• Economic and Environmental Geology
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• v.37 no.1
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• pp.143-151
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• 2004

This study focused on examining the possibility of recycling mine solid waste as environmental materials, especially for porous media. Basic properties including mineralogical compositions, chemical compositions, and particle size distribution of the tailings from the Sangdong W mine were checked. The mineralogical and chemical compositions of the tailings samples were not much different in depth. According to Korean Standard Leaching Test for Wastes(KSLT), concentrations of heavy metals leached from the tailings were below the standard values. As a result of particle size analysis, the median diameter (d$_{50}$) of the tailings was in the range of 10 to 30 ${\mu}{\textrm}{m}$. The stable tailings slurry made up of 3 ${\mu}{\textrm}{m}$ in d$_{50}$ was prepared using Attrition Mill. The milling condition was 40 vol% in slurry concentration, 700 rpm in stirring speed, and 1 hour in milling time. PEI was added as dispersing agent. Concentrated slurry was extended to 3 times by foaming method. In the case of 3 times foamed slurry, the total and open porosity of ceramic supports sintered at 1,075$^{\circ}C$ for 90 minutes was about 80% and 72%, respectively. Pore size was in the range of 30∼350${\mu}{\textrm}{m}$. Therefore, the tailings could be recycled starting material for environmental materials such as macroporous ceramic support.

• 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 Korea Institute of Building Construction
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• v.11 no.2
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• pp.127-135
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• 2011

In this study, the engineering characteristics of outer wall insulation panels according to type of insulation materials, their combination, and the contents of insulation materials were tested. Vermiculate, ceramic bead, perlite and expanded polystyrene were used as insulation materials. Flexural strength and thermal conductivity depending on the insulation materials used were measured. It was found that the flow of fresh mortar significantly decreased with an increase in the contents of insulation materials. In terms of the effect of insulation materials on thermal conductivity, an increase in insulation materials resulted in a decrease of thermal conductivity. In particular, PL and EPS, when used together, have lower thermal conductivity than other materials. Regarding the flexural strength of the hardened mortar, the strength showed a tendency to gradually decrease according to the increase in contents of insulation materials, compared to that of the plain mortar. In terms of the flexural strength depending on various types of insulation materials and its combination, it was found that the flexural strength of cement mortar containing 3% of vermiculate(V)+ceramic bead(CB)+perlite(PL) was the highest among the specimens tested.

• Journal of Korea Association of Health Promotion
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• v.3 no.2
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• pp.199-218
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• 2005

이 연구는 우리나라 20세 이상 성인에서의 대사증후군 유병률을 파악하고 보건의식행태와 대사증후군간의 상관관계를 분석함으로써 대사증후군의 예방 및 치료를 위한 보건교육·건강증진 프로그램의 기초자료로 활용코자 시행되었다. 연구재료로 1998년 국민건강영양조사에 참여한 20세 이상 성인 24,469명 중 건강검진조사를 받았고 건강면접조사, 보건의식행태조사, 식생활조사에 응답한 7,854명의 조사결과를 활용하였으며, 2001년 미국에서 발포된 제 3차 콜레스테롤 관리지침(NCEP-ATP3)에서 제시된 대사증후군 진단기준 및 WH0 아시아/태평양지역 허리둘레를 기준으로 대사증후군 유병률을 분석하였다. 결과는 다음과 같다. 우리나라 20세이상 성인의 대사증후군 유병률은, NCEP-ATP3 기준에서 13.3%(남자 10.1%, 여자 16.0%), 아시아/태평양지역기준에서 19.8%(남자 16.7%, 여자 22.4%)로 아시아/태평양지역 기준에서, 남자보다는 여자에서 더 높았다. 대사증후군 진단항목 중복부비만, 저 HDL-콜레스테롤의 유병를은 여자에서, 고중성지방혈증, 공복시고혈당 유병률은 남자에서 더 높았고, 연령이 증가할수록 대사증후군의 유병률이 증가하였다. 또 대사증후근 진단할목의 보유경향은 ATP3진단기준에서 남자는 복부비만을 제외한 4개항목을 70%이상에서, 특히 고중성지방혈증은 95.0%에서 보유하였다 여자는 저HDL-콜레스테롤과 고중성지방혈증을 70%이상에서 보유하였다. 아시아/태평양 진단기준에서는 남자의 경우 고중성지방혈증을 88.0%에서, 여자의 경우 복부비만 및 저 HDL-콜레스테롤을 80%이상에서 보유하고 있었다. 대사증후군과 보건의식행태 간의 상관관계를 분석한 결과, 교육수준이 낮을수록, 결혼하지 않은 사람에 비해 결혼한 사람에서대사증후군 위험이 증가하였으며, BMI가 증가할수록 대사증후군 위험이 급격히 증가하였고, 고혈압·뇌졸중, 당뇨병 가족력이 있는 남자에서 대사증후군 위험이 증가하였다. 또 스스로 건강하지 않다고 생각하는 사람일수록 현재 흡연자의 PACK- YEAR가높을수록, 자주 술을 마실수록, )회 음주량이 많을수록, 과음빈도가 많을수록 대사증후근 위험이 증가하였으며, 알코올 의존 경향이 있는 경우에서도 유의한 결과를 보였다. 최근 1년간 체중이 감소 혹은 증가된 경우에서 유의한 결과를 보였으며, 체증감소정도가 클수록 대사증후군 위험이 증가하였다. 이상의 결과를 종합해 볼 때, 우리나라 성인의 대사증후군 유병률은 비교적 높으며 대사증후근의 발생에는 보건의식행태, 특히 음주 흡연비만 연령 교육수준 등이 밀접하게 관여한다고 할 수 있다. 그러나 앞으로 대사증후군의 예방을 위한 건강증진 프로그램의 기획 및 치료방침 수립을 위해서는 우리 나라대사증후군의 유병에 영향을 미치는 진단기준항목 및 관련요인의 상호 연관성, 우리나라에 적합한 진단기준 설정 등에 대한 지속적이고 깊이 있는 연구가 이루어져야 할 것이다.

