Hydraulic cylinders are hydraulic system parts widely used in various industries such as construction machinery, machine tools, robots, automobiles, and automation systems. The maximum capacity of vane pumps used in machine tools is 70bar, but the actual operating pressure is less than 50bar. The allowable pressure of a commercial hydraulic cylinder is 140 - 210 bar, so it is heavy and uneconomical because it uses thick and strong materials. In this paper, we intend to develop a small and lightweight hydraulic cylinder suitable for the allowable pressure of 50bar or less so that it can be used in the hydraulic system field. In order to develop a compact hydraulic cylinder, flow analysis, and structural analysis were conducted under piston forward and backward conditions. The analyzed flow rate value was calculated to be suitable for the operation of the hydraulic cylinder. As a result of comparing the stress calculated under the forward/backward condition of the piston with the yield stress of the material, the safety factor was calculated to be more than 2.5.

본 연구는 간호대학생의 대면 및 비대면 임상실습스트레스와 스트레스 대처가 임상수행능력에 미치는 영향을 알아보고 각 요인 간 영향을 파악함으로써 간호대학생이 임상실습스트레스에 효율적으로 대처하고 임상수행능력을 증진할 수 있는 임상실습교육 전략의 근거를 제시하고자 시행되었다. 연구대상자 는 서울과 충청권 소재 간호대학생으로, 2021년 6월 10일부터 7월 10일까지 총 201부의 자료를 수집하였 다. 통계프로그램 SPSS 21.0을 이용하여 Pearson’s correlation coefficients로 대면 및 비대면 임상실습스트 레스, 스트레스 대처, 임상수행능력 간의 상관관계를, 위계적 다중회귀분석을 사용하여 임상수행능력에 미 치는 요인을 분석하였다. 연구결과, 1단계에서 간호대학생의 성적, 전공만족도, 대면실습만족도가 임상수행 능력의 19.4%를 설명하였고, 2단계에서는 스트레스 대처를 추가하여 19.6%의 설명력이 증가되어 총 39.0%의 변량을 설명할 수 있었다. 따라서 간호대학생의 임상수행능력 향상을 위해서는 임상실습스트레스 에 대한 원만한 스트레스 대처가 중요하며, 본 연구는 간호대학생의 스트레스 대처를 위한 상담 및 교육프 로그램을 개발하는 기초자료를 제공할 것이다.

본 연구에서는 인공광 시설에서 광원을 달리하여 생산된 방풍나물의 항산화 및 항염 효과를 평가하였고 노지 재배 된 방풍나물과 그 생리활성을 비교하였다. DPPH 및 ABTS 라디칼 소거 활성 및 총 폴리페놀은 노지에서 재배 된 방풍나물이 인공광 시설에서 재배된 방풍나물보다 높은 항산화 활성을 나타내었고, 인공광에서 재배된 방풍나물 중 에서는 BW 광원으로 재배된 방풍나물이 농도 의존적으로 높은 항산화 효과를 보였다. XO 저해 활성은 BW 재배된 방풍나물이 노지 재배 방풍나물보다 우수한 효과를 나타내었다. SOD와 CAT 결과는 BW 및 노지 재배된 방풍나물 모두 무처리 대조군에 비해 농도 의존적인 활성을 보였다. BW 및 노지 재배된 방풍나물은 방풍나물을 처리하지 않은 무처리 대조군에 비해 TNF-α 와 IL-6 사이토카인을 농도 의존적으로 유의하게 감소시켰다. 따라서 인공광 재배 된 방풍나물은 대체적으로 노지보다 낮을 수 있지만 항산화 및 항염 효과를 보였고. 앞으로 인공광에서 재배된 작물의 다양한 기능성 소재로서의 연구에 도움이 될 것으로 기대된다.

