• Current Research on Agriculture and Life Sciences
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• v.27
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• pp.29-33
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• 2009

Liquefied-wood polymer composite was prepared and mechanical properties was evaluated to develop potential utility of liquefied wood. The liquefied wood was made from waste wood and chemical modified with acetic anhydride and maleic anhydride (MA), phtalic anhydride (PA). The composite sheet was prepared from modified liquefied-wood and polymer(PE). The mechanical, chemical and microscopical properties composite sheet were investigated. The results were summarized as follows, 1. The tensile strength was increased and breaking elongation of composite sheet was decreased with the time of acetylation and the dosage of MA. 2. The Young's modulus of composite sheet was gradually decreased with the dosage of PA. 3. The peak intensity of 1737cm-1 in FT-IR spectra of chemical modified liquefied woods was increased. 4. The dispersity of liquefied woods with PE was improved with chemical modification.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.2
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• pp.158-165
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• 2008

The combustion and exhaust emissions characteristics of a liquefied petroleum gas-di-methyl ether compression ignition engine with a variable valve timing device were investigated under various liquefied petroleum gas injection timing conditions. Liquefied petroleum gas was used as the main fuel and was injected directly into the combustion chamber. Di-methyl ether was used as an ignition promoter and was injected into the intake port. Different liquefied petroleum gas injection timings were tested to verify the effects of the mixture homogeneity on the combustion and exhaust emission characteristics of the liquefied petroleum gas-di-methyl ether compression ignition engine. The average charge temperature was calculated to analyze the emission formation. The ringing intensity was used for analysis of knock characteristics. The combustion and exhaust emission characteristics differed significantly depending on the liquefied petroleum gas injection and intake valve open timings. The CO emission increased as the intake valve open and liquefied petroleum gas injection timings were retarded. However, the particulate matter emission decreased and the nitrogen oxide emission increased as the intake valve open timing was retarded in the diffusion combustion regime. Finally, the combustion efficiency decreased as the intake valve open and liquefied petroleum gas injection timings were retarded.

• Journal of the Korean Wood Science and Technology
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• v.23 no.2
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• pp.19-25
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• 1995

This research was carried out to investigate the methods of liquefaction with Pinus koraiensis, and chemical components of the liquefied wood by FT-IR analysis and pyrolysis-GC/MS. Acetylated wood powder was liquefied above 90% in phenol or m-cresol when treated at about 150$^{\circ}C$ for 30min., using some catalysts. Untreated wood powder was liquefied above 90% in phenol or m-cresol when treated at about 200$^{\circ}C$ for 60min., using some catalysts. The results of FTIR analysis, carbohydrates were terribly disintegrated, the other side lignin peaks were occurred in liquefied wood, particulary. The results of pyrolysis-GC/MS, the liquefied wood have clear four peaks, phenol, guaiacol, o-cresol and m-/p-cresol, due to degradation of lignin, particulary.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.11a
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• pp.23-24
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• 2019

In this paper, the compressive strength characteristics of cement paste were compared with the addition of liquefied red mud with the addition of nitric acid in order to improve the strength of the deteriorated cement. The results showed that the compressive strength with between 7 days and 28 days was greater than that of liquefied red mud. The ratio of daily compressive strength of the liquefied red mud is higher than that of the Plain with a 1 percent addition rate, and the ratio of compressive strength is lower than that of the Plain on the 28 days. Therefore, the compressive strength of neutralization liquefied red mud compared to liquidated red mud was relatively high, and the compressive strength of the red mud was shown to be improved to a level almost similar to that of Plain.

• Journal of Korean Society on Water Environment
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• v.37 no.4
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• pp.306-314
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• 2021

The application of organic fertilizer could be accompanied by potential hazards to soil and humans due to trace metals. Livestock manure compost·liquefied fertilizer is a well-established approach for the stabilization of nutrients and the reduction of pathogens and odors in manures, which can be evaluated as compost·liquefied. In this study, the livestock manure compost·liquefied fertilizers produced at 333 liquid manure public resource centers and liquid fertilizer distribution centers were collected from May to December 2019. The nutrient content (nitrogen, phosphorus, and potassium), physicochemical properties, and heavy metal content were investigated. The livestock manure compost·liquefied fertilizer was measured using a mechanical maturity measurement device. The organic matter, arsenic, cadmium, mercury, lead, chromium, copper, nickel, zinc, E. coli (O157:H7), Salmonella, etc. of the livestock manure compost·liquefied fertilizers were analyzed. The average heavy metal content in the livestock manure compost·liquefied fertilizer was as follows: Cr 2.9 mg/kg (0.2~8.7 mg/kg), Cu 20.4 mg/kg (1.6~74.1 mg/kg), Ni 1.3 mg/kg (0.4~4.2 mg/kg), and Zn 79.8 mg/kg (3.0~340.7 mg/kg). Although large-scale organic fertilizer plants and resources recycling centers produce good organic (liquid) fertilizers with proper components, it is necessary to standardize livestock manure compost·liquefied fertilizer in order to facilitate efforts to turn livestock manure into useful resources.

