Search Results (71)

Coal rock is characterized by numerous cracks, which significantly impact its mechanical properties, such as fracture evolution and strength. In this study, various fracture network models were created using three-dimensional (3D) printing technology. Employing rigid adhesive and different proportions of coal powder, coal-like samples with intricate fracture networks were successfully fabricated. To replicate the mechanical properties of natural coal rocks, uniaxial compression tests were conducted to investigate the mechanical characteristics and failure modes of samples with different coal powder ratios. Additionally, the mechanical response of samples with discrete fracture network (DFN) models was evaluated after freezing treatment. Findings revealed that increasing the coal powder content enhanced the strength of the samples, whereas the introduction of the DFN model reduced their compressive strength. Samples containing the DFN model predominantly exhibited longitudinal fractures as their failure mode, contrasting with the shear fractures observed in the solid model samples. Furthermore, under low-temperature conditions, the artificial specimens exhibited a distinct trend, where brittleness increased proportionally with coal powder content, a phenomenon attributed to the influence of AB adhesive. After applying freezing treatment to DFN model coal-like samples, stress–strain curves resembling those of actual coal rocks were observed, along with a slightly reduced compressive strength and a brittle failure mode characterized by oblique shear failure. Full article

This study investigates the decoupling relationship between industrial carbon emissions and economic development in the Beibu Gulf City Cluster based on panel data from 2005 to 2022. It also uses the Tapio decoupling model to assess the degree of decoupling and synergy in Guangdong, Guangxi, and Hainan and combines it with the logarithmic mean differential index (LMDI) decomposition model to study the driving factors affecting industrial carbon emissions. The study indicates that the industrial carbon emissions of the Beibu Gulf City Cluster increases from 71.42 MT in 2005 to 108.29 MT in 2022 but peaks in 2020 and changes from weak decoupling to strong decoupling; the synergistic relationship among Guangdong, Guangxi, and Hainan will evolve from poor to favorable. The LMDI decomposition results show that the economic scale and population scale effects increase 157.05 MT and 11.67 MT of carbon emissions in the study period, while the optimization of energy structure and energy intensity reduces 117.26 MT and 19.60 MT of carbon emissions, respectively, and the industrial development of many cities in the Beibu Gulf region gradually decouples economic growth and carbon emissions after 2021. Based on this, this study proposes targeted measures to reduce carbon emissions from industrial production in the Beibu Gulf City Cluster, which is of constructive significance for promoting sustainable industrial development in the region. Full article

The B3 transcription factor superfamily, crucial for plant growth and stress adaptation, remains poorly characterized in cucumber (Cucumis sativus), a globally important vegetable crop. Here, we conducted the first genome-wide identification of 52 B3 superfamily genes in cucumber, classifying them into LAV, ARF, RAV, and REM subfamilies through integrated phylogenetic and structural analyses. These genes exhibited conserved B3 domains with lineage-specific motif architectures and diverse exon–intron organizations, particularly within the structurally divergent REM subfamily. Collinearity analysis revealed segmental duplication as a key driver of family expansion, notably between syntenic REM clusters on chromosomes 2 (CsREM5-7) and 6 (CsREM18-20). Promoter cis-element profiling identified enrichment in hormone-responsive and stress adaptation motifs, suggesting functional diversification in signaling pathways. Furthermore, tissue-specific expression divergence was observed across 10 organs, with ARF members displaying broad regulatory roles and REM genes showing apical meristem enrichment. Strikingly, CsRAV8 exhibited glandular trichome-specific expression, a novel finding, given Arabidopsis RAVs’ lack of trichome-related functions. Spatial validation via in situ hybridization localized CsRAV8 transcripts to trichome glandular head cells. Functional investigation using virus-induced gene silencing (VIGS) demonstrated that CsRAV8 suppression caused significant glandular trichome shriveling, implicating its role in maintaining glandular cavity integrity. This study provides the first comprehensive genomic inventory of B3 transcription factors in cucumber, providing evolutionary insights and functional frameworks for future functional genomics studies. Full article

