bluuebunny/crossref_metadata_2025 huggingface dataset:
Facile fabrication of ZrO2@PMMA@polysiloxane nanohybrids and their application for light diffusing films
Authors: Bu Xiaohai , Li Dongxian , Zhang Zewu , Hong Chaofeng , Zhang Li , Yang Xiaoming
Published: December 2018

In this study, novel zirconium dioxide (ZrO2)@poly(methyl methacrylate (PMMA)@polysiloxane nanohybrids were facilely synthesised using a one‐pot suspension polymerisation route. Various characterisations including Fourier transform‐infrared, X‐ray diffraction, thermogravimetric analysis, scanning electron microscopy, and transmission electron microscopy were performed to record the components and morphology of the ZrO2@PMMA@polysiloxane nanohybrids. The nanohybrids were used as fillers in optical acrylate resins to enhance the optical properties of bare PET film. The ultraviolet (UV)–visible spectra show that the nanohybrids can absorb harmful UV rays, which has a great effect on prolonging the service life of light‐diffusing films. The results also show that the transmittances of the films slightly decrease with the increasing filler loading, while the haze values increase. High transmittance and enhanced haze of the films could be achieved by incorporating 6% nanohybrids, which was better than commercial goods.
Hubble flow variations as a test for inhomogeneous cosmology
Authors: Saulder Christoph , Mieske Steffen , van Kampen Eelco , Zeilinger Werner W.
Published: December 2018

Context.Backreactions from large-scale inhomogeneities may provide an elegant explanation for the observed accelerated expansion of the universe without the need to introduce dark energy.

Aims.We propose a cosmological test for a specific model of inhomogeneous cosmology, called timescape cosmology. Using large-scale galaxy surveys such as SDSS and 2MRS, we test the variation of expansion expected in the Λ-cold dark matter (Λ-CDM) model versus a more generic differential expansion using our own calibrations of bounds suggested by timescape cosmology.

Methods.Our test measures the systematic variations of the Hubble flow towards distant galaxies groups as a function of the matter distribution in the lines of sight to those galaxy groups. We compare the observed systematic variation of the Hubble flow to mock catalogues from the Millennium Simulation in the case of the Λ-CDM model, and a deformed version of the same simulation that exhibits more pronounced differential expansion.

Results.We perform a series of statistical tests, ranging from linear regressions to Kolmogorov-Smirnov tests, on the obtained data. They consistently yield results preferring Λ-CDM cosmology over our approximated model of timescape cosmology.

Conclusions.Our analysis of observational data shows no evidence that the variation of expansion differs from that of the standard Λ-CDM model.
The AMBRE Project: [Y/Mg] stellar dating calibration with Gaia
Authors: Titarenko A. , Recio-Blanco A. , de Laverny P. , Hayden M. , Guiglion G.
Published: December 2018

Chemical abundance dating methods open new paths for temporal evolution studies of the Milky Way stellar populations. In this paper, we use a high spectral resolution database of turn-off stars in the solar neighbourhood to study the age dependence of the [Y/Mg] chemical abundance ratio. Our analysis reveals a clear correlation between [Y/Mg] and age for thin disc stars of different metallicities, in synergy with previous studies of solar-type stars. In addition, no metallicity dependence with stellar age is detected, allowing us to use the [Y/Mg] ratio as a reliable age proxy. Finally, the [Y/Mg]–age relation presents a discontinuity between thin and thick disc stars around 9–10 Gyr. For thick disc stars, the correlation has a different zero point and probably a steeper trend with age, reflecting the different chemical evolution histories of the two disc components.
Unveiling the enigma of ATLAS17aeu
Authors: Melandri A. , Rossi A. , Benetti S. , D’Elia V. , Piranomonte S. , Palazzi E. , Levan A. J. , Branchesi M. , Castro-Tirado A. J. , D’Avanzo P. , Hu Y.-D. , Raimondo G. , Tanvir N. R. , Tomasella L. , Amati L. , Campana S. , Carini R. , Covino S. , Cusano F. , Dadina M. , Della Valle M. , Fan X. , Garnavich P. , Grado A. , Greco G. , Hjorth J. , Lyman J. D. , Masetti N. , O’Brien P. , Pian E. , Perego A. , Salvaterra R. , Stella L. , Stratta G. , Yang S. , di Paola A. , Caballero-García M. D. , Fruchter A. S. , Giunta A. , Longo F. , Pinamonti M. , Sokolov V. V. , Testa V. , Valeev A. F. , Brocato E.
Published: December 2018

Aims. The unusual transient ATLAS17aeu was serendipitously detected within the sky localisation of the gravitational wave trigger GW 170104. The importance of a possible association with gravitational waves coming from a binary black hole merger led to an extensive follow-up campaign, with the aim of assessing a possible connection with GW 170104.

Methods. With several telescopes, we carried out both photometric and spectroscopic observations of ATLAS17aeu, for several epochs, between ∼3 and ∼230 days after the first detection.

