• 환경위생공학
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• 제12권1호
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• pp.25-37
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• 1997

The synthesis of high purity and ultra-fine $BaTiO_{3}$ by precipitation with gaseous $NH_{3}$ as precipitator was investigated to find an alternative process to solve various problems of present wet methods. This study consisted of two parts ; synthesis of $BaTiO_{3}$ precipitation with gaseous $NH_{3}$ and test of electrical property for the $La_{2}O_{3}$ doped $BaTiO_{3}$. The proper condition for the synthesis of $BaTiO_{3}$ by precipitation with gaseous $NH_{3}$ is as follows. The pH was 9.0. $H_{2}O_{2}$ mole ratio to $TiCl_{4}$ was 10. $NH_{3}$ gas follow rate did not influence the synthesis of $BaTiO_{3}$. The calcination temperature of $BaTiO_{3}$ was $300^{\circ}C$. Also, the synthesis of $La_{2}O_{3}$-doped $BaTiO_{3}$ was tested through the wet process. Under these condition, the shape of prepared $BaTiO_{3}$ powder was spherical type and the size of that was about $0.2{\mu}m$. After the powder was pressed, this green body was sintered at the $1300^{\circ}C$. Under these conditions, the water absorptance and the density of the obtained sintered body were below 0.04 %, 5.2 g/$cm^{3}$, respectively. Also the grain size of that was about $10{\mu}m$ and it was similar to commercial product.

• 환경위생공학
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• 제10권2호
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• pp.1-12
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• 1995

Under accelerated industrial developments environment pollution comes out to be very stirious. Especially the ions of heavy metal from wastewater, even if they are minimal, accumulated in ecology circle and do finally injury to human health. The general process for removal of heavy metals include coagulation and following sedimentation, ion -exchange and active carbon adsorption and sedimentation that applicate in popular, needs the expense of coagulant the additional treatment of sludge on the general process of coagulation and sedimentation. It is also a serious problem that the second pollution caused by coagulant. However chelating adsorption that uses natural chelating high- molecular compound has not pollution problem Among chelating high- molecules, the diminishing chitin that contained in crustaceans as crawfish and crab in our country with affluent water resources are easy to get. So it is advantageous to use this ubiquitous material for removing heavy metals because we could reuse natural resource. In this research, the author tested the effectiveness of the adsorption and removal of heavy metal ions by chitin and its derivatives. Chitin and cellulose became beads and used as flocculant, in this test. The results are as follows . First, bead showed higher removal ratio than powder in the comparative test on adsorbents such as chitin, chitosan and cellulose. Secondly, in the variety test by the kinds of adsorbent and time. chitosan bead and cellulose bead that showed the highest removal ratio. One hour need to remove the ions of heavy metal. Thirdly, the results of the adsorption degree test by pH revealed high removal ratio adsorption of chitin, cellulose and chitosan bead in alkalin condition but chitosan bead in acidic condition.

• 환경위생공학
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• 제13권3호
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• pp.79-84
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• 1998

The study result on the domestic waste occurrence and admistration condition of Iksan City as follows ; 1. The year of 1995 has observed a radically decreasing ratio of per capita waste generation compared to the previous year by 26.2%, owing to the publication of the new amendment of volume based charge as well as to the rural population included through the merger of Iksan City and Iksan Country ; the daily quantity of domestic waste for Iksan residents in 1997 was calculated to be $0.66kg/capita{\cdot}day$. 2. Waste generation in nonresidential areas were $8.04kg/capita{\cdot}day$ in average ; the quantity per capita in market places was observed to generate the largest, $36.76kg/capita{\cdot}day$, while that of services was the smallest $0.25kg/capita{\cdot}day$. 3. The average generation per capita of household waste was $0.23kg/capita{\cdot}day$ in the area which has no volume based charge system. This area showed no difference from those of other areas ; the apparent density of the waste recorded the lowest $0.llkg/{\ell}$ for District Offices, while the highest among the classified fields was $0.40kg/{\ell}$ of the Fire Station. 4. Iksan City showed great contribution by decreasing the absolute quantity of waste for landfill by waste classfication, according to the days of the week and reutilizing recyclable waste since August, 1997. 5. Location of a landfill site for disposal of nonrecyclable waste will cause a serious problem to the community and it will be highly recommendable to have governmental support and professtional consultation as well as open discussions, such as hearings, for the settlement of the problem.

