• Journal of Biosystems Engineering
• /
• 제9권2호
• /
• pp.1-7
• /
• 1984

The engines mounted on power-tillers are used as power source in various kinds of works such as plowing, harrowing, transporting, spraying, water pumping and threshing, etc. But the engines have not been used effectively from a standpoint of fuel consumption because of lack of proper power transmission system and lack of understanding of fuel consumption characteristics of the engines. Therefore, this study was attempted to establish proper power transmission system between the power-tiller engines and various implements. In order to accomplish the above objective, firstly, power requirement and pulley sizes for various implements, which are driven by the power-tiller engines, were investigated to find out whether the power transmission system is proper. Secondly, partload variable engine-speed test was conducted for 3 different sizes of diesel engines to measure to specific fuel consumption. Thirdly, the present power transmission systems were analyzed in terms of specific fuel consumption, and proper power transmission systems were suggested for various implements. The results of this study are summarized as follows: 1. Power requirement for each fixed-type implement of power-tiller varied from 1.5 ps to 11 ps according to its type and operating conditions, but generally in the range of 2.5 ps to 7 ps. 2. Each power tiller and implement were equipped with only one size of pully with few exeptions. With the present power transmission systems, the engines can't be utilized effectively in terms of fuel economy. The pulley size of engine or implement should be diversified to provide the optimum engine speed for different implements. 3. For a diesel eninge with the rated power output of 6 ps, the optimum engine speed to minimize specific fuel consumption was 2200 rpm for the power reguirement in the range of 6 ps or more, 1700 rpm in the range of 4 to 6 ps, and 1200 rpm in the range of 4 ps or less. 4. For a diesel engine with the rated power output of 8 ps, the optimum engine speed was 2200 rpm for the power requirement in the range of 7 ps or more, 1700 rpm in the range of 4.8 to 7 ps, and 1200 rpm in the range of 4.8 ps or less. 5. For a diesel engine with the rated power output of 10 ps, the optimum engine speed was 2200 rpm for the power requirement in the range of 8.4 ps or more, 1700 rpm in the range of 5.4 ps to 8.4 ps, and 1200 rpm in thr range of 5.4 ps or less. 6. Provided the existing implements are dirven by 8 ps diesel engines, the optimum size of engine pulley should be larger than 120mm for the works of requiring less than 4 ps and 90-110mm for the works requiring 4.5-6.5 ps in order to minimize fuel consumption.

• 농업과학연구
• /
• 제29권2호
• /
• pp.67-77
• /
• 2002

본 연구에서는 로타리 경운작업시 흙 부착이 가장 많이 되고 소요동력에 큰 영향을 미치는 로타리 커버 내측에 흙이 부착되는 것을 방지하여 경운 소요동력의 절감에 기여할 수 있는 로타리 커버를 개발하는데 목적이 있으며, 그 구체적인 연구결과는 다음과 같다. 1. 본 연구의 수행을 위하여 트랙터의 로타리 경운 소요동력을 측정하고자 트랙터 PTO축과 로타리 동력 입력축을 연결하는 PTO 동력 전달축을 이용하여 로타리 경운 소요동력 측정장치를 설계, 제작하였다. 2. 로타리에 장착한 흙부착 방지장치의 재질로는 스테인리스 스틸, 고무, PE 등을 사용하였다. 흙부착 방지장치 장착 로타리를 이용하여 로타리 경운시험을 통한 경운 소요동력을 측정한 결과 평균 일반 로타리는 52.18ps, 스테인리스 스틸재질 장착 로타리는 52.44ps, 고무재질 장착 로타리는 49.01ps, 그리고 PE재질 장착 로타리는 46.34ps의 소요동력을 나타냈다. 3. 흙부착 방지장치 장착 로타리를 이용하여 로타리 경운시험 후 부착된 흙의 양을 조사한 결과 평균 일반 로타리는 5.6kg, 스테인리스 스틸재질 장착 로타리는 5.7kg, 고무재질 장착 로타리는 3.1kg, 그리고 PE재질 장착 로타리는 2.7kg으로 나타났다. 4. 실험결과를 토대로 유의수준 5%의 모평균 차에 의한 검정으로 분석해본 결과 스테인리스 스틸재질의 경우 흙부착 방지효과가 없는 것으로 나타났으며, 고무와 PE재질의 경우에 방지 효과가 있는 것으로 나타났다. 그 중 PE 재질이 소요동력과 흙부착 방지에 각각 11%, 52%의 감소효과가 있어 소요동력 감소 및 흙부착 방지 효과가 탁월한 것으로 나타났다.

