Mechanism of delayed leaching of heavy metals from naturally contaminated soils

Naturally contaminated soils that contain contaminants deep within the particles may show delayed leaching. To incorporate this, a novel approach for predicting the distribution of contaminants, both in the soil particle and surrounding liquid, is achieved using the finite difference method. The approach is named the 'intraparticle pore-diffusion model' and is applied to simulate the batch leaching test of heavy metal contaminated soils. Intraparticle diffusion and sorption equilibrium are considered. The desorption phenomena of heavy metal from soil particles are considered as a one-dimensional, polar-symmetric problem in the spherical coordinate system by supposing soil particles to be porous, perfect spheres. The results indicate that soil constituted of larger particles leach more contaminants at a certain time and faster for a certain leaching amount

The effect of particle shape on rockfall events

The effects of rock shape and initial orientation on the rockfall phenomena are studied using a two-dimensional polygonal discrete element method (DEM). In the simulation, rock particles with the same mass but different shapes are dropped from the same height onto a straight slope to investigate the variations in both translational and rotational kinetic energies and the runout distance. Parametric studies under varied angularity and aspect ratio of the rock revealed a significant effect of rock shape and initial orientation on the runout distance

Comparison of Lattice Boltzmann Method and Finite Volume Method with Large Eddy Simulation in Isothermal Room Flow

Lattice Boltzmann method (LBM), as a new computational fluid simulation method, has aroused widespread attention in recent decades within engineering practice. LBM with large eddy simulation (LBM-LES) model is commonly used in predicting high Reynolds flow, and is considered to have a prediction accuracy similar to traditional finite volume method (FVMLES). Nonetheless, a systematic discussion on the accuracy of LBM-LES, and its consistency with FVM-LES, in indoor turbulent flow situations, is still insufficient. In this study, simulations of an indoor isothermal forced convection benchmark case (from IEA Annex 20) are implemented by using both LBM-LES and FVM-LES, with the aim of comparing the accuracies of LBM-LES and FVM-LES, in indoor turbulent flow situations. A comparison of their relative computation speeds, and parallel computation performances, is also implemented. The results show that LBM-LES can achieve the same level of accuracy as FVM-LES, in indoor turbulent flow situations; however, more refined meshes are required. Compared with FVMLES, half size grids are required for LBM-LES to approach similar levels of accuracy, meaning that the meshes of LBM-LES are approximately eight times as large as FVM-LES. The computation speeds of both LBM-LES and FVM-LES scale well, with the increase in the number of computation cores in one node. Their computation speeds (with the same accuracy) approach a similar level; however, the parallel computation speed of the LBM-LES speed can be larger than FVM, owing to its superior parallel speedup performance

The current situation and prospects for Japanese language education in secondary schools in Croatia: Based on a questionnaire survey

国際交流基金の報告によると、現在クロアチアの中等教育機関では日本語 教育は行われていないということがわかった。なぜクロアチアの中等教育機 関において、日本語教育は行われていないのか。クロアチアの中等教育機関 で日本語教育を行うには、どのような指導が適切か。実際に、地元の高校生 にアンケート調査を行った。すると、アンケートに答えた学生のほとんどが、 日本文化や日本語に対し接触経験を持つと答え、半数以上の生徒が高校で 日本語を勉強したいと回答していた。また、ニーズ調査では、多くの学生が、 趣味上の理由で日本語を習い始めたかったという点から、クロアチアの中等 教育機関で日本語教育を開始する場合、文法積み上げ式の教科書ではな く、Can-do式の教科書を使って学習を行った方がいいと考える。Trenutno, prema izvješću Japanske fondacije, obrazovanje japanskoga jezika se ne provodi u srednjoškolskom obrazovanju u Hrvatskoj, dok je podučavanje japanskoga jezika široko rasprostranjeno u srednjim školama nekih drugih susjednih država. U ovome radu opisujemo anketu provedenu među učenicima srednjih škola u Hrvatskoj s ciljem upoznavanja potreba, interesa, motivacije, stavova učenika u vezi s japanskim jezikom i kulturom te diskutiramo o rezultatima ankete i mogućim pristupima učenju i podučavanju japanskoga jezika u srednjim školama u Hrvatskoj u budućnosti. Anketa je provedena s lokalnim srednjoškolcima u okviru projekta „Posjete srednjim školama u Hrvatskoj“ koji je osmišljen na Odsjeku za azijske studije Filozofskog fakulteta Sveučilišta Jurja Dobrile u Puli i podržan od strane Japanske fondacije. Većina je učenika rekla da imaju iskustva s japanskim jezikom i kulturom, ponajprije u doticaju s japanskim animiranim crtanima, filmovima, japanskim stripovima i igricama, a više od polovice učenika izjavilo je da bi htjeli učiti japanski u srednjoj školi. Također, rezultati istraživanja potreba učenika ukazuju na to da bi se za podučavanje japanskoga jezika u srednjoškolskim institucijama u Hrvatskoj trebalo koristiti udžbenikom koji sadrži „mogu da“ formulacije (can-do statements) a ne udžbenik zasnovan na gramatici, s obzirom na to da mnogi učenici žele učiti japanski jezik iz hobija, npr. jer žele posjetiti Japan i pričati s Japancima, a ne nužno za potrebe budućega zanimanja.Currently, according to a report from the Japan Foundation, Japanese language education is not being conducted in secondary education in Croatia, while in some neighbouring countries Japanese language learning is much more widespread in secondary schools. This paper describes a questionnaire survey conducted on local high school students in relation to their needs, interests, motivation and attitudes towards the Japanese language and culture, and discusses the results of the questionnaire as well as possible approaches in the introduction of Japanese language education in Croatian secondary schools in the future. The questionnaire was conducted within the scope of the project “Visiting secondary schools in Croatia” that was launched by Department of Asian Studies at the Faculty of Humanities Juraj Dobrila University of Pula and supported by the Japan foundation in 2018. Most of the students have said that they had experiences with Japanese language and culture, mostly having come into contact with Japanese anime, manga and games, and more than half of the students have indicated they would like to study Japanese in their high schools. Also, the survey of needs indicates that a textbook with a can-do approach should be used when starting Japanese language education at secondary school institutions in Croatia instead of a textbook using the grammar build-up approach. This is due to the fact that many students want to start learning Japanese as a hobby due to an interest in visiting Japan and communicating with Japanese people, and not to use it particularly for their future profession