Displaying publications 41 - 60 of 147 in total

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  1. Fulltext An improved wrapper-based feature selection method for machinery fault diagnosis
    Hui KH, Ooi CS, Lim MH, Leong MS, Al-Obaidi SM
    PLoS One, 2017;12(12):e0189143.
    PMID: 29261689 DOI: 10.1371/journal.pone.0189143
    A major issue of machinery fault diagnosis using vibration signals is that it is over-reliant on personnel knowledge and experience in interpreting the signal. Thus, machine learning has been adapted for machinery fault diagnosis. The quantity and quality of the input features, however, influence the fault classification performance. Feature selection plays a vital role in selecting the most representative feature subset for the machine learning algorithm. In contrast, the trade-off relationship between capability when selecting the best feature subset and computational effort is inevitable in the wrapper-based feature selection (WFS) method. This paper proposes an improved WFS technique before integration with a support vector machine (SVM) model classifier as a complete fault diagnosis system for a rolling element bearing case study. The bearing vibration dataset made available by the Case Western Reserve University Bearing Data Centre was executed using the proposed WFS and its performance has been analysed and discussed. The results reveal that the proposed WFS secures the best feature subset with a lower computational effort by eliminating the redundancy of re-evaluation. The proposed WFS has therefore been found to be capable and efficient to carry out feature selection tasks.
    Matched MeSH terms: Vibration
  2. Fulltext Search for Resonant Production of High-Mass Photon Pairs in Proton-Proton Collisions at sqrt[s]=8 and 13 TeV
    Khachatryan V, Sirunyan AM, Tumasyan A, Adam W, Asilar E, Bergauer T, et al.
    Phys Rev Lett, 2016 Jul 29;117(5):051802.
    PMID: 27517765 DOI: 10.1103/PhysRevLett.117.051802
    A search for the resonant production of high-mass photon pairs is presented. The analysis is based on samples of proton-proton collision data collected by the CMS experiment at center-of-mass energies of 8 and 13 TeV, corresponding to integrated luminosities of 19.7 and 3.3  fb^{-1}, respectively. The interpretation of the search results focuses on spin-0 and spin-2 resonances with masses between 0.5 and 4 TeV and with widths, relative to the mass, between 1.4×10^{-4} and 5.6×10^{-2}. Limits are set on scalar resonances produced through gluon-gluon fusion, and on Randall-Sundrum gravitons. A modest excess of events compatible with a narrow resonance with a mass of about 750 GeV is observed. The local significance of the excess is approximately 3.4 standard deviations. The significance is reduced to 1.6 standard deviations once the effect of searching under multiple signal hypotheses is considered. More data are required to determine the origin of this excess.
    Matched MeSH terms: Vibration
  3. Fulltext Tapered Polymer Fiber Sensors for Reinforced Concrete Beam Vibration Detection
    Luo D, Ibrahim Z, Ma J, Ismail Z, Iseley DT
    Sensors (Basel), 2016 Dec 16;16(12).
    PMID: 27999245 DOI: 10.3390/s16122149
    In this study, tapered polymer fiber sensors (TPFSs) have been employed to detect the vibration of a reinforced concrete beam (RC beam). The sensing principle was based on transmission modes theory. The natural frequency of an RC beam was theoretically analyzed. Experiments were carried out with sensors mounted on the surface or embedded in the RC beam. Vibration detection results agreed well with Kistler accelerometers. The experimental results found that both the accelerometer and TPFS detected the natural frequency function of a vibrated RC beam well. The mode shapes of the RC beam were also found by using the TPFSs. The proposed vibration detection method provides a cost-comparable solution for a structural health monitoring (SHM) system in civil engineering.
    Matched MeSH terms: Vibration
  4. Fulltext Reliability of a Malay-translated questionnaire for use in a hand-arm vibration syndrome study in Malaysia
    Su TA, Hoe VC
    Singapore Med J, 2008 Dec;49(12):1038-45.