Results. We studied in detail the temporal and spectroscopic properties of ATLAS17aeu and its host galaxy. Although at low significance and not conclusive, we found similarities to the spectral features of a broad-line supernova superposed onto an otherwise typical long-GRB afterglow. Based on analysis of the optical light curve, spectrum, and host galaxy spectral energy distribution, we conclude that the redshift of the source is probably z ≃ 0.5 ± 0.2.

Conclusions. While the redshift range we have determined is marginally compatible with that of the gravitational wave event, the presence of a supernova component and the consistency of this transient with the Ep–Eiso correlation support the conclusion that ATLAS17aeu was associated with the long gamma-ray burst GRB 170105A. This rules out the association of the GRB 170105A/ATLAS17aeu transient with the gravitational wave event GW 170104, which was due to a binary black hole merger.
Rotational spectroscopy of the HCCO and DCCO radicals in the millimeter and submillimeter range
Authors: Chantzos J. , Spezzano S. , Endres C. , Bizzocchi L. , Lattanzi V. , Laas J. , Vasyunin A. , Caselli P.
Published: December 2018

Context. The ketenyl radical HCCO has recently been detected in the interstellar medium (ISM) for the first time. Further astronomical detections of HCCO will help us understand its gas-grain chemistry, and subsequently revise the oxygen-bearing chemistry towards dark clouds. Moreover, its deuterated counterpart DCCO has never been observed in the ISM. A broad spectroscopic investigation is still lacking for both HCCO and DCCO, although they exhibit a significant astrophysical relevance.

Aims. In this work we aim to measure the pure rotational spectra of the ground state of HCCO and DCCO in the millimeter and submillimeter region, considerably extending the frequency range covered by previous studies.

Methods. The spectral acquisition was performed using a frequency-modulation absorption spectrometer between 170 and 650 GHz. The radicals were produced in a low-density plasma generated from a select mixture of gaseous precursors. We were able to detect and assign more than 100 rotational lines for each isotopolog.

Results. The new lines have significantly enhanced the previous data set allowing the determination of highly precise rotational and centrifugal distortion parameters. In our analysis we took into account the interaction between the ground electronic state and a low-lying excited state (Renner–Teller pair) which enables the prediction and assignment of rotational transitions withKaup to 4.

Conclusions. The present set of spectroscopic parameters provides highly accurate, millimeter, and submillimeter rest-frequencies of HCCO and DCCO for future astronomical observations. We also show that towards the pre-stellar core L1544, ketenyl peaks in the region wherec-C3H2peaks, suggesting that HCCO follows a predominant hydrocarbon chemistry, as already proposed by recent gas-grain chemical models.
Impact assessment on water resources management under extreme climate change
Authors: Liu Zhiming , Wang Yongqiang , Chen Jin , Xu Jijun , He Shaokun
Published: December 2018

River flows would be influenced greatly by climate change, which may cause further stress on water resources management by altering the quantity and distribution of runoff. In this paper, taking the Hanjiang River basin for instance, projections of precipitation and temperature are generated from two GCMs under RCP8.5 scenario, an extreme condition. Then the outputs are statistically downscaled and corrected by the daily bias correction method, a hybrid method of combining the daily translation and the local intensity scaling method. The VIC distributed hydrological model is used for the runoff simulation. Results show that the projections of two GCMs consistent with each other. There is a general increase in the annual mean precipitation and temperature in the Hanjiang River Basin in the future period (2021-2099), and the annual mean runoff of the Danjiangkou reservoir increases significantly compared with historical period (1980-2010). However, the annual runoff variability would increase the flood control pressure in wet season, aggravate the conflict between power generation and water supply in dry season despite increasing the water supply capacity in storage season.
Variation on sandbar of tributary in Xiaolangdi Reservoir on Yellow River, China
Authors: Li Tao , Zhang Jun-hua , Gao Guoming , Ma Huaibao
Published: December 2018

Sandbar development would stop the water and sediment exchange between main river and tributary and even influence the normal reservoir opeartion. From the surveyed data of reservoir built many years ago, it shows that when there is a bar in tributary mouth, the tributary volume below the bar will become nullification during the period of flood control or water and sediment regulation of reservoir. There are more tributaries in Xiaolangdi reservoir than the others that it occupies 41.3% of the total initial volume of tributary volume. Obviously, the effective use of tributary volume has been important influenced by comprehensive utilization efficiency of reservoir scheduling, such as flood control, sedimentation reduction and comprehensive utilization. Results of Xiaolangdi Reservoir mobile-bed physical model experiments show that tributary is equivalent to lateral extension of river bed, the tributary intrusion deposition process have strongly relations with the factors, such as original topography, river bed deposition shape and its regime, process with input discharge and input sediment, and method of reservoir regulation. The variation trends of main river and tributary terrain forecasted by model test are basically in accordance with field surveyed data. The results could be used for research, design, and forecasting of reservoirs in sediment-laden river.
Water demand forecast model of Least Squares Support Vector Machine based on Particle Swarm Optimization
Authors: Yan Kun , Yang Min-Zhi
Published: December 2018

