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        검색결과 200

        161.
        2018.10 서비스 종료(열람 제한)
        Various treatment modalities for vocal process granuloma include simple observation, antireflux therapy, voice therapy, botulinum injection, and steroid inhalation, but recurrence rates are high. Surgical excision can be considered in refractory and recurrent cases. In this study, the authors report the effectiveness of surgical excision using a carbon-dioxide laser with topical Mitomycin-C for the treatment of recurrent vocal process granuloma. The study included 28 patients with recurrent vocal process granuloma despite various treatments. The vocal process granuloma was excised using a carbon-dioxide laser and 1 cc of 0.4 mg/mL topical Mitomycin-C was applied for 4 minutes. Follow-up duration was 13-33 months (mean, 21.8 months). Of 28 patients, 19 (67.9%) were cured. Two who received surgical excision as a first-line treatment, 2 who used a steroid inhaler as a first-line treatment, and 5 who previously took antireflux medication as initial treatment showed recurrence. Surgical excision using a carbon-dioxide laser with topical application of Mitomycin-C is considered effective for recurrent vocal process granuloma.
        162.
        2018.07 KCI 등재 서비스 종료(열람 제한)
        This study assesses greenhouse gas evolution from construction-material manufacturing facilities and estimates the potential reduction of these gases via the future massive sequestration of carbon dioxide. The scope of the evaluation specifically targets the global-warming potential in terms of kg-CO2 equivalent/tonnage industrial waste. Life cycle assessment (LCA) is a method to quantitatively analyze the input and output of a specific material resource during its life cycle from raw-material acquisition to final disposal as well as its environmental effect(s). LCA comprises four steps: its objective and definition of the scope, the entire life-cycle analysis list, an evaluation of its effects, and life-cycle analysis. The annual inflow of petro-ash reaches 300,000 tons, and this material is transported via screw-driving systems. The composition of the petro-ash is 1.2% volatile compounds, 6.8% fixed carbon and 92% ash contents. A total of 38,181,891 Nm3/yr of carbon dioxide is sequestrated, which is equivalent to 75,000 tons per annum and 304.5 kg/ton of petro-ash waste, with 250 kg/ton of the latter sequestrated as calcium carbonate. The final analysis on the effect of one ton of petro ash in construction materials showed 27.6 kg-CO2 eq emission. According to the final LCA analysis, only 27.6 kg-CO2 eq/ton was emitted by the petro-ash that was used in construction materials if CO2 fixation during carbonate mineralization was considered, where -250 kg-CO2 eq/ton positively contributed to the LCA. In the future, commercial-scale process modification via the realization of continuous processes and the more efficient reduction of carbon dioxide is anticipated.
        163.
        2017.11 서비스 종료(열람 제한)
        In this research, carbon dioxide is captured and chemically converted to high purity calcium carbonate salt which can be used for various industrial fields. Aqueous indirect inorganic carbonation methods were applied throughout the research and seawater-based industrial wastewater was utilized for metal ion supply. For CO2 capture, representative alkanolamine absorbent solutions in 30 wt% concentration were used, that is, monoethanolamine (MEA), diethanolamine (DEA), and methyldiethanolamine (MDEA). For high purity metal ion separation, calcium ion contained in the seawater-based industrial waster was separated in the form of gypsum followed by the carbonation reaction to form high purity calcium carbonate salt. Consiering the final products and their economic cost, the cycle using MEA will be proper. However, if MDEA can be used, the amount of carbon dioxide capture capacity per cycle would be great. Also, conceptual continuous cycle which produces calcium carbonate and magnesium carbonate was suggested. This research may help the nations such as European nations or east asian countries like Korea and Japan where no adequate CO2 storages exist and crust activities are in progress, if commercialized.
        164.
