Search Results (113)

A novel wavelength-selective absorber is numerically designed and analyzed using a three-dimensional finite-difference time-domain method. The proposed solar thermal absorber consists of an array of asymmetric tungsten ring nanowires deposited on a tungsten thin film. This structure achieves high solar absorption efficiency (78.5%) and low thermal emissivity (5%) at 100 °C, resulting in a photothermal conversion efficiency of 73.55% under standard solar illumination. The selective absorption arises from the excitation of magnetic polaritons and surface plasmon polaritons. To further elucidate the physical mechanisms behind the spectral response, an equivalent inductor–capacitor circuit model is employed. The absorber also exhibits polarization-insensitive and angle-independent performance up to 50° for both transverse magnetic and transverse electric polarizations. These results demonstrate the potential of the proposed metamaterial absorber for advanced applications in solar energy harvesting, photothermal conversion, and thermal emission. Full article

Background: Random pattern flaps are widely used in reconstructive surgery when inadequate vascularity precludes skin graft survival or when regional pedicled flaps are unavailable due to local burn injury. Here, thin tissue from the upper arm was utilized to cover exposed cartilage over the proximal interphalangeal (PIP) joints of the contralateral hand. Methods/Technical Note: We report the uncommon application of multiple cross-arm (Colson) flaps to reconstruct dorsal skin defects over the PIP joints of the index, middle, and ring fingers following a high-voltage burn injury, in conjunction with a comprehensive literature review. Results: Three separate random-pattern flaps were harvested from the upper arm and transferred to the contralateral hand. All flaps demonstrated good perfusion, durable coverage, and a clean wound bed postoperatively, with preservation of joint mobility. Conclusions: To our knowledge, this represents one of the first reported reconstructions of multiple adjacent PIP joints using individual cross-arm flaps. This technique remains a dependable salvage option that should be considered in complex reconstructive scenarios when local or microsurgical options are not feasible. Full article

To address longstanding challenges in sea buckthorn harvesting—such as the absence of effective harvesting principles, inefficient traditional manual and semi-mechanised methods, and rising labour costs—this study developed a self-propelled harvester equipped with a reciprocating cutter. The harvester featured an optimised double-support reciprocating cutter driven by a swing ring mechanism, with its kinematic parameters and cutting speed determined through analytical analysis. A coordinated transport system, consisting of an arc-shaped branch dial wheel, a conveying device, and a hydraulic system, was also designed. Field experiments were conducted employing a three-factor, three-level Box–Behnken design of Response Surface Methodology (RSM), which enabled the establishment of a predictive mathematical model for harvesting performance. Numerical optimisation via the model yielded the optimal operational parameters: harvesting forward speed of 0.6 m·s⁻¹, a cutting speed of 1.2 m·s⁻¹, and a conveyor belt linear speed of 0.8 m·s⁻¹. With this parameter combination, the missed cutting rate was 6.72%, fruit breakage rate 4.06%, and conveyor failure rate 7.79%, all meeting mechanised harvesting standards. This research provides the essential theoretical foundation and technical solutions for harvesting equipment in the sea buckthorn industry, accelerating its mechanisation process. Full article

This paper presents a three-phase powerline energy harvesting circuit with doubly regulated output voltages to power wireless sensors for the monitoring of railroad powerline status. Three ring-shaped silicon steel cores coupled to the three phases of a powerline convert the line current into three-phase voltages, which are applied to an energy harvesting circuit. The key parts of the circuit are a series three-phase voltage rectifier, a buck–boost converter operating in discontinuous conduction mode (DCM), and a microcontroller unit (MCU) for maximum power point tracking (MPPT). The MCU performs two-step MPPT, coarse and fine, for impedance matching based on the perturb and observe method. Two parallel voltage regulators deliver 5 V and 5.7 V regulated DC voltages to power a radio and a set of sensors, respectively. The energy harvesting circuit is prototyped using commercial-off-the-shelf (COTS) components on an FR4 PCB. The measured maximum efficiency is 84% for the three-phase voltage rectifier and 89% for the buck–boost converter under the powerline current ranging from 5 A to 20 A. Full article

