• Journal of Environmental Impact Assessment
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• v.28 no.6
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• pp.592-603
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• 2019

This study is about the implementation of low energy sewage management technology through effective control of blower which consumes the most energy in sewage treatment. In calculating the amount of oxygen required for microorganisms, unlike the existing method using the operating index in the bioreactor or TMS data in the discharge port, the CODcr and NH₄⁺-N concentration changes in sewage flowing into the sewage treatment plant were detected in advance before entering the bioreactor and the amount of air was controlled based on this. The pre-sensing was found to have a high correlation compared with conventional products. As a result of blower control, it was possible to save about 9.9% energy more than the manual control. Consequently, this study suggested the possibility of blower's real-time control combined with pre-sensing technology. Also, it is expected that the low energy sewage treatment can be applied to sewage treatment facilities dependent on operation by manpower, and it will contribute to the reduction of greenhouse gas emissions.

• Korean Journal of Environmental Agriculture
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• v.16 no.4
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• pp.285-290
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• 1997

This study was conducted to develop labor-saving pesticide-fertilizer mixed formulation through a single application of mixed formulation of an insecticide imidacloprid coated on a slow release urea. The release of both total nitrogen and imidacloprid into water was delayed with increasing adhesive.Imidacloprid was released out 95% within 24 hours, whereas total nitrogen released in mixed formulation until 40 days was released less extent by increasing adhesive. There was no difference between pesticide-fertilizer mixed formulation and coated urea thereafter. The content of $NH_4-N$ in the soil treated with pesticide and urea seperating was higher until 10 days but gradually decreased compare to that of pesticide-fertilizer mixed formulation or coated urea. The population density of nitrate reducing bacteria and denitrifying bacteria in soil after treatment were lower in the pesticide-fertilizer mixed formulation and coated urea than those of pesticide and urea separate treatment. The residue of imidacloprid in soil was slightly higher in the treatment of pesticide alone than the pesticide-fertilizer mixed formulation and pesticide and urea seperating treatment. The population and control efficacy of small brown planthopper, Laodelphax striatellus, were not significance different among treatments.

• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.4
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• pp.642-649
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• 2021

Energy saving standard for buildings are strengthened, the application of exterior insulation finishing system and thickness of insulation materials are increasing. Most buildings with exterior insulation finishing system is applied organic insulating material. Organic insulating material have workability, economic feasibility, reduction in construction cost, and excellent thermal insulation performance. However, Organic insulating material is very vulnerable to heat, so when a fire occurs, rapid fire spread and toxic gas are generated, causing many casualties. Inorganic insulating material can be non-combustible performance, but it is heavy and has low thermal insulation performance. Mineral wool has higher thermal insulation performance than other types of inorganic insulating material, but mineral wool is disadvantageous to workability and vulnerable to moisture. Glass bubble are highly resistant to water and chemically stable substances. In addition, the density of the glass bubble is very low and the particles are spherical, fluidity is improved by the ball bearing effect. Glass bubbles can be used with cement-based ino rganic insulating material to impro ve the weight and thermal insulatio n perfo rmance o f cement-based inorganic insulation. This study produced a inorganic insulating materials were manufactured using cement-based materials and glass bubble. In order to evaluate the insulation performance and flame retardant performance of cement-based super light-weight inorganic insulating materials using with glass bubble, insulation performance or flame retardant and non-combustible performance were evaluated after manufacturing insulating materials using micro cement and two types of glass bubbles. From the test result, Increasing the mixing ratio of glass bubbles improved the insulation performance of cement-based super light-weight inorganic insulating materials, and when the mixing ratio of glass bubbles was 10%, it sho wed sufficient flame retardant and no n-co mbustible perfo rmance.

• Fire Science and Engineering
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• v.33 no.2
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• pp.124-131
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• 2019

When a fire occurs in a road tunnel, it is likely to develop into a major disaster because of its sealed structural characteristics. Because of this, a range of disaster prevention facilities should be installed, and they should show their appropriate functions in fire prevention and response. In addition, the installation of essential disaster prevention facilities is missing due to the lack of considering an extension of continuous tunnels and soundproof tunnels. For these reasons, it was judged that an amendment to the law would be necessary. Therefore, this paper reviewed the changes in domestic laws related to the disaster prevention facilities of road tunnels, and the results of the study on the parts that need to be revised in the fire-related laws through a comparative analysis between laws are as follows. First, consecutive tunnels should consider the sum of the extensions of the individual tunnels and ensure that the soundproof tunnels are included in the category of tunnels in the law. In this way, the necessary disaster prevention facilities should be installed. Second, it is necessary to secure a legal justification for installing disaster prevention facilities in tunnels. Therefore, it is essential that water mist fire extinguishing system facilities, emergency broadcasting facilities, and leading lights, which are excluded from installation in tunnels, are specified in the Fire-related laws. Third, to specify in the law that air respirators must be provided in the tunnel is necessary from the viewpoint of the field response. Accordingly, it will make a great contribution to the fire-fighting activities and the life-saving efforts by fire-fighters.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.7
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• pp.820-828
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• 2017

