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  1. Fulltext Palm-based diacylglycerol fat dry fractionation: effect of crystallisation temperature, cooling rate and agitation speed on physical and chemical properties of fractions
    Ab Latip R, Lee YY, Tang TK, Phuah ET, Lee CM, Tan CP, et al.
    PeerJ, 2013;1:e72.
    PMID: 23682348 DOI: 10.7717/peerj.72
    Fractionation which separates the olein (liquid) and stearin (solid) fractions of oil is used to modify the physicochemical properties of fats in order to extend its applications. Studies showed that the properties of fractionated end products can be affected by fractionation processing conditions. In the present study, dry fractionation of palm-based diacylglycerol (PDAG) was performed at different: cooling rates (0.05, 0.5, 1.0, 1.5, 2.0, 2.5 and 3.0°C/min), end-crystallisation temperatures (30, 35, 40, 45 and 50°C) and agitation speeds (30, 50, 70, 90 and 110 rpm) to determine the effect of these parameters on the properties and yield of the solid and liquid portions. To determine the physicochemical properties of olein and stearin fraction: Iodine value (IV), fatty acid composition (FAC), acylglycerol composition, slip melting point (SMP), solid fat content (SFC), thermal behaviour tests were carried out. Fractionation of PDAG fat changes the chemical composition of liquid and solid fractions. In terms of FAC, the major fatty acid in olein and stearin fractions were oleic (C18:1) and palmitic (C16:0) respectively. Acylglycerol composition showed that olein and stearin fractions is concentrated with TAG and DAG respectively. Crystallization temperature, cooling rate and agitation speed does not affect the IV, SFC, melting and cooling properties of the stearin fraction. The stearin fraction was only affected by cooling rate which changes its SMP. On the other hand, olein fraction was affected by crystallization temperature and cooling rate but not agitation speed which caused changes in IV, SMP, SFC, melting and crystallization behavior. Increase in both the crystallization temperature and cooling rate caused a reduction of IV, increment of the SFC, SMP, melting and crystallization behaviour of olein fraction and vice versa. The fractionated stearin part melted above 65°C while the olein melted at 40°C. SMP in olein fraction also reduced to a range of 26 to 44°C while SMP of stearin fractions increased to (60-62°C) compared to PDAG.
    Matched MeSH terms: Crystallization
  2. Fulltext Preparation, Characterization, Morphological and Particle Properties of Crystallized Palm-Based Methyl Ester Sulphonates (MES) Powder
    Abd Maurad Z, Abdullah LC, Anuar MS, Abdul Karim Shah NN, Idris Z
    Molecules, 2020 Jun 05;25(11).
    PMID: 32516971 DOI: 10.3390/molecules25112629
    Methyl ester sulphonates (MES) have been considered as an alternative green surfactant for the detergent market. Investigation on the purification of methyl ester sulphonates (MES) with various carbon chains of C12, C14, C16 and C16-18 derived from palm methyl ester is of great interest. These MES powders have been repeatedly crystallized with ethanol and the purity of MES has increased to a maximum of 99% active content and 96% crystallinity index without changing the structure. These crystallized MES with high active content have 1.0% to 2.3% moisture content and retained its di-salt content in the range of 5%. The crystallized MES C16 and C16-18 attained excellent flow characteristics. Morphology, structural and its crystallinity analyses showed that the crystals MES had good solubility properties, stable crystal structure (β polymorphic) and triclinic lateral structure when it is in high active content. The brittleness of MES crystals increased from a β' to a β subcell. Crystal with high brittleness has the potential to ease production of powder, which leads to a reduction in the cost of production and improves efficiency.
    Matched MeSH terms: Crystallization
  3. A comparative analysis of microgravity and earth grown thermostable T1 lipase crystals using HDPCG apparatus
    Abd Rahman RN, Ali MS, Sugiyama S, Leow AT, Inoue T, Basri M, et al.
