Bismuth oxide nanoparticles (Bi2O3 NPs) have gained a spot in the development of novel molecular
probes for in vivo biomedical imaging. It exists in six polymorphic forms and each of them exerts with
different stabilities according to its synthetisation temperature. The aim of this preliminary study is to
determine effect of different synthetiation temperatures on cellular viability in vitro. One hundred µg/ml
Bi2O3 NPs synthesised at 60, 90 and 120°C were characterised using scanning electron microscope (SEM)
and their cytotoxicity was evaluated using cell viability assay (MTT assay) upon 24 hours exposure to
Chang liver cells. Images captured by SEM showed an average diameter of 300 nm monoclinic-shaped
with high crystalline formation of all three Bi2O3 NPs. MTT assay revealed increase in liver cell viability
as the synthetisation temperature of Bi2O3 NPs increase. The outcomes suggested that synthetisation
temperature of Bi2O3 NPs plays a role in cellular viability, hence predictive to the biocompatibility of
these nanoparticles to be applied as in vivo radiographic contrast medium.
A novel nitrogen-sulphur macrocyclic Schiff base, 4,11,20,27-tetrathioxo3,12,19,28-tetrathia-5,6,9,10,21,22,25,26-octaazatricyclo[28.2.2.214,17]hexatriaconta 1(33),6,8,14(36),15,17(35),22,24,30(34),31-decaene-2,13,18,29-tetraone (TGSB) derived from terephthaloyl-bis-dithiocarbazate (TDTC) and glyoxal (ethane-1,2-dione) is synthesised via condensation. Metal complexes are formed by reacting the Schiff base with various metal salts such as Ru(III), Mo(V), Cd(II), Zn(II) and Cu(II). The complexes are expected to have a general formula of M2L or M3L with a square planar or square pyramidal geometry. These compounds were characterised by various physicochemical and spectroscopic techniques. From the data, it is concluded that the azomethine nitrogen atom and the thiolate sulphur atom from the ligand are bonded to the metal ion. In the IR spectra of the complexes, the presence of the C=N band in the region of 1600 cm-1 indicates the successful formation of the Schiff base. The structures of the Schiff base and metal complexes are confirmed via FT-IR, GC-MS and NMR spectroscopic analysis. The magnetic susceptibility measurements, electronic spectral data and molar conductivity analysis support the desired geometry of the complexes. The Schiff base and its metal complexes are evaluated for their biological activities against the invasive human bladder carcinoma cell line (EJ-28) and the minimuminvasive human bladder carcinoma cell line (RT-112). The RuTGSB and CdTGSB complexes showed selective activity against RT-112.
Covalently cross-linked nanogels were prepared via irradiation of inverse micelles that had been preparedfrom radiation crosslinkable polymer, water, oil and surfactant. A mixture of polymer, water, heptane andsodium dioctyl sulfosuccinate (AOT) at certain compositions forms inverse micelles with the size rangingfrom 2 to 8 nm. The hydrophilic head of the surfactant facilitates encapsulation of water soluble polymer.If the entrapped polymer is radiation crosslinkable, it is expected that upon irradiation, polymerizationshall take place in such small and confined space, leading to formation of nano-sized polymeric gel.Meanwhile, emulsion at 2 nm size was chosen for gamma irradiation process. The formation of thenano-sized discreet gel using irradiation of inverse micelles technique was proven at a dose as low as 5kGy to obtain nanogel sized ~ 95 nm.
Dye-sensitized solar cell (DSSC) is the third generation of thin film solar cell. In this work, carrot fruit dye was prepared and used in DSSC as a sensitizer. TiO2–ZrO2 fine binary oxide was mechanochemically prepared and made paste. TiO2–ZrO2 paste (colloidal) was deposited onto FTO/glass in two ways, i.e. as single and double coatings by rolling method. It was immersed in the carrot solution to get dyed cell. The dyed TiO2-ZrO2-FTO/glass cell was offset with the FTO/glass cell coated with adhesive carbon paste. Photovoltaic properties of prepared TiO2–ZrO2 DSSC cell were measured. Results showed that the efficiency of double coating cell was greater than that of the single coating cell. According to the fill factor from the experiments, both the DSSC cells were acceptable for industrial requirement. Hence, it can be concluded that the results obtained were acceptable in the use of cost-effective and eco-favourable dye-sensitized solar cell.
