• Journal of the Korea Safety Management & Science
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• v.25 no.1
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• pp.67-74
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• 2023

This study aims to measure sedimentation status change with the changes in internal pressure for dry chemical extinguishers of various use periods and analyze the suitability of the fire extinguishers' performance criteria. When the internal pressure of the fire extinguisher is 0%, 2 out of 10 new dry chemical powders for the 5 elapsed years were noted to be suitable, including 3 recycled dry chemical powders with 5 elapsed years that were found eligible. One out of 10 new dry chemical powders for 10 elapsed years was shown as suitable. Also, one new dry chemical powder for 13 elapsed years was suitable. When the internal pressure of the fire extinguisher was 50%, all 10 out of 10 new dry chemical powders for 5 years, recycled one with 5 elapsed years, and a new one with 10 elapsed years were found to be suitable, while 9 new dry chemical powders for 13 years were shown as suitable. When the internal pressure of the fire extinguisher was normal, new ones with 5 elapsed years, recycled ones with 5 elapsed years, new ones with 10 elapsed years, and new ones with 13 elapsed years were all 10 out of 10 samples noted as suitable. In summarizing the experiment results, it was found that the sedimentation status, one of the fire extinguisher's physical properties experiments, affects the fire extinguisher's performance criteria rather than the change with use periods.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.5
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• pp.755-763
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• 2010

Fine sediment loadings from agricultural watersheds have led to habitat degradation in Lake Takkobu, northern Japan. Fifteen lake sediment core samples were obtained and analyzed to develop a chronology using physical sediment characters, $^{137}Cs$, and tephra. The reconstructed sedimentation rates over the past ca 300 years suggested that sedimentation rates increased drastically after land use development. With a natural sedimentation rate of 0.1-1.1 mm $year^{-1}$ until 1898, lake sedimentation accelerated to 0.6-12.8 mm $year^{-1}$ after 1898. The sedimentation rates after land use change, such as forestry, river engineering works, and agricultural development, were about 6-12 times higher than that under natural conditions, leading to accelerated lake shallowing over the last ca 100 years. Sedimentation rates between 1898 and 1963 differed with location in the lake because of spatial variation in the sediment flux from the contributing rivers and their watersheds. The sedimentation rate in the southern zone between 1898 and 1963 was significantly higher than that in the middle and northern zones, reflecting active sediment production associated with forestry for charcoal production and canal construction for transportation in the southern watersheds and wetlands. The sedimentation rate after 1963 did not vary among the three zones, because decreasing sedimentation was found in most of the southern sites whereas an increasing trend was observed in the middle and northern sites. This result can be explained by shallowing of lake-bottom morphology with sedimentation and the resultant reduction of sediment retention capacity in the southern zone. Moreover, the sedimentation rate at sampling sites close to river mouths increased by 5-32 times compared with natural rates before 1898. The Kushiro River, into which Lake Takkobu drains under regular flow conditions, further contributed to an increased sedimentation rate, because water from the Kushiro River flows back into Lake Takkobu during floods.

• Korean Journal of Clinical Laboratory Science
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• v.39 no.2
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• pp.86-90
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• 2007

Intestinal parasitic infections remain a serious public health problem globally and have usually been associated with human malnutrition. This study was performed to observe the present status of intestinal helminthes infections among the primary school children in Iksan, Korea, during the period from June to August, 2006. A total of 974 fecal samples (male 479, female 495) were collected and examined by formalin-ether sedimentation technique for intestinal helminthes eggs. Of the 974 samples examined, 2 (0.2%) were egg positive for intestinal helminthes, and only eggs of Clonorchis sinensis were observed in the 2 cases. These C. sinensis egg were found in grade 5 (male, 1 case) and grade 6 (female, 1 case), respectively. The egg positive rate of male and female were 0.2%, respectively. Through this survey, I found that the C. sinensis infection is prevalent among primary school children in Iksan, Jeonbuk, and a continuous health education for school children is recommended to prevent the potential infection of C. sinensis.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.16 no.4
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• pp.224-232
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• 2004

