Search Results (8,501)

Chaetognaths play an essential role in zooplankton communities and significantly contribute to their overall biomass. Changes in the hydrographic properties of the water column, driven by hydrodynamic processes, affect their species richness and abundance. This study investigates the species richness and abundance of chaetognaths, as well as their relationship with circulation patterns at the boundary of the Pacific Ocean and the Gulf of California, Mexico. The analysis is based on high-resolution hydrographic data and zooplankton samples collected during the early summer of 2019. The results revealed a cyclonic circulation pattern that impacted the chaetognath community at depths greater than 200 m. This pattern resulted in higher chaetognath densities along the peninsular coast compared to the mainland coast. A total of 15 species from three different families were identified. Among these, Flaccisagitta enflata had the highest density, recorded at 16,143 ind 100 m⁻³, while Aidanosagitta neglecta exhibited a significantly lower density of only 48 ind 100 m⁻³. Multivariate statistical analyses indicated that hydrographic variables were key factors influencing the distribution of the chaetognath community during the sampling period. Given the significant research gap regarding this group in the region, our findings contribute to a deeper understanding of chaetognath communities and their relationship with circulation patterns in the Southern Gulf of California, recognized as an oasis of marine life. Full article

Promoting breakthrough innovation is a critical strategy for overcoming technological bottlenecks and addressing “chokepoint” challenges, especially for emerging economies. This paper constructs a two-tier innovation network comprising collaborative R&D and technology transaction subnetworks. Using panel data from Chinese A-share listed companies between 2008 and 2022, we empirically examine the impact of network embeddedness on firm breakthrough innovation in the artificial intelligence industry and explore the moderating effect of enterprise digitalization. The results reveal a U-shaped relationship between embeddedness breadth and breakthrough innovation, and an inverted U-shaped relationship between embeddedness depth and breakthrough innovation. The heterogeneous resource acquisition mediates these nonlinear relationships. As a firm’s digitalization intensity increases, the U-shaped and inverted U-shaped relationships between embeddedness dimensions and breakthrough innovation are significantly amplified. This study deepens our understanding of the mechanisms and boundary conditions by which network embeddedness affects firm innovation and provides new theoretical insights for fostering breakthrough innovation in emerging economies. Full article

A vast number of boreholes in underground mining operations are often plagued by deviation issues, which severely impact both production efficiency and safety. The accurate and rapid acquisition of borehole trajectories is fundamental for subsequent deviation control and correction. However, existing inclinometers are limited by their operational efficiency and estimation accuracy, making them inadequate for large-scale measurement demands. To address this, this paper proposes a novel method for the rapid and accurate reconstruction of underground mine borehole trajectories using a robotic system. We employ a custom-designed robot equipped with an Inertial Measurement Unit (IMU) and a displacement sensor, which travels stably while collecting real-time attitude and depth information. Algorithmically, a complementary filter is used to fuse data from the gyroscope with that from the accelerometer and magnetometer, overcoming both integration drift and environmental disturbances. A cubic spline interpolation algorithm is then utilized to time-register the low-sampling-rate displacement data with the high-frequency attitude data, creating a time-synchronized sequence of ‘attitude–displacement increment’ pairs. Finally, the 3D borehole trajectory is accurately reconstructed by mapping the attitude quaternions to direction vectors and recursively accumulating the displacement increments. Comparative experiments demonstrate that the proposed method significantly improves efficiency. On a complex trajectory, the maximum and mean errors were reduced to 0.38 m and 0.18 m, respectively. This level of accuracy is far superior to that of the conventional static point-by-point measurement mode and effectively suppresses the accumulation of dynamic errors. This work provides a new solution for routine borehole trajectory surveying in mining operations. Full article

