Displaying publications 41 - 60 of 276 in total

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  1. Biocompatible chitin-encapsulated CdS quantum dots: Fabrication and antibacterial screening
    Lim MJ, Shahri NNM, Taha H, Mahadi AH, Kusrini E, Lim JW, et al.
    Carbohydr Polym, 2021 May 15;260:117806.
    PMID: 33712152 DOI: 10.1016/j.carbpol.2021.117806
    Chitin-encapsulated cadmium sulfide quantum dots (CdS@CTN QDs) were successfully synthesized from chitin and Cd(NO3)2 precursor using the colloidal chemistry method, toward the development of biocompatible and biodegradable QDs for biomedical applications. CdS@CTN QDs exhibited the nanocrystalline cubic CdS encapsulated by α-chitin. The average particle size of CdS@CTN QDs was estimated using empirical Henglein model to be 3.9 nm, while their crystallite size was predicted using Scherrer equation to be 4.3 nm, slightly larger compared to 3-mercaptopropionic acid-capped CdS QDs (3.2 and 3.6 nm, respectively). The mechanism of formation was interpreted based on the spectroscopic data and X-ray crystal structures of CdS@CTN QDs fabricated at different pH values and mass ratios of chitin to Cd(NO3)2 precursor. As an important step to explore potential biomolecular and biological applications of CdS@CTN QDs, their antibacterial activities were tested against four different bacterial strains; i.e. Escherichia coli, Bacillus subtillus, Staphylococcus aureus and Pseudomonas aeruginosa.
    Matched MeSH terms: X-Rays
  2. Biological polymeric shielding design for an X-ray laboratory using Monte Carlo codes
    Tajudin SM, Tabbakh F
    Radiol Phys Technol, 2019 Sep;12(3):299-304.
    PMID: 31302871 DOI: 10.1007/s12194-019-00522-w
    Photon irradiation facilities are often shielded using lead despite its toxicity and high cost. In this study, three Monte Carlo codes, EGS5, MCNPX, and Geant4, were utilized to investigate the efficiency of a relatively new polymeric base compound (CnH2n), as a radiation shielding material for photons with energies below 150 keV. The proposed compound with the densities of 6 and 8 g cm-3 were doped with the weight percentages of 8.0 and 15.0% gadolinium. The probabilities of photoelectric effect and Compton scattering were relatively equal at low photon energies, thus the shielding design was optimized using three Monte Carlo codes for the conformity of calculation results. Consequently, 8% Gd-doped polymer with thickness less than 2 cm and density of 6 g cm-3 was adequate for X-ray room shielding to attenuate more than 95% of the 150-keV incident photons. An average dose rate reduction of 88% can be achieved to ensure safety of the radiation area.
    Matched MeSH terms: X-Rays/adverse effects
  3. Biomineralized Conductive PEDOT: PSS-Coated PLA/PHBV/HA Nanofibrous Membranes
    Hassan MI, Masnawi NN, Sultana N
    ASAIO J., 2017 9 14;64(3):415-423.
    PMID: 28901994 DOI: 10.1097/MAT.0000000000000655
    Conductive materials are potential candidates for developing bone tissue engineering scaffolds as they are nontoxic and can enhance bone tissue regeneration. Their bioactivity can be enhanced by depositing biomineralization in simulated body fluid (SBF). In the current study, a composite electrospun membrane made up of poly(lactic) acid, poly(3-hydroxybutyrate-co-3-hydroxyvalerate), and hydroxyapatite was fabricated using an electrospinning method. The fabricated membranes were dip-coated with a conductive polymer solution, poly(3,4-ethylenedioxythiophene) poly(4-styrenesulfonate), to induce conductivity. Characterization of the membranes based on characteristics such as morphology, chemical bonding, and wettability was conducted using scanning electron microscopy, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, attenuated total reflectance Fourier transform infrared spectroscopy, and contact angle measurement. From the results, biomineralization of both coated and noncoated composite membranes was observed on the surface of nanofibers after 21 days in SBF. The membranes provide a superhydrophilic surface as shown by the contact angle. In conclusion, this biomimetic electrospun composite membrane could be used to further support cell growth for bone tissue engineering application.
