Higher Leak Rate Research Articles

Evaluating the Impact of Elective Endotracheal Tube Replacement on Postoperative Outcomes in Esophageal Atresia: A STROBE-guided Study

ABSTRACT Background: Elective ventilation and paralysis have been shown to decrease the anastomosis-related complications following primary repair of esophageal atresia (EA). Repeated endotracheal tube (ETT) block and replacement can increase these complications. We evaluated the results of our strategy of electively changing the ETT just before shifting the patient to the postoperative ward for elective ventilation. Materials and Methods: A retrospective study was conducted using the case records of patients from July 2015 to February 2024 including all the patients of EA with tracheoesophageal fistula who underwent primary repair with end-to-end esophageal anastomosis. The patients were divided into two groups Group A: ETT was changed and Group B: ETT was not changed immediately before shifting. The groups were compared for anastomotic leak and ETT tube block in the first 48 h. Results: Ninety-one patients were included in the study, 36 in Group A and 55 in Group B. Elective replacement of ETT decreased the tube block rates in the first 48 h following surgery (P = 0.032). Tension in the anastomosis was associated with a higher leak rate. The leak was present in 58.3% and 3.6% in cases with and without tension in the anastomosis (P = 0.001). Overall, the anastomotic leak was similar in both groups. In the subgroup of patients with anastomosis under tension, the rate of anastomotic leak was higher in patients with ETT block (P = 0.028). Conclusion: Elective replacement of EET decreases the tube block rates and anastomotic leak rates in cases with anastomosis under tension.

Structure Equation Model for Costs and Benefits of Distribution Pipe Rehabilitation in Reactive Maintenance

Some water distribution pipe networks were constructed several decades ago and have been damaged. The old pipe network has experienced many leaks and should be rehabilitated. In old cities like Jakarta, with high leak rates (1.6 leaks/km/year), pipeline network managers must frequently repair leaks or perform reactive maintenance. Far too many pipes need to be rehabilitated compared to the available budget. This research will develop an optimization model for selecting rehabilitated pipes under reactive maintenance conditions, which has never been performed before. The selection of pipe segments to be rehabilitated must be optimal to obtain maximum benefits using minimum costs. The variables that influence rehabilitation costs and benefits and the relationship between these variables need to be known to optimize the selection. The influencing variables and their model structure were obtained from literature reviews and surveys of respondents with sufficient experience in water pipe network management. These influential variables have varying characteristics. Data processing and analysis uses the confirmatory factor analysis (CFA) method with a formative–formative measurement model. In total, 22 variables were found to be valid and significantly influenced the cost and benefits of rehabilitation. The analysis results are a structural model of the relationship between variables that influence the costs and benefits of rehabilitation in reactive maintenance with a limited budget, which can be used to optimize rehabilitation models.

Improved catalytic stability of immobilized Candida antarctica lipase B on macroporous resin with organic polymer coating for biodiesel production.

Lipase is one of the most widely studied and applied biocatalysts. Due to the high enzyme leakage rate of the immobilization method of physical adsorption, we propose a new lipase immobilization method, based on the combination of macroporous resin adsorption and organic polymer coating. The immobilized Candida antarctica lipase B (CALB@resin-CAB) was prepared by combining the macroporous resin adsorption with cellulose acetate butyrate coating, and its structure was characterized by various analytic methods. Immobilized lipase was applied for biodiesel production using acidified palm oil as the starting material, the conversion rate achieved as high as 98.5% in two steps. Furthermore, the immobilized lipase displayed satisfactory stability and reusability in biodiesel production. When the aforementioned reaction was carried out in a continuous flow packed bed system, the yield of biodiesel was 94.8% and space-time yield was 2.88g/(mL∙h). The immobilized lipase CALB@resin-CAB showed high catalytic activity and stability, which has good potential for industrial application in the field of oil processing.

