Search Results (266)

Solar-driven irrigation, a promising clean technology for agricultural water conservation, is constrained by mismatched photovoltaic (PV) pump outflow and irrigation demand, alongside unstable PV output. While compressed-air energy storage (CAES) shows mitigation potential, existing studies lack systematic explorations of pump water-lifting characteristics and supply capacity under coupled meteorological and air pressure effects, limiting its practical promotion. This study focuses on a solar-coupled compressed-air energy storage regulated sprinkler irrigation system (CAES-SPSI). Integrating experimental and theoretical methods, it establishes dynamic flow models for three DC diaphragm pumps considering combined PV output and outlet back pressure, introduces pressure loss and drop coefficients to construct a nozzle pressure dynamic model via calibration and iteration, and conducts a 1-hectare corn field case study. The results indicate the following: pump flow increases with PV power and decreases with outlet pressure (model deviation < 9.24%); nozzle pressure in pulse spraying shows logarithmic decline; CAES-SPSI operates 10 h/d, with hourly water-lifting capacity of 0.317–1.01 m³/h and daily cumulation of 6.71 m³; and the low-intensity and long-duration mode extends irrigation time, maintaining total volume and optimal soil moisture. This study innovatively incorporates dynamic air pressure potential energy into meteorological-PV coupling analysis, providing a universal method for quantifying pump flow changes, clarifying CAES-SPSI’s water–energy coupling mechanism, and offering a design basis for its agricultural application feasibility. Full article

In view of the problems of high weed regeneration rate in traditional mechanical weeding and environmental risk in chemical weeding, a synergetic strategy of “mechanical damage + wound spraying mechanism” was proposed, and an intelligent weeding device combining synchronous cutting and spraying was designed to enhance the efficacy of herbicides and reduce their use. Focusing on the physical characteristics of weeds and the cutting mechanism, the analysis of the weed-cutting system and the force characteristics of the cutting tool were conducted. Key factors affecting cutting quality were identified, and their respective value ranges were determined. A targeted spraying system was developed, featuring a conical nozzle, DC diaphragm pump, and electromagnetic control valve. The Delta parallel manipulator, equipped with both the cutting tool and nozzle, was designed, and a kinematic model was established for both its forward and inverse movements. Genetic algorithms were applied to optimize structural parameters, aiming to ensure effective coverage of typical weed distribution areas within the working space. A simulated environment measurement was built to verify the motion accuracy of the manipulator. Field experiments demonstrated that the equipment achieved an 81.5% wound weeding rate on malignant weeds in the seedling stage at an operating speed of 0.6 m/s, with a seedling injury rate below 5%. These results validate the high efficiency of the integrated mechanical cutting and targeted spraying system, offering a reliable technical solution for green and intelligent weed control in agriculture. This study fills the blank of only focusing on recognition accuracy or weeding rate under a single weeding method, but lacks a cooperative weeding operation. Full article

Advanced alkaline water electrolysis (AWE) in “zero-gap” configuration is a promising approach for low-temperature hydrogen production, but its efficiency strongly depends on the design and surface chemistry of nickel-based electrodes. Here, we present a simple dip-and-drying method (DDM) to modify commercial nickel foam with a Ni–FeOOH/PTFE microporous catalytic layer and evaluate its electrochemical performance in 1 M KOH and in a laboratory zero-gap cell with a Zirfon^® Perl 500 UTP diaphragm, through circulating 25 wt.% KOH. The FeSO₄-assisted DDM treatment generates mixed Ni–Fe oxyhydroxide surface species, while PTFE imparts control hydrophobicity, enhancing both catalytic activity and gas-release behavior. Annealing the electrode (DDM-NF-CAT-A) results in a cell voltage of 2.45 V at 1 A·cm⁻² and 80 °C, demonstrating moderate performance comparable to other Ni-based electrodes prepared via low-complexity methods, though below that of optimized state-of-the-art zero-gap systems. Short-term durability tests (80 h at 0.5 A·cm⁻²) indicate stable operation, but long-term industrial performance was not assessed. These findings illustrate the potential of the DDM approach as a simple, low-cost route to structured nickel foam electrodes and provide a foundation for further optimization of catalyst loading, microstructure, and long-term stability for practical AWE applications. Full article

