• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.12 s.243
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• pp.1645-1652
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• 2005

Pick-and-place systems using suction cups have been being widely used and continuously developed in production automation. There are, however, some drawbacks in constructing such systems. One of them is that it generates high level noise due to air compressors. And the system must have complex constitutions of mechanical component such as air compressors, air tubes, air valves, etc. Moreover, it needs continuous air supply to maintain vacuum in suction cups. If there is a failure in any suction cup, the total suction system may fail owing to air leakage. To overcome these drawbacks, we propose PMS (Permanent Magnet Suction) mechanism which has permanent magnets for vacuuming suction cups with no air compressor. The basic concept of PMS mechanism is to rotate permanent magnets with fixed angle. Simple rotation of permanent magnets changes the direction of the magnetic force applied at the suction cups. Since each suction cup has no direct connection with any of the others, the air leakage at one suction cup is not critical. The proposed suction mechanism was designed and fabricated. With some experiments, the feasibility and performance of the PMS mechanism was shown. The strong points of the PMS mechanism are in its simple structure, generating low noise, high energy efficiency, and no need of continuous energy supply.

• Journal of Power System Engineering
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• v.21 no.2
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• pp.89-94
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• 2017

Pneumatic systems are widely applied in various industry because it have a many advantage(low cost, high safety, etc.). Air compressors supply the working fluid to the pneumatic systems and consume a lot of electrical energy at the manufacturing site. The one of the suggested idea is to reduce the energy consumption by reducing the suction temperature of the air compressor and increasing the discharge flow rate. In this paper, the discharge flow rate and air power of the positive displacement type air compressor is simulated by changing the temperature of suction air and the relationship between the suction air temperature and the performance variation of the air compressor is analyzed. As a result, we know that as the suction temperature of air is lowered, the discharge mass flow-rate is increased, but the specific enthalpy is reduced rather than increased, which means that the power of the discharged air is not greatly increased even if lower the suction air temperature.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.1429-1436
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• 2000

Suction muffler is one of the important component of a compressor for low noise level and high efficiency. The suction muffler which has the complicated flow path gives the higher transmission loss of sound, but lower efficiency of compressor results from the superheating effect and flow loss in suction flow path. It is shown that the computational analysis of fluid dynamics are very popular methods for designing of high performance and low noise suction muffler. To reduce the thermodynamic and flow loss in suction process, the flow path of suction muffler was estimated by FVM(Finite Volume Method) and verified by experiments. And to enlarge the transmission loss of sound, the acoustic properties inside the suction muffler was analyzed by FEM(Finite Element Method) and experiments. The smart muffler which gives a good efficiency and low noise character was developed by using those methods, and the effect was evaluated in compressor by experiment.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2632-2637
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• 2007

Rotary performance and flow resistance induced by each element in suction nozzle of a vacuum cleaner with a double-blade rotary fan are investigated numerically and its relation with flow-induced noise and rotary performance is examined. Flow resistance and vorticity in suction nozzle are calculated and it is found that they are closely related with flow-induced noise. Gap between double blades, adoption of cross-flow fan, enlargement of flow inlet area, and optimization of blade number are tested for noise reduction. Finally, the effects of each method are verified experimentally. It is found that several combinations of the proposed methods can be adopted for noise reduction although the degree of reduction is not much.

• Journal of computational fluids engineering
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• v.8 no.3
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• pp.32-40
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• 2003

CFD analyses of the three-dimensional turbulent flow in the impeller and diffuser of an axial flow pump including suction and discharge parts are presented and compared with experimental data. The purpose of the current study is to validate the CFD method for the performance analysis of the main coolant pump for SMART and to investigate the effect of suction and discharge shapes on the pump performance. To generate a performance curve, not only the design point but also the off-design points were computed. The results were compared with available experimental data in terms of head generated. At the design point, the analysis accurately predicts the experimental head value. In the range of the higher flow rates, the results are also in very good agreement with the experimental data, in magnitude but also in terms of slope of variation. For lower flow rates, the results shows that the analysis considering the suction and discharge well describe the typical S-shape performance curve of the axial pump.

