This study evaluates the potential of various coagulants to enhance the efficiency of total phosphorus removal facilities in a sewage treatment plant. After analyzing the existing water quality conditions of the sewage treatment plant, the coagulant of poly aluminium chloride was experimentally applied to measure its effectiveness. In this process, the use of poly aluminium chloride and polymers in various ratios was explored to identify the optimal combination of coagulants. The experimental results showed that the a coagulants combination demonstrated higher treatment efficiency compared to exclusive use of large amounts of poly aluminium chloride methods. Particularly, the appropriate combination of poly aluminium chloride and polymers played a significant role. The optimal coagulant combination derived from the experiments was applied in a micro flotation method of real sewage treatment plant to evaluate its effectiveness. This study presents a new methodology that can contribute to enhancing the efficiency of sewage treatment processes and reducing environmental pollution. This research is expected to make an important contribution to improving to phosphorus remove efficiency of similar wastewater treatment plant and reducing the ecological impact from using coagulants in the future.

In this paper, the cause of mortar baseplate breakage was analyzed by diving into cross-section, material, process, and design aspects. As a result of observing the fracture surface and non-fracture suface using optical equipment, it was possible to confirm changes in the shape of disconnected line and metal surface at a specific area. In addition, a number of linear defects due to overlap were found. Flow analysis was performed using the Deform program to verify changes during the production process. According to the result, a drop test was performed on each of the lap detection baseplate, undetection baseplate, and removed product to verify the presumptive cause of the rupture of the poplite.

There are two primary sludge drying methods such as the direct heating microwave method and the indirect heating steam one. In this study, the drying treatment facility at sewage treatment plant A applied both of these drying methods. The research aimed to investigate the optimal operation approach for the drying facility, considering the input sludge and the moisture content data after the drying process. Moisture content and removal rate data were executed at the research facility from January 2016 to December 2018. First, the microwave, a direct heating drying method, performed intensive drying only on the outer surface of the sludge by directly applying heat to the sludge using far infrared rays, so effective sludge drying was not achieved. On the other hand, the steam method of the indirect heating method used steam from a gas boiler to maximize the utilization of the heat transfer area and reduce energy of the dryer, resulting in an effective sludge drying efficiency. The sludge moisture content brought into the sludge drying facility was about 80%, but the moisture content of the sludge that went through the drying facility was less than 10% of the design standard. Therefore, the steam method of the indirect heating method is more effective than the microwave method of the previous direct heating method and is more effective for maintenance It has proven that it is an efficient method of operating construction facilities.

본 연구는, 지방재정 365의 2021년 예산지출 자료를 바탕으로 지방자 치단체의 청년 대상 고용사업을 추출하여 OECD 통합사회지출(SOCX)의 적극적 노동시장 정책(Active Labor Market Policy) 분류에 따라 재분 류, 분석하였다. 또한, 연구결과를 바탕으로 연세대학교 생명윤리위원회 (IRB)의 승인을 받아 지방자치단체의 청년 정책 담당 공무원과 전문가의 인터뷰를 진행하여 지방자치단체 청년고용정책의 현황에 대해 추가로 분 석하였다. 데이터 분석결과 정책 사업 수 측면에서는 창업 지원사업이 가장 많았으며, 예산 지출액 기준으로는 고용 보조사업의 비율이 가장 높았다. 인터뷰를 통하여 지방자치단체의 청년고용정책의 실제 집행 현 황을 살펴본 결과 고용 보조사업은 당사자 집단의 참여를 통해 질적으로 나아지고 있다는 것을 확인할 수 있었다. 또한, 창업지원 사업의 경우 경 제적, 사회적 기반이 취약한 청년층이 필요로 하는 실질적인 지원 즉 사 무공간 제공, 주거공간 제공, 창업 인큐베이팅 교육 지원 등에 대한 청년 층의 만족도가 높다는 것이 확인되었다.