Tools and equipment that can provide buoyancy for a drowning person are important for saving lives. The purpose of this study was to estimate the minimum amount of gas needed and the buoyancy value in newton units required to generate the minimum buoyancy determined to be sufficient for keeping the head of a drowning person above the water's surface to allow for respiration for at least 1 minute. A buoyancy experiment was carried out with a long rubber balloon injected with carbon dioxide gas, and a buoyancy measurement experiment was performed on six college students. The degree of buoyancy was measured using a 5-point scale, and the statistical value of the measured data was analyzed to estimate minimum buoyancy. As a result, 8 grams of carbon dioxide were determined to satisfy minimum buoyancy conditions with a confidence level of 72%, and buoyancy was calculated to be 44.66 newtons. 12 grams of carbon dioxide met the minimum buoyancy conditions with a confidence level of 100%, and buoyancy was calculated to be 66.99 newtons. This study is expected to contribute to the development of low cost, easy-to-carry minimum buoyancy aids.

• Journal of the Korean Society of Food Culture
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• v.22 no.3
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• pp.342-352
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• 2007

We investigated the intake trends of street foods for middle school, high school and colleges students through the survey study. In addition, the factors affecting the students' consumption of street foods and their perception toward hygiene status of street vendor were studied. The levels of total aerobic bacteria, coliform groups and enterobacteriaceae in Kimbab, eomuk, and eomuk-kukmul were counted using 3M petrifilms. More than ninety seven % of the respondents had experienced street foods. All the respondents ate street foods 1 to 5 times a month. Forty percent of the respondent stated that 'good taste' and 'time-saving convenience' were their reason for eating the street foods. Their favorite foods were ddokbokgi and various fried foods. All the students responded that frying oil, drinking water, and soy sauce as well as the street vendors' attire and their cooking tools in street vendor were unsanitary. Forty percent of the respondents ranked frying oil as the most unsanitary substance. Eighty percent of the respondents responded that an enforcement of hygiene should be imposed on the street foods vendor. There were significant differences (p<0.001) among the student's age in the opinion related to the reasons of eating street foods, hygiene enforcement, existence of street foods and interest of hygiene status of street foods. High correlation (p<0.05) between the frequency of street foods and snack intakes was shown, regardless of student's age. The result shows that those who eat snacks more than once a day tend to eat street foods more frequently. Aerobic plate counts in Kimbab in 5 different vendors exceeded 10$^5$/g and contamination levels of enterobacteriaceae or coliform in Kimbab exceeded more than 10$^3$/g, which did not satisfy the microbiological standards. In conclusion, although the respondents thought that the sanitation of street foods was poor, most of them want the street food vendor to be maintained with better hygiene condition. This indicated that the regulation for safe street foods should be enforced and educational information about the preparation and serving for safe street foods should be provided to street food vendor.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.90-90
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• 2022

Nicaragua is located in Central America, climatic conditions are considered tropical dry forest. Statistics reflex that in Nicaragua exits 24,000 rice farmers. National rice production only covers 73% of the national consumption. It exists two sowing system: irrigation and rainfed. Varieties used in both systems are mid-late maturity (120-135 days), there are 14 released varieties for irrigation, eight for rainfed, and eight landraces used in rainfed. The current breeding system (introduction of lines from Colombia) has increased the national production, however, has some limitation due to the lack of enough variability, reducing the proability of finding good genotypes and therefore the possibility of satisfying 100% of the demand. The purpose of this study was to analyze the problems that must be resolved in the short and long term to improve rice productivity in Nicaragua. In this paper we explain some proposal for an improvement plan. The selection of varieties with high adaptability to various cultivation environmental conditions it is necessary, also to thoroughly manage seed purity to supply certified seeds. In rice cultivation technology, it needs to improve seedling standing and weeding effect by improving soil leveling and water-saving cultivation technology. Also, proper fertilization and planting density must be established in irrigated and rain-fed areas. Furthermore, capacity must be strengthened by collecting and training with the most recent agricultural technology information, as well as by revitalizing the union rather than the individual farmer. It is necessary to develop varieties highly adaptable to the Nicaraguan cultivation environment, as well as to expand irrigation facilities and cultivation technology suitable for weather conditions in rain-fed areas. Last, it is necessary to maintain the consistency of agricultural policy for continuous and stable rice production in response to climate change events such as drought or intermittent heavy rain.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.11
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• pp.81-97
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• 1972