This study proposes a grading algorithm for Orah sorting lines based on machine vision and deep learning. The original ShuffleNet V2 network was modified by replacing the ReLU activation function with the Mish activation function to alleviate the neuron death problem. The ECA attention module was incorporated to enhance the extraction of Orah appearance features, and transfer learning was applied to improve model performance. As a result, the ShuffleNet_wogan model was developed. Based on the operational principles of the sorting line, a time-sequential grading algorithm was designed to improve grading accuracy, along with a multi-sampling diameter algorithm for simultaneous Orah diameter measurement. Experimental results show that the ShuffleNet_wogan model achieved an accuracy of 91.12%, a 3.92% improvement compared to the original ShuffleNet V2 network. The average prediction time for processing 10 input images was 51.44 ms. The sorting line achieved a grading speed of 10 Orahs per second, with an appearance grading accuracy of 92.5% and a diameter measurement compliance rate of 98.3%. The proposed algorithm is characterized by high speed and accuracy, enabling efficient Orah sorting. Full article

The pier-type repair equipment for bridges is a crucial branch of bridge emergency repair. However, the existing bridge pier repair equipment predominantly utilizes rod systems, which require substantial assembly work, hindering the rapid restoration of damaged bridges. Modular steel structure buildings, as a highly integrated form of prefabricated construction, can play a significant role in emergency rescue operations. Based on the modular architectural design concept, this paper proposes a new type of modular steel structure emergency repair pier joint that facilitates rapid assembly and connection between modular units. Using ABAQUS 2022 software to establish a finite element model of the joint, the bending performance under lateral displacement loads perpendicular to the joint opening direction (X-direction in the model coordinate system) and parallel to the joint opening direction (Z-direction in the model coordinate system) is analyzed. The influence of the width-to-thickness ratio of the upper corner piece base plate D/t₁ (where D is the width of the upper corner piece base plate and t₁ is the thickness of the upper corner plate), the height-to-thickness ratio of the lower corner piece top plate h/t₂ (where h is the height of the protrusion of the lower corner piece and t₂ is the thickness of the lower corner piece top plate), the height of the protrusion of the lower corner piece (h), and the bolt diameter (d) on the bending performance of the joint is investigated. Recommendations for the design values of the joint are provided. Then, the flexural behavior of the joint under 0.1, 0.2, and 0.3 axial compression ratios is studied, respectively. The results show that with the increase of axial compression ratio, the yield rotation angle and ultimate rotation angle of the joint decrease, and the bearing capacity decreases faster after the joint reaches the ultimate bearing capacity. When the joint is subjected to the X-direction horizontal lateral displacement load, the initial flexural stiffness and flexural capacity of the joint increase with an increase in the axial compression ratio. When subjected to the horizontal lateral displacement load in the Z-direction, the initial bending stiffness of the joint increases with an increase in the axial compression ratio, and the bending capacity does not change much. In addition, the joint is classified; from the perspective of load-bearing capacity, it is a partially resistant joint, and from the perspective of stiffness, it is a semi-rigid joint. Finally, a simplified calculation model for the joint is proposed based on the component method. Full article

This paper introduces a new self-locking-unlockable modular building with an inter-module connection, and its seismic performance is investigated. The new connection can realize fast connection and unlocking during construction through exceptional design. In this paper, taking the Tianjin Binhai Apartment project as the background, for the actual force situation of the new connection, considering the influence of corrugated steel plate stiffness, a simplified model of the connection is constructed by using multi-fold elastic connection, and the corrugated steel plate stiffness is simulated with equivalent support. In the MIDAS Gen 2021 software, the five-story and six-story structural models using traditional rigid connections and new connections were established, respectively, and reaction spectrum analysis was carried out. Meanwhile, seismic waves that comply with codes were selected for dynamic time course analysis. The results show that the stress ratios of all components of the new connection model and the traditional rigid model are less than 1. Among them, the maximum stress ratios of both floor beams are 0.745 and 0.725, respectively; the maximum stress ratios of the modular columns are 0.655 and 0.494, respectively; the stress ratios of the ceiling beams are all less than 0.5; and the two models show good strength and stiffness reserves, following the design principle of strong columns and weak beams and verifying the reliability of the new connection model. Meanwhile, it is found that the inter-story displacement angle of the six-story structure with the new connections is less than the normative value under the action of rare earthquakes, and the difference in top displacement is about 18% compared with that of the rigid structure, so it is suggested that the new connections can be applied within the height of six stories. Full article

