337 research outputs found

    Numerical investigation of breaking wave loads on the downstream inclined cylinder under shelter effect from the upstream vertical cylinder

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    Breaking waves interaction with two tandem cylinders are numerically studied using Computational Fluid Dynamic (CFD) software OpenFOAM. The effects of transverse inclined angles of the downstream cylinder and separation distances between two cylinders on breaking wave loads and free surface elevations are investigated. The interface between air and water phases is captured by the Volume of Fluid (VOF) method. The Shear Stress Transport k − v(SST k − v) turbulence model is employed to solve the incompressible Reynolds-Averaged Navier-Stokes (RANS) equations. The present numerical model is validated against published experimental data by examining the horizontal breaking wave loads and free surface elevations of breaking waves past a vertical cylinder and an inclined cylinder. In the present incident wave conditions, the breaking wave force on the downstream cylinder decreases first and then increases with the transverse inclined angle varying from 0o to 30o, while it shows an opposite trend versus the distance between cylinders. The maximum breaking wave load on the downstream cylinder occurs when the it is installed vertically with a separation distance of four times diameter.publishedVersio

    Effects of pH on phosphorus form transformation in lake sediments

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    The pH value of lake water varies with the lake environment, which has an effect on the form of phosphorus in sediment, and then the release of sediment phosphorus. The form of phosphorus in sediments was analyzed using field sampling. The environmental conditions with pH values of 4.0, 7.0 and 10.0 were simulated indoors to estimate the effects of pH on phosphorus release from sediments and the content change of various forms of phosphorus was studied. The results showed that in Wuliangsuhai Lake, Ca-P accounted for 54.3%, which was the largest portion of the TP. Phosphorus release was favored under acidic and alkaline conditions, and the alkaline condition was more favorable. The proportion of Fe/Mn-P and Fe/Al-P in the TP decreased with an increase in the pH, while the proportion of Ca-P in the TP increased with an increase in the pH. Under the alkaline condition (pH = 10), Ca-P in the sediment increased significantly, with an increase of 22.5%. However, Fe/Mn-P and Fe/Al-P decreased significantly, with drops of 37.3% and44.9%, respectively. Under the acidic condition (pH = 4), Fe/Mn-P and Fe/Al-P in the sediment increased significantly, and the increases were 63.1% and 37.1%, respectively. However, Ca-P decreased significantly, with a drop of 39.2%. In general, low pH promoted the release of Ca-P, and a high pH promoted the release of Fe/Mn-P and Fe/Al-P. Wuliangsuhai Lake water is characterized by weak alkaline characteristics throughout the year, and biological available phosphorus accounts for 13.3%-20.9% of the TP, with Fe/Mn-P being the dominant form. This study revealed that the risk of phosphorus release from sediments to the overlying water was greater under alkaline conditions.Peer reviewe

    Electrochemical Performances of Li+ Intercalation and Deintercalation Processes for Electrochromism of MoO3-Doped V2o5 Films Prepared By The Sol-Gel Method

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    MoO3-doped V2O5 thin films electrode exhibit much enhanced electrochemical performances than the pure V2O5 counterpart. 1M nonaqueous solution of LiClO4 in propylene carbonate (PC) was the electrolyte solution about cyclic voltammetry (CV) of V2O5/MoO3/ITO glass electrodes at room temperature. With the increasing proportion of MoO3 doped in V2O5, all the redox peak currents of the five samples increased, suggesting that their electrochemical activity increased with the initial CV cycles. Disappearing of some phase transition peaks also show that the MoO3-doped V2O5 film makes cyclic stability declining. Compared with the switching speed of films, the coloring and the bleaching times of the MoO3-doped V2O5 thin films are shorter

    Effects of Saline and Alkaline Stresses on Growth and Physiological Changes in Oat (Avena sativa L.) Seedlings

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    Two neutral salts (NaCl and Na2SO4) and alkaline salts (NaHCO3 and Na2CO3) were both mixed in 2:1 ratio, and the effects of saline and alkaline stresses on growth and physiological changes in oat seedlings were explored. The result showed that biomass, water content and chlorophyll content decreased while cell membrane permeability significantly increased under alkaline stress. Saline stress did not have an obvious effect on pH value in tissue fluids of shoot and root, but alkaline stress increased pH value in the root tissue fluid. The contents of Na+, Na+/K+, SO42- increased more, and K+, NO3-, H2PO4- decreased more under alkaline stress, the Cl- content increased obviously under saline stress but had little change under alkaline stress. The increments of proline and organic acid were both greater under alkaline stress, but organic acid content kept the same level under saline stress. Alkaline stress caused more harmful effects on growth and physiological changes in oat seedlings especially broke the pH stability in the root tissue fluid. Physiological adaptive mechanisms of oat seedlings under saline stress and alkaline stress were different, which mainly took the way of accumulating organic acid under alkali stress but accumulating Cl- under saline stress

    Water Balance Analysis of Hulun Lake, a Semi-Arid UNESCO Wetland, Using Multi-Source Data