    Protein Pept Lett, 2015;22(2):173-9.
    PMID: 25329331
    Geobacillus zalihae sp. nov., which produces a putative thermostable lipase, represents a novel species, with type strain T1. The characterisation of this intrinsically thermostable T1 lipase either physicochemically or structurally is an important task. The crystallisation of T1lipase in space was carried out using a High-Density Protein Crystal Growth (HDPCG) apparatus with the vapour diffusion method, and X-ray diffraction data were collected. The microgravity environment has improved the size and quality of the crystals as compared to earth grown crystal. The effect of microgravity on the crystallisation of T1 lipase was clearly evidenced by the finer atomic details at 1.35 A resolution. Better electron densities were observed overall compared with the Earth-grown crystals, and comparison shows the subtle but distinct conformations around Na(+) ion binding site stabilized via cation-π interactions. This approach could be useful for solving structure and function of lipases towards exploiting its potentials to various industrial applications.
    Matched MeSH terms: Crystallization
  4. New bioactive glass-ceramic: synthesis and application in PMMA bone cement composites
    Abd Samad H, Jaafar M, Othman R, Kawashita M, Abdul Razak NH
    Biomed Mater Eng, 2011;21(4):247-58.
    PMID: 22182792 DOI: 10.3233/BME-2011-0673
    In present study, a new composition of glass-ceramic was synthesized based on the Na2O-CaO-SiO2-P2O5 glass system. Heat treatment of glass powder was carried out in 2 stages: 600 °C as the nucleation temperature and different temperature on crystallization at 850, 950 and 1000 °C. The glass-ceramic heat-treated at 950 °C was selected as bioactive filler in commercial PMMA bone cement; (PALACOS® LV) due to its ability to form 2 high crystallization phases in comparison with 850 and 1000 °C. The results of this newly glass-ceramic filled PMMA bone cement at 0-16 wt% of filler loading were compared with those of hydroxyapatite (HA). The effect of different filler loading on the setting properties was evaluated. The peak temperature during the polymerization of bone cement decreased when the liquid to powder (L/P) ratio was reduced. The setting time, however, did not show any trend when filler loading was increased. In contrast, dough time was observed to decrease with increased filler loading. Apatite morphology was observed on the surface of the glass-ceramic and selected cement after bioactivity test.
    Matched MeSH terms: Crystallization
  5. Fulltext Crystallization of Electrodeposited Germanium Thin Film on Silicon (100)
    Abidin MSZ, Matsumura R, Anisuzzaman M, Park JH, Muta S, Mahmood MR, et al.
    Materials (Basel), 2013 Nov 06;6(11):5047-5057.
    PMID: 28788375 DOI: 10.3390/ma6115047
    We report the crystallization of electrodeposited germanium (Ge) thin films on n-silicon (Si) (100) by rapid melting process. The electrodeposition was carried out in germanium (IV) chloride: propylene glycol (GeCl₄:C₃H₈O₂) electrolyte with constant current of 50 mA for 30 min. The measured Raman spectra and electron backscattering diffraction (EBSD) images show that the as-deposited Ge thin film was amorphous. The crystallization of deposited Ge was achieved by rapid thermal annealing (RTA) at 980 °C for 1 s. The EBSD images confirm that the orientations of the annealed Ge are similar to that of the Si substrate. The highly intense peak of Raman spectra at 300 cm(-1) corresponding to Ge-Ge vibration mode was observed, indicating good crystal quality of Ge. An additional sub peak near to 390 cm(-1) corresponding to the Si-Ge vibration mode was also observed, indicating the Ge-Si mixing at Ge/Si interface. Auger electron spectroscopy (AES) reveals that the intermixing depth was around 60 nm. The calculated Si fraction from Raman spectra was found to be in good agreement with the value estimated from Ge-Si equilibrium phase diagram. The proposed technique is expected to be an effective way to crystallize Ge films for various device applications as well as to create strain at the Ge-Si interface for enhancement of mobility.
