• Korean Journal of Medicinal Crop Science
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• v.9 no.3
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• pp.232-237
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• 2001

This study was carried out to know the effect of light intensity, temperature and $CO_2$ concentration on photosynthesis and transpiration in yacon(Polymnia sonchifolia Poepp.& Endl.). Light compensation point was ${58\;{\mu}mol\;m^{-2}\;s^{-1}}$and light saturation point was ${1708\;{\mu}mol\;m^{-2}\;s^{-1}}$. Transpiration rate was increased to about 4 mmol${m^{-2}\;s^{-1}}$ with increasing of light intensity to ${2193\;{\mu}mol\;m^{-2}\;s^{-1}}$. The optimum temperature for photosynthesis was ${24^{\circ}C}$ in air. Photosynthesis was gradually reduced as transpiration rate increased from 4 to 8 mmol ${m^{-2}\;s^{-1}}$ in different air temperature. $CO_2$ compensation point was 63 vpm and $CO_2$ saturation point was 1155 vpm and light saturation point was enhanced with increasing of $CO_2$ concentration from 350 vpm to 1300 vpm.

• KSBB Journal
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• v.11 no.3
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• pp.295-302
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• 1996

The measurements of rubisco parameters are important in photosynthetic studies. In this experiment, we used photometric assay method to detect these major parameters, such as activity, carbamylation and amount of rubisco. The main advantages of this method are very simple and as sensitive as conventional methods which usually produce radioactive waste. In this study, with kidney bean (Phaseolus vulgatis L.) leaves grown at normal $CO_2$ (350ppm) and high $CO_2$ (650 ppm), we investigated the effect of $CO_2$ concentration on activation and carbamylation of rubisco by measuring the rubisco activity, carbamylation rate and amount of rubisco using a dual beam (334nm and 405nm) spectrophotometer, and analyzed the polypeptide profiles of rubisco by SDS-PAGE. When $CO_2$ concentration was raised from 350ppm to 650ppm, all parameters of rubisco were decreased : $41.2{\mu}M/m^2/s and 52.2{\mu}M/m^2/s$ to $27.4{\mu}M/m^2/s and 46.1{\mu}M/m^2/s$ for initial and total rubisco activity, respectively ; from 79% to 58.9% for carbamylation rate ; from $1.94 {\mu}M/m^2$ to 1.58{\mu}M/m^2$ for amount of rubisco. These results suggests that the decrease in rubisco activity at high $CO_2$ was caused by carbamylation. The analysis of the preparation by SDS-PAGE showed two major polypeptides at 50 and 14.5 kD which were identified as the large and the small subunits of rubisco. There were no differences in the intensity compared high $CO_2$ to normal $CO_2$ in both 50 kD and 14.5 kD bands. We also found that these inhibitory effects of $CO_2$ were reversible. When high $CO_2$ was switched to normal $CO_2$, the parameters of rubisco changed were almost the same as normal rubisco parameters. These data provide an evidence that activity of rubisco was recovered by $CO_2$ concentration of 350 ppm.

• Journal of Energy Engineering
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• v.22 no.4
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• pp.347-354
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• 2013

This study was carried out to examine different mole ratio of $H_2/CO_2$ and EBCT using the continuous system in the lab scale throughout biological methods with accumulated hydrogenotrophic methanogen that can convert $CO_2$ to $CH_4$. The experimental-based results with various gas mixtures of mole ratio of 4:1($H_2/CO_2$) and 5:1($H_2/CO_2$), $H_2$ was converted more than 99% conversion rate. In case of $CO_2$, 4:1($H_2/CO_2$) and 5:1($H_2/CO_2$) were $74.45{\pm}0.33%$, $95.8{\pm}10.7%$, respectively, in addition, the study was confirmed that the amount of $H_2$ was more needed than stoichiometric equations, where approach methods are empirical versus theoretical frameworks, for converting total $CO_2$. As such, we have noticed that $H_2$ was used for energy source of hydrogenotrophic methanogen for maintaining life. Regarding the results of the ratio of treatment by retention time, limitation of treatment capacity showed that $H_2$(99.9%) and $CO_2$(96.23%) at EBCT 3.3 hrs indicated stable conversion ratio, as well as appeared that methane production rate and $CO_2$ fixation rate were investigated $1.15{\pm}0.02m^3{\cdot}m^{-3}{\cdot}day^{-1}$ and $2.01{\pm}0.04kg{\cdot}m^{-3}{\cdot}day^{-1}$, respectively.

