• Korean Journal of Veterinary Service
• /
• v.15 no.1
• /
• pp.1-6
• /
• 1992

A survey on the dosage optimal time for the bovine fascioliasis was carried out from Jan. 1987 to Dec. 1990. The results were summarized as follows ; 1. The mean infection rate was 27.7% (1,662 heads were infected out of 3,247 heads In 205 herds). A seasonal infection rate was winter (34.6%) >spring(32.5%) >summer(24.7%) > autumn(22.8%) 2. In the density of the fasciola spp. egg of infected bovine feces remarks 79.6% on the range below 10. 3. The density of fasciola spp. egg is not directly proportinal to the infection rate, and remarks on the range from 5 to 20. 4. In the herds dosed vermifuge the appearance of the fasciola spp. egg is as follows ; 1∼3 months show 3.8% and 4∼6 months 8.5% 5. The dosage optimal time for the bovine fasciliasis is as follows ; 1) According to the monthly infection rate the first dosage optimal time is Dec and Feb and the second-Jun and Aug. 2) In the herd dosed vermifuge the dosage optimal time is to dose twice by 60 days interval after 3∼4 months from previous dosage.

• Proceedings of the Korea Concrete Institute Conference
• /
• 1992.04a
• /
• pp.19-22
• /
• 1992

Properties of concrete has effected on the dosage variation of AE superplasticizer agent, Therefore, this study is designed for analysis of concrete properies according to the dosage variation of AE superplasticizer agent , and is aimed to analyze the effect slump, air content, compressive strength, resistance of freezing-and-thawing and for presenting the reference data on the practical use.

• 제어로봇시스템학회:학술대회논문집
• /
• 2005.06a
• /
• pp.1318-1321
• /
• 2005

As recently raw water quality has been polluted as well as its quality has been remarkably varied according to season and region, the precise control of coagulant dosage is being keenly required in water treatment plants. The amount of coagulant is closely related to raw water quality such as turbidity, alkalinity, water temperature, pH, electrical conductivity, etc. Since the optimum quantity of chemicals is not yet finalized, so dosage rate must be decided by using jar test that takes one or two hours. Hereupon, the output signal of stream current and multi-regression on historical data were proposed to be applied to the coagulant dosing control. In consequence of applying the scheme to automatic determination of the dosage rate, it was testified that the determination of dosage rate was very effective in case it is performed as to real-time sensing of water quality and the output signal of stream current.

• Journal of Korean Society on Water Environment
• /
• v.33 no.1
• /
• pp.90-96
• /
• 2017

Many sewage treatment plants have applied the advanced technology of chemical coagulant system to remove phosporus in Korea. However there are some problems for the injection of optimum coagulant dosage. In order to solve these problems, the research related to the more cost-effective automatic total phosphorus coagulation control system using an EC(Electrical Conductivity) have been in progress. This study was conducted by the same process and operation method as the Lab-scale for public small town sewage treatment plant. First, it confirmed the correlation among the EC, PO4-P and coagulant dosage in the Lab-scale MSBR(Membrane Sequencing Batch Reactor) process. Next, it analyzed that correlation coefficient of EC and the coagulant dosage was 0.92 in the Full-scale MSBR process. As a result, not only T-P removal efficiency was doubled but also it satisfied the effluent water quality standard in a stable manner. In addition, by applying the automatic control system using the EC, compared to the fixed coagulant injection system the coagulant dosage could be reduced by 28%.

• The Korean Journal of Pharmacology
• /
• v.5 no.1
• /
• pp.23-28
• /
• 1969

Saponin, essential oil and fat oil fractions were fractionated from Panax Ginseng and their potentiating or inhibiting actions during the combined use of several central nervous system stimulants or depressants were observed to elucidate the possible role of Ginseng fractions on the central nervous system. Saponin, essential oil and fat oil fractions shortened nembutal sleeping time at low dosage (10 mg/kg) but contrarily they produced potentiation of nembutal hypnosis at high dosage (50mg/kg). In the toxicity study of amphetamine, saponin and essential oil fractions reduced the toxicity in aggregated mice at high dosage (100 mg/kg) but such decreased lethality was not observed in isolated mice. Ginseng fractions, especially high dose of saponin fraction (100mg/kg) prolonged the survival time after injection of convulsive dose of metrazol or cocaine and saponin fraction also prolonged the onset of cocaine convulsion at high dosage (100 mg/kg).

• Toxicological Research
• /
• v.13 no.1_2
• /
• pp.131-138
• /
• 1997

Group of 40 male and 40 female Sprague-Dawley rats were given daily intravenous injections of different dosage of Erythropoietin (EPO), 80 IU/ kg/day (low dosage group), 400 IU/ kg/day (middle dosage group), or 2000 IU /kg/day (high dosage group)for 4 weeks by tail vein according to Established Regulation of Korean National Institute of Safety Research (1994. 4. 14). Appearance, behavior, mortality, and food consumption of rats of treated groups were not affected during the experimental periods. No significant EPO (erythropoietin)-related changes were found in urinalysts, eye examination, hematology, serum chemistry, and organ weight. No histopathological lesions were observed in both control and treatment groups. Our results strongly suggest that no toxic changes were found in rat treated intravenously with EPO (erythropoietin)for 4 weeks.