        2017.10 KCI 등재 서비스 종료(열람 제한)
        In this study, alkali-activated slag (AAS) concrete made with blast furnace slag (BFS) was investigated as a replacement for ordinary Portland cement (OPC) concrete for changes in the compressive strength before and after CO2 exposure and chemical reactions with CO2. Before CO2 exposure, the compressive strength of AAS concrete was found to be up to 21 MPa, which was higher than that of OPC concrete. Exposing AAS concrete to CO2 at 5,000 ppm for 28 days did not significantly change the compressive strength. In contrast, the compressive strength of OPC concrete decreased by 13% in the same conditions. In addition, AAS concrete had the highest CO2 capture capacity of greater than 50 g CO2/kg, while the CO2 capture capacity of OPC concrete was only 2.5 g CO2/kg. Rietveld analyses using XRD results showed that fractions of main calcium-silicate-hydration (C-S-H) gels on the surface of AAS concrete did not significantly drop after CO2 exposure; the C-S-H gel on the AAS concrete was continuously produced by reacting with the SiO2 produced after the reaction with CO2 and Ca(OH)2 inside the concrete, with the result that the compressive strength of AAS concrete did not change after CO2 exposure. Thus, AAS concrete can be applied to CO2-rich environments as both a stable construction material and a CO2 sequestrate agent.
        165.
        2017.05 서비스 종료(열람 제한)
        전 세계적으로 가금류의 소비가 증가함에 따라, 가금류와 관련된 폐기물 증가해왔다. 이 가금류 관련 폐기물의 지속적으로 처리함과 동시에 에너지 회수를 위하여, 본 연구에서는 이산화탄소 조건하에서 열분해를 진행하였다. 이산화탄소의 영향을 조사하기 위해, 일반적으로 열분해 공정에서 사용되는 질소조건을 기준으로 하여, 열중량 분석, 열분해에서 발생한 가스 및 타르를 분석, 비교하였다. 먼저 열중량 분석은 25℃부터 900℃로 진행하였으며, 분석한 결과에 의하면 650℃까지 물리적인 차이가 없었다. 다음으로 이산화탄소의 화학적인 영향을 조사하기 위해, 열분해(270℃부터 720℃)에서 발생한 주요 가스인 수소, 메탄, 이산화탄소 각각의 농도에 대해 분석하였고, 최종적으로 발생한 타르의 양을 측정하였다. 이산화탄소의 효과로서 일산화탄소가 증가하고 타르발생량이 감소하였다. 이 결과에 의하면, 열분해에서 발생한 VOCs가 이산화탄소 조건에서 더 쉽게 분해되었고, 이에 따라 일산화탄소가 증가한 것으로 보여진다. 본 연구는 잠재적인 지구온난화 가스인 이산화탄소를 이용함으로써 효율적인 에너지회수를 동반한 폐기물을 처리할 수 있는 새로운 방법을 제시한다.
        166.
        2017.05 서비스 종료(열람 제한)
        폐시멘트, 폐콘크리트, 제강 슬래그, 폐수 등을 포함하여 다양한 폐기물들이 여러 산업으로부터 배출되고 있다. 그런데 이러한 폐기물들은 Mg2+ 이온, Ca2+ 이온을 다량 포함하고 있다고 알려져 있다. 폐기물 처리 시 이러한 금속 이온을 활용한다면 MgCO3, CaCO3 등 다른 유용한 물질로 전환시킬 수 있다. 이를 위해 지구온난화를 일으키는 주요 원인으로 알려진 이산화탄소를 사용할 수 있고, 이는 이산화탄소 저감 및 폐기물 처리를 동시에 해결할 수 있을 것으로 보인다. 본 연구에서는 CO2의 용이한 전달을 돕기 위한 습식 흡수제에 대해 제안하고 Henry constant, Diffusivity, 총괄반응속도상수(kov)를 측정하였다. 흡수제는 7 wt% 암모니아, 3 wt% ʟ-Arginine, 1 wt% 부식방지제(Imidazole과 1,2,3-Benzotriazole)를 물에 녹여 제조하였다. 암모니아는 기존에 습식흡수제로 사용되던 MEA보다 저렴한 가격을 가지고 있으며 CO2 흡수 능력 또한 우수하다고 알려져 있다. 최근 아미노산은 우수한 CO2 흡수능력과 친환경적인 특성으로 많은 연구가 진행되고 있으며 두 종류의 부식방지제는 암모니아에 의해 발생할 수 있는 플랜트 장비의 부식을 방지하기 위해 첨가되었다. 303.15 K에서 333.15 K의 온도에서 실험이 진행되었으며 실험 결과와 CO2/N2O analogy를 이용해 각 값을 계산하였다.
