• 제어로봇시스템학회:학술대회논문집
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• 1987.10b
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• pp.317-323
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• 1987

A pressure tracking control of hydroforming processes, which is used in the precision forming of. sheet metals, is considered in this paper. The hydroforming of sheet metal is performed between the high-pressure chamber controlled by pressure control valve and the punch moving with constant speed. Since the pressure in the forming chamber is a critical factor to the quality of the product severely. It is important to control the pressure to follow a prescribed pressure trajectory, depending upon the material volume and shape of the parts to be formed. Taking into consideration of the volume chamge of forming chamber during the process and the nonlinearity of the electro-magnetic relief valve, a mathematical formulation of the model describing the dynamic characteristics of this model obtained. Based upon this model a PID controller is designed for the pressure tracking.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.6
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• pp.109-114
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• 2001

Forming pressure of the rupture disc has been analyzed theoretically and verified by experiments. Final shape of the rupture disc after forming process is assumed to be hemi-ellipsoid for small height of the rupture disc. The predicted forming pressures are in good agreement with those by experiment. A new simple model has been proposed to predict the burst pressure of the rupture disc. Experimental results show that the proposed model of burst pressure describes the bursting characteristics of the rupture disc very well.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.4
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• pp.406-414
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• 2004

In Gerotor pump, the pressure pulsations which occur due to the pump geometry result in vibration and noise of pump elements as well as cavitation in hydraulic system when the chambers of gerotor enter the delivery port and leave the suction port. Therefore it is important to study on the pressure pulsations before design and analysis of characteristics in Gerotor pump. In this paper, to reduce the unnecessary pressure pulsations, the port plate of Gerotor pump is designed based on the notch of the vane pumps and the relief grove of the piston pumps. The theoretical analysis of the pressure pulsations is performed in consideration of design parameters of the port plate which include each port positions and groove width and operating conditions which include rotational velocity and delivery pressure.

• Journal of The Korean Dental Society of Anesthesiology
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• v.7 no.2
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• pp.126-130
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• 2007

Sedation is often indicated for the relief of anxiety for outpatient oral surgery. In combination with local anesthesia, it is safe and effective method of treatment. However, it is not always effective in allowing the physician to complete the planned oral surgery procedure. On occasion, a procedure is left unfinished due to patient combativeness and discomfort and hypertension in spite of increase in sedative doses. Episodic increases in blood pressure were most commonly caused by light anesthesia or sedation and by the patient's experience of pain during treatment. Female patient was 42 years old. blood pressure is 150/90 mmHg. Extraction and implant surgery was done under IV sedation. During seadtion, her blood pressure was increased (200/100 mmHg). Surgery was stopped. She was done monitoring blood pressure. The blood pressure was decreased to 130/90 mmHg. Sedation was failed due to significant hypertension. Blood pressure is seldom increased during sedation but we should evaluate the patient's medical history and know guideline for hypertension crisis.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10a
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• pp.1172-1177
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• 1993

Dynamic characteristics of a hydraulic power supply are studied theoretically and computationally. The transfer function between the supply pressure and the load flow is derived considering relief valve dynamics, accumulator dynamics, and flow line dynamics. Frequency responses and time responses are obtained in many conditions using the transfer function and nonlinear mathematical model respectively.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2012.06a
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• pp.201-201
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• 2012

• Journal of Korean Clinical Nursing Research
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• v.17 no.2
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• pp.286-296
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• 2011

Purpose: This research was done to compare the pain relief effects of various nursing interventions, such as cold therapy, attention diversion and 10% Lidocaine spray during arteriovenous fistula needling for patients on hemodialysis, and also to identify and develop more effective nursing interventions for pain relief in these patients. Methods: This research was conducted from October 1, 2010 to January 31, 2011 with 8 hemodialysis patients, who were on regular dialysis (3 times a week) at K University Hospital in Seoul and had an arteriovenous fistula within the past 3 months. Each patient received the three nursing interventions (cold therapy, attention diversion and 10% Lidocaine spray therapy) prior to the arteriovenous fistula needling and applied in turn with the series being repeated 4 times. After each intervention, physiologic indexes, subjective and objective pain were measured at the time of needling. ANOVA was used with SPSS/WIN 12.0 to analyze pain scores and comparison of physiologic indexes (BP, pulse). Results: No significant differences were found for subjective pain (p=.574), objective pain (p=.562) and total pain (p=.506) among the 3 interventions. Systolic blood pressure (p=.689), diastolic blood pressure (p=.969) and pulse (p=.980) also showed no significant difference among the 3 interventions. Conclusion: These 3 interventions are all possible for pain relief during arteriovenous fistula needling for these patients. However, the only interventions that nurses can do independently are cold therapy and attention diversion so we recommend that these nursing interventions be used.

• Journal of Korean Academy of Nursing
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• v.36 no.6
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• pp.992-1001
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• 2006

Purpose: This study was done to provide data for a nursing intervention to alleviate newborn pain clinically by investigating the effect of oral glucose. Methods: Subjects were newborns hospitalized in the nursery. Informed consent was obtained from parents of 60 newborns. A heel stick was carried out for a test on 3 groups; the experimental, placebo, and control group. The Neonatal infant pain scale(NIPS), respiration rate, heart rate, peripheral oxygen partial pressure($SpO_2$), and crying duration were measured to assess pain reaction. All neonatal behaviors were recorded on videotape. Results: There were significant differences in pain behavior during stimulus(F=4.195, p=.020), pain behavior immediately after blood-sampling (F=4.114, p=.021), and pain behavior 3 minutes after that (F=3.630, p=.033). However, there were no significant differences in heart rate, respiration rate, peripheral oxygen partial pressure or crying duration after the heel stick among the groups. Conclusions: Oral administration of glucose before a heel stick caused the reduction of neonatal pain behavior, which means that it has an effect of pain relief.

• The KSFM Journal of Fluid Machinery
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• v.8 no.4 s.31
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• pp.20-26
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• 2005

When the pumps are started or stopped for the operation or tripped due to the power failure, the hydraulic transients occur as a result of the sudden change in velocity. The field tests on the waterhammer were carried out for Pangyo booster pumping station in which had six booster pumps and two in-line pumps with the motor of output 1,700 kW, respectively. The booster pumping station was equipped with the pump control valve as the main surge suppression device, and the surge relief valve as auxiliary one. But the pump control valve had not early controlled in the planned closing mode, the slamming occurred to the valve of which abruptly closed during the large reverse flow. Because the positive pressure wave caused by the pump failure was superposed on the slam surge, the upsurge increased so extremely that the pump control valve was damaged. After the air chambers were additionally installed in the booster pumping station, it was preyed that the water supply system acquire the safety and reliability on the pressure surge.

• Journal of Drive and Control
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• v.15 no.4
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• pp.17-22
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• 2018

Mobile hydraulics require higher energy efficiency, and a simpler as well as robust design, than general industrial hydraulics. The 6/3-way directional control valve is widely used as a mobile hydraulic control valve. However, since the 6/3-way directional control valve is a spool type valve, it is difficult to maintain the load. A counterbalance valve is typically used, to maintain the load, and lift down. However, in an industrial field using a mobile hydraulics device, a pilot controlled check valve may be used to implement holding and lifting operation of the self-weight load, and a relief valve may be used simply to exert back pressure. But no comparative analysis of advantages and disadvantages of each method was revealed. In this study, various methods of holding and unloading load with self-weight in mobile hydraulics are investigated, and compared through simulation using AMESim software. This is experimentally verified by using Festo's mobile hydraulic test rig TP800.