• Structural Engineering and Mechanics
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• 제76권5호
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• pp.561-578
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• 2020

The present work addresses the surface integrity and chip morphology in finish hard turning of AISI D3 steel under nanofluid assisted minimum quantity lubrication (NFMQL) condition. The surface integrity aspects include microhardness, residual stress, white layer formation, machined surface morphology, and surface roughness. This experimental investigation aims to explore the feasibility of low-cost multilayer (TiCN/Al2O3/TiN) coated carbide tool in hard machining applications and to assess the propitious role of minimum quantity lubrication using graphene nanoparticles enriched eco-friendly radiator coolant based nano-cutting fluid for machinability improvement of hardened steel. Combined approach of central composite design (CCD) - analysis of variance (ANOVA), desirability function analysis, and response surface methodology (RSM) have been subsequently employed for experimental investigation, predictive modelling and optimization of surface roughness. With a motivational philosophy of "Go Green-Think Green-Act Green", the work also deals with economic analysis, and sustainability assessment under environmental-friendly NFMQL condition. Results showed that machining with nanofluid-MQL provided an effective cooling-lubrication strategy, safer and cleaner production, environmental friendliness and assisted to improve sustainability.

• 자원환경지질
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• 제41권5호
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• pp.497-507
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• 2008

본 연구는 국내 5대 수출 품목 중 하나이며, 국내 주요 수출품의 원자재로서 지속가능한 자원관리의 파급효과가 큰 철강을 대상으로 히든플로우와 물질집중도를 MIPS방법론을 이용하여 정량화하였다. 2005년에 4.8천톤의 철강재와 17.6백만달러(2000년 기준)의 부가가치를 생산하기 위해 71백만톤의 윈재료와 18백만Toe의 에너지를 사용하였다. 이러한 원재료와 에너지사용으로 인한 천연자원사용량은 TMR(total Material Requirement, 총물질요구량) 245백만톤, water 1524백만톤, air 34백만톤이었다. 그리고 material intensity, 즉 철강재 1톤을 생산하기 위해서 TMR 4.3톤, water 28톤, air 0.5톤의 자연자원이 사용되었다.

• 한국산학기술학회논문지
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• 제18권11호
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• pp.263-281
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• 2017

일관제철소의 모든 공정은 서로 연결됨으로써 단일공정에서의 효율성을 향상시킬 수 있는 최적화도 중요하지만 무엇보다도 전체 공정의 연결 관점에서의 최적화가 중요하다. 일관제철소에서의 경영과학 모형 적용에 관한 조사연구는 대부분 특정 공정만을 대상으로 문제해결을 위한 모형에 집중하고 있거나 혹은 일관제철소에서 발생되는 문제에 대해 어떤 기법이 적용되고 있는지에 대한 조사에 집중되고 있다. 그러나 이보다는 일관제철소에서 해결되어야만 하는 문제를 우선 정의하고, 이를 모형화 할 수 있는 목적과제약조건 등에 대해 파악하며, 현실적으로 적용 가능한 해를 구할 수 있는 방법론이무엇인지에 대한 연구가 어떻게 이루어져 왔는지에 대해 조사가 필요하다. 이 연구에서는 일관제철소 공정을 대상으로 생산운영관리관점에서의 효율성 향상을 위해 필요한 연구가 무엇인지를 기술한 후, 이를 해결하기 위해 어떤 연구들이 진행되어 왔는지에 대해 조사하였다. 이를 위해 6가지 영역으로 분류하여 기존 연구에 대해 조사하였으며, 전체최적화 관점에서 향후의 연구방안에 대해 제시하였다. 이를 바탕으로 일관제철소에서의 공정 효율성 제고를 위한 연구주제가도출될 수 있을 것으로 기대된다.

• Corrosion Science and Technology
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• 제22권2호
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• pp.73-89
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• 2023

Due to continuous promotion of green alternatives to toxic petrochemicals by government policies, research efforts towards the development of green corrosion inhibitors have intensified recently. The objective of the current work was to develop novel green and sustainable corrosion inhibitors derived from 4-aminoantipyrine to effectively prevent corrosion of mild steel in corrosive environments. Gravimetric methods were used to investigate corrosion inhibition of 4-((furan-2-ylmethylene)amino)antipyrine (FAP) and 4-((pyridin-2-ylmethylene)amino)antipyrine (PAP) for mild steel in 1 M HCl. FAP and PAP were subjected to quantum chemical calculations using density functional theory (DFT). DFT was used to determine the mechanism of mild steel corrosion inhibition using inhibitors tested in HCl. Results demonstrated that these tested inhibitors could effectively inhibit mild steel corrosion in 1.0 M HCl. At 0.0005 M, these inhibitors' efficiencies for FAP and PAP were 93.3% and 96.5%, respectively. The Langmuir adsorption isotherm was obeyed by these inhibitors on the mild steel surface. Values of adsorption free energies, ΔG^o_ads, revealed that FAP followed chemical and physical adsorptions.

