Search Results (76)

We present the first aero-structural evaluation of a 3 m-diameter hybrid wind-PV rotor employing flat-plate blades stiffened by a peripheral ring. Owing to the lack of prior data, we combine low-Reynolds BEM, elastic FEM sizing, and steady-state CFD (k-ω SST) to build a coherent preliminary load and performance dataset. After upsizing the hub pins (Ø 30 mm), ring (50 × 50 mm) and spokes (Ø 40 mm), von Mises stresses stay below 25% of the 6061-T6 yield limit and tip deflection remains within 0.5% R across Cut-in (3 m/s), Nominal (5 m/s) and Extreme (25 m/s) wind cases. CFD confirms a flat efficiency plateau at λ = 2.4–2.8 (β = 10°) and zero braking torque at β = 90°, validating a three-step pitch schedule (20° start-up → 10° nominal → 90° storm). The study addresses only the rotor; off-the-shelf generator, brake, screw-pitch and azimuth/tilt drives will be integrated later. These findings set a solid baseline for full-scale testing and future transient CFD/FEM iterations. Full article

In response to the urgent need for full-process mechanization in Xinjiang’s cotton–cumin intercropping system, and to address the prominent bottlenecks of missing equipment for key harvesting steps and reliance on manual operations, we developed a cumin harvester and investigated its operating mechanisms. Guided by the agronomic parameters of the intercropping system, we executed a system-level design centered on the header unit, performed multi-objective optimization using orthogonal experiments and regression modeling, and conducted field validation. Results show: stubble height of 32.6 mm, harvester reel speed of 28 r/min, and forward speed of 3.26 km/h. Under this parameter configuration, the harvest rate was 89.54%, and the average damage rate was 7.33%. Field trials indicated a harvest rate of 88.2% and an average damage rate of 5.6%, with deviations from model predictions of 1.34% and 1.73%. The optimal reel index (λ = 1.69), the longitudinal component of the reel tine motion, prevents repeated impacts on the plants, reducing shattering and threshing damage; the axial component provide reliable support and smooth guidance to the stalks, ensuring continuous, steady cutting; the optimized stubble height is lower than the plant’s center of mass. Full article

Hospitals must allocate beds and staff effectively under volatile arrival patterns, where scheduling errors can cause preventable harm. This study introduces a fairness-aware, forecast-informed reinforcement learning framework for hospital scheduling, explicitly integrating fairness constraints, short-term demand forecasts, and SHAP-based explainability. The state fuses patient and system context with short-horizon demand forecasts, mean arrivals ($\widehat{\lambda }$), and volatility (${\widehat{\sigma }}^2$). The reward jointly optimizes efficiency, equity, and safety by penalizing waiting, diversions/transfers, ICU misuse, overtime, and cross-ward disparity. Using a benchmark-aligned synthetic cohort (60k visits over one year), the approach is compared against First-Come-First-Served (FCFS) and ablations without forecast features. The learned policy halves the mean waiting time (from 215.3 to 102.5 min), reduces diversions/transfers (from 27.6% to 7.8%), improves ICU match accuracy (from 93.4% to 95.1%), raises the fairness index by 45%, and cuts staff overtime by 56%. Adding forecast signals yields further gains over forecast-naive DQN (9% shorter waits; 28% fewer diversions/transfers), with robustness under demand surges and triage-mix shifts. By unifying equity constraints, anticipatory context, and explanation, the method turns reactive queues into proactive, auditable control and is extensible to perioperative flow, disaster triage, and outpatient capacity management. Full article