To investigate the flow-field characteristics of a submerged pre-mixed abrasive water jet impinging on a wall, a physical model of the conical–cylindrical nozzle and computation domain of a submerged pre-mixed abrasive-water-jet flow field were established. Based on the software of FLUENT 2022R2, numerical simulation of the solid–liquid two-phase flow characteristics of the submerged pre-mixed abrasive water jet impinging on a wall was conducted using the DPM particle trajectory model and the realizable $k–\epsilon$ turbulence model. The simulation results indicate that a “water cushion layer” forms when the submerged pre-mixed abrasive water jet impinges on a wall. Tilting the nozzle appropriately facilitates the rapid dispersion of water and abrasive particles, which is beneficial for cutting. The axial-jet velocity increases rapidly in the convergent section of the nozzle, continues to accelerate over a certain distance after entering the cylindrical section, reaches its maximum value inside the nozzle, and then decelerates to a steady value before exiting the nozzle. In addition, the standoff distance has minimal impact on the flow-field characteristic inside the nozzle. When impinging on a wall surface, rapid decay of axial-jet velocity generates significant stagnation pressure. The stagnation pressure decreases with increasing standoff distance for different standoff-distance models. Considering the effects of standoff distance on jet velocity and abrasive particle dynamics, a standoff distance of 5 mm is determined to be optimal for submerged pre-mixed abrasive-water-jet pipe-cutting operations. When the submergence depth is less than 100 m, its effect on the flow-field characteristics of a submerged pre-mixed abrasive water jet impinging on a wall surface remains minimal. For underwater oil pipelines operating at depths not exceeding 100 m, the influence of submergence depth can be disregarded during cutting operations. Full article

Aluminum, one of the most abundant metals found on our planet, plays a crucial role in manufacturing as it is lightweight and resistant to corrosion and has excellent machinability. Of its numerous alloys, Al6061 is one of the most popular alloys used for CNC machining due to its superior mechanical and processing properties. This paper aims to investigate the impact of machining under dry and wet machining conditions. Correspondingly, the impact of dry machining on the material removal rate (MRR) and surface roughness (Ra) of Al6061 was evaluated. Machining was performed on a CNC Lathe. Two rods of Al6061 were used, and a dynamometer was attached to them to measure the radial, thrust, and tangential forces. In wet machining, the coolant used was a mixture of cutting oil and water. Different RPMs, feed rates, and depths of cut were entered into the machine as parameters. And the optimum parameters where found. This research utilizes particle swarm optimization approaches in order to evaluate optimal parameters, in contrast to traditional measurement methods such as contact profilometry or cutting force measurement. The results indicate that surface roughness rises with the depth of cut and feed rate. Ra rises by about 200% when dry machining is conducted at 0.05 mm/rev with increased depths of cut from 0.5 mm to 2.5 mm. In wet machining, the rise is much smaller, approximately 67% at 0.05 mm/rev and 30% at 0.25 mm/rev. Wet machining always produces more finished surfaces, decreasing Ra by 22–25% over dry machining. Wet machining is therefore better suited for achieving high-quality surface finish in Al6061 machining. Full article

The utilization of proper fermentation techniques is a widely recognized, efficacious approach in animal husbandry for enhancing the feed quality. However, research on vegetable waste, particularly that of roots, stems, leaves, fruits, and peels, has been rarely reported. To this end, the present study was carried out to examine the impact of vegetable leaf fermentation on growth performance, immune function, antioxidant levels, intestinal morphology, and microbial composition in sheep. Fifty-four male sheep (Oula) with an average age of 6 months and an average body weight of (21.53 ± 2.03) kg were randomly divided into three treatment groups, with six replicates each. The groups were fed with a basal diet (CON), 30% commercial fermented concentrate (CFC), and 30% vegetable leaf fermented concentrate (VFC). The results showed that compared to the CON group, both the commercial fermented concentrate and the vegetable leaf fermented concentrate improved the final weight (8.93%), average daily gain (30.67%), and dry matter intake of the sheep (1.62%). VFC increased the serum T-AOC (34.45%) and significantly increased the activities of serum and liver GSH-PX (10.95%). Meanwhile, the addition of vegetable leaf fermented concentrate increased the levels of serum IgA (63.21%), IgG (73.06%), and IgM (69.41%). VFC increased the villus height of the jejunum by 87.4% and the ileum by 185.5% and improved the villus height/crypt depth (V/C) ratio of the duodenum and ileum. CFC can also increase the villus height of the duodenum and jejunum, but has no effect on the morphology of the ileum. In addition to its other regulatory effects, VFC can further improve the richness and diversity of the rumen microbial community in sheep, with a notable enhancement in the relative abundance of key phyla, including Bacteroidetes, Ascomycota, Zygomycota, Chytridiomycota, and Basidiomycota. At the same time, the relative abundance of Succinivibrio was reduced. It can thus be concluded that the vegetable leaf fermented concentrate improves the growth performance and intestinal health of sheep. Full article

