The objectives of this study were (i) to evaluate the effects of temperature and relative humidity on two electrochemical sensors measuring hydrogen sulfide and ammonia using a laboratory testing system for various sensors, and (ii) to propose a calibration method for those concentrations to collect more reliable monitoring data. The effect of temperature and relative humidity was tested under three different conditions, respectively. The linearities measured data under all different conditions for the relative humidity and temperature were excellent, indicating more than 0.99 of R2 for both odor sensors. Under the condition of zero concentration, baselines (intercepts) at zero increased with increasing relative humidity for both hydrogen sulfide and ammonia sensors. The rate of gas concentration according to ADC variation (slopes) increased with increasing relative humidity about only the hydrogen sulfide sensor. In this study, slope, and intercept are utilized for calibration of hydrogen sulfide and ammonia concentration, and the reliability of the data of hydrogen sulfide and ammonia sensors is further enhanced by the relational expression obtained by this paper.

단감 과수원에서 문제가 되고 있는 노린재의 방제 목적으로 사용되는 페로몬트랩의 유인거리를 확인하고, 페로몬트랩의 효율을 증가시킬 수 있는 끈끈이트랩의 사용효과에 대하여 알아보고자 수행되었다. 노린재에 마커로 표시한 후 방사하여 페로몬트랩과 끈끈이트랩에 재포획된 개체수를 조사하였다. 그 결과, 페로몬트랩에 톱다리개미허리노린재가 60 m까지 유인되는 것을 확인하였으며, 끈끈이트랩의 포획률은 0주차 35%, 1주에서 27%, 2주에서 34%, 3주에서 2.9%, 4주에서 0.6%로, 3주 이후부터 급격히 낮아지는 것을 확인하였다. 페로몬트랩과 끈끈이트랩을 동시에 사용한 경우가 페로몬트랩만 단일로 사용한 경우보다 약 12배 높은 포획률을 보였다.

As the part of efforts to respond to the environmental pollution, the demand for clean energy is increasing. Natural gas is one of the most realistic alternatives, and interest in the storage and transportation containers to utilize the natural gas is growing. The production area of ​​natural gas is limited, and in Korea, it is imported in the form of liquefied natural gas. LNG is a cryogenic state with a vaporization point of -163°C, so the ordinary metal cannot be used due to its brittleness. The international maritime organization (IMO) defines the metals that can handle LNG in the IGC Code, and the research is ongoing. This study was a preliminary study to check the weldability of related metals and confirmed the shape of bead on plate (BOP) during the laser welding for each material. In part I, a study was conducted on the high manganese steel, and in part II, a study was conducted on the materials of STS304L and STS316L among the stainless steel. Based on this study, it can be used as an optimal welding condition for the butt and fillet welding.

The estimation of heat source model is very important for heat transfer analysis with finite element method. Part I of this study used adaptive simulated annealing which is one of the global optimization algorithm for anticipating the parameters of the Goldak model. Although the analysis with 3D model which depicted the real situation produced the correct answer, that took too much time with moving heat source model based on Fortran and Abaqus. This research suggests the procedure which can reduce time with maintaining quality of analysis. The lead time with 2D model is reduced by 90% comparing that of 3D model, the temperature distribution is similar to each other. That is based on the saturation of heat transfer among the direction of heat source movement. Adaptive simulated annealing with 2D model can be used to estimate more proper heat source model and which could enhance to reduce the resources and time for experiments.

In this study, Bacillus sp. SRCM 112835 was isolated from soybean paste (Doenjang, Korean Fermented Soy Paste). Bacillus sp. SRCM 112835 showed biosorption of the Cu (II) in aqueous solution. The strain effectively absorbed 30.2% of the Cu (II) from a 52.3 mg/L within 60 min. The properties of the Bacillus sp. SRCM 112835 were investigated by Fourier transform infrared spectroscopy (FT-IR), point of zero charge (pHpzc), and phylogenetic analysis. The influence of initial pH (2.08-9.98) and biomass dosage (0.005-0.07 g) were likewise probed. Isotherm and kinetic experiment results suggested that the Langmuir isotherm and pseudo-second-order kinetic models well-fitted the experimental data, respectively.

Natural gas is the most realistic fuel among eco-friendly fuels. Natural gas production is limited, and in Korea, it is supplied and utilized in the form of liquefied natural gas (LNG). In the case of LNG, the vaporization point is 163 degrees below zero, so ordinary metal cannot be used due to its brittleness. The International Maritime Organization (IMO) defines metals that can be used in the IGC Code, and is used for storage containers, transportation containers, etc. based on the metals. Welding is essential in the manufacture of large structures such as LNG storage tanks. In this study, weldability studies related to cryogenic materials were conducted. In Part I of this study, high-manganese steel and part II were studied for two types of stainless steel (STS304L, STS316L), and in Part III, aluminum (AL5083). During laser welding, the shape of the Bead on Plate (BOP) was analyzed, and a total of nine cases were analyzed using laser power and welding speed as variables. It was confirmed that the penetration and the width of the welding width were linearly proportional to the amount of heat input. Based on this study, it is possible to conduct a follow-up study to find the optimal welding conditions for butt welding and fillet welding.