This paper investigates a new class of two-dimensional fuzzy difference equations that integrate logarithmic nonlinearities with interaction effects between system variables. Motivated by the need to model complex dynamical systems influenced by uncertainty and interdependencies, we propose a system that extends existing one-dimensional models to capture more realistic interactions within a discrete-time framework. Our approach employs the characterization theory to transform the fuzzy system into an equivalent family of classical difference equations, thereby facilitating a rigorous analysis of the existence, uniqueness, and boundedness of positive solutions. To support the theoretical findings, two numerical examples are provided, illustrating the model’s capacity to capture complex dynamical patterns under fuzzy conditions. An application to a fuzzy population growth model illustrates how the model captures both interaction effects and uncertainty while ensuring well-defined and stable solutions. Numerical simulations show that, for instance, with $\alpha =0.10$, $\beta =\delta =1.0$, $\gamma =0.08$, and ${\rho }_x={\rho }_y=0.10$, the trajectories of $(x_t,y_t)$ rapidly converge toward a stable fuzzy equilibrium, with uncertainty bands confirming the positivity and boundedness of the solutions. Full article

Introduction: Expanded hemodialysis using medium cut-off (MCO) dialyzers effectively removes middle-molecule uremic toxins, comparable to hemodiafiltration, but their single-use designation increases the dialysis costs. This study evaluated the efficacy and safety of reusing two MCO dialyzers available in Thailand. Methods: In this randomized controlled trial, hemodialysis patients were assigned to receive treatment with either Theranova^® 500 or Elisio^® 21HX dialyzers. Each dialyzer was reprocessed using peracetic acid and reused for up to 15 sessions. Dialyzer performance was assessed by the reduction ratios (RRs) of solutes, including β2-microglobulin (β2-MG), kappa and lambda free light chains (κ-FLC, λ-FLC), and interleukin-6 (IL-6), at baseline and the 2nd, 5th, 10th, and 15th sessions. Results: Forty-eight patients were enrolled (mean age 63.6 ± 13.7 years; 62.5% male) and randomized into 2 groups with comparable baseline characteristics. RRs for β2-MG, κ-FLC, and λ-FLC were similar between the groups and declined modestly over time after dialyzer reused (β2-MG: 78.2% to 72.5% vs. 77.2% to 74.5%, κ-FLC: 64.6% to 51.3% vs. 58.9% to 49.5%, and λ-FLC: 51.2% to 46.4% vs. 49.4% to 39.2% in the Theranova^® 500 and Elisio^® 21HX groups, respectively). Theranova^® 500 demonstrated significantly higher IL-6 clearance in the 2nd (29.9% vs. 16.0%; p = 0.018) and 5th (23.8% vs. 7.7%, p = 0.031) sessions. It also showed a non-significant trend toward lower dialyzer survival (HR 3.98; p = 0.085) and higher, though clinically acceptable, albumin loss (mean difference 0.56 g/session; p < 0.001), which decreased with reuse. Conclusions: Both MCO dialyzers demonstrated comparable overall performance during reuse. Theranova^® 500 provided better IL-6 clearance with manageable albumin loss. Implementation of high-quality dialyzer reuse protocols may optimize clinical efficacy and patient outcomes while balancing cost, accessibility, and environmental considerations. Full article

In the slow tool servo (STS) turning technology for optical lenses, the D-shaped toolpath can improve the quality of the optical surfaces of off-axis aspheric and cylindrical microlens arrays. However, the traditional D-shaped toolpath has the problem of excessive servo following error in the X-axis. To address this issue, the projection of the D-shaped toolpath in the XZ plane is divided into a cutting zone and a transition zone. In the transition zone, an equation system based on continuity constraints (surface height, feed-rate, acceleration) is established. By solving this system of equations, a toolpath can be obtained along which the feed-rate of the X-axis varies smoothly. An example shows that the acceleration of the X-axis of the lathe is reduced by 84% compared to the traditional D-shaped toolpath. In the XZC interpolation mode, the spindle velocity of the C-axis changes smoothly. An off-axis spherical surface and an integral mirror have been machined using the optimized D-shaped toolpath. The X-axis servo following error of the lathe during processing is within 7 nm, and the surface shape accuracy reaches 0.361λ at 632.8 nm. This method enables high-precision processing of off-axis curved surfaces and cylindrical arrays. Full article

