Wang J.-G.,Huazhong Agricultural University |
Yu B.,Huazhong Agricultural University |
Yang W.,Hubei Water Resources Research Institute |
Cheng J.-N.,Huazhong Agricultural University |
And 2 more authors.
Catena | Year: 2017
During slope erosion, the travel and abrasion of aggregate during transport may produce finer and more transportable particles, causing a significant effect on the sediment transport capacity and erosion intensity. Little information is available on the effect of roughness on aggregate abrasion in overland flow. This study investigated the potential effects of slope gradient, flow discharge, and roughness on aggregate abrasion and hydraulic characteristics in overland flow. These factors were studied with a series of aggregate abrasion experiments in a 3.8 m long flume at four slope gradients (8.7%, 17.6%, 26.8%, 36.4%), five discharges (0.4 L s− 1, 0.6 L s− 1, 0.8 L s− 1, 1.0 L s− 1, 1.2 L s− 1), and five surfaces of artificial rough beds. The results indicated that the different roughness conditions (with contributions of 63.5%) had obvious effects on the abrasion of aggregate compared to the slope gradient and discharge. Regardless of the discharge and slope gradient, the abrasion degree of aggregate gradually increased as the roughness increased. The changes in the abrasion degree of the aggregate were not the same at the different combinations of discharge and slope for each artificial rough bed. Flow depth can well explain the extent of abrasion of the aggregate for the single fixed rough bed. However, the abrasion degree of the aggregate had no significant variation with increases in the flow depth from all the data of the five artificial rough beds. The ratio between the residual weight and initial weight of soil aggregates (Wr/Wi) decreased in a power function with increase in the friction factor and shear stress from all the data of the five artificial rough beds. The friction factor and shear stress should be appropriate indicators to reflect aggregate abrasion under various roughness conditions in overland flow. The information of the analysis of the abrasion of soil aggregate under different artificial rough beds can be useful for the development of soil process-based erosion models. © 2017 Elsevier B.V.
Liu L.,Wuhan University |
Liu L.,Hubei Water Resources Research Institute |
Cui Y.,Wuhan University |
Luo Y.,Hohai University
Journal of Irrigation and Drainage Engineering | Year: 2013
The Yellow River Basin is a closed basin under serious stress with dense population, intensive agriculture, and excess water withdrawals. Low water use efficiency and groundwater overexploitation are threatening the sustainable development of the basin. This paper describes a coupled modeling approach to analyze sustainable management strategies in surface-groundwater conjunctive use irrigation districts in the lower Yellow River Basin. An appropriate irrigation schedule and an optimal range of groundwater levels are first established using the soil water atmosphere plant (SWAP) model with data from an irrigation experiment station. The integrated surface water and groundwater model was then set up using modified soil and water assessment tool (SWAT2000) and modular three-dimensional groundwater flow model (MODFLOW) models. The two models were connected through standardized simulation grids and calibrated using field measurements. Five scenarios that were designed according to different well-canal irrigation supply ratios and the irrigation schedule determined by SWAP were tested using the integrated modeling approach. It is proved that conjunctive management strategies of canal diversions and tube-well pumps can effectively reduce phreatic evaporation losses, increase water use efficiency, and sustain groundwater levels while maintaining crop yields at current levels. © 2013 American Society of Civil Engineers.
Yu M.,Hubei Water Resources Research Institute |
Zhang H.,Central China Normal University
Journal of Hohai University | Year: 2015
Based on review of research on suitable water levels for landscape functions and water demand for landscape environment, the concept and characteristics of the suitable water level for landscape functions of lakes are discussed. The suitable water level for landscape functions of lakes is affected by various factors, including flood control and drainage, municipal drainage, irrigation water supply, water resources of rivers and lakes, shipping, ecological water demand, and quantity of water diverted. In view of the landscape function of lakes and based on analysis of the main factors influencing the suitable water level for the landscape function of lakes during the flood season and dry season, quantitative calculation models of the suitable water level for the landscape function of lakes in the flood and dry seasons were established, through overall coordination of different functions of lakes. Then the suitable water levels for the landscape function of Wangmu Lake were calculated using the models. The results show that the modeled water level for the landscape function of Wangmu Lake in the flood season is 22.5 m, which is higher than the water level needed for comprehensive utilization of water resources (21.2 m). This modeled water level in the flood season not only improves the security of flood control and drainage, but also ensures the irrigation and shipping functions of the lake and existence of fish. The modeled water level for the landscape function in the dry season is 21.9 m, with the distance between the leisure activity platform and the water surface being less than 0.5 m, and the water quantity necessary for diversion into the lake being 9.362×106 m3. This water level not only helps optimize the water landscape, investment, and the water quantity diverted from other basins, but also ensures the feasibility of shipping and meets the requirement of minimum ecological water demand. ©, 2015, Editorial Office of Journal of Hohai University (Nature Sciences). All right reserved.