• Korean Journal of Environmental Agriculture
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• v.42 no.4
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• pp.418-426
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• 2023

This study focused on nitrous oxide, a major greenhouse gas produced in agricultural settings through bacterial nitrogen oxidation in aerobic soil. Nitrogen fertilizer in farmland is identified as a primary source of nitrous oxide. The importance of reducing excess nitrogen in soil to mitigate nitrous oxide production is well-known. The study investigated the use of liquefied pig manure as an alternative to urea fertilizer in conventional agriculture. Results showed a more than two-fold reduction in nitrous oxide emissions in pepper cultivation areas with liquefied pig manure compared to that with urea fertilizer. The population of Nitrosospira, a nitrous oxide-producing bacterium, decreased by over 10% with liquefied pig manure. Additionally, nirK and nosZ, which are related to the denitrification process, significantly increased in the urea fertilizer group, whereas levels in the liquefied pig manure group resembled those with no nitrogen treatment. In conclusion, the experiment confirmed that liquefied pig manure can serve as an eco-friendly nitrogen fertilizer, significantly reducing nitrous oxide production, a major contributor to the atmospheric greenhouse effect.

• Journal of Korea Foresty Energy
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• v.21 no.3
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• pp.18-27
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• 2002

Pine bark was liquefied in the presence of phenol using organic sulfonic acids as catalysts, and the liquefied barks were characterized. It was found that the organic sulfonic acids were more effective catalysts than hydrochloric acid for complete liquefaction of pine bark. The liquefied barks prepared from phenol-organic sulfonic acid liquefaction were highly phenolated, and the amounts of combined phenol were 2-3 times greater than that of the liquefied bark obtained from phenol-hydrochloric acid liquefaction. The glass transition points (Tg) were lower than that of the liquefied barks prepared from phenol-hydrochloric acid. It can be concluded that by using the organic sulfonic acids, the phenol used as a liquefying reagent is highly introduced into the bark, resulting in the phenolated bark preventing further condensation reactions, which may occur during the liquefaction. The carbohydrates such as cellulose and hemicellulose in the liquefied barks were almost decomposed during the liquefaction, from the results of IR spectra and neutral sugar analyses. Energy dispersive X-ray spectromery (EDS) results from the residues and the liquefied barks showed that the organic sulfonic acid catalysts did not lead to serious corrosion of the reactor compared with the hydrochloric acid catalyst.

• Journal of Power System Engineering
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• v.11 no.1
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• pp.56-62
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• 2007

This paper represents the cold energy for liquefied nitrogen gas and cascade refrigerator. In this study, the vaporizer of liquefied nitrogen gas has the fin coil tube type with the dimension of inside diameter of 10mm and outside diameter of 12mm. Also, the total length of vaporizer is 20,000mm. The main experimental parameters are the mean velocity in duct and the supplied flow-rates of liquefied nitrogen gas. For the cascade refrigeration system, the refrigerants are ethane(R 170) in the high pressure stage and R 22 in the low pressure stage.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.12 no.2
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• pp.131-139
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• 2000

A direct hydrogen liquefaction equipment has been developed and tested, which consists of a GM refrigerator, a liquefaction vessel, a radiation shield, a cryostat, and an ortho-para converter with catalyst. The effect of ortho-para hydrogen conversion on the performance of hydrogen liquefaction has been investigated. The time needed for the hydrogen liquefaction process with hydrogen pressure charge of 4 atm was delayed to around 75 minutes, and the liquefied mass flow rate of the hydrogen was about 0.0150∼ 0.0205 g/s when the hydrogen was liquefied with the direct hydrogen liquefaction system considering ortho-para conversion. With ortho-para conversion, the liquefied mass flow rate decreased up to 20%. Considering ortho-para conversion, there were up to 30% increase in the work input per unit liquefied mass flow rate. When the ortho-para conversion was considered, FOM decreased to be about 0.031∼0.045.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.03a
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• pp.148-154
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• 2004

As a rocket propellent of hydrocarbon fuels, the characteristics of liquefied natural gas was evaluated with the viewpoint of the constituents and content, the cooling performance as a coolant, and characteristic velocity and specific impulse as parameters of the engine performance. Content of methane was a principal factor to determine the characteristics as a rocket propellant and more than 90 % of it was needed as a fuel and coolant in the regenerative cooled liquid rocket engine. Some constituents of the liquefied natural gas can be frozen by the pre-cooling of the pipe lines, therefore they can be a factor disturbing the normal working of engine. In case the content of methane is around 90% in the liquefied natural gas, a normalized stoichiometric O/F mixture ratio of 0.75 is suggested for a nominal operation condition to get the maximum specific impulse and characteristic velocity.