• Horticultural Science & Technology
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• v.29 no.3
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• pp.201-210
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• 2011

This experiment was conducted to investigate physical and chemical characteristics by volume fractions of root media using peatmoss, perlite, and vermiculite, along with effects on the growth of pot chrysanthemums (Dendranthema ${\times}$ grandiflorum 'Vemini') in a C-channel mat irrigation system. To evaluate the physico-chemical properties of 20 root media, the bulk density, particle density, total pore space, pore space, ash content, organic matter, pH, and electrical conductivity were measured and data were analyzed using principal component analysis (PCA). PCA scores revealed that physico-chemical properties changed by the blending of peatmoss, perlite, and vermiculite. The 20 root media were divided into three main groups by hierarchical cluster analysis. At the end of the experiment, the pH and EC of the root media were measured from media divided into four layers. The pH of root media without plants showed a strong linear relationship and the pH of root media with plants increased exponentially. The change of EC in the root medium was indicated as a hyperbolic curve. Plant growth characteristics according to growth in the 20 root media were analyzed by PCA. It was found that the mixing ratios of the root media affected plant growth characteristics. Therefore, mixing ratio is an important factor for pot-plant production in a subirrigation system.

• Applied Chemistry for Engineering
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• v.17 no.5
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• pp.490-497
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• 2006

$V_{2}O_{5}$/$TiO_{2}$ catalyst can be deactivated by ammonium salts formed by $SO_{2}$ oxidation and unreacted ammonium in presence of $SO_{2}$ in flue gas. The deactivation of catalyst by $SO_{2}$ depends on the $SO_{2}$ oxidation to $SO_{3}$. The oxidation of $SO_{2}$ is weakly affected by oxygen concentration, and strongly by the amount of vanadium loaded onto titania supports. Because unreacted ammonia is one of elements to form the ammonium salts, it is important to control the mole ratio of $NH_{3}/NOx$ in SCR. Thus the experiments about $NH_{3}/NOx$ were carried out. The reason of low activity of catalyst deactivated by ammonium salts is the change of pore volume. And TPD (Temperature Programmed Decomposition) was performed to find the decomposition of ammonium bisulfate on deactivated catalyst.

• Korean Journal of Food Science and Technology
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• v.19 no.6
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• pp.543-549
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• 1987

This study was carried out to estimate the change of Hg content in contaminated food materials including rice grain, soybean sprouts and crucian carp during their washing and cooking processes. The residue level of Hg in contaminated rice at 1 ppm level was decreased to the extent of 24% by three-times washing whereas it was not decreased in cooking. The removal efficiency of Hg in soybean sprouts contaminated at 80 ppm level was about 26% in three-times washing. While the Hg content was not decreased in blanching or cooking of soybean sprouts as a whole, the extent of leached Hg into the fluid part varied in the range of 23-41% depending on the heating time, salinity and volume of cooking water. While the Hg content in fish contaminated at 1 ppm level was not decreased in cooking as a whole, the leaching ratio of Hg into the fluid part was in the range of 2-10% depending on the salinity of cooking water. Disposal of inedible portion in cooked fish could remove 32% of contaminated Hg residue.

• Journal of the Korean Ceramic Society
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• v.41 no.7
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• pp.560-566
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• 2004

To fabricate the continuously porous alumina bodies by multi-extrusion process, carbon powder and ethylene vinyl acetate were used as a pore forming agent and a binder, respectively. As the change of extrusion pass number, reduction ratio as well as the volume fraction of core and tube, the porous alumina bodies having various kind of pore size and porosity could be obtained. The porous bodies showed continuous pore shape, high specific surface as well as high bending strength, which were compared with those of commercial alumina bodies. In-vitro study was carried out using MG-63 osteoblast cells to investigate of their biocompatibility. As a result, the cells grew well on top and bottom as well as inside surface of pore. From the result of in-vivo study of 3-dimensional porous alumina bodies using rats, it was confirmed that any inflammatory response was not found in the subcutaneous tissue around porous body. Also the porous bodies removed from the rats were fully covered with well-developed fibrous tissues and showed the formation of new capillary blood vessels.

• Computers and Concrete
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• v.26 no.1
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• pp.75-94
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• 2020

The aim of this research is to investigate free vibration of a novel five layer Timoshenko microbeam which consists of a transversely flexible porous core made of Al-foam, two graphen platelets (GPL) nanocomposite reinforced layers to enhance the mechanical behavior of the structure as well as two piezo-magneto-electric face sheets layers. This microbeam is subjected to a thermal load and resting on Pasternak's foundation. To accomplish the analysis, constitutive equations of each layer are derived by means of nonlocal strain gradient theory (NSGT) to capture size dependent effects. Then, the Hamilton's principle is employed to obtain the equations of motion for five layer Timoshenko microbeam. They are subsequently solved analytically by applying Navier's method so that discretized governing equations are determined in form of dynamic matrix giving the possibility to gain the natural frequencies of the Timoshenko microbeam. Eventually, after a validation study, the numerical results are presented to study and discuss the influences of various parameters such as nonlocal parameter, strain gradient parameter, aspect ratio, porosity, various volume fraction and distributions of graphene platelets, temperature change and elastic foundation coefficients on natural frequencies of the sandwich microbeam.