자연재해 발생을 예방하기 위한 방재센서 기술이 중요하며 광섬유를 이용한 센서에 대한 관심이 높아지고 있다. 본 논문은 광섬유 센서 내장 탄소섬유시트로 보강된 RC보의 계측된 데이터로 결함 탐지 연구를 수행하였다. 미분의 국부적 변동 특성을 이용한 Method Ⅰ과 컨벌루션 방법을 이용한 Method Ⅱ를 비교, 분석하였다. 다른 차원의 데이터를 비교하기 위해서 무차원화 시켰으며, 분석 결과 Mehtod Ⅱ가 결함의 위치를 예리하게 잘 탐지하는 것으로 나타났다. Method Ⅱ인 컨벌루션에 사용 되는 필터 벡터를 잘 응용하면 더 좋은 효과를 기대할 수 있을 것으로 판단된다.

In a previous paper, ambient vibration tests were conducted on a cable stayed bridge with resilient-friction base isolation systems (R-FBI) to extract the dynamic characteristics of the bridge and compare the results with a seismic analysis model. In this paper, a nonlinear seismic analysis model was established for analysis of the bridge to compare the difference in seismic responses between nonlinear time history analysis and multi-mode spectral analysis methods in the seismic design phase of cable supported bridges. Through these studies, it was confirmed that the seismic design procedures of the “Korean Highway Bridge Design Code (Limit State Design) for Cable Supported Bridges” is not suitable for cable supported bridges installed with R-FBI. Therefore, to reflect the actual dynamic characteristics of the R-FBI installed on cable-supported bridges, an improved seismic design procedure is proposed that applies the seismic analysis method differently depending on the seismic isolation effect of the R-FBI for each seismic performance level.

This experiment was aimed to identify concentrations of mineral nutrients in leaf lettuce (Lactuca sativa) grown on hydroball aquaponics and in the water for growing fish by conducting two experiments. The experiment I (Expt. I) was conducted with 12 fishes (F12) with and without filter, hydroball and plants (H12 (12 fishes, hydroball), FHP12 (12 fishes, filter, hydroball, 6 plants) and HP12 (12 fishes, hydroball, 6 plants)), and the experiment II (Expt. II) was with and without plants (FH15 (15 fishes, filter, hydroball), FHP15 (15 fishes, filter, hydroball, 6 plants)). The pH level in the water of all the treatments was decreased during the growing period, and the pH and EC of the water were lower in all the treatment with plants than those without plants in both Expt. I and Expt. II. When compared with adequate nutrient concentrations for hydroponics, nitrate nitrogen (NO3-N) and phosphorus (P) concentrations in the fish growing water were higher under the FHP15 treatment in Expt. II; however, potassium (K), calcium (Ca), and magnesium (Mg) were only 16, 49, and 82% of hydroponics, representatively, and iron (Fe) was not detected. The fresh weight of lettuce harvested from the FHP15 treatment was 38 g, only a 30% of marketable lettuce yield. The T-N and P contents of the leaf tissue grown under the FHP15 treatment were close to the optimal level; however, the K, Ca, and iron (Fe) contents were less than the optimal with no deficiency symptom.

The purpose of this study was to compare the earth science curriculums of South Korea and North Korea. Aspects such as the content of the curriculums and the timing of learning were analyzed, in order to provide basic data that can be used to design a revised and integrated Korean curriculum. The objects of this study were South Korean Science textbooks from grades 5-9, and the high school Unity of Science and Earth Science I and II textbooks. Additionally, from North Korea, the junior middle school Natural Science 1 and 2 textbooks and the senior middle school Chosun Geography 2 and Geography 1 textbooks were analyzed. The results of this study obtained through an analysis that used the Trends in International Mathematics and Science Study (TIMSS 2019) grade 8 earth science assessment framework were as follows. First, South Korea needs to adopt iterative learning. Repetitive learning, which is effective for understanding what is being learned, is applied to only 1 by 8th grade. Second, South Korea needs to adjust the time when certain content is learned. This is because there is a disparity between when content is learned in comparison to North Korea, and the timing of learning of about 50% of the TIMSS standards have not been followed. Third, it is necessary to reflect the content present within the TIMSS that have not been learned. This can be a way to increase the nations’ educational competitiveness in the international community. This paper proposed a comparative analysis of South korean and North Korean approaches to the earth science curriculum and conducted practical research to facilitate the construction of an integrated curriculum.