    PMID: 19122959
    Validity and reliability of the information relating to hand-transmitted vibration exposure and vibration-related health outcome are very important for case finding in hand-arm vibration syndrome (HAVS) studies. In a local HAVS study among a group of construction workers in Kuala Lumpur, Malaysia, a questionnaire translated into Malay was created based on the Hand-transmitted Vibration Health Surveillance--Initial Questionnaire and Clinical Assessment, from Vibration Injury Network. This study was conducted to determine the reliability of standardised questions in the questionnaire used in the study.
    Matched MeSH terms: Vibration/adverse effects; Hand-Arm Vibration Syndrome/diagnosis*
  5. Fulltext Investigation of inerter-based suspension systems for heavy vehicles
    Soong MF, Ramli R, Saifizul AA, Goh KY, Long SX
    PLoS One, 2023;18(1):e0280290.
    PMID: 36662679 DOI: 10.1371/journal.pone.0280290
    The inerter is a two-terminal component that can be added to the spring-and-damper configuration of a suspension system. It has the property that the force exerted is proportional to the relative acceleration at its terminals. Studies have demonstrated the inerter's benefit of providing superior vibration isolation when it is used in the vehicle suspension of passenger cars. However, similar benefit on another common vehicle class on the roads, namely heavy vehicles, remain to be shown, as these vehicles have vastly different parameter values than passenger cars. This study is an investigation on the performance improvement brought by an inerter in the suspension of common heavy vehicles. In the study, the parameter values of a truck and a bus were adopted in the quarter vehicle model with two different spring-damper-inerter configurations (parallel and serial inerter), and the improvements in vibration isolation and road holding capability were determined by optimization of inertance. Results show that the inerter is similarly effective in providing the said improvements when implemented on heavy vehicles instead of on passenger cars, judging from reductions in sprung mass acceleration and dynamic tire load. It is also observed that the performance benefit is associated with larger optimum inertance than that for passenger cars. Overall, the inerter has been shown to be beneficial in the parallel and serial configurations, both of which are common and can be practically implemented in the suspension of heavy vehicles.
    Matched MeSH terms: Vibration
  6. Hand-arm vibration syndrome among a group of construction workers in Malaysia
    Su TA, Hoe VC, Masilamani R, Awang Mahmud AB
    Occup Environ Med, 2011 Jan;68(1):58-63.
    PMID: 20935287 DOI: 10.1136/oem.2009.052373
    To determine the extent of hand transmitted vibration exposure problems, particularly hand-arm vibration syndrome (HAVS), among construction workers in Malaysia.
    Matched MeSH terms: Vibration/adverse effects; Hand-Arm Vibration Syndrome/etiology; Hand-Arm Vibration Syndrome/epidemiology*
  7. Fulltext Characterisation of structure-borne sound source using reception plate method
    Putra A, Saari NF, Bakri H, Ramlan R, Dan RM
    ScientificWorldJournal, 2013;2013:742853.
    PMID: 24324380 DOI: 10.1155/2013/742853
    A laboratory-based experiment procedure of reception plate method for structure-borne sound source characterisation is reported in this paper. The method uses the assumption that the input power from the source installed on the plate is equal to the power dissipated by the plate. In this experiment, rectangular plates having high and low mobility relative to that of the source were used as the reception plates and a small electric fan motor was acting as the structure-borne source. The data representing the source characteristics, namely, the free velocity and the source mobility, were obtained and compared with those from direct measurement. Assumptions and constraints employing this method are discussed.
    Matched MeSH terms: Vibration*
  8. Fulltext The prevalence of hand arm vibration syndrome among automobile assembly workers
    Shamsul Bahri Mohd Tamrin, Nor MaizuraYusoff, Anita Abd Rahman, Dayana Hazwani, M.S.N., Mansour A. Balkhyour
    Malaysian Journal of Public Health Medicine, 2016;16(20):128-136.
