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NUMERICAL SIMULATION OF ROCK BREAKING MECHANISM WITH HIGH-PRESSURE WATER JET
Based on the analysis of experimental results, the rock damage model and the damage coupling model suitable for the whole rock breaking process with water jet were established with continuous damage mechanics and micro damage mechanics, and the numerical method was developed with continuum mechanics and the FEM theory. The rock breaking mechanism with water jet was studied systematically with numerical simulation for the first time in the field of water-jet rock breaking. The numerical results agree with the experimental ones which shows that the presented method is reasonable and can reflect the reality of water-jet rock breaking. The conclusion can be applied in practice....
2020-07-08 21:52:19浏览：63
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An Analytical Solution for One-Dimensional Water Infiltration and Redistribution in Unsaturated Soil
Soil infiltration and redistribution are important processes in field water cycle, and it is necessary to develop a simple model to describe the processes. In this study, an algebraic solution for one-dimensional water infiltration and redistribution without evaporation in unsaturated soil was developed based on Richards equation. The algebraic solution had three parameters, namely, the saturated water conductivity, the comprehensive shape coefficient of the soil water content distribution, and the soil suction allocation coefficient. To analyze the physical features of these parameters, a relationship between the Green-Ampt model and the algebraic solution was established. The three parameters were estimated based on experimental observations, whereas the soil water content and the water infiltration duration were calculated using the algebraic solution. The calculated soil water content and infiltration duration were compared with the experimental observations, and the results indicated that the algebraic solution accurately described the unsaturated soil water flow processes....
2020-07-08 21:52:19浏览：36
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Seismic Response Analysis of Portal Water Injection Sheet Pile
To further the study on the newly developed portal water injection sheet pile under static loads, in this paper, by adopting the nonlinear calculation module of FEM software ANSYS, a model for the interaction between the soil and the sheet piles is set up,and the seismic response analysis for this type of space-retaining structure is performed. The effects of the embedded depth and the distance between the front pile and the back pile on the dynamic characteristics of the portal water injection sheet pile are studied....
2020-07-08 21:52:19浏览：56
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Monthly Water Budget of Small Basin in Northern of Loess Plateau,China
The objective of this study was to analyze the water budget of a small basin in the northern of Loess Plateau. A small basin, Liudaogou in the northern Loess Plateau was chosen as the study area. The numerical calculation of surface runoff was applied to results of the field survey, and components of monthly water budget were estimated. The unit area of 1 km...
2020-07-08 21:52:19浏览：59
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INFLUENCE OF LONG AND DEEPLY-BURIED DIVERSION TUNNELS ON THE WATER TEMPERATURE
A 3-D temperature model for diversion tunnel was developed by combining k-ε model and energy transport equation. The actual geometry data of the tunnel was used to construct a three-dimensional computational domain including the concrete lining. As the interaction between temperature and velocity fields can be taken into account, the model can be employed to accurately simulate the temperature and velocity field. The model was validated with the field data observed in the diversion tunnel of the Nanya River. The water temperature of the diversion tunnel of the Second Jinping Cascade Hydropower Station to be built was predicted. It is shown that the temperature increase is not observable due to the large diameter of the tunnel, the big flow rate and the short contact time. The result can provide scientific foundation or reference for the design of hydropower station, and protection strategy of aquatic organisms and aquatic ecosystem....
2020-07-08 21:52:19浏览：55
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Effect of Graphite Nodule Diameter on Water Embrittlement of Austempered Ductile Iron
Effects of graphite nodule diameter on the water embrittlement of austempered ductile iron (ADI) is studied. The water embrittlement mechanism is discussed. Due to water adhesion, local embrittlement occurs on the surface of ADI specimen, resulting in early fracture and significant reduction in tensile strength and elongation. The water embrittlement is the cracking of stress induced martensite formed during tensile deformation caused by hydrogen diffusion decomposed from water and as a result tensile strength and elongation of ADI are remarkably reduced. The segregation of alloying elements in ductile iron is weakened with decreasing nodule diameter, reducing the residual austenite in grain boundaries, then decreasing the amount of stress induced martensite during tensile plastic deformation and finally restraining ADI water embrittlement....
2020-07-08 21:52:19浏览：58
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Water Transport Models of Moisture Absorption and Sweat Discharge Yarns
An important property of moisture absorption and sweat discharge yams is their water transport property. In the paper, two water transport models of moisture absorption and sweat discharge yams were developed to investigate the influence factors on their wicking rate. In parallel Column Pores Model, wicking rate is determined by the equivalent capillary radius R and length of the capillary tube L. In Pellets Accumulation Model, wicking rate is decided by the capillary radius r and length of the fiber unit assemble L0....
2020-07-08 21:52:19浏览：64
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Study on numerical simulation to water lowering in an open coal mine digging
In view of the situation of excavation of open coal mine for the underground water disaster, we should carry out simulation studies for the numerical value of the water lowering project and improve the accuracy and the level of the water lowering project. On the basis of the hydrological geological conditions of certain open mine digging, a more reasonable seepage numerical model was built according to MODFLOW. It was simulated in advance that the process of the confined water level descending with the time, and combining with the actual observations to test the correctness of the model. The calculation showed that the results coincided well with the results of actual measurement. Based on this, different water lowering numerical simulations were built for the open coal mine digging. It could be simulated and forecast that the changes of the groundwater level in drainage process within and outside the mine pit, and it was quantitatively assessed that the possible water lowering result of the opencast water drainage process, which provide an important basis for the actual water lowering project and the possible project disposal....
