• Transactions of the Korean hydrogen and new energy society
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• v.25 no.5
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• pp.482-490
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• 2014

Gaseous sulfur compound such as $H_2S$ or COS in coal- or biomass-derived hot syngas can be purified by solid sorbents at high temperatures. In this study, we investigated the physical properties and reactivity of solid regenerable desulfurization sorbents with 37.2, 41.9, and 46.5wt% ZnO to look into the ZnO content effect. The sorbents were produced by spray-drying method to apply to a fluidized-bed process. Sulfidation and regeneration reaction were carried out using a thermogravimetric analyzer. Sorbent prepared with 46.5wt% ZnO had physical properties suitable for a fluidized-bed process applications such as spherical shape, sufficient mechanical strength and density, high porosity and surface area. It showed high sulfur sorption capacity of 10.4wt% (ZnO utilization of 57%) at reaction temperatures of 500 and $650^{\circ}C$ for sulfidation and regeneration, respectively. However, the sulfur sorption capacity and ZnO utilization were significantly reduced and dimple shape appeared when the ZnO content decreased to 37.2 and 41.9wt%. Sulfur sorption capacity and regenerability were improved as reaction temperature increased within the experimental temperatures used in this work. The reaction temperature zones of $1500{\sim}550^{\circ}C$ and $650{\sim}700^{\circ}C$ are recommended for sulfidation and regeneration, respectively, to lead best reaction performances of the ZnO-based spray-dried sorbents developed in this work.

• Journal of Institute of Convergence Technology
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• v.1 no.2
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• pp.37-42
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• 2011

The purpose of this research is to improve nitrogen removal efficiency in winter season through rise of water temperature of extraneous water by using solar energy which is estimated to have great potential among new regeneration energy and while operating Plug-Flow Reactor to improve nitrogen removal efficiency by selecting A/O process among sewage waste water treatment processes as the necessity of solving the problem of nitrogen removal efficiency according to reduced water temperature in winter season and strengthening of water quality criteria regarding discharged sewage waste water suggested in the research background. Summarizing the research result, supply of solar energy source improves the function outstandingly when removing nitrogen, (nitrogen removal rate before operating solar energy 55.4% ${\rightarrow}$ nitrogen removal rate after operating solar energy 84.1%).

• Transactions of the Korean hydrogen and new energy society
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• v.28 no.4
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• pp.361-368
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• 2017

Alanate-based materials, which were known to have high hydrogen storage capacity, were synthesized by mechanochemically metathesis reaction of metal chloride and sodium alanate without solvent. XRD patterns of synthesized materials showed that metathesis reaction of cations between metal chloride and sodium alanate was progressed favorably without any solvent. Magnesium alanate showed that 3.2 wt.% of hydrogen was evolved by the thermal decomposition. The addition of a small amount of Ti to the magnesium alanate greatly reduced hydrogen evolution temperature. Also, Ti doped magnesium alanate had a good regeneration property. Both the calcium and lithium-magnesium alanate showed the lower starting temperature of the two step hydrogen evolution and fast kinetics for the hydrogen evolution.

• Transactions of the Korean hydrogen and new energy society
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• v.26 no.4
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• pp.377-385
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• 2015

This paper presents a thermodynamic performance analysis of regenerative organic Rankine cycle (ORC) using turbine bleeding to utilize low-grade finite thermal energy. Refrigerant R245fa was selected as the working fluid. Special attention is paid to the effects of the turbine bleeding pressure and the turbine bleed fraction on the thermodynamic performance of the system such as net power production and thermal efficiency. Results show that the thermal efficiency has an optimum value with respect to the turbine bleeding pressure and the net power production is lower than the basic ORC while the thermal efficiency is higher.

• Horticultural Science & Technology
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• v.31 no.3
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• pp.359-365
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• 2013

Chrysanthemum is one of the most popular ornamental plants worldwide. Recently, lots of new and novel chrysanthemum varieties have been developed using mutagenesis. However, there was no study for comparison of tissue culture condition among the mutant varieties derived from one original variety, until now. This study was conducted to compare the efficient regeneration condition of the two chrysanthemum mutant varieties, 'ARTI-purple' and 'ARTI-queen'. Two different flower parts (disk and ray florets) at the unopened and early blooming stages were used for comparison of regeneration condition on MS medium supplemented with combinations of three growth regulators (BA, NAA, and IAA). The highest regeneration rate was identified on the NAA and BA combination when the disk florets at unopened blooming stage are used. The best optimum combinations of growth regulators were identified as NAA $1.0mg{\cdot}L^{-1}$ and BA $0.5mg{\cdot}L^{-1}$ at 'ARTI-purple', which displayed 47.9% regeneration. However, regeneration of 'ARTI-queen' was the highest as 25.6% at NAA $2.0mg{\cdot}L^{-1}$ and BA $1.0mg{\cdot}L^{-1}$. There results indicate that there is a difference for the optimum regeneration condition between the mutant varieties derived from one original variety. These results will be useful for construction of efficient regeneration system of diverse chrysanthemum mutants developed by mutation breeding.

