• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.1
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• pp.26-32
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• 2012

Polishing is one of the important methods in manufacturing of Si wafers and in thinning of completed device wafers. This study will report the characteristic of wafer according to processing time, machining speed and pressure which have major influence on the abrasion of Si wafer polishing. It is possible to evaluation of wafer abrasion by load cell and infrared temperature sensor. The characteristic of wafer surface according to processing condition is selected to use a result data that measure a pressure, machining speed, and the processing time. This result is appeared by the characteristic of wafer surface in machining condition. Through that, the study cans evaluation a wafer characteristic in variable machining condition. It is important to obtain optimal condition. Thus the optimum condition selection of ultra precision Si wafer polishing using load cell and infrared temperature sensor. To evaluate each machining factor, use a data through each sensor. That evaluation of abrasion according to variety condition is selected to use a result data that measure a pressure, machining speed, and the processing time. And optimum condition is selected by this result.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.1
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• pp.66-72
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• 2022

The Mooney-Rivlin second order optimal strain energy function derived through uniaxial tensile test and analysis was applied to a gasket to confirm the internal stress and surface pressure generated during compression. The Taguchi method, a statistical technique, was used to design the optimum shape of the gasket, and through characteristic evaluation, the optimum shape of the gasket was obtained when the reference plane (T: 0.15 mm), contact surface (W: 1.00 mm), and curvature (R: 0.30 mm) were used. It was determined that the optimum shape yields a von Mises stress of 4.83 MPa, and the contact pressure stress is 20.14 MPa, which satisfies breakage and sealing requirements. In the future, we plan to manufacture a jig that can measure surface pressure to conduct comparative verification studies between the test results and analysis results.

• Proceedings of the KSME Conference
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• 2001.11b
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• pp.782-787
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• 2001

An optimum thermal design analysis of the combined cycle power plant with triple pressure heat recovery steam generator was performed by the numerical simulation. The optimum design module used in the paper is DNCONF, a function of IMSL Library, which is widly known as a method to search for the local optimum. The objective function to be minimized is the cost of total power plant including the steam turbine power enhancement premium. The result of this paper shows that the cost reduces if the design point of power plant becomes the local optimum, and many calculations at various initial conditions should be carried out to get the value near the global optimum.

• International Journal of Highway Engineering
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• v.13 no.2
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• pp.21-29
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• 2011

Recently, typhoons or heavy rainfalls frequently occurred because of the effect of global warming, which caused serious damage such as landslide of mountain road, debris flow and uplift seepage pressure. Uplift seepage pressure induced on the pavement of mountain roads may cause serious pavement damage. It was known that subsurface drainage method is very effective to reduce uplift seepage pressure. Suitable permeability and stiffness of drainable base is very important to have the effectiveness of subsurface drainage. In this study, optimum particle size distribution of drainable base is investigate to meet the required permeability and bearing capacity of drainable base.

• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.6
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• pp.111-121
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• 2000

Generally, the hydraulic pressures are used for transmitting the force. Therefore, a highly reliable and inexpensive control system has been required for a passenger car. The control-ability of active suspension system is strongly affected by the performance of pressure control valve in the view of dynamic response and energy consumption. In this study, we suggested main design parameters for the optimum design of proportional pressure control valve. The mathematical simulation model was derived from the quarter type model which consisted a valve and hydraulic damper for the purpose of analyzing the valve characteristics. Experiments were performed to confirm the performance of the valve and computations were carried out to ascertain the usefulness of the developed program. The results from computations fairly coincide with those from experiments. This has been achieved by developing the servomechanism valve which comprises the simple combination of a solenoid, a spool valve and a poppet valve. The results from experiments and computations show the development process of optimum proportional pressure control valve in the hydraulics system.

