

Flexible piezoelectric materials demonstrate broad application potential in wearable health monitoring, human–machine interaction, and biosensing. However, the piezoelectric response of pure PVDF-TrFE is limited and insufficient to meet the requirements for highly sensitive sensing. In this study, ZnO/PVDF-TrFE composite films with varying ZnO doping contents (3–11 wt%) were fabricated and systematically characterized in terms of their structural, thermal, and electrical properties. The results indicate that ZnO significantly promotes the formation of the polar β-phase in PVDF-TrFE, with the maximum β-phase content (F_β = 24.76%) and optimal piezoelectric performance achieved at 9 wt% ZnO doping. Devices based on this optimal composition exhibited stable ultrasonic transmission and reception capabilities under high-frequency pulse excitation, enabling sensitive detection of minor static pressure variations (e.g., contact pressure) through changes in ultrasonic echo signals, thereby realizing wearable conformity monitoring. Moreover, a sensor designed with a three-channel flexible substrate successfully captured human wrist pulse signals with high accuracy, demonstrating the practical utility and reliability of the device in flexible bio-electronic sensing applications. Full article

This work investigates the reactive crystallization of lithium carbonate (Li₂CO₃) by rapidly mixing concentrated aqueous solutions of LiCl (3.0–4.0 M) and Na₂CO₃ (1.5–2.0 M) at 65 °C, using focused beam reflectance measurement (FBRM) for online, in situ monitoring. The effect of low concentrations of poly(acrylic acid) (PAA), sodium hexametaphosphate (SHMP), and sodium tripolyphosphate (STPP) on nucleation and growth dynamics was systematically analyzed. The results show that the process is dominated by an intense initial supersaturation pulse, which governs early nucleation and subsequent population restructuring through growth and aggregation. Additives significantly modify the nucleation-growth coupling: PAA exhibits concentration- and time-dependent behavior, suppressing the detectable fines population and promoting consolidation into coarse fractions under high supersaturation; SHMP acts as a strong kinetic inhibitor, markedly reducing nucleation and, to a greater extent, growth; while STPP exhibits an intermediate, dose-dependent response, maintaining nucleation but limiting effective growth at high concentrations. Scanning electron microscopy observations confirm the formation of spherulitic Li₂CO₃ aggregates in all cases, with compactness and radial organization dependent on the additive. These results demonstrate that targeted additive selection allows for precise control of population dynamics and solid properties in reactive crystallization systems, within the investigated high-supersaturation concentration window, with useful mechanistic guidance for the design and control of Li₂CO₃ precipitation processes. Full article

Nicolau syndrome, also known as embolia cutis medicamentosa, is a rare iatrogenic reaction that may occur following parenteral drug administration, including inadvertent intra-arterial or periarterial injection. Its pathophysiology remains poorly understood; however, several mechanisms have been proposed, including vasospasm, embolization, cytotoxic inflammation, and secondary tissue necrosis. We report the case of a 22-year-old transgender woman who received intravenous benzathine penicillin in the left arm without a medical prescription following a reactive syphilis screening performed outside a formal healthcare setting. She subsequently developed severe pain, livedoid dermatitis, pallor, distal cyanosis, and blister formation. Radial and brachial pulses remained palpable, and Doppler ultrasonography revealed no evidence of arterial or venous thrombosis. Medical management included daily wound care, anticoagulation, corticosteroids, peripheral vasodilators, antibiotic therapy, and analgesia. The patient was hospitalized for nine days, with partial clinical improvement. However, persistent distal ischemic changes involving the second through fifth fingers raised concern for evolving necrosis and potential amputation. After counseling regarding these risks, the patient requested voluntary discharge. This case underscores the importance of safe medication administration and appropriate injection practices, particularly in low-resource settings. It also highlights the need for improved training of healthcare personnel to ensure early recognition and prompt management of Nicolau syndrome, as well as strengthened patient education to discourage self-medication and promote timely care by qualified healthcare professionals. Full article