In the manufacturing industry, sparks occur during operation due to collisions of metals, and strong sparks and arcs are generated even during welding works. X-rays are generated when high-speed electrons from outside collide with electrons in a metal. Thus, the objective of this study proposes the risk of sparks and arcs that can generate X-rays. We developed the spark generator using the electrostatic principle and constructed the arc generating device using the high voltage. The X-rays are measured when sparks and arcs are continuously generated between the anode metal target and the cathode metal. The measured X-rays were found to be harmful to humans when exposed for a long period. Therefore, workers exposed to workplaces with frequent sparks and arcs need to protect themselves.

The reliability of the lifting system has to be ensured so that heavy cargo is handled safely during loading and unloading. Therefore, the accelerated life test was performed on the lifting bow shackle, which is highly affected by the main failure mode, among the components of the lifting system. Besides, an efficient inspection method was suggested for the preventive maintenance of the bow shackles. The acceleration index and acceleration coefficient of the bow shackles were calculated by using the life data of them. The guaranteed life data of the bow shackle can be used to predict the useful life in industries related to lifting work.

PURPOSES : Recently, there has been an increase in the use of discrete randomly distributed fiber materials for reinforcing pavement foundations. However, very limited study has been made on this from the perspective of pavement engineering. Therefore, this study evaluates the performance of soil-geofibers used in pavement foundations as well as the effects of stress dependency with various mixtures. METHODS: To estimate the behavior of soil-geofiber mixtures under traffic loadings, laboratory resilient modulus data for the mechanical characteristics of geofiber mixtures were used, and they were adopted to evaluate the structural response and analyze the stress dependency through 2-D finite element analysis. As the host materials, poorly graded and uniformly graded sand were selected, and each soil was mixed with three different types of fiber, namely monofilament, fibrillated, and tape. RESULTS: The stress dependent response on resilient modulus and Poisson’s ratio were mainly considered by conducting linear and nonlinear elastic analyses on various geofiber mixtures. As a result, it was found that the response and yield function of geofiber mixed layers in pavements were affected considerably depending on the gradation of the soils and the confinement conditions. A small change was found when the particle size was homogenized. CONCLUSIONS : From this, it can be concluded that the finite element model with stress dependency is suitable for estimating the performance on geofiber mixtures. It is also noted that all the responses of geofiber mixtures were relatively sensitive to the gradation of host soils. This indicates that the effects of the nonlinearity and stress-dependency of geofiber mixtures under repetitive loadings could be substantial.

유럽에서 양송이 야외발효에 많이 사용하던 윈드로우터너를 우리나라 실정에 맞게 밀짚대신 볏짚을 사용할 수 있도록 개량 개발하였다. 관행 굴삭기작업과 비교하여 조사한 결과는 다음과 같다. 교반작업 성능은 81 m3 /hr으로 굴삭기 28.6 m3 /hr보다 2.8배 높았으며, 재배사 한 동(균상면적 165 m2 )당 1회 배지교반시간이 46분으로 관행보다 노력을 66% 절감할 수 있는 것으로 분석되었다. 또한 야외발효 말기 배지더미의 온도분포 조사 결과 배지더미 중앙 아래부분의 온도가 관행보다 5℃ 이상 높아 호기발효에 유리한 것으로 나타났으며, 부숙도를 추정할 수 있는 회분조사결과 30.9±1.1%로 나타나 관행 28.4±1.6%보다 부숙정도도 높게 나타났다. 버섯의 농가 재배결과 수확량이 시작기의 경우 관행 대조구 대비 22.9% 증수되는 것으로 나타났다.

