Search Results (513)

The integration of a real-time image processing system using multiple webcams with a variable rate spraying system mounted on the back of an unmanned tractor presents an effective solution to the labor shortage in agriculture. This research aims to design and fabricate a low-cost, variable-rate, remote-controlled sprayer specifically for use in sugarcane fields. The primary method involves the modification of a 15-horsepower tractor, which will be equipped with a remote-control system to manage both the driving and steering functions. A foldable remote-controlled spraying arm is installed at the rear of the unmanned tractor. The system operates by using a webcam mounted on the spraying arm to capture high-angle images above the sugarcane canopy. These images are recorded and processed, and the data is relayed to the spraying control system. As a result, chemicals can be sprayed on the sugarcane accurately and efficiently based on the insights gained from image processing. Tests were conducted at various nozzle heights of 0.25 m, 0.5 m, and 0.75 m. The average system efficiency was found to be 85.30% at a pressure of 1 bar, with a chemical spraying rate of 36 L per hour and a working capacity of 0.975 hectares per hour. The energy consumption recorded was 0.161 kWh, while fuel consumption was measured at 6.807 L per hour. In conclusion, the development of the remote-controlled variable rate sprayer mounted on an unmanned tractor enables immediate and precise chemical application through remote control. This results in high-precision spraying and uniform distribution, ultimately leading to cost savings, particularly by allowing for adjustments in nozzle height from a minimum of 0.25 m to a maximum of 0.75 m from the target. Full article

The constitutive model is widely employed to characterize the rheological properties of metallic materials under high-temperature conditions. It is typically derived from a series of high-temperature tests conducted at varying deformation temperatures, strain rates, and strains, including hot stretching, hot compression, separated Hopkinson pressure bar testing, and hot torsion. The original experimental data used for establishing the constitutive model serves as the foundation for developing phenomenological models such as Arrhenius and Johnson–Cook models, as well as physical-based models like Zerilli–Armstrong or machine learning-based constitutive models. The resulting constitutive equations are integrated into finite element analysis software such as Abaqus, Ansys, and Deform to create custom programs that predict the distributions of stress, strain rate, and temperature in materials during processes such as cutting, stamping, forging, and others. By adhering to these methodologies, we can optimize parameters related to metal processing technology; this helps to prevent forming defects while minimizing the waste of consumables and reducing costs. This study provides a comprehensive overview of commonly utilized experimental equipment and methods for developing constitutive models. It discusses various types of constitutive models along with their modifications and applications. Additionally, it reviews recent research advancements in this field while anticipating future trends concerning the development of constitutive models for high-temperature deformation processes involving metallic materials. Full article

The optimization of ventilation strategies in high-ceiling theater stage spaces is crucial for improving thermal comfort and energy efficiency. This study addresses the challenge of uneven temperature distribution and airflow stagnation in stage environments by employing computational fluid dynamics (CFD) simulations to evaluate the effectiveness of different ventilation modes, including natural, mechanical, and hybrid systems. Six airflow organization scenarios were designed based on modifications to structural layout, equipment settings, and mechanical disturbances (e.g., fan integration). Key evaluation indicators such as temperature uniformity coefficient, airflow velocity, and exhaust efficiency were used to assess performance. The results show that a multi-dimensional optimization approach combining spatial adjustments and mechanical disturbances significantly reduced the average temperature from 26 °C to 23 °C and the temperature uniformity coefficient from 2.79 to 1.49. This study contributes a comprehensive design strategy for stage ventilation that improves comfort while minimizing energy consumption, offering practical implications for performance space design and HVAC system integration. Full article

As the global demand for electronic equipment continues to grow, many devices are being replaced more frequently, resulting in a rapid rise in electronic waste (e-waste), now the fastest growing waste stream worldwide. Motivated by this, the objective of this study is to present an environmentally friendly method to recycle acrylonitrile–butadiene–styrene (ABS), one of the most common e-waste plastics, by using it for asphalt production. In contrast to earlier methods of plastic-modified asphalt production involving complex pretreatments or complimentary additives unsuitable for plant-scale use, this study aims to demonstrate a practical, low-cost solution through the use of carbon black. This approach included physically pretreating ABS plastics for size reduction and incorporating waste tire-derived carbon black to promote effective dispersion in asphalt during wet modification. The rheological properties of the e-waste-modified asphalt were subsequently assessed. The test results indicated that recycling ABS plastics with a blending content of 5% alongside 5% carbon black can enhance cold-weather cracking resistance and high-temperature anti-rutting performance of asphalt. The enhancement can be attributed to the proper preparation procedures of ABS plastics and the addition of carbon black, which can further improve the performance by promoting the proper dispersion of plastic particles in asphalt. The outcome of this study indicates that recycling e-waste plastics through asphalt production can lead to more green and sustainable asphalt construction, reduce total construction costs, and most importantly enhance performance. Full article