    MyJurnal
    The objectives of this study are to determine the prevalence of hand-arm vibration (HAVS) among the automobile
    assembly workers and the associated risks. A cross sectional study was conducted to determine the prevalence of
    HAVS and also ascertain the association between HAVS and reduction in VPT among workers using vibration hand held
    tool in automobile industry. Aim of this study was to determine the prevalence Hand Arm Vibration Syndrome
    (HAVS) among vibrating hand held tool exposed workers. A cross sectional study design using structured
    questionnaire and invasive measurement of vibrotactile perception threshold (VPT) at the fingertips was conducted
    in one of the automobile company in Klang Valley. All the respondents were hand arm vibration exposed workers. A
    total 109 assembly line workers with at least one year job tenure participated in this study. The finding revealed
    that 27.5% of workers reported HAVS through questionnaire. This study consisted of 109 respondents. All of them
    were male. The mean age was 32.9 years. The mean daily vibration exposure for 8-hours was 1.41m/s2. There was
    11% of the tools measured were above the Action Level recommended by European Union Directive 2002. The overall
    prevalence of HAVS based on reported symptom through questionnaire was 27.5%. None of the respondent reported
    any whiteness at their fingers due to exposure to vibration. However, 36.7% of the respondent reported tingling
    sensation and 57.8 % reported the feeling of numbness in their hands. Only 10.1% claim that the pain was
    persistence. Since this study was done among exposed workers without control group, the thresholds were measured
    by comparing the observed VPT with the VPT of healthy population provided by ISO 13091-2. The result showed that
    98.2% of the respondent in this study having positive threshold which indicate the percentage of respondent that
    having deterioration in finger tactile perception. The positive threshold from comparison above showed that the
    respondent of this study was affected with the vibration exposure. The value proven that the exposure has caused
    the deterioration of tactile sensitivity in 98.2% of respondent in this study which showed by having positive threshold
    compared to healthy population. The result also showed that there was a significant correlation between daily
    vibration exposure A (8) and VPT at both frequency tested which was 31.5Hz (r = 0.417, p = 0.002) and 125Hz (r =
    0.480, p = 0.001). Even though the mean daily vibration exposure for 8-hours was low and below the recommended
    level, the workers still exposed to the effect of hand arm vibration.
    Matched MeSH terms: Vibration; Hand-Arm Vibration Syndrome
  9. New mechanical disruption method for extraction of whole cell protein from Candida albicans
    Wong SF, Mak JW, Pook PC
    Southeast Asian J Trop Med Public Health, 2007 May;38(3):512-8.
    PMID: 17877228
    Cell disruption or lysis is a crucial step to obtain cellular components for various biological studies. We subjected different concentrations of Candida albicans to 5, 10, 15 and 20 cycles of disruption. The degree of cell lysis was observed using light microscopy and the yields obtained were measured and analysed. The optimum extraction with 1 x 10(10) yeast cells/ml was achieved after 5 cycles of disruption with 1.0 mm diameter glass beads at 5,000 rpm. Approximately 80% of the cells were lysed and the protein yield was 6,000 microg/ml. SDS-PAGE analysis revealed approximately 25 distinct protein bands with molecular weights ranging from 8 kDa to 220 kDa. We conclude that this mechanical disruption of fungal cells is a rapid, efficient and inexpensive technique for extracting whole cell proteins from yeast cells.
    Matched MeSH terms: Vibration*
  10. A comparison of hand-arm vibration syndrome between Malaysian and Japanese workers
    Su AT, Fukumoto J, Darus A, Hoe VC, Miyai N, Isahak M, et al.
    J Occup Health, 2013;55(6):468-78.
    PMID: 24162147
    OBJECTIVES: The aim of this study was to investigate the clinical characteristics of HAVS in a tropical environment in comparison with a temperate environment.

    METHODS: We conducted a series medical examinations among the forestry, construction and automobile industry workers in Malaysia adopting the compulsory medical examination procedure used by Wakayama Medical University for Japanese vibratory tools workers. We matched the duration of vibration exposure and compared our results against the Japanese workers. We also compared the results of the Malaysian tree fellers against a group of symptomatic Japanese tree fellers diagnosed with HAVS.

