This study aims to explore the appropriate water pressure control of water supply pipeline to reduce water losses of water supply network in Jinan-gun. The current water pressure status of each 5 blocks and the impact of optimized water pressure on improving revenue water rate were investigated. In order to obtain the flow rate and water pressure data of each small block, a smart hub is set in the pressure reducing valve chamber at the inlet of the small block, and a smart water pressure meter is installed in the fire hydrant and the faucet of the customer. For the pressure reducing valves installed for water pressure management system of each block, the diameter calculation standard and type of the pressure reducing valve are determined, and the application reasons are put forward. The analysis results of water pressure management for each small block in Jinan-gun show that the pressure control equipment and water pressure management need to be improved in four small blocks. The water flow rate in Jinan-eup and Sangjeon-myeon increases from 57.2% to 87.6% when the water pressure control is completed.

Recently, considerable attention has been given to nickel-based superalloys used in additive manufacturing. However, additive manufacturing is limited by a slow build rate in obtaining optimal densities. In this study, optimal volumetric energy density (VED) was calculated using optimal process parameters of IN718 provided by additive manufacturing of laser powder-bed fusion. The laser power and scan speed were controlled using the same ratio to maintain the optimal VED and achieve a fast build rate. Cube samples were manufactured using seven process parameters, including an optimal process parameter. Analysis was conducted based on changes in density and melt-pool morphology. At a low laser power and scan speed, the energy applied to the powder bed was proportional to and not . At a high laser power and scan speed, a curved track was formed due to Plateau-Rayleigh instability. However, a wide melt-pool shape and continuous track were formed, which did not significantly affect the density. We were able to verify the validity of the VED formula and succeeded in achieving a 75% higher build rate than that of the optimal parameter, with a slight decrease in density and hardness.

본 연구에서는 2020년 6월에서 9월까지 4개월 동안 우리나라 하천 중 금강 백제보에 주로 서식하는 말조개, 펄조개와 대칭이를 채집하여 서식처 특성을 살펴보았고, 이들의 여과율을 실내 실험을 통하여 측정하여 검량선을 산출하였다. 백제보에서 채집된 말조개, 펄조개, 대칭이는 24시간 동안 평균 154.84 μg L-1의 Chl-a를 제거하였으며, 이는 실내 수조 (2 L) 내의 식물플랑크톤 C. vulgaris (초기 Chl-a=168.34 μg L-1)를 약 24시간 만에 제거할 수 있는 것으로 나타났다. 따라서, 본 연구에서 사용한 말조개, 펄조개, 대칭이가 연평균 4 만 마리가 서식할 경우 (Lee et al., 2020), 6월 한달 동안 예상되는 Chl-a의 저감 효과는 10.55%으로 예측되고 7월의 경우 34.88%, 8월의 경우 20.14%, 9월의 경우 46.21%로 평균 27.94%의 저감 효과를 예상할 수 있다. 이러한 결과는 간접적으로 이매패류가 서식지에서 효과적으로 Chl-a를 제거 할 수 있을 가능성을 제시한다. 실제로 이매패류를 통하여 수생태계의 조류 제어능력을 평가하기 위해서는 이매패류뿐만 아니라 식물플랑크톤, 수생식물, 저서생물, 퇴적물, 유속 등의 작용들을 종합적으로 고려해야 하지만 본 연구에서는 이매패류의 여과율과 이에 따른 Chl-a에 저감율에 기반하여 수생 태계 조류 제어능력을 산정하였다. 본 연구 결과들은 차후 다양한 요인과 관점에서의 통합된 연구에 기초적인 정보를 제공할 것으로 사료된다.

