• Journal of Energy Engineering
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• v.11 no.2
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• pp.114-121
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• 2002

Alkali metal compounds existed in original coal or sorbents are exhausted as vapor or small particle at the outlet of combustor when operating PFBC power plant. These compounds can be removed with dust removal equipment, but total generation efficiency will be decreased because of lower operating temperature of dust removal equipment. Alkali metal contained in vapor phase is initially deposited onto turbine blade results in serious corrosion. The concentration of alkali vapor in the PFBC flue gas is 20∼40 ppm which is dependent on mineral characteristics and composition as well as operating condition of PFBC. However, the allowance limit of alkali metal vapor is assigned as less than 50 ppb for gas turbine when coal or oil is used as fuel. Therefore, alkali metal vapor in PFBC or IGCC process should be removed by solid sorbents to prevent corrosion of turbine blade and improve plant efficiency. In the present investigation, powder of Bauxite, Kaolinite and Limestone is used in the preparation of cylinder-type pellet which is inserted into the pressurized alkali removal reactor for the alkali absorption experiment. Experimental results showed that the alkali removal efficiency in the order of Bauxite, Kaolinite and Limestone. Alkali vapor removal efficiency is related with reaction temperature, porosity of pellet and alkali vapor concentration of flue gas.

• The Journal of Engineering Geology
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• v.23 no.4
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• pp.447-455
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• 2013

A micro-mechanical pipe network model with the shape of a cube was developed to simulate the behavior of fluid flow through a porous medium. The fluid-flow mechanism through the cubic pipe network channels was defined mainly by introducing a well-known percolation theory (Stauffer and Aharony, 1994). A non-uniform flow generally appeared because all of the pipe diameters were allocated individually in a stochastic manner based on a given pore-size distribution curve and porosity. Fluid was supplied to one surface of the pipe network under a certain driving pressure head and allowed to percolate through the pipe networks. A percolation condition defined by capillary pressure with respect to each pipe diameter was applied first to all of the network pipes. That is, depending on pipe diameter, the fluid may or may not penetrate a specific pipe. Once pore pressures had reached equilibrium and steady-state flow had been attained throughout the network system, Darcy's law was used to compute the resultant permeability. This study investigated the sensitivity of network size to permeability calculations in order to find out the optimum network size which would be used for all the network modelling in this study. Mean pore size and pore size distribution curve obtained from field are used to define each of pipe sizes as being representative of actual oil sites. The calculated and measured permeabilities are in good agreement.

• Tunnel and Underground Space
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• v.16 no.1 s.60
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• pp.50-57
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• 2006

Development of structures such as slope and tunnel, waste disposal, oil and LPG storages, and underground power house and so on, is increasing with the year. The method for appropriate estimation of rock state such as fresh or damaged rocks is also requested with increasing structural development. On these purposes, seismic logging system, which is a simple and easy way for handling as well as small and light, has been developed. Seismic logging method is one of logging tests, which is able to evaluate the state of rock mass with various shapes and is possible to obtain the relatively accuracy data at situ state. In addition, seismic logging method is at to apply to estimate structural behavior, before and after support installed. According to the results obtained from this study, firstly, it is clear that the extent of damage in rock slope due to blasting is able to be evaluated with quantity using seismic logging method, moreover to decide the damage zone in rock slope reasonably. Secondly, it is expected that installing depth of support is able to be decided more effectively and economically, using the results of seismic logging data. Finally, seismic logging method is also able to be applied safety supervision of structures, before and after support installed.

• Journal of the Korean Dietetic Association
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• v.6 no.2
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• pp.125-135
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• 2000

