Displaying publications 1 - 20 of 181 in total

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  1. Fulltext Local oscillator parameter estimation of collaborative beamforming nodes
    Umar Suleiman Dauda, Nik Noordini Nik Abdl Malik, Mazlina Esa, Mohd Fairus Mohd Yusoff, Mohamed Rijal Hamid
    Journal of Advanced Research in Applied Sciences and Engineering Technology, 2017;6(1):1-8.
    MyJurnal
    Parameter estimation of complex exponential signals corrupted by additive white
    Gaussian noise (AWGN) is crucial in the study of distributed beamforming in a practical
    scenario. Near zero (0) phase offset are expected at the receiver end which rely on the
    smoothing and correction of the frequency and phase estimates. Neither
    computational complexity nor the processing latency has an effect on the expected
    zero phase offset but the estimation accuracy does. Thus, the maximum likelihood
    estimator (MLE) using Fast Fourier Transform (FFT) approach is being considered for
    cases with none and post processing in locating of the maximum peaks. Details on how
    the phase estimates are arrived at is not always covered in literatures but explained in
    the article. Numerical results obtained showed that global maximum peaks are arrived
    at by employing a fine search with higher values of FFT.
    Matched MeSH terms: Fourier Analysis
  2. CMF-iteMS: An automatic threshold selection for detection of copy-move forgery
    Abd Warif NB, Idris MYI, Abdul Wahab AW, Salleh R, Ismail A
    Forensic Sci Int, 2019 Feb;295:83-99.
    PMID: 30576953 DOI: 10.1016/j.forsciint.2018.12.004
    Taking into consideration that the prior CMF detection methods rely on several fixed threshold values in the filtering process, we propose an efficient CMF detection method with an automatic threshold selection, named as CMF-iteMS. The CMF-iteMS recommends a PatchMatch-based CMF detection method that adapts Fourier-Mellin Transform (FMT) as the feature extraction technique while a new automatic threshold selection based on iterative means of regions size (iteMS) procedure is introduced to have flexibility in changing the threshold value for various characteristics (quality, sizes, and attacks) in each input image. To ensure the reliability of the proposed CMF-iteMS, the method is compared with four state-of-the-art CMF detection methods based on Scale Invariant Feature Transform (SIFT), patch matching, multi-scale analysis and symmetry techniques using three available datasets that cover the variety of characteristics in CMF images. The results show that the F-score of the CMF-iteMS outperformed existing CMF detection methods by exceeding an average of 90% F-score values for image-level evaluation and 82% of F-score value for pixel-level evaluation for all datasets in original size. As special attention is given to the image resizing attack, the method is able to maintain the highest performance even if the images in the datasets are resized to 0.25 parameter.
    Matched MeSH terms: Fourier Analysis
  3. Fulltext Computational analysis of fluid flow past a bluff body at low Reynolds number in different apex angle
    Jusoh, M.Z.M., Nur Ain, A.R, Muhammad Wafi Md Nor
    ESTEEM Academic Journal, 2020;16(2):65-74.
    MyJurnal
    A computational fluid dynamic analysis (CFD) is presented in the study of low Reynolds number fluid flow moving past bluff bodies. The study is focusing on the understanding of the effects of the apex-angles orientation on the flow structure and related occurring force. The apex-angle both facing upstream and downstream were computationally investigated. The simulation results of the cylinder solid are compared with available experimental data to justify the results and the model used. Results obtained in the present work were Strouhal number, drag coefficient, and Fast Fourier Transform (FFT). The study had found that the value of the drag force is increasing directly proportional to the apex angle. In contrast, the value of Strouhal number inversely proportional to the increasing of the apex angle. This was due to the flow over a cylinder creating a vortex shedding in the wake region which influenced the flow separation of fluid. Through the changing on orientation of the apex angle, it was also found that the characteristic linear dimension of the geometry will also be changed, thus affecting the flow pattern.
    Matched MeSH terms: Fourier Analysis
  4. Study on the chemical changes of Quercus acuttisima by Ganoderma lucidum cultivation after different years by FTIR analysis
    Zhang W, Chen X, Liu G, Jin G, Li Y, Li G, et al.
    Spectrochim Acta A Mol Biomol Spectrosc, 2022 Feb 05;266:120443.
