The aim of this study was to investigate and apply supported ionic liquid membrane (SILM) in two-... more The aim of this study was to investigate and apply supported ionic liquid membrane (SILM) in two-phase micro-electrodriven membrane extraction combined with high performance liquid chromatography-ultraviolet detection (HPLC-UV) for pre-concentration and determination of three selected antidepressant drugs in water samples. A thin agarose film impregnated with 1-hexyl-3-methylimidazolium hexafluorophosphate, [C6MIM] [PF6], was prepared and used as supported ionic liquid membrane between aqueous sample solution and acceptor phase for extraction of imipramine, amitriptyline and chlorpromazine. Under the optimized extraction conditions, the method provided good linearity in the range of 1.0-1000μgL(-1), good coefficients of determination (r(2)=0.9974-0.9992) and low limits of detection (0.1-0.4μgL(-1)). The method showed high enrichment factors in the range of 110-150 and high relative recoveries in the range of 88.2-111.4% and 90.9-107.0%, for river water and tap water samples, respectively with RSDs of ≤7.6 (n=3). This method was successfully applied to the determination of the drugs in river and tap water samples. It is envisaged that the SILM improved the perm-selectivity by providing a pathway for targeted analytes which resulted in rapid extraction with high degree of selectivity and high enrichment factor.
... Tun Hussein Onn Malaysia 86400 Parit Raja, Batu Pahat, Johor E-mail addresses: e-mail: amtra... more ... Tun Hussein Onn Malaysia 86400 Parit Raja, Batu Pahat, Johor E-mail addresses: e-mail: amtra@uthm.edu.my ('Amira Saryati Ameruddin) ... YI, ZM Wang, and GJ Salamo, Investigation of inditim distribution in InGaAs/GaAs quantum dots stacks using high resolution x-ray ...
Stacked InxGa1-xAs quantum dots (QDs) were grown by metal-organic chemical vapor deposition (MOCV... more Stacked InxGa1-xAs quantum dots (QDs) were grown by metal-organic chemical vapor deposition (MOCVD) via Stranski -Krastanov growth mode. AFM images show that the QDs structures were formed and the stacked structure of InxGa1-xAs QDs were confirmed by the HR-XRD analysis. Composition of the dots on the top most layers was related to the number of stack layers. The observed PL
Hussin, Salwa and Shahir, Shafinaz and Ismail, Abd. Khamim (2009) A locally developed microbial c... more Hussin, Salwa and Shahir, Shafinaz and Ismail, Abd. Khamim (2009) A locally developed microbial consortium for short-term biochemical oxygen demand (BODst) sensing. In: International Congress of Malaysian Society for Microbiology (ICMSM 2009) , 2009, Hotel Parkroyal, P. Pinang. ... Full text not available from this repository. ... Universiti Teknologi Malaysia Institutional Repository is powered by EPrints 3 which is developed by the School of Electronics and Computer Science at the University of Southampton. More information and software credits.
ABSTRACT Single layer of In0.5Ga0.5As quantum dots (QDs) was grown using self-assembled Stranski-... more ABSTRACT Single layer of In0.5Ga0.5As quantum dots (QDs) was grown using self-assembled Stranski-Krastanow on a thin InxGa1−xAs underlying layer and on a reference GaAs wafer by metal-organic chemical vapour deposition (MOCVD). The effect of different indium composition in the underlying layer and the duration of arsine (AsH3) flow during cooling-down period of the growth process were investigated and characterized using atomic force microscopy (AFM). The growth of the thin underlying layer has significant influence on the formation of the QDs on the top surface. The dots density increases with increasing indium composition in the underlying layer. AsH3 flow during the period was found to influence the nucleation process of In0.5Ga0.5As QDs. A shorter period of AsH3 flow promotes smaller dots size and therefore increases the dots density.
Journal of Micromechanics and Microengineering, Jan 8, 2008
This paper presents a discussion on the fabrication, characterization and testing of a degenerate... more This paper presents a discussion on the fabrication, characterization and testing of a degenerate mode resonant mass sensor which takes the form of a crystalline silicon MEMS circular diaphragm. The device is fabricated from the device layer of a SOI wafer which is ...
Perceptual decision making depends on the choices available for the presented task. Most event-re... more Perceptual decision making depends on the choices available for the presented task. Most event-related potential (ERP) experiments are designed with two options, such as YES or NO. In some cases, however, subjects may become confused about the presented task in such a way that they cannot provide a behavioral response. This study aims to put subjects into such a puzzled state in order to address the following questions: How does the brain respond during puzzling moments? And what is the brain’s response to a non-answerable task? To address these questions, ERP were acquired from the brain during a scintillation grid illusion task. The subjects were required to count the number of illusory dots, a task that was impossible to perform. The results showed the presence of N130 over the parietal area during the puzzling task. Coherency among the brain hemispheres was enhanced with the complexity of the task. The neural generators’ source localizations were projected to a multimodal comple...
