• Journal of Advanced Marine Engineering and Technology
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• v.34 no.6
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• pp.816-824
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• 2010

The forces applying to an object in the transferring pipe of waste are analyzed and the equation of motion is established in this paper. It is shown that the equation of motion becomes the 1st order non-linear differential equation. Using its general solution, the velocity of the object in the transferring pipe of waste can be expressed in the explicit form. Noting that the velocity of object is impact velocity to the elbow or curved part of the transferring pipe of waste, the kinetic energy of the object can be calculated and the necessary impact strength of inner wall is obtained. The velocity of object is also calculated and presented in the graphic forms with the condition of air velocity 30m/sec. The impact test of cast basalt tube is carried out by the free fall of a weight and the test results show that the impact strength of the cast basalt tube is sufficient to apply to protecting inner wall of the transferring pipe of waste.

• Journal of the Korean GEO-environmental Society
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• v.14 no.1
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• pp.61-68
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• 2013

This paper presents an experimental results on the environmental characteristics of waste tire. Experimental program includes a set of laboratory leaching tests and field pilot test for leachate analysis. Laboratory tests were conducted to illustrate how properties such as TOC, pH, turbidity and Zn change with tire sizes and drain conditions. In field pilot test, water samples were collected form a drainage system installed below the tire-reinforced retaining wall and analyzed for chemical quality. Laboratory leaching tests performed on various particle sizes of waste tire indicated that as tire size is increased, the concentration of leachate is decreased. In continuous flow column tests, the concentration of leachate decreased with the number of exposure periods or pore volumes flushed through the waste tire. However, during pause flow column tests, the concentration of leachates were increased with time. Field monitoring of effluent indicated that no significant adverse effects on ground water quality had occurred over a period of 12 months.

• Korean Journal of Agricultural Science
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• v.47 no.2
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• pp.375-380
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• 2020

The high intrinsic water content and salinity of food waste prevent a smooth composting process and consequently cause social, economic and environmental problems. In this study, we investigated the distribution of the water content and salinity in food wastes to obtain useful primary data to ensure adequate and quality recycling. A total of 300 food waste (FW) samples were collected from residential apartments (home generated FW), a wide range of restaurants, i.e., restaurant generated FW that included Korean, Chinese, Japanese and western FWs, and several places that included food waste processing facilities (dehydrated FW cakes). The collected food wastes were oven dried for 48 hours at 80℃ after which the water and salinity contents were analyzed. The results show that the average water content of the FWs was 72.45 ± 10.51%, and the average salinity content was 2.03 ± 0.57%. Furthermore, the salinity of the collected FWs was characterized by where the FW was generated. By location, the salinity concentration of home generated FW was 2.30% while western food had the lowest salinity concentration of 1.18%. However, dehydrated cakes had the highest salinity concentration of 2.84%. Especially, the distribution of the salinity content in food wastes can form the basis for improving the compost quality in food waste recycling.

• Clean Technology
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• v.26 no.2
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• pp.116-121
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• 2020

In this paper, the recycling of waste Ni-MH battery by-products for electric vehicle is studied. Although rare earths elements still exist in waste Ni-MH battery by-products, they are not valuable as materials in the form of by-products (such as an insoluble substance). This study investigates the recovering of rare earth oxide for solvent extraction A/O ratio, substitution reaction, and reaction temperature, and scrubbing of the rare earth elements for high purity separation. The by-product (in the form of rare earth elements insoluble powder) is converted into hydroxide form using 30% sodium hydroxide solution. The remaining impurities are purified using the difference in solubility of oxalic acid. Subsequently, Yttrium is isolated by means of D2EHPA (Di-[2-ethylhexyl] phosphoric acid). After cerium is separated using potassium permanganate, lanthanum and neodymium are separated using PC88A (2-ethylhexylphosphonic acid mono-2-ethylhexyl ester) and it is calcinated at a temperature of 800 ℃. As a result of the physical and chemical measurement of the calcined lanthanum and neodymium powder, it is confirmed that the powder is a microsized porous powder in an oxide form of 99.9% or more. Rare earth oxides are recovered from Ni-MH battery by-products through two solvent extraction processes and one oxidation process. This study has regenerated lanthanum and neodymium oxide as a useful material.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.165-170
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• 2001

