Displaying publications 141 - 160 of 428 in total

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  1. Fulltext Microstructure analysis, physical and thermal properties of al2o3-al2tio5 functionally graded ceramics for the application of car brake rot
    Oo, Z., Sujan, D., Rong Kimberly, F. P
    Pertanika Journal of Science & Technology, 2015;23(1):153-161.
    MyJurnal
    Aluminium titanate (AT) (Al2TiO5) is a promising engineering material because of its low thermal expansion coefficient, excellent thermal shock resistance, good refractoriness and non-wetting with most metals. Functionally graded material (FGM) is generally a particulate composite with continuously varying volume fractions. FGMs are alternative materials for dental implants, building materials and ballistic protection. It has been of great interest to future engines, internal combustion engines, metal cutting and other high temperature engineering application. There has been a demand for an adequate disc brake that requires less maintenance in the automotive manufacturing industry. FGM, the next evolution of layered structure, consists of graded compositions that are dispersed across the ceramic which produces a gradual improvement in the properties across the ceramic at a steady pace.
    Matched MeSH terms: Aluminum
  2. Fulltext Natural Convection Flow of a Nanofluid in an Inclined Square Enclosure Partially Filled with a Porous Medium
    Alsabery AI, Chamkha AJ, Saleh H, Hashim I
    Sci Rep, 2017 05 24;7(1):2357.
    PMID: 28539585 DOI: 10.1038/s41598-017-02241-x
    This work analyses free convection flow of a nanofluid in an inclined square enclosure consisting of a porous layer and a nanofluid layer using the finite difference methodology. Sinusoidal temperature boundary conditions are imposed on the two opposing vertical walls. Nanofluids with water as base and Ag or Cu or Al2O3 or TiO2 nanoparticles are considered for the problem. The related parameters of this study are the Darcy number, nanoparticle volume fraction, phase deviation, amplitude ratio, porous layer thickness and the inclination angle of the cavity. A comparison with previously published work is performed and the results are in good agreement. Detailed numerical data for the fluid flow and thermal distributions inside the square enclosure, and the Nusselt numbers are presented. The obtained results show that the heat transfer is considerably affected by the porous layer increment. Several nanoparticles depicted a diversity improvement on the convection heat transfer.
    Matched MeSH terms: Aluminum Oxide
  3. Fulltext Assessments of Process Parameters on Cutting Force and Surface Roughness during Drilling of AA7075/TiB2 In Situ Composite
    Parasuraman S, Elamvazuthi I, Kanagaraj G, Natarajan E, Pugazhenthi A
    Materials (Basel), 2021 Mar 31;14(7).
    PMID: 33807476 DOI: 10.3390/ma14071726
    Reinforced aluminum composites are the basic class of materials for aviation and transport industries. The machinability of these composites is still an issue due to the presence of hard fillers. The current research is aimed to investigate the drilling topographies of AA7075/TiB2 composites. The samples were prepared with 0, 3, 6, 9 and 12 wt.% of fillers and experiments were conducted by varying the cutting speed, feed, depth of cut and tool nose radius. The machining forces and surface topographies, the structure of the cutting tool and chip patterns were examined. The maximum cutting force was recorded upon increase in cutting speed because of thermal softening, loss of strength discontinuity and reduction of the built-up-edge. The increased plastic deformation with higher cutting speed resulted in the excess metal chip. In addition, the increase in cutting speed improved the surface roughness due to decrease in material movement. The cutting force was decreased upon high loading of TiB2 due to the deterioration of chips caused by fillers. Further introduction of TiB2 particles above 12 wt.% weakened the composite; however, due to the impact of the microcutting action of the fillers, the surface roughness was improved.
    Matched MeSH terms: Aluminum
  4. Fulltext Strain-Reduced Micro-LEDs Grown Directly Using Partitioned Growth
    Lu S, Zhang Y, Zhang ZH, Tsai PC, Zhang X, Tan ST, et al.
    Front Chem, 2021;9:639023.