Cucumber (Cucumis sativus L.) is one of the most widely cultivated crops worldwide and is valued for its nutritional, economic, and ecological benefits. The regulation of defense mechanisms against herbivores, along with osmotic loss and environmental regulation, is greatly affected by trichomes in cucumbers. In this study, we attempted to characterize trichomes and examined fruit physiological and transcriptome profiles by RNA sequencing in cucumber breeding lines 6101-4 and 5634-1 at three stages of fruit development through foliar application with a combination of silver nitrate (AgNO₃) and sodium thiosulfate (Na₂S₂O₃) in comparison to non-treated controls. Notable increases in the number of trichomes and altered forms were observed for both inbred cultivars 6101-4 and 5634-1 against foliar application of chemical substances. RNA-seq analysis was performed to identify differentially expressed genes (DEGs) involved in multiple pathways in cucumber trichome formation. The enrichment of differentially expressed transcripts showed that foliar application upregulated the expression of many stress-responsive and trichome-associated genes including plant hormone signal transduction, sesquiterpenoid and triterpenoid biosynthesis, and the mitogen-activated protein kinase (MAPK) signaling pathway. The dominant regulatory genes, such as allene oxide synthase (AOS) and MYB1R1 transcription factor, exhibited significant modulations in their expression in response to chemical application. The RNA-seq results were further confirmed by RT-PCR-based analysis, which revealed that after chemical application, the dominant regulatory genes, such as allene oxide synthase (AOS), PTB 19, MYB1R1, bHLH62-like, MADS-box transcription factor, and salicylic acid-binding protein 2-like, were differentially expressed, implying that these DEGs involved in multiple pathways are involved the positive regulation of the initiation and development of trichomes in C. sativus. A comparison of trichome biology and associated gene expression regulation in other plant species has shown that silver nitrate (AgNO₃) and sodium thiosulfate (Na₂S₂O₃) are also responsible for hormonal and signaling pathway regulation. This study improves our knowledge of the molecular mechanisms involved in C. sativus trichome development. It also emphasizes the possibility of utilizing chemical composition to modulate C. sativus trichome-related characteristics of C. sativus, leading to the improvement of plant defense mechanisms as well as environmental adaptation. Full article

To address the issues of pipeline corrosion and erosion during ground testing, this paper presents an innovative electromagnetic ultrasonic thickness measurement system that utilizes ZigBee wireless communication technology. The system employs a ZigBee mesh topology for creating a wireless distributed network, where node devices carry out multi-point monitoring in a configuration of “one master, multiple”. Each node is powered by an STM32 embedded control chip and fitted with ultrasonic sensors. Slave nodes transmit the real-time data they collect to a server via the master node, thus enabling remote monitoring of the system through a web interface. The system incorporates an enhanced data filtering algorithm, allowing for precise monitoring of the pipeline wall thickness and providing immediate data feedback. An experimental validation of the system’s stability and long-distance transmission capabilities was performed on a simulated platform, confirming its viability and applicability for real-world engineering applications. Full article

Satellite remote sensing complements rain gauges and ground radars as the primary sources of precipitation data. While significant advancements have been made in spaceborne precipitation estimation since the 1960s, the emergence of multi-sensor precipitation estimation (MPE) in the early 1990s revolutionized global precipitation data generation by integrating infrared and microwave observations. Among others, Global Precipitation Measurement (GPM) plays a crucial role in providing invaluable data sources for MPE by utilizing passive microwave sensors and geostationary infrared sensors. MPE represents the current state-of-the-art approach for generating high-quality, high-resolution global satellite precipitation products (SPPs), employing various methods such as cloud motion analysis, probability matching, adjustment ratios, regression techniques, neural networks, and weighted averaging. International collaborations, such as the International Precipitation Working Group and the Precipitation Virtual Constellation, have significantly contributed to enhancing our understanding of the uncertainties associated with MPEs and their corresponding SPPs. It has been observed that SPPs exhibit higher reliability over tropical oceans compared to mid- and high-latitudes, particularly during cold seasons or in regions with complex terrains. To further advance MPE research, future efforts should focus on improving accuracy for extremely low- and high-precipitation events, solid precipitation measurements, as well as orographic precipitation estimation. Full article

