• Resources Recycling
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• v.28 no.6
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• pp.9-17
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• 2019

The use of rare metals in increasing along with the growth of the Fourth industrials revolution and new energy industries, and the recycling of rare metals becomes more important as the used of rare metals increase. In this paper, the domestic and international quality standards of tin metal, one of the rare metals, and the performance test of recycled tin were investigated. As a results of the performance test, it was analyzed that there is no difference in performance between the natural and recycled tin.

• Journal of Life Science
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• v.11 no.6
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• pp.537-542
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• 2001

The concentrations of ${\gamma}$-aminobutyric acid in some Korean plants and mushrooms were investigated. ${\gamma}$-amino-butyric acid concentrations in Morus alba leaves, Cudrania tricuspidate leaves and fruits were 134.03, 104.13 and 120.99 mg/100g dry matter basis, respectively, ${\gamma}$-aminobutyric acid concentrations in Pleurotus ostreatus, Flammulina velutipes and Auricularia auricula were 93.44, 72.17 and 66.48 mg/100g dry matter basis. respectivley.

• Resources Recycling
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• v.24 no.6
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• pp.17-23
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• 2015

Flue gas desulfurization(FGD) is the technique to remove $SO_2$ gas from stack gases of coal-fired plants. Many researcher have studied to replace the desulfurizing agent because FGD systems use a lot of limestone and energy. In this study, we use the limestone sludge which is a by-product of steel industry in order to replace desulfurizing agent of FGD system by control the particle size of limestone sludge. And desulfurization performance test is implemented by investigating $SO_2$ gas removal properties upon the characteristic of the limestone sludge with various particle size.

• Journal of the Korean Recycled Construction Resources Institute
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• v.2 no.2
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• pp.107-114
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• 2014

The objective of this study is to evaluate the strength development of blast furnace slag concrete in response to the use of recycled aggregate as alkali activator. The influence of the amount of recycled aggregate was evaluated depending on different ratios of replacement for each RFA and RCA to NFA and NCA, respectively. The results indicated that as replacement of RFA and RCA increased, their strength exhibited to be increased. This was due to the fact that the latent hydraulic properties of blast furnace slag was activated by the alkali in recycled aggregates. However, in case of 365-days, it showed lower compressive strength than using NA(natural aggregates) which could be explained as the exhaustively use of alkali containing in RA. The specimens using RA showed about 90% of compressive strength comparing with specimens using NA.

• Resources Recycling
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• v.24 no.1
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• pp.12-20
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• 2015

In this study, change of hydration property with contents and type of gypsum in ternary natural hydraulic lime containing blast furnace slag and gypsum was investigated. Anhydrite, hemihydrate and dihydrate were added 3 % and 10 %, respectively in natural hydraulic lime adding blast furnace slag 20 %. Hydration and physical behavior due to solubility and reactivity of different types of gypsum were analyzed in early hydration. As a result of analysis of hydration properties, in all samples, hydrates such as ettringite and C-S-H were produced in early hydration, and amount of hydrates with increase of hydration time was increased. In the case of compressive strength, when contents of gypsum are 3 %, it was higher compressive strength than other specimens. At hydration 28 days, for addition of anhydrite and hemihydrate, compressive strength was more than adding dihydrate.

• Resources Recycling
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• v.16 no.6
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• pp.20-27
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• 2007

This paper presents a detailed experimental study on the durability properties of mortar matrix made with two kind of recycled fine aggregates(RAA, RAB) and five replacement levels (0, 25, 40, 75 and 100) of the recycled fine aggregates as a partial replacement of natural fine aggregate (NA). The durability properties of mortar matrix was evaluated using compressive strength, chloride ion ingress, sulfate attack and carbonation. The test results indicated that the water absorption and Adhered mortar of the recycled fine aggregate was a major factor controlling durability properties. Hereafter, when using built recycled fine aggregate is expected, appropriate removal Adhered mortar and reasonable replacement ratio of recycled fine aggregates was 25% weight of cement are advised to apply to the concrete materials.

• Bulletin of the Society of Naval Architects of Korea
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• v.32 no.4
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• pp.57-63
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• 1995