    RESULTS: Malaysian subjects reported a similar prevalence of finger tingling, numbness and dullness (Malaysian=25.0%, Japanese=21.5%, p=0.444) but had a lower finger skin temperature (FST) and higher vibrotactile perception threshold (VPT) values as compared with the Japanese workers. No white finger was reported in Malaysian subjects. The FST and VPT of the Malaysian tree fellers were at least as bad as the Japanese tree fellers despite a shorter duration (mean difference=20.12 years, 95%CI=14.50, 25.40) of vibration exposure.

    CONCLUSIONS: Although the vascular disorder does not manifest clinically in the tropical environment, the severity of HAVS can be as bad as in the temperate environment with predominantly neurological disorder. Hence, it is essential to formulate national legislation for the control of the occupational vibration exposure.

    Matched MeSH terms: Vibration/adverse effects; Hand-Arm Vibration Syndrome/epidemiology*
  11. Fulltext An Improved Method of Parameter Identification and Damage Detection in Beam Structures under Flexural Vibration Using Wavelet Multi-Resolution Analysis
    Ravanfar SA, Razak HA, Ismail Z, Monajemi H
    Sensors (Basel), 2015;15(9):22750-75.
    PMID: 26371005 DOI: 10.3390/s150922750
    This paper reports on a two-step approach for optimally determining the location and severity of damage in beam structures under flexural vibration. The first step focuses on damage location detection. This is done by defining the damage index called relative wavelet packet entropy (RWPE). The damage severities of the model in terms of loss of stiffness are assessed in the second step using the inverse solution of equations of motion of a structural system in the wavelet domain. For this purpose, the connection coefficient of the scaling function to convert the equations of motion in the time domain into the wavelet domain is applied. Subsequently, the dominant components based on the relative energies of the wavelet packet transform (WPT) components of the acceleration responses are defined. To obtain the best estimation of the stiffness parameters of the model, the least squares error minimization is used iteratively over the dominant components. Then, the severity of the damage is evaluated by comparing the stiffness parameters of the identified model before and after the occurrence of damage. The numerical and experimental results demonstrate that the proposed method is robust and effective for the determination of damage location and accurate estimation of the loss in stiffness due to damage.
    Matched MeSH terms: Vibration
  12. Evaluation of 2-indolcarbohydrazones as potent α-glucosidase inhibitors, in silico studies and DFT based stereochemical predictions
    Taha M, Ismail NH, Javaid K, Imran S, Anouar el H, Wadood A, et al.
    Bioorg Chem, 2015 Dec;63:24-35.
    PMID: 26398141 DOI: 10.1016/j.bioorg.2015.09.001
    2-Indolcarbohydrazones 1-28 were synthesized and evaluated for their α-glucosidase inhibitory potential. A varying degree of inhibitory potential with IC50 values in the range of 2.3±0.11-226.4±6.8μM was observed while comparing these outcomes with the standard acarbose (IC50=906.0±6.3μM). The stereochemistry of ten (10) randomly selected compounds (1, 3, 6, 8, 12, 18, 19, 23, 25 and 28) was predicted by Density Functional Theory (DFT). The stability of E isomer was deduced by comparing the calculated and experimental vibration modes of νCO, νNC and νCH (CH in NCH-R). It was observed that except compound 18, all other compounds were deduced to have E configuration while molecular modeling studies revealed the key interactions between enzyme and synthesized compounds.
    Matched MeSH terms: Vibration
  13. (2E)-1-(5-Chlorothiophen-2-yl)-3-{4-[(E)-2-phenylethenyl]phenyl}prop-2-en-1-one: Synthesis, XRD, FT-IR, Raman and DFT studies
    Parlak C, Ramasami P, Kumar CS, Tursun M, Quah CK, Rhyman L, et al.
    Spectrochim Acta A Mol Biomol Spectrosc, 2015 Oct 5;149:385-95.