    Matched MeSH terms: X-Rays
  4. Fulltext COVID-19 Deep Learning Prediction Model Using Publicly Available Radiologist-Adjudicated Chest X-Ray Images as Training Data: Preliminary Findings
    Che Azemin MZ, Hassan R, Mohd Tamrin MI, Md Ali MA
    Int J Biomed Imaging, 2020;2020:8828855.
    PMID: 32849861 DOI: 10.1155/2020/8828855
    The key component in deep learning research is the availability of training data sets. With a limited number of publicly available COVID-19 chest X-ray images, the generalization and robustness of deep learning models to detect COVID-19 cases developed based on these images are questionable. We aimed to use thousands of readily available chest radiograph images with clinical findings associated with COVID-19 as a training data set, mutually exclusive from the images with confirmed COVID-19 cases, which will be used as the testing data set. We used a deep learning model based on the ResNet-101 convolutional neural network architecture, which was pretrained to recognize objects from a million of images and then retrained to detect abnormality in chest X-ray images. The performance of the model in terms of area under the receiver operating curve, sensitivity, specificity, and accuracy was 0.82, 77.3%, 71.8%, and 71.9%, respectively. The strength of this study lies in the use of labels that have a strong clinical association with COVID-19 cases and the use of mutually exclusive publicly available data for training, validation, and testing.
    Matched MeSH terms: X-Rays
  5. Fulltext Cardiac A-lines in fast scan as a sign of pneumopericardium
    Md Noor J, Eddie EA
    Ultrasound J, 2019 Apr 25;11(1):7.
    PMID: 31359168 DOI: 10.1186/s13089-019-0123-x
    BACKGROUND: Traumatic pneumopericardium is rare and usually results from blunt injury. Diagnosis through clinical and chest X-ray is often difficult. Ultrasound findings of A-line artifacts in the cardiac window may suggest pneumopericardium.

    CASE PRESENTATION: A young man involved in a car accident and sustained blunt thoracic injuries, among others. As part of primary survey, FAST scan was performed. Subxiphoid view to look for evidence of pericardial effusion showed part of the cardiac image obscured by A-lines. Other cardiac windows showed only A-lines, as well. A suspicion of pneumopericardium was raised and CT scan confirmed the diagnosis.

    CONCLUSIONS: Although FAST scan was originally used to look for presence of free fluid, with the knowledge of lung ultrasound for pneumothorax, our findings suggest that FAST scan can also be used to detect pneumopericardium.

    Matched MeSH terms: X-Rays
  6. Catalytic performance of Cu/ZnO/Al2O3/ZrO2 for slurry methanol synthesis from CO2 Hydrogenation: Effect of Cu/Zn Molar Ratio
    Salina Shaharun, Maizatul S. Shaharun, Mohamad F.M. Shah, Nurul A. Amer
    Sains Malaysiana, 2018;47:207-214.
    Catalytic hydrogenation of carbon dioxide (CO2) to methanol is an attractive way to recycle and utilize CO2. A series of Cu/ZnO/Al2O3/ZrO2 catalysts (CZAZ) containing different molar ratios of Cu/Zn were prepared by the co-precipitation method. The catalysts were characterized by temperature-programmed reduction (TPR), field emission scanning electron microscopy-energy dispersive x-ray analysis (FESEM-EDX) and X-ray diffraction (XRD). Higher surface area, SABET values (42.6-59.9 m2/g) were recorded at low (1) and high (5) Cu/Zn ratios with the minimum value of 35.71 m2/g was found for a Cu/Zn of 3. The reducibility of the metal oxides formed after calcination of catalyst samples was also affected due to change in metal-support interaction. At a reaction temperature of 443 K, total gas pressure of 3.0 MPa and 0.1 g/mL of the CZAZ catalyst, the selectivity to methanol decreased as the Cu/Zn molar ratio increased, and the maximum selectivity of 93.9 was achieved at Cu/Zn molar ratio of 0.33. With a reaction time of 3h, the best performing catalyst was CZAZ75 with Cu/Zn molar ratio of 5 giving methanol yield of 6.4%.
