Papers by Author: H.B. Senin

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Authors: W.S. Wan Nik, S.G. Eng Giap, H.H. Masjuki, H.B. Senin
Abstract: Tribological aspects of bio-oils have to be investigated before they are used as industrial fluids. In this paper rheological (fluid deformation under shear) properties of four bio-oils are presented. A Couette type viscometer was used to evaluate flow behavior of the oils at seven discrete temperatures. Commercial coconut, canola, sunflower and corn oil were used in this study. For all the oil samples, viscosities were affected by the change of shear rate and temperature. Two rheological models, temperature dependence and shear rate dependence, were used in the study. The original power law gives contradict picture of flow curves and flow parameters. Thus, modified power law model was proposed. The modified model was fitted to experimental data to obtain the flow behavior index. Arrhenius type equation was fitted to experimental data to obtain the activation energy due to different temperatures and shear rates. Evaluation of rheological properties by modified power law model indicates that these bio-oils belong to the pseudo-plastic group.
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Authors: N. Kancono, H.B. Senin
Abstract: Charge transfer complexes (CTC) can be readily introduced into materials by cohydrolysis-copolymerisation of bis-silylated ter-thiophenes as precursors with TMOS and TEOS in the presence of TCNQ. CTC formation is shown in the visible spectrum of the xerogel by the band at 850 nm characteristic of the TCNQ·- radical anion. Vibrational spectra have shown that strong vibration of C≡N bond at 2184, 2120 and 1595 cm-1 as peaks characteristics of CTC. The CTC bands are weak and the complex is easily destroyed by washing with acetone, which removes the TCNQ. The gelification effect of the charge transfer complexes on the hybrid materials of 2,5’’- bis(trime thoxysilyl)terthiophene/TCNQ/ TMOS showed that the peak with distance of more than 11.68 Å, formed by precursors and matrices, as a lamellar structure. The birefringence of xerogel BTS3T in presence of alkoxysilane showed that the value is near the detection limit of 0.1 – 0.4 x 10-3, which is weaker than BTS3T / THF with the birefringence value of 4.5 x 10-3.
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