• The KSFM Journal of Fluid Machinery
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• v.18 no.1
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• pp.11-19
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• 2015

Recently, the cross flow turbines attract more attention for their good performance over a large operating regime at off design point. This study employs a very low head cross flow turbine, which has open inlet duct and has barely been studied before, to investigate the performance of the cross flow turbine with air suction from the rear part of the runner. Unlike conventional cross flow turbines, a draft tube is attached to the outlet of runner to improve the turbine performance. Water level and pressure in the draft tube are monitored to investigate the influence of air suction. Torque at local blade passage of three parts of runner is examined in detail under the conditions of different air suction. Consequently, it is found that with proper air suction in the runner chamber, the water level in the draft tube gradually drops to Stage 2 of the runner and the efficiency of the turbine can be raised by 10%. Overall, the effect of air-layer on the performance of the turbine is considerable.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.455-456
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• 2011

• The Journal of Korean Academic Society of Nursing Education
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• v.23 no.3
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• pp.330-340
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• 2017

Purpose: This study was conducted to explore the relationship between simulation-based clinical judgment and performance ability for tracheal suction in nursing students. Methods: With a convenience sampling, 207 nursing students participated in this descriptive study. Lasater clinical judgment rubric was used for self-reported clinical judgment in addition to observe the skill of tracheal suction using a checklist. Data were analyzed by descriptive statistics, t-test and Pearson's correlation coefficients using the SPSS/WIN 22. Results: A scenario with pneumonia patient was developed to observe the skill of tracheal suction during simulation-based practices. Then self-reported clinical judgment was scored. The mean score of total sum of clinical judgment, total mean of clinical judgment, and performance skill were $36.44{\pm}4.82$, $13.44{\pm}1.71$, and $42.32{\pm}5.05$, respectively. Statistically, students having good skills in suction showed significant differences in clinical judgment of interpreting (p=.031) compared to students having fair skills. Conclusion: The results of this study show that a structured debriefing method utilizing Lasater clinical judgment rubric is helpful. Also, simulation-based practice related to adult nursing in the respiratory system was useful for increasing the core basic skills among nursing students.

• Journal of Home Health Care Nursing
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• v.22 no.1
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• pp.88-97
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• 2015

Purpose: This study was conducted to identify the effects of a suction care self video-based debriefing-assisted learning in the fundamentals of nursing practice for nursing students on clinical performance, self-efficacy and problem-solving process. Methods: A nonequivalent control group non-synchronized design study was used and included 97 junior nursing students at P University as participants, 48 of whom were assigned to the experimental group, and 49 of whom were assigned to the control group. The outcome measurements were clinical performance for suction care, self-efficacy, and the problem-solving process. Results: The scores of clinical performance were 23.75 in the experimental group who used the materials and 21.55 in the control group, and the difference was statistically significant (p<.000). Self-efficacy was 4.30 in the experimental group and 4.18 in the control group, which was a statistically significant difference (p=.000), and the pre-to-post differences of self-efficacy was statistically significant as well (p<.001). However, there were no significant differences in the pre-to-post differences of the problem-solving process (p<.802). Conclusions: Self video-based debriefing-assisted learning may be more effective in enhancing clinical performance and self-efficacy than that of conventional practice. Whether self-efficacy will contribute to enhanced learning motivation for nursing students needs further examination.

• International Journal of Fluid Machinery and Systems
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• v.4 no.1
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• pp.191-198
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• 2011

Based on the consideration that the cavitation would affect the operation stability of miniature pumps, the 3-D turbulent cavitating flow in a test pump was simulated by using a mixed cavitation model and k-${\omega}$ SST turbulence model. In order to investigate the influence of inlet geometry parameters on the cavitation performance of the miniature pump, two more impellers are designed for comparison. Based on the results, the following conclusions are drawn: 1) Cavitation performance of the double suction shaft-less miniature pump having different impeller is equivalent to the centrifugal pump having ordinary size, though the flow passage at impeller inlet is small; 2) The miniature pump having radial impeller can produce much higher pump head, but lower cavitation performance than that having the impeller based on the conventional design method; 3) It is believed that by applying the double suction design, the miniature pump achieved relatively uniform flow pattern upstream the impeller inlet, which is favorable for improving cavitation performance.