• Title/Summary/Keyword: Chemical substances

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Changes of the Physico-Chemical and Microbiological Properties during Composting for Composting of Sewage Sludge (하수슬러지의 퇴비화과정 중 이화학성 및 미생물상 변동)

  • Lee, Hong-Jae;Cho, Ju-Sik;Bahn, Kyeong-Nyeo;Heo, Jong-Soo;Shin, Won-Kyo
    • Korean Journal of Environmental Agriculture
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    • v.17 no.1
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    • pp.16-21
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    • 1998
  • To study the possibility of agricultural utilization of sewage sludge, the changes of the substances physico-chemical and microbiological properties composting periods such as inorganic matter, the form of organic matter and nitrogen and the kinds and the population number of microorganisms were investigated. The results were summarized as follows ; Temperature and $CO_2$ generation, they were the highest in the second day of composting periods and then were gradually fallen. pH value was not changed in first day during composting periods, but in second day was rapidly increased and then it was constant of the range of 8.4∼8.6. The contents of $P_2O,\;K_2O$, CaO and Fe were a little increased during composting periods, while that of ${SO_4}^{2-}$and Mn were big increased with 253${\sim}$331% and 191${\sim}$208% in late composting periods in comparing with early composting periods, respectively. The contents of ether extracted materials, water soluble polysaccharides, hemicellulose and cellulose were decreased but that of resins and lignin were not changed during composting periods. The contents of total and organic nitrogen during composting periods were decreased with 15${\sim}$20% and 22${\sim}$35%, respectively, while that of inorganic nitrogen was decreased with 75${\sim}$116%. The population numbers of microorganism during composting periods was much too changed according to the kinds of microorganism and composting periods.

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Technical Review on Methodology of Generating Exposure Scenario in eSDS of EU REACH (유럽 신화학물질관리제도의 eSDS에 첨부되는 노출시나리오 작성법 개발 동향)

  • Choe, Eun-Kyung;Kim, Jong-Woon;Kim, Sang-Hun;Byun, Sung-Won
    • Clean Technology
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    • v.17 no.4
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    • pp.285-299
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    • 2011
  • As one of the REACH obligations, the extended safety data sheet (eSDS) should be communicated within the supply chain under the REACH Regulation. Based on technical guidance documents published on the ECHAs website and survey of EU's recent REACH-related informations, this paper includes a study on details of how to develop exposure scenarios (ES) such as structure of ES, process of ES develpoment, standard workflows and key input data to develop ES with an introduction of eSDS concept. This paper also contains an overview on operational conditions (OCs) and risk management measures (RMMs) that are what to consider when building an ES. The structure of Chesar (Chemical Safety Assessment and Report tool) developed by European Chemicals Agency (ECHA) is studied with a review of the available exposure estimation tools for workers, environment and consumers. Case example of generic exposure scenario (GES) for organic solvent is presented. To guide Korean EU-exporting companies, their participating roles in three steps of preparing ES are addressed.

Fruit-body Formation of Pleurotus florida on the Synthetic Medium (합성배지(合成培地)를 이용(利用)한 고온성(高溫性) 느타리버섯의 자실체(子實體) 형성(形成)에 관한 연구(硏究))

  • Hong, Jai-Sik;Kang, Kui-Hwan
    • The Korean Journal of Mycology
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    • v.11 no.3
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    • pp.121-128
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    • 1983
  • Nutritional and physio-chemical conditions for mycelial growth and fruit-body formation of Pleurotus florida were determined in synthetic media. Mannitol and sucrose were good sugar substances for the mycelial growth and fruit-body formation whereas less mycelial growth and no fruit-body formation was obtained with arabinose, lactose and inulin. The optimum concentration of mannitol was about 2%. Peptone as a nitrogen sources resulted in a rapid mycelial growth and fruit-body formation with higher yield, but nitrite-nitrogens inhibited the mycelial growth. The higher yield was obtained with 0.2% peptone. Among the vitamins used, the greatest mycelial growth and fruit-body formation brought about by thiamine and folic acid. $KH_2PO_4$ and $MgSO_4$ at 0.2% and 0.02%, respectively, were effective for the mycelial growth and fruit-body formation, but other inorganic salts used were ineffective. The optimum temperature for mycelial growth and fruit-body formation were $25^{\circ}C$ and $20^{\circ}C$, respectively, and light intensity of $100{\sim}500\;lux$ and pH 6.0 appeared to be effective.