• 환경위생공학
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• 제24권1호
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• pp.47-55
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• 2009

Indoor air Quality in public facility same as bus terminal and subway station is very important for civil health. The purpose of this study was to investigate the concentration and distribution of PM10 and falling microorganism at the 5 subway stations and bus terminals from Summer 2003 to Summer 2005 in Kyunggi Province. The results were as follows. 1. The highest concentration of PM10 was $187ug/m^3$ at Bucheon Bus Terminal in 2005 while the lowest concentration of PM10 was $78ug/m^3$ at Suwon Bus Terminal in 2003. The year variation of PM10 concentration at the bus terminals in Kyunggi Province was in order of 2005 > 2004 > 2003. The average concentration of PM10 at the five Bus Terminal was $127ug/m^3$. 2. The highest concentration of PM10 was $225ug/m^3$ at Euijungbu Station l in 2004 while the lowest concentration of PM10 was $115ug/m^3$ at Suwon Station in 2003. The year variation of PM10 at the subway stations in Kyunggi Province was in order of 2004 > 2005 > 2003. The average concentration of PM10 at the five subway stations was $164ug/m^3$. 3. The average amount of falling microoganism at the five bus terminal in Kyunggi Provinc was 201CFU/plate. The minimum is 124 CFU/plate at Seongnam Bus Terminal in 2004 while the maximum is 268CFU/plate at Euijungbu Bus Terminal in summer 2005. The higher concentration of PM10 was 206CFU/plate in 2004 than 199CFU/plate in 2003 and 2005. 4. The minimum is 107CFU/plate at Anyang station in 2003 while the maximum was 263CFU/plate at Euijungbu station in 2003. The average amount of falling microoganism at the five subway stations in Kyunggi Province was 179 CFU/plate. The year variation of falling microorganism at the subway stations in Kyunggi Province was in order of 2004 > 2005 > 2003.

• 환경위생공학
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• 제18권3호통권49호
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• pp.35-42
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• 2003

The electric resistance and constant current were investigated on the nickel-thallium-phosphorus alloy deposits by electroless-plating. The Ni-Tl-P alloy deposits were achieved with a bath using sodium hypophosphit as the reducing agent and sodium citrate as the comlexing agent. The basic plating solution is composed of 0.1M NiSO$_4$, 0.005${\sim}$0.0IM Tl$_2$S0$_4$, 0.1${\sim}$O.2M sodium hypophosphite and 0.02${\sim}$O.IM sodium citrate and the plating condition were pH 5${\sim}$6, temperrature 80$_4$90${\circ}$C. The results obtained are summarized as follows: 1) The crystal structure of deposit was amorphous structure as deposited state, became microcrystallized centering on Ni(111) plane by heat treatment at 200${\circ}$C, and grew as polycrystalline Ni, Ni$_3$P, Ni$_5$p$_2$,Tl, etc. by heat treatment higher than 350${\circ}$C. The grain size of plated deposits was grown up to 28.3~42.0nm by heat treatment for 1hour at 500${\circ}$C. 2) The electrical resistivity showed a comparatively high value of 192.5$_4$208.3 ${\mu}$${\Omega}$Cm and its thermal stability was great with resistivity value less than 0.22% in the thermal surroundings of 200${\circ}$C. 3) Ni-Tl-P alloy deposit showed such good constant current-making-effect in the variation of electric voltage, heat treatment temperature, and the composition of the deposit that it can be put to practical use as the matter of constant current device.

