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As the grid impedance increases, the grid strength gradually becomes weak. In order to have good output characteristics in weak grid, grid-forming (GFM) inverters with LCL filter have gradually become popular. This paper studies grid-current-sensorless control which does not require grid current sensors. Firstly, the grid-current-sensorless control loops are given. Then, in order to make up for the inability to sample the actual grid current, a grid current estimator, which is derivative operator free and low-complexity, is proposed. And the robustness and accuracy of the estimator is verified by simulation. Afterwards, to demonstrate that this control operates stably when the grid strength changes, a joint small-signal stability analysis combining the control strategy and circuit topology is presented. The theoretical feasibility of the control is proved. Finally, to verify the robustness of the control under different grid strengths, the experiments are carried out on a 20kW GFM inverter. The results show that the proposed control has satisfactory steady-state and dynamic performance whether under strong grid or weak grid. • The proposed method is suitable for both strong and weak grids. • The proposed current estimator has low complexity. • The proposed method reduces the use of sensors and reduces the hardware cost. [ABSTRACT FROM AUTHOR]

The research on the control mechanism of a covering layer on self-noise of the interior hull field remains underdeveloped. Because the detection function of sonar is greatly affected by the self-noise of the platform area, the sonar dome of composite material exhibits significant self-noise suppression while ensuring sufficient sound penetration. Based on an infinite flat model of a point-force excitation combined with a simplified two-degree-of-freedom system coupled with shell and flexible composite covering layer, the structure of the shell plate with or without a covering layer is analysed, and the expressions for the insertion loss and the degree of isolation of the covering layer in response to the shell vibration are deduced according to mechanical properties. In addition, this paper presents an influence law of a covering layer on the shell system vibration response under different stiffness, mass and damping parameters when the load is on a shell plate or covering layer. The most important contributions of this paper are the interior noise and vibration performance tests of a typical local carbon/glass hybrid reinforced sheet-beam structure with or without an overlying rubber blanket, where the layered material is on the interior of the structure. The experiment was implemented in air. The test model, filled with water, was hung by a flexible rubber band. In addition, the comparison of the structural vibration suppression and noise reduction performance of covering layers was made under different load types. [ABSTRACT FROM AUTHOR]

Silt is a common waste soil that is often treated by solidification with ordinary Portland cement (OPC). Geopolymer is a cementitious material formed by the polycondensation reaction of fly ash and other industrial waste materials in a non-high-temperature environment under alkali excitation. This study used fly ash-based geopolymer to partially replace OPC in silt solidification to reduce the use of OPC. The investigated replacement ratios of geopolymer for OPC were selected as 0% (control group), 5%, 10%, and 15%, and the water contents were selected as 28%, 30% (liquid limit of 29.6%), 32%, and 34%, respectively. To investigate the influence of curing time (7, 14, 28, and 60 d) on the mechanical properties of solidified silt, unconfined compressive strength tests and stress-strain curve study were conducted. To better understand how geopolymer and cement behave during the solidification of silt, scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, and mercury intrusion porosimetry were used to evaluate the morphology, elemental composition, mineral composition, and pore distribution of the solidified soils. The experimental results show that the silt solidified with geopolymer-cement had good performance. Under the same water content, as the proportion of cement replaced by geopolymer increased, the compressive strength of the solidified soil first increased and then decreased. When the silt had a water content of 30% and a curing period of 28 d, the strength of the solidified soil increased significantly (approximately 13.17%-51.42%). Microstructural analysis showed that more cementitious materials were produced in the soil solidified with geopolymer-cement. The geopolymer-cement wrapped around the soil particles and filled the voids, resulting in increased soil compactness and thus improving the silt strength. • Fly ash-based geopolymer partially replaces OPC to reduce the use of OPC. • The mechanical properties of solidified silt were studied, UCS test were conducted. • More cementitious materials are produced in solidified silt by geopolymer-cement. • It is beneficial to the reasonable application of fly ash in geopolymer field. [ABSTRACT FROM AUTHOR]

Glucose is a fundamental substance for numerous cancers, including glioma. However, its influence on tumor cells regulatory mechanisms remains uncertain. SIRT1 is a regulator of deacetylation and a key player in the progression of malignant tumors. The objective of this study was to examine the role of glucose and SIRT1 in glioma. This study investigated the association of SIRT1 expression with clinicopathological features and prognosis in glioma patients using the TCGA database. The Western blotting technique was used to identify the expression of SIRT1 protein in glioma cells. The study also examined the impact of differing glucose concentrations on the biological functions of glioma cells. The study investigated the expression of SIRT1 and HMGB1 signaling pathways in glioma. Additionally, resilience experiments were conducted utilizing SRT1720. SIRT1 is a gene that suppresses tumors and is low expressed in gliomas. Low expression of this gene is strongly linked to a poor prognosis in patients with glioma. High concentrations of glucose can promote the proliferation, migration, and invasion of glioma cells, while also inhibiting apoptosis. The findings of this mechanistic study provide evidence that glucose can down-regulate SIRT1 expression, leading to increased levels of acetylated HMGB1. This in turn promotes the ex-nuclear activation of HMGB1 and associated signaling pathways, ultimately driving glioma malignancy. Glucose has the ability to regulate the HMGB1 associated signaling pathway through SIRT1, thus promoting glioma progression. This holds significant research value. • High glucose promotes malignant progression of gliomas and decreases SIRT1 expression. • Activation of SIRT1 inhibits the HMGB1 signaling pathway。 • Glucose promotes glioma progression through SIRT1 regulation of HMGB1 related signaling pathway. [ABSTRACT FROM AUTHOR]

Accurate prediction of the average thermal extraction load (ATEL) in hydrothermal heating systems optimizes energy recovery, though numerical models are constrained by modeling accuracy and computational time costs. Data-driven modeling can efficiently screen alternative production plans and enhance daily operational decisions. However, ensemble learning applications for forecasting ATEL lack comprehensive comparisons and appropriate algorithm selection. This study evaluates six ensemble learning algorithms: random forest (RF), adaptive boosting (AdaBoost), gradient boosting decision trees (GBDT), extreme gradient boosting (XGBoost), light gradient boosting machine (LightBGM) and categorical boosting (CatBoost) on 1159 data points from a homogeneous thermal-hydraulic coupling numerical model. The superior performance of the CatBoost is characterized by the highest accuracy (with the lowest root mean square error (RMSE) of 150.6 kW–170.7 kW, minimal mean absolute percentage error (MAPE) of 0.66%–0.73%, and exceptional R2 values of 0.999), commendable stability, reasonable computational cost and low uncertainty. LightGBM, XGBoost, and GBDT are identified as suitable substitutes, whereas RF is a possible substitute. Moreover, the production rate is identified as the most significant factor contributing to the ATEL, followed by the well spacing and injection temperature. While perforation depth has the least influence on heat recovery. • Comprehensive evaluation of six ensemble learning applications in ATEL prediction. • CatBoost achieves superior accuracy, stability, computational efficiency and minimal uncertainty. • Incorporating sensitivity analysis and empirical knowledge emphasizes feature importance. [ABSTRACT FROM AUTHOR]