본 연구는 병재배 느타리버섯 정밀재배를 위한 최적 생육모델 개발을 위하여 느타리 ‘수한1호’ 농가를 대상으로 스마트팜 기술을 적용하여 생육환경을 분석한 결과를 보고하고자 한다. 실험 농가의 균상면적은 88 m², 균상형 태는 2열 5단, 냉동기는 5마력, 단열은 샌드위치 판넬 100T, 가습기는 초음파 가습기 2대, 난방은 12KW를 사용 하였고, 5,000병을 입병하여 재배하고 있었다. 느타리버섯 재배농가에서 생육환경 데이터를 수집하기 위하여 설치한 환경센서부로부터 버섯의 생육에 직접적으로 영향을 미치는 온도, 습도, 이산화탄소 농도, 조도 등을 수집 분석하였다. 수집한 온도자료를 분석한 결과, 균 긁기한 후 입상 시 온도는 22°C에서 시작하여 버섯이 발생되어 병을 뒤집기를 할때까지 거의 25°C를 유지하고 자실체가 자라서 수확기에 가까워지면 13°C에서 15°C를 유지하면서 버섯을 수확하였다. 습도자료를 분석한 결과, 습도는 입상에서 생육전 과정동안 거의 100%를 유지하였다. 이산화탄소농도 자료를 분석한 결과, 입상후 3일까지는 서서히 증가하였으나, 그 이후 급격히 증가하여 거의 2,600 ppm 까지 증가하였고, 6일차부터는 환기를 통해 단계적으로 농도를 낮추어 수확기에는 1,000 ppm을 유지하였다. 조도 자료를 분석한 결과, 느타리버섯 입상후 초기에는 거의 빛을 주지 않았고 3~4일차에 17 lux의 빛을 조사하였으며, 그 이 후 주기적으로 115~120 lux의 빛을 조사하면서 생육을 진행하였다. 농가에 재배하고 있는 ‘수한1호’의 자실체 특성은 갓 직경은 30.9 mm, 갓 두께는 4.5 mm이며, 대 두께는 11.0 mm, 대 길이는 76.0mm였다. 대 경도는 0.8 g/mm, 갓 경도는 2.8 g/mm였고, 대와 갓의 L값은 79.9와 52.3이였다. 자실체 수량은 160.2 g/850 ml였고, 개체중은 12.8 g/ 10 unit였다.

To compare functional Chinese cabbage(‘Amtak’ baechu; F1 hybrid cultivar between Brassica rapa and B. perkinensis, AB) with general Chinese cabbage (‘Chunkwang’ baechu; general spring cultivar, CB), two kinds of kimchi(ABK and CBK) prepared with AB and CB cultivar were fermented at 10°C for 10 days. Their fermentative characteristics and anti-proliferative activities against mouse carcinoma cell lines were investigated. General kimchi(CBK) showed mature pH on the 6th day of fermentation, whereas functional kimchi(ABK) reached pH on the 9th day. CBK also exhibited acidity of mature stage on the 6th day, but ABK reached mature acidity on the 9th day. Although ABK and CBK were salted in the same condition, ABK had lower salinity than CBK, throughout the fermentation time. The highest total bacterial and lactic bacterial counts of CBK showed on the 8th day of fermentation, but ABK showed the highest total bacterial and lactic bacterial counts on the 10th day. The texture of ABK was harder than CBK for fermentation time. This seems to be corrleated with the slower fermentation rate of ABK. ABK showed significantly higher anti-proliferative activity (54.6% cell viability of control) in B16BL6 at 1,000 μg/mL. ABK was also higher in anti-proliferative activity than CBK throughout the fermentation time. However, there was no significant difference in the anti-proliferative activity of ABK between the fermentation times. In conclusion, fermentation of ABK showed a better texture, due to the slow fermentation rate and more anti-proliferative activity against mouse carcinoma cell line than those of CBK.

