• Journal of the Semiconductor & Display Technology
• /
• v.21 no.2
• /
• pp.144-149
• /
• 2022

A cryogenic Mixed Refrigerant Joule-Thomson refrigeration cycle was designed to be applied to the semiconductor etching process with non-flammable constituents. 3-stage cascade refrigerator, single mixed refrigerant Joule-Thomson refrigerator, and 2-stage cascade type mixed refrigerant Joule-Thomson refrigerator are analyzed to figure out the coefficient of performance. Non-flammable mixture of argon(Ar), tetrafluoromethane(R14), trifluoromethane (R23) and octafluoropropane(R218) were utilized to analyze the refrigeration cycle efficiency. The designed refrigeration cycle was adapted to cool down the coolant of HFE7200(Ethoxy-nonafluorobutane, C₄F₉OC₂H₅) with certain constraints. Maximum coefficient of performance of the refrigeration system is obtained as 0.289 for the cooling temperature lower than -100℃. The detailed result of the coefficient of performance according to the mixture composition is discussed in this study.

• Applied Chemistry for Engineering
• /
• v.22 no.1
• /
• pp.81-86
• /
• 2011

The aqueous solution of Sunset Yellow-FCF (SY-FCF) began to show schlieren texture at room temperature when its concentration reaches 25 wt%. A further increase of the concentration of SY-FCF to 28 wt% resulted in a perfect nematic liquid crystal phase. However, more than 30 wt% of SY-FCF in aqueous solution was required to make an optically anisotropic film simply by shear coating. In our study, concentration of SY-FCF solution, coating speed, drying temperature, and relative humidity were considered as coating parameters affecting the preparation of optically anisotropic thin films. From analysis of variance analysis (ANOVA), the solution concentration was revealed as a main factor affecting the film thickness. The drying temperature and solution concentration were main factors affecting the transmittance of parallel direction ($T_o$). Especially, SY-FCF aqueous solution with high concentration induced a better alignment of LC columns and produced highly oriented anisotropic films. In this study, optically anisotropic films prepared by 33 wt% of SY-FCF in aqueous solution showed 89.7~98.7% of degree of polarization.

• Clean Technology
• /
• v.13 no.3
• /
• pp.228-234
• /
• 2007

In this study, the productivity and environmental effects of laser aided direct metal deposition (LADMD) process which is one of promising rapid manufacturing technology is evaluated. The production time predicted using PowerMill shows that the productivity of LADMD is superior to that of conventional milling process. Though LADMD is known as an environment-friendly technology, it has a disadvantage to utilize much energy to generate laser beam. Considering both productivity and environmental effects, LADMD is expected to be widely used in remanufacturing industry.

• Monthly Duck's Village
• /
• s.225
• /
• pp.2-9
• /
• 2022

매년 찾아오는 가축 질병과 강화되는 정부 규제 등 생산기반이 위축되는 상황에서 현 오리사육 농가가 생산성을 높여야 할 필요가 있다고 느낀 청정오리농장 황문주 대표는 고상식 오리사를 도입했다. 고상식 오리사는 깔짚을 사용하지 않아 작업자가 오리사에 들어갈 필요가 없어 작업자로 인한 가축질병 감염 위험이 특히 적다. 또 단위면적당 사육수수 증가로 더 많아 소득에도 도움이 될 것으로 기대된다. 특히 최근 정부에서 가설건축물에 대한 축산업 허가를 불허하고 기존 가설건축물도 5년 이내 건축허가를 받아야만 한다. 청정오리농장은 기존 비닐하우스 축사를 보강해 무창 오리사로 리모델링을 통해 정식 건축허가를 받았다는 점도 주목할만하다. 기존 축사를 리모델링할 경우 신축 대비 비용도 1/3로 절감 가능하다는게 황 대표의 설명이며 축사에 대한 투자 여력이 부족한 오리농가들에게 대안으로 주목받고 있다. 이 뿐만 아니라 황문주 대표는 최근 새로운 도전에 나서고 있다. 축사 1동을 고상식 축사로 개조해 사육실험을 하고 있는 것이다. 고상식 축사는 깔짚이 필요없을 뿐만 아니라 환경개선으로 질병차단은 물론 생산성 향상에도 크게 도움이 되고 있다는 것이 황 대표의 설명이다.