Research on a Metal Surface Defect Detection Algorithm Based on DSL-YOLO

In industrial manufacturing, metal surface defect detection often suffers from low detection accuracy, high leakage rates, and false detection rates. To address these issues, this paper proposes a novel model named DSL-YOLO for metal surface defect detection. First, we introduce the C2f_DWRB structure by integrating the DWRB module with C2f, enhancing the model’s ability to detect small and occluded targets and effectively extract sparse spatial features. Second, we design the SADown module to improve feature extraction in challenging tasks involving blurred images or very small objects. Finally, to further enhance the model’s capacity to extract multi-scale features and capture critical image information (such as edges, textures, and shapes) without significantly increasing memory usage and computational cost, we propose the LASPPF structure. Experimental results demonstrate that the improved model achieves significant performance gains on both the GC10-DET and NEU-DET datasets, with a mAP@0.5 increase of 4.2% and 2.6%, respectively. The improvements in detection accuracy highlight the model’s ability to address common challenges while maintaining efficiency and feasibility in metal surface defect detection, providing a valuable solution for industrial applications.

NiCo@EG-based composite PCMs with boosted thermal conductivity and photothermal conversion efficiency for solar energy harvesting

The application of phase change materials (PCMs) in solar energy is hampered by challenges such as insufficient photothermal conversion efficiency, low thermal conductivity and leakage. In this study, a novel composite PCMs based on NiCo@EG were prepared to solve the problems of low thermal conductivity, high leakage rate and inefficient photothermal performance. The NiCo@EG is obtained through calcination of the product of Ni-Co-BTC in-situ on expanded graphite (EG). In the composite PCMs, the octadecanol (OD) acts as a latent heat storage unit, the EG retains its porous network structure as an encapsulating skeleton. The nickel and cobalt nanoparticles derived from Ni-Co-BTC bimetallic organic frameworks are uniformly fixed on the surface of the EG, which could not only construct multiple thermal conduction pathways, but also enhance the photon-trapping ability. Benefiting from the synergy effect of nickel, cobalt metal nanoparticles and EG, the prepared OD/NiCo@EG-550 composite PCMs display high latent heat (168.3 J/g), excellent photothermal conversion efficiency (98.71 %), and improved thermal conductivity of 12.873 W/(m·K). Furthermore, the composite PCMs demonstrate exceptional shape stability, thermal stability, and robust thermal reliability. In summary, the high-efficiency photothermal composite PCMs display significant potential in improving the utilization of solar energy.

Parametric Analysis and Numerical Optimization of Root-Cutting Shovel of Cotton Stalk Harvester Using Discrete Element Method

Aiming at solving the problems of the high cost of manual pulling, the low reliability of existing pulling devices, and the high breaking rates and high leakage rates in the process of cotton stalk reuse after removal from the field in the Xinjiang cotton area, a soil-loosening and root-cutting cotton stalk pulling and gathering machine was researched and designed; a root-cutting force model was established; the key parameters of the V-shaped root-cutting knife were calculated and optimized; and the ranges of the slide cutting angle, the cutting-edge angle, and the soil entry angle were determined. A shoveling process simulation of the V-shaped root-cutting knife and the root–soil complex was constructed, and the working mechanism of the V-shaped root-cutting knife was clarified. In order to verify the reliability and operation performance of the V-shaped root-cutting knife, the slide cutting angle, the cutting-edge angle, and the soil entry angle were used as the test factors, and a response surface test with three factors and three levels was carried out with the root-breaking force and the mean value of the cutting resistance as the test indices. The test results were analyzed by variance analysis, and the significant factors influencing the root-breaking force in descending order were the slide cutting angle, cutting-edge angle, and soil entry angle. The degrees of influence on the mean value of the cutting resistance were ordered as follows: slide cutting angle, soil entry angle, and cutting-edge angle. In order to make the V-shaped root-cutting knife achieve the optimal working state, the parameters of the test indices were optimized, and the optimal design parameters of the V-shaped root-cutting knife were set as follows: the slide cutting angle was 48.3°, the cutting-edge angle was 43.4°, and the soil entry angle was 26.2°. The field uprooting test showed that the average pass rate of root breakage was 94.8% and the average pull-out rate of cotton stalks was 93.2%. This study provides theoretical guidance for the development of a root-breaking mechanism for cotton straw harvesters.

