• Journal of Life Science
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• v.24 no.1
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• pp.39-45
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• 2014

Salmonella typhimurium MMP13 and S. typhimurium ${\chi}8554$ were derived from weak JOL401 and strong ${\chi}3339$ virulent strains. Heat-labile subunit B (LT-B) was used as an adjuvant to increase the effectiveness of the vaccine. Plasmid pMMP184 carrying a ghost cassette was transformed into MMP13 and ${\chi}8554$ to produce the ghost, and the prepared ghost cells were administered into the muscles of BALB/c mice. In the absence of the adjuvant, the total IgG content showed a tendency to increase contrary to the original virulent strength. In contrast, in the presence of the adjuvant, the strain that originated from the strong virulent showed a tendency to promote the immune more than that of weak virulent strain. However, the final concentration of total IgG was similar between the compared groups, indicating that the originated virulent strength does not affect a specific immune. Other elements of the immunoglobulins IgG1, IgG2a, and sIgAs did not show a specific trend. The results of Salmonella challenge showed a similar tendency to regardless of the originated virulence. Taken together, the results suggest that the Salmonella ghost cells promoted the immune system of BALB/c mice, irrespective of the virulence applied to create the ghost cells.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.26 no.1
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• pp.47-59
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• 2023

Due to climate change and urbanization, abnormally high temperatures and heat waves are expected to increase in urban and deteriorate thermal comfort. Planting of street trees and changing the albedo of urban surfaces are the strategies for mitigating the thermal environment of urban, and both of these strategies affect the exposure and blocking of radiative fluxes to pedestrians. After measuring the shortwave and longwave radiation according to the ground surface with different albedo and the presence of street trees using the CNR4 net radiometer, this study analyzed the relationship between this two strategies in terms of thermal environment mitigation by calculating the MRT(Mean Radiant Temperature) of each environment. As a result of comparing the difference between the downward shortwave radiation measured under the right tree and at the control, the shortwave radiation blocking effect of the tree increased as the downward shortwave radiation increased. During daytime hours (from 11 am to 3 pm), the MRT difference caused by the albedo difference(The albedo of the surfaces are 0.479 and 0.131, respectively.) on surfaces with no tree is approximately 3.58℃. When tree is present, the MRT difference caused by the albedo difference is approximately 0.49℃. In addition, in the case of the light-colored ground surface with high albedo, the surface temperature was low and the range of temperature change was lower than the surrounding surface with low albedo. This result shows that the urban thermal environment can be midigate through the planting of street trees, and that the ground surface with high albedo can be considered for short pedestrians. These results can be utilized in planning street and open space in urban by choosing surfaces with high albedo along with the shading effect of vegetation, considering the use by various users.

• Korean Journal of Materials Research
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• v.33 no.1
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• pp.15-20
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• 2023

'Tracers' are bullets that emit light at the backside so that the shooter can see the trajectory of their flight. These light-emitting bullets allow snipers to hit targets faster and more accurately. Conventional tracers are all combustion type which use the heat generated upon ignition. However, the conventional tracer has a fire risk at the impact site due to the residual flame and has a by-product that can contaminate the inside of the gun and lead to firearm failure. To resolve these problems, it is necessary to develop non-combustion-type tracers that can convert heat to luminance, so-called 'thermoluminescence (TL)'. Here, we highly improve the thermoluminescence properties of MgB₄O₇ through co-doping of Dy³⁺+Ce³⁺ and Dy³⁺+Na⁺. The presence of doping materials (Dy³⁺, Ce³⁺, Na⁺) was confirmed by XPS (X-ray photoelectron spectroscopy). The as-synthesized co-doped MgB₄O₇ was irradiated with a specific radiation dose and heated to 500 ℃under dark conditions. Different thermoluminescence characteristics were exhibited depending on the type or amounts of doping elements, and the highest luminance of 370 cd/m² was obtained when Dy 10 % and Na 5 % were co-doped.

