A Study of the Principles of Missional Pastoral Leadership for South Korean Churches

Since 2000, the Korean Church has increasingly lost public confidence. The reason for this is that pastors have focused on church growth. They have entirely missed the essence of missional ecclesiology. However, the church is generated from the mission of the triune God to redeem all creation. The church should not be identified as a building or a place but as the people of God who are to be sent into the world to participate in the mission of God. The purpose of this thesis project is to present the principles of missional pastoral leadership for an existing Korean church by examining the essentials of missional ecclesiology and the characteristics of the appropriate missional pastoral leadership for the missional church. Literary research and surveys on the attitudes about missional ecclesiology were used; the survey was presented to 50 Korean pastors of various age groups and levels of ministry experience

Inhibition of Chromium(III) Oxidation through Manganese(IV) Oxide Passivation and Iron(II) Abiotic Reduction

Manganese (Mn) oxides are strong oxidants that are ubiquitous in soils and can oxidize redox-active metals, including chromium (Cr). In soil environments, trivalent chromium (Cr(III)) is a benign, immobile micronutrient, whereas the hexavalent Cr(VI) form is present as a highly mobile, toxic chromate oxyanion. Although many studies have characterized the capacity of Mn(III/IV) oxides to oxidize Cr(III) to toxic Cr(VI), the oxidative capacity of Mn oxides in the presence of potentially passivating soil constituents, specifically reduced soluble iron (Fe(II)aq), remains unresolved. We hypothesized that chemical processes at redox interfaces, such as diffusion-limited environments within soil aggregates, can lead to decreased Cr(VI) production from Mn oxide-driven oxidation due to passivation by Fe(II)aq. A multichamber diffusion-limited reactor was used to simulate transport at soil redox interfaces and investigate the capacity of poorly crystalline and crystalline Mn oxides to oxidize solid Cr(III) minerals to Cr(VI) in the presence of Fe(II)aq. As predicted, Cr(VI) was produced through the Mn oxide-catalyzed oxidation of Cr(III) at a rate controlled by the solubility of Cr(OH)3. However, in the presence of Fe(II)aq, the concentration of aqueous Cr(VI) decreased as a function of the Fe(II)aq concentration, where high concentrations of Fe(II)aq completely inhibited Cr(VI) production, likely through both the passivation of the Mn oxide and the direct reduction of Cr(VI) by Fe(II). At both low (14 μM) and high (100 μM) Fe(II)aq concentrations, the iron oxide minerals hematite (Fe2O3) and goethite (α-FeOOH) were associated with the Mn oxides, which can cause surface passivation, a likely role that decreases Cr(III) oxidation. Additionally, the Cr(III) oxidation rate decreased with increasing crystallinity of the Mn oxides whether or not Fe(II) was present

Experimental and Numerical Investigation of Deformable Concrete Median Barrier

In South Korea, the number of vehicles is gradually increasing. The number of heavy vehicles in 2010 increased up to 19% in less than five years. Therefore, the chances of heavy vehicle-concrete median barrier (CMB) collision also became higher than in the past; therefore, a need to study a stricter design level for improving the current CMB (CMB-15) under harsher environments arose. Accordingly, in the present study, a new concrete median barrier was designed under a stricter impact severity, SB6(420 kJ), compared to the current design impact severity, SB5-B (270 kJ). In particular, shock absorbing devices to absorb impact energy were applied to the CMB. An empty space allows the dowel bars to deform and absorb collision energy. Therefore, deformable CMB was designed and tested. The key parameters selected in our study were dowel bar and wire-mesh. A series of numerical analyses were conducted to evaluate the proposed new deformable CMB designs with shock absorbers. Finally, the optimal design, CMB-17S, was proposed after several evaluations of the proposed designs and a full-scale field test. It was found that, although the developed model did not accurately predict the impact sequence due to certain differences between the actual truck and the truck model, the permanent deformation after collision could be well predicted. Based on the observations from a full-scale impact test, it was recommended that the top part of the CMB should be strengthened since major volume loss occurred due to local impact, which appeared to be due to punching shear failure

Numerical and Experimental Analysis to Develop a SB6/H3 High Containment Level Concrete Median Barrier

Abstract As the number of heavy vehicles on the road continues to increase, collisions involving heavy vehicles and concrete median barriers (CMB) occur more frequently than in the past. Consequently, there is a growing need for research into more stringent design standards and improvements to the current CMB and their performance under harsh conditions. High-performance CMB is required to in order to withstand such conditions. This paper presents the results of numerical simulations and full-scale field tests to develop a high-performance CMB. To facilitate the development of the high-performance CMB, the concept of a deformable CMB was applied to the rigid CMB. A new apparatus called the shock absorber composed of dowel bars surrounded by empty space were introduced to make the rigid CMB deformable. In order to prevent local failure at the top of the barrier from a sudden high increase in impact energy, the deformable CMB was strengthened by adding reinforcements and widening the top based on the results of numerical simulations. The full-scale field tests were conducted on the proposed deformable CMB and took into account three appraisal areas: (1) structural adequacy, (2) occupant risk, and (3) vehicle trajectory after collision. The results of these tests showed that the deformable CMB contained and redirected the vehicle without allowing it to penetrate or override the deformable CMB. No detached elements, fragmentation, or other debris from the barrier were present. Therefore, the proposed high-performance CMB fulfilled all of the requirements of the crash test guideline