    Matched MeSH terms: X-Rays
  7. Cellulose Supported Pd(II) Complex Catalyzed Carbon-Carbon Bonds Formation
    Sarkar SM, Rashid SS, Karim KMR, Mustapha SNH, Lian YM, Zamri N, et al.
    J Nanosci Nanotechnol, 2019 05 01;19(5):2856-2861.
    PMID: 30501791 DOI: 10.1166/jnn.2019.16289
    Corn-cobs are an agro-industrial waste and composed of cellulose mostly. In this study cellulose was isolated from the waste corn-cobs and modified to polymeric hydroxamic acid palladium complex 1 and characterized by using a variety of spectroscopic methods such as field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and inductively coupled plasma atomic emission spectroscopy (ICP-AES). The complex 1 exhibited high catalytic activity towards Suzuki and Heck coupling reactions of activated and deactivated aryl halides to give the respective coupling products with high yield. Moreover, the complex 1 was recovered and recycled five times with no considerable loss of catalytic overall performance.
    Matched MeSH terms: X-Rays
  8. Characterisation of micro-sized and nano-sized tungsten oxide-epoxy composites for radiation shielding of diagnostic X-rays
    Azman NZ, Siddiqui SA, Low IM
    Mater Sci Eng C Mater Biol Appl, 2013 Dec 1;33(8):4952-7.
    PMID: 24094209 DOI: 10.1016/j.msec.2013.08.023
    Characteristics of X-ray transmissions were investigated for epoxy composites filled with 2-10 vol% WO3 loadings using synchrotron X-ray absorption spectroscopy (XAS) at 10-40 keV. The results obtained were used to determine the equivalent X-ray energies for the operating X-ray tube voltages of mammography and radiology machines. The results confirmed the superior attenuation ability of nano-sized WO3-epoxy composites in the energy range of 10-25 keV when compared to their micro-sized counterparts. However, at higher synchrotron radiation energies (i.e., 30-40 keV), the X-ray transmission characteristics were similar with no apparent size effect for both nano-sized and micro-sized WO3-epoxy composites. The equivalent X-ray energies for the operating X-ray tube voltages of the mammography unit (25-49 kV) were in the range of 15-25 keV. Similarly, for a radiology unit operating at 40-60 kV, the equivalent energy range was 25-40 keV, and for operating voltages greater than 60 kV (i.e., 70-100 kV), the equivalent energy was in excess of 40 keV. The mechanical properties of epoxy composites increased initially with an increase in the filler loading but a further increase in the WO3 loading resulted in deterioration of flexural strength, modulus and hardness.
    Matched MeSH terms: X-Rays
  9. Characteristics and performance of a mesoporous cerium-aluminum-silver mixed oxide for removal of methyl Violet Dye
    Phatai P, Srisomang R
    Sains Malaysiana, 2016;45:1477-1485.
    In this study, the adsorption efficiency of methyl violet (MV) dye onto Ce0.3Al0.7 and Ce0.3Al0.7Agx (x = 0.1, 0.3 & 0.5) mixed oxides was investigated. The properties of mixed oxide were determined by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), N2 adsorption-desorption isotherm, diffuse reflectance UV-vis spectroscopy (UV-vis DRS) and X-ray absorption near edge structure (XANES). Characterization showed that synthesized mixed oxide with fluorite has a pure cubic structure of a mesoporous nature and a small grain size with rough surface. Batch adsorption experiments were used to study parameters including contact time and initial dye concentration. The results showed that these parameters affected the degree of MV dye adsorption. The dye adsorption of mixed oxides attained equilibrium at 120 min. The equilibrium adsorption data were analyzed using Langmuir, Freundlich and Temkin isotherms. The adsorption behavior of MV dye onto Ce0.3Al0.7 was found to follow the Langmuir isotherm (R2 = 0.9951), providing a maximum monolayer adsorptive capacity of 2.35 mg/g. Alternatively, the adsorption of MV dye onto Ce0.3Al0.7Ag0.1 (R2 = 0.7839), Ce0.3Al0.7Ag0.3 (R2 = 0.9301) and Ce0.3Al0.7Ag0.5 (R2 = 0.9396) followed the Freundlich isotherm. The possible adsorption mechanisms of MV dyes onto the Ce0.3Al0.7 and Ce0.3Al0.7Agx were also discussed.