Postharvest diseases caused by various fungal pathogens pose a significant threat to fruit quality, storage, and market value, making their identification and biological characterization essential for effective management strategies. This study examines the morphological and phylogenetic characteristics of Alternaria, Botryosphaeria, Pestalotiopsis, and Trichothecium species associated with loquat fruit rot in Yunnan, China. In May 2023, fruit rot of loquat in Yunnan, China, was classified into four types: ring rot, brown spot, black spot, and soft rot, with incidence rates of 4%, 6%, 6%, and 12%, respectively. Based on morphological features and molecular approaches, two strains of Botryosphaeria were identified as Botryosphaeria dothidea, which causes ring rot. Three strains of Trichothecium were identified as Trichothecium roseum, which is responsible for the brown spots. Three strains of Alternaria were identified as Alternaria alternata, which led to the appearance of black spots on the leaves. Similarly, two strains of Pestalotiopsis were identified as Pestalotiopsis kenyana, which causes soft rot. All identified species were verified to induce harvest loquat fruit rot by validating Koch’s postulates. This is the novel report of B. dothidea, T. roseum, and P. kenyana inducing postharvest fruit rot on loquat in Yunnan, China, and globally. It is also the first evidence that A. alternata causes postharvest fruit rot and gray leaf spot on loquat in Yunnan, China. The virulence differed among species, even within isolates of the same species. Additionally, the effect of temperature on the pathogenicity of A. alternata on loquat leaves was more than humidity. These findings enhance our understanding of the fungal pathogens affecting loquat fruit in the study area and highlight the importance of effective management strategies to minimize fruit rot. Further research is needed to investigate the ecological impacts of these species and potential control measures in agricultural practices. Full article

Zearalenone (ZEN) is a widespread estrogenic mycotoxin that poses serious health risks to both humans and animals through the contamination of cereals and feeds. In this study, a novel Bacillus strain X13 was isolated from volcanic rock soil and demonstrated the unique ability to utilize ZEN as the sole carbon source for growth and metabolism. Under optimized conditions (37 °C, pH 8.0, and 5% inoculum in M9 minimal medium), strain X13 achieved a ZEN degradation efficiency of 98.57%. LC-MS analysis identified 1-(3,5-dihydroxyphenyl)-6′-hydroxy-1′-undecen-10′-one as the primary degradation product, indicating enzymatic hydrolysis of the lactone ring. Enzymatic assays revealed that the active components were extracellular, proteinaceous, and metal ion-dependent. Furthermore, the strain reduced ZEN content in mold-contaminated corn flour by 74.6%, effectively lowering toxin levels below regulatory limits. These findings suggest that Bacillus sp. X13 is a promising candidate for the bioremediation of ZEN-contaminated agricultural products, with significant potential for application in food and feed detoxification strategies. The robust degradation performance of strain X13 under simulated environmental conditions, combined with its adaptability to agricultural substrates, positions it as a viable solution for large-scale mycotoxin mitigation in the food industry chain, from pre-harvest field management to post-harvest storage processing. Full article

Wireless structural health monitoring is needed for machine elements of which the working motions prevent wired monitoring. Rotating machine shafts are such elements. Wired monitoring of the rotating shaft requires making significant changes to the shaft structure, primarily drilling a hole in the longitudinal axis of the shaft and installing a slip ring assembly at the end of the shaft. Such changes to the shaft structure are not always possible. This paper proposes the use of piezoelectric energy harvesting from a rotating shaft to power wireless temperature monitoring of the shaft surface. The main components of presented wireless temperature monitoring are three piezoelectric composite patches, three thermal fuses, a system for storing and distributing the harvested energy, and a radio transmitter. This article contains the results of experimental research of such wireless monitoring on a dedicated laboratory stand. This research included four connections of piezoelectric composite patches: delta, star, parallel, and series for different capacities of a storage capacitor. Based on experimental results, three parameters that influence the frequency of sending data packets by the presented wireless temperature monitoring are identified: amplitude of stress in the rotating shaft, rotation speed of the shaft, and the capacity of a storage capacitor. Full article