Chitosan-based bilayer shell phase change nano-capsules with excellent anti-permeability for thermal regulation dressings

Nano-encapsulated phase change materials (NEPCMs) with appropriate phase change temperature range and excellent anti-permeability have significant application value in the field of thermal regulation dressings. In this study, NEPCMs were synthesized using the microemulsion polymerization method, with eutectic fatty acids (LA-SA) as the core material and poly(methyl methacrylate) (PMMA) as the shell material. Subsequently, using the electrostatic adsorption method, chitosan (CS) was successfully coated onto the outer surface of NEPCMs, resulting in the preparation of a novel bilayer shell nano-encapsulated phase change materials (BS-NEPCMs) for thermal regulation dressings. The impact of core/shell ratio, CS acid solution concentration and cross-linking agent content on capsule properties was investigated. It was found that BS-NEPCMs exhibited excellent cyclical stability and thermal stability. In particular, the CS shell layer provided excellent interfacial impermeability effects for the capsules, achieving an anti-permeability efficiency of 96.21 %. This not only helps address the problem of high leakage rates in single wall capsules, but also ensures that the capsules maintain high phase change enthalpies of 99.32 J/g and 96.38 J/g, respectively. The dressings based on BS-NEPCMs demonstrated good thermal regulation at 33–42 °C with maximum phase change enthalpies of 39.53 J/g and 34.08 J/g, respectively. Swelling and rheological analysis showed that the dressing exhibits a gel state, with a swelling ratio of 343 %, an elastic modulus of 15 kPa and a viscous modulus of 4 kPa. This study indicated that BS-NEPCMs hold significant promise for various applications in energy storage and body thermal regulation fields.

Phase change materials encapsulated in graphene hybrid aerogels with high thermal conductivity for efficient solar-thermal energy conversion and thermal management of solar PV panels

Phase change materials (PCMs) have a wide range of applications in latent heat storage and thermal management. However, their practical use is hindered by high leakage rates and low thermal conductivity. To address these issues, polyvinyl alcohol/carboxylated carbon nanotubes/graphene hybrid aerogels (PCG) were carbonized at high temperatures to obtain polyvinyl alcohol/carboxylated carbon nanotubes/graphene carbon aerogels (cPCG). Polyethylene glycol (PEG) was then encapsulated within cPCG to form cPCG@PEG shape-stabilized PCMs (SSPCMs). These cPCG@PEG SSPCMs demonstrated excellent thermal conductivity (0.843 W•m-1•K-1) and superior solar-thermal conversion performance (91.8%). Additionally, the latent heat of cPCG@PEG showed a minimal decrease even after 100 melt-crystallization cycles. An experimental setup was designed to regulate the temperature of solar photovoltaic (PV) panels using cPCG@PEG. The results indicated that cPCG@PEG effectively managed the temperature of solar PV panels under varying light conditions. This study presents a novel approach for enhancing the application of porous PCMs in solar energy utilization and thermal management of equipment.

Low doses of acetyl trihexyl citrate plasticizer promote adipogenesis in hepatocytes and mice.

Accumulating epidemiological evidence underscores the association between pervasive environmental factors and an increased risk of metabolic diseases. Environmental chemicals, recognized disruptors of endocrine and metabolic processes, may contribute to the global prevalence of metabolic disorders, including obesity. Acetyl tributyl citrate (ATHC), categorized as a citric acid ester plasticizer, serves as a substitute for di-(2-ethylhexyl) phthalate (DEHP) in various everyday products. Despite its widespread use and the increasing risk of exposure in humans and animals due to its high leakage rates, information regarding the safety of exposure to environmentally relevant doses of ATHC remains limited. This study aimed to investigate the potential impact of ATHC exposure on metabolic homeostasis. Both in vivo and in vitro exposure models were used to characterize the effects induced by ATHC exposure. C57BL/6J male mice were subjected to a diet containing ATHC for 12weeks, and metabolism-related parameters were monitored and analyzed throughout and after the exposure period. Results indicated that sub-chronic dietary exposure to ATHC induced an increase in body fat percentage, elevated serum lipid levels, and increased lipid content in the liver tissue of mice. Furthermore, the effect of ATHC exposure on murine hepatocytes were examined and results indicated that ATHC significantly augmented lipid levels in AML12 hepatocytes, disrupting energy homeostasis and altering the expression of genes associated with fatty acid synthesis, uptake, oxidation, and secretion pathways. Conclusively, both in vivo and in vitro results suggest that exposure to low levels of ATHC may be linked to an elevated risk of obesity and fatty liver in mice. The potential implications of ATHC on human health warrant comprehensive evaluation in future studies.

