• Membrane Journal
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• v.13 no.1
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• pp.20-28
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• 2003

In this study, we try to formularize simultaneous equations to make a prediction about pressure drop for designing intravascular artificial lung assist device. Designing parameters to predict the effect of pressure drop and designed modules under various conditions were studied through an experimental modeling before inserting the artificial lung assist device into as venous. We measured pressure drop in various number of hollow fiber membranes, when the inside diameter of shell is fixed in 3 cm, and tried to develope the prediction equations by curve fitting based on the correlation between the experimental pressure drop and the device frontal area or packing density. The results showed that pressure drop increased with 2nd order functional formula as the liquid flow rate, the frontal area, and the packing density increased. Also, we can estimate the pressure drop as a function of the frontal area or packing density. The pressure drop obtained from the experiment was similar to that from the equation, confirming the usefulness of the equation.

• Archives of Pharmacal Research
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• v.23 no.5
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• pp.507-512
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• 2000

This study set out to improve the physical and pharmaceutical characteristics of the present formulation using an appropriate experimental design. The work described here concerns the formulation of the dispersible tablet applying direct compression method containing roxithromycin in the form of coated granules. In this study $2^3$ factorial design was used as screening test model and Central Composite Design (CCC) associated with response surface methodology was used as optimization study model to develop and to optimize the proper formulation of roxithromycin dispersible tablet. The three independent variables investigated were functional excipients like binder (X1), disintegrant (X2) and lubricant (X3). The effects of these variables were investigated on the following responses: hardness (Y1), friability (Y2) and disintegration time (Y3) of tablet. Three replicates at the center levels of the each design were used to independently calculate the experimental error and to detect any curvature in the response surface. This enabled the best formulations to be selected objectively. The effect order of each term to all response variable was X3> X2> Xl> X1＊X2> X2＊X2> X2＊X3> X3＊X3> Xl＊X3> Xl＊Xl and model equations on each response variables were generated. Optimized compositions of formula were accordingly computed using those model equations and confirmed by following demonstration study. As a result, this study has demonstrated the efficiency and effectiveness of using a systematic formulation optimization process to develop the tablet formulation of roxithromycin dispersible tablet with limited experiment.

• Ocean Systems Engineering
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• v.7 no.2
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• pp.143-155
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• 2017

For complex flexible structures such as nets, the determination of drag forces and its deformation is a challenging task. The accurate prediction of loads on cages is one of the key steps in designing fish farm facilities. The basic physics with a simple cage, can be addressed by the use of experimental studies. However, to design more complex cage system for various environmental conditions, a reliable numerical simulation tool is essential. In this work, the current load on a cage is calculated using a Morison-force model applied at instantaneous positions of equivalent-net modeling. Variations of solidity ratio ($S_n$) of the net and current speed are considered. An equivalent array of cylinders is built to represent the physical netting. Based on the systematic comparisons between the published experimental data for Raschel nets and the current numerical simulations, carried out using the commercial software OrcaFlex, a new formulation for $C_d$ values, used in the equivalent-net model, is presented. The similar approach can also be applied to other netting materials following the same procedure. In case of high solidity ratio and current speed, the hybrid model defines $C_d$ as a function of Re (Reynolds number) and $S_n$ to better represent the corresponding weak diffraction effects. Otherwise, the conventional $C_d$ values depending only on Re can be used with including shielding effects for downstream elements. This new methodology significantly improves the agreement between numerical and experimental data.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.27 no.6
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• pp.443-451
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• 2015

Design formula for estimating the wave loading on the perforated caisson having two wave chambers is yet available. In this study, the analysis results are presented with the experimental data for the wave force acting on such a breakwater model. Based on the experimental results, it was able to clarify the variation of wave action according to five different wave phases that are associated with peak wave loading at the three vertical walls. Then the force adjustment factor for double-chamber caisson was estimated, similarly as Takahashi and Shimosako (1994), which needs to be further validated with subsequent experiments and practical application in the field.