• Journal of Biosystems Engineering
• /
• 제6권1호
• /
• pp.60-72
• /
• 1981

This study was carried out to find out the effects of the sheaf size of paddy harvested by the binders on the threshing performance, load characteristics and power requirement of an auto-feed thresher. The results of the study are summarized as follows: 1. The seperating performance of the thresher appeared to be satisfactory for all the sheaf sizes although the amount of rubbishes and empty grains slightly increased with the sheaf size of paddy. 2. There was no significant difference in grain output quality of the thresher among the three sheaf sizes. However, the amount of grains left unthreshed increased with the sheaf size. In the case of the largest sheaf size with the feed rate of 780kg/h, it exceeded the limit set by the national inspection regulations. 3. The position of the feed-chain rail gave a significant effect on the power requirement of the thresher. At the feed rate of 780kg/h, the net power required to convey sheafs through the feed chain was in the range of 0.37 to 0.50 PS for the middle and lowest position of feed-chain rail, and there was no significant difference among the sheaf sizes. At the highest position, however, it appeared that the smallest sheaf required more power than the others. The net power requirements at this position were 1.03, 0.59. 0.65 PS for the smallest, medium and largest sheafs respectively. 4. The torques of both the thresher and the engine shaft increased with the feed rate and were not affected by the sheaf size for the lower two feed rates of 520 and 780kg/h. At the highest feed rate of 1,040 kg/h, however, they were affected by the sheaf size. In this case, the medium sheaf size gave lower values than the others. 5. The variations in the thresher and the engine torque increased with the feed rate and were not affected by the sheaf size for the feed rate of 520kg/h. At the feed rate of 780kg/h, however, they increased with sheaf size. And at the feed rate of 1,040 kg/h, the torque variations increased greatly for all the sheaf sizes due to an over-load operating condition. 6. It appeared that the average and maximum power requirements of the thresher increased with the feed rate. But, there was no significant difference in power requirement among the sheaf sizes for the lower two feed rates. 7. The threshing efficiency of the thresher was in the range of 214-249 kg/ps.h with the feed rates of 520 and 780 kg/h, and it was not affected by both the sheaf size and the feed rate. At the feed rate of 1,040 kg/h, however, it decreased to as low as 171-174 kg/ps.h because of a sudden increase in power requirement. 8. The average power requirements of the engine were slightly higher than those of the thresher due to the slippage of flat belt between the thresher and engine. It appeared that power transmission from the engine to the thresher was maintained properly since slippages were moderately low with the range of 2.78 to 6.51% throughout the tests. 9. The specific fuel consumption of the engine (diesel 8PS) decreased as the feed rate increased. However, there was no significant reduction in specific fuel consumption as the feed rate increased above 780 kg/h.

• Neonatal Medicine
• /
• 제16권2호
• /
• pp.101-109
• /
• 2009

Pulmonary surfactant (PS) therapy in premature infants has a remarkable impact on improving survival and outcomes in neonatal respiratory distress syndrome (RDS). Early PS therapy involves instillation of PS upon delivery of very premature infants or if there is evidence of RDS, such as an increased requirement of oxygen 2 hours after birth, especially in infants <30 weeks gestation. Early PS treatment in very premature infants results in a significant reduction in the severity of RDS, mortality, and incidence of pneumothorax, pulmonary interstitial emphysema, and bronchopulmonary dysplasia in comparison with late PS treatment. According to European and American consensus guidelines on the management of neonatal RDS, early PS instillation should be considered for infants <30 weeks gestation, infants with a birth weight <1,250 g, or if the mother has not received antepartum corticosteroids. We suggest that the Korean health insurance policy on RDS be modified so that PS can be used for better clinical outcomes of very premature infants.

