• KIEAE Journal
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• v.2 no.3
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• pp.63-70
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• 2002

This study aims to provide the fundamental date of HUANGTO GUDUL for applying to current house heating system. It has been used as a traditional heating system in Korea for a long time and disappeared in the course of industrialization in Korea last a few decades and these days is tend to be widely adopted as house heating system. Even though it is known that the traditional heating system of HUANGTO GUDUL is good for ecological environment house and a kind of the natural friendly heating system for optimum residential heating environment, there are few systematic researches and analysed data of it. In order to analyse the characteristics of HUANGTO GUDUL, the existing materials of it's historical change was studied. And the architectural prospects of the use of GUDUL on the point of view of environmental ecology. The data of relationship between the mechanic properties and the workability of GUDUL materials and the environmental index such as the heating environment, relative humidity, and deodorization ratio and so on. And the heating effectiveness of GUDUL was compared with existing modem materials by experimental analysis. The results stated above can be grafted architecture and will be offered the optimum heating environment.

• Architectural research
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• v.11 no.1
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• pp.25-33
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• 2009

This study presents the testing of 15 hwangtoh-based cementless concrete mixes to explore the significance and limitations of the development of eco-friendly concrete without carbon dioxide emissions while maintaining various beneficial effects. Hwangtoh, which is a kind of kaolin, was incorporated with inorganic materials, such as calcium hydroxide, to produce a cement-less binder. The main variables investigated were the water-to-binder ratio and fine aggregate-to-total aggregate ratio to ascertain the reliable mixing design of hwangtoh-based cementless concrete. The variation of slump with elapsed time was recorded in fresh concrete specimens. Mechanical properties of hardened concrete were also measured: including compressive strength gain, splitting tensile strength, moduli of rupture and elasticity, stress-strain relationship, and bond resistance. In addition, mechanical properties of hwangtoh-based cement-less concrete were compared with those of ordinary portland cement (OPC) concrete and predictions obtained from the design equations specified in ACI 318-05 and CEB-FIP for OPC concrete, wherever possible. Test results show that the mechanical properties of hwangtoh-based concrete were significantly influenced by the water-to-binder ratio and to less extend by fine aggregate-to-total aggregate ratio. The moduli of rupture and elasticity of hwangtoh-based concrete were generally lower than those of OPC concrete. In addition, the stress-strain and bond stress-slip relationships measured from hwangtoh-based concrete showed little agreement with the design model specified in CEB-FIP. However, the measured moduli of rupture and elasticity, and bond strength were higher than those given in ACI 318-05 and CEB-FIP. Overall, the test results suggest that the hwangtoh-based concrete shows highly effective performance and great potential as an environmental-friendly building material.

• 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.

• Journal of the Mineralogical Society of Korea
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• v.29 no.4
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• pp.239-254
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• 2016

The Hwangto cave is a sea cave which is located near shore in the Taeha-ri, Ulleung Island, being composed of the reddish tuff wall rock, the topic of this study, and the trachyte ceiling rock. The chemical compositions of the red tuff layer are 49.81-63.63% of $SiO_2$, 13.05-24.91% of $Al_2O_3$, 2.67-5.82% of $Fe_2O_3$, 2.87-6.92% of $Na_2O$, 2.37-3.85% of $K_2O$, 0.55-0.81% of $TiO_2$, 0-0.53% of MnO, 0.39-1.75% of MgO, and 0.60-1.40% of CaO with a pH ranging from 4.5 to 8. The reddish tuff are composed of 23.7-39.4% of anorthoclase, 16.9-33.3% of sanidine, 15.8-26.1% of illite, 5.1-9.0% of hematite, 0-3.7% of goethite, 6.9-9.9% of titanium oxide, and 0.9-9.5% of halite in mineral composition. Although it only includes anorthoclase, sanidine, and illite as major minerals, there can be additional vitric minerals that could not detected by the XRD. The mineralogy and textures of the tuff layer indicate that it became reddish due to the formation of amorphous palagonite and the oxidation of the iron as a heat from the trachytic lava affects the underlying tuff to altered. This iron oxides are enriched in the palagonite, or form microcrystalline or amorphous minerals. We thus suggest that the red tuff layer was generated by the combination of the thermal oxidation involved in the trachytic lava flow on the tuff layer, the palagonitization of the matrix of the tuff, and the oxidation of iron-bearing minerals.

