• 한국도로학회논문집
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• 제17권5호
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• pp.67-73
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• 2015

PURPOSES : This study was conducted to derive the optimum mixing ratio of phosphorescent pigment for the development of phosphorescent line marking. METHODS: In this study, we utilized a literature review and case study methodology, to describe the domestic and foreign state of practice for the production and mixing of phosphorescent pigment for use in line marking. The optimal mixing ratio was derived by comparing the reduction in luminance over time for the various phosphorescent pigment mixing ratios identified in the literature. In addition, performance and construction characteristics were analyzed using field testing techniques. RESULTS : The results were as follows: 1) the results of the luminance performance standards tests showed that all of the phosphorescence test specimens satisfied the phosphorescent fire protection standard. As the phosphorescent pigment mixing ratio increased, the luminance value increased, 2) the luminance reduction rate was minimum at the mixing ratio of 50%. However, when compared to a mixing ratio 40%, a small difference was recorded, the luminance reduction rate from the mixing ratio of 40% is judged as being converged. Therefore, in view of the economic efficiency, it was determined that the optimal mixing ratio was 40%, 3) as a result of construction on the field, a mixing ratio of 40% was found to have a higher luminance value than the general line marking for up to three hours after sunset, 4) it was found that the phosphorescent line markings without glass beads spraying had a higher luminance value than the phosphorescent line markings with glass beads spraying. CONCLUSIONS : Through the results of the basic experiments of the line markings obtained by blending a phosphorescent pigment, the results could be applied to play an important role in the development of phosphorescent line marking paint technology and in establishing application planning for on-site construction characteristics.

• Journal of Biosystems Engineering
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• 제27권1호
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• pp.11-18
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• 2002

One of the major obstructing factors against managing dairy farm in Korea has been a shortage of roughage supply, which resulted in excessive abuse of concentrate feed. In order to solve this problem, production of the wrap silage by the winter cereal forages raised in the fallow paddy field is strongly recommended in Korea. The main objective is to develop a tractor attached round bale wrapper which can process the silage by wrapping the round bales with thin plastic films. This is the first half of the study which is divided by two parts. In this first part, bale wrapping process was analyzed, and based on this results the followings were designed, developed and tested. 1. Bale wrapper which haying the maximum capacity of 1 ton bale with various functions such as loading, wrapping, discharging the round bales and supplying and cutting wrap films was designed. 2. An actuator and its hydraulic circuit of each process were developed and tested. 3. Also, the variations of hydraulic pressure and engine speed were investigated by operating bale wrapper developed. In this test, maximum pressure of the hydraulic circuit for the bale wrapping was 130 kg/㎠ when it raised the bale, which was quite below the relief pressure of 170 kg/㎠ of hydraulic circuit. In the engine speed test, speed drop was 20∼67 rpm, which meant that there was no over-load operation. Therefore, the experiment proved that developed hydraulic circuit and mechanism is stable in bale wrapping operation

• 한국물환경학회지
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• 제38권6호
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• pp.267-274
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• 2022

This paper is a result of research conducted on the 800,000 m³/d capacity of A Water Treatment Plant (WTP) and 400,000 m³/d capacity of B WTP plant in operation in the Nakdong River region. We evaluated the effect of algae broom on the WTP operation based on the running data of both WTP and the data on the pre-oxidation process field test for algae control using sodium permanganate (SPM) at the B WTP. The study results showed that during the algal bloom period, the coagulant dose increased by 102% in A WTP and 58% in B WTP, respectively, and the chlorine dose also increased by 38% and 29%, respectively, which may affect Total trihalomethane (THM) production. Data such as algal populations and Chl-a, residual chlorine and THM, algal populations, and ozone dose appeared also highly correlated, confirming that algal broom affects WTP operations, including water quality and chemical dosage. As a result of the field test of B WTP, THMs appeared lower than that of the control, suggesting the possibility of the SPM pre-oxidation process as an alternative to algae-related water quality management. Furthermore, in terms of GHG emissions due to energy consumption, it was observed that the pre-oxidation process using SPM was approximately 10.8%, which is a very low ratio compared to the pre-ozonation process. Therefore, these results suggest that the SPM pre-oxidation process can be recommended as an alternative to low-carbon water purification technology.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.279-279
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• 2017

