-
Detailed investigation on single water molecule entering carbon nanotubes
The behavior of a water molecule entering carbon nanotubes (CNTs) is studied.The Lennard-Jones potential function together with the continuum approximation is used to obtain the van der Waals interaction between a single-walled CNT (SWCNT) and a single water molecule.Three orientations are chosen for the water molecule as the center of mass is on the axis of nanotube.Extensive studies on the variations of force,energy,and velocity distributions are performed by varying the nanotube radius and the orientations of the water molecule.The force and energy distributions are validated by those obtained from molecular dynamics (MD) simulations.The acceptance radius of the nanotube for sucking the water molecule inside is derived,in which the limit of the radius is specified so that the nanotube is favorable to absorb the water molecule.The velocities of a single water molecule entering CNTs are calculated and the maximum entrance and the interior velocity for different orientations are assigned and compared....
2020-07-08 21:52:19浏览：46
查看 -
Theoretical analysis on water-inrush mechanism of concealed collapse pillars in floor
In order to study the water-inrush mechanism of concealed collapse pillars from the mechanical view,a mechanical model for water-inrush of collapse pillars has been established based on thick plate theory of elastic mechanics in this paper. By solving this model the deformation of water-resistant rock strata under the action of water pressure and the expression of critical water pressure for collapse pillar waterinrush have been obtained The research results indicate that: the boundary conditions and strength of water-resistant strata play important roles in influencing water-inrush of collapse pillars. The critical water-inrush pressure is determined by both relative thickness and absolute thickness of water-resistant strata....
2020-07-08 21:52:19浏览：60
查看 -
Nonlinear Dynamic Characteristic Analysis of the Shaft System in Water Turbine Generator Set
A 3D finite element vibration model of water turbine generator set is constructed considering the coupling with hydropower house foundation. The method of determining guide bearing dynamic characteristic coefficients according to the swing of the shaft is proposed, which can be used for studying the self-vibration characteristic and stability of the water turbine generator set. The method fully considers the complex supporting boundary and loading conditions; especially the nonlinear variation of guide bearing dynamic characteristic coefficients and the coupling effect of the whole power-house foundation. The swing and critical rotating speed of an actual generator set shaft system are calculated. The simulated results of the generator set indicate that the coupling vibration model and calculation method presented in this paper are suitable for stability analysis of the water turbine generator set....
2020-07-08 21:52:19浏览：61
查看 -
A Comparative Study of CART and PTM for Modelling Water Age
CART (Constituent-oriented age and residence time theory) and PTM (Particle-tracking method) are two widely used numerical methods to calculate water age. These two methods are essentially equivalent in theory but their results may be different in practice. The difference of the two methods was evaluated by applying them to calculate water age in an idealized one-dimensional domain. The model results by the two methods are consistent with each other in the case with either spatially uniform flow field or spatially uniform diffusion coefficient. If we allow the spatial variation in horizontal diffusion, a term called pseudo displacement arising from the spatial variation of diffusion coefficient likely plays an important role for the PTM to obtain accurate water age. In particular, if the water particle is released at a place where the diffusion is not the weakest, the water age calculated by the PTM without pseudo displacement is much larger than that by the CART. This suggests that the pseudo displacement cannot be neglected in the PTM to calculate water age in a realistic ocean. As an example, we present its potential importance in the Bohai Sea where the diffusion coefficient varies spatially and greatly....
2020-07-08 21:52:19浏览：43
查看 -
Formation of infinite 2D water layers in a crystal host
A self-assembled, (H2O)38 cluster stabilized by a mono-nuclear copper(Ⅱ) complex 1 namely {[Cu(phen)2(CO3)].7H2O} is characterized by X-ray diffraction studies. The adjacent (H2O)38 clusters connect together resulting in an infinite 2D water layer structure. The water morphology is stable at room temperature, but upon thermal decomposition, the water loss is irreversible....