• Steel and Composite Structures
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• v.21 no.6
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• pp.1227-1250
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• 2016

Most of the research work has been conducted on K-joints under static loading. Very limited information is available in consideration of fatigue strength of K-joints with concrete-filled chord. This paper aims to describe experimental and numerical investigations on stress concentration factors (SCFs) of concrete-filled circular chord and square braces K-joints under balanced axial loading. Experiment was conducted to study the hot spot stress distribution along the intersection of chord and braces in the two specimens with compacting concrete filled in the chord. The test results of stress distribution curves of two specimens were reported. SCFs of concrete-filled circular chord and square braces K-joints were lower than those of corresponding hollow circular chord and square brace K-joints. The corresponding finite element analysis was also conducted to simulate stress distribution along the brace and chord intersection region of joints. It was achieved that experimental and finite element analysis results had good agreement. Therefore, an extensive parametric study was carried out by using the calibrated finite element model to evaluate the effects of main geometric parameters and concrete strength on the behavior of concrete-filled circular chord and square braces K-joints under balanced axial loading. The SCFs at the hot spot locations obtained from ABAQUS were compared with those calculated by using design formula given in the CIDECT for hollow SHS-SHS K-joints. CIDECT Design Guide was generally quite conservative for predicting SCFs of braces and was dangerous for predicting SCFs of chord in concrete-filled circular chord and square braces K-joints. Finally SCF formulae were proposed for circular chord and square braces K-joints with concrete-filled in the chord under balanced axial loading. It is shown that the SCFs calculated from the proposed design equation are generally in agreement with the values derived from finite element analysis, which were proved to be reliable and accurate.

• Journal of the Korean Geosynthetics Society
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• v.22 no.4
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• pp.27-34
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• 2023

This paper describes the results of a pile pullout test considering the confine pressure and fines content of the ground. The Pullout tests were conducted under various ground conditions using model piles. The effect of ground confine pressure on the pullout resistance and the pullout resistance parameters of the pile were evaluated based on the experimental results. The results of pullout test showed that the maximum pullout resistance occurred at a pullout displacement of about 7mm to 9mm, regardless of the fines content and the confine pressure of the ground. The maximum pullout resistance of the pile decreased as the fines content of the ground increased, and this trend became clearer as the confine pressure increased. The pullout resistance calculated by theoretical formula was compared with the experimental results in order to ensure the reliability of the pullout test results. The comparative results showed that the experimental and theoretical values showed a tendency to decrease the pullout resistance as the fines content increased, in all confine pressure conditions. The analysis result of the pullout resistance parameters confirmed that the pullout resistance was greatly influenced by the adhesion compared to the interface friction angle, as the fines content of the ground around the pile increased.

• Herbal Formula Science
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• v.26 no.1
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• pp.13-26
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• 2018

Objectives : This study was carried out to enhance the activity of Iksuyoungjingo, which has the tonify Qi, nourish Yin effect of oriental medicine, and to study the effect of the prescriptions on the immunological activities. Methods : Immunosuppression was induced by methotrexate (MTX) 2 mg / kg, the experimental group was divided into IYGgami-I, IYGgami-I-F, IYGgami-II and IYGgami-II-F groups. Each prescription was administered with drinking water for 20 days, and body weight was measured every 5 days during this period. Leukocyte, $TNF-{\alpha}$, IL-2, IL-6, IgE, spleen weight and body weight were measured Results : In the changes of $TNF-{\alpha}$, IL-2 and IL-6 as pro-inflammatory elements, all of the experimental groups showed a significant increase compared to the control group. In the IgE changes, the IYGgami-I-F, IYGgami-II and IYGgami-II-F groups showed a significant decrease compared to the control group. In the changes of spleen weight, the IYGgami-II-F group showed a significant increase compared to the control group. In the changes of WBC and lymphocytes, the IYGgami-I-F group showed a significant increase compared to the control group. Conclusions : From the above results, it can be observed that the efficacy against immunity is exerted in all of the preparations, and it was confirmed that the efficacy was maintained constant even when utilizing the Rehmannia glutinosa Residue and Poria cocos Bark, and that a more beneficial effect can be exerted in the effectiveness when the fermentation is carried out.

