In this study, a numerical approach based on mid-point integrated finite elements and a viscous boundary is proposed for time-domain wave-propagation analyses in infinite poroelastic media. The proposed approach is accurate, efficient, and easy to implement in time-domain analyses. In the approach, an infinite domain is truncated at some distance. The truncated domain is represented by mid-point integrated finite elements with real element-lengths and a viscous boundary is attached to the end of the domain. Given that the dynamic behaviors of the proposed model can be expressed in terms of mass, damping, and stiffness matrices only, it can be implemented easily in the displacement-based finite-element formulation. No convolutional operations are required for time-domain calculations because the coefficient matrices are constant. The proposed numerical approach is applied to typical wave-propagation and soil-structure interaction problems. The model is verified to produce accurate and stable results. It is demonstrated that the numerical approach can be applied successfully to nonlinear soil-structure interaction problems.

The efficacy of the natural amendments in improving physical condition as well as waterretention characteristics of the growing media in pot culture was studied on seven different mixratio of growing media applied to soil. Growing media was prepared from peat, perlite, pruningwaste, pulp(3:1:3:3(w/w/w/w)). Growth substrates were prepared by mixing growing media at therates of 0%, 10%, 20%, 30%, 40%, 50% and 100% with soil at 100%, 90%, 80%, 70%, 60%,50% and 0%, respectively. The bulk density tended to decreased with increasing growing mediaproportions. The particle density was lowest(0.6 g/cm3) in sole growing media treatment and theporosity of all the soil mixed growing media(63.2~83.3%) was significantly higher than that ofthe soil as sole medium(60.7%). The water content was lowest in sole soil treatment(5.1%) andgrowing media as sole medium(57.8%) was the closely ideal range for pot culture(>60%). Although substrates were varying water to the atmosphere at similar rates which retained waterfor longer, growing media as sole still remain constant on high water content. It was confirmedthat strongly correlated between bulk density and water retentivity(correlation-0.85).

This study was aimed to determine effects of soil organic amendment as plant growing media component on restoration of planting ground. The changes of soil physical and chemical properties and germination and growth of kentucky bluegrass (Poa pratensis L.) were investigated. For treatments, soil was excavated at depth of 0-50 cm (referred as S1) and at depth of 50-100 cm (referred as S2). Then the half amount of S1 soil was mixed with the soil organic amendment (coir dust 40% (v/v), bottom ash 25%, leaf mold 25%, vermiculite 5%, carbonized rice hull 5%) at a rate of 6% (v/v) (referred as S1CC) and also the half amount of S2 soil was mixed with the soil organic amendment at a rate of 6% (v/v) (referred as S2CC) on pot in a 16 cm diameter and 14 cm height. The experiment was replicated 3 times with 3 pots per replication in randomized block design, and 100 seeds were planted per pot. In results, there was no significant difference in soil pH among the treatments with a slight decrease in soil hydraulic conductivity. However, in the S1CC treatment, positive increases in soil chemical properties, including electrical conductivity, organic matter, phosphoric acid, total nitrogen, exchangeable cation, and cation exchange capacity. Also, the germination rate, plant height, and number of leaves were higher in the S1CC treatment than those in other treatments. These results suggest that the addition of organic amendment to the soil at depth of 0-50 cm might be proper for restoring planting ground.

자생 상록양치류의 대량번식의 체계확립을 위해 기내배양 식물체의 순화기에 있어 순화기 용토종류와 용토내의 pH, 관비효과를 위해 ammonium nitrate 그리고 차광율을 조사한 결과는 다음과 같다. 자생상록 양치류의 순화기에 이식용토 종류를 달리하여 더부살이고사리 외 4종의 상록자생 양치류의 전엽체를 이식함에 있어 전반적으로 상토+마사+펄라이트(2:1:1) 조합에서 포자체의 형성과 생장이 양호하였다. 자생상록 양치류의 순화용토 내에 적합한 pH는 공시식물 종에 따라 적성 pH의 요구성이 pH 5.5～7.5로 다양하게 보였으며, 순화기에 차광 효과는 30%와 50% 차광에서 무차광구에 비해 포자체 형성과 생장이 증가하였다. 또한 순화기의 관비에 관한 효과는 ammonium nitrate 0.5 g/ℓ 첨가가 순화기에 효과적임을 알 수 있었다.