본 연구는 진도 첨찰산을 대상으로 보전가치가 큰 난온대 상록활엽수림의 식생구조를 정량적으로 파악함과 동시에 변화상을 규명하고자 진행하였다. TWINSPAN과 DCA에 의한 군락분류결과, 구실잣밤나무군락(Ⅰ), 구실잣밤나무-참가시나무군락 (Ⅱ), 붉가시나무-구실잣밤나무군락(Ⅲ), 낙엽활엽수-상록활엽수혼효군락(Ⅳ)으로 구분되었다. 조사된 진도 첨찰산 상록활엽 수림의 전체 MIP분석 결과, 교목층에서 구실잣밤나무, 참가시나무, 붉가시나무, 아교목층에서 동백나무, 광나무, 생달나무, 관목층에서 마삭줄, 동백나무, 구실잣밤나무가 우점하고 있었다. 주요 상록수종을 대상으로 흉고직경급별 분포를 분석하여 과거 자료와 비교한 결과, 상층을 우점하고 있는 구실잣밤나무, 붉가시나무는 대경목 비율이 늘어난 반면, 아교목성상의 동백나 무, 광나무의 흉고직경급별 분포 차이는 나타나지 않았다. 향후 진도 첨찰산 상록활엽수림의 보전을 위해서는 천연기념물 보호구 역을 중심으로 정밀현존식생도 제작과 함께 실제 상록활엽수 분포지역을 파악한 후, 유역권 개념이 포함된 첨찰산 상록활엽수 림의 보호구역 재설정이 필요하다고 판단된다.

본 연구는 무등산국립공원 옛길 제2구간의 식생구조를 파악하기 위해 시행되었다. 총 60개의 조사구를 설치 및 조사하여 TWINSPAN과 DCA를 통해 군락을 분류한 결과 총 5개의 군락으로 분류되었다. 군락Ⅰ은 낙엽활엽수군락, Ⅱ는 소나무-졸 참나무군락, Ⅲ은 졸참나무군락, Ⅳ는 비목나무군락, Ⅴ는 신갈나무군락으로 최종 분류되었다. 분류된 군락들은 해발고에 따른 우점종의 분포가 뚜렷하게 나타났다. 군락 Ⅳ를 제외한 4개의 군락은 교목층의 수종이 우점하는 가운데 아교목층에서 때죽나무가 우점하는 현재의 군락의 형태가 유지될 것으로 판단된다. 한편, 군락 Ⅱ~Ⅳ의 관목층에 발달한 조릿대는 일시개화 및 고사 이후 하부식생 천연갱신에 대한 모니터링이 필요할 것이다. 군락 Ⅱ의 소나무-졸참나무간의 경쟁관계는 장기적인 측면에서 소나무군락의 세력 감소에 대한 관찰이 요구된다. 옛길 2구간은 해발고별 식생의 변화가 뚜렷하고 무등산국립공원의 깃대종인 털조장나무가 자생하는 등 생태적으로 가치가 높은 탐방로로써, 지속가능한 이용을 통해 우수한 산림생태계를 보전하여야 한다.

본 논문은 미국의 대 아프리카 외교정책을 분석하고 있다. 이 논문에서는 미국과 아프리카 관계가 그동안 큰 진전을 보이지 못한 요인들이 무엇인지 살펴보고 있다. 일부 전문가들은 미국과 아프리카의 협력이 포괄적이며 꾸 준히 진전되고 있다고 주장한다. 그러나 이 논문은 미국이 아프리카에 대한 장기적이고 전략적인 정책과 비전이 부재하기 때문에 미국과 아프리카 관계 는 발전하지 못하고 있다는 점을 지적하였다. 9/11테러 이전 미국의 대아프 리카 정책은 인도주의적인 원조와 초국가적 범죄, 테러, 그리고 고질적인 질병 치료 지원 단기적인 협력과 같은 분야에만 국한되었다. 그러나 9/11테 러 이후 미국은 테러의 확산과 안보 위협의 증가를 막고, 지정학적, 경제적 으로 중요한 지역에 대한 통제, 그리고 자원과 시장에 대한 이유로 아프리 카에 대해 적극적으로 개입하기 시작하였고, 그 결과 미국의 아프리카에 대 한 직접 투자의 증가, 아프리카의 정치, 보건, 민주화의 개선 등이 이루어지 고 있다. 현재 미국과 아프리카 관계는 후원자와 고객 사이의 관계에서 동 등한 협력 방식으로 변화하고 있으며 이러한 추세는 지속될 것이다.

