Recently, steel dampers are widely used as seismic reinforcement devices. Steel dampers have the advantage of being easy to manufacture and being able to absorb a lot of energy through stable hysteresis behavior. However, there is a possibility that the steel damper may be damaged due to fatigue caused by repeated seismic loads. In this study, the seismic performance of steel dampers and engineering plastic dampers with different physical characteristics were compared and analyzed. In addition, numerical analysis was performed on a hybrid damper that combines a steel damper and an engineering plastic damper. It is more effective to apply engineering plastic dampers to structures that experience significant displacement due to seismic loads. The behavior of hybrid dampers combining steel dampers and engineering plastic dampers is dominated by steel dampers. A hybrid damper in which an engineering plastic damper yields after a steel damper yields can effectively respond to various seismic loads and secure high ductility and excellent seismic performance.

In this study, the relationship between the color of the pigment added to the plastic resin and the size of the fractured part of the specimen was confirmed when processing ABS plastic tensile specimens using a sealed 3D printer. Through the test, it was confirmed that the fracture dimension existed in the range of 13.104 to 13.138 ㎜ and there was no significant difference in dimension according to the color of the additive, and the null hypothesis was adopted. In addition, it was confirmed that a significant difference occurred in the order of red, black, white, and green colors.

This study was conducted to prepare a plan for the controlling indoor microclimate environment using natural ventilation for the single-span plastic greenhouses, which account for about 83.8% of the total area of horticultural greenhouses in South Korea. The changes of indoor air temperature and relative humidity according to the side opening height were experimentally compared and analyzed in the experimental greenhouse. As the side opening height was changed to 30, 70, and 110cm, the indoor and outdoor temperature differences were found to be 14.0, 10.1, and 7.7℃, respectively. The indoor and outdoor relative humidity differences were found to be -15.7, -12.5, and -11.1%, respectively. These results were verified for statistical significance by ANOVA. When the variable breadth of the outdoor temperature was 6.9℃, the indoor temperature breadths were 14.5, 12.3, and 9.0℃, and when the outdoor relative humidity breadth was 24%, the indoor relative humidity breadths were 31.2, 28.0, and 23.8%, respectively. It was analyzed that as the side opening height is increased, the indoor temperature and relative humidity become similar to the outdoor environment. This is because the air is mixed by active indoor-outdoor air movement of greenhouses with natural ventilation. The results indicated that the proper opening and closing of side openings is necessary for the stable indoor microclimate environment control of plastic greenhouses.

Plastics are widely used in industries in human society and because of their structural stability, degradation is a serious global issue. To estimate the degradation of plastic, 31 edible mushrooms were cultured with the selected plastic films (polyethylene [PE], polystyrene [PS], and poly(ethylene terephthalate) [PET]) for 3 months at 25 °C. Measuring the weight of the films showed that four species of mushrooms, namely Porostereum spadiceum, Ganoderma lucidum, Coprinellus micaceus, and Pleurotus ostreatus, exhibited the highest degrees of plastic degradation. In addition, the mushrooms and fungi that exhibited the most significant plastic degradation were cross-cultured to promote this degradation. As a result, cross-cultivation of G. lucidum and Aspergillus niger showed a weight loss of 2.49% for the PET film. For the PS film, Aspergillus nidulans showed a weight loss of 4.06%. Cross-cultivation of A. nidulans and C. micaceus, which showed a weight loss of 2.95%, was noted as an alternative for PS biodegradation, but is harmful to humans. These bio-degradation effects of edible mushroom will contribute to the development of alternatives for eco-friendly plastic degradation.

본 연구의 목적은 컨테이너 육묘 시스템을 활용한 참외 접목 묘의 안정적인 생산 가능성을 평가하는 것이었다. 이를 위해, 컨테이너 육묘 시스템과 고온 조건의 플라스틱 온실에서 육묘 한 접수와 대목, 접목묘의 생육을 비교 분석하였다. 접목활착 후 육묘 환경에 따른 참외 접목묘의 생육과 묘소질을 0일, 4일, 7일, 11일, 14일째에 비교하였다. 컨테이너 육묘 시스템에서 는 주야간 온도를 25/20°C, 상대습도를 70%로 설정하여 재 배기간 동안 안정적으로 유지하였으며, 플라스틱 온실 내의 주야간 평균온도는 28.1/15.4°C로 주야간 온도차(DIF)가 더 크게 나타났다. 조사기간 동안 참외 접목묘의 초장은 플라스 틱 온실 육묘 처리구에서 컨테이너 육묘 시스템 처리구보다 더 길게 나타났다. 참외 접목묘 조직의 충실도는 지상부 건물 중을 초장으로 나누어 계산하였다. 육묘장에서 접목한 묘는 접목 후 7－10일 경과하여 활착이 완료되고 초장이 10cm 내 외일 때 출하하여 정식에 이용되게 된다. 본 연구에서 접목활 착 후 7일째에 컨테이너 육묘 시스템에서 재배된 묘의 충실도 는 44.9±2.64mg/cm으로 나타났으며, 플라스틱 온실 육묘 처 리구에서는 24.4±1.56mg/cm로 나타났다. SPAD 평균은 플 라스틱 온실 육묘에서 30.5, 컨테이너 육묘 시스템에서 41.1 로 측정되었다. 이러한 결과는 컨테이너 육묘 시스템의 활용 이 고온기 또는 저일조 시기와 같은 육묘 환경에서도 고품질 모종을 안정적으로 생산할 수 있는 것을 확인하였고, 인공광 을 이용한 육묘 시스템의 활용 범위가 앞으로 더 확대될 것으 로 기대된다.

