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Developing highly accurate sediment erosion testing methods for Pelton turbine overflow components is challenging due to their irregularly curved surfaces. In this study, we designed a method to evaluate the sediment erosion of the Pelton turbine bucket using test blocks with an accuracy of 0.0001 g. In addition, we conducted sediment erosion tests on a model Pelton turbine and conducted an in‐depth study on the installation design of the turbine runner and bucket, the design of the erosion test blocks, and the arrangement; we analyzed sediment abrasion distribution on the bucket's working surface. Our test results show that the bucket splitter edge, as well as the root of the working surface, are heavily worn. The maximum erosion rate of the working face is 0.7669 μm/h, and the maximum erosion rate of the splitter edge is close to 5 μm/h, which is highly consistent with the distribution of sediment erosion observed in Pelton turbines operating under sandy river conditions. This test method is essential for examining sediment erosion in Pelton turbines. [ABSTRACT FROM AUTHOR]

Individual carotenoids provide significant health benefits to humans, and potatoes are recognized as some of the most stable crops, distinguished by their substantial carotenoid content. To elucidate the accumulation patterns of individual carotenoids in potatoes, we quantified the carotenoid content in yellow- and white-fleshed genotypes across five developmental stages using LC-MS/MS. A total of 22 carotenoids were identified in yellow potatoes, whereas 18 were detected in white potatoes. The yellow-fleshed genotype was characterized by high levels of individual carotenoids and xanthophyll esters, with violaxanthin as the dominant component. The white-fleshed genotype exhibited low concentrations of individual carotenoids and xanthophyll esters, with lutein as the predominant compound. Notably, lutein, violaxanthin, zeaxanthin, antheraxanthin, neoxanthin, violaxanthin myristate, and lutein myristate were consistently detected during the developmental period in both genotypes. Violaxanthin myristate was identified as the dominant xanthophyll ester in both genotypes, showing an increasing trend throughout the tuber development stages. In contrast, xanthophyll esters maintained stable low levels in white-fleshed potatoes while exhibiting increasing types and contents in yellow-fleshed potatoes as the tubers continued to grow. Additionally, violaxanthin exhibited a significant correlation with b*, H°, and C*, suggesting that it may play an important role in forming yellow flesh. [ABSTRACT FROM AUTHOR]

Purple acid phosphatases (PAPs) are multifunctional proteins implicated in various aspects of plant biology, including flowering, seed development, senescence, carbon metabolism, and the response to biotic and abiotic stresses. Although PAPs have been reported in potatoes, the gene features and expression under phosphorus-solubilizing bacteria and freezing stresses remain unclear. In the present study, we identified 29 StPAPs with molecular weights ranging from 27.96 to 85.40 kDa, which were classified into three distinct groups based on a phylogenetic analysis. Integrating gene chromosomal localization, gene duplication events, intergenic collinearity, and gene selection pressure analysis, we found that the expansion of the potato PAP gene family was primarily driven by genome-wide duplication events, with the majority of the PAP genes undergoing purifying selection. Promoter cis-acting element analysis and RNA-Seq data revealed that a total of 89 cis-acting elements were associated with plant hormones, and the seven StPAP genes for low phosphorous response were associated with responses to abscisic acid, gibberellin, and abiotic stresses. Tissue expression pattern analyses indicated that the expression of StPAP genes were regulated in response to varying phosphorus levels. A co-expression network analysis identified eight StPAP genes involved in symbiosis with phosphorus-solubilizing bacteria, and seven StPAP genes exhibited significantly higher expression in response to freezing stress and abiotic stresses (drought, heat, darkness, and N/K/Ca/Fe/Mg/Zn deficiencies). In conclusion, the StPAP may synergistically modulate phytohormone levels in response to stress by regulating plant phosphorus homeostasis; StPAP12 and abscisic acid are key phosphorus-regulated genes and phytohormones in response to freezing stress. This study represents the first report to demonstrating the responsiveness of StPAPs to phytohormones, revealing a potential new function for these genes in plant stress responses and nutrient management. These findings provide novel insights into the multifaceted roles of PAPs in plant adaptation and stress tolerance. [ABSTRACT FROM AUTHOR]