Research on the use of Jatropha curcas triglycerides as biodiesel feedstock has received worldwide attention due to its inherent characteristics. Unlike palm oil, J. curcas oil is not edible, and thus, it will not disturb the food supply. However, to the researchers' experiences with the synthesis of J. curcas, oil-based biodiesel has shown that the fuel characteristics depend largely on the type of alcohol used as the excess reactants. Transesterification reaction is chosen for this process with sodium methoxide as the catalyst. Comparison studies on the yield of esters using methanol and ethanol, as well as the impacts on the reaction rate are discussed. The effects of reaction time and molar ratio on the reaction conversion are also examined. The determination of reaction yield is based on the conversion of triglycerides into alkyl esters as the main product. The findings are described as follows: the highest percentage yield of product is attained at 96% for methanol as an excess reactant, and this is 90% when ethanol is used. The optimum conditions of parameters are achieved at 6:1 molar ratio of alcohol to triglycerides, 50 min of reaction time and reaction temperature of 65°C for methanol and 75°C for ethanol. The biodiesel properties of both ester fuels were determined according to the existing standards for biodiesel and compared to the characteristics of diesel fuel.
Palm oil-based Trimethylolpropane ester (TMP ester), with an iodine value of 66.4 g/100g, was epoxidizedto produce epoxidized TMP esters. In situ epoxidation method was used with peracetic acid to eliminatefatty acid double bonds in palm oil-based TMP ester and change it into oxirane ring. This was done toimprove the oxidative stability of trimethylolpropane ester which is a key concern limiting the usefulservice life in lubricants. The epoxidation was performed by reacting acetic acid as active oxygen carrierwith concentrated hydrogen peroxide as oxygen donor and a small amount of homogeneous catalyst(sulphuric acid). The effects of various parameters on the rate of epoxidation (such as the ratio of moleacetic acid to ethylenic unsaturation, hydrogen peroxide to ethylenic unsaturation and acetic acid moleratio, and amount of catalyst) were studied. The rate of oxidation was investigated by the percentageof oxirane oxygen analysis and iodine value.
A molecularly imprinted polymer (MIP), with the ability to bind Pb(II) ion, was prepared using the non-covalent molecular imprinting methods and evaluated as a sorbent for the Pb(II) ion uptake. 4-vinylbenzoic acid was chosen as the complexing monomer. The imprinted polymer was synthesized by radical polymerization. The template (Pb(II) ions) was removed using 0.1 M HCl. As a result, the efficient adsorption was found to occur at pH 7. The result also showed the applicability of the Langmuir model for the sorption, with the maximum sorption capacity of 204.08 μg/mg.
In this study, the new compound of thiourea derivatives were successfully synthesized, namely N-((3chlorophenyl) carbamothioyl) benzamide (T1) and N-((4-chlorophenyl) carbamothioyl) benzamide (T2). These series of thiourea compounds were prepared from the reaction of benzoyl chloride with ammonium thiocyanate to produce benzoyl isothiocyanate, then direct reaction with amines by using condensation method. Their structures were characterized on the basis elemental analysis and spectroscopic techniques namely infrared and nuclear magnetic resonance. The Infrared spectra showed the significant results of stretching vibrations of the compounds are ν(C=O), ν(C=S) and ν(C-N) at 1533.39-1671.00 cm-1, 1256.64-1261.73 cm-1 and 1144.22-1144.81 cm-1, respectively. These compounds were investigated as corrosion inhibitors on mild steel in 1M H2SO4 using linear polarization techniques. Results show the highest inhibition efficiency of T1 is 55% while for T2 is 73%. The percentage inhibition efficiency of T2 is higher than T1 due to the difference position of substituent at meta and para.