• 교육시설
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• 제11권1호
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• pp.47-57
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• 2004

The Architects' design process is subjective and mysterious'. If we can reveal this process, it will be very helpful to proceed similar design projects. In the aspect of steel production, Korea is a strong country, but in the aspect of steel usage, Korea does not show its impacts as compared with other countries'. Even though steel has many merits in design as well as in structure, in Korea we have not applied it as design elements. In this situation, the demand of steel in school buildings is increasing, but steel also is used only on the basis of the structural and material meaning. So this thesis tries to find design elements of steel structure buildings, which can be applied in school buildings, through the analysis of existing steel structure buildings and the characteristics of steel.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1999년도 춘계학술대회논문집
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• pp.273-279
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• 1999

In this paper the stress and strain behaivor in near homogeneous isotropic matrix of metal like steel was studied roll forming of thin steel sheet for cylindrical pipe. Analytical results reveals a body which is on the area of square thickness along and perpendicular to the width of thin steel sheet is in the state of plane strain during roll forming. As a result construction of analytical method for calculating deformation load and stably deformed length along the width of strained steel sheet was established. Also loads applied during roll forming were analyzed using two typical thin steel sheet 12.3m thick steel sheet with 42.5kg /mm2 yield strength of pipe and 5.3mm thick steel sheet with 32.5kg/mm2 yield strength of pipe. Through this analysis applicability of the analytical method for deformation load during roll forming of cylindrical thin steel pipe was evaluated with a study of necessary production technology for roll forming and design technology for roll forming machine.

• 소성∙가공
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• 제8권6호
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• pp.554-562
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• 1999

In this paper, the stress and strain behavior in near homogeneous isotropic matrix of metal like steel was studied during roll forming of thin steel sheet for cylindrical pipe. Analytical result reveals a body which is on the area of square thickness along and perpendicular to the width of thin steel sheet is in the state of plane strain during roll forming. As a result, construction of analytical method for calculating deformation load and stably deformed length along the width of strained steel sheet was established. Also, loads applied during roll forming were analyzed using two typical thin steel sheets. 12.3mm thick steel sheet with 42.5kg/㎟ yield strength of pipe and 5.3mm thick steel sheet with 32.5kg/㎟ yield strength of pipe. Through this analysis, applicability of the analytical method for deformation load during roll forming of cylindrical thin steel pipe was evaluated with a study of necessary production technology for roll forming and design technology for roll forming machine.

• 한국경영과학회지
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• 제34권2호
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• pp.77-90
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• 2009

Total profit level Increases if a company increase the cost for achieving R&D related goals of equipment productivity enhancement, production cost saving, or for achieving equipment scale target, sales volume goal. But how much money should be invested to achieve a certain level of profit? We formulated the model to set the optimal goal levels to minimize the investment cost under the constraint that certain level of total profit should be guaranteed. This model derived from a case of P steel company. We found that this should be considered in relation with the production sales planning (known as optimal product mix problem) to guarantee the profit. We suggested a nonlinear programming model, 3 valiant form of the p+roduct mix problem. We can find the optimal Investment level for the R&D related goals or sales volume goal, equipment scale target for the P steel company using the model.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2008년도 추계학술대회 초록집
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• pp.137-137
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• 2008

This paper presents the ability of plasma electrolytic polishing technology to polish surface of stainless steel materials. The results show that the surface of its can be polished clearly using potentiostatic regimes in various concentration of $(NH_4)_2SO_4$ solution that had been warmed to a certain initial temperature. The equipment and deposition produces for polishing process are described and the effect of processing parameters on the characterizations polishedsamples has been has been investigated.

• 한국식품저장유통학회지
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• 제24권7호
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• pp.915-922
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• 2017

양파의 관행 수확과 저장 방식을 개선하여 벌크 상태로 수확하여 수송, 하역, 보관 및 저장할 수 있도록 톤백 및 와이어철제파렛트를 개발한 후 관행저장 방식과 벌크저장 후 저장성을 비교하고 그에 따른 노동투입시간 및 소요비용을 비교하여 양파의 산지물류비 절감 효과를 비교 분석하고자 하였다. 본 연구를 통해 개발된 톤백이 관행 톤백보다 길이방향 인장강도가 16% 높았으며, 개발한 와이어철제파렛트가 관행철제파렛트보다 약 10% 더 저장가능하고 차량 적재 효율도 2배 이상 향상되었다. 개발된 500 kg용 와이어 철제파렛트의 벌크저장과 관행 그물망 저장의 감모율에는 차이가 없었으나, 1,000 kg 이상 많은 양을 저장할 경우 와이어철제파렛트 벌크저장은 관행저장보다 감모율이 3.7% 높아 적합하지 않는 것으로 나타났다. 톤백을 이용한 벌크 수확이 관행 망 수확보다 노동시간이 50.1% 그리고 총 투입비용은 46.1% 감소할 수 있는 것으로 나타났다. 와이어철제파렛트를 적용한 벌크저장이 관행저장보다 총 저장비용이 28.8% 감소하였으며, 2016년 양파생산량(1,298,749톤)의 30%를 와이어철제파렛트 벌크저장으로 대체할 경우 연간 183억 원을 절감할 것으로 추정된다. 따라서 현재 산지업체들의 와이어철제파렛트를 조기 도입하여 정착시키면 전국적으로 노동력 및 비용 절감에 상당한 효과가 있을 것으로 판단된다.