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Kuala Lumpur, Malaysia

Wan Ghazali W.N.M.,Universiti Malaysia Pahang | Mamat R.,Universiti Malaysia Pahang | Masjuki H.H.,University MalayaKuala Lumpur | Najafi G.,Tarbiat Modares University
Renewable and Sustainable Energy Reviews | Year: 2015

Abstract This paper analyzes the performance and emissions of biodiesel from different feedstocks. The main goal of this paper is to provide information to the engineers, industrialists and researchers who are interested on biodiesel and to emphasise biodiesel as a promising alternative replacement for fossil fuels. A substantial number of literatures from highly rated journals in scientific indexes were cited preferentially since 2000. The performance and emissions indicators such as brake torque, brake power, BTE, EGT, BSFC NOx, PM, CO, CO2, HC and smoke density have been evaluated in comparison to pure diesel. The results showed that different sources of biodiesel feedstocks give different results to engine performance and emissions. Surprisingly some of the research yielded favourable results towards the biodiesel as compared to pure diesel. The study concluded that biodiesel can be used in compression ignition engine as a replacement of diesel fuel to fulfil the global energy demand. However, further research on about optimisation, cost-effectiveness and availability of biodiesel needs to be carried out to help ensure that biofuel will be able to fully replace fossil fuel. © 2015 Elsevier Ltd.

Ahmadzadeh S.,Kerman Medical University | Rezayi M.,University MalayaKuala Lumpur | Faghih-Mirzaei E.,Kerman Medical University | Yoosefian M.,Kerman Graduate University of Technology | Kassim A.,University Putra Malaysia
Electrochimica Acta | Year: 2015

A novel Ti3+ selective membrane electrode based on meso-octamethylcalix[4]pyrrole (OMCP) as an ionophore was successfully fabricated. The developed sensor revealed high selectivity towards Ti3+ ion over alkali, alkaline earth and transition metal cations. Among all of the membranes examined, the membrane with a composition of 4:33:62.8:0.2 mg of I:PVC:DOP:NaTFPB showed the best Nernstian slope of 29.49 ± 0.16 (mV per decade of activity) over the pH range from 1 to 3 with a satisfactory concentration range of 1.0 × 10-6 M to 1.0 × 10-2 M and detection limit of 8.0 × 10-7 M. The effects of various parameters such as composition of the membrane, different cation interferences and concentration of internal solution were investigated. The developed sensor exhibited a good reproducibility over a useful life time of about 3 months with a fast response time of 25 seconds. It demonstrated good analytical performance for accurate determination of Ti3+ trace amount in the presence of considerable concentration of common interfering ions. The fabricated sensor was used successfully as an indicator electrode for potentiometric titration of a titanium solution with EDTA and moreover it applied for direct determination of Ti3+ content of industrial waste water samples. The obtained results from optimized membranes were evaluated by comparing them with the data received from instrumental methods such as UV-Vis, AAS, ICP and SEM. By using density functional theory (DFT) calculations, several special adsorption sites of TiOH2+ close to OMCP are fully optimized and the best one selected. Furthermore, NBO and QTAIM analysis carried out to study the bonding strength in formed complex and deep understanding of the nature of interaction between TiOH2+ and OMCP. © 2015 Published by Elsevier Ltd.

Dominick D.,University Putra Malaysia | Latif M.T.,National University of Malaysia | Juahir H.,University Putra Malaysia | Aris A.Z.,University Putra Malaysia | Zain S.M.,University MalayaKuala Lumpur
Sustainable Environment Research | Year: 2012

