• 설비공학논문집
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• 제21권9호
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• pp.496-504
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• 2009

In order to investigate the feasibility of a direct ice slurry transporting system for the purpose of district cooling, a case study of field application is performed. The research aims include the field measurement of ice packing factor, the performance of coldness delivery, and the branching characteristics of ice slurry. Two representative types of pipe branch are dealt with in this work. For the slurry flow with ice volume fraction of 0.16 or less, the pipe blocking due to aggregation is not observed. Based on the time-wise variation of temperature in the storage tank, a calculating method of ice packing factor is newly developed, which seems to be useful when the brine concentration is unknown. It is confirmed that the mass flow rate of ice slurry per unit cooling load is markedly reduced with increasing the ice content. The pumping power also decreases, but remains unchanged for high ice fractions. The distribution of ice particle before and after branching shows a good uniformity within the range of 5% difference, but yields a unique trend depending on the flow rate.

• 산업기술연구
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• 제21권B호
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• pp.141-147
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• 2001

For the preparation of calcium carbonate particles from aqueous $Ca(OH)_2$ slurry, carbonation reaction of aqueous $Ca(OH)_2$ slurry was carried out by batch method the $CO_2$ into reactor filled with aqueous slurry of $Ca(OH)_2$. The concentration of $Ca(OH)_2$ varies from 1.00 to 7.00wt%, reactor temperature at 20 and $40^{\circ}C$, and reactor pressure from atmospheric pressure to $6.0kg_f/cm^2$. Crystal structure of calcium carbonate was of calcite, the particle size were about $0.05{\sim}2.0{\mu}m$, and the particle shape was cubic and spindle. When reactor temperature was higher, particle size of calcium carbonate was bigger and particle shape was varied, but reaction rate was increased. When reactor pressure was higher, particle size of calcium carbonate was smaller, particle shape was cubic, and reaction rate was increased.

• Asian-Australasian Journal of Animal Sciences
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• 제23권9호
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• pp.1229-1235
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• 2010

With the increase of human activities since the Industrial Revolution, atmospheric greenhouse gas (GHG) concentration has increased, which is believed the cause of climate change. Methane ($CH_4$) fluxes were measured at two commercial swine barns (Jarvis and Guelph) with a four tower micrometeorological mass balance method. Two and three separate measurements were conducted at Jarvis and at Guelph, respectively. In the Jarvis experiments from May to July, mean $CH_4$ flux ($490.4{\mu}g/m^2/s$) during daytime was lower than that during nighttime ($678.0{\mu}g/m^2/s$) (p<0.05), which would be caused by break of slurry temperature stratification. In the Guelph experiment from January to April, mean $CH_4$ flux ($62.9{\mu}g/m^2/s$) during daytime was higher than that during nighttime ($39.0{\mu}g/m^2/s$) (p<0.05), which would be generated by high slurry temperature at 3 cm depth after April 6. Slurry temperature stratification in the Guelph experiment would happen from January to March.

• 한국세라믹학회지
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• 제45권12호
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• pp.777-781
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• 2008

Experiments were conducted using SUS430 and Crofer 22 APU steels coated by LSM using plasma spray and slurry spray methods, respectively. High-temperature conductivity and oxidation resistance were investigated. For comparison, SUS430 and Crofer 22 APU without LSM coating were also investigated and coefficient of thermal expansion (CTE) was measured. The results show that the materials without LSM coating exhibit almost the same CTE as YSZ electrolyte in a range of temperatures of $550{\sim}850^{\circ}C$. When coated with LSM, the oxidation rate of the steels decreases by $30{\sim}40%$ using slurry spray and by $10{\sim}30%$ using plasma spray whereas the steels using plasma spray have a better high-temperature conductivity than the steels using slurry spray. It is thus concluded that the LSM coating has a limited effect on increasing high-temperature conductivity while it can effectively reduce the oxidation of the steels.