Yuan N.,Yangtze River Scientific Research Institute |
Huang J.,Yangtze River Scientific Research Institute |
Huang Z.,Hubei Water Resources Research Institute |
Xie H.,Wuhan University |
Wu M.,Wuhan University
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2012
In order to study the effect of combination of controlled drainage and nitrogen application on nitrogen migration and transformation in dryland, a compared test-pit experiment was conducted in Yajiao Drainage and Irrigation Station in Hubei province. Nine treatments, named H30, H50, H100, C30, C50, C100, L30, L50 and L100 were studied with two factors, controlled drainage water table with three levels 30, 50 and 100 cm, and nitrogen application with three levels, high, conventional and low level. Nitrate and ammonia contents in the soil layers were measured. Results showed that under the conventional nitrogen application level, nitrate content was highest in the treatment C100, and lowest in the treatment C50. Under the low nitrogen application level, ammonia content was highest in the treatment L30. When the water table was same, ammonia content was lowest in the treatment H30, H50 and H100. When the nitrogen application level was same, ammonia content sorted by controlled water table was 30 > 50 > 100 cm. Under the same nitrogen application level, controlled drainage can improve the stability of the nitrogen. Under the controlled drainage condition, there was no need to increase or decrease the nitrogen application while the nitrogen stability was high. Under the conventional drainage condition, reducing the nitrogen application can promote the nitrogen stability.
Liu L.,Wuhan University |
Liu L.,Hubei Water Resources Research Institute |
Cui Y.,Wuhan University |
Wu X.,Hubei Water Resources Research Institute
Shuikexue Jinzhan/Advances in Water Science | Year: 2013
In order to accurately evaluate the water use efficiency in irrigation districts, several new indices were proposed to measure the efficiency and benefit of water use in this study. The water balance components are simulated using integrated surface and groundwater models in the Liuyuankou Irrigation District (LID). Thus, the new indices take into account the influence of return flows. The Statewide Agricultural Production (SWAP) model and a liner model are used to simulate the crop yields in the LID. On this basis, the indices measuring water use efficiency and benefit can be calculated and analyzed for different patterns of water-use. The influence of various water saving measures on the efficiency and benefit of water use is discussed. Results show that although, over different regions of LID, the results of well-canal combined irrigation mode and water-saving irrigation mode can be different in terms of water use efficiency. The use of both modes can improve the overall efficiency and benefit of water use in the LID. The study provides a theoretical method and theoretical basis for the water use assessment in irrigation districts.
Fang N.-F.,Northwest University, China |
Fang N.-F.,CAS Institute of Soil and Water Conservation |
Shi Z.-H.,Northwest University, China |
Shi Z.-H.,CAS Institute of Soil and Water Conservation |
And 5 more authors.
Catena | Year: 2012
This paper analyzes runoff and soil loss in relation to the rainfall regimes and land use changes in a small mountainous watershed in the Three Gorges Area (TGA) of China. Based on 10. years of rainfall measurements and K-means clustering, 152 rainfall events were classified into three rainfall regimes. The mean statistical features of different rainfall regimes display a marked difference. Rainfall Regime I is events of medium amounts (31.8. mm) and medium duration (1371. min). Rainfall Regime II is events with high amounts (54.0. mm), long duration (2548. min), and an infrequent occurrence. Rainfall Regime III is events of low amount (22.2. mm), short duration (494. min) and high frequency. Each rainfall regime results in differing levels of runoff and erosion and Rainfall Regime I causes the greatest proportion of accumulated discharge (368.7. mm) and soil loss (4283. t). In the different rainfall regimes, the values of the mean runoff coefficient and the mean sediment load were ordered as follows: Rainfall Regime II > Rainfall Regime I > Rainfall Regime III. These results suggest that greater attention should be paid to Rainfall Regimes I and II because they had the most erosive effect. In the Wangjiaqiao watershed, the changes in land use primarily affected the paddy fields, where the cropland decreased significantly and the forest and orchards increased by 9.9% and 7.7%, respectively, during 1995-2004. The ANOVA shows land use changes caused significant decreasing trends in the runoff coefficients (P < 0.01) and sediment loads (P < 0.01). In order, the most sensitive response of runoff and erosion to land use was Rainfall Regime II > Rainfall Regime > Rainfall Regime III. Rainfall characteristics are decisive for the relative importance of different storm runoff generation mechanisms. The land use changes in the study watershed have considerably decreased runoff and soil loss. © 2012 Elsevier B.V.
Ma R.,Huazhong Agricultural University |
Cai C.,Huazhong Agricultural University |
Li Z.,Huazhong Agricultural University |
Wang J.,Huazhong Agricultural University |
And 3 more authors.
