• Title/Summary/Keyword: Chemical properties

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Impacts of Soil Microbial Populations on Soil Chemical and Biological Properties under Tropical Dry Evergreen Forest, Coromandel Coast, India

  • Sudhakaran, M.;Ramamoorthy, D.;Swamynathan, B.;Ramya, J.
    • Journal of Forest and Environmental Science
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    • v.30 no.4
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    • pp.370-377
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    • 2014
  • There are very few studies about soil chemical and biological properties under tropical dry evergreen forest Coromandel Coast, India. The present study was conducted in six tropical dry evergreen forests sites such as Oorani, Puthupet, Vadaagram, Kotthatai, Sendrakillai and Palvathunnan. We measured the quantity of soil chemical, biological properties and selected soil microorganisms for investigating the impacts of soil microbial populations on soil chemical and biological properties. The result showed that total N, P, Ca, S, Fe, Mn, Cu, Co, exchangeable K, Olson P, extractable Ca and phosphobacterial population were higher in the soil from Kothattai forest site. Organic carbon, total Mg, extractable Na, soil respiration, ${\beta}$-glucosidase activity, bacterial population, fungi population and actinomycetes population were higher in the soil from Palvathunn forest site. Total K, $NH_4{^+}$-N, $NO_3{^-}$-N, exchangeable K, extractable Ca, extractable Na, azotobacter population, bacillus population and rhizobacteria population were higher in the soil from Sendrakillai. Beijerinckia population, rhizobacteria and soluble sodium were higher in Puthupet forest soil. Total Si, total Na and exchangeable K were higher in soil from Oorani forest site. Total Mo and exchangeable K were higher in the soil from Vadaagaram forest site. The results showed that organic carbon, total N, $NH_4{^+}$-N, $NO_3{^-}$-N, extractable P, extractable Ca, soil respiration and ${\beta}$-glucosidase were significantly correlated with soil microbial populations. Therefore soil microorganisms are important factor for maintaining soil quality in tropical dry evergreen forest.

Settling Characteristics of Saemankeum fine-Cohesiv Sediments : Effects of Physico-Chemical Properties (새만금 미세점착성 퇴적물의 침강특성 : 퇴적물의 물리.화학적 특성의 영향)

  • Hwang, Gyu-Nam;Jo, Yong-Sik
    • Journal of Korea Water Resources Association
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    • v.35 no.5
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    • pp.475-484
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    • 2002
  • A series of settling tests and physico-chemical property tests on Saemankeum fine-cohesive sediments has been conducted in order to investigate the correlation between settling properties and their physico-chemical properties which are represented as grain size distribution, mineralogical composition, and percentage of organic contents. Experimental results of physico-chemical property tests show that Saemankeum sediments are relatively large in average grain size(52${\mu}{\textrm}{m}$), and contain very small organic materials(2%), and are dominantly composed of Quarts in mineralogical aspect which has relatively low cohesion. Thus, Saemankeum sediments might be specified as the sediments whose settling properties are more influenced by the gravity than the cohesion. This characteristics of Saemankeum sediments are found to lead to relatively small settling velocity in flocculated settling region in which increasing cohesion results in increasing settling velocity, while relatively large settling velocity in hindered settling region in which settling velocity decreases with increasing cohesion.

Effect of Oxygen Supply on Chemical Composition and Physical Properties of Tobacco Leaves During Flue-curing (잎담배 건조중 산소공급에 따른 내용성분 및 물리성 변화)

  • 황건중;석영선
    • Journal of the Korean Society of Tobacco Science
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    • v.18 no.1
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    • pp.49-53
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    • 1996
  • This experiment was carried out to study the effect of oxygen on chemical composition and physical properties of tobacco leaves during flue-curing. The results obtained were as follows: Starch content decreased and sucrose content increased with increasing oxygen supply during curing. Glucose and fructose of the cured leaves showed high content at the 5-10% oxygen supply. Amino-N and nitrate-N increased with increasing oxygen supply. Total nitrogen and NH4-N showed the lowest value at the 5-10% and 10-15% oxygen supply in the cutters and leaf, respectively. Chlorophyll and chlorogenic acid increased, and total volatile base decreased with increasing oxygen supply. The activity of α-amylase increased at the latter period of flue-curing, and the maximum activity point were delayed 12 hours with increasing oxygen supply. Shatter index of cured leaves decreased with increasing oxygen supply. It was desirable to supply oxygen during flue-curing for the improvement of chemical and physical properties such as starch, total sugar, chlorogenic acid, and shatter index of cured leaves.

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The Weatherability and Chemical Resistance of CFRP (탄소섬유판 복합재료의 내후성/내화학성에 관한 연구)

  • 최영철;윤희석
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2002.05a
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    • pp.151-154
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    • 2002
  • The durability of two kinds of CFRP plates, carbon/UP and carbon/V, was studied under severe environmental conditions. Immersion into the chemical solutions and accelerated weathering were executed on the CFRP plates and the weight change under each condition was measured. After those treatments, the plates were tested by tensile testing machine to measure the mechanical properties and observed by SEM to find the damage behaviour of the surface. Comparing the virgin plates and the chemically exposed plates, both plates show severe deterioration of the mechanical properties. But, the plates subjected to alkali solution show much larger reduction than those of acidic solution and carbon/V has better chemical resistance than carbon/UP. The material properties of CFRP plate exposed to the weathering were deteriorated linearly proportional to the exposure time.

