• Journal of Korean Society of Environmental Engineers
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• v.35 no.11
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• pp.781-784
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• 2013

Ocean dumping of sewage sludge is banned. Therefore, it is needed to develop alternative treatment method. Sewage sludge and waste glass are used to prepare lightweight brick. Large amount of energy is consumed to prepare building material, because of its high preparation temperature, or above $1,200^{\circ}C$. We study to prepare lightweight brick, using sewage sludge and waste glass as raw materials in this research. Lightweight brick was made at low temperature of below $800^{\circ}C$ to reduce $CO_2$ emission by geopolymer technique. Calcination temperature, mixing ratio of sewage sludge/waste glass and water glass/water were discussed to evaluate their effect on the brick prepared. In this study, the optimal conditions for preparing bricks was $750^{\circ}C$ of firing temperature, 1.5 of mixing ratio for water glass/water and 10 : 90 wt% of sewage sludge/waste glass. At this condition, compressive strength and specific gravity of brick prepared were 5.1 MPa and 0.46, respectively. These values satisfy the criteria on a lightweight brick.

• Journal of the Korean Society for Marine Environment & Energy
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• v.4 no.2
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• pp.43-51
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• 2001

Now our ocean environment pollution is very serious. Its harm hinders in marine breeding and the safe navigation of ships at the coast. We have used an assembly system for a measure taken against environment pollution like this. But, here are some problems awaiting solution. First, most of combustible materials among ocean waste are high polymer, so it is necessary some special equipment to incinerate them. In the process we can't overlook air pollution by exhaust gas. Also, when we reclaim these wastes, we remember that they can't be decomposed naturally and leaking water may pollute soil. Thus now a days new treatment method has been developed, it recycles and doesn't product secondary pollution materials by recovering oil from pyrolysis. For it, this study investigated chemicalㆍphysical properties of wastes. And it found condition of recovering the most oil. Also it probed that the variation of temperature raising speed affects the weight reduction characteristics of wastes. Also, while studying recovered oil by waste pyrolysis and the rate of non-condensing gas in accordance with the variation of temperature raising speed. Finally we had confidence the development of pyrolysis oil recovery would succeed because we carried out evaluation at an economic point of view about it.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.8
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• pp.248-255
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• 2020

The effects of the coating thickness on the thermal durability and thermal stability of thermal barrier coatings (TBCs) with a gradient coating thickness were investigated using a flame thermal fatigue (FTF) test and thermal shock (TS) test. The bond and topcoats were deposited on the Ni-based super-alloy (GTD-111) using an air plasma spray (APS) method with Ni-Cr based MCrAlY feedstock powder and yttria-stabilized zirconia (YSZ), respectively. After the FTF test at 1100 ℃ for 1429 cycles, the bond coat was oxidized partially and the thermally grown oxide (TGO) layer was observed at the interface between the topcoat and bond coat. On the other hand, the interface microstructure of each part in the TBC specimen showed a good condition without cracking or delamination. As a result of the TS test at 1100 ℃, the TBC with gradient coating thickness was initially delaminated at a thin part of the coating layer after 37 cycles, and the TBC was delaminated by more than 50% after 98 cycles. The TBCs of the thin part showed more oxidation of the bond coat with the delamination of topcoat than the thick part. The thick part of the TBC thickness showed good thermal stability and oxidation resistance of the bond coat due to the increased thermal barrier effect.

• Journal of the Korean Applied Science and Technology
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• v.36 no.4
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• pp.1188-1197
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• 2019

Exposure to stress can lead to sympathetic hyperactivity, which include a systemic disease with lesions in a broad spectrum of organs and a psychiatric condition. The purpose aimed to evaluate the effect of the korea ginger essential oil on stress hormone and brain tissue response in chronic mild stress-induced rats model of sympathetic hyperactivity. Evaluation method carried out cytotoxicity assessment and component analysis, what observe the effects based on serum biomarker and histopathological analysis of brain tissue. As this time, the korea ginger essential oil was treatment at doses of 100 nl/㎖ for 2 weeks after make a chronic mild stress-induced rats model of sympathetic hyperactivity. As a result, the korea ginger essential oil was not toxic at less than 100 nl/㎖, contents of 6-gingerol was 345 ppm. Compared to the control rats, the korea ginger essential oil treatments significantly reduced the serum concentrations of stress hormone (i.e., ACTH, corticosterone, melatonin). Furthermore, The korea ginger essential oil treatments effectively preserved the TH-immune response was occasionally interrupted in the ventral tegmental area (VTA) and the substantia nigra pars compacta (SNpc). The results indicate that the korea ginger essential oil improved sympathetic hyperactivity. Thus, the korea ginger may be a novel material of aroma oils for the management of sympathetic hyperactivity.