In this study, a novel direct laser beam turning (DLBT) approach is proposed for the precision machining of AISI 308L austenitic stainless steel, which eliminates the need for cutting tools and thereby eradicates tool wear and vibration-induced surface irregularities. A nanosecond-pulsed Nd:YAG fiber laser (λ = 1064 nm, spot size = 0.05 mm) was used, and Ø1.6 mm × 20 mm cylindrical rods were processed under ambient conditions without auxiliary cooling. The experimental framework systematically evaluated the influence of scanning speed, pulse frequency, and the number of laser passes on dimensional accuracy and material removal efficiency. The results indicate that a maximum diameter reduction of 0.271 mm was achieved at a scanning speed of 3200 mm/s and 50 kHz, whereas 0.195 mm was attained at 6400 mm/s and 200 kHz. A robust second-order polynomial correlation (R² = 0.99) was established between diameter reduction and the number of passes, revealing the high predictability of the process. Crucially, when the scanning speed was doubled, the effective fluence was halved, considerably influencing the ablation characteristics. Despite the low fluence, evidence of material evaporation at elevated frequencies due to the incubation effect underscores the complex photothermal dynamics governing the process. This work constitutes the first comprehensive quantification of pass-dependent diameter modulation in DLBT and introduces a transformative, noncontact micromachining strategy for hard-to-machine alloys. The demonstrated precision, repeatability, and thermal control position DLBT as a promising candidate for next-generation manufacturing of high-performance miniaturized components. Full article

FeGa alloys with small additions of rare-earth elements surpass binary alloys in magnetostriction and plasticity. For this reason, they are considered promising magnetostrictive materials for various electrical engineering applications. The alloy (Fe₈₁Ga₁₉)_99.8Ce_0.2 was prepared and investigated in this work. It was found that in the cast state, it has a magnetostriction of 3/2 λ about 100 ppm, saturation magnetization of 150 emu/g, tensile strength of about 300 MPa, and fracture strain of 3%. The microstructure, crystallographic texture, and behavior when heated of the alloy were investigated. Then the ingot was subjected to forging and hot rolling with a deformation degree of 90% at 1000 °C. The structure and mechanical properties of samples cut from a hot rolling sheet were studied. Their tensile strength and fracture strain increase compared to cast state up to 600 MPa and 4% correspondingly. Full article

As two major pests of cowpea in South China, bean flower thrips [Megalurothrips usitatus (Bagnall)] and flower thrips [Frankliniella intonsa (Trybom)] always occur on the same plant. In this study, the two-sex life table parameters of these two species were investigated on three bean pods: cowpea (Vigna unguiculata L. var. Chunqiu Wujiadou), snap bean (Phaseolus vulgaris L. var. Yonglong 3), and green bean (Phaseolus vulgaris L. var. Linghangzhe) using standard cut bean protocols. Longevity of female adult M. usitatus showed no significant difference on cowpea and snap bean, but was shortest on green bean, with the highest fecundity on snap bean, followed by cowpea and green bean. Longevity and fecundity of female adult F. intonsa were both highest on cowpea, followed by snap bean and green bean. On snap bean, the population parameters (R₀, GRR, T) of M. usitatus were higher than F. intonsa, whereas r and λ were not different, suggesting that M. usitatus were more competitive on snap bean. On cowpea, the population parameters (R₀, GRR, r, λ) of F. intonsa were higher than M. usitatus, suggesting a competitive advantage of F. intonsa on cowpea. To better mimic field conditions, we investigated the survival and fecundity of adult M. usitatus under two distinct scenarios: when they could feed directly on cut surfaces of cowpeas (standard lab protocol), and when they could not. Adult survival of M. usitatus is not significantly influenced by whether or not they fed directly on cut surfaces of cowpeas. However, a notable decrease in fecundity was observed in M. usitatus that fed on surface-covered cut pods. This suggested that direct feeding on cut surfaces of cowpea did have an impact on thrips’ fecundity, offering fresh perspectives for future research into the growth and development of thrips in a laboratory. Our study suggests that experiments involving cut surfaces may be misleading, and further investigations are ongoing to address these concerns. Full article