Monitoring intracranial pressure (ICP) dynamics is critical for the management of traumatic brain injury, stroke, other neurosurgical conditions, and cerebral blood flow autoregulation; however, invasive ICP monitoring carries risks such as infection, hemorrhage, and sensor zero drift. Increasing evidence suggests that ICP waveform morphology provides clinically relevant information beyond mean ICP value alone. In this first-in-human prospective comparative clinical study, we evaluated the feasibility and accuracy of a novel, fully passive, non-invasive ICP pulse waveform monitoring system (Archimedes 02) based on the detection of eyeball mechanical movement. Fifteen intensive care unit patients (6 males, 9 females; mean age 57.1 ± 18.8 years) with clinically indicated invasive ICP monitoring or external ventricular drainage were enrolled. Three-minute monitoring sessions were performed to simultaneously acquire non-invasive ICP pulse waveforms, invasive ICP waveforms, and invasive radial artery blood pressure (ABP) waveforms. Averaged waveforms were derived for each patient and compared graphically and using correlation analysis. Non-invasive ICP pulse waves recorded with Archimedes 02 showed a strong correlation with invasive ICP waveforms ($\overline{\mathrm{R}}$ = 0.965). In contrast, correlations between non-invasive ICP and ABP waveforms ($\overline{\mathrm{R}}$ = 0.699), as well as between invasive ICP and ABP waveforms ($\overline{\mathrm{R}}$ = 0.749), were lower. These findings indicate that the non-invasive signal primarily reflects ICP dynamics rather than arterial blood pressure. This novel non-invasive ICP monitoring approach has the potential to enhance neurocritical care, particularly in settings where invasive monitoring is impractical or unavailable. Further validation in larger and more diverse patient populations is warranted. Full article

Background/Objective: Activity of SGK-1 has been associated with mechanical aspects of vascular remodeling and matrix stiffening has been a known characteristic of AAA. We hypothesis that VSMC-specific SGK-1 activity is vital to growth of AAA and contributes to progressive aortic stiffness. Methods: C57Bl/6 and SMC-SGK-1KO^+/− mice underwent AAA induction vs Sham on day 0. A subset of C57Bl/6 mice had pump implantation to treat with EMD638683. Aortic ultrasound images were obtained on Day 0 and Day 21 and analyzed for mechanical parameters. At terminal procedure the infrarenal aorta was harvested for immunoblot analysis. Results: At Day 21, C57Bl/6+AAA mice showed growth of 72.27% ± 2.2% versus the C57Bl/6+Sham (p < 0.0001) with associated 3.71 ± 1.15-fold increase in SGK-1 activity (p = 0.001). C57Bl/6+AAA+EMD mice demonstrated growth of 23.68% ± 2.82% (p = 0.0452) with no significant change in SGK-1 activity. SMC-SGK1-KO^+/−+AAA mice had growth of 28.20% ± 3.74% compared to SMC-SGK1-KO^+/−+Sham (p = 0.004) with increased SGK-1 activity (p = 0.0303). Radial strain was significantly reduced in the C57Bl/6+AAA (p = 0.0062) and C57Bl/6+AAA+EMD (p = 0.0135) when compared to C57Bl/6+Sham. Distensibility was significantly reduced in C57Bl/6+AAA (p = 0.01). Pulse propagation velocity (PPV) was significantly elevated in C57Bl/6+AAA mice (p < 0.0001) but inhibited by EMD therapy (p = 0.0007 vs. C57Bl/6+AAA). SMC-SGK1-KO^+/− +AAA mice showed significant reductions in radial strain (p = 0.0011) and distensibility (p = 0.0233) with a modest, but significant, increase in PPV (p = 0.0148). Conclusions: SGK-1 inhibition attenuated AAA growth and preserved vascular function. Targeting this pathway may provide a directed medical therapy for AAA and warrants further investigation. Full article

