The Alteration of Runner and Partial Vanes on a Fixed Blade Propeller Water Turbine Basing on the Full Passage Simulation

ABSTRACT Basing on the 3D-steady Navier-Stokes equations with standard k-ε turbulence closure models, non-structure mesh with fitted body coordinate and finite element based finite volume method, the internal flow on the full passage of the 6.5-meters head fixed blade propeller water turbine is analyzed. Numerical results show that the low output is caused by unsuitable full passage. The flow on the stay vanes isn't uniform and the circumferential velocity of the runner rim is too large, which leads to a high loss in the draft tube. So the runner and partial stay vanes in the concrete spiral casing are redesigned. The output of the full passage with new runner and new partial stay vanes under 6.5-meters head is 295KW larger than the old one with 240KW output, and the efficiency is 81%, which is larger than former 70%. The redesign of runner and stay vanes is successful

Curcumin exhibits therapeutic effect against spinal cord injury via inhibition of neuronal inflammation and apoptosis

Purpose: To investigate the effect of curcumin on spinal cord injury (SCI) in a rat model. Methods: SCI was induced in the rats using mid thoracic spinal cord compression, after which curcumin was injected intraperitoneally. Western blotting was used for assay of expressions of apoptotic proteins, viz, IL-1β, NF-κB p65, TLR4, TNF-α, LC3, Bax and Bcl-2. Malondialdehyde (MDA) and myeloperoxidase were measured using standard methods. Neuronal loss in spinal cord tissues was determined with TUNEL staining and NeuN labelling. Results: Curcumin treatment significantly (p < 0.05) suppressed SCI-mediated upregulation of myeloperoxidase activity and increase in MDA level in rat spinal cord. The reduction of glutathione (GSH) and superoxide dismutase (SOD) activities in the spinal cord of SCI rats were suppressed by curcumin treatment. Curcumin treatment also led to a significant (p < 0.02) increase in the proportion of NeuN positive cells and marked reduction in TUNEL positive cells, but it decreased caspase-3 in the spinal cord tissues of SCI rats. Moreover, curcumin reversed the effect of SCI on protein expressions of Bax and Bcl 2 in a dose-based manner. There was marked curcumin-induced decline in CD11b and GFAP levels in the spinal cord tissues of the SCI rats. Conclusion: These results demonstrate that curcumin protects rats against SCI via inhibition of oxidative stress-mediated neuronal apoptosis. Therefore, curcumin may be useful for the development of an effective treatment for spinal cord injury

Wood fracture pattern during the water desorption process

Wood is a hygroscopic material and its mechanical properties change with moisture content below the fiber saturation point. Fracture characteristic is one of most important mechanical properties of wood and often is taken as an important safety design factor for wood as an engineered structural material. The aim of this paper is to investigate the effect of moisture content changes on wood fracture properties, focusing on fracture behavior and patterns with different crack orientations of Betula platyphylla Suk. and Pinus bungeana in two different desorption processes. These two desorption processes were, respectively, from fiber saturation point to an equilibrium moisture content corresponding to 82.4%RH at 20ºC and from 82.4%RH to 35.2%RH at the same temperature of 20ºC

New Particle Formation in the Remote Marine Boundary Layer

Marine low clouds play an important role in the climate system, and their properties are sensitive to cloud condensation nuclei concentrations. While new particle formation represents a major source of cloud condensation nuclei globally, the prevailing view is that new particle formation rarely occurs in remote marine boundary layer over open oceans. Here we present evidence of the regular and frequent occurrence of new particle formation in the upper part of remote marine boundary layer following cold front passages. The new particle formation is facilitated by a combination of efficient removal of existing particles by precipitation, cold air temperatures, vertical transport of reactive gases from the ocean surface, and high actinic fluxes in a broken cloud field. The newly formed particles subsequently grow and contribute substantially to cloud condensation nuclei in the remote marine boundary layer and thereby impact marine low clouds

Maximum likelihood estimation-assisted ASVSF through state covariance-based 2D SLAM algorithm