• 환경위생공학
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• 제4권2호
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• pp.61-90
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• 1989

The purpose of this study was to identify and name clusters of school health program, and to describe some of the characteristics of administrative supports. The literature, materials and public documents were analysed by the chronological events from 1945 to 1989. The result of this study is as follows : 1. A brief summary of the history of school health program was included as an introduction to the analysis of the current programs of school health. Five current school health-program clusters were identified from findings of a study of programs ; 1) Physical assessment, laboratory examination and health services for the students, 2) health insturction 3) healthful living condition(environmental health), 4) health clinic management 5) administrative supports. 2. The earliest school-based efforts focused on communicable disease prevention by the ministry of health and social affairs. Annual medical inspection(health assessment) for school children for eyes, ears, nose, and throat were mandated nation-wide in 1951 by physical Assessment Act. 3. In 1979, the health instruction of schools to improve the health status of students was improved by health department in the Ministry of Education. 4. Experiences in healthful environment were basic components of the school health program. However, without careful planning and supervision these experiences were not contributed to the goal of school health. The formal program of school health environment were initiated in 1979. 5. In 1980, the guidelines of school health clinic management were prepared by Ministry of Education such as guidance of essential degrees and facilities in school health clinic. 6. Two patterns of administration of school health programs existed in Korea. In one the school health department operated its own health program and in the other the physical education department operated the health program within the school system. The school health department was established in Ministry of Education from 1979 to 1982. Improved school health programs will be a key element in the comprehensive national child health policy whic I will ask the Ministry of Education to develop for the Department.

• 한국축산시설환경학회지
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• 제20권4호
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• pp.177-182
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• 2014

This research was conducted to grasp the present condition of environmental management relating to Korea detector dogs that performed their duties such as detection and lifesaving. We directly conducted a survey throughout visit to five government agencies. In environmental management case, average length and width of kennels were 1.78 m and 3.50 m, respectively. Types of floor were searched as coating cement, tile, ucrete and concrete. Most of government agencies ventilated kennels using ventilation fan systems with natural ventilation. But there were differences between government agencies in frequencies of the sanitary management items. On the other side, major diseases of the German shepherd breed as a major detector dog were in order of arthritis, measles, earache, and dermatosis. And their daily training time was average 4 hours. Finally, it is thought that these results could be used as a basic data of standard breeding management manual of Korea detector dog.

• 환경위생공학
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• 제18권4호
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• pp.24-35
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• 2003

Recent epidemiologic studies revealed that the concentration of air pollutants and fine particulated matter have some effects on health status and are associated with increased mortality and morbidity. The purpose of this study was to characterize background mass concentration of fine particle (PM2.5) and metallic composition from September 2001 to August 2002 in comparison with a medium city, Asan and metropolitan city, Seoul. Conclusively, proper management for fine particles was required in a medium city, Asan, considering the concentrations of metallic elements in fine particles in Asan were relatively higher than those in Seoul. The results were as followed. 1. Average mass concentrations of fine particles in Asan and Seoul were 37.70(${\pm}18.41{\;}{\mu}g/\textrm{m}^3$) and 5.83(${\pm}38.50$) ${\mu}g/\textrm{m}^3$, respectively. When the weather conditions were classified as normal and yellow-sand, measured average mass concentrations of fine particles in yellow-sand weather condition was significantly higher than those of normal weather condition in both cities (p<0.05). 2. Depending on seasons, measured average mass concentrations of fine particles in Asan and Seoul in spring were 47.76(${\pm}19.07$) ${\mu}g/\textrm{m}^3$m and 61.53 (${\pm}4.37$) ${\mu}g/\textrm{m}^3$, respectively. In summer, the average mass concentrations of fine particles in Asan and Seoul were 29.44(${\pm}9.85$) ${\mu}g/\textrm{m}^3$ and 25.42(${\pm}8.10$) ${\mu}g/\textrm{m}^3$, respectively. Especially, the concentration was the highest in spring and the lowest in summer among four seasons. 3. Average concentrations of manganese(Mn), iron(Fe), chromium(Cr), cadmium(Cd), lead(Pb) and silicon(Si) in fine particles in Asan were significantly higher in Seoul (p<0.05). Average concentration of Si in fine particle in Asan was statistically higher than that of Seoul during yellow -sand condition (p<0.05). 4. Considering the characterization of four seasons, average Pb concentration of fine particle in Asan is significantly higher than that of Seoul in spring(p<0.01). In summer, average Mn and Cr concentrations of fine particle in Asan is higher than those of Seoul (p<0.05). Average Mn, Fe. Cr and Si concentrations in fall (p<0.05), and average Mn, Fe, Cr, Pb, and Si concentrations in winter (p<0.05) in Asan were higher than those of Seoul, respectively. 5. Mass concentrations of each Mn, Fe, Cd and Si in fine particles were significantly correlated with both cities. In normal weather condition, Mn, Cu and Si concentrations are statistically significant in Asan, while Mn, Fe, Cu and Si concentrations are statistically significant in Seoul. Mn, Fe and Si concentrations in both cities were statistically significant during yellow-sand weather.