Experiments and investigations were done basically and practically for the purpose of labor saving in paddy rice cultivation especially on Homizil i.e. hoeing and herbicide, 1969. 8 concrete tanks were established on the open base of Keon Kuk University for comparison of percolation, dissolved oxygen and yield test of rice in the paddy plot of tank. The dimension of the bottom of each tank is square meter. Each of the 4 of the 8 tanks is 21cm in height and each of the remaining 4 tanks is 36cm. Each tank has a system that comprises 2 sets of tubes, each of which has 20 holes of 5mm in diameter scattered every side and is covered with nylon cloth taking water in the tank. One set consists of 4 P.V.C tubes. The first set is situated 8cm below the top of the tank and the second set is located at bottom layer inside the tank. The 4 tubes of each set are combined together and led to the glass tube which protects from inside to outside. And this inside-outside glass tube is connected to the small rubber tube. Also a glass tube is set 4cm below the top of the tank. Paddy loam was filled on sand in each of the tanks in the soil depth of either 15cm or 30cm. The depth of sand was 5cm in the soil depth of 15cm and 10cm in the soil depth of 30cm. (Fig. 1, 2 and 3). The paddy rice was grown in the tank. The percolation of water, the dissolved oxygen and the yield of rice were observed in the tank. And the dissolved oxygen was detected by Winkler method. A sandy paddy field of heavy percolation was selected at the field of the National Agricultural Material Inspection Center in Seoul. It was divided into 9 plots. These plots were given 3 treatments: (A) not hoeing, (B) hoeing one time and (C) hoeing two times. These treatments were replicated 3 times along the latin square design. The paddy rice was grown and sprayed with Stam F-34 in the all plots for the purpose of killing weeds before hoeing. The two types of paddy of field i.e. one for normal percolation and the other for ill drainage were selected at Iri Crop Experiment Station, Jeonla-Bukdo. Each field was divided into 24 plots for 8 treatments. They are: (A) not hoeing; (B) hoeing one time; (C) hoeing two times; (D) not hoeing but treating with herbicide, Pamcon; (E) hoeing one time and weeding two times also treating with herbicide, Pamcon; (F) hoeing two times and weeding one time a], o treating with herbicide, Pamcon; (G) hoeing two times and weeding two times also treating with herbicide, Pamcon, ; (H) usual manner. The labor hours and expenses needed for weeding in the paddy by hoeing were investigated in a farmer at Suwon and the price of herbicide and the yield of rice were taken out at Iri, Jeonla-Bukdo. The results obtained from the above experiments and investigations are as follows: 1. The relationship between percolation and dissolved oxygen shows that a very small amount of oxygen is detected in the soil water under 2cm below surface of earth in the paddy even when percolation is over 4.0cm per 24 hours (Tab. 1). 2. The relationship between percolation and yield of rice shows that the yield of rice increases in the percolation of 0cm and 1.5cm per 24 hours and decreases in the percolation of 2.5cm and 3.4cm in the plot of the 15cm ploughing depth and increases in the percolation of 1.4cm and 3.0cm and decreases in the percolation of 0cm and 4.0cm in the plot of 30cm ploughing depth (Tab. 1 and Fig. 5). 3. The yield of paddy weeded with Stam F-34 in the sandy field of heavy percolation in Seoul was 3.02 tons in the plot of not hoeing, 2.99 tons in hoeing one time and 3.05 tons in hoeing two times per hectare (Tab. 5). 4.1). 4. 1) The yield of rice per 10 ares in the field of normal percolation at Iri was 338kg in not hoeing, 379kg in hoeing one time, 383kg in hoeing two times, 413kg in spraying herbicide, Pamcon, and not hoeing, 433kg in spraying herbicide, Pamcon, and hoeing one time and weeding two times, 399kg in spraying herbicide, Pamcon, and hoeing two times and weeding one time, 420kg in spraying herbicide, Pamcon, and hoeing two times and weeding two times and 418kg in usual manner (Tab. 6-1). 2) The yield of rice per 10 ares in the field of ill drainage at Iri was 323kg in not hoeing, 363kg in hoeing one time, 342kg in hoeing two times, 388kg in spraying herbicide, Pamcon, and not hoeing, 425kg in spraying herbicide, Pamcon, and hoeing one time and weeding two times, 427kg in spraying herbicide, Pamcon, and hoeing two times and weeding one time, 449kg in spraying herbicide, Pamcon, and hoeing two times and weeding two times and 412kg in usual manner (Tab. 6-2). 5. 1) The labor hours for weeding by hoeing was 37.1 hours but 53.5 hours if hours for meal, smoking and so on are included, and the expenses including labor cost needed for weeding by hoeing in the paddy rice was 2, 346 Won per 10 ares at Suwon (Tab. 7). 2) The labor hours for weeding by spraying herbicide with hand sprayer in the paddy rice was about 5 hours per 10 ares at Suwon and the expenses for weeding by spraying herbicide in the paddy rice was 750 Won but 1130 Won if the loss by decrement of rice in the paddy field of ill drainage per 10 ares is calculated in estimation at Iri (Tab. 8). From these observations and investigations it is known that using of some kinds of herbicides Saves labor and expenses of weeding, almost without giving damages to the rice itself, in the field of normal or heavy percolation comparing usual manner of hoeing.