    PMID: 25974671 DOI: 10.1016/j.saa.2015.04.022
    A novel (2E)-1-(5-chlorothiophen-2-yl)-3-{4-[(E)-2-phenylethenyl]phenyl}prop-2-en-1-one [C21H15ClOS] compound has been synthesized and its structure has been characterized by FT-IR, Raman and single-crystal X-ray diffraction techniques. The conformational isomers, optimized geometric parameters, normal mode frequencies and corresponding vibrational assignments of the compound have been examined by means of HF, MP2, BP86, BLYP, BMK, B3LYP, B3PW91, B3P86 and M06-2X functionals. Reliable vibrational assignments and molecular orbitals have been investigated by the potential energy distribution and natural bonding orbital analyses, respectively. The compound crystallizes in the triclinic space group P-1 with the cis-trans-trans form. There is a good agreement between the experimentally determined structural parameters and vibrational frequencies of the compound and those predicted theoretically using the density functional theory with the BLYP and BP86 functionals.
    Matched MeSH terms: Vibration
  14. Fulltext New regression model for predicting hand-arm vibration (HAV) of Malaysian Army (MA) three-tonne truck steering wheels
    Aziz SA, Nuawi MZ, Nor MJ
    J Occup Health, 2015;57(6):513-20.
    PMID: 26269278 DOI: 10.1539/joh.14-0206-OA
    OBJECTIVE: The objective of this study was to present a new method for determination of hand-arm vibration (HAV) in Malaysian Army (MA) three-tonne truck steering wheels based on changes in vehicle speed using regression model and the statistical analysis method known as Integrated Kurtosis-Based Algorithm for Z-Notch Filter Technique Vibro (I-kaz Vibro).

    METHODOLOGY: The test was conducted for two different road conditions, tarmac and dirt roads. HAV exposure was measured using a Brüel & Kjær Type 3649 vibration analyzer, which is capable of recording HAV exposures from steering wheels. The data was analyzed using I-kaz Vibro to determine the HAV values in relation to varying speeds of a truck and to determine the degree of data scattering for HAV data signals.

    RESULTS: Based on the results obtained, HAV experienced by drivers can be determined using the daily vibration exposure A(8), I-kaz Vibro coefficient (Ƶ(v)(∞)), and the I-kaz Vibro display. The I-kaz Vibro displays also showed greater scatterings, indicating that the values of Ƶ(v)(∞) and A(8) were increasing. Prediction of HAV exposure was done using the developed regression model and graphical representations of Ƶ(v)(∞). The results of the regression model showed that Ƶ(v)(∞) increased when the vehicle speed and HAV exposure increased.

    DISCUSSION: For model validation, predicted and measured noise exposures were compared, and high coefficient of correlation (R(2)) values were obtained, indicating that good agreement was obtained between them. By using the developed regression model, we can easily predict HAV exposure from steering wheels for HAV exposure monitoring.

    Matched MeSH terms: Vibration*; Hand-Arm Vibration Syndrome/etiology
  15. Absolute Photoabsorption Cross-Sections of Methanol for Terrestrial and Astrophysical Relevance
    Lange E, Lozano AI, Jones NC, Hoffmann SV, Kumar S, Śmiałek MA, et al.
    J Phys Chem A, 2020 Sep 30.
    PMID: 32941031 DOI: 10.1021/acs.jpca.0c06615
    We investigate the methanol absorption spectrum in the range 5.5-10.8 eV to provide accurate and absolute cross-sections values. The main goal of this study is to provide a comprehensive analysis of methanol electronic-state spectroscopy by employing high-resolution vacuum ultraviolet (VUV) photoabsorption measurements together with state-of-the-art quantum chemical calculation methods. The VUV spectrum reveals several new features that are not previously reported in literature, for n > 3 in the transitions (nsσ(a') ← (2a″)) (1A' ← X̃1A') and (nsσ, npσ, npσ', ndσ ← (7a')) (1A' ← X̃1A'), and with particular relevance to vibrational progressions of the CH3 rocking mode, v11'(a″), mode in the (3pπ(a″) ← (2a″)) (21A' ← X̃1A') absorption band at 8.318 eV. The measured absolute photoabsorption cross-sections have subsequently been used to calculate the photolysis lifetime of methanol in the Earth's atmosphere from the ground level up to the limit of the stratosphere (50 km altitude). This shows that solar photolysis plays a negligible role in the removal of methanol from the lower atmosphere compared with competing sink mechanisms. Torsional potential energy scans, as a function of the internal rotation angle for the ground and first Rydberg states, have also been calculated as part of this investigation.