In recent years, the number of vehicles in cities has visibly increased, leading to continuous modifications in general mobility. Pollution levels and congestion cases are reaching higher numbers as well, pointing to a need for better optimization solutions. Several existing control systems still rely on fixed timings for traffic lights, lacking an adaptive approach that can adjust the timers depending on real-time conditions. This study aims to provide a design for such a tool, by implementing two different approaches: Fuzzy Logic Optimization and an Adaptive Traffic Management strategy. The first controller involves Fuzzy Logic based on rule-based that adjust green and red-light timings depending on the number of vehicles at an intersection. The second model provides traffic adjustments based on external equipment such as road sensors and cameras, offering dynamic solutions tailored to current traffic conditions. Both methods are tested in a simulated environment using SUMO (Simulation of Urban Mobility). They were evaluated according to key efficiency indicators, namely average waiting time, lost time per cycle, number of stops per intersection, and overall traffic fluidity. Results demonstrate that Q-learning maintains consistent waiting times between 2.57 and 3.71 s across all traffic densities while achieving Traffic Flow Index values above 85%, significantly outperforming Fuzzy Logic, which shows greater variability and lower efficiency under high-density conditions. Full article

In this study, a self-propelled hard hose traveler is developed as a modification of the conventional design. The traveler demonstrated enhanced field applicability and intelligence level in Europe and central–eastern China. A parametric configuration scheme was attained through the irrigator’s computational modeling and experimental validation. This study proposed a uniform water distribution calculation model for single-sprinkler linear-move irrigation. The deviation rate between calculated and experimental values was 7.3%. The average application depth decreased with increased sprinkler motion speed and path spacing. The uniformity of water distribution (CU value) exhibited an oscillating trend as the path spacing changed. As the sprinkler rotation angle increased along a specific path, the CU value first rose from 69.2% to 80.0% and then declined to 68.7%. When irrigation and sprinkler motions were combined, the CU value at 1.5 R initially decreased from 92.1% to 72.9%, then increased to 84.2% as the sprinkler rotation angle increased. The combined sprinkler and irrigation motions showed a significantly better uniformity than the specific path irrigation. The highest CU value was 95.0%, with a nozzle diameter of 16.0 × 6.0 mm, a sprinkler rotation angle of 180°, and a path spacing of 1.6 R. This study introduces a novel approach for water-saving irrigation equipment and offers practical guidance for farmers on operating the self-propelled hard hose traveler. Full article

This study synthesized two eco-friendly inhibitors—a chitosan–copper metal–organic framework (CS@Cu MOF) and chitosan–Schiff base–Cu complex (Schiff–CS@Cu)—for Q345 steel protection in 3.5% NaCl/1M HCl. Electrochemical and weight loss analyses demonstrated exceptional corrosion inhibition: untreated specimens showed a 25.889 g/(m²·h) corrosion rate, while 100 mg/L of CS@Cu MOF and Schiff–CS@Cu reduced rates to 2.50 g/(m²·h) (90.34% efficiency) and 1.67 g/(m²·h) (93.56%), respectively. Schiff–CS@Cu’s superiority stemmed from its pyridine–Cu²⁺ chelation forming a dense coordination barrier that impeded Cl⁻/H⁺ penetration, whereas CS@Cu MOF relied on physical adsorption and micro-galvanic interactions. Surface characterization revealed that Schiff–CS@Cu suppressed pitting nucleation through chemical coordination, contrasting with CS@Cu MOF’s porous film delaying uniform corrosion. Both inhibitors achieved optimal performance at 100 mg/L concentration. This work establishes a molecular design strategy for green inhibitors, combining metal–organic coordination chemistry with biopolymer modification, offering practical solutions for marine infrastructure and acid-processing equipment protection. Full article

