• Korean Chemical Engineering Research
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• 제51권4호
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• pp.513-517
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• 2013

This study focused on the synthesis of $Nb_xSrTi_{1-x}O_3$ photocatalysts which partially inserted Nb ions with excellent ability of fluorescence into the perovskite structured $SrTiO_3$ frameworks and their photocatalytic hydrogen productions from methanol/water splitting corresponding to the molar ratios of Ti and Nb. The characteristics of the synthesized $SrTiO_3$ and $Nb_xSrTi_{1-x}O_3$ powders were analyzed by X-ray diffraction (XRD), energy dispersive X-ray spectrometer (EDS), and UV-Visible spectrometer. The hydrogen evolution from methanol/water photo-splitting was enhanced over $Nb_{0.05}SrTi_{0.95}O_3$ compared to those over $SrTiO_3$ and another $Nb_xSrTi_{1-x}O_3$; 4.9 mL of hydrogen gases was collected after 8 h when 0.5g of $Nb_{0.05}SrTi_{0.95}O_3$ catalyst was used in pH 10.

• Resources Recycling
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• 제24권2호
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• pp.3-12
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• 2015

We researched characteristics of heat recovery rate and fouling according to structures and materials in heat exchangers like water preheater and air preheater. Economizer and air preheater have used in thermal electric power plant. we made small incinerator and heat exchangers to carry out simulated experiment. We observed fouling formation and change of heat recovery rate, combusting powdered coal for 24 hr. In economizer, fin tube type had the largest amount of fouling formation, followed by tube line type > pipe type > auto washing type according to structures. As heat recovery rate, fin tube showed highest recovery rate, followed by auto washing type > pipe type > tube line type. In air preheater, fin tube type had the largest amount of fouling formation, followed by fin plate type > pipe type > pipe type coated by teflon > pipe type coated by ceramic according to structures. And then, heat recovery rate showed the same oder.

• Resources Recycling
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• 제27권2호
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• pp.38-47
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• 2018

Integrated gasification combined cycle (IGCC) is a next generation energy production technology that converts coal into syngas with enhanced power generation efficiency and environmental performance. IGCC produces almost coal gasification slag as the solid by-product. IGCC slag is generated about 140,000 tons for a year although recycling of it is still in the early stages. We evaluated the potential of IGCC slag which is generated from a pilot plant in South Korea as an alkali-activated cement. Samples which were activated with the combined activator of sodium silicate solution and caustic soda had an average compressive strength of 4.5 MPa, showing expansion. Expansion of the alkali-activated slag was presumed to be caused by free CaO in the slag, although it was not detected by the ethylene glycol method. Samples that were activated with the combined activator of sodium aluminate and caustic soda had an average compressive strength of 10 MPa. Hydroxy sodalite and $C_3AH_6$ were found to be the new crystalline phases. IGCC slag can be used as an alkali-activated material, but the strength performance should be improved with proper mix design approach to calculate optimum proportions which can alleviate the expansion issue at the same time.

• Journal of the Korean Dietetic Association
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• 제10권1호
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• pp.13-24
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• 2004

This study was designed to examine fast food consumption, nutritional knowledge, food behavior and dietary intake of university students and to investigate if there were differences in these variables by fast food consumption. The questionnaire was administered to university students in Daejeon. Data(n=269) was analyzed using $x^2$-test and analysis of variance. Subjects were mostly female(62%) and freshmen or sophomores(86%). Based on the frequency of fast food consumption, subjects were categorized into non-users(27.9%), users(<2 times/week, 42%) and frequent users($\geq$2 times/week, 30.1%). Those who used fast foods(n=194) consumed the foods 7.5 times per month, on the average. Subjects scored 15.6 out of 20 on a nutritional knowledge scale, showing the moderate level of knowledge. When examined by fast food use, the nutritional knowledge score was 15.5 for non-users, 16.1 for users, and 15.0 for frequent-users(p<0.05). Only two items, regarding 'fat type(animal, plant) and health' and 'importance of having breakfast', were significantly different by fast food consumption, with user group and non-users scoring higher than frequent-users(p<0.05). Food behaviors, measured by 20 items, were not desirable, with mean scores of 51.5(possible score: 20-100). Subjects showed problems in eating meals regularly, eating a variety of foods, eating breakfast, and consumption of some food groups(vegetables, fruits, and proteins). Fast food non-users showed more desirable food behaviors than users or frequent-users, such as having processed foods (p<0.001) and eating-out less frequently(p<0.01). Dietary intake data showed that some nutrient intakes, including energy, calcium, iron, zinc and folic acid were less than 75% of the RDA. Index of nutritional quality(INQ) was adequate except for calcium and zinc. Compared to non-users or user group, frequent-users of fast foods consumed higher amounts of lipids(p<0.05), and had lower INQ for calcium(p<0.01). This study described the status of fast food consumption, nutritional knowledge, food behavior of university students, and provided some baseline data for planning nutrition education for university students.

