The Experts below are selected from a list of 12 Experts worldwide ranked by ideXlab platform
Abdelhafid Khelidj - One of the best experts on this subject based on the ideXlab platform.
-
assessment of Liquid Water and gas permeabilities of partially Saturated ordinary concrete
Construction and Building Materials, 2014Co-Authors: Z A Kameche, Fouad Ghomari, Marta Choinska, Abdelhafid KhelidjAbstract:Abstract The durability of concrete depends on its ability to prevent the ingress of aggressive chemical species. Transport properties of concrete, mainly permeability, play a key role in assessing and predicting the durability of reinforced concrete structures. The hydric state affects the transport parameters like permeability which has a large influence on the penetration of aggressive agents and so on durability of concrete. This paper presents an experimental study on relative gas and Water permeabilities of ordinary concrete versus its saturation degree. The experimental results give the measurements of Liquid Water and gas permeabilities of concrete samples with different sizes as well as those of the degree of Saturated Liquid Water obtained by mass weighing. The analysis shows the influence of the saturation degree of concrete on the variation of Water and gas permeabilities. Validation of Van Genuchten–Mualem law for porous media has been verified for ordinary concrete (OC). Moreover, this study highlights the effect of drying temperatures on the intrinsic gas permeability of concrete.
Hideo Narita - One of the best experts on this subject based on the ideXlab platform.
-
methane hydrate crystal growth in a porous medium filled with methane Saturated Liquid Water
Philosophical Magazine, 2007Co-Authors: Daisuke Katsuki, Ryo Ohmura, Takao Ebinuma, Hideo NaritaAbstract:The nucleation, growth and ageing of methane hydrate crystals were observed visually in a porous medium filled with Liquid Water preSaturated with methane. The pore space dimensions of the porous medium were 1.0 × 102 µm. The pressure−temperature conditions at which hydrate formation was initiated corresponded to system subcoolings of 3.4 K, 6.7 K, 12.3 K and 14.1 K, respectively, where the system subcooling denotes the difference of the system temperature from the triple methane−hydrate−Water equilibrium temperature under a given pressure. Faceted (skeletal) hydrate crystals grew and bridged the pore spaces without intervention of a Liquid Water layer when the subcoolings were equal or smaller than 6.7 K. The faceted crystals may form a physical bonding with the walls of the porous medium. At the higher subcoolings, the dispersive formation of dendritic crystals and subsequent morphological change into particulate crystals were observed. The bridging of the dendritic crystals is unlikely in the absence o...
Kangchol Mun - One of the best experts on this subject based on the ideXlab platform.
-
use of the international association for the properties of Water and steam iapws formulations iapws 95 iapws if97 making of mollier diagram and t s diagram of Water and steam
Thermal science and engineering, 2020Co-Authors: Cholmin Kim, Hun Kim, Kangchol MunAbstract:Abstract It is very important to correctly calculate the thermodynamic properties of Water and steam needed for design and operation of the main equipment of the power industry such as boilers and steam turbines. On the other hand, the Mollier diagram and T-s diagram of Water and steam are widely used to study or review thermodynamic cycles as well as expansion processes of steam turbines and steam power equipment in the power industry. Presented in this paper are the method and procedures to exactly construct the diagrams. The diagrams involve several lines, including the saturation line, and constant pressure, temperature and vapor fraction lines. In the paper, a method is proposed for correctly calculating other thermodynamic properties of Saturated Liquid Water and Water vapor in saturation line of near-critical region by using the basic equation of region 3 of IAPWS-IF97 and iteration. Then, the procedures to plot the lines are presented by combining the method with IAPWS-95 and IAPWS-IF97, and the Mollier diagram and T-s diagram made in MS-Excel are shown. The method and procedures in the paper can be used not only in making the Mollier diagram, T-s diagram and steam tables, but also in accurately calculating the thermodynamic properties of Saturated Liquid Water and Water vapor.
Z A Kameche - One of the best experts on this subject based on the ideXlab platform.
-
assessment of Liquid Water and gas permeabilities of partially Saturated ordinary concrete
Construction and Building Materials, 2014Co-Authors: Z A Kameche, Fouad Ghomari, Marta Choinska, Abdelhafid KhelidjAbstract:Abstract The durability of concrete depends on its ability to prevent the ingress of aggressive chemical species. Transport properties of concrete, mainly permeability, play a key role in assessing and predicting the durability of reinforced concrete structures. The hydric state affects the transport parameters like permeability which has a large influence on the penetration of aggressive agents and so on durability of concrete. This paper presents an experimental study on relative gas and Water permeabilities of ordinary concrete versus its saturation degree. The experimental results give the measurements of Liquid Water and gas permeabilities of concrete samples with different sizes as well as those of the degree of Saturated Liquid Water obtained by mass weighing. The analysis shows the influence of the saturation degree of concrete on the variation of Water and gas permeabilities. Validation of Van Genuchten–Mualem law for porous media has been verified for ordinary concrete (OC). Moreover, this study highlights the effect of drying temperatures on the intrinsic gas permeability of concrete.
Daisuke Katsuki - One of the best experts on this subject based on the ideXlab platform.
-
methane hydrate crystal growth in a porous medium filled with methane Saturated Liquid Water
Philosophical Magazine, 2007Co-Authors: Daisuke Katsuki, Ryo Ohmura, Takao Ebinuma, Hideo NaritaAbstract:The nucleation, growth and ageing of methane hydrate crystals were observed visually in a porous medium filled with Liquid Water preSaturated with methane. The pore space dimensions of the porous medium were 1.0 × 102 µm. The pressure−temperature conditions at which hydrate formation was initiated corresponded to system subcoolings of 3.4 K, 6.7 K, 12.3 K and 14.1 K, respectively, where the system subcooling denotes the difference of the system temperature from the triple methane−hydrate−Water equilibrium temperature under a given pressure. Faceted (skeletal) hydrate crystals grew and bridged the pore spaces without intervention of a Liquid Water layer when the subcoolings were equal or smaller than 6.7 K. The faceted crystals may form a physical bonding with the walls of the porous medium. At the higher subcoolings, the dispersive formation of dendritic crystals and subsequent morphological change into particulate crystals were observed. The bridging of the dendritic crystals is unlikely in the absence o...
