• Transactions of the Korean Society of Mechanical Engineers B
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• v.41 no.10
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• pp.639-647
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• 2017

This basic study is focused on the physically removal method of carbon dioxide from the decomposition of ammonium carbarmate to prevent the recombination of ammonium salts. A basic visual experimental set-up was designed and constructed to observe the recombination phenomena from the proper composition of ammonia gas, carbon dioxide gas, and compressed air dilution gas. To quantify the recombination phenomena, a simple device was designed to measure the weight change under severe cases for three different tube sizes. The temperature and pressure in the visual tube and the volumetric flow rates of the nitrogen dilution gas were studied and the conditions to avoid recombination were analyzed according to mean free path theory. Diffusivity values based on the Chapman-Enskog theory were calculated from the experimental data. These value may serve as an index for the prevention of recombination.

• Korean Journal of Pharmacognosy
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• v.30 no.1
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• pp.59-64
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• 1999

Supercritical fluid extraction (SFE) technique was applied to extract cytotoxic substances from five medicinal plants including Angelica gigas, Angelica acutiloba, Aralia cordata, Spirodela polyrhiza, Bupleurum falcatum, and Acanthopanax sessiliflorus. The cytotoxicities against P388, A549, and HL-60 cell lines were determined for the supercritical carbon dioxide extracts of five plant materials employed and were compared with those of the conventional organic solvent extracts such as n-hexane, $CHCl_{3}$, and MeOH to evaluate the SFE as an alternative method to conventional organic solvent extraction. In most cases, the SFE extracts of plant materials showed enhanced cytotoxicities when compared with those of other organic solvent extracts. In addition, the optimum temperature and pressure of SFE for extraction of the cytotoxic substances were largely affected by both the plant species and the cell lines tested. These results suggested that SFE could be an alternative to the conventional organic solvent method for the selective extraction of cytotoxic compounds from plants.

• Food Science of Animal Resources
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• v.37 no.1
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• pp.29-37
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• 2017

Defatted bovine liver (DBL) is a potential source of protein and minerals. Supercritical carbon dioxide ($SC-CO_2$) and a traditional organic solvent method were used to remove lipid from bovine liver, and the quality characteristics of a control bovine liver (CBL), bovine liver defatted by $SC-CO_2$ ($DBLSC-CO_2$) at different pressures, and bovine liver defatted by organic solvent (DBL-OS) were compared. The $DBLSC-CO_2$ samples had significantly higher (p<0.05) protein, amino acid, carbohydrate, and fiber contents than CBL and DBL-OS. There was a higher yield of lipid from CBL when using $SC-CO_2$ than the organic solvent method. SDS-PAGE analysis demonstrated that the CBL and $DBLSC-CO_2$ had protein bands of a similar intensity and area, whereas DBL-OS appeared extremely poor bands or no bands due to the degradation of proteins, particularly in the 50 to 75 kDa and 20 to 25 kDa molecular weight ranges. In addition, $DBLSC-CO_2$ was shown to have superior functional properties in terms of total soluble content, water and oil absorption, and foaming and emulsification properties. Therefore, $SC-CO_2$ treatment offers a nutritionally and environmentally friendly approach for the removal of lipid from high protein food sources. In addition, $SC-CO_2$ may be a better substitute of traditional organic solvent extraction for producing more stable and high quality foods with high-protein, fat-free, and low calorie contents.

• Journal of the Society of Disaster Information
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• v.18 no.3
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• pp.589-599
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• 2022

Purpose: The purpose of this study is to quantitatively identify the environmental contribution generated by urban rail users in the metropolitan area. Method: As for the analysis method, the mode choice and assignment of the traffic demand analysis were repeatedly performed on the assumption that each line was not opened for the metropolitan urban railway lines 1 to 9. After that, the environmental contribution according to changes in demand for the road was analyzed. Result: The total amount of carbon dioxide emissions and benefits were found to be the largest for subway line 1. However, when considering the number of stations and length, it was analyzed that the environmental contribution was the greatest in Metro Line 4. Conclusion: Measures to promote the use of public transportation are representative of environmental improvement policies, but there is a limit in that it is difficult for actual users/non-users to feel it. Therefore, it is judged that it is necessary to quantitatively present the effect in order to improve and spread awareness of the environment.