• Journal of Bio-Environment Control
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• 제29권2호
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• pp.105-109
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• 2020

This study was conducted to the improvement of solar light-based artificial light supply system and effect of lettuce cultivation. The artificial light supply system was consisted of units such as light source, power, system measurement and controller. The light source supply was composed of a solar transmitter and an LED lamp. The power supply consisted of an leakage breaker, SMPS, LED controller and relay. The solar transmitter was made of a quartz optical fiber with optimal light transmission. Artificial light used white lamp among LEDs. System measurement and control consisted of touch screen, Zigbee communication module and light quantity sensor. The results of test confirmed that the LED light is automatically activated when the intensity measured by the light intensity sensor is 200 μmolm^-2s^-1 or less. Moreover, the leaf length, root length, chlorophyll content and root fresh weight of optical fiber treatment was hight than LED lamp treatment. Therefore, it can be inferred that the energy-saving solar light collector device can be effective in the indoor lettuce production. However, the use of LED lamp is also recommended to assure the availability of sufficient sunlight in cloudy and rainy days.

• Journal of Korean Society of Coastal and Ocean Engineers
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• 제28권4호
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• pp.177-190
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• 2016

In case of the seabed around and under gravity structures such as submerged breakwater is exposed to a large wave action long period, the excess pore pressure will be generated significantly due to pore volume change associated with rearrangement soil grains. This effect will lead a seabed liquefaction around and under structures as a result from decrease in the effective stress. Under the seabed liquefaction occurred and developed, the possibility of structure failure will be increased eventually. Lee et al.(2016) studied for regular waves, and this study considered for irregular waves with the same numerical analysis method used for regular waves. Under the condition of the irregular wave field, the time and spatial series of the deformation of submerged breakwater, the pore water pressure (oscillatory and residual components) and pore water pressure ratio in the seabed were estimated and their results were compared with those of the regular wave field to evaluate the liquefaction potential on the seabed quantitatively. Although present results are based on a limited number of numerical simulations, one of the study's most important findings is that a more safe design can be obtainable when analyzing case with a regular wave condition corresponding to a significant wave of irregular wave.

• Clean Technology
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• 제22권2호
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• pp.96-105
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• 2016

VOCs emissions from industries cause the air pollution and odor. In the industrial facilities, the existing odor treatment techniques have limits and problems. In this study, the optimum essential oil and metal oxide selected by screening test. lavender oil, cypress oil and TiO₂ were determined by deodorant materials and those were blended by 5%, 45%, 10%, respectively. In addition, the result of batch type experiments depending on the dilution rate, injection, rate, temperature showed that the optimum condition of deodorant is 6 mL of injection rate, and 200 times of dilution rate and the removal efficiency increased in proportion with temperature. In addition, the activation energy was calculated from the rate equation, which appeared in the 3-4 times lower than conventional deodorants.

• Journal of Sasang Constitutional Medicine
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• 제10권2호
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• pp.163-180
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• 1998