To fabricate intermetallic nanoparticles with high oxygen reduction reaction activity, a high-temperature heat treatment of 700 to 1,000 °C is required. This heat treatment provides energy sufficient to induce an atomic rearrangement inside the alloy nanoparticles, increasing the mobility of particles, making them structurally unstable and causing a sintering phenomenon where they agglomerate together naturally. These problems cannot be avoided using a typical heat treatment process that only controls the gas atmosphere and temperature. In this study, as a strategy to overcome the limitations of the existing heat treatment process for the fabrication of intermetallic nanoparticles, we propose an interesting approach, to design a catalyst material structure for heat treatment rather than the process itself. In particular, we introduce a technology that first creates an intermetallic compound structure through a primary high-temperature heat treatment using random alloy particles coated with a carbon shell, and then establishes catalytic active sites by etching the carbon shell using a secondary heat treatment process. By using a carbon shell as a template, nanoparticles with an intermetallic structure can be kept very small while effectively controlling the catalytically active area, thereby creating an optimal alloy catalyst structure for fuel cells.

The purpose of this study is to experimentally analyze the seismic performance of beam-column specimens with vertical irregular, which were reinforced with RHS (Replaceable steel haunch system). a steel haunch system. To evaluate the seismic performance of the RHS, three specimens were manufactured and subjected to cycle loading tests. Retrofitted specimens have different beam-upper column stiffness ratio as a variable. The stiffness ratio of beam-upper column were considered to be 1.2 and 0.84. As a result of the test, the specimen reinforced with RHS showed improved maximum load and effective stiffness, and energy dissipation capacity compared to the non-retrofitted specimen with same beam-upper column stiffness ratio. The specimen with 0.84 beam-upper column stiffness ratio showed improved performance than the specimen with 12.

Wastewater management is increasingly emphasizing economic and environmental sustainability. Traditional methods in sewage treatment plants have significant implications for the environment and the economy due to power and chemical consumption, and sludge generation. To address these challenges, a study was conducted to develop the Intermittent Cycle Extended Aeration System (ICEAS). This approach was implemented as the primary technique in a full-scale wastewater treatment facility, utilizing key operational factors within the standard Sequencing Batch Reactor (SBR) process. The optimal operational approach, identified in this study, was put into practice at the research facility from January 2020 to December 2022. By implementing management strategies within the biological reactor, it was shown that maintaining and reducing chemical quantities, sludge generation, power consumption, and related costs could yield economic benefits. Moreover, adapting operations to influent characteristics and seasonal conditions allowed for efficient blower operation, reducing unnecessary electricity consumption and ensuring proper dissolved oxygen levels. Despite annual increases in influent flow rate and concentration, this study demonstrated the ability to maintain and reduce sludge production, electricity consumption, and chemical usage. Additionally, systematic responses to emergencies and abnormal situations significantly contributed to economic, technical, and environmental benefits.

Korea's facility horticultural heating costs account for a high proportion. Therefore, it is the most important factor to consider in greenhouse construction. It is important to assess the heating load of greenhouses. But there is not much data from the weather station. This study determined the heating load for each segmented area using the spatial correction method. The heating degeneration calculated from standard weather data (AHDH and BHDH) and total weather data (CHDH and DHDH) is consistent. However, there was a big difference between AHDH and DHDH. Therefore, the updated heating load data for each region is needed. Each of the four types of set temperatures (8℃, 12℃, 16℃, 20℃) was provided, and the heating temperature setpoint (℃) for each region of 168 cities and counties was presented. As a result of the analysis, the reliability of about 99% was confirmed in most of the regions suggested in this study. By using the calculated heating load for each region, it is possible to predict and utilize energy consumption and management costs.

This study aims to assess the seismic performance of retrofitted reinforced concrete columns using a Replaceable Steel Brace (RSB) system, subjected to combined axial, lateral, and torsional loadings. Through experimental testing, one non-retrofitted concrete column specimen and two retrofitted specimens with variable sliding slot lengths were subjected to eccentric lateral loads to simulate realistic seismic loading. The retrofitted specimens with RSBs exhibited enhanced resistance against shear cracking, effective torsional resistance, and demonstrated the feasibility of easy replacement. The RSB system substantially improved seismic performance, achieving approximately 1.7 times higher load capacity and 3.5 times greater energy dissipation compared to non-retrofitted column, thus validating its efficacy under combined loading conditions.