Topping is an essential step in cotton cultivation in Xinjiang, China, which can effectively increase the number of bolls per plant and optimize the yield and quality. Paclobutrazol, as a common chemical topping agent for cotton, faces challenges such as unstable topping effect and limited leaf surface absorption during application. In this study, paclobutrazol was used as the ligand and a zinc complex was synthesized by the thermosolvent method to replace paclobutrazol and improve the topping effect on cotton. The structure of the complex was characterized using FTIR, UV-vis, TG, and XRD analyses. The results confirmed that each zinc ion coordinated with four nitrogen atoms from the triazole rings of paclobutrazol and two oxygen atoms from nitrate ions, forming an octahedral geometry. Surface tension measurement and analysis revealed that the complex had a surface tension reduction of 12.75 mN/m compared to paclobutrazol, thereby enhancing the surface activity of the complex in water systems and improving its absorption efficiency on plant leaves. Two-year field trials indicated that the foliar application of the complex at a dosage of 120 g·hm⁻² in inhibiting cotton plant height was more stable to that of paclobutrazol or mepiquat chloride. It also shortened the length of fruiting branches, making the shape of cotton plants compact, thereby indirectly improving the ventilation and light penetration of the cotton field and the convenience of mechanical harvesting. Yield data showed that, compared with artificial topping, the complex at a dosage of 120 g·hm⁻² treatment increased cotton yield by approximately 4.6%. Therefore, the paclobutrazol–zinc complex is a promising alternative to manual topping and have great application potential in future mechanized cotton production. Full article

This paper presents an electromagnetic translational–rotary motion impact energy harvester based on a magnetic cylinder rotated around a fixed magnetic ring. It is beneficial for capturing impact energy generated by natural human motions, such as clapping, boxing, and stomping. The energy harvester consists of a circular housing, twelve coils, a magnetic cylinder, and a magnetic ring. Once activated, the magnetic cylinder revolves and rotates around the magnetic ring, inducing a significantly large electromotive force across the twelve coils. According to Faraday’s law, the output voltage generated by the coils is proportional to the turns, enabling the efficient harvesting of biomechanical waste energy. Moreover, the energy harvester can convert translational motion from any orientation into a multi-circle rotational motion of the low-damping magnetic cylinder, which passes through twelve coils and applies a variable magnetic field across them. During a single excitation event, the prototype harvester was able to charge a 470 μF, 25 V capacitor to over 0.81 V in just 39.5 ms. The energy output and effective average power were calculated to exceed 0.15 mJ and 3.80 mW, respectively. Full article

For complex mechanical transmission equipment, shaft bearings are usually enclosed together with the shaft in the internal space of the housing to maintain good sealing and reliability. However, it is difficult to monitor the status of the shaft bearing through external sensors on the housing, while internal sensors face challenges in energy supply and data transmission. Therefore, a piezoelectric transducer ring-based energy harvesting microelectromechanical system (PTR-EH-MEMS) is proposed for the condition monitoring of shaft bearings. Specifically, the piezoelectric transducer ring is designed to convert mechanical vibrations into electrical energy, which simultaneously acts as a self-powered monitoring sensor through energy harvesting. In addition, the MEMS is embedded for piezoelectric data processing and condition monitoring of the shaft bearings. To verify the proposed PTR-EH-MEMS, an experimental investigation is implemented under different conditions. The experimental results demonstrate that the system can achieve the maximum DC output of 0.8 V and the root mean square power of 43.979 μW within 128 s, which can effectively identify early-stage bearing faults frequency through a self-powered mode. By combining energy harvesting with condition monitoring capability, the PTR-EH-MEMS offers a compact and sustainable approach for predictive maintenance in rotating machinery, reducing the reliance on external power sources and enhancing the reliability of industrial systems. Full article