In 1492 year, the corn originated in America continent had spread all over the world after spreading into Europe by Columbus. Since the Corn had a similar shape with adlai's one (Yulmoo(율무)), it had been written by the different name of adlai (Yulmoo) at the "訓蒙字會(Hun-mong-ja-hoe)(1527)". Therefore we should consider "Hun-mong-ja-hoe" is the first record of the corn and it is a significant historic record in the civilization exchange between the Orient and the Occident that this record has the only difference of around 30 years later after the spreading corn to Europe. However, this is on the assumption that it is correct for a scholar of Korean literature to persist in that '叡山本' of "Hun-mong-ja-hoe" could be considered as the first edition. The corn had been once classified as a same kind of the Chinese millet because the people had been recognized the corn as a similar group of the Chinese millet and the Indian millet. The Chinese millet contains a summer vigor and becomes as an ingredient of alcoholic drink. And we can find out that $C_4$ type plant (such as corn, Chinese millet, Indian millet, foxtail millet) mostly have a tendency to belong to the food for "Taeumin(太陰人)", because of its high energy efficiency, a flourishing absorption of fertilizing and a strong emission power. The fried corn with a strong summer vigor and a raised feature has a good effect to the treatment of the teethridge disease. And the tea of corn with an warm feature, thanks to its functions of making the stomach and intestines comfortably as well as urination, is a proper food for the 'Taeumin" who is apt to overeat themselves.

• Journal of the Korea Concrete Institute
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• 제17권4호
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• pp.499-504
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• 2005

Polymer concrete shows excellent mechanical properties and chemical resistance compared with conventional normal cement concrete. The polymer concrete Is drawing a strong interest as high-performance materials in the construction industry Resins using recycled PET offer the possibility of a lower source cost of materials for making useful polymer concrete products. Also the recycling of PET in polymer concrete would help solve some of the solid waste problems Posed by plastics and save energy. An objective of this paper is to estimate the damage of sulfuric acid, through investigating recycled PET polymer concrete, immersed at sulfuric acid solution for 84 days. As a result of testing, recycled PET PC, used $CaCO_3$ as filler, makes a problem of appearance and strength if they are exposed for long term at corrosion environment. On the other hand, recycled PET PC, used fly-ash as filler, had less effect on decrease in weight and strength. Recycled PET PC is excellent chemical resistance, resulting in the role of unsaturated polyester resin which consists of polymer chain structure accomplishes bond of aggregates and filler strongly. Also, recycled PET PC, used fly-ash as filler, is stronger resistance of sulfuric acid corrosion than $CaCO_3$, because it is composed of $SiO_2$ and very strong glassy crystal structure. Therefore, recycled PET PC, used fly-ash as filler, is available under corrosion circumstances like sewer pipe or waste disposal plant.

• Journal of the Korean Society of Environmental Restoration Technology
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• 제7권4호
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• pp.8-16
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• 2004

The industrialization of central Europe more than 100 ago marked the beginning of densely concentrated buildings in quickly growing cities. A cheap type of roofing material of that time was tar. But it was dangerous because it was high inflammable. Then some roofer had a splendid idea. They used sandy material as a final layer atop the impermeable tar layer. These roofs were much more fire resistant than the typical roofs. In this sandy layer some plant species began to grow spontaneously. This was the beginning of the green roof history of modern Europe. A number of these green roofs survived both world wars. In the early 80's in Berlin alone, 50 such buildings existed and they continued to be waterproof until the present day. Since the 1992 Earth Summit of 1992 in Rio de Janeiro(http://www.johannesburgsummit.org/html/basic_info/unced.html) the term "sustainable development" became of central interest of urban designers. In city regions green roofs had become synonymous with this term. With a small investment, long-lasting roofs can be created. Further back in history, more exciting examples of green roofs can be found. The hanging gardens of antiquity are well-known. There are also green roofs built as insulation against cold and heat all over the world. For over 20 years, roof greening in central Europe has been closely examined for various reasons. Roof greening touches several different disciplines. Of primary interest is the durability of the roofs. But ecologists are also interested in green roofs, for instance in biodiversity research. The beneficial effect of greening on water proofing was also proven. For some time, the issue of fire protection was investigated. According to tests, green roofs received a harsh careful rating. Their fire protective property is considered similar to that of tile roofs. Another recent impulse for the green roof movement in Germany has come from the evident improvement of storm water retention and the reduced burden on the sewer system. The question of whether and how much energy green roofs can save has become an urgent question. The state of the research and also various open questions from a central European point of view will be discussed in the context of international collaboration. Apart from academic considerations, those who involve themselves in this issue take a predominantly positive view of the numerous existing green roofs in Germany. In some cities, green roofs are the typical construction technique for new buildings. A few outstanding examples will conclude this review. In Germany, about 20 companies, some of which operate internationally, specialize in green roof consulting. Learning from each other in an open-ended way with respect to different construction techniques and applications in various climatic regions can only be accomplished through such international collaboration as is taking place here.