    Matched MeSH terms: Crystallization
  6. Synthesis and characterization of polymeric V2O5/AlO(OH) with nanopores on alumina support
    Ahmad AL, Abd Shukor SR, Leo CP
    J Nanosci Nanotechnol, 2006 Dec;6(12):3910-4.
    PMID: 17256351
    Polymeric vanadium pentoxide gel was formed via the reaction of V2O5 powder with hydrogen peroxide. The polymeric vanadium pentoxide gel was then dispersed in alumina gel. Different vanadium loading composites were coated on alumina support and calcined at 500 degrees C for 1 hr. These composite layers were characterized using TGA, FT-IR, XRD, SEM, and Autosorb. It was found that the lamellar structure of polymerized vanadium pentoxide was retained in the inorganic matrix. Crystalline alumina in gamma phase was formed after calcinations. However, the vanadium-alumina mixed oxides are lack of the well defined PXRD peaks for polycrystalline V2O5. This is possibly because the vanadia species are highly dispersed in the alumina matrix or the vanadia species are dispersed as crystalline which is smaller than 4 nm. In addition, the imbedded polymeric vanadium oxide improved the specific area and average pore diameter of the composite layer.
    Matched MeSH terms: Crystallization/methods*
  7. Fulltext Crystal structure of benzyl-tri-phenyl-phospho-nium chloride monohydrate
    Ahmad J, Abdul Halim SN, How FN
    Acta Crystallogr E Crystallogr Commun, 2015 Jun 1;71(Pt 6):o410-1.
    PMID: 26090195 DOI: 10.1107/S2056989015009159
    The title compound, Ph3(PhCH2)P(+)·Cl(-)·H2O, was obtained unintentionally as the product of an attempted synthesis of a silver di-thio-carbamate complex using benzyl-tri-phenyl-phospho-nium as the counter-ion. The asymmetric unit consists of a phospho-nium cation and a chloride anion, and a water mol-ecule of crystallization. In the crystal, the chloride ion is linked to the water mol-ecule by an O-H⋯Cl hydrogen bond. The three units are further linked via C-H⋯Cl and C-H⋯O hydrogen bonds and C-H⋯ π inter-actions, forming a three-dimensional structure.
    Matched MeSH terms: Crystallization
  8. Fulltext Fragment-based in silico design of SARS-CoV-2 main protease inhibitors
    Ahmad S, Usman Mirza M, Yean Kee L, Nazir M, Abdul Rahman N, Trant JF, et al.
    Chem Biol Drug Des, 2021 Oct;98(4):604-619.
    PMID: 34148292 DOI: 10.1111/cbdd.13914
    3CLpro is essential for SARS-CoV-2 replication and infection; its inhibition using small molecules is a potential therapeutic strategy. In this study, a comprehensive crystallography-guided fragment-based drug discovery approach was employed to design new inhibitors for SARS-CoV-2 3CLpro. All small molecules co-crystallized with SARS-CoV-2 3CLpro with structures deposited in the Protein Data Bank were used as inputs. Fragments sitting in the binding pocket (87) were grouped into eight geographical types. They were interactively coupled using various synthetically reasonable linkers to generate larger molecules with divalent binding modes taking advantage of two different fragments' interactions. In total, 1,251 compounds were proposed, and 7,158 stereoisomers were screened using Glide (standard precision and extra precision), AutoDock Vina, and Prime MMGBSA. The top 22 hits having conformations approaching the linear combination of their constituent fragments were selected for MD simulation on Desmond. MD simulation suggested 15 of these did adopt conformations very close to their constituent pieces with far higher binding affinity than either constituent domain alone. These structures could provide a starting point for the further design of SARS-CoV-2 3CLpro inhibitors with improved binding, and structures are provided.