• Clean Technology
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• v.20 no.4
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• pp.383-389
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• 2014

$CO_2$ absorption processes have a good potential for large scale capture of $CO_2$ but a large amount of absorbing solution has to be regenerated, undesirably increasing the consumption of energy such as sensible heat and latent heat of vaporization. In this study, a cooling crystallization process which would separate the $CO_2$-rich potassium bicarbonate crystals from $CO_2$-lean water was developed to reduce the energy penalty. Sterically hindered alkanolamine additives were used to enhance the $CO_2$ removal efficiency and their antisolvent effect on the crystallization was found in a continuous cooling crystallizer. The production yields of crystals were increased in the sequence of 2-amino-2-methyl-1-propanol (AMP) < 2-amino-2-methyl-1,3-propanediol (AMPD) < 2-amino-2-hydroxymethyl-1,3-propanediol (AHPD), which are related to the number of hydroxyl groups in the additive molecules. Using $^{13}carbon$ nuclear magnetic resonance, the additives favored the formation of bicarbonate ions by steric hindrance effect and increased the supersaturation of $KHCO_3$. It is shown that the additives increase the mean size of crystals and crystal growth rate by increasing supersaturation. The additives are promising for enhancing the $CO_2$ removal efficiency and reducing the regeneration energy cost of $CO_2$ absorbing solution by promoting $KHCO_3$ crystallization.

• Clean Technology
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• v.29 no.3
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• pp.185-192
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• 2023

This study was conducted to obtain basic process simulation data before conducting pyrolysis experiments for the development of a thermochemical conversion system by recirculation of heat carrier and gases thereby. In this study, polypropylene (PP) was used as a pyrolysis sample material as an alternative to waste plastics, and fluid sand was used as a heat transfer medium in the system. Manganese (Mn) was chosen as the catalyst for the pyrolysis experiment, and the catalyst pyrolysis was performed by impregnating it in the sand. The basic properties of PP were analyzed using a thermogravimetric analyzer (TGA), and liquid oil was generated through catalytic pyrolysis under a nitrogen atmosphere at 600℃. The carbon number distribution of the generated liquid oil was confirmed by GC/MS analysis. In this study, the effects of the presence and the amount of Mn loading on the yield of liquid oil and the distribution of hydrocarbons in the oil were investigated. When Mn/sand was used, the residue decreased and the oil yield increased compared to pyrolysis using sand alone. In addition, as the Mn loading increased, the ratio of C₆~C₉ range gasoline in the liquid oil gradually increased, and the distribution of diesel and heavy oil with more carbon atoms than C₁₀ in the oil decreased. In conclusion, it was found that using Mn as a catalyst and changing the amount of Mn could increase the yield of liquid oil and increase the gasoline ratio in the product.

• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.5
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• pp.816-828
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• 1995

During the industrial preparation and the storage of foods, the side chain of some protein-bound amino acids can react chemically each other or with other molecules present in the food. The following reactions have been described : destruction of amino acids, racemization, protein-protein interactions, reactions of proteins with reducing sugars, oxidizing agents, or polyphenols. Apart from total destruction, the main reacitons are the forming of Maillard reactions products(e.g. fructoselysine) and the crosslinking with other amino acids in the same or in another protein molecule(e.g. lysinoalanine). The most often involved amino acid is lysine because of its free functional ${\varepsilon}-amino$ acid group. Generally derivatives of amino acids or crosslinks in polypeptides influence the bioavailability and the overall digestibility of the protein. This work reviews the technological, analytical, nutritional, and physiological problems related to the formation of fructoselysine and lysinolalnine in human foods, and evaluates the possible health risk for humans. A summary of the available information is of help in considering whether or not the presence of fructoselysine/lysinoalanine in foods represents a danger to man. The reduction in protein quality through these reactions is not a problem for the general population, but it is extremely important in infant foods, since infants are often nourished with a limited number of food product(e.g. formular foods) which are sensitive to the Mailard reaction.

