• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• v.y2005m4
• /
• pp.88-91
• /
• 2005

The combustion characteristics of high burning HTPB/AP solid propellants have been investigated by means of a closed bomb method of interval volume of 200 co and 700 cc at pressures from 1000 to 30,000 psi. The burning rate data measured by closed bomb are in good agreement with strand burner test results at pressure from 1000 to 5000 psi using disc sample of 1 mm thickness. The burning rate dat by using 200 cc closed bomb are in general agreement with that of 700 cc closed bomb. At pressure between $5,000\sim7,000$ psi, a market increase in pressure dependence of the linear burning rate occurs for HTPB/AP propellant.

• Imaging Science in Dentistry
• /
• v.47 no.4
• /
• pp.233-239
• /
• 2017

Purpose: This study was performed to quantify the repeat rate of imaging acquisitions based on different clinical examinations, and to assess the prevalence of error types in intraoral bitewing and periapical imaging using a digital complementary metal-oxide-semiconductor(CMOS) intraoral sensor. Materials and Methods: A total of 8,030 intraoral images were retrospectively collected from 3 groups of undergraduate clinical dental students. The type of examination, stage of the procedure, and reasons for repetition were analysed and recorded. The repeat rate was calculated as the total number of repeated images divided by the total number of examinations. The weighted Cohen's kappa for inter- and intra-observer agreement was used after calibration and prior to image analysis. Results: The overall repeat rate on intraoral periapical images was 34.4%. A total of 1,978 repeated periapical images were from endodontic assessment, which included working length estimation (WLE), trial gutta-percha (tGP), obturation, and removal of gutta-percha (rGP). In the endodontic imaging, the highest repeat rate was from WLE (51.9%) followed by tGP (48.5%), obturation (42.2%), and rGP (35.6%). In bitewing images, the repeat rate was 15.1% and poor angulation was identified as the most common cause of error. A substantial level of intra- and inter-observer agreement was achieved. Conclusion: The repeat rates in this study were relatively high, especially for certain clinical procedures, warranting training in optimization techniques and radiation protection. Repeat analysis should be performed from time to time to enhance quality assurance and hence deliver high-quality health services to patients

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2008.03a
• /
• pp.775-780
• /
• 2008

This paper reports on the internal flow of a centrifugal mini pump working at the low flow rate operating conditions. The RNG $\kappa-\varepsilon$ turbulence model was employed to simulate the three-dimensional turbulent flow in the pump. To examine and certify the simulation results, a transparent acrylic centrifugal mini pump model which is suitable for PIV measurement has been developed. The tongue region and the passages region between blades were investigated using PIV. In order to eliminate the effect of refraction on the area closed to the wall and increase the measurement accuracy, the fluorescent particles were scatted into the working fluid with the tracing particles. It is found from the calculation and PIV measurement results that there is a large area of recirculation flow near the tongue at low flow rate operating conditions. The computationally predicted water head using the $\kappa-\varepsilon$ turbulence model at low flow rate operating conditions are in very good agreement with the experimentally measured water head and the mean velocity distributions at investigation area obtained by PIV and calculation showed a satisfactory agreement as well. Meanwhile, the results of PIV measurements show that the flow status in one passage is different to another. And for capturing the internal flow detail information, the $\kappa-\varepsilon$ turbulence model is not very suitable.

• Journal of the Korean Society of Combustion
• /
• v.19 no.4
• /
• pp.49-55
• /
• 2014

Design criterion for the size of micro Pt-catalytic combustor is investigated in terms of heat release rate. One-dimensional plug flow model is applied to determine the surface reaction constants using the experimental data at stoichiometric butane-air mixture. With these reaction constants, the mass fraction of butane and heat release rate predicted by the plug flow model are in good agreement with the experimental data at the combustor exit. The relationship between the size of micro catalytic combustor and mixture flowrate is introduced in the form of product of two terms-the effect of fuel conversion efficiency, and the effect of chemical reaction rate and mass transfer rate.

• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.17 no.3
• /
• pp.8-13
• /
• 2008

The paper proposes a model-based measurement of unsteady flow rate by using distributed parameter pipeline model and the measured pressure values at two distant points along the pipeline. The distributed parameter model of hydraulic pipeline is applied with consideration of frequency dependent viscosity friction and unsteady velocity distribution at a cross section of a pipeline. By using the self-diagnostics functions of the measurement method, the validity is investigated by comparison with the measured and estimated pressure and flow rate wave forms at the halfway section on the pipeline. The results show good agreement between the estimated flow rate wave forms and theoretical those under unsteady laminar flow conditions. The method proposed here is useful in estimating unsteady flow rate through an arbitrary cross section in hydraulic pipeline and components without installing an instantaneous flowmeter.