In order to solve the problem of precision of water demand forecast model, a coupled water demand forecast model of particle swarm optimization (PSO) algorithm and least squares support vector machine (LS-SVM) are proposed in this paper. A PSO-LSSVM model based on parameter optimization was constructed in a coastal area of Binhai, Jiangsu Province, and the total water demand in 2009 and 2010 were simulated and forecasted with the absolute value of the relative errors less than 2.1%. The results showed that the model had good simulation effect and strong generalization performance, and can be widely used to solve the problem of small- sample, nonlinear and high dimensional water demand forecast.
Analysis of the Ecological Effects of Decadal Large Scale Intermittent Annual Water Allocation using Satellite Data in Baiyangdian Wetland, Northern China
Authors: Wang Fei , Zhao Ying
Published: December 2018

In this study, the ecological effects of intermittent water allocation with emphasis on spatiotemporal responses of the corresponding vegetation were analyzed using remote sensing data and GIS-based buffer technology considering the period from 1st July 2000 to 31st December 2009. Three sampling sites (Angzh, Wangk, and Xidayang) with different water flow paths and three buffer distances were distinguished in the research. The Seasonal-Trend decomposition procedure based on Regression (STR) trend extraction and its corresponding linear regression and anomaly detection were executed to determine temporal variations of vegetation under the effects of water allocation. ANOVA and PCA methods were employed to identify the spatial responses of vegetation to different water flow paths and buffer distances. The results were as follows: (1) NDVI except NDVImin displayed higher values during the period without water allocation; (2) extremely significant decline trends (p<0.001) of all NDVI categories were observed in all sites at all buffer distance levels, except for NDVImin at buffer distances of 2 km and 4 km in Angzh, showing stronger fluctuations of frequency after 2008 as well as the decline gradient with the extent of buffer distance to river. The anomaly detection results provided similar evidence of stronger NDVI fluctuations after 2008; (3) water allocation had extremely significant effects on regional vegetation coverage (p<0.01) with a decline gradient of statistical p values along enlarged buffer distances. Our results provide evidence of spatial and temporal differences in vegetation response to water availability due to the intermittent frequency water allocation implemented via different river channels. The findings of this study will deepen our understanding of the effects of water division on regional vegetation restoration and can be used to develop a practical strategy for effective implementation of water allocation.
Brief discussion on the water-sediment regulation in the Ningxia-Inner Mongolia reach of the Yellow River under the changing environment
Authors: Li Xiaonan , Zhang Chen , Zhang Hongwu , Zhang Lisheng , Zhong Deyu
Published: December 2018

The effective reservoir sediment regulation measure is extremely significant for the sedimentladen river. It should not only extend the reservoir life, but also pose favorable conditions for the management of the river-reservoir system. Especially, the remarkable changes in the hydrological processes challenge to the system in some respects, like flood control, rive training, ecological environment improvement and so on. This paper gives a brief discussion on the representative existing problems in Ningxia-Inner Mongolia reach of the Yellow River. The water-sediment parameters and artificial regulation factors are then summed through a comprehensive literature review. Then we investigate the response to the different scales of floods in the Inner Mongolia reach through a three-dimensional model, in which the simulation region is from Bayangaole gauging station to Toudaoguai gauging station. With respect to the riverbed deformation, it is effective to control the relationship between the incoming water and sediment to restrain the shrinkage of the main channel; and surely that there exists a nonlinear relationship between channel scouring and incoming water-sediment conditions. Through data analysis and simulation results, the response characteristics of different watersediment regulation boundary conditions can be obtained, such as the ratio between sediment concentration and discharge, the discharge duration and the discharge, which is favorable to further water-sediment regulation of the reservoir and the management in Ningxia-Inner Mongolia reach of the Yellow River.
The Response Property of Inverted Siphon in Long Distance Water Distribution System
Authors: Mao Zhonghao , Guan Guanghua , Yang Zhonghua , Zhong Ke
Published: December 2018

In order to design controllers for canals with inverted siphon especially for very long siphon, it is necessary to learn its response property. Compared to open canals, the water movement in inverted siphon is very different due to the fast travelling speed of wave and high water pressure. It is impossible to use openchannel model describe invert siphon section, and the delay caused by the siphon haven’t been discussed in existing literature. This paper proposes a response model of inverted siphon which contains a delay and an integrator in low frequencies, a constant gain in high frequencies. By comparing the response model to the results of simulation, this paper shows the response model is a good approximation. This paper studies a water distribution project consists of two canals and one inverted siphon. The result shows that the water level change at downstream end is significantly smaller than water change at upstream end. By applying response model of inverted siphon, this paper shows it is due to the delay of flow rate change from upstream end to downstream end.
Analysis on influencing factors and simulation of sediment release by density current: the case of Xiaolangdi Reservoir
Authors: Wang Ting , Wang Yuanjian , Ma Huaibao , Qu Shaojun
Published: December 2018

