• Food Science and Biotechnology
• /
• v.17 no.2
• /
• pp.379-383
• /
• 2008

Extraction characteristics of garlic and functional properties of corresponding extract were monitored by response surface methodology (RSM). Maximum extraction yield of 26.41% was obtained at microwave power of 146.29 W, ethanol concentration of 63.31 %, and extraction time of 5.88 min. At microwave power, ethanol concentration, and extraction time of 114.84 W, 58.83%, and 1.42 min, respectively, maximum electron-donating ability (EDA) was 72.86%. Maximum nitrite-scavenging ability was 94.62% at microwave power, ethanol concentration, and extraction time of 81.83 W, 2.65%, and 3.83 min, respectively. Superoxide dismutase (SOD) showed maximum pseudo-activity of 49.12% at microwave power of 34.23 W, ethanol concentration of 33.11 %, and extraction time of 4.40 min. Based on superimposition of 4-dimensional RSM with respect to extraction yield, electron-donating ability, nitrite-scavenging ability, and pseudo-activity of SOD, optimum ranges of extraction conditions were microwave power of 0-100 W, ethanol concentration of 40-70%, and extraction time of 2-8 min.

• Journal of the Korean Society for Precision Engineering
• /
• v.22 no.1
• /
• pp.167-174
• /
• 2005

The design for cold extrusion dies is very important, because the die insert is subjected to very high radial and hoop stresses. The design of cold extrusion dies has many constrained conditions. In this paper, the used assumptions are such that the yield strength of each ring is selected according to the allowable tensile or compressive hoop stress in each ring and the maximum allowable inner pressure, when yielding occurs in one ring of the dies, is obtained by the proposed equation. In order to obtain design variables, such as diameter ratios and interferences, using the maximum inner pressure, the flexible tolerance method was used for shrink-fitted thick-walled cylinders. ANSYS APDL was used to perform the repeated analysis of deformation of the dies due to the variation of the design variables. The response surface methodology is utilized to analyze the relationship between the design variables and the maximum radial displacement of the die insert during extrusion. From the results, it is found that outer diameter of the die insert has the largest effect on the minimization of maximum radial displacement at the inner surface of the dies.

• Journal of the Korean Society for Precision Engineering
• /
• v.25 no.10
• /
• pp.137-143
• /
• 2008

The objective of this study was to characterize the role of synovial fluid and hyaluronan in the frictional response of bovine articular cartilage. Seven cylindrical cartilage specimens were harvested from three fresh bovine humoral heads (4-6 months old). Reciprocal sliding motion (1mm/s) was provided by a custom-made friction testing apparatus with a normal load of 22.3 N. From the measured time-dependent normal and frictional forces, the minimum and maximum frictional coefficients were calculated. Synovial fluid reduced the minimum frictional coefficient by ${\sim}75$ % and maximum frictional coefficient by ${\sim}11%$, while the reduction of the minimum and maximum frictional coefficients with hyaluronan was ${\sim}42%$ and ${\sim}24%$, respectively. To the best of our knowledge, this experimental study investigates the first such comparisons of frictional response of articular cartilage with and without synovial fluid and hyaluronan, and provides significant insights into their role in the articular cartilage friction and lubrication.

• Computers and Concrete
• /
• v.16 no.3
• /
• pp.429-448
• /
• 2015

The dams are huge structures storing a large amount of water and failures of them cause especially irreparable loss of lives during the earthquakes. They are named as a group of structures subjected to fluid-structure interaction. So, the response of the fluid and its hydrodynamic pressures on the dam should be reflected more accurately in the structural analyses to determine the real behavior as soon as possible. Different mathematical and analytical modelling approaches can be used to calculate the water hydrodynamic pressure effect on the dam body. In this paper, it is aimed to determine the dynamic response of concrete gravity dams using different water modelling approaches such as Westergaard, Lagrange and Euler. For this purpose, Sariyar concrete gravity dam located on the Sakarya River, which is 120km to the northeast of Ankara, is selected as a case study. Firstly, the main principals and basic formulation of all approaches are given. After, the finite element models of the dam are constituted considering dam-reservoir-foundation interaction using ANSYS software. To determine the structural response of the dam, the linear transient analyses are performed using 1992 Erzincan earthquake ground motion record. In the analyses, element matrices are computed using the Gauss numerical integration technique. The Newmark method is used in the solution of the equation of motions. Rayleigh damping is considered. At the end of the analyses, dynamic characteristics, maximum displacements, maximum-minimum principal stresses and maximum-minimum principal strains are attained and compared with each other for Westergaard, Lagrange and Euler approaches.

• Journal of Korean Association for Spatial Structures
• /
• v.22 no.1
• /
• pp.33-40
• /
• 2022

When the center of stiffness and the center of mass of the structure differ under the seismic load, torsion is caused by eccentricity. In this study, an analysis model was modeled in which the positions of the core and the plane rotation axis of a 60-story torsional atypical structure with a plane rotation angle of 1 degree per floor were different. The structural behavior of the analysis model was analyzed, and the earthquake response behavior of the structure was analyzed based on the time history analysis results. As a result, as the eccentricity of the structure increased, the eccentricity response was amplified in the high-rise part, and the bending and torsional behavior responses were complex in the low-order vibration mode. As a result of the analysis, the maximum displacement and story drift ratio increased due to the torsional behavior. The maximum story shear force and the story absolute maximum acceleration showed similarities for each analysis model according to the shape of the vibration mode of the analysis model.