• Proceedings of the SAREK Conference
• /
• 2008.06a
• /
• pp.1231-1236
• /
• 2008

The flow and heat transfer performance were measured at high temperatures in CFB heat exchanger with multiple risers and downcomers. The theoretical model for predicting heat exchanger performance was developed in this study. The model predictions were compared with the measured heat transfer rates to show relatively good agreement. The maximum gas cooling rate was $20,300^{\circ}C/sec$, and the dioxin reduction rate was 68%.

• Proceedings of the KIEE Conference
• /
• 2007.07a
• /
• pp.1053-1054
• /
• 2007

This paper represents technique of optimum efficiency calculation for condenser run type single phase induction motor considering utilization rate. The material cost and loss expense are major factor of proposed algorithm. The simulation results are compared with experimental ones. And they are agreement with each other.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.22 no.9
• /
• pp.1271-1276
• /
• 2018

The CPTPP(Comprehensive and Progressive Agreement for Trans-Pacific Partnership) is a large-scale free trade agreement(FTA) in the Asia-Pacific region involving 11 remaining countries(Japan, Australia, New Zealand, Canada, Mexico, Chile, Peru, Singapore, Vietnam, Malaysia and Brunei) since the withdrawal of the US TPP in January 2017, Although the economic size is smaller than the TPP, the CPTPP has 12.9% of the world GDP and 14.9% of the trade volume, meaning that another mega FTA is born. Local economic experts believe that Vietnam's stable economic growth rate and the CPTPP agreement will have a positive impact on Vietnam's stock market and M&A market in 2018. The experts usually expect it will be come into force in 2018 and not later than 2019. The CPTPP is also very likely to enter into force in 2019 with the aggressive attitude of the member countries, simplifying the entry into force of the agreement.

• Korea Journal of Hospital Management
• /
• v.13 no.1
• /
• pp.42-64
• /
• 2008

This study was conducted to evaluate the quality in medical records by analyzing its completeness through setting up the level of record on the patient's past history and through examining the actual medial records. Targeting the information on the patient's past history in interns' records, residents' records and nurses' records toward 403 inpatients who were admitted first in 2004 at an university hospital due to stomach cancer. We analyzed whether the charts were recorded or not, recording level, the satisfaction with the expectant level of the records in the hospital targeted for a research and the level of agreement. The results were as follows; first, as for the rate of recording those each items, they were high in the chief complaint & present illness and the past illness history. Depending on the group of recorders, the recording rate showed big difference by items. Second, as a result of measuring the level after dividing the recording level of items for the patient's past history from Level 1 to Level 4 by each item, the admission history, the past illness history, and the family history were about Level 3, and the smoking history, the medication history, the chief complaint & present illness, the drinking history and allergy were about Level 2. In the admission department, it was excellent in the interns' records for the medical department. Third, as a result of its satisfactory level by comparing the expect level of a record and the actual record by item in information on the patient's past history, which was expected by the medical-record committee members of the hospital targeted for a study. And forth, we analyzed the level of agreement with Kappa score in the level of 'Yes' or 'None' related to the corresponding matter in Level 1, in terms of information on the past history in the intern's record, the resident's record, and the nurse's record. The level of agreement in the resident's record & the nurse's record, and in the intern's record & the resident's record was from "excellent" to "a little good". There were differences in the level of completeness and in reliability for the information on the past history by the recorder group or by the admission department. The encounter process that was performed by the admission department or the recorder group, indicated the result that was directly reflected on the quality of medical records, thus it was required further study about the medical record documentation process and quality of care. The items that showed the high recording rate quantitatively were rather low, consequently we'd should develop the tool for the qualitative inspection and evaluate the medical records further. And the items were needed to be detailed in the record level were rather low, and hence there needed to be a documentation guideline and education by the clinical departments.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.15 no.2
• /
• pp.537-543
• /
• 1991

In this study, the strain rate effects are considered in the formulation by introducing the constitutive equation of the strain rate sensitive materials and rigid-viscoplastic finite element program is developed for axisymmtric extrusion. The effect of strain rate sensitivity on the flow characteristics and forming pressure are investigated and the experiments are carried out for extrusion with pure lead specimens. The theoretically predicted forming pressure showed reasonably good agreement with the experimental values.