Background/Aim: Endoscopic retrograde cholangiopancreatography (ERCP) training requires varying degrees of staff assistance regarding operation of the fluoroscopy machine via a foot pedal. Efficiency is important to acquire during this training due to radiation risks. In this study, we evaluate the effect of controlling endoscopy and fluoroscopy unit on duct cannulation rates (CRs) and total fluoroscopy time (FT) for fellows in training. Methods: 204 patients undergoing ERCP were randomized to one of two groups: 1) “Endoscopist Driven” group in which the endoscopist controlled the foot pedal for fluoroscopy, and 2) “Assistant Driven” group in which attending or fellow controlled the foot pedal while the other team member controlled the endoscope. Various measures including selective duct CR and total FT were recorded. Results: There was no significant difference in mean procedure duration between the two groups (32 minutes vs. 33 minutes, p=0.70). There was also no statistically significant difference in CR (83.7% vs. 77.4%, p=0.25) or FT (3.27 minutes vs. 3.54 minutes, p=0.48). Conclusions: ERCP is a technically challenging procedure which requires extensive supervision. This study demonstrates that CR and FT are not affected by who controls the fluoroscopy.

In this study, three kinds of metal chills such as SS400, AC4CH and brass, with different thicknesses of 40 ~ 80 mm, were applied for low pressure casting of Al-Si alloy to control cooling rate. The microstructural characteristics with increasing cooling rate were represented using factors including D1, D2, size of primary α phases and shape factor and size of eutectic Si. The tensile properties were investigated and additionally analyzed based on the microstructural characteristics. As the cooling rate increased, D1, D2, and sizes of primary α phases and eutectic Si apparently decreased and the shape factor of eutectic Si increased to over 0.8. The ultimate tensile strength (UTS) and yield strength (YS) increased with decreasing D1, D2, and size of primary α phases, while elongation increased with decreasing size of eutectic Si and concurrently increasing shape factor of eutectic Si. This indicated that the primary α phases and eutectic Si in Al-Si alloy were refined with increasing cooling rate, resulting in improvement of UTS and YS without sacrificing elongation. After the tensile test, preferential deformation of primary α phases was observed in the Al-Si alloy produced at higher cooling rates of more than 0.1 K/s.

This study suggested a new real-time traffic signal operation algorithm using combined data of travel time and occupancy rate. This study applied the travel time data to traffic signal control system, and developed the signal operation algorithm based on saturation degree that was calculated using the travel time data. This algorithm calculates a queue length using a delay model, and converts the queue length to the saturation degree. Moreover, it calculates signal timing variables using this combined saturation degree. This study conducted a microscopic simulation for effectiveness evaluation. We checked that the average intersection delay decreased by up to 27 percent. Moreover, we checked that this signal operation algorithm could respond to a traffic condition of oversaturation and loop detector error effectively and usefully. In korea, sectional traffic detection systems are being installed in various ITS projects, such as Advanced Transportation Management System(ATMS) and Urban Transportation Information System(UTIS). This study has important significance in the sense that it is new methodology to accept the sectional detection system in traffic signal control system.

Ventilation devices and room air cleaners can be used to remove indoor contaminants from indoor air. Generally, room air cleaners are rated according to clean air delivery rate (CADR). However, a similar metric for ventilation has not been used to be compared with CADR of room air cleaner. The CADRs and cost-effectiveness metrics (CADR/kw) of ventilation devices and room air cleaners were newly defined and theoretically compared for a child care center. The results indicate that the CADRs of room air cleaner were greater than that of ventilation. A higher collection efficiency for the particles guaranteed a higher CADR for ventilation. Ventilation filter had a performance that exceeds MERV11 should be used to effectively control the indoor particle concentration. The stand alone type air cleaner was found to have the best performance in the cost-effectiveness. The reason for this is that the effective air cleaning ratio of the stand alone type air cleaner is higher than that of the others and the power consumption of the stand alone type air cleaner is lowest.

In the present work, bismuth nanopowders with various particle size distributions were synthesized by controlling argon (Ar) gas flow rate and chamber pressure of a gas condensation (GC) apparatus. From the analyses of transmission electron microscopy (TEM) images and nitrogen gas adsorption results, it was found that as Ar gas flow rate increased, the specific surface area of bismuth increased and the average particles size decreased. On the other hand, as the chamber pressure increased, the specific surface area of bismuth decreased and the average particles size increased. The optimum gas flow rate and chamber pressure for the maximized electrochemical active surface area were determined to be 8 L/min and 50 torr, respectively. The bismuth nanopowders synthesized at the above condition exhibit 13.47 of specific surface area and 45.6 nm of average particles diameter.

