Experimental investigation of clam water impact on flatted-bottom seafloor mining tool简

A test rig for constant velocity water entry experiments was developed that drives a flatted-bottom section attached on six degree of freedom（6-DOF） platform to enter the water vertically at near constant velocity.The experiment system,which consists of drive and actuation system,water pool,model test sections,load cell,and control system,was presented.Water entry forces of different velocities were measured during impact process,and for each test case,three runs were performed with the same motion program to check the repeatability of the force readings.The experiment results are compared with two-dimensional（2D） CFD simulation methods for flatted-bottom rigid bodies with constant entry velocity.Experimental results indicate that the impact forces mainly depend on water entry velocities.It is concluded that the feasibility and accuracy of simulation methods has been validated.     

The Influence of Free Water Content on Dielectric Properties of Alkali Active Slag Cement Paste

The dielectric performance of alkali activated slag （AAS） cement paste was investigated in the frequency range of 1 to 1000 MHz. The experimental results showed the unstable dielectric properties of harden paste were mostly influenced by the fraction of free water in paste or absorbed water from ambient, but not including hydration water and microstructure. The free water was completely eliminated by heat treatment at 105 ℃ about 4 hours, and then its dielectric loss was depressed; but with the exposure time in air increasing, the free water adsorption in ambient air made the dielectric property of harden cement paste to be bad. The temperature and relative humidity of environment was the key factors of free water adsorption; hence, if the influence of free water on dielectric constant was measured or eliminated, the cement-based materials may be applied in humidity sensitive materials or dielectric materials domains.     

An Entrapment Model of Water Flow on Fine Coal Flotation

Effect of entrapment of water flow on fine coal flotation was studied. The relation between constant of water flotation rate and flotation time was investigated and the water recycling model determined. The entrapment model of water flow about the relation between the recovery of fine particle and that of water in concentration was established. Finally, the equation about ash in fine clean coal at any time was derived by introducing a de-ashing coefficient.     

Influence of Electric Double Layer on Lubrication

A mathematical model of lubrication with the electric double layer (EDL) was put forward in order to study the influence of EDL.The lubrication tests with a composite sliding block and a disk were caried out with oleic acid used as an additive to strengthen EDL.The streaming potential and friction force were measured.The experimental results show that the EDL has an qpparent effect on the frictional force,which increases the ability of forming lubrication film.     

Geological Engineering,Civil Engineering,Traffic and Transportation Engineering Electrical capacitance volume tomography for measurement soil water infiltration in vessel experiments简

Electrical capacitance volume tomography （ECVT） is a recently-developed technique for real-time, non-invasive 3D monitoring of processes involving materials with strong contrasts in dielectric permittivity. This work is first application of the method to visualization of water flow in soil. We describe the principles behind the method, and then demonstrate its use with a simple laboratory infiltration experiment. 32 ECVT sensors were installed on the sides of an empty PVC column. Water was poured into the column at a constant rate, and ECVT data were collected every second. The column was then packed with dry sand and again supplied with water at a constant rate with data collected every second. Data were analyzed to give bulk average water contents, which proved consistent with the water supply rates. Data were also analyzed to give 3D images （216 voxels） allowing visualization of the water distribution during the experiments. Result of this work shows that water infiltration into the soil, wall flow, progress of the unstable wetting front and the final water distribution are clearly visible.     

Simulation of coupled THM process in surrounding rock mass of nuclear waste repository in argillaceous formation

To investigate and analyze the thermo-hydro-mechanical(THM) coupling phenomena of a surrounding rock mass in an argillaceous formation, a nuclear waste disposal concept in drifts was represented physically in an in-situ test way. A transversely isotropic model was employed to reproduce the whole test process numerically. Parameters of the rock mass were determined by laboratory and in-situ experiments. Based on the numerical simulation results and in-situ test data, the variation processes of pore water pressure, temperature and deformation of surrounding rock were analyzed. Both the measured data and numerical results reveal that the thermal perturbation is the principal driving force which leads to the variation of pore water pressure and deformations in the surrounding rock. The temperature, pore pressure and deformation of rock mass change rapidly at each initial heating stage with a constant heating power. The temperature field near the heater borehole is relatively steady in the subsequent stages of the heating phase. However, the pore pressure and deformation fields decrease gradually with temperature remaining unchanged condition. It also shows that a transversely isotropic model can reproduce the THM coupling effects generating in the near-field of a nuclear waste repository in an argillaceous formation.     