Soil and Tillage Research | Year: 2015
Soil structure and the soil pore system are important for many soil environmental processes. However, little is known about the influence of intra-aggregate microstructure on aggregate stability. The objective of this study was to evaluate the effect of soil pore characteristics on wet aggregate stability and aggregate tensile strength (TS) using synchrotron-based X-ray micro-computed tomography (SR-μCT) under wetting and drying cycles. Undisturbed topsoils (200cm3) derived from shale (S) and Quaternary red clay (Q) were submitted to three wetting and drying treatments under controlled laboratory conditions. 3-5mm aggregates were collected from different treatments and scanned at 3.7μm voxel-resolution for the reconstruction of 3D micro tomography images. The wet aggregate stability and TS were measured after each treatment. The relationships among pore characteristics, wet aggregate stability, and TS were analyzed using partial least squares regression (PLSR). The results indicated that porosity (P), percentage of pores >100μm (Pd100), and fraction of elongated pores (FEP) all significantly increased with an increasing number of wetting and drying cycles, while the opposite trends were observed for the total number of pores (TNP), the percentage of pores with a diameter of 75-100, 30-75, and <30μm. Decrease in wet aggregate stability and TS of both soils was mainly due to higher P, a more extensive and complex pore network, which caused increased air pressure, increased rate of water entry, and high probability of crack propagation and interaction. The TNP, Pd75-100, P, and Pd100, were identified as the primary factors controlling the wet aggregate stability and TS according to PLSR. The pore characteristics and soil clay content accounted for as much as 99% of the variation in wet aggregate stability and TS. This study provides insights for improved understanding of the change in topsoil microstructure; however, the effect of pore characteristics on the aggregate breakdown mechanism requires further investigation. © 2015 .
Shao H.,Jianghan University |
Wang Z.,Hubei Water Resources Research Institute |
Xu W.,Yangtze River Scientific Research Institute
Advances in Intelligent and Soft Computing | Year: 2012
Orthogonal projection lanczos algorithm is the effective way to solve the complex structural vibration, vibration frequency and vibration mode. Its idea is to translate high-level vibration problem into low-level to solve the vibration problem without losing eigenvalue. In this paper, a simple and convenient method of computing is presented using Orthogonal Projection lanczos algorithm to solve semi-definite matrix generalized eigenvalue problems and re-solve the eigenvalue. © 2012 Springer-Verlag GmbH.
Hu L.,Harbin Engineering University |
Jiang S.,Harbin Engineering University |
Zhang Y.,Harbin Engineering University |
Zhao Y.,Harbin Engineering University |
And 2 more authors.
Intermetallics | Year: 2016
A Ni-rich NiTi shape memory alloy (SMA), which was in its austenitic state at ambient temperature, was subjected to plastic deformation by means of local canning compression at various temperatures ranging from room temperature to 800 °C. Depending on temperatures, NiTi SMA exhibited multiple plastic deformation mechanisms, such as dislocation slip, deformation twinning, grain boundary slide, grain rotation, dislocation climb and grain boundary migration. Amorphization, dynamic recovery and dynamic recrystallization of NiTi SMA were also observed at various temperatures. Mechanism of localized amorphization, in particular, was investigated based on dislocation slip and deformation twinning. Statistically stored dislocation (SSD) and geometrically necessary dislocation (GND) were found to play an important role in the amorphization of the current NiTi SMA. There appeared a critical dislocation density below which NiTi SMA was unable to amorphize. Accordingly, at a fixed deformation strain, there should be a critical temperature above which amorphous phase would not occur in the NiTi SMA matrix. Furthermore, when NiTi SMA experienced plastic deformation at the critical temperature, amorphization and crystallization would occur simultaneously and compete with each other. © 2015 Elsevier Ltd. All rights reserved.
Wei J.,Beijing Forestry University |
Huang K.,Beijing Forestry University |
Yang S.,Hunan Academy of Social science |
Li Y.,Hubei Water Resources Research Institute |
And 2 more authors.
Journal of Cleaner Production | Year: 2016
Low carbon dioxide (CO2) emissions are the foundation on which to realize the sustainable development of a green China. Recently in Beijing, the capital of China, serious environmental pollution-climate anomaly, severe haze and human sub-health have been accorded more importance. This study examines the energy-related CO2 emissions generated by Beijing industries from 2000 to 2010 by using an input-output analysis method. The direct, indirect and total CO2 emissions of sectors in Beijing were calculated. In addition, structural decomposition analysis (SDA) was conducted to evaluate the driving factors from the perspective of technology, sectoral connection, economic structure and economic scale. The results show that the growth rate of sectoral CO2 emissions in Beijing has drastically increased during this time with a moderate decline during 2007-2010. The metal and non-metal mining industries, the electric power, gas and water supply sector and the construction industry caused the most CO2 emissions. The economic structure change and the rapid economic growth led to the significant increase in CO2 emissions growth in Beijing. Thus, optimizing the economic structure and improving the technology are important to alleviate CO2 emissions. Although we can currently appropriately utilize fossil fuels, further research on new energy and clean development, as well as enhanced government management strength is required to reduce CO2 emissions. © 2016 Elsevier Ltd.