• 품질경영학회지
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• 제22권4호
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• pp.152-159
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• 1994

A study of improvement of printing accuracy of special PCB has been carried out by applying the corrected data of laminate dimensional variation to real products. The result of this study improved the accuracy of product by decreasing the deviation between design specifications and end products. This paper will be useful when PCB manufacturers using paper phenol laminates make preparation for customer's needs, more complicated specifications. And so, it will be successful for image renovation of any company by assuring the reliabilities to customers.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2014년도 춘계 학술논문 발표대회
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• pp.254-255
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• 2014

This study is a part of development to improve early-age compressive strength of concrete by using industrial by-products. It tried to investigate the characteristics of early-age compressive strength according to curing temperature and industrial by-product replacement ratio 10, 20, and 30 %. As a result, regardless of industrial by-product replacement ratio and age, early-age compressive strength of concrete was found to be high compared to Plain using 100 % cement.

• 한국해양바이오학회지
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• 제15권2호
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• pp.67-81
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• 2023

This study examines a business survey on the utilization of fishery by-products with the aim to assess the feasibility of incorporating these by-products into various industries. The research involved surveying 312 biocompanies across the country and conducting an empirical analysis based on the collected data. South Korea, a leading seafood-producing country with a developed seafood processing industry, provides conditions necessary to utilize seafood by-products as raw materials for the marine bioindustry. Among the surveyed biocompanies, 38.5% expressed their intention to engage in industrial activities involving the use of fishery by-products in the future, indicating a significant level of interest within the bioindustry in utilizing marine and fishery by-products. Companies showed interest in diverse materials, such as scales, fish bones, skin, and kelp holdfast beyond those currently defined under the Fisheries By-products Recycling Promotion Act (officially unnamed, 2021). This suggests a need for improvements in the regulatory framework to accommodate these diverse biomaterials. Furthermore, we propose enhancing the efficiency of fishery by-product utilization by focusing on regional specialization in marine bioindustry. This involves utilizing existing legal framework for upcycling fishery by-products and fostering a regionally specialized marine bioindustry.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 봄 학술발표회 논문집
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• pp.707-714
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• 2001

This paper presents the fundamental study on rational manu(acture of Very High Strength(VHS) concrete using industrial by-products as like silica fume, slag and fly ash. In this study, we had tested various mixing cases to manufacture the VHS concrete(target compressive strength : over 1,000 kgf/$cm^{2}$) which is easily workable (target slump flow : 60$\pm$l0cm), The main variables studied are; 1) test variables to find the optimum replacement ratio of mineral admixture, 2) test variables to find a rational water-binder ratio, a proper binder content, 3) test variables to find the method for reduction of slump loss, 4) test variables to know the influence of air entrainment on frost resistance. From the test results, it is concluded that the rational mix design can be made by using 40% slag, 10% silica fume, and water reducing agent(slump loss reduction type). We found that it is unnecessary to entrain air for freeze-thawing resistance.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2012년도 추계 학술논문 발표대회
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• pp.213-214
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• 2012

This study is about the assessment of utilization possibility as a material for cementation of ground which is necessary for the reinforcement of soft ground by making environment-friendly inorganic composite utilizing inorganic recycled resources, and it was verified that it showed higher uniaxial compressive strength than the existing cementitious ground solidifier when it was applied as a combination material for soft ground such as dredge reclaimed land, and since an inorganic composite utilizing recycled resources such as high calcium fly ash and blast furnace slag etc. does never use cement, it is considered that it would be safe in the issue of a hexavalent chromium that was recognized as a problem of a cementitious solidifier.

• 대한산업공학회지
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• 제23권3호
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• pp.545-557
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• 1997

This paper deals with dynamic optimal pricing for new products by a firm which maximizes the discounted profit stream of it's own in a duopoly. The problem is constructed as differential games and dynamic optimization theory. Cost is assumed to decline as time goes on. A modified customer's choice model is formulated as a diffusion model and we solve a dynamic optimization problem by adopting the diffusion model. Since this paper focus on deriving real prices not showing a time trend, we formulate recursive form equations of costate variables(shadow price) and a simultaneous equation of price. Hence we derive a dynamic optimal pricing model for using in real market. In particular, we construct a dynamic optimal pricing model in the case that there are benefits from not only new subscribers but also previous subscribers. We analyze instant camera market in U.S.A(1976-1985) by utilizing the above model.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1998년도 가을 학술발표대회 논문집(III)
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• pp.888-893
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• 1998

Calcium sulfoaluminate, $C_4$A$_3$$\bar{S}$, was prepared for reutilizing industrial by-products, such as II-CaSO$_4$, Al(OH), CaF$_2$ and cement sludge wastes. Mixed powder was fired at 1,15$0^{\circ}C$. $C_4$A$_3$$\bar{S}$ clinkers fired at 1,15$0^{\circ}C$ were analyzed by SEM and XRD. Also were added in cement paste and mortar and characterized as setting time, flow values and compressive strength. $C_4$A$_3$$\bar{S}$ could be found in the X-ray diffraction pattern. The setting time of cement pastes added clinkers fired at 1,15$0^{\circ}C$ was shorter than that of ordinary portland cement. Also the compressive strengths of the cement mortar added clinkers was higher than those of ordinary portland cement.