A self-propelled turner was developed to produce mushroom compost at low costs and high efficiency, and the uniformity of compost produced by an excavator, compost mixer, and self-propelled turner was compared. The material of the compost was mixed with rice straw and chicken manure at a dry weight ratio of 3:1. After the final turning, internal temperature distribution, water content of the compost pile, ash ratio, and uniformity of the compost pile were examined. After the compost was completed, the water content was 69.9 ± 0.54%, 72.1 ± 0.15%, and 74.5 ± 0.82%, respectively. The length of rice straw was 47.5 ± 15.4 cm, 24.9 ± 10.1 cm, and 31.0 ± 10.6 cm, respectively. The ash content in the dry weight of each compost was 25.0 ± 6.2%, 33.6 ± 4.2%, and 28.2 ± 1.1%, respectively. The deviation in the length of rice straw was affected by the linear velocity of the spinner in the compost mixer and the self-propelled turner, which were 21.5 m/sec and 9 m/sec, respectively. As a result, the most uniform mushroom compost was produced by the self-propelled turner.

This study was carried out to develop the technology to manage the growth of mushrooms, which were cultivated based on long-term information obtained from quantified data. In this study, hardware that monitored and controlled the growth environment of the mushroom cultivation house was developed. An algorithm was also developed to grow mushrooms automatically. Environmental management for the growth of mushrooms was carried out using cultivation sites, computers, and smart phones. To manage the environment of the mushroom cultivation house, the environmental management data from farmers cultivating the highest quality mushrooms in Korea were collected and a growth management database was created. On the basis of the database value, the management environment for the test cultivar (hukthali) was controlled at 0.5 °C with 3–7% relative humidity and 10% carbon dioxide concentration. As a result, it was possible to produce mushrooms that were almost similar to those cultivated in farms with the best available technology.

The oyster mushroom cultivation house typically has multiple layers of growing shelves that cause the disturbance of air circulation inside the mushroom house. Due to this instability in the internal environment, growth distinction occurs according to the area of the growing shelves. It is known that minimal air circulation around the mushroom cap facilitates the metabolism of mushrooms and improves their quality. For the purpose of this study, a CFD analysis FLUENT R16 has been carried out to improve the internal environment uniformity of the oyster mushroom cultivation house. It is found that installing a section of the working passage towards the ceiling is to maintain the internal environment uniformity of the oyster mushroom cultivation house. When all the environment control equipment – including a unit cooler, an inlet fan, an outlet fan, an air circulation fan, and a humidifier – were operated simultaneously, the reported Root Mean Square (RMS) valuation the growing shelves were as follows: velocity 23.86%, temperature 6.08%, and humidity 2.72%. However, when only a unit cooler and an air circulation fan operated, improved RMS values on the growing shelves were reported as follows: velocity 23.54%, temperature 0.51%, and humidity 0.41%. Therefore, in order to maintain the internal environment uniformity of the mushroom cultivation house, it is essential to reduce the overall operating time of the inlet fan, outlet fan, and humidifier, while simultaneously appropriately manage the internal environment by using a unit cooler and an air circulation fan.