• Journal of the Korean Wood Science and Technology
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• v.40 no.1
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• pp.19-25
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• 2012

The fire retardant bamboo charcoal (BC) boards were manufactured for interior building materials in this study, The BC boards were manufactured by mixing and pressing of the bamboo charcoal, expanded vermiculite, and inorganic binder. The combustion behaviors of the BC boards were investigated using a cone calorimeter at an incident heat flux of 50 kW/$m^2$. Three building materials (plywood, BC board of Japan, and gypsum board) were used to observe the burning behaviors of weight loss, total heat release rate, and maximum heat release rate. Surface test and toxicity evaluation of the BC board were also conducted. The weight loss of the BC board (12.0%) was lower than the nonflammable gypsum board (15.6%) after burning of 10 min. Total heat release of the BC was 3 MJ/$m^2$ (KS standard 8 MJ/$m^2$) and total heat release rate of the BC was 20 kW/$m^2$ (KS standard 200 kW/$m^2$). Therefore, the BC boards were adjustable for the third-grade flame retardant building materials. External appearance change and mouse toxicity were not found in the BC boards after the combustion test.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.36 no.2
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• pp.117-125
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• 2000

The waveform and spectrum analysis of Tursiops truncatus(bottlenose dolphin) sonar signals were carried out on the basis of data collected during the dolphin show at the aquarium of Cheju Pacificland from October 1998 to February 1999. When greeting to audience, the pulse width, peak frequency and spectrum level from the five dolphins'sonar signals were 3.0ms, 4.54kHz and 125.6dB, respectively. At the time of warm-up just before the show, their figures were 5.0㎳, 5.24kHz and 127.0dB, respectively. During the performance of dolphins, with singing, peak frequency ranged 3.28∼5.78kHz and spectrum level ranged 137.0∼142.0dB. With playing ring, pulse width, peak frequency and spectrum level were 7.0㎳, 2.54kHz and 135.9dB, and when playing the ball, the values were 9.0㎳, 2.78kHz and 135.2dB, respectively. The values determined from the five dolphins during jump-up out of water were : pulse width 2.0㎳, peak frequency 4.50kHz and spectrum level 126.8dB. When they responded to trainer's instructions, the values were 2.25㎳, 248kHz and 148.7dB, respectively, and greeting to audience, the peak frequency and spectrum level were 5.84kHz and 122.5dB. During swimming under water, peak frequency and spectrum level were determined to be 10.10kHz and 126.8dB. It was found that there exited close consistencies in pulse width, frequency distribution and spectrum level between whistle sounds and dolphin's sonar signals. Accordingly, the dolphins can be easily trained by using whistle sound based on the results obtained from the waveform and spectrum of the dolphin's sonar signals.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.36 no.3
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• pp.175-185
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• 2000