Establishing an accurate high-moisture corn ear fragmentation model using the Discrete Element Method is crucial for studying the processing and fragmentation of high-moisture corn ears. This study focuses on high-moisture corn ears during the early harvest stage, developing a fragmentable corn ear model and calibrating its bonding parameters. First, based on the Hertz–Mindlin method in the Discrete Element Method, a three-layer corn cob bonding model consisting of pith, woody ring structure, and glume was established. Through a combined experimental and simulation calibration approach, the bonding parameters of the cob were determined using Plackett–Burman tests, the steepest ascent tests, and Box–Behnken tests. Subsequently, the same method was applied to establish a corn kernel bonding model, with the kernel bonding parameters calibrated through the steepest ascent and Box–Behnken tests. In order to arrange the kernel models on the cob model to achieve the construction of a complete ear model, this paper proposes a “matrix coordinate positioning method”. Through calculations, this method enables the uniform arrangement of corn kernels on the cob, thereby accomplishing the establishment of a composite model for the high-moisture corn ear. The bonding parameters between the cob and kernels were determined through compression tests. Finally, the reliability of the model was partially validated through shear testing; however, potential confounding variables remain unaccounted for in the experimental analysis. While this study establishes a theoretical framework for the design and optimization of machinery dedicated to high-moisture corn ear fragmentation processes, questions persist regarding the comprehensiveness of variable inclusion during parametric evaluation. This analytical approach exhibits characteristics analogous to incomplete system modeling, potentially limiting the generalizability of the proposed methodology. Full article

Due to the complex operating environment of combine harvesters, uneven terrain, multiple vibration sources, and complex transmission systems, failures easily occur in critical working components, especially the bolted connections of the vibrating screen. To address these issues, this study first established a bolt-tightening mechanical model. Secondly, a finite element simulation of the preload force was performed using Ansys Workbench software (2023R2). The simulation results showed that the bolt head area exhibits a ring-shaped strain distribution. To determine the critical state of bolt loosening, a single-bolt loosening test was conducted. The experimental results indicated that when the bolt pressure decreased to 78.4 N and the torque decreased to 0.5 N·m, bolt loosening intensified, and the pressure value showed a sharp decreasing trend. These pressure and torque values can be defined as the bolt loosening threshold, providing an important reference basis for subsequent monitoring and early warning. Finally, to more realistically simulate actual working conditions, a combine harvester field vibration test was conducted. By arranging triaxial acceleration sensors on the bolted connections of the vibrating screen, acceleration signals were collected under both low-speed and high-speed field operating conditions. Time–frequency analysis was performed on the signals to extract characteristic values for each measurement point. The field vibration test results showed that the characteristic values of the transmission shaft bolt structure of the vibrating screen were at a relatively high level, indicating that this part is subjected to a large vibration load. Furthermore, frequency domain feature analysis revealed that the vibration frequency components in this area are complex, which further increases the risk of bolt loosening. This study provides an in-depth analysis of the loosening characteristics and vibration characteristics of the vibrating screen’s bolted connections in combine harvesters. The results provide an important theoretical basis and technical support for the online monitoring of failures in the vibrating screen’s bolt structure. Full article