Palm Oil Fuel Ash (POFA) is a biomass produced from palm oil industries. POFA is known to contain
a high amount of silica and has been proven by XRF spectroscopy, in which the silicon dioxide content
is 72.63%. In this study, silica was synthesised from POFA. To extract the silica, POFA was fused
with alkaline agent (Na2CO3) before mixing with Cethyltrimetyl Ammonium Bromide (CTAB) and
Sulphuric Acid (H2SO4). Sodium silicate solution from the fusion was used as silica precursor replacing
conventionally used silica source, Tetraethoxilane (TEOS). XRD pattern showed that raw POFA
dominantly consists of silica. Meanwhile, FTIR analysis of the synthesised silica exhibited spectra
bands at 3393 cm-1, 1635 cm-1, 1028 cm-1 and 787 cm-1 that corresponded to the functional groups of
Si-O and O-H. Thus, it could be concluded that silica was successfully extracted from POFA by the
alkaline fusion method.
A mononuclear and new tetranuclear metal complexes of Zn(II) with Schiff base ligands L1 and L2 respectively, were synthesised. L1 was obtained through the condensation of salicylaldehyde with ortho-phenylenediamine while L2 was the product of reaction between of ortho-vanillin with 2,4,6-trimethyl-m-phenylenediamine. The ligands and complexes were characterised via elemental analysis, melting point, IR and NMR spectroscopy. The shifting of v(C=N), v(C-OH) and v(O-CH3) infrared peaks upon coordination with Zn(II) indicated that these three moieties play a significant role in the complexation. It was found that L1 acted as tetradentate ligand, coordinating with Zn(II) centres through phenolic oxygen and imine nitrogen. The ligand L2 acted as a hexadentate ligand, bonded to metal via phenolic oxygen, imine nitrogen and methoxy oxygen, where four Zn(II) centres formed bridges to connect two ligands.
A new series of N,O-bidentate ligands, L1, L2, L3 and L4, and their Pd(II) complexes, PdL1, PdL2, PdL3
and PdL4 have been synthesised and characterised using various physico-chemical techniques, namely
elemental analyses, IR and 1
H and 13C NMR spectroscopies, and conductivity analysis. The molecular
geometries of PdL2 and PdL4 have been elucidated through single crystal X-ray crystallography revealing
2:1 molar equivalence of ligand: Pd with the Schiff bases that exhibited bidentate ligands behaviour,
in which they coordinated through the phenolic O donor atoms and imine N. Upon complexation, the
ν(C=N) around 1629-1639 cm-1 and ν(C-O) around 1251 to 1252 cm-1 shifted to lower frequencies by 4
to 23 cm-1. In this study, three parameters were chosen for the reaction conditions optimisation, which
were types of bases, loadings for the catalyst, and temperatures of the reaction. Pd(II) complexes exhibited
good catalytic activities for Heck coupling reaction with 100% conversion at 100°C within 12 hours of
reaction time. Reducing the reaction temperature to 80°C reduced the conversion to a maximum of 80%.
This research presents compensation of current harmonic disturbance in power system network using
shunt active power filter. In this paper, harmonic extraction using Synchronous Reference Frame
Fundamental technique (SRFF) was investigated for three phase 3-wire system. It proposes a method
based on direct current measurement of load currents using a band pass filter at low cut off frequencies
to improve the filtering ability in highly contaminated loads. The proposed filter consists of second
order low pass and high pass filters cascaded together at suitable frequencies, estimated based on the
output of these units to mitigate the current harmonics. The performance of the system was simulated
in Matlab Platform and evaluated considering total harmonic distortion of the source current in a threephase
balanced network. The simulation results show the ability of the proposed tracking scheme to
accurately estimate harmonics.