Precise localization of the fruit stem picking point is crucial for robots to achieve efficient harvesting operations. However, in unstructured orchard environments, citrus fruit stems are easily obscured by branches and leaves and affected by factors such as overlapping fruits. This leads to poor picking localization accuracy for robots, impacting their autonomous picking efficiency. Therefore, this paper proposes a method for estimating the posture of citrus fruit stems and performing picking operations under environmental occlusion, based on the YOLO-OBB algorithm. First, the YOLOv5s algorithm detects the ROI of citrus, combined with depth information to obtain their 3D point clouds. Second, the OBB algorithm constructs oriented point cloud bounding boxes to determine stem orientation and picking point locations. Finally, through hand–eye pose transformation of the robotic arm, the end-effector is controlled to achieve precise picking operations. Experimental results indicate that the average picking success rate of the YOLO-OBB algorithm reaches 82%, representing a 50% improvement over approaches without fruit stem estimation. This conclusively shows that the proposed algorithm provides precise fruit stem pose estimation, effectively enhancing robotic picking success rates under constrained fruit stem detection conditions. It offers crucial technical support for autonomous robotic harvesting operations. Full article

Poor air quality can harm human health and the environment. Air quality data are needed to understand and reduce exposure to air pollution. Air sensor data can supplement national air monitoring data, allowing for a better understanding of localized air quality and trends. However, these sensors can have limitations, biases, and inaccuracies that must first be controlled to generate data of adequate quality, and analyzing sensor data often requires extensive data analysis. To address these issues, an R-Shiny application has been developed to assist air quality professionals in (1) understanding air sensor data quality through comparison with nearby ambient air reference monitors, (2) applying basic quality assurance and quality control, and (3) understanding local air quality conditions. This tool provides agencies with the ability to more quickly analyze and utilize air sensor data for a variety of purposes while increasing the reproducibility of analyses. While more in-depth custom analysis may still be needed for some sensor types (e.g., advanced correction methods), this tool provides an easy starting place for analysis. This paper highlights two case studies using the tool to explore PM_2.5 sensor performance under the conditions of wildfire smoke impacts in the Midwestern United States and the performance of O₃ sensors for a year. Full article

The potential deformation of underlying shield tunnels caused by extensive excavations in soft soil presents a significant practical concern. In this paper, the deformation of operating twin metro shield tunnels of Shenzhen Metro Line 2 caused by large upper excavation in soft soils is investigated. The field monitoring data vividly portrays the noteworthy tunnel deformations witnessed during the construction of excavation. A three-dimensional numerical model was established to analyze the deformation response of the underlying twin tunnels and surrounding soils. Various protective measures were explored to mitigate the potential impacts of the excavation on the tunnel deformation and structural stress, including sequential excavation, staggered excavation and soil improvement. The results indicate that the deformation of the underlying operating tunnel and surrounding soil’s deformation can be effectively alleviated by properly adjusting the excavation procedure. Compared to the sequential excavation procedure, the adoption of staggered excavation procedure can reduce the vertical deformation of the operating tunnel by at least 11.2% and maximum of 24.89% with the optimal procedure. Soil improvement is not recommended to alleviate tunnel deformation when the depth of the improvement zone is shallow. The outcomes of this study hold valuable insights for safeguarding metro tunnels beneath soft soil excavation. Full article