• Journal of Aquaculture
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• v.13 no.2
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• pp.169-174
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• 2000

Reproductive cycle of U. unicinctus was studied from September 1998 to August 1999, using gonadosomatic index (CSI) as an indicator. In November, the CSI values were maximum for male (6.2) and female (7.0), respectively; the values were lowest for them (1.0 and 0.5) during the successive february. Subsequently, they rapidly increased and attained peak by March-April. The values decreased again in both sexes and remained unchanged until August. The index increased in October to attain the peak by November. The CSI values clearly indicated that there are two spawning events in a year, namely the first one during April-May and the second one in December. Reproductive cycle was classified into the following successive stages: in female, multipication (January~February, June ~Setember), maturation (March~April, November), spent (May and December), degeneration and resting (June and January), and in male, multiplication January ~ february, June ~September), maturation (March~April, October~November), spent (May and December) and degeneration and resting (January and June). Histological observations revealed that oocytes in the ovary matured simultaneously in November and March. At the same time, the envelopes of matured testis became thinner than those in the early stage.

• 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 Conservation Science
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• v.36 no.6
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• pp.549-561
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• 2020

This study aimed to assess the performance and life of nine natural mineral dancheong pigments: Seokganju, Jinsa, Hwangto, Jahwang, Wunghwang, Seokrok, Noerok, Seokcheong, and Baekto. The design of the accelerated weathering test considered the domestic climate characteristics and the location of Dancheong. Outdoor weathering tests were conducted at the Research Institute in Daejeon and the Sungnyemun Gate in Seoul to confirm the field reproducibility of the accelerated weathering test. Monitoring of the physical changes in pigments through accelerated and outdoor weathering tests are based on ultraviolet exposure dose. Despite small cracks at the beginning of the tests, the monitoring showed that Seokganju and Baekto had no marked physical changes, but the surface cracks of Jinsa and Seorok continue to expand. Hwangto and Noerok were marked with water or were resin stained, and the particles of Jahwang, Wunghwang, and Seokcheong had lost their luster. Despite the absolute difference in color change in each test, the final chromaticity change patterns of pigments were similar in that the color difference between Baekto and Noerok was below five, and Jina was above 28. The physical and surface color pigment changes were more concentrated in outdoor weathering tests than in accelerated tests, and the Seoul site was more intense than the Daejeon site. This is because outdoor weathering tests are exposed to severe variations of temperature and moisture or deposition of dust particles and, in the case of Seoul, the site is more exposed to the external environment than the Daejeon site.

• Journal of Conservation Science
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• v.32 no.3
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• pp.403-416
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• 2016

Mineral composition and content of 22 Korean Dancheong pigment products were obtained by Rietveld quantitative analysis. Jubosa, Hwang, Seokrok, Seokcheong and Hobun consist of pure cinnabar, orpiment, malachite, azurite and calcite (or aragonite), respectively. Whereas Seokganju, Hwangto, Noerok, Lapis lazuli, Baekto and Cockie hobun mainly consist of hematite, goethite, celadonite, lazurite, kaolin mineral and portlandite, respectively. And they all consist of soil minerals (quartz, feldspar, sericite and vermiculite) and filler minerals in the industry field (calcite, gypsum and anhydrite) at a different content. Quantitative XRD proved more useful method to determined exact mineral composition and content than chemical or microscopical data. If this method utilize for specification of natural pigment product, it is considered to be applicable in restoration technology and conservation science field.

• Journal of the Korean Wood Science and Technology
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• v.37 no.1
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• pp.12-18
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• 2009

This study was attempted to investigate indoor air quality of a wooden house. Emission characteristics of carbonyl compounds from indoors whose interiors were finished using ecofriendly materials were detected. From the results of the examination, the carbonyl compounds mostly consisted of formaldehyde, acetaldehyde, and hexaldehyde. Especially, formaldehyde accounted for the largest portion of the compounds at 25.6~30.5%. All the rooms except for R2-2 contained formaldehyde less than criteria of indoor air quality of newly-constructed houses. In addition, all the rooms except for room R1-3, contained acetaldehyde more than the level of $48{\mu}g/m^3$ recommended by Japan's Ministry of Health, Labour and Welfare. As a results of the different wall covering, the room R1-1 of Hwangto emitted relatively higher levels of carbonyl compounds than the room R2-1 of phytoncide. In addition, the room R2-2 of the bamboo charcoal panels emitted more carbonyl compounds than the room R1-2. The living room R1-3 of Japanese cypress (Cryptomeria Japonica) emitted lower levels of carbonyl compounds than other rooms.