• Transactions of the Korean hydrogen and new energy society
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• v.27 no.6
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• pp.712-720
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• 2016

When bioethanol and water are mixed at a proper ratio, phase separation can occur because of the immiscibility of biobutanol with water. Phase separation in bioethanol blends fuels is a major problem for gasoline vehicle users due to effect of octane number and component corrosion. Thus, in this study, the phase separation of bioethanol was examined effect of bioethanol blends (E3 (3 vo.% bioethanol in gasoline), E5 and E10) in presence of water. The effect were evaluated behavior with phase separation test, simulation test of fuel tank in gas station according to water addition volume and it was investigated change of water content, bioethanol content and octane number for gasoline phase in bioethanol blends (E3, E5 and E10) every 1 week after water addition. The E3 occurred phase separation more easily than the E5 and E10 in small water contents because solubility of water on ethanol content difference in gasoline-ethanol. It was kept a initial level of water content, bioethanol content, and octane number by repeated sample replacing in simulation test of fuel tank.

• Journal of the Korean Institute of Gas
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• v.11 no.4
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• pp.17-22
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• 2007

The NOx emission characteristics with oxygen enrichment in non-premixed counterflow flames were investigated numerically. To consider systematically the situation of inevitable $N_2$ contamination by air infiltration in the process of pure-oxygen combustion, the volume ratio of $O_2$ in an oxidizer was changed from 21% to 100%. As a result the NO emission index $(EI_{NO})$ has the highest value under condition of 75% oxygen enrichment. This result can be explained by the change of $N_2$ destruction rate with oxygen enrichment rather than flame temperature, flame thickness and residence time. In particular, it was found that the reaction of N+NO=$N_2+O$ has the largest contribution on NOx production in oxygen-enrichment flames.

• Korean Institute of Interior Design Journal
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• v.19 no.1
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• pp.180-189
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• 2010

Since collective houses are started to be supplied, the housing market has been transformed from supplier to demander oriented, and various type with same area of unit households have been deigned and started to be distributed. It can be expected that such transfer phenomenon would be continuously sped-up, and unit household will be more subdivided and varied. Thus, we analysed and studied the planes with subject of unit households in national housing scale ($85m^2$) that is treated as supply standard and has biggest volume in construction by Korean housing corporation. The analysing method is investigating the area of each room within unit household, calculating their minimum, maximum, and average values, studying the efficiency of unit household plane according to the structure of each room by comparative analysis these values, and analysing changing matter by investigating any change of each room area. The analysing results of which are followings. At first, number of BAY on face is increasing. Second, allocation of each room has been vary. Third, area ratio among bedroom1, livingroom, diningroom/kitchen become similar. Fourth, the area of diningroom/kitchen become somewhat bigger. Fifth, the space for passage way is efficiently allocated. Sixth, service area is reduced, Seventh, stereotyped phenomenon Is appeared. Based on many studies so far, any improvements of unit householder in national housing scale are followings. First, in terms of forming style, unit householder in national housing scale is unfolded in various way though, the form of each room is not more than typical style. Second, it shows stereotyped phenomenon. Especially, bathroom 1, 2 show stereotyped feature in terms of their type and area across entire research years, also LDK allocation method is stereotyped, as well as stereotyped trend in bedroom 2, 3, allocation for 4 BAY type.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.5
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• pp.2610-2616
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• 2014

An ejector is a kind of pump which is using pressure energy of high pressure fluid. This study aims to investigate performance influencing according to change the ejector mixing section shape using CFD simulation by Finite Volume Method. Optimum conditions were suggested 3 kind of variable such as nozzle diameter, nozzle length, distance from nozzle tip to the diffuser inlet. The results, It was confirmed that the diameter of the nozzle was the greatest effect in performance of the ejector. The diameter of the nozzle get smaller, mixing ratio was increased. On the other hand, nozzle length, distance from nozzle tip to the diffuser inlet had little effect on performance. It was proposed specific Mixing section, Nozzel diameter 23.8mm using the Artificial Neural Network.

• Journal of the Korean Geotechnical Society
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• v.33 no.11
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• pp.45-57
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• 2017

Temperature change affects consolidation behavior of soft clays. The increase of temperature in soft clays induces the increase of pore water pressure. The dissipation of the excess pore water pressure decreases volume and void ratio. Also, the consolidation rate is accelerated by high temperature which induces the decrease of viscosity of pore fluid. The effects of temperature on the consolidation behavior such as consolidation settlement, consolidation time, and pore water pressure were investigated in this study. A numerical analysis of hydro-mechanical (HM) and thermo-hydro-mechanical (THM) behavior was performed. The combination of heat injection and sand drain for consolidating the soft ground, with varying temperature (40 and $60^{\circ}C$) and sand drain diameter (40, 60, and 80 mm), was considered. The results show that the temperature inside soil specimen increases with the increase of the temperature of heating source and the diameter of sand drain. Moreover, the heat injection increases the excess pore water pressure and, accordingly, induces additional settlement in overconsolidated (OC) state and reduces the consolidation time in normally consolidated (NC) state.