Local economic development strategy through hiking tourism: A case study of the selo trail on Mount Merbabu

Background: The existence of the Selo Hiking Trail tourist attraction also provides job opportunities for the local community to work in various business units. Method: Using Multiplier Effect analysis, this study shows that tourism activities along the Selo Trekking Trail significantly impact the livelihoods of the local community. Economically assessed through Multiplier Effect Analysis, the Keynesian Income Multiplier was found to be 0.6, with a Type I Income Multiplier Ratio of 3.3, and a Type II Income Multiplier Ratio of 3.5, highlighting the substantial economic benefits derived from tourism along the Selo Trekking Route. Result: The study indicates that the high leakage rates, particularly in transportation and logistics costs outside the tourist destination, encourage the development of new business units such as convenience stores or minimarkets, as well as gas stations to meet the needs of tourists. Conclusion: To enhance the broader economic impact of tourism, further research and development are needed, especially in the context of culture-based rural tourism or Community-Based Tourism initiatives. This approach aims to promote sustainable economic benefits while preserving cultural heritage and increasing community participation in tourism activities. Novelty/Originality of this study: This study uses Multiplier Effect Analysis to measure the economic impact of nature tourism and provides quantitative evidence of substantial economic benefits to local communities. The study also identifies new business development opportunities to reduce economic leakage, providing a framework for community-based sustainable tourism development.

Safe Transition from Open to Total Minimally Invasive Esophagectomy for Cancer Utilizing Process Management Methodology.

Background: The global shift from open esophagectomy (OE) to minimally invasive esophagectomy (MIE) for treating esophageal cancer is well-established. Recent data indicate that transitioning from hybrid minimally invasive esophagectomy (hMIE) to total minimally invasive esophagectomy (tMIE) can be challenging due to concerns about higher leakage rates and lower lymph node counts, especially at the beginning of the learning curve. This study aimed to demonstrate that a safe transition from OE to tMIE for cancer is possible using process management methodology. Methods: A step-change approach was adopted in process management planning, with hMIE serving as an intermediate step between OE and tMIE. This single-center, case-control study included 150 patients who underwent the Ivor Lewis procedure with curative intent for esophageal cancer. Among these patients, 50 underwent OE, 50 hMIE (laparoscopic procedure followed by conventional right thoracotomy), and 50 tMIE (laparoscopic and thoracoscopic approach). A preceptored training scheme was implemented during execution, and treatment results were monitored and controlled to ensure a safe transition. Results: During the transition, the tMIE group was not worse than the hMIE and OE groups regarding operation duration (p = 0.135), overall postoperative complications (p = 0.020), anastomotic leakage rates (p = 0.773), 30-day mortality (p = 1.0), and oncological outcomes (based on R status (p = 0.628) and 2-year survival (p = 0.967)). Additionally, the tMIE group showed superior results in terms of major postoperative pulmonary complications (p = 0.004) and ICU stay duration (p < 0.001). Conclusions: Utilizing managerial methodology and practice in surgery, as a bridge between interdisciplinary and transdisciplinary approaches, demonstrated that transitioning from OE to tMIE, with hMIE as an intermediate step, is safe and feasible without compromising outcomes.