Model-based parameter identification of comprehensive friction behaviors for giant forging press

A new experimental apparatus was set up to investigate the actual fi-iction characteristics on the basis of speed control of the serve system.A modified friction model was proposed due to real time varying deformation resistance.The approach to identify the parameters of comprehensive friction behaviors based on the modified model was proposed and applied to the forging press.The impacts on parameters which the external load had were also investigated.The results show that friction force decreases with velocity in the low velocity regime whereas the friction force increases with the velocity in the high velocity regime under no external load.It is also shown that the Coulomb friction force,the maximum static friction force and the vicious friction coefficient change linearly with the external load taking the velocity at which the magnitude of the steady state friction force becomes minimum as the critical velocity.     

Numerical simulation of calm water entry of flatted-bottom seafloor mining tool

The hydrodynamic problem of a two-dimensional model of seafloormining tool entering still water vertically at constant speed was analyzed based on the velocity potential theory.For the assumption that the water entry occurs with very short time interval,the viscosity and gravity of fluid were neglected.Considering the characteristic shape of it,the seafloormining tool was simplified as a flat-bottom body.The governing equations were the Reynolds time-averaged equations and the k-ε model.Finite element analy...     

Experimental study on upward bubble velocity and pierce length distributions in a water model of copper converter

The upward bubble velocity and the pierce length distributions in a sectional water model of the copper converter in Guixi Smelter in Jiangxi, China, were measured using a two-contact electro-resistivity probe. In the case of using a single tuyere, the bubble velocity distribution along longitudinal direction was similar to that derived from Guassian function. Beyond the center of the longitudinal range, the bubble pierce length exhibited a sudden increase. The upward bubble velocity at a specified location could go up to meters per second. Its probability at a fixed location obeys a lognormal function; the bubble pierce length there varies bellow a few centimeters. In the case of using multi-tuyeres, the upward bubble velocity was roughly uniform right above the tuyeres and showed a slow decrease beyond this region. The bubble pierce length within both of these two regions was roughly uniform. Its average value in the former region, however, was found to be somewhat lower than that in the later.     

A Preliminary Study on 1D Numerical Experiment of Water Debris Flow in Gully

In order to improve and enhance the numerical modeling methods and its application on debris flow problems,a preliminary study has been proposed in accordance with the corrected water-sediment numerical model on the premise of revised resistance and sediment capacity equations.Firstly,an overview the recent re- search achievements on numerical simulation of debris flow has been conducted,the results shown that a gener- al numerical model for debris flow can not be existed at all because the complex rheological behavior and main evolution processes from initiation,movement to deposition with different physical mechanism.Secondly,as- suming the one-dimensional Saint-Venant equation for the approximation of water debris flow movement in the gully based on the Manning's equation for the friction slope of water debris flow,the conservation equations of mass and momentum have been solved by means of centre-difference in distance longitudinal axis of the gully and weighted coefficient in time field,the distribution of depth,velocity and scoured or deposition in each sec- tion have been obtained using a suitable sediment transport rate.The aim in this work is focus on improvement of water-sediment model to adapt debris flow numerical simulation although this result need further to analyze and discuss as far as the reliability and precision were concerned because this model proposed must have e- nough the field observational or experimental data to verify related model parameter.     

水利高校水文化断想之以水养德

校园文化在高校德育教育中具有价值导向、行为规范、品德熏陶、扬弃与创造等功能,一直以来,水利高校非常重视水文化的培育与积淀,不断提高校园文化德育教育的效益.本文从校园文化的功能切入,挖掘了水文化的内涵,引导水利高校大学生对＂水＂有更加深刻的认识,从而实现水文化德育教育效益的提高.     