• Journal of the Mineralogical Society of Korea
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• v.32 no.4
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• pp.287-301
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• 2019

Preservation of the original form is the principle for conservation, management and utilization of cultural heritages. Thus, non-destructive analysis of these samples are important field of the conservation science. In this study, examined the applicability of nondestructive surface X-ray diffraction analysis (ND-XRD) for cultural heritage by materials (rock specimen, jade stone, pigment painted specimen, earthen artifact, metal artifact). In result, all type of sample is recorded suitable X-ray diffraction patterns for identifying mineral composition in case of surface condition with adequate particle size and arrangement. And diffraction pattern is reflected surface information than matrix. Therefore, ND-XRD is thought to be applicable not only mineral identification but also interpretation of manufacturing technique and alteration trend about layered sample (in horizontally or vertically). Whereas some exceptional diffraction patterns were recorded due to overlapping information on specific crystal planes. It caused by skip the sample treatment (powdering and randomly orientation). It could be advantageously used for mineral identification, such as preferred orientation of clay minerals. In contrast, irregular diffraction pattern caused by single crystalline effect is required careful evaluation.

• Korean Journal of Agricultural Science
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• v.29 no.2
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• pp.53-66
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• 2002

This study was performed to evaluation the consolidation behavior of agricultural reservoir in the very soft ground. The final settlement prediction methods by Terzaghi, Hyperbolic and Asaoka methods were used to compare with the degree of consolidation estimated by exess pore water pressure. The dissipated excess pore water pressure during embankment construction and peak excess pore water pressure on the completed embankment were suggested for the estimation of the degree of consolidation. It was concluded that the degree of consolidation estimated from dissipated excess pore water pressure was more reliable than that from the peak excess pore water pressure. The stability methods for agricultural reservoir was used to compare and analyze with various condition by limit equilibrium method.

• Journal of Environmental Policy
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• v.3 no.2
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• pp.113-137
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• 2004

The objective of this study is to introduce the definitions and classification methods of wastes in international agreements and legislations, examine the concept of wastes and their classification systems in Korea, and finally analyze and compare the concept of wastes in different countries for finding better solutions and suggestions. The study summarizes the concept of wastes as introduced in the Basel Convention, OECD, EU, US, and UK. First, each of the member countries adapt to the same concepts of wastes as defined in their international agreements; second, the intention of the wastes holder and the conditions of the wastes are considered at the same time when defining the concepts. Upon close examination of the classification of wastes systems as introduced in the Basel Convention, OECD, EU, US, and UK, the wastes are classified into toxic and non-toxic wastes according to the existence of poisonous substances. Therefore, it is classified as a toxic waste when any toxic substance on its list is included in the waste, while others are considered as a non-toxic waste if they don't contain poisonous substances. Secondly, in the UK, the matter of toxic or non-toxic wastes are classified, not according to the existence of the poisonous substances, but based on the generation of sources. In Korea, the concepts of wastes are divided into the two categories - a concept as defined in actual legislations and a concept in its translation. The Korean classification of the wastes include Wastes Management Act, amended in 1995, which stipulates that toxic substances should be managed in a special way as the designated wastes. It appears that the Act utilizes the classification method that classifies the wastes according to the existence of poisonous substance. Korea's concepts of wastes should be changed after recognition of the concepts in international agreement (Basel Convention, EU) and other foreign laws(US, UK) that consider subjective and objective standards at the same time when they define the concepts. Also, the development of technology in recycling and reuse of the wastes can remove the current absolute notion of the wastes so that it also should not be passed over. Also, because a classification structure of wastes has a close relationship with a disposal structure, its classification system should be fixed gradually to come up with the development of wastes disposal technology and its policy.