• Journal of Physiology & Pathology in Korean Medicine
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• v.32 no.4
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• pp.255-260
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• 2018

Chung-Sang (CS) is an experimental herbal remedy that is formulated to treat respiratory diseases implicated by inflammation. The herbs comprised of CS are frequently prescribed for treating various inflammatory symptoms: Menthae haplocalycis Herba, Magnoliae Flosis, Xanthii Fructus, Herba Asari, and Caryphylli Flos. Here, we prepared the extract of CS with boiling water (wCS) or with 50 % ethanol (eCS) and examined whether the two different extracts of CS exhibit a toxicity to cultured cells and mice. RAW 264.7 cells were treated with wCS or eCS, and the cytotoxicity of these extracts to RAW 264.7 cells was determined by an MTT assay. Although the production of intracellular reactive oxygen species that are detrimental to the cells was not increased by the extracts, the cytotoxicity to the cells was evident from 10 mg/ml of wCS and 100 mg/ml of eCS, suggesting that eCS is less cytotoxic. When mice (n = 10/group) received a single intratracheal wCS or eCS daily for 14 days, wCS yielded 40 % mortality, whereas eCS showed none. Both wCS and eCS did not significantly affect the weight of the body and of vital organs, except the lung. Biochemical analyses of mice blood indicated no damage to liver or kidney. However, unlike eCS, wCS significantly increased the level of IgE in serum. Collectively, our results show that eCS was less toxic than wCS, suggesting that CS prepared with 50 % ethanol is preferential over the conventional way of preparing CS.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.5
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• pp.1777-1783
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• 2013

Parshall flume is more practical one of hydraulic structures for measuring flowrate in open channels and also has more advantages when the magnitude of flow velocity is relatively lower or much more sediments are brought from upstream. International Organization for Standardization (ISO) has suggested the empirical formulas standardized by the sizes and dimensions of Parshall flume. However, the related studies using the numerical simulations and experiments are relatively rare. Therefore, in this study, it was examined whether the numerical simulation was adequacy for reproducing the hydraulic characteristics of Parshall flume as much as laboratory experiments by comparing the results from numerical simulations and empirical equation. And for arbitrary Parshall flume, that is unlisted in the ISO standards due to environmental conditions, constructional difficulties etc, thus, the hydraulic experiments should be conducted to obtain the empirical formulas for it, the results from numerical simulations were compared with those of laboratory experiments. Consequently, it was convinced that the numerical simulation about Parshall flume was simulated appropriately instead of experimental approach. And the dimensionless discharge equation of arbitrary ones was suggested using the results of numerical simulations, and the equation was validated by comparing with laboratory experimental results showing the maximum relative error of 2.3%. If the actual topography, the shape of inlet and submerged flow, which is excluded in this study, were carefully considered, it would be possible to supply a simple empirical discharge equation based on numerical results. Also, it can replete hard works for hydraulic experiment being error-prone with complex procedures to a minimum of economic effort.

• Herbal Formula Science
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• v.6 no.1
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• pp.119-139
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• 1998

This study was to investigate the protective and effects of Ikgukwhan and Ikgukbowhawhan on the liver cirrhosis or fibrosis induced by prolonged bile duct ligation; a new experimental model for cirrhosis and the intraperitoneal injection of dimethylnitrosamine in the rat. The development of fibrosis or cirrhosis and its inhibition by the two prescriptions were examined by the chemical analysis of AST, ALT, and hydroxyproline. The results obtained were as follows. 1. The increase of serum asparate aminotransferase induced by bile ductligation was inhibited by the administration of Ikgukwhan and Ikgukbowhawn extract. 2. The increase of serum alanine aminotransferase induced by bile duct ligation was inhibited by the administration of Ikgukwhan and Ikgukbowhawhan extract. 3. The increase level of serum AST and ALT induced by the intraperitoneal injection of dimethylnitrosamine was inhibited by the administration of Ikgukwhan and Ikgukbowhawhan extract. 4. The increase level of hydroxyproline volume in the damaged liver tissues in the rat was decreased by the oral administration of Ikgukwhan and Ikgukbowhawhan extract. But there were no significant differences in the inhibition rate between the two experimental groups.