    PMID: 33816438 DOI: 10.3389/fchem.2021.639023
    Strain-reduced micro-LEDs in 50 μm × 50 μm, 100 μm × 100 μm, 200 μm × 200 μm, 500 μm × 500 μm, and 1,000 μm × 1,000 μm sizes were grown on a patterned c-plane sapphire substrate using partitioned growth with the metal-organic chemical-vapor deposition (MOCVD) technique. The size effect on the optical properties and the indium concentration for the quantum wells were studied experimentally. Here, we revealed that the optical properties can be improved by decreasing the chip size (from 1,000 to 100 µm), which can correspondingly reduce the in-plane compressive stress. However, when the chip size is further reduced to 50 μm × 50 μm, the benefit of strain release is overridden by additional defects induced by the higher indium incorporation in the quantum wells and the efficiency of the device decreases. The underlying mechanisms of the changing output power are uncovered based on different methods of characterization. This work shows the rules of thumb to achieve optimal power performance for strain-reduced micro-LEDs through the proposed partitioned growth process.
    Matched MeSH terms: Aluminum Oxide
  5. Fulltext Surface marker-assisted for orbital navigation surgery: a dry skull study
    Nazimi, A.J., Nuraudi Zafirah, A.R., Nur Syaira, I., Izhar, A.A., Muhd Fazlynizam, R.
    Medicine & Health, 2020;15(1):237-249.
    MyJurnal
    Tujuan kajian ini adalah untuk menerokai kaedah pembantu penanda permukaan terhadap implan orbital untuk pembedahan tulang orbit. Enam tengkorak manusia dewasa kering telah digunakan dalam kajian ini. Implan orbital aluminium yang disediakan secara individu, dengan ketebalan 0.4 mm disediakan untuk lantai orbit secara bilateral. Empat penanda permukaan implan fizikal dari aspek anterior dan posterior implan yang disediakan dan diimbas secara optik. Pemeriksaan pra-pembedahan tomografi berkomputer ‘cone-beam’ (CBCT) diperolehi untuk semua lantai orbit. Data 'Digital Imaging and Communications in Medicine' (DICOM) tengkorak diambil, diimport dan direka bentuk dengan format data stereolithografi (STL) implan orbital masing-masing menggunakan iPlan CMF (Versi 3.0, BrainLab, Jerman). Teknik gabungan imej dilakukan untuk setiap tengkorak selepas pembinaan semula dengan pengambilan pos-pembedahan CBCT. Pengukuran berasaskan daripada data tomografi terhadap posisi implant kemudian dinilai di antara kedudukan implan yang direncanakan dan yang direalisasikan dalam satah sagittal dan coronal. Analisa statistik dijalankan menggunakan Statistik Statistik PASW® 18. Hasil kajian menunjukkan bahawa 38 daripada 48 penanda permukaan yang dinilai menunjukkan peningkatan ketinggian kedudukan dalam skala kecil pasca-pembedahan berbanding dengan kedudukan implan orbital maya. Semakan metrik Euclidean menunjukkan perbezaan yang kurang daripada 1.00 mm dalam semua penanda permukaan kecuali pada kawasan lej posterior dan anterior dalam penilaian satah sagittal. Kajian ini menunjukkan bahawa penempatan penanda permukaan terhadap implant orbit dalam pembedahan navigasi orbit menyumbang kepada kedudukan implan orbital secara konsisten.
    Matched MeSH terms: Aluminum
  6. Fulltext Early Development of Fig (Ficus carica L.) Root and Shoot Using Different Propagation Medium and Cutting Types
    Shamsuddin MS, Shahari R, Amri CNAC, Tajudin NS, Mispan MR, Salleh MS
    Trop Life Sci Res, 2021 Mar;32(1):83-90.
    PMID: 33936552 DOI: 10.21315/tlsr2021.32.1.5
    This study aimed at determining the effects of propagation medium and cutting types on the early growth performance of fig (Ficus carica L.) root and shoot. The experiment was conducted at the Glasshouse and Nursery Complex (GNC), International Islamic University Malaysia (IIUM). The split-plot design was employed with the main plot (propagation medium) and sub-plot (types of cutting). The propagation medium were sand:topsoil (1:3) (M1), topsoil:peat:sawdust (1:1:1) (M2) and peat:perlite (1:1) (M3). Two types of cutting were semi-hardwood (C1) and hardwood (C2). As a result, there were a significant effect of propagation medium on measured parameters. This study revealed that the most effective propagation medium and cutting types for the propagation of fig were a combination of peat and perlite at 1:1 ratio (M3) and hardwood cutting (C2), respectively as evidenced by significantly higher root and shoot growth quality as compared to other treatments.