Multipath is a source of error that limits the Global Navigation Satellite System (GNSS) positioning precision in short baselines. The tightly combined model between systems increases the number of observations and enhances the strength of the mathematical model owing to the continuous improvement in GNSS. Multipath mitigation of the multi-GNSS tightly combined model can improve the positioning precision in complex environments. Interoperability of the multipath hemispherical map (MHM) models of different systems can enhance the performance of the MHM model due to the small multipath differences in single overlapping frequencies. The adoption of advanced sidereal filtering (ASF) to model the multipath for each satellite brings computational challenges owing to the characteristics of the multi-constellation heterogeneity of different systems; the balance efficiency and precision become the key issues affecting the performance of the MHM model owing to the sparse characteristics of the satellite distribution. Therefore, we propose a modified MHM method to mitigate the multipath for single-frequency multi-GNSS tightly combined positioning. The method divides the hemispherical map into 36 × 9 grids at 10° × 10° resolution and then searches with the elevation angle and azimuth angle as independent variables to obtain the multipath value of the nearest point. We used the k-d tree to improve the search efficiency without affecting precision. Experiments show that the proposed method improves the mean precision over ASF by 10.20%, 10.77%, and 9.29% for GPS, BDS, and Galileo satellite single-difference residuals, respectively. The precision improvements of the modified MHM in the E, N, and U directions were 32.82%, 40.65%, and 31.97%, respectively. The modified MHM exhibits greater performance and behaves more consistently. Full article

Silicone rubber (SIR) is a crucial insulating material in cable accessories, but it is also susceptible to faults. In practical applications, mechanical pressure from bending or shrinking can impact the degradation of SIR, necessitating the study of its electrical tree and partial discharge (PD) characteristics under such pressure. This work presents the construction of a test platform for electrical trees under varying pressures to observe their growth process. A high-frequency current transformer is used to measure PD patterns during tree growth, enabling analysis of the effect of PD on tree initiation and propagation under pressure. The experimental results demonstrate a significant decrease in tree inception probability and increase in PD inception voltage under pressure. The pressure also influences the tree structure and PD during the treeing process, where the longest tree with a branch-like structure appears under 800 kPa. The effect of pressure on electrical tree and PD characteristics can be attributed to changes in free volume, alterations in air pressure within the tree channels, and the affected charge accumulation. Full article

The external cooling water system of a 300 Mvar dual internal water cooling synchronous condenser at a certain ultra-high voltage converter station continued to exhibit significant scaling and corrosion, even with regular addition of scale and corrosion inhibitors. To solve this problem, the external cooling water of the synchronous condenser was sampled and tested periodically, with the main test items including conductivity, pH value, turbidity, hardness, alkalinity, and other water quality parameters directly related to corrosion and scaling. The trends of these parameters over time were also analyzed. The results showed that as the operation time increased, the cooling water became concentrated during multiple circulation cycles, and the various dissolved or suspended substances underwent a certain degree of enrichment. However, the addition of scale and corrosion inhibitors did not dynamically adjust according to the changes in water quality, and there was always an excessive dosage. Thus, using the external cooling water as the experimental sample, static scale inhibition tests and rotating coupon corrosion tests were conducted to evaluate the scale and corrosion inhibition performance of the commercial AS-582 scale and corrosion inhibitor used at this ultra-high voltage converter station under different conditions. Considering the more obvious corrosive tendency of this water sample, the focus was on testing its corrosion inhibition performance. When the dosage was 600 ppm, the scale inhibition effect was optimal, with an inhibition rate of 92.15%. The corrosion inhibition effect of this scale and the corrosion inhibitor were significantly related to water temperature. At 25 °C, when the dosage was 500 ppm, the corrosion inhibition effect was optimal, with an inhibition rate of 86.79%. However, when the temperature increased to 40 °C, the corrosion inhibition effect under each dosage was significantly worse, unable to meet the requirements, and the use of other corrosion inhibitors in combination was necessary. This work will provide a reference for the scientific use of scale and corrosion inhibitors. Full article