• 대한기계학회논문집B
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• 제22권6호
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• pp.813-822
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• 1998

The microexplosion of a slurry droplet was considered to be caused by the shell formation and the following pressure build-up in the shell which would be promoted by the suppression of evaporation, subsequent superheating and heterogeneous nucleation of liquid carrier. To closely investigate the pressure build-up and the heterogeneous nucleation, a numerical model was introduced by considering the internal temperature distributions with the shell formation, suppression of evaporation and pressure build-up inside. The microexplosion time was estimated by postulating the limit of superheat for heterogeneous nucleation. The simulation yielded a reasonably good agreement with experimental results for Al/n-heptane slurry droplets under various solid loadings.

• 한국주조공학회지
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• 제10권4호
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• pp.309-315
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• 1990

Aluminum alloy matrix composites reinforced by SiC particles were prepared by rheocompocasting, a process which consists of the incoporation and distribution of reinforcement by stirring within a semi-solid alloy. When the volume fraction of SiCp and stirring speed were fixed, the dispersion of SiCp in Al-matrix alloy depended on stirring time and solid volume fraction in slurry. The results were as follows : 1) As a dispersed SiCp during stirring at $647^{\circ}C$ in 6063-Al alloy, SiC was better dispersed than that other temperature, where solid volume fraction was 43% in slurry. 2) When increased solid fraction in slurry, rate of dispersing SiC increased during stirring and porosities decreased in matrix alloy after casting. 3) Inspite of stirring with 800rpm, since solid particles of matrix alloy in slurry joined each other and occured joining growth, so that SiC was not dispersed into solid particle.

• Journal of Advanced Marine Engineering and Technology
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• 제30권3호
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• pp.376-381
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• 2006

This study is experimented to observe an influence of experimental conditions on production characteristics of slurry ice by putting ball into test section to disturb ice adhesion. And at this experiment it used ethylene glycol-water solution and the concentration is 20wt%. The experimental apparatus was constructed of ethylene glycol-water solution and slurry ice storage tank. brine tank, pumps for ethylene glycol-water solution and brine circulating, a mass flow-meter data logger for fluid temperature measuring and a vertical circular tube with two copper tubes as test section. The experiments were carried out under various conditions, with mean velocity of fluid at the entry ranging from 0.07 to 0.13m/s and ball diameter is 10mm, 15mm. Also ball filling rate is 33%, 50%.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2006년도 전기학술대회논문집
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• pp.49-50
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• 2006

This study experimented to observe an influence of experimental conditions on production characteristics of slurry ice by putting ball into test section to disturb ice adhesion. And at this experiment it used ethylene glycol-water solution and the concentration is 20wt%. The experimental apparatus was constructed of ethylene glycol-water solution and slurry ice storage tank, brine tank. pumps for ethylene glycol-water solution and brine circulating, a mass flow-meter, data logger for fluid temperature measuring and a vertical circular tube with two copper tubes as test section. The experiments were carried out under various conditions, with mean velocity of fluid at the entry ranging from 0.07 to 0.13m/s and ball diameter is 10mm, 15mm. Also ball filling rate is 33%, 50%.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2004년도 추계학술대회논문집
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• pp.99-102
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• 2004

In rheo forming process, slurry making is very important factor because the microstructure of slurry affects the quality of final products. To control the microstructure of slurry, slurry making by new rheo die casting was studied. In new rheocasting method, processes parameters are degree of overheat in molten metal, cooling condition, high frequency induction heating condition and cup temperature. Microstructures according to these parameters were observed. By image analysis, equivalent diameter and roundness of grain were investigated and discussed. To find out mechanical properties of grain controlled aluminum part by rheo die casting, tensile tests were carried out to the T6 heat treatment.

• 한국정밀공학회지
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• 제16권5호통권98호
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• pp.98-103
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• 1999

The application field of porous mold is more and more expended. A mixture of alumina and cast iron is used for making porous mold using slip and vacuum casting method in this study. Slip casting is a process that slurry is poured into silicon rubber mold, dried in vacuum oven, debinded and sintered in furnace, In this procedure, slurry is composed of powder, binder, dispersion agent, and water. Vacuum casting is a technique for removing air bubbles existed in the slurry under vacuum condition. Since ceramics has a tendency of over-shrinkage after sintering, cast iron is used to compensate dimensional change. The results shows that sintering temperature has a great effect on characteristics of alumina-cast iron composite sintered parts. Finally ceramic-metal composite sintered mold can be used for aluminum alloy casting of shoe mold using this process.