Air-shielding radial ultrasonic rolling electrochemical micromachining (AS-RUREMM) is proposed to fabricate high-quality micro-dimple textures on cylindrical SS304 surfaces while suppressing stray corrosion. In AS-RUREMM, an annular air sheath coaxially envelopes the electrolyte jet to confine the wetting footprint, and radial ultrasonic vibration is superimposed on a rolling cathode with micro-protrusions to intensify local mass transport and stabilize the interelectrode environment. A conductivity-centered theoretical framework is established to link air-sheathing-induced gas–liquid distribution, ultrasonic gap modulation, and the resulting current-density localization. Multiphysics simulations in COMSOL 5.3 clarify that moderate air pressure forms a stable confined gas–liquid structure that narrows the effective conductive pathway, whereas excessive air pressure increases intermittency and weakens effective gap conductivity. Experiments on SS304 tubes validate the confinement mechanism: compared with RUREMM, AS-RUREMM produces smaller pit width and depth but a higher depth-to-width ratio, indicating enhanced localization and reduced peripheral over-etching. The simulated cross-sectional profiles agree with measurements, with an overall deviation within 6%. Parameter studies identify an optimal operating window, and the combination of 0.18 MPa air pressure and 12 V pulse voltage provides the highest aspect ratio while maintaining stable machining. SEM/EDX analyses further support the improved process controllability under air shielding through reduced stray corrosion and composition changes consistent with a more regulated electrochemical dissolution environment. Full article

Optimizing the rectification and pressure loss controlled by the aperture structure is challenging, with particular attention paid to the problem of precisely modeling the rectification process of multilayer wire mesh in pulse tube cryocoolers. This work offers a rectifier design method based on the regularized orifice plate. A novel rectifier that reduces flow resistance and shows rectification performance comparable to a woven wire mesh is created by analyzing its effects on the flow using numerical simulation. Flow uniformity and pressure loss are selected as evaluation metrics. Point flow velocity calibration is performed under fully developed flow conditions to derive a quantitative equation relating voltage to flow velocity. A multi-cross-section radial flow velocity distribution test platform is set up. The experimental results show that the uniformity of woven wire mesh reaches 0.9670 under low-flow conditions and 0.9629 for the novel eight-ring rectifier, but the pressure drop reduction reaches 57.64%; the uniformity of the novel eight-ring rectifier is improved by 0.91~1.94% compared to that of woven wire mesh under high-flow conditions, and the pressure drop is reduced by 87.74~89.09%. The rectifier features uniformly distributed apertures, facilitating modeling and machining. Full article

When grinding silicon carbide, surface and subsurface damage have a significant impact on the product’s surface quality. One method to control the crack dimensions is laser irradiation on the SiC surface. The effect of this method on the grinding process is analyzed in this study. A series of experiments was carried out based on an orthogonal experimental design, with systematic adjustments made to laser parameters, including pulse energy (current), laser spot spacing, scanning times, and grinding process parameters. During the experiments, the grinding force was monitored by a dynamometer, and the specific grinding energy was calculated accordingly. Pulsed engraving laser modification effectively reduced the hardness of the ceramic surface layer by about 20%. The median and radial crack sizes induced by the laser in the subsurface layer ranged from 20.4 μm to 54.3 μm. This effectively inhibited further propagation of median and radial cracks during the grinding processes. Simultaneously, the tangential grinding force F_t was reduced by 30%. These conclusions were obtained through corresponding experiments that link surface roughness to laser power and grinding parameters. Using laser-induced controllable crack characteristics in the grinding process allow damage from surface and subsurface grinding to be controlled in brittle materials. Full article

Electrical discharge machining (EDM) is widely used for machining hard and difficult-to-cut materials; however, the complex and nonlinear nature of the process makes the accurate prediction of key performance indicators challenging, particularly when only limited experimental data are available. In this study, a combined Taguchi design and Gaussian process regression (GPR) modeling framework is proposed to predict the surface roughness (Ra), material removal rate (MRR), and overcut (OC) in die-sinking EDM. An L18 Taguchi orthogonal array was employed to efficiently design experiments involving discharge current, pulse duration, and electrode material. GPR models with an automatic relevance determination (ARD) radial basis function kernel were developed to capture nonlinear relationships and varying parameter relevance. Model performance was evaluated using strict leave-one-out cross-validation (LOOCV). The developed GPR models achieved low prediction errors, with RMSE (MAE) values of 0.54 µm (0.41 µm) for R_a, 1.56 mm³/min (1.21 mm³/min) for MRR, and 0.0065 mm (0.0055 mm) for OC, corresponding to approximately 9.8%, 5.4%, and 5.9% of the respective response ranges. These results confirm stable and reliable predictive accuracy within the investigated parameter domain. Based on the validated surrogate models, multi-objective optimization was performed to identify Pareto-optimal process conditions, revealing graphite electrodes as the dominant choice within the feasible operating region. The proposed approach demonstrates that accurate and robust prediction of EDM performance can be achieved even with compact experimental datasets, providing a practical tool for process analysis and optimization. Full article

