Eisazadeh A.,University of Technology Malaysia |
Kassim K.A.,University of Technology Malaysia |
Nur H.,Ibnu Sina Institute for Fundamental Science Studies
Applied Clay Science | Year: 2012
The poor engineering properties of soils containing high amounts of clay minerals can be altered through chemical stabilization, resulting in a material suitable for geotechnical applications. The primary objective of this research was to study the time-dependent changes in the structure of lime stabilized montmorillonitic and lateritic clays using solid state nuclear magnetic resonance (SS-NMR) and Fourier transform infrared (FTIR) spectroscopy. The 29Si and 27Al MAS NMR spectra of montmorillonite dominated soils indicated that the reaction products of the attack on the tetrahedral sheets were mainly responsible for the formation of new composites that bound the soil particles together. Furthermore, the coating of iron (hydr)oxides on the surface of the laterite clay particles retarded the pozzolanic reactions. The presence of lime in the soil-stabilizer matrix was also confirmed by a new band observed in the FTIR spectra. From the geotechnical point of view, the lime treated bentonite showed the highest degree of improvement with an approximately 11-fold strength increase in comparison to the natural soil within 8-month curing periods. © 2012 Elsevier B.V.
Setiabudi H.D.,University of Technology Malaysia |
Jalil A.A.,University of Technology Malaysia |
Triwahyono S.,Ibnu Sina Institute for Fundamental Science Studies |
Triwahyono S.,University of Technology Malaysia
Journal of Catalysis | Year: 2012
The effects of iridium loading on the properties of Ir/Pt-HZSM5 and n-pentane isomerization were studied. XRD, IR, and NMR results indicated that increasing iridium loading did not much change the properties of catalysts, but eliminated the perturbed silanol groups at 3700 and 3520 cm -1, whereas IR and ESR spectroscopy confirmed that increasing iridium loading continuously decreased the permanent Lewis and Bronsted acid sites and inhibited the formation of protonic acid sites induced by hydrogen. At low iridium loading (0-0.3 wt%), cracking process proceed through dimerization-cracking step, whereas high iridium loading (0.5-2.0 wt%) reduces the contribution of dimerization-cracking step and promotes the contribution of hydrogenolysis. The excessive amount of iridium loading, with the presence of a low amount of active protonic acid sites and hydrogen gas, accelerated the hydrogenolysis process. The activity of Ir/Pt-HZSM5 was marginal in the absence of hydrogen, showing the dependence of activity on promotive effect of hydrogen. © 2012 Elsevier Inc. All rights reserved.
See H.H.,University of Basel |
See H.H.,Ibnu Sina Institute for Fundamental Science Studies |
Stratz S.,University of Basel |
Hauser P.C.,University of Basel
Journal of Chromatography A | Year: 2013
A flow-through arrangement for electrodriven extraction across a polymer inclusion membrane was developed. Sample introduction into the donor chamber was continuous, while the acceptor solution was stagnant. By adjustment of the total volume of the donor solution pumped through the cell the best compromise between enrichment factor and extraction time can be set. The enriched extract was analyzed by capillary electrophoresis with contactless conductivity detection. Membranes of 20. μm thickness were employed which consisted of 60% cellulose triacetate as base polymer, 20% o-nitrophenyl octyl ether as plasticizer, and 20% Aliquat 336. By passing through 10. mL of sample at a flow rate of 1. mL/min the model analytes glyphosate (a common herbicide) and its major metabolite aminomethylphosphonic acid could be transported from the aqueous donor solution to the aqueous acceptor solution with efficiencies >87% in 10. min at an applied voltage of 1500. V. Enrichment factors of 87 and 95 and limits of detection down to 43 and 64. pg/mL were obtained for glyphosate and aminomethylphosphonic acid, respectively. The intra- and interday reproducibilities for the extraction of the two compounds from spiked river water were about 6 and 7% respectively when new membranes were used for each experiment. For consecutive extractions of batches of river water with a single piece of membrane a deterioration of recovery by about 16% (after 20 runs) was noted, an effect not observed with purely aqueous standards. © 2013 Elsevier B.V.
Kimi M.,University of Technology Malaysia |
Yuliati L.,Ibnu Sina Institute for Fundamental Science Studies |
Shamsuddin M.,University of Technology Malaysia
Journal of Photochemistry and Photobiology A: Chemistry | Year: 2012
A series of Cu-doped Cd 0.1Zn 0.9S solid solution with various amounts of Cu dopant was successfully prepared by hydrothermal method. The properties and the photocatalytic activity of the prepared samples for hydrogen production under visible light irradiation were compared to those prepared by co-precipitation method. The Cu-doped Cd 0.1Zn 0.9S samples prepared by hydrothermal method showed both improved crystallinity and photoabsorption ability as compared to the undoped sample. On the other hand, even though Cu-doped Cd 0.1Zn 0.9S prepared by co-precipitation method also showed improved photoabsorption ability in the visible light region, the samples showed poor crystallinity compared to the undoped one. With the same amount of Cu dopant, all samples prepared by hydrothermal method were found to exhibit higher photocatalytic activity for hydrogen production than the samples prepared by co-precipitation method. It was revealed that the amount of Cu dopant, crystallinity and narrow band gap energy are important factors to obtain highly active and stable photocatalysts. © 2012 Elsevier B.V. All rights reserved.
Jalil M.A.,Ibnu Sina Institute for Fundamental Science Studies
International journal of nanomedicine | Year: 2011
BACKGROUND: A novel nanomicro syringe system was proposed for drug storage and delivery using a PANDA ring resonator and atomic buffer. A PANDA ring is a modified optical add/drop filter, named after the well known Chinese bear. In principle, the molecule/drug is trapped by the force generated by different combinations of gradient fields and scattering photons within the PANDA ring. A nanomicro needle system can be formed by optical vortices in the liquid core waveguide which can be embedded on a chip, and can be used for long-term treatment. By using intense optical vortices, the required genes/molecules can be trapped and transported dynamically to the intended destinations via the nanomicro syringe, which is available for drug delivery to target tissues, in particular tumors. The advantage of the proposed system is that by confining the treatment area, the effect can be decreased. The use of different optical vortices for therapeutic efficiency is also discussed.