With the rapid development of urban rail transit, the floating slab vibration isolation system has become widely used in the field due to its effective vibration reduction and isolation capabilities. Traditional floating slab vibration-isolation systems mainly focus on blocking vibration transmission, neglecting energy harvesting. This paper proposes a magnetic-coupled double-wing negative stiffness energy harvester for floating slabs. A single-wing piezoelectric beam model and a finite element model of the magnetic-coupled module are established. The modal and output characteristics of the single-wing piezoelectric beam are analyzed. Furthermore, the force characteristics of the magnetically coupled negative stiffness module are analyzed. The results show that the contribution of its width to the modal frequency gradually decreases with an increase in the length of the single-wing piezoelectric beam. The thickness significantly influences the characteristic frequency, and the load is exponentially related to the output power. At the optimal load and characteristic frequency of the single-wing piezoelectric beam, the output characteristics decrease with an increase in the width. The peak value of the magnetic-coupled negative stiffness gradually decreases with an increase in the magnetic gap. The increase in remanent magnetic strength indicates that the initial state of the magnetic ring is more easily affected by external conditions. The change in axial magnetic force becomes significant with increased displacement. This research enriches the theoretical systems of piezoelectric energy harvesting technology and magnetic-coupled negative stiffness mechanism while providing important theoretical support for subsequent experimental research, optimal design, and practical applications. Full article

Arterial and venous graft spasm can occur during harvesting or immediately after coronary artery bypass grafting (CABG), leading to increased perioperative morbidity and affecting graft patency rates. Bypass grafts harvested from diabetic patients are particularly prone to spasm. This study aimed to elucidate the functional characteristics of human bypass grafts for the internal mammary artery (IMA) and saphenous vein (SV), from both diabetic and non-diabetic patients, and to determine how diabetes affected their responses to spasmogenic and relaxant agents. SV and IMA graft rings isolated from diabetic and non-diabetic patients during CABG were placed in an isolated organ bath system. Contractions to potassium chloride (10–100 mM) and phenylephrine (10⁻⁸–10⁻⁴ M) were evaluated, and relaxation responses to acetylcholine (10⁻⁹–10⁻⁴ M) and sodium nitroprusside (10⁻⁸–10⁻⁴ M) were assessed to evaluate endothelial and smooth muscle function, respectively. We observed increased responses to phenylephrine, an alpha-1 adrenoceptor agonist, in both IMAs and SVs, as well as an increased responses to potassium chloride, a non-receptor agonist, in SVs in diabetic patients compared to non-diabetic patients. We did not observe any deterioration in endothelium-dependent relaxations in either SV or IMA grafts under diabetic conditions. This study is the first to demonstrate that diabetes exacerbates potassium chloride-induced contractions in human SV grafts. Understanding the differences in potassium chloride-induced contraction profiles between arterial and venous grafts is essential in optimizing graft spasm management and improving the patency rates of bypass grafts. Full article

The genome of the mildly thermophilic hot spring purple sulfur bacterium, Allochromatium (Alc.) tepidum, contains a multigene pufBA family that encodes a series of α- and β-polypeptides, collectively forming a heterogeneous light-harvesting 1 (LH1) complex. The Alc. tepidum LH1, therefore, offers a unique model for studying an intermediate phenotype between phototrophic thermophilic and mesophilic bacteria, particularly regarding their LH1 Qy transition and moderately enhanced thermal stability. Of the 16 α-polypeptides in the Alc. tepidum LH1, six α1 bind Ca²⁺ to connect with β1- or β3-polypeptides in specific Ca²⁺-binding sites. Here, we use the purple bacterium Rhodospirillum rubrum strain H2 as a host to express Ca²⁺-bound and Ca²⁺-free Alc. tepidum LH1-only complexes composed of α- and β-polypeptides that either contain or lack the calcium-binding motif WxxDxI; purified preparations of each complex were then used to test how Ca²⁺ affects their thermostability and spectral features. The cryo-EM structures of both complexes were closed circular rings consisting of 14 αβ-polypeptides. The Q_y absorption maximum of Ca²⁺-bound LH1 (α1/β1 and α1/β3) was at 894 nm, while that of Ca²⁺-free (α2/β1) was at 888 nm, indicating that Ca²⁺ imparts a Q_y transition of 6 nm. Crucially for the ecological success of Alc. tepidum, Ca²⁺-bound LH1 complexes were more thermostable than Ca²⁺-free complexes, indicating that calcium plays at least two major roles in photosynthesis by Alc. tepidum—improving photocomplex stability and modifying its spectrum. Full article