• Proceedings of the Korean Magnestics Society Conference
• /
• 2007.05a
• /
• pp.120.1-120.1
• /
• 2007

• Transactions of the Korean hydrogen and new energy society
• /
• v.31 no.4
• /
• pp.380-386
• /
• 2020

This paper represents an analysis of the economic impact of firing natural gas/diesel and natural gas/by-product oil mixtures in diesel engine power plants. The objects of analysis is a power plant with electricity generation capacity (300 kW). Using performance data of original diesel engines, the fuel consumption characteristics of the duel fuel engines were simulated. Then, economic assessment was carried out using the performance data and the net present value method. A special focus was given to the evaluation of fuel cost saving when firing natural gas/diesel and natural gas/by-product oil mixtures instead of the pure diesel firing case. Analyses were performed by assuming fuel price changes in the market as well as by using current prices. The analysis results showed that co-firing of natural gas/diesel and natural gas/by-product oil would provide considerable fuel cost saving, leading to meaningful economic benefits.

• Journal of Sensor Science and Technology
• /
• v.29 no.2
• /
• pp.112-117
• /
• 2020

Xylene is a hazardous volatile organic compound that should be precisely measured to monitor indoor air quality. However, the selective and sensitive detection of ppm-level xylene using oxide-semiconductor gas sensors remains a challenge. In this study, pure and Cr-doped Co₃O₄ nanoparticles (NPs) were prepared using flame spray pyrolysis, and their gas-sensing characteristics to 5-ppm xylene at 250 ℃ were investigated. The 4 at% Cr-doped Co₃O₄ NPs exhibited a high gas response to 5-ppm xylene (resistance ratio to gas and air = 39.1) and negligible cross-responses to other representative and ubiquitous indoor pollutants such as ethanol, benzene, formaldehyde, carbon monoxide, and ammonia. In this paper, the enhancement of the gas response and selectivity of Co₃O₄ NPs to xylene by Cr doping was discussed in relation to the catalytic promotion of the gas-sensing reaction. This sensor can be used to monitor indoor xylene.

• 한국신재생에너지학회:학술대회논문집
• /
• 2008.05a
• /
• pp.491-494
• /
• 2008

The hydrogen fuel and fuel cell which have high energy efficiency and low pollutant emission are getting interest as an alternative energies due to the fossil fuel exhaust, green house effect and atmospheric pollutant problems. The hydrogen gas is very effective as an alternative energy. But, if it is leaked into the air it forms the mixed gas with the air then the danger of the explosion is risen up. So, the secure the safety is mostly important. In this research, to detect the leakage of the hydrogen rapidly, added the odorant materials which don't include the sulfur component into the hydrogen gas and researched on the effect of each odorant on the performance of the fuel cell. As the results, setting the cumulation electric power on the basis and comparing the pure hydrogen, 2,3-Butanedione 5ppm mixed gas 86.1%, 5-Ethylidene-2-Norbornene 17ppm mixed gas 88.2%, Isovaleraldehyde 10ppm mixed gas 74.8%, Ethyl Isobutyrate 2.2ppm mixed gas 93.5% of performance was shown.

• Journal of the Korean Institute of Gas
• /
• v.11 no.3
• /
• pp.33-39
• /
• 2007

In this study, the effect of reformer gas(RG) on the performance development of the exhaust gas recirculation(EGR) was investigated numerically in $CH_4/air$ premixed flame. Typically EGR is used to reduce the flame temperature and NOx emission, whereas RG can be used to improve the flame stability, such as homing velocity. This competitive relationship is focused in this study. As a result, it can be identified that the adjustments of EGR and RG ratio can achieve the low NOx emission and the similar flame stability to pure $CH_4/air$ premixed flame simultaneously.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.11 no.4
• /
• pp.288-292
• /
• 1998

In this paper, we fabricated $SnO_2$ composite ceramics doped with 0~20mol% $SnO_2$ of bulk type to investigate the CO and $H_2$ gas sensitivity in various composition, temperature, and concentration of CO and $H_2$ gas. At the temperature range from $100^{\circ}C\sim425^{\circ}C$, the measured 1000ppm and 250ppm CO gas sensitivities of $SiO_2-SnO_2$composite ceramics were about 1.0~7.6 and 1.0~5.6, respectively. These values were about 1.0~1.5 times larger than pure $SnO_2$. The maximum 1000ppm CO gas sensitivity of $SiO_2-SnO_2$composites were measured around $325^{\circ}C$. At the temperature range from $270^{\circ}C\sim380^{\circ}C$, the 1000ppm and 500ppm $H_2$gas sensitivities of $SiO_2-SnO_2$ composites were about 2.9~21.2 and 2.1~11.3, respectively. Also the maximum 1000, 500 ppm $H_2$ gas sensitivities of samples were measured around.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2008.03a
• /
• pp.589-596
• /
• 2008

