• Journal of Powder Materials
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• v.27 no.3
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• pp.256-267
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• 2020

Metal additive manufacturing (AM) technologies are classified into two groups according to the consolidation mechanisms and densification degrees of the as-built parts. Densified parts are obtained via a single-step process such as powder bed fusion, directed energy deposition, and sheet lamination AM technologies. Conversely, green bodies are consolidated with the aid of binder phases in multi-step processes such as binder jetting and material extrusion AM. Green-body part shapes are sustained by binder phases, which are removed for the debinding process. Chemical and/or thermal debinding processes are usually devised to enhance debinding kinetics. The pathways to final densification of the green parts are sintering and/or molten metal infiltration. With respect to innovation types, the multi-step metal AM process allows conventional powder metallurgy manufacturing to be innovated continuously. Eliminating cost/time-consuming molds, enlarged 3D design freedom, and wide material selectivity create opportunities for the industrial adoption of multi-step AM technologies. In addition, knowledge of powders and powder metallurgy fuel advances of multi-step AM technologies. In the present study, multi-step AM technologies are briefly introduced from the viewpoint of the entire manufacturing lifecycle.

• Applied Chemistry for Engineering
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• v.31 no.6
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• pp.660-667
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• 2020

This study focused on the epoxy resin production process, which uses the steam of 155 ℃ or higher as a heat source, and discards all condensate generated. A part of the process is operated at low temperatures of 70 ℃ or below, thus there are opportunities to reduce the steam consumption by recycling wasted condensate as a heat source for the low temperature section of process. In this study, we developed process models that can reduce steam by recovering waste heat through recycling condensate and conducted a case study to find an optimal condensate recycling system. Three different process designs were proposed and economic evaluations were performed by comparing annual capital costs and steam savings in each case. Finally, an annual steam consumption of the low-temperature section could be reduced by up to 67.6%, which could also bring an additional economic benefit of 522.1 million won/yr.

• Journal of the Korean Ceramic Society
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• v.47 no.6
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• pp.613-617
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• 2010

Ferro-Nickel slag is one of the by-products in Ferro-Nickel manufacturing process. The slag is composed of $SiO_2$, MgO, $Fe_2O_3$ and others. But the slag has been buried at landfill despite having valuable elements. This study tried to extract Mg ion and fabricate Mg compound from ferro-nickel slag using hydrochloric acid solution. Mg ion was extracted with Si, Fe and other ions in HCl solution. So reprocess was needed for gaining high purity Mg ion. It was thought that Si ion or $SiO_2$ precipitated in HCl solution and removed from solution in filtering process. Fe ion converted into $Fe(OH)_3$ after reacted with $NH_4OH$ and precipitated in HCl solution. After these process, the filtrate was composed of high purity Mg ion. $MgCl_2{\cdot}NH_4Cl{\cdot}6H_2O$ was obtained through drying of filtrate and this product was changed into MgO by burning process ($600^{\circ}C$-30 min). That is, 1st material or solution for manufacturing 2nd product was fabricated using acid dissolution method and other treatments.

• Korean Chemical Engineering Research
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• v.60 no.1
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• pp.25-33
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• 2022

This study developed the black liquor evaporation process models using the multiple-effect-evaporator according to the number of effects to predict steam consumption. The developed models were divided into the black liquor preheating and evaporation processes, and a virtual reboiler was added to predict steam consumption. In simulation results, the steam consumption in the double-effect-evaporator was decreased by 48.9 %, and as the number of effects increased, the steam consumption was decreased. Finally, the steam consumption in the octuple-effect-evaporator was decreased by 61.2 %. Also, this study suggests a strategy for deriving the optimal number of effects in the process by analyzing the latent heat recovered from the saturated vapor produced in the multiple-effect-evaporator and the amount of saturated vapor produced by each effect.

• KIEAE Journal
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• v.12 no.5
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• pp.43-52
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• 2012

This study aims to analyze the green strategies of laboratory buildings in the U.S. developed by LABS21 and LEED of USGBC. To achieve this goal, the paper analyzed the design process of green laboratories and the sustainable planning strategies. Laboratories, as a building type, have specific requirments stipulated by NIH. Chemical restive measures and biosafety level measures needed to be met in laboratory buildings prior to meeting green measures. Obama Admistration's Executive Order 13514 in mind, the paper has mainly focused on the five areas of green planning strategies in the laboratory buildings; site, energy, water, indoor environment, and materials. The study informed that the current green certification program needs to expand into the particular building types in order to; first, provide more realistic energy-saving benchmarking data, and second, provide building-type-specific green strategies.

