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Open access

Liupeng Jiang, Tao Tao, Cheng Zhang, He Jiang and Jiaojiao Wang

Abstract

Port shoreline resources are the basis of port and shipping development, and its assessment method has become one of the hot issues in port research. On the basis of constructing a reasonable index evaluation system, this paper constructs the fuzzy evaluation matrix based on the triangular fuzzy analytic hierarchy process and constructs the fuzzy evaluation matrix by using the fuzzy comprehensive evaluation method, and obtains the maximum membership degree of the port shoreline resources. Compared with the traditional port shoreline Resource evaluation methods, the new one got more advantages in objective and quantitative. Finally, Combined with the Nanjing section of the Yangtze River as a case for verification, the results show that the model can accurately solve the problem of resource evaluation of port shoreline.

Open access

Songfa Zhang, Shan Jiang and Xiao Zang

Open access

Zhang Zhiyang, Ma Yong, Jiang Jin, Liu Weixing and Ma Qingwei

Abstract

Vertical-axial tidal current turbine is the key for the energy converter, which has the advantages of simple structure, adaptability to flow and uncomplex convection device. It has become the hot point for research and application recently. At present, the study on the hydrodynamic performance of vertical-axial tidal current turbine is almost on 2-D numerical simulation, without the consideration of 3-D effect. CFD (Computational Fluid Dynamics) method and blade optimal control technique are used to improve accuracy in the prediction of tidal current turbine hydrodynamic performance. Numerical simulation of vertical-axial tidal current turbine is validated. Fixed and variable deflection angle turbine are comparatively studied to analysis the influence of 3-D effect and the character of fluid field and pressure field. The method, put the plate on the end of blade, of reduce the energy loss caused by 3-D effect is proposed. The 3-D CFD numerical model of vertical-axial tidal current turbine hydrodynamic performance in this study may provide theoretical, methodical and technical reference for the optimal design of turbine.

Open access

Jiliang Zhang, Hong Jiang and Gaofeng Pan

Abstract

In Rician-fading scenario, cognitive radio networks (CRNs) with a source in a secondary system transmitting its confidential information to a legitimate destination in the presence of an eavesdropper, are considered in this paper. Under CRNs, the interference power reaching at primary user (PU) is limited by some pre-defined threshold. Secrecy outage not only occurs when the achievable secrecy capacity for source-destination link is smaller than a target rate, but also occurs in the case that the interference power at PU is greater than that threshold. Analytical expression for secrecy outage probability has been derived and verified with simulation results. In addition, we have also derived the analytical expression for probability of non-zero secrecy capacity.

Open access

Jiang Hongxia, Liu Jihong, Chai Zhilei, Wang Chunxia and Zhang Mingxia

Abstract

In this paper, a novel classification method of assessing garment sewing stitch based on amended bi-dimensional empirical mode decomposition (ABEMD) has been introduced. Two parameters that characterise garment sewing stitch, average area and standard deviation, have been defined based on the grey value of pixels. Experimental results showed that when the window size is 512×128 pixels with regard to average area, the threshold can be decided as 6.00, 5.50, 5.30 and 4.00 for five different grades , respectively. Meanwhile, with regard to standard deviation, the threshold can be decided as 48.00, 40.00, 30.00 and 20.00, respectively. It is demonstrated that the parameters are effective in discriminating sewing stitch images in terms of the grades when used as inputs for the ABEMD. The performance of the algorithm on different garment status is significantly reliable.

Open access

X. Zhang, W. Liang, D. Jiang, Z. Liu and S. Jiang

Abstract

Soil nematode community structure was studied in a terrestrial sand dune system of the Horqin Sandy Land, Northeast China. The nematode abundance and generic composition in four sites (from the lowland, the middle part of windward slope and the top of windward slope to leeward slope) and three soil layers (0–20 cm, 20–40 cm and 40–60 cm) of the stabilized sand dune were compared. The results showed the total number of nematodes which ranged from 11 to 160 individuals per 100 g dry soils was significantly different among the sites and the depths (P < 0.05). Thirty genera were observed and Acrobeles was the dominant genus in our investigation. A significant difference in the abundance of bacterivores was found among the depths (P < 0.01). The total numbers of nematodes and plant parasites positively correlated with electronic conductivity, soil moisture, total organic carbon and nitrogen contents (P < 0.05). S, TD, NCR and PPI were found to be sensitive to environmental stress in the stabilized sand dune system.