• Journal of the Korean Geotechnical Society
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• v.19 no.6
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• pp.217-225
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• 2003

An experimental study was conducted to evaluate the smeared effect due to mandrel penetration into soft ground for a vertical drain installation. Laboratory tests were performed to investigate the formation of a smear zone, the variations of strength, and the consolidation characteristics in the disturbed zone using two types(CL at Yangsan site and OH at Pohang site) of soft clayey soils. The smear zone effect was evaluated focusing on mandrel shape, mandrel size, penetration speed, and ground condition. Based on laboratory test results, the diameter of the smear zone$(d_s)$ ranged from 3.08 and 3.92 times that of mandrel$(d_m)$. It was also found that the $(d_s/d_m)$ value of the circular shape of the mandrel is smaller than those of square and rectangular shapes. The value of $(d_s/d_m)$ decreased with larger mandrel size, lower penetration speed in the CL soil, and higher penetration speed in the OH soil. However, natural water content was minimally affected by $(d_s/d_m)$. Respectively, the coefficients of horizontal consolidation$(C_{hs})$ and horizontal Permeability$(K_s)$ of smear zone ranged from 0.81 to 0.87 times, and 0.73 to 0.83 times those of the undisturbed zone. Based on this study, the values of $C_{hs}, K_s$ and unconfined compressive strength$(q_{us})$ in the smear zone were the lowest at close vicinity of the mandrel and increased linearly with distance from the mandrel. Further, the $(q_{us})$ varied from 0.5 to 0.9 times that of the undisturbed zone strength.

• Journal of the Korea Concrete Institute
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• v.15 no.4
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• pp.541-548
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• 2003

This study is to investigate the temperature curve and development of compressive strength due to the curing conditions and to evaluate the optimum curing condition of test specimens showing the same development of strength to that of real structures in cold weather. The results of temperature curve with curing conditions in mock-up tests showed the trend of decrease plain concrete with insulation form, plain concrete with heating, concrete with accelerator for freeze protection, and control concrete in turn. The strength development of plain concrete of inside and outside of shelter showed the very slow strength gains due to early freezing, but that of concrete with accelerator for freeze protection showed the gradual increase of strength with time. From this, it is clear that accelerator for freeze protection has the effects of reducing the freezing temperature and accelerating the hardening under low temperature. Strength test results of small specimens embedded in members and located in insulation boxes at the site are similar to that of cores drilled from the members at the same ages, thus it is clear that these curing methods are effective for evaluation in-place concrete strength.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.5 no.1
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• pp.113-127
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• 2010

The purpose of this study is to develop and to verify an effect of a group counselling program for children who are in need of improving social skills and relationships. In order to meet this goal, the study procedure was employed as follows: First, the literature review of studies on childrens in social welfare institutions was implemented. Second, to analyze need of staffs in facilities and to specify the present condition of children, 100 staffs were participated in basic investigation. The result of investigation revealed that social skill development programs should be held in form of total 11~12 sessions once or twice in a week, with 50~60 minutes per session. Third, based on the literature review and current situation investigation results, a program for improving social skills and competencies of children was developed. To verify the program, two groups composed of elementary children who are fourth grade to sixth grade were organized. The groups were a experimental group which was provided with a group counselling program and a control group with no program. The program was composed of twelve sessions throughout six weeks, and the subjects took social skill test after taking the program to verify educational effects. T-test were implemented to analyze difference of the test results of two groups statistically. As a result of a research, following major two findings were specified: (1) experimental group showed significant difference in the score of self-assertion, cooperation, and self-control, which indicates that the program was effective for social skill improvement: (2) according to the test result, the self-assertion, cooperation, and self-control skills were clearly improved. In conclusion, the program turned out to be an effective and a positive educational device to enhance social skills of the children. The program developing model were suggested to improve social skills of children in the state of family devision based on the study findings. The follow-up future studies should elaborate program models for various-aged children and for children with various learning styles. Furthermore, qualitative study method should be employed which can specify social attitude change of children.