Bamboo has evolved a highly optimized structural system in its culms, which this study transfers into lightweight fiber composite trusses fabricated by coreless filament winding. Focusing on the structural segmentation involving diaphragms of the biological role model, this design principle was integrated into the additive manufacturing process using a multi-stage winding, a tiling approach, and a water-soluble winding fixture. Through a FE-assisted analytical abstraction procedure, the transition to a carbon fiber material system was considered by determining a geometrical configuration optimized for structural mass, bending deflection, and radial buckling. Samples were fabricated from CFRP and experimentally tested in four-point bending. In mass-specific terms, integrating diaphragms into wound fiber composite samples improved failure load by 36%, ultimate load by 62%, and energy absorption by a factor of 7, at a reduction of only 14% in stiffness. Benchmarking against steel and PVC demonstrated superior mass-specific performance, although mōsō bamboo still outperformed all technical solutions, except in energy absorption. Full article

This paper addresses the seismic retrofitting of masonry churches with timber roofs by designing a ductile roof diaphragm with a new energy-based methodology. The proposed approach relies on nonlinear dynamic analyses conducted on an equivalent structural model. In this model, masonry nonlinearity is represented by rotational plastic hinges at the base of the equivalent wall elements. Roof system nonlinearity is modeled by shear plastic hinges simulating the energy dissipation of steel connections. In the equivalent model, the earthquake is implemented using a set of spectrum-compatible accelerograms. The dynamic response of the aforementioned plastic hinges is analyzed in terms of equivalent damping during the seismic events by extracting the relevant hysteresis cycles. This allows for the evaluation of both dissipated and strain energy. The estimation of the equivalent damping ratio provided by the roof diaphragm is based on multiple design configurations. After identifying the maximum achievable damping ratio, the study suggests ways to determine the corresponding roof stiffness, which defines the optimal retrofit configuration. This configuration is then implemented in a three-dimensional model that includes nonlinear properties for both masonry and connection elements, allowing a validation of the seismic response obtained from the initial equivalent model with a more complex and detailed model. Finally, a seismic response comparison is conducted between the optimized dissipated energy configuration, based on damping ratio evaluation, and an overstrength design variant determined considering the elastic behavior of the roof connections. Full article

Orthotropic steel decks (OSDs) serve as critical load-bearing components in long-span steel bridges, but high-amplitude welding residual stresses (WRSs) generated during the welding process pose significant threats to structural integrity. To mitigate these stresses, post-weld heat treatment (PWHT) has emerged as a promising technique. This investigation first establishes a semi-structural thermo-elasto-plastic finite element model of the Deck-U-rib-Diaphragm system with a six-pass welding sequence. The temperature field is modeled via a double-ellipsoidal heat source and birth–death element approach. Subsequently, thermo-mechanical coupling analysis is conducted to investigate the distribution characteristics of Von Mises residual stresses. The stress relief effect of PWHT is then explored by comparing different holding temperatures (T) and holding times (t), achieving a balance between stress reduction effectiveness and economic efficiency, when T = 550 °C and t = 40 min. Finally, full-scale experimental tests are designed, and the hole-drilling method is utilized to validate the numerical simulation results. This research provides valuable insights for the design of PWHT processes for OSDs. Full article

