• Journal of Microbiology and Biotechnology
• /
• v.14 no.3
• /
• pp.532-539
• /
• 2004

For efficient lincomycin production from Streptomyces lincolnensis L1245, various vegetable oils, natural nitrogen sources, and surfactants were investigated at the pilot-scale level in the flask. Olive oil as the sole carbon source was the most suitable one for producing lincomycin. When 20 g/lof olive oil was used, the lincomycin concentration and lipase activity reached 1.01 g/land 182 U/ml, respectively, after 5 days of culture. Among the various unsaturated fatty acids, when linolenic acid was used, the cell growth and lincomycin production were markedly decreased. On the other hand, when 0.2 g/l of oleic acid was added to the culture broth, the maximum lincomycin concentration was 1.0 g/l, which was about 1.7-fold higher than that obtained without the addition of oleic acid. Among the various natural nitrogen sources, pharmamedia or soybean meal was the most suitable nitrogen source. In particular, in the case of a mixture of 10 g/l of pharmamedia and soybean meal, 1.5 g/l of lincomycin concentration and 220 U/ml of lipase activity were obtained. When Span 180 was used as the surfactant, lincomycin production, lipase activity, and oil consumption increased. The correlation between the consumption rates of oil and lincomycin production in a culture using olive oil as the sole carbon source was also investigated. The lincomycin production depended on the consumption rate of olive oil. Using these results, fed-batch cultures for comparing the use of olive oil and starch as a conventional carbon source were carried out in a 5-1 fermentor. When olive oil was used as the sole carbon source, 34 g/l of olive oil was consumed after 7 days of culture. The maximum lincomycin concentration was 3.0 g/l, which was about 2.0-fold higher than that of starch medium after 7 days of culture. The product yield was 0.09 gig of consumed carbon source, which was about 3.0-fold higher than that of starch medium after 7 days of culture.

• Environmental and Resource Economics Review
• /
• v.20 no.2
• /
• pp.335-356
• /
• 2011

In this paper, we attempted to suggest a way to evaluate appropriateness and efficiency for the energy consumption structure. For this, based on Markowitz (1952)' mean-variance portfolio model, we constructed an optimal fossil fuel mix. In constructing the optimal mix, we first defined returns on fossil fuels (oil, coal and natural gas) as TOE (Ton of Oil Equivalent) per $1. Then, by using the dynamic latent common factor model, we decomposed the growth rates of the returns on each fossil fuel into two parts : the common part and the idiosyncratic part. Finally, based on the results from the dynamic latent common factor model, we constructed the optimal fossil fuel mix implied by the mean-variance portfolio model. Our results indicate that for the fossil fuel mix to be on the efficient frontier, it is crucial to reduce oil consumption as low as possible. Moreover, our results imply that it is more efficient to increase natural gas consumption rather than coal consumption in reducing oil consumption. These results are in line with the strategies for the future energy consumption structure pursued by Korea and indicate that reduction in oil use can improve overall efficiency in energy consumption.

• Journal of Power System Engineering
• /
• v.19 no.2
• /
• pp.90-95
• /
• 2015

Recently worldwide concern and research is being actively conducted on green energy which can reduce environmental pollution. A plant such as the natural rapeseed oil, soybean oil, palm, etc. is used as a bio source in home and industry. Biofuels is a sustainable fuel having economically benefits and decreasing environmental pollution problems caused due to fossil fuel, and it can be applied to the conventional diesel engine without changing the existing institutional structure. Waste vegetable oil contains a high cetane number and viscosity component, the low carbon and oxygen content. A lot of research is progressing about the conversion of waste vegetable oil as renewable clean energy. In this study, waste oil was prepared to waste cooking oil generated from the living environment, and applied to diesel engine to confirm the possibility and cost-effectiveness of biodiesel blend waste oil. As a result, brake specific fuel consumption and NOx was increased, carbon monoxide and soot was decreased.

• Tribology and Lubricants
• /
• v.14 no.3
• /
• pp.51-58
• /
• 1998

This paper considers analysis of the lubrication between the piston ring and the cylinder liner. Piston ring lubrication analysis considering oil transport is important because oil consumption is an essential factor to design the piston assembly. To develop the lubrication analysis program for the piston ring, oil continuity condition and open-end boundary assumption are used for computational boundaries. Results show that oil continuity can be almost satisfied at any crank angle in and out of the piston ring clearance. Therefore the amount of oil consumption and the dynamic behavior of ring pack can be estimated using this algorithm. And it can be known that the effective width may be smaller than the full width of the piston ring, so oil starvation condition should be considered for the lubrication analysis of the piston ring.