Density current venting by bottom outlets is the main form of sediment release from large reservoirs during sediment retention periods. Taking Xiaolangdi Reservoir as a case study, this study analyzed influencing factors of sediment release by density currents and proposed a semi-empirical formula to simulate the density current release process. The results show that the amount of incoming water and sediment, length of backwater, and sedimentation volume upstream of backwater zones are the main factors influencing sediment discharge. However, the importance of influencing factors varies slightly for different sediment supply areas. The semi-empirical formula provides a good simulation of the actual sediment release process under a relatively stable water level, and thus, it can extend scientific and technical support necessary for reservoir operation.
Soil Water Balance and Water Use Efficiency of Rain-fed Maize under a Cool Temperate Climate as Modeled by the AquaCrop
Authors: Wang Weimin , Dong Xue , Lu Yanyun , Liu Xunliang , Zhang Ruining , Li Meng , Tian Linjing , Ding Yue , Pu Xiao
Published: December 2018

The AquaCrop model has been widely studied and examined for its feasibility and applic ability in simulating the crop growth – water relationship under tropical and warm temperate. How ever, the model is rarely tested under cool temperate climates. As the second largest agricultural ar ea of China, the Sanjiang Plain is characterized with relatively lower accumulative temperature and higher annual precipitation, showing typical features of a sub-humid and cool temperate climate. Th is study employed the AquaCrop model to compute soil water balance and water use efficiency of rain-fed maize in the Sanjiang Plain using a 5-year monitoring dataset (2011 – 2015). The results demonstrated an acceptable performance of AquaCrop in depicting soil water content, biomass accu mulation and grain yield. Soil water balance including soil water content, evapotranspiration and pr ecipitation was described throughout the growing period. The hysteresis of the daily soil water cont ent as responses to daily precipitation was revealed. Water use efficiency for the observed rain-fed maize increased with rising accumulative temperature and decreased with rising atmospheric CO2 c oncentration. This study provided a perspective for the extensive application of the AquaCrop mode l and the precise simulation in water dynamics under sub-humid and cool temperate climates.
A daily power generation optimized operation method of hydropower stations with the navigation demands considered
Authors: Jia Tianlong , Zhou Jianzhong , Liu Xiaoshen
Published: December 2018

Under the influence of hydraulic uncertainty, the various operational safety risks exist in the shortterm hydropower generation scheduling and navigation inevitably. Therefore, it is very crucial to establish a daily power generation optimized method of hydropower stations with the navigation demands considered. The daily power generation optimized operation method was established for generation scheduling and navigation problems of Xiangjiaba hydropower station during the dry seasons. Taking the mutual feedback relationship between the Hydraulic coupling of power generation and navigation as the pointcuts, an improved genetic algorithm was put forward with maximizing daily power generation. A two-dimensional flow model was carried out to validate constraints since the complex flow field was located at the entrance area of the approach channel. With the help of the software MIKE21 FM, the flow field data, such as the water surface lines, flow velocity and direction, was obtained by the numerical simulation. The results showed that the daily power generation optimization and numerical simulation methods could achieve the maximized daily capacity of hydropower station under the premise that ensuring the safety of navigation.
Comprehensive Benefit Allocation for Joint Operation of Multiple Reservoirs in the Ningbo Based on Shapely-Value Method and Benefit-Incremental Method
Authors: Song Peibing , Wang Chao , Yang Guanshe , Jing Xiao , Ding Gongbo
Published: December 2018

With the completion of interconnection project of the Eastern Reservoir Group, it is possible to realize the joint operation of the multiple reservoirs in the Ningbo, and integrated dispatching involving water supply and power generation has significant benefits. Based on the inequality of multi-stakeholders and the irrationality of benefit allocation in the cascade reservoir, this paper takes the joint operation of three reservoirs in Ningbo as an example and establishes a Shapley-value and benefit-incremental model, aiming at quantifying and sharing the compensation benefits. Results show that this method not only has strong operability, but also it has clear objectives that can be quantified. Moreover, this method takes the actual contribution value of different stakeholders into consideration. Thus, adopting this method is able to give full play to the enthusiasm of different reservoirs and achieve the maximum comprehensive benefit of the reservoir group.
Thirty Years of the Yellow River Water Allocation Scheme and future Prospect
Authors: wang Yu , Peng Shaoming , Jiang Guiqin , Fang Hongbin
Published: December 2018

Yellow River is an important source of water for northwest and north China, and an important strategic guarantee for the sustainable economic and social development of the Yellow River basin and its related regions. The Yellow River water allocation scheme (Scheme 1987 in short) was approved in 1987 by the State Council, which was the first river water allocation scheme in China. It allocates a total volume of 58 billion m3 of water to the 11 provinces along the river and its ecosystem. However, with the deepening impact of climate change and human activities, the Yellow River water resource and its development situations have some changes and the water resource of the drainage basin faces new situations, so it is urgent to carry out the optimization and adjustment study of Scheme 1987 under the new situation. The background and promulgation process of Scheme 1987 was reviewed comprehensively, and its implementation effect for 30 years was analyzed from two periods before and after unified dispatching. The new situation of the development of the Yellow River basin in the future was analyzed, and the work to be carried out to optimize and adjust the Scheme 1987 was prospected.
The practice and effectiveness of ecological operation experiment on spawning of the four major Chinese carps by Three Gorges Reservoir
Authors: Xu Wei , Chen Xiaojuan , Tao Jiangping , Jun Cao
Published: December 2018