In Korea, the single span unheated plastic house cultivated crops from autumn to spring of the following year, removed the plastic film and frame, cultivated rice, set up a plastic house again and cultivated crops. The crops in the greenhouse are utilized mainly for the production of leaf vegetables such as lettuce, leek, and fruit vegetables such as strawberry, watermelon, oriental melon, etc. and raising high income. Because, the production of these crops has characteristics requiring a lot of labor and it is difficult to produce horticultural crops at unheated plastic houses as the rural population ages. Therefore, we conducted a test to develop a crop planting system to cultivate crops in single span unheated plastic houses, although the utilization of labor is less than that of horticultural crops. The prior cropping cultivated three cultivars of sweet potatoes early, the second produced cultivated sweet potatoes, corn and soybeans. In the cultivation of the previous cropping, the sweet potatoes were harvested on the 113th day after planting on March 30th, the yield was 822 kg/10a for Pungwonmi, 1,377 kg/10a for Jinhongmi, 1,483 kg/10a for the Dahomi. Because of differences, the yield of Pungwonmi cultivar was less than that other cultivars and the yield of open field cultivations, we will expect further research. In the cultivation of the succeeding crops sweet potatoes were planted on July 27 and harvested 110 days later and investigated. The product yield of Pungwonmi cultivar was 1,024 kg/10a, and the Jinhongmi, Dahomi cultivars were not at economic level for sale and were necessary to review. In succeeding-crops, corn tested the Ilmichal cultivar, seeded on 27th July, harvested on October 11th. The day of silking was 45 days after sowing, the yield was 1,156 kg/10a, the goods rate was 100% level. The beans in the succeeding cultivation crop were sowed on 27th July, the early maturing of the varieties coming to Hwangeumol and Saeol cultivar, on 17th October, the late maturing soybean Daewonkong cultivar were harvested on October 21st. The yield of early maturing two cultivars was 214 kg/10a, Daewonkong was 257 kg/10a, and 100 seeds weight which were more than the early maturing beans were also heavy. When calculating these incomes price-wise according to the harvest time, we were able to consider the income in the order of corn, sweet potato and soybean from the second term crop. Various studies such as varieties, mulching method, moisture management, control environment management, etc. are considered necessary to develop cropping systems with sweet potato and field crops in future unheated plastic house.

• 한국농공학회지
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• 제22권4호
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• pp.82-95
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• 1980

This paper complies the results of the studies so far made on the subsoil improvement of subsurface drainage systems for wet paddy fields (those were located in the Gum-Ho area in Kyung Buk province) which had poor permeability and a high water table. In general, a drainage problem is an excess of water on the ground surface which can effect the productivity and bearing capacity of the soil. With drain pipe systems, (According to their depths and spacing) it may be possible to correct that problem. The experimentation consisted of three test plots, two of which included drain pipe systems with varing depths and width spacing of the pipes. The third plot (C) was an ordinary plot being exempt of a drain pipe system. In detail, the depth of plot A was 80 cm, and the width spacings began at 2. Om and increased by 2. Om up to 10. 0m. The depth of plot B was 60cm and the width spacing was the same as plot A. These tests were performed to research specific details; such as crop yeild, bearing capacity of the soil, the amount of underdrainage, surface cracks, root distribution, the water table level, the consumptive water depth and the soil moisture content. The test period lasted three years, from 1977 thru 1979. The results obtained were as follows: 1. During the test period, the weather conditions for the area tested were in accordance with the annual average for that area. Furthermore the precipitation factor during the spring cultivation season, the intermediate drainage period and the harvest drainage period was of optimum conditions for controling surface cracks, because of less precipitation than evaporation. 2. The difference in the level of the ground water table in plots A and B was hardly noticable, but the difference in the test plots and the ord. plot was greatly noticable. The test plots (A, B) were 30 to 40cm lower than the ordinary plot. On the whole, the ground water table of the ord. plot always stayed at a level of 15-20cm beneath the surface of the soil, the ground water table of the test plot A showed The difference in the depth of the pipe lower than the test plot B, while the test plots showed a remarkable descending effect. 3. The soil temperature in plot A was slightly core than in plot B with a difference of 0. 47$^{\circ}$C, but plot A was 1. 6$^{\circ}$C higher than the ord. plot during the flooding period, but after drainage the temperature difference climed to 2. 0$^{\circ}$C. 4. During the 3rd test year, the values of the cracks were recorded with the values of 59cm in plot A, 42cm in plot B and 15cm in the ordinary plot. Plots A and B had increased 2.5 times the value of the first year while the ordinary plot had remained the same. 5. The root weight of the rice was measured at a value of 77.2 gr. for plot A, 73.5 gr. for plot B and 65.3 gr. for the ord. plot. Therefore, the root growths in plots A and B were much more energetic than in the ord. plot. 6. The consumptive water depth measured during the 3rd year resulted in the values of 26. 0mm per day for plot A, and 24.9 mm per day for plot B, respectively. Therefore, both plot A and plot B maintained the optimum consumptive water depths, but the ordinary plot only obtained the value of 12.3 mm per day, which clearly showed less than the optimum consumptive water depth which is 20 to 30 mm/day. 7. The soil moisture content is in direct relationship to the ground water level. During drainage, test plot A decreased in its ground water level much more rapidly than the other two plots. Therefore, plot A had a much less soil moisture content. But this decreased water level could be directly effected by the weather conditions. 8. The relationship between the bearing capacity and the soil moisture content were directly inversely proportional. It can be assumed that the occurence of soil creaks is limited by the soil moisture content. Therefore, the greater the progress of the surface creaks resulted in a greater bearing capacity. So, tast plot A with a greater amount of surface cracks than the other test plots resulted in a greater bearing capacity. But, the bearing capacity at the harvest season could be effected by the drainage during the intermediate drainage period and by the weather conditions. 9. Comparing the production of the test plots to the ord. plot; there was an increased value of 840kg for plot A, 755kg for plot B and 695kg for the ord. plot in the rough rice. Therefore, plot A had an increase of 20% over the ordinary plot. The possibility of producing double crops was investigated. The effects on barley production in the test plots showed a value of 367kg per 10 acres, which substantiated the possibility of double crops because that value showed an increased value over the average yearly yield for those uplands. 10. So as a result, it can be recommended that by including a drain pipe system with the optimum conditions of an (80cm centimeter) depth and a (l0m) spacing will have a definite positive effect on the over all production capacity and quality of wetpaddy fields.