• 항공우주기술
• /
• 제6권2호
• /
• pp.126-133
• /
• 2007

유공압 설비 설계에 있어서 중요한 요소인 유공압 구성품의 압력손실계수를 측정하기 위한 시험 설비의 설계, 제작 그리고 일련의 시험 내용 및 PS(Pyrostarter, 고체추진제 가스발생기) 연소시험 결과와의 비교 분석 내용을 정리한다. 최종적으로 blow-down 시스템을 이용하여 간단한 시험 설비를 구축하였으며 PS에 사용되는 필터들의 압력손실계수를 측정하였다. 시험 설비를 통해 PS의 CQSF 압력손실계수 K를 획득하였으며, PS 연소시험 결과와의 비교를 통해 2% 내외의 높은 신뢰도의 압력 손실 예측이 가능한 것으로 나타났다. 한편 PS 필터의 K와 PS 연소압과의 관계를 유도하여 PS 연소시험 결과와 일치함을 보였으며, 향후 PS 개발에서 필터의 K를 활용하여 PS 추진제의 연소속도를 향상시킬 수 있을 것으로 기대된다.

• Journal of Nutrition and Health
• /
• 제57권2호
• /
• pp.261-274
• /
• 2024

Purpose: Recently, high-protein diets have become highly popular, and the market for protein products has steadily increased in Korea together with the development of various types of such products. However, there is limited information on the consumption of protein supplements (PS) or protein-fortified foods (PF). Thus, this study aimed to evaluate the use of PS/PF among young adults in Jeju. Methods: A total of 350 adults (140 men and 210 women) aged 19-39 years voluntarily participated in this study from June 2022 to May 2023. PS/PF use was measured using a questionnaire. Dietary intake was assessed using a 24-hour dietary recall. Results: Approximately 31.4% of the participants (n = 110) had consumed PS/PF for more than 2 weeks during the past year and 71.8% of them (n = 79) were still consuming these products (PS/PF consumers). The PS/PF consumers tended to be male and physically active (p < 0.05 for all). The most frequent reason for PS/PF use was muscle gain (59.5%), followed by protein supplementation (19.0%) and body fat loss (13.9%), and the most frequent type of PS/PF consumed was powders (70.6%), followed by drinks (17.7%) and bars (8.8%). The PS/PF consumers tended to consume a high-protein low-carbohydrate diet compared to the non-consumers. The prevalence of consuming dietary protein less than the estimated average requirement (EAR) was significantly lower in PS/PF consumers (13.9%) compared to non-consumers (25.4%; p = 0.0316). Conclusion: These findings indicate that the necessity of protein supplementation should be determined based on the current dietary protein intake and individual requirements. The study also provides the basic information for establishing guidelines for appropriate protein intake.

• 대한원격탐사학회:학술대회논문집
• /
• 대한원격탐사학회 2008년도 International Symposium on Remote Sensing
• /
• pp.375-377
• /
• 2008

The KOMPSAT2 Terminal Polar Station was recently installed at near North Pole, Tromso, and Toulouse. The K2PS consists of one receiving station and two processing sites. The receiving station has been installed at SvalSat ($N78^{\circ}$, $E15^{\circ}$ ), and the two receiving sites have been installed at KSAT (Kongsberg Satellite Service AS), Tromso, Norway ($N69^{\circ}$ ,$E18^{\circ}$ ) and SISA, Toulouse, France ($N43^{\circ}$ ,$E1^{\circ}$ ). The products ofK2PS system can be classified to two categories: Level 1R product and Level 1G product. The Level 1R product is radiometric corrected product with RPC (Rational Polynomial Coefficients) and the Level 1G product is geometric corrected product with POD (Precise Orbit Data) and PAD (Precise Attitude Data) data based on Level 1R product. To meet a SISA (Spot Image SA)'s requirement, K2PS system has high performance product producing capability. This paper describes overall K2PS systems' production generation flow and the mass production test result of K2PS systems.

