Displaying publications 1 - 20 of 625 in total

  1. Palaniandy, Samayamutthirian, Khairun Azizi Mohd Azizli, Hashim Hussin, Syed Fuad Saiyid Hashim
    Mechanical activation of quartz was carried out in jet mill at various specific kinetic energy level and classifier speed. The characterization of the particle size, crystallite size, amorphism rate and lattice strain was conducted on the feed and mechanically activated particles. The area under the prominent quartz peak was used to calculate the amorphism rate of the mechanically activated particles. Scherer equation was used to determine the crystallite size of the feed and mechanically activated particles. Mean particle size less than 5μm was obtained when the specific kinetic energy is ranging between 500 kWh/ton and 1000 kWh/ton. Amorphism of the mechanically activated particles up to 18% was observed at 500 kWh/ton. The crystallite size and lattice strain is influence by the intensity of the specific kinetic energy and classifier speed. The reduction in the crystallite size up to 39% was observed where the minimum crystallite is 23nm. The lattice strain is ranging from 0.024 to 0.038 respective to the specific kinetic energy and classifier speed.
    Matched MeSH terms: Particle Size
  2. Irzaman, Jamal, Z., Idris, M.S., Kurnia, D., Barmawi, M.
    The specimens used were CaCO3 (Sigma Aldrich, purity 99.9 %). We have 23 parameters and 20 iterations, including two theta zero error, scale factor, thermal effect, coefficients for polynomial describing the background; U, V, W and mixing parameters of the profile peak function, lattice constants, positional parameters and overall isotropic temperature factors. Most the samples show that the crystal structure are rhombohedral with lattice constants a = b = 4.981 Å, c = 17.044 Å and space group is R3C. The microstrain (K) and the particle size (V) of CaCO3 ceramic were calculated using 10 the full width at half maximum (FWHM) of diffraction peaks from (0 1 2), (1 0 4), (0 0 6), (1 1 0), (1 1 3), (2 0 2), (0 1 8), (1 1 6), (2 2 1 ), (1 2 2) crystal planes are 2.1 x 10-2 and
    362 nm, respectively.
    Matched MeSH terms: Particle Size
  3. Dahalan FA, Abdullah N, Yuzir A, Olsson G, Salmiati, Hamdzah M, et al.
    Bioresour Technol, 2015 Apr;181:291-6.
    PMID: 25661308 DOI: 10.1016/j.biortech.2015.01.062
    Aerobic granulation is increasingly used in wastewater treatment due to its unique physical properties and microbial functionalities. Granule size defines the physical properties of granules based on biomass accumulation. This study aims to determine the profile of size development under two physicochemical conditions. Two identical bioreactors namely Rnp and Rp were operated under non-phototrophic and phototrophic conditions, respectively. An illustrative scheme was developed to comprehend the mechanism of size development that delineates the granular size throughout the granulation. Observations on granules' size variation have shown that activated sludge revolutionised into the form of aerobic granules through the increase of biomass concentration in bioreactors which also determined the changes of granule size. Both reactors demonstrated that size transformed in a similar trend when tested with and without illumination. Thus, different types of aerobic granules may increase in size in the same way as recommended in the aerobic granule size development scheme.
    Matched MeSH terms: Particle Size*
  4. Mohamad N, Ubaidillah, Mazlan SA, Choi SB, Abdul Aziz SA, Sugimoto M
    Int J Mol Sci, 2019 Mar 27;20(7).