• Journal of Radiation Industry
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• v.5 no.3
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• pp.231-236
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• 2011

'Ggoma' is a new Hibiscus dwarf type variety developed by gamma irradiation at the Korea Atomic Energy Research Institute (KAERI). This study was conducted to determine the best optimum cultural callus formation and shoot regeneration condition. Sterilized leaf tissues were cultured on MS (Marashige and skoog's) medium containing 3% sucrose, 0.8% agar with different concentration and combination of TDZ, 2, 4-D, KT, BA, and 2iP for 4 weeks in vitro culture. MS medium containing 2,4-D $0.1mg\;l^{-1}$ and BA $0.5mg\;l^{-1}$ were most effective on callus formation and growth. After 4 weeks, callus was transferred on BA (0.5, 1, $1.5mg\;l^{-1}$) and TDZ (0.1, 0.2, $0.3mg\;l^{-1}$) for shoot formation. The best condition for inducing the shoot from callus was BA $1.5mg\;l^{-1}$ and TDZ $0.3mg\;l^{-1}$. This result will be useful for the rapid multiplication of Hibiscus syriacus L.var. Ggoma.

• Transactions of the Korean hydrogen and new energy society
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• v.23 no.1
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• pp.83-92
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• 2012

Syngas combustion characteristics of mass produced oxygen carrier particle (OCN706-1100) were investigated in a pressurized fluidized bed reactor using simulated syngas and air as reactants for reduction and oxidation, respectively. The oxygen carrier showed high fuel conversion, high $CO_2$ selectivity, and low CO concentration at reduction conditions and no NO emission at oxidation conditions. Moreover, OCN706-1100 particle showed good regeneration ability during successive reduction-oxidation cyclic tests up to the 10th cycle. Fuel conversion and $CO_2$ selectivity decreased and CO emission increased as temperature increased. These results can be explained by trend of calculated equilibrium CO concentration with temperature. However, fuel conversion and $CO_2$ selectivity increased and CO emission decreased as pressure and gas residence time increased.

• Transactions of the Korean hydrogen and new energy society
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• v.23 no.2
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• pp.173-182
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• 2012

Effects of temperature, pressure, and gas residence time on methane combustion characteristics of mass produced oxygen carrier particle (OCN706-1100) were investigated in a pressurized fluidized bed reactor using methane and air as reactants for reduction and oxidation, respectively. The oxygen carrier showed high fuel conversion, high $CO_2$ selectivity, and low CO concentration at reduction condition and very low NO emission at oxidation condition. Moreover OCN706-1100 particle showed good regeneration ability during successive reduction-oxidation cyclic tests up to the 10th cycle. Fuel conversion and $CO_2$ selectivity decreased and CO emission increased as temperature increased. These results can be explained by trend of calculated equilibrium CO concentration. However, $CO_2$ selectivity increased as pressure increased and fuel conversion increased as gas residence time increased.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.28 no.4
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• pp.158-164
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• 2016

Currently, identifying a new carbon-free energy resource is important in order to resolve the global warming problem. Along the same line, this paper studied how to convert magnetic force into mechanical force and a new basic mechanism of converting magnetic force into mechanical force was identified. Long-term reliability test, around 15 million times, was also conducted at $-1^{\circ}C{\sim}27^{\circ}C$ to evaluate the durability of magnetic force. As a result, tests showed that the deviation of the mechanical force was within 0.8% of the initial force, and the relation between repulsive force (P) and ambient temperature (T) was formulated in a linear equation P = -0.175T+78.945.

• Journal of Plant Biotechnology
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• v.40 no.4
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• pp.185-191
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• 2013

Over the past decades, carbon dioxide concentration of the atmosphere of the world has increased significantly, and thereby the greenhouse effect has become a social issue. To solve this problem, new renewable energy sources including solar, hydrogen, geothermal, wind and bio-energy are suggested as alternatives. Among these new energy sources, bio-energy crops are widely introduced and under rapid progress. For example, corn and oilseed rape plants are used for the production of bio-ethanol and bio-diesel, respectively. However, grain prices has increased severely because of the use of corn for bio-ethanol production. Therefore, non-edible switchgrass draws attention as an alternative source for bio-ethanol production in USA. This review describes the shortage of fossil energy and an importance of switchgrass as a bio-energy crop. Also, some characteristics of its major cultivars are introduced including growth habit, total output of biomass yields. Furthermore, biotechnological approaches have been conducted to improve the productivity of switchgrass using tissue culture and genetic transformation.