The extensive development of urban underground space increases the risk of deformation to adjacent structures during deep excavations. This study investigates the response of three low-strength strip-foundation buildings (#4, #8, and #11 of the Ninggong Apartment) in Nanjing, China, affected by the excavation of an adjacent super-long, narrow subway station. The site is located in a typical soft alluvial area of the Yangtze River, characterized by highly compressible and sensitive soil, which poses substantial challenges. Pre-construction ground improvement was implemented to mitigate the impacts of diaphragm wall trenching; however, monitoring data indicated that buildings’ settlements of this stage still reached 28.2%, 24.8%, and 27.2% of their final values, with extensive influence zones. Subsequent excavation of the eastern and middle sections induced further cumulative and differential settlements, raising safety concerns and necessitating structural strengthening before adjacent western excavation. An integrated underpinning system, combining anchor static pressure steel pipe piles with a raft foundation, was adopted. Although short-term settlement increased during pile and raft installation, post-strengthening settlement rates decreased significantly. The adjacent western excavation caused only 13.3% of the settlement to be observed during the middle section’s excavation. All buildings were ultimately protected from excessive deformation. The protective strategies and lessons learned provide practical guidance for similar projects. Full article

Air-coupled ultrasonic detection demands high transmission performance from piezoelectric micromachined ultrasonic transducers (PMUTs). However, existing microelectromechanical system (MEMS)-based PMUTs deliver limited output, which compromises measurement accuracy and constrains further development. This work proposes a novel PMUT design with a cantilevered, boundary-suspended diaphragm that relieves residual stress, relaxes edge constraints, increases the mechanical degrees of freedom, and enables larger vibration amplitudes. Additionally, this work develops an accurate air-coupling model to predict device performance and a streamlined micro-nanofabrication process for device realization. Experimental results show that under a 1 Vpp (−5 Voffset) drive, the device achieves a peak acoustic pressure of 4.004 Pa at 69.3 kHz, measured at 10 cm distance in air, corresponding to a maximum sound pressure level of 106.02 dB (re 2 × 10⁻⁵ Pa). Compared to a traditional PMUT at 98.45 dB, this represents a 7.57 dB improvement and, to our knowledge, the highest reported sound pressure level at 10 cm for a single PMUT operating near 70 kHz under a 1 Vpp excitation. These results validate the significant enhancement in transmission performance achieved by the proposed topological structure, offering a solution to overcome the common bottleneck of insufficient output in PMUTs, and indicate strong potential for broader air-coupled sensing applications. Full article

Skeletal muscle dysfunction is a major systemic manifestation of COPD that shapes symptoms, exercise tolerance and mortality. Current evidence can be integrated within a Damage–Regeneration–Remodeling framework linking mechanics and biology to clinical phenotypes. Pulmonary hyperinflation and chest wall geometry chronically load the diaphragm and other respiratory muscles in COPD, whereas inactivity and exacerbation-related disuse underload locomotor muscles. Across muscle compartments, oxidative/nitrosative stress, activation of proteolytic pathways, mitochondrial and endoplasmic reticulum stress, microvascular limitations, neuromuscular junction instability, and myosteatosis degrade muscle quality. The diaphragm adapts with a fast-to-slow fiber shift, greater oxidative capacity, and sarcomere foreshortening, improving endurance, whereas limb muscles show atrophy, a glycolytic shift, reduced oxidative enzymes, extracellular matrix accrual, and fat infiltration. Translational levers that address these mechanisms include: (I) Reduce damage: bronchodilation, lung-volume reduction, oxygen, non-invasive ventilation, early mobilization, pulmonary rehabilitation, neuromuscular stimulation, and corticosteroid stewardship; (II) Enable regeneration: progressive resistance plus high-intensity/heavy-load endurance training; adequate protein and vitamin-D intake, and endocrine correction; and (III) Steer remodeling: increase physical activity (with/without coaching/telecoaching), functional assessment and CT or MRI monitoring, inspiratory-muscle training, and phenotype-guided adjuncts in selected cases. This framework clarifies why lung deflation strategies benefit inspiratory mechanics, whereas limb recovery requires behavioral and metabolic interventions layered onto systemic optimization. Full article