Eco-operation experiment by the Three Gorges Reservoir was carried out ten times to facilitate spawning of the four major Chinese carps in the lower reaches of Yangtze River, from 2011 to 2017. To get knowledge of fish spawning response to man-made flood process, and also assessing the positive effect of eco-operation on fish spawning, fish eggs were monitored daily by drift-net method, in a fixed profile in Shashi reach between mid-May to mid-July each year. Basing on the consecutive data and research for seven years, the practice and effectiveness of TGR eco-operation experiment on fish spawning were summarized and prospected. The main findings were as follows: eco-operation experiment usually operated in a suitable condition from late May to the end of June. Based on the hydrological monitoring data in Yichang station, the continuous days of rising limb varied from 3 days to 9 days, the mean diurnal increment of water level varied from 0.43 m to 1.30 m, and the water temperature varied from 20℃ to 24℃, except in 2013 that only below 18℃, during eco-operation period within seven years. According to the fish eggs monitoring data in Shashi reach, annual egg abundance of the four major Chinese carps ranged from 116 to 610 million, grass carps and silver carps were two dominant species with proportion of more than 80%. Egg abundance of the four carps produced in eco-operation period accounted for about 38% averagely of total amount in the whole monitoring period, with nine floods in total of thirty-three floods. Four indicators representing fish spawning performance, the time interval from water rising to spawn happening, duration time of spawning, extent of spawning grounds, and spawning scale, were calculated in each spawning event corresponding to each flood process. All indicators gave evidence that spawning performance of the four carps were better in eco-operation period, compared with other routine operation period. It was concluded the Three Gorges Reservoir eco-operation had done its work on boosting spawning of the four major Chinese carps, but further and foremost research should be developed on the following aspects, quantifying the eco-operation effect, optimizing the eco-operation index, and extending the eco-operation target to other important life history stage of fishes.
Spatial variability and temporal trends of precipitation over the Loess Plateau of China: 1957-2013
Authors: Yang Yu , Yin Zhe , Shan Zhijie , Wei Qin , Li Bai , Guo Qiankun , Wei Long , Wang Qun , Zhang Jingfeng
Published: December 2018

Accurate information about regional precipitation and trends in spatiotemporal variation is crucial, both from the perspective of quantifying water budgets and to determine appropriate vegetation restoration. The objectives of this study were to evaluate spatiotemporal changes in precipitation and to analyze the monthly, annual, and seasonal precipitation trends of 85 stations in the Loess Plateau during 1957−2013. The Mann−Kendall test and Sen’s slope estimator were applied to analyze the precipitation data. Monthly precipitation trends exhibited apparent regional differences over the Loess Plateau, significant increasing trends in rainfall were found in winter. On the seasonal scale, the magnitude of significant negative trends in seasonal rainfall varied from 0.595 mm/yr2 to 2.732 mm/yr2. The magnitude of significant positive trends varied from 0.010 mm/yr2 to 1.987 mm/yr2. One of the most remarkable findings was that all the stations showed significant positive trends in winter. For annual average rainfall, the magnitude of significant positive trends varied from 2.075 mm/yr2 to 3.427 mm/yr2. No significant negative trends were detected. Although, the annual average rainfall over the Loess Plateau showed a non-significant increasing trend, the seasonal and regional pattern was obvious. Such findings can provide important implications for ecological restoration and farming operations across the study region.
Comparative analysis of seepage simulation for embankment in cold area during ice flood season and non-ice flood season
Authors: Chen Mo , Dai Changlei , Li Yang
Published: December 2018

Influenced by meteorological and environmental factors, ice flood is easy to occur in cold areas, causing the flood level to rise substantially and threatening the safety of embankments. Based on the analysis of the influencing factors of the seepage of the dike in the cold region, the seepage simulation model of the dike is constructed and solved by the SEEP/W module of Geo-studio software. The seepage of the Dike Section in the ice flood season and non-ice flood season under the scenario of 100-year flood level is compared and analyzed. The results show that, (1) The seepage path of non-ice flood dike mainly passes through the base layer of the dike, and the seepage path of the dike is affected by the frozen shell during the ice flood season, and the seepage path of the dike mainly passes through the frozen shell. (2) The maximum velocity of Dike Seepage in the season of ice flood is higher than that in non-ice flood season, which is easy to cause piping and collapse. (3) the maximum gradient of the embankment during the flood season has also increased, exceeding the allowable slope value of the project. During the season of ice flood, the embankment is unstable, and the embankment protection should be strengthened during the flood season.
The applicability of A Modified Palmer Drought Severity Index on Agricultural Drought Evaluation in the North China
Authors: Yang Mingzhi , Xiao Weihua , Zhao Yong , Li Baoqi , Wang Yan , Yang Heng , Hou Baodeng
Published: December 2018