The smooth variable structure filter (ASVSF) has been relatively considered as a new robust predictor-corrector method for estimating the state. In order to effectively utilize it, an SVSF requires the accurate system model, and exact prior knowledge includes both the process and measurement noise statistic. Unfortunately, the system model is always inaccurate because of some considerations avoided at the beginning. Moreover, the small addictive noises are partially known or even unknown. Of course, this limitation can degrade the performance of SVSF or also lead to divergence condition. For this reason, it is proposed through this paper an adaptive smooth variable structure filter (ASVSF) by conditioning the probability density function of a measurementto the unknown parameters at one iteration. This proposed method is assumed to accomplish the localization and direct point-based observation task of a wheeled mobile robot, TurtleBot2. Finally, by realistically simulating it and comparing to a conventional method, the proposed method has been showing a better accuracy and stability in term of root mean square error (RMSE) of the estimated map coordinate (EMC) and estimated path coordinate (EPC)

Study on Small Layers Producing Condition by Using the Method of Fuzzy Comprehensive Evaluation

Before the subdivision adjustment of single well layers carried out, we need to evaluate the producing degree of the existing layers. There are many factors affecting the properties of small layers. This paper, using fuzzy comprehensive evaluation method, calculates the comprehensive evaluation coefficient to judge the property of each small layer

Human impacts on the cladoceran community of Jili Lake, arid NW China, over the past century

Deterioration of aquatic ecosystems, as a consequence of human-induced disturbances, is a critical global concern. To fully understand the responses of aquatic systems to anthropogenic impacts, it is crucial to assess long-term changes in lakes. The water quality of Jili Lake, a large water body in northwest China, has deteriorated recently, owing to the growing impacts of regional warming and human activities. Thus, Jili Lake was a prime candidate for evaluation of historical multi-stressor impacts. Meteorological data, historical documents, and assemblages of cladoceran microfossils in the sediments of Jili Lake were employed to investigate changes in the cladoceran community over the past century, and to evaluate the response of that aquatic community to human activities. From the 1920s to the 1950s, species richness of the cladoceran community was high, which reflected conditions of relatively low human impact. From the 1960s to 1970s, a sharp decrease in Bosmina longirostris, a planktonic cladoceran species, suggested a decrease in water level as a result of dam construction and intensified water exploitation. Since the 1980s, the water level in the lake has been restored, but increased fish farming and construction of a water storage facility caused salinisation and eutrophication of Jili Lake. Accordingly, the cladoceran community displayed distinct signs of a regime shift, with a gradual transition to dominance of B. longirostris and a sharp decrease in littoral species (e.g. Leydigia leydigi, L. acanthocercoides, Alona quadrangularis, Alona affinis). Our results suggest that human-induced disturbances were the main factor that drove changes in the cladoceran community since about the mid-20th century.Peer reviewe

More income, less depression? Revisiting the nonlinear and heterogeneous relationship between income and mental health

This paper uses a large-scale nationally representative dataset to examine the nonlinear effect of income on mental health. To investigate their causal relationship, the exogenous impact of automation on income is utilized as the instrument variable (IV). In addition, to explore their nonlinear relationship, both income and its quadratic term are included in regressions. It is found that the impact of income on mental health is U-shaped rather than linear. The turning point (7.698) of this nonlinear relation is near the midpoint of the income interval ([0, 16.113]). This suggests that depression declines as income increases at the lower-income level. However, beyond middle income, further increases in income take pronounced mental health costs, leading to a positive relationship between the two factors. We further exclude the possibility of more complex nonlinear relationships by testing higher order terms of income. In addition, robustness checks, using other instrument variables and mental health indicators, different IV models and placebo analysis, all support above conclusions. Heterogeneity analysis demonstrates that males, older workers, ethnic minorities and those with lower health and socioeconomic status experience higher levels of depression. Highly educated and urban residents suffer from greater mental disorders after the turning point. Religious believers and Communist Party of China members are mentally healthier at lower income levels, meaning that religious and political beliefs moderate the relationship between income and mental health