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Characterization of Secondary Exposure to Chemicals and Indoor Air Quality in Fire Station (소방서 실내공간의 화학적 유해인자 2차노출과 실내공기질 특성)

  • Kim, Soo Jin;Ham, Seunghon;Jeon, Jeong Seok;Kim, Won
    • Fire Science and Engineering
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    • v.33 no.4
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    • pp.140-151
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    • 2019
  • It is to assess the indoor air quality of the chemical hazardous materials exposed to the fire after firefighters returned to the fire scene. The research subject randomly selected four fire stations located in Seoul, Korea. Two fire stations were set up as control groups after the return of the firefighting activities at the actual fire scene, and two other fire stations were set up as control groups to measure the air quality of the room at normal levels regardless of the action. We conducted 24-hour monitoring for all fire accidents that occurred in Seoul Metropolitan using fire safety map computer system. Also, indoor air quality was measured immediately after homecoming if the experiment group was to be dispatched due to an accident of intermediate or larger scale. 11 hazardous substance items such as fine dust, formaldehyde, volatile organic compounds, PAH, VCM, acidity, asbestos, CO2, NO2, O3 were measured according to the process test method. Three of 11 types of harmful substances exceeded domestic and foreign standards, and one of them was found to be close to foreign standards. In particular, total volatile organic compounds, carbon dioxide and sulfuric acids were 2.5 times, 2.2 times and 1.1 times higher than the standard. Also, for formaldehyde and sulfuric acid, it was measured higher in the control group than in the case group. This findings could be used in policies to improve indoor air quality in the fire station of the Seoul Metropolitan Government.

The Effect of the Reaction Time Increases of Microbubbles with Catalyst on the Nitrogen Reduction of Livestock Wastewater (가축분뇨의 마이크로버블과 촉매와의 반응 시간 증가에 따라 질소 제거에 미치는 영향)

  • Jang, Jae Kyung;Sung, Je Hoon;Kang, Youn Koo;Kim, Young Hwa
    • Journal of Korean Society of Environmental Engineers
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    • v.37 no.10
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    • pp.578-582
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    • 2015
  • It was investigated whether the removal of nitrogen ions included livestock wastewater were increased by increasing the reaction time of livestock wastewater and microbubbles with catalyst. For this study, the nitrogen reduction system using microbubbles with catalyst was used. The two reactors were consecutively arranged, and the second reactor (Step 2) was located to next the first reactor (Step 1). Each reactor was reacted for 2 hours and air or oxygen as oxidant was fed into the reactor during operation before microbubble device. When oxygen was used, ammonia nitrogen was removed each 18.3% and 52.8% during 2 (only step 1) and 4 (step 1 and step 2) hours reactions. This value was higher than that of when air was fed. When oxygen was used, the longer the reaction time, the ammonia nitrogen removal was higher. The longer the reaction time, the higher the nitrite and nitrate was also removed such as ammonia nitrogen. Also this system was examined whether organic matter removal is effective. The total chemical oxygen demand (TCOD) removal was higher than the soluble chemical oxygen demand (SCOD). Some materials among causing substances COD were difficult to decompose biologically. Therefore, it means that it will be easy to operate the biological processes following step and reduce the concentration of organic contaminants in effluent.

Oxidation Stability of Lavers Made with Garlic-Salt and Their Characteristics during Storage (마늘맛 조미 김의 산화안전성 및 저장특성 연구)

  • Jeon, Ye-Sook;Park, Soo-Jin;Choi, Mi-Kyeong;Kang, Myung-Hwa
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.37 no.1
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    • pp.83-89
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    • 2008
  • In order to evaluate the oxidation stability, chemical compounds, and sensory for the garlic-salt laver, we prepared the garlic-salt laver added with different levels of salt and garlic power. The lipid per oxidation of garlic-salt laver was monitored by measuring the formation of 2-thiobarbituric acid reactive substances (TBARS). In addition, the general chemical compounds of laver with garlic-salt were determined by moisture, crude lipid ash, and protein. The major tocopherol compounds of laver with garlic-salt were measured using HPLC system. The contents of ${\alpha}$-tocopherol decreased with time, in contrast to ${\gamma}$-tocopherol which increased with time. The lipid profiles of laver with garlic-salt were high in linoleic acid although they did not change with time. Formation of TBARS of laver increased in control but did not increase in laver with garlic-salt. After 12 weeks, laver with 33% garlic-salt showed strong inhibition effect on TBARS formation. The sensory evaluation of laver with garlic-salt were tested. The results seem to indicate that laver with 33% garlic-salt can be used as a good ratio.

Fluorine Contens of the Underground Waters in the Choong Nam Province (I).-the town ONYANG- (忠南地區 地下水 中의 弗素含量 調査에 關한 硏究 (I)-溫陽邑內)

  • Park, Kyu-Chang;Park, Jong-Yul
    • Journal of the Korean Chemical Society
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    • v.14 no.1
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    • pp.75-83
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    • 1970
  • 66 samples of underground waters at the town Onyang were collected and analyzed from August 19 to November 5, 1969. Fluorine more than 1.0 mg/l is contained in the under ground waters in the region 0.9 km away from the Onyang hot springs, fluorine more than 0.3 mg/l in the waters in the region 1.2 km away from the hot springs, and 0.04-0.29 mg/l fluorine in the waters in the region from 1.2 km to 3.9 km away from the hot springs. It is advisable that the residents in their teeth growing ages must not drink the underground waters in the region 1.2 km away from the hot springs because the waters cause dental trouble (mottled teeth) and they may drink the waters in the region from 1.2 km to 3.9 km away from the hot springs for the fluoridation of their teeth. It is reasonable to suppose that the high fluorine contents of the underground waters are caused mainly by the contamination of the hot spring waters in which fluorine and calcium in rock are dissolved, in the region 1.2 km away from the hot springs, and that the waters in the region from 1.2 km to 3.9 km away from the hot springs contain much fluorine produced by the decomposition of organic substances.

