The recent earthquake in Korea caused a lot of damage to reinforced concrete (RC) columns with non-seismic details. The nonlinear analysis enables predicting the hysteresis behavior of RC columns under earthquakes, but the analytical model used for the columns must be accurate and practical. This paper studied the nonlinear analysis models built into a commercial structural analysis program for the existing RC columns. The load-displacement relationships, maximum strength, initial stiffness, and energy dissipation predicted by the three analysis models were compared and analyzed. The results were similar to those tested in the order of the fiber, Pivot, and Takeda models, whereas the fiber model took the most time to build. For columns subjected to axial load, the Pivot model could predict the behavior at a similar level to that of the fiber model. Based on the above, it is expected that the Pivot model can be applied most practically for existing RC columns.

As earthquakes have increased in Korea recently, people are paying attention to the seismic performance of buildings built in the past. Many school buildings in Korea were built based on standard drawings before the seismic design was applied. However, since school buildings are often designated as emergency evacuation facilities in case of disasters such as earthquakes, seismic evaluation and retrofit must be done quickly. This study investigated the failure modes among structural components (beams, columns, and joints), focusing on 1980s standard drawings for school buildings. The effects of column axial force, partial masonry infills, and different material strengths for concrete and rebar were considered for detailed evaluation. As a result, most of the joints were found to be the weakest among structural components. Column axial forces tended to make the joints more vulnerable, and partial masonry infills increased the possibility of joint failure and shear failure in columns.

As earthquakes continue to occur in Korea in recent years, seismic evaluation and retrofit of existing school buildings have been carried out. Many domestic school buildings were built using or referring to standard drawings. Therefore, if the overall structural characteristics of a school building can be known first based on standard drawings, it can be provided as valuable data for detailed seismic evaluation. For this reason, this study investigated the weak structural components and failure modes by comparing the strength of beams, columns, and joints constituting standard school buildings constructed in the 1980s. The evaluation was performed for different types of standard drawings and different material strengths. The results showed that the joint was mainly the weakest due to the eccentricity, and the failure modes were partially changed depending on the material strength.

GABA(γ-aminobutric acid)는 비단백질성 아미노산으로 뇌기능 촉진, 신경안정 및 혈압저하 효과 등의 생리 활성 기능물질로 알려져 있다. GABA 고함유 배추김치를 제조하기 김치제조 시 사용되는 부재료로 표고버섯, 느타리, 팽이, 큰느타리, 양송이 등 국내산 버섯류를 수집하여 열수 및 5% trichloroacetic acid 로 추출하고 HPLC을 이용하여 GABA 함량을 분석하였다. 버섯류 중에는 양송이 39.46 mg 100 g-1, 큰느타리 31.63 mg 100 g-1, 느타리 70.75 mg 100 g-1로 순으로 느타리 버섯이 가장 높은 GABA 함량을 나타내어 김치 부재료로 사용하였다. 느타리 버섯이 함유된 김치육수에 GABA 생성 Lactobacillus 유산균을 접종하고 30°C에서 24시 간 발효시킨 육수를 이용하여 김치를 제조한 후, 4°C에서 숙성 기간별 GABA 및 glutamic acid 함량변화를 분석한 결과, 김치는 초기에 비해 19일 후 GABA 함량이 88.59 mg g-1 증가하였고, 김치국물도 173.79 mg 100 mL-1의 증가효과를 보였다. 이상의 결과를 통해 배추김치 제조시 부재료로 느타리 버섯과 실온에서 Lactobacillus 균을 접종하여 발효한 육수를 사용시 배추김치의 GABA함량을 증진시키는 효과를 얻을 수 있었다.

PURPOSES : Visibility of lanes on the road improves as retro-reflectivity rises. This helps reduce traffic accidents at nighttime or in bad weather. This study aimed to evaluate the effects of improved visibility on reduction of traffic accidents when the color of the lane in the median of the highway was changed from yellow to white. METHODS: In order to evaluate the accident reduction effect of the white left shoulder line, Hauer (1997)'s Comparison-Group method was chosen as an analysis methodology. The JungBu-2 highway, which is equipped with the white left shoulder line and is in trial operation, was chosen as a target for analysis. Data of accidents for 10 months before and after installation was collected and analyzed. In addition to the number of accidents, the types of accidents were classified into nighttime accidents, accidents in bad weather, and median collisions. The accident reduction effect of improved visibility of lanes was analyzed. RESULTS : The analysis’finding showed that installation of the white left shoulder line decreased the number of accidents by 28%. Moreover, improvement in visibility was effective in reducing nighttime accidents by 67.63%, accidents in bad weather by 55.19%, and median collisions by 48.55%. CONCLUSIONS: Based on the analysis’results in this study, it was concluded that white left shoulder line on the freeway contributed to reduce traffic accidents, especially nighttime accidents, accidents in bad weather, and median collisions.

본 연구의 목적은 지지체의 친수화가 압력지연삼투(Pressure retarded osmosis, PRO)막의 투과특성에 미치는 영향에 대해서 알아보고자 하였다. 소수성 지지체인 폴리에스테르를 친수성 고분자인 셀룰로오스 용액을 사용하여 친수화도를 조절하였다. 지지체의 친수화 특성만을 파악하기 위해서 지지층 없이 동일한 활성층을 사용하여 PRO 막 투과 특성을 비교하였다. 사용된 활성층은 1,4-dioxane과 cellulose tri-acetate (CTA, 13 wt%)를 사용하여 제조하였으며, 5 kgf/cm2 압력 하에서 행한 PRO 성능 평가의 경우 투과도가 친수화된 지지체를 사용한 경우와 친수화되지 않은 경우에 각각 1.2 L/m2hr와 0.8 L/m2hr로 친수화된 지지체를 사용할 경우 약 50% 투과량이 증가되는 특성을 보였다. 그러나 셀룰로오스 농도 변화에 따른 지지체의 친수화도 증가가 투과량 변화를 가져오지는 않았다. 이는 지지체를 친수화하기 위해 사용된 셀룰로오스의 농도가 증가함에 따라 지지체의 기공이 막히는 현상에 기인한 것으로 보인다. 이러한 결과를 통해 정삼투공정에서 투과유량을 높이기 위해서는 지지체로서 친수성 소재를 사용하여 분리막을 제조함과 동시에 지지체 기공을 유지하는 것이 중요함을 확인하였다.