• 한국신재생에너지학회:학술대회논문집
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• 2006.11a
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• pp.66-69
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• 2006

The idea of $CO_2$ sequestration in the ocean is proposed to be an effective mitigation strategy to counteract potential global warming due to the greenhouse effect Therefore, in the present study, calculations of the dissolution behavior of $CO_2$ hydrate when liquid carbon dioxide is released at 1,000m and 1,500m in depth are performed. The results show the liquid $CO_2$ injected in the ocean becomes $CO_2$ bubble at between 350m and 500m in depth, and the injection from a moving ship is a more effective method of dissolution than through a fixed pipeline. It so also noted that the ultimate plume generated from $CO_2$ bubbles repeats expansion and shrinking due to the peel ins from a fixed pipeline.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.217-218
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• 2010

This study presented the analytical evaluation model effective in the concrete structure repaired with a patching material. The model considered the effect of the repair material on carbon dioxide penetration into the repaired concrete as evaluating the remaining service life of the CO2-deteriorated concrete structure after repair. The diffusion profiles of carbon dioxide as well as the carbonated concrete were effectively able to be modelled with analytical method based on Fick's 1st diffusion law.

• IEMEK Journal of Embedded Systems and Applications
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• v.11 no.5
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• pp.299-304
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• 2016

As public interest in air quality and environment problem is increasing, many researches are being carried out the gas measurement system. Especially, Non-dispersive infrared (NDIR) measurements using Beer-Lambert gas sensing principle with very high selectivity and long life time are noted for reliable method. It is possible to detect various gases such as carbon dioxide (CO2), carbon monoxide (CO), and nitrogen dioxide (NO2), but many researches are mostly concentrated on CO2 sensor. The multi-gas measuring instrument is high price and unwieldy, therefore it is not suitable for wide area required numerous instrument. So we study the NDIR multi-gas measurement system for air quality based on wireless sensor network, and experiment the realized measurement system.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.5
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• pp.860-865
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• 1997

Investigations were performed on the effects of extraction temperature, pressure, time on solubility and selectivity of egg yolk lipid and cholesterol, and color and fatty acid composition of the residue in supercritical carbon dioxide(SC-Co$_2$) extraction. Lipid and cholesterol solubility increased as the increase of Co$_2$ density and was found to strongly depend on the extraction pressure rather than the extraction temperature. The relative concentration of cholesterol in the extract increased with an increase in temperature and decreased with an increase in pressure and extraction time. extraction of dried eg yolk for 3hr at 4$0^{\circ}C$/276 bar removed 46.1% of cholesterol from the residual egg yolk with a yield of 63.2%. SC-Co$_2$ extraction produced a lighter color egg yolk with less redness and yellowness. As the extraction time increased, the resultant residual egg yolk became more saturated with fatty acids. SC-$CO_2$ extraction offers a safe, natural method for removing cholesterol from dried egg yolk.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.323-324
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• 2005

To found out the degradation characteristic of transformer insulation, insulation materials and electrodes are deposited into transformer oil. They used to heated and make flashover. Due to the thermal and electrical stress added to insulation materials, the density of carbon dioxide and hydrogen included in transformer oil was increased. The gas density can measured by using the gas density detection equipment of gas sensor and air circulation method.

• Journal of the Korea Furniture Society
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• v.22 no.2
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• pp.118-125
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• 2011

These days global warming is the most important problem and the most important factor is high emission of carbon dioxide. The 23% of carbon dioxide emission for building construction must be reduced. Thermal conductivity is the most basic factor that can decrease the energy consumption especially insulation. Therefore, an accurate and continuous thermal conductivity measurement can be a way to save energy. In this paper, there are methods about how to investigate thermal conductivity measurements and comparing two methods which are the Heat Flow Meter 436 and TCi.