    PMID: 34619507 DOI: 10.1016/j.saa.2021.120443
    The popularmedicinal mushroomGanodermalucidum was often cultivated by the natural-log. Generally the short log after cultivation were discarded and became pollutant. Rapid and less destructive method of analysis technical by Fourier Transform Infrared (FTIR) and Two-dimension Infrared (2DIR) correlation spectroscopy were selected to determine the composition changes of the logs after G.lucidum cultivation after first year to fifth year. The FTIR accumulated spectra formed without processed baseline showed the samples relied upon a sequenced increase of higher level than spectrum control Q (Q = Quercus acuttisima) from L + Q-5 (L = Lingzhi), L + Q-3, L + Q-1 to L + Q-2. The spectrum L + Q-4 has the optimum highest peak at box B, C and E from this lumped spectral view. The split spectra pinpointed on the fingerprint region of a sample begins from peak 1737 cm-1. ascribed C = O stretching vibration on acetyl and carboxyl hemicellulose group bonding gradually faded from L + Q-1 to L + Q-4 but appeared again on L + Q-5, possibly due to the degradation of hemicellulose. The absorption of peak around 1626 cm-1,1318 cm-1 and 781 cm-1 could be the characteristic absorption peak of calcium oxalate monohydrate. The correlation table indicated, most of the original structure of the building block of the wooden part was deteriorated and marked the lowest correlation value of the 4th year sample with control Q. The sudden changing pattern of 2nd derivative spectrum L + Q-3 to more flatten pattern spectrum L + Q-4 ascribed the changing contents of cellulose and hemicellulose included the lignin within one year during the G. lucidum cultivation. The 2DIR spectrum of the raw material sample precisely showed that the active site with red color was clustered with the area around 1800-1700 cm-1, 1450-800 cm-1 and 750-400 cm-1. In between, the range 1450-800 cm-1 was the most active cluster. Each of the sample showed the different sequence of autopeak comparison. This study has examined the impact of G. lucidum on the degradation of Q. acuttisima in term of their ecosystem life chain. The components of healthy Q. acuttisima wood including lignin, cellulose, hemicellulose and calcium oxalate monohydrate underwent changes after different years of G. lucidum cultivation.
    Matched MeSH terms: Fourier Analysis
  5. Frequency analysis of capnogram signals to differentiate asthmatic and non-asthmatic conditions using radial basis function neural networks
    Kazemi M, Bala Krishnan M, Aik Howe T
    Iran J Allergy Asthma Immunol, 2013 Sep;12(3):236-46.
    PMID: 23893807
    In this paper, the method of differentiating asthmatic and non-asthmatic patients using the frequency analysis of capnogram signals is presented. Previously, manual study on capnogram signal has been conducted by several researchers. All past researches showed significant correlation between capnogram signals and asthmatic patients. However all of them are just manual study conducted through the conventional time domain method. In this study, the power spectral density (PSD) of capnogram signals is estimated by using Fast Fourier Transform (FFT) and Autoregressive (AR) modelling. The results show the non-asthmatic capnograms have one component in their PSD estimation, in contrast to asthmatic capnograms that have two components. Furthermore, there is a significant difference between the magnitude of the first component for both asthmatic and non-asthmatic capnograms. The effectiveness and performance of manipulating the characteristics of the first frequency component, mainly its magnitude and bandwidth, to differentiate between asthmatic and non-asthmatic conditions by means of receiver operating characteristic (ROC) curve analysis and radial basis function (RBF) neural network were shown. The output of this network is an integer prognostic index from 1 to 10 (depends on the severity of asthma) with an average good detection rate of 95.65% and an error rate of 4.34%. This developed algorithm is aspired to provide a fast and low-cost diagnostic system to help healthcare professional involved in respiratory care as it would be possible to monitor severity of asthma automatically and instantaneously.
    Matched MeSH terms: Fourier Analysis*
  6. Fulltext Synthesis and Characterization of the Inclusion Complex of β-cyclodextrin and Azomethine
    Sambasevam KP, Mohamad S, Sarih NM, Ismail NA
    Int J Mol Sci, 2013;14(2):3671-82.
