• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2023년도 가을학술발표대회논문집
• /
• pp.205-206
• /
• 2023

In this study, the characteristics of cement were analyzed using carbon dioxide microbubble water as a mixed water for mineral carbonation of cement materials. Carbon dioxide reacts with the calcium compound of cement to produce calcium carbonate and affects the initial strength improvement. Therefore, in this study, temperature, air content, thermal analysis, and compressive strength tests were conducted to confirm the reaction between cement materials and carbon dioxide. As a result of the measurement, the reaction between cement and carbon dioxide was confirmed in a specimen using carbon dioxide microbubble water as a mixed water, which affected the initial strength improvement.

• 한국대기환경학회지
• /
• 제16권4호
• /
• pp.389-398
• /
• 2000

Photocatalytic removal of benzene from air was examined using titanium dioxide photocatalyst films prepared on soda lime glass(50$\times$50$\times$2 mm) by spin coating and chemical vapor deposition. For the measurement of photocatalytic reactivity titanium dioxide coated glass was placed into a batch reactor and concentration of benzene in the reactor was set to abuot 100 ppm, and then illuminated with UV. It was found that catalytic reactivity of titanium dioxide films increased with the increase of titanium dioxide film thickness and then level off beyond a certain film thickness. UV absorption by the films showed the similar trend. The formation of stoichiometric amount of carbon dioxide was confirmed by measurement of carbon dioxide concentration in the reactor. In general spin coated films revealed better photocatalytic reactivity than chemically deposited one within the experimental ranges covered in this study. Morphology and crystal structure of prepared films were investigated by XRD and SEM and they showed significant difference between spin coated films and CVD films. Highest quantum efficiency of prepared titanium dioxide photocatalyst was close to 50%.

• Korean Chemical Engineering Research
• /
• 제54권2호
• /
• pp.206-212
• /
• 2016

Experimental data are reported on the phase equilibrium of propoxylated neopentyl glycol diacrylate in supercritical carbon dioxide. Phase equilibria data were measured in static method at a temperature of (313.2, 333.2, 353.2, 373.2 and 393.2) K and at pressures up to 27.82 MPa. At a constant pressure, the solubility of propoxylated neopentyl glycol diacrylate for the (carbon dioxide + propoxylated neopentyl glycol diacrylate) system increases as temperature increases. The (carbon dioxide + propoxylated neopentyl glycol diacrylate) system exhibits type-I phase behavior. The experimental result for the (carbon dioxide + propoxylated neopentyl glycol diacrylate) system is correlated with Peng-Robinson equation of state using mixing rule. The critical property of propoxylated neopentyl glycol diacrylate is predicted with Joback and Lyderson method.

• Korean Chemical Engineering Research
• /
• 제57권6호
• /
• pp.826-831
• /
• 2019

Experimental data of phase equilibrium is reported for caprolactone acrylate in supercritical carbon dioxide. Bubble-point data was measured by synthetic method at temperatures ranging from (313.2 to 393.2) K and pressures up to 55.93 MPa. In this research, the solubility of carbon dioxide for the (carbon dioxide + caprolactone acrylate) system decreases as temperature increases at a constant pressure. The (carbon dioxide + caprolactone acrylate) system exhibits type-I phase behavior. The experimental result for the (carbon dioxide + caprolactone acrylate) system was correlated with Peng-Robinson equation of state using mixing rule. The critical property of caprolactone acrylate was predicted with the Joback and Lyderson method.

• 제어로봇시스템학회논문지
• /
• 제8권5호
• /
• pp.407-412
• /
• 2002

A measurement device for gas concentration and flow rate using hot wire is developed for the utilization in industrial applications. The device has two cells of measuring and reference, and a bridge circuit is installed to detect electric current through the hot wire in the cells. An amplification of the signal and conversion to digital output are conducted for the on-line measurement with a personal computer. The flow rate of air and carbon dioxide gas is separately measured for the performance examination of the device. Also, the concentration of air-carbon dioxide and carbon dioxide-argon mixtures is determined for the same evaluation. The outcome of the performance test indicates that the accuracy and stability of the device is satisfactory for the purpose of industrial applications.