• Journal of Bio-Environment Control
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• v.30 no.4
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• pp.401-409
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• 2021

This study aimed to estimate the photosynthetic capacity of tomato plants grown in a semi-closed greenhouse using temperature response models of plant photosynthesis by calculating the ribulose 1,5-bisphosphate carboxylase/oxygenase maximum carboxylation rate (V_cmax), maximum electron transport rate (J_max), thermal breakdown (high-temperature inhibition), and leaf respiration to predict the optimal conditions of the CO₂-controlled greenhouse, for maximizing the photosynthetic rate. Gas exchange measurements for the A-C_i curve response to CO₂ level with different light intensities {PAR (Photosynthetically Active Radiation) 200µmol·m^-2·s^-1 to 1500µmol·m^-2·s^-1} and leaf temperatures (20℃ to 35℃) were conducted with a portable infrared gas analyzer system. Arrhenius function, net CO₂ assimilation (A_n), thermal breakdown, and daylight leaf respiration (R_d) were also calculated using the modeling equation. Estimated J_max, A_n, Arrhenius function value, and thermal breakdown decreased in response to increased leaf temperature (> 30℃), and the optimum leaf temperature for the estimated J_max was 30℃. The CO₂ saturation point of the fifth leaf from the apical region was reached at 600ppm for 200 and 400µmol·m^-2·s^-1 of PAR, at 800ppm for 600 and 800µmol·m^-2·s^-1 of PAR, at 1000ppm for 1000µmol of PAR, and at 1500ppm for 1200 and 1500µmol·m^-2·s^-1 of PAR levels. The results suggest that the optimal conditions of CO₂ concentration can be determined, using the photosynthetic model equation, to improve the photosynthetic rates of fruit vegetables grown in greenhouses.

• Journal of Hydrogen and New Energy
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• v.17 no.4
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• pp.362-370
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• 2006

The purpose of this paper was to investigate the reforming characteristics and optimum operating condition of the plasmatron assisted $CH_4$ reforming reaction for the hydrogen-rich gas production. Also, in order to increase the hydrogen production and the methane conversion rate, parametric screening studies were conducted, in which there were the variations of the $CH_4$ flow ratio, $CO_2$ flow ratio, vapor flow ratio, mixing flow ratio and catalyst addition in reactor. High temperature plasma flame was generated by air and arc discharge. The air flow rate and input electric power were fixed 5.1 l/min and 6.4 kW, respectively. When the $CH_4$ flow ratio was 38.5%, the production of hydrogen was maximized and optimal methane conversion rate was 99.2%. Under these optimal conditions, the following synthesis gas concentrations were determined: $H_2$, 45.4%; CO, 6.9%; $CO_2$, 1.5%; and $C_2H_2$, 1.1%. The $H_2/CO$ ratio was 6.6, hydrogen yield was 78.8% and energy conversion rate was 63.6%.

• Asian Journal of Atmospheric Environment
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• v.6 no.2
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• pp.104-110
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• 2012

We studied the effects of elevated ozone ([$O_3$]) and $CO_2$ concentrations ([$CO_2$]) on the growth and photosynthesis of the hybrid larch $F_1(F_1)$ and on its parents (the Dahurian larch and Japanese larch). $F_1$ is a promising species for timber production in northeast Asia. Seedlings of the three species were grown in 16 open top chambers and were exposed to two levels of $O_3$ (<10 ppb and 60 ppb for 7 h per day) in combination with two levels of $CO_2$ (ambient and 600 ppm for daytime) over an entire growing season. Ozone reduced the growth as measured by height and diameter, and reduced the needle dry mass and net photosynthetic rate of $F_1$, but had almost no effect on the Dahurian larch or Japanese larch. There was a significant increase in whole-plant dry mass induced by elevated [$CO_2$] in $F_1$ but not in the other two species. Photosynthetic acclimation to elevated [$CO_2$] was observed in all species. The net photosynthetic rate measured at the growing [$CO_2$] (i.e. 380 ppm for ambient treatment and 600 ppm for elevated $CO_2$ treatment) was nevertheless greater in the seedlings of all species grown at elevated [$CO_2$]. The high [$CO_2$] partly compensated for the reduction of stem diameter growth of $F_1$ at high [$O_3$]; no similar trend was found in the other growth and photosynthetic parameters, or in the other species.

• Particle and aerosol research
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• v.10 no.2
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• pp.75-82
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• 2014

It is necessary to find out the reaction characteristics of $CaCO_3$ sorbent particles in air and $O_2/CO_2$ atmospheric conditions in order that an in-furnace desulfurization technique can be applied to oxy-fuel combustion system. In this study, rate of change of GMD(geometric mean diameter) and specific surface area of $CaCO_3$ sorbent particles reacted in DTF(drop tube furnace) experimental setup were analyzed to investigate the effect of particle size and humidity on the reaction characteristics of them. In air atmospheric condition, calcination process occurs actively within shorter residence times as the particle size increases. On the contrary, in $O_2/CO_2$ atmospheric condition, a calcination process is delayed as particle size increases. The increment of humidity accelerates calcination process in an air atmospheric condition and increase rate of calcination in an $O_2/CO_2$ atmospheric condition.