The market demand for black polyimide (BPI) has grown hugely in the field of flexible copper-clad laminates (FCCLs) as a replacement for transparent yellow polyimide. The 3,6-bis(thiophen-2-yl)diketopyrrolopyrroles (TDPP) derivative is recognized for its high molar extinction coefficient. In this research, we have synthesized a diamine monomer named 3,6-bis[5-(4-amino-3-fluorophenyl)thiophen-2-yl]-2,5-bis(2-ethylhexyl)pyrrolo[4,3-c]pyrrole-1,4-dione (DPPTENFPDA), featuring a TDPP unit attached by fluorinated benzene rings. The subsequent reaction of DPPTENFPDA with pyromellitic dianhydride (PMDA) yielded an inherent BPI (DPPTENFPPI). By introducing chromophores derived from TDPP, the light absorption spectrum of DPPTENFPPI was broadened and red-shifted, thereby achieving full absorption within the visible spectrum and producing a highly black color that has a cut-off wavelength (λ_cut) of 717 nm and a CIE-Lab coordinate L* of 0.86. Additionally, DPPTENFPPI exhibited a low coefficient of thermal expansion (CTE) and remarkable thermal and electrical performance. Density functional theory calculations were conducted to explore the electronic nature of DPPTENFPPI. The outcomes revealed that the excellent light absorption of DPPTENFPPI predominantly originates from the transition from HOMO to LUMO + 1 within the chromophore moiety. The FCCL made from DPPTENFPPI films has high solder heat resistance and peel strength. This research contributes valuable insights into the structure and design of high-performance intrinsically black PIs for microelectronics applications. Full article

The rise of CubeSats has unlocked opportunities for cutting-edge space missions with reduced costs and accelerated development timelines. CubeSats necessitate a high-gain antenna that can fit within a tightly confined space. This paper is primarily concerned with designing a compact Ku-band offset cylindrical reflector antenna for a CubeSat-based Earth Observation mission, with the goal of monitoring Arctic snow and sea ice. The development of a Ku-band offset cylindrical reflector, with a compact aperture of 110 × 149 mm² (6.3λ × 8.5λ), is described alongside a patch array feed consisting of 2 × 8 elements. The patch array feed is designed using a lightweight Rogers substrate and is utilized to test the reflector. Adopting an offset configuration helped prevent gain loss due to feed blockage. Analyzing the reflector antenna, including the feed, thorough simulations and measurements indicates that achieving a gain of 25 dBi and an aperture efficiency of 52% at 17.2 GHz is attainable. The reflector’s cylindrical shape and compact size facilitate the design of a simple mechanism for reflector deployment, enabling the antenna to be stored within 1U. The array feed and reflector antenna have been fabricated and tested, demonstrating good consistency between the simulation and measurement outcomes. Full article

The strange baryon production in Bi + Bi collisions at $\sqrt{s_{NN}}=9.0$ GeV is studied using the PHSD transport model. Hyperon and anti-hyperon yields, transverse momentum spectra, and rapidity spectra are calculated, and their centrality dependence and the effect of rapidity and transverse momentum cuts are studied. The rapidity distributions for $\overline{\mathsf{\Lambda }}$, $\mathsf{\Xi }$, $\overline{\mathsf{\Xi }}$ baryons are found to be systematically narrower than for $\mathsf{\Lambda }$s. The $p_T$ slope parameters for anti-hyperons vary more with centrality than those for hyperons. Restricting the accepted rapidity range to $\left|y\right|<1$ increases the slope parameters by 13–30 MeV, depending on the centrality class and the hyperon mass. Hydrodynamic velocity and vorticity fields are calculated, and the formation of two oppositely rotating vortex rings moving in opposite directions along the collision axis is found. The hyperon spin polarization induced by the medium vorticity within the thermodynamic approach is calculated, and the dependence of the polarization on the transverse momentum and rapidity cuts and on the centrality selection is analyzed. The cuts have stronger effect on the polarization of $\mathsf{\Lambda }$ and $\mathsf{\Xi }$ hyperons than on the corresponding anti-hyperons. The polarization signal is maximal for the centrality class, 60–70%. We show that, for the considered hyperon polarization mechanism, the structure of the vorticity field makes an imprint on the polarization signal as a function of the azimuthal angle in the transverse momentum plane, ${\varphi }_H$, $cos{\varphi }_H=p_x/p_T$. For particles with positive longitudinal momentum, $p_z>0$, the polarization increases with $cos{\varphi }_H$, while for particles with $p_z<0$ it decreases. Full article

