• Journal of the Korea Organic Resources Recycling Association
• /
• v.23 no.4
• /
• pp.11-20
• /
• 2015

In the present work, a basic study on the in-situ biogenic methane generation from low grade coal bed was conducted. Lignite from Indonesia was used as a sample feedstock. A series of BMP (Biochemical Methane Potential) tests were carried out under the different experimental conditions. Although nutrients and anaerobic digester sludge were added to the coal, the produced amount of methane was limited. Both temperature control and particle size reduction showed little effect on the increase of methane potential. When rice straw was added to lignite as an external carbon source, methane yield of 94.4~110.4 mL/g VS was obtained after 60 days of BMP test. The calorific value of lignite after BMP test decreased (4.5~12.1 %) as increasing the content of rice straw (12.5~50 wt % of lignite), implying that anaerobic digestion of rice straw led to partial degradation of lignite. Therefore, rice straw could be used as an external carbon source for the start-up of in-situ biogas generation from low grade coal bed.

• Quality Improvement in Health Care
• /
• v.7 no.2
• /
• pp.156-167
• /
• 2000

Background: Emphasis in healthcare during the 1990s has been to provide both optimal wellness and function with quality in a Cost-effective manner. Critical pathway was developed to meet the need to guide clients along the continunm of care and to achieve continuity of care. The purpose of this study is to review and analyze articles related to the critical pathway that had developed and applied in Korea and abroad from 1995 to 1999. Methods: Total 39 studies were analyzed in terms of group of application, need of development, horizontal axis: time frame, vertical axis : items of care, task force team, identification of preliminary critical pathway, validation of preliminary critical pathway, types of final critical pathway, a person who coordinates and effects on critical pathway. Results: In the aspect of group of application, there were various diseases in the overseas than in Korea. In domestic and overseas, the horizontal axis included mainly the time from the start of hospitalization to discharge and vertical axis of the critical pathway included commonly the following nine items : tests, diet, medications, consultations, activity, assessments, treatments, education, discharge planning. Preliminary critical pathway was mainly drawn up through chart review in both. Types of final critical pathway were mostly for medical team use in Korea and were for medical team and patient use in abroad. A person who coordinates critical pathway was mostly nurse in abroad. There was positive effects on critical pathway in both. Conclusion: Staff education and information about critical pathway are needed to use it effectively.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.12 no.2
• /
• pp.74-80
• /
• 2008

The feasibility study into the development of turbine spinners, which start up the turbo-pump, has been carried out and the design requirements and parameters ranges have been presented. Turbine spinners use the solid propellant as such composite propellant based AN compound with high energy plasticizers, coolants, and phase stabilizer which relieves a sensible volume change due to the phase transformation of AN near room temperature. Propellants which have a homing rate of $0.2{\sim}0.3\;mm/s$ and pressure exponent ranged from 0.3 to 0.6, showed stable burn-out in the standard motor tests. Both the magnitude of ignition energy and its thermal transfer mechanism have been proved to have a tangible effect on the ignition of the pyre starter, and the results of this study showed that a flame temperature of 1400K would be quite adequate to get a stable ignition for the AN composite propellant.

• Proceedings of the SAREK Conference
• /
• 2008.11a
• /
• pp.125-130
• /
• 2008

The main components of the KSTAR helium refrigeration system (HRS) can be classified into the warm compression system (WCS) and the cryogenic devices according to the operating temperature levels. The WCS itself consists of the compressor station (C/S) and the oil removal system (ORS). The process helium is compressed from 1 bar to 22 bar maximum in the C/S and downstream, the ORS removes the oil mixed in the helium to less than 10 ppbw as per the operation criteria of the cryogenic devices of the KSTAR HRS. After the installation, the pre-commissioning and commissioning activities were started on July, 2007. Before the start-up of the C/S, vibration measurement and the skid reinforcement jobs were performed for stable operation of the C/S. The results of the WCS performance tests met the requirements of the KSTAR HRS but satisfied the vibration level criteria only at the compressors' full load condition.

• Journal of the Korean Society for Railway
• /
• v.16 no.3
• /
• pp.189-195
• /
• 2013

Recent trains have broadband train communication networks to improve train operation safety and to provide passengers with multimedia services. Compared to glass optical fiber, plastic optical fiber (POF) has a large diameter; it also provides the good durability and maintainability necessary to railway applications. This paper suggests an All-IP broadband train communication network that connects all devices in the train through a POF interface. Performance tests according to Korean railroad standards shows that this POF interface is usable in the range of vibration and temperature conditions encountered in trains. A dedicated Layer-2 switch with the POF interface is developed for the construction of the All-IP train communication network. A prototype 1Gbps train communication network was set up in a trial-run of train on a metro line using the developed Layer-2 switch and POF. On-track tests indicated the feasibility of the POF train communication network. POF has an additional advantage of economic feasibility, and it is expected to start a trend toward broadband train communication networks using POF.

