• Advances in environmental research
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• v.11 no.1
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• pp.17-30
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• 2022

Road transport allows all forms of land conditions to be met at less cost. Because of this function, despite numerous disadvantages, it becomes the most frequently used method of transport, especially in underdeveloped or developing countries. One of the most significant factors used in evaluating the atmosphere's air quality is the amount of CO₂, increasing people's density in indoor spaces. The amount of CO₂ indoors is, therefore, vital to determine. In this study, CO₂ and temperature measurements made on nine different bus journey was made in Turkey. The minimum and maximum values were recorded as 555 ppm and 3000 ppm CO₂, respectively, in the measurements. On all journeys, the average concentration is 1088.72 ppm. The minimum and maximum values were measured as 17.4℃ and 32.7℃ in the temperature measurements, and the average of all trips was calculated to be 25.76℃. In this study conducted before the Covid-19 pandemic, it was determined that the amount of CO₂ increased with the density and insufficient ventilation in the buses. The risk of infection increases in places with high human density and low clean air. For situations such as pandemics, CO₂ measurement is a rapid indicator of determining human density.

• The Journal of the Korea Contents Association
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• v.14 no.12
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• pp.999-1009
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• 2014

In this paper, $CO_2$ emission and storage amount are evaluated for real RC (Reinforced Concrete) underground structure considering $CO_2$ amount including material manufacturing, moving, and construction, repairing timing stage regarding extended service life. Four mix proportions with mineral admixtures are prepared and $CO_2$ diffusion coefficient are obtained based on a micro modeling. Referred to carbonation durability limit state, $CO_2$ emission and storage amount are evaluated, which shows higher initial $CO_2$ emission is caused due to larger unit content of cement and the storage increases with more rapid carbonation velocity. Furthermore various $CO_2$ concentration is adopted for simulation of $CO_2$ evaluation including measured $CO_2$ concentration (600ppm). With higher concentration of $CO_2$ outside, carbonation velocity increases. In order to reduce $CO_2$ emission through entire service life, reducing initial $CO_2$ emission through mineral admixture like fly ash is more effective than increasing $CO_2$ storage through OPC since $CO_2$ is significantly emitted under manufacturing OPC and $CO_2$ storage in cover concrete of RC structure is not effective considering initial concrete amount in construction.

• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.1484-1490
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• 2009

Since the cooling performance of a $CO_2$ cooling cycle is varied significantly with a variation of refrigerant charge amount and outdoor temperature, the reliability of $CO_2$ system is down. In this study, the performance characteristics of three kinds of $CO_2$ systems were measured and analyzed by varying refrigerant charge amount and outdoor temperature so as to study the characteristics of variation with cycle option. The applied system options are the single-stage compression(1C-1E) system, two-stage compression with 1-EEV(2C-1E) system, and two-stage compression with 2-EEV(2C-2E) system. The performances of two-stage compression with 2-EEV system were less sensitive than those of other systems and the system operated safely and steadily for wide charge amount. The performance of the two-stage compression with 1-EEV(2C-1E) system was the most sensitive to the charge amount, and that of the single-stage compression(1C-1E) system varied a lot with outdoor temperature.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.11a
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• pp.226-226
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• 2003

The Commercial LiCoO$_2$ particles, which were 7.7${\mu}{\textrm}{m}$ in average diameter, were coated with $Al_2$O$_3$ by a gas suspension spray coating method. The coating amount of $Al_2$O$_3$ on the surface of LiCoO$_2$ was varied from 0.1 to 2 wt.% and compared their electrochemical characteristics with those of bare LiCoO$_2$. $Al_2$O$_3$ coating on the surface of LiCoO$_2$ increased surface area and electrical conductivity, and showed the better cycle and thermal stability even at the higher voltage. The observed optimum A1$_2$O$_3$ coating amount that exhibited the highest capacity retention was 0.2 wt.%.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.317-318
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• 2023

This study is part of the carbonation degree DB accumulation through quantitative analysis of carbonation depth, Ca(OH)₂ and CO₂ according to the type of finish and years of use of old concrete structures in order to predict the amount of CO₂ that can be absorbed through carbonation of concrete. To this end, the depth of carbonation of the concrete core specimen is measured using an indicator, and the dry amount of water combined with CO₂ in the sample is measured using a differential thermal gravimetric analyzer for samples in the carbonation area and non-carbonated area classified by the indicator, and the absorption compared to the weight of the sample. The amount of absorbed CO₂ was calculated. In addition, the degree of carbonation was calculated through quantitative comparison of Ca(OH)₂ in the carbonation section and non-carbonation section. In the future, we will continue to add the survey and analysis data of dismantled structures and use them as basic data for estimating the amount of carbon dioxide that can be absorbed according to the exposure conditions and years of use by concrete mix.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.8 s.179
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• pp.1885-1898
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• 2000