        167.
        2016.11 서비스 종료(열람 제한)
        도시생활폐기물소각재(MSWI ash)을 매립하게 되면 장기적으로 중금속이 침출된다. 급속탄산화를 통하여 MSWI ash 내의 중금속을 탄산염 형태로 고정하여, 중장기적으로 침출을 방지할 수 있다. 본 연구에서는 급속 탄산화 방법을 통하여 소각재인 fly ash의 중금속 저감 및 이산화탄소 저감에 대해 수행하였다. NH4OH, NH4SCN, 및Ca(OH)2를 이용하여 test 하였으며, 소각재의 중금속을 탄산화 전, 후를 비교하여 중금속이 침출량을 비교 하였다. 추가적으로 이산화탄소가 fly ash에 포집된 이산화탄소 저감량을 나타내면서 이산화탄소 흡수제의 재사용 가능성을 확인하였다. 흡수제를 재생하는 과정에서 나온 CO32-이온에 의해 탄산화 된 금속염들의 성분 분석을 위해, XRD (X-ray diffraction analyzer(Ultima Ⅳ))를 사용하였다. 그리고 FE-SEM(Field emission scanning electron microscope, JEOL-7800)으로 filtering후 건조시킨 샘플과 fly ash의 표면구조를 촬영하고 비교하였다.
        168.
        2016.11 서비스 종료(열람 제한)
        온실가스인 이산화탄소는 다른 온실가스에 비해 Global Warming Potential(GWP)가 가장 낮지만 배출량이 전체 온실가스 중 88 %의 비중을 차지하고 있다. 많은 국가에서 기후변화에 관심을 가지고 이산화탄소 저감에 대한 연구개발이 활발히 일어나고 있다. 본 연구에서는 암모늄 화합물을 이용하여 이산화탄소를 포집하고 산업폐기물의 금속이온을 이용하여 무기재료인 탄산칼슘을 생성하는 다양한 방법을 소개한다. 탄산칼슘 생성을 위해 칼슘이온이 포함된 탈황석고, 폐시멘트를 이용하였다. 결과에서 이산화탄소 포집 성능 및 최종생성물의 결정구조를 확인하였으며, 이산화탄소 loading 값  는 약 2.0의 값을 가진다. X-Ray Diffraction, Scanning Electron Microscope의 분석을 통하여 탄산칼슘이 생성되었음을 확인하였으며, 결정구조는 Vaterite가 생성됨을 확인할 수 있다. 효과적인 공정을 위하여, 생성물을 생성한 후 용액을 회수하여 재이용할 수 있어 연속적인 공정이 가능하다. 회수된 용액의 재이용의 가능성을 보기위하여 이산화탄소를 재흡수 시키면서 같은 공정을 2cycle씩 진행하여, 연속적인 공정의 잠재성을 확인하였다.
        169.
        2016.10 서비스 종료(열람 제한)
        Background : The effective components of Omija(Schisandra chinensis Bailllon) are lignans (schizandrins and gomisins), and this components were contented mostly in seed part on Omija, which have various physiological functionalities such as anti-cancer, anti-inflammatory, and antioxidant activities. Methods and Results : This study was carried out to determine effective condition(CO2, CO2+ethanol) on extraction using supercritical carbon dioxide extraction (SFE) system and to find interrelation on effective components and antioxidant activity of extracts and residues obtained after extraction. Effective components were analysed lignans and phenolic compounds and antioxidant activirty was determined for DPPH radical scavenging ability on methanol extracts of SFE-extract and SFE-residue. On SFE with ethanol, SFE extract was separated two phase, upper(water phase) and lower(oil phase). SFE-extract showed the highest total lignans content(61.36 mg/g, 72.14 mg/g on lower, 50.58 mg/g on upper) and the lowest total phenolic compounds(6.52 mg/100g) and SFE-residue showed the lowest total lignans content(1.45 mg/g) and the highest total phenolic compounds(16.23 mg/100g) by extracted on CO2+ethanol treatment. SFE-residue methanol extract showed the highest DPPH radical scavenging abilities and SFE-extract upper showed the lowest. Conclusion : Thus, this results showed SFE-extract showed the highest total lignans content, but SFE-residue showed the highest DPPH radical scavenging ability although the lowest total lignans content.