A new smart grid system is widely used for energy supply system because it is simple, available, low cost, high efficiency and environmentally friendly. Conventionally, inverter techniques are utilised to convert input DC into output AC with the same frequency and phase. This process suffers the same problem which is a higher harmonic distortion, phase synchronisation, lower quality of waveform and long distance, among others. In this paper, three phase synchronous inverters (PSI) were used to direct synchronous PWM control, LCL filter, three phase RLC load, three phase Yg-Delta transformer, 5 km feeder with 2 MW load. PWM was used to generate the pulse signal for synchronisation. However, LCL filters were used to remove the noise in inverter output and transformer output side of the design. A balanced three phase load (10 kVAR) and also the input DC voltage 500 V were considered in this design. Three phase transformer (100kVA/260V/25kV) was used to increase the inverter output voltage and current with the fundamental frequency (50 Hz). The system conversion efficiency was 99.96% and phase synchronous error for each phase was approximately 4.5 degrees.
Two different supercapacitor configurations were fabricated using coconut shell-based activated
carbon. Results for cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and charge-discharge measurements are presented and discussed for both configurations. The results show that coconut shell-based activated carbon is viable economical alternative electrode material to expensive activated carbon (AC) and carbon nano tubes (CNT). Meanwhile, the calculations from the charge-discharge characteristics show that the disk-shape supercapacitor, with 10% polyvinylidene fluoride binder (PVdF), has the highest specific capacitance (70F/g). Thus, the testing shows that the flat-laminated super-capacitor with 10% binder (PVdF) has the lowest (10.1ohms). Sources of high equivalent series resistance (ESR) are proposed and methods of reducing it are also discussed in this paper.
Sustainability is an important factor in designing vernacular architecture, including vernacular palace architecture; the latter refers to low-rise buildings similar to Traditional Malay Houses (TMH). However, the Istana Lama Seri Menanti is a 4-storey mid-rise vernacular palace which was designed with sustainability in mind. This mid-rise element of the palace communicates the vernacular architecture of TMH in Negeri Sembilan whereas sustainable designs are factored in environmentally friendly materials, construction methods, and the environmental impact of the building culturally and economically. This research was aimed at examining the sustainability approach of Istana Lama Seri Menanti as a mid-rise vernacular palace in the early 20th Century, and its impact on the current generation after 109 years. The research methodologies include case and precedent studies of vernacular palaces in Malaysia as well as interviews with experts in the field. In conclusion, the architectural sustainability of Istana Lama Seri Menanti had taken into account timber availability, consumption of naturally available resources, designs with minimal environmental impact and high cultural importance in the building design with the ultimate aim of conserving it for future generations.
Clinacanthus nutans, known to the locals as Belalai Gajah, is a medicinal plant widely used by Malaysians in the belief to cure various diseases including cancer. However, the production of Belalai Gajah hardly fulfils the market demand since the growing techniques of stem cutting and tissue culture are inefficient and expensive. Therefore, improvements in tissue culture techniques and materials application are required. Hence, this study tested Carica papaya (locally know as papaya) stem, an agricultural waste, to enhance the tissue culture of C. nutans. The effects of C. papaya stem powder and extract on the shoot proliferation of C. nutans parameters were investigated. The average number of shoot, leaves and length of leaves were observed. Phytochemicals screening was also conducted. Overall, C. papaya stem extract showed positive performance and 1% extract was found to be the optimum concentration to enhance the shoot proliferation. Meanwhile, C. papaya stem powder inhibited the shoot proliferation. It was also found that flavonoids, glycosides, steroid and terpenoid contributed in the shoot proliferation. In conclusion, the papaya stem extract is a potential in-vitro supplement for tissue culture studies. This study gained insights in sustainable green economy and showed that zero waste can be attained by converting local papaya stem waste to valuable product. In addition, sustainable technology in pharmaceutical approach could be addressed through in-vitro low cost large-scale production of Belalai Gajah medicinal plant.