Achieving two dimensional quantum structure of silicon with well-defined tunable morphology is an... more Achieving two dimensional quantum structure of silicon with well-defined tunable morphology is an outstanding issue. We present the preliminary results on fabrication parameters dependent silicon thin film production using VHF-PECVD method. Five samples are prepared on Si(100) substrate with gold (Au) catalyst by adjusting different parameters such as deposition time, temperature and the flow of precursor gas. The samples morphology are analyzed using FESEM. The results reveal that the silicon thin film appear to be smooth and more uniform after an enormous amount of hydrogen is inserted together with the precursor gas (silane) during the deposition process. More interestingly, the films exhibit silicon nanowires as the deposition time is increased up to 1 hour. This morphological transformation is attributed to the vapor-liquid-solid (VLS) mechanism related to the deposition process.
In the present work the performance of orthogonal and Biorthogonal wavelet filters were analyzed ... more In the present work the performance of orthogonal and Biorthogonal wavelet filters were analyzed for visual evoked potentials (VEP) on a variety of noisy signals. The signals were analyzed at different signal to noise ratio (SNR). This research proposed a method for the selection of the best analysis. The proposed method used longest common subsequence (LCS) and basic local alignment search tool (BLAST) to measure the analysis performance objectively and visual quality subjectively of the signal analysis. It was found that orthogonal wavelets outperform the biorthogonal ones in both the criteria especially at high noisy signal.
Visual evoked potential (VEPs) is an electrical potential recorded from the nervous system of a h... more Visual evoked potential (VEPs) is an electrical potential recorded from the nervous system of a human brain following presentation of a visual stimulus; differ than spontaneous potentials as detected by electroencephalography (EEG). Visual evoked potentials (VEPs) is very weak and sensitive signals implemented in the wideband ongoing electroencephalogram (EEG) signals which considered as a noise in a time locked signals. To get clear and readable signals, special processing filter should be used in order to reduce the level of noise and unwanted signal. Wavelet filter is a preferable filter due to its space localization which based on time-scale representation. Different types of function can be used as a mother wavelet; this study concentrates on multiresolution analysis of Daubechies, Symlet and Coiflet wavelets in its discrete form to analyze VEP signals in such a comparative way and to find the best analysis of VEP window.
ABSTRACT An effective ferricyanide-mediated microbial biochemical oxygen demand (BOD) biosensor w... more ABSTRACT An effective ferricyanide-mediated microbial biochemical oxygen demand (BOD) biosensor was constructed and used for BOD determination in a water system. This BOD sensor uses ultramicroelectrode (UME) technology in which the tip of the sensor consists of a two-electrode system (10-μm Pt working electrode and Pt counter electrode). Because of their small size, UMEs have relatively large diffusion layers and small overall currents enabling rapid achievement of useful steady-state conditions with very high scan rates. Living Chromobacterium violaceum R1 cells (isolated from pineapple industry wastewater) were immobilized on the surface of the UME working electrode using a calcium alginate gel and further enclosure by a layer of polyamide membrane. Glucose-glutamic acid (GGA) solution was used as the standard solution. The amperometric measurement was optimized at +450 mV operating potential and 30 mM ferricyanide in a 0.1 M phosphate buffer (pH 7.0) at 26 °C. The sensor exhibited a linear response ranging from 20 to 225 mg O2 L−1 BOD5 for standard GGA solution and 25 to 230 mg O2 L−1 BOD5 for OECD synthetic wastewater with a response time of 30 min. Repeatability and reproducibility of the biosensor were within the limits set by the APHA; i.e., less than 15.4%. The rapid BOD estimation of the biosensor is applicable for measuring samples with a high content of fast and easily assimilated compounds. When used to estimate the BOD of various wastewaters, the developed biosensor provided values comparable to those obtained using the conventional BOD5 method.
Carbon doped aluminum oxide co-doped with magnesium (Al2O3:C:Mg) thin films were deposited using ... more Carbon doped aluminum oxide co-doped with magnesium (Al2O3:C:Mg) thin films were deposited using radio frequency magnetron sputtering method on Si (100) substrates. The deposition chamber temperature was manipulated to allow control over the crystalline phase. The crystalline phase of deposited thin films were determined by x-ray diffraction (XRD) technique. Slight change in crystallite size was observed with respect to the increasing deposition chamber temperature. Fourier transform infrared (FTIR) analyses indicated a negligible interfacial SiO2 growth during deposition. Transmission spectra of FTIR showed the bond and functional group of deposited thin films.
