48 research outputs found

    NGHIÊN CỨU KHẢ NĂNG CHỐNG CHỊU VÀ HẤP THU CHÌ Pb, Zn CỦA DƯƠNG XỈ PTERIS VITTATA L.

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    Phytoremendiation is a new treatment technique in pollution which has been studying and developing in recent years. In comparison to the other techniques, this is proved to be more effective, economical and be able to prevent negative consequences. The results from the experiment named “the study about the resistibility and absorptivity  of the Pteris vittata fern to Pb and Zn” have shown that Pteris vittata can be able to resist Pb contained in the earth at a concentration of 3000 mg/kg, despite the fact that  its best level of Pb resistance and absorptivity is less than 1000 mg/kg of earth. In the case of Zn, this fern species can withstand to a concentration of 1500 mg/kg of earth. Whereas, Pteris Vittata can absort and store up the most when the Zn concentration in earth is 300 mg/kg. The content of Pb and Zn in fronds and roots of Pteris Vittata increases when the concentration of these two elements in earth rises up. Pteris vittata’s ability to store Pb and Zn is reduced by time, however, the effectiveness to eliminate these two elements increases as a consequence of increasing its biomass

    Tính chất cơ học của vật liệu compozit sử dụng prepreg trên cơ sở nhựa phenolic và epoxy gia cường sợi thủy tinh và thủy tinh-aramit

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    Prepreg composite materials are becoming increasingly common in the industry due to their ease of use, consistent properties and high surface quality. However, there is much to understand about prepreg prior to committing to using this material. Therefore, in this paper phenolic resin (rezolic) and two compositions, including solid epoxy resin DER633U/Hardener DEH84 and epoxy Epikote 828/Hardener Novolac have been investigated for preparing glass fiber and glass-aramid fibers reinforced prepregs. Results showed that all single resin and compositions mentioned above are satisfied technical requirements for prepregs. The best prepreg was made by composition DER633U/DEH84 because it possesses good shelf life at temperature 36-37 oC and high composite mechanical properties. For example, tensile strength 205.2 MPa and Izod impact strength 228.9 KJ/m2 with C-glass fabric reinforcement 360 g/m2

    Độ bền dai tách lớp và tính chất cơ học của vật liệu polyme compozit trên cơ sở nhựa epoxy epikote 828/OELO gia cường sợi cacbon, đóng rắn bằng xyanetyldietylentriamin

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    Carbon fabric/epoxy (CF/EP) composite toughened by OELO was prepared to improve fracture toughness of the composite. The obtained testing results showed that the Izod impact strength of carbon fabric/epoxy composites significantly increased by 31.4 % from 37.2 KJ/m2 to 48.9 KJ/m2 just by adding 6 phr (part per hundred of resin) OELO was dispersed in the epoxy matrix. Both mode-I interlaminar fracture toughness of carbon fabric/epoxy (OELO/EP) composites at crack initiation and propagation also improved by 37.2 % and 17.7 %, respectively by content of 6 phr OELO in compositions. Damaged surfaces of fractured samples were investigated using scanning electron microscopy (SEM) techniques. Results obtained from dynamic mechanical thermal analysis (DMTA) showed that the glass transition temperatures of the epoxy resin matrix were slightly reduced on the addition of 6phr OELO. Keywords. Epoxy resin, fracture toughness, epoxidized linseed oil oligomer, composite materials

    NGHIÊN CỨU SỬ DỤNG CO2 TỪ KHÍ THẢI ĐỐT THAN ĐỂ NUÔI VI TẢO SPIRULINA PLATENSIS

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    UTILIZATION OF CO2 CAPTURED FROM THE COAL-FIRED FLUE GAS FOR GROWING  SPIRULINA PLATENSIS SP4 The paper presents the results concerning the utilization of CO2 captured from the coal-fired flue gas for growing the  Spirulina platensis SP4 in laboratory condition. Several research results on the conversion of CO32- and HCO3- in algal suspension and CO2 intake efficiency by the alga were presented. The growth and  biomass quality of  Spirulina platensis SP4 using CO2 from fired-coal flue gas were equivalent to that of the alga grown in the pure CO2 experimental lot
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