• Environmental Engineering Research
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• v.22 no.1
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• pp.40-54
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• 2017

According to FAO, "agricultural sectors are particularly exposed to the effects of climate change and increases climate variability". As a result, the study makes an attempt to answer the question: Is there a causal effect between agricultural production and carbon dioxide emissions in Ghana? By employing a time series data spanning from 1960 to 2015 using the Autoregressive Distributed Lag method. There was evidence of a long-run equilibrium relationship running from copra production, corn production, green coffee production, milled rice production, millet production, palm kernel production and sorghum production to carbon dioxide emissions. The short-run equilibrium relationship shows that, a 1% increase in copra and green coffee production will increase carbon dioxide emissions by 0.22% and 0.03%, a 1% increase in millet and sorghum production will decrease carbon dioxide emissions by 0.13% and 0.11% in the short-run while a 31% of future fluctuations in carbon dioxide emissions are due to shocks in corn production. There was bidirectional causality between milled rice production and carbon dioxide emissions, millet production and carbon dioxide emissions and, sorghum production and carbon dioxide emissions; and a unidirectional causality running from corn production to carbon dioxide emissions and carbon dioxide emissions to palm kernel production.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.215-219
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• 2001

Impurities removal from waste carbon black was carried out to produce high-grade carbon black. A lot of hydrophilic carbon black is produced as a byproduct of the hydrogen production process by flame decomposition of water. Due to its impurity content such as sulphur, iron, ash and etc., it can only be used as low-grade carbon or burnt out. High-grade hydrophilic carbon black is 3-5 times more expensive than oil-based carbon black because of its process difficulties and requires pollutant treatment. Hydrophilic carbon is normally used far conductive materials for batteries, pigment for plastics, electric wire covering, additives for rubber, etc.. In these applications, hydrophilic carbon must maintain its high purity. In this study magnetic separation, froth flotation and ultrasonic treatment were employed to remove impurities from the low-grade hydrophilic carbon black. As results, the ash, iron and sulphur content of product decreased to less than 0.01wt.%, 0.0lwt.% and 0.3wt.% respectively, and the surface area of product was about 930 $m^2$/g.

• Carbon letters
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• v.9 no.4
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• pp.316-323
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• 2008

The factors that influence ablation resistance in fiber composites are properties of the reinforced fiber and matrix, plugging quantity of fiber, geometrical arrangement, crack, pore size, and their distributions. To examine ablation resistance according to distribution of crack and pore size that exist in carbon/carbon composites, this study produced various sizes of unit cells of preforms. They were densified using high pressure impregnation and carbonization process. Reinforced fiber is PAN based carbon fiber and composites were heat-treated up to $2800^{\circ}C$. The finally acquired density of carbon/carbon composites reached more than $1.932\;g/cm^3$. The ablation test was performed by a solid propellant rocket engine. The erosion rate of samples is below 0.0286 mm/s. In conclusion, in terms of ablation properties, the higher degree of graphitization is, the more fibers that are arranged vertically to the direction of combustion flame are, and the less interface between reinforced fiber bundle and matrix is, the better ablation resistance is shown.

• Composites Research
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• v.13 no.6
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• pp.55-62
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• 2000

The strength test was done for the Carbon/Carbon rotor disk which is the critical part of a carbon/carbon brake system in an operating time. The loading fixture was designed for the static strength test of a single carbon/carbon brake disk using finite element analysis. To simulate the real dynamic system in a static condition, the friction surface of the rotor disk was fixed and static load was applied to the rotor slot in the circumferential direction. The described failure mechanism of the brake disk can be described as matrix cracking occurred first at the contact surface of the rotor slot, subsequent delamination from the cracked contact surface, and the final fracture at the notch of the rotor.

• Textile Coloration and Finishing
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• v.22 no.1
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• pp.43-50
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• 2010

The thermal treatment for carbon nanotube was applied to remove the water, metal catalyst and other impurities in carbon nanotube. The surface of carbon nanotube was changed into open structure with acid treatment by mixed solution of $HNO_3$ and $H_2SO_4$. The dispersion property of the functionalized and modified carbon nanotube was assessed with naked eyes by dispersing it in DMF. Carbon nanotube mixd polyurethane film was made to estimate the dispersion property by reflectance of the film with UV-Vis spectrometer. Also the internal structure of carbon nanotube was observed with SEM and TEM and thermal pyrolysis property of the carbon nanotube was measured by TGA and DSC. The surface modification of carbon nanotube by thermal and acid treatments improved the dispersion property of carbon nanotube/polyurethane mixed materials.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.15 no.9
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• pp.718-726
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• 2003

Carbon dioxide ocean disposal is one of the promising options to reduce carbon dioxide concentration in the atmosphere because the ocean has vast capacity for carbon dioxide sequestration. However, the dissolution rate of liquid carbon dioxide in seawater must be known in advance in order to estimate the amount of carbon dioxide sequestration in the ocean. Therefore, in the present study, calculations of the solubility, the surface concentration and the dissolution behavior of carbon dioxide when liquid carbon dioxide is released at 1,000m and 1,500m in depth are peformed. The results show that the droplet is completely dissolved below 500 m in depth if the carbon dioxide droplet is released both at 1,000m in depth with the initial droplet diameter of 0.011m or less and at 1,500m in depth with the diameter of 0.016 or less. Also, the surface concentration of carbon dioxide droplet with the hydrate film is about 50% of carbon dioxide solubility at 1,500 m in depth and about 60% of carbon dioxide solubility at 1,000 m in depth.