    Matched MeSH terms: Vibration
  16. Lamb to Rayleigh Wave Conversion on Superstrates as a Means to Facilitate Disposable Acoustomicrofluidic Applications
    Wong KS, Lee L, Hung YM, Yeo LY, Tan MK
    Anal Chem, 2019 10 01;91(19):12358-12368.
    PMID: 31500406 DOI: 10.1021/acs.analchem.9b02850
    Rayleigh surface acoustic waves (SAWs) have been demonstrated as a powerful and effective means for driving a wide range of microfluidic actuation processes. Traditionally, SAWs have been generated on piezoelectric substrates, although the cost of the material and the electrode deposition process makes them less amenable as low-cost and disposable components. As such, a "razor-and-blades" model that couples the acoustic energy of the SAW on the piezoelectric substrate through a fluid coupling layer and into a low-cost and, hence, disposable silicon superstrate on which various microfluidic processes can be conducted has been proposed. Nevertheless, it was shown that only bulk vibration in the form of Lamb waves can be excited in the superstrate, which is considerably less efficient and flexible in terms of microfluidic functionality compared to its surface counterpart, that is, the SAW. Here, we reveal an extremely simple way that quite unexpectedly and rather nonintuitively allows SAWs to be generated on the superstrate-by coating the superstrate with a thin gold layer. In addition to verifying the existence of the SAW on the coated superstrate, we carry out finite-difference time domain numerical simulations that not only confirm the experimental observations but also facilitate an understanding of the surprising difference that the coating makes. Finally, we elucidate the various power-dependent particle concentration phenomena that can be carried out in a sessile droplet atop the superstrate and show the possibility for simply carrying out rapid and effective microcentrifugation-a process that is considerably more difficult with Lamb wave excitation on the superstrate.
    Matched MeSH terms: Vibration
  17. Fulltext System identification of helical strakes suppressed vortexinduced vibration for flexible pipes
    Ooi, Ching Sheng, Lim, Meng Hee, Lee, Kee Quen, Kang, Hooi Siang, Mohd Salman Leong
    Pertanika Journal of Science & Technology, 2020;28(2):493-508.
    MyJurnal
    Previous studies have indicated that the pipe-surface-mounted helical strakes effectively reduce vortex-induced vibration (VIV) under a uniform flow application, particularly during the lock-in region. Since VIV experiments are time-consuming, observation is generated with an interval helical strakes parameter in pitch and height to lessen tedious procedures and repetitive post-processing analyses. The aforementioned result subset is insufficient for helical strakes design optimisation because the trade-off between the helical strakes dimension, lock-in region and flow velocity are non-trivial. Thus, a parametric model based on an improved recursive least squares (RLS) parameter estimation technique is proposed to define the statistical relationship between input, or strakes and pipe dimension, and output, or VIV amplitude ratio. As results suggested, revised RLS estimated VIV model demonstrated an optimal prediction with the highest coefficient of determination and lowest Integral Absolute Error. The feasibility of VIV parametric model was validated by embed into Genetic Algorithm (GA) as the fitness function to acquire a desirable helical strakes dimension with minimum VIV amplitude. The rapid generation of optimal helical strakes dimension which returned the highest VIV suppression implied a superior simulation method compared to the experimental outcome.