    PMID: 30934679 DOI: 10.3390/ijms20071525
    The transient response of magnetorheological (MR) materials, in general, is very important for design consideration in MR-based devices. Better response to magnetic fields is beneficial for a better response rate to the electrical current applied in the electromagnetic coil. As a result, MR-based devices would have a high response to external stimuli. In this work, the principal characteristics of magnetorheological greases (MRGs) which have two different particle shapes are experimentally investigated. One type of particle distributed in the grease medium is conventional spherical-shaped carbonyl iron (CI) particles, while the other is plate-like CI particles made using a high-energy rotary ball mill from spherical CI particles. A set of bidisperse MRG samples are firstly prepared by adjusting the weight percentage of the plate-like CI particles and mixing with the spherical CI particles. Subsequently, three important properties of MRGs in terms of their practical application are measured and compared between the two different particle shapes. The field-dependent apparent viscoelastic properties of the prepared MRG samples are measured, followed by the field-dependent storage and loss moduli using an oscillatory shear rheometer. In addition, the transient response time, which indicates the speed in the actuating period of MRGs, is measured by changing the strain amplitude. Then, a comparative assessment on the three properties are undertaken between two different particle shapes by presenting the corresponding results in the same plot. It is shown that the bidisperse MRG with plate-like CI particles exhibits an increase in the initial apparent viscosity as well as stiffness property compared to the MRG with spherical particles only.
    Matched MeSH terms: Particle Size*
  5. Xu LL, Zhang HF, Li M, Ng SW, Feng JH, Mao JG, et al.
    J Am Chem Soc, 2018 09 19;140(37):11569-11572.
    PMID: 30141923 DOI: 10.1021/jacs.8b06725
    Chiroptical activity is observed from an achiral adenine-containing metal-organic framework (MOF) named ZnFDCA. Such a seemingly counterintuitive phenomenon can, in fact, be predicted by the intrinsic crystal symmetry of 4̅2 m point group. Although theoretically allowed, examples of optically active achiral crystals are extremely rare. ZnFDCA is the first reported achiral MOF showing optical activity, as demonstrated by a pair of circular dichroism signals with opposite signs and enhanced intensity. Moreover, simply through adding an amino substituent to adenine, the chiroptical activity, as well as nonlinear optical activity, of the analogous MOF, namely ZnFDCA-NH2, disappears due to diverse packing pattern giving rise to centrosymmetric crystal symmetry.
    Matched MeSH terms: Particle Size
  6. Ng SK, Nyam KL, Nehdi IA, Chong GH, Lai OM, Tan CP
    Food Sci Biotechnol, 2016;25(Suppl 1):15-21.
    PMID: 30263481 DOI: 10.1007/s10068-016-0093-8
    β-Lactoglobulin (β-lg) can produce fibrils that have multi-functional properties. Impacts of different stirring speeds on characteristics of β-lg fibrils as a stable form in β-lg fibril solutions were investigated. Fibril concentration, fibril morphology, turbidity, particle size distribution, zeta potential, and rheological behavior of solutions were studied. Stirring enhanced fibril formation and stability of a fibril solution, in comparison with unstirred solutions. Increasing the stirring speed produced more turbidity and a greater distribution of particle sizes, higher viscosity values, but no differences in zeta potential values of β-lg fibril solutions. However, a high stirring speed is not feasible due to reduction of the fibril yield and changes in fibril morphology.
    Matched MeSH terms: Particle Size
  7. Majid AMA, Rahiman MHF, Wong TW
    Int J Pharm, 2021 Aug 10;605:120786.
    PMID: 34111546 DOI: 10.1016/j.ijpharm.2021.120786
    This study developed a tester where the powder flow was characterized using a low sample mass (2 g) and impact instead of dispersion mechanism to mitigate test space constraint. An impact chamber was established where the test powder bed of seven lactose grades was weight-impacted to produce impact crater and ejecta, and imaged quantitatively to determine crater profiling signature (crater depth), regional topography (ejecta roughness), Otsu threshold (bed continuity) and edge segmentation (bed deformation). The Hausner ratio (HR) and Carr's index (CI) values of lactose, and their powder dispersion distance and surface area characteristics evaluated by gas-pressurized dispersibility test were examined as reference method. The crater signature profiling and regional topography were correlated to HR, CI, dispersive distance and surface area. A poorer powder flow was characterized by higher values of crater signature profiling, regional topography, HR, CI, and lower dispersive distance and surface area. The crater signature profiling and regional topography values were higher with smaller and rougher lactose particles that were cohesive. The powder impact flow is a viable non-dispersive approach to characterize powder flowability using a small sample mass and test space.
