• Journal of Energy Engineering
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• v.17 no.4
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• pp.182-188
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• 2008

This paper is to compare the carbon-balanced and liner air-fuel ratio determination methods for alternative fuels. In the previous work, expansion of Eltinge chart, unburned hydrocarbon compensation, comparison of the results from various methods were discussed. It has been also concluded that Eltinge method might be regarded as the most general equation of AFR determination among the existing ones. In the recent years, however, increasing demand for the environmental preservation, including global warming-up protection, and energy conservation lead to introduce the alternative fuel to the internal combustion engine. Therefore, the exact calculations of AFR for these fuels are needed. Especially, for the fuel that contains oxygen, all AFR calculation equations except Eltinge have to be re-formulated. In this paper, the AFR for alternative fuel were calculated by re-formulated carbon balance, accuracy of which was already confirmed, and linear equations, which are newly proposed by statistical method for each fuel. The results show that AFRs based on carbon balance have a little more error compared with gasoline, however, the accuracy is enough for this formula to apply to various fuel. The proposed linear equation also have excellent accuracy below $\lambda=1.2$.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.14 no.1
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• pp.94-102
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• 2015

The high-pass(brand name of Electronic Toll Collection System) utilization trend on the highway continues to grow as 59.4% (by the end of 2013). In this study, we applied the carbon balance method using a fuel chassis dynamometer with the four passenger car classes in order to measure the fuel consumption of the car using the expressway tollgate. We experimented 18 driving mode at general tollgate and high-pass tollgate. As a result, in case of entry/exit toll there were 21.0~56.4ml/veh fuel consumption savings, in case of open toll fuel consumption savings was analyzed as 10.5~28.1ml/veh. In addition, the annual fuel cost savings by virtue of high-pass was 28.2~57.3 billion won at 70% utilization rate, 32.2~65.5 billion won at 80%, 36.2~73.7 billion won at 90% and 40.3~81.9 billion won at 100%.

• Journal of Institute of Convergence Technology
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• v.3 no.2
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• pp.57-60
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• 2013

The purpose of this study is to analysis of how to calculate fuel efficiency in major development countries (U.S. and Europe) and energy consumption formular derivation of domestic CNG fuel and prove by vehicle test. The formula of fuel consumption is different in mpg(mile per gallon), l/100km, and km/l each countries. CNG fuel has a significant impact on fuel density, composition, and Hydro-Carbon ratio. So, this study how to measurement and calculation procedures of CNG gaseous fueled vehicle energy consumption rate.

• Journal of Life Science
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• v.25 no.11
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• pp.1290-1297
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• 2015

Studies of the inactivation of a gene encoding pyruvate decarboxylase, pdc, in an ethanol-producing bacterium, Zymomonas mobilis, identified a mutant strain with 50% reduced PDC activity. To evaluate the possibility of a carbon-flux shift from an ethanol pathway toward higher value fermentation products, including pyruvate, succinate, and lactate, fermentation studies were carried out. Despite attempts to silence pdc expression in the wild-type strain ZM4 using cat-inserted pdc and pdc-deleted homologs by electroporation, the strain isolated showed partial gene activation. Fermentation experiments with the PDC mutant strain showed that the reduced expression level of PDC activity resulted in decreased rates of substrate uptake and ethanol production, together with increased pyruvate accumulation of 2.5 g l^-1 , although lactate and succinate concentrations were not significantly enhanced in these modified strains. Despite numerous attempts, no strains were isolated in which complete pdc inactivation occurred. This result indicates that the ethanol fermentation pathway of this bacterium is totally dependent on the activity of the PDC enzyme. To ensure a redox balance of intracellular NAD and NADH levels, other enzymes, such as lactate dehydrogenase for lactate, and enzymes involved in the production of succinic acid, such as pyruvate dehydrogenase (PDH) and malic enzymes, may be needed for their increased end-product production.

• Journal of Technology Innovation
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• v.31 no.1
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• pp.29-63
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• 2023

The purpose of this study is to analyze the process of changes in regional science and technology policies in Korea and to seek future development directions. In Korea, regional science and technology policies have been implemented since the introduction of the local autonomy system. Since then, it has been implemented in earnest with the establishment of a central government-level plan. The regional science and technology policies have been developed to this day by interacting with national science and technology policies and regional development policies. Nevertheless, due to the path dependence and lock-in effect in the accumulated process, the regional science and technology policies are still subordinate to central government policies. Thus, the establishment of an independent ecosystem for local science and technology is still insufficient. Furthermore, the gap between regions is deepening, such as the growing of aging population, population decline due to low birth rates, job losses due to the recession of local key industry, and the concentration of the youth population in the metropolitan area. The transformation path such as digital transformation and carbon neutrality paradigm is expected to further widen regional disparities. In order to address a comprehensive problem, the implementing system of regional science and technology policies need to be newly established. A framework for reinvention of regional science and technology policy needed in the era of grand societal challenges have to be developed.