• Wind and Structures
• /
• v.37 no.3
• /
• pp.245-254
• /
• 2023

In this paper, the wind-induced response of Jiayuguan wooden building (world cultural heritage) in Northwest China was studied. ANSYS finite element software was used to establish four kinds of building models under different working conditions and carry out modal analysis. The simulation results were compared with the field dynamic test results, obtaining the model which reflects the real vibration characteristics of the wooden tower. Time history data of fluctuating wind speed was obtained by MATLAB programming. Time domain method and ANSYS were used to analyze the wind-induced vibration response time history of Jiayuguan wooden building, obtaining the displacement time history curve of the structure. It was suggested that the wind-induced vibration coefficient of Jiayuguan wooden building is 1.76. Through analysis of the performance of the building under equivalent static wind load, the maximum displacement occurs in the three-story wall, gold column and the whole roof area, and the maximum displacement of the building is 5.39 cm. The ratio of the maximum stress value to the allowable value of wood tensile strength is 45 %. The research results can provide reference for the wind resistant design and protection of ancient buildings with similar structure to Jiayuguan wooden tower.

• Journal of the Korean Applied Science and Technology
• /
• v.21 no.2
• /
• pp.148-155
• /
• 2004

Response surface analysis was used to study dietary ratios of n-3/n-6 fatty acid and P/S to minimize plasma triglycerides, total cholesterol and LDL ${\cdot}$ VLDL-C levels and maximize plasma HDL ${\cdot}$ C levels of rats. Because the dietary components were not statistically independent, they were studied in combinations of two variables. The two-variable combinations were the most useful in locating the desired maximum or minimum plasma triglycerides, total cholesterol and LDL ${\cdot}$ VLDL-C response in terms of the proportions of the dietary components. Response surface contours and three dimensional plots were developed for each plasma lipid response. The contours and three dimensional plots were used to help determine those combinations of the dietary fatty acid ratios that would produce the desired minimum or maximum lpid responses. The statistical analyses indicated that the minimized plasma cholesterol response levels could be attained with a diet consisting of 2.26 n-3/n-6 fatty acid and 2.15 P/S ratios.

• Journal of the Korea Computer Industry Society
• /
• v.2 no.9
• /
• pp.1155-1162
• /
• 2001

This paper proposes a method to determine the optimal utilizations of the UNIX systems. This method is developed using the definition-the optimal utilization is the maximum allowable utilization In other words, the optimal utilization is the maximum utilization that can be allowed by users while providing tolerable response time. As the tolerable response time increases, the optimal utilization increases. Therefore, the optimal utilization is obtained at the maximal value of tolerable response time. Our analysis shows tolerable response time is achieved when the average of the trivial response time is less than 0.24 seconds for a given service objective. It also shows the optimal utilization consists of three components-%wio, %sys, and %usr. By way of example, the optimal utilizations of a machine running under the UNIX operating system are computed using proposed method.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.27 no.6
• /
• pp.1132-1136
• /
• 1998

The optimum mixing conditions of kochujang(persimmon kochujang) added persimmon puree was optimized by four dimensional response surface methodology. The organoleptic color of persimmon kochujang showed the maximum score in 86.74g red pepper powder, 133.51g persimmon puree and 26.31g salt. The organoleptic aroma persimmon kochujang showed the maximum score in 83.48g red pepper powder, 135.38g persimmon puree and 24.50g salt. The organoleptic taste of persimmon ko chujang showed the maximum score in 85.09g red pepper powder, 133.61g persimmon puree and 25.57g salt. The overall palatability of persimmon kochujang showed the maximum score in 82.99g red pepper powder, 133.10g persimmon puree and 25.47g salt. The optimum mixing conditions for overall orga noleptic properties of persimmon kochujang were 83.00g red pepper powder, 133.00g persimmon puree and 25.00g salt.

• Industrial Engineering and Management Systems
• /
• v.13 no.3
• /
• pp.297-303
• /
• 2014

Stock pre-positioning is one of the most important decisions for preparing the stage of emergency logistics planning. In this paper, a mixed integer model for stock pre-positioning is derived to support an emergency disaster relief response against the event of earthquake. A maximum response time limit, budget availability, multiple item types, and capacity restrictions are considered. In the model, the decision of the distribution centers to cover a disaster area and the amount of supplies to be stocked in each distribution center are simultaneously determined to maximize the total expected relief demand of the disaster areas covered by the existing distribution centers. The proposed model is applied to a real case with 33 disaster areas and 16 distribution centers in Indonesia. Several sensitivity analyses are conducted to estimate the fluctuation on the emergency stock pre-positioning planning by changing the maximum response time and budgets.