2 (Langmuir, Freundlich, Elovich, Temkin, and Dubinin-Radushkevich) and 3 (Sips and Redlich-Peterson)-parameter isotherm models were applied to evaluated for the applicability of adsorption of Cu(II) and/or phosphate isotherm using chitosan bead. Non-linear and linear isotherm adsorption were also compared on each parameter with coefficient of determination (R2). Among 2-parameter isotherms, non-linear Langmuir and Freundlich isotherm showed relatively higher R2 and appropriate maximum uptake (qm) than other isotherm equation although linear Dubinin-Radushkevich obtained highest R2. 3-parameter isotherm model demonstrated more reasonable and accuracy results than 2-parmeter isotherm in both non-linear and linear due to the addition of one parameter. The linearization for all of isotherm equation did not increase the applicability of adsorption models when error experiment data was included.

Microalgae and cyanobacteria are photosynthetic microorganism used as human nutrients. Light is the most important factor affecting the biomass accumulation and production of bioactive compound by photosynthetic microorganisms. However, excessive light can suppress their growth by damaging the photosynthetic machinery such as Photosystem II (PS2). Therefore, an LED-based illumination system that is used for cultivation of photosynthetic cells needs a device to appropriately regulate the light level, but the addition of an electronic dimmer increases the initial costs. Spirulina is one of the promising and representative photosynthetic microorganisms. In the present study, we describe the use of a new semicylindrical column photobioreactor for cultivation of Spirulina. The amount of incident light reaching the photobioreactor was easily adjusted by changing angle of the LED in relation to the flat surface of the bioreactor. Arrangement of the LED bar at a 45° angle led to the highest growth and chlorophyll content, and led to no retardation of cell growth during the initial growth phase.

PURPOSES : The objective of this study is to figure out the trend and characteristics of fine particulate matter (PM2.5) and nitrogen oxide (NOx) concentration in underpass sections. The effect of traffic and meteorological condition on PM2.5 / NOx concentration was analyzed using field monitoring data. METHODS : Based on the literature review, PM2.5 and NOx concentration data were monitored using DustTrak II aerosol monitoring system and Serinus 40 oxides of nitrogen analyzer, respectively. Meteorological and traffic information was collected using automatic weather system and traffic volume counter, respectively. RESULTS : PM2.5 has a positive and negative correlation with relative humidity and wind speed, respectively. Meanwhile, NOx was found to have no correlation with meteorological conditions. The NO/NO2 ratio tends to change with traffic volume, indicating higher correlation between NO and traffic volume; the observed NO2 is mostly a secondary material produced by NO oxidation. CONCLUSIONS : Our study provides clear characteristics of NOx and PM2.5 and correlations with meteorological and traffic information in the underpass sections. It is found from this study that the increase in wind speed causes reduction in the concentration of PM2.5 owing to the diffusion and dispersion phenomena. On the other hand, the meteorological conditions were found to barely have correlations with NOx concentrations in this study. The traffic volume could significantly affect the NOx concentration and NO / NO2 ratio, which is directly correlated to the emissions from vehicles.

건설공사의 클레임(claim)은 공사진행과 관련하여 계약 당사자간의 권리 의무관계를 명확하게 정리하여 추가적으로 발생하는 시공비용 부담자를 결정하는 것을 말한다. 건설 공사는 현장이 매우 복합하고 예기치 못한 현상의 발생, 발주처의 요구 등으로 인한 계 약변경과 세계경제 변동 등으로 위험성을 항상 내포하고 있다. 이러한 불확실성과 위험 성은 다양한 이익 집단이 참여하는 공사과정에서 당사자 간의 갈등을 발생시키고 클레 임이나 분쟁을 발생하게 한다. 현장에서 발생되는 클레임의 유형은, ⅰ) 계약도서와 현장 조건의 상이, ⅱ) 발주자 측의 시공내용 변경지시, ⅲ) 공사의 지연, ⅳ) 발주자 측의 공사 수행의 독촉 행위 등이 있으며, 이에 대한 개선방안으로 첫째, 클레임 예방 제도 도입이며 세부적으로 ⅰ) 리스크 관리 예산 확보, ⅱ) 실질적 감사제도 확립, 둘째, 클레임 예방을 위한 계약제도 정비이며, 세부적으로 ⅰ) 발주방식에 적합한 공사계약특수조건 구비, ⅱ) 공사계약 일반조건의 개선, 셋째, 분쟁 전 단계별 협의 체계 수립이며 세부적으로, ⅰ) 클레임 발생 단계의 처리, ⅱ) 의견차이 단계의 처리, ⅲ) 논쟁 단계의 처리가 필요하며 이에 대한 제도의 보완이 필요함을 제언한다.