The tribology characteristics of the graphene coated PA6 were evaluated with scratch experiments. As a result, the following conclusions were obtained. The PA6 of the graphene coating shows a 0.1 improvement in friction coefficient and a lower abrasion depth than PA6 in the variable pressure-type scratch experiments. PA6 of the graphene coating showed a lower friction coefficient of 0.2 or more than PA6 in the friction coefficient in the static pressure scratch experiments, indicating that wear resistance was improved. In both the variable and the static pressure type scratch experiments, the tip depth of graphene-coated PA6 shows a thinner wear depth than PA6, showing the effect of graphene. The graphene content showed excellent tribology characteristics at 3%, and there was no difference in tribology characteristics at higher contents.

플라스틱은 전세계적으로 사용량이 증가함에 따라 해양 환경으로 유입되는 플라스틱 쓰레기의 양도 꾸준히 증가하고 있으며, 미세플라스틱은 해양 생물에 의해 섭취되어 소화관에 축적됨에 따라 성장과 생식에 유해한 영향을 미친다. Cytochrome P450 (CYP)는 환경 오염물질을 대사하 는 해독효소로 알려져 있으나 지각류에서는 그 기능에 대해서는 잘 알려져 있지 않다. 본 연 구에서는 기수산 물벼룩 Diaphanosoma celebensis에서 clan 2, 3, 4에 각각 속하는 CYP 유전자 9종(clan 2: CYP370A4, CYP370C5; clan 3: CYP350A1, CYP350C5, CYP361A1; clan 4: CYP4AN-like, CYP4AP2, CYP4AP3, CYP4C33-like1)의 서열에 대해 진화적으로 보존된 서열의 유사도를 분석 하고 계통분석을 실시하였다. 또한 3종류의 서로 다른 크기의 polystyrene beads (0.05-, 0.5-, 6-μm PS beads; 0.1, 1, and 10 mg/L)에 48시간 노출된 기수산 물벼룩에서 이들 9종의 CYP 유 전자의 발현을 real time reverse transcription polymerase chain reaction (RT-PCR)로 분석하였 다. 결과적으로 기수산 물벼룩 CYP 유전자는 모두 진화적으로 보존된 motif를 가지고 있으며 계통분석 결과 각각 clan 2, 3, 4에 속하는 것으로 확인되었다. 이는 기능적으로 보존되어 있음 을 의미한다. CYP 유전자 중 clan 2에 속하는 CYP370C5와 clan 3에 속하는 CYP360A1, 그리고 clan 4에서는 CYP4C122 유전자의 발현이 0.05-μm PS beads에 노출되었을 때 유의하게 증가 하는 양상을 보였으며, 이는 이들 유전자가 PS 대사에 관여한다는 것을 의미한다. 본 연구는 미세플라스틱이 해양 무척추 동물에 미치는 생물 영향을 분자적 수준에서 이해하는데 도움이 될 것이다.

The need for lightweight yet strong materials is being demanded in all industries. Carbon fiber-reinforced plastic is a material with increased strength by attaching carbon fiber to plastic, and is widely used in the aerospace industry, ships, automobiles, and civil engineering based on its low density. Carbon-reinforced fiber plastic is a material widely used in parts and manufactured products, and structural analysis simulation is required during design, and application of actual material properties is necessary for accurate structural analysis simulation. In the case of carbon-reinforced fiber plastics, it is reported that there is a porosity of around 0.5% to 6%, and it is necessary to check the change in material properties according to the porosity and pore shape. It was confirmed by applying the method. It was confirmed that the change in elastic modulus according to the porosity was 10.7% different from the base material when the porosity was 6.0%, and the Poisson's ratio was confirmed to be less than 3.0%. It was confirmed that the elliptical spherical pore derived different material properties from the spherical pore depending on the pore shape, and it was confirmed that the shape of the pore had to be confirmed to derive equivalent material properties.