Ultraviolet radiation is at shorter wavelengths than the visible spectrum (400 to 700 nm) and is divided into three components: UV-A (315 to 400 nm), UV-B (280 to 315 nm), and UV-C (less than 280 nm). Global increases in UV-B fluxes from decreasing stratospheric ozone amounts caused by anthropogenic chlorine releasing gases (mostly chlorofluorocarbons) have been a matter of public concern for the past 20 years. This surface UV irradiance data retrieved from Ozone Monitoring Instrument (OMI) from AURA spacecraft with the filename OMUVB. OMUVB contains surface UV irradiance data along with supplementary information generated using the OMI global mode measurements. In this mode each file contains the sunlit portion of a single orbit from pole-to-pole, with an approximately 2600 km wide swath composed of 60 ground pixels. The OMI measurements are used to estimate the ultraviolet (UV) radiation reaching the Earth’s surface. The product contains spectral irradiances at 305.1, 310.1, 324.1, and 380.1 nm corresponding to both the overpass time and the local solar noon. Using the correspondence latitude and longitude of Peninsular Malaysia, we can develop the pattern of distribution of UV irradiance interpolations using Sigma Plot and Adobe Photoshop.
Chemical industries are greatly assisted by catalysts; and commonly used catalysts for C-C formation
reactions are mainly phosphine-based complexes which are air and moisture sensitive. New air stable
Schiff base Pd(II) complexes have been synthesised, characterised and screened for their catalytic potential.
This paper reports three ONNO Schiff bases, namely, L2C [2,2’-((1E,1’E)-((2,2-dimethylpropane-1,3-
diyl) bis (azanylylidene)) bis (methanylylidene)-) bis (4-chlorophenol)], L2M [2,2’-((1E,1’E)-((2,2-
dimethylpropane-1,3-diyl)bis(azanylyli-dene)) bis (methanylylidene)) bis (4-methylphenol)] and L2H
[2,2’-((1E,1’E) - ((2,2-dimethyl-propane-1,3-diyl) bis (azanylylidene)) bis (methanylylidene)) diphenol].
These were synthesised from 2,2-dimethyl-1,3-propanediamine and salicylaldehyde derivatives with Cl,
CH3 and H at the meta position, respectively. The compounds were reacted with palladium(II) acetate
yielding three palladium(II) complexes denoted as PdL2C, PdL2M and PdL2H. The structures of all
compounds were elucidated through elemental analysis, 1
H and 13C NMR, FTIR and melting point. The
complexes were screened for catalytic activities in Sonogashira coupling reaction between iodobenzene
and phenylacetylene in DMSO. PdL2H was found to be the most active catalyst with 87% iodobenzene
conversion after 12 hours of reaction.
This study compares the distribution of dissolved nutrients (NO3 − and PO4 3−) between two seasons (pre-monsoon and post-monsoon) in Pulau Perhentian, Terengganu. The concentration of dissolved PO4 3− was found to be 16 to 83 times higher during the postmonsoon period (April 2015) compared to the pre-monsoon period (October 2014). On the other hand, the concentration of dissolved NO3 − was two (2) to three (3) times higher during the post-monsoon period (April 2015) compared to the pre-monsoon period (October 2014). These nutrients’ inputs were converted from P limitation condition during the premonsoon period to N limitation condition during the post-monsoon period at our study area. The results of this study suggest that the Northeast monsoon plays an important role in influencing the distribution of dissolved nutrients between seasons in Pulau Perhentian. It is thought that during the post-monsoon period, a considerable input of nutrients from bottom water is responsible for increasing dissolved nutrients in surface water, in particular PO4 3−.
An in-house quasi-dimensional code has been developed which simulate the overlap, intake, compression, combustion, as well as expansion and exhaust processes of a homogeneous charged internal combustion engine (ICE). A detailed chemical kinetic mechanism, constituting of 39 species and 148 elementary reactions, has been used in conjunction with above code to study the combustion of CNG under IC engine conditions. Two different criteria, based on pressure rise and mass of fuel burned, are used to detect the onset of ignition. Parametric studies are conducted to show the effect of compression ratio, initial pressure, intake temperature and equivalence ratio, on the time of ignition and fuel burning rate. The results obtained from the modelling show a good agreement with the experimental data.