Enhanced feature extraction YOLO industrial small object detection algorithm based on receptive-field attention and multi-scale features

Abstract To guarantee the stability and safety of industrial production, it is necessary to regulate the behavior of employees. However, the high background complexity, low pixel count, occlusion and fuzzy appearance can result in a high leakage rate and poor detection accuracy of small objects. Considering the above problems, this paper proposes the EFE-YOLO (Enhanced feature extraction-You Only Look Once) algorithm to improve the detection of industrial small objects. To enhance the detection of fuzzy and occluded objects, the PSRFA (PixelShuffle and Receptive-Field Attention) upsampling module is designed to preserve and reconstruct more detailed information and extract the receptive-field attention weights. Furthermore, the MSE (multi-scale and efficient) downsampling module is designed to merge global and local semantic features to alleviate the problem of false and missed detection. Subsequently, the AFAF (Adaptive Feature Adjustment and Fusion) module is designed to highlight the important features and suppress background information that is not beneficial for detection. Finally, the EIoU loss function is used to improve the convergence speed and localization accuracy. All experiments are conducted on homemade dataset. The improved YOLOv5 algorithm proposed in this paper improves mAP@0.50 (mean average precision at a threshold of 0.50) by 2.8\% compared to the YOLOv5 algorithm. The average precision and recall of small objects show an improvement of 8.1\% and 7.5\%, respectively. The detection performance is still leading in comparison with other advanced algorithms.

Real‐time fire and smoke detection with transfer learning based on cloud‐edge collaborative architecture

AbstractRecent years have seen increased interest in object detection‐based applications for fire detection in digital images and videos from edge devices. The environment's complexity and variability often lead to interference from factors such as fire and smoke characteristics, background noise, and camera settings like angle, sharpness, and exposure, which hampers the effectiveness of fire detection applications. Limited picture data for fire and smoke scenes further challenges model accuracy and robustness, resulting in high false detection and leakage rates. To address the need for efficient detection and adaptability to various environments, this paper focuses on (1) proposing a cloud‐edge collaborative architecture for real‐time fire and smoke detection, incorporating an iterative transfer learning strategy based on user feedback to enhance adaptability; (2) improving the detection capabilities of the base model YOLOv8 by enhancing the data augmentation method and introducing the coordinate attention mechanism to improve global feature extraction. The improved algorithm shows a 2‐point accuracy increase. After three iterations of transfer learning in the production environment, accuracy improves from 93.3% to 96.4%, and mAP0.5:0.95 increases by nearly 5 points. This program effectively addresses false detection issues in fire and smoke detection systems, demonstrating practical applicability.

Oxidation and spontaneous combustion characteristics of particulate coal under stress–heat–gas interactions

Coal spontaneous combustion (CSC) is disturbed by complex downhole conditions. However, current research by scholars mainly focuses on the impact of single conditional disturbances on CSC, which is difficult to comprehensively characterize the oxidation and spontaneous combustion characteristics of granular coal in a complex environment. For this reason, a temperature-programmed gas chromatographer (TP-GC) hyphenated instrument and a C600 high-precision microcalorimeter was used for analysis. The variation rules of derived gas and oxidizing thermodynamic parameters in the coal oxidizing and heating process under stress-heat-gas interaction were obtained. The intrinsic action mechanism of stress-heat-gas interaction to increase the risk of spontaneous combustion of granular coal is described. The results showed that as the level of air leakage (AL) rate increased, the concentration of derived gases in the coal sample showed a “˄”-shaped trend, and the heat release intensity and heat release varied in stages, both reaching their peak at a leakage rate of 150 mL/min. Under different stress conditions, the heat release intensity and heat release of coal also reach their maximum at 150 mL/min, indicating a higher risk of spontaneous combustion of coal at 150 mL/min. As the stress increases, the coal‑oxygen reaction is inhibited, leading to a decrease in the concentration of derived gases and a reduction in the average heat release of the coal sample. This indicates that particulate coal is prone to spontaneous combustion when subjected to high air leakage rate and low stress conditions. The experimental results provide a theoretical basis for the prevention of CSC under complex conditions.