    Matched MeSH terms: Aluminum Oxide
  7. Revealing obliterated engraved marks on high strength aluminium alloy (AA7010) surfaces by etching technique
    Bong YU, Kuppuswamy R
    Forensic Sci Int, 2010 Feb 25;195(1-3):86-92.
    PMID: 20022189 DOI: 10.1016/j.forsciint.2009.11.018
    Restoration of obliterated engraved marks on high strength Al-Zn-Mg-Cu alloy (AA7010) surfaces by etching technique was studied. The alloy surfaces were mechanically engraved with some identification marks using "Gravograph". The marks were then erased by removing the metal to different levels up to and below the depth of engraving. Five metallographic reagents were tested on the obliterated surfaces by etching. The following two methods (i) immersion in 10% aq. phosphoric acid and (ii) alternate swabbing of 60% HCl and 40% NaOH were found to be quite effective to reveal the obliterated marks. These two procedures were also able to show effectively the marks obliterated by over-engraving and centre punching. Of the two techniques immersion in phosphoric acid provided more contrast. Interestingly, alternate swabbing of 60% HCl and 40% NaOH presented itself to be the common reagent for restoration on pure aluminium as well as its alloy surfaces. This is evident from our own current experiments and those of earlier researchers [G. Peeler, S. Gutowski, H. Wrobel, G. Dower, The restoration of impressed characters on aluminium alloy motor cycle frames, J. Forensic Ident. 58 (1) (2008) 27-32; M. Izhar M. Baharum, R. Kuppuswamy, A.A. Rahman, Restoration of engraved marks on aluminium surfaces by etching technique, Forensic Sci. Int. 177 (2008) 221-227]. The findings have assumed importance as engines and chassis of cars and frames of firearms are currently made of high strength aluminium alloys and recovery on these surfaces by current methods is not satisfactory.
    Matched MeSH terms: Aluminum
  8. A survey of some metallographic etching reagents for restoration of obliterated engraved marks on aluminium-silicon alloy surfaces
    Uli N, Kuppuswamy R, Amran MF
    Forensic Sci Int, 2011 May 20;208(1-3):66-73.
    PMID: 21145675 DOI: 10.1016/j.forsciint.2010.11.005
    A brief survey to assess the sensitivity and efficacy of some common etching reagents for revealing obliterated engraved marks on Al-Si alloy surfaces is presented. Experimental observations have recommended use of alternate swabbing of 10% NaOH and 10% HNO(3) on the obliterated surfaces for obtaining the desired results. The NaOH etchant responsible for bringing back the original marks resulted in the deposition of some dark coating that has masked the recovered marks. The coating had been well removed by dissolving it in HNO(3) containing 10-20% acid. However, the above etching procedure was not effective on aluminium (99% purity) and Al-Zn-Mg-Cu alloy surfaces. Also the two reagents (i) immersion in 10% aq. phosphoric acid and (ii) alternate swabbing of 60% HCl and 40% NaOH suggested earlier for high strength Al-Zn-Mg-Cu alloys [23] were quite ineffective on Al-Si alloys. Thus different aluminium alloys needed different etching treatments for successfully restoring the obliterated marks. Al-Si alloys used in casting find wide applications especially in the manufacture of engine blocks of motor vehicles. Hence, the results presented in this paper are of much relevance in serial number restoration problems involving this alloy.
    Matched MeSH terms: Aluminum
  9. Incorporation of sewage sludge in clay brick and its characterization
    Liew AG, Idris A, Wong CH, Samad AA, Noor MJ, Baki AM
    Waste Manag Res, 2004 Aug;22(4):226-33.
    PMID: 15462329
    This study reports the use of sewage sludge generated from sewage treatment plant (STP) as raw material in a clay brick-making process. The physico-chemical and mineralogical characterization of the sewage sludge and clay were carried out in order to identify the major technological constraints and to define the sludge pretreatment requirements if necessary. Moreover, the effects on processing conditions and/or on changes of typical final characteristics are also evaluated. Bricks were produced with sewage sludge additions ranging from 10 to 40% by dry weight. The texture and finishing of the surface of sludge-amended clay bricks were rather poor. As for the physical and chemical properties, bricks with a sludge content of up to 40 wt.% were capable of meeting the relevant technical standards. However, bricks with more than 30 wt.% sludge addition are not recommended for use since they are brittle and easily broken even when handled gently. A tendency for a general degradation of brick properties with sludge additions was observed due to its refractory nature. Therefore, sludge bricks of this nature are only suitable for use as common bricks, which are normally not exposed to view, because of poor surface finishing.