The increasing demand for sustainable construction materials has underscored the limitations of conventional interlocking paving blocks (IPBs), particularly regarding durability, mechanical performance, and environmental impact. To overcome these shortcomings, this study proposes an integrated strategy of incorporating various waste materials in the production of IPBs namely: Untreated and surface-treated crumb rubber (CR) as a partial sand replacement at levels of 10%, and 20%; ceramic powder (CP) and glass powder (GP) as cement partial replacement at levels of 10%, 20%, and 30%, recycled ceramic as a full replacement of dolomite; and discrete fibers (basalt, polypropylene, and glass). A series of experimental tests was conducted to assess the slump, compressive and flexural strengths, water absorption, abrasion resistance, and microstructure of the proposed IPBs. The results of this study revealed that while untreated CR reduced workability and strength, it enhanced flexural resistance. Surface treatments of CR using CP and GP improved bonding and reduced porosity, with 20% CP yielding the best performances of 17.3% and 20% increases in compressive and flexural strength, respectively. Among fibers, 0.6% basalt fiber offered optimal strength and abrasion resistance (0.20 mm), while 0.6% polypropylene fiber achieved the lowest water absorption (3.70%) and a minimum abrasion depth of 0.28 mm at TR20CP mix. Microstructure analyses confirmed denser microstructure and stronger interfacial bonding in treated and fiber-reinforced mixes. This work offers a scalable, waste-based enhancement strategy for producing more durable and sustainable production of IPBs. Full article

To explore the induction of low temperature the Tiger Puffer (Takifugu rubripes) In this study, the influence of temperature on the pituitary gland during masculinization was investigated through chronic hypothermia stress experiments. Metabolomics was used to analyze the metabolic regulatory network of the pituitary gland under hypothermia stress. ELISA technology was employed to determine the activity content of oxidative stress-related enzymes in the pituitary gland. Further, TUNEL fluorescence labeling and qPCR were used to detect the apoptosis level of pituitary cells. Finally, to assess the impact of low-temperature stress on muscle tissue, HE staining and qPCR techniques were employed. The results showed that after 45 days of low-temperature stress, the differential metabolites of the pituitary gland were mainly enriched in the amino acid metabolic signaling pathway, and the contents of amino acids such as GSH and its synthetic precursors in the pituitary tissue changed significantly. The contents of oxidative stress indicators such as ROS and MDA all showed a trend of first increasing and then decreasing. The qPCR results of TUNEL fluorescence labeling and apoptosis-related genes were consistent, indicating that the apoptotic level of pituitary cells first increased and then decreased with the stress process. Histological analysis revealed that low temperature led to muscle cell atrophy and increased interstitial space in muscle tissue. The expression changes in genes related to muscle development further confirmed that low temperature significantly inhibited muscle growth and development. Therefore, this study speculates that after being subjected to chronic low-temperature stress, the pituitary gland of the red-finned Oriental pufferfish can alleviate the oxidative stress response of the body by strengthening the amino acid metabolic pathway, and the fish body has shown a physiological trend of gradually adapting to low-temperature stress, but the growth and development of muscles are still significantly inhibited. The results of this study can provide theoretical support for understanding the physiological adaptation mechanism of the red-finned Oriental pufferfish to low-temperature stress and lay a foundation for subsequent in-depth exploration of the pituitary response mechanism to low temperatures. Full article

This study extends research on sustainability transformation by investigating how power dynamics operate across organizational boundaries to enable or constrain substantive change. Using a mixed-methods approach combining survey data (n = 127) from sustainability professionals across multiple sectors and in-depth interviews (n = 18) with transformation leaders, this research identifies how organizations address power asymmetries in supply chains and multi-stakeholder partnerships. Exploratory statistical analysis indicates that inter-organizational power mobilization is associated with the effectiveness of integration mechanisms (β = 0.36, p < 0.01), with digital transparency tools showing the strongest association with integration across boundaries (β = 0.41, p < 0.01). Qualitative findings reveal three critical pathways for addressing power dynamics: technological transparency mechanisms, collaborative governance structures, and capability building networks. The research contributes to sustainability science by advancing understanding of how organizations can move beyond internal transformation to address systemic sustainability challenges through approaches that consider power relationships across organizational boundaries. The findings offer preliminary guidance for practitioners seeking to enhance sustainability impact through strategic management of inter-organizational power dynamics. Full article

