• Journal of Wetlands Research
• /
• v.16 no.1
• /
• pp.125-137
• /
• 2014

In this study, that the Kraven(II) empirical formula, the existing method to estimate the time of concentration in river basin, does not reflect the characteristics of relevant basin as it presents 3 stream velocities by section of slope was verified, and the time of concentration for the actual average stream velocity considering the characteristics of the basin was compared and analyzed by applying the continuous Kraven empirical formula, which was suggested recently by 'Design Flood Estimation Guide Line, 2012, Ministry of Land, Transport and Maritime Affairs' complementing the stream velocities for the easy slope and the steep slope, to the Donghwa-Cheon, the medium size river and the modality of changes in hydrograph was examined, For the Maeho-Cheon, Wuksu-Cheon and Geumpo-Cheon, the flood runoff simulation results according to the time of concentration application empirical formula considering the characteristics of relevant basin were compared and analyzed and following conclusions were able to obtain.

• Korean Journal of Human Ecology
• /
• v.17 no.5
• /
• pp.1001-1013
• /
• 2008

The purpose of this study were to make clear the actual state of indoor air quality by cooling in private institute classrooms and to analyze influencing factors on indoor air quality. The measurements of physical elements and observations of architectural characteristics and living conditions were carried out in each 1 classroom of 5 private institutes. Measuring elements were indoor temperature, relative humidity, $PM_{10}$, HCHO, CO, and $CO_2$ concentration. As results, the averages of indoor temperature each classroom were $21.7\sim28.1^{\circ}C$. 3 classrooms were lower than the Maintenance standard($26\sim28^{\circ}C$) of School Health Law. The means of relative humidity were 48$\sim$63%, all classrooms were ranged within the standard(30$\sim$80%). The means of $PM_{10}$ concentration were 2.1 $\sim$ 17 $\mu g/m^3$, all classrooms were kept within the standard(100 $\mu g/m^3$). The means of HCHO concentration were 0.02$\sim$0.16 ppm, 2 classrooms were exceed the standard(0.1 ppm). The means of CO concentration were 1.4$\sim$3.6 ppm, all classrooms were kept within the standard(10ppm). The means of $CO_2$ concentration were 1,593$\sim$3,819 ppm, all classrooms were exceed the standard(1,000ppm). The results of analysis on influencing factors of the physical elements are as follow; the air conditioner set of temperature, personal necessities like hair spray, teacher's smoking in corridor, windows and doors opening time, the number of students, and volume of classroom.

• Advances in environmental research
• /
• v.5 no.3
• /
• pp.189-200
• /
• 2016

This study aimed at advanced oxidation of hetero tri-functional reactive dye Acid orange 7 using photo-Fenton conditions in a lab-scale experiment. Decolourisation of Acid Orange 7 dye by Fenton's process was dependent on concentration of Hydrogen peroxide, Ferrous sulphate, pH, and contact time. A $2^3$ factorial design was used to evaluate the effects of these key factors: pH, Fe(II), and $H_2O_2$ concentration, for a dye concentration of 50 mg/L with COD of 340 mg/L at pH 3.0. The response function was removal of colour under optimised conditions; pH 3.0, [Fe(II)] 40.83 mg/L, [$H_2O_2$] 4.97 mmol/L; 13.6 min. of treatment resulting in 100% colour removal. The final COD of treated wastewater was nil suggesting that AOP is a potentially useful process of color removal and dye degradation/mineralisation of effluent having AO7. Minimum contact time for complete decolourisation was at 5 mmol/l $H_2O_2$ concentration. Increase in $FeSO_4$ (mg/l) concentration resulted in decrease of time for complete decolourisation. Box-Behnken Design was used to optimize the process variables. Maximum and minimum levels of pH (3-5), $H_2O_2$ (4-6 mmol/l), $FeSO_4$ (30-46 mg/l) and contact time (5-15 minutes) were used. The statistical analysis revealed a value of 0.88 for coefficient of regression ($R^2$) indicating a good fit of model. Calculated F-value was found higher than the tabulated value confirming to significance of the model. Based on student's t-test, Ferrous sulphate, pH, and contact time have a positive effect on the percent decolourisation of Acid Orange 7.

• Journal of Korean Society on Water Environment
• /
• v.26 no.1
• /
• pp.35-43
• /
• 2010

This experimental design and response surface methodology (RSM) have been applied to the investigation of the electrocoagulation/flotation of dye wastewater. The electrocoagulation/flotation reactions were mathematically described as a function of parameters current (A), NaCl concentration (B), initial RhB concentration (C) and time (D) being modeled by use of the central composite design (CCD). The application of RSM using the CCD yielded the following regression equation, which is an empirical relationship between the RhB removal (%) and test variables in RhB removal (%) = $-300.42+129.21{\cdot}Current+46.99{\cdot}NaCl-0.11{\cdot}RhB-+43.71{\cdot}Time-5.67{\cdot}Current{\cdot}NaCl-3.18{\cdot}Current{\cdot}Time-2.41{\cdot}NaCl{\cdot}Time-19.79{\cdot}Current^2-2.27{\cdot}NaCl^2-1.59{\cdot}Time^2$. the model predictions agreed well with the experimentally observed result ($R^{2}=0.9728$). The estimated ridge of maximum response and optimal conditions for RhB removal (%) using canonical analysis was 99.4% (A: 1,77 A, NaCl concentration: 2.23 g/L, RhB concentration: 56.12 mg/L, Time: 9.98 min). To confirm this optimum condition, three additional experiments were performed and RhB removal (%) were within range of 86.87% (95% PI low)~111.93% (95% PI high) obtained.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.28 no.3_4
• /
• pp.460-471
• /
• 2004