    Matched MeSH terms: X-Rays
  10. Characteristics of nanostructured CaxZn(I_x)Al204 thin films prepared by sol-gel method for GPS patch antennas
    Wan Nasarudin Wan Jalal, Huda Abdullah, Mohd Syafiq Zulfakar, Sahbudin Shaari, Mohammad Thariqul Islam, Badariah Bais
    Sains Malaysiana, 2014;43:833-842.
    CaxZn(1_x)Al204thin films (x = 0.00; 0 .05 ; 0.10; 0.15 and 0.20) were prepared by sol-gel method with the substitution of Zn2+ by Ca" in the framework of ZnAl204. The effect of Ca addition on the structure and morphology of CaZnAl204thin films was investigated by x-ray diffraction (xRD), field-emission scanning electron microscope (FESEM), energy-dispersive x-ray spectroscopy (EDx), ultra-violet visible (uv-Vis) and atomic force microscope (AFM). The xRD patterns showed the characteristic peaks of face-centred cubic (fcc)ZnAl204and CaZnAl204. The addition of Ca increased the crystallite size from 8.9 to 302 nm. The bandgap of CaxZnuld204 thin film was found in the range of 3.40 to 3.84 eV. sEm micrograph shows the morphology of all thin films is sphere-like, with the grain size increased from 33 to 123 nm. The AFM images show the roughness of surface morphology increased. The substitution of Zn2+ by Ca" increased the crystallite size, grain size and surface roughness which evidently increased the density (4.59 to 4.64 glcm3) and dielectric constant (8.48 to 9.54). The composition of CaxZn(1_x)Al204is considered as suitable material for GPS patch antennas.
    Matched MeSH terms: X-Rays
  11. Fulltext Characterization data of titanate compounds synthesized using hydrothermal method at various temperature
    Razali MH, Ismail NA, Osman UM, Rozaini MZH, Yusoff M
    Data Brief, 2020 Feb;28:104992.
    PMID: 31890823 DOI: 10.1016/j.dib.2019.104992
    Titanate compounds was synthesized using hydrothermal method at various temperature (100, 150, 200, and 250 °C) for 24 hours. As-synthesized titanate was characterized using FTIR, XRD and nitrogen gas adsorption. FTIR spectra was scanned from 4000 to 400 cm-1 using Perkin Elmer Spectrum 100 FTIR spectrophotometer. XRD diffractogram was performed by using Rigaku Miniflex (II) X-ray diffractometer operating at a scanning rate of 2.00° min-1. The diffraction spectra were recorded at the diffraction angle, 2θ from 10° to 80° at room temperature. Nitrogen gas adsorption analysis was studied by using Micromeritics ASAP2020 (Alaska) to determine the surface area and pores size distribution. The nitrogen adsorption and desorption was measured at 77 K (temperature of liquid nitrogen) and the samples were degassed in a vacuum at 110 °C under nitrogen flow for overnight prior to analysis.
    Matched MeSH terms: X-Rays
  12. Fulltext Characterization of COOH-Fe3O4/NCC-CTA+ on screen printed carbon electrode using field emission scanning electron microscope and energy dispersive X-Ray for DNA biosensor
    Che Engku Noramalina Che-Engku-Chik, Nor Azah Yusof, Jaafar Abdullah, Siti Sarah Othman, Helmi Wasoh
    Journal of Biochemistry, Microbiology and Biotechnology, 2017;5(2):19-21.
    MyJurnal
    A novel DNA biosensing platform was designed by the functionalization of iron oxide (Fe3O4)
    with the carboxylic group via capping agent, mercaptopropionic acid (MPA) and conjugated
    with nanocellulose crystalline (NCC) surface modified with surfactant cetyltrimethylammonium
    bromide (CTAB) to assist in the DNA sensing capability. The product of nanocomposites
    compound was drop-casted on screen printed carbon electrode (SPCE). Characterization by field
    emission scanning electron microscope (FESEM) and energy dispersive X-Ray (EDX)
    spectroscopy showing that carboxyl functionalized iron oxide (COOH-Fe3O4) can be hybridized
    with NCC-CTA+ via electrostatic interaction.
