• Journal of Sensor Science and Technology
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• v.30 no.6
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• pp.446-450
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• 2021

Non-dispersive infrared (NDIR) gas sensors typically use an optical filter that transmits a discriminating 4.26 ㎛ wavelength band to measure carbon dioxide (CO2), as CO2 absorbs 4.26 ㎛ infrared. The filter performance depends on the transmittance and full width at half maximum (FWHM). This paper presents the fabrication, sensitivity, and selectivity characteristics of a distributed Bragg reflector (DBR)-based Fabry-Perot filter with a simple structure for CO2 detection. Each Ge and SiO2 films were prepared using the RF magnetron sputtering technique. The transmittance characteristics were measured using Fourier-transform infrared spectroscopy (FT-IR). The fabricated filter had a peak transmittance of 59.1% at 4.26 ㎛ and a FWHM of 158 nm. In addition, sensitivity and selectivity experiments were conducted by mounting the sapphire substrate and the fabricated filter on an NDIR CO2 sensor measurement system. When measuring the sensitivity, the concentration of CO2 was observed in the range of 0-10000 ppm, and the selectivity was measured for environmental gases of 1000 ppm. The fabricated filter showed lower sensitivity to CO2 but showed higher selectivity with other gases.

• Journal of Microbiology and Biotechnology
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• v.17 no.3
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• pp.414-419
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• 2007

Botryococcus braunii is a green colonial fresh water microalga and it is recognized as one of the renewable resources for production of liquid hydrocarbons. CFTRI-Bb-l and CFTRI-Bb-2 have been reported for the first time and their performance with regard to growth and biochemical profile is presented here. The present study focused on effect of carbon dioxide $(CO_2)$ on biomass, hydrocarbon, carbohydrate production, fatty acid profile, and carotenoid content in various species of B. braunii (LB-572, SAG 30.81, MCRC-Bb, N-836, CFTRI-Bb-l, and CFTRI-Bb-2) at 0.5, 1.0, and 2.0% (v/v) levels using a two-tier flask. $CO_2$ at 2.0% (v/v) level enhanced growth of the organism, and a two-fold increase in biomass and carotenoid contents was observed in all the B. braunii strains studied compared with control culture (without $CO_2$ supplementation). At 1 % and 2% (v/v) $CO_2$ concentrations, palmitic acid and oleic acid levels increased by 2.5 to 3 folds in one of the strains of B. braunii (LB-572). Hydrocarbon content was found to be above 20% at 2% $CO_2$ level in the B. braunii LB-572, CFTRI-Bb-2, CFTRI-Bb-l, and N-836 strains, whereas it was less than 20% in the SAG 30.81 and MCRC-Bb strains compared with control culture. This culture methodology will provide information on $CO_2$ requirement for growth of algae and metabolite production. B. braunii spp. can be grown at the tested levels of $CO_2$ concentration without much influence on culture pH.

• Nuclear Engineering and Technology
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• v.55 no.9
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• pp.3194-3201
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• 2023

In water-cooled power reactor, hydrogen is generated in case of steam zirconium reaction during severe accident condition and later on in addition to hydrogen; CO is also generated during molten corium concrete interaction after reactor pressure vessel failure. Passive Autocatalytic Recombiners (PARs) are provided in the containment for hydrogen management. The performance of the PARs in presence of hydrogen and carbon monoxide along with air has been evaluated. Depending on the conditions, CO may either react with oxygen to form carbon dioxide (CO2) or act as catalyst poison, reducing the catalyst activity and hence the hydrogen conversion efficiency. CFD analysis has been carried out to determine the effect of CO on catalyst plate temperature for 2 & 4% v/v H₂ and 1-4% v/v CO with air at the recombiner inlet for a reported experiment. The results of CFD simulations have been compared with the reported experimental data for the model validation. The reaction at the recombiner plate is modelled based on diffusion theory. The developed CFD model has been used to predict the maximum catalyst temperature and outlet species concentration for different inlet velocity and temperatures of the mixture gas. The obtained results were used to fit a correlation for obtaining removal rate of carbon monoxide inside PAR as a function of inlet velocity and concentrations.

• KEPCO Journal on Electric Power and Energy
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• v.2 no.4
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• pp.517-523
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• 2016

South Korea is the 8th biggest greenhouse gas emitter in the world due to its phenomenal economic growth based on manufacturing, and it is ranked first among OECD members for the rate of increase in emissions. Thus, the Korea government has voluntarily presented a reduction target and demonstrated global leadership. For the reduction of nation's GHG emission, importance of CCU(Carbon Capture and Utilization) along with CCS(Carbon Capture and Storage) technology development is increased. CCU technology is $CO_2$ utilization technology for the usage of $CO_2$ from flue gas and it can create a new economic value while reducing $CO_2$ emission. Therefore, with continued technology development, the number of application of CCU technology is increasing globally.

