• Journal of the Korean Society for Nondestructive Testing
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• v.31 no.5
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• pp.522-528
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• 2011

Artificial basilar membranes made of PVDF(polyvinylidene fluoride) are manufactured using microfabrication processes. The mechanical behavior of PVDF artificial basilar membrane was measured to evaluate its performance as a mechanical frequency analyzer using scanning LDV(laser Doppler vibrometer). The experimental setup consists of the microfabricated artificial basilar membrane, a loud speaker connected to an amplifier for generating acoustic pressure of specific spectral pattern, and a scanning LDV with controlling unit for measuring the displacement of the membrane on the incoming acoustic stimulation. The microfabricated artificial basilar membrane was attached tightly upon a package containing a chamber which can be filled with silicone oil before placed on the experimental setup stage. The experiment results showed that the microfabricated artificial basilar membrane has a property as a mechanical frequency analyzer.

• Membrane and Water Treatment
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• v.11 no.2
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• pp.97-109
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• 2020

Membrane fouling is the main drawback of membrane technology. Frequent membrane cleaning and membrane replacement are, therefore, required to reduce membrane fouling that causes permeate flux reduction, lower rejection, or higher operating pressure. Studies have proved that the alteration of membrane properties is the key controlling factor in lessening membrane fouling. Among stimuli-responsive membranes, thermo-responsive membrane is the most popular, with a drastic phase transition and swelling-shrinking behavior caused by the temperature change. In this study, the thermo-responsive ability of two commercial membranes, PolyCera® Titan membrane and PolyCera® Hydro membrane, at different temperatures was studied on the antifouling function of the membrane in palm oil mill effluent (POME) treatment. The evaluation of the membrane's thermo-responsive ability was done through three cycles of adsorption (fouling) and desorption (defouling) processes in a membrane filtration process. The experimental result depicted that PolyCera® Hydro membrane had a higher membrane permeability of 67.869 L/㎡.h.bar than PolyCera® Titan membrane at 46.011 L/㎡.h.bar. However, the high membrane permeability of PolyCera® Hydro membrane was compensated with low removal efficiency. PolyCera® Titan membrane with a smaller mean pore size had better rejection performance than PolyCera® Hydro membrane for all tested parameters. On the other hand, PolyCera® Titan membrane had a better hydrodynamic cleaning efficiency than PolyCera® Hydro membrane regardless of the hydrodynamic cleaning temperature. The best hydrodynamic cleaning performed by PolyCera® Titan membrane was at 35℃ with the flux recovery ratio (FRR) of 99.17 ± 1.43%. The excellent thermo-responsive properties of the PolyCera® Titan membrane could eventually reduce the frequency of membrane replacement and lessen the use of chemicals for membrane cleaning. This outstanding exploration helps to provide a solution to the chemical industry and membrane technology bottleneck, which is the membrane fouling, thus reducing the operating cost incurred by the membrane fouling.

• Journal of Pharmaceutical Investigation
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• v.33 no.2
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• pp.121-127
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• 2003

The objective of this study was to solidify the simvastatin self-microemulsifying drug delivery system (SMEDDS) and to improve the encapsulation efficiency of solidified alginate beads using sodium alginate. Typical simvastatin SMEDDS was composed of various oils, surfactants and cosurfactants. Also solidified-alginate beads was prepared by crosslinking liquid emulsion mixtures containing sodium alginate and other excipients (cetylpyridinum chloride (CP-Cl), hydroxypropyl methylcellulose, starch and so on). in $CaCl_2$ solution, it has been investigated that the drug release pattern and encapsulation efficiency were varied with the ratio of cationic lipid (CP-Cl). Solidified sodium alginate beads containing simvastatin SMEDDS were redispersed into media without re-aggregation. Oil droplet size of redispersed solidified-beads in media produced smaller than the initial size. The density of beads and drug loading amount were increased with increasing cationic lipid content. These systems have advantages of storage stability and predictability of drug release rate.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.7
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• pp.612-618
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• 2007