    Matched MeSH terms: X-Rays
  13. Characterization of Microcrystalline Cellulose Isolated from Conocarpus Fiber
    Fouad H, Kian LK, Jawaid M, Alotaibi MD, Alothman OY, Hashem M
    Polymers (Basel), 2020 Dec 07;12(12).
    PMID: 33297332 DOI: 10.3390/polym12122926
    Conocarpus fiber is an abundantly available and sustainable cellulosic biomass. With its richness in cellulose content, it is potentially used for manufacturing microcrystalline cellulose (MCC), a cellulose derivative product with versatile industrial applications. In this work, different samples of bleached fiber (CPBLH), alkali-treated fiber (CPAKL), and acid-treated fiber (CPMCC) were produced from Conocarpus through integrated chemical process of bleaching, alkaline cooking, and acid hydrolysis, respectively. Characterizations of samples were carried out with Scanning Electron Microscope (SEM), Energy Dispersive X-ray (EDX), Fourier Transform Infrared-Ray (FTIR), X-ray Diffraction (XRD), Thermogravimetric (TGA), and Differential Scanning Calorimetry (DSC). From morphology study, the bundle fiber feature of CPBLH disintegrated into micro-size fibrils of CPMCC, showing the amorphous compounds were substantially removed through chemical depolymerization. Meanwhile, the elemental analysis also proved that the traces of impurities such as cations and anions were successfully eliminated from CPMCC. The CPMCC also gave a considerably high yield of 27%, which endowed it with great sustainability in acting as alternative biomass for MCC production. Physicochemical analysis revealed the existence of crystalline cellulose domain in CPMCC had contributed it 75.7% crystallinity. In thermal analysis, CPMCC had stable decomposition behavior comparing to CPBLH and CPAKL fibers. Therefore, Conocarpus fiber could be a promising candidate for extracting MCC with excellent properties in the future.
    Matched MeSH terms: X-Rays
  14. Characterization of soy-lignin bonded Rhizophora spp. particleboard as substitute phantom material for radiation dosimetric studies - Investigation of CT number, mass attenuation coefficient and effective atomic number
    Zuber SH, Hashikin NAA, Mohd Yusof MF, Aziz MZA, Hashim R
    Appl Radiat Isot, 2021 Apr;170:109601.
    PMID: 33515930 DOI: 10.1016/j.apradiso.2021.109601
    Experimental particleboards are made from Rhizophora spp. wood trunk with three different percentages of lignin and soy flour (0%, 6% and 12%) as adhesives. The objective was to investigate the equivalence of Rhizophora spp. particleboard as phantom material with human soft tissue using Computed Tomography (CT) number. The linear and mass attenuation coefficient of Rhizophora spp. particleboard at low energy range was also explored using X-ray Fluorescence (XRF) configuration technique. Further characterization of the particleboard was performed to determine the effective atomic number, Zeff using Energy Dispersive X-Ray (EDX) method. Adhesive-bonded Rhizophora spp. particleboard showed close similarities with water, based on the average CT numbers, electron density calibration curve and the analysis of CT density profile, compared to the binderless particleboard. The effective atomic number obtained from the study indicated that the attenuation properties of all the particleboards at different percentages of adhesives were almost similar to water. The mass attenuation coefficient calculated from XRF configuration technique showed good agreement with water from XCOM database, suggesting its potential as phantom material for radiation study.
    Matched MeSH terms: X-Rays
  15. Fulltext Characterization of the Acid-Base Character of Burned Clay Ceramics Used for Water Decontamination
    Sandu AV, Vasilache V, Sandu IG, Sieliechi JM, Kouame IK, Matasaru PD, et al.
    Materials (Basel), 2019 Nov 21;12(23).
    PMID: 31766445 DOI: 10.3390/ma12233836
    The paper presents the results of ample investigations performed on industrial and traditional ceramics of fired clay used in processes of water potabilization in the last stage of filtration, after that of active charcoal. Using the data obtained through the scanning electron microscope coupled with energy dispersive X-ray analysis (SEM-EDX) and pH analyses, on the basis of the atomic composition and free concentration of hydronium ions, the normal caustic (Si/Al) and summative [(Si+Ti+FeIII+Cl)/(Al+Ca+Mg+Na+K)] modules were assessed, which were correlated with the free acidity and, respectively, the capacity of absorption and ionic exchange of the Fe3+ and Al3+ ions. The study allowed the selection, on the basis of the caustic module, of the ceramics with high capacity for ionic exchange.
