• 소성∙가공
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• 제8권1호
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• pp.65-77
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• 1999

In recent years, the quality requirements from the customers of hot rolled steel strip have been steadily increasing in diversity and strictness. To meet these quality requirements as well as to improve productivity, steel mills have been doing their efforts for developing high performance Automatic Gauge Control (AGC) system. However, it is very time consuming and also needs a lot of money to develop the new technologies of AGC in actual mill. So, there has been a demand for developing the Dynamic Hot Rolling Simulator since late 80's. It is a kind of software packages and can analyze the dynamic behaviors of hot finishing rolling process without laborious experiments in actual mill. It can also be used as a designing tool of Automatic Gauge Controller. In this work, the Dynamic Hot Rolling Simulator which is applicable to 6 sands hot strip mill rolling was developed. The MATLAB with SIMLINK was used as a software developer for making the main part of simulator because it is very powerful tool for modeling, integrating, controller design, and simulation. In this paper, the structures and the mathematical models of the simulator were briefly described and the results of simulation on the transient phenomena of hot rolling process with actual mill data were also presented.

• 전기학회논문지
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• 제63권9호
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• pp.1300-1305
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• 2014

In this paper, we suggest an optimization method which can save about 5[%] of the cost though the optimizing of configuration and capacity for the facility. To achieve this goal, we compared the design data of the power, motor and drive system with the actual operation data of the plate mill plant in K-Steelworks. Therefore we measured the actual loading data by facilities considering the operating conditions of the plate mill plant in K-Steelworks, after that analyzed these data. In addition, we review the optimal capacity for transformer, switchgear and drive, and also reconfigured the electrical room and power single line diagram through the validation of motor data by equipment and the confirmation of process data considering the load characteristics. Consequently, the optimization method of capacity for the facilities shall have effectiveness in building new plate mill plant to further reduce costs at future.

• 전력전자학회논문지
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• 제8권3호
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• pp.239-246
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• 2003

BLDC 전동기는 높은 효율과 출력밀도로 인하여, 현재 산업응용 분야에 널리 적용되고 있으며, 특히 고성능 제어 특성과 저소음 운전특성으로 인하여 가정용 전자제품의 활용도가 높아지고 있다. 본 논문에서는 제한적인 설계조건에서 요구성능을 만족하는 트레드 밀 구동용 BLDC 전동기를 설계하고, 이에 적합한 제어기를 제작하였다. 전동기설계에서 제한된 고정자 구조에 대하여, 제작의 용이성과 경제성을 고려하여 CAD와 FEM 해석을 통하여 영구자석의 형상을 설계하였다. 설계된 제어기는 트레드 밀의 안정된 구동과 성능을 위하여 운전자의 무게와 회전속도에 따라 학습된 제어기의 이득이 사용되도록 제작되었다. 제시된 트레드 밀 구동용 BLDCM과 제어기는 실험을 통하여 성능을 확인하였다.

• 한국생산제조학회지
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• 제25권6호
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• pp.426-433
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• 2016

This paper investigates the effects of operating conditions of an air classifier mill (ACM) on the particle sizes of PVC and rice hull. Based on the Box-Behnken matrix, the pulverization experiments were performed considering three operating factors: the air flow rate, the classifier speed and the mill speed. The response surface methodology was applied to identify the effects of the operating factors on the particle size. Results show that the particle sizes are governed by the linear variations of the operating factors. As less air is supplied and the mill rotates more slowly, the powder of both PVC and rice hull becomes finer. Furthermore, the classifier speed has a significant effect on the PVC powder but almost no effect on the rice hull powder. Thus, it is found that strong interactions exist between the material characteristics of a particle and the operating conditions of the ACM.

• 대한산업공학회지
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• 제24권4호
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• pp.649-660
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• 1998

Steel making in Mini Mill consists of three major processing stages: molten steel making in an electric arc fuenace, slab casting in a continuous caster, and hot rolling in a finishing mill. Each processing stage has its own lot grouping criterion. However, these criteria in three stages are conflicting with each other. Therefore, delveloping on efficient lot grouping algorithm to enhance the overall productivity of the Mini Mill is an extremely difficult task. The algorithm proposed in this paper is divided into three steps hierarchically: change grouping, cast grouping, and roll grouping. An efficient charge grouping heuristic is developed by exploiting the characteristics of the orders, the processing constraints and the requirements for the downstream stages. In order to maximaize the productivity of the continuous casters, each cast must contain as many charges as possible. Based on the constraint satisfaction problem technique, an efficient cast grouping heuristic is developed. Each roll consists of two casts satisfying the constraints for rolling. The roll grouping problem is formulated as a weighted non-bipartite matching problem, and an optimal roll grouping algorithm is developed. The proposed algorithm is programmed with C language and tested on a SUN Workstation with real data obtained from the H steel works. Through the computational experiment, the algorithm is verified to yield quite satisfactory solutions within a few minutes.