Open access

Zhenyu Jiang, Min Xiang, Mingdong Lin, Weihua Zhang and Shuai Zhang

ABSTRACT

Annular cavitator with water injection is one of the key parts of the long-range supercavitating vehicle powered by water ramjet. In this paper, hydrodynamic properties of annular cavitator are studied numerically. The standard k ~ ε turbulence model is coupled with the Reynolds Averaged Navier-Stokes (RANS) equations to model the natural supercavitation process. The multiphase flow is considered as a mixture of varying density and modeled by the mass exchange equations. To fully understand this process, numerical simulations were performed for different annular cavitators. Computational Fluid Dynamics (CFD) results, including the pressure distribution and forces acting on the cavitator surface, mass flow and pressure loss of water injection, various supercavity sizes, were obtained and analyzed. The pressure distribution on the cavitator surface was significantly changed which resulted in 4 ~ 6% increase of the total drag of the vehicle. The results show that the mass flow and velocity of the injection water is mainly dependent on the tube size, while the total pressure loss of the water injection is mostly related to the outlet pressure. Supercavity generated by annular cavitator is smaller than that of the discal one. Based on the correlation analysis of the supercavity size and other factors, it could be concluded that the contraction of the cavity size is mainly caused by the diffluent mass flow of the water injection.

Open access

Hong Cao, Yuansong Zhang, Jianqing Zai, Honggang Lai, Yunsheng Jiang, Huan Xiao and Yan Han

Open access

Guang-Wei Zhang, Hu-Yuan Zhang, Jin-Fang Wang, Lang Zhou, Ping Liu and Xiao Jiang

Abstract

The objective of this paper is to evaluate the self- healing properties of a commercially-available geosynthetic clay liner (GCL) using flexible-wall permeameter. The GCLs are produced by the same factory, but the contents of bentonite are different. Also the hydraulic conductivities (HC) of GCLs with no defect are different. In this study, specimens were completely saturated under the backpressure of 20 kPa before the test. Permeability tests were performed on GCL specimens with penetrating flaw and also on specimens permeated with distilled water and CaCl2 solutions. The test results were presented and discussed. Experimental results showed that the GCL with penetrating flaw did not exhibit complete self-healing in the case of flaw. After 120 days, the hydraulic conductivity increased by approximately an order of magnitude. In addition, CaCl2 solutions had a significant influence on the hydraulic conductivity. The research findings might be of interest to researchers and engineers who design liners for landfills and other liquid containment facilities

Open access

Yu Cao, Jiang Zhang, Wei Yang, Cheng Xia, Hong-You Zhang, Yan-Hui Wang and Chuang Xu

Abstract

Introduction: The predictive value of selected parameters in the risk of ketosis and fatty liver in dairy cows was determined.

Material and Methods: In total, 21 control and 17 ketotic Holstein Friesian cows with a β-hydroxybutyrate (BHBA) concentration of 1.20 mmol/L as a cut-off point were selected. The risk prediction thresholds for ketosis were determined by receiver operating characteristic (ROC) curve analysis.

Results: In the ketosis group, paraoxonase-1 (PON-1) activity and concentration of PON-1 and glucose (GLU) were decreased, and aminotransferase (AST) activity as well as BHBA and non-esterified fatty acid (NEFA) contents were increased. The plasma activity and concentration of PON-1 were significantly positively correlated with the level of plasma GLU. The plasma activity and concentration of PON-1 were significantly negatively correlated with the levels of AST and BHBA. According to ROC curve analysis, warning indexes of ketosis were: plasma PON-1 concentration of 46.79 nmol/L, GLU concentration of 3.04 mmol/L, AST concentration of 100 U/L, and NEFA concentration of 0.82 mmol/L.

Conclusion: This study showed that the levels of PON-1, GLU, AST, and NEFA could be used as indicators to predict the risk of ketosis in dairy cows.