• 한국환경과학회지
• /
• 제23권6호
• /
• pp.1131-1142
• /
• 2014

In this study, the variations of the carbon dioxide fluxes were investigated with soil temperatures in the grassplot and seasonal variations of carbon dioxide concentrations and fluxes were analysed. Soil temperatures, carbon dioxide concentrations and fluxes were measured on the grassplot in Pukyong National University. Field measurements were carried out 25 times from March in 2010 to March in 2011 with nine points on the grassplot. Seasonal variations of carbon dioxide concentrations and fluxes showed an inverse relation. In summer, carbon dioxide concentrations are lower and carbon dioxide fluxes are higher. In winter, carbon dioxide concentrations are higher and carbon dioxide fluxes are lower. On the grassplot, carbon dioxide emission rate increase when the soil temperature is more than $20^{\circ}C$ and the emission rate decrease when the soil temperatures are less than $10^{\circ}C$. When the accumulated rainfall for five days before measurement day is 20~100 mm, it is showed that the more rainfall, the more carbon dioxide emissions. Carbon dioxide emission rate from the grassplot to the upper atmosphere was increased or decreased by the factors such as soil temperature, growth and wither of grass and rainfall. The results of this study showed that the emission of carbon dioxide in the grassplot is dominantly controlled by seasonal factors (especially soil temperature and rainfall).

• 한국대기환경학회지
• /
• 제27권1호
• /
• pp.117-125
• /
• 2011

There are many studies reporting the average carbon dioxide levels in various indoor spaces. However, there have been a few studies showing how carbon dioxide concentration varied at many measurement points in one indoor space. In this study, the changes of indoor carbon dioxide concentration at classroom, library, and kindergarten were reported to find its carbon dioxide distribution change at various locations and altitudes. The maximum carbon dioxide concentration of the 3 sites were measured as 2,684, 2,295, and 1,526 ppm, respectively. These values exceeded the guideline concentration of 1,000 ppm for public places. The concentration of carbon dioxide was higher at upper area than lower area, and this is probably due to the rise of warm breathing air generated from students. In the upper area, the carbon dioxide concentration was higher at center area than four corners. However, in the lower area, the carbon dioxide concentration was higher at four corners than center area. Therefore, it could be concluded that the center of upper area is the best place for the installation of ventilation or carbon dioxide removal system.

• Corrosion Science and Technology
• /
• 제4권2호
• /
• pp.69-74
• /
• 2005

The carbonation of concrete is one of the major factors that cause durability problems in concrete structures. The rate of carbonation depends largely upon the diffusivity of carbon dioxide in concrete. The purpose of this study is to identify the diffusion coefficients of carbon dioxide for various concrete mixtures. To this end, several series of tests have been planned and conducted. The test results indicate that the diffusion coefficient increases with the increase of water-cement ratio. The diffusion coefficient decreases with the increase of relative humidity at the same water-cement ratio. The diffusion of carbon dioxide reached the steady state within about five hours after exposure. The content of aggregates also influences the diffusivity of carbon dioxide in concrete. It was found that the diffusion coefficient of cement paste is larger then that of concrete or mortar. The quantitative values of diffusivity of carbon dioxide in this study will allow more realistic assessment of carbonation depth in concrete structures.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2008년도 추계학술대회A
• /
• pp.1609-1612
• /
• 2008

RQ(Respiratory Quotient) value is obtained from the ratio of the consumed oxygen and the produced carbon dioxide during the patient's respiration. To investigate the efficacy of insulin and diagnosis the metabolic disorder in short time, the RQ value can be used as important parameter. The measurement of oxygen and carbon dioxide amounts is needed large chamber and complex sensors. But If the atmospheric oxygen and carbon dioxide concentrations do not change, the expiratory oxygen and carbon dioxide can be used to obtain RQ value. A convenient RQ measuring device has been developed by using two sensors for O2 and CO2. The estimation of RQ devices confirms that the RQ device can obtain accurate data by eliminating uncertain factor such as delay time and remaining gases.

• 센서학회지
• /
• 제29권2호
• /
• pp.128-132
• /
• 2020

Total organic carbon (TOC) analysis equipment, which was previously used to prevent eutrophication in advance, is heavy, bulky, and expensive; therefore, so it is difficult to be carried and has been used as an experimental unit. In this study, a through-carbon analysis chip that integrates pretreatment through photocatalytic oxidation and carbon dioxide measurement using a pH indicator was investigated. Both the total carbon - inorganic carbon method and the nonpurgeable organic carbon (NPOC) measurement method require an acidification part for injecting an acid solution for inorganic carbon measurement and removal, an oxidation part for total carbon or NPOC oxidation and a measurement part for Carbon dioxide (CO₂) measurement. Among them, the measurement of oxidation and CO₂ requires physical technology. The proposed TOC analysis chip decomposed into CO₂ as a result of the oxidizing of organic carbon using a photocatalyst, and the pH indicator that was changed by the generated CO₂ was optically measured. Although the area of the sample of the oxidation part and the pH indicator of the measurement part were distinguished in an enclosed space, CO₂ was quantified by producing an oxidation part and a measurement part that shared the same air in one chip. The proposed TOC analysis chip is less expensive and smaller, cost and size are disadvantages of existing organic carbon analysis equipment, because it does not require a separate carrier gas to transport the CO₂ gas in the oxidation part to the measurement part.