• Advances in concrete construction
• /
• v.15 no.5
• /
• pp.333-348
• /
• 2023

Fast infrastructure development boosts the demand for shotcrete. Despite sand and stone being the most common coarse and fine aggregates for shotcrete, excessive exploration of these materials challenges the ecological environment. This study utilized an industrial solid waste, high-titanium heavy slag, blended with steel fibers to form Wet Shotcrete of Steel Fiber-reinforced High-Titanium Heavy Slag (WSSFHTHS). It investigated its workability, shotcrete performance and mechanical properties under different water-to-cement ratios, fly ash content, superplasticizer dosage, and steel fiber content. The tunnel excavation and support were investigated by conducting finite element numerical simulation analysis and was used in 3 tunnel lining pipes in Zhonggouwan tailing pond. The major findings are as follows: (1) The water-to-cement ratio (w/c ratio) significantly impacted the compressive strength of WSSFHTHS. The highest 28-day compressive strength of 60 MPa was achieved when the w/c ratio was 0.38; (2) Adding fly ash improved the workability and shotcrete performance and strength development of WSSFHTHS. The best anti-permeability performance was achieved when the fly ash constituted 15%, with the lowest permeability coefficient of 4.596 × 10-11 cm/s; (3) The optimum superplasticizer dosage for WSSFHTHS is 0.8%. It provided the best workability and shotcrete performance. Excessive dosage resulted in water bleeding and poor aggregate encapsulation, while insufficient dosage decreased flowability and adversely affected shotcrete performance; (4) The dosage of steel fibers significantly impacted the flexural and tensile strength of WSSFHTHS. When the steel fiber dosage was 45 kg/m³, the 28-day flexural and tensile strengths were 8.95 MPa and 6.15 MPa, respectively; (5) By integrating existing shotcrete techniques, the optimal lining thickness was 80 mm for WSSFHTHS per simulation. The results revealed that after using WSSFHTHS, the displacement of the tunnel surrounding the rock significantly improved, with no cracks or hollows, similar to the simulation results.

• Journal of Korean Society of Water and Wastewater
• /
• v.34 no.6
• /
• pp.411-423
• /
• 2020

To remove phosphorus from the effluent of public wastewater treatment facilities, hundreds of enhanced phosphorus treatment processes have been introduced nationwide. However, these processes have a few problems including excessive maintenance cost and sludge production caused by inappropriate coagulant injection. Therefore, the optimal decision of coagulant dosage and automatic control of coagulant injection are essential. To overcome the drawbacks of conventional phosphorus removal processes, the integrated sedimentation and dissolved air flotation(SeDAF) process has been developed and a demonstration plant(capacity: 100 ㎥/d) has also been installed. In this study, various jar-tests(sedimentation and / or sedimentation·flotation) and multiple regression analyses have been performed. Particularly, we have highlighted the decision-making algorithms of optimal coagulant dosage to improve the applicability of the SeDAF process. As a result, the sedimentation jar-test could be a simple and reliable method for the decision of appropriate coagulant dosage in field condition of the SeDAF process. And, we have found that the SeDAF process can save 30 - 40% of coagulant dosage compared with conventional sedimentation processes to achieve total phosphorus (T-P) concentration below 0.2 mg/L of treated water, and it can also reduce same portion of sludge production.

• Proceedings of the KSME Conference
• /
• 2007.05b
• /
• pp.3139-3143
• /
• 2007

The objective of this paper was to investigate the mixing characteristics of an three-stage inline coagulant mixing system experimentally. Wastewater samples of pH 8.5 and initial turbidity 1,000NTU were taken from a site of tunneling work. At the constant dosage, 0.36mL/L, of polymer as coagulant aids, the coagulation efficiency with the dosage of PAC as coagulant was about 4${\sim}$6% at 10 minutes after sampling. In the case of 2 different velocity gradient conditions, the efficiency of turbidity removal was increased about 6.5${\sim}$8% with increasing the dosage of coagulant while, the efficiency was increased about 20${\sim}$21.5% with increasing the dosage of coagulant aids. The efficiency of turbidity removal with the settling time after sampling was about 90% after 1 minute, and the efficiency was about 95% after 5 minutes.

• Journal of Biosystems Engineering
• /
• v.27 no.3
• /
• pp.259-266
• /
• 2002

It is crucial to know spatial soil variability for precision farming. However, it is time-consuming, and difficult to measure spatial soil properties. Therefore, there are needs fur sensing technology to estimate spatial soil variability, and for electronic mapping technology to store, manipulate and process the sampled data. This research was conducted to develop a real-time soil organic matter sensor and an electronic mapping system. A soil organic matter sensor was developed with a spectrophotometer in the 900∼1,700 nm range. It was designed in a penetrator type to measure reflectance of soil at 15cm depth. The signal was calibrated with organic matter content (OMC) of the soil which was sampled in the field. The OMC was measured by the Walkeley-Black method. The soil OMCs were ranged from 0.07 to 7.96%. Statistical partial least square and principle component regression analyses were used as calibration methods. Coefficient of determination, standard error prediction and bias were 0.85 0.72 and -0.13, respectively. The electronic mapping system was consisted of the soil OMC sensor, a DGPS, a database and a makeshift vehicle. An algorithm was developed to acquire data on sampling position and its OMC and to store the data in the database. Fifty samples in fields were taken to make an N-fertilizer dosage map. Mean absolute error of these data was 0.59. The Kring method was used to interpolate data between sampling nodes. The interpolated data was used to make a soil OMC map. Also an N-fertilizer dosage map was drawn using the soil OMC map. The N-fertilizer dosage was determined by the fertilizing equation recommended by National Institute of Agricultural Science and Technology in Korea. Use of the N-fertilizer dosage map would increase precision fertilization up to 91% compared with conventional fertilization. Therefore, the developed electronic mapping system was feasible to not only precision determination of N-fertilizer dosage, but also reduction of environmental pollution.