• Title/Summary/Keyword: Drying techniques

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Interpretation of Material Homogenity and Making Techniques of the Jar Coffins from the Oryangdong Kiln Site and the Ungokdong Tomb Site in Naju, Korea (나주 오량동 가마와 운곡동 분묘 유적 출토 대형전용옹관의 재료학적 동질성과 제작기법 해석)

  • Kim, Ran-Hee;Cho, Mi-Soon;Yeon, Ung;Seo, Jeong-Seog;Lee, Chan-Hee
    • Journal of Conservation Science
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    • v.26 no.3
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    • pp.229-245
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    • 2010
  • The pupose of this study was to identify the material characteristics, firing environments and making techniques for the jar coffins from the Oryangdong kiln site and the Ungokdong tomb site in Naju. All jar coffins had very similar physical, mineralogical and geochemical characteristics, although it was excavated from the different sites. The wall thickness of the jar coffins was about 2.3 to 5.3 cm. Under the microscopy, the jar coffins include a large quantity of various quartz with some microcrystalline and showed partly orthoclase and biotite. It is presumed that the mineral sherds added to maintain the thick wall and to control the percentage of contraction during drying and firing of jar coffins and it has contained about 11.4 to 19.8 %. Firing temperature of the jar coffins is estimated as 1,000 to $1,150^{\circ}C$. Also, all jar coffins and soils show similar geochemical behavior of elements and clay-mineralization degree within the site. This indicates making that the soil is probable to be a raw material of the jar coffins. But it shows different characteristics in major elements of soils which is collected at the kiln floor and the trench region of the Oryangdong kiln site because of the lack of quartz and feldspar in the soils. Therefore, it can use of the jar coffins making clay, if it goes through a simple special process such as mixing temper.

Ion beam irradiation for surface modification of alignment layers in liquid crystal displays (액정 디스플레이 배향막을 위한 이온빔 표면조사에 관한 연구)

  • Oh, Byeong-Yun;Kim, Byoung-Yong;Lee, Kang-Min;Kim, Young-Hwan;Han, Jeong-Min;Lee, Sang-Keuk;Seo, Dae-Shik
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2008.04a
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    • pp.41-41
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    • 2008
  • In general, polyimides (PIs) are used in alignment layers in liquid crystal displays (LCDs). The rubbing alignment technique has been widely used to align the LC molecules on the PI layer. Although this method is suitable for mass production of LCDs because of its simple process and high productivity, it has certain limitations. A rubbed PI surface includes debris left by the cloth, and the generation of electrostatic charges during the rubbing induces local defects, streaks, and a grating-like wavy surface due to nonuniform microgrooves that degrade the display resolution of computer displays and digital television. Additional washing and drying to remove the debris, and overwriting for multi-domain formation to improve the electro-optical characteristics such as the wide viewing angle, reduce the cost-effectiveness of the process. Therefore, an alternative to non-rubbing techniques without changing the LC alignment layer (i.e, PI) is proposed. The surface of LC alignment layers as a function of the ion beam (IE) energy was modified. Various pretilt angles were created on the IB-irradiated PI surfaces. After IB irradiation, the Ar ions did not change the morphology of the PI surface, indicating that the pretilt angle was not due to microgrooves. To verify the compositional behavior for the LC alignment, the chemical bonding states of the ill-irradiated PI surfaces were analyzed in detail by XPS. The chemical structure analysis showed that ability of LCs to align was due to the preferential orientation of the carbon network, which was caused by the breaking of C=O double bonds in the imide ring, parallel to the incident 18 direction. The potential of non-rubbing technology for fabricating display devices was further conformed by achieving the superior electro-optical characteristics, compared to rubbed PI.

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Assessment for the Possibility of Water-ecosystem Restoration Applying LID Techniques in the Deokjin Park Area, Jeonju City (LID기법을 이용한 전주 덕진공원의 수생태 복원 가능성 평가)

  • Choi, Seung-Hyun;Kim, Seok-Hwi;Kim, Kangjoo
    • Economic and Environmental Geology
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    • v.48 no.6
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    • pp.477-490
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    • 2015
  • In this study, we investigated the restoration possibility of the old streams by enhancing the rainwater infiltration in the watershed of Deokjin Park, Jeonju City. This study was performed by modeling groundwater discharge to the streams under various conditions. We assessed the amount and location of groundwater recharge enhancement to restore the streams and evaluated whether the baseflows of the restored streams are sufficient to keep the water ecosystem of the Deokjin Pond. The results show that the baseflow of the streams can persist for a longer time even during the dry season when the rainwater drainage system is recovered similarly to the those before development using low impact development (LID) techniques. The enhancements of recharge in the headwater area, which is the area around the zoo and Daeji Village in the Deokjin Park watershed, is useful to increase the baseflows of the downstream reaches. Furthermore, spreaded recharge over a widespread area is better to prevent the streams from drying than the intensive recharge at a few sites.