• International Journal of Naval Architecture and Ocean Engineering
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• v.10 no.4
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• pp.439-449
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• 2018

In this paper, multi-objective optimization of a multi-bubble pressure cabin in the underwater glider with Blended-Wing-Body (BWB) is carried out using Kriging and the Non-dominated Sorting Genetic Algorithm (NSGA-II). Two objective functions are considered: buoyancy-weight ratio and internal volume. Multi-bubble pressure cabin has a strong compressive capacity, and makes full use of the fuselage space. Parametric modeling of the multi-bubble pressure cabin structure is automatic generated using UG secondary development. Finite Element Analysis (FEA) is employed to study the structural performance using the commercial software ANSYS. The weight of the primary structure is determined from the volume of the Finite Element Structure (FES). The stress limit is taken into account as the constraint condition. Finally, Technique for Ordering Preferences by Similarity to Ideal Solution (TOPSIS) method is used to find some trade-off optimum design points from all non-dominated optimum design points represented by the Pareto fronts. The best solution is compared with the initial design results to prove the efficiency and applicability of this optimization method.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.15 no.4
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• pp.148-154
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• 2016

A study on the micro particle blasting was conducted to find the optimum conditions of the blasted surface of aluminum 6061. The particle type such as $Al_2O_3$ and SiC, nozzle diameter, pressure, standoff distance and injection time were used as blasting conditions. Statistical method of orthogonal arrays(ANOVA) was used to find optimum conditions of maximum depth and maximum diameter of blasted surface. Particle type, nozzle diameter, and pressure were found to be the main factors of maximum blasted depth and diameter. Maximum blasted diameter was affected by increasing pressure and nozzle diameter but saturated maximum diameter. Maximum blasted depth was affected by pressure and nozzle diameter when aluminum 6061 was blasted with $Al_2O_3$ particle. The value of surface roughness was increased as pressure and nozzle diameter increased when aluminum 6061 was blasted with SiC.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.6
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• pp.10-18
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• 2008

Metal stamping is widely used in the mass-production process of the automobile industry. During the stamping process, air may be trapped between the draw die and the panel. The high pressure of trapped air induces imperfections on the panel surface and creates a situation where an extremely high tonnage of punch is required. To prevent these problems, many air ventilation holes are drilled through the draw die and the punch. The present work has developed a simplified mathematical formulation for computing the pressure of the air pocket based on the ideal gas law and isentropic relation. The pressure of the air pocket was compared to the results by the commercial CFD code, Fluent, and experiments. The present work also used the Bisection method to calculate the optimum cross-sectional area of the air ventilation holes, which did not make the pressure of the air pocket exceed the prescribed maximum value.

• Membrane and Water Treatment
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• v.9 no.5
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• pp.309-315
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• 2018

The applicability of the ultrafiltration process for color removal from dye-containing water has been examined in this study. The optimization of major process variables, such as dye concentration, chitosan concentration and transmembrane pressure on permeate flux and color removal efficiency was investigated. To find the most appropriate results for the experiment, the Box-Wilson experimental design method was employed. The results were correlated by a response function and the coefficients were determined by regression analysis. Permeate flux variation and color removal efficiency determined from the response functions were in good agreement with the experimental results. The optimum conditions of chitosan concentration, dye concentration and pressure were 50 mg/l, 50 mg/l and 3 bars, respectively for the highest permeate flux. On the other hand, optimum conditions for color removal efficiency were determined as 50 mg/l of dye concentration, 50 mg/l of chitosan concentration and 1 bar of pressure.

• Journal of Environmental Science International
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• v.4 no.3
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• pp.259-267
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• 1995

This study was conducted to evaluate the effects of pressure and dissolved oxygen concentration on the activated slut비e and to determine the optimum depth of deep shaft process. Some results from this study were summarized as follows. 1. It is considered that low sludge product in the activated sludge system maintaining high dissolved oxygen concentration is attributed to the increase of endogeneous respiration rate caused by the increase of aerobic zone in the sludge floe. 2. The increase of dissolved oxygen concentration does not affect to the increase of organic removal efficiency greatly and therefore the limiting factor is the substrate transfer into the inner part of floe. 3. The yield coefficient, Y is decreased in proportion to the increase of oxygen concentration. In this study, Y values arre ranged from 0.70 to 0.41 according to the variation of dissolved oxygen concentration from 18.0mg/$\ell$ to 258 mg/$\ell$. 4. The optimum depth of deep shaft process should be determined within the limits of non-toxicity to the microorganism and it is about loom in this study.