• Resources Recycling
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• v.30 no.1
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• pp.53-59
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• 2021

Waste vinyl generated from household waste has been used as a solid refuse fuel (SRF) due to the presence of impurities such as soil, metal, and glass; however, the amount of SRF used has been decreasing owing to recent environmental problems, thereby necessitating the need for recycling. In this study, the mixed recycled raw material produced from household waste vinyl and polyethylene (PE) single recycled raw material produced from agricultural waste vinyl were examined. Raw material analysis revealed that waste vinyl was mainly composed of polyethylene, and approximately 2% of ash remained in the mixed recycled raw material, whereas no ash was found in the PE single recycled raw material. In addition, the analysis of tensile strength according to the mixing ratio of the two recycled raw materials revealed that the highest tensile strength was approximately 16 MPa under the heat treatment temperature of 200 ℃, compression pressure of 30 MPa, and a mixing ratio of 3:7 (mixed:PE single). In addition, the highest bending strength was approximately 39 MPa under the heat treatment temperature of 200 ℃, compression pressure of 30 MPa, and a mixing ratio of 3:7 (mixed:PE single). Therefore, the possibility of recycling waste vinyl was suggested by investigating the change in strength characteristics according to the mixing ratio of the recycled raw materials.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.4
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• pp.405-412
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• 2012

In the MCFC power generation system, the combustor supplies a high temperature mixture of gases to the cathode and heat to the reformer by using the off-gas from the anode; the off-gas includes high concentrations of $H_2O$ and $CO_2$. Since a combustor needs to be operated in a very lean condition and avoid local heating, a catalytic combustor is usually adopted. Catalytic combustion is also generally accepted as one of the environmentally preferred alternatives for generation of heat and power from fossil fuels because of its complete combustion and low emissions of pollutants such as CO, UHC, and $NO_x$. In this study, experiments were conducted on catalytic combustion behavior in the presence of Pd-based catalysts for the BOP (Balance Of Plant) of 5 kW MCFC (Molten Carbonate Fuel Cell) power generation systems. Extensive investigations were carried out on the catalyst performance with the gaseous $CH_4$ fuel by changing such various parameters as $H_2$ addition, inlet temperature, excess air ratio, space velocity, catalyst type, and start-up schedule of the pilot system adopted in the BOP.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.5
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• pp.716-722
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• 2017

The present study numerically investigates the effect of obstacles located in the trajectory of fire plume flow on heat flow characteristics by using Fire Dynamics Simulation (FDS) software in an underground combined cycle power plant (CCPP). Fire size is taken as 10 MW and two different locations of fire source are selected depending on the presence of an obstacle. As the results, when the obstacle is in the trajectory of fire plume, hot plume arrives at the ceiling about 5 times slower in the upper of the fire in comparison to the results without obstacle. In addition, the average propagation time of ceiling jet increases by about 70 % with the distance from the ceiling in the upper of the fire, and it increases mainly about 4 times at the distance of 10 m. Consequently, it is noted that the analysis of heat flow characteristics in the underground CCPP considering fire scenarios is essential to develop the fire detection system for initial response on evacuation and disaster management.

• Journal of the Korean Electrochemical Society
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• v.2 no.4
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• pp.221-226
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• 1999

Two needle cokes (NC-A and NC-B) that differ in both the texture and impurity content to each other were graphitized at $2000-3000{\circ}C$, and the average particle size, size distribution and surface area were compared after milling. Their anodic properties in Li secondary batteries were also analyzed. Two materials showed a higher degree of graphitization with an increase in the preparation temperature, however, the NC-B series was less graphitized than NC-A due to the presence of impurities and less ordered mosaic texture. The mein particle size of the milled powder was proportional to the degree of graphitization, but the surface area showed the opposite trend. The highly graphitized materials yielded powders of lower uniformity in the size distribution. The discharge capacity of the resulting carbons steadily decreased in the temperature range of 1000 to $2000^{\circ}C$ due to the depletion of carbonaceous interlayers that contain crystal defects. A later increase in the discharge capacity was observed at $>2000^{\circ}C$, which arises from the formation of graphitic interlayers. The milling process gave rise to a sloping discharge curve at >1.0 V, but this was converted to a plateau at <0.25V after a repeated cycling or additional heat-treatment at $1000^{\circ}C$. The discharge at >1.0V likely comes from the disordered surface structure formed during the milling process. The evolution of a plateau at <0.25 V suggests that this disordered structure transforms to a more ordered graphitic one upon a cell cycling or heat-treatment.