The spectrum of this study was research on the closed hydroponic cultivation of netted melons (Cucumis melo L.) using coir substrate, analyzing the impact of this cultivation method on melon yield, fruit quality, and the efficiency of water and nutrient usage. The experimental results showed that the average fruit weight of the melons grown in a closed system was 71.4 g higher than that of the open system, and the fruit width was on average 0.2 cm larger, showing a statistically significant difference. However, there was no difference in the average sugar content of the fruit flesh and height. Although there is no substantial commercial difference, it is conjectured that the change in the macronutrients ratio in the irrigation has played a role in the statistically significant increase in fruit weight, which is attributed to changes in the crops' nutrient uptake concentrations. This necessitates further research for a more comprehensive understanding. In terms of the productivity of irrigation required to produce the fruit, applying the closed system resulted in an increase of 7.6 kg/ton compared to the open system, saving 31.6% of water resources. Additionally, in terms of nutrients, cultivating in a closed system allowed for savings of approximately 59, 25, 55, 83, 76, and 87% of N, P, K, Ca, Mg, and S, respectively, throughout the entire cultivation period. As the drainage was reused, the ratios of NO3 - and Ca2+ increased up to a maximum of 9.6 and 9.1%, respectively, while the ratios of other ions gradually decreased. In summary, these results suggest that closed hydroponic cultivation can effectively optimize the use of water and fertilizer while maintaining excellent fruit quality in melon cultivation.

Melon fruits exhibit a wide range of morphological variations in fruit shape, sugar content, net quality, diameter and weight, which are largely dependent on the variety. These characteristics significantly affect marketability. For netted varieties, the uniformity and pattern of the net serve as key factors in determining the external quality of the melon and act as indicators of its internal quality. In this study, we evaluated the effect of fruit morphology and growth on netting by analyzing the changes in melon fruit quality under LED light treatment and monitoring fruit growth. Computer vision analysis was used for quantitative evaluation of fruit net quality, and a three-variable logistic model was applied to simulate fruit growth. The results showed that melons grown under LED conditions exhibited more uniform fruit shape and improvements in both net quality and sugar content compared to the control group. The results of the logistic model showed minimal error values and consistent curve slopes across treatments, confirming its ability to accurately predict fruit growth patterns under varying light conditions. This study provides an understanding of the effects of fruit shape and growth on net quality.

In this study, the effect of crown heating on the cultivation environment, budding, flowering and yields of strawberry was analyzed. In December, January, and February, when the outside temperature was low, the average strawberry crown temperature at daytime in the test zone was 1.3°C higher than that in the control zone, and the average strawberry crown temperature at nighttime in the test zone was 2.7°C higher than that in the control zone. The average bed temperature at daytime in test zone was 1.7°C higher than that in the control zone, and the average bed temperature at nighttime in test zone was 2.4°C higher than that in the control zone. As a result of performing correlation analysis and regression analysis on strawberry crown temperature and budding period, the correlation coefficient was -0.86, which tended to be shorter as the crown temperature was higher, and the determination coefficient was 0.74. The total yields of strawberry during test period were 392.6 g/plant for test greenhouse and 346.0 g/plant for control greenhouse respectively. As for the quality of strawberries, the ratio of 2L (very large) grades and L (large) grades was 62.4% in the test greenhouse and 58.5% in the control greenhouse, indicating that the proportion of high quality strawberries was higher in the test greenhouse.

YSZ (Y2O3-stabilized zirconia)-based ceramics have excellent mechanical properties, such as high strength and wear resistance. In the application, YSZ is utilized in the bead mill, a fine-grinding process. YSZ-based parts, such as the rotor and pin, can be easily damaged by continuous application with high rpm in the bead mill process. In that case, adding WC particles improves the tribological and mechanical properties. YSZ-30 vol.% WC composite ceramics are manufactured via hot pressing under different pressures (10/30/60 MPa). The hot-pressed composite ceramics measure the physical properties, such as porosity and bulk density values. In addition, the phase formation of these composite ceramics is analyzed and discussed with those of physical properties. For the increased applied pressure of hot pressing, the tetragonality of YSZ and the crystallinity of WC are enhanced. The mechanical properties indicate an improved tendency with the increase in the applied pressure of hot pressing.

This study examines the characteristics of berries from secondary bearing shoots of ‘Scintilla’ southern highbush blueberry, grown hydroponically in the Jinju, Gimhae, and Uiryeong regions of Gyeongnam Province. Typically, ‘Scintilla’ forms flower buds at the tips of regular bearing shoots during the previous season, yielding berries in the current season. However, under heated cultivation, we observed a proliferation of secondary bearing shoots that produce berries in the same growing season. Flowering and harvesting on secondary bearing shoots were delayed by 52 and 36 days, respectively, compared to regular bearing shoots. However, these shoots exhibited a 54% increase in diameter and a 10% increase in length. We found no significant difference in berry size and soluble solid content between the two types of shoots. Notably, berries from the secondary bearing shoots had higher potassium and lower calcium and magnesium concentrations. We conclude that berries from secondary bearing shoots could be marketable, provided the bushes are healthy. These findings provide valuable insights for optimizing cultural practices to improve the yield and quality of blueberries under specific environmental conditions.