2020-07-08 21:52:19浏览：41
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Effect of water on the performance of Pd-ZSM-5 catalysts for the combustion of methane
Palladium-based catalysts were prepared using impregnation (I) and ion-exchange method (E) with ZSM-5 as support. Pd-ZSM-5(I) and Pd-ZSM-5(E) catalysts presented the high activity for the combustion of methane. The order of activity was consistent with Br0nsted acidity of the catalysts: Pd-ZSM-5(I)＞Pd-ZSM-5(E). It was shown by FT-IR that methane was adsorbed on the acidic bridging hydroxyl groups of ZSM-5-supported Pd catalysts. The effect of water on the activity of Pd-ZSM-5 was investigated. The inhibition effect of water on the conversion of methane was observed. However, water promoted the stability of Pd-ZSM-5 obviously during extended time periods. XPS measurement showed that Pd/Si ratio near the surface of Pd-ZSM-5(E) decreased more pronouncedly with time in dry stream than that of Pd-ZSM-5(I), this is attributed to the dispersion of Pd into the micropores. The addition of water, however, retarded Pd dispersion. And high partial pressure of methane reduced this effect of water vapor. The decrease in activity during the stability test can be explained on the basis of the reduction of Pd/Si ratio....
2020-07-08 21:52:19浏览：48
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Improving methane storage on wet activated carbons at various amounts of water
Different mesoporous activated carbons were prepared by both chemical and physical activation processes and were examined for methane uptake in the presence of water.Methane isotherms were obtained at wet condition by wetting samples with water at mass ratio of water/carbon (R) close to 1.0.To compare,the amount of methane storage were also measured at dry situation.The maximum amount of methane stored was attained as 237 WV at R=1.0 by hydrate formation at the methane critical pressure.In the next step,mass ratios of water/carbon were changed to investigate various amount of water for methane storage enhancement.Two other values of mass ratio of water/carbon ( R =0.8 and 1.4 ) were selected and methane isotherms were obtained at the same conditions.Maximum values of 210 and 248 V/V were reached for methane storage,respectively.It was also observed that,in the pressure range lower than hydrate pressure,by increasing water ratio the hydrate formation pressure was decreased and methane uptake was much less than that of dry condition due to pore filling by water....
2020-07-08 21:52:19浏览：66
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A Numerical Study of Water Circulation in A Thermally Stratified Embayment
Princeton Ocean Model is used to study the response of Jervis Bay, NSW, Australia, to the local wind and remote shelf coastal trapped wave (CTW) forcings in summer seasons when the water column is stratified by the water temperature. The study has revealed that the response of bay to the wind forcing is the generation of the wind driven currents and the internal Kelvin waves (IKW). However, both temperature and flow sub-inertial oscillations in the bay are weaker than those from the observations and the correlation between the modeled and observed low frequency currents is low. In response to the forcing of CTWs on the adjacent shelf, IKWs are also established in the bay and amplitudes of sub-inertial oscillations of temperature and currents agree better with the observations. It can be concluded that sub-inertial baroclinic flows in the bay is dominantly forced by remote CTW on the shelf adjacent to Jervis Bay during thermally stratified summer seasons....
2020-07-08 21:52:19浏览：56
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Study on Entropy Weight Coefficient Method and Application for Water Quality Evaluation
In order to evaluate the quality of water environment, the conception of entropy is applied in information science, and the entropy weight model is built to evaluate comprehensively water quality. The indexes weights of water quality are determined by value of entropy. This kind of method is applied on evaluating water quality in the new water to be built. The result shows that the water quality in it which supply water is between grade Ⅲ and Ⅳ, and the result is similar to that of gray related method....
2020-07-08 21:52:19浏览：61
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Characteristics of the main polluting trace elements in the water environment of mining subsidence p
Mining subsidence pools are water bodies formed by soil subsidence near mines. We studied the impact the surrounding coal production activities and power plants have on these waters by measuring the concentrations of harmful trace elements in these waters. The concentration of the four elements F, Hg, Se and As increased by 0.92%, 0.78%, 0.70% and 0.81%, respectively, in the Datong mining subsidence pool from November 2004 to November 2006. The four elements increased by 1.58%, 1.23%, 1.08% and 0.92%, respectively, in the Xie'er mining subsidence pool and 1.16%, 1.06%, 1.02% and 1.01%, respectively, in the Pansan mining subsidence pool over the same time period. The absolute levels of F, Hg, Se and As in the pool are related to the background levels of the elements. A close relationship between nearby coal mines and power plants and increasing levels of the measured elements is noted....
2020-07-08 21:52:19浏览：45
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Tensile Behavior of the Flax/Polyester Composites after Water Treatment
With flax fabric as the reinforcement and unsaturated polyester as the matrix,composites of two,three,and four layers were fabricated respectively by the vacuum assisted resin infusion(VARI)technique.Tensile strength of the composites after being saturated in the water for different durations was tested.The tensile strength of the two-layer composites was decreased after being soaked in the water for two,three,and six month,respectively.For the three and four layers specimens,the tensile strength was decreased initially with water treatment.After reaching the minimum,the tensile strength was increased.Scanning electron microscopy(SEM)confirmed that it might be contributed to the thickness of the two-layer composites.The thinner specimen is easier to be damaged by the penetrated moisture owing to the delamination between the fiber and the matrix after water immersion.For the three and four layers specimens,their contradictory tensile strength suggests that the thicker specimen can delay the moisture permeation and is of better water durability....
2020-07-08 21:52:19浏览：25
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Effects of combinatorial water atomization on microstructures and properties of Cu-Sn powder
A couple of additional cooling nozzles were assembled under traditional atomization nozzles in order to improve the process and produce the powder with fine microstructure and low oxygen. The influence of the process parameters on the properties of the powder was investigated. The results show that finer powders with lower oxygen content and more irregular shape can be achieved by combinatorial atomizing process comparing with normal one under the same atomizing pressure....
2020-07-08 21:52:19浏览：46
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