• Clean Technology
• /
• v.9 no.3
• /
• pp.115-124
• /
• 2003

Bio industry had rapidly grown up to about 32% annualy mean since '90. To overcome a trade barrier related with environmental issues, which were needed to reduce and reuse pollutants generated from the manufacturing process of product to develop and apply cleaner technology. In this paper, the usefulness of membrane process were surveyed for economical and effective treatment of waste water which were discharged from the production of polymannuronic acid. Concentration efficiencies for U/F 10k, U/F 1k, and N/F were 40%, 60%, and 80% by batch operation. Concentration efficiencies for a combination process of U/F 1k and N/F were 90% by continuous operation. There were a lot of loss of product, which could improve 25% of productivity with recovering product by introducing membrane process.

• Clean Technology
• /
• v.9 no.2
• /
• pp.87-100
• /
• 2003

The aim of study was to suggest a methodology for applying cleaner production technology in dyeing & finishing process of textile materials. To accomplish cleaner production, we performed consulting activity in dyeing factory, which composed of following different procedures. First, we organized consulting team with specialists for dyeing, energy and chemicals, and visited dyeing companies for the purpose of doing basic investigation such as analysis of process, chemicals & effluents, condition of equipment and process flow of products. Environmental aspect of raw materials (dyestuff, chemicals) was assessed by TOC, COD, BOD, and effluent of that was assessed by TOC, COD, BOD, TDS and pH. Second, We find out the problems in dyeing&finishing process from the view point of dyeing process, energy, raw materials and process management by utilizing MB (material balance), LCA(Life Cycle Assessment), EB(Energy Balance). Third, we generated the solutions to achieve optimal process condition by brain storming method, and then implemented the solutions to each process. Finally, we determined their effectiveness after considering the results of repeating trials for the solutions. Cleaner production could be achieved by keeping optimal process conditions, equipment modification, improved production management, and on-site reuse or recycling.

• Clean Technology
• /
• v.15 no.2
• /
• pp.91-101
• /
• 2009

The metal complex dyes that are mainly used for good color fastness in dyeing amide fibers with highly concentrated colors usually contain toxic chromium. The remaining dye in th dyebath containing $Cr^{6+}$ causes not only environmental problems but also serious damages to human health. In this study, we applied reactive dyestuff for dyeing wool and nylon in order to substitute heavy metal dyestuff. The dyeing properties of reactive dyestuff in fibers as well as their absorption rates and fastness according to color concentration were investigated. By analyzing the quantity of heavy metals and toxic amine of reactive dyestuff, we investigated their harmfulness trends quantitatively. By comparing the reactive dyes with traditional metal complex dyes, we tried to find out the possibility of the reactive dye being a clean dyes in the future.

• Clean Technology
• /
• v.4 no.1
• /
• pp.45-59
• /
• 1998

Continuous immobilized-cell culture was carried out for the production of kasugamycin, a secondary metabolite by a filamentous bacteria, Streptomyces kasugaensis, with an intention of reducing waste generation. A sporulation medium was developed for production of bulk amounts of spores, and the spores were entrapped into celite biosupports for immobilization. It was possible to effectively keep the immobilized-cells inside the reactor during the continuous culture by an efficient immobilized cell separator of decantor type on the outlet of the fermentor. Using this continuous immobilized-cell fermentor system, we investigated the effects of feed substrate and phosphate concentrations on kasugamycin production and chemical oxygen demand(COD). Comparing with the conventional suspended-cell batch culture, the kasugamycin productivity was observed to increase by 2.5 times, whereas COD per unit kasugamycin production decreased by 2.3 times in the continuous immobilized-cell culture. Based on these results, the continuous immobilized-cell system was considered to be a cleaner bioprocess than the conventional batch suspended-cell system.

• Clean Technology
• /
• v.6 no.1
• /
• pp.1-6
• /
• 2000

In the Korean manufacturing industries, it becomes a common practice to carry both design activities and production planning activities concurrently. We should help product design engineers to apply environmental techniques in the design phase. General design engineers are busy enough to provide new technical features and to reduce the product cost. Professionals in the clean technology field should assist the product design engineers by providing the data basis of environmental specifications and appropriate solutions for each product group. This data basis should be easily accessible through internet or other forms appropriate for the personnel computers.

• Bulletin of Korea Environmental Preservation Association
• /
• v.19 no.4
• /
• pp.57-61
• /
• 1997