Preliminary micro-characteristics analysis of municipal solid waste incineration fly ash treated by geocasting and calcination

( Giun Jo ),( Patcharanat Kaewmee ),( Yu Tian ),( Mengzhu Song ),( Astryd Viandila Dahlan ),( Fumitake Takahashi ) 한국폐기물자원순환학회(구 한국폐기물학회) 2018 한국폐기물자원순환학회 심포지움 Vol.2018 No.1

Municipal solid waste (MSW) generation is increasing rapidly since 20^th century. For reducing volume and weight of MSW, incineration is one of the major treatments. Major products of municipal solid waste incineration (MSWI) are bottom ash and fly ash. MSWI Fly ash contains heavy metals like Pb and Zn. In order to immobilize hazardous heavy metals in fly ash, some treatments are used such as chelate treatment. However, chelate treatment has possibility of chemical/biological decomposition and cause long-term high concentration of organic hydrocarbons in landfill site as well as leaching of heavy metals to the environment. In this study, the authors focus on the alternative treatment. Fly ash can be replaced fluidized bed sand as heat carrier and it might provide thermal treatment like calcination during combustion operations. To replace sand by fly ash, however, fly ash is too fine particle so it should be aggregated to bigger particles in order to comply with physical requirements of heat carrier in fluidized bed combustors. Therefore, geocasting might be a promising solution for both fly ash application and fly ash thermal treatment. Materials used in this study are fluidized bed type MSWI fly ash, potassium silicate and potassium hydroxide. Geopolymer slurry was produced using 15M KOH solution, which should be used 24 hours after the solution curing. Then KOH solution was mixed with potassium silicate and distilled water in a mixer (200 rpm, 20 min) according to the following weight ratio: KOH (15 M): potassium silicate: H₂O = 1:2: 0.5. In this study, the authors added 20 g of KOH solution, 40 g of potassium silicate and 10 g of distilled water. Fly ash was added to this solution with equal amount to 15 M KOH solution. They were stirred at 200 rpm for 30 min at room temperature. Accelerating geopolimerzation reaction, geopolymer slurry was placed into an oven at 80 °C for 2 hours. After geopolymer foam was casted, some samples were calcined at 600 °C for 4 hours to simulate similar situation in a fluidized bed combustor. After sample treatments, raw fly ash, geocasted fly ash and geocasted-calcinated fly ash were analyzed by scanning electron microscopy with energy dispersive X-ray spectrometry (SEM-EDX). From SEM observations, raw fly ash mainly consisted of Al, Na, Ca and Cl. They showed sphere particles with smooth surface. On the other hand, geo casted fly ash consisted of more Si and K than raw fly ash. Geocasted fly ash also showed porous characteristic and irregular shape than raw fly ash. Lastly, geocasted-calcinated fly ash consisted of similar elements with geocasted fly ash particles. After calcination, however, porous characteristic disappeared. These results imply that geocasting makes porous particle and following calcination might melt the surface and degrade porous structure. Further research is necessary to check physical stability of goecasted fly ash and toxic element immobilization after geocasting and calcination.

Surface and thermal properties of geocasted municipal solid waste incineration fly ash composites

( Giun Jo ),( Mengzhu Song ),( Patcharanat Kaewmee ),( Astryd Viandila Dahlan ),( Fumitake Takahashi ) 한국폐기물자원순환학회(구 한국폐기물학회) 2019 한국폐기물자원순환학회 심포지움 Vol.2019 No.1