The aim of this study was to investigate and apply supported ionic liquid membrane (SILM) in two-... more The aim of this study was to investigate and apply supported ionic liquid membrane (SILM) in two-phase micro-electrodriven membrane extraction combined with high performance liquid chromatography-ultraviolet detection (HPLC-UV) for pre-concentration and determination of three selected antidepressant drugs in water samples. A thin agarose film impregnated with 1-hexyl-3-methylimidazolium hexafluorophosphate, [C6MIM] [PF6], was prepared and used as supported ionic liquid membrane between aqueous sample solution and acceptor phase for extraction of imipramine, amitriptyline and chlorpromazine. Under the optimized extraction conditions, the method provided good linearity in the range of 1.0-1000μgL(-1), good coefficients of determination (r(2)=0.9974-0.9992) and low limits of detection (0.1-0.4μgL(-1)). The method showed high enrichment factors in the range of 110-150 and high relative recoveries in the range of 88.2-111.4% and 90.9-107.0%, for river water and tap water samples, respectively with RSDs of ≤7.6 (n=3). This method was successfully applied to the determination of the drugs in river and tap water samples. It is envisaged that the SILM improved the perm-selectivity by providing a pathway for targeted analytes which resulted in rapid extraction with high degree of selectivity and high enrichment factor.
... Tun Hussein Onn Malaysia 86400 Parit Raja, Batu Pahat, Johor E-mail addresses: e-mail: amtra... more ... Tun Hussein Onn Malaysia 86400 Parit Raja, Batu Pahat, Johor E-mail addresses: e-mail: amtra@uthm.edu.my ('Amira Saryati Ameruddin) ... YI, ZM Wang, and GJ Salamo, Investigation of inditim distribution in InGaAs/GaAs quantum dots stacks using high resolution x-ray ...
Stacked InxGa1-xAs quantum dots (QDs) were grown by metal-organic chemical vapor deposition (MOCV... more Stacked InxGa1-xAs quantum dots (QDs) were grown by metal-organic chemical vapor deposition (MOCVD) via Stranski -Krastanov growth mode. AFM images show that the QDs structures were formed and the stacked structure of InxGa1-xAs QDs were confirmed by the HR-XRD analysis. Composition of the dots on the top most layers was related to the number of stack layers. The observed PL
Hussin, Salwa and Shahir, Shafinaz and Ismail, Abd. Khamim (2009) A locally developed microbial c... more Hussin, Salwa and Shahir, Shafinaz and Ismail, Abd. Khamim (2009) A locally developed microbial consortium for short-term biochemical oxygen demand (BODst) sensing. In: International Congress of Malaysian Society for Microbiology (ICMSM 2009) , 2009, Hotel Parkroyal, P. Pinang. ... Full text not available from this repository. ... Universiti Teknologi Malaysia Institutional Repository is powered by EPrints 3 which is developed by the School of Electronics and Computer Science at the University of Southampton. More information and software credits.
ABSTRACT Single layer of In0.5Ga0.5As quantum dots (QDs) was grown using self-assembled Stranski-... more ABSTRACT Single layer of In0.5Ga0.5As quantum dots (QDs) was grown using self-assembled Stranski-Krastanow on a thin InxGa1−xAs underlying layer and on a reference GaAs wafer by metal-organic chemical vapour deposition (MOCVD). The effect of different indium composition in the underlying layer and the duration of arsine (AsH3) flow during cooling-down period of the growth process were investigated and characterized using atomic force microscopy (AFM). The growth of the thin underlying layer has significant influence on the formation of the QDs on the top surface. The dots density increases with increasing indium composition in the underlying layer. AsH3 flow during the period was found to influence the nucleation process of In0.5Ga0.5As QDs. A shorter period of AsH3 flow promotes smaller dots size and therefore increases the dots density.
Journal of Micromechanics and Microengineering, Jan 8, 2008
This paper presents a discussion on the fabrication, characterization and testing of a degenerate... more This paper presents a discussion on the fabrication, characterization and testing of a degenerate mode resonant mass sensor which takes the form of a crystalline silicon MEMS circular diaphragm. The device is fabricated from the device layer of a SOI wafer which is ...
Perceptual decision making depends on the choices available for the presented task. Most event-re... more Perceptual decision making depends on the choices available for the presented task. Most event-related potential (ERP) experiments are designed with two options, such as YES or NO. In some cases, however, subjects may become confused about the presented task in such a way that they cannot provide a behavioral response. This study aims to put subjects into such a puzzled state in order to address the following questions: How does the brain respond during puzzling moments? And what is the brain’s response to a non-answerable task? To address these questions, ERP were acquired from the brain during a scintillation grid illusion task. The subjects were required to count the number of illusory dots, a task that was impossible to perform. The results showed the presence of N130 over the parietal area during the puzzling task. Coherency among the brain hemispheres was enhanced with the complexity of the task. The neural generators’ source localizations were projected to a multimodal comple...
