• Advanced Composite Materials
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• 제16권4호
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• pp.385-394
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• 2007

In this study, the effect of molding condition on the tensile properties for plain woven hemp fiber reinforced green composite was examined. The tensile properties of the composite were compared with those of the plain woven jute fiber composite fabricated by the same process. Emulsion type biodegradable resin or polypropylene sheet was used as matrix. The composites were processed by the compression molding where the molding temperature and its heating time were changed from 160 to $190^{\circ}C$ and from 15 to 25 min, respectively. The following results were obtained from the experiment. The tensile property of hemp fiber reinforced polypropylene is improved in comparison with polypropylene bulk. The strength of composite is about 2.6 times that of the resin bulk specimen. Hemp fiber is more effective than jute fiber as reinforcement for green composite from the viewpoint of strength. The molding temperature and time are suitable below $180^{\circ}C$ and 20 min for hemp fiber reinforced green composite. Hemp fiber green composite has a tendency to decrease its tensile strength when fiber content is over 50 wt%.

• 한국태양에너지학회 논문집
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• 제30권6호
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• pp.34-43
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• 2010

Recently environmental regulations like the Kyoto Protocol, adopted in 1997, required the reduction of the greenhouse gas of 5.2% up to 1990 regulations. and 13th General Assembly in 2007, held in Bali of India, have agreed to duty reduction even in developing countries in 2013. Because of the lack of information about real process in small or middle size industries, most recent research omitted to calculate green house gas emissions from the industrial process. Bottom-up methodology will be applied for calculation of green house gasemission from industry sector to solve these problems in this research. Total amount from industry sector of Shicheung-City in 2007 was about 1,797,305 tons of greenhouse gas $CO_2$ and 3,049,403 tons of the greenhouse gas $CO_2$ calculated from industry sector of Ansan-City in 2007.

• Journal of electromagnetic engineering and science
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• 제7권2호
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• pp.59-63
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• 2007

This paper suggests a novel method to efficiently calculate the spatial-domain Green's functions of 2D electromagnetic problems Briefly speaking, this method combines spectral and spatial domain calculation schemes and prevents the Green's functions from poor convergence due to the singularities that complicate the process of the Method of Moment(MoM) applications For the validation of this proposed method, fields will be evaluated along the spatial distance including zero distance for 2D free-space and periodic homogeneous geometry The numerical results show the validity of the prosed method and correspondng physics.

• 한국전기전자재료학회논문지
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• 제36권5호
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• pp.494-499
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• 2023

In this paper, in order to apply the CF (color filter) type of the micro light emitting device (Micro LED) display method, a study on the manufacturing process of red and green phosphor inks for the inkjet process was conducted. The blue light-emitting KSF and LuAG phosphors were respectively used to control the phosphor particle size to about 1㎛, and a phosphor ink was prepared by synthesizing with a low-viscosity solution (IPA/Eg). A chemical dispersion method was applied to selectively control the dispersion characteristics in the manufacture of phosphor inks, and in particular, phosphor inks with a dispersant applied a dispersant secured stable dispersion characteristic compared to phosphor inks without a dispersion process. Therefore, it seems possible to manufacture CF for Micro LED through an inkjet process capable of controlling the dispersion characteristics of phosphor ink.

• 에너지공학
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• 제29권3호
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• pp.50-56
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• 2020

Currently, 3D printing technology is a new revolutionary additive manufacturing process that can be used for making three dimensional solid objects from digital films. In 2019, this 3D printing technology spreading vigorously in production parts (57%), bridge production (39%), tooling, fixtures, jigs (37%), repair, and maintenance (38%). The applications of 3D printing are expanding to the defense, aerospace, medical field, and automobile industry. The raw materials are playing a key role in 3D printing. Various additive materials such as plastics, polymers, resins, steel, and metals are used for 3D printing to create a variety of designs. The main advantage of the green cement for 3D printing is to enhance the mechanical properties, and durability to meet the high-quality material using in construction. There are several advantages with 3D printing is a limited waste generation, eco-friendly process, economy, 20 times faster, and less time-consuming. This research article reveals that the role of green cement as an additive material for 3D printing.

• 한국생산제조학회지
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• 제25권1호
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• pp.14-20
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• 2016

This paper describes a green stripping process to effectively strip the remaining DFR layer on a non-alkali-based ITO glass surface after an etching process. A stripper, water-soluble amine compound, is used to investigate the characteristics of stripping ability and to suggest a valid method for the green process. Increasing the composition (5-30% concentration) of the ethanol amine-based stripper was found to greatly reduce the stripping time applied in the dipping method. The composition (30%) achieved an excellent stripping effect and free-residue impurities. Additionally, it was possible to obtain the effect of stripping in a way to sustain the release before generating DFR sludge from the ITO glass surface by using dipping condition (stripping time) in the composition. An Additional stripping process (buffering) out of dipping can realize productivity improvement and cost reduction because of the higher proportion of re-use of the stripping solution used in the DFR removal step.