The purpose of this study is to investigate the effect of hair-style (straight and wave), hair-length(short, medium, and long), and type of hat design (no-hat, beret, cloche, bowler, and capeline) on impression formation. The experimental materials developed for this study were a set of stimulus and response scales. The 7-point semantic differential response scales were designed. Thirty stimuli color pictures of various combination of hair length, hair style, and type of hat design were manipulated by computer drawing. The subjects were 360 undergraduates living in Seoul, Kyunggi and Kyungnam. The experimental design was composed of 3 factorial designs. The result of the study can be summarized as follows; Impression factor of the stimulus consisted of the 5 different dimensions (attractiveness, gracefulness, activity, concentration of attention, cuteness). Hair style greatly affected gracefulness. On the other hand, hair length made remarkable effects on attractiveness, concentration of attention, and cuteness. In addition, it has been found that the type of hat design significantly influenced on all the factors except attractiveness as independent variables. In regarding the effect of interaction between each variable, the combination of hair style and hair length had significant effects on gracefulness. In the impression formation of cuteness, the combination of hair length and type of hat design were more significant.

• Preventive Nutrition and Food Science
• /
• v.14 no.2
• /
• pp.129-133
• /
• 2009

Salicornia herbacea is rich in natural minerals, dietary fibers, and potentially health-promoting phenolic compounds. In this paper, an experimental design was applied for the optimization of the ultrasound-assisted extraction of phenolic compounds from lyophilized Salicornia herbacea powder. The experiments were conducted in accordance with a five-level, three-variable central composite rotatable design (CCRD), and the effects of solvent concentration, extraction time, and extraction temperature were evaluated via response surface methodology (RSM). The optimal extraction conditions were as follows: ethanol concentration, 76.80%; extraction time, 20 min; and extraction temperature, $33.21^{\circ}C$; and the solvent concentration was the most significant parameter in this process, under which the predicted total phenolic content was 49.91 mg GAE/g sample.

• Environmental Engineering Research
• /
• v.15 no.3
• /
• pp.129-134
• /
• 2010

The optimization of experimental parameters, such as catalyst type, catalyst concentration, molar ratio of alcohol to oil and reaction temperature, on the transesterification for the production of rapeseed methyl ester has been studied. The Taguchi approach (Taguchi method) was adopted as the experimental design methodology, which was adequate for understanding the effects of the control parameters and to optimize the experimental conditions from a limited number of experiments. The optimal experimental conditions obtained from this study were potassium hydroxide as the catalyst, at a concentration of 1.5 wt %, and a reaction temperature of $60^{\circ}C$. According to Taguchi method, the catalyst concentration played the most important role in the yield of rapeseed methyl ester. Finally, the yield of rapeseed methyl ester was improved to 96.7% with the by optimal conditions of the control parameters which were obtained by Taguchi method.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.18 no.3
• /
• pp.707-715
• /
• 1994

This study presents thickness optimization for the pressure vessel domes subject to internal pressure and axial force simultaneously. The considered typical pressure vessel domes are ellipsoidal and tori-spherical domes with skirt and nozzle part. These pressure vessel domes under loading have higher stress concentration on geometric discontinuity parts. Therefore, thickness optimization of axi-symmetric pressure vessel domes is essentially concerned on minimizing this stress concentration. The objective function is minimization of weight of pressure vessel dome. The design variable is thickness of dome and cylinder. Considered constraint is Von Mises equivalent stress. In the optimization procedure, ANSYS code is used. The equivalent and hoop stress of original shape domes are compared with those of optimal shape domes. And optimal thicknesses for pressure vessel domes are presented.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
• /
• 2001.05a
• /
• pp.121-124
• /
• 2001

Using ordors with the different concentration of essential oils, e studied the effect of a pleasant olfactory stimulation on physiological responses. we examined psychological response, mental task and changes in cardiac, immunity and EEG in responses to 150times solution (feel easily) and 500times solution (feel with difficulty) which of essential oil (called PCK) were diluted in propylene glycol, and neutral (water). The 150times solution that was felt pleasant produced significant differences (p<0.05) in relative power change of beta activity in the left frontal region (Fp1, F3, F7) of the brain, and heart rate (HR) deceleration after mental task. these results are consistent with substantial research that has documented cardiac and EEG responses to pleasant stimuli. What is more, 150times solution increased the concentration of s-IgA know as an index of immunity.

• Proceedings of the Korean Society of Dyers and Finishers Conference
• /
• 2012.03a
• /
• pp.51-51
• /
• 2012

Cellulose is extremely difficult to dissolve cellulose in water and most common organic solvents due to their stiff molecular structure, close chain packing and intermolecular hydrogen bonds. Recently, cellulose solutions using ionic liquids (ILs) as a green solvent have been known to form cholesteric liquid crystalline phase at high cellulose concentration. In this study, the phase transition and rheological behaviors of concentrated cellulose/[AMIM]Cl solution were investigated using polarized optical microscopy and rheometry. Studies were conducted to characterize the influence of cellulose concentration on the phase transition of the cellulose solution and the mechanical properties of the regenerated fibers spun from the anisotropic cellulose/[AMIM]Cl solutions.