Papers by Keyword: Micropowder

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Authors: Shu Ling Liu, Ai Qun Gu, Cong Li Fu, Xian Wei Yu, Mei Ju Xie, Zi Li Yu
Abstract: To explore the relationship between the properties of the PTFE micropowders and the irradiation conditions, several PTFE micropowders were prepared by electron beam irradiation from 5 to 4000 kGy in air at room temperature. The properties of the irradiated PTFEs were characterized by particle size and its distribution (PSD) determination, differential scanning calorimetric (DSC) and thermogravimetric (TG) analysis, melt flow rate (MFR) and contact angle (CA) measurements. The results indicate that the particle size, the melting and crystallization temperature (Tm and Tc) and the melt viscosity of the irradiated PTFE are lower (smaller) than those of the pristine PTFE. By linear regression, the correlation between Tm (or Tc) of the PTFE micropowder and irradiation dose is established. The variation of surface properties of the irradiated PTFE micropowder is also reported.
Authors: Jian Qing Gong, Han Ning Xiao, Zheng Yu Huang, Jiu Su Li, Jing Nie, Dan Mao
Abstract: The rheological parameters of cement pastes were investigated by varying the type and content of micropowders and the ratio of water to binder. Compressible packing model was used to calculate the packing density and to evaluate the influence of micropowders gradation on the rheological properties of fresh cement pastes. Results indicate that the higher the packing density is, the lower the yielding shear stress and plastic viscosity will be. When the ratio of water to binder is less than 0.20, the cement paste with 15% UFA and 15% SF has highest packing density and lowest yielding shear stress and plastic viscosity, which is beneficial to the workability of ultra-high performance concrete.
Authors: Jun Cong Wei, Shu Xian Liu, Hui Min Zhang, Li Xue Yu, Jun Bo Tu
Abstract: The effects of different deflocculants, fume silica, reactive micro-alumina powder and high alumina cement on the flowability of corundum based self-flowing castables were investigated using brown corundum as the main starting materials. The behavior of the castables was evaluated according to the self-flow value of the castables. The results showed that the best self-flow characteristics of corundum based self-flowing castables is obtained using sodium hexametaphosphate as deflocculant, suitable amount of alumina micropowder, fume silica, and high alumina cement as binders. The resultant castables were successfully used in the bottom of a refining ladle with capacity of 80 tons. The service life could match that of well blocks and meet the production requirements.
Authors: A. Khan, Khasan S. Karimov, M. Shah
Abstract: This work reports on the fabrication and investigation of pressure sensor based on Ag/Cu2O-PEPC-NiPc/Al composite. The active layer of the composite was deposited by drop-casting of the blend Cu2O-PEPC-NiPc on flexible substrate. The thin film of the blend consist of cuprous oxide (Cu2O) micropowder, (5 wt. %), poly-N-epoxypropylcarbazole (PEPC), (2 wt. %) and nickel phthalocyanine (NiPc) micropowder, (3 wt. %) in benzol (1 ml). The film thickness of the composite is in the range of 20-30 μm. It is found that the fabricated sensor is sensitive to pressure and showed good repeatability. The decrease in resistance of the sensor is observed 10 times by increasing the external uniaxial pressure up to 11.7 kNm-2. The experimentally obtained results are compared with the simulated results and showed reasonable agreement with each other.
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