Tomatoes in greenhouse are a widely cultivated horticultural crop worldwide, accounting for high production and production value. When greenhouse ventilation is minimized during low temperature periods, CO2 enrichment is often used to increase tomato photosynthetic rate and yield. Plant-induced electrical signal (PIES) can be used as a technology to monitor changes in the biological response of crops due to environmental changes by using the principle of measuring the resistance value, or impedance, within the crop. This study was conducted to investigate the relationship between tomato growth data, vital response, and PIES resulting from CO2 enrichment in greenhouse tomatoes. The growth of tomato treated with CO2 enrichment in the morning was significantly better in all items except stem diameter compared to the control, and PIES values were also higher. The growth of tomato continuously applied with CO2 was better in the treatment groups than control, and there was no significant difference in chlorophyll fluorescence and photosynthesis. However, PIES and SPAD values were higher in the CO2 treatment group than control. CO2 enrichment have a direct relationship with PIES, growth increased, and transpiration increased due to the increased leaf area, resulting in increased water absorption, which appears to be reflected in PIES, which measures vascular impedance. Through this, this study suggests that PIES can be used to monitor crops due to environmental changes, and that PIES is a useful method for non-destructively and continuously monitoring changes of crops.

This study aimed to develop an optimal greenhouse model for strawberry seedling during the summer high-temperature period based on the results of field surveys. We conducted a survey on the structure types of 46 strawberry seedling farms nationwide, including width, ridge height, eaves height, ventilation method, seedling bed width, and spacing. Based on the survey results, we derived the optimal greenhouse model by considering various factors. The greenhouse width was set at 14 meters to maximize the efficiency of seedling beds and overall space. The height was determined at 2 meters, taking into account ventilation during the summer season. To reduce stress on the supporting structure due to snow loads, we established a reinforcement installation angle of 50 degrees. We analyzed two different models that use support beams with dimensions of φ48.1×2.1t and φ59.9×3.2t, respectively, to ensure structural safety against meteorological disasters, considering regional design wind speeds and snow accumulation. We utilized these developed greenhouse model to conduct strawberry seedling experiments, resulting in a high survival rate of average 93.2%. These findings confirm the usefulness of the strawberry seedling greenhouse in improving the seedling environment and enhancing overall efficiency.

미세플라스틱 입자는 환경 내 어디에나 존재하며 크기, 모양 또는 유형의 표준화된 입자가 아 니다. 따라서 독성자료를 바탕으로 해수, 퇴적물 등 해양환경의 다차원을 정확하게 평가하고 관리하는 위험평가 프레임워크를 구축하는 것은 매우 어렵다. 본 연구에서는 해양환경 미세플 라스틱의 특징과 영향을 조사하였고, 해양환경 미세플라스틱의 분포와 생물영향에 따른 위해 도 평가 프레임워크(초안)를 제안하고 있다. 환경 미세플라스틱의 특성은 매우 다양하지만 대 부분의 독성 데이터는 독특한 형태와 유형에 집중되어 있으며, 실험실 노출 생물과 관리해야 하는 생물 종도 다르다. 실제적으로, 지금까지의 수집된 연구결과는 위해성평가에 활용하기에 독성 데이터 품질에 있어 불확실성이 높기도 하며, 전통적인 위해성평가 프레임워크를 적용 하는 데 있어 고려할 부분이 많이 존재한다. 그러나, 현재 미세플라스틱 관리에 대한 국제사회 의 움직임이 점차 강화되고 있고, 해양환경의 미세플라스틱 오염도가 높아지고 있는 점을 고 려하면, 해양환경의 미세 플라스틱 특성에 기초한 위해성평가 기법 구축에 대한 추가 연구가 제안되어야 할 것이다.

본 연구에서는 형광측정기법을 사용하여 태안반도 인근 8지점의 표층 해수 내 미세플라스틱 정량분포를 조사하였다. 연구결과 미세플라스틱의 검출범위는 0~360.5 particles/l (평균 149.7 ± 46.0 particles/l)로 나타났다. 하지만 해양환경 내 미세플라스틱의 정량분석방법이 표준화되지 않아 타 연구결과와 직접비교 하는 것이 불가능한 상황이다. 본 연구결과 검출된 미세플라스 틱을 크기별로 분류하면 < 50 μm 크기가 우점하지만, St. 3의 경우 > 500 μm이 25.6%를 차 지하여 지역별로 우점하는 미세플라스틱의 크기에 차이가 나타난다. 또한 채집지역, 저질의 종 류, 검출되는 플라스틱 크기에 따른 미세플라스틱의 검출량 비교에도 뚜렷한 상관관계를 가지 는 요인을 확인할 수 없었다. 이는 플라스틱의 재질에 따른 물리 · 화학적 특성, 해양의 동적 조건(해류, 바람, 파도, 조류 등), 지질학적 특성(지형, 경사 등), 연안 생물을 포함한 저질의 구성 및 특성, 상호작용, 인간활동(어업, 개발, 관광 등), 기상조건(홍수, 강우 등)과 같은 다양한 요인 이 미세플라스틱의 거동에 영향을 주기 때문이다. 그러므로 향후 정량분석방법 표준화 및 환 경요인에 대한 분석이 수반된 미세플라스틱 모니터링 기초연구가 필요한 상황이다.