An interdigital transducer structure was fabricated from multilayer graphene on the surface of the $YZ$-cut of a LiNbO₃ ferroelectric crystal. The multilayer graphene was prepared by CVD method and transferred onto the surface of the LiNbO₃ substrate. The properties of the multilayer graphene film were studied by Raman spectroscopy. A multilayer graphene (MLG) interdigital transducer (IDT) structure for surface acoustic wave (SAW) excitation with a wavelength of $\Lambda =60$ μm was fabricated on the surface of the LiNbO₃ crystal using electron beam lithography (EBL) and plasma chemical etching. The amplitude–frequency response of the SAW delay time line was measured. The process of SAW excitation by graphene IDT was visualized by scanning electron microscopy. It was demonstrated that the increase in the SAW velocity using graphene was related to the minimization of the IDT mass. Full article

Piezoelectric c-axis oriented zinc oxide (ZnO) thin films, from 1.8 up to 6.6 µm thick, have been grown by the radio frequency magnetron sputtering technique onto fused silica substrates. A delay line consisting of two interdigital transducers (IDTs) with wavelength λ = 80 µm was photolithographically implemented onto the surface of the ZnO layers. Due to the IDTs’ split-finger configuration and metallization ratio (0.5), the propagation of the fundamental, third, and ninth harmonic Rayleigh waves is excited; also, three leaky surface acoustic waves (SAWs) were detected travelling at a velocity close to that of the longitudinal bulk wave in SiO₂. The acoustic waves’ propagation in ZnO/fused silica was simulated by using the 2D finite-element method (FEM) technique to identify the nature of the experimentally detected waves. It turned out that, in addition to the fundamental and harmonic Rayleigh waves, high-frequency leaky surface waves are also excited by the harmonic wavelengths; such modes are identified as Sezawa waves under the cut-off, hereafter named leaky Sezawa (LS). The velocities of all the modes was found to be in good agreement with the theoretically calculated values. The existence of a low-loss region in the attenuation vs. layer thickness curve for the Sezawa wave below the cut-off was theoretically predicted and experimentally assessed. Full article

This research proposes a miniature circular polarization antenna used in a wireless capsule endoscopy system at 2.45 GHz for industrial, scientific, and medical bands. We propose a method of cutting a chamfer rectangular slot on a circular radiation patch and introducing a curved radiation structure into the centerline position of the chamfer rectangular slot, while a short-circuit probe is added to achieve miniaturization. Therefore, we significantly reduced the size of the antenna and made it exhibit circularly polarized radiation characteristics. A cross-slot is cut in the GND to enable the antenna to better cover the operating band while being able to meet the complex human environment. The effective axis ratio bandwidth is 120 MHz (2.38–2.50 GHz). Its size is π × 0.032λ₀² × 0.007λ₀ (where λ₀ is the free-space wavelength of at 2.4 GHz). In addition, the effect of different organs such as muscle, stomach, small intestine, and big intestine on the antenna when it was embedded into the wireless capsule endoscopy (WCE) system was further discussed, and the results proved that the WCE system has better robustness in different organs. The antenna’s specific absorption rate can follow the IEEE Standard Safety Guidelines (IEEE C95.1-1999). A prototype is fabricated and measured. The experimental results are consistent with the simulation results. Full article