2020-07-08 21:52:19浏览：44
查看 -
AHP Comprehensive Evaluation on Sustainable Utilization of Water Resources in Hengshui City, China
In order to investigate the sustainable utilization of water resources in Hengshui City, quantitative analysis and comprehensive evaluation on 15 indexes of Hengshui City, such as the perspectives of social and economic devel-opment condition, water resource condition, environment condition, development and utilization of water resources, were conducted by using the analytic hierarchy process(AHP) method from 2004 to 2008. Although the sustainable utilization has been growing from 2004 to 2008, the situation and environment of water resources were not optimistic because of the severe water shortage in Hengshui. In the future, improving the supply capacity is the key target for promoting sustainable utilization of water resources....
2020-07-08 21:52:19浏览：50
查看 -
Effect of Perched Water Tables on Aluminosilicate Stability and Soil Genesis
The mineral stability and solute activities of soil solution extracted from selected horizons of seven studied
pedons of Alfisols in Kentucky, USA, and the relationship between distribution of iron-manganese concretions
and the restrictive layers were investigated. The results showed that the genesis and development of these
soils and mineral weathering trends were strongly influenced by the depth of bedrock and the presence of
perched water tables at lithic (limestone) interfaces due to the dissolution and buffering effect of limestone
bedrock. The extractable Mg/Ca ratio as depth function and soil depth above bedrock could be used as
indices of weathering and degree of soil development. Maximum iron-manganese concretion accumulation
was found to occur in the horizon overlying clay horizon (＞40% clay) with a sharp increase in clay content
(＞ 10%), which suggested that zones of Fe-Mn concretion accumulation in soils of the Inner Bluegrass Region
appeared to be a sensitive genetic indicator of argillic horizons with restrictive permeability....2020-07-08 21:52:19浏览：57
查看 -
Ordinary Toxicity of Chlorine Dioxide and By-products Chlorite and Chlorate in Water
Acute toxicity and accumulated toxicity of chlorine dioxide (C1O2) and by-products chlorite ( C1O-2 ) and chlorate (C1O-3) in water acted on mice are studied by the method of Horn and accumulation coefficient.Subchronic toxicity of the mixture of C1O2 and C1O-2 and ClO-3 in water acted on rat is studied though feeding test for 90 days, including statistical analysis of variance on weight gaining, food utilization efficiency, index of blood and serum, liver (or kidney)to body weight ratio, and histopathological examination on liver and kidney. The results show that aqueous solution of C1O2, NaC1O2 and NaC1O3 (with the concentration of 276. 5 mg/L, 200 mg/L and 200 mg/L respectively) and the mixed aqueous solution of C1O2 with the concentration of 553 mg/L are actually non poisonous, and non-cumulative aqueous solution as well....
2020-07-08 21:52:19浏览：70
查看 -
Two-dimensional numerical algorithm for water qualitymodeling in the topographically complicated riv
In this paper, a two-dimensional numerical calculation algorithm for the water quality modeling in the Hengyang City section of the Xiangjiang River is researched considering the effect of the Dayuandu navigational key project. The research fiver is winding and has two branches resulted from an isle. The numerical calculation algorithm for the water quality modeling is set up on the basis of applying topographic map of the river course and the finite element method. The calculation result for the water quality modeling includes the concentration fields for various pollutants. The numerical calculation algorithm for the water quality modeling set up in this paper can be applied to shallow fiver with similar topographically complicated river course....
2020-07-08 21:52:19浏览：31
查看 -
Preliminary study on interaction of water mist with diffusion flame of liquid fuels
The chemical and physical interaction mechanisms of the water mist with diffusion flame of liquid fuels are investigated.The difference of the thermograms and the thermal field isograms between ethanol flame and kerosene flame with the water mist application is explained. With the water mist application, the differences between ethanol and kerosene in heat release rate, O2 and CO concentrations of their combustion products, and the temperature of their smoke are analyzed. At the same time, the interaction mechanism of the water mist with diffusion flame is presented and their relationship to the fuel species and to the concentration of water mist is described....