    Matched MeSH terms: Crystallization
  9. Fulltext Experimental and molecular modeling approach to optimize suitable polymers for fabrication of stable fluticasone nanoparticles with enhanced dissolution and antimicrobial activity
    Ahmed S, Govender T, Khan I, Rehman NU, Ali W, Shah SMH, et al.
    Drug Des Devel Ther, 2018;12:255-269.
    PMID: 29440875 DOI: 10.2147/DDDT.S148912
    Background and aim: The challenges with current antimicrobial drug therapy and resistance remain a significant global health threat. Nanodrug delivery systems are playing a crucial role in overcoming these challenges and open new avenues for effective antimicrobial therapy. While fluticasone (FLU), a poorly water-soluble corticosteroid, has been reported to have potential antimicrobial activity, approaches to optimize its dissolution profile and antimicrobial activity are lacking in the literature. This study aimed to combine an experimental study with molecular modeling to design stable FLU nanopolymeric particles with enhanced dissolution rates and antimicrobial activity.

    Methods: Six different polymers were used to prepare FLU nanopolymeric particles: hydroxyl propyl methylcellulose (HPMC), poly (vinylpyrrolidone) (PVP), poly (vinyl alcohol) (PVA), ethyl cellulose (EC), Eudragit (EUD), and Pluronics®. A low-energy method, nanoprecipitation, was used to prepare the polymeric nanoparticles.

    Results and conclusion: The combination of HPMC-PVP and EUD-PVP was found most effective to produce stable FLU nanoparticles, with particle sizes of 250 nm ±2.0 and 280 nm ±4.2 and polydispersity indices of 0.15 nm ±0.01 and 0.25 nm ±0.03, respectively. The molecular modeling studies endorsed the same results, showing highest polymer drug binding free energies for HPMC-PVP-FLU (-35.22 kcal/mol ±0.79) and EUD-PVP-FLU (-25.17 kcal/mol ±1.12). In addition, it was observed that Ethocel® favored a wrapping mechanism around the drug molecules rather than a linear conformation that was witnessed for other individual polymers. The stability studies conducted for 90 days demonstrated that HPMC-PVP-FLU nanoparticles stored at 2°C-8°C and 25°C were more stable. Crystallinity of the processed FLU nanoparticles was confirmed using differential scanning calorimetry, powder X-ray diffraction analysis and TEM. The Fourier transform infrared spectroscopy (FTIR) studies showed that there was no chemical interaction between the drug and chosen polymer system. The HPMC-PVP-FLU nanoparticles also showed enhanced dissolution rate (P<0.05) compared to the unprocessed counterpart. The in vitro antibacterial studies showed that HPMC-PVP-FLU nanoparticles displayed superior effect against gram-positive bacteria compared to the unprocessed FLU and positive control.

    Matched MeSH terms: Crystallization
  10. Parameters affecting the photocatalytic degradation of dyes using TiO2-based photocatalysts: a review
    Akpan UG, Hameed BH
    J Hazard Mater, 2009 Oct 30;170(2-3):520-9.
    PMID: 19505759 DOI: 10.1016/j.jhazmat.2009.05.039
    This paper presents the review of the effects of operating parameters on the photocatalytic degradation of textile dyes using TiO2-based photocatalysts. It further examines various methods used in the preparations of the considered photocatalysts. The findings revealed that various parameters, such as the initial pH of the solution to be degraded, oxidizing agents, temperature at which the catalysts must be calcined, dopant(s) content and catalyst loading exert their individual influence on the photocatalytic degradation of any dye in wastewaters. It was also found out that sol-gel method is widely used in the production of TiO2-based photocatalysts because of the advantage derived from its ability to synthesize nanosized crystallized powder of the photocatalysts of high purity at relatively low temperature.
    Matched MeSH terms: Crystallization
  11. Fulltext The Impact of Polyvinylpyrrolidone on Properties of Cadmium Oxide Semiconductor Nanoparticles Manufactured by Heat Treatment Technique
    Al-Hada NM, Saion E, Talib ZA, Shaari AH
    Polymers (Basel), 2016 Apr 08;8(4).
