• 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.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.33 no.11
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• pp.909-915
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• 2009

In this paper, a study of performance improvement for a centrifugal vertical pump having specific speed of 330 is introduced. The existing model has high efficiency but needs better NPSH required performance. Such that new pump model is designed to obtain larger suction specific speed. 6 design parameters considered to affect pump performance are selected for impeller design. Key design parameters are investigated using by design of experiments and CFD, and impeller inlet diameter is increased to get better suction performance. The amount of inlet diameter increase is determined by using cavitation analysis. The results show that new design model has higher efficiency and better NPSH required performance than the existing model.

• Journal of Korean Neurosurgical Society
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• v.42 no.4
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• pp.346-348
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• 2007

Surgical elevation of the depressed bone is known to be the conventional treatment usually recommended for a simple depressed skull fracture in the adult or pediatric age. The authors introduce, however, a case of depressed skull fracture in an infant which was elevated by means of a cup of breast pump and a suction generator without surgical elevation. In our case, without surgery, a 'cup-shaped' depressed skull fracture in an infant was safely elevated with no neurological signs. This method is considered a simple, effective, safe, and alternative procedure in an infant with simple depressed skull fracture.

• The KSFM Journal of Fluid Machinery
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• v.11 no.1
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• pp.18-25
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• 2008

Recent trends of a centrifugal pump are high speed in rotation and high pressure in head with high efficiency to meet the demands of industries. However, the newly developed pumps make trouble of pressure pulsation in the pumping system by performance instability of the pump. Moreover, cavitation, which is a main obstacle of high rotational speed in the pump, occurring in an impeller gives serious damages to the impeller and casing wall. The purpose of present study is not only to develop a simple method to improve pump performance but also to suppress the occurrence of cavitation in the centrifugal pump by use of J-Groove. J-Groove is a shallow groove installed on the casing wall in the meridional direction. The application of J-Groove to a centrifugal pump with a new type impeller of "semi-closed impeller" has proved its effectiveness as a useful countermeasure of the unstable pump performance and cavitation. The results show that the combination of semi-closed impeller and J-Groove can be applied successfully and improves both the pump performance and suction performance.

• Journal of Environmental Health Sciences
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• v.38 no.4
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• pp.332-339
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• 2012

Objectives: The purpose of this study was to prevent health problems and environmental contamination resulting from inappropriate management of dental wastes and to provide reference data for revision and supplementation of dental clinic waste management guidelines. Methods: From 640 total of dental clinics registered in 16 cities and counties in Gyeongsangnam-do, 100 (60 in Changwon (Masan, Changwon), 29 in Gimhae, and 11 in Jinju) were included in this study. From July 2010 to September 2010, investigators visited the 100 dental clinics and conducted survey interviews using a structured survey questionnaire regarding disposal methods for liquid wastes (suction pump, spittoon container waste, used liquid disinfectants, and X-ray developer), and disposal methods for solid waste (suction pump, spittoon container waste, and general medical waste). Results: All the 100 dental clinics were found to treat liquid waste from suction pumps and spittoon containers in the same manner as general waste water. Nineteen percent of the clinics treated solid waste that was not filtered through the filter of a suction pump as general waste. Fifty or more percent of the clinics treated solid waste in spittoon containers as general waste. Seventy percent of the clinics used disinfectant solution, although most of them treated used disinfectants in the same manner as general waste water. Some clinics treated used X-ray developer and X-ray fixer in the same manner as general waste water. In most of the clinics, used drapes were washed within the clinic. Conclusions: It was found that waste water and dental wastes at some dental clinics were treated in inappropriately. Thus, in conclusion, the development of guidelines regarding proper management of liquid and solid dental waste at dental clinics is required, and hygiene and environmental training for workers at dental clinics is necessary.

• Journal of KSNVE
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• v.10 no.3
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• pp.500-507
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• 2000

Dynamic forces due to mechanical and hydraulic related causes are always exerted on operating turbomachinery such as centrifugal pumps. To ensure the safety and the reliability of the pump. the magnitudes of the vibration must be kept within an acceptable limit. The focus of this paper is on the identification of the vibration behavior and the quantitative analysis of the hydraulic excitation forces. As the structure becomes more complex finite element analysis is essential to accurately predict the vibration characteristics and the excitation forces, This paper presents an experimental and analytical technique to find and solve to vibration problems in double volute double suction centrifugal pump. Measured vibration data due to the dynamic forces are presented and individual causes are identified, finally excitation forces of the pump are inversely estimated at each frequency on operating conditions.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.4
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• pp.233-239
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• 2000

Investigation results are presented fur the shaft end displacements due to the elastic deformation of the casing and support in double suction centrifugal pump. Suction and discharge nozzles of the pump are subject to external piping loads and, in API 610, maximum values of their components are specified. This means that each nozzle can be subject to various combinations of loading conditions. Considering upper and lower criteria of each load, we must perform for the 4,096 load cases, and assign the direction and range of the loads. So, this paper develops an efficient procedure(Compliance Coefficient Method) to calculate the shaft end displacements(＠ coupling) to determine whether satisfying the pump's standard. Also, we analyzed the effects of the casing and support thickness on shaft end displacements.

• The KSFM Journal of Fluid Machinery
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• v.12 no.6
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• pp.7-12
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• 2009

This paper presents a numerical study on the design of side-suction inlet geometry which is used for multi stage centrifugal pumps or inline centrifugal pumps. In order to achieve an optimum inlet geometry and to explain the interactions between the different geometric configurations, the three dimensional computational fluid dynamics and the design of experiment methods have been applied. Geometric design variables describing the cross sectional area distribution through the inlet were selected. The objective functions are defined as the non-uniformity of the velocity distribution at the passage exit which is just in front of the impeller eyes. From the 2k factorial design results, the most important design variable was found and the performance of the side suction inlet was improved compared to the base line shape.

• Journal of the Korean Geotechnical Society
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• v.19 no.5
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• pp.155-162
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• 2003

The soil-water characteristic curve (SWCC) represents the essential constitutive relationship for solving various problems in unsaturated soil mechanics. A reliable and convenient experimental method is needed for the determination of the SWCC in engineering applications. This study introduces and proves that the suction-saturation experimental measurement based on the flow pump technique is a convenient and accurate method for obtaining the SWCC. The flow pump technique provides complete control over the test conditions and is capable of detecting all the important elements of the SWCC. In particular, it is capable of defining continuous drying and wetting curves, the moment of air occlusion, and the hysteretic behavior of unsaturated soils. Not only the optimal testing procedure but also the analysis technique for the flow pump technique has been established in this study. Especially, the method of the suction drop measurement was developed to measure the SWCC. This method is a convenient and time saving method without losing accuracy.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.297-298
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• 2012