    Matched MeSH terms: Particle Size
  8. Chen WH, Chang CM, Mutuku JK, Lam SS, Lee WJ
    J Hazard Mater, 2021 08 15;416:125856.
    PMID: 34492805 DOI: 10.1016/j.jhazmat.2021.125856
    Inhalation of aerosols such as pharmaceutical aerosols or virus aerosol uptake is of great concern to the human population. To elucidate the underlying aerosol dynamics, the deposition fractions (DFs) of aerosols in healthy and asthmatic human airways of generations 13-15 are predicted. The Navier-stokes equations governing the gaseous phase and the discrete phase model for particles' motion are solved using numerical methods. The main forces responsible for deposition are inertial impaction forces and complex secondary flow velocities. The curvatures and sinusoidal folds in the asthmatic geometry lead to the formation of complex secondary flows and hence higher DFs. The intensities of complex secondary flows are strongest at the generations affected by asthma. The DF in the healthy airways is 0%, and it ranges from 1.69% to 52.93% in the asthmatic ones. From this study, the effects of the pharmaceutical aerosol particle diameters in the treatment of asthma patients can be established, which is conducive to inhibiting the inflammation of asthma airways. Furthermore, with the recent development of COVID-19 which causes pneumonia, the predicted physics and effective simulation methods of bioaerosols delivery to asthma patients are vital to prevent the exacerbation of the chronic ailment and the epidemic.
    Matched MeSH terms: Particle Size
  9. Karami A, Golieskardi A, Keong Choo C, Larat V, Galloway TS, Salamatinia B
    Sci Rep, 2017 04 06;7:46173.
    PMID: 28383020 DOI: 10.1038/srep46173
    The occurrence of microplastics (MPs) in saltwater bodies is relatively well studied, but nothing is known about their presence in most of the commercial salts that are widely consumed by humans across the globe. Here, we extracted MP-like particles larger than 149 μm from 17 salt brands originating from 8 different countries followed by the identification of their polymer composition using micro-Raman spectroscopy. Microplastics were absent in one brand while others contained between 1 to 10 MPs/Kg of salt. Out of the 72 extracted particles, 41.6% were plastic polymers, 23.6% were pigments, 5.50% were amorphous carbon, and 29.1% remained unidentified. The particle size (mean ± SD) was 515 ± 171 μm. The most common plastic polymers were polypropylene (40.0%) and polyethylene (33.3%). Fragments were the primary form of MPs (63.8%) followed by filaments (25.6%) and films (10.6%). According to our results, the low level of anthropogenic particles intake from the salts (maximum 37 particles per individual per annum) warrants negligible health impacts. However, to better understand the health risks associated with salt consumption, further development in extraction protocols are needed to isolate anthropogenic particles smaller than 149 μm.
    Matched MeSH terms: Particle Size
  10. Wang G, Pu X
    Sains Malaysiana, 2014;43:807-812.
    A distinct element approach has been introduced for simulating the plugging performance of granular lost circulation materials (LCM) in a fracture. This approach solves the fully coupled fracture walls, fluid and particles system in an interactive environment. The effects of the particle shape, size distribution and concentration on the fracture-plugging performance of the granular LCM have been investigated using the three-dimensional particle flow code (PFC3D). The simulated results showed that the irregular granular LCM could plug a fracture width larger than the sieving granulation by single-particle bridging type. The particle size distribution (PSD) of LCM dominates the plugging depth and efficiency in a fracture and there exists an optimum concentration for maximum effect of LCM additives.
    Matched MeSH terms: Particle Size
  11. Rashid M, Huda N, Norelyza H, Hasyimah N
    Sains Malaysiana, 2015;44:565-569.
    A new type of cyclone design configuration called MR-deDuster, which contains multi cyclone, has been developed.
