• Journal of the Korean Society of Safety
• /
• v.27 no.3
• /
• pp.96-103
• /
• 2012

The purpose of this study is evaluate the ability of coating materials developed in order to prevent the durability deterioration of the concrete structure. Neutralization test, freezing and thawing test, and sulfate resistance test were performed in this study. Test results show that the developed coating material is effective against durability deterioration.

• Korean Journal of Microbiology
• /
• v.7 no.2
• /
• pp.45-56
• /
• 1969

The rapid deterioration of fermented rice-wine, called Tak Joo and Yak Joo, is one of the serious problems for brewing and marketing in Korea. In this study the biochemical and microbiological investigations have been performed for extension of shelf-life of the rice-wine by the method of combined heat and radiopasteurization. Major microflora in this wine is proved as Saccharomyces cereoisiar, which is destroyed by h-at treatmznt ($70^{\circ}C$, 10 min.) combined with gamma-irradiation of 240 K, rads doses. The changes of chemical constituents of them were investigated during the storage period at room temperatures of summer days($33^{\circ}C$). The results of sensory test for gamma-irradiated rice-wine with lower doses show no significant unfavourable off-odor nor color change compared with the fresh rice-wine. Therefore, it is revealed that the combined process makes possible extension of shelf-life of fermented rice-wine in markets without any deterioration and loose of its particular tastes at least for three weeks.

• Journal of Conservation Science
• /
• v.6 no.1 s.7
• /
• pp.79-88
• /
• 1997

It is important and urgent matters to conserve books and documents. Causes to the deterioration of papers, chemical methods to prevent or retard the deterioration of papers. physical methods to preserve the deteriorated papers, preparation of alkaline papers of which hydrolysis is very slow compared with acid ones, and recent requirements for papers used in books and documents are reviewed and discussed.

• Journal of Korean Society of Water and Wastewater
• /
• v.20 no.4
• /
• pp.545-558
• /
• 2006

The current conditions of large water mains are evaluated by deteriorations and the causes of deterioration are investigated through visual assessments in the field, mechanical tests and analysis of chemical compositions in laboratory for each pipe material, unlined cast iron pipes (CIPs), ductile iron pipes (DCIPs) and steel pipes (SPs) Tubercles and scales from internal and external corrosion of unlined cast iron pipes were identified as the causes of functional performance limitations in large water mains. It is investigated that main causes of internal and external corrosion of water pipes are from lots of depositions of organic and inorganic substances on pipe surface, concentrated pitting, and uniform corrosion by local or global exfoliation or detachment of lining and coatings of DCIPs and SPs. Internal and external corrosion depths of CIPs were higher than those of DCIPs and SPs. Consequently, total corrosion rate summed internal and external corrosion rates of CIPs also were shown to be higher than those of DCIPs and SPs. The failure time from hole generation of CIPs by total corrosion rate was predicted to be taken sixteen years, and DCIPs and SPs were twenty-six years and one hundred and fifty three years. And longitudinal deflection of investigated water mains were not happened and mechanical strengths such as tensile strength, elongation, and hardness also were mostly suited to Korea Standards. It was thought that the weakness of tensile strength of one sample(S-11) was, however, due to higher carbon contents(%) in CIPs. Pipe deterioration score of S-46 was 55.2 and was preferentially assessed to be rehabilitated.

• Journal of Conservation Science
• /
• v.29 no.2
• /
• pp.93-102
• /
• 2013

The wooden Ksitigarbha Triad Statues (Treasure No. 1749) of Shinhungsa temple in Sokcho are enshrined in the inside of the Myeonbujeon Hall. The Statues are highly damaged physical weathering which are crack and exfoliation. Also, the Statues were deteriorated by chemical and biological weathering. This study carried out nondestructive method as deterioration map, ultrasonic measurement, X-ray and endoscopy survey for deterioration evaluation and conservation plan. As a result, Ksitigarbha Statue coated by dust and various pollutants. And gold-gilt of Statue's surface has peeled off. Head part of Mudokguiwang Statue was discolored from water leak in Myeongbujeon Hall. Domyeongjonja Statue is highly damaged by insects. Result of endoscopy, there were bee hives in the inside of the Statue. Therefore, we suggest that these Statues have need to do conservation treatment on the basis of diagnostic results.

• Journal of the Korean institute of surface engineering
• /
• v.55 no.4
• /
• pp.231-235
• /
• 2022

As environmental pollution becomes more serious, the demand for electric vehicles (EVs) and lithium-ion batteries for electric vehicles is rapidly increasing worldwide. Accordingly, the amount of waste batteries is also increasing, and a technology for recycling and reusing them is required. In order to reuse a used battery, it is necessary to non-destructively diagnose the deterioration condition of the battery. Therefore, in this study, we investigate the diagnosis of degradation for parallel-connected lithium-ion battery cells through non-constructive electrochemical approach. As the number of parallel-connected cells increased, in addition to linear degradation, abrupt step-like degradation occurred, which is attributed to the predominant degradation of specific cells. In addition, it is confirmed that deteriorated cells among multiple cells can be distinguished through a simple measurement of open circuit voltage (OCV).