As a natural polymerized material, Chinese lacquer has numerous applications, although its processing is associated with volatile organic compounds (VOCs), which will cause a health risk. This paper was mainly focused on the detection of volatiles in the Chinese lacquer and its possible allergy mechanisms based on the properties of the lacquer, such as the main components, chemical properties, and allergy mechanisms of the unit phenols, aldehydes, and ketones and terpenes in the volatiles. Based on the detection technology (such as GC/MS) and allergy mechanism, a variety of prevention and control strategies are proposed, including the use of cyclodextrin–chitosan embedding technology to reduce the antigenicity of lacquer phenols and the directional modification of the active site of laccase to inhibit the generation of quinone toxicity products, as well as the research and development of antioxidant protective equipment for different volatiles, the installation of ventilation and purification devices, and the addition of antioxidants. They are all aimed at providing scientific evidence and practical guidance for the safe use of lacquer, the health protection of the practitioners, and the sustainable development of the related industries. Full article

Background: Food and nutrition security are key social determinants of cardiometabolic health. While food security reflects access to sufficient food, nutrition security incorporates the quality, consistency, and usability of food that supports long-term health. However, few studies have examined how household-level barriers to food utilization shape these relationships. Objective: This study assessed whether tangible (e.g., equipment, storage) and intangible (e.g., time, knowledge) food utilization barriers modify the associations between food and nutrition security and cardiometabolic outcomes in low-income adults. Methods: A cross-sectional survey was conducted among 486 low-income adults across five U.S. states. Participants reported household food security (USDA 18-item module), nutrition security (four-item scale), and utilization barriers (eight-item scale, categorized into tangible and intangible subscales). Self-reported diagnoses of hypertension, hyperlipidemia, and diabetes were combined into a cardiometabolic outcome. Mixed-effects logistic regression models, adjusted for sociodemographic and program participation factors, were used to assess associations and effect modification. Results: Higher nutrition security was associated with lower odds of cardiometabolic conditions (AOR = 0.59; 95% CI: 0.41–0.83). Tangible barriers significantly modified the relationship between nutrition security and hypertension (p-interaction = 0.04), with stronger protective effects observed in households without such barriers. No significant moderation effects were found for intangible barriers or for food security. Conclusions: Tangible household barriers influence the protective association between nutrition security and cardiometabolic outcomes. Public health strategies should address not only food access but also the practical resources required to store, prepare, and consume healthy foods effectively. Full article

Compressed air energy storage (CAES) systems represent a critical technological solution for addressing power grid load fluctuations by generating electrical power during peak load periods and storing energy during low load periods. As a prominent branch of CAES, isothermal compressed air energy storage (ICAES) systems have attracted significant research attention due to their elimination of requirements for high-temperature storage chambers and high-temperature compressors. Implementing constant-pressure operation in air storage reservoirs not only enhances energy storage density but also improves system safety. However, existing constant-pressure air storage methodologies necessitate supplementary infrastructure, such as high-pressure water reservoirs or elevated hydraulic columns, thereby escalating capital expenditures. This study introduces a novel constant-pressure air storage strategy for ICAES systems utilizing a linear-driven liquid piston mechanism. The proposed approach achieves constant-pressure air storage through the dual-mode operation strategies of buffer tanks (CBA and CBP modes) and hydraulic cylinders (CPP and CPW modes), eliminating the requirement for an auxiliary high-pressure apparatus or extensive civil engineering modifications. A prototype two-stage constant-pressure ICAES architecture was proposed, integrating low-pressure equipment with liquid pistons and providing detailed operational processes for preconditioning, energy storage, and power generation. A comprehensive mathematical model of the system is developed and validated through process simulation and performance characterization of a 100 kWh capacity system. It demonstrates that under operational conditions of 1 MPa of low pressure and 5 MPa of storage pressure, the system achieves an efficiency of 74.0% when the low-pressure equipment and liquid piston exhibit efficiencies of 85% and 90%, respectively. Furthermore, parametric analysis reveals a negative correlation between system efficiency and low-pressure parameters. Full article

With the advancement in power electronics technology, variable-frequency drives have been widely adopted for motor operation due to their inherent benefits: control performance, extending equipment life, and energy savings. The most used technique is Sine Pulse Width Modulation, as it solely requires the modification of the reference signal (sine wave). However, Space Vector Pulse Width Modulation offers lower total harmonic distortion. Therefore, this study presents a technique for the control of induction motors operating in open-loop mode, utilizing a two-level voltage source inverter with a frequency range of 31 to 300 Hz. The proposed control system is modified to encompass between 930 and 1848 switching periods, varying the number of switching periods along with the frequency variation. This approach allows the use of a single LCL filter across the whole frequency spectrum. It is adapted for implementation in an 8-bit microcontroller, which has its inherent limitations, yet it achieves performance levels similar to those found in high-level processors like FPGAs and DSPs. The signals generated by the microcontroller are captured by a DAQ card and input into a MATLAB/Simulink model to observe and analyze the performance of the proposed control system. Full article