        170.
        2015.12 KCI 등재 서비스 종료(열람 제한)
        This study was conducted to serve as the basis for establishing a standard cultivation, which enhances the alternative utilization of pig manure, a major cause of environmental pollution, by finding a means for reducing greenhouse gas emissions for eco-friendly cultivation. In a laboratory, CH4 and CO2 emission patterns were investigated corresponding to incremental pig manure treatments in paddy soil. The emissions peaked 12 to 27 days after manure application in the 100~400% applications. It was found that increasing applications of pig manure resulted an increase in CH4 and CO2 emissions. Additionally, application of more than 150% emitted a larger amount of these gasses than applying chemical fertilizer. However, the test application of 100% pig manure emitted a smaller amount of CH4 and hence Global Warming Potential (GWP) than those emitted by chemical fertilizer. If appropriate amount of fertilization is applied in compliance with the standard application rate, the pig manure may be effective in reducing greenhouse gas emissions and the soil environment made more favorable than with the use of chemical fertilizer.
        171.
        2015.11 서비스 종료(열람 제한)
        The concentration of carbon dioxide in atmosphere is gradually increasing as industrial activity is being facilitated. Since most of the industries are getting their energy from fossil fuels such as coal, petroleum and gas, carbon dioxide production is inevitable. However, by applying suitable carbon capture process at the end of the carbon dioxide emission facilities, the amount of carbon dioxide emitted to atmosphere can be significantly reduced. Thus, Carbon Capture and Storage (CCS) technologies have been developed by many nations. In that technology, captured carbon dioxide is stored in deep ocean or the underground holes. However, considering environmental effects and geological distinct characteristics, CCS technologies are thought to be developed finding new way to handle captured carbon dioxide. One of the method is to turn captured carbon dioxide into precipitated calcium carbonate salt by adding calcium ions. Conventionally, calcium carbonate salt formation is achieved by reaction under high pressure and temperature. However, this method requires large amount of energy to maintain reaction condition. Hence, carbon dioxide reduction and utilization technology through carbon fixation or carbonation in aqueous phase is proposed in this research. Using aqueous absorbent, carbon dioxide is captured and precipitated calcium carbonate salt was formed by adding calcium ions. All of the reaction occurred under ambient temperature and pressure (1 atm, 298.15 K). The amount of carbon dioxide reduction as well as yield of precipitated calcium carbonate salt were considered. Also, through instrumental analysis including Scanning Electron Microscope (SEM), X‐Ray Diffraction (XRD) and Thermogravimetric Analysis (TGA), possibility of final product utilization was investigated.
        172.
        2015.05 서비스 종료(열람 제한)
        Mineral carbonation, the return technology of Carbon dioxide into the Nature as a generating source, has been studied by advanced countries. Industrial by-products can be used as economical resource for mineral carbonation. This study is intended as an investigation of effluent recycling of liquid carbonation with carbon dioxide fixation using industrial by-products. The nitrogen and carbon dioxide was used by mixing the same as the exhaust gas concentration 15vol%. Carbon dioxide absorbent was used as Mono Ethanol Amine (MEA) concentration of 5~30wt% and then concentration of carbon dioxide absorption were analyzed. After carbonation reaction, Concentration of dissolved inorganic cations and conversion of carbonation were analyzed by ion chromatography, thermogravimetric, x-ray diffraction, scanning electron microscope(SEM). Effluent was recycled MEA and water using RO system. These results Confirmed potential of CO2 reduction and Utilization of carbonation using industrial by-products.
        173.