Sedimentation changes related with bottom shear stress attenuation at JangHang channel in the Keum River Estuary, where several huge coastal constructions including an estuarine dam have been conducted for last 2 decades, were evaluated for 7 cases to figure out passage hindrance through the channel by a hydrodynamic model using hind-casting technique from 1988 to 2000 at every 2 years interval. Due to the construction of Keum River Estuary Dam, the maximum bottom shear stress rapidly lessened to $0.2-0.6N/m^2$ compared to$1-2N/m^2$ in natural status. Especially it marks below the critical shear stress of $0.4N/m^2$ resulting in severe siltation in the channel just after the closing of dam gates in 1994. It is concluded that the dam may block the tidal energy propagation to upstream and directly results in sedimentation environment in front of dam site. It is also revealed that at least 20% of passage hindrance of small fishing boats through the channel could be counted due to sedimentation by analysis of predicted mean spring tides.

• Journal of Korean Society of Water and Wastewater
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• v.23 no.6
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• pp.743-752
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• 2009

One of the major problems associated with operation of domestic sewer lines involves hydraulic problems such as insufficient conveyance capacity, exceeding maximum velocity, and deficiency of minimum velocity. It has also been pointed out that influent concentration lower than design concentration of pollutants, which is mainly caused by unidentified inflow and infiltration, degrades the operational efficiency of many sewage treatment plants (STPs). A computer-added analysis method supporting a coupled simulation of sewage quality and quantity is essentially required to evaluate the status of existing STPs and to improve their efficiency by a proper sewer rehabilitation work. In this study, dynamic water quality simulations were conducted using MOUSE TRAP to investigate the principal parameters that governs the changes of BOD, ${NH_4}^+$, and ${PO_4}^{3-}$3- concentrations within the sewer networks based on data acquired through on-site and laboratory measurements. The BOD, ${NH_4}^+$ and ${PO_4}^{3-}$3- concentrations estimated by MOUSE TRAP was lower than theoretical pollution loads because of sedimentation and decomposition in the sewer. The results revealed that sedimentation is a most important factor than other biological reactions in decreasing pollutant load in the sewers of C-city. The sensitivity analysis of parameters pertaining to water quality changes indicated that the effect of the BOD decay rate, the initial DO concentration, the half-saturation coefficient of dissolved BOD, and the initial sediment depth is marginal. However, the influence of settling rate and temperature is relatively high because sedimentation and precipitation, rather than biological degradation, are dominant processes that affect water quality in the study sewer systems.

• Parasites, Hosts and Diseases
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• v.39 no.2
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• pp.201-203
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• 2001

The present study was undertaken to know the infection status of Cryptosporidium parvum among the residents of Chorwon-gun, Kangwon-do in 1993. Total 461 fecal samples were collected from the inhabitants residing in Chorwon-gun during the period of August 12 to September 14, 1993. Fecal smears were prepared by formalin-ether sedimentation, and examined after modified acid fast staining. Of the 461 fecal samples,9 (1.9%) were positive for C. parvum oocysts. The positive cases were limited to thirties (4) patients, forties (3), and sixties (2) , and no oocyst was detected in other age groups. The oocyst positive rate for male was 1.4% and that of female was 2.6%.

• Journal of Pharmacopuncture
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• v.17 no.1
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• pp.20-26
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• 2014

