• The KSFM Journal of Fluid Machinery
• /
• v.5 no.3 s.16
• /
• pp.33-39
• /
• 2002

The head-capacity corves for pumps developed by the pump manufacturer are based on tests of a single pump operating in a semi-infinite pool with no nearby walls or floors and with no stray currents. Hence, flow into the pump suction is symmetrical with no vortices or swirling. Pump station designers rely on these curves to define the operating conditions for the pump selected. However, various constraints such as size, cost, and limitations on storage time require walls, floors, and pump intakes to be close proximity to each other. From this background, the authors are carrying out a systematic study on the flow characteristics of intakes within a sump found in pump stations. Model pump intake basin is designed and PIV is adopted as a measuring tool to capture the instantaneous flow patterns. Special attention is paid to investigate the flow patterns near the free surface, side-wall, and back-wall due to different clearances from back-wall to vortical intake pipe. Moreover, the locations and patterns of the various types of vortices that were found in the examinations are discussed.

• 유체기계공업학회:학술대회논문집
• /
• 2001.11a
• /
• pp.209-215
• /
• 2001

The head-capacity curves for pumps developed by the pump manufacturer are based on tests of a single pump operating in a semi-infinite pool with no nearby walls or floors and no stray currents, Hence, flow into the Pump suction is symmetrical with no vortices or swirling. Pump station designers rely on these curves to define the operating conditions for the pump selected. But various constraints such as size, cost, and limitations on storage time require walls, floors, and pump intakes to be close proximity to each other. From this background, the authors are carrying out a systematic study on the flow characteristics of intakes within a sump found in pump stations. Model pump intake basin is designed and PIV is adopted as a measuring tool to capture the instantaneous flow patterns. Special attention is paid to investigate the flow patterns near the free surface, side-wall and back-wall due to different clearances from back-wall to vertical in take pipe. Moreover, the locations and vorticities of the various types of vortices that were found in the examinations are discussed.

• Proceedings of the KSME Conference
• /
• 2001.11b
• /
• pp.563-569
• /
• 2001

The head-capacity curves for pumps developed by the pump manufacturer are based on tests of a single pump operating in a semi-infinite pool with no nearby walls or floors and no stray currents, Hence, flow into the pump suction is symmetrical with no vortices or swirling. Pump station designers rely on these curves to define the operating conditions for the pump selected. But various constraints such as size, cost, and limitations on storage time require walls, floors, and pump intakes to be close proximity to each other. From this background, the authors are carrying out a systematic study on the flow characteristics of intakes within a sump found in pump stations. Model pump intake basin is designed and PIV is adopted as a measuring tool to capture the instantaneous flow patterns. Special attention is paid to investigate the flow patterns near the free surface, side-wall and back-wall due to different clearances from back-wall to vertical in take pipe. Moreover, the locations and vorticities of the various types of vortices that were found in the examinations are discussed.

• Parasites, Hosts and Diseases
• /
• v.32 no.3
• /
• pp.201-204
• /
• 1994

Echinostomiasis is an endemic intestinal trematodiasis of humans in Korea We observed a human case of Echinostomn honense infection who had ulcerations on the duodenal mucosa. A 55-year old man living in Hamyang-gun, Kyongnam, complained of epigastric pain with hematemesis In April 1994. Endoscopy revealed lesions of early gastric cancer and duodenal ulcerations. A penetrating parasite into the duodenal mucosa was picked out, and identified as E. honense. As the patient was treated 10 praziquantel 10 mg/kg single dose,3 more E. hofene and 7 Metogonimw worms were recovered. This case demonstrates that echinostomiasis causes gross ulcerations in the duodenum.

• The Korean Journal of Physiology
• /
• v.16 no.2
• /
• pp.153-157
• /
• 1982

It has been hypothesized that the effectiveness of the popular mini-trampoline as a conditioning device is due to the increased gravitational forces which are imparted to every cell in the body during its use. This study evaluated a means of determining the acceleration forces on a subject using a minitrampoline. By cinematic evaluation, a plot of the changes in distance over time was obtained. Using the formulas developed at the Arizona State University Crash Survival Investigators' School, the maximum acceleration forces were determined to be approximately $3.2+G_z$.

• The Journal of the Acoustical Society of Korea
• /
• v.34 no.2
• /
• pp.146-156
• /
• 2015

This study investigated how the location of sound absorptive materials and sound diffusers affects the acoustic performance of small auditoriums. It was conducted for a standard model established with the averaged dimension of 36 auditoriums which had opened since 2000 in Daehak-ro, Seoul. In this study, the installation area of finishing materials was calculated upon a back wall which had the smallest installation effective area of finishing materials. To analyze the changes of acoustic performance according to installation location of finishing materials, experiments were carried out using the 1/10 down scale models for 8 cases which were made by classifying the installation location of ceiling and side wall into the front, middle and rear part.The used acoustic parameters were reverberation time (RT), early decay time (EDT), clarity (C80), definition (D50) and speech transmission index (STI). In result, the index related to the amount of reverberant sound (RT, EDT) showed the great changes when evaluating it through just noticeable difference (JND), but the one related to clarity (C80, D50, STI) hardly indicated the changes. In case to obtain short reverberation time, it was most effective to control reverberation time through the side walls when installing sound absorptive and diffusive materials, and side wall front was the location which could get the shortest reverberation time.

• The Journal of the Acoustical Society of Korea
• /
• v.35 no.2
• /
• pp.92-101
• /
• 2016

There are many results in which acoustical conditions of a classroom play an important role for studying effects and academic achievement of students. However, there are very few guidelines or design proposals which could make appropriate acoustic environment when classrooms are built or renovated. The present study suggests various design proposals satisfying acoustic standards of classrooms based on theoretical calculation and acoustic field experiments. At first, minimum area of sound absorption was calculated which is required to satisfy the acoustic standard for domestic middle and high schools. Also, room acoustic measurements were carried out in order to investigate the acoustic performance of an existing classroom by changing interior finishing materials on ceiling and rear walls. As a result, it was revealed that reverberation time standard below 0.8 s can be acquired even if there is no sound absorption on ceiling which is a general practice executed in Korea. Specially, it was found that if partial area of ceiling would be treated as reflective with the ratio of sound absorption and reflection as 2:1, almost similar acoustic parameters of $C_{50}$, $D_{50}$, RASTI (Rapid Speech Transmission Index) and higher sound levels could be acquired in comparison with the case of entire sound absorption on ceiling.