Papers by Keyword: Water

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Authors: Jozef Kačur, Jozef Minár
Abstract: We model the flow of the contaminated water through the porous media sample. We model the inflow of water, flux of water in the sample, flux of the contaminant in the water in the sample, adsorption of the contaminant in the sample and the outflow of the contaminated water from the sample. During the process, there appears fully saturated zone, partially saturated zone and dry zone. We consider Darcys law for flux of the water in fully saturated zone and Richards equation for flux in the partially saturated zone. Flux of the contaminant is governed by Ficks law and the adsorption of contaminant is modeled using Freundlich isotherm. Problem is solved in 1D using numerical solution based on the MOL method. Since flow of the water is independent of the contaminant, we compute separately saturation in the whole time interval and then contamination of water and adsorption of contaminant in the sample.
Authors: Deepak P. Adhikary, Hua Guo
Abstract: Simulation of mining induced rock deformation, rock fracture enhanced permeability and fluid and gas diffusion and flow process is a complex task. A new three dimensional coupled mechanical two-phase double porosity desorption and diffusion finite element code called COSFLOW has been recently developed by CSIRO Exploration and Mining to service the mining industry’s need. A unique feature of COSFLOW is the incorporation of Cosserat continuum theory in its formulation. In the Cosserat model, inter-layer interfaces (joints, bedding planes) are considered to be smeared across the mass, i.e. the effects of interfaces are incorporated implicitly in the choice of stress-strain model formulation. An important feature of the Cosserat model is that it incorporates bending rigidity of individual layers in its formulation and this makes it different from other conventional implicit models. The Cosserat continuum formulation has a major advantage over conventional continuum models in that it can efficiently simulate rock breakage and slip as well as separation along the bedding planes. Any opening/closure along a bedding plane may introduce a strong anisotropy in fluid flow properties of the porous medium. This, in turn, will impact on the fluid/gas flow behaviour of the porous medium. This paper will briefly describe the Cosserat continuum theory, the treatment of permeability changes with rock deformation and the coupling of the two-phase dual porosity fluid diffusion- flow model and present a number of examples highlighting the capability of the developed code in simulating the mining induced rock deformation, permeability changes and fluid diffusion and flow will be presented.
Authors: Fernando Herrán, Hervé Fontaine, Paola González-Aguirre, Carlos Beitia, Jim Ohlsen, Jorgen Lundgren
Abstract: In order to better understand and model the whole sorption behavior of the HF when in contact with a Cu surface inside a FOUP and thus control the related yield losses, Cu-coated wafers have been exposed to varying HF (ppbv) and H2O (% RH) airborne concentrations. These experiments have yielded a HF-Cu sorption empirical-mathematical model that may be used as an industrial tool for queue-time or fluoride surface concentration predictions. Besides, the formation of CuF2 only in case of corrosion is evidenced by the XPS measurements whereas the key role of the H2O is further confirmed by the desorption experiments. The H2O retained by the surface is actually responsible for promoting the HF adsorption/desorption onto/from Cu and enables a HF threshold concentration that separates the two well differenced uptake regimes; adsorption and corrosion.
Authors: O. Assowe, Olivier Politano, Vincent Vignal, Patrick Arnoux, B. Diawara
Abstract: The interaction of water molecules on a nickel surface was studied using ReaxFF (reactive force field) molecular dynamics. This approach was originally developed by van Duin et al. to study the hydrocarbon chemistry and the catalytic properties of organic compounds. To our knowledge, this method has not been used to study the corrosion processes of nickel exposed to water, which is what we set out to achieve in the present investigation. To do so, calculations were first performed using ReaxFF in order to reproduce certain well-known properties of pure nickel and nickel-water systems. This allowed us to study the adsorption of a single water molecule interacting with an optimized nickel surface. We also investigated the interaction of 405 molecules of water (ρ=0.99 on the (100), (110) and (111) surfaces of a single crystal of nickel at 300 K. The results show that a water bilayer is adsorbed on nickel surfaces: the first water layer is directly bonded to the surface, whereas the molecules in the first and second layers are held together by hydrogen bonds.