The hydrogen energy industry is rapidly developing, positioning hydrogen refueling stations (HRSs) as critical infrastructure for hydrogen fuel cell vehicles. Within these stations, hydrogen compressors serve as the core equipment, whose performance and reliability directly determine the overall system’s economy and safety. This article systematically reviews the working principles, structural features, and application status of mechanical hydrogen compressors with a focus on three prominent types based on reciprocating motion principles: the diaphragm compressor, the hydraulically driven piston compressor, and the ionic liquid compressor. The study provides a detailed analysis of performance bottlenecks, material challenges, thermal management issues, and volumetric efficiency loss mechanisms for each compressor type. Furthermore, it summarizes recent technical optimizations and innovations. Finally, the paper identifies current research gaps, particularly in reliability, hydrogen embrittlement, and intelligent control under high-temperature and high-pressure conditions. It also proposes future technology development pathways and standardization recommendations, aiming to serve as a reference for further R&D and the industrialization of hydrogen compression technology. Full article

The dynamic loads affecting earth-retaining structures may increase in seismically active regions. Therefore, studying the soil–structure interaction among the soil, shoring systems, and adjacent structures is crucial. However, there is limited research on this important topic. This study investigates the seismic performance of a deep braced excavation and a nearby 10-story building in sandy soil formation. The main focus of this study is the consideration of the influence of varying foundation depths of adjacent structures on the seismic response of the shoring system and the performance of the shoring system and adjacent structure under different earthquake records. PLAXIS 2D software (Version 22.02) was used to carry out the numerical analysis. Sandy soil was modeled using the Hardening Soil with small-strain stiffness model (HS-small). Back analysis of observation data extracted from a real case study of a deep braced excavation in the central district of Kaohsiung City, adjacent to the O₇ Station on the Orange Line of the Kaohsiung MRT system in Taiwan, was used to validate the numerical analysis. Beyond model validation, a parametric study was conducted to address the effect of the foundation level of the building adjacent to the excavation on both the seismic behavior of the shoring system and the structure itself, using the Loma-Prieta (1989) earthquake record. The parametric study was further extended to assess the responses of the shoring system and the adjacent structure under the influence of the earthquake records of Loma-Prieta (1989), Northridge (1994), and El-Centro (1940). The results show that the maximum lateral displacement of the diaphragm wall occurred at the top of the wall in all studied cases. The maximum dynamic bending moment in the retaining structure was more than three times the static one on average. In contrast, the dynamic shear force was more than 2.85 times the static one on average. In addition, the dynamic axial force of the first and second struts was 1.38 and 3.17 times the static forces, respectively. The results also reveal large differences in the behavior of the shoring system and the adjacent structure between the different earthquake records. Full article

Prior research has proposed a basic configuration for a deep-sea mining system integrating slurry transport and wastewater discharge, and examined the operational characteristics of water-driven diaphragm pumps. Against the backdrop of commercial deep-sea polymetallic nodule exploitation, this study focuses on the technical design of seabed diaphragm pump groups and hydraulic parameter matching for a coupled slurry transport-wastewater discharge system. The solid–liquid two-phase output characteristics of the water-driven diaphragm pump were analyzed, leading to the proposal of a four-pump staggered configuration to ensure continuous particulate discharge throughout the full operating cycle. To meet commercial mining capacity requirements, the system consists of two sets (each with four pumps) operating with a phase offset to reduce fluctuations in slurry output concentration. A centralized output device was developed for the pump group, and a centralized mixing tank was designed based on analyses of outlet pipe length and positional effects. CFD-DEM simulations show that the combined effects of phased pump operation and centralized mixing tank mixing result in the slurry concentration delivered to the riser pipeline staying within ±1% of the mean for up to 57.8% of the system’s operational time. Considering the characteristics of both diaphragm and centrifugal pumps, the system is designed to output high-concentration slurry from the seabed diaphragm pumps, driven solely by wastewater, while centrifugal pumps provide lower-concentration transport by adding supplementary water from a buffer—thus reducing the risk of clogging. Under the constraints of centrifugal pump capacity, the system’s hydraulic parameters were optimized to maximize overall slurry transport efficiency while minimizing the energy consumption from wastewater discharge. The resulting configuration defines the flow rate and slurry concentration of the diaphragm pump group. Compared with conventional centrifugal pump-based transport schemes, the proposed system increases the slurry pipeline efficiency from 53.14% to 55.43% and reduces wastewater discharge-related pipeline resistance losses from 475.9 mH₂O to 361.7 mH₂O. Full article