This study aims to determine the influence of meteorological parameters (ambient temperature, relative humidity and wind speed) based on a daily average computation of air pollutants PM10 and NO2 at three selected stations in Malaysia, namely Shah Alam and Johor Bahru on the , and Kuching on the island of Borneo. A three-year (2007-2009) database was statistically analysed using the Pearson Correlation and Multiple Linear Regression methods. The results obtained through these analyses show that at all the three stations, NO2 has a reverse relationship with wind speed, while PM10 has a negative relationship with relative humidity and wind speed, but a positive relationship with ambient temperature. The statistical model of NO2 and PM10 including meteorological parameters highlights that among the three stations, Shah Alam Station which is located near to Kuala Lumpur city centre, is most influenced by meteorological parameters. The coefficients of determination, R2 for Shah Alam station model on NO2 and PM10 are 0.301 and 0.293 respectively. The results from this study could provide some useful input for Malaysian air quality management with respect to an ongoing plan to deal with increasing trend of PM10 and NO2 in the ambient air. © 2012, Chinese Institute of Environmental Engineering. All rights reserved.

Corlay N.,CNRS Natural Product Chemistry Institute | Lecso-Bornet M.,University of Paris Descartes | Leborgne E.,CNRS Natural Product Chemistry Institute | Blanchard F.,CNRS Natural Product Chemistry Institute | And 7 more authors.
Journal of Natural Products | Year: 2015

A large-scale in vitro screening of tropical plants using an antibacterial assay permitted the selection of several species with significant antibacterial activities. Bioassay-guided purification of the dichloromethane extract of the leaves of the Malaysian species Vitex vestita, led to the isolation of six new labdane-type diterpenoids, namely, 12-epivitexolide A (2), vitexolides B and C (3 and 4), vitexolide E (8), and vitexolins A and B (5 and 6), along with six known compounds, vitexolides A (1) and D (7), acuminolide (9), 3β-hydroxyanticopalic acid (10), 8α-hydroxyanticopalic acid (11), and 6α-hydroxyanticopalic acid (12). Their structures were elucidated on the basis of 1D and 2D NMR analyses and HRMS experiments. Both variable-temperature NMR spectroscopic studies and chemical modifications were performed to investigate the dynamic epimerization of the γ-hydroxybutenolide moiety of compounds 1-4. Compounds were assayed against a panel of 46 Gram-positive strains. Vitexolide A (1) exhibited the most potent antibacterial activity with minimal inhibitory concentration values ranging from 6 to 96 μM, whereas compounds 2 and 6-9 showed moderate antibacterial activity. The presence of a β-hydroxyalkyl-γ-hydroxybutenolide subunit contributed significantly to antibacterial activity. Compounds 1-4 and 6-9 showed cytotoxic activities against the HCT-116 cancer cell line (1 < IC50s < 10 μM) and human fetal lung fibroblast MRC5 cell line (1 < IC50s < 10 μM for compounds 1, 2, 7, 8, and 9). © 2015 The American Chemical Society and American Society of Pharmacognosy.

Zain N.N.M.,University MalayaKuala Lumpur | Zain N.N.M.,Universiti Sains Malaysia | Abu Bakar N.K.,University MalayaKuala Lumpur | Mohamad S.,University MalayaKuala Lumpur
Separation Science and Technology (Philadelphia) | Year: 2016

In this study, β−cyclodextrin (β−CD) was used to enhance the extraction of 2,4−dichlorophenol (2,4−DCP) from the aqueous sample in cloud point extraction (CPE) using spectrophotometric method. Several parameters have been investigated with and without the presence of β−CD modifier, such as pH, equilibration temperature, analyte concentration, and water content in the CPE and CPE−βCD systems, respectively. Equilibrium data are described by the Langmuir isotherm in both CPE systems with and without β−CD modifier. The thermodynamic parameters (positive values of ΔH° and ΔS°, negative values of ΔG°) indicate that the solubilization of 2,4−DCP in a polyethylene glycol silicone surfactant (DC193C) is endothermic, entropy gained, and spontaneous in both systems. In the CPE−βCD system, the results show that the β−CD modifier is capable of enhancing the extraction of 2,4−DCP pollutant from aqueous samples. © 2016 Taylor & Francis.

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