• Fire Science and Engineering
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• v.24 no.3
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• pp.86-92
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• 2010

One of the limitation of wood as building materials is its flammability. The purpose of this paper is to examine the combustion properties of the Pinus rigida and Castanea savita which are grown in Korea and meet the desirable characteristics for use of construction materials. The cone calorimeter (ISO 5660-1) was used to determine the heat release rate (HRR) and fire smoke index, as well as CO and $CO_2$ production and smoke obscuration. The $HRR_{mean}$ of the Castanea savita and Pinus rigida at $50\;kW/m^2$ of radiant heat flux was $70.4\;kW/m^2$ and $68.5\;kW/m^2$. Furthermore, the THR of Castanea sativata was 120.8 MJ/kg and it was higher than the THR of Pinus rigida ($81.9\;MJ/m^$). These results are depend on the bulk density of tested wood species. The Castanea savita has high $CO_{mean}$ yield and high CO/$CO_2$ yield compared with that of Pinus rigida.

• Korean Journal of Microbiology
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• v.21 no.1
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• pp.27-35
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• 1983

The stoichiometry between the consumption of CO and $O_2$ and the production of $CO_2(2CO+O_2{\rightarrow}2CO_2)$) showed that Pseudomonas carboxydohydrogena grows as a typical aerobic CO oxidizer with CO. The optimal concentration of CO for growth was found to be 30% in gas mixture with air. The initial buffer concentration of the culture medium did not affect the growth of this bacterium. P. carboxydohydrogena is an obligate aerobe and dose not use nitrate as a terminal electron acceptor. The CO dehydrogenase is an inducible and soluble enzyme. The reaction rate and stability were maximal at pH7.5, and the Arrhenius plot revealed an activation energy of 37.7kJ/mol (9.0 Kcal/mol). The crude enzyme used methylene blue, thionin, and toluylene blue as electron acceptors for the oxidation of CO to $Co_2$ under anaerobic conditions. It was found that water must be the source of the second oxygen atom for CO oxidation.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• v.1 no.1
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• pp.51-59
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• 1997

Two comparative poplar clones (I-214: Populus euramericana, Peace: P koreana x P. trichocarpa) were exposed to two $CO_2$ concentrations (350 or 2,000 ${\mu}L\;L^{-1}\;CO_2)$ for 21 days. When both poplar clones were compared at growth conditions, the net photosynthetic rate $(P_N)$ in $CO_2-enriched$ (2,000 ${\mu}L\;L^{-1}\;CO_2=C_{2,000})$ plants become about $50-60\%$ higher than that of 350 ${\mu}L\;L^{-1}\;CO_2(=C_{350})$ plants on 7 days treatment. But the enhancement of $P_N$ by high $CO_2$ was not maintained throughout all the experimental period. At 21 days, there was no difference of photosynthetic rates between $C_{350}\;and\;C_{2,000}$ plants. In contrast with photosynthesis, the response of leaf conductance to the elevated $CO_2$ concentration was very different between I-214 and Peace. During all experimental period, leaf conductance $(g_s)$ of $C_{2,000}$ plants is $50\%$ lower than that of the $C_{350}$ plants for I-214, while there is no difference of $g_s$ between the plants of $C_{350}\;and\;C_{2,000}$ on for Peace. The results of gs in Peace indicate that decreased photosynthetic rate after 21 days in $C_{2,000}$ on plants for two poplar clones is possibly due to non-stomatal factors. To investigate the non-stomatal factors, starch accumulation and ribulose-1,6-bisphosphate carboxylase (RuBPCase) were measured. We found significant accumulation of starch in two poplar clones exposed to high $CO_2,$ especially starch of I-214 in $C_{2,000}$ become 3.5 times higher than in $C_{350}$ plants at 21 days. This suggests that high proportion of photosynthates was directed into starch. After 21 days, the activity of ribulose-1, 6-bisphosphate carboxylase of $C_{2,000}$ plants become decreased in $40-50\%$ compared with that of the $C_{350}$ plants. Two poplar clones show the same trend to RuBPCase declines under high $CO_2$ concentration, although the decline is more significant for I-214. The results reported here suggest that starch accumulation and decreased RuBPCase activity in $C_{2,000}$ plants can be partly ascribed to the loss of photosynthetic efficiency of high $CO_2-grown$ poplar plants.