• Journal of Distribution Science
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• v.17 no.9
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• pp.57-66
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• 2019

Purpose - This study aimed at investigating the process of inducing the effect of green self-expressive motive and the fit between green premium and product on consumer's intent to purchase the bundle product with the green premium. Research design, data, and methodology - The questionnaire for on-line survey built at Google Forms was spread out via popular social media sites. 243 responses from the on-line survey were used for testing the hypotheses. Structural equation model of Amos 21.0 was used to verify hypotheses. Results and Conclusions - Green self-expressive motive positively influenced on not only the perceived value for green premium but also attitude toward the bundle. However, the fit between green premium and product had positive impact only on the perceived value for green premium. The perceived value was proved to positively influence on the attitude toward the bundle, which in turn increased the purchase intention, even with the positive effects of the product attitude as covariate on the intention. Therefore, marketers should choose target customers who have high level of green self-expressive motive and feel the fit, and pay attention to the green premium to help the customers perceive more values for the green premium. They should develop green premium product for conducting marketing effectively.

• Membrane Journal
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• v.34 no.1
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• pp.79-86
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• 2024

The flat sheet membrane, one of the representative forms of polymeric membranes, is widely used from material research in laboratories to commercial membrane production due to its ease of fabrication. Porous polymeric flat sheet membranes used in microfiltration and ultrafiltration are mainly fabricated through phase separation processes, utilizing non-solvent-induced and vapor-induced phase separation methods. However, due to the nature of phase separation processes, variations between samples can easily occur depending on the surrounding environment and the experimenter, making it difficult to ensure reproducibility. Therefore, for scaling up and ensuring reproducibility of developed membrane fabrication technologies, there is a need for a controlled environment continuous large-area production device, such as a roll-to-roll manufacturing system. This research compared the changes in membrane characteristics due to differences in manufacturing environments when scaling up laboratory-scale fabrication technologies to roll-to-roll processes using knife and slot die coaters. By optimizing the continuous manufacturing process factors, uniformity of the membrane was ensured during large-area production.

• Journal of Energy Engineering
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• v.29 no.3
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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.

• KIEAE Journal
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• v.12 no.1
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• pp.83-90
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• 2012

Over the world, social demands and concerns of energy and resource depletions and environmental conservation have resulted in many researches and applications on sustainable development and construction. In order to support these demands and concerns, international green building certification systems such as LEED(Leadership in Energy and Environmental Design) and BREEAM(Building Research Establishment Environmental Assessment Method) were developed. In Korea, the green building certification system was introduced in 2000 and widely applied to all types of new buildings in order to induce the diffusion of sustainable buildings on May, 2010. This paper investigates the importance of assessment criteria on multi-unit apartment projects among certification rating systems using the AHP(Analytic Hierarchy Process) method and suggests a new direction on certification assessment standards. For applying the AHP method, the survey of staffs in green building certification consulting companies and architectural design companies was conducted via e-mail. As a result, criteria like energy, indoor environment, land use, pollution control, and ecological environment among 9 main ones turned out important on assessing green building certification at multi-unit apartment projects, while criteria like water resource, transportation, maintenance management, and material and resource did relatively unimportant.

• Korean Chemical Engineering Research
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• v.56 no.6
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• pp.878-883
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• 2018

A circulating fluidized bed (CFB) has been used in various chemical industries because of good heat and mass transfer. In addition, the methanol to olefins (MTO) process requiring the CFB reactor has attracted a great deal of interest due to steep increase of oil price. To design a CFB reactor for MTO pilot process, therefore, we has examined the hydrodynamic properties of spherical catalysts with different particle size and developed a correlation equation to predict catalyst holdup in a riser of CFB reactor. The hydrodynamics of micro-spherical catalysts with average particle size of 53, 90 and 140 mm was evaluated in a $0.025m-ID{\times}4m-high$ CFB riser. We also developed a model described by a decay coefficient to predict solid hold-up distribution in the riser. The decay coefficient developed in this study could be expressed as a function of Froude number and dimensionless velocity ratio. This model could predict well the experimental data obtained from this work.