• Economic and Environmental Geology
• /
• v.28 no.5
• /
• pp.519-525
• /
• 1995

Recently, there have been several cases of serious accidents on concrete structure resulting from rapid deterioration of concrete strength. On the view point of long term stability of concrete, deterioration of concrete strength is mostly due to chemical reaction between alkali and reactive aggregates (alkali-aggreagte reaction; AAR) in concrete rather than a problem of execution. For long-term stability of concrete, concrete aggregates must be carefully selected. Some of rocks used for concrete aggregates contain deleterious minerals reactive to alkali components in concrete. Most of AAR result from chemical reaction between alkali components and reactive silica minerals in aggregates (so called alkali-silica reaction; ASR). The silica minerals are as follows; quartz with seriously distorted lattice structure, volcanic glass, chalcedony, opal, cristobalite, tridymite, etc. ASR may cause expansion and cracks, further collapse in concrete structure, in a few years. In case of crushed aggregates, only a part of rock mass without reactive minerals must be produced in aggregates mine after thorough examination of the distribution of rocks with reactive minerals. In case of natural aggregates, the total content of reactive minerals must be calculated, if, the content is more than 20%, the rate should be lower by mixing other non-reactive crushed- or natural aggregates. If it is obliged to use concrete aggregates all containing deleterious minerals in a discrete area, they must be used with low alkali cement Even if it is low quality in the chemical properties, aggregates with suitable range in the physical properties can be utilized as the aggregate of other purposes.

• Journal of Conservation Science
• /
• v.33 no.4
• /
• pp.241-254
• /
• 2017

The Stone Guardian and Memorial Tablets from the Muryeong Royal Tomb are composed of the same kind of plutonic igneous rocks, the so-called hornblendite. Color of the rocks show greenish gray, and both of them occurred with medium-grained granular texture. The rock-forming minerals composed mainly of amphibole and plagioclase. Magnetic susceptibility of the Stone Guardian is 0.15 to 0.63 (mean $0.42{\times}10^{-3}SI\;unit$), the King's Stone Memorial Tablet is 0.11 to 0.38 (mean $0.24{\times}10^{-3}SI\;unit$) and the Queen's Stone Memorial Tablet ranges from 0.10 to 0.33 (mean $0.18{\times}10^{-3}SI\;unit$). The rocks of the artifacts are hard to find in the Gongju area. Large scaled out crop of hornblendite is not distributed, but found in many places that the form of dike. The lithology and occurrences indicate that the artifacts are made of plutonic rock rather than dike. Reddish brown and pale brown contaminants, are also distributed on the surface of the Stone Guardian and Memorial Tablets. The reddish brown color is due to Fe oxide, and the pale brown color occurs due to the elution of Ca. The reddish brown contaminants are influenced by the internal components of the rock and oxidation of burial iron accessories. In contrast, the pale brown contaminants are considered to have flown from the carbonate materials used in the Royal Tomb, with a little added Fe oxide. Physical and chemical deterioration operate intricately in the Stone Guardian and Memorial Tablets. Physical deterioration is extremely rare and chemical deterioration is stable except for a part of the Stone Guardian and the front of the Queen Stone Memorial Tablet.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.9 no.4
• /
• pp.177-186
• /
• 2005

The latest concrete structure has showed that the deterioration of durability has been increased by the damage from salt, carbonization, freezing & thawing and the others. Therefore, the measures for the concrete which has deteriorated durability have been taken. Among them, it has been often used that surface treatment which cuts off the deterioration factors of durability by protecting the surface of concrete. However, troubles such as fracture and rupture in the repair layer have been reported as time goes by due to the difference between the organic repair material like epoxy and concrete properties. Researchers have been developing the repair material which can cut off the deterioration factors of durability such as $CO_2$ gas, chloride ion and water by making the formation of concrete elaborate through the reaction with calcium ion when the surface improving agent is coated on the concrete. The main ingredient of that is inorganic substance which is the same as the concrete property. This study was evaluated the surface improving agent for permeability, watertightness, air-permeability, chemical resistance and elution resistance. As a result, it has been reported that the surface improving agent improves watertightness and air-permeability by penetration more than 10mm within concrete. Therefore, it is concluded that the surface improving agent developed in this research prevents deterioration of concrete durability when it is coated on the concrete structure.

• Journal of the Korea Concrete Institute
• /
• v.17 no.4 s.88
• /
• pp.489-498
• /
• 2005

Recently, the deterioration of concrete structures have been increased by the damage from salt, carbonization, freezing & thawing and the others. Therefore, the measures for the deterioration of concretes have been taken. Among them, it has been often used that surface treatment which cut off the deterioration factors of durability by protecting the surface of concrete. The water proof and repair materials for concrete mainly use organic materials such as epoxy, these materials excel in intial bonding force and resistance to chemical agents. But they cause difference in the modulus of elasticity and the rate of shrinkage and expansion of concrete, and thus result in such problems as scaling and spatting in the progress of time. Therefore in this study it develop the performance Improving agent of concrete surface that can block a deterioration cause such as $CO_2$ gas, chloride ion and water from the outside and enhance waterproofing ability by reinforcing the concrete surface when applying it to concrete structures.