2020-07-08 21:52:19浏览：46
查看 -
Empirical formula for wave length of ocean wave in finite depth water
In this paper, function characteristics of dispersion of ocean wave in finite depth water were analyzed systematically. The functional form of the fitting function is reasonably proposed, in which the parameters are optimally determined by the least square method (LSM). For infinitely deep and extremely shallow water,the fitting function fits strictly the dispersion to be fitted. A new technique is presented in application of LSM.An empirical formula with maximum error of less than 0.5% for computing wavelength in finite depth water is presented for practical applications....
2020-07-08 21:52:19浏览：30
查看 -
Application of SEDEA to evaluation of degree of harmony between water resources and economic develop
This paper introduces the method of data envelopment analysis (DEA) for evaluation of the degree of harmony between water resources and economic development of the water conservancy area of China's South-to-North Water Diversion Project (SNWDP). For this evaluation, a super-efficiency DEA (SEDEA) model was developed based on the super-efficiency method. To verify the applicability of the SEDEA model, both the SEDEA model and a normal-efficiency DEA (NEDEA) model were used to evaluate the degree of harmony between water resources and economic development of typical cities in the SNWDP water conservancy area. The results show that the SEDEA model ranks the degree of harmony of typical cities more efficiently than the NEDEA model, and thus can better evaluate the degree of harmony between water resources and economic development of different cities than the NEDEA model.Furthermore, the SEDEA model can be applied as an operational research tool in regional water resources management....
2020-07-08 21:52:19浏览：61
查看 -
Node ordinal encoded genetic algorithm for the optimal allocation of water resources
A new method, node ordinal encoded genetic algorithm (NOEGA), is proposed for solving water resources optimal allocation problems, in which the capacity of water resources is split into a number of smaller parts so that successive operations can be overlapped. Our objective is to maximize the whole benefit function. To overcome the "dimensionality and algorithm complexity curse" while searching for solutions and looking for an optimal solution, the operations of one-point crossover operator, gene exchange operator, gene random operator, gene shift operator and node ordinal strings are established. It is proved to be an effective optimal method in searching for global solutions. The NOEGA does not need a diversity of initial population, and it does not have the problem of immature convergence. The results of two cases show that using NOEGA to solve the optimal allocation model is very efficient and robust. In addition, the algorithm complexity of NOEGA is discussed....
2020-07-08 21:52:19浏览：73
查看 -
Nickel Chloride Promoted Glaser Coupling Reaction in Hot Water
A Glaser coupling reaction of terminal alkynes in the presence of nickel chloride without any organics and bases in hot water has been developed, which produces the corresponding homo-coupling products in good yields....
2020-07-08 21:52:19浏览：36
查看 -
SAFETY ANALYSIS OF WATER RESOURCES AND ECG-ENVIRONMENT IN SHIYANG RIVER BASIN
The research on the present situation of soil and water development and utilization in Shiyang River Basin shows that water resources and eco-environment situation in this area are near the edge of collapse. Since the water crises occurred in the 1970s, problems caused by continuous decrease of water resources have been becoming serious year by year and eco-environment crisis occurred as a consequence. Up to now, 10 380ha of irrigated lands have been abandoned due to sand coverage and water shortage in the basin. Ground water was over exploded in Wuwei and Minqin because of water shortage. Ground water table in many places dropped under 5m (which is the ecology water table level), thus about 3000ha ofElaeagnus angustifolia forest come to dead and another 5800ha become feeble, and wind-driff sand near the oasis become alive. According to the current situation, if water utilization scope was not enlarged, a water transfer volume of 600×106m3/a from other areas will be suitable to keep water resources and eco-environment safety in the basin, and also 70× 106m3/a will be left as spare water. Under this condition the water resources and eco-environment of the basin can reach the critical safety line of 2.032× 109m3/a; or if 180× 106m3 of water can be transferred from other areas, the water resources can reach the safety warning line of 1.732× 109m3/a....
2020-07-08 21:52:19浏览：37
查看