Agricultural irrigation is an important factor affecting the development of agricultural drought, which is not showed in the Palmer Drought Severity Index (PDSI). In this work, the water balance model in PDSI has been modified by adding irrigation items, which improves the accuracy of the calculation results of the model and shortens the calculation time step. The modified Palmer Drought Severity Index (M_PDSI) is constructed by using daily weather data and irrigation data from 1985-2012 in the study area. Weekly indices cumulated in each growth stage are used for the implementation of crop models by a linear multiple regression model. The crop yield models are evaluated to determine a more appropriate agricultural drought index between M_PDSI and PDSI by comparing the predicted yields to the observed yields. By comparing the development of agricultural drought, it can be seen that the M_PDSI can improve the sensitivity to the dynamic change of soil wet and dry in short-term, and the development process of drought is more in line with the actual situation; by comparing the fitting test results of the predicted yields, it can be seen that, the M_PDSI ranks better than the PDSI in all four goodness-of-fit measures, M_PDSI is proved to be more suitable than PDSI for evaluating agricultural drought.
Brief Analysis of Urban Levee Management with Modern Information Technology – A Case Study in Yangzhong
Authors: Zhao Xueying , Zhao Xiaoqiu , Zhang Shunfu
Published: December 2018

due to geological location and special landform, Yangzhong City often suffers from flooding of Yangtze River, typhoons and rainstorms, hence facing severe challenges in flood prevention. Meanwhile, with its rapid economic development and urban expansion, the population density increases within the levee, which imposes higher standards for levee safety. With modern information technology and introduction of the concept of whole-life cycle, a levee safety monitoring and early-warning system can be built to monitor the operation, provide technical support for safety management and operation.
Multi-time scale analysis of hydrogen and oxygen isotope characteristics and influence factors in precipitation in Vienna
Authors: Hu Yue , Liu Guo-dong , Xia Cheng-cheng
Published: December 2018

Based on isotope and meteorology data at Vienna station from 1972 to 2014 provided by GNIP, the average monthly and annual hydrogen and oxygen stable isotopic compositions and main factors were analyzed by using various trend analysis, periodic analysis and correlation analysis methods. The monthly mean isotopic compositions change slightly, reflecting the fact that although Vienna is affected by the maritime climate and the continental climate, the former impact is more significant. The slope and intercept of the LMWL in Vienna changed significantly from October to March, indicating that it was affected by alternating effects of the two climates. The annual mean isotopes show a trend of enrichment, and it has an obvious temperature effect, but the rainfall amount effect does not exist, and no simple linear relationship was found between isotopes and vapor pressure. The annual mean isotopes also show the periodic variation characteristics with scales such as 9-16 years and 18~29 years, and it is concluded that the isotope values will be enriched after 2011 at the scale 22 years. The multivariate regression relationship established by δD and δ18O with three climate parameters of temperature, precipitation and vapor pressure can quantitatively estimate the missing value in isotopic data.
The status quo and development trend of smart water research
Authors: Zhu Zhaohui , Liu Ning , Li Xiuwen , Yuan Zhaowei , Wang Guochuan
Published: December 2018

Smart Water uses sensor equipment to sense natural water and social water circulation system, to achieve real-time monitoring and dynamic collection, scheduling and remote management of water information through Internet of Things, and to realize the deep processing of multi-source heterogeneous data through the data mining and multi-dimensional analysis of the information system, which provides an important reference for the intelligent management and decision-making of urban water affairs. With the continuous innovation of information technology such as big data and cloud computing, smart water development has ushered in new opportunities. This paper mainly summarizes the status quo of smart water research at home and abroad from the perspective of application practice, and analyzes the main problems facing the development of smart water in China. the development trend of smart water is proposed according to the current technological development and industry needs.
Study on Optimal Operation of Hydropower Station Group Based on New Electricity Reform and Deviation Assessment
Authors: Zhu Yanmei , Chen Shijun , Huang Weibin , Xie Diya , Li Wang , Ma Guangwen
Published: December 2018

The new electricity system reform has brought power generation companies into the market, and the scheduling target of cascade hydropower stations has been transformed from maximizing power generation to maximizing revenue. Market rules require hydropower generators to pay assessment fees for the power generation deviation. Therefore, in order to obtain the desired revenue, power generators should not only obtain more power generation indicators and higher power prices, but also control the power generation deviation and avoid being assessed. In response to the current market environment, the new requirements of the new electricity system reform for hydropower scheduling were analyzed. And based on regional market rules, a scheduling model for cascade hydropower stations with the goal of minimizing generation deviation was established, taking the example of eight cascade hydropower stations in the downstream of Dadu River in Sichuan province as an example, the effectiveness and applicability of the model were verified. The results show that the deviation in each period can be controlled within 1% and meet the basic requirements of market rules.
Research on Intelligent Location Method of Water Supply Pipe Network Burst Based on BP Neural Network Deep Learning
Authors: Wang Luohua , Lv Mou , Miao Xiaobo , Li Li , Liang Fengchao
Published: December 2018