During blast shock wave pressure measurement, strong mechanical vibrations and shocks can affect the dynamic characteristics of shock wave pressure sensors, introducing measurement errors. To improve measurement accuracy for the compression phase, a specialized buffer device was designed to enhance the sensor’s dynamic response to transient pressure rises. Using a double-diaphragm shock tube, the dynamic calibration of the enhanced sensor system was carried out and the influence of the buffer device on the dynamic performance was investigated. A mathematical model based on a backpropagation (BP) neural network was developed to characterize the sensor system, and a dynamic compensation method was implemented to improve the enhanced shock wave pressure sensor system. Experimental results demonstrated that while the buffer device significantly reduced the operational bandwidth of the sensor system, the BP neural network-based dynamic compensation effectively widened the bandwidth and improved measurement accuracy. This research provides a practical solution for high-precision dynamic pressure measurement, specifically targeting the compression phase in complex environments. Full article

Chronic obstructive pulmonary disease (COPD) and chronic heart failure (CHF) are pathologies that impact mortality and morbidity worldwide. These chronic diseases have multiple causes, and they share some common clinical symptoms, such as diaphragm dysfunction (DD) and cognitive decline (CD), which, in turn, increase the mortality and morbidity rates in patients with COPD and CHF. One of the causes of CD is impaired glymphatic system function, with an accumulation of proteins and metabolites in the central nervous system. The glymphatic system is a structure that has not yet been widely considered by researchers and clinicians. Three key factors stimulate the ongoing physiological function of the glymphatic system: autonomic balance, heart rate, and, most importantly, the diaphragm. All these factors are altered in patients with COPD and CHF. This article reviews the relationship between the importance of the diaphragm, the glymphatic system, and CD, focusing on inspiratory rehabilitation training (IMT). Based on the data reported in this narrative review, we can strongly speculate that a consistent regimen of IMT in patients can improve cognitive status, reducing the cascade of symptoms that follow the diagnosis of CD. Further research is needed to understand whether targeting the glymphatic system with IMT is an effective option for helping patients delay the onset of CD. Full article

Wavefront aberrations caused by thermal flows or arising from the quality of optical components can significantly impair wireless communication links. Such aberrations may result in an increased error rate in the received signal, leading to data loss in laser communication applications. In this study, we explored a newly developed combined stochastic gradient descent optimization algorithm aimed at compensating for optical distortions. The algorithm we developed exhibits linear time and space complexity and demonstrates low sensitivity to variations in input parameters. Furthermore, its implementation is relatively straightforward and does not necessitate an in-depth understanding of the underlying system, in contrast to the Stochastic Parallel Gradient Descent (SPGD) method. In addition, a developed switch-mode approach allows us to use a stochastic component of the algorithm as a rapid, rough-tuning mechanism, while the gradient descent component is used as a slower, more precise fine-tuning method. This dual-mode operation proves particularly advantageous in scenarios where there are no rapid dynamic wavefront distortions. The results demonstrated that the proposed algorithm significantly enhanced the total collected power of the beam passing through the 10 μm diaphragm that simulated a 10 μm fiber core, increasing it from 0.33 mW to 2.3 mW. Furthermore, the residual root mean square (RMS) aberration was reduced from 0.63 μm to 0.12 μm, which suggests a potential improvement in coupling efficiency from 0.1 to 0.6. Full article