Welding quality is closely related to the arc state. So, it is very important to estimate the arc state in real time. In the short circuit transfer region of CO2 are welding, the spatter , as it is well known, is mainly generated on an instance of short circuit or on an instance that the are is ignited after short circuit, or on the cases of an instantaneous short circuit. If the short circuit period or the arc time is irregular, the spatter is generated more than it is regular. Thus there is a close relationship of the amount of the spatter generation with the arc stability. In this paper, to develop the index for estimating the arc stability in short circuit transfer range Of CO2 arc welding, the welding current and are voltage waveforms were measured and the spatter generated was captured and measured. The correlation analysis of the measured amount of the spatter with the factors (the components and the standard deviations of the components) was performed, and the factors that have a considerable influence on the spatter generation among all factors were selected. And some cases of models consisted of the factors were presented, and a mathematical index model which can make an estimation the amount of the spatter from these models with multiple regression analysis. Also, it was compared how much the amount of the spatter generated under the selected welding conditions do these index models fit, and the index model to estimate the arc stability which represent the spatter generation most appropriately was developed

• Bulletin of the Korean Chemical Society
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• v.24 no.11
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• pp.1623-1626
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• 2003

The dependency of the rate of $CO_2$ reforming of methane on the catalyst loading and the reactor size was examined at a fixed temperature of $750\;^{\circ}C$ and a fixed GHSV of 18000 mL(STP)/$g_{cat}.h$. The conversion of methane in $CO_2$reforming decreased with increase in the reactor size. The catalyst was severely deactivated with increase in the catalyst amount. The amount of carbonaceous species combustible below $550\;^{\circ}C$, determined by TPO experiments with the used catalyst samples increased with increase in the catalyst amount, which was again confirmed by XRD and TEM experiments. The increase of the carbonaceous species combustible below $550\;^{\circ}C$ may be due to the suppression of the reverse Boudouard reaction, since the $CO_2$ reforming of methane, a highly endothermic reaction, resulted in lowering the reaction temperature.

• The Journal of Korean Academy of Prosthodontics
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• v.29 no.2
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• pp.295-317
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• 1991

The discrepancy between centric relation and centric occlusion have a great role on the successful prosthodontic and occlusal treatment. This study was performed to investigate the effect of the discrepancy between centric relation and centric occlusion on condylar guidance inclination and Bennett shift (immediate and progressive side shift). Sixteen adults who have physiologically normal occlusion and are free of TMJ dysfunction were selected. The amount of the sagittal CR-CO discrepancy in lower anterior incisor was obtained by Saphon Visi-Trainer. The amount of the CR-CO discrepancy in condylar level was measured on the individualized corrected tomography. Pantronic survey was performed by using a arbitrary hinge axis according to manufacturer's direction. All subjects were divided into two groups, group I (small) and group II (large), according to the amount of CR-CO discrepancy. At first the amount of the CR-CO discrepancy in condylar level between two groups was compared and then the condylar guidance inclination and Bennett shift between two groups were compared and analyzed. The results were as follows; 1. The average CR-CO discrepancy in lower anterior incisors was 0.7mm superoinferiorly, 0.49mm anteroposteriorly, and 0.88 mm in total. The average CR-CO discrepancy in condylar level was 0.43mm. 2. The CR-CO discrepancy measured on teeth level and condylar level were highly correlated (p<0.01). 3. The correlation of the condylar position in the glenoid fossa between two groups was not statistically significant. 4. The large CR-CO discrepancy group showed greater amount of Bennett shift and condylar guidance inclination, but there is no statistical significancy. 5. It seems that the CR-CO discrepancy have greater effect on progressive side shift than other elements of mandibular movements.

• Journal of Korean Society for Atmospheric Environment
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• v.31 no.4
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• pp.356-367
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• 2015

A consumption based study on the carbon dioxide ($CO_2$) emission change due to the changes in the bovine meat consumption behavior in Korea was carried out. It was found that if the consumption of bovine meat be reduced by half, the reduction amount of $CO_2$ emissions be over 0.8 $MtCO_2e$ in all senarios in 2023. This amount is equivalent to over 50% of the greenhouse gases (GHGs) emission reduction target in agriculture and forestry, and fishery, a significant reduction. It was also found that the $CO_2$ emission reduction amount in consumption-based approach was the largest when the consumption of the imported bovine meat be reduced, though the difference was not that large.

• Proceedings of the KAIS Fall Conference
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• 2007.11a
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• pp.375-377
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• 2007

The purpose of this study was to investigate total $CO_2$ amount of steel and reinforced concrete construction, and compare and analyze $CO_2$ amount on construction-material. And then it was studied about new element that environment compatibility of architecture structure design based on paradigm of environment age. Architecture action should have proceeded course that reduce burden of the earth environment in relation between architecture and environment and increase contact of human and nature. As environment compatibility development is emphasized with architecture development, architecture structure design give improvement of one important element that environment compatibility except stability, function, economy and necessary propriety of environment compatability of construction design.