• 한국산학기술학회논문지
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• 제19권11호
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• pp.688-694
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• 2018

이액형 액상 실리콘 혼합비율은 혼합된 액상 실리콘 원재료를 통해 완성된 제품이 갖추어야하는 고유의 물리적 특성에 더 부합되며 제품 품질에 중요한 요소이기 때문에 주재료와 부재료의 균일한 비율제어는 필요하다. 본 연구에서는 주재료와 부재료 각각의 원재료 이송유량을 확인할 수 있는 디지털 유량계와 유량제어시스템, 압력을 일정하게 유지함과 동시에 원재료 이송을 위한 펌핑 시스템으로 구성 되도록 혼합 비율 제어시스템을 설계 하였다. 또한 시스템과의 유기적인 연동과 혼합비율 제어를 위한 프로그램을 개발 하였다. 개발된 시스템의 검증을 위해 펌핑을 통한 실제 계량된 원재료의 중량과 유량계의 측정값을 비교 하였으며, 혼합 비율 향상 알고리즘의 적용 유무에 따른 테스트 시편을 제작하여 혼합된 재료의 물리적 특성을 측정하였다. 테스트 결과 알고리즘을 적용한 시편의 경우 경도는 46~47 범위, 인장 강도는 9.3MPa~9.5MPa 범위로 기준값에 가까운 측정값을 얻을 수 있었다. 이 결과들은 이액형 실리콘의 혼합 비율을 ${\pm}0.5%$이내의 오차 범위에서 제어됨을 알 수 있었다.

• Journal of Biosystems Engineering
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• 제20권3호
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• pp.288-298
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• 1995

In greenhouse vegetable, the automatic control in cultivating environment has been projected as a national business ; especially a countermeasure against the settlement of UR negotiation. Because it makes possible to manage a large greenhouse with family-hands and to expect the betterment of quality and the increasement of harvest in crops. In the course of carrying the workout, however, there are many problems with the overall control system with computers as well as the individual systems for environment control because of hardware and software problems : especially the shortage of data for development of the system is most serious. Among the many problems for development of the automatic control system, the automations of irrigation, liquefied fertilizer and chemical solution, mixing and ventilation, etc and the development of the general automatic controller system for environment control in greenhouse are studied, which requires a lot of tabors. The results are summarized as follows ; 1. In moisture control by the soil moisture meter, the error was shown 10 % in the beginning irrigation point and 19 % in the stop irrigation point. 2. The supply of liquefied fertilizers with the irrigation system was excellent by setting the operating time and the mixing ratio. 3. The developed chemical spraying system was operated well, but not perfect in nozzle positions. 4. The cucumber was cultivated properly with the trickle irrigation system. 5. The developed controller for the automatic control system in greenhouse was remarkable in the part of hardware, but more researches are needed in the part of software.

• 한국건축시공학회지
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• 제1권2호
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• pp.174-178
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• 2001

This study was performed to control the thermal crack of the mat footing slab in the multi-purposed buildings. In this study, we executed the mixing design of concrete to satisfy the workability and the quality according to the site conditions. And, we evaluated quantitatively about the possibility of thermal crack by using hydration heat analysis system. Finally, we proposed the optimal mixing conditions, curing methods and curing period which all factors are considered. As a result, the optimal mixing conditions were : W/B 41%, unit binder 375kgf/$\textrm{m}^3$, FA replacement ratio 20%. Lowest thermal stress was 22.0kgf/$\textrm{cm}^2$ and at that time thermal crack index was over 1.5, when the coefficient of thermal conductivity was lowest among the curing conditions. And, the total curing time was estimated at 6.7 days according to curing steps.

• 한국농공학회논문집
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• 제65권1호
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• pp.61-72
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• 2023

The increase in the rearing intensity of pigs has caused deterioration in the pig house's internal environment such as temperature, humidity, ammonia gas, and so on. Traditionally, the widely used method to control the internal environment was through the manipulation of the ventilation system. However, the conventional ventilation system had a limitation to control the internal environment, prevent livestock disease, save energy, and reduce odor emission. To overcome this problem, the air-recirculated ventilation system was suggested. This system has a semi-closed loop ventilation type. For designing this system, it was essential to evaluate the ventilation rates considering the pressure loss of ducts. Therefore, in this study, pressure loss calculation and experiment were conducted for the quantitative ventilation design of a semi-closed loop system. The results of the experiment showed that the inlet through which external air flows should always be opened. In addition, it was also found that for the optimum design of the semi-closed loop ventilation system, it was appropriate to install a damper or a backflow prevention device rather than a ventilation fan.