水权交易水价计算方法研究

水权交易是实现水资源优化配置的有效手段,而水权交易中水价的估算是进行水权交易的重要依据.选定水资源影子价格作为水资源价值量化的手段,根据水资源影子价格静态计算模型和水资源影子价格动态可计算均衡模型,分别推导出临时性水权交易、长期限水权交易中水价的计算公式.     

基于水文循环过程的生态需水量化方法

探讨了生态需水的概念,指出生态需水量的计算应从水文循环机理入手,以确保流域生态系统维持最基本健康水平.将分布式水文模型和生态系统健康评价方法融合在一起,建立了基于流域水文循环过程的生态需水量化方法.该方法以水文循环过程作为联系各种生态系统的纽带,可反映出不同用水量对流域生态系统整体健康状况的影响,克服了传统量化方法计算交叉、重叠的缺点,使计算结果更加合理可信.     

从城市水系统浅析城市缺水原因

城市缺水严重制约了城市的可持续发展,影响了生活环境和经济发展,通过对城市水系统的分析,得出城市缺水的原因,以便于有关水管理部门借鉴,同时让城市居民了解城市缺水的原因。     

饮用水源地水资源预警系统构建探析

针对饮用水源地水量水质经常发生变化,对饮水安全造成威胁的情况,结合具体实例,开展建立饮用水源地水资源预警系统的探索与研究。通过可控制区域水位、水量、水质监测,建立自动监测信息网络,设立多种序列的预警判别规则模块,进行实时预警,以提高快速应对突发事件的处置能力,提高水资源管理水平,保障城乡供水安全。     

基于水平衡测试的火电厂水务管理与优化

通过对安徽省各电厂水平衡测试结果的分析,指出安徽区域火电厂水务管理工作的现状,总结区域内火电厂水资源利用不合理的共同之处,并针对性的提出合理的优化方案,为火电厂实施真正意义的"零排放"打下基础。     

玉环漩门二期蓄淡水库水环境现状分析及治理对策

根据近年来对玉环漩门二期蓄淡工程水体的水质监测资料分析,该水库水环境污染及富营养化状况问题严重,部分水质指标超标倍数达到数十倍,水库中的含盐量始终处于较高水平,物理指标不理想,总磷、氨氮等主要指标浓度也始终较高,据此,应加大库区水污染防治力度,完善水质监测站网,调整库区内产业结构,并实施河湖直接净化及生物一生态修复技术改善水质。     

水污染防治政策对台湾水环境可持续性的影响

回顾台湾近30年来的社会变迁及各种政策对水体水质所造成的影响。在迈入21世纪之际，提供一个可持续的水环境是大家共同的愿望，因此，如何平衡经济及科技发展与环境保护问的关系，将是推动台湾水环境可持续发展必经之途。     

中水回用于火电厂循环冷却水的技术

中水用于电厂循环冷却水的补充水,不仅可以扩大中水回用规模,而且也为电厂提供了一个水量充足的水源.针对城市污水的特点和循环冷却水的要求,提出了技术可行、可靠,且投资、运行费用较低的中水深度处理工艺.     

Impact of Untreated Sedimentation Tank Sludge Water Recycle on Water Quality During Treatment of Low Turbidity Water

The overall purpose of this research is to examine the impact of untreated sedimentation tank sludge water( USTSW) recycle on water quality during treatment of low turbidity water in coagulation—sedimentation processes. 950 m L of raw water and different concentrations of 50 m L USTSW are injected into six 1 000 m L beakers without coagulant.The results indicate that USTSW characterized as accumulated suspended solids and organic matter has active ingredients,which possess the equivalent function of coagulant. The optimal blended water turbidity is in the range of 10-20 NTU,within which USTSW recycle achieves the highest save coagulant rate. The mechanism of strengthening coagulation effect when USTSW recycle mainly depends on the chemical effect and physical effect. What is more,through scanning electron microscopy( SEM),it is found that the floc structures with USTSW recycle are more compact than those without USTSW recycle. Besides,the water quality parameters of color,NH3-N,CODMn,UV254,total aluminum,total manganese when USTSW recycle is better than the raw water without recycle,indicating that USTSW recycle can improve water quality with strengthening coagulation effect.