    Matched MeSH terms: Aluminum Silicates
  10. Fulltext Aerogel and expanded perlite incorporated lightweight cementitious composites containing crushed glass: Evaluation of the drying shrinkage and alkali-silica expansion
    Shah SN, Tan TH, Tey OW, Leong GW, Chin YS, Yuen CW, et al.
    Sci Prog, 2022;105(2):368504221091186.
    PMID: 35379044 DOI: 10.1177/00368504221091186
    Lightweight cementitious composite (LCC) produced by incorporating lightweight silica aerogel was explored in this study. Silica aerogel was incorporated as 60% replacement of fine aggregate (sand/crushed glass) in producing the LCC. The effect of aerogel on the drying shrinkage and alkali-silica expansion of LCC was evaluated and compared with those of lightweight expanded perlite aggregate. At the density of 1600  ±  100 kg/m3, the aerogel/ expanded perlite LCC had attained compressive strength of about 17/24 MPa and 22/26 MPa in mixtures with sand and crushed glass as a fine aggregate, respectively. The inclusion of aerogel and expanded perlite increased the drying shrinkage. The drying shrinkage of aerogel LCC was up to about 3 times of the control mixtures. Although the presence of aerogel and expanded perlite could reduce the alkali-silica expansion when partially replacing crushed glass, the aerogel-glass LCC still recorded expansion exceeding the maximum limit of 0.10% at 14 days. However, when 15% cement was replaced with fly ash and granulated blast furnace slag, the alkali-silica expansion was reduced to 0.03% and 0.10%, respectively. Microstructural observations also revealed that the aerogel with fly ash can help in reducing the alkali-silica expansion in mixes containing the reactive crushed glass aggregate.
    Matched MeSH terms: Aluminum Oxide
  11. Fulltext Adsorption of DDT and PCB by Nanomaterials from Residual Soil
    Taha MR, Mobasser S
    PLoS One, 2015;10(12):e0144071.
    PMID: 26659225 DOI: 10.1371/journal.pone.0144071
    This paper presents the findings of a study on adsorption of dichlorodiphenythreechloroethen (DDT) and polychlorinated biphenyls (PCBs) on three nanomaterials including Multi walled Carbon Nanotube (MWNT), nano-clay and nano-alumina. DDT and PCBs are of significant concern due their high toxicity and long environmental half-lives. Experiments were conducted using batch adsorption procedures at different DDT and PCBs concentrations, from 10 to 60 mg/L. The amounts of MWNT, nano-clay and Nano-alumina used were 0.25%, 0.50%, 0.75%, 1%, 2% and 10%. The adsorption of PCBs solution onto the MWNT, nano-clay and nano-alumina was characterized by an initial rapid adsorption which eventually became constant within 22, 20, and 17 hours, respectively. The adsorption of DDT solution onto the MWNT, nano-clay and nano-alumina was also characterized by an initial rapid adsorption which gradually became constant within 22, 22 and 16 hours, respectively. Results of this study indicated that MWNT was a better adsorbent material compared to nano-clay and nano-alumina for both contaminants in this study. While at 10% of MWNT 88.9% and 77% of DDT and PCB were removed by MWNT, respectively. The effect of pH and temperature were also investigated.
    Matched MeSH terms: Aluminum Oxide/chemistry; Aluminum Silicates/chemistry
  12. Fulltext Effect of sandblasting, silica coating, and erbium: Yttrium-Aluminum-Garnet laser treatment on the shear bond strength of self-adhesive resin cement to alumina ceramics
    Caglar I, Ates SM, Boztoprak Y, Aslan YU, Duymus ZY
    Niger J Clin Pract, 2018 Aug;21(8):1000-1007.
    PMID: 30074001 DOI: 10.4103/njcp.njcp_300_17
    Objective: The aim of this study was to investigate the different surface treatments on the bond strength of self-adhesive resin cement to high-strength ceramic.

