Research on the Construction Process of a Steel Truss Arch Bridge Based on BrIM

This paper combined BrIM (Bridge Information Modeling) technology with the bridge engineering to parameterize the information of a through type truss arch bridge, and BIM technology is used for information management and construction process management. Firstly, the information such as the size and material of each member of the truss arch bridge was input to the family library to construct the three-dimensional model corresponding to the plane and elevation information, which could be used for the drawing review. Then the Navisworks roaming model was used for collision check, the design development phase of the construction drawings were achieved to component geometry and the detailed tables in Revit was used to manage the materials. At last, TimeLiner in Navisworks was utilized to design the construction process so Navisworks could simulate the construction process. It is found that BrIM technology of Revit combined with Navisworks can effectively improve the communication efficiency of all side such as construction, supervision, design and construction, facilitate the industrial prefabrication of components, reduce the component collision before the construction phase, control the schedule of construction and optimize the construction process

Research on Vertical SEC Centrifugal Pump Multi-Fault Diagnosis Based on WPT–SVM

To diagnose common failures in vertical Essential Service Water Pumps (SEC), a method combining the wavelet packet transform (WPT) and the support vector machine (SVM) was adopted. This allowed us to construct a diagnostic model capable of classifying multiple states, including the six types of faults and normal conditions in SEC pumps. The diagnostic model utilized the wavelet packet coefficients to capture sub-bands with a higher energy share and reconstruct the signals. The model inputs the 12 frequency features into the support vector machine to analyze the vibration signals gathered from the SEC pump benchmark. The study illustrates that the proposed method can accurately differentiate between various fault conditions when compared to the WPT method, combined with the artificial neural network (ANN) approach. It attains a superior overall precision of up to 94%, and it displays excellent generalization and strong adaptability

Study on Flow Characteristics of a Single Blade Breakage Fault in a Centrifugal Pump

The precise identification of faults in centrifugal pumps is crucial for ensuring their safe and stable operation, given their significance as vital industrial equipment. This article aims to rigorously examine and analyze the flow characteristics of centrifugal pumps under two specific conditions: normal blade operation and a single blade breakage fault. Through systematic comparison and in-depth study, this article sheds light on distinguishing flow patterns exhibited by these pumps under both normal and fault scenarios. Utilizing validated numerical simulation methods, a thorough analysis is conducted to explore the flow condition and energy characteristics of the impeller channel following the breakage of a single blade. Additionally, the article investigates changes in the pressure pulsation characteristics of the pump volute as a result. The numerical simulation results reveal that the head of the centrifugal pump decreases at all flow points when a single blade breaks. However, there is no significant change in efficiency at small flow points. As the flow rate exceeds 0.9Qd, efficiency experiences a substantial decrease. Furthermore, the efficiency decline becomes even more pronounced as the flow rate continues to increase. At 1.5Qd, efficiency plummets by 14.33%. The flow pattern undergoes significant changes as well. The breakage of the blade induces noteworthy secondary flow in adjacent impeller channels, resulting in heightened turbulence dissipation. Additionally, it was observed that blade fracture causes alterations in the main frequency of pressure pulsation within the volute. This is characterized by an increase in shaft passing frequency and a decrease in blade passing frequency. Notably, near the tongue monitoring point, the shaft frequency escalates by over 20 times

Metabolites of Hypoxic Cardiomyocytes Induce the Migration of Cardiac Fibroblasts

Background: The migration of cardiac fibroblasts to the infarct region plays a major role in the repair process after myocardial necrosis or damage. However, few studies investigated whether early hypoxia in cardiomyocytes induces the migration of cardiac fibroblasts. The purpose of this study was to assess the role of metabolites of early hypoxic cardiomyocytes in the induction of cardiac fibroblast migration. Methods: Neonatal rat heart tissue was digested with a mixture of trypsin and collagenase at an appropriate ratio. Cardiomyocytes and cardiac fibroblasts were cultured via differential adhesion. The cardiomyocyte cultures were subjected to hypoxia for 2, 4, 6, 8, 10, and 12 h. The supernatants of the cardiomyocyte cultures were collected to determine the differences in cardiac fibroblast migration induced by hypoxic cardiomyocyte metabolites at various time points using a Transwell apparatus. Meanwhile, ELISA was performed to measure TNF-α, IL-1β and TGF-β expression levels in the cardiomyocyte metabolites at various time points. Results: The metabolites of hypoxic cardiomyocytes significantly induced the migration of cardiac fibroblasts. The induction of cardiac fibroblast migration was significantly enhanced by cardiomyocyte metabolites in comparison to the control after 2, 4, and 6 h of hypoxia, and the effect was most significant after 2 h. The expression levels of TNF-α, IL-1β, IL-6, and TGF-β were substantially increased in the metabolites of cardiomyocytes, and neutralization with anti-TNF-α and anti-IL-1β antibodies markedly reduced the induction of cardiac fibroblast migration by the metabolites of hypoxic cardiomyocytes. Conclusion: The metabolites of early hypoxic cardiomyocytes can induce the migration of cardiac fibroblasts, and TNF-α and IL-1β may act as the initial chemotactic inducers

Control and Application of Terrain Curvature on Dynamic Disasters: A Case Study of Coal and Gas Outbursts in the Pingdingshan Mining Area, China

Based on coal and gas outburst mining area topography, a risk evaluation index for mine dynamic disasters in relation to terrain curvature is presented by analyzing the terrain curvature formation and determining its classification and computational methods. Clarifying the mechanism that the terrain curvature changes reflects the intensity of tectonic activity and the tectonic stress field variation, as well as coal and rock mass energy storing. By using the N-shaped landform in the Pingdingshan coal mine as a case study, an area having strong tectonic activity and coal and gas outbursts was recorded to occur where terrain curvature changed, notably occurring where the positive curvature radius was 80.21% of the total. These findings indicate that terrain curvature has significant controlling effects on coal and gas outbursts. A preliminary assessment for the occurrence risk of coal and gas outbursts using the terrain curvature value is proposed which can be used as an effective method to predict future outbursts

Loading and Sustained Release of Benzyl Ammonium Chloride (BAC) in Nano-Clays

Benzyl ammonium chloride (BAC) is a broad-spectrum bactericide, but vulnerable to leaching by water. In this paper, halloysite nanotubes (HNT) and montmorillonite (MMT) were used as drug carriers to load BAC, in order to achieve good anti-mildew activity and long-term sustained release properties. The HNT and MMT nano-composites were characterized by transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and nitrogen adsorption/desorption. XRD results showed that BAC intercalated the interlayer of MMT, and expanded the interlayer spacing from 1.15 nm to 1.75 nm. Pore analysis showed that BAC decreased the cavity of halloysite nanotubes to a certain extent, which indicated that BAC loaded inside the lumen of HNT successfully. TG analysis showed that the loading capacity of MMT to BAC was higher than HNT. The accelerated-release experiments revealed both two clays have significant sustained-release effects on BAC, and the releasing rate of HNT was relatively lower. Both HNT and MMT have promising application prospects as sustained-release carriers. The inhibition test showed that BAC in nano-clay has good anti-mildew resistance performance