    A theoretical study had been carried out to evaluate and predict the performance of a MR-deDuster. In this paper, a
    comparative study was done to investigate the performance of MR-deDuster with other conventional cyclones in terms
    of collection efficiency and pressure drop. The performance of MR-deDuster was measured by its collection efficiency
    based on the particle size distribution of activated carbon. It was found that MR-deDuster is able to collect as high as
    94% of PM10 which is high comparing with many other conventional cyclones. In addition, the pressure drop of the unit
    is relatively low compared to the other cyclones which highlight the ability of the unit to capture the fine particle at low
    pressure drop.
    Matched MeSH terms: Particle Size
  12. Yusrabbil Amiyati Yusof, Zafarizal Aldrin Azizul Hasan, Azhar Ariffin
    Sains Malaysiana, 2018;47:511-515.
    This paper reports the effects of glyceryl ether specifically mono-tert-butoxypropanediol on oil in water emulsion system.
    Based on 12 HLB value, screening for stable emulsions was carried out without the presence of glyceryl ether. A stable
    emulsion was used as a control. Then the effects of glyceryl ether on the emulsion system were investigated. The emulsions
    prepared were analyzed for stability, viscosity, pH value, particle size, in vitro dermal irritation potential, in vitro ocular
    irritation potential and also moisturizing property. The incorporation of glycerol in the emulsion system was also done
    for comparison. Emulsions with glyceryl ether showed lower viscosity values than emulsions with glycerol. Furthermore,
    the emulsions also exhibited moisturizing property compared to the control emulsion. Glyceryl ether is suitable to be
    used in cosmetic products which require reduced viscosity but retain its skin hydration property.
    Matched MeSH terms: Particle Size
  13. Goh KB, Li Z, Chen X, Liu Q, Wu T
    J Colloid Interface Sci, 2022 Feb 15;608(Pt 2):1999-2008.
    PMID: 34749148 DOI: 10.1016/j.jcis.2021.10.092
    HYPOTHESIS: The performance of a polymeric core-shell microreactor depends critically on (i) mass transfer, (ii) catalyzed chemical reaction, and (iii) deactivation within the nonuniform core-shell microstructure environment. As such, these three basic working principles control the active catalytic phase density in the reactor.

    THEORY: We present a high-fidelity, image-based nonequilibrium computational model to quantify and visualize the mass transport as well as the deactivation process of a core-shell polymeric microreactor. In stark contrast with other published works, our microstructure-based computer simulation can provide a single-particle visualization with a micrometer spatial accuracy.

    FINDINGS: We show how the interplay of kinetics and thermodynamics controls the product-induced deactivation process. The model predicts and visualizes the non-trivial, spatially resolved active catalyst phase patterns within a core-shell system. Moreover, we also show how the microstructure influences the formation of foulant within a core-shell structure; that is, begins from the core and grows radially onto the shell section. Our results suggest that the deactivation process is highly governed by the porosity/microstructure of the microreactor as well as the affinity of the products towards the solid phase of the reactor.

    Matched MeSH terms: Particle Size
  14. Nine MJ, Choudhury D, Hee AC, Mootanah R, Osman NAA
    Materials (Basel), 2014 Feb 10;7(2):980-1016.
    PMID: 28788496 DOI: 10.3390/ma7020980
    Wear debris, of deferent sizes, shapes and quantities, generated in artificial hip and knees is largely confined to the bone and joint interface. This debris interacts with periprosthetic tissue and may cause aseptic loosening. The purpose of this review is to summarize and collate findings of the recent demonstrations on debris characterization and their biological response that influences the occurrence in implant migration. A systematic review of peer-reviewed literature is performed, based on inclusion and exclusion criteria addressing mainly debris isolation, characterization, and biologic responses. Results show that debris characterization largely depends on their appropriate and accurate isolation protocol. The particles are found to be non-uniform in size and non-homogeneously distributed into the periprosthetic tissues. In addition, the sizes, shapes, and volumes of the particles are influenced by the types of joints, bearing geometry, material combination, and lubricant. Phagocytosis of wear debris is size dependent; high doses of submicron-sized particles induce significant level of secretion of bone resorbing factors. However, articles on wear debris from engineered surfaces (patterned and coated) are lacking. The findings suggest considering debris morphology as an important parameter to evaluate joint simulator and newly developed implant materials.