The unique features of annular phased array transducers, such as ring-shaped elements and the concentric configuration, cause them to behave differently from commonly used linear array transducers, in terms of sound field distribution and pulse–echo response. Consequently, standard techniques for assessing linear array transducers can introduce significant errors when applied to annular array transducers, especially concerning element-to-element sensitivity variance. This study investigates the consistency of element sensitivity in annular phased array transducers. Through theoretical analysis, a Long-Belt source assumption model was developed based on the Rayleigh integral to characterize the responses of ring-shaped elements in an analytical and explicit form. The model suggests that the response amplitude is linearly correlated with the radial width of the element, which was validated by subsequent numerical simulations. Based on these findings, a modified sensitivity evaluation algorithm for annular array transducers is presented. The response voltage per unit width, rather than the total response voltage, is used to eliminate the influence of varying geometries and sizes across elements. The sensitivity variation of a 32-element annular array transducer was evaluated using the new algorithm. Compared to the uncorrected measurement, the maximum sensitivity variation was reduced significantly from 25 dB to 6 dB, revealing the transducer’s intrinsic consistency despite the different geometric features of each element. Due to its distinct geometry compared to the ring-shaped elements, the central element cannot be corrected or evaluated using this method. These results suggest that the proposed algorithm enables the more accurate evaluation of sensitivity consistency for annular phased array transducers, thereby improving measurement reliability in practical applications. Full article

This review provides a comprehensive overview of modern experimental and numerical methods for characterizing the sound absorbing properties of dissipative sound-absorbing materials. Experimentally, we summarize both in situ techniques (e.g., pulse reflection, two-microphone, p-u probe, and spatial Fourier transform method) and laboratory methods (e.g., impedance tube, transfer function, and reverberation room methods), discussing their principles and applications. For the numerical methods, we detail the development and refinement of empirical models (e.g., Delany–Bazley, Miki, Komatsu), theoretical models (e.g., Johnson–Champoux–Allard), and computer numerical methods, along with methods for obtaining flow resistivity, including empirical formulas, experimental measurements. Furthermore, we review recent advances in machine learning approaches (e.g., generalized regression neural networks, radial basis function neural networks, and artificial neural networks) for predicting the sound absorption coefficient. This work aims to serve as a methodological reference for the research, development, and performance evaluation of dissipative sound-absorbing materials. Full article

Background: The analysis of gunshot residue (GSR) is crucial for gaining information on how a crime occurred. This study presents an innovative proof of concept for measuring shooting distances by performing Flash-Pulse active Thermography (FPT). Compared to conventional chemical methods, FPT offers a significant advantage by digitalizing the residue pattern in a non-destructive manner. Methods: Thermal images of cotton canvases, both white and colored, were analyzed to quantify the distribution of gunshot residues after shooting from several distances, specifically focusing on smoke and semi-burnt powders. The proposed approach uses contrast and radial intensity profiles to extract exponential coefficients, which are dependent on the shooting distance. Results: Employing a sigmoid model to fit the coefficients over distance and to derive a characteristic feature used as a classification metric, firing distances can be classified into short, medium, and long range and can be predicted with an uncertainty of less than 5 cm for distances between 18 and 38 cm under the tested conditions. Considerations regarding the influence of different weapons and ammunition are reported, suggesting the potential for a general approach. Conclusions: The methodology has been validated on several samples, demonstrating its feasibility for specific forensic applications. Its most robust use is as a weapon- and ammunition-specific calibration tool, supporting case-specific distance estimation analysis. Full article

This paper presents results from active flow control experiments carried out on a single stage axial compressor. The flow under various forced conditions has been investigated using 2D 2C particle image velocimetry (PIV) on three radial planes along the blades’ span and two different operating points corresponding to the minimum mass flow at which the compressor naturally stalls, and to the lower stability limit reached with the control system activated. In particular, a control strategy using continuous blowing is compared with a pulsed one using the same injected mass flow. Comparison is performed with the base flow without control (when available), or with each other, based on the PIV results in the form of relative velocity maps or inlet/outlet flow characteristics. Full article