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A method for estimating the fresh water-salt water interface with hydraulic heads in a coastal aquif
Examining the descriptions of piezometric heads at two points in both the salt water and fresh water zones reveals that when the groundwater flow system is in steady state and satisfies the Dupuit assumption, the location of the fresh water-salt water interface in a homogeneous, isotropic, and uncon- fined coastal aquifer can be estimated based on a piezometric head of fresh water at a point in the fresh water zone (from the water table to the interface) vertically lined up with a piezometric head of salt water at a point in the salt water zone (from the interface down). Research shows that the new method is a general relation and that both the Hubbert relation describing the location of the interface and the Ghyben-Herzberg relation are special cases of this method. The method requires two piezometric wells to be close to each other and each tapping into a different zone. Measurements of piezometric heads at a well cluster consisting of piezometric wells tapping separately into fresh water and salt water zones near Beihai, China at 5-day intervals for 15 months are used to illustrate the estimation of interface location. The depth of the interface for well H5 ranges from 32 to 72 m below the sea level....
2020-07-08 08:49:41浏览：74
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Numerical Simulation and Dynamical Analysis for Low Salinity Water Lens in the Expansion Area of the
The low salinity water lenses (LSWLes) in the expansion area of the Changjiang diluted water (CDW) exist in a certain period of time in some years. The impact of realistic river runoff, ocean currents and weather conditions need to be taken into account in the dynamical analysis of LSWL, which is in need of research. In this paper, the POM-σ-z model is used to set up the numerical model for the expansion of the CDW. Then LSWL in summer 1977 is simulated, and its dynamic mechanism driven by wind, tide, river runoff and the Taiwan Warm Current is also analyzed. The simulated results indicate that the isolated LSWL detaches itself from the CDW near the river mouth, and then moves towards the northeast region outside the Changjiang Estuary. Its maintaining period is from July 26 to August 11. Its formation and development is mainly driven by two factors. One is the strong southeasterly wind lasting for ten days. The other is the vertical tidal mixing during the transition from neap tide to spring tide....
2020-07-08 08:49:41浏览：46
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Water-Saving and High-Yielding Irrigation for Lowland Rice by Controlling Limiting Values of Soil Wa
The present study investigated whether an irrigation system could be established to save water and increase grain yield to enhance water productivity by proper water management at the field level in irrigated lowland rice (Oryza sativa L.). Using two field-grown rice cultivars, two irrigation systems; conventional irrigation and water-saving irrigation, were conducted.In the water-saving irrigation system, limiting values of soil water potential related to specific growth stages were proposed as irrigation indices. Compared with conventional irrigation where drainage was in mid-season and flooded at other times,the water-saving irrigation increased grain yield by 7.4% to 11.3%, reduced irrigation water by 24.5% to 29.2%, and increased water productivity (grain yield per cubic meter of irrigation water) by 43.1% to 50.3%. The water-saving irrigation significantly increased harvest index, improved milling and appearance qualities, elevated zeatin +zeatin riboside concentrations in root bleedings and enhanced activities of sucrose synthase, adenosine diphosphate glucose pyrophosphorylase, starch synthase and starch branching enzyme in grains. Our results indicate that water-saving irrigation by controlling limiting values of soil water potential related to specific growth stages can enhance physiological activities of roots and grains,reduce water input, and increase grain yield....
2020-07-08 08:49:41浏览：42
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Orientations of special water dipoles that accelerate water molecules exiting from carbon nanotube
One-dimensional ordered water molecules entering and exiting from a carbon nanotube with an appropriate radius are studied with molecular dynamics simulations.It can be found that a water molecule near the nanotube end is more likely to be expelled from the nanotube if its dipole is almost perpendicular to the nanotube axis.The key to this observation is that those water molecules axe closer to the wall of the nanotube away from the equilibrium position of the Lennar-Jones (LJ) potential.Thus,the interaction energy for those water molecules is relatively high.There are two particular structures of the perpendicular water molecule depending on the dipole direction of the adjacent water molecule in the nanotube.Although the probabilities of these structures are quite small,their contributions to the net flux across the nanotube end are approximately equal to the predominant structures.The present findings further show the possibility of controlling the water flow by regulating the dipole directions of the water molecules inside the nanochannels....