The problem of sediment wear presents a significant challenge for hydraulic turbines operating in sediment‐rich rivers, particularly for high‐head Pelton turbines. In this study, the VOF model, SST k–ω model, and DPM model were employed to simulate the gas–liquid–solid three‐phase flow within a large Pelton turbine, which operates under a rated water head of 671 m and has a single capacity of 500 MW, at a hydropower station situated on a sediment‐laden river. The sediment wear prediction model, derived from the sediment wear test of the model turbine, was utilized to forecast the sediment wear on the flow components of the Pelton turbine at the hydropower station. The results show that there are obvious pressure and velocity gradients near the nozzle outlet of the Pelton turbine in the power station, and the wear of the nozzle surface is gradually increasing, and the wear in the downstream area of the nozzle is more serious. The wear rate at the needle tip surface reached 1.372 μm/h, while the socket ring surface exhibited a wear rate of 3.175 μm/h. he highest wear rate recorded for the water bucket is 0.940 μm/h. After a year of continuous operation, the maximum erosion observed was 5.62 mm on the runner bucket made of stainless steel and wear‐resistant metal, 8.23 mm on the spray needle, and 19.05 mm on the nozzle mouth ring, highlighting the severity of sediment wear on the Pelton turbine. It is recommended that surface treatment technology be applied to the flow‐through components of the Pelton turbine at this hydropower station to enhance the wear resistance of the turbine and extend the operational life of the unit. [ABSTRACT FROM AUTHOR]

Pelton turbines functioning in sandy river environments often encounter difficulties due to the swift movement of sediment particles, leading to erosion and damage to overflow components. These challenges can result in operational instability, particularly noticeable in large turbines. Pressure pulsation is crucial for turbine stability, and alterations in overflow component profiles caused by sediment erosion can worsen pressure pulsations. This study utilizes numerical simulations to analyze turbine pressure pulsations based on surface profile changes of runner buckets after 2 and 4 years of sediment erosion in a single 500 MW large‐scale Pelton turbine. Our findings reveal that erosion leads to a gradual decrease in pressure pulsation along the bucket's splitting edge from the notch to the root. After 4 years of erosion and wear, the relative pressure pulsation amplitude in the root region increased by more than 530%. Additionally, changes occur in the thickness of the water film in the erosion area on the working surface, disrupting the flow pattern and generating more vortices. This occurrence intensifies the relative pressure pulsation amplitude and reduces bucket stability. The study findings highlight the significant impact of sediment erosion on Pelton turbine pressure pulsation, posing a considerable risk to the unit's operational stability and safety. [ABSTRACT FROM AUTHOR]

Recently, Niche [J. Differential Equations, 260 (2016), 4440–4453] established upper bounds on the decay rates of solutions to the 3D incompressible Navier–Stokes–Voigt equations in terms of the decay character r ∗ of the initial data in H 1 (R 3). Motivated by this work, we focus on characterizing the large-time behavior of all space-time derivatives of the solutions for the 2D case and establish upper bounds and lower bounds on their decay rates by making use of the decay character and Fourier splitting methods. In particular, for the case − n 2 < r ∗ ⩽ 1 , we verify the optimality of the upper bounds, which is new to the best of our knowledge. Similar improved decay results are also true for the 3D case. [ABSTRACT FROM AUTHOR]

In this paper, we make the first attempt to figure out the differences on Hölder regularity in time of solutions and conserved physical quantities between the ideal electron magnetohydrodynamic equations concerning Hall term and the incompressible Euler equations involving convection term. It is shown that the regularity in time of magnetic field B is C_{t}^{\frac {\alpha }2} provided it belongs to L_{t}^{\infty } C_{x}^{\alpha } for any \alpha >0, its energy is C_{t}^{\frac {2\alpha }{2-\alpha }} as long as B belongs to L_{t}^{\infty } \dot {B}^{\alpha }_{3,\infty } for any 0<\alpha <1 and its magnetic helicity is C_{t}^{\frac {2\alpha +1}{2-\alpha }} supposing B belongs to L_{t}^{\infty } \dot {B}^{\alpha }_{3,\infty } for any 0<\alpha <\frac 12, which are quite different from the classical incompressible Euler equations. [ABSTRACT FROM AUTHOR]

In thermophotovoltaic (TPV) systems, it is crucial that the selective emitters can tailor emission spectrum to match the bandgap of photovoltaic (PV) cells and largely enhance the system efficiency. In this work, a metamaterial emitter based on the metal-insulator-metal (MIM) structure is proposed to obtain the high energy conversion efficiencies. The geometric parameters of MIM emitter have been investigated to obtain an excellent radiation spectrum of emitter composed of W and HfO2. The excellent emission performance of MIM emitter is attributed to the excitation of surface plasmon polariton (SPP) and cavity resonance, and the structure of MIM emitter is insensitive for different polarization modes. The 21 material combinations of MIM emitters have been screened to obtain the optimal emitter matching GaSb and InGaAsSb cells. This work identifies the crucial role of structure and materials into the emitter of a TPV system. In the evaluation of MIM emitter and TPV System, when the operating temperature of emitter increases from 1400 K to 2000 K, the system efficiency of optimal W/HfO2/W MIM emitter increases from 20.26% to 30.41%, while the output electric power increases from 3.59 kW/m2 to 42.48 kW/m2. The phenomenon indicates that the MIM emitter with the optimal material combinations and geometric parameters can significantly improve the matching degree with GaSb and InGaAsSb cells. Our results will be helpful to expand the optimization scope of metamaterial emitters in TPV systems. [ABSTRACT FROM AUTHOR]