Because sampling interval for data collection tends to be short compared with the overall processing time, in chemical process, instrumental process related tanks or furnace collected data have a significant autocorrelation. Insufficient control technique

본 논문은 Lyapunov 함수의 목표 변화율을 이용한 슬라이딩 모드 제어 기법을 제안한다. 슬라이딩 모드 제어는 구조물이 안정적인 거동을 하는 슬라이딩 표면을 정의하고 정의된 슬라이딩 표면에서 구조물이 거동하도록 만드는 제어기법으로 선형제어와 뱅뱅제어 등의 다망한 제어기 설계가 가능하다. 그러나, 기존 연구에서 선 형제어의 경우 Lyapunov 함수의 변화율이 음수라는 조건만 만족하도록 제어기 설계를 수행하여 제어기의 성능을 충분히 활용하지 못한다. 또한 제어기의 성능을 극대화하기 위해 사용하는 뱅뱅제어의 경우, 불필요하게 큰 제어력이 발생하는 문제점을 가지고 있다. 제안된 제어기법은 설계자에 의해 설정된 Lyapunov 함수의 목표 변화율을 달성함으로써 제어기의 성능을 효율적으로 활용할 수 있다. 수치해석결과, 제안된 제어기법은 기존의 선형제어보다 큰 최대응답감소의 효과를 가지며, 기존의 뱅뱅제어보다 적은 제어력을 가지고도 동등한 제어효과를 보인다.

현재(現在) 우리나라에서 재배(栽培)되고 있는 국화(菊花) 8품종(品種)을 공시(供試)하여 국화(菊花)잎선충에 대(對)한 저항성조사(抵抗性調査), 피해엽율(被害葉率)과 강우(降雨)와의 관계(關係), 그리고 관수방법(灌水方法)이 피해엽율(被害葉率)에 미치는 영향(影響)을 조사(調査)하고 몇가지 살충제의 방제효과(防除效果)에 관(關)하여 실험(實驗)한 결과(結果), l. 국화(菊花)잎선충(Aphelenchoides ritzemabosi)에 대(對)한 국화품종(菊花品種)의 저항성(抵抗性) 검정(檢定)에서 Shuhonothikara는 11.7%, Sagakiku는 14.5%로서 저항성(抵抗性)을 나타내었고 Sinrokusiogio, Dangonanako, Sintoa 등(等)은 50% 이상(以上)의 피해엽율(被害葉率)로 감수성(感受性)을 나타냈으며 Gold wave, Tenju 등(等)은 24~26%로 중간정도(中間程度)를 나타냈다. 2. 피해엽율(被害葉率)과 엽면적(葉面積), 엽후(葉厚), 기공수(氣孔數), 기공(氣孔)의 크기 및 모즙장(毛葺長) 등(等)과는 상관(相關)이 없었고 모즙수(毛葺數)와는 정(正)의 상관(相關)을 나타냈다. 3. 관수방법(灌水方法)에 따른 피해엽율(被害葉率)은 P. E. film에 의(依)한 강우(降雨)를 차단(遮斷)하고 지면관수(地面灌水)한 구(區)에서 9.4%로 가장 낮았으며, 자연상태(自然狀態)에서 지면관수(地面灌水)한 구(區)가 50%로 다음이었고 자연상태(自然狀態)에서 Spray한 구(區)가 62.4%로 가장 높게 나타났다. 4. 피해엽율(被害葉率)과 강우(降雨)와의 관계(關係)는 강우량(降雨量)보다는 강우일수(降雨日數)가 밀접(密接)한 관계(關係)를 내타내었다. 5. 살선충제의 토양처리(土壤處理)에 의(依)한 방제효과(防除效果)는 무처리구(無處理區)에 비(比)해 현저한 방제효과(防除效果)를 보여 주었으며 약제별(藥劑別)로는 Temik이 평균피해엽율(平均被害葉率)이 5%로 가장 낮게 나타났으며 무처리(無處理)나 타약제(他藥劑)에 비(比)하여 현저한 유의차(有意差)를 나타내었고 Carbofuran, Otran, Mocap 등(等) 약제간(藥劑間)에는 유의성(有意性)은 인정(認定)되지 않았으나 무처리(無處理)에 비(比)하여는 고도(高度)의 유의차(有意差)를 나타내었다.