        2015.03 KCI 등재 서비스 종료(열람 제한)
        CO2 emitted from building materials and construction materials industry reaches about 67 million tons, which occupy about 30% of CO2 emitted from the construction field. Controls on the use of consumed fossil fuels and reduction of emission gases are essential for the reduction of CO2 in the construction area as we reduce the second and third curing to emit CO2 in the construction materials industry. Accordingly, this study applied the low energy curing admixture (hereinafter “LA”) to the extruded panels to observe the physical properties, depending on the mixing amount of fiber, type of fiber and mixing ratio of fiber. The type of fiber did not appear to be a main factor to affect strength, while the LA mixing ratio and mixing amount of fiber appeared to be major factors to affect strength. Especially, the highest strength was developed when the LA mixing ratio was 40%, whereas the test object with the mixing ratio of 50% resulted in the decrease of strength. In addition, it appeared that the mixing ratio of fiber greatly affected flexural strength and strength increased as the mixing ratio increased.
        174.
        2015.02 KCI 등재 서비스 종료(열람 제한)
        Enlargement of street tree planting area is the proper and effective solution to reduce carbon dioxide. This solution bases on the ability of carbon storage and uptake by tree metabolism. However, the circumstance of road side has fatal disadvantages in tree metabolism such as growth and maturity because cutting and filling of roadsides cause unnatural soil composition. In this point, early rootage of street tree is the main factor of reducing carbon dioxide. This study aimed to find a appropriate transplantation planting method for sound and rapid rootage of street tree. For the study, Korean Mountain Ash(Sorbus alnifolia) were used for experimental groups. The groups were categorized by three groups such as trees produced on container with mulching treatment, trees produced in outdoor with mulching treatment, trees produced on container with weeding treatment. Each group consisted 10 trees with same size and transplanted in experimental site. Five months after transplanting, each group was estimated the biomass and carbon storage through a direct harvesting method. According to results of the study, the carbon storage of trees produced on container with mulching treatment is 42% more than trees produced in outdoor with mulching treatment. And the carbon storage of trees produced on container with mulching treatment is 19.5% more than trees produced on container with weeding treatment. These results may imply that transplantation of container produced tree with mulching treatment is the most rapid rootage among other groups. The weeding treatment is more effective than mulching treatment for rapid rootage of street trees.
        175.
        2015.01 KCI 등재 서비스 종료(열람 제한)
        Sustainable and eco-friendly polymers, natural polymers, bio-based polymers, and degradable polyesters, are of growing interest because of environmental concerns associated with waste plastics and emissions of carbon dioxide from preparation of petroleum-based polymers. Degradable polymers, poly(butylene adipate-co-terephthalate) (PBAT), poly(propylene carbonate) (PPC), and poly(L-lactic acid) (PLLA), are related to reduction of carbon dioxide in processing. To improve a weak mechanical property of a degradable polymer, a blending method is widely used. This study was forced on the component separation of degradable polymer blends for effective recycling. The melt-mixed blend films in a specific solvent were separated by two layers. Each layer was analysed by FT-IR, DSC, and contact angle measurements. The results showed that each component in the PPC/PLLA and PPC/PBAT blends was successfully separated by a solvent.
        176.
        2015.01 KCI 등재 서비스 종료(열람 제한)
        Recently, the energy supply uses mostly fossil fuels such as coal, petroleum, natural gas etc... however, they are limited and they present an issue for the environment. Biomass derived energy is considered promising for reducing the emissions of CO2, the significant contributor to global warming. Also it can be converted to various forms of energy through thermochemical conversion processes. In this study, a screw gasifier has been engineered for wood biomass gasification. Waste wood chip was used as biomass and the producer gas, tar; char were then achieved by gasification in the presence of CO2. The results showed that with the increase of the gasification temperature, the producer gas increased and the tar decreased. Also, due to thermal cracking, the light tar increased by the decomposition of the gravimetric tar. And a development of char pore structure was confirmed by SEM. The gasification of biomass in the presence of CO2 at 800oC produced an increase in the concentration of carbon monoxide according to the Boudoudard reaction and an increase in the char pore surface as well as its adsorption capacity. Thus the biomass gasification in the presence of CO2 was confirmed to be effective for the production of CO and the development of char.
        177.