• Journal of Korean Ophthalmic Optics Society
• /
• v.20 no.4
• /
• pp.519-526
• /
• 2015

Purpose: To evaluate the changes of OSI value according to tear-film instability measured serially by OQAS(Optical Quality Analysis System, Visiometrics, Spain) every seconds. The presented study analyzed the relationship of the OQAS parameter with the results of the tear-film break-up time, Schirmer test, and the McMonies score. Methods: 147 eyes of 82 subjects were randomly selected from university students (age: $21.51{\pm}3.97$, male 45, female 37). Subjects were measured tear-film break-up time, Schirmer test, McMonies score and once every second for 15 seconds after blinking by continuous measurements from OQAS system. Results: The normal eye groups presented OSI values of $2.13{\pm}1.16$ while the dry eye groups had OSI values of $3.76{\pm}1.42$. Therefore, a significant difference between the normal eye group and dry eye group was discovered (p<0.05). In addition, the OSI value of all subjects increased over time. The OSI value, which was measured every second after blinking occurred, significantly increased between 6 seconds and 7 seconds after the start of the measurement (p<0.05). OSI cut off of 30% (sec.) showed a greater correlation; TBUT (r = 0.855, p = 0.000), McMonies test (r = -0.351, p = 0.003), Schirmer (r = 0.316, p = 0.012). Conclusions: Continuous measurement of OQAS showed a high correlation with the value of the existing dry eye tests. Therefore, Analysis of OSI values by utilization of OQAS could be useful in objectively evaluation of tear film in patients.

• The Korean Journal of Financial Management
• /
• v.21 no.2
• /
• pp.125-151
• /
• 2004

This study tests the price discovery from US Treasury bond markets to Korean bond markets using the daily returns of Korean bond data (CD, 3-year T-note, 5-year T-note, 5-year corporate note) and US treasury bond markets (3-month T-bill, 5-year T-note 10-year T-bond) from July 1, 1998 to December 31, 2003. For further research, we divide full data into two sub-samples on the basis of the start-up of bond valuation system in Korean bond market July 1, 2000, employing uni-variate AR(1)-GARCH(1,1)-M model. The main results are as follows. First the volatility spillover effects from US Treasury bond markets (3-month T-bill, 5-year T-note, 10-year T-bond) to Korean Treasury and Corporate bond markets (CD, 3-year T-note, 5-year T-note, 5-year corporate note) are significantly found at 1% confidence level. Second, the price discovery function from US bond markets to Korean bond markets in the sub-data of the pre-bond valuation system exists much stronger and more persistent than those of the post-bond valuation system. In particular, the role of 10-year T-bond compared with 3-month T-bill and 5-year T-note is outstanding. We imply these findings result from the international capital market integration which is accelerated by the broad opening of Korean capital market after 1997 Korean currency crisis and the development of telecommunication skill. In addition, these results are meaningful for bond investors who are in charge of capital asset pricing valuation, risk management, and international portfolio management.

• Bulletin of the Korean Chemical Society
• /
• v.32 no.9
• /
• pp.3295-3305
• /
• 2011

Thermal behavior of poly (methyl methacrylate) was analyzed in the presence of tin (IV) chloride. Five different proportions - polymer to additive - were selected for casting films from common solvent. TG, DTG and DTA were employed to monitor thermal degradation of the systems. IR and py-GC-MS helped identify the decomposition products. The blends start degrading at a temperature lower than that of the neat polymer and higher than that of the pure additive. Complex formation between tin of additive and carbonyl oxygen (pendent groups of MMA units) was noticed in the films soon after the mixing of the components in the blends. The samples were also heated at three different temperatures to determine the composition of residues left after the expulsion of volatiles. The polymer, blends and additive exhibited a one step, two-step and three-step degradation, respectively. $T_0$ is highest for the polymer, lowest for the additive and is either $60^{\circ}C$ or $70^{\circ}C$ for the blends. The amount of residue increases down the series [moving from blend-1 (minimum additive concentration) to blend-5 (maximum additive concentration)]. For blend-1, it is 7% of the original mass whereas it is 16% for blend-5. $T_{max}$ also goes up as the concentration of additive in the blends is elevated. The complexation appears to be the cause of observed stabilization. Some new products of degradation were noted apart from those reported earlier. These included methanol, isobutyric acid, acid chloride, etc. Molecular-level mixing of the constituents and "positioning effect" of the additive may have brought about the formation of new compounds. Routes are proposed for the appearance of these substances. Horizontal burning tests were also conducted on polymer and blends and the results are discussed. Activation energies and reaction orders were calculated. Activation energy is highest for the polymer, i.e., 138.9 Kcal/mol while the range for blends is from 51 to 39 Kcal/mol. Stability zones are highlighted for the blends. The interaction between the blended parts seems to be chemical in nature.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.14 no.2
• /
• pp.136-150
• /
• 2002