극지개발을 위해서는 극지의 혹독한 자연환경을 대상으로 하는 과학지식과 극지에서 사용되는 특수시설과 장비를 설계, 시공 그리고 운용하는 공학기술이 요구된다. 극지관련 공학기술은 저 온용재료 관련기술, 도로나 교량, 건축물과 같은 극한지 천연자원의 시추와 생산, 수송을 위한 해양구조물과 파이프라인 관련기술, 그리고 얼음의 재료특성에 관한 이론 및 실험으로 크게 구 분할 수 있다. (Table 1). 극지용 구조물과 빙해항행선박 (쇄빙선) 은 일반 해역에서 운용되는 구조물에 비해 형상, 구조강도, 의장, 저온특수설비 등에서 새로운 개념의 기술이 요구되기 때 문에 금후 국내 조선해양산업계가 지향해야 할 고도의 기술집약형 건조물이다. 또한 최근 들어 국내에서도 시베리아 천연자원의 해상운송을 위해 빙해역을 운항할 수 있는 유조선이나 일반 화물선을 확보해야할 필요성이 대두되고 있으며, 또한 국내 조선업계의 생산기술이 비약적으로 발전함에 따라 외국으로부터의 빙해항행선박의 수주도 이루어지고 있으나 아직 이들 선박의 설계를 위한 독자적인 기술은 미흡한 현실이다. 극지개발은 이론적 접근과 함께 실험에 의한 신뢰성 있는 자료를 축적해야 한다. 이를 위해서는 빙해수조(,ice model basin)의 건조나 빙역학 실험을 위한 냉동실험실 (cold room)의 건립을 위한 초기투자가 절실히 요구되며 산업계의 수 요에 따른 포괄적인 산학협동연구가 진행되어야 할 필요가 있다. 빙해수조와 냉동실험실은 빙 해역에 직접 접하지 않은 국가에서 극지공학 연구에 참여하기 위한 필수적인 시설인데 table 2에 대표적인 빙해수조의 설치장소와 규모에 대하여 정리하였다. 이 글은 우리 나라가 쉽게 접할 수 없는 극지환경을 이해하고 가까운 장래에 예상되는 수주경쟁에 대비하여, 국내외의 극지개발 동향을 분석하고 이에 대한 국내의 극지관련 연구의 현황과 앞으로의 전망을 살펴보기 위하여 준비된 것이다. 이 글에서는 극지공학 일반보다는 조선해양분야에 관련된 내용만으로 국한한다.

• Journal of the Korean Recycled Construction Resources Institute
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• v.11 no.4
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• pp.542-551
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• 2023

In this paper, the thermal properties of porous concrete containing natural fine aggregates in bottom ash aggregates were analyzed. In this study, natural fine aggregates were used for bottom ash aggregates to understand the material properties of each aggregate and then used as an aggregate for porous concrete. A porous concrete specimen was manufactured by fixing the water-binder ratio at 0.25 and designating the compaction at 0.5, 1.5, and 2.5 MPa. Unit weight, total void ratio and thermal conductivity test were measured and discussed. As the compaction increased and the mixing ratio of natural fine aggregates increased, the unit weight and thermal conductivity increased, and the total void ratio decreased. In addition, the correlations between unit weight, total void ratio and thermal conductivity of porous concrete with previous experimental data were presented and the correlation coefficient (R²) was also analyzed.

• Journal of Life Science
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• v.32 no.8
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• pp.601-610
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• 2022

P. tenebrifer (PT) belongs to the Diptera order and Stratiomyidae family. Recently, insect industry have been focused as food, animal feed and environmental advantages. γ-aminobutyric acid (GABA) and melatonin have been associated with regulating sleep and depression. GABA is the primary inhibitory neurotransmitter and is synthesized via biotransformation of monosodium glutamate (MSG) to GABA by lactic acid bacteria. In this study, we first used a GABA-enhanced PT extract, wherein GABA was enhanced by feeding MSG to PT. The underlying mechanisms preventing stress and insomnia were investigated in a corticosterone (CORT)-induced endoplasmic reticulum (ER) stress and chronic restraint stress (CRS)-exposed mouse model, as well as in pentobarbital (45 mg/kg)-induced sleep behaviors in mice. In the present study, the GABA peak was detected in high-performance liquid chromatography-evaporative light scattering detector (HPLC-ELSD) analysis and showed in Ptecticus tenebrifer water extract (PTW) but not in non-PTW extract. The results showed that PTW and Ptecticus tenebrifer with 70% ethanol extract (PTE) exerted neuroprotective effects by protecting against CORT-induced downregulation of phosphorylated extracellular signal-regulated kinase 1/2 (ERK1/2) and cAMP-response element binding protein (CREB) expression. In addition, PTW (300 mg/kg) significantly reduced CORT levels in CRS-exposed mice. Furthermore, PTW (100 and 300 mg/kg) significantly reduced sleep latency and increased total sleep duration in pentobarbital (45 mg/kg)-induced sleeping behaviors, which was related to serum melatonin levels. In conclusion, our results suggest that PTW exerts anti-stress and sleep-enhancing effects by regulating serum CORT and melatonin levels.

• Economic and Environmental Geology
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• v.48 no.1
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• pp.89-101
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• 2015

The sour gas is natural gas containing components such as hydrogen sulphide and carbon dioxide that form acids when mixed with water. Element sulfur precipitates from sour gas when reservoir pressure and temperature decrease. According to the International Energy Agency, about 43% of the world's natural gas reserves(2,580 tcf or 73.057 tcm), excluding North America, are sour. The sour gas is often derived from the Germanic word 'sauer or acidic' and the etymology referred to as 'sour'. Sour gas requires special handling and infrastructure because it contains significant amounts of hydrogen sulphide, making it highly corrosive, flammable and explosive, and there fore more costly and dangerous to process. So the business of sour gas is affected by two important factors: the economic value of the gas, and the methods used in its production. According to be analyzed in the academic literature to sour gas(2000~2014) by the program of 'web of science', the research activities 145 papers in sour gas.