    Matched MeSH terms: Particle Size
  15. Putra NR, Rizkiyah DN, Aziz AHA, Mamat H, Jusoh WMSW, Idham Z, et al.
    Sci Rep, 2023 Jul 05;13(1):10871.
    PMID: 37407592 DOI: 10.1038/s41598-023-32181-8
    The purpose of this work was to establish the best particle size for recovering high yields of total phenolic compounds (TPC), total anthocyanin compounds(TAC) and total flavonoid compounds (TFC) from roselle (Hibiscus sabdariffa) by applying supercritical carbon dioxide (ScCO2). The extraction rate, diffusivity and solubility of yield in ScCO2 were also studied and calculated utilizing models. Pressure (10 and 30 MPa), temperature (40 and 60 °C), and particle size (250 µm size of 250 µm size of roselle provides the maximum bioactive compound recovery and solubility. Furthermore, the diffusivity and extraction of ScCO2 are increased by decreasing the particle size. Therefore, a smaller particle size is appropriate for roselle extraction by ScCO2 based on the experimental and modelling data.
    Matched MeSH terms: Particle Size
  16. Gharibshahi E, Saion E
    Int J Mol Sci, 2012;13(11):14723-41.
    PMID: 23203091 DOI: 10.3390/ijms131114723
    Attempts to produce colloidal platinum nanoparticles by using steady absorption spectra with various chemical-based reduction methods often resulted in the fast disappearance of the absorption maxima leaving reduced platinum nanoparticles with little information on their optical properties. We synthesized colloidal platinum nanoparticles in an aqueous solution of polyvinyl pyrrolidone by gamma radiolytic reduction method, which produced steady absorption spectra of fully reduced and highly pure platinum nanoparticles free from by-product impurities or reducing agent contamination. The average particle size was found to be in the range of 3.4–5.3 nm and decreased with increasing dose due to the domination of nucleation over ion association in the formation of metal nanoparticles by the gamma radiolytic reduction method. The platinum nanoparticles exhibit optical absorption spectra with two absorption peaks centered at about 216 and 264 nm and the peaks blue shifted to lower wavelengths with decreasing particle size. The absorption spectra of platinum nanoparticles were also calculated using quantum mechanical treatment and coincidently a good agreement was obtained between the calculated and measured absorption peaks at various particle sizes. This indicates that the 216 and 264-nm absorption peaks of platinum nanoparticles conceivably originated from the intra-band transitions of conduction electrons of (n = 5, l = 2) and (n = 6, l = 0) energy states respectively to higher energy states. The absorption energies, i.e., conduction band energies of platinum nanoparticles derived from the absorption peaks increased with increasing dose and decreased with increasing particle size.
    Matched MeSH terms: Particle Size*
  17. Thiry V, Clauss M, Stark DJ, Beudels-Jamar RC, Vercauteren Drubbel R, Nathan SKSS, et al.
    Folia Primatol., 2018;89(5):327-334.
    PMID: 30114703 DOI: 10.1159/000490794
    Reducing the size of food particles is crucial for herbivores. Seasonal dietary changes are known to influence animals' chewing efficiency. Proboscis monkeys (Nasalis larvatus) are foregut fermenters, with a high chewing efficiency allowing them to achieve very fine faecal particles. In this study, we investigated how proboscis monkeys' chewing efficiency varies between wet and dry seasons, hypothesising differences possibly related to diet change. Faecal particle size analysis is an established approach to estimate chewing efficiency in mammalian herbivores. We analysed 113 proboscis monkey faecal samples collected in the Lower Kinabatangan Wildlife Sanctuary, between 2015 and 2017. By following standard sieve analysis protocols, we measured a mean particle size MPS0.025-8 of 0.45 ± 0.14 mm, and confirmed a previous result that proboscis monkeys have a very low faecal MPS. This study highlights a seasonal influence on proboscis monkeys' chewing efficiency, with smaller MPS (better chewing efficiency) during the wet season. During that time of the year, individuals may potentially change their diet, as all faecal samples contained intact seeds. Whether the seasonal MPS difference in proboscis monkeys is smaller than in other colobines due to their "rumination" strategy remains to be investigated.