2020-07-08 08:49:41浏览：64
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Succession of aquatic microbial communities as a result of the water quality variations in continuou
The changes of structural and functional parameters of aquatic microbial communities in continuous water on campus of Tsinghua University, China are investigated by polyurethane foam unit(PFU) method. The measured compositions of the communities include alga, protozoa, and some metazoa(such as rotifers). The measured indicators of water quality include water temperature, pH value, dissolved oxygen(DO), potassium permanganate index(CODMn), total nitrogen(TN), total phosphorus(TP) and chlorophyll-a(Chla). The trophic level, expressed by the trophic level indices(TLIc), is assessed with analytic hierarchy process and principal component analysis(AHP-PCA) method. The changing trends of the structural and functional parameters of aquatic microbial communities, such as Margalef index of diversity(D), Shannon-weaver index of diversity (H), Heterotropy index(HI), number of species when the colonization gets equilibrium(Seq), colonizing speed constant(G) and time spent when 90 percent of Seq colonized in PFU(T90%), are also analyzed. The experimental results showed the succession of aquatic microbial communities along the water flow is consistent with the water quality changes, so the parameters of microbial community can reflect the changes of water quality from the ecological view....
2020-07-08 08:49:41浏览：58
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Establishment of water quality index (Na+, Ca2+) for purified water reused to zinc electrolysis proc
The effects of Na+ and Ca2+ in the purified water on the conductivity of zinc electrolyte and the current efficiency of zinc electrolysis were studied by the alternating current bridge method and the simulated electrolysis experiments, and the water quality index of reused water was established. The results show that the conductivity of the solution and the current efficiency decrease as these two kinds of positive ions are added in the electrolyte. The effect of Ca2+ is much more remarkable than that of Na+. ρ(Na+)≤ 8 g/L and ρ(Ca2+)≤20 mg/L are the quality indexes in the zinc electrolysis process and the concentrations of Na+ and Ca2+ in the purified water reused to the process should be less than the limited values, i.e. the water quality index of the purified water should be controlled by its reused amount....
2020-07-08 08:49:41浏览：46
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THE BALANCE BETWEEN SUPPLY AND DEMAND OF WATER RESOURCES AND THE WATER-SAVING POTENTIAL FOR AGRICULT
The Hexi Corridor is an important base of agriculture development in Northwest China. According to re-cent statistics, there are 65.94 × 108m3 of water resources available in the Hexi Corridor. At present, net consumption indevelopment and utilization is 43.33 x 108m3. Water supply and demand reach a balance on the recent level of produc-tion, but loss of evaporation and evapotranspiration is as much as 25.69 × 108m3. So net use efficiency of water resourcesis 59%. Based on analyzing balance between water and land considering ecological environment at present, there existsthe serious water shortage in the Shiyang River system where irrigation lands have overloaded. There is a comparative bal-ance between supply and demand of water resource in the Heihe River system; and the Sule River system has some sur-plus water to extend irrigation land. Use of agriculture water accounts for 83.3% and ecological forest and grass for6. 9%. The Hexi Corridor still has a great potential for water saving in agriculture production. Water-saving efficiency ofirrigation is about 10% by using such traditional technologies as furrow and border-dike irrigation and small check irriga-tion, and water-saving with plastic film cover and techniques of advanced sprinkler and drip/micro irrigation etc. cansave more than 60% of irrigated water. Incremental irrigation area for water-saving potential in the Hexi Corridor hasbeen estimated as 56% - 197% to original irrigation area. So the second water sources can be developed from water sav-ing agriculture in the Hexi Corridor under Development of the Western Part of China in large scale. This potential can berealized step by step through developing the water-saving measures, improving the ecological condition of oasis agricul-ture, and optimizing allocation of water resources in three river systems....
2020-07-08 08:49:41浏览：65
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Estrogen-related receptor γ disruption of source water and drinking water treatment processes extrac
Environmental chemicals in drinking water can impact human health through nuclear receptors.Additionally,estrogen-related receptors(ERRs)are vulnerable to endocrine-disrupting effects.To date,however,ERR disruption of drinking water potency has not been reported.We used ERRγ two-hybrid yeast assay to screen ERRy disrupting activities in a drinking water treatment plant(DWTP)located in north China and in source water from a reservoir,focusing on agonistic,antagonistic,and inverse agonistic activity to 4-hydroxytamoxifen(4-OHT).Water treatment processes in the DWTP consisted of pre-chlorination,coagulation,coal and sand filtration,activated carbon filtration,and secondary chlorination processes.Samples were extracted by solid phase extraction.Results showed that ERRγ antagonistic activities were found in all sample extracts,but agonistic and inverse agonistic activity to 4-OHT was not found.When calibrated with the toxic equivalent of 4-OHT,antagonistic effluent effects ranged from 3.4 to 33.1 μg/L.In the treatment processes,secondary chlorination was effective in removing ERRy antagonists,but the coagulation process led to significantly increased ERRγ antagonistic activity.The drinking water treatment processes removed 73.5% of ERRγ antagonists.To our knowledge,the occurrence of ERRγ disruption activities on source and drinking water in vitro had not been reported previously.It is vital,therefore,to increase our understanding of ERRy disrupting activities in drinking water....