To improve the water quality of the recently constructed Siwhaho, sluice gates were operated to allow free exchange of water with the sea. This estuarine lake connected to the outer sea through narrow gates is affected mainly by flushing by gate operation and river flows and wind forcing sometimes. As a predicting tool far the water qualities, a three-dimensional finite volume model CE-QUAL-ICM is incorporated into a finite element hydrodynamic model, TIDE3D. In coupling these two different modules, a new error minimization technique is applied by considering conservation of mass. Model tests for one year after calibration and validation using field observation show that eutrophication and other biological changes reach quasi-steady state after initial 60 days of simulation, thus it would be necessary to consider moderate ramp up option to remove initial uncertainties due to cold start option. Sediment-water interaction might not be a concern in the long-term simulation, since its effect is negligible. Simulated results show the newly applied scheme can be applied with satisfaction not only fur lessening of eutrophic processes in an estuarine lake but also looking for some active circulation to improve water quality.

• Journal of Korean Academy of Nursing
• /
• v.28 no.1
• /
• pp.117-131
• /
• 1998

The purpose of this study was to develop a critical pathway for case management for patients who have received Coronary Artery Bypass Graft (CABG) because of Ischemic Heart Disease(IHD) which is a factor of rising medical expenses. For this study. a conceptual framework was developed through a review of the literature including six critical pathways which are currently being used in USA. In order to identify the overall service contents required by these patients and to draw up a preliminary critical pathway, 30 cases of medical records of patients who had CABG because of IHD between January, 1995 to June. 1996 at the Cardiovascular Center of Yonsei Medical Center in Seoul were analyzed. An expert validity test was done for the preliminary critical pathway and clinical validity test was also done using seven IHD patients with CABG between November 11 and 23, 1996. After these processes. the final critical pathway was developed. The results of this study are summarized as follows : 1. The vertical axis of the critical pathway includes the following eight items : tests, nutrition, medications, consultations, activity, assessments, treatments, education discharge planning and the horizontal axis includes the time from the start of hospitalization to discharge. 2. Analysis of the 30 medical records indicated that the average length of stay was 20.2days with the average length of stay from hospitalization day to operation day being 6.2 days, and the average length of stay from operation day to discharge day was 13. 9 days. Analysis of the service contents showed that the horizontal axis of the preliminary critical pathway was set from hospitalization to the 14th post operation day and the vertical axis was set to include eight items, the contents which ought to have occurred, according to the time frames of the horizontal axis. 3. As a result of the experts validity, it was found that among the total of 571 items. there was over 83% agreement for 482 items, less than 83% for 89 items, which were then deleted and a revision of the critical pathway was done. 4. A clinical validity test was done using seven IHD patients with CABG. During the process, three patients were deleted because they were out of the criteria the investigator set. Finally, four patients were used. The result of study indicated that only one patient was discharged on the tenth post operation day, which was one day later than the expected day. Three patients were discharged later than the expected day from three days to nine days. All the cases progressed on schedule until the operation day and the first post operation day, but from the second post operation days, there were differences between the critical pathway and the actual practice. The differences came from tests, assessments, and treatments. 5. On the basis of the results of the clinical validity test. the following revisions in the final critical pathway were made : the transfer from ICU to step down ward would be the second post operation day, and the transfer to a general ward, the fifth post operation day, for patients who complained of lack of sleep from the fifth post operation day to discharge, a sleeping pill would be prescribed, skin observations would be performed routinely from immediately after the operation until the third post operation day, and would continue if there was a sign of skin injury on the fourth post operation day, and assessment of chest pain would be done from the third post operation day, and the “stairs climbing” item, expected to be done on the ninth post operation day would be deleted. In conclusion, this critical pathway is partially applicable to the care of patients with CABG but there are some parts needed to be further investigated.