Comparison of Post-Operative Outcomes of Right Colectomy between Crohn's Disease and Adenocarcinoma of the Right Colon: A Retrospective Cohort Study.

(1) Background: Crohn's disease (CD) and right-sided colorectal-carcinoma (CRC) are two common indications for right colectomies. Many studies have tried to identify risk factors associated with post-operative complications for both CD and CRC. However, data directly comparing the outcomes of the two are sparse. This study aims to compare the 30-day post-operative outcome after a right colectomy for CD versus CRC. Its secondary aim is to identify the factors associated with these outcomes for each group. (2) Methods: A retrospective cohort study of 123 patients who underwent a right colectomy for CD or CRC in a single institution between March 2011 and March 2016. (3) Results: There were no significant differences between the groups when comparing the overall complication rate, the median Clavien-Dindo score, reoperation rates and the length of hospitalization. The leak rate was higher in the Crohn's group (13.95% (6/43) vs. 3.75% (3/80)), p = 0.049), although the stoma rate was the same (4/43 9.5%; 7/80 9.9%). (4) Conclusions: This study has shown that post-operative complication rate is similar for right colectomy in CD and CRC. However, Crohn's disease patients did have a higher leak rate.

Performance study of the dynamic multi-leaf collimator system (DMLC-120)

BackgroundOur research focused on the design of the Dynamic Multi-Leaf Collimator (DMLC-120), which can be installed on the medical linear accelerator (KylinRay-MELAC). This innovative device, consisting of 60 leaf pairs, aims to significantly enhance the precision of radiation therapy. PurposeTo address the challenge of high leakage rates observed in traditional arc-end multi-leaf collimators upon leaf closure, we introduced a novel design that combines arc and flat end-face structures. This study evaluates the performance of this composite design, intending to establish a new standard for clinical dose modeling and planning systems, thereby improving the accuracy of radiotherapy delivery. MethodsBefore assessing performance, we conducted beam commissioning. Following established guidelines, we utilized an Electronic Portal Imaging Device (EPID) for assessing leaf positioning accuracy and reproducibility. The investigation of beam transmission, leakage, and the tongue and groove effect was facilitated through the use of EBT3 radiotherapy verification films and analysis with an EPSON EXPRESSION 12000XL scanner. Output factors, percent depth dose (PDD), and beam profiles were accurately determined using an IBA phantom equipped with an ionization chamber. ResultsThe composite end-face structure demonstrated exceptional performance, with leaf position accuracy and reproducibility deviations at 0.3 mm and 0.11 mm, respectively. Leakage through the leaves averaged at 0.98%, with a penumbra of 6.6 mm for a 10 × 10 cm2 field, indicating a significant improvement over traditional designs. ConclusionsThe innovative composite end-face structure for the arc-end MLC significantly mitigates the issue of high leakage rates during leaves closure. Our research demonstrated that all MLC performance levels were within the acceptable range based on the protocols, which were well below the specified tolerance limits, supporting highly accurate radiotherapy delivery.

Investigation of Partial Discharge Characteristics inside Vacuum Interrupter with Various Floating Shield Potentials

The reliable operation of vacuum circuit breakers (VCBs) plays an important role in the power system's reliability. The common cases which lead to the failure in the VCB are related to the loss of vacuum inside the vacuum interrupters (VIs). VIs commonly loses the vacuum with a higher leakage rate, resulting in a decrease in discharge voltage and partial discharge (PD) inside the VI which can lead to the eventual failure of the VCBs. Detecting vacuum leakage at the early stage became an important issue. In the prior study, vacuum failure was studied by detecting PD characteristics inside the VIs by regulating the different internal pressures. This study introduces a novel approach to investigating vacuum leakage within the VIs by detecting PD characteristics under various floating shield potentials to study the possibility of shield potential control on PD measurement. Comparing the experimental results measured at different internal pressures under various shield potentials, this study highlights the measurement of PD characteristics and the possibility of shield potential control on PD measurement. © 2024 Institute of Electrical Engineers of Japan and Wiley Periodicals LLC.