The purpose of this study is to experimentally analyze the seismic performance of column with RSB (Replaceable Steel Brace), a steel brace system with slot length as a variable. To evaluate the seismic performance of the RSB, three specimens were manufactured and subjected to cyclic loading tests. The length of the sliding slots were considered to be 5 mm and 10mm to enable the brace to resist the load from the initiation of flexural crack and shear crack. As a result of the test, the specimen reinforced with the RSB showed improved maximun load and effective stiffness, and energy dissipation capacity compared to the non-reinforced specimens. The specimens with 5mm sliding slot showed little difference in test result compared to the specimen with a 10mm sliding slot, indicating that the length of sliding slot has little influence on the effectiveness of RSB.

This paper is a study on the malfunction that occurred during the power supply logic of the Gunner Display Device during Mortar Functional Firing under low temperature conditions. As a result of the phenomenon reproduction test and its analysis, the cause of the malfunction of the Gunner Display Device was Glitch, which occurred in the process of converting the image signal, and the improved software was applied to the Gunner's Display System by ignoring some of the image signal conversion process that causes Glitch. The improved Gunner Display Device passed the validity test and applied the improvement to the mortars. As a result of this study, several suggestions for power supply and control logic were proposed. It is expected that this study will be used as a reference in the future design of similar weapons systems.

Seismic fragility curves play a crucial role in assessing potential seismic losses and predicting structural damage caused by earthquakes. This study compares non-sampling-based methods of seismic fragility curve derivation, particularly the probabilistic seismic demand model (PSDM) and finite element reliability analysis (FERA), both of which require employing sophisticated finite element analysis to evaluate and predict structural damage caused by earthquakes. In this study, a three-dimensional finite element model of API 5L X65, a buried gas pipeline widely used in Korea, is constructed to derive seismic fragility curves. Its seismic vulnerability is assessed using nonlinear time-history analysis. PSDM and a FERA are employed to derive seismic fragility curves for comparison purposes, and the results are verified through a comparison with those from the Monte Carlo Simulation (MCS). It is observed that the fragility curves obtained from PSDM are relatively conservative, which is attributed to the assumption introduced to consider the uncertainty factors. In addition, this study provides a comprehensive comparison of seismic fragility curve derivation methods based on sophisticated finite element analysis, which may contribute to developing more accurate and efficient seismic fragility analysis.

This study aimed to provide fundamental data that could guide high school students' night eating behavior by investigating habits of their night eating consumption during COVID-19 pandemic (From 2021/5/13 to 5/20). Association between their eating habits and the Nutrition Quotient for Korean Adolescents (NQ-A) were also explored. This study included a total of 604 students, among whom 441 students were identified as night eating consumers. Among all subjects, 30.5% consumed night eating 3~4 times a week, 27.3% consumed 1-2 times a week, and 27.0% did not consume any night eating at all. The high-night eating group had a higher score of total NQ-A than the non-night eating group for both male (p<0.05) and female (p<0.001) students. This was because male students in the high-night eating group reported significantly higher rates of daily dinner consumption compared to non-night eating group. Furthermore, both male (p<0.05) and female (p<0.001) students showed a significant increase in ‘Moderation’. ‘Diversity’ was also significantly increased in female studies (p<0.05) as subcategories of dietary habits according to night eating frequency. These findings highlight the need for practical research to develop nutritional guidelines for night eating that reflect preferences of students while providing adequate nutritional habits.

This study aims to evaluate the anti-inflammatory effect of Auricularia auricula-judae ethanol extract (AEE) in LPS-induced RAW264.7 cells and dextran sulfate sodium (DSS)-induced acute colitis mice. The highest levels of total polyphenols and DPPH radical scavenging activity were observed in AEE. Also, NO production was reduced in a dose-dependent manner in RAW264.7 cells stimulated by lipopolysaccharide (LPS). AEE was suspended in distilled water and administration per oral at different doses of 100 and 300 mg/kg body weight every day with 3% DSS in drinking water for 7 days. The sample AEE 100 and 300 mg/kg significantly increased body weight, colon length and decreased disease activity index (DAI) score. Histological features showed that 100 and 300 mg/kg of AEE suppressed edema, mucosal damage and the loss of crypts induced by DSS. The serum levels of TNF- and IL-6 were measured in acute colitis mice using ELISA kits. Levels of TNF- and IL-6 in serum were significantly decreased by topical application of AEE. Therefore, AEE increases antioxidant and anti-inflammatory activity, and it is thought that it can effectively help prevent colitis.