• Korean Journal of Veterinary Research
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• v.2 no.1
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• pp.27-36
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• 1962

Immune response to two methods of Newcastle disease virus vaccine, one inactivated and the other attenuated was observed and the data presented. (1) Administration of inactivated virus vaccine in an amount of 1.0 ml. by intramuscular route gave an appreciable immunity to Newcastle disease for a period of at least three-and-half months. (2) The chickens given attenuated virus vaccine in the drinking water produced satisfactory immunity as manifested by the fact that immunized birds showed resistance when challenged 105 days after the vaccination and maintained high degree of HI titer for a period of 75 days. (3) Vaccination with the attenuated virus vaccine in drinking water is very simple and time saving in procedure, although the duration of immunity seems to be slightly shorter than that proced by inactivated virus vaccine. The author wishes to express his appreciation, to Drs. Kyu Myung Lee, Chang Koo Lee, and Ryong Sook Kee of their suggestions and help. The author is also indebted to Dr. Chang Hi Lee, Director of Anyang Veterinary Laboratory, who allowed the use of the facilities of the laboratory, whitout which this experiment could not have been undertaken.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.27 no.7
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• pp.380-394
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• 2015

This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2014. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) The research works on the thermal and fluid engineering have been reviewed as groups of heat and mass transfer, cooling and heating, and air-conditioning, the flow inside building rooms, and smoke control on fire. Research issues dealing with duct and pipe were reduced, but flows inside building rooms, and smoke controls were newly added in thermal and fluid engineering research area. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the results for thermal contact resistance measurement of metal interface, a fan coil with an oval-type heat exchanger, fouling characteristics of plate heat exchangers, effect of rib pitch in a two wall divergent channel, semi-empirical analysis in vertical mesoscale tubes, an integrated drying machine, microscale surface wrinkles, brazed plate heat exchangers, numerical analysis in printed circuit heat exchanger. In the area of pool boiling and condensing, non-uniform air flow, PCM applied thermal storage wall system, a new wavy cylindrical shape capsule, and HFC32/HFC152a mixtures on enhanced tubes, were actively studied. In the area of industrial heat exchangers, researches on solar water storage tank, effective design on the inserting part of refrigerator door gasket, impact of different boundary conditions in generating g-function, various construction of SCW type ground heat exchanger and a heat pump for closed cooling water heat recovery were performed. (3) In the field of refrigeration, various studies were carried out in the categories of refrigeration cycle, alternative refrigeration and modelling and controls including energy recoveries from industrial boilers and vehicles, improvement of dehumidification systems, novel defrost systems, fault diagnosis and optimum controls for heat pump systems. It is particularly notable that a substantial number of studies were dedicated for the development of air-conditioning and power recovery systems for electric vehicles in this year. (4) In building mechanical system research fields, seventeen studies were reported for achieving effective design of the mechanical systems, and also for maximizing the energy efficiency of buildings. The topics of the studies included energy performance, HVAC system, ventilation, and renewable energies, piping in the buildings. Proposed designs, performance performance tests using numerical methods and experiments provide useful information and key data which can improve the energy efficiency of the buildings. (5) The field of architectural environment was mostly focused on indoor environment and building energy. The main researches of indoor environment were related to the evaluation of work noise in tunnel construction and the simulation and development of a light-shelf system. The subjects of building energy were worked on the energy saving of office building applied with window blind and phase change material(PCM), a method of existing building energy simulation using energy audit data, the estimation of thermal consumption unit of apartment building and its case studies, dynamic window performance, a writing method of energy consumption report and energy estimation of apartment building using district heating system. The remained studies were related to the improvement of architectural engineering education system for plant engineering industry, estimating cooling and heating degree days for variable base temperature, a prediction method of underground temperature, the comfort control algorithm of car air conditioner, the smoke control performance evaluation of high-rise building, evaluation of thermal energy systems of bio safety laboratory and a development of measuring device of solar heat gain coefficient of fenestration system.