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    Hulun Lake is the largest lake in northeastern China, and its basin is located in China and Mongolia. This research aims to analyze the dynamic changes in the water volume of Hulun Lake and to estimate the groundwater recharge of the lake during the past 60 years. Multi-source data were used, and water-level-data-interpolation extrapolation, water-balance equations, and other methods were applied. The proportion of the contribution of each component to the quantity of water in Hulun Lake during the last 60 years was accurately calculated. Evaporation loss was the main component in the water loss in Hulun Lake. In the last 60 years, the average annual runoff into the lake was about 1.202 billion m3, and it was the factor with the largest variation range and the leading factor affecting the changes in the quantity of water in Hulun Lake. There was groundwater recharge in Hulun Lake for a long period, and the average annual groundwater recharge was about 776 million m3 (excluding leakage). The contribution ratio of the river water, groundwater, and precipitation to the recharging of Hulun Lake was about 5:3:2. The changes in the quantity of water in Hulun Lake are affected by climate change and human activities in China and Mongolia, especially those in Mongolia

    Effects of different cooling methods on the carbon footprint of cooked rice

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    peer-reviewedGlobal warming has become a serious problem facing the international community. All countries strive to reduce greenhouse gas (GHG) emissions. The food system produces a large amount of GHGs, and thus study of the carbon footprint (CF) in the food industry has attracted the attention of researchers. Based on the lifecycle assessment (LCA) method, the present study calculated CFs of cooling of cooked rice, as a unit operation under different operational conditions. The results showed that the carbon footprints for cooling 200 g cooked rice were 54.36 ± 1.07 gCO2eq for refrigerator cooling at 0 °C, 66.05 ± 2.00 g CO2eq for refrigerator cooling at 8 °C, 741.55 ± 27.26 g CO2eq for vacuum cooling, 1914.10 ± 141.24 g CO2eq for air blast cooling at 0 °C, 2463.61 ± 221.21 g CO2eq for air blast cooling at 3 °C, and 3916.54 ± 202.28 g CO2eq for air blast cooling at 8 °C. In addition, the CF for the cooling process was positively correlated with the output power of equipment and the cooling time. The carbon emissions arising from electricity consumption contributed to most of the CF for the cooling process. Sensitivity analysis of the parameters for the CF for the cooling process revealed that the CF of cooling process was stable for the applied equipment emission factor, but sensitive to the efficiency of electricity use and the extent of load. Improving the efficiency of electricity use and increasing cooling load could reduce the final CF of a product

    Construction of urban wetland ecological landscape planning model based on MSPA analysis method

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    The traditional method does not accurately select the ecological landscape pattern index of urban wetland, which leads to the problems of low accuracy and long planning time, in order to solve this problem, an urban wetland ecological landscape planning model based on MSPA analysis method is constructed. By analyzing the basic components of urban wetland ecological landscape, such as patch density, aggregation index, dispersion index, average fractal dimension, landscape segmentation, shape index, spread index and Shannon diversity index, MSPA analysis method is used to extract the core area, patch area and ring of urban wetland. According to the extraction results, the minimum function of cloud fusion transformation of three-dimensional wetland ecological landscape is calculated, and the function is used to calculate the three-dimensional translation transformation amount and rotation matrix of three-dimensional wetland ecological landscape model. The data in the three-dimensional model are used for wetland ecological landscape planning, so as to complete the construction of wetland ecological landscape planning model. The simulation results show that the urban wetland ecological landscape planning accuracy of the model is high and the planning time is short

    Asexual reproduction strategies in the moon jellyfish Aurelia (Cnidaria: Scyphozoa)

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    The genus Aurelia is one of the major contributors to jellyfish blooms in coastal waters, possibly due to its adaptive reproduction strategies. Different Aurelia lineages have adapted their reproduction modes to varying environmental conditions in their respective habitats. To understand the successful adaptation strategies, three strains of Aurelia coerulea and two strains of Aurelia solida polyps from different geographical areas were exposed to a range of temperatures and two food regimes, and the effects on reproduction rates were assessed. Asexual reproduction was significantly affected by the changes in these factors. The highest reproduction rate under sufficient food conditions was observed in the United States strain and the lowest was observed in the Israel strain, regardless of temperature, indicating the differences in the blooming potential. Six asexual reproduction modes were observed, of which lateral budding, lateral budding by means of stolons, and reproduction from parts of stolons were the main modes used by all Aurelia strains, except Aurelia solidaISR, for which reproduction by stolons was the main mode. The capability to switch reproductive strategies in response to environmental cues depending on the lineage predetermines the highly frequent blooming events of Aurelia.Fil: Wang, Fanghan. Chinese Academy of Sciences; República de ChinaFil: Schiariti, Agustin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina. Instituto Nacional de Investigaciones y Desarrollo Pesquero; ArgentinaFil: Xu, Shengnan. Chinese Academy of Sciences; República de ChinaFil: Ma, Yuanqing. Shandong Marine Resource And Environment Research Institute; ChinaFil: Sun, Tingting. Chinese Academy of Sciences; República de ChinaFil: Wang, Lei. Chinese Academy of Sciences; República de ChinaFil: Zhao, Jianmin. Chinese Academy of Sciences; República de ChinaFil: Dong, Zhijun. Chinese Academy of Sciences; República de Chin
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