    PMID: 23434664 DOI: 10.3390/ijms14023671
    A β-cyclodextrin (β-Cyd) inclusion complex containing azomethine as a guest was prepared by kneading method with aliquot addition of ethanol. The product was characterized by Fourier Transform Infrared (FTIR) spectrometer, 1H Nuclear Magnetic Resonance (1H NMR) and Thermogravimetric Analyzer (TGA), which proves the formation of the inclusion complex where the benzyl part of azomethine has been encapsulated by the hydrophobic cavity of β-Cyd. The interaction of β-Cyd and azomethine was also analyzed by means of spectrometry by UV-Vis spectrophotometer to determine the formation constant. The formation constant was calculated by using a modified Benesi-Hildebrand equation at 25 °C. The apparent formation constant obtained was 1.29 × 104 L/mol. Besides that, the stoichiometry ratio was also determined to be 1:1 for the inclusion complex of β-Cyd with azomethine.
    Matched MeSH terms: Fourier Analysis
  7. Fulltext Dataset of Fourier transform-infrared coupled with chemometric analysis used to distinguish accessions of Garcinia mangostana L. in Peninsular Malaysia
    Samsir SA, Bunawan H, Yen CC, Noor NM
    Data Brief, 2016 Sep;8:1-5.
    PMID: 27257614 DOI: 10.1016/j.dib.2016.04.062
    In this dataset, we distinguish 15 accessions of Garcinia mangostana from Peninsular Malaysia using Fourier transform-infrared spectroscopy coupled with chemometric analysis. We found that the position and intensity of characteristic peaks at 3600-3100 cm(-) (1) in IR spectra allowed discrimination of G. mangostana from different locations. Further principal component analysis (PCA) of all the accessions suggests the two main clusters were formed: samples from Johor, Melaka, and Negeri Sembilan (South) were clustered together in one group while samples from Perak, Kedah, Penang, Selangor, Kelantan, and Terengganu (North and East Coast) were in another clustered group.
    Matched MeSH terms: Fourier Analysis
  8. Digital Mammograms with Image Enhancement Techniques for Breast Cancer Detection: A Systematic Review
    Suradi SH, Abdullah KA
    Curr Med Imaging, 2021 Jan 26.
    PMID: 33504312 DOI: 10.2174/1573405617666210127101101
    BACKGROUND: Digital mammograms with appropriate image enhancement techniques will improve breast cancer detection, and thus increase the survival rates. The objectives of this study were to systematically review and compare various image enhancement techniques in digital mammograms for breast cancer detection.

    METHODS: A literature search was conducted with the use of three online databases namely, Web of Science, Scopus, and ScienceDirect. Developed keywords strategy was used to include only the relevant articles. A Population Intervention Comparison Outcomes (PICO) strategy was used to develop the inclusion and exclusion criteria. Image quality was analyzed quantitatively based on peak signal-noise-ratio (PSNR), Mean Squared Error (MSE), Absolute Mean Brightness Error (AMBE), Entropy, and Contrast Improvement Index (CII) values.

    RESULTS: Nine studies with four types of image enhancement techniques were included in this study. Two studies used histogram-based, three studies used frequency-based, one study used fuzzy-based and three studies used filter-based. All studies reported PSNR values whilst only four studies reported MSE, AMBE, Entropy and CII values. Filter-based was the highest PSNR values of 78.93, among other types. For MSE, AMBE, Entropy, and CII values, the highest were frequency-based (7.79), fuzzy-based (93.76), filter-based (7.92), and frequency-based (6.54) respectively.

    CONCLUSION: In summary, image quality for each image enhancement technique is varied, especially for breast cancer detection. In this study, the frequency-based of Fast Discrete Curvelet Transform (FDCT) via the UnequiSpaced Fast Fourier Transform (USFFT) shows the most superior among other image enhancement techniques.

    Matched MeSH terms: Fourier Analysis
  9. Fulltext Data on Fourier transform-infrared of Cosmos caudatus Kunth. tissues analyzed with chemometric analysis
    Gunasekaran D, Bunawan H, Ismail I, Noor NM
    Data Brief, 2018 Aug;19:1423-1427.
    PMID: 30229014 DOI: 10.1016/j.dib.2018.06.025
    In this dataset, we differentiate four different tissues of Cosmos caudatus Kunth (leaves, flowers, stem and root) obtained from UKM Bangi plot, based on Fourier transform-infrared spectroscopy. Different tissues of C. caudatus demonstrated the position and intensity of characteristic peaks at 4000-450 cm-1. Principal component analysis (PCA) shows three main groups were formed. The samples from leaves and flowers were found to be clustered together in one group, while the samples from stems and roots were clustered into two separate groups, respectively. This data provides an insight into the fingerprint identification and distribution of metabolites in the different organs of this species.