    Matched MeSH terms: X-Rays
  16. Chemically modified multi-walled carbon nanotubes (MWCNTs) with anchored acidic groups
    Nuruzatulifah Bt Asari @ Mansor, Tessonnier JP, Rinaldi A, Reiche S, Kutty M
    Sains Malaysiana, 2012;41:603-609.
    Surface functionalization of multi-walled carbon nanotubes (MWCNTs) was carried out using a gas phase treatment in a Universal Temperature Program (UTP) reactor by flowing SO3 gas onto the CNTs while being heated at different temperatures. The functionalized nanotubes were characterized using X-ray Fluorescence (XRF), Fourier Transform Infrared Spectroscopy (FT-IR) and Raman spectroscopy. The amount of oxyen and sulfur containing groups was determined by acid-base titration. The titration results were in good agreement with elemental analysis using x-ray fluorescence. FTIRanalysis showed the presence of oxygen and sulfur containing groups, S=O, C-S, C=O and -COOH. Raman spectroscopy confirmed that oxygen and sulfur containing acidic groups covalently attached to the sidewall of the MWCNTs.
    Matched MeSH terms: X-Rays
  17. Fulltext Chest x-ray as an essential part of routine medical examination: is it necessary?
    Izamin I, Rizal AM
    Med J Malaysia, 2012 Dec;67(6):606-9.
    PMID: 23770954 MyJurnal
    INTRODUCTION: Various studies in primary care and hospitalized patients have discouraged routine use of chest x-ray (CXR) in medical examination.
    PURPOSE: The study aims to determine the prevalence of abnormal routine CXR and cost of one CXR at a public health clinic and discuss the rationale of CXR in routine medical examination.
    METHODOLOGY: Data of patients who visited Klinik Kesihatan Bandar Kota Bharu (KKBKB), a public health clinic, from 1 January until 31 December 2010 were examined. The study used cross-sectional design. All patients who came for medical examination and CXR at KKBKB were included. Cost analysis was performed from the perspective of provider.
    FINDINGS: About 63.1% of 8315 CXR films in KKBKB were produced as part of routine medical examination. Prevalence of abnormal CXR was 0.25%. The cost of producing one CXR ranges from RM15.87 to RM32.34.
    DISCUSSION: Low yield from CXR screening and high cost of CXR are the main concern. CXR screening would also lead to unnecessary radiation; and false-positive screening resulting in physical risk, unwarranted anxiety and more expenditure. CXR screening is appropriately reserved for high-risk patients and those with relevant clinical findings.
    Matched MeSH terms: X-Rays
  18. Fulltext Comparative analyses of new donor-π-acceptor ferrocenyl-chalcones containing fluoro and methoxy-fluoro acceptor units as synthesized dyes for organic solar cell material
    Anizaim AH, Zainuri DA, Zaini MF, Razak IA, Bakhtiar H, Arshad S
    PLoS One, 2020;15(11):e0241113.
    PMID: 33147247 DOI: 10.1371/journal.pone.0241113
    Two organometallic compounds known as (E)-1-ferrocenyl-(3-fluorophenyl)prop-2-en-1-one (Fc1) and (E)-1-ferrocenyl-(3-fluoro-4-methoxyphenyl)prop-2-en-1-one (Fc2) are designed and synthesized for application in dye-sensitized solar cell (DSSC) based on a donor-π-acceptor (D-π-A) architecture. By strategically introducing a methoxy group into the acceptor side of the compound, Fc2 which has adopted a D-π-A-AD structure are compared with the basic D-π-A structure of Fc1. Both compounds were characterized by utilizing the IR, NMR and UV-Vis methods. Target compounds were further investigated by X-ray analysis and studied computationally using Density Functional Theory (DFT) and Time-Dependent DFT (TD-DFT) approaches to explore their potential performances in DSSCs. An additional methoxy group has been proven in enhancing intramolecular charge transfer (ICT) by improving the planarity of Fc2 backbone. This good electronic communication leads to higher HOMO energy level, larger dipole moment and better short-circuit current density (Jsc) values. Eventually, the presence of methoxy group in Fc2 has improved the conversion efficiency as in comparison to Fc1 under the same conditions.