The main purpose of this study is to generate a fine copper oxide powder of high purity, with a compact structure and a uniform particle size by a spray pyrolysis process. The raw material is a waste copper chloride solution formed in the manufacturing process of Print Circuit Board (PCB). This study also examines the influences of various factors on the properties of the generated powder. These factors include the reaction temperature, the inflow speed of the raw material solution, the inflow speed of the air, the size of the nozzle tip, and the concentration of the raw material solution. It is discovered that, as the reaction temperature increases from 80$0^{\circ}C$ to 100$0^{\circ}C$ , the particle size of the generated powder increases accordingly, and that the structure of the powder becomes much more compact. When the reaction temperature is 100$0^{\circ}C$, the particle size of the generated powder increases as the concentration of copper in the raw material solution increases to 40g/l, decreases as the concentration increases up to 120g/l, and increases again as the concentration reaches 200g/1. In the case of a lower concentration of the raw material solution, the generated powder appears largely in the form of CuO. As the concentration increases, however, the powder appears largely in the form of CuCl. When the concentration of copper in the raw material solution is 120g/1, the particle size of the generated powder increases as the inflow speed of the raw material solution increases. When the concentration of copper in the raw material solution is 120g/1, there is no evident change in the particle size of the generated powder as the size of the nozzle tip and the air pressure increases. When the concentration is 40g/1, however, the particle size keeps increasing until the air pressure increases to 0.5kg/$\textrm{cm}^2$, but decreases remarkably as the air pressure exceeds 0.5kg/$\textrm{cm}^2$.

• Steel and Composite Structures
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• v.51 no.3
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• pp.337-349
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• 2024

The growing quantity of tires and building trash piling up in landfills poses a serious threat to the stability of the ecosystem. Researchers are exploring ways to reduce and use such byproducts of the construction industry in an effort to promote greener building practices. Thus, using recycled crumb rubber from scrap tires in concrete manufacturing is important for the industry's long-term viability. This study examines the proportion of waste rubber in fiber form, specifically at weight percentages of 5%, 10%, and 15%. Moreover, the study examines the shear behavior of reinforced concrete beams. A total of twelve RC beam specimens, each sized 100 mm by 150 mm by 1000 mm (w × d × L), were constructed and positioned to the test. Various mixtures were designed with different levels of scrap tire rubber content (0%, 5%, 10%, and 15%) and Stirrup Vol. Ratio (2.10, 2.80, and 3.53) in reinforced concrete beams. The findings indicate that the inclusion of scrap rubber in concrete leads to a decrease in both the mechanical characteristics and weight of the material. This is mostly attributed to the lower strength and stiffness of the rubberized concrete. Furthermore, estimations generated by a variety of design codes were examined alongside the obtained data. In order to make a comparison between the estimates provided by the different codes such as ACI 318-14, CEB-FIB and Iranian national building codes, a calculation was done to determine the ratio of the experimental shear strength to the anticipated shear strength for each code.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.6 no.4
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• pp.347-356
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• 2008

The purpose of Radioactive Waste Acceptance Criteria(WAC) is to verify a radioactive waste compliance with radioactive disposal facility requirements in order to maintain a disposal facility's performance objectives and to ensure its safety. To develop WAC which is conformable with domestic disposal site conditions, we furthermore analysed the WAC of foreign disposal sites similar to the Kyung-Ju disposal site and the characteristics of various wastes which are being generated from Korea nuclear facilities. Radioactive WAC was developed in the technical cooperation with the Korea Atomic Energy Research Institute in consideration of characteristics of the wastes which are being generated from various facilities, waste generators' opinions and other conditions. The established criteria was also discussed and verified at an advisory committee which was comprised of some experts from universities, institutes and the industry. So radioactive WAC was developed to accept all wastes which are being generated from various nuclear facilities as much as possible, ensuring the safety of a disposal facility. But this developed waste acceptance criteria is not a criteria to accept all the present wastes generated from various nuclear facilities, so waste generators must seek an alternative treatment method for wastes which were not worth disposing of, and then they must treat the wastes more to be acceptable at a disposal site. The radioactive disposal facility WAC will continuously complement certain criteria related to a disposal concentration limit for individual radionuclide in order to ensure a long-term safety.