Hypertension is a well-known degenerative disease whose prevalence rate increases with age. Management of high blood pressure is a critical concern in preventive strategies to reduce the morbidity and mortality for cardiovascular disease. The purpose of this study was to examine the dietary characteristics of hypertensive program participants, and to establish strategies based on their nutritional needs. Hypertensive patients were enrolled in the program in a public health center or in a local elderly center, at Suwon, in 1999-2000. Trained dietitians interviewed 62 enrollees(24-hour recall) and related variables. Mean body mass index of the subjects was 25.0kg/m². 30.7% of the subjects had a family history of hypertension. The majority of them ate regularly and partook of all available side dishes. They consumed grains and vegetables regularly, but seldom ate dairy products or food prepared with oil. Male enrollees frequently consumed more processed food and animal fat than did female enrollees(p<0.05). An analysis of the percentage of RDA(Recommended Dietary Allowances of Korea 1995) showed that but for ascorbic acid, enrollees consumed nutrients below the RDA. The food group intake pattern was not diverse, thus only 8.1% of enrollees consumed all food groups in a day. An analysis of eating attitude showed that 64.5% of enrollees always added salt to beef soup. Male enrollees showed low food-related self-efficacy compared to female enrollees, especially with reference to reduction of instant food intake(p<0.01), increase in vegetable intake(p<0.01), reduction of monosodium glutamate(MSG) intake(p<0.01). and not overeating(p<0.05). Their perceived barriers for participating in hypertension nutrition programs included lack of time, program necessity non-recognition, and program comprehension difficulty. These results suggest that nutrition education program necessity non-recognition, and program comprehension difficulty. These results suggest that nutrition education programs for community hypertensive patients should focus on increasing participant consumption of foods, expecially dairy products, and desirable eating attitudes. It also suggests that the program should consider should consider encouraging self-efficacy in changing eating behavior.

• Applied Chemistry for Engineering
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• v.29 no.2
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• pp.215-224
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• 2018

Influences of the magnetic field on 5, 10 and 15 wt% (1.5, 3 and 4.5 M) HCl solution behaviour, which has widespread applications in petroleum well acidizing, were investigated in various conditions. Differences in the pH of magnetized hydrochloric acid compared to that of normal hydrochloric acid were measured. Taguchi design of experimental (DoE) method were used to model effects of the magnetic field intensity, concentration, velocity and temperature of acid in addition to the elapsed time. The experimental results showed that the magnetic field decreases [$H^+$] concentration of hydrochloric acid up to 42% after magnetization. Increasing the magnetic field intensity (with 28% contribution), concentration (with 42% contribution), and velocity of acid increases the effect of magnetic treatment. The results also demonstrated that the acid magnetization was-not influenced by the fluid velocity and heating. It was also displayed that the acid preserves its magnetic memory during time. The optimum combination of factors with respect to the highest change of [$H^+$] concentration was obtained as an acid concentration of 10% and an applied magnetic field of 4,300 Gauss. Due to the reduction of HCl reaction rate under the magnetization process, it can be proposed that the magnetized HCl is a cost effective and reliable alternative retarder in the matrix acidizing of hydrocarbon (crude oil and natural gas) wells.

• Asian-Australasian Journal of Animal Sciences
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• v.33 no.1
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• pp.111-119
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• 2020

Objective: This study was conducted to examine the effects of a mixture of pinecone oil, garlic, and brown seaweed extracts (PGBE) on milk production traits as well as physiological and ethological parameters in Holstein cows during the summer season (24 May to 03 July 2015, Korea). Methods: Among the extract combinations tested, we found that the level of 2,2'-azino-bis (3-ethylberzothiazoline-6-sulphonic acid) cation radical scavenging activity of the 0.16% PBGE complex at ratio of 1:1:1 (vol/vol) was comparable to that of the control (ascorbic acid; 1 mg/mL). Additionally, the PBGE complex reduced lipopolysaccharide-induced COX-2 expression in bovine mammary epithelial cells. Based on these findings, 40 lactating Holstein cows were used to measure the effects of PBGE complex at ratio of 1:1:1 (vol/vol) on milk production, immune response, metabolites, and behavior patterns by dividing the cows into two groups fed diets containing PGBE complex (n = 20; 0.016%/kg feed dry matter basis) or not containing PGBE complex (control, n = 20) for 40 d. Results: Results showed that PGBE complex did not influence milk composition, eating and ear surface temperature patterns, immune response, or metabolic parameters but promoted average milk yield throughout the experimental period. Additionally, a tendency of higher total antioxidant capacity and glutathione in the PGBE group was observed compared to the those in the control. When the temperature-humidity index (THI) exceeded 72 (average THI = 73.8), PGBE complex-fed cows experiencing heat stress showed increased milk yield and a tendency of increased rumination compared to the control. Conclusion: We suggest that incorporation of a combined mixture of 0.016% PGBE (1:1:1 ratio, vol/vol) to diet has the potential to improve milk yield and health status of cows under mild to moderate heat stress, denoting that it might be useful as an alternative anti-stressor in the diet of dairy cows under hot conditions.