• 한국산학기술학회논문지
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• 제19권11호
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• pp.319-325
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• 2018

3D 프린팅 (적층 공정) 기술은 소재와 공정기술의 지속적인 연구개발을 토대로 초기 모형 제작 활용으로부터 현재는 산업현장의 양산형 부품 제작까지 그 쓰임새가 확대되고 있다. 3D 프린팅의 대표적인 고분자 소재로서 고강도 엔지니어링 플라스틱의 하나인 polyamide (폴리아미드) 계열의 소재는 제품의 경량화 및 내구성의 장점으로 자동차용 부품 제작에 주로 활용된다. 이번 연구에서는 적층기법 중 제작품의 물성이 우수한 선택적 레이저 소결 기법 (Selective Laser Sintering)을 적용하여 polyamide 12 (PA12) 및 글라스 비드 (glass bead) 보강 PA12 소재 2가지를 대상으로 시편을 제작하고 온도에 따른 굴곡특성을 분석하였다. 작업 플랫폼 기준으로 $0^{\circ}$, $45^{\circ}$, $90^{\circ}$ 방향으로 각 시편을 제작 후, $-25^{\circ}C$, $25^{\circ}C$, $60^{\circ}C$ 등 3개 시험온도 환경에서 굴곡 테스트를 진행하였다. 그 결과로, PA12 는 $-25^{\circ}C$ 에서 $90^{\circ}$ 제작 방향이, $25^{\circ}C$ 와 $60^{\circ}C$에서는 $0^{\circ}$ 제작방향이 최대 굴곡강도를 가졌다. 글라스비드 보강 PA12는 제작방향이 $0^{\circ}$인 겨우 모든 시험온도에서 최대 굴곡강도 값을 보였다. 두 소재의 서로 다른 굴곡강도 변화 경향은 굴곡시험시 발생하는 응력 종류에 따라 적층 레이어 평면 방향에 의한 영향이 서로 다르기 때문으로 판단된다.

• Fisheries and Aquatic Sciences
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• 제10권1호
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• pp.1-7
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• 2007

The induction of cellular and humoral immunity and cytokine gene expression by synthetic CpG oligodexoynucleotides (CpG-ODNs) has not been investigated systematically in olive flounder Paralichthys olivaceus in vivo. We optimized the proper concentration of CpG-ODNs using an in vitro assay for the superoxide anion $(O_2^-)$. CpG-ODNs induced $O_2^-$ and nitric oxide (NO) production, lysozyme activity, and the proinflammatory cytokine gene expression of $IL-1{\beta}$ and $TNF-{\alpha}$ in olive flounder significantly in vivo, whereas non-CpG-ODNs did not produce these effects or produced them to a lesser extent. This implied that CpG-ODNs could stimulate cellular and humoral immunity and cytokine gene expression in olive flounder. This is the first evidence of NO production and the first study on the mRNA expression of the proinflammatory cytokine genes $IL-1{\beta}$ and $TNF-{\alpha}$ in olive flounder in response to CpG-ODNs. Comparison of the variation in NO production and lysozyme activity to that of other studies led us to postulate that a group-specific difference exists in the immune responses of olive flounder against CpG-ODNs. Furthermore, the detailed immunostimulatory spectrum of CpG-ODNs in olive flounder could be a useful index with which to analyze the effect of CpG-ODNs against the challenge test prior to field applications.

