• Hwankyungkyoyuk
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• v.20 no.4
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• pp.65-83
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• 2007

The purpose of this study was to survey science teachers, perception and attitudes on disposal of school laboratory waste water and materials. To fulfill this aim, a questionnaire was administered to 244 secondary school science teachers. The result of this study revealed that there was no large disparity in the degree of understanding of laboratory waste disposal and the laboratory waste water treatment, and in secondary science teachers' perception and practicing attitude on the environment. While science teachers had deep understanding of laboratory waste disposal and its influence on environmental pollution, they expressed less positive attitude toward the actual disposal of waste materials and waste water, and participation in teacher training. Therefore, it is necessary to provide standards of systematized disposal methods and proper disposal facilities in middle and high school laboratories, as well as to investigate teachers' needs before providing teacher training program.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.04a
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• pp.348-351
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• 2003

Trichloroethylene, which is one of the representative DNAPL, has been found in underground water sources as a result of the manufactural use, and disposal of the chemical. In this research, in situ air sparging method was chosen to reduce the TCE concentration from the source zone. The concentration reduction in the source zone resulting from air sparging is simulated using the modified STOMP Water-Air operational mode in a two dimensional axisymmetric domain and bench scale test is conducted to analyze the performance of air sparging. The results of laboratory tests are compared with numerical simulations.

• Hwankyungkyoyuk
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• v.2 no.1
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• pp.69-83
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• 1991

The management and disposal of harzardous chemicals from the middle school science class was studied for the safety of student and for the protection of the environment. This study was undertaken by analysis of 5 kinks of current middle school science text book and questionnaire survey, and reviewed on the recommended methods for the disposal of harzardous chemical wastes from science class. There are 237 chemicals determined in the middle school science text books and 87 among them actually used in middle school science laboratory. 51 chemicals are classified as harzardous ones and 49 highly hazardous according to the 'Law of Toxic Chemicals management'. 116 chemicals are defined as water pollutants and 10 are highly hazardous water pollutants according to the 'Water Quality Control Law' as well are 91 chemicals as air pollutants and 19 are highly hazardous air pollutants according to the 'Air Quality Control Law' Questionnaire survey results the identification of toxic chemicals, need for education, awareness of toxic effects and current problems in the management. Disposal of toxic chemicals in middle school science class has been undertaken without any treatment, which could be caused of environmental pollution. Most of science teacher wanted to have opportunities to attend supplement courses for the management and disposal of chemicals for the safety and environmental protection. Simple and applicable methods for the management and disposal of chemicals at middle school science level should be strongly recommended to be installed.

• Advances in concrete construction
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• v.12 no.6
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• pp.461-467
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• 2021

Polyethylene-terephthalate (PET) from bottle waste and linear low-density polyethylene (LLDPE) from barrels and tanks waste are widely available and need to be recycled. Recycling them in concrete and mortar is an alternative solution for their disposal. In this study various quantities of sand (5%, 10%, 15% and 20%) were substituted by powder from LLDPE waste. In addition, PET waste fibers (corrugated, straight) were added to the mortar with different percentages (0.5%, 1%, 1.5% and 2%) of cement mass. This paper evaluate the mechanical and physical properties of the composites in fresh (workability, air content and density) and hardened state (compressive and flexural strength, water absorption and total shrinkage). From the experimental results, it can be concluded that the strengthening in tensile of the mortar with plastic waste corrugated fibers is improved. Other important results are that the water absorption and the density rate are less than that of the ordinary mortar.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.19 no.4
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• pp.517-532
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• 2021

Safe geological disposal of spent nuclear fuel (SNF) requires knowledge of the deep hydrochemical characteristics of the repository site. Here, we conducted a set of deep hydrochemical investigations using a 750-m borehole drilled in a model granite system in Wonju, South Korea. A closed investigation system consisting of a double-packer, Waterra pump, flow cell, and water-quality measurement unit was used for in situ water quality measurements and subsequent groundwater sampling. We managed the drilling water labeled with a fluorescein dye using a recycling system that reuses the water discharged from the borehole. We selected the test depths based on the dye concentrations, outflow water quality parameters, borehole logging, and visual inspection of the rock cores. The groundwater pumped up to the surface flowed into the flow cell, where the in situ water quality parameters were measured, and it was then collected for further laboratory measurements. Atmospheric contact was minimized during the entire process. Before hydrochemical measurements and sample collection, pumping was performed to purge the remnant drilling water. This study on a model borehole can serve as a reference for the future development of deep hydrochemical investigation procedures and techniques for siting processes of SNF repositories.