• Natural Product Sciences
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• 제25권2호
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• pp.150-156
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• 2019

Conventional extraction of oil and azadirachtin, a botanical insecticide, from Azadirachta indica involves defatting the seeds and leaves using hexane followed by azadirachtin extraction with a polar solvent. In order to simplify the process while maintaining the yield we explored a binary extraction approach using Soxhlet extraction device and hexane and ethanol as non-polar and polar solvents at various ratios and extraction times. The highest oil and azadirachtin yields were obtained at 6 h extraction time using a 50:50 solvent mixture for both neem leaves (44.7 wt%, $720mg_{Aza}/kg_{leaves}$) and seeds (53.5 wt%, $1045mg_{Aza}/kg_{leaves}$), respectively.

• Korean Chemical Engineering Research
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• 제60권1호
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• pp.25-33
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• 2022

본 연구에서는 흑액 증발공정에 소비되는 스팀의 절감량을 예측하기 위해 증발기 수에 따른 다중 효용 증발공정 모델을 개발하였다. 개발한 공정 모델은 흑액의 예열 및 증발 과정으로 구성되어 있고, 스팀 사용량을 예측하기 위해 가상의 재비기가 추가되었다. 시뮬레이션 결과, 2중 효용 증발기에서 스팀 사용량은 48.9% 감소하였고, 증발기 수가 증가함에 따라 스팀 사용량이 감소하여 8중 효용 증발기에서 최대 76.5% 감소함을 확인하였다. 시뮬레이션 결과를 증발기 수에 따른 포화증기의 잠열 회수량, 스팀 사용량, 각 증발기의 포화증기 생산량으로 분석하여 최적의 증발기 수 도출을 위한 방안을 제시하였다.

• 한국재료학회지
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• 제11권10호
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• pp.869-878
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• 2001

Alumina $(Al_2O_3)$ green bodies were fabricated by gel-casting using three kinds of alumina with different particle size (mean particle size: 4.6 $\mu\textrm{m}$, 0.32 $\mu\textrm{m}$, 10nm). The effects of particle size on gel-casting process and green microstructure were investigated. The optimum dispersion conditions using ammonium salt (D-3019) as dispersant were 0.2 wt% (4.63 $\mu\textrm{m}$), 0.5 wt% (0.32 $\mu\textrm{m}$), and 5.0 wt% (10 nm), in high solid loading. The optimum solid loading of each starting material for gel-casting was obtained as 59 vol% (4.63 $\mu\textrm{m}$), 57 vol% (0.32 $\mu\textrm{m}$), 15 vol% (10 nm), depending on particle size, indicating that nano-size particle (10 nm) represent lower solid loading as high specific surface area than those of other two starting materials. The drying at ambient conditions (humidity; $\thickapprox$90%) was performed more than 48hrs to enable ejection of the part from the mold and then at $120^{\circ}C$ for 2hrs in an air oven, showing no crack and flaw in the dried green bodies. The pore size and distribution of the gelcast green bodies showed the significant decrease with decreasing particle size. Green microstructure was dependent on the pore size and distribution due to the particle size, and on the deairing step. The green density maximum obtained was 58.9% (4.63 $\mu\textrm{m}$), 60% (0.32 $\mu\textrm{m}$), 47% (10 nm) theoretical density (TD), and the deairing step applied before gel-casting did not affect green density.

• 한국건설관리학회논문집
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• 제18권2호
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• pp.3-11
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• 2017

내 공공건축물은 총 17만 7천여 동으로 이중 15년 이상 경과하여 노후화가 진행 중인 건물이 전체 건물 수의 약 74% 달한다. 노후화된 건물로 인하여 에너지 손실이 심각한 실정이다. 노후화 건축물의 에너지 효율을 개선하여 에너지 소비량을 줄이기 위해서 정부 및 지자체에서 기존 건축물의 리모델링 수선 및 설비 교체를 통한 에너지 효율화 사업을 진행 중이다. 최근에 개정된 녹색건축물 조성지원법에서는 그린리모델링을 기존 공공건축물에 적용 활성화하고자 한다. 하지만 그린리모델링 사업에 대한 업무의 범위, 재원 마련 방안 및 발주 방식에 대한 기준이 뚜렷하지 않다. 따라서 본 연구를 통하여 그린리모델링을 활성화 할 수 있는 방안을 마련하고자 한다. 기존 건축생산 과정을 바탕으로 한 프로젝트 라이프사이클 과정에서 발생하는 업무를 기준으로 그린 리모델링 업무를 정의하였으며, 건축주 및 사업자가 재원을 마련 할 수 있는 방안 및 그린리모델링 업무 구분에 따른 발주 패키지를 도출하여 낙찰자 결정 방식 및 대가지급 방식 등을 제안하였다.