    Matched MeSH terms: Fourier Analysis
  10. Study of Structural and Luminescence Properties of Lead Lithium Borophosphate Glass System Doped with Ti Ions
    Leow T, Leong P, Eeu T, Ibrahim Z, Hussin R
    Sains Malaysiana, 2014;43:929-934.
    Study of a series of lead lithium borophosphate glass samples was performed to determine the structural and luminescence properties. The glass samples containing the composition of 20Pb0-xLi20-30B 20 3-(50-x)P 20 5-2TiO 2 (where x = 0, 5, 10, 15, 20) system were prepared using melt-quenching technique. The Pb0-Li20-B 20 3-P20 5-Ti0 2 samples were investigated for structural properties using Fourier transform infrared and photoluminescence spectroscopy for studies of luminescence properties. The results from FTIR showed the presence of trigonal and tetrahedral PO4' PO3, BO4 and B03 groups within the host network structure. The samples exhibit luminescence emission centered at 420, 482 and 496 nm when excited at 300 nm wavelength. The emission peak at 420 nm were assigned to F center emission and charge-transfer transition of Ti4+ ions. The results showed that emission intensity was dependent on lithium contents in Ti-doped lead lithium borophosphate glass composition.
    Matched MeSH terms: Fourier Analysis
  11. Effect of cellulose nanocrystals content and ph on swelling behaviour of gelatin based hydrogel
    Ooi SY, Ishak Ahmad, Mohd Cairul Iqbal Mohd Amin
    Sains Malaysiana, 2015;44:793-799.
    In this research, a novel method was performed to obtain hydrogel with superior thermal stability by incorporation
    of cellulose nanocrystals (CNC) into gelatin based hydrogel. Glutaraldehyde was used as cross-linker due to its high
    chemical reactivity towards NH2
    group on gelatin. Different ratio of gelatin/CNC hydrogel was produced in order to study
    the effects of CNC towards the swelling behaviour and thermal stability of gelatin based hydrogel. The obtained hydrogel
    was subjected to Fourier transform infrared (FTIR) to verify that gelatin had been cross-linked, swelling test with different
    pH for swelling behaviour and thermogravimetric analysis (TGA) for thermal stability. The presence of C=N stretching
    group in the FTIR spectrum for gelatin/CNC hydrogel indicated that the cross-linking reaction between gelatin monomer
    had been successfully carried out. The hydrogel showed impressive pH sensitivity and maximum swelling was obtained
    at pH3. The TGA results clearly showed that the incorporation of CNC into gelatin was able to produce hydrogel with
    higher thermal stability compare to neat gelatin.
    Matched MeSH terms: Fourier Analysis
  12. Synthesis and structural characterization of 6-(N-Methyl-pyridin-2-ylcarbamoyl)-pyridine-2-carboxylic Acid Methyl Ester Isomers
    Maisara Abdul Kadir, Nafisah Mansor, Uwaisulqarni M. Osman
    Sains Malaysiana, 2017;46:725-731.
    A series of monoamide isomers have been successfully synthesised and characterised using combination of common spectroscopic techniques such Fourier Transform Infrared (FT-IR), 1H and 13C Nuclear Magnetic Resonance (NMR) and Ultraviolet-visible (UV-vis). The monoamide compounds namely 6-(3-methyl-pyridin-2-ylcarbamoyl)-pyridine2-carboxylic acid methyl ester (L1), 6-(4-methyl-pyridin-2-ylcarbamoyl)-pyridine-2-carboxylic acid methyl ester (L2), 6-(5-methyl-pyridin-2-ylcarbamoyl)-pyridine-2-carboxylic acid methyl ester (L3) and 6-(6-methyl-pyridin-2ylcarbamoyl)-pyridine-2-carboxylic acid methyl ester (L4) were prepared from reaction between 6-(methoxycarbonyl) pyridine-2-carboxylic acid with 2-amino-N-methylpyridine (where N = 3, 4, 5 and 6) by using acyl chloride reaction. In this present studies, the synthesis and characterization of these compounds are discussed along with the inductive effects contributed by methyl substituted groups at the pyridine ring.