• 환경위생공학
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• 제7권2호
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• pp.1-10
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• 1992

Since 1960's along with industrialization and urbanization, economic growth has been . achieved, however, at the same time, environmental condition has been seriously deteriorated. . Currently, volume of wastewater has been increasing at annual rate of 7% in sewage and 20% in industrial wastewater. However, the nation's sewage treatment serves only 33% of the municipal wastewater as of 1991. Major portion of air pollutants comes from combustion of oil and coal which comprise 81% of total energy use and emission gases from motor vehicles increasing at an accelerated rate. It is known that Korea generates the highest amount of waste per capta. Nevertheless, it is not sufficient to reduce the volume of waste by means of resources recovery and recycling. Recognizing the importance of global environmental problems such as ozone layer depletion, global warming and acid rain, international society has been making various efforts since the 1972 Stockholm conference. In particular, it is expected that the Rio conference which has adopted the Rio declaration and Agenda 21 will form a crucial turning point of the emerging new world order after the Cold War confrontation. To cope with such issues as domestic pollution and global environmental problems, the fundamental national policy aims at harmonizing "environmental protection and sustainable development". The Ministry of Environment has recently set up a mid-term comprehensive plan which includes annual targets for environmental protection. According to the government plan, gradual improvement of various environmental conditions and specific measures to achieve them is planned in time frame. Additional sewage treatment plants will be constructed in urban areas with the target to treat 65% of the nation's municipal sewage by 1996. Supply of clean fuels such as LNG will also be expanded starting from large cities as a cleaner substitute energy for coal and oil. In parallel with expansion of LNG, emphasis will be placed on installation of stack monitoring system. Due to the relatively limited land, government's basic policy for solid waste treatment is to develop large scale landfill facilities rather than small sized ones. Thirty three regional areas have been designated for the purpose of waste management. For each of these regions, big scale landfill site is going to be developed. To increase the rate of waste recycling the government is planning to reinforce separate collection system and to provide industries with economic incentives. As a part of meeting the changing situation on global environmental problems after UNCED, and accommodation regulatory measures stipulated in the global environmental conventions and protocols, national policy will try to alter industrial and economic structure so as to mitigate the increasing trends of energy consumption, by encouraging energy conservation and efficiency. In this regard, more attention will be given to the policy on the development of the cleaner technology. Ultimately, these policies and programs will contribute greatly to improving the current state of national public health.

• 환경위생공학
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• 제21권1호
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• pp.44-51
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• 2006

This study was conducted to investigate air quality in the underground parking lot of department store. Sampling sites were selected to the three sites in one department store. Measuring instrument started from November 3rd, 2005 to November 9, 2005. Target air quality parameters include a number of criteria pollutants such as NOx, $O_3$. The purpose of this study was to find out the present condition of indoor air quality in underground parking space of department store. Through the field measurement, the current situation and the behavior of contaminants were investigated and then was compared with the advice standards. The result of this study was as follows; The Average density of NOx gas and $O_3$ gas was maintained below the indoor air advice standards. The Average density of NOx gas and $O_3$ gas was highly measured during the weekend than during the week day. Average density of NOx gas and $O_3$ gas was highly measured at daytime than that of afternoon. Average density of NOx gas was highly measured in the center area than the other area. Average density of $O_3$ gas was highly measured at the entrance than the other area. NOx gas concentration was maintained below 0.3ppm, an average for 1 hours, as defined in the parking space law. $O_3$ gas concentration was maintained below 0.08ppm, an average for 1 hours, as defined in the parking space law.