2020-07-08 08:49:41浏览：49
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WATER QUALITY MODELING AND POLLUTION CONTROL FOR THE EASTERN ROUTE OF SOUTH TO NORTH WATER TRANSFER
South to North Water Transfer Project in China is the largest project over centuries to solve the water shortage problem in vast areas of northern China. It comprises of three routes: the eastern, central and western route and this study mainly focused on the eastern route. As water quality is the key factor for the eastern route, this paper examined the main factors influencing water quality of the main route south of the Yellow River, by investigating the point source, non-point source (diffusive source) and internal source pollutions along the main eastern route and in its drainage basins, and assessing the current water quality in the waterways. According to the complicated and combined systems of rivers and lakes in this route, one-dimensional water quantity and quality model for rivers and two-dimensional model for lakes were developed to simulate the hydrodynamic and pollutant transport processes. The numerical method and model algorithm were described. The values of model parameters were estimated by using field-monitoring data along the main route and the inverse modeling technique. Established models were employed to predict the degradations of CODMn and NH4+-N in the main stream, under the conditions of current pollution loads and different hydrologic conditions. Schemes were present for controlling total quantities of pollutants from point source and non-point source along the main route to secure water quality for the eastern route....
2020-07-08 08:49:41浏览：55
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Factors Influencing the Iterative Accuracy of Ground Water Level in Forecasting the Water Burst of D
The purpose of this paper is to discuss the influential factors of iteration accuracy when we use iteration to determine the numerical model for predicting water yield of deep drawdown mines and calculating the groundwater level. The relationship among the calculation error of groundwater level, the pumping rate, the limit of iteration convergence error, the calculation time, and the aquifer parameters were discussed by using an ideal model. Finally, the water yield of Dianzi iron mine was predicted using the testified numerical model. It is indicated that the calculation error of groundwater level is related to the limit of iteration convergence error, the calculation time and the aquifer parameters, but not to the pumping rate and the variation of groundwater level....
2020-07-08 08:49:41浏览：43
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Effects of Tillage Practices on Water Consumption, Water Use Efifciency and Grain Yield in Wheat Fie
Water shortage is a serious issue threatening the sustainable development of agriculture in the North China Plain, with the winter wheat (Triticum aestivum L.) as its largest water-consuming crop. The effects of tillage practices on the water consumption and water use efifciency (WUE) of wheat under high-yield conditions using supplemental irrigation based on testing soil moisture dynamic change were examined in this study. This experiment was conducted from 2007 to 2010, with ifve tillage practice treatments, namely, strip rotary tillage (SR), strip rotary tillage after subsoiling (SRS), rotary tillage (R), rotary tillage after subsoiling (RS), and plowing tillage (P). The results showed that in the SRS and RS treatments the total water and soil water consumptions were 11.81, 25.18%and 12.16, 14.75%higher than those in SR and R treatments, respectively. The lowest ratio of irrigation consumption to total water consumption in the SRS treatment was 18.53 and 21.88%for the 2008-2009 and 2009-2010 growing seasons, respectively. However, the highest percentage of water consumption was found in the SRS treatment from anthesis to maturity. No signiifcant difference was found between the WUE of the lfag leaf at the later iflling stage in the SRS and RS treatments, but the lfag leaf WUE at these stages were higher than those of other treatments. The SRS and RS treatments exhibited the highest grain yield (9 573.76 and 9 507.49 kg ha-1 for 3-yr average) with no signiifcant difference between the two treatments, followed by P, R and SR treatments. But the SRS treatment had the highest WUE. Thus, the 1-yr subsoiling tillage, plus 2 yr of strip rotary planting operation may be an efifcient measure to increase wheat yield and WUE....
2020-07-08 08:49:41浏览：55
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Multivariate analysis of surface water quality in the Three Gorges area of China and implications fo
Multivariate statistical techniques,cluster analysis,non-parametric tests,and factor analysis were applied to analyze a water quality dataset including 13 parameters at 37 sites of the Three Gorges area,China,from 2003-2008 to investigate spatio-temporal variations and identify potential pollution sources.Using cluster analysis,the twelve months of the year were classified into three periods of lowflow (LF),normal-flow (NF),and high-flow (HF); and the 37 monitoring sites were divided into low pollution (LP),moderate pollution (MP),and high pollution (HP).Dissolved oxygen (DO),potassium permanganate index (CODMn),and ammonia-nitrogen (NH4+-N)were identified as significant variables affecting temporal and spatial variations by non-parametric tests.Factor analysis identified that the major pollutants in the HP region were organic matters and nutrients during NF,heavy metals during LF,and petroleum during HF.In the MP region,the identified pollutants primarily included organic matter and heavy metals year-around,while in the LP region,organic pollution was significant during both NF and HF,and nutrient and heavy metal levels were high during both LF and HF.The main sources of pollution came from domestic wastewater and agricultural activities and runoff; however,they contributed differently to each region in regards to pollution levels.For the HP region,inputs from wastewater treatment plants were significant; but for MP and LP regions,water pollution was more likely from the combined effects of agriculture,domestic wastewater,and chemical industry.These results provide fundamental information for developing better water pollution control strategies for the Three Gorges area....