    PMID: 30979222 DOI: 10.3390/polym8040113
    Cadmium oxide semiconductor nanoparticles were produced using a water based mixture, incorporating cadmium nitrates, polyvinyl pyrrolidone (PVP), and calcination temperature. An X-ray diffraction (XRD) evaluation was conducted to determine the degree of crystallization of the semiconductor nanoparticles. In addition, scanning electron microscopy (SEM) was conducted to identify the morphological features of the nanoparticles. The typical particle sizes and particle dispersal were analyzed via the use of transmission electron microscopy (TEM). The findings provided further support for the XRD outcomes. To determine the composition phase, Fourier transform infrared spectroscopy (FT-IR) was conducted, as it indicated the existence of not only metal oxide ionic band in the selection of samples, but also the efficient removal of organic compounds following calcinations. The optical characteristics were demonstrated, so as to analyze the energy band gap via the use of a UV⁻Vis spectrophotometer. A reduced particle size resulted in diminution of the intensity of photoluminescence, was demonstrated by PL spectra. Plus, the magnetic characteristics were examined using an electron spin resonance (ESR) spectroscopy, which affirmed the existence of unpaired electrons.
    Matched MeSH terms: Crystallization
  12. Fulltext Polypropylene/Graphene Nanocomposites: Effects of GNP Loading and Compatibilizers on the Mechanical and Thermal Properties
    Al-Saleh MA, Yussuf AA, Al-Enezi S, Kazemi R, Wahit MU, Al-Shammari T, et al.
    Materials (Basel), 2019 Nov 27;12(23).
    PMID: 31783544 DOI: 10.3390/ma12233924
    In this research work, graphene nanoplatelets (GNP) were selected as alternative reinforcing nanofillers to enhance the properties of polypropylene (PP) using different compatibilizers called polypropylene grafted maleic anhydride (PP-g-MA) and ethylene-octene elastomer grafted maleic anhydride (POE-g-MA). A twin screw extruder was used to compound PP, GNP, and either the PP-g-MA or POE-g-MA compatibilizer. The effect of GNP loading on mechanical and thermal properties of neat PP was investigated. Furthermore, the influence and performance of different compatibilizers on the final properties, such as mechanical and thermal, were discussed and reported. Tensile, flexural, impact, melting temperature, crystallization temperature, and thermal stability were evaluated by using a universal testing system, differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). For mechanical properties, it was found that increasing GNP content from 1 wt.% to 5 wt.% increased tensile strength of the neat PP up to 4 MPa. The influence of compatibilizers on the mechanical properties had been discussed and reported. For instance, the addition of PP-g-MA compatibilizer improved tensile strength of neat PP with GNP loading. However, the addition of compatibilizer POE-g-MA slightly decreased the tensile strength of neat PP. A similar trend of behavior was observed for flexural strength. For thermal properties, it was found that both GNP loading and compatibilizers have no significant influence on both crystallization and melting temperature of neat PP. For thermal stability, however, it was found that increasing the GNP loading had a significant influence on improving the thermal behavior of neat PP. Furthermore, the addition of compatibilizers into the PP/GNP nanocomposite had slightly improved the thermal stability of neat PP.
    Matched MeSH terms: Crystallization
  13. Fulltext Capillary-seeding crystallization and preliminary crystallographic analysis of a solvent-tolerant elastase from Pseudomonas aeruginosa strain K
    Ali MS, Said ZS, Rahman RN, Chor AL, Basri M, Salleh AB
    Int J Mol Sci, 2013 Aug 28;14(9):17608-17.