Objectives: The study aimed to determine changes in laboratory data for cancer patients receiving Korean medicine (KM) care, with a focus on patients' functional status, cancer-coagulation factors and cancer immunity. Methods: We conducted an observational study of various cancer patients in all stages admitted to the East-West Cancer Center (EWCC), Dunsan Korean Hospital of Daejeon University, from Mar. 2011 to Aug. 2011. All patients were under the center's multi-modality Korean-medicine-based inpatient cancer care program. The hospitalization stay at EWCC ranged from 9 to 34 days. A total of 80 patients were followed in their routine hematologic laboratory screenings performed before and after hospitalization. Patients were divided into three groups depending on the status of their treatment: prevention of recurrence and metastasis group, KM treatment only group, and combination of conventional and KM treatment group. The lab reports included natural killer cell count (CD16 + CD56), fibrinogen, white blood cell (WBC), lymphocytes, monocytes, neutrophil, red blood cell (RBC), hemoglobin, platelet, Erythrocyte Sedimentation Rate (ESR), and Eastern Cooperative Oncology Group (ECOG) performance status. Results: With a Focus on patients' functional status, cancer-coagulation factors and cancer immunity, emphasis was placed on the NK cell count, fibrinogen count, and ECOG scores. Data generally revealed decreased fibrinogen count, fluctuating NK cell count and decreased ECOG, meaning improved performance status in all groups. The KM treatment only group showed the largest decrease in mean fibrinogen count and the largest increase in mean NK cell count. However, the group's ECOG score showed the smallest decrease, which may be due to the concentration of late-cancer-stage patients in that particular group. Conclusions: Multi-modality KM inpatient care may have positive effect on lowering the cancer coagulation factor fibrinogen, but its correlation with the change in the NK cell count is not clear.

• Parasites, Hosts and Diseases
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• v.38 no.4
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• pp.275-277
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• 2000

The status of intestinal parasite infections was investigated in two rural villages (Chitrasar, Jerona) in Chitwan District, Nepal in 1999. Stool examination was performed with a total of 300 specimens from schoolchildren by formalin-ether sedinentation technique. The prevalence rate of intestinal parasite infections in the surveyed areas was 44.0%. The prevalence rate in Jerona was slightly higher than that in Chitrasar. The prevalence rate of intestinal parasite infections in female was slighly higher than that in male without statistically significant difference. Entamoeba coli was the most commonly found protozoan parasite (21.0%) followed by Giardia lamblia (13.7%) and others (5.3%). Hookworm was the most prevalent intestinal helminth (13.0%) followed by Trichuris trichiura (3.0%) and others (5.0%). forty-three specimens (14.3%) Showed mixed infections. It is necessary to implement large-scale treatment with anthelminthics, health education and sanitary improvement for intestinal parasite control in the surveyed areas.

• Journal of Korean Society of Water and Wastewater
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• v.9 no.4
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• pp.97-106
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• 1995

An improving example for traditional rapid mix system was studied in the base of mechanisms of alum coagulation. Local status of the major water treatment plants was also investigated and evaluated for upgrading these plants. A new design and operating criterium for rapid mix system was proposed to velocity gradient, G of $1,000-1,500sec^{-1}$ and detention time, t of 1 sec from the results of experiments and literature reviews. Comparing the present rapid mix system to this criterium, apparent difference existed between them. In this study, for improving Seongnam water treatment plant, a design criterium of velocity gradient, and detention time was set to $1,100sec^{-1}$, 1 sec, respectively. A new rapid mix system adopted the nozzle injection countcurrently cross the inlet pipe to the whole area. The injection velocity was 17m/s, nozzle diameter was 1.0mm, and number of nozzle was 70. The new modified system without running present four 75 HP agitators was able to improve water quality(based on sedimentation effluent) by 15-35% and to reduce electrical energy by 98%.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.05a
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• pp.142-143
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• 2017

An analysis of the current water leak status of understand structure (underground parking lots, staircases, plumbing systems, water reservoirs, etc.) of multi-family housing in South Korea shows that water leaks are found from cracks in all areas of the underground structure caused by the degradation environment (water pressure by underground water, humidity, temperature, earth pressure, soil behaviour and vibration, etc.), which result in various problems, including mold, malodour, debonding of finishing materials, exfoliation, breakout, water leaks in electrical boxes, efflorescence, sedimentation of calcium hydroxide, decoloration, rusting, damages and pollution among others. Therefore, this study aims to analyse the current status of water leaks in underground structure and use the results as the basic data for developing a standard guideline for water leaks and maintenance by parts of the underground structure of multi-family housing.