• Resources Recycling
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• v.15 no.5 s.73
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• pp.17-25
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• 2006

Al-MCM-48 was used as a catalyst to decompose high density polyethylene(HDPE). Catalytic activity of Al-MCM-48 was compared with those of Al-MCM-41, Beta, and ZSM-5. Catalytic decomposition rate over Al-MCM-48 was much higher than at of non-catalytic pyrolysis only. Compared to other catalysts, Al-MCM-48 revealed the little higher activation energy value. The progressive deactivation behavior of the catalysts has also studied. ZSM-5 and Al-MCM-48 showed slower deactivation rates than Al-MCM-41 and Beta. Pyrolysis coupled with gas chromatographic separation and flame ionization detection (Py-GC/ FID) was also performed to assess the characteristics of pyrolysis products. ZSM-5 gave a higher fraction of gaseous products ($C_1-C_4$). Al-MCM-41 and Beta produced mainly $C_5-C_{12}$ products. The selectivity to oil product ($C_5-C_{22}$) obtained with Al- MCM-48 is higher an that with the other catalysts employed in this study.

• Journal of Korean Society of Environmental Engineers
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• v.37 no.4
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• pp.246-252
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• 2015

In steel factory, hot roller cleaning process produces a lot of iron oxide particles called as mill scale. Major components of these particles are wustite (FeO), magnetite ($Fe_3O_4$), and hematite ($Fe_2O_3$). In this study, we tried to produce pure magnetite from the mill scale because of the largest phosphate adsorption capacity of the magnetite. The mill scale was treated with acid (HCl+$H_2O_2$), base (NaOH), and acid-base ($H_2SO_4$+NaOH). Batch adsorption tests showed the acid and/or base treatment could increase the phosphate adsorption capacity of the iron oxides from 0.28 to over 3.11 mgP/g. Magnetite, which could be obtained by acid and base treatment of the mill scale, showed the best adsorption capacity. From the kinetic analysis, both Freundlich and Langmuir isotherm well described the phosphate adsorption behavior of the magnetite. In Langmuir model, maximum phosphate adsorption capacity was found to be 5.1 mgP/g at $20^{\circ}C$.

• Applied Chemistry for Engineering
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• v.19 no.5
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• pp.574-581
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• 2008

The optimum regeneration conditions for the regeneration of three way spent catalysts (TWCs), which were taken from automobiles with different driving conditions, were investigated to evaluate the suitability as alternative catalysts for removing VOCs. The spent catalysts were washed with five different acids ($HNO_3$, $H_2SO_4$, $C_2H_2O_4$, $C_6H_8O_7$, and $H_3PO_4$) to remove contaminants and examine the optimum conditions for recovering the catalytic activity. The physicochemical properties of spent and its regenerated TWCs were evaluated by using nitrogen adsorption-desorption isotherms, XRD, and ICP. The relative atomic ratios of contaminants and platinum group metals (PGMs) of the spent TWCs were greatly dependent on the placed positions. The main contaminants formed were lubricant oil additives and metallic components. Also, the regeneration treatment increased the PGMs ratio, BET surface area, and average pore diameter of TWCs. The catalytic activity results indicated that the spent TWCs have the possibility for removing VOCs. Moreover, the employed acid treatments greatly enhanced the catalytic activity of the spent TWCs. Especially, nitric and oxalic acids provided the most improvement in the catalytic behavior. The catalytic activities of the regenerated TWCs were significantly influenced by the containing platinum ratios rather than the removal ratios of contaminants and the changes in the structural properties offered by the acid treatments.

• Applied Chemistry for Engineering
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• v.5 no.4
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• pp.573-579
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• 1994

1-O-oleoyl glycerol, 2-O-oleoyl myo-inositol and methyl 2-O-oleoyl-${\alpha}$-D-glucopyranoside were used as surfactants in this study. The solution properties and solubilization process of those nonionic surfactants were examined by the phase equilibria. As a result of this study, we have found that phase behavior of two component systems of surfactants/$H_2O$/cyclohexane depends on temperature respectively. The three phase regions of three component systems appeared in the temperature range of $27^{\circ}C{\sim}32^{\circ}C$, $36^{\circ}C{\sim}45^{\circ}C$ and $38^{\circ}C{\sim}52^{\circ}C$ and solubilization of water and oil was high in those three phase ranged As the temperature was varied in the two component systems, liquid crystals of hexagonal were observed to in the case of 1-O-oleoyl glycerol, and liquid crystal of lamella types were observed in the case of 2-O-oleoyl myo-inositol and methyl 2-O-oleoyl-${\alpha}$-D-glucopyranoside.