• 한국멀티미디어학회논문지
• /
• 제2권3호
• /
• pp.329-338
• /
• 1999

본 논문에서는 무선 ATM의 MAC 프로토콜로 DTDD!PS(Dynamic Time Division Duplex using PolV S Select scheme)을 제안한다 DTDD!PS 프로토콜의 기본 개념은 기지국과 단말로 구성된 무선 ATM 라디오 셀올 큐잉 시스템으로 고려하는 것이다. 기지국에 있는 MAC 제어기는 각 단말의 QoS(Quality of Service)를 만족시키기 위해 각 단말의 순간적인 대역요구의 수용에 초점을 둔다. 이를 위해 기지국에서는 각 단말로부터 동적 매개변수를 받아 이것을 이용하여 기지국에서는 각 단말들의 접속 상태를 통제하고 슬롯 단위로 대역의 동적인 할당을 한다. 이러한 방법으로 유선 ATM 보다 낮은 전송률을 갖는 무선 ATM에서 실시간 서비스의 Q QoS를 만족시킬 수 있게된다. DTDD/PS 프로토콜의 성능을 평가하기 위해서 시율레이션을 수행하였다. 그 결과 전송률이 251이bps인 시스템에서 음성 단말과 데이터 단말이 공폰된 환경에 대한 시률레이션올 수행한 결과 음성 단말의 증가에 따라 데이터 트래픽의 지연이 급격히 증가하는것을 볼 수 있었다. 그러나, 데이터 단말의 부하가 증가하더라도 음성단말에 우선 순위를 주고 있는 상황에서 동시통화 음성단말의 수는 크게 변화가 없다. 따라서 멀티미디어 트래픽과 같은 다양한 QoS를 갖는 트래픽이 공존하는 상황에서 DTDD/PS 프로토콜이 효과적으로 적용될 것올 예상할 수 있다.

• Journal of Biosystems Engineering
• /
• 제9권2호
• /
• pp.27-36
• /
• 1984

This study was carried out to investigate the effects of the tilling depth, tilling travel speed and soil shear stress on the tilling load characteristics and power requirement for rotary tillers. The results obtained from the study are summarized as follows. 1. The average and maximum PTO torque increased as the tilling depth, tilling pitch and soil shear stress increased. A multiple linear regression equation to estimate the average PTO torque in terms of the above parameters was developed. 2. The ratios of maximum PTO torque to the average torque were in the range of 1.17 to 1.65 for the various tilling conditions tested. The variation in PTO torque increased greatly as the tilling pitch and soil shear stress increased, but decreased as the tilling depth increased. 3. Power requirement for the PTO shaft increased with the tilling depth, travel speed and soil shear stress, but decreased slightly as the tilling pitch increased. A multiple linear regression equation to estimate power requirement for the PTO shaft in terms of the above parameters was developed. 4. The specific power requirement for the rotary tiller was in the range of $0.008-0.015ps/cm^2$ for the various tilling conditons tested. The specific tilling capacity decreased as the tilling depth and soil shear stress increased, but increased with the tilling pitch. A multiple linear regression equation to estimate the specific tilling capacity in terms of the above parameters was developed.

• Journal of Biosystems Engineering
• /
• 제28권4호
• /
• pp.295-304
• /
• 2003

In this study, a rotary equipped with devices for preventing alien substance from being wound and for preventing soil adherence were developed and their performances are evaluated in the field. The former device was effective in the paddy field with low moisture content, but power requirement of rotary tilling was increased in the field with high moisture content. In the field test of rotaries equipped with device to prevent the power requirements were measured to be 52.18, 52.44, 49.01 and 46.34 PS for general, stainless steel, rubber and PE rotaries, and the quantities of the soil adhered to rotaries, on the average, were to be 5.6, 5.7, 3.1 and 2.7 kg for general, stainless steel, rubber and PE rotaries, respectively. The PE rotary cover reduced the power requirement and soil adherence by 11 and 52%, respectively.