• 한국지반환경공학회 논문집
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• 제22권2호
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• pp.5-13
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• 2021

본 연구에서는 최근 강소재의 발전에 의해 고강도 강관의 제작이 실용화됨에 따라 고강도 강관 쏘일네일링 공법의 안정성 및 적용성에 대한 평가를 수행하였다. 쏘일네일링 공법에서 보강재로 사용되고 있는 이형철근을 동일직경의 고강도 강관으로 대체할 때의 보강재의 거동특성과 보강력 증대효과를 규명하고 안정성을 확인하기 위하여 현장시험시공을 실시하였다. 인장시험결과 측정변형률 값이 이론식에서 산정된 변형률보다 작은 값을 보이므로 이형철근을 사용한 쏘일네일링 공법과 유사한 거동을 한다고 볼 수 있다. 변위측정 결과, 고강도 강관의 변위가 이형철근 보다 큰 값을 보이는 것은 강관 내부그라우팅 영향과 단면적 감소에 따른 영향인 것으로 판단된다. 쏘일네일링 공법에 고강도 강관을 사용하는 경우 부재성능 및 경량화를 통하여 안정성 및 시공성 향상에 따른 현장적용성이 양호한 것으로 판단된다.

• 유기물자원화
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• 제25권4호
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• pp.23-29
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• 2017

본 연구는 조사료 생산 분야에서 화학비료를 사용하는 관행농법에서 벗어나 유기재배 기술개발을 위하여 관행재배와 유기재배의 수량성, 사료가치 등을 비교 조사하였다. 시험은 전남 강진군 작천면 소재 축산연구소의 논에서 수행하였다. 유기질 비료로는 질소성분이 4.0% 함유된 유박비료를 이용하였으며, 시험구 편성은 대조구(Con)와 대조구 질소 함량 기준으로 환산하여 유박비료 100% 처리구(T1), 유박비료 150% 처리구(T2), 유박비료200% 처리구(T3)로 구성 하였다. 시험품종은 수수${\times}$수단그라스 교잡종(SX17)을 5월 25일에 ha당 40kg을 휴립세조파(조간 50cm)로 파종하였다. 수확기 처리구별 초장은 대조구 317cm, T1 252cm, T2 269cm, T3 293cm으로 대조구가 가장 우수하였고, 시비 처리구에 따른 시험구에서는 시비량의 증가에 따라 증가하였고, 건초량은 대조구 11.386kg/ha, T1 6,015kg/ha, T2 6,799kg/ha, T3 7,627kg/ha으로 초장의 생육과 동일한 경향을 보였다. 조단백질은 대조구 7.0%, T1 5.7%, T2 6.3%, T3 5.1%로 시험 처리구에서는 T2에서 가장 높았다. 이와 같은 결과로 유박비료를 대조구 시비량 질소 함량 대비 150% 시비에서 사료가치는 유의적 차이를 보이지 않았으나, 초장과 건초량이 증가가 이루어졌으므로 150% 기준으로 시비하는 것이 적합할 것으로 판단된다.

• Journal of Advanced Marine Engineering and Technology
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• 제38권3호
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• pp.246-252
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• 2014

본논문은 150마력급 선내형 소형 워터제트 추진시스템 개발에 대한 연구이다. 워터제트는 흡입부, 임펠러, 디퓨저(공기확산기), 후진부와 메인 샤프트로 구성되어 있다. 워터제트의 구성품은 사형 주조후 정밀가공을 거쳐 개발하였다. 워터제트 추진기관의 개발은 각각의 부품에 대한 설계-제작-검사의 과정을 거쳐 최종 완성하였으며, 육상 시험 풀에서는 선체의 이동 없이 워터제트의 펌프 특성을 확인한 결과, 최대 37m/s의 유속과 0.29m3/s의 유량을 배출할 수 있는 성능을 확보하였다. 본 연구에서 개발된 워터제트 추진장치를 설치한 21ft 시험선을 사용하여 실증 연구를 수행하였다. 그 결과, 국내 연안에서 시험시 선체무게와 엔진등 기타 부수적인 무게가 대략 1.2ton 가량 이였으며 이 상태에서 엔진회전수 3,700rpm에서 최대시속 45km/h의 운항속도를 기록하였다.