In this study, FeMnCrNiBNbAl wear-resistant coatings were prepared via high-velocity arc spraying technology on the surface of Q235 steel. The effects of spraying distance, voltage, and current on the coating performance were studied via the orthogonal experimental method with microhardness and porosity as evaluation indicators, and the process parameters were optimized. The order of primary and secondary factors affecting coating performance were: spraying distance, voltage, and current. The optimized process parameters are: spraying distance 200 mm, voltage 36 V, and current 240 A. The coating prepared using the optimized process parameters has an average microhardness of 756 HV0.1 and an average porosity of 1.03%. The coating mainly consists of α-Fe, Fe-Cr, Ni-Cr-Fe, Al2O3, and (Fe, Ni) solid solution. The coating friction coefficient was 0.5 while that of the substrate was 0.7. The depth and width of the wear marks of the coating were 6.32 µm and 555.41 µm, respectively, which are 66% and 32% lower in comparison with Q235 steel under the same test conditions. The wear forms of this coating were mainly fatigue peeling and adhesive wear. [ABSTRACT FROM AUTHOR]

The outcomes of the best medical treatment (BMT) and intervention treatment (INT) in a single-center experience were reported in type B intramural hematoma (IMH). From February 2015 to February 2021, a total of 195 consecutive patients with type B IMH were enrolled in the study. The primary end point was mortality, and the secondary end points included clinical and imaging outcomes. The clinical outcomes were aortic-related death, retrograde type A aortic dissection, stent graft-induced new entry tear, endoleak, and reintervention. The imaging outcome was evaluated through the latest follow-up computed tomography angiography, which included aortic rupture, aortic dissection, aortic aneurysm, rapid growth of aortic diameter, newly developed or enlarged penetrating aortic ulcer or ulcer-like projection (ULP) and increased aortic wall thickness. Kaplan-Meier curves were used to assess the association between different treatments. Among the enrolled patients, 115 received BMT, and 80 received INT. There was no significant difference in early (1.7% vs 2.5%; P = 1.00) and midterm all-cause death (8.3% vs 5.2%; P =.42) between the BMT and INT groups. However, patients who underwent INT were at risk of procedure-related complications such as stent graft-induced new entry tear and endoleaks. The INT group was associated with a profound decrease in the risk of ULP, including newly developed ULP (4.3% vs 26.9%; P <.05), ULP enlargement (6.4% vs 31.3%; P <.05), and a lower proportion of high-risk ULP (10.9% vs 45.6%; P <.05). Although there was no significant difference in the incidence of IMH regression between the two groups, the maximum diameter of the descending aorta in patients receiving INT was larger compared with those treated with BMT. Based on our limited experience, patients with type B IMH treated with BMT or INT shared similar midterm clinical outcome. Patients who underwent INT may have a decreased risk of ULPs, but a higher risk of procedure-related events and patients on BMT should be closely monitored for ULP progression. [ABSTRACT FROM AUTHOR]

The lack of effective failure correlation analysis is one main reason for the gap between the reliability models and the actual complex systems with mixed static and dynamic characteristics. Takagi and Sugeno (T-S) dynamic fault tree is one powerful tool to analyze the static and dynamic failure logic relationship but it assumes the failure probability of the event is independent. Therefore, this paper proposes a multi-dimensional T-S dynamic fault tree analysis method involving failure correlation. The method integrates the failure probability distribution function of basic events with multi-factors and the multi-dimensional copula function, and the important measure of this method is also deduced. The reliability model expression for systems with failure correlations, both in series and in parallel, is discussed and verified. Compare the proposed method with the assumption that the probability of a failure event is independent. This method solves the problem of a large error when ignoring the failure correlation between parts and the degree of the correlation between variables can be characterized. The reliability analysis can be conducted on complex systems affected both by multi-factors and failure correlations. The proposed method is applied to the reliability analysis of a hydraulic height adjustment system and the correctness and superiority of the method are verified. [ABSTRACT FROM AUTHOR]