Achieving two dimensional quantum structure of silicon with well-defined tunable morphology is an... more Achieving two dimensional quantum structure of silicon with well-defined tunable morphology is an outstanding issue. We present the preliminary results on fabrication parameters dependent silicon thin film production using VHF-PECVD method. Five samples are prepared on Si(100) substrate with gold (Au) catalyst by adjusting different parameters such as deposition time, temperature and the flow of precursor gas. The samples morphology are analyzed using FESEM. The results reveal that the silicon thin film appear to be smooth and more uniform after an enormous amount of hydrogen is inserted together with the precursor gas (silane) during the deposition process. More interestingly, the films exhibit silicon nanowires as the deposition time is increased up to 1 hour. This morphological transformation is attributed to the vapor-liquid-solid (VLS) mechanism related to the deposition process.
In the present work the performance of orthogonal and Biorthogonal wavelet filters were analyzed ... more In the present work the performance of orthogonal and Biorthogonal wavelet filters were analyzed for visual evoked potentials (VEP) on a variety of noisy signals. The signals were analyzed at different signal to noise ratio (SNR). This research proposed a method for the selection of the best analysis. The proposed method used longest common subsequence (LCS) and basic local alignment search tool (BLAST) to measure the analysis performance objectively and visual quality subjectively of the signal analysis. It was found that orthogonal wavelets outperform the biorthogonal ones in both the criteria especially at high noisy signal.
Visual evoked potential (VEPs) is an electrical potential recorded from the nervous system of a h... more Visual evoked potential (VEPs) is an electrical potential recorded from the nervous system of a human brain following presentation of a visual stimulus; differ than spontaneous potentials as detected by electroencephalography (EEG). Visual evoked potentials (VEPs) is very weak and sensitive signals implemented in the wideband ongoing electroencephalogram (EEG) signals which considered as a noise in a time locked signals. To get clear and readable signals, special processing filter should be used in order to reduce the level of noise and unwanted signal. Wavelet filter is a preferable filter due to its space localization which based on time-scale representation. Different types of function can be used as a mother wavelet; this study concentrates on multiresolution analysis of Daubechies, Symlet and Coiflet wavelets in its discrete form to analyze VEP signals in such a comparative way and to find the best analysis of VEP window.
ABSTRACT An effective ferricyanide-mediated microbial biochemical oxygen demand (BOD) biosensor w... more ABSTRACT An effective ferricyanide-mediated microbial biochemical oxygen demand (BOD) biosensor was constructed and used for BOD determination in a water system. This BOD sensor uses ultramicroelectrode (UME) technology in which the tip of the sensor consists of a two-electrode system (10-μm Pt working electrode and Pt counter electrode). Because of their small size, UMEs have relatively large diffusion layers and small overall currents enabling rapid achievement of useful steady-state conditions with very high scan rates. Living Chromobacterium violaceum R1 cells (isolated from pineapple industry wastewater) were immobilized on the surface of the UME working electrode using a calcium alginate gel and further enclosure by a layer of polyamide membrane. Glucose-glutamic acid (GGA) solution was used as the standard solution. The amperometric measurement was optimized at +450 mV operating potential and 30 mM ferricyanide in a 0.1 M phosphate buffer (pH 7.0) at 26 °C. The sensor exhibited a linear response ranging from 20 to 225 mg O2 L−1 BOD5 for standard GGA solution and 25 to 230 mg O2 L−1 BOD5 for OECD synthetic wastewater with a response time of 30 min. Repeatability and reproducibility of the biosensor were within the limits set by the APHA; i.e., less than 15.4%. The rapid BOD estimation of the biosensor is applicable for measuring samples with a high content of fast and easily assimilated compounds. When used to estimate the BOD of various wastewaters, the developed biosensor provided values comparable to those obtained using the conventional BOD5 method.
Carbon doped aluminum oxide co-doped with magnesium (Al2O3:C:Mg) thin films were deposited using ... more Carbon doped aluminum oxide co-doped with magnesium (Al2O3:C:Mg) thin films were deposited using radio frequency magnetron sputtering method on Si (100) substrates. The deposition chamber temperature was manipulated to allow control over the crystalline phase. The crystalline phase of deposited thin films were determined by x-ray diffraction (XRD) technique. Slight change in crystallite size was observed with respect to the increasing deposition chamber temperature. Fourier transform infrared (FTIR) analyses indicated a negligible interfacial SiO2 growth during deposition. Transmission spectra of FTIR showed the bond and functional group of deposited thin films.
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