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Micromorphology and Chemical Composition of a Sialolith in the Submandibular Gland Duct (악하선 내 타석의 미세형상 및 화학적 조성)

  • Im, Yeong-Gwan;Song, Ho-Jun;Kim, Byung-Gook
    • Journal of Oral Medicine and Pain
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    • v.36 no.3
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    • pp.161-167
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    • 2011
  • Sialolith is one of the most common pathologic conditions found in the salivary glands. The mechanisms responsible for the formation of sialoliths have not been elucidated so far. In this article, the chemical composition and micromorphology of a sialolith of a 58-year old female patient suffering from chronic sialoadenitis of the submandibular gland was analyzed using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). In a SEM evaluation, the highly mineralized amorphous core surrounded by lamellar and concentric structures was revealed, however no foreign body, organic material, or signs of microorganism were observed in the core of the sialolith. EDX analysis showed the central core was composed of only Ca, O and P, and that a high level of C was detected near the central area as well. These results indicated that the inorganic composition of the sialolith was hydroxyapatite crystals, and that inorganic and organic substances existed around the central cores. This study suggests that the sialolith was composed mainly of hydroxyapatite crystals and the formation of the nucleus of the sialolith in the submandibular gland duct was secondary to sialadenitis, which favors the growth of an inorganic crystalline nucleus.

Pharmacological Action of Ginseng (인삼의 약리작용)

  • 홍사악;임정규;박찬웅;차인준
    • Journal of Ginseng Research
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    • v.3 no.1
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    • pp.66-93
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    • 1979
  • Panax ginseng C. A. Meyer, which has been known for more than EWO years. occupies a Particular prince in folk medicine as so called tonic remedy. The pharmacolgical investigations of ginseng, based on the scientific concepts and methodology, have been performed by many researchers through the past 50∼60 years at different parts of the world. The pharmacological action of Panax ginseng compiled from the numerous reports can be summarized as follows: 1. On central nervous system, the effect of Panax ginseng is timulatory in smaller doses and somewhat depressive in larger doses. From the psychopharmacological aspect, ginseng seems to increase the mental efficiency of man. 2. Ginseng has the effect tending to Protect organism from various physical and chemical stresses. 3. The growth and basal metabolic rates of experimental animals are stimulated by ginseng. Ginseng also prolongs the survival time of animals under adverse influences. 4. Increasing the physical and mental efficiency, ginseng postpones the onset of fatigue and increases the working capacities. 5. In the case of the intravenous administration of ginseng, a transitory and slight hypotensive effect is observed. These hypotensive effects seems to include that of a direct action and actions related to the release of histamine and/or serotonin by ginseng. 6. It is Presumed that ginseng lowers the elevated bleed ingar and cholesterol level. 7. Ginseng tends to increase the gastrointestinal motizity and tone 8. It is presumed that ginseng Promotes the iron metabolism and activates the hematopoietic factors. 9. Ginseng tends to stimulate the biosynthesis of nucleic acid and release of histamine and serotonin. 10. The toxicity end adverse reactions of ginseng appear to be nothing that warrants apprehension. 11. Anticancer erects of ginseng seem to be due to indirect action rather than direct action on cancer cell, by improving the host condition 12. Recent clinical trials of ginseng harts obtained sent good results, but Present trial is still limited in its range, so it is necessary to broaden the scope of trial covering many kinds of organs and diseases. From the above, although it appears that substantial advancements have been achieved in the studies on the Pharmacological actions of Panax ginseng there are many discrepancies noticed in the reported data. Furthermore the precise mechanisms of actions of ginseng are sometimes obscure, even unknown in other actions as the students stand now. The main reasons for this are considered to be that even though saponin has been identified at one of the active substances of ginseng, other components have not fully been identified and that the experimental approaches of the investigations varied with different researchers. Thus a thorough analysis of the chemical components and newer standardized concepts and metohds appear to be the pre-requisites for further study of the pharmacolgical effects and mechaisms of Panax ginseng.

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Effect of collection time on the chemical composition and levels of thiobarbituric acid reactive substance of Godulbaegi (Youngia sonchifolia M.) (채취시기에 따른 고들빼기의 성분 조성과 산화방지활성)

  • Hwang, Tae Yean;Huh, Chang Ki
    • Food Science and Preservation
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    • v.24 no.6
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    • pp.786-794
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    • 2017
  • This study analyzes the chemical composition and thiobarbituric acid reactive substance levels of Godulbaegi (Youngia sonchifolia M.) depending on collection time. The moisture and crude fat content in leaf and root decreased, while crude fiber, crude protein, carbohydrate, and ash increased with increases in collection time. The mineral elements tended to increase in each sample with increases in collection time. The content of vitamin B increased as collection time increased. Vitamin C content was approximately five times higher in the leaves than that in the roots. Total amino acids in leaf and root increased considerably as collection time increased content of phenolic compounds in root were higher than that in the leaf and these contents increased. Antioxidant activity of Godulbaegi was higher in the root than in the leaf and increased as collection time increased.