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Cheongju, South Korea

Chungbuk National University is one of ten Flagship Korean National Universities. It takes its name, Chungbuk, from the common abbreviated form of the province's Korean name. Wikipedia.

Ammonia-oxidizing archaea (AOA) typically predominate over ammonia-oxidizing bacteria in marine sediments. We herein present the draft genome sequence of an ammonia-oxidizing archaeon, "Candidatus Nitrosopumilus sediminis" AR2, which was enriched in culture from a marine sediment obtained off Svalbard, within the Arctic Circle. The typical genes involved in archaeal ammonia oxidation and carbon fixation necessary for chemolithoautotrophic growth were observed. Interestingly, the AR2 genome sequence was revealed to possess, uniquely among cultivated AOA from marine environments, a capability for urea utilization.

Kwon O.M.,Chungbuk National University
International Journal of Robust and Nonlinear Control | Year: 2011

In this paper, the problem of delay-dependent stability for uncertain stochastic dynamic systems with time-varying delay is considered. Based on the Lyapunov stability theory, improved delay-dependent stability criteria for the system are established in terms of linear matrix inequalities. Three numerical examples are given to show the effectiveness of the proposed method. © 2010 John Wiley & Sons, Ltd.

No S.-Y.,Chungbuk National University
Renewable and Sustainable Energy Reviews | Year: 2014

This review will be concentrated on the application of bio-oil produced from the cellulosic biomass among the various liquid biofuels to transport fuels, heat and power generation as substitute. Main application of bio-oil and biocrude from two main thermochemical processes, i.e., pyrolysis and liquefaction include boiler for heat and electricity production, diesel engine or gas turbine for power generation, and diesel engine for transportation fuel. Fast pyrolysis is the most popular process for converting cellulosic biomass to high yield of bio-oil with relatively low cost. For the application of bio-oils to transportation, heat and power generation, physical upgrading methods such as emulsions (bio-oil/diesel or bio-oil/biodiesel) and blends of bio-oil/oxygenated fuel (ethanol, diglyme) were mainly used and tested. The studies on the spray characteristics of emulsions and blends in diesel engine condition are not available in the literature. In most studies on the combustion and emission characteristics of emulsions and blends, CO emission was increased in most fuels and engines tested and HC was increased or comparable to diesel operation. However, NOx and soot emissions were decreased in most case of experiments. In the pressure-swirl nozzle for gas turbine application, preheating and blending techniques were employed to reduce the SMD of spray. In case of blend for the application of heat and power generation, E20 blend was mainly selected in most studies. Most studies related to bio-oil combustion in burners, diesel engines and gas turbines demonstrated the higher HC, CO and soot emissions than the original design fuel. Although the properties of bio-oil/methanol blend were widely investigated, there are no studies available about the application of bio-oil/methanol blend to transportation, heat and power generation in the literature. In addition, more research is required for the combustion of upgraded bio-oils for transportation application. © 2014 Elsevier Ltd.

This review will be concentrated on the application of hydrotreated vegetable oils (HVO) produced from the triglycerides based biomass such as vegetable oil, animal fat, waste cooking oil and algae to compression ignition (CI) engines. Main problem in the application of HVO to CI engines is the poor low-temperature properties. The upgrading technology of cold flow properties of HVO reported in the literature can be categorized with four ways as isomerization, addition of flow improver, reaction temperature control and co-processing with petroleum derived raw materials. The advantages of hydrotreating over transesterification are lower processing cost, compatibility with infrastructure, NOx emission reduction, and feedstock flexibility. Combustion and emission characteristics of neat HVO, blends of HVO with petrodiesel and HVO with additives were widely investigated by many researchers. The use of HVO enables appreciable reductions in NOx, PM, HC and CO emissions without any changes to the engine or its control in heavy-duty engines. HVO could play an important role in providing an sustainable source of transportation fuels during the coming decades. In addition, HVO obtained from inedible vegetable oil and application of it to CI engine will be the subjects of future research in the production and application of HVO. The technologies for the reduction of NOx and PM in CI engines fuelled with HVO can be categorized with engine optimization and fuel optimization. The engine optimization technology is more effective than the fuel optimization technology. © 2013 Elsevier Ltd. All rights reserved.

No S.-Y.,Chungbuk National University
Renewable and Sustainable Energy Reviews | Year: 2011

The use of inedible vegetable oils as an alternative fuel for diesel engine is accelerated by the energy crisis due to depletion of resources and increased environmental problems including the great need for edible oil as food and the reduction of biodiesel production cost, etc. Of a lot of inedible vegetable oils which can be exploited for substitute fuel as diesel fuel, seven vegetable oils, i.e., jatropha, karanja, mahua, linseed, rubber seed, cottonseed and neem oils were selected for discussion in this review paper. The application of jatropha oil as a liquid fuel for CI engine can be classified with neat jatropha oil, engine modifications such as preheating, and dual fuelling, and fuel modifications such as jatropha oil blends with other fuels, mostly with diesel fuel, biodiesel, biodiesel blends and degumming. Therefore, jatropha oil is a leading candidate for the commercialization of non-edible vegetable oils. There exists a big difference in the fuel properties of seven inedible vegetable oils and its biodiesels considered in this review. It is clear from this review that biodiesel generally causes an increase in NOx emission and a decrease in HC, CO and PM emissions compared to diesel. It was reported that a diesel engine without any modification would run successfully on a blend of 20% vegetable oil and 80% diesel fuel without damage to engine parts. This trend can be applied to the biodiesel blends even though particular biodiesel shows 40% blend. In addition, the blends of biodiesel and diesel can replace the diesel fuel up to 10% by volume for running common rail direct injection system without any durability problems. © 2010 Elsevier Ltd.

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