• Magazine of the Korean Society of Agricultural Engineers
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• v.45 no.2
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• pp.107-115
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• 2003

Dairy manure amended with crop and forest residues (moisture 69% wet basis, C/N 22) was composted in a 605 L pilot-scale vessel using continuous air flow (56 L/min) for 19 days. Three pilot-scale sawdust biofilters (moisture 63%, pH 5.0) were built to clean biological waste gas from the composting process. For each methods, two replicated experiments were monitored over a period of three weeks. The system was evaluated to determine the biofilter media depth that would be adequate for compost odour reduction. The compost air cleaning was measured based on ammonia gas concentration before and after passing through the biofilter. Ammonia gas removal efficiency over 3 weeks was 42, 75 and 87% at sawdust biofilter media depth levels of 202, 400 and 600 mm, respectively. Each sawdust biofilter was operated at a moisture content in the range of 60~62% (wb), a temperature from 15 to $25^{\circ}C$, an average pressure drop from 240 to 340 Pa and a detention time from 60 to 180 seconds during the biofiltration process.

• Transactions of the Korean hydrogen and new energy society
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• v.27 no.3
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• pp.311-317
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• 2016

This paper presents the flow characteristics of a ball valve used for a gas pipeline. Understanding of the internal flow of a ball valve is an important to analyze the physical phenomena of the valve. Present experimental study was performed by IEC 60534-2-3, the international standard for an industrial control valve testing procedure. Pressure measured at upstream and downstream of the valve, flow-rate and gas temperature passing the inside of the gas pipeline were measured with respect to valve opening rates. Throughout the experimental measurement of the ball valve, empirical equation of the pressure drop between the ball valve according to the mass flow rates is successively obtained using a polynomial curve fitting method. In addition, flow coefficient for determining the valve capacity is also analyzed with respect to valve opening rates using the curve fitting method.

• Journal of the Korean Institute of Gas
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• v.2 no.1
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• pp.47-52
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• 1998

To eliminate foreign substance like metal rust and sand in natural gas pipeline, 250um strainer filter is used present in Korea Gas Corporation. But particles smaller than 250um passing the filter have bad effects to the valves and the measuring equipments. In order to eliminate small paticle in the pipeline, it is necessary to cut down the pore size of filter When we cut down the pore size of filter, the pressure difference between the front of filter and that of the rear part is increasing and disturb normal condition of gas supply. So it is very important to control the condition between the pore size of filter and the pressure difference. In this study, using head loss coefficient K, the estimation method of efficiency of gas filter according to the pore size and the pressure difference is presented.

• Journal of East-West Nursing Research
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• v.11 no.1
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• pp.33-41
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• 2005

This study was conducted to identify the effect of meridian acupressure on defecation of patients with post spinal operation. The nonequivalent control group posttest only design was used. The data were obtained from 77 post spinal operative patients, 34 in the experimental 43 in control group in Y Hospital, Seoul, Korea. The neurosurgical unit A and B ward, assigned by matched sample by the name of operation such as laminectomy and posterior lumbar interbody fusion are performed. Meridian acupressure meant the method that an examiner presses response points distributed in the pass of energy vessel. In this study, meridian acupressure program was performed on as points in order of Hegue (LI-4), Zhigou (TE-6), Zusanli (S-36), Shangjuxu (S-37), Xiajuxu (S-39), Tianshu (S-25), Taichong (L-3) which was known to be related to large intestine. Data were collected from 1, July 2003 to 1, September 2003. Meridian acupressure program was carried out for 20 minutes 4 hours after operation twice daily. In order to evaluate the effect of meridian acupressure intervention, they were asked time of bowel recovery, gas passing, and defecation though questionnaire method. Data were analyzed by the SPSS/ WIN 11.0 program. The results of this study were summarized as follows; 1. Homogeneity tests of general characteristics and operation related characteristics of the experimental group and the control group were performed. General characteristics included age, sex, defecation habit, eating pattern, fluid intake, life style, activity, usage of laxative and etc. 2. Hypotheses were verification as follows; 1) Recovery of bowel sound of the experimental group who received meridian acupressure intervention was faster than that of the control group after spinal operation (t=-6.770,P=.000). 2) Time of gas passing of the experimental group who received meridian acupressure program was faster than that of the control group after spinal operation (t=-8.003, P=.000). 3) Time to defecation of the experimental group who received meridian acupressure program was faster than that of the control group after spinal operation (t=-9.026, P=.000). 4) Abdominal discomfort due to defecation of the experimental group who received meridian acupressure program was lesser than that of the control group after spinal operation (t=-3.431, P=.001). From these results, meridian acupressure intervention was effective for recovery of bowel sound, reduce time to gas passing, time to defecation and lessen abdominal discomfort due to defecation on post spinal operative patients. And therefore this intervention can probably considered on clinical practice.