• 동력기계공학회지
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• 제19권1호
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• pp.56-63
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• 2015

In this study, the exhaust characteristics of the diesel engine for the change of the mixing ratio of biodiesel fuel were quantitatively analyzed by using the numerical analysis method. As the fuel used in the experiment, the diesel and biodiesel(waste oil, soybean oil), the mixed fuel BD2(Diesel only), BD3, BD5, BD20, BD50 and BD100 were used. The injection pressure($p_{inj}$) was set to 400bar, 600bar, 800bar, 1000bar and 1200bar as the experimental variable. Also the concept of the standard deviation, Pearson's correlation coefficient and Spearman rank-order correlation coefficient based on the statistics was introduced in order to analyze the exhaust characteristics of the quantitative NOx and Soot according to the injection pressure and the mixing ratio variation of biodiesel blending fuel. It is considered that as a result of studies, for the waste oil, NOx and Soot can be simultaneously reduced through control of the mixing ratio at the regions of $p_{inj}=400bar$ and $p_{inj}=600bar$, and the Soot can be reduced without affecting on the emission of NOx at more than $p_{inj}=800bar$. For the soybean oil, NOx and Soot can be simultaneously reduced at $p_{inj}=400bar$ and the Soot can be reduced without affecting on the emission of NOx at $p_{inj}=600bar$.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2006년도 춘계 학술발표회 논문집
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• pp.372-382
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• 2006

The DCM(Deep Cement Mixing) Method was introduced domestically in 1985 and has been applied widely to improve stability, increase bearing capacity and reduce settlement of the structure. It has been only performed by the combined equipment to improve the soft ground in coastal areas. But it has qualify-control problems such as interference of waves and improving depth, etc. Therefore DCM Barge of specialist equipment, named by Dong Ji Ho, was equipped with three mixing shafts with four rod and installed GPS system In itself, had been developed in 2005 for the purpose of solving the above problems. This paper represents about Dong Ji Ho's qualify-control system as well as it's first domestic application to in-situ trial test and the original design of the Ulsan breakwater site.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 봄 학술발표회 논문집
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• pp.533-538
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• 2001

This study was peformed to control the thermal crack of the mat footing slab in the multi-purposed buildings. In this study, we executed the mixing design of concrete to satisfy the workability and the quality according to the site conditions. And, we evaluated quantitatively about the possibility of thermal crack by using hydration heat analysis system. Finally, we proposed the optimal mixing conditions, curing methods and curing period which all factors are considered. As a results, the optimal mixing conditions were : W/B 41%, unit binder 375kg/$cm^{2}$, FA replacement ratio 20%. Lowest thermal stress was 22.0kgf/$cm^{2}$ and at that time thermal crack index was over 1.5, when the coefficient of thermal conductivity was lowest among the curing conditions. And, the total curing time was estimated at 6.7 days according to curing steps.

• Transactions on Electrical and Electronic Materials
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• 제10권1호
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• pp.1-4
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• 2009

Dry etching characteristics of indium tin oxide films and etch selectivities over photoresist films were investigated using $Cl_2/HBr$ inductively coupled plasma. From a Langmuir probe diagnostic system, it was observed that while the plasma temperature was kept nearly constant in spite of the change of the HBr mixing ratio, the positive ion density decreases rapidly with increasing the mixing ratio. On the other hand, a quadrupole mass spectrometer showed that the neutral HBr and Br species increased. The etching mechanism in the $HBr/Cl_2$ plasma was analyzed.

• 대한기계학회논문집B
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• 제39권8호
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• pp.645-651
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• 2015

본 논문은 중앙구동 이젝터의 유량비에 미치는 설계변수의 영향에 대한 연구를 목적으로 한다. 중앙구동 이젝터의 설계변수는 구동노즐 출구 단면적 및 거리비, 디퓨저 출구 단면적비로 설정하였다. 실험장치는 가변노즐 이젝터, 전동 모터-펌프, 구동유체 저장수조, 제어판넬 그리고 고속 카메라 시스템으로 구성하였다. 유량비는 실험변수에 따라 측정되는 유입 공기량과 구동유체인 물의 유량을 이용하여 도출하였다. 유량비는 구동노즐 거리비와 혼합관 길이비가 커지면 증가하는 반면에, 구동노즐 면적비와 디퓨저 출구 면적비가 커지면 감소하였다.

• Journal of the Korean Wood Science and Technology
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• 제21권2호
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• pp.57-65
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• 1993

The aim of this research was to manufacture sludge-particle board using paper sludge with wood particle and to investigate physical and mechanical properties of various sludge-particle boards, fabricated with ratios of sludge to particle of 10 to 90, 20 to 80, 30 to 70, 40 to 60 and 50 to 50(oven dry weight based). Sludge-particle boards were manufactured by urea-formaldehyde resin, 0.8 target specific gravity, and 10mm thickness. It was possible to manufacture sludge-particle board as the same processing in the present particleboard manufacturing system. This sludge-particle board have different properties as composition ratios of sludge and particle. And sludge-particle board made from 10 percent to 20 percent of sludge mixing ratio have similar mechanical properties compared with control particleboard. Especially, the sludge-particle board made from 10 percent to 40 percent mixing ratios of sludge have superior to control particleboard in internal bond, screw withdrawal holding strength and modulus of elasticity. In the case of dimensional stability, water absorption was increased and thickness swelling was decreased as increased with sludge mixing proportion. The sludge-particle board made of different mixing ratios of our laboratory design was able to concluded that there is possibility of partial substitution of wood particle materials.