The plant microbiome is pivotal to sustainable agriculture and global food security, yet some challenges hinder fully harnessing it for field-scale impact. These challenges span measurement and integration, ecological predictability and translation across environments and seasons. Key obstacles include technical challenges, notably overcoming the limits of current sequencing for low-abundance taxa and whole-community coverage, integrating multi-omics data to uncover functional traits, addressing spatiotemporal variability in microbial dynamics, deciphering the interplay between plant genotypes and microbial communities, and enforcing standardized controls, metadata, depth targets and reproducible workflows. The rise of synthetic biology, omics tools, and artificial intelligence offers promising avenues for engineering plant–microbe interactions, yet their adoption requires regulatory, ethical, and scalability issues alongside clear economic viability for end-users and explicit accounting for evolutionary dynamics, including microbial adaptation and horizontal gene transfer to ensure durability. Furthermore, there is a need to translate research findings into field-ready applications that are validated across various soils, genotypes, and climates, while ensuring that advances benefit diverse regions through global, interdisciplinary collaboration, fair access, and benefit-sharing. Therefore, this review synthesizes current barriers and promising experimental and computational strategies to advance plant microbiome research. Consequently, a roadmap for fostering resilient, climate-smart, and resource-efficient agricultural systems focused on benchmarked, field-validated workflows is proposed. Full article

The recovery of rare earth elements (REEs) from the spent NdFeB magnets has great strategic significance for ensuring the security of critical mineral resources. This process requires scientifically designed separation technologies to ensure high output and purity of the obtained rare earths. Hydrometallurgy has been widely applied to extract REEs from spent permanent magnets. This paper summarizes and reviews hydrometallurgical technologies, mechanisms, and applications for the separation and recovery of REEs and iron (Fe) from the spent permanent magnets. Key methods include: The hydrochloric acid total solution method, where the spent NdFeB is completely dissolved in hydrochloric acid, iron is precipitated and removed, and then REEs are extracted. The hydrochloric acid preferential dissolution method, where spent NdFeB magnets are first fully oxidized by oxidative roasting, converting Fe²⁺ to Fe³⁺, which hydrolyzes to Fe(OH)₃, and is precipitated and removed, allowing for the subsequent extraction of REEs to obtain rare earth oxides. Acid baking and water leaching, where spent NdFeB is calcined with acidification reagents, and the calcined products are dissolved in water to leach out REEs. At the same time, Fe is retained in the leaching residue. Electrolysis in aqueous solution, where Fe is electrolyzed at the anode or deposited at the cathode to separate it from REES. Organic acids leaching, where organic acids dissolve metals through acidolysis and complexation. Bioleaching, which utilizes microorganisms to recover metal through biological oxidation and complexation. Ionic liquid systems, where Fe or REEs are extracted using ionic liquid or leached by deep eutectic solvents. This paper provides an in-depth discussion on the challenges, advantages, and disadvantages of these strategies for recycling spent NdFeB magnets, as well as the leaching and extraction behavior of REEs. It focuses on environmental impact assessment, improving recovery efficiency, and decreasing reagent consumption. The future development direction for recycling spent NdFeB magnets is proposed, and a research idea of proposing a combined process to avoid the drawbacks of a single recycling method is introduced. Full article

Transcatheter aortic valve implantation (TAVI) is the default therapy for most elderly patients with severe aortic stenosis, but outcomes in complex anatomy depend on imaging-guided planning and disciplined technique. This article aims to present our institutional approach, supported by the current literature, in managing several challenging anatomical scenarios. We focus on seven high-impact scenarios—bicuspid aortic valve (BAV), hostile transfemoral access, iliofemoral/aortic tortuosity, adverse aortic angulation, heavy annulus/Left Ventricular Outflow Tract (LVOT) calcification, small annulus, and risk of coronary obstruction—and propose a practical approach to minimize the risk of complications. In BAV, current generation transcatheter heart valves (THV) achieve favorable early outcomes when sizing accounts for supra-annular constraints and implantation depth is tailored. Transfemoral access remains dominant in contemporary registries, yet a meaningful minority of cases require adjunctive peripheral vascular intervention to enable THV delivery-system passage. In case of annulus or LVOT calcification, small annuli, complex aortic anatomy, high risk for coronary obstruction, and pre-procedural Computed Tomography (CT) allow for an accurate sizing of THV and tailored procedural planning. A structured, CT-driven pathway that links anatomic findings to specific facilitation and bailout steps can standardize decision-making and improve safety across these challenging scenarios. We strongly highlight the importance to build a network where most complex procedures are carried out in Valve Centers where expert operators are trained to manage high volume, high complexity, and difficult complications. Full article