• Journal of Environmental Science International
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• v.22 no.9
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• pp.1235-1239
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• 2013

The effects of probiotic additions to feed and manure on temperature, humidity and carbon dioxide ($CO_2$) emissions in Hanwoo manure during summer (4 weeks) were evaluated. Fifteen Hanwoo (24-mo-old, $580{\pm}20kg$) were housed in individual pens ($5{\times}8m$) and randomly assigned to 1 of 3 treatments (n = 5 cattle per treatment). Hanwoo were fed experimental rations as follows: control (10 kg roughage + 2 kg concentrate); T1 (10 kg roughage + 2 kg concentrate, 2% probiotics on as-fed basis); and T2 (10 kg roughage + 2 kg concentrate, 2% probiotics on as-fed basis + 7 kg probiotics as top-dressing on the surface of Hanwoo manure). In comparison to the control, the addition of probiotics to feed or feed and manure had an effect (P < 0.05) on temperature and humidity over the 4 weeks, except for humidity at 0 weeks. The only significant difference (P < 0.05) observed in $CO_2$ emission was among all treatments at 3 and 4 weeks (but not at 0 through 2 weeks). These results indicated that use of probiotics as feed and manure additives did not have a significant effect on environmental parameters.

• Tunnel and Underground Space
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• v.20 no.5
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• pp.309-317
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• 2010

CCS (Carbon dioxide Capture and Storage) is a means of mitigating the contribution of $CO_2$ to the Greenhouse gas, from large point sources such as power plants and steel companies. CCS is a process whereby $CO_2$ is captured from gases produced by fossil fuel combustion, compressed, transported and injected into deep geologic formations for permanent storage. CCS applied to a conventional power plant can reduce $CO_2$ emissions to the atmosphere by approximately 80~90% compared to a plant without CCS. The IPCC estimates that the economic potential of CCS will be between 10% and 55% of the total carbon mitigation effort by year 2100. In this paper, overseas sites where CCS technology is being applied and technical development trends for CCS are briefly reviewed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.10
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• pp.136-152
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• 2017

The thermodynamic models, PC-SAFT (Perturbed-Chain Statistical Associated Fluid Theory) state equation and the Two-model approach liquid activity coefficient model NRTL (Non Random Two Liquid) + Henry + Peng-Robinson, for modeling the Rectisol process using methanol aqueous solution as the $CO_2$ removal solvent were compared. In addition, to determine the new binary interaction parameters of the PC-SAFT state equations and the Henry's constant of the two-model approach, absorption equilibrium experiments between carbon dioxide and methanol at 273.25K and 262.35K were carried out and regression analysis was performed. The accuracy of the newly determined parameters was verified through the regression results of the experimental data. These model equations and validated parameters were used to model the carbon dioxide removal process. In the case of using the two-model approach, the methanol solvent flow rate required to remove 99.00% of $CO_2$ was estimated to be approximately 43.72% higher, the cooling water consumption in the distillation tower was 39.22% higher, and the steam consumption was 43.09% higher than that using PC-SAFT EOS. In conclusion, the Rectisol process operating under high pressure was designed to be larger than that using the PC-SAFT state equation when modeled using the liquid activity coefficient model equation with Henry's relation. For this reason, if the quantity of low-solubility gas components dissolved in a liquid at a constant temperature is proportional to the partial pressure of the gas phase, the carbon dioxide with high solubility in methanol does not predict the absorption characteristics between methanol and carbon dioxide.

• Membrane Journal
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• v.33 no.5
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• pp.240-247
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• 2023

Even among gas separation methods, CO₂ capture and separation via membranes is an ever-growing field, with many different membrane compositions continually being developed. Ionic liquid (IL) based composite membranes show excellent performance values in separating CO₂. Similarly, various copolymer/IL composite membranes also display improved performance. The addition of fillers such as graphene oxide to these copolymer/IL composite membranes shows a further enhanced version of these fillers, most likely due to the strong interactions that occur between ILs and organic fillers, which consequently improves factors such as the affinity, selectivity, and adsorption of CO₂. Copolymer/IL composite membranes utilizing a metal-organic framework (MOF) showed improved CO₂ permeability. This review discusses the study of various combinations of ionic liquid and copolymer composite membranes for carbon dioxide separation.

• Journal of Mushroom
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• v.10 no.2
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• pp.57-62
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• 2012

The plastic culture bottle cap types and accumulated concentration of carbon dioxide, media humidity in the process of medium culture, chitin content and yield were observed in Pleurotus ostreatus 850ml bottle in Iksan, Jeollabuk-do, Korea, during 2011. The concentration of carbon dioxide in the process of medium culture was the highest after 8~9 days cultivation irrespective of cap sizes and types. The accumulated concentration of carbon dioxide in size cap of 29~41mm was 6.5~4.0% in the upper-under perforation hole of cap and 9.0~6.5% in the under perforation hole of cap. The upper-under 23~33mm perforation hole and under 29mm perforation hole of caps in the 850ml bottle were best condition for cultivation of mushroom and increased fruit body, 15.8~21.2% and 20%, respectively. However, the upper-under & under 41mm perforation hole of fruit body were decreased 60.7% and 23.6%, respectively. Also it was weak, lose vitality and the lower of biologically activity substance because the upper medium humidity was too dry.

• Elastomers and Composites
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• v.46 no.2
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• pp.118-124
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• 2011

Recently, the need of new materials which have excellent physical properties and functional characteristics has been increased in all industries. In particular, body weight reduction via new materials in aerospace industry was significantly emphasized by the requirement of environmental protection through the fuel savings and reduction of greenhouse gas, i.e., carbon dioxide($CO_2$). Also, for various applications, the development of high performance custom materials with excellent physical properties was the current primary goal of materials science and technology. In this respect, carbon fiber-reinforced composites were the most candidates among the various materials. Indeed, carbon fiber-reinforced composites have been lately used as essential materials for the weight reduction of aircraft and the demand has increased remarkably. Therefore, in this paper, we focused on the need of carbon fiber composites in the fields of aircraft and technique status.