    Materials and Methods: Ninety aluminum oxide ceramic (Turkom-Ceramic Sdn. Bhd., Kuala Lumpur, Malaysia) specimens were produced and divided into nine groups to receive the following surface treatments: control group, no treatment (Group C), sandblasting (Group B), silica coating (Group S), erbium: yttrium-aluminum-garnet (Er:YAG) laser irradiation at 150 mJ 10 Hz (Group L1), Er:YAG laser irradiation at 300 mJ 10 Hz (Group L2), sandblasting + L1 (Group BL1), sandblasting + L2 (Group BL2), silica coating + L1 (Group SL1), and silica coating + L2 (Group SL2). After surface treatments, surface roughness (SR) values were measured and surface topography was evaluated. Resin cement was applied on the specimen surface, and shear bond strength (SBS) tests were performed. Data were statistically analyzed using one-way ANOVA and Tukey's multiple comparisons at a significance level of P < 0.05.

    Results: Group S, SL1, and SL2 showed significantly increased SR values compared to the control group (P < 0.05); therefore, no significant differences were found among the SR values of Groups B, BL1, BL2, L1, and L2 and the control group (P > 0.05). Group S showed the highest SBS values, whereas the control group showed the lowest SBS values.

    Conclusion: Silica coating is the most effective method for resin bonding of high strength ceramic, but Er:YAG laser application decreased the effectiveness.

    Matched MeSH terms: Aluminum*; Aluminum Oxide
  13. Microwave-assisted synthesis of Zn/Al layered double hydroxide-(anthraquinone-2,6-disulfonate) nanocomposite
    bin Hussein MZ, Zainal Z, Hin TY, Tat OW
    J Microw Power Electromagn Energy, 2001;36(2):113-9.
    PMID: 15040529
    Nanocomposites of Zn/Al-layered double hydroxide(anthraquinone-2,6-disulfonate) were synthesized by spontaneous direct assembly of inorganic and organic phases from aqueous solution. Powder X-ray diffraction patterns showed that a pure, single nanocomposite phase of good crystallinity was obtained using 1.0 M antraquinone-2,6-disulfonate ion (AQ26) and aging at 80 degrees C using conventional heating for 7 days or 0.5 h under microwave radiation, and these samples are denoted as ZAAN26C or ZAAN26MH, respectively. Zn/Al-nitrate-layered double hydroxide synthesized by a conventional method (ZANLC) showed a basal spacing of 8.3 A while both the nanocomposites showed 18.8 A as a result of AQ26 intercalation. FTIR study showed that the resulting nanocomposites are free from nitrate, the co-anion present in the mother liquor, indicating that only AQ26 is preferred during intercalation for the formation of the nanocomposite. The Brunauer, Emmet and Teller (BET) and micropore surface areas for ZAAN26C decreased relative to the ZANLC from 16.2 to 4.7 and 1.6 to 1.3 m2/g, respectively. These results indicate that AQ26 can be rapidly interdcalated in layered double hydroxide using microwave-aging resulting in a nanocomposite.
    Matched MeSH terms: Aluminum Compounds/radiation effects; Aluminum Compounds/chemistry*
  14. The occurrence and potential ecological risk assessment of bauxite mine-impacted water and sediments in Kuantan, Pahang,Malaysia
    Kusin FM, Rahman MS, Madzin Z, Jusop S, Mohamat-Yusuff F, Ariffin M, et al.
    Environ Sci Pollut Res Int, 2017 Jan;24(2):1306-1321.
    PMID: 27771881 DOI: 10.1007/s11356-016-7814-7
    Recent bauxite mining activities in the vicinity of Kuantan, Pahang, have been associated with apparent environmental quality degradation and have raised environmental concerns among the public. This study was carried out to evaluate the overall ecological impacts on water and sediment quality from the bauxite mining activities. Water and sediment samples were collected at seven sampling locations within the bauxite mining areas between June and December 2015. The water samples were analyzed for water quality index (WQI) and distribution of major and trace element geochemistry. Sediment samples were evaluated based on geochemical indices, i.e., the enrichment factor (EF) and geoaccumulation index (I geo). Potential ecological risk index was estimated to assess the degree to which sediments of the mine-impacted areas have been contaminated with heavy metals. The results showed that WQIs of some locations were classified as slightly polluted and contained metal contents exceeding the recommended guideline values. The EFs indicated minimal to moderate enrichment of metals (Pb, Cu, Zn, Mn, As, Cd, Cr, Ni, Co, and Sr) in the sediments. I geo showed slightly to partially polluted sediments with respect to As at some locations. The potential ecological risk index (RI) showed that As posed the highest potential ecological risk with RI of 52.35-60.92 at two locations, while other locations indicated low risk. The findings from this study have demonstrated the impact of recent bauxite mining activities, which might be of importance to the local communities and relevant authorities to initiate immediate rehabilitation phase of the impacted area.