• Economic and Environmental Geology
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• v.39 no.6 s.181
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• pp.711-717
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• 2006

In order to study gas hydrate, potential future energy resources, Korea Institute of Geoscience and Mineral Resources has conducted seismic reflection survey in the East Sea since 1997. one of evidence for presence of gas hydrate in seismic reflection data is a bottom simulating reflector (BSR). The BSR occurs at the interface between overlaying higher velocity, hydrate-bearing sediment and underlying lower velocity, free gas-bearing sediment. That is often characterized by large reflection coefficient and reflection polarity reverse to that of seafloor reflection. In order to apply depth migration to seismic reflection data. we need high performance computers and a parallelizing technique because of huge data volume and computation. Phase shift plus interpolation (PSPI) is a useful method for migration due to less computing time and computational efficiency. PSPI is intrinsically parallelizing characteristic in the frequency domain. We conducted conventional data processing for the gas hydrate data of the Ease Sea and then applied prestack depth migration using message-passing-interface PSPI (MPI_PSPI) that was parallelized by MPI local-area-multi-computer (MPI_LAM). Velocity model was made using the stack velocities after we had picked horizons on the stack image with in-house processing tool, Geobit. We could find the BSRs on the migrated stack section were about at SP 3555-4162 and two way travel time around 2,950 ms in time domain. In depth domain such BSRs appear at 6-17 km distance and 2.1 km depth from the seafloor. Since energy concentrated subsurface was well imaged we have to choose acquisition parameters suited for transmitting seismic energy to target area.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.10
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• pp.1002-1010
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• 2015

Natural gas hydrates are newly emerging as an environment-friendly source of energy to substitute for fossil fuels in the 21stcentury.NGHs are reported to holds much amounts of natural gas (up to 182 standard volumes of gas per volume of hydrate); they are easy to store and safe to carry at about minus 20 degree Celsius under atmospheric pressure because of the self-preservation phenomenon of gas hydrates. The transporting method by gas-ice-hydrate ship carriers has been introduced and developed by a variety of industry and research institutions. Our team has been conducted to develop NGH total systems, including a breakthrough NGH carrier for sea transportation, since 2011. The NGH pellet carrier does not require a separate cooling system for cargo, and the initial temperature is maintained through insulation of the cargo tanks throughout the transport to the final destination. The heat conducted from the exterior and passing through the insulation material of the hull should be cut off as much as possible, but heat inflow inside the cargo tank from an external source is inevitable during transport. In this study, the heat transfer in a cargo tank of a 115K NGH carrier was analyzed through simulation with a commercial CFD code to estimate the boil-off gas/boil-off rate on the developed carrier and understand major hazards that could significantly impact the safety of the vessel.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11a
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• pp.384.2-384
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• 2002

Compressor is a major noise source of air-conditioner. Especially, its low frequency band noise below 1000㎐ is very important because it will not be attenuated by passing through the cover panel and heat exchanger in air-conditioner. The factors affecting the low frequency band noise are studied by geometric similarity along with several experiments, and the low frequency noise is closely related with the discharge holes of muffler as well as the cavity of lower shell. (omitted)

• 한국연소학회:학술대회논문집
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• 2002.06a
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• pp.157-162
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• 2002

The characteristics of DeNOx conversion process by plasma/post-heating system with the simulated gas containing ethene is investigated experimentally. Without plasma treatment, $NO-NO_2$ conversion doesn't occur by $400^{\circ}C$ in a mixture of $N_2/O_2$ with a trace gas of ethene. But $NO-NO_2$ conversion occurs as temperature increases above $400^{\circ}C$. The NO can, however, be converted to $NO_2$ at lower temperatures by treating the gas mixture with non-thermal plasma. The $NO-NO_2$ conversion enhances further by passing the plasma treated gas through the post-heating furnace. Results show that 20%${\sim}50%$ more conversion of NO to $NO_2$ is observed when the temperatures of the post-heating furnace are maintained at $300^{\circ}C$ or $400^{\circ}C$. The additional $NO-NO_2$ conversion by post-heating is due to the reaction of ethene with the byproducts or radicals generated from the plasma reaction.

• Journal of Acupuncture Research
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• v.22 no.5
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• pp.11-20
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• 2005

Objectives : The purpose of this study was to compare differences in bowel movement in women who had an abdominal hysterectomy and were treated for 10 minutes with San Yin Jiao (SP6) acupressure at three different time periods. Methods : The design was a nonequivalent control group non-synchronized post test only design. The participants included 123 women, 30 in experimental group 1 (post anesthesia 30 min), 22 in the experimental group 2 (post anesthesia 4 hours), 23 in experimental group 3 (Post anesthesia 24 hours), and 48 in a control group. Data were collected using a structured questionnaire consisting of general characteristics, self reported time when gas was first passed. Differences in the time when first gas was passed among four groups were analyzed using ANOVA. Results : There was no a statistical difference among the 4 groups for the time when gas was first passed. Conclusion : It is necessary to replicate the study with sonographic data for bowel movement.

• Journal of Korean Elementary Science Education
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• v.23 no.2
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• pp.152-158
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• 2004

The purpose of this study was to find the difficulties and problems in the carbon dioxide production experiment and to suggest the device for the improvement. Many students have misconception for the smell of carbon dioxide. I found that the smell of carbon dioxide of producting through the experiment didn't concern with the quantity of calcium carbonate. I certificated that the smell of carbon dioxide was related with the concentration of hydrochloric acid. I built two trap applicaing suction in the gas production device to exclude fully the smell of carbon dioxide. So the smell of carbon dioxide was not present by passing the two trap. To find the ideal experimental conditions I perform the experiment step by step. As the result enough carbon dioxide to use for the property experiment was collected under the condition that is 60 mL of 3 molarity hydrochloric acid and 30 g calcium carbonate. I certificated to mesuring flowing quantity of carbon dioxide using the flow meter of carbon dioxide. In the improvement experiment of the property of carbon dioxide, I proposed the experiment device regarding as spreading of the gas and children's interest. To improve the problem of gas production experiment, I proposed the gas certification device using a thread.