Municipal solid waste (MSW) generation is rapidly increasing in many developing countries owing to population and economic growths. Therefore, reducing MSW is a major issue in the world. In Japan, the incineration is one of the major treatments for reducing MSW volume and weight. Specially, MSWI ashes, which are bottom ash and fly ash, have great potential for recycling in various field such as construction. However, fly ash contains heavy metals like Pb and Zn. Therefore, it might cause environment pollution when they are recycled without any treatment. Chelate treatment for immobilizing hazardous heavy metals in fly ash has possibility of chemical/biological decomposition of chelate-metal complex and might cause long-term high concentration of organic hydrocarbons in landfill site as well as leaching of heavy metals to the environment. In this research, the authors targeted fluidized-bed incinerator fly ash. Fluidized-bed incinerators produce only fly ash and its application is strongly requested in Japan. To replace sand by fly ash, aggregating was required to adjust appropriate particle size in order to comply with physical requirements of heat carrier in fluidized bed combustors. This research utilized geocasting method to create sand-alternative heat carrier using fly ash. When fly ash are recycled as heat carrier, thermal treatment of fly ash is also expected for further immobilization of heavy metals contained in fly ash. In this research, the authors measured surface morphology by scanning electron microscope (SEM), heavy metal leachabilities by leaching tests, surface area by nitrogen adsorption based on Brunauer-Emmett-Teller model (BET), and thermal stability by thermogravimetric analysis. The results demonstrated geopolymer by calcined condition effects improved heavy metal immobilization value, and porous characteristic and heavy metal immobilization were influenced by high temperatures.

Short-Selling on Corporate Investment: Korean Evidence

Sang-Giun Yim People&Global Business Association 2023 Global Business and Finance Review Vol.28 No.7

Purpose: Prior studies suggest that an informative stock price helps corporate investment decisions. Since short-selling improves the informativeness of stock prices, short-selling could influence corporate investment. This study examines this conjecture. Design/methodology/approach: Using KOSPI-listed firm data, this study examines whether short-selling affects quantitative aspects, that is, amount, and qualitative aspects, that is, risks and profitability, of R&D or capital expenditure. Findings: The results show a distinct contrast between the two types of investment. After short-selling, a decrease in R&D investment i s observed; however, capital e xpenditure i ncreases i n firms that i nvest much i n capital expenditure. A post-short-selling increase in R&D increases firm risk, but capital expenditure does not. Post-shortselling R&D investment is tied to long-term profitability; however, except for large firms, capital expenditure does not contribute to the increase in long-term profitability. Research limitations/implications: This study provides supporting evidence that improved informativeness of stock prices improves investment efficiency, not only through R&D investment but also through capital expenditure. However, by examining the topic in the big picture, this study leaves out the influence of several factors that can affect investment decisions. Originality/value: This is one of the rare studies that examines the real impact of short-selling.

남극 북 빅토리아 랜드 윌슨 터레인을 구성하는 화성암류의 마그마 기원과 화성활동

한기운(Giun Han),이승구(Seunggu Lee),김윤섭(Yoonsup Kim) 대한지질학회 2018 대한지질학회 학술대회 Vol.2018 No.10

Microstructure Evolution of Al-1% Si Bonding Wire for Microelectronic Reliability

Hyung Giun Kim,Dae Hyung Cho,Eun Kyun Jeong,Won Yong Kim,Sung Hwan Lim 대한금속재료학회 ( 구 대한금속학회 ) 2009 ELECTRONIC MATERIALS LETTERS Vol.5 No.3

In order to determine the reliability of Al-1% Si bonding wires, the microstructure of an annealed wire, including grain morphology and secondary phases, was investigated by conventional transmission electron microscopy (TEM) and high-resolution electron microscopy (HREM). The grains are extremely long and thin parallel to the drawn direction, and the average grain size is about 600 nm to 700 nm. Nano-sized thin plate-like Si crystals of about 10 nm length and a few monolayers thickness were observed, and their crystallography and morphology are discussed in this paper.

The Pricing of Accruals Quality with Expected Returns: Vector Autoregression Return Decomposition Approach

Sang-Giun YIM 한국유통과학회 2020 The Journal of Industrial Distribution & Business( Vol.11 No.3

Purpose: This study reexamines the test on the pricing of accruals quality. Theory suggests that information risk is a priced risk factor. Using accruals quality as the proxy for information risk, researchers have tested the pricing of information risk. The results are inconsistent potentially because of the information shock in the realized returns that are used as the proxy for expected returns. Based on this argument, this study revisits this issue excluding information-shock-free measure of expected returns. Research design, data and methodology: This study estimates expected returns using the vector autoregression model. This method extracts information shocks more thoroughly than the methods in prior studies; therefore, the concern regarding information shock is minimized. As risk premiums are larger in recession periods than in expansion periods, recession and expansion subsamples were used to confirm the robustness of the main findings. For the pricing test, this study uses twostage cross-sectional regression. Results: Empirical results find evidence that accruals quality is a priced risk factor. Furthermore, this study finds that the pricing of accruals quality is observed only in recession periods. Conclusions: This study supports the argument that accruals quality, as well as the pricing of information risk, is a priced risk factor.