• Journal of Animal Science and Technology
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• v.62 no.1
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• pp.74-83
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• 2020

Organic waste used as a feedstock in the anaerobic digestion (AD), it includes carbon and nitrogen. Carbon and nitrogen have an effect on the various digestive characteristics during AD, however, the study is rare about those of the interaction. This study investigates the influence of carbon type and carbon to nitrogens (C/N ratios) on the AD characteristics of organic waste. Experimental treatments involved a combination of three carbon types with three C/N ratios. The AD tests were carried out using a 125-mL serum bottle at a constant temperature of 37℃ and moisture 95% for 18 days. Degradation pattern shows the difference among three-carbon treatments, the starch group was faster than other groups. Maximum methane production date was similar between starch (9.96 ± 0.05 day) and xylan group (10.0 ± 0.52 day), those of the cellulose group (14.6 ± 1.80 day) was slower than other groups (p < 0.05). The lag phase was only affected by the carbon type (p < 0.05). Ammonia nitrogen was mainly affected by nitrogen concentration regardless of carbon type (p < 0.05). This study showed that xylan is useful as feedstock in order to decrease the lag phase, and it showed that ammonia was independently affected by the nitrogen concentration.

• Journal of Korean Elementary Science Education
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• v.23 no.2
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• pp.152-158
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• 2004

The purpose of this study was to find the difficulties and problems in the carbon dioxide production experiment and to suggest the device for the improvement. Many students have misconception for the smell of carbon dioxide. I found that the smell of carbon dioxide of producting through the experiment didn't concern with the quantity of calcium carbonate. I certificated that the smell of carbon dioxide was related with the concentration of hydrochloric acid. I built two trap applicaing suction in the gas production device to exclude fully the smell of carbon dioxide. So the smell of carbon dioxide was not present by passing the two trap. To find the ideal experimental conditions I perform the experiment step by step. As the result enough carbon dioxide to use for the property experiment was collected under the condition that is 60 mL of 3 molarity hydrochloric acid and 30 g calcium carbonate. I certificated to mesuring flowing quantity of carbon dioxide using the flow meter of carbon dioxide. In the improvement experiment of the property of carbon dioxide, I proposed the experiment device regarding as spreading of the gas and children's interest. To improve the problem of gas production experiment, I proposed the gas certification device using a thread.

• Journal of Ecology and Environment
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• v.29 no.5
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• pp.433-438
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• 2006

To elucidate the mechanisms by which algal food quality affect Daphnia growths, we measured carbon incorporation rates and respiration rates of Daphnia magna with Cryptomonad Rhodomonas minuta, green algae Scenedesmus acutus and cyanobacteria Synechococcus sp. with varying physiological states as food. Carbon assimilation rates were high with R. minuta and S. acutus and low with Synechococcus sp. showing a similar pattern to the growth rate pattern. There was no clear difference among respiration rates of three algal species. Carbon assimilation rates and respiration rates of D. magna appeared to be independent on Molar C:P ratios in algal foods. Carbon growth efficiencies (incorporated carbon per assimilated carbon amount) were lower when D. magna fed with Synechococcus sp. than fed with R. minuta or S. acutus. Analysis of variance results show that carbon assimilation rates which were sum of incorporation and respiration rates and carbon growth efficiencies were only dependant on species affiliation. Overall, our results showed that algal species with varying ${\omega}3$ polyunsaturated fatty acid content led different carbon incorporation rates and overall carbon assimilation rates of D. magna.

• Carbon letters
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• v.8 no.2
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• pp.115-119
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• 2007

Properties of carbon blacks and carbon black/SBR rubber composites filled by surface modified carbon blacks were examined. Although the specific surface area of carbon blacks increased after the surface modifications with heat, acid, and base, there were no obvious changes in resistivity. The composites filled by heat treated carbon blacks showed a higher tensile strength and elongation than those filled by raw blacks. The acid and base treated carbon blacks filled composites also showed higher tensile strength but similar elongation values with those filled by raw blacks. With increasing loading ratio, both tensile strength and elongation increased, and appeared a maximum value at 30-40 phr. Modulus at 300% strain remained increasing with further loading of carbon blacks. At the same loading, the heat treated black filled composites showed similar modulus values with composites filled by raw blacks but for base and acid treated black filled composites much higher values were obtained. After the surface modification, the functional groups which played an important role in reinforcement action were changed.