Based on the in-depth analysis of the causes of the large-scale water supply pipe network explosion at home and abroad, the paper discusses the neural network modeling technology for quickly and accurately locating the water pipe network. Furthermore, the remedial measures of the pipe network squib in the field were adopted, and the BP neural network deep learning method was proposed to carry out the intelligent positioning of the water pipe network bursting. Based on the construction of a miniature hydraulic model based on BP neural network analysis, through the correlation analysis of the flow change of 5 positions and the pressure monitoring point change of 17 positions when the pipe network bursts, the artificial neural network deep learning is further used to diagnose the position of the pipe network where the pipe burst is located. In this paper, the small-scale water supply pipe network built by the laboratory is taken as an example to verify the research method of the pipe burst positioning.
Metabolic grey early warning model for dam deformation based on wavelet denoising
Authors: Wu Yunxing , Gu Yanchang
Published: December 2018

Influenced by environment and human factors, the observed data of dam deformation consist of real deformation value and observation error (noise). The conventional GM(1,1) model based on nondenoised observation data is not very effective. In order to improve the prediction effect of conventional GM(1,1) model, wavelet threshold denoising method is used to eliminate the noise in the original data and improve the smoothness of the data sequence. Then, based on the conventional GM(1,1) model, the metabolic GM(1,1) model is established by eliminating the oldest information and adding the newest information. The application results show that the wavelet threshold denoising can obviously remove the noise from the original data. The predicted vertical displacement of the metabolic GM(1,1) model based on the denoised data has little difference with the measured value, and the predicted precision is obviously higher than that of the conventional GM (1,1) model. Therefore, the metabolic GM(1,1) model based on wavelet denoising can be used for prediction and early warning of dam deformation.
Study on the Construction Mode of Water Ecological Civilization in Coastal Cities——Taking Shenzhen as an Example
Authors: Fu Hanxiu , Liu Yong , Chen Yuanfang , Hu Jian , Zhang Ying , Hu Qingfang
Published: December 2018

Based on the present situation of water ecological civilization construction in Shenzhen, the paper summarizes the path of water ecological civilization construction with Shenzhen characteristics. That is to say, the construction is around the development vision of “river and sea are calm and peaceful, green mountains and clear water, modern livable, beautiful Pengcheng”, to create the eight major systems of water safety, water environment, water ecology, water conservation, water management, water landscape, water economy and water culture according to local conditions on the basis of the spatial layout of “nine basins and four sections, three bays and two belts, five-point and dual-core”. This construction mode provides an important reference for promoting the governance of Shenzhen water problems under the guidance of the concept of ecological civilization and provides a model reference for the construction of water ecological civilization in coastal cities[1,2,6].
Utilization of a Bayesian probabilistic inferential framework for contamination source identification in river environment
Authors: Jing Lijun , Chen Ruihui , Bai Xiaomei , Meng Fansheng , Yao Zhipeng , Teng Yanguo , Chen Haiyang
Published: December 2018

In the environmental event of hazardous release into river, quick and accurate identification of the contamination source is important for emergence response. Generally, given a noisy and finite set of monitoring information, determining the source items (i.e. location, strength and release time) is an ill-posed inverse problem. In this study, a Markov chain Monte Carlo method combined with advection-dispersion equation (ADE) was proposed for the source identification of contamination event in river system based on a Bayesian probabilistic inferential framework. Case study with analytical solution for one-dimensional ADE showed that the proposed methodology was effective and the mean posterior errors for all source parameters were lower than 3%. Case simulation based on two-dimensional ADE with numerical solution obtained similar results and further demonstrated the utility of the proposed approach for source identification. We hope the study will provide a helpful guidance to develop approach for contamination event source identification to support environmental risk management of river system.
Analysis of Water Cycle in Weizhou Island of Beihai City, Guangxi Province, Part II: Study On Groundwater Exploitation Plan
Authors: Zhang Shunfu , Liu Changjun , Li Chuanke , Long Sili , Zhou Jian , Zhang Qiyi
Published: December 2018

To relieve the drop of groundwater and seawater intrusion in Weizhou Island caused by overexploitation, the analysis model of precipitation-runoff and variable-density groundwater flow in Weizhou Island was established and the model’s parameter identification results were used to investigate groundwater level and seawater/freshwater interface changes under different groundwater exploitation plans. Thereafter, a rational groundwater exploitation plan could be made to prevent the lowering of groundwater levels caused by ground water overexploitation and ecological deterioration caused by seawater intrusion. This could help accelerating the recovery of ground water and maintaining ecological system.
Optimizing the planting structure in Daxing District in 2020 based on inaccurate two-stage planning model and grey model
Authors: Wang Zhipeng , Dai Wei , Shi Yuan , Bai Meijian , Liu Qunchang , Zeng Xin
Published: December 2018

