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Selangor, Malaysia

Mosorov V.,Technical University of Lodz | Abdullah J.,Malaysian Nuclear Agency
Applied Radiation and Isotopes | Year: 2011

Radioactive particle tracking techniques have been widely applied in the field of chemical engineering, especially in hydrodynamics in multiphase reactors. In classical approach, the phenomenological model is used to simulate the number of counts measured by the detector and then the tracer position is reconstructed by solving a minimisation problem between the measured events and the mentioned model. The paper presents an original algorithm for reconstruction of the tracer position during the radioactive particle tracking based on the Monte Carlo N-Particle code version 5. The validation of the proposed algorithm is evaluated for two cases: 'ideal' and physically realistic. The advantages of the new algorithm are demonstrated. © 2011 Elsevier Ltd. Source

Halib N.,Malaysian Nuclear Agency | Amin M.C.I.M.,National University of Malaysia | Ahmad I.,National University of Malaysia
Journal of Applied Polymer Science | Year: 2010

The formation and swelling behavior of bacterial cellulose/acrylic acid hydrogel prepared from aqueous mixture consists of 20 : 80 (v/v) acrylic acid (AAc) and 1% bacterial cellulose dispersion under accelerated electron beam was investigated. Gel fraction of hydrogel increased with the increasing dose suggesting a denser composite at 50 kGy compared to 35 kGy. SEM photomicrographs revealed a homogenous pores distribution at higher dose with pore sizes ranging from 1 to 5 lm. Hydrogel synthesized at lower dose of electron beam exhibited higher swelling ability and the degree of swelling increased as the pH of surrounding medium increased and it reached the optimum swelling at pH 7. While swelling of the hydrogel decreased with the increasing ionic strength of solution, swelling at different temperatures ranging from 25 to 50°C revealed a unique character where the hydrogel shrunk at 37°C. Moreover, hydrogel synthesized at higher dose exhibited a higher degree of swelling in methanol with respect to water. © 2010 Wiley Periodicals, Inc. Source

Rabir M.H.,Malaysian Nuclear Agency
Nuclear Engineering and Design | Year: 2013

This paper presents the experimental results of the power and temperature coefficients of reactivity of the RTP TRIGA reactor at the Malaysian Nuclear Agency. The power coefficient of reactivity obtained was approximately -0.26 ¢ kW-1 (-1.81 × 10-5 kW-1), and the measured temperature reactivity coefficient of the reactor was -0.82 ¢ C-1 (-5.77 × 10-5 C-1) and -1.15 ¢ C-1 (-8.08 × 10-5 C-1) in IFE C12 and IFE F16, respectively. The power defect, which is the change in reactivity taking place between zero power and the power of 850 kW was ∼2.19 $. Because of the negative temperature coefficient, a significant amount of reactivity is needed to compensate for the temperature change and allows the reactor to operate at the higher power levels in steady state. Throughout this experiment, it is the temperature of the fuel that was measured, not the isothermal temperature coefficient (ITC), which comprises both moderator and fuel. © 2013 Elsevier B.V. Source

Mohd Amin M.C.I.,National University of Malaysia | Ahmad N.,National University of Malaysia | Halib N.,Malaysian Nuclear Agency | Ahmad I.,National University of Malaysia
Carbohydrate Polymers | Year: 2012

To assist in identifying the utility of novel materials in drug-delivery applications, this study investigated the use of bacterial cellulose (BC), a natural biopolymer, in the synthesis of hydrogels for drug-delivery systems. BC was combined with different proportions of acrylic acid (AA) to fabricate hydrogels by exposure to accelerated electron-beam irradiation at different doses. Fourier transform infrared analysis revealed that the AA had been successfully grafted onto the cellulose fibers and allowed for prediction of the reaction mechanism in the synthesis of hydrogels. Thermal and morphological characterization indicated the formation of thermally stable hydrogels with pore size determined by AA content and irradiation dose. The results of swelling and in vitro drug-release studies revealed the hydrogels to be both thermo- and pH-responsive. Such thermo- and pH-responsiveness, in addition to their morphological characteristics, suggests that these BC/AA hydrogels are promising candidates as controlled drug-delivery systems. © 2011 Elsevier Ltd. All rights reserved. Source

Ling A.P.K.,International Medical University | Tan K.P.,University Tunku Abdul Rahman | Hussein S.,Malaysian Nuclear Agency
Journal of Zhejiang University: Science B | Year: 2013

Objective: Labisia pumila var. alata, commonly known as 'Kacip Fatimah' or 'Selusuh Fatimah' in Southeast Asia, is traditionally used by members of the Malay community because of its post-partum medicinal properties. Its various pharmaceutical applications cause an excessive harvesting and lead to serious shortage in natural habitat. Thus, this in vitro propagation study investigated the effects of different plant growth regulators (PGRs) on in vitro leaf and stem explants of L. pumila. Methods: The capabilities of callus, shoot, and root formation were evaluated by culturing both explants on Murashige and Skoog (MS) medium supplemented with various PGRs at the concentrations of 0, 1, 3, 5, and 7 mg/L. Results: Medium supplemented with 3 mg/L indole-3-butyric acid (IBA) showed the optimal callogenesis from both leaf and stem explants with (72.34±19.55)% and (70.40±14.14)% efficacy, respectively. IBA was also found to be the most efficient PGR for root induction. A total of (50.00±7.07)% and (77.78±16.47)% of root formation were obtained from the in vitro stem and leaf explants after being cultured for (26.5±5.0) and (30.0±8.5) d in the medium supplemented with 1 and 3 mg/L of IBA, respectively. Shoot formation was only observed in stem explant, with the maximum percentage of formation ((100.00±0.00)%) that was obtained in 1 mg/L zeatin after (11.0±2.8) d of culture. Conclusions: Callus, roots, and shoots can be induced from in vitro leaf and stem explants of L. pumila through the manipulation of types and concentrations of PGRs. © 2013 Zhejiang University and Springer-Verlag Berlin Heidelberg. Source

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