• Transactions of Materials Processing
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• v.10 no.2
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• pp.115-122
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• 2001

It is well known, for many years, that deep drawability can be improved by applying variable blank holding force. To apply variable blank holding force during cup drawing, we set up cushion pressure control system on the hydraulic press, and the pressure control system is often called NC(Numerically Controlled) cushion system. A cushion pressure control experiment was carried out using the NC cushion and it was shown that the proposed system produced good performance. The comparison of drawability of square cups with and without NC cushion showed that the drawability could be greatly improved when S-shaped pressure curve was applied. This paper includes design details of the NC cushion system and experimental analysis of drawability with NC cushion system.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.32 no.2
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• pp.132-147
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• 1996

The optimal design of floating type fisheries facilities in the open sea is demanded considering with the severe hydrodynamic forces on floating body, mooring tension and holding force of anchor. For conserving the facilities in most effective state, design and selection of anchor system is one of the most important fundamental subject. To enhance the design procedure of anchor system the holding forces of anchor are investigated by the hydraulic model test and are compared with the typical conventional results for various anchors. Applicability of previous estimation methods of holding force are checked and holding mechanism of anchor is discussed. Using the results a new computational concept of holding force is suggested considering mainly the effects of passive soil pressure (resistance), steady soil pressure, and surface friction etc. The new estimation method is proved as a feasible one by comparing the results of hydraulic model experiments. Applicability of various anchors to the anchor system on open sea fisheries structures is comprehensively reviewed using the present model tests and previous study results in the viewpoint of economy, construction and stability etc. Using the results, fundamental anchoring system design procedures are suggested to apply huge marine ranching complex with increase of the holding capacity of anchor under the optimum cost.

• Journal of the Korean Institute of Gas
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• v.17 no.6
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• pp.1-7
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• 2013

Internal pressure variation analysis and actual holding time test on ISO LNG tank containers which were made in Korea for the first time according to the special notification of ISO tank container manufacture have been conducted during the transport demonstration projects of the tank containers by tractor, train and ship. The internal pressure of the LNG tank container increased rapidly after LNG filling and dropped during moving the container. However, it was stabilized as time passed and followed the liquid-vapor equilibrium graph. In addition, actual holding time of the tank container was more than 20 days which was satisfied with the special notification of LNG tank container manufacture.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.4
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• pp.414-419
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• 2016

A study of a precision test according to the control method of an injection molding machine was carried out. The effects of the screw stroke, holding pressure, melt temperature on both the hydraulic and electric injection molding machine were examined. In addition, hypothesis testing was performed to determine the deviation of the data obtained in the experiments. The conclusions obtained in this study were as follows. Significant deviations in the screw stroke, melt temperature and holding pressure occurred in that order. The hydraulic type showed significantly more variation between the products compared to the electric type. In addition, using a mini tab from the statistics program, a hypothesis was proposed and the P value of the injection stroke, holding pressure, melting temperature injection stroke and melting temperature had adopted a null hypothesis ($H_0$). The holding pressure, which showed mutual differences, adopted an alternative hypothesis ($H_1$).

• International Journal of Fluid Machinery and Systems
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• v.3 no.4
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• pp.315-323
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• 2010

This work investigates the influence of water compressibility on pressure pulsations induced by rotor-stator interaction (RSI) in hydraulic machinery, using the commercial CFD solver ANSYS-CFX. A pipe flow example with harmonic velocity excitation at the inlet plane is simulated using different grid densities and time step sizes. Results are compared with a validated code for hydraulic networks (SIMSEN). Subsequently, the solution procedure is applied to a simplified 2.5-dimensional pump-turbine configuration in prototype with different speeds of sound as well as in model scale with an adapted speed of sound. Pressure fluctuations are compared with numerical and experimental data based on prototype scale. The good agreement indicates that the scaling of acoustic effects with an adapted speed of sound works well. With respect to pressure fluctuation amplitudes along the centerline of runner channels, incompressible solutions exhibit a linear decrease while compressible solutions exhibit sinusoidal distributions with maximum values at half the channel length, coinciding with analytical solutions of one-dimensional acoustics. Furthermore, in compressible simulation the amplification of pressure fluctuations is observed from the inlet of stay vane channels to the spiral case wall. Finally, the procedure is applied to a three-dimensional pump configuration in model scale with adapted speed of sound. Normalized Pressure fluctuations are compared with results from prototype measurements. Compared to incompressible computations, compressible simulations provide similar pressure fluctuations in vaneless space, but pressure fluctuations in spiral case and penstock may be much higher.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2000.10a
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• pp.120-123
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• 2000

