June 2008

Study on the morphology of polyacrylamide – silica fumed nanocomposite thin films

Silica fumed nanoparticles were dispersed in polyacrylamide thin films by direct mixing. Atomic Force Microscopy study was carried out in order to analyze the surface roughness. Height distribution of surface roughness changes from Gaussian like for polyacrylamide to skew asymmetric when increasing the silica concentration. The length of the distribution tail increases, indicating the formation of multi-scale features...

Author(s): Mukhles Sowwan, Maryam Faroun, Ishaq Musa, Imad Ibrahim, Sami Makharza, Wadie Sultan and Hasan Dweik

June 2008

Electronically tunable current mode second order high pass filter for different value of Q

This paper presents realization of current-mode active-R filter in order to increase the speed of circuits for analog signal processing and to decrease the supply voltages of integrated circuits. The proposed filter is constructed using operational amplifiers [OA] and resistors. The circuit capable of realizing  quadratic transfer function .The proposed second order high pass filter circuit works ideal for Q >=1...

Author(s): G. N. Shinde and D. D. Mulajkar

June 2008

Application of geochemical parameters for characterization of oil samples using GC-MS technique

Geochemical characterization of eleven (11) oil samples has been carried out; using diagnostic biomarker parameters related to thermal maturity, organic matter source, age and depositional environment. Oleanane was only found in the Nigerian oil, serving as a primary feature in distinguishing it from other oils. All the oil samples appeared to have mixed organic matter input with samples of the same region closely...

Author(s): Idris, H. K., Salihu, A.,  Abdulkadir, I. and Almustapha, M. N.

June 2008

Friedelanone and other triterpenoids from Hymenocardia acida

The stem barks of the plant Hymenocardia acida Tul. (Hymenocardiaceae) has yielded five triterpenoids which were identified by spectroscopic methods as friedelan-3-one, betulinic acid, lupeol, β-sitosterol, stigmasterol and the fatty acid, oleic acid. These compounds are being reported for this plant material for the first time.   Key words: Hymenocardia acida, hymenocardiaceae, Nigeria,...

Author(s): Igoli, O. John and Gray I. Alexander