This study was conducted to evaluate the possibility of expanding the usage of whole crop silage from beef cattle and dairy cow to hogs and chickens. For this purpose, a crushing device was developed to crush whole crop silage. The crushed silage was sealed, and analyzed for its feed value. The silage varieties used for the experiment included Saessal barley and Geumgang wheat. Whole crop barley and wheat were crushed in the crushing system as a whole without separating stems, leaves, grains, etc.. When the crushed whole crop silages (CWCS) were analyzed, full grain, grains above 10 mm in size, grains 5～10 mm in size, and grains below 5 mm in size accounted for, 20%, 4%, 27%, and 49 %, respectively. In order to facilitate the fermentation of CWCS, inoculated some fermenter into each CWCS sample (barley or wheat). As control, another set of sample was not inoculated. Crude protein (CP), ether extract (EE), crude fiber (CF), neutral detergent fiber (NDF), acid detergent fiber (ADF), lignin, cellulose content, total digestible nutrient (TDN), and relative feed value (RFV) of fermenter-inoculated Saessal barley were 2.45 %, 1.61%, 8.95%, 16.94%, 9.52%, 1.01%, 8.51%, 81.38%, and 447.5%, respectively. The CP, EE, CF, NDF, ADF, lignin, cellulose content, TDN, and RFV in the other sample of Saessal barley without inoculation of fermenter were 2.57%, 1.62%, 9.61%, 18.25%, 10.13%, 1.10%, 9.04%, 80.90%, and 412.9%, respectively. The CP, EE, CF, NDF, ADF, lignin, cellulose content, TDN, and RFV of fermenter-inoculated Geumgang wheat sample were 2.43%, 1.27%, 10.99%, 19.49%, 11.23%, 1.46%, 9.77%, 80.03%, and 382.6%, respectively. The CP, EE, CF, NDF, ADF, lignin, cellulose content, TDN, RFV of the other set sample of Geumgang wheat sample without the inoculation of fermenter were 2.28%, 1.44%, 10.08%, 18.02%, 10.44%, 1.26%, 9.18%, 80.65%, and 416.9%, respectively. The TDN and RFV content in the fermenter-inoculated Saessal barley were 81.38% and 447.5%, respectively, while the one in the fermenter-inoculated Geumgang wheat were 80.03% and 382.6% respectively. When the feed value of whole crop barley and wheat silage without crushing process was compared to the feed value of whole crop barley and wheat silage made from crushing system, the latter appeared to be higher than the former. This could be due to the process of sealing the crushed silage which might have minimized air content between samples and shortened the golden period of fermentation. In conclusion, these results indicate that a crushing process might be needed to facilitate fermentation and improve the quality of silage when making whole crop silage.

국내 버섯재배 농가는 약 4,160호, 재배면적은 764ha, 생산량은 208,207M/T(‘14)으로 농업적․산업적으로 매우 중요한 위치를 차지하고 있으며, 느타리버섯의 경우 약 2,200농가에서 76,389M/T(’14)을 생산하여 전체 버섯생 산량의 37%를 차지하고 있다. 최근 ICT를 이용한 대형화 자동화 재배공정 개발이 활발히 이루어지고 있으나 표준적인 관리시스템이 없어 안정적 재배를 위한 저비용 고효율 재배관리 프로그램 개발이 필요하고, 특히 귀 농 귀촌을 원하는 초보농가를 비롯하여 안정적인 대규모 재배를 원하는 기존 농가를 위한 버섯 생체정보를 기 반으로 한 정밀 환경관리 시스템 구축이 필요다. 본 시험은 병재배 느타리버섯의 정밀재배를 위한 기초자료를 제공하기 위하여 농가별 환경시스템 및 자실체의 특성을 조사한 결과이다. 국내 느타리버섯 재배농가에서 사 용하고 있는 온도 및 CO2 센스는 주로 이레테크, 소하테크, 원예용 센스 등의 제품이 사용하고 있었으며, 내부 의 냉방, 환기, 공기순환 등은 농가마다 재배사의 특성에 맞게 다양한 방법을 사용하고 있었고 표준화된 환경 제어 시스템은 없었다. 병재배 느타리버섯은 버섯품종에 관계없이 균긁기후 8일안에 모든 수확이 완료 되었으 며, 수한 및 흑타리 품종 모두 균긁기 6일 후 갓의 직경이 평균 7.3~15.4mm에서 7일에는 평균 21.5~32.7mm로 하루만에 급속히 자라 수확단계에 도달하였다. 수한의 수확시 갓의 직경은 평균 29.6mm, 대의 길이는 35.2mm 였고, 갓의 명도값은 27.3이였다. 최근에 많이 재배되고 있는 흑타리의 수확시 갓의 직경은 27.1~33.8mm, 대의 길이는 41.5~46.1mm였으며, 갓의 명도값은 35.4~41.1이였다. 앞으로 병재배 느타리의 정밀재배관리를 위해서 는 보다 많은 농가의 버섯 생육특성과과 환경과 생육과의 상호 관련성 분석 등에 대한 많은 자료가 축적되어 야 할 것으로 판단된다.