2020-07-08 08:49:41浏览：59
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A Novel Zn(Ⅱ) Complex with 1D Supramolecular Water Tape Formed by Cyclic Tetrameric Water Clusters
A new mixed-ligand Zn(Ⅱ) complex,[Zn(4,4'-bipy)2(H2O)4]·2ANS·6H2O (1,4,4'-bipy = 4,4'-bipyridine,HANS = 2-aminonaphthalene-l-sulfonic acid),has been isolated and structurally characterized by single-crystal X-ray diffraction,FT-IR spectrum,TG and elemental analysis.It crystallizes in the monoclinic system,space group P21/c with a = 12.4852(8),b =18.3163(12),c = 10.9707(7) (A),β = 114.2600(10)°,V = 2287.3(3) (A)3,Dc = 1.455 g/cm3,Mr =1002.37,Z = 2,F(000) = 1048,μ = 0.704 mm-1,the final R = 0.0408 and wR = 0.962 for 4029observed reflections with Ⅰ＞ 2σ(Ⅰ).Interestingly,an unusual one-dimensional (1D) water tape with cyclic tetrameric water clusters can be observed in 1,which are furzher trapped via Zn-O coordination bonds exhibiting a 2D Zn(Ⅱ)-water layer.These 2D Zn(Ⅱ)-water layers are stacked together into a 3D interdigitated supramolecular architecture via weak π…π interactions,in which free ANS anions are tightly filled by hydrogen-bonding interactions.Thus,π…π and classical hydrogen-bonding interactions are found as main driving forces to stabilize the 2D Zn(Ⅱ)-water layers....
2020-07-08 08:49:41浏览：60
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Pediatric burns due to hot water from water dispenser: a neglected issue that should be highly conce
Background More and more Chinese drink hot water from water dispensers while many children were scalded due to this change.The present study aimed to propose a feasible strategy for prevention.Methods A retrospective study was conducted for all water dispensers related pediatric burns admitted to Changhai Hospital from January 2005 to December 2009.Results The number of new cases and incidences of pediatric burns due to hot water from water dispensers was significantly increasing year after year.In the total 238 involved cases,175 cases happened on males and 78.9％ were at the age of 1-4 years.The burn areas were mainly located in upper extremities.All water dispensers in the surveyed families had no isolate protection devices and 85.2％ of their locations were easy for children to reach.Nearly half of the children were in the same room with their guardians when injured.Total 196 burned children were playing the taps of water dispensers before injured,unfortunately,80.6％ of them have not been stopped until burned.Conclusion As the kind of bums is quite serious and with bad outcome,some recommendations should be followed,such as buying water dispensers with protection devices,keeping children from touching them and so on....
2020-07-08 08:49:41浏览：43
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Integrated Water and CGE Model of the Impacts of Water Policy on the Beijing's Economy and Outp
The article used general equilibrium model to analyze the change of gross domestic product and industry output affected by water resources policies in Beijing City by using GEMPACK soft tool.The article researches on rules of water supply and demand,evaluating water resources,building water resources input and output table,establishing water computable general equilibrium model and stimulating water policy.The stimulation gives a scenario that increases water price by 10%.The result shows the following aspects.First,water resources policy infects gross domestic product and industry output in different ways.There are different behaviors in different industries as to the water policy.Agriculture industry has the same tendency as water price change and it has more sensitive to water quantity than to water price.For basic energy industries such as oil and chemistry and gas,they show diversity tendency.As to some high water consumer industry such as paper and textile etc.,water resource economic policy can infect them greatly and can promote them to accomplish more water-saving technology.Waste water and construction and service industries show the same tendency as to water policy.Second,government should pay more attention to water resource policy by macro economic administration.The simulation also shows that the output and supply and consumer price change more than expect as to water policy in a free market economic in water industry.So as to a government policy maker,one should be more carefully and prepare suitable forecast and plan to water policy and its negative impact....
2020-07-08 08:49:41浏览：46
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