Neuroprotective Effect of Aqueous Extract of Polygala tenuifolia Willdenow on Nitric Oxide-induced Apoptosis in SK-N-MC Cells

Young-Giun Kim,Yun-Kyung Song,Hyung-Ho Lim 대한한의학회 2010 대한한의학회지 Vol.31 No.3

Cloning and Characterization of Novel Soluble Acid Invertase Which is Responsible to JA, ABA and GA During Tip Growth of Pea Seedlings (Pisum sativum)

( Dong Giun Kim ),( Jie Sheng Zhang ) 한국환경생물학회 2009 환경생물 : 환경생물학회지 Vol.27 No.4

The enzyme invertase contributes to sugar unloading, pathogen defense, differentiation and development in plants. We cloned the complete cDNA of a soluble acid invertase from pea seedlings (Pisum sativum) via RT-PCR and the rapid amplification of the cDNA end (RACE) technique. The full-length cDNA of the soluble pea invertase comprised 2237 bp and contained a complete open reading frame encoding 647 amino acids. The deduced amino acid sequence showed high homology to soluble acid invertases from various plants. Northern blot analysis demonstrated the soluble acid invertase gene of P. sativum was strongly expressed in sink organs such as shoot tips and root tips, and induced by abscisic acid, gibberellic acid and jasmonic acid in shoots. Especially, gibberellic acid enhanced the gene expression of the soluble acid invertase in a time-dependent manner. This study presents that the gene expression patterns of a soluble acid invertase from pea are strongly consistent with the suggestion that individual invertase gene product has different functions in the growing plant.

사용자의 데이터 웨어하우스 접근과 활용을 위한 메타데이터 관리 사례

김기운(Giun Kim) 한국컴퓨터정보학회 2007 韓國컴퓨터情報學會論文誌 Vol.12 No.5

본 연구는 데이터 웨어하우스 환경에서 어떤 메타데이터를 어떻게 관리하는 가를 알아보기 위하여, 데이터 웨어하우징을 위한 3 가지 메타데이터 관리 스키마(추출 메타데이터, 웨어하우스 메타메이터, 사용자 접근 메타데이터)를 이용한다. 특히, 3 가지 메타데이터 중에서 사용자의 데이터 웨어하우스에 대한 접근과 그 활용을 위한 웨어하우스메타데이터와 사용자 접근 메타데이터에 초점을 두고 이들 메타데이터 관리에 대한 사례를 연구한다. This paper uses the taxonomy of 3 metadata schema(extraction metadata, warehouse metadata, and user access metadata) to investigate how to manage metadata and what metadata to manage in data warehouse. In particular, this paper focuses on two kinds of metadata(warehouse metadata and user access metadata) and studies a case about metadata management in a real business world

Algorithm/Architecture Co-Exploration of Visual Computing on Emergent Platforms: Overview and Future Prospects

Gwo Giun Lee,Yen-Kuang Chen,Mattavelli, M.,Jang, E.S. IEEE 2009 IEEE transactions on circuits and systems for vide Vol.19 No.11

<P>Concurrently exploring both algorithmic and architectural optimizations is a new design paradigm. This survey paper addresses the latest research and future perspectives on the simultaneous development of video coding, processing, and computing algorithms with emerging platforms that have multiple cores and reconfigurable architecture. As the algorithms in forthcoming visual systems become increasingly complex, many applications must have different profiles with different levels of performance. Hence, with expectations that the visual experience in the future will become continuously better, it is critical that advanced platforms provide higher performance, better flexibility, and lower power consumption. To achieve these goals, algorithm and architecture co-design is significant for characterizing the algorithmic complexity used to optimize targeted architecture. This paper shows that seamless weaving of the development of previously autonomous visual computing algorithms and multicore or reconfigurable architectures will unavoidably become the leading trend in the future of video technology.</P>