    Matched MeSH terms: Vibration
  18. Search for Narrow Hγ Resonances in Proton-Proton Collisions at sqrt[s]=13  TeV
    Sirunyan AM, Tumasyan A, Adam W, Ambrogi F, Asilar E, Bergauer T, et al.
    Phys Rev Lett, 2019 Mar 01;122(8):081804.
    PMID: 30932612 DOI: 10.1103/PhysRevLett.122.081804
    A search for heavy, narrow resonances decaying to a Higgs boson and a photon (Hγ) has been performed in proton-proton collision data at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 35.9  fb^{-1} collected with the CMS detector at the LHC in 2016. Events containing a photon and a Lorentz-boosted hadronically decaying Higgs boson reconstructed as a single, large-radius jet are considered, and the γ+jet invariant mass spectrum is analyzed for the presence of narrow resonances. To increase the sensitivity of the search, events are categorized depending on whether or not the large-radius jet can be identified as a result of the merging of two jets originating from b quarks. Results in both categories are found to agree with the predictions of the standard model. Upper limits on the production rate of Hγ resonances are set as a function of their mass in the range of 720-3250 GeV, representing the most stringent constraints to date.
    Matched MeSH terms: Vibration
  19. Spectroscopic studies for the inclusion complexation of ketoprofen enantiomers with β-cyclodextrin
    Obaid A, Jamil AKM, Prabu S, Saharin SM, Mohamad S
    Spectrochim Acta A Mol Biomol Spectrosc, 2020 Nov 05;241:118674.
    PMID: 32652287 DOI: 10.1016/j.saa.2020.118674
    Inclusion complexes of R-ketoprofen and S-ketoprofen enantiomers with β-cyclodextrin (β-CD) in aqueous solution were studied using various spectroscopic techniques such as Raman, FTIR, UV and fluorescence. The different relative intensities and characteristic band shifts of the two enantiomers from Raman spectra suggests different interaction when complexed with β-CD. Raman experiments revealed a noticeable diminishing of the CC vibration and ring deformation, which indicate the embedding of ketoprofen inside the β-CD cavity. It's revealed that distinct differences between R- and S-ketoprofen in the presence of β-CD at neutral pH. The stoichiometry ratio and binding constant of the inclusion complexes were calculated using Benesi-Hildebrand plot. Both enantiomers showed stoichiometry ratio of 1:1 inclusion complex with β-CD. The binding constant of R-ketoprofen (4088 M-1) is higher than S-ketoprofen (2547 M-1). These values indicated that β-CD formed inclusion complexes more preferentially with R-ketoprofen than S-ketoprofen. Results demonstrated that β-CD can be used as a promising chiral selector for ketoprofen enantiomers.
    Matched MeSH terms: Vibration
  20. Fulltext Vibration-assisted forward osmosis process for Mao (Antidesma bunius L. Spreng) juice concentration: water flux enhancement and preservation of phytochemicals
    Sirinupong, T., Tirawat, D., Lau, W. J., Youravong, W.
    International Food Research Journal, 2020;27(6):1156-1166.
    MyJurnal
    The experimental water flux of the forward osmosis (FO) process is much lower than the
    theoretical flux due to the existence of the internal concentration polarisation (ICP), external
    concentration polarisation (ECP), and membrane fouling. In the present work, vibration was
    integrated with the FO process to enhance water flux in water and Mao (Antidesma bunius L.
    Spreng) juice concentration. In addition, the capability of the FO process in preserving
    phytochemicals was studied. The use of the vibration assisted technique could enhance the
    water flux up to 23% during the FO process of distilled water due to the reduction of ICP, and
    a much higher water flux enhancement (up to 70%) was attained during the FO of Mao juice
    due to the reduction of ICP, ECP, and fouling. Phytochemicals including total phenolic
    compounds, anthocyanin, and ascorbic acid were preserved up to 82.7, 72.6, and 95.9%,
    respectively. These results suggest that membrane vibration is a promising technique for the
    enhancement of the FO process performance.
    Matched MeSH terms: Vibration
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