Search

Many barrier materials are used around industries, construction areas, livestock dump sites, waste landfills, and underground oil storage tanks. In the case of barriers, even if there is no inflow of contaminants, they do not provide selective permeability, develop water barrier properties, and hinder groundwater flow when contaminants encounter groundwater. Recently, contaminated sites that are difficult to resolve with current purification technologies continue to emerge. Pollutants flow into groundwater through the advection and diffusion by leaking. The pollutants introduced in this way cause pollution to the surrounding environment, and various types of severe underground environmental pollution problems occur depending on the type of pollutants leaked. Therefore, using a material that has the property of adsorbing organic contaminants and gelling them is harmless to the environment by penetrating groundwater under normal conditions. It has the property of selectively adsorbing the pollutant and gelling it upon contact with it underground. Therefore, the authors aim to study the applicability of polynorbornene and polyolefin as components of smart barrier materials that make barrier materials impermeable through the adsorption of pollutants, swelling, and coagulation behavior in this study. The components of smart barrier materials include Ottawa sand, organo-bentonite, polynorbornene, and polyolefin. Polynorbornene and polyolefin adsorb only organic pollutants selectively. Before applying polynorbornene and polyolefin to the barrier material, TCLP was performed to evaluate environmental hazards. As a result of heavy metal analysis, it was determined that there was no environmental hazard. The pH results are 7.27 for polynorbornene and 7.31 for polyolefin, indicating that both materials are slightly alkaline. In addition, as a result of testing with TCE (stock solution) and TPH (diesel crude oil) to confirm the swelling effect when in contact with organic pollutants, the efficiency of pollutant adsorption and swelling was found to be high when the ratio of polynorbornene: polyolefin = 6:4. Therefore, when using the material used in this study, it is expected that it can be applied as a component of a smart barrier material that selectively blocks pollutants.

We study the mixed formulation of the abstract Hodge Laplacian on axisymmetric domains with general data through Fourier finite element methods (Fourier-FEMs) in weighted function spaces. Closed Hilbert complexes and commuting projectors are used as in the work of Arnold, Falk & Winther, (2010, Finite element exterior calculus: from Hodge theory to numerical stability. Bull. Amer. Math. Soc. (N.S.) , 47 , 281–354), by using the new family of finite element spaces for general axisymmetric problems introduced in Oh, (2015, de Rham complexes arising from Fourier-FEMs in axisymmetric domains. Comput. Math. Appl. , 70 , 2063–2073). In order to get stability results and error estimates for the discrete mixed formulation, we construct commuting projectors that can be applied to functions with low regularity. [ABSTRACT FROM AUTHOR]

The question of whether bilingualism conveys a broader advantage in executive functions has recently been controversially discussed, with the empirical findings presenting a complex pattern of positive and null results. Here we present results from three standard tasks measuring executive functions (Flanker; Simon; Spatial Stroop) in which we compared performance of English monolingual to Chinese–English bilingual young adults. Participants provided responses via movement of a computer mouse rather than the conventional key presses, which provides a rich signal of the unfolding response dynamics. Clear differences between bi- and monolinguals emerged, with the former providing more 'efficient' responses than the latter. Results are discussed regarding the extent to which these results can be characterised as a genuine "bilingual advantage". [ABSTRACT FROM AUTHOR]

This paper builds a new framework to analyse axisymmetric problems through differential forms and exterior calculus. We construct a new weighted L2 de Rham complex that arises when analysing axi-symmetric problems. By constructing its dual complex, we obtain a Hodge decomposition and a Poincaré inequality in weighted spaces, and the well-posedness of the weighted mixed Hodge Laplacian problem. The stability and convergence of the discrete weighted mixed Hodge Laplacian problem are also achieved by using bounded cochain projections. [ABSTRACT FROM AUTHOR]

In this paper, we will construct and analyze a multigrid algorithm that can be applied to weighted H (div) problems on a two-dimensional domain. These problems arise after performing a dimension reduction to a three-dimensional axisymmetric H (div) problem. We will use recently developed Fourier finite element spaces that can be applied to axisymmetric H (div) problems with general data. We prove that if the axisymmetric domain is convex, then the multigrid V-cycle with modern smoothers will converge uniformly with respect to the meshsize. [ABSTRACT FROM AUTHOR]