    Matched MeSH terms: X-Rays
  19. Fulltext Comparison of Hook and Straight Steel Fibers Addition on Malaysian Fly Ash-Based Geopolymer Concrete on the Slump, Density, Water Absorption and Mechanical Properties
    Faris MA, Abdullah MMAB, Muniandy R, Abu Hashim MF, Błoch K, Jeż B, et al.
    Materials (Basel), 2021 Mar 09;14(5).
    PMID: 33803313 DOI: 10.3390/ma14051310
    Geopolymer concrete has the potential to replace ordinary Portland cement which can reduce carbon dioxide emission to the environment. The addition of different amounts of steel fibers, as well as different types of end-shape fibers, could alter the performance of geopolymer concrete. The source of aluminosilicate (fly ash) used in the production of geopolymer concrete may lead to a different result. This study focuses on the comparison between Malaysian fly ash geopolymer concrete with the addition of hooked steel fibers and geopolymer concrete with the addition of straight-end steel fibers to the physical and mechanical properties. Malaysian fly ash was first characterized by X-ray fluorescence (XRF) to identify the chemical composition. The sample of steel fiber reinforced geopolymer concrete was produced by mixing fly ash, alkali activators, aggregates, and specific amounts of hook or straight steel fibers. The steel fibers addition for both types of fibers are 0%, 0.5%, 1.0%, 1.5%, and 2.0% by volume percentage. The samples were cured at room temperature. The physical properties (slump, density, and water absorption) of reinforced geopolymer concrete were studied. Meanwhile, a mechanical performance which is compressive, as well as the flexural strength was studied. The results show that the pattern in physical properties of geopolymer concrete for both types of fibers addition is almost similar where the slump is decreased with density and water absorption is increased with the increasing amount of fibers addition. However, the addition of hook steel fiber to the geopolymer concrete produced a lower slump than the addition of straight steel fibers. Meanwhile, the addition of hook steel fiber to the geopolymer concrete shows a higher density and water absorption compared to the sample with the addition of straight steel fibers. However, the difference is not significant. Besides, samples with the addition of hook steel fibers give better performance for compressive and flexural strength compared to the samples with the addition of straight steel fibers where the highest is at 1.0% of fibers addition.
    Matched MeSH terms: X-Rays
  20. Fulltext Comparison of direct method and indirect methods for sampling and analysis of airborne respirable crystaline silica by X-ray difractometer
    Suhaily Amran, Ahmad Sayuti Zainal Abidin, Shoffian Amin Jaafar, Mohd Talib Latif, Abdul Mutalib Leman
    Journal of Occupational Safety and Health, 2015;12(1):137-141.
    MyJurnal
    There are several alternative sampling and analytical methods available for the determination of respirable
    crystalline silica exposure among workers. The commonly used ones are, (1) NIOSH Manual Analytical Method
    No.7500(NMAM 7500) which is Silica, crystalline, by X-ray difractometer via filter deposition(NIOSH 2003), and
    (2) MDHS 101 (Methods for the Determination of Hazardous Substances (MDHS) Guidance No.101: Respirable
    crystalline silica in respirable airborne dust). The aim of this study is to compare applicability of respirable crystalline
    silica sampling and analysis between method MDHS 101 and NMAM 7500. Laboratory procedures will be performed
    strictly based on MDHS 101 and NMAM 7500. Both methods apply X-ray diffraction as analytical technique with
    many variations on sampling techniques and laboratory preparations. Quality assurance values such as detection
    limits, accuracy and precision are derived from both data and will be compared to determine which of the method
    establishes better quality assurance. The method which establishes better quality assurance will be recommend to be
    used in Malaysian respirable crystalline silica monitoring programme. The strength of this research lies on its potential
    to provide local capabilities in analysis of respirable crystalline silica in Malaysian setting.
    Matched MeSH terms: X-Rays
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