수단그라스계 잡종(雜種)인 Pioneer988의 수량(收量)과 잡초억제(雜草抑制) 및 조단백질함량(粗蛋白質含量)에 대한 파종량(播種量)과 제초제(除草劑)의 효과(效果)를 구명(究明)하기 위하여 파종량은 ha당(當) 25kg와 50kg으로 처리하였으며 제초처리(除草處理)는 인력제초(人力除草), alachlor 처리, simazine 처리 및 alachlor와 simazine을 복합(複合)처리하였고 대조구로 잡초(雜草) 효임구(效任區)를 두었다. 수량(收量

The advanced oxidation treatment using persulfate and zero-valent iron (ZVI) has been evaluated as a very effective technology for remediation of soil and groundwater contamination. However, the high rate of the initial reaction of persulfate with ZVI causes over-consumption of an injected persulfate, and the excessively generated active species show a low transfer rate to the target pollutant. In this study, ZVI was modified using selenium with very low reactivity in the water environment with the aim of controlling the persulfate activation rate by controlling the reactivity of ZVI. Selenium-modified ZVI (Se/ZVI) was confirmed to have a selenium coating on the surface through SEM/EDS analysis, and low reductive reactivity to trichlroethylene (TCE) was observed. As a result of inducing the persulfate activation using the synthesized Se/ZVI, the persulfated consumption rate was greatly reduced, and the decomposition rate of the model contaminant, anisole, was also reduced in proportion. However, the final decomposition efficiency was rather increased, which seems to be the result of preventing persulfate over-consumption. This is because the transfer efficiency of the active species (SO4-∙) of persulfate to the target contaminant has been improved. Selenium on the surface of Se/ZVI was not significantly dissolved even under oxidation conditions by persulfate, and most of it was present in the form of Se/ZVI. It was confirmed that the persulfate activation rate could be controlled by controlling the reactivity of ZVI, which could greatly contribute to the improvement of the persulfate oxidation efficiency.

마이크로웨이브 균일분산 시스템을 이용하여 자연생태계에 영향을 주지 않고 잡초종자발아를 제어함으로써 토양 및 수질 오염에 영향을 주지 않는 새로운 개념의 제초제 대안을 제시하고자 한다. 명아주(Chenopodium album var. centrorubrum), 쇠비름(Portulaca oleracea)과 한련초(Eclipta prostrata)의 식물에 대한 마이크로웨이브의 토양 함수량별, 깊이별 조사한 결과 균일 분사된 마이크로웨이브를 이용한 잡초 종자의 발아율 측정에서 마이크로웨이브는 토양 함수량에 따른 종자의 발아 조절에는 토양 함수량 20%, 30%에서 최고의 효율이 나타났으며, 토양의 깊이에는 별 영향을 받지 않는 것으로 나타났다. 마이크로웨이브 조사시간은 30초 이상 조사시 잡초 종자의 발아를 억제 할 수 있는 것으로 나타나 적절한 토양 함수량(20~30%) 및 이에 따르는 30초 이상 조사한 마이크로웨이브의 균일분산 시스템을 통해 제초제를 대신하여 잡초종자발아를 조절할 수 있을 것으로 생각된다.

This study was investigate to evaluate the phosphate uptake rate of green algae in relation to diurnal rhythm and algae control method. The phosphate uptake rates of Chlorella vulgaris and Ankistrodesmus convolutus increased in light period and decreased in dark period. On the contrary, those of Chlamydomonas sp. showed a peak in the late dark period. The differences among species in phosphate uptake in relation to diurnal rhythm were due to the severe competition among species and seemed to alleviate the competition for nutrient supplies. The compound of CellCaSi, Ca and Fe showed the effective removal of the phosphorus. The extracts from rice and barley straw exhibited a significant effect on the growth inhibition of Microcystis aeruginosa.