An Archaeological Review of the Inscribed Bricks Excavated from the Tomb of Jang Mui: A Focus on the Collection of the National Museum of Korea (장무이묘 출토 명문전(銘文塼)의 고고학적 검토 -국립중앙박물관 소장품을 중심으로)

  • Lee Nakyung
    • Bangmulgwan gwa yeongu (The National Museum of Korea Journal)
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    • v.1
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    • pp.36-73
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    • 2024
  • The Tomb of Jang Mui located in Bongsan-gun, Hwanghae-do Province has attracted much attention since its first investigation due to the inscribed bricks found there that have allowed the guessing of the name and official title of its occupant and construction date. Inscriptions on these bricks, such as the "Prefect of Daebang Commandery Jang Mui" and the "Mu" (戊, the fifth sign of the Chinese calendar), and "Sin" (申, the ninth sign of the Chinese zodiac), have become the basis for believing the location of the government office of Daebang Commandery to be in Bongsangun, Hwanghae-do Province rather than somewhere in the Hangang River region. From the early days of its investigation, the tomb was suggested as historic remains of the Daebang Commandery along with the Earthen Fortress in Jitap-ri. Inscribed bricks excavated from the Tomb of Jang Mui were featured in several books and articles in the form of photographs and rubbings, leading to a vast body of studies on its construction period and the characteristics of its occupant that drew upon interpretations of the inscriptions. However, the inscribed bricks themselves were not publicly available outside those held in the collection of the University of Tokyo, making it difficult to expect consistent research findings on the types of inscribed bricks and their contents. Following previous studies re-examining the structure of the tomb and the materials used for its construction, most scholars dated the Tomb of Jang Mui to 348, a period after the collapse of Daebang Commandery. However, there is still a lack of adequate examination of the bricks, which account for the majority of the artifacts excavated from the tomb. Among the bricks excavated from most brick chamber tombs, including the Tomb of Jang Mui, only those with inscriptions or designs have been collected. Moreover, among these, only those with inscriptions or designs on the stretcher faces have been documented. Accordingly, the bricks themselves have been notably understudied. This paper intends to reorganize the contents of the inscriptions on eleven types (out of sixty-one pieces) of bricks in the collection of the National Museum of Korea, which make up the majority of the bricks excavated from the Tomb of Jang Mui. It also classified them according to their shapes. Furthermore, it examined the bricks from the Tomb of Jang Mui as architectural materials by focusing on their production techniques, including their forming, drying, and firing. Taking a more specific approach, it then compared the results to other bricks from the second century through the fourth century: those from the brick chamber tombs of the Nangnang and Daebang Commanderies and those from the brick chamber tombs built after Nangnang and Daebang Commanderies were ousted. The examination of bricks from the Tomb of Jang Mui has revealed that these bricks were basically produced using the brick manufacturing techniques of Nangnang, but they incorporated new elements found in bricks from brick chamber tombs or brick-and-stone chamber tombs constructed around the mid-fourth century in terms of their size, the use of lime, and the number of inscribed bricks. This supports the prevailing view that the date of the construction of the Tomb of Jang Mui is 348. The Tomb of Jang Mui sustained the existing brick chamber tomb burial tradition, but its ceiling was finished with stone. It demonstrates a blending of the brick chamber tomb practice of the Nangnang and Daebang Commanderies by using bricks produced based on related techniques, but with new elements such as the addition of a lime layer to the bricks. This fusion reflects the political circumstances of its time, such as the expulsion of the Daebang Commandery and the advance of the Goguryeo Kingdom, leading to diverse interpretations. Given archaeological evidence such as the structure, materials, and location of the tomb, the Tomb of Jang Mui appears to be highly related to the Goguryeo Kingdom. However, the forms of the inscribed bricks and the contents of the inscriptions share similarities with brick chamber tombs constructed during the third and fourth centuries in the Jiangsu and Zhejiang regions in China. Further studies on whether the use of lime was an influence from Goguryeo or a continuation of the Daebang tradition and a comparative examination with contemporaneous stone ceiling tombs will provide a more refined understanding of the Tomb of Jang Mui.