This research aims to validate the effectiveness of the "Specialized Entrepreneurship University Program," which was conducted as part of government entrepreneurship support initiatives from 2018 to 2022. Based on previous studies, a research model was derived consisting of three laboratory entrepreneurship support factors that influence program satisfaction and entrepreneurial outcomes (infrastructure support, educational mentoring support, and business linkage support). Surveys were collected and analyzed from 126 laboratory entrepreneurship firms participating in the program, and empirical analysis of the research model was conducted using SPSS 23.0 statistical software. The analysis results indicated that the three variables, namely infrastructure support, educational mentoring support, and business linkage support, were significant factors affecting program satisfaction, and program satisfaction was confirmed to influence entrepreneurial outcomes. Furthermore, it was found that the three business operation factors indirectly influenced entrepreneurial outcomes by partially mediating program satisfaction. This study is considered significant as an empirical study for the initial stage of the second-phase program enhancement, verifying the effectiveness of laboratory entrepreneurship support factors. The findings can be applied to similar government entrepreneurship support initiatives and contribute to the effective strategy and planning of stakeholders involved. The limitations of this study include the need for further research on the perception of the extent to which it contributes to entrepreneurial outcomes, emphasizing caution in interpreting the research model, and the necessity for expanding the survey population and improving survey items in future research.

철근콘크리트는 가장 널리 사용되는 건축자재로 최근 노후 시설물이 증가하면서 노후 구조물에 대한 안전성 검토가 매우 중요한 문제로 대두되고 있다. 본 연구에서는 대표적인 열화 인자인 동결융해와 철근부식 그리고 동결융해와 철근부식의 복합적 열화에 따른 RC 휨 부재의 거동을 실험적으로 평가하였다. 4개의 철근콘크리트 휨 부재를 제작하였으며 각 열화 인자에 따른 RC 휨 부재의 거동을 평가하기 위해 4점 재하법을 이용하여 정적실험을 수행하였다. 동결융해는 총 300 사이클의 급속동 결융해실험을 수행하였으며, 부식은 전위차부식촉진실험을 수행하였다. 실험 결과, 동결융해로 인해 콘크리트의 압축강도가 12% 감소하였으며 RC 보 부재의 상부 압축부의 파쇄 범위가 증가하였고 최대강도가 6% 감소하였다. 철근부식으로 인해 RC 휨 부 재의 항복강도가 1.2%, 최대강도가 7% 감소하였으며, 복합열화로 인해 RC 휨 부재의 항복강도가 2.4%, 최대강도가 9% 감소하 였다.

우리나라 해양환경에 유출되는 위험·유해물질(Hazardous Noxious Substances, HNS)의 해양환경 및 사회환경 영향평가 결과 와 HNS 확산 영역, 해양환경 정보, HNS 실태조사 결과 등 관련 연구 결과 및 자료를 정책결정자와 연구자들에게 공유할 수 있는 HNS 국내 용 플랫폼을 구축하고자 한다. 국내의 HNS 관리 및 배출 체계 마련을 위한 의사결정 지원이 가능하고 국내 실정에 적합한 플랫폼의 설계 를 위하여 유해물질의 데이터 관리 및 유출 시 대응 도구, 기초적인 정보 등 플랫폼에 관련된 기술동향을 분석하는 등 국내·외의 플랫폼 개발 사례를 고찰하였다. 유속 벡터의 전처리 기능 개발, 전처리 결과에 따른 동적 시각화 구현, 해양산업시설 배출 HNS의 유출량과 유출 범위의 전처리 모듈, HNS 해양환경 영향평가 연산 모듈 프로토타입을 개발하였다. HNS 해양환경 영향평가를 위한 국내용 HNS 플랫폼은 초기 위해성을 평가하고 대응 및 관련 법제화 시 과학적인 기초 도구로써 활용될 수 있을 것으로 기대된다.

본 연구에서는 GFRP(Glass Fiber Reinforced Polymer)를 주 보강근으로 사용하였으며, 정착길이가 없는 시험체를 제작 하여 4점 재하 휨시험을 수행하였다. 각 변수는 공칭지름이며 공칭지름 D13, D16, D19, 총 3가지의 변수로 이루어져있다. 휨 모 멘트는 공칭지름이 커질수록 약24.17%, 45.92% 강도가 증가하였으나 공칭 휨 강도를 고려하였을 때, 인장 강도와는 달리 공칭 지름에 비례하여 유사한 성능을 나타냄을 알 수 있었다. LVDT로 보강근과 콘크리트와의 부착성능을 확인하였고, 그 값은 매우 미미하며 거의 발생 되지 않은 것으로 판단된다. 또한 DIC로 시험체의 처짐을 확인하였으며, 실세 처짐 값과 유사함을 알 수 있었다.

본 논문은 직류전동기(DC motor)와 전기적인 특성은 유사하지만, 수명과 신뢰성이 향상된 BLDC 모터의 제어기법에 대해 언 급하고 있다. BLDC모터는 회전자의 위치 정보를 사용하여 직류전동기의 기계적인 접촉에 의한 정류 장치를 제거함으로써 내구성과 속도 안정성을 향상시킬 수 있다. 본 연구에서는 BLDC모터의 권선에 흐르는 전류가 직류전동기의 전기자에 흐르는 구형파 형태의 전 류인 것에 착안하여 직류전동기에 대한 제어기를 설계하고, 설계된 제어기를 3상 BLDC모터에 적용하여 제어기의 유효성을 확인하였 다. 이를 위해 3상 BLDC모터의 전기적인 파라미터 값을 가지는 단상 직류전동기의 모델링을 실시하였고, 도출된 시스템에 대해 근궤 적법을 적용하여 전동기의 속도제어를 위한 PI 제어기를 설계하였다. DC 전동기의 속도제어 시뮬레이션을 시행하여 제어기의 성능을 확인하였고, 동일한 제어기를 MATLAB으로 구현한 3상 BLDC모터의 속도제어에 적용하였다. DC 전동기와 유사한 제어 결과를 3상 BLDC모터에서 얻을 수 있었고, 이를 통해 연구에서 제안한 제어기법의 유용성을 확인할 수 있었다.