    Matched MeSH terms: Fourier Analysis
  13. Fulltext The potential of incorporation of binary salts and ionic liquid in P(VP-co-VAc) gel polymer electrolyte in electrochemical and photovoltaic performances
    Ming NH, Ramesh S, Ramesh K
    Sci Rep, 2016 06 08;6:27630.
    PMID: 27273020 DOI: 10.1038/srep27630
    In this study, dye-sensitized solar cells (DSSCs) has been assembled with poly(1-vinylpyrrolidone-co-vinyl acetate) (P(VP-co-VAc)) gel polymer electrolytes (GPEs) which have been incorporated with binary salt and an ionic liquid. The potential of this combination was studied and reported. The binary salt system GPEs was having ionic conductivity and power conversion efficiency (PCE) that could reach up to 1.90 × 10(-3) S cm(-1) and 5.53%, respectively. Interestingly, upon the addition of the ionic liquid, MPII into the binary salt system the ionic conductivity and PCE had risen steadily up to 4.09 × 10(-3) S cm(-1) and 5.94%, respectively. In order to know more about this phenomenon, the electrochemical impedance studies (EIS) of the GPE samples have been done and reported. Fourier transform infrared studies (FTIR) and thermogravimetric analysis (TGA) have also been studied to understand more on the structural and thermal properties of the GPEs. The Nyquist plot and Bodes plot studies have been done in order to understand the electrochemical properties of the GPE based DSSCs and Tafel polarization studies were done to determine the electrocatalytic activity of the GPE samples.
    Matched MeSH terms: Fourier Analysis
  14. Fulltext Biosorption Potential of Bacillus salmalaya Strain 139SI for Removal of Cr(VI) from Aqueous Solution
    Dadrasnia A, Chuan Wei KS, Shahsavari N, Azirun MS, Ismail S
    Int J Environ Res Public Health, 2015 Dec;12(12):15321-38.
    PMID: 26633454 DOI: 10.3390/ijerph121214985
    The present study investigated the biosorption capacity of live and dead cells of a novel Bacillus strain for chromium. The optimum biosorption condition was evaluated in various analytical parameters, including initial concentration of chromium, pH, and contact time. The Langmuir isotherm model showed an enhanced fit to the equilibrium data. Live and dead biomasses followed the monolayer biosorption of the active surface sites. The maximum biosorption capacity was 20.35 mg/g at 25 °C, with pH 3 and contact time of 50 min. Strain 139SI was an excellent host to the hexavalent chromium. The biosorption kinetics of chromium in the dead and live cells of Bacillus salmalaya (B. salmalaya) 139SI followed the pseudo second-order mechanism. Scanning electron microscopy and fourier transform infrared indicated significant influence of the dead cells on the biosorption of chromium based on cell morphological changes. Approximately 92% and 70% desorption efficiencies were achieved using dead and live cells, respectively. These findings demonstrated the high sorption capacity of dead biomasses of B. salmalaya 139SI in the biosorption process. Thermodynamic evaluation (ΔG⁰, ΔH⁰, and ΔS⁰) indicated that the mechanism of Cr(VI) adsorption is endothermic; that is, chemisorption. Results indicated that chromium accumulation occurred in the cell wall of B. salmalaya 139SI rather than intracellular accumulation.
    Matched MeSH terms: Fourier Analysis
  15. Binary particle swarm optimization for feature selection in detection of infants with hypothyroidism
    Zabidi A, Khuan LY, Mansor W, Yassin IM, Sahak R
    Annu Int Conf IEEE Eng Med Biol Soc, 2011;2011:2772-5.
    PMID: 22254916 DOI: 10.1109/IEMBS.2011.6090759
    Hypothyroidism in infants is caused by the insufficient production of hormones by the thyroid gland. Due to stress in the chest cavity as a result of the enlarged liver, their cry signals are unique and can be distinguished from the healthy infant cries. This study investigates the effect of feature selection with Binary Particle Swarm Optimization on the performance of MultiLayer Perceptron classifier in discriminating between the healthy infants and infants with hypothyroidism from their cry signals. The feature extraction process was performed on the Mel Frequency Cepstral coefficients. Performance of the MLP classifier was examined by varying the number of coefficients. It was found that the BPSO enhances the classification accuracy while reducing the computation load of the MLP classifier. The highest classification accuracy of 99.65% was achieved for the MLP classifier, with 36 filter banks, 5 hidden nodes and 11 BPS optimised MFC coefficients.