• Proceedings of the Korea Concrete Institute Conference
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• 1997.04a
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• pp.451-459
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• 1997

Current domestic building market is in the face of a tise in construction cost as a result of labor cost and materials problems, so improvements for productivity are doing their best for finding a way out of the difficulties. But the most of technical of from work is just considered the basic role and shape. As for environment protection, the utilization of waste concrete is important. But many of studies were interesting on the resource recycling for structural concrete. The purpose of this study is the development of thin precast form using recycled aggregate and the assembling systems for permanent form by cast-in-place.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.13 no.3
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• pp.181-186
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• 2015

It is necessary to develop an effective waste salt treatment technology for the minimization of radioactive waste generation from the pyroprocessing of spent nuclear fuel. For this reason, the separation characteristics of NdCl₃ from LiCl-KCl eutectic salt in a reactive distillation process using Li₂CO₃ or K₂CO₃ were observed. NdCl₃ was converted into oxychloride (NdOCl) or oxide (Nd₂O₃) in the reaction model between NdCl₃ and the carbonates using HSC-Chemistry, and this result was confirmed in the reactive distillation test of the LiCl-KCl-NdCl₃ system using the carbonates. Based on these results, the reactive distillation process conditions were determined to separate NdCl₃ into an oxide form (Nd₂O₃) which can be easily fabricated into a final waste form.

• Economic and Environmental Geology
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• v.29 no.2
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• pp.215-225
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• 1996

All the radionuclides in high-level nuclear waste will decay to harmless levels eventually but for some radionuclides decay is so slow that their radiation remains dangerous for times on the order of tens or hundreds of thousands of years. At the present time, the most favorite disposal plan for high-level radioactive waste is a mined geological disposal in which canister enclosing stable solid form of radioactive waste is placed in mined cavities locating hundred meters below the surface. The chief hazard in such disposal is dissolution of radionuclides from the waste in the groundwater that will eventually carry the dissolved radionuclides to surface environments. The hazard from possible escape of the radionuclides through groundwater can be delayed by engineered and geologic barriers. The engineered barriers can become useless by unexpected geologic catastrophe such as volcanism, earthquake, and tectonic movement and by fraudulent work such as careless construction, improperly welded canisters within the first few decades or centuries. As a result, dangerously radioactive waste which is still intensively radioactive is directly exposed to attack by moving groundwater. All the more, it is almost impossible to control repositories for times more than 10,000 years. Therefore, naturally controlled geologic, barriers whose properties will not be changed within 10,000 years are important to guarantee the safety of repositories of high-level radioactive waste. In Sweden and France, the suitability of granite for the mined geological disposal of high-level waste has been studied intensively. According to the research in Sweden and France, granites has the following physio-chemical characteristics which can delay the transportation of radionuclide by groundwater. First, the permeabilities of granites decreases as the depth increases and is $10^{-8}{\sim}10^{-12}m/s$ at depth below 300 m. Second, groundwater at depth below 300 m has pH=7-9 and reducing condition (Eh=-0.1~0.4). This geochemical condition is desirable to prevent both canister and solid waste from corrosion. Third most radionuclides are not transported by low solubilities and some radionuclide with high solubility such as Cs and Sr are retarded by absorption of geologic media through which ground water flows. Therefore, if high-level waste is disposed at depth below 300 m in the granite body which has a low permeability and is geologically stable more than 10,000 years, the safety of repositories from the hazard due to radionuclide escape can guaranteed for more than 10,000 years.