• Journal of Biosystems Engineering
• /
• v.10 no.2
• /
• pp.47-54
• /
• 1985

Performance of a screw press was investigated experimentally with soybeans of various temperatures in order to find out a proper temperature of soybean to extract the oil by the mechanical method. Crude oil extracted by the screw press was chemically analyzed to determine a level of processing the oil for the oil to be used as a fuel for a compression ignition engine. The crude oil was degummed and dried by a plant type laboratory experimental setup to decide whether the processes are effective to improve quality of the oil as a fuel. The degummed oil and the degummed and dried oil were also chemically analyzed and were compared with the crude oil and the commercially degummed and dried soybean oil. The results are as follows: 1. In extraction of soybean oil by a screw press, heating soybeans is effective to increase oil production and to decrease energy consumption of the press. A proper temperature of soybean to extract the oil by the press was determined as about $50^{\circ}C$. 2. Soybean oil production and electric energy consumption of the press are about 83 ml and 58 Wh per 1 kg of soybeans heated to about $50^{\circ}C$, respectively. 3. The quality of crude oil produced by the press is similar to that of the commercially degummed and dried oil. The crude oil does not need to be degummed or dried for use as an engine fuel.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.14 no.1
• /
• pp.138-143
• /
• 2006

Modification of injector, oil ring tension reduction and oil pump rotor re-matching with optimization of relevant engine control parameters could drive fuel consumption reduction of HSDI diesel engine. A 5 holes injector was replaced with a 6 holes with smaller nozzle hole diameter and 1.5 k factor, and evaluated in a view of fuel economy and emission trade-offs. With introducing smaller nozzle hole diameter injector, PM(Particulate Matter) was drastically decreased for low engine load and low engine rpm. Modification of oil pump and oil ring was to reduce mechanical friction and be proved to better fuel economy. Optimization of engine operating conditions was a great help for the low fuel consumption. Influence of the engine operating parameters· including pilot quantity, pilot interval, air mass and main injection timing on fuel economy, smoke and NOx has been evaluated with 14 points extracted from NEDC(New European Driving Cycle) cycle. The fuel consumption was proved to $7\%$ improvement on an engine bench and $3.7\%$ with a vehicle.

• Applied Biological Chemistry
• /
• v.27
• /
• pp.80-87
• /
• 1984

Although traditional Korean diet consists of Very little fats and oils, the increase of their consumption, especially vegetable oil, has been truly remarkable in recent years and this increase is attributed to the improvement of their dietary habit and the development of Korean food industry. On the other hand, domestic production of the edible vegetable oil did not increase at all. Naturally, foreign exchange (over a several hundred million U.S. dollars) is annually used in importing oil seed and/or oil per se. Under these circumstances, it is of utmost importance to maximize the domestic production of edible vegetable oil, although its complete self-sufficiency cannot be achieved. In this seminar, intake of fats and oils by Korean people, status and outlook of the domestic production and consumption of fats and oils will be discussed, with. emphasis on the utilization of agricultural by products and waste as a source of fats and oil.

• Journal of Power System Engineering
• /
• v.19 no.3
• /
• pp.29-35
• /
• 2015

Environmental pollution is produced by consumption of fossil fuel, therefore alternative fuels is interested for development of new energy resources and reduction of exhaust emissions for air pollution prevention. Biofuels are produced from new vegetable oil and animal fat, may be used as fuel without change of engine structure in diesel engine. In this paper, the test results on specific fuel consumption, combustion characteristics of neat diesel oil and biodiesel blends(10 vol.% biodiesel and 20 vol.% biodiesel) were presented using four stroke, direct injection diesel engine, especially this biodiesel was produced from biodiesel fuel at our laboratory by ourselves. This study showed that specific fuel consumption is increased slightly, on the other hand cylinder pressure, rate of pressure rise, rate of heat release and soot were decreased slightly in the case of biodiesel blends than neat diesel oil.

• Journal of Advanced Marine Engineering and Technology
• /
• v.32 no.1
• /
• pp.27-32
• /
• 2008

Recently, we have a lot of interest in alternative fuels to provide energy independence from oil producing country and to reduce exhaust emissions for air pollution prevention. Biodiesel, which can be generated from natural renewable sources such as new or used vegetable oils or animal fats, may be used as fuel in diesel engine of compression ignition engine. In this paper, the test results on specific fuel consumption and exhaust emissions of neat diesel oil and biodiesel blends(10 vol.% biodiesel and 20 vol.% biodiesel) were presented using four stroke, direct injection diesel engine, especially this biodisel was produced from soybean oil at our laboratory. This study showed that Soot and CO emission were decreased as the blending ratios of biodiesel to diesel oil increased, on the other hand NOx emission was slightly increased because of the oxygen content in biodiesel. Also, the biodiesel blends yielded slightly higher specific fuel consumption than that of diesel oil because of lower heating value of biodiesel.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.8 no.5
• /
• pp.105-113
• /
• 2000

In order to clarify the final process of oil consumption, the distribution and flow of oil through each ring were visualized by induced fluorescence method. Motoring and firing test were performed in a single cylinder research engine with transparent cylinder liner. The appropriate calibration techniques were used to solve the unstability of induced light intensity as well as to know the relation of the oil film thickness and output signal. Oil behavior was also observed at dynamic state by high speed CCD camera. By analyzing the oil film thickness converted from the photographed image, it was observed that the main route of oil transport through each ring is the end gap under the usual operating condition, low engine speed and low load condition. Oil film thickness is observed to be irregular and tend to move in a body horizontally at a given piston land. And it is also found that oil flows through oil ring gap so quickly that it can be observed in a single cycle, but it flows so slowly through top and 2nd compression rings that it takes quite a long time to detect the flow.