• Nuclear Engineering and Technology
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• v.10 no.3
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• pp.153-163
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• 1978

The problems of solid waste disposal into the ground in connection with environmental aspects in the vicinity of a site would be very significant, though ground disposal for solid waste is safe and economical method. Studies of the waste-movement and migration of radionuclides (Sr-90 and Cs-137) for the disposal into the ground were performed under laboratory and field conditions. Affinity of the soils for radionuclide solution was higher than that in the acid solution. The sorption of radionuclides by the soils showed a time-dependent reation. The migration rates of radiostrontium and radiocesium were a range of 3.73$\times$10$^{-3}$ to 10.9$\times$10$^{-3}$ cm/day. The nuclides in the soil migrate much more slowly than the water, probably due to its high exchange capacity. The observed distribution of tritium was compared with that calculated by a mathematical model based on diffusivity. This study suggests that the tritiated water can be used to trace the movement of ground water.

• Journal of Korea Foundry Society
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• v.20 no.1
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• pp.3-12
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• 2000

The lead content of drinking water has been restricted to less than 15 ppb by Environmental Protection Agency (EPA) in USA. This has led to extensive research and development work at the Materials Technology Laboratory (MTL) of CANMET, a Canadian Government research laboratory, on the development of low-lead and lead-free copper alloys for plumbing applications. Attentionhas also been focused on the environmentally friendly and energy efficient permanent mold casting process to minimize the disposal of foundry sand contaminated by lead due to the use of leaded alloys in the non-ferrous foundries. A new series of alloys called SeBiLOY contaning Bi and Se been introduced to replace lead in the leaded alloys. This paper addresses some important casting characteristics such as fluidity, hot tear resistance, mechanical properties and microstructure of lead-free alloys such as SeBiLOY III and low-lead alloys such as silicon brass, silicon bronze and yellow brass in gravity permanent mold casting.

• Nuclear Engineering and Technology
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• v.52 no.1
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• pp.115-122
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• 2020

A promising method for removal of Cs ions from water and their incorporation into stable crystal structure ready for safe and permanent disposal was described. Cs-exchanged X zeolite was hot-pressed at temperature ranging from 800 to 950 ℃ to fabricate dense pollucite ceramics. It was found that the application of external pressure reduced the pollucite formation temperature. The effect of sintering temperature on density, phase composition and mechanical properties was investigated. The highest density of 92.5 %TD and the highest compressive strength of 79 MPa were measured in pollucite hot-pressed at 950 ℃ for 3 h. Heterogeneity of samples obtained at 950 ℃ was determined using scanning electron microscopy. The pollucite hot-pressed at 950 ℃ had low linear thermal expansion coefficient of ~4.67 × 10^-6 K^-1 in the temperature range from 100 to 1000 ℃.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.9
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• pp.1266-1273
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• 2015

The effect of starch infusion on production, metabolic parameters and relative mRNA abundance was investigated in low yield lactating cows from 86 days in milk. Six Holstein cows fitted with permanent ruminal cannulas were arranged into one of two complete $3{\times}3$ Latin squares and infused with a starch solution containing 800 grams starch for 16 days. The three treatments were: i) ruminal and abomasal infusion with water (Control); ii) ruminal infusion with cornstarch solution and abomasal infusion with water (Rumen); iii) ruminal infusion with water and abomasal infusion with cornstarch solution (Abomasum). There were no significant differences (p>0.05) among the three treatments with low yield lactating cows in feed and energy intake, milk yield and composition, plasma metabolism, or even on gene expression. However, cows receiving starch through rumen performed better than directly through the abomasum during the glucose tolerance test procedure with a higher area under the curve (AUC; p = 0.08) and shorter half-time ($t^{1/2}$; p = 0.11) of plasma insulin, therefore, it increased glucose disposal, which stated a lipid anabolism other than mobilization after energy supplementation. In conclusion, extra starch infusion at concentration of 800 g/d did not enhance energy supplies to the mammary gland and improve the lactating performance in low yield lactating cows.

• Proceedings of the Korean Environmental Health Society Conference
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• 2005.12a
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• pp.51-53
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• 2005

Disposal of waterwork sludge is important problem in WTP(water treatment plant). Purpose of this study is treated municipal waste water chemically using sludge that is produced in waterwork plant by link to reutilize waterwork sludge. Municipal waste water that use in an experiment used is produced at C university, and is SS 220 mg/L, BOD 145 mg/L, COD 160 mg/L, T-N 52 mg/L and T-P 2.6 mg/L. Used Alum, polymer coagulant and coagulant aid (diatomite, powered activated carbon) as CaO, coagulant as alkaline aid by chemical treatment medicine. In case of does slow speed agitation and stations after pours waterwork sludge in sewage and alkaline aid and coagulant at rapidly mixing the colloidal creation speed is fast and fine colloids concentration was high but settling time is shortened a little and removal rate of pollutant improved by $60{\sim}99%$.