Authors: Eiji Watanabe, Kaori Nishizawa, Masato Tazawa
Abstract: Because bromic acid ion generated by the ozone processing of drinking water for sterilization is strong carcinogenic, there is a high possibility in persons health hazard. The titanium dioxide was reduced at 900-degree Centigrade by the gas atmosphere (CO or H2). It was found that the concentration of the bromic acid ion in water was decreased at time when the reduced titanium oxide was added to water including the bromic acid ion. The bromic acid ion in water could be adsorbed by the titanium oxide reduced. In addition, it was suggested that the bromic acid ion could be decomposed into the bromide ion with low carcinogenic by using the photocatalitic function of titanium oxide under UV irradiation.
Authors: N. Miyajima, H. Takagi, Y. Yamada, Hiroaki Hatori
Abstract: The effect of surface modification by nanoparticles of metal compounds was investigated by means of gas and vapor adsorption analysis. The surface of activated carbon fiber cloths was modified by loading of Li2CO3 and MgO nanoparticles. The particles on the carbon surface played as initial adsorption site of water molecules, leading to the promotion of micropore filling without diminishing the micropore volume of the porous carbon supports. The increasing characteristic adsorption energy suggested some interaction between methane molecules and the particles.
Authors: Yi Fan Yuan, Jiu Li Wang
Abstract: With the rapid development of hydropower in China, there are a lot of reservoirs under constructions are put into operation. Therefore, resource scheduling of distributed water conservancy project has become a key focus in current researches. Based on distributed water multi-level resources, the paper put forward to apply the improved genetic algorithm to reservoir resource scheduling. In this way, water level sequence can be the basic genetic algorithm coding scheme, and storage status of reservoir can be stored with the array. Then the genetic algorithm coding can be operated based on the corresponding array index of each reservoir. The paper tries to prove the feasibility of this scheduling policy with some examples, simplifying the process of scheduling algorithm and providing guiding basis for water resource scheduling.
Authors: An Ming She, Wu Yao, Wan Cheng Yuan
Abstract: The water distribution in hardened cement paste with different ages, water to cement ratio (w/c) and different cured methods were investigated by low field NMR. The transverse relaxation time, T2, was used as a parameter to describe the water phase constrained in pores. The results show that the T2 distributions of pastes in the early age are bimodal distribution. As the curing time increase, the T2 distribution peaks shift gradually to the short T2 values reflecting the decrease of mean pore dimension as well as the increase of specific surface area resulted from the gel products. In addition, the influences of initial water to cement ratio and cure methods on water distribution are occurred mainly during the early age. When cured to 28 days, the differences of water distribution in various samples are unconspicuous.
Authors: Victor Khasanov, Yuri Slizhov, Alexandra Makarycheva, Anton Chumakov
Abstract: Analysis of organic acids in natural water samples using by the distillation followed by the SPE procedure at Strata-X and GC-MS of trimethylsilane derivatives. Influence of distillation and elution, as well as a cartridge housing material, on the compounds recovery was discussed. Data on organic acids in some natural samples are provided.
Authors: Alexander P. Ilyin, Liudmila O. Root, Andrei V. Mostovshchikov
Abstract: The problems of hydrogen energetic as well as a method of high pure hydrogen obtaining are presented in the paper. It was suggested to use the reaction of aluminium nanopowder with water, as the reaction proceeds with high rate even at ambient conditions (the rate of hydrogen emission reached 18 ml/(s∙g)) and high degree of conversion (up to 100 %). The unreasonableness of the replacement of aluminium nanopowder to coarse-grained powder in this reaction due to the low efficiency is shown in the article. As a solution for pure hydrogen obtaining, a phenomenon of self-heating of aluminum nanoparticles and the resulting hydrogen, as well as the effect of its high-temperature diffusion through the membrane of ultrahigh molecular weight polyethylene were used.
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