• 한국구조물진단유지관리공학회 논문집
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• 제5권3호
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• pp.153-162
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• 2001

This paper presents the fundamental study on rational manufacture of Ultra High Strength(VHS) concrete using industrial by-products as like silica fume, slag and fly ash. In this study, we had tested various mixing cases to manufacture the UHS concrete(target compressive strength : over $1,000kgf/cm^2$) which is easily workable (target slump flow : $60{\pm}10cm$). The main variables are studied: 1) to find the optimum replacement ratio of mineral admixture. 2) to find a rational water-binder ratio and a proper binder content. 3) to find the method for reduction of slump loss. From the test results, it is concluded that the rational mix design can be made by using 40% slag, 10% silica fume. We found that compressive strength of UHS concrete increases according to decreasing W/B ratio but in W/B ratio 18~20%, the difference is vague and the compressive strength does not necessarily increase according to increasing binder content over 700kg.

• 한국재료학회지
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• 제20권4호
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• pp.181-186
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• 2010

Since it was developed by Joseph Aspdin, cement has been a common construction materials up to the present time. However, there are trace constituents in cement clinker. One of the trace constituents included in cement clinker, chromium, has become prominent and highly noticed lately as a social issue both inside and outside of this country because it affects the human body negatively. The aim of the present study was to investigate the concentration of water-soluble hexavalent chromium in cement clinker by using industrial by-products. For that reason, raw materials were prepared to add different $SiO_2$, $Al_2O_3$, and $Fe_2O_3$ sources. After the raw materials such as the limestone, the sand and the clay, iron ore was pulverized and mixed, and the raw meal was burnt at about $1450^{\circ}C$ in a furnace with an oxidizing atmosphere. The part in the raw materials of the clinker was substituted with slag, sludge, etc. and this was used to manufacturing cement clinker. To investigate the water-soluble hexavalent chromium content in clinker, raw meal was prepared by changing the modulus, the type, and the content of clinker materials and tested concentrations of hexavalent chromium in the clinkers. To determine $Cr^{+6}$ formation of the clinker, tests were done with raw meals adding chromium by using different industrial by-products. Consequently because the chromium was to be included in the raw materials of the clinker, production of Portland cement clinker was included with the chromium. Also, the chromium was converted into hexavalent chromium in the burning process.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2003년도 Proceedings of the international symposium on the fusion technology
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• pp.573-580
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• 2003

In Taiwan there are 21 Municipal Solid Waste Incinerators (MSWI) built to treat 80% of the MSW nationwide. Approximately 2,000 tons of incineration ashes of municipal waste contain reaction ash and fly ash (3:1 by weight)will be produced daily, and this may cause a serious waste problem. According to EPA regulations, reaction ash and fly ash produced after incineration should be properly treated. Landfill capacity barely meets the general demands. More efficient actions should be planned and taken. The study found 'reclamation' should be the optimal solution to this problem. Only limited research and previous successful experiences are available among other countries. An incinerator in Northern Taiwan is chosen for this study to make environmental bricks from the reaction ash and fly ash. From the previous tests, the results of strength test were measured. From the previous test results, the fly ash products have not reached the desired strength; hence, reaction ash is chosen for further pilot study. In the experiment, incineration ashes, cement and gravel are mixed in the ratio of 1:1:1(by weight), to ground concretization aggregate and pelletization aggregate, the concrete products made from the aggregates were of the strength of 108 $kgf/cm^2$ and 142 $kgf/cm^2$ individually. For the purpose of making nonstructural walls which met the State Building Standards. In the study, 50 tons of concrete products was yielded from aggregate and environmental bricks. Further observation and supervision are recommended to ascertain the resource recycling and reclamation. EPA has planned to build three 'Recycling Plants' in northern, middle and southern Taiwan to develop efficient techniques to produce concrete products, sub-base course, soundproofing wall, gravel, artificial fishing reefs, tiles, drainage, bricks and etc. This experiment of the demonstrative plant solves the problem of the incineration ashes and opens another opportunity to reclaim them.