        2014.12 KCI 등재 서비스 종료(열람 제한)
        Hydrochlorofluorocarbon (HCFC) is an ozone-depleting substance that is subject to environmental regulations based on the Montreal Protocol, and in Republic of Korea, which is regarded as a developing country, its use will be restricted in phase starting in 2013 until finally being prohibited in 2030. HCFC is regulated based on the Tokyo Protocol, HCFC is a regulated construction material for carbon dioxide reduction with GWP of 1,700 ~ 2,400 times that of CO2, with a GWP of 1. KS M 3808 than in the reference indicated in the C5 (15 : 15 : 20 : 50%) and C9 (20 : 10 : 20 : 50%) 0.33 mm 0.31 mm Cell size is shown in the analysis, etc. The compressive strength of the insulation, foaming agent mixing ratio according bending failure load, the thermal conductivity (initial and long-term), moisture permeability coefficient, combustible results, showed superior.
        178.
        2014.11 서비스 종료(열람 제한)
        The amount of carbon dioxide emission is continuously increasing and many researchers are concerned about climate change caused by its emission. Hence, some technologies which can reduce its emission have been developed and commercialized in many industries. These technologies are commonly called Carbon Capture and Storage (CCS) technology. In conventional CCS technology, carbon dioxide gas produced from industrial processes was usually captured by basic liquid absorbent such as monoethanolamine(MEA) and so on. After it is captured by those absorbents, they was flown to desorption step and was compressed at high pressure and transported to suitable places such as deep ocean or deep underground. However, there exist some problems when carbon dioxide is stored in such places. For instance, leak into the atmosphere can occur. Also, some nations including Korea may have difficulty finding suitable places for its storage since area of the nations is not that large and the ground is not stable. So, the method that can utilize captured carbon dioxide has been developed. When carbon dioxide is combined with metal cation such as calcium ion, it becomes calcium carbonate (CaCO3) which can be used for various purposes like construction materials, pharmaceutical manufacture, additives and so on. This is called Carbon Capture and Utilization (CCU) technology. In this research, seawater was used to supply calcium ions. There contained much amount of calcium component in seawater and amount of seawater is virtually limitless. MEA was used as absorbents and saturated by simulated flue gas. Pretreated seawater was then added to saturated absorbent. When carbon dioxide gas is dissolved to MEA, it exist in forms of ions and they can easily produce precipitated calcium carbonate (PCC) salts by reacting with calcium ions contained in seawater.
        179.
        2014.10 KCI 등재 서비스 종료(열람 제한)
        Carbon dioxide generated from construction materials and construction material industry among the fields ofconstruction is approximately 67million tons. It is about 30% of the carbon dioxide generated in the fields of construction.In order to reduce carbon dioxide in the fields of construction, it is necessary to control the use of fossil fuel consumedand decrease carbon emission by reducing the secondary and tertiary curing generating carbon dioxide in constructionmaterial industry. Therefore, this study produced an extrusion panel by using cement as the base materials and substitutingbinding materials up to 40% to analyze strength characteristics. According to the results of strength characteristics bythe replacement binder (Low energy curing Admixture) showed an apparent active strength improvement. In particular,specimens substituting binder as 45% indicated the greatest strength improvement. When binding materials was used withsubstitution, it showed strength characteristics similar or higher than specimens made from tertiary autoclave curing assecondary steam curing.
        180.
        2014.05 KCI 등재 서비스 종료(열람 제한)
        The effect of CO2 on the opening of stomata in the intact leaf of Commelina communis has been investigated. Full opening of stomatal apertures(around 18 μm) was achieved in the intact leaf by addition of CO2(900 μmol mol-1). At 90 minutes, the stomatal apertures of leaves treated with CO2 free air were reduced. In contrast, stomata opened most widely with the treatment of CO2 air at 90 minutes. The effects of light, CO2 air and CO2 free air on the change of membrane potential difference(PD) were measured. Fast hyperpolarization of guard cell membrane PD was recorded reaching up to -12 mV in response to light. If CO2 free air was given firstly, there was no response. When light was given after CO2 free air, the light effect was very clear. At the onset of CO2 air, the PD showed a dramatic hyperpolarization to about -25 mV. Changes in the pH of apoplast in intact leaves in response to CO2 air were observed. CO2 air caused a change of 0.4 pH unit. Therefore, it can be hypothesized that CO2 flowing could stimulate proton efflux which is a necessary precursor of stomatal opening.
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