Scientific and reasonable satisfaction evaluation is an excellent way to understand the effects of building (structure) renovation and public satisfaction. This study presents a satisfaction evaluation of civil air defense engineering renovated into cooling place from the perspective of public experience. First, a satisfaction evaluation indicator system was constructed for civil air defense engineering renovated into cooling place from the perspective of public experience, focusing on 5 first-level indicators—location condition, spatial status, physical environment, service management, and emotional experience—and 27 second-level indicators. Second, the matter-element extension and combined weighting method were introduced to establish a satisfaction evaluation model for civil air defense engineering renovated into cooling place from the perspective of public experience. Finally, the rationality of the index system and feasibility of the evaluation model were verified by considering civil air defense cooling centers as examples. This research can provide a basis for the further optimization of such projects and the development and management of cities, as well as new ideas or methods for the satisfaction evaluation of similar old buildings (structures) after renovation. Full article

Soil cadmium contamination poses a significant threat to global food security and human health, making the timely and accurate diagnosis of cadmium stress in rice crucial for effective pollution control and agricultural management. However, during the early growth stages of rice, particularly the tillering stage, the spectral response to cadmium stress is subtle, rendering traditional remote sensing methods inadequate. This study aims to develop an efficient early diagnosis index, the Cadmium Early Stress Index (CESI), for rapid and accurate detection of cadmium stress in rice at a regional scale. By integrating field surveys with Sentinel-2 satellite data, the study extracts multi-angle spectral features and employs an enhanced Generalized Additive Model Neural Network (E-GAMI-Net) for analysis. E-GAMI-Net analysis identified key indicators for early diagnosis, including log-transformed reflectance at 941 nm (R941_log), Optimized Soil-Adjusted Vegetation Index (OSAVI), and the interaction between Red Edge Amplitude and Chlorophyll content. Based on these findings, CESI was constructed, demonstrating superior diagnostic performance (R² = 0.77, RMSE = 0.09 mg/kg) compared to existing methods. CESI also exhibited high stability under noise interference, with only a 5.6% reduction in R² under 15% noise. In regional-scale remote sensing applications, CESI successfully generated cadmium stress distribution maps, identifying previously undetected moderate stress areas. CESI’s high accuracy (R² = 0.6073, RMSE = 0.3021) and stability make it a promising tool for large-scale cadmium stress monitoring and precision agriculture management. Full article

Atmospheric water vapor is not only a key element of the global hydrological cycle but also the most abundant greenhouse gas. The phase transition and transportation of water vapor are essential for maintaining global energy balance and regulating hydrological processes. However, due to insufficient meteorological observational data, climate research in Africa faces significant limitations despite its substantial contribution to changes in global precipitable water vapor (PWV). In this study, we used MODIS near-infrared (NIR) PWV products and Berkeley temperature data to depict the spatial–temporal variability in PWV across Africa from 2001 to 2020. The results reveal a significant increasing trend in PWV over Africa, with an increase of 0.0158 cm/year. Nearly 99.96% of Africa shows an increase in PWV, with 88.95% of these areas experiencing statistically significant changes, particularly in central regions of Africa. The increase in PWV is more pronounced in high-value months compared to low-value months. The equatorial region of the Congo Basin exhibits higher PWV, which gradually decreases as latitude increases. Despite significant warming (0.0162 °C/year) in Africa, there is no consistent positive correlation between temperature and water vapor. A positive relationship between PWV and temperature is observed in western Africa, while a negative relationship is noted in eastern and southern Africa on an annual scale. Additionally, an increasing trend in precipitation (4.6669 mm/year) is observed, with a significant positive correlation between PWV and precipitation across most of Africa, although this relationship varies by month. These findings provide valuable insights into the comprehension of the hydrothermal variation in Africa amidst climate warming. Full article