    Matched MeSH terms: Particle Size*
  18. Abedini A, Daud AR, Abdul Hamid MA, Kamil Othman N, Saion E
    Nanoscale Res Lett, 2013;8(1):474.
    PMID: 24225302 DOI: 10.1186/1556-276X-8-474
    This review presents an introduction to the synthesis of metallic nanoparticles by radiation-induced method, especially gamma irradiation. This method offers some benefits over the conventional methods because it provides fully reduced and highly pure nanoparticles free from by-products or chemical reducing agents, and is capable of controlling the particle size and structure. The nucleation and growth mechanism of metallic nanoparticles are also discussed. The competition between nucleation and growth process in the formation of nanoparticles can determine the size of nanoparticles which is influenced by certain parameters such as the choice of solvents and stabilizer, the precursor to stabilizer ratio, pH during synthesis, and absorbed dose.
    Matched MeSH terms: Particle Size
  19. Huang SL, Yin CY, Yap SY
    J Hazard Mater, 2010 Feb 15;174(1-3):839-42.
    PMID: 19836131 DOI: 10.1016/j.jhazmat.2009.09.129
    In this study, the particle size distribution and concentration of metallic elements of solvent- and water-based paint dust from bulk dust collected from dust-collecting hoppers were determined. The mean particle size diameter over a 12-week sampling period was determined using a particle size analyzer. The metals composition and concentration of the dust were determined via acid digestion technique followed by concentration analysis using inductively coupled plasma. The volume weighted mean particle diameters were found to be 0.941+/-0.016 and 8.185+/-0.201 microm for solvent- and water-based paint dust, respectively. The mean concentrations of metals in solvent-based paint dust were found to be 100+/-20.00 microg/g (arsenic), 1550+/-550.00 microg/g (copper), 15,680+/-11,780.00 microg/g (lead) and 30,460+/-10,580.00 microg/g (zinc) while the mean concentrations of metals in water-based paint dust were found to be 20.65+/-6.11 microg/g (arsenic), 9.14+/-14.65 microg/g (copper), 57.46+/-22.42 microg/g (lead) and 1660+/-1260 microg/g (zinc). Both paint dust types could be considered as hazardous since almost all of the dust particles were smaller than 10 microm. Particular emphasis on containment of solvent-based paint dust particles should be given since it was shown that they were very fine in size (<1 microm) and had high lead and zinc concentrations.
    Matched MeSH terms: Particle Size
  20. Chuin HC, Che Husna Azhari, Mohamed Aboras, Masfueh Razali, Andanastuti Muchtar
    Sains Malaysiana, 2018;47:1591-1597.
    This study aimed to improve the colloidal stability of yttria-stabilized tetragonal zirconia polycrystalline (Y-TZP)
    suspension through colloidal processing to obtain highly translucent Y-TZP. Agglomeration is often the main complication
    in the processing of nanosized Y-TZP as it deteriorates mechanical and optical properties. Thus, colloidal processing
    is necessary to mitigate the agglomeration in Y-TZP. The colloidal stability of Y-TZP suspension plays a key role for the
    success of colloidal processing. In this study, colloidal processing was conducted at several stages, namely, dispersant
    addition, pH adjustment and sedimentation. Changes in particle size and zeta potential at various stages were recorded.
    The suspensions were then slip-casted to form green bodies. Green bodies were sintered and characterized for density
    and translucency. The results showed that dispersant addition followed by pH adjustment effectively dispersed soft
    agglomerates by introducing electrosteric stabilization, whereas sedimentation successfully segregated hard agglomerates
    and contributed excellent colloidal stability. With high colloidal stability, the translucency of Y-TZP was improved by
    approximately 30%. This study demonstrated different colloidal processing stages and proved that high colloidal stability
    and fine particle size are vital to produce highly translucent Y-TZP.
    Matched MeSH terms: Particle Size
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