Performance of a pulsed heat source high temperature inert gas plasma MHD electrical power generator, which can be one of the candidates of space-based laser-to-electrical power converter, is examined by a time dependent two dimensional numerical simulation. In the present MHD generator, the inert gas is assumed to be ideally heated to about $10^4K$ pulsed-likely within short time(${\sim}1{\mu}s$) in a stagnant energy input volume, and the energy of high temperature inert gas is converted to the electricity with the medium of pure inert gas plasma without seeding. The numerical simulation results show that an enthalpy extraction ratio(=electrical output energy/pulsed heat energy) of several tens of % can be achieved, which is the same level as the conventional seeded non-equilibrium plasma MHD generator. Although there still exist many phenomena to be clarified and many problems to be overcome in order to realize the system, the pulsed heat source high temperature inert gas MHD generator is surely worth examining in more detail.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.28 no.1
• /
• pp.45-52
• /
• 1992

In this paper, combustion characteristics and engine performance varying with blending rate of fish oil using five test fuels, e.g.pure diesel oil and four types of sardine-oil-blended diesel oils, their blending rates by weight being 20%, 40%, 60% and 80% respectively, and operating condition of engine, were investigated experimentally both in the constant volume combustion bomb and in the engine. The results are summarized as follows: 1) In the bomb, the influence of temperature on ignition delay of sardine-oil-blended diesel oils was larger than that of pure diesel oil, and it tended to increase as the blending rate of fish oil increase sardine-oil-blended diesel oils. As far as the influence of pressure on ignition delay concerns, there was no significant difference with all the test fuels. 2) In the engine, the ignition delay of fish-oil- blended diesel oils was longer than that of pure diesel oil, and it tended to increase as the blending rate increases. In the bomb, the ignition delay in high temperature showed no significant difference between with pure diesel oil and with fish-oil-blended diesel oils, and it was especially short with 60% fish-oil-blended diesel oil. In low temperature, however, the delay became longer as the blending rate increase. 3) The combustion duration was shorter with fish-oil-blended diesel oils than with pure diesel oil and it became a little shorter as the blending rate increases. 4) The rate of fuel consumption showed no significant difference between with fish-oil-blended diesel oils and with prue diesel oil, although calorific value of fish oil was lower than that of diesel oil. 5) Smoke density in exhaust gas was lower with fish-oil-blended diesel oils than with pure diesel oil and the higher the blending rate was, the lower the smoke density became.

• Resources Recycling
• /
• v.19 no.5
• /
• pp.3-12
• /
• 2010

Platinum group metals with high purity are important raw materials for high technology industry. Since there are no domestic ores containing PGMs, it is of importance to develop a separation process by which ultra pure PGMs can be recovered from diverse spent resources. Data on the chemical properties and dissolution behavior of PGMs were obtained from the literature. A method for the thermodynamic analysis of the HCl solution with chlorine gas was introduced. Utilizing the difference in the chemical properties and dissolution behavior of PGMs would lead to an efficient separation process to recover ultra pure PGMs.

• Korean Journal of Materials Research
• /
• v.12 no.8
• /
• pp.661-668
• /
• 2002

A study was made to examine the electrical, compositional, structural and morphological properties of Ag thin films deposited by DC magnetron sputtering in $O_2$ atmosphere with deposition temperature from room temperature to 15$0^{\circ}C$ using in-line sputter system. The Ag films deposited at temperature above $100^{\circ}C$ in oxygen atmosphere gave a similar specific resistivity to and even lower oxygen content than those deposited using pure Ar sputter gas The Ag films deposited with pure Ar gas was mainly composed of crystallites with [111] preferred orientation, while, for those deposited in oxygen atmosphere, more than 50% of the volume was composed of crystallites with [100] orientation. The difference in the micro structure did not cause any difference in the specific resistivity of Ag films. The results showed that the transparent conducting oxide films and the Ag films could be processed sequentially in the same deposition chamber with careful control of deposition temperature, which might result in a cost reduction for constructing the large scale in-line deposition system.