    Matched MeSH terms: Fourier Analysis
  16. Fulltext Fully-automated identification of fish species based on otolith contour: using short-time Fourier transform and discriminant analysis (STFT-DA)
    Salimi N, Loh KH, Kaur Dhillon S, Chong VC
    PeerJ, 2016;4:e1664.
    PMID: 26925315 DOI: 10.7717/peerj.1664
    Background. Fish species may be identified based on their unique otolith shape or contour. Several pattern recognition methods have been proposed to classify fish species through morphological features of the otolith contours. However, there has been no fully-automated species identification model with the accuracy higher than 80%. The purpose of the current study is to develop a fully-automated model, based on the otolith contours, to identify the fish species with the high classification accuracy. Methods. Images of the right sagittal otoliths of 14 fish species from three families namely Sciaenidae, Ariidae, and Engraulidae were used to develop the proposed identification model. Short-time Fourier transform (STFT) was used, for the first time in the area of otolith shape analysis, to extract important features of the otolith contours. Discriminant Analysis (DA), as a classification technique, was used to train and test the model based on the extracted features. Results. Performance of the model was demonstrated using species from three families separately, as well as all species combined. Overall classification accuracy of the model was greater than 90% for all cases. In addition, effects of STFT variables on the performance of the identification model were explored in this study. Conclusions. Short-time Fourier transform could determine important features of the otolith outlines. The fully-automated model proposed in this study (STFT-DA) could predict species of an unknown specimen with acceptable identification accuracy. The model codes can be accessed at http://mybiodiversityontologies.um.edu.my/Otolith/ and https://peerj.com/preprints/1517/. The current model has flexibility to be used for more species and families in future studies.
    Matched MeSH terms: Fourier Analysis
  17. Fulltext Natural Inspired Carboxymethyl Cellulose (CMC) Doped with Ammonium Carbonate (AC) as Biopolymer Electrolyte
    Sohaimy MIHA, Isa MINM
    Polymers (Basel), 2020 Oct 26;12(11).
    PMID: 33114745 DOI: 10.3390/polym12112487
    Green and safer materials in energy storage technology are important right now due to increased consumption. In this study, a biopolymer electrolyte inspired from natural materials was developed by using carboxymethyl cellulose (CMC) as the core material and doped with varied ammonium carbonate (AC) composition. X-ray diffraction (XRD) shows the prepared CMC-AC electrolyte films exhibited low crystallinity content, Xc (~30%) for sample AC7. A specific wavenumber range between 900-1200 cm-1 and 1500-1800 cm-1 was emphasized in Fourier transform infrared (FTIR) testing, as this is the most probable interaction to occur. The highest ionic conductivity, σ of the electrolyte system achieved was 7.71 × 10-6 Scm-1 and appeared greatly dependent on ionic mobility, µ and diffusion coefficient, D. The number of mobile ions, η, increased up to the highest conducting sample (AC7) but it became less prominent at higher AC composition. The transference measurement, tion showed that the electrolyte system was predominantly ionic with sample AC7 having the highest value (tion = 0.98). Further assessment also proved that the H+ ion was the main conducting species in the CMC-AC electrolyte system, which presumably was due to protonation of ammonium salt onto the complexes site and contributed to the overall ionic conductivity enhancement.
    Matched MeSH terms: Fourier Analysis
  18. Fulltext Functionalized KIT-6/Polysulfone Mixed Matrix Membranes for Enhanced CO2/CH4 Gas Separation
    Chew TL, Ding SH, Oh PC, Ahmad AL, Ho CD
    Polymers (Basel), 2020 Oct 09;12(10).