수소는 다양한 신재생에너지 중 환경친화적인 에너지로 각광받고 있지만 농업에 적용된 사례는 드물다. 본 연구는 수소 연료전지 삼중 열병합 시스템을 온실에 적용하여 에너지를 절 약하고 온실가스를 줄이고자 한다. 이 시스템은 배출된 열을 회수하면서 수소로부터 난방, 냉각 및 전기를 생산할 수 있다. 수소 연료 전지 삼중 열 병합 시스템을 온실에 적용하기 위해 서는 온실의 냉난방 부하 분석이 필요하다. 이를 위해서는 온 실의 형태, 냉난방 시스템, 작물 등을 고려해야 한다. 따라서 본 연구에서는 건물 에너지 시뮬레이션(BES)을 활용하여 냉 난방 부하를 추정하고자 한다. 전주지역의 토마토를 재배하 는 반밀폐형 온실을 대상으로 2012년부터 2021년까지의 기 상데이터를 수집하여 분석했다. 온실 설계도를 참고하여 피 복재와 골조를 모델화하여 작물 에너지와 토양 에너지 교환을 실시했다. 건물 에너지 시뮬레이션의 유효성을 검증하기 위 해 작물의 유무에 의한 분석, 정적 에너지 및 동적 에너지 분석 을 실시했다. 또한 월별 최대 냉난방 부하 분석에 의해 평균 최 대 난방 용량 449,578kJ·h-1, 냉방 용량 431,187kJ·h-1이 산정 되었다.

2020년 6월부터 8월까지 일본 도쿄 남쪽 940 km 해상에 위치한 니시노시마 화산이 분화하였다. 2020년 7월 말 발생한 분화로 인한 화산재와 화산가스 일부가 우리나라에 영향을 주었을 가능성이 있는 것으로 보도되었다. 본 연구에 서는 화산재 확산 수치모의 프로그램인 Ash3D를 이용하여 현지시각 2 02 0년 7월 2 8일 0시에 화산폭발지수 3의 분화가 발생한 것으로 설정하고 수치모의를 실시하였다. 수치모의 결과, 화산재가 니시노시마 인근에서 동풍을 타고 7월 30일 새벽 오키나와에 도달한 이후 남풍을 타고 북상하여 8월 1일 제주도에 상륙하고 시계방향으로 회전하듯이 이동하면서 8월 2일에는 남부지방에 영향을 주는 것으로 나타났다. 실제 측정된 PM10 미세먼지농도는 제주도 고산기상관측소에서 8월 1일부터, 부산 구덕산기상관측소에서는 8월 2일부터 상승한 것으로 나타나 니시노시마 화산 분화가 제주도 및 남 부지방의 미세먼지 수치에 영향을 준 것으로 보인다.

본 연구에서는 국내에서 유통되는 식·약공용농산물의 잔 류농약 실태를 조사하기 위해 7품목 72건 대상으로 잔류 농약을 분석했다. 시료는 QuEChERS법으로 전처리한 후 GC-MS/MS, LC-MS/MS를 이용하여 분석했다. 식·약공용 농산물 총 7품목 72건 중 42건(58.3%)에서 잔류농약이 검 출되었으며, 검출된 농산물은 복분자 1건, 구기자 14건, 대 추 9건, 오미자 10건, 모과 1건, 생강 5건, 영지버섯 2건 이었다. 그 중 구기자 2건(11.8%), 오미자 1건(7.1%), 영 지버섯 2건(100%)에서 잔류농약 허용기준을 초과하여 검 출되었다. 검출농약은 43종으로 살균제 20종 75회, 살충제 23종 58회이었으며, 살균제 carbendazim 및 tebuconazole이 각각 11회로 가장 빈번하게 검출되었다. 허용기준을 초과 하여 검출된 농약은 acetamiprid, cadusafos, chlorpyrifos, flubendiamide, fluopyram, triazophos으로 모두 잔류농약허 용기준이 설정되지 않은 PLS 항목이었다. 결론적으로 잔 류농약 검사 건수, 검출률, 검출빈도를 종합적으로 고려해 볼 때 식·약공용농산물에 대한 지속적인 잔류농약 관리가 필요한 것으로 생각된다.