The dynamic behaviors of a KT-1 family aircraft nose landing gear have been analyzed and the optimal design of an aircraft shock absorber has been conducted to improve efficiency of shock energy absorption. The nose landing gear is modeled as a 2 DOF system using ADAMS and various operational and environmental landing conditions were considered. The results of dynamic simulation for various landing conditions agree well with experiments. Also the effect of parameters of a shock strut on the dynamic behaviors and on shock energy absorption of the nose landing gear has been evaluated for optimal design to define design variables. It has been found that the parameters of a shock strut such as oil-density and orifice area have more effects on dynamic behaviors than those of operation conditions. Optimal design is performed to maximize the efficiency of shock energy absorption using Feasible Direction Method. As a result the design values of the shock strut for maximum efficiency of shock energy absorption are derived and it turns out that efficiency and dynamic behaviors of the nose landing gear were improved by the optimal design.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.3
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• pp.211-221
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• 2020

This study aims to analyze the effect of structural Person-Organization Fit and organizational justice on organizational commitment, job satisfaction, Organizational Citizenship Behavior and employee performance. This study is based on a quantitative approach by collecting data using a survey conducted on three SOE's companies in Indonesia that operate in Makassar City, namely Pelindo. Ltd (Port Company), PLN. Ltd (Electric Company) and Pertamina. Ltd (Oil and Gas Company), with a sample of 90 employees. The study population was all non-managerial permanent employees. Data analysis using Structural Equation Modeling. In structural relations, out of the nine direct tests, there were two insignificant relationships, and in all three hypotheses there was one not-supported hypothesis. When compared between person-organization Fit and Organizational Justice, it is found that organizational justice has a more critical role in building Human Resource performance compared to Person-Organization Fit, because organizational justice is better able to provide job satisfaction and make organizational commitment and OCB as a prerequisite for its formation to better Human Resources performance. With organizational justice, employees will feel more satisfied working, committed to the work and organization, and behaves as a supportive organizational citizen for the realization of the best performance for the interests of the organization going forward.

• Structural Engineering and Mechanics
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• v.49 no.4
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• pp.427-448
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• 2014

At present, the time of easy oil and gas is over. Now, the largest part of fossil fuels is concentrated in the deepest levels of tectonic structures and in the sea shelves. One of the most cumbersome operations of their extraction is the bore-hole drilling. In connection with austere tectonic and climate conditions, their drivage every so often is associated with great and diversified technological difficulties causing emergencies on frequent occasions. As a rule, they are linked with drill string accidents. A key role in prediction of these situations should play methods of theoretical modelling. For this reason, there is a growing need for development and implementation of new numerical methods for computer simulation of critical and post-critical behavior of drill strings (DSs). In this paper, the processes of non-linear deforming of a DS in cylindrical cavity of a deep bore-hole are considered. On the basis of the theory of curvilinear flexible rods, non-linear constitutive differential equations are deduced. The effects of the longitudinal non-uniform preloading, action of torque and interaction between the DS and the bore-hole surface are taken into account. Owing to the use of curvilinear coordinates in the constraining cylindrical surface and a specially chosen concomitant reference frame, it became possible to separate the desired variables and to reduce the total order of the equation system. To solve it, the method of continuation the solution by parameter and the transfer matrix technique are applied. As a result of the completed numerical analysis, the critical states of the DS loading in the cylindrical channels of inclined bore-holes are found. It is shown that the modes of the post-critical deforming of the DS are associated with its irregular spiral curving prevailing in the zone of bottom-hole-assembly. The possibility of invariant state generation during post-critical deforming is established, condition of its bifurcation is formulated. It is shown that infinite variety of loads can correspond to one geometrical configuration of the DS. They differ each from other by contact force functions.

• Archives of Pharmacal Research
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• v.28 no.6
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• pp.736-742
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• 2005

Xyloglucan (XG), which exhibits thermal sol to gel transition, non-toxicity, and low gelation concentration, is of interest in the development of sustained release carriers for drug delivery. Drug-loaded XG beads were prepared by extruding dropwise a dispersion of indomethacin in aqueous XG solution (2 wt.-$\%$) through a syringe into corn oil. Enteric coating of XG bead was performed using Eudragit L 100 to improve the stability of XG bead in gastrointestinal (GI) track and to achieve gastroresistant drug release. Release behavior of indomethacin from XG beads in vitro was investigated as a function of loading content of drug, pH of release medium, and concentration of coating agent. Adhesive force of XG was also measured using the tensile test. Uniform-sized spherical beads with particle diameters ranging from 692 $\pm$ 30 to 819 $\pm$ 50 $\mu$m were obtained. The effect of drug content on the release of indomethacin from XG beads depended on the medium pH. Release of indomethacin from XG beads was retarded by coating with Eudragit and increased rapidly with the change in medium pH from 1.2 to 7.4. Adhesive force of XG was stronger than that of Carbopol 943 P, a well-known commercial mucoadhesive polymer, in wet state. Results indicate the enteric-coated XG beads may be suitable as a carrier for oral drug delivery of irritant drug in the stomach.