Ultra Dry-Cleaning Technology Using Supercritical Carbon Dioxide (초임계 이산화탄소를 이용한 초순수 건식 세정기술)

  • Joung, Scung Nam;Kim, Sun Young;Yoo, Ki-Pung
    • Clean Technology
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    • v.7 no.1
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    • pp.13-25
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    • 2001
  • With fast advancement of fine machineries and semiconductor industries in recent decades, the ultra-cleaning of organic chemicals, submicron particles from contaminated unit equipments and products such as silicon wafers becomes one of the most important steps for further advancement of such industries. To date, two kinds of ultra cleaning techniques are used; one is the wet-cleaning and the other is the dry cleaning. In case of wet cleaning, removal of organic contaminants and submicron particles is made by DIW with additives such as $H_2O_2$, $H_2SO_4$, HCl, $NH_4OH$ and HF, etc. While the wet cleaning method is most widely adopted for various occasions, it is inevitable to discharge significant amount of toxic waste waters in environment. Dry cleaning is an alternative method to mitigate environmental pollution of the wet cleaning with maintaining comparable degree of cleaning to the wet cleaning. Although there are various concept of dry cleaning have been devised, the dry cleaning with environmentally-benign solvent such as carbon dioxide proven to show high degree of cleaning from the contaminated porous surface as well as from the bare surface. Thus, special global attention has been placing on this technique since it has important advantages of simple process schemes and no environmentally concern, etc. Thus, this article critically reviews the state-of-the-art of the supercritical fluid drying with emphasis on the thermo-physical characteristics of the supercritical solvent, environmental gains compared to other dry cleaning methods, and the generic aspects of the basic design and processing engineering.

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Properties of Eco-Construction Material Using Recycled Sewage Sludge Ash (하수슬러지 소각재를 재활용한 친환경 건설 소재의 재료적 특성)

  • Jo, Byung-Wan;Lee, Jea-Ik;Park, Seung-Kook;Lee, Jae-Seung
    • Journal of the Korea Concrete Institute
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    • v.19 no.6
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    • pp.667-676
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    • 2007
  • As the 21st century began, cement and concrete that are representatives of modem building materials became a major factor in global warming, air pollution and environmental pollution. Also, the problems that are generated while pursuing high performance and high strength became social issues. Therefore, it has become urgent to prepare counter plans. This study has aimed at the recycling of sewage sludge ash and developing it as a new concept in building material which serves the environmental considerations for long-lasting developmental purpose. Also, the study aimed to find a substitute for scarce natural resources and to secure high techniques for waste recycling. The purpose of this study was also to solve fundamentally secondary environmental pollution. The results revealed that the chemical components of sewage sludge ash are mainly $SiO_2\;and\;Al_2O_3$ which are similar to the components of pozzolan. Also, it was identified that sewage sludge ash can be utilized as a hardened specimen with an alkali activated pozzolan reaction. Considering the possibility of appropriate strength development and the advantage of drying shrinkage, compared with that of cement, it was believed that sewage sludge ash can demonstrate a function as a substitute for cement given.

Determination of Optimized Growth Medium and Cryoprotective Additives to Enhance the Growth and Survival of Lactobacillus salivarius

  • Yeo, Soyoung;Shin, Hee Sung;Lee, Hye Won;Hong, Doseon;Park, Hyunjoon;Holzapfel, Wilhelm;Kim, Eun Bae;Huh, Chul Sung
    • Journal of Microbiology and Biotechnology
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    • v.28 no.5
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    • pp.718-731
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    • 2018
  • The beneficial effects of lactic acid bacteria (LAB) have been intensively investigated in recent decades with special focus on modulation of the host intestinal microbiota. Numerous discoveries of effective probiotics are driven by a significantly increasing demand for dietary supplements. Consequently, technological advances in the large-scale production and lyophilization are needed by probiotic-related industries for producing probiotic LAB for commercial use. Our study had a dual objective, to determine the optimum growth medium composition and to investigate appropriate cryoprotective additives (CPAs) for Lactobacillus salivarius, and compare its responses with other Lactobacillus species. The one-factor-at-a-time method and central composite design were applied to determine the optimal medium composition for L. salivarius cultivation. The following composition of the medium was established (per liter): 21.64 g maltose, 85 g yeast extract, 1.21 ml Tween 80, 6 g sodium acetate, $0.2g\;MgSO_4{\cdot}7H_2O$, $0.02g\;MnSO_4{\cdot}H_2O$, $1g\;K_2HPO_4$, $1.5g\;KH_2PO_4$, $0.01g\;FeSO_4{\cdot}7H_2O$, and 1 g sodium citrate. A cryoprotective additive combination comprising 10% (w/v) skim milk and 10% (w/v) sucrose supplemented with 2.5% (w/v) sodium glutamate was selected for L. salivarius, and its effectiveness was confirmed using culture-independent methods in the freeze-dried cells of the Lactobacillus strains. In conclusion, the optimized medium enhanced the species-specific cultivation of L. salivarius. On the other hand, the cryoprotective effects of the selected CPA mixture may also be dependent on the bacterial strain. This study highlights the necessity for precise and advanced processing techniques for large-scale production of probiotics in the food and feed industries.