• Journal of Mechanical Science and Technology
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• 제18권7호
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• pp.1062-1073
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• 2004

We describe a looper controller design for a hot strip finishing mill in steel plants. The main function of the looper system is to balance the mass flow of the strip by accumulating material in the middle of the stands. Another function is to control the strip tension which influences the width of the strip. To ensure strip quality, it is very important to control the tension of the hot strip finishing mill. However, because there is a mutual interaction between the looper angle and the strip tension, it is difficult to control the looper system. Previous researches examined only the operation of a single stand. But it is not sufficient to examine the operation and effect of whole stands because the operation is wholly interdependent. In this paper, we present a full model of the hot strip finishing mill in order to more effectively control strip tension. We propose several control methods for the full-stand hot strip finishing mill, denoted as conventional PI, PI with cross gain, and coefficient diagram method (CDM) PID control. In the real plants, there are some problems by using higher order controllers such as LQ, LQG and H$\_$$\infty$/. By comparison, the PID controller is very simple and easy to apply to all real plants. To that end, we present our findings on PID controls and their potential use in the hot strip finishing mill.

• World Technopolis Review
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• 제5권1호
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• pp.30-46
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• 2016

This paper is intended as an opening of a dialog on how to apply platform thinking in the development of innovation environments. It will briefly describe a new STP (Science and Technology Park) concept called 3GSP (Third Generation Science Park), which is gaining momentum in Finland. The paper explains the fundamental changes that are currently taking place in the global innovation environment and explains why platform thinking is becoming an essential element in ecosystem development. The theoretical background and classifications of platforms are described and the benefits to be gained from STP perspective are highlighted. The paper emphasizes especially the role of so called 'competence platforms' and explains the main characteristics of a fully working competence platform. The role of competence platforms in understanding serendipity and as a fundamental factor in building the team is also highlighted. The paper analyses from STP perspective several practical examples, where platform thinking supports the emergence of new innovation environments, including Urban Mill (Finland) and Meetberlage (Netherlands). The requirements for comprehensive competence platform services are presented and their potential to support community building and therefore ecosystem development is illustrated. This analysis will provide STP practitioners with new models for applying platform thinking and will help to establish co-creation, open innovation and serendipity management practices. The case studies presented will help STP management teams to evaluate the benefits of competence platforms in different contexts.

• 한국환경농학회지
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• 제23권1호
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• pp.22-27
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• 2004

제지공장의 슬러지를 활성오니슬러지와 집수조슬러지로 나누어 C/N율, 메탄발효폐액 첨가 그리고 몇몇 첨가제를 처리하고 발생한 혐기발효가스 중 메탄함량을 측정하여 각각의 처리효과를 조사해 보았다. 1. 활성오니 제지슬러지를 이용한 메탄발효의 최적 C/N율은 60으로 이전의 다른 재료들과는 다른 경향이었다. 2. 혐기발효 폐액의 첨가로 메탄함량 40% 도달 시간은 약 2일정도 앞당겼지만, 10일간의 총 메탄발생량은 1/8 수준으로 적었다. 3. 첨가제중 sodium sulfide와 ethylacetate의 처리효과는 발효폐액 첨가구에서 뚜렷하였고, 무첨가구에서도 sodium sulfide는 1.3배의 메탄생성 증가에 기여하였다. 4. 황화수소가 제거된 제지슬러지에서는 메탄이 전혀 생성되지 않았고, sodium sulfide가 첨가된 처리구에서는 메탄생성이 증가되었기에 제지슬러지 메탄발효에서 황은 필수적이라고 할 수 있다.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2006년도 PAN PACIFIC CONFERENCE vol.1
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• pp.105-110
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• 2006

In order to utilize coal fly ash (hereafter : coal ash ) discharged from coal boiler as a material for civil engineering usage such as snow melter or soil improver, we have to prevent leaching hazardous elements such as fluorine boron and heavy metals from the coal ash because the leaching concentrations of some elements in the ash exceed the Japanese standards for environmental soil quality. Through the laboratory experiments and mill trials we confirmed that the leaching concentrations of fluorine, boron and heavy metals were maintained below their environmental standards by mixing with fixation chemicals and curing for a short time.

• 농업과학연구
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• 제26권1호
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• pp.21-30
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• 1999

본 연구는 골판지고지의 가장 중요한 물성인 강도적 성질을 증대시키기 위하여 섬유의 전처리 방법으로서 Hobart mixer를 사용하여 섬유 내부의 결합제거 및 섬유표면에 Microcompression을 형성하여 개질처리 하였으며, 4가지 방법의 고해방법(Valley beater, Kady mill, Impact refining)을 채택하여 골판지고지의 최적고해 방법을 찾는데 그 목적을 두고 이 연구를 수행하였다. 그 결과는 다음과 같다. 1. 섬유장감소를 적게 유발하는 고해방법으로는 Kady mill과 PFI mill의 고해방법 이었으며 고해시 Curl을 펴주는 고해방법을 Kady mell과 Valley beater의 고해방법이 적절하였다. 2. 열단장은 Valley beating의 고해방법에 의하여 강도가 가장 많이 증가되었으며 인열강도는 가장 많이 감소하였다. 섬유전처리를 한 Comp-1과 Comp-2는 고해방식과 상관없이 열단장을 전체적으로 약 10% 증대시켰다. 3. 인열강도는 Comp-1, Comp-2의 전처리방법과 PFI mill 고해로 증대할수 있었다. 4. 파열강도는 Comp-1, Comp-2의 전처리방법과 Valley beater 고해로 증대할수 있었다. 5. 인열강도를 우지한채로 열단장을 가장 높이는 방법은 섬유전처리 방식인 Comp-1이나 Comp-2를 사용하여 Valley beating을 이용하는 방법으로 판단되었다.