This paper described on a basic study to organize fishing vessel control system in order to control efficiently fishing vessel in Korean offshore. It was digitalized ARPA image on the fishing processing of a fleet of purse seiner in conducting fishing operation at Cheju offshore in Korea as a digital camera and then simulated by used VTMS. Futhermore, it was investigated on the application of FVTMS which can control efficiently fishing vessels in fishing ground. The results obtained were as follows ; (1) It was taken 16 minutes and 35 minutes to casting and hauling net in fishing processing respectively. The length of rope pulled by scout boat was 200m, tactical diameter in casting net was 340.8m, turning speed was 6kts as well. (2) The processing of casting and hauling net was moved to SW, NE as results of simulation when the current direction and speed set into NE, 2kts and SW, 2kts respectively. Such as these results suggest that can predict to control the fishing vessel previously with information of fishing ground, fishery and ship's maneuvering, etc. (3) The control range of VTMS radar used in simulation was about 16 miles. Although converting from a radar of the control vessel to another one, it was continuously acquired for the vector and the target data. The optimum control position could be determined by measuring and analyzing to distance and direction between the control vessel and the fleet of fishing vessel. (4) The FVTMS(fishing vessel traffic management services) model was suggested that fishing vessels received fishing conditions and safety navigation information can operate safely and efficiently.

• Resources Recycling
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• v.9 no.6
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• pp.36-44
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• 2000

Fly ash was composed of the unburned carbon and mineral particles. The former was able to attach on the bubbles, while the latter was not. Therefore, it was possible to separate the unburned carbon and the mineral from fly ash using the froth flotation process. This study was carried out to evaluate the separation efficiency as a function of the ny ash particle properties in the column flotation. Separation efficiency was analyzed for various size fraction of -38 fm,38~125 fm and 1125 W, and for various fly ash samples containing 7, 11, and 20 wt% unburned carbon. For the size fractions of -38 fm containing 7 wt% unburned carbon, separation efficiency was 86ft, whereas separation efficiency was found to be 74% for the size fraction of +125$\mu\textrm{m}$ containing 20 wt% unburned carbon. The results indicated that separation efficiency increased with the decrease in the particle size and the unburned carbon content of the fly ash.

• Journal of the Korean Wood Science and Technology
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• v.46 no.1
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• pp.73-84
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• 2018

Recently, the importance of flame retardation treatment technology has been emphasized due to the increase in urban fire accidents and fire damage incidents caused by building exterior materials. Particularly, in the utilization of wood-based building materials, the flame retarding treatment technology is more importantly evaluated. An Intumescent system is one of the non-halogen flame retardant treatment technologies and is a system that realizes flame retardancy through foaming and carbonization layer formation. To apply the Intumescent system, composite material was prepared by using Ethylene vinyl acetate (EVA) as a matrix. To enhance the flame retardant properties of the Intumescent system, a nano-clay was applied together. Composite materials with Intumescent system and nano - clay technology were processed into sheet - like test specimens, and then a new structure of cross laminated timber with improved flame retardant properties was fabricated. In the evaluation of combustion characteristics of composite materials using Intumescent system, it was confirmed that the maximum heat emission was reduced efficiently. Depending on the structure attached to the surface, the CLT had two stages of combustion. Also, it was confirmed that the maximum calorific value decreased significantly during the deep burning process. These characteristics are expected to have a delayed combustion diffusion effect in the combustion process of CLT. In order to improve the performance, the flame retardation treatment technique for the surface veneer and the optimization technique of the application of the composite material are required. It is expected that it will be possible to develop a CLT structure with improved fire characteristics.

• Journal of the Korean Recycled Construction Resources Institute
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• v.4 no.4
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• pp.388-395
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• 2016

This paper explores the photocatalytic sensitivity of cement mortar incorporated with recycled $TiO_2$ from waste water sludge. Basically, $TiO_2$ cluster sank down slowly to the bottom of cement mortar specimen before setting and hardening process. This leads the mismatch of $TiO_2$ concentration on the top and the bottom faces of a specimen. This poorly dispersed $TiO_2$-cement mortar naturally exhibits poor NOx removal efficiency especially on the top of cementitious structure. In architectural engineering application such as building or housing structures, one can simply filp over from the bottom so that more $TiO_2$ concentrated surface can be placed outward into the air. However, in highway pavement case, this could not be applicable due to in-situ installation of concrete pavement. Hence, the dispersion of $TiO_2$ cluster inside the cementitous material is getting important issue onto road construction application. To elaborate this issue, according to our results, silica fume, high-ranged water reducer, viscosity agent, blast furnace slag were not enhanced much of dispersion characteristics of $TiO_2$ cluster. The combination of foaming agent and accelerator of hardening with viscosity agent and small grain size of fine aggregate may help the dispersion of $TiO_2$ inside cementitious materials. Even though the enhanced dispersion were applied to the specimen, NOx removal efficiency doest not change much for the top surface of the specimen. This concurrently affected by the presence of tiny air voids and the dispersion of $TiO_2$ in that these voids could easily adsorbed NOx gas with the aid of large surface area.