In this study, a strategy was adopted to promote the formation of NiAl precipitates with the aim of enhancing strength by incorporating a 0.2 wt.% Al into a traditional ultra-low carbon bainitic (ULCB) steel alloy. By integrating thermo-mechanical control processing (TMCP) and a tailored tempering process, a new-generation steel with an outstanding combination of properties has been successfully developed for shipbuilding and marine engineering equipment. It features a yield strength of 880 MPa, a yield ratio of 0.84, and an impact toughness of 175 J. The precipitation characteristics of nanoscale particles in this steel, including NiAl intermetallics and carbides, were systematically investigated. The results show that the alloy with low Al addition formed NiAl precipitates during tempering. The high-density distributions of NiAl, (Mo, V)C, and (Ti, V, Nb)C precipitates, which exhibit slow coarsening kinetics, played a dominant role in enhancing the strength of the tempered steel. In addition to precipitation, the microstructure before and after tempering was also analyzed. It was observed that a granular bainite morphology was favorable for decreasing the yield ratio. Additionally, the formation of reverse-transformed austenite during tempering was critical for retaining toughness despite substantial strength gains. Finally, theoretical modeling was employed to quantitatively assess the contributions of these microstructural modifications to yield strength enhancement of thermo-mechanical controlled processing (TMCP) and tempered steel. This study establishes a fundamental basis for subsequent industrial-scale development and practical engineering applications of novel products. Full article

This paper is focused on the modification of polyurethane coating applied to the outer layer of hybrid textile materials dedicated to personal protective equipment. For this purpose, graphene with various weight fractions, i.e., 0.25 and 0.5 wt.%, was introduced into the polyurethane matrix. The prepared pastes were applied to meta-aramid fabric as coating. The results of the thermogravimetric analysis of polymer coating showed a shift in the onset temperature of the polymer coating to higher values after graphene addition, which indicates an improvement in thermal stability. Considering mechanical properties, the implementation of the coating on meta-aramid fabric reduces tear resistance but this may be improved by the addition of 0.5 wt.% of graphene. Such a hybrid textile material meets the tearing force requirements for protective clothing for firefighters according to EN 469:2020. Full article

This study aimed to evaluate the characteristics of short acquisition times using the Clear adaptive Low-noise Method (CaLM) and Advanced intelligent clear-IQ engine (AiCE) reconstructions in a semiconductor-based positron emission tomography (PET)/computed tomography system. PET data were acquired for 30 min in list mode and resampled into time frames ranging from 15 to 120 s. Images were reconstructed using three-dimensional ordinary Poisson ordered-subset expectation maximization (OSEM) with time of flight (TOF) and OSEM with TOF and point spread function modeling (PSF) algorithms, with OSEM iterations adjusted from 1 to 20 and CaLM applied under Mild, Standard, and Strong settings. AiCE reconstruction allows for the modification of only the acquisition time. The images were evaluated based on the coefficient of variation, recovery coefficient, % background variability (N_10mm), % contrast-to-% background variability ratio (Q_H10mm/N_10mm), and contrast-to-noise ratio. While OSEM with TOF reconstruction did not significantly reduce the acquisition time, the addition of PSF correction suggested the potential for further reduction. Given that the AiCE characteristics may vary depending on the equipment used, further investigation is required. Full article

Lithium-ion batteries (LIBs) are widely used as energy storage units in electric vehicles, mobile phones, and other electric devices due to their high voltage, large capacity, and long cycle life. Lithium-ion batteries are prone to thermal runway (TR), resulting in fires and explosions, which can seriously hinder the commercial development of LIBs. A series of safety methods has been studied to prevent TR of LIBs. The safety methods for suppressing TR in LIBs were reviewed, including safety equipment method, material modification method, thermal management method, and cooling method. The mechanism, advantages and disadvantages, and future applications of the TR suppression method are discussed. The effectiveness of the proposed safety method was evaluated through technical analysis and experimental testing, and the inhibitory effects of different safety methods on battery TR were summarized. The future trend of suppressing TR is discussed by summarizing and generalizing existing technologies for suppressing thermal runaway. This study provides a reference for exploring more effective methods to mitigate TR in the future. Full article