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Environmental effect on the chemical properties of star forming galaxies in the Virgo cluster

  • Chung, Jiwon;Rey, Soo-Chang;Kim, Suk;Lee, Ung
    • The Bulletin of The Korean Astronomical Society
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    • v.38 no.2
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    • pp.46.2-46.2
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    • 2013
  • We utilize Sloan Digital Sky Survey DR7 spectroscopic data of ~380 star forming galaxies in the Virgo cluster to investigate their chemical properties depending on the environments. The chemical evolution of galaxies is linked to their star formation histories as well as to the gas interchange in different environments. We derived star formation rate (SFR) and gaseous metallicity (e.g., oxygen abundance) of star forming galaxies. Combining with GALEX ultraviolet photometry and ALFALFA HI 21 cm data, we examine the relations between SFRs, metallicity, and HI deficiency of galaxies in various regions of the Virgo cluster. We also quantify the degree of ram pressure around galaxy using the ROSAT X-ray surface brightness map. We discuss environmental effects on the chemical properties and evolution of star forming galaxies.

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Detoxification Properties of Surface Aminated Cotton Fabric (아민화 표면 처리된 면직물의 제독 성능 연구)

  • Kim, Changkyu;Kwon, Woong;Jeong, Euigyung
    • Textile Coloration and Finishing
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    • v.32 no.2
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    • pp.73-79
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    • 2020
  • Pursuing the fabric materials for military chemical warfare protective clothing with the improved detoxification properties, this study investigated the simple and effective cotton treatment method using pad-dry-cure process and 3-aminopropyltrimethox ysilane(APTMS) solution for surface amination. Detoxification properties of the untreated and treated cotton fabrics were evaluated via decontamination of chemical warfare agent simulant, DFP(diisopropylfluorophosphate). The surface aminated cotton fabric increased the rate of the hydrolysis of DFP by the factor of 3 and the decontamination ratio reached 88.2% after 24h. Therefore, the surface amination of the cotton fabric with APTMS can be an effective pathway to prepare the material for protective clothing against chemical warfare agents.

Thermal Properties and Water Sorption Behaviors of Epoxy and Bismaleimide Composites

  • Seo, Jong-Chul;Jang, Won-Bong;Han, Hak-Soo
    • Macromolecular Research
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    • v.15 no.1
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    • pp.10-16
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    • 2007
  • In this work, we prepared epoxy/BMI composites by using N,N'-bismaleimide-4,4'-diphenylmethane (BMI), epoxy resin (diglycidyl ether of bisphenol-A (DGEBA)), and 4,4'-diamino diphenyl methane (DDM). The thermal properties and water sorption behaviors of the epoxy and BMI composites were investigated. For the epoxy/BMI composites, the glass transition and decomposition temperatures both increased with increasing BMI addition, which indicates the effect of BMI addition on improved thermal stability. The water sorption behaviors were gravi-metrically measured as a function of humidity, temperature, and composition. The diffusion coefficient and water uptake decreased and the activation energy for water diffusion increased with increasing BMI content, indicating that the water sorption in epoxy resin, which causes reliability problems in electronic devices, can be diminished by BMI addition. The water sorption behaviors in the epoxy/BMI composites were interpreted in terms of their chemical and morphological structures.

Preparation and Properties of Liquefied-Wood Polymer Composite (액화목재복합체(LWPC)의 제조 및 물성)

  • Kim, Chul-Hyun;Kim, Kang-Jae;Eom, Tae-Jin
    • Current Research on Agriculture and Life Sciences
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    • v.27
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    • pp.29-33
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    • 2009
  • Liquefied-wood polymer composite was prepared and mechanical properties was evaluated to develop potential utility of liquefied wood. The liquefied wood was made from waste wood and chemical modified with acetic anhydride and maleic anhydride (MA), phtalic anhydride (PA). The composite sheet was prepared from modified liquefied-wood and polymer(PE). The mechanical, chemical and microscopical properties composite sheet were investigated. The results were summarized as follows, 1. The tensile strength was increased and breaking elongation of composite sheet was decreased with the time of acetylation and the dosage of MA. 2. The Young's modulus of composite sheet was gradually decreased with the dosage of PA. 3. The peak intensity of 1737cm-1 in FT-IR spectra of chemical modified liquefied woods was increased. 4. The dispersity of liquefied woods with PE was improved with chemical modification.

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Morphology and mechanical properties of LDPE/PS blends prepared by ultrasound-assisted melt mixing

  • Ryu, Joung Gul;Kim, Hyungsu;Kim, Myung Ho;Lee, Jae Wook
    • Korea-Australia Rheology Journal
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    • v.16 no.3
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    • pp.147-152
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    • 2004
  • Ultrasound-assisted melt mixing was applied to blending polystyrene (PS) and low density polyethylene(LDPE). The influence of the ultrasonic irradiation on the morphology and mechanical properties of the blends was investigated. It was observed that the domain sizes of the blend were significantly reduced and phase stability was well sustained even after a thermal treatment. Such morphological feature was consistent with the improvements in mechanical performance of the blends. The desirable results of ultrasonic compatibilization are mainly attributed to the in-situ formation of PS-LDPE copolymers as confirmed by a proper separation experiment. An important relationship between ultrasonic irradiation time and mechanical properties is revealed and an issue on the thermal stability of the blend is discussed.