• Journal of ILASS-Korea
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• v.6 no.1
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• pp.18-24
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• 2001

Liquid fossil fuel contaminated by water can cause trouble in the combustion processes and affect the endurance of a combustion system. Using an optical sensor to monitor the water content instantaneously in a fuel pipeline is an effective means of controlling the fuel quality in a combustion system. In two component liquid flows of oil and water, the flow pattern and characteristics of water droplets are changed with various flow conditions. Additionally, the light scattering of the optical sensor measuring the water content is also dependent on the flow patterns and droplet characteristics. Therefore, it is important to investigate the detailed behavior of water droplets in the pipeline of the fuel transportation system. In this study, the flow patterns and characteristics of water droplets in the turbulent pipe flow of two component liquids of gasoline and water were investigated using optical measurements. The dispersion of water droplets in the gasoline flow was visualized, and the size and velocity distributions of water droplets were simultaneously measured by the phase Doppler technique. The Reynolds number of the gasoline pipe flow varied in the range of $4{\times}10^{4}\;to\;1{\times}10^{3}$, and the water content varied in the range of 50 ppm to 300 ppm. The water droplets were spherical and dispersed homogeneously in all variables of this experiment. The velocity of water droplets was not dependent on the droplet size and the mean velocity of droplets was equal to that of the gasoline flow. The mean diameter of water droplets decreased and the number density increased with the Reynolds number of the gasoline flow.

• Journal of the Korean Dietetic Association
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• v.6 no.2
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• pp.86-96
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• 2000

Food service management without nutrition education in school foodservice is hardly to improve nutritional status of school children. Therefore, this study was attempted to evaluate the effectiveness of nutrition education. The nutrition education was done for 82 5th grade children of 2 elementary school in Inchon. It has been performed for two month from Sep. 6 to Nov. 11, 1999. Also, to evaluate the effects of nutrition education, subjects were taken pretest for food habit, attitude, nutrition knowledge, and dietary intake through the questionnaires. The statistical analysis of data was completed using SPSS program. The results were summarized as follows : 1) The average height and weight for subjects are 141cm and 34.4kg. Most of the subjects had 2 siblings. 83.8% of the subjects has never been taken nutrition education. Otherwise, 85.2% of the subjects responded that they need a nutrition education. 2) For the food habit test results, the posttest mean scores increased. Food habit on vegetables showed significant difference between pretest and posttest(p<0.05). 3) The attitude test did not show the significant difference between pretest and posttest. 4) For the nutrition knowledge test result, the pre and posttest means were 47.59 and 57.12 respectively(p<0.001). 5) The correlations of food habit, attitude, and nutrition knowledge was positive relationship between food habit and attitude in the pre and posttest. 6) Intake frequency of foods increased for the most foods except meat, egg, milk, and drink as compaired pretest with posttest. Cereal, fish, and oil intake was significantly increased. 7) The intakes of most nutrients were increased, among which carbohydrate, fiber, calcium, and vitamin C intakes significantly different after education. The education period of this study was too short to improve their eating behavior and food choice and may need a long-term education and development of materials for nutrition education.

• Journal of Korean Society of Transportation
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• v.28 no.4
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• pp.61-73
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• 2010

This research is to analyze reasons for violation of the Self Carfree day policy. It also analyzes satisfaction of the policy participation incentives. The results are that the violation rate is increasing if the drivers live in a zone which is highly energy consuming, which has low potential demand per bus stop and low trip generation per number of houses, which therefore requires more bus routes and bus services, and in which the drivers pay more car operating fees and show less tendancy towards participation even with the 5-10% oil price increase. The results are significant at the 0.05 level.