    PMID: 23989606 DOI: 10.3390/ijms140917608
    Seeding is a versatile method for optimizing crystal growth. Coupling this technique with capillary counter diffusion crystallization enhances the size and diffraction quality of the crystals. In this article, crystals for organic solvent-tolerant recombinant elastase strain K were successfully produced through microseeding with capillary counter-diffusion crystallization. This technique improved the nucleation success rate with a low protein concentration (3.00 mg/mL). The crystal was grown in 1 M ammonium phosphate monobasic and 0.1 M sodium citrate tribasic dihydrate pH 5.6. The optimized crystal size was 1 × 0.1 × 0.05 mm³. Elastase strain K successfully diffracted up to 1.39 Å at SPring-8, Japan, using synchrotron radiation for preliminary data diffraction analysis. The space group was determined to be monoclinic space group P12(1)1 with unit cell parameters of a = 38.99 Ǻ, b = 90.173 Å and c = 40.60 Å.
    Matched MeSH terms: Crystallization/methods*
  14. Fulltext A simple route to vertical array of quasi-1D ZnO nanofilms on FTO surfaces: 1D-crystal growth of nanoseeds under ammonia-assisted hydrolysis process
    Ali Umar A, Abd Rahman MY, Taslim R, Mat Salleh M, Oyama M
    Nanoscale Res Lett, 2011 Oct 25;6:564.
    PMID: 22027275 DOI: 10.1186/1556-276X-6-564
    A simple method for the synthesis of ZnO nanofilms composed of vertical array of quasi-1D ZnO nanostructures (quasi-NRs) on the surface was demonstrated via a 1D crystal growth of the attached nanoseeds under a rapid hydrolysis process of zinc salts in the presence of ammonia at room temperature. In a typical procedure, by simply controlling the concentration of zinc acetate and ammonia in the reaction, a high density of vertically oriented nanorod-like morphology could be successfully obtained in a relatively short growth period (approximately 4 to 5 min) and at a room-temperature process. The average diameter and the length of the nanostructures are approximately 30 and 110 nm, respectively. The as-prepared quasi-NRs products were pure ZnO phase in nature without the presence of any zinc complexes as confirmed by the XRD characterisation. Room-temperature optical absorption spectroscopy exhibits the presence of two separate excitonic characters inferring that the as-prepared ZnO quasi-NRs are high-crystallinity properties in nature. The mechanism of growth for the ZnO quasi-NRs will be proposed. Due to their simplicity, the method should become a potential alternative for a rapid and cost-effective preparation of high-quality ZnO quasi-NRs nanofilms for use in photovoltaic or photocatalytics applications.PACS: 81.07.Bc; 81.16.-c; 81.07.Gf.
    Matched MeSH terms: Crystallization
  15. Microwave modified non-crosslinked pectin films with modulated drug release
    Anuar NK, Wong TW, Taib MN
    Pharm Dev Technol, 2012 Jan-Feb;17(1):110-7.
    PMID: 20958167 DOI: 10.3109/10837450.2010.522584
    The effects of microwave on drug release properties of pectin films carrying sulfanilamide (SN-P), sulfathiazole (ST-P) and sulfamerazine (SM-P) of high to low aqueous solubilities were investigated. These films were prepared by solvent evaporation technique and treated by microwave at 80 W for 5-40 min. Their profiles of drug dissolution, drug content, matrix interaction and matrix crystallinity were determined by drug dissolution testing, drug content assay, differential scanning calorimetry, X-ray diffractometry and scanning electron microscopy techniques. Microwave induced an increase in matrix amorphousness but lower drug release propensity with a greater retardation extent in SN-P films, following a rise in strength of matrix interaction. A gain in amorphous structure does not necessarily increase the drug release of film. Microwave can possibly retard drug release of pectin film carrying water-soluble drug through modulating its state of matrix interaction.