Comparison Study on the Material Characteristics of Oil Paints (I) (유화물감의 재질적 특성 비교 연구 (I))

  • Kim, Jung Heum;Park, Hye Sun;Lim, Sung Jin
    • Journal of Conservation Science
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    • v.33 no.2
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    • pp.85-95
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    • 2017
  • Oil paints are mixtures of pigments, drying oils and additives. In the past, oil paints were mainly composed of inorganic pigments. However, recently color matching techniques vary depending on manufacturers due to the development of various kinds of synthetic pigments. Despite this, most studies of oil paints in South Korea are about durability tests, and there is no comparative study on the characteristics of commercial oil paint components. This study aims to compare the properties of four different kinds of oil paints from four manufacturers, which are the most popularity used. Extender pigments in oil paint from C brand differed from that of other manufacturers and various kinds of coloring pigments were differently used depending on the oil paints and the manufacturers. The mixing ratios and the pigment types differed even for oil paints having the same product name. It is assumed that these differences could affect the colors. The result of this study is expected to contribute to the analysis of artworks through the accumulation of scientific data of oil paints. In addition, it can be utilized as a scientific basis for art history studies, including the characteristics of artists or production year.

Evaluation of Surface Moisture Content of Liriodendron tulipifera Wood in the Hygroscopic Range Using NIR Spectroscopy (근적외선 분광분석법을 이용한 백합나무 목재의 섬유포화점 이하 표면함수율 평가)

  • Eom, Chang-Deuk;Han, Yeon-Jung;Chang, Yoon-Sung;Park, Jun-Ho;Choi, Joon-Weon;Choi, In-Gyu;Yeo, Hwan-Myeong
    • Journal of the Korean Wood Science and Technology
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    • v.38 no.6
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    • pp.526-531
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    • 2010
  • For efficient use of wood, it is important to control moisture of wood in processing wood. Near-infrared (NIR) spectroscopy can be used to estimate the physical and chemical properties of materials quickly and nondestructively. In this study, it was intended to measure the moisture contents on the surface of wood using NIR spectroscopy coupled with multivariate analytic statistical techniques. Because NIR spectroscopy is affected by the chemical components of the specimens and contains signal noise, a regression model for detecting moisture content of wood was established after carrying out several numerical pretreatments such as Smoothing, Derivative and Normalization in this study. It shows that the regression model using NIR absorbance in the range of 750~2,500 nm predicts the actual surface moisture content very well. Near-infrared spectroscopy technique developed in this study is expected to improve a technology to control moisture content of wood in using and drying process.

Development of small constructed wetland for urban and roadside areas (도시 및 도로 조경공간을 활용한 소규모 인공습지 조성 기술)

  • Kang, Chang-Guk;Maniquiz, Marla C.;Son, Young-Gyu;Cho, Hye-Jin;Kim, Lee-Hyung
    • Journal of Wetlands Research
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    • v.13 no.2
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    • pp.231-242
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    • 2011
  • Recently, the green spaces in the urban areas were greatly reduced due to urbanization and industrialization. As urban structures such as roads and buildings are built, the amount of impervious area within a watershed increases. High impervious surfaces are the common causes of high runoff volumes as the soil infiltration capacity decreases and the volume and rate of runoff increase thereby decreasing the groundwater recharge. These effects are causing many environmental problems, such as floods and droughts, climate change, heat island phenomenon, drying streams, etc. Most cities attempted to reduce sewer overflows by separating combined sewers, expanding treatment capacity or storage within the sewer system, or by replacing broken or decaying pipes. However, these practices can be enormously expensive than combined sewer overflows. Therefore, in order to improve these practices, alternative methods should be undertaken. A new approach termed as "Low Impact Development (LID)" technology is currently applied in developed countries around the world. The purpose of this study was to effectively manage runoff by adopting the LID techniques. Small Constructed Wetland(Horizontal Subsurface Flow, HSSF) Pilot-scale reactors were made in which monitoring and experiments were performed to investigate the efficiency of the system in removing pollutants from runoff. Based on the results of the Pilot-plant experiments, TSS, $COD_{Cr}$, TN, TP, Total Pb removal efficiency were 95, 82, 35, 91 and 57%, respectively. Most of the pollutants were reduced after passing the settling tank and the vertical filter media. The results of this study can contribute to the conservation of aquatic ecosystems and restoration of natural water cycle in the urban areas.