It is well known, for many years, that deep drawability can be improved by applying variable blank holding force. To apply variable blank holding force during cup during, we set up pressure controlling system on experimental hydraulic press, and the pressure control system is often called NC(Numerically Controlled) cushion system Using the NC cushion system we compared the drawability of square steel cups with NC cushion and that with conventional cushion. The results show drawability is greatly improved when the pressure control curve is designed in a S-shaped curve. This paper includes design details of the NC cushion system and experimental analysis of drawability with experimental NC cushion system.

• Transactions of Materials Processing
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• v.10 no.5
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• pp.425-432
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• 2001

In order to investigate the influences of process parameters on the shape of lead frame, experimental study has been carried out. In the experiment, dimensional accuracy of the die sets, measurement accuracy has been managed carefully enough to simulate actual lead frame blanking process. With the blanking of square-shaped specimen, the effects of clearance, strip holding pressure and bridge width on the shape of blanked profile have been investigated. Experimental results show that the burnish ratio is increased as the clearance decreases. the strip holding pressure increases, and bridge width increases. Although the results seems to be similar to the ordinary blanking, the lead frame blanking shows a subtle different characteristics to the ordinary blanking due to the narrow bridge width.

• Journal of East-West Nursing Research
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• v.4 no.1
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• pp.7-20
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• 1999

Operation usually brings about psychological stress as well as physical stress to the patient and it greatly influences the maintenance of the homeostasis. Until now, most of the nursing research concerning the anxiety of the patient undergoing an operation has been done while the patient was under general anesthesia. Under local anesthesia, the anxiety of the patient who undergone operation is short. However, there is much demand of the operational nurses to mediate between the patient who is undergoing operation when fully conscious, as they are aware of the patient's anxiety and to decrease the patient's anxiety of this local anesthesia. Therefore, this research tries to verify the effects of the Hand-holding program on the anxiety of the operational patient undergoing local anesthesia and affirms the role of the nursing intervention. As an unequivalent control group non-synchronized designs, this research selects out 20 control groups and 21 experimental groups at random who have received cataract operation while under local anesthesia and after implementing the Hand-holding program to the experimental groups while undergoing the operation, the effect of the experiment was observed. By observing the Epinephrine, Cortisol, blood pressure, and pulse for the physical indexes before and after the enforcement of the hand-holding, and using the measurement of Speilberger(1972) for the psychological indicators for the anxiety of the patient before and after hand-holding, the results were analyzed through SAS program. As a results, intervention of hand-holding had a remarkable effect to decrease the anxiety felt by the patient and the diastolic blood pressure also was effectively decreased. On the other hand, through the decrease of the systolic blood pressure was also observed, it was not statistically significant. In the Epinephrine and Cortisol indicators, the intervention of hand-holding was revealed to have an insignificant effect. The Hand-holding was revealed to have an indicators, the intervention of Hand-holding was revealed to have an insignificant effect. The Hand-holding program may be said to have an effect which decreases the psychological anxiety of the patient undergoing local anesthesia.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.90-95
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• 2007

In order to investigate the optimum condition of the autofrettage process for the diesel engine injection pipe, different values of autofrettage pressure, pressure rising time, pressure holding time, and repetition of autofrettage process were applied. Autofrettage was preformed by applying the hydrostatic internal pressures of 603 MPa, 535 MPa, 500 MPa on the fuel injection pipe, corresponding to theoretically 50%, 30%, and 20% overstrain levels, respectively. The autofrettage residual stresses in the injection pipe were experimentally determined by using X-ray diffractometer. As the overstrain level increased, the magnitude of compressive residual stress at the bore increased. It was found that the rising time to reach the autofrettage pressure, holding time at the autofrettage pressure, and repeating application of the autofrettage pressure on the pipe had no significant influence on the residual stress distributions.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.04a
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• pp.70-75
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• 2004

In this study, the pattern of lens aberration was studied at different injection molding conditions such as injection speed, holding pressure, holding pressure time, mold temperature and cylinder temperature and, then, the results were analyzed with a laser interferometer. It was demonstrated that optimal condition of lens aberration could be achieved by adjustment of injection molding conditions.