Intelligent UAV fire monitoring method based on improved YOLOv5 algorithm

Aiming at the existing UAV fire detection system with low small target detection accuracy, a high leakage rate, and a slow rate, an improved YOLOv5 UAV flame detection algorithm is proposed. First, the anchor box clustering is optimized using the K-mean++algorithm to reduce the classification error rate. Second, the original backbone network is enhanced with the CBAM attention mechanism, which scans the whole globe to obtain the target area with a high weighting proportion and needs to be focused on. Replace the PANet network with the BiFPN network in the neck and introduce jump connections when performing feature fusion, which can better retain the semantic information of high-level and low-level features. Finally, the α-IoU loss function is added to achieve the regression accuracy of different levels of the bounding box by modulating α, which improves the detection accuracy of small datasets and the robustness to noise. According to the experimental results, using a randomly segmented dataset, the modified YOLOv5 algorithm obtains a mAP value of 80.2%, which is 6.7% higher than the original YOLOv5 method, while maintaining an FPS of 64 frames per second. The method helps to improve the accuracy of UAVs for fire monitoring, and the performance is better than the existing flame detection algorithms, which meet the requirements of practical applications.

勺轮式排种器在振动条件下的排种性能试验研究

The seeder was tested and evaluated for field operations vibration characteristics in light of the issue that the spoon-wheel maize precision seeder vibrates due to the field operating conditions, which impairs the performance of the seed-metering device. During field testing, it was discovered that the seed-metering device vibrated greater as the forward speed increased, resulting in a higher peak vibration acceleration. However, fluctuations in forward speed did not affect the frequency distribution of the peak vibration acceleration. Time-domain and spectrogram investigations revealed that the vibration frequency of the seed-metering device was predominantly within 0~10 Hz for seeder operating speeds ranging from 2~6 km/h, with acceleration values spanning from 0.85~1.86 m/s2. An electromagnetic seeding test stand was established in response to the discoveries. The essential variables governing the seeding performance of the spoon-wheel seed-metering device were then investigated using orthogonal tests, such as forward speed, vibration frequency, and vibration acceleration. The empirical results elucidated a hierarchical relationship between these factors and seeding quality. Specifically, vibration frequency emerged to be the predominant factor, followed by vibration acceleration, and forward speed. The seeding quality of the seed-metering device was negatively correlated with increases in forward speed and vibration acceleration, which led to a lower qualified rate, higher leakage rate, and variation coefficient. Overall, the qualified rate, leakage rate, and variation coefficient were all significantly influenced by the three factors.

Synergistic enhancement of phase change materials through three-dimensional porous layered covalent triazine framework/expanded graphite composites for solar energy storage and beyond

The challenges of leakage and low thermal conductivity have emerged as obstacles that hinder the advancement of long-term thermal stability and versatility of phase change material (PCM). This study aims to address the challenges of high leakage rate and low thermal conductivity associated with paraffin wax (PW) in phase change energy storage. A composite PCM with a layered microstructure was successfully synthesized by physically blending expanded graphite (EG), covalent triazine framework (CTF), and adsorbed PW. For the first time, the encapsulation of (phase change materials) PCMs using covalent organic frameworks (COF) was realized. Subsequently, various aspects of the prepared materials were thoroughly characterized and analyzed, demonstrating excellent performance. The material exhibited a leakage rate of only 0.18 %, a thermal conductivity approximately 10 times higher than that of pure PW, and a high latent heat of phase change (111.26 J/g). After undergoing 500 thermal cycles of storage and release, the latent heat of phase change remained stable at around 72 %, indicating robust thermal cycle stability. Furthermore, photothermal tests revealed an impressive photothermal conversion efficiency of 86.9 % for the composite PCM, highlighting its remarkable photothermal conversion capability and efficiency. This study provides an innovative solution to the challenges of high leakage rate and low thermal conductivity in paraffin-based phase change energy storage. Additionally, it delivers valuable theoretical guidance and an experimental foundation for the development of more efficient and stablePCMs.