    Matched MeSH terms: Crystallization
  16. Co-crystallization of a neutral mol-ecule and its zwitterionic tautomer: structure and Hirshfeld surface analysis of 5-methyl-4-(5-methyl-1H-pyrazol-3-yl)-2-phenyl-2,3-di-hydro-1H-pyrazol-3-one 5-methyl-4-(5-methyl-1H-pyrazol-2-ium-3-yl)-3-oxo-2-phenyl-2,3-di-hydro-1H-pyrazol-1-ide monohydrate
    Asiri AM, Alzahrani KAH, Faidallah HM, Alamry KA, Jotani MM, Tiekink ERT
    Acta Crystallogr E Crystallogr Commun, 2019 May 01;75(Pt 5):565-570.
    PMID: 31110787 DOI: 10.1107/S2056989019004389
    The title compound, 2C14H14N4O·H2O, comprises a neutral mol-ecule containing a central pyrazol-3-one ring flanked by an N-bound phenyl group and a C-bound 5-methyl-1H-pyrazol-3-yl group (at positions adjacent to the carbonyl substituent), its zwitterionic tautomer, whereby the N-bound proton of the central ring is now resident on the pendant ring, and a water mol-ecule of crystallization. Besides systematic variations in geometric parameters, the two independent organic mol-ecules have broadly similar conformations, as seen in the dihedral angle between the five-membered rings [9.72 (9)° for the neutral mol-ecule and 3.32 (9)° for the zwitterionic tautomer] and in the dihedral angles between the central and pendant five-membered rings [28.19 (8) and 20.96 (8)° (neutral mol-ecule); 11.33 (9) and 11.81 (9)°]. In the crystal, pyrazolyl-N-H⋯O(carbon-yl) and pyrazolium-N-H⋯N(pyrazol-yl) hydrogen bonds between the independent organic mol-ecules give rise to non-symmetric nine-membered {⋯HNNH⋯NC3O} and {⋯HNN⋯HNC3O} synthons, which differ in the positions of the N-bound H atoms. These aggregates are connected into a supra-molecular layer in the bc plane by water-O-H⋯N(pyrazolide), water-O-H⋯O(carbon-yl) and pyrazolyl-N-H⋯O(water) hydrogen bonding. The layers are linked into a three-dimensional architecture by methyl-C-H⋯π(phen-yl) inter-actions. The different inter-actions, in particular the weaker contacts, formed by the organic mol-ecules are clearly evident in the calculated Hirshfeld surfaces, and the calculated electrostatic potentials differentiate the tautomers.
    Matched MeSH terms: Crystallization
  17. Fulltext The Study of Electrical and Electrochemical Properties of Magnesium Ion Conducting CS: PVA Based Polymer Blend Electrolytes: Role of Lattice Energy of Magnesium Salts on EDLC Performance
    Aziz SB, Brza MA, Hamsan EMADMH, Hadi JM, Kadir MFZ, Abdulwahid RT
    Molecules, 2020 Oct 01;25(19).
    PMID: 33019618 DOI: 10.3390/molecules25194503
    Plasticized magnesium ion conducting polymer blend electrolytes based on chitosan (CS): polyvinyl alcohol (PVA) was synthesized with a casting technique. The source of ions is magnesium triflate Mg(CF3SO3)2, and glycerol was used as a plasticizer. The electrical and electrochemical characteristics were examined. The outcome from X-ray diffraction (XRD) examination illustrates that the electrolyte with highest conductivity exhibits the minimum degree of crystallinity. The study of the dielectric relaxation has shown that the peak appearance obeys the non-Debye type of relaxation process. An enhancement in conductivity of ions of the electrolyte system was achieved by insertion of glycerol. The total conductivity is essentially ascribed to ions instead of electrons. The maximum DC ionic conductivity was measured to be 1.016 × 10-5 S cm-1 when 42 wt.% of plasticizer was added. Potential stability of the highest conducting electrolyte was found to be 2.4 V. The cyclic voltammetry (CV) response shows the behavior of the capacitor is non-Faradaic where no redox peaks appear. The shape of the CV response and EDLC specific capacitance are influenced by the scan rate. The specific capacitance values were 7.41 F/g and 32.69 F/g at 100 mV/s and 10 mV/s, respectively. Finally, the electrolyte with maximum conductivity value is obtained and used as electrodes separator in the electrochemical double-layer capacitor (EDLC) applications. The role of lattice energy of magnesium salts in energy storage performance is discussed in detail.