    PMID: 33050226 DOI: 10.3390/polym12102312
    The development of mixed matrix membranes (MMMs) for effective gas separation has been gaining popularity in recent years. The current study aimed at the fabrication of MMMs incorporated with various loadings (0-4 wt%) of functionalized KIT-6 (NH2KIT-6) [KIT: Korea Advanced Institute of Science and Technology] for enhanced gas permeation and separation performance. NH2KIT-6 was characterized by field emission scanning electron microscope (FESEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR), and N2 adsorption-desorption analysis. The fabricated membranes were subjected to FESEM and FTIR analyses. The effect of NH2KIT-6 loading on the CO2 permeability and ideal CO2/CH4 selectivity of the fabricated membranes were investigated in gas permeation and separation studies. The successfulness of (3-Aminopropyl) triethoxysilane (APTES) functionalization on KIT-6 was confirmed by FTIR analysis. As observed from FESEM images, MMMs with no voids in the matrix were successfully fabricated at a low NH2KIT-6 loading of 0 to 2 wt%. The CO2 permeability and ideal CO2/CH4 selectivity increased when NH2KIT-6 loading was increased from 0 to 2 wt%. However, a further increase in NH2KIT-6 loading beyond 2 wt% led to a drop in ideal CO2/CH4 selectivity. In the current study, a significant increase of about 47% in ideal CO2/CH4 selectivity was achieved by incorporating optimum 2 wt% NH2KIT-6 into the MMMs.
    Matched MeSH terms: Fourier Analysis
  19. Fulltext Predicting the degradation potential of Acid blue 113 by different oxidants using quantum chemical analysis
    Asghar A, Bello MM, Raman AAA, Daud WMAW, Ramalingam A, Zain SBM
    Heliyon, 2019 Sep;5(9):e02396.
    PMID: 31517121 DOI: 10.1016/j.heliyon.2019.e02396
    In this work, quantum chemical analysis was used to predict the degradation potential of a recalcitrant dye, Acid blue 113, by hydrogen peroxide, ozone, hydroxyl radical and sulfate radical. Geometry optimization and frequency calculations were performed at 'Hartree Fock', 'Becke, 3-parameter, Lee-Yang-Parr' and 'Modified Perdew-Wang exchange combined with PW91 correlation' levels of study using 6-31G* and 6-31G** basis sets. The Fourier Transform-Raman spectra of Acid blue 113 were recorded and a complete analysis on vibrational assignment and fundamental modes of model compound was performed. Natural bond orbital analysis revealed that Acid blue 113 has a highly stable structure due to strong intermolecular and intra-molecular interactions. Mulliken charge distribution and molecular electrostatic potential map of the dye also showed a strong influence of functional groups on the neighboring atoms. Subsequently, the reactivity of the dye towards the oxidants was compared based on the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy values. The results showed that Acid blue 113 with a HOMO value -5.227 eV exhibits a nucleophilic characteristic, with a high propensity to be degraded by ozone and hydroxyl radical due to their lower HOMO-LUMO energy gaps of 4.99 and 4.22 eV respectively. On the other hand, sulfate radical and hydrogen peroxide exhibit higher HOMO-LUMO energy gaps of 7.92 eV and 8.10 eV respectively, indicating their lower reactivity towards Acid blue 113. We conclude that oxidation processes based on hydroxyl radical and ozone would offer a more viable option for the degradation of Acid blue 113. This study shows that quantum chemical analysis can assist in selecting appropriate advanced oxidation processes for the treatment of textile effluent.
    Matched MeSH terms: Fourier Analysis
  20. The use of Fourier transform mid infrared (FT-MIR) spectroscopy for detection and quantification of adulteration in virgin coconut oil
    Rohman A, Che Man YB
    Food Chem, 2011 Nov 15;129(2):583-588.
    PMID: 30634271 DOI: 10.1016/j.foodchem.2011.04.070
    Currently, the authentication of virgin coconut oil (VCO) has become very important due to the possible adulteration of VCO with cheaper plant oils such as corn (CO) and sunflower (SFO) oils. Methods involving Fourier transform mid infrared (FT-MIR) spectroscopy combined with chemometrics techniques (partial least square (PLS) and discriminant analysis (DA)) were developed for quantification and classification of CO and SFO in VCO. MIR spectra of oil samples were recorded at frequency regions of 4000-650cm-1 on horizontal attenuated total reflectance (HATR) attachment of FTIR. DA can successfully classify VCO and that adulterated with CO and SFO using 10 principal components. Furthermore, PLS model correlates the actual and FTIR estimated values of oil adulterants (CO and SFO) with coefficient of determination (R2) of 0.999.
    Matched MeSH terms: Fourier Analysis
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