In order to optimize the planting structure and use water more efficiently, an inaccurate two-stage planning model is proposed in this paper. This model can not only reflect uncertainty of the probability distribution in the form of the possible distribution interval, but also build a recourse relationship between expected benefits and penalties for failing to achieve target goals. The two-stage planning model, combined with the gray GM (1.1) model, is applied to Daxing district of Beijing to optimize and adjust planting areas of the grain crops, fruits and vegetables, and garden plots in 2020. In the meantime, three scenarios were established for comparative analysis. Results show that after optimization, the economic benefits of above-mentioned three planting areas in Daxing district in 2020 is 3.71 billion CNY, an increase of 348 million from 2016 CNY; the total water consumption is 64.17 million cubic meters, a decrease of 62.79 million cubic meters from 2016. Results indicate that this model method is feasible for optimizing planting structure, and to some extent, can provide decision-making support and a theoretical basis for planting structure optimization and prediction in similar areas to Daxing district.
Multi-layered Nonnegative Matrix Factorization Based on PCA for the Foreign Object Detection in Electricity Meters
Authors: Jin Zhang , Yang Ou Xi , Jian Wu , Xi Ou , You Zhou , Chang Ji
Published: December 2018

Foreign object detection is an important part of quality control of electricity meters. An automatic detection device is developed based on acoustic identification. In order to suppress background noise interference, we design a novel sound separation algorithm to separate the mixed sound signals to obtain the target source signal produced by foreign objects. Firstly, the improved principal-component-analysis-based multi-layered nonnegative matrix factorization (PMNMF) is used to separate sound signals. Secondly, the SVM is used to classify and identify sound signals. A suppot vector machine (SVM) as the classifier is used to compare the PMNMF algorithm with the basic NMF algorithm. The results indicate that the sound data pre-processed with the improved NMF algorithm results in a significantly higher identification rate up to about 95%.
Experimental Study to Develop Writing skills through Blended Learning in the Times of Internet+
Authors: Cui Guangying , Hu Jiahao
Published: December 2018

Blended learning emphasizes the role of computer‐based technologies in learning how to develop writing skills. Through BL, learners not only control the learning speed, but also do not suffer from the time restrictions of classroom interaction. Teaching and learning take place in both on-campus and online setting and various ways are offered to communicate with each other, either synchronously or asynchronously. Compared to paper teaching documents, the electronic resources are easier for the teachers to keep in order. On the other hand, blended learning leaves a significant role for students’ classroom learning. The effect of BL in developing writing skills has been done through a half-year empirical study. Over the period of half a year, the students’ writing skills have been tracked through interviews, learning contracts and teacher observations. The empirical application illustrates the features and advantages of BL approach.
A Kite Simulator Based on Aerodynamic Model
Authors: Kangl Lei , Liang JianZhe , Wang CaiLing
Published: December 2018

Kite simulator is important for training air borne wind energy controllers. A kite model based on aerodynamics and ordinary differential equation has been proposed to calculate kites’ trajectory in the air. A constant problem solver has also been developed to study the system’s stability and cross validate the simulators behaviour. Elementary evaluation shows a typical trajectory of a kite and verifies the system’s stability.
Effect of subsurface negative segregation induced by M-EMS on componential homogeneity for bloom continuous casting
Authors: Sun Haibo , Li Liejun , Wu Xuexing , Liu Chengbin
Published: December 2018

The subsurface negative segregation behavior and its effect on componential homogeneity of as-cast bloom within a section size of 320 mm × 425 mm under different stirrer currents were investigated with the aid of numerical simulation. To this end, plant trials were conducted based on a curved bloom caster in Shaoguan steel. The results show that the minimum subsurface negative segregation degree is decreased from 0.977 to 0.858 and its corresponding location moves from 16 mm to 11.9 mm distance from strand surface as the stirrer current is increased from 100 A to 600 A. The carbon content fluctuation range of rolled product cross-section first reduces and then increases because of the integrated effects of two factors: melt temperature at the mold exit center decreases (that is, undercooling is increased), whereas the local segregation degree increases with the increase in the stirrer current. As compared to the normal M-EMS parameters (600 A/2.5 Hz), the fluctuation range of carbon content at the cross-section of rolled product is reduced from 0.038 to 0.012 wt.% under the optimized M-EMS parameters of 200 A/2.5 Hz.
Effects of chromium content on the nitrided layer of binary Fe-Cr alloys
Authors: Benrabia Nacer-Eddine , Djeghlal Mohamed-el-Amine , Barrallier Laurent
Published: December 2018

Binary alloys were gas-nitrided at a temperature of 520 °C for 70 h and with a N2/NH3 ratio of 15 to 20%. The thickness of the nitrided layers was evaluated by Vickers hardness testing. The morphology and composition of the nitrided layers were investigated by light and scanning electron microscopy (SEM). Phase depth distributions were calculated by comparison of peak intensities method, and the elemental analyses were made by EDS. Increasing chromium content increases the solubility of nitrogen in both the compound and the diffusion layers, and then their hardness. It also increases CrN amount and the surface porosities, it reduces the nitrided depth but it does not affect the thickness of the compound layer. Continuous precipitation of CrN is noted until 5%Cr. For higher chromium content, discontinuous precipitation occurs hampering the diffusion of nitrogen and coarsening the precipitates. The compromise between nitrogen diffusion and CrN growth is carried out for 3%Cr.