    Matched MeSH terms: Crystallization
  18. Effect of Al and N doping on structural and optical properties of sol-gel derived ZnO thin films
    Bangbai C, Techitdheera W, Chongsri K, Pecharapa W
    Sains Malaysiana, 2013;42:239-246.
    In this work, the preparation of ZnO, N-doped ZnO (NZO), Al-doped ZnO (AZO) and Al, N-doped ZnO (ANZO) thin films by the sol-gel spin-coating method is reported. The structural properties and surface morphologies of films were characterized by X-ray diffraction (XRD) and field emission scanning electron microscope (FE-SEM). The optical properties of the films were interpreted from their transmission spectra using UV-VIS spectrophotometer. The XRD and SEM results disclosed that the crystallization quality and grain size of as-prepared films were highly influenced by N and Al doping. UV-VIS spectrophotometer results indicated that Al and N additives could significantly enhance the optical transparency and induce the blue-shift in optical bandgap of ZnO films.
    Matched MeSH terms: Crystallization
  19. Fulltext Rietveld quantitative phase analysis of non-stoichiometric cordierite synthesised from mainly talc and kaolin: effect of sintering temperature
    Banjuraizah Johar, Hasmaliza Mohamad, Zainal Arifin Ahmad
    Journal of Nuclear and Related Technologies, 2009;2009(1):103-110.
    MyJurnal
    Indialite or α-cordierite was synthesized by glass crystallization method using mainly talc and kaolin and with small amount of MgO, Al2O3, SiO2 to compensate the chemical formulation of non-stoihiometric compositions of cordierite. (3MgO.1.5Al2O3.5SiO2). B2O3, P2O5 and CaO was also added to decrease the melting and sintering temperature of cordierite. The glasses were pelletized and sintered from 850 o C up to 1050 o C. Phase compositions of both heat treated glass was quantified by X-ray powder diffraction data by the Rietveld method using TOPAS Ver 3 software. Result shows that about 60wt% of α cordierite has successfully crystallized at 850 o C. Beside secondary phases (forsterite) which come from initial raw materials, phases from grinding media were also presents in the sample. The contamination was considered high since it has reacted with existence phases to form a new phase at higher temperature. Without any contamination from grinding it was expected to obtain more than 90wt% α cordierite using the same composition.
    Matched MeSH terms: Crystallization
  20. Fabrication and deformation behaviour of multilayer Al2O3/Ti/TiO2 nanotube arrays
    Baradaran S, Basirun WJ, Zalnezhad E, Hamdi M, Sarhan AA, Alias Y
    J Mech Behav Biomed Mater, 2013 Apr;20:272-82.
    PMID: 23453827 DOI: 10.1016/j.jmbbm.2013.01.020
    In this study, titanium thin films were deposited on alumina substrates by radio frequency (RF) magnetron sputtering. The mechanical properties of the Ti coatings were evaluated in terms of adhesion strength at various RF powers, temperatures, and substrate bias voltages. The coating conditions of 400W of RF power, 250°C, and a 75V substrate bias voltage produced the strongest coating adhesion, as obtained by the Taguchi optimisation method. TiO2 nanotube arrays were grown as a second layer on the Ti substrates using electrochemical anodisation at a constant potential of 20V and anodisation times of 15min, 45min, and 75min in a NH4F electrolyte solution (75 ethylene glycol: 25 water). The anodised titanium was annealed at 450°C and 650°C in a N2 gas furnace to obtain different phases of titania, anatase and rutile, respectively. The mechanical properties of the anodised layer were investigated by nanoindentation. The results indicate that Young's modulus and hardness increased with annealing temperature to 650°C.
    Matched MeSH terms: Crystallization/methods
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