    Matched MeSH terms: Aluminum Oxide/analysis; Aluminum Oxide/toxicity*
  15. Fulltext Effect of multipath laser shock processing on microhardness, surface roughness, and wear resistance of 2024-T3 Al alloy
    Kadhim A, Salim ET, Fayadh SM, Al-Amiery AA, Kadhum AA, Mohamad AB
    ScientificWorldJournal, 2014;2014:490951.
    PMID: 24737973 DOI: 10.1155/2014/490951
    Laser shock processing (LSP) is an innovative surface treatment technique with high peak power, short pulse, and cold hardening for strengthening metal materials. LSP is based on the application of a high intensity pulsed laser beam (I > 1 GW/cm(2); t < 50 ns) at the interface between the metallic target and the surrounding medium (a transparent confining material, normally water) forcing a sudden vaporization of the metallic surface into a high temperature and density plasma that immediately develops inducing a shock wave propagating into the material. The shock wave induces plastic deformation and a residual stress distribution in the target material. In this paper we study the increase of microhardness and surface roughness with the increase of laser pulse energy in 2024-T3 Al alloy. The influence of the thickness of the confining layer (water) on microhardness and surface roughness is also studied. In addition, the effect of LSP treatment with best conditions on wear behaviors of the alloy was investigated.
    Matched MeSH terms: Aluminum/radiation effects*; Aluminum/chemistry*
  16. Fulltext Room temperature radiolytic synthesized Cu@CuAlO(2)-Al(2)O(3) nanoparticles
    Abedini A, Saion E, Larki F, Zakaria A, Noroozi M, Soltani N
    Int J Mol Sci, 2012;13(9):11941-53.
    PMID: 23109893 DOI: 10.3390/ijms130911941
    Colloidal Cu@CuAlO(2)-Al(2)O(3) bimetallic nanoparticles were prepared by a gamma irradiation method in an aqueous system in the presence of polyvinyl pyrrolidone (PVP) and isopropanol respectively as a colloidal stabilizer and scavenger of hydrogen and hydroxyl radicals. The gamma irradiation was carried out in a (60)Co gamma source chamber with different doses up to 120 kGy. The formation of Cu@CuAlO(2)-Al(2)O(3) nanoparticles was observed initially by the change in color of the colloidal samples from colorless to brown. Fourier transform infrared spectroscopy (FTIR) confirmed the presence of bonds between polymer chains and the metal surface at all radiation doses. Results of transmission electron microscopy (TEM), energy dispersive X-ray spectrometry (EDX), and X-ray diffraction (XRD) showed that Cu@CuAlO(2)-Al(2)O(3) nanoparticles are in a core-shell structure. By controlling the absorbed dose and precursor concentration, nanoclusters with different particle sizes were obtained. The average particle diameter increased with increased precursor concentration and decreased with increased dose. This is due to the competition between nucleation, growth, and aggregation processes in the formation of nanoclusters during irradiation.
    Matched MeSH terms: Aluminum Compounds/chemical synthesis*; Aluminum Compounds/chemistry
  17. Determination of trace metals in airborne particulate matter of Kuala Terengganu, Malaysia
    Mohd Tahir N, Poh SC, Suratman S, Ariffin MM, Shazali NA, Yunus K
    Bull Environ Contam Toxicol, 2009 Aug;83(2):199-203.
    PMID: 19436928 DOI: 10.1007/s00128-009-9751-3
    Results from the present study in Kuala Terengganu, Malaysia indicated a significant spatial variation but generally the total suspended particulate concentrations (mean = 17.2-148 microg/m(3)) recorded were below the recommended Malaysia guideline for total suspended particulate (mean of 24-h measurement = 260 microg/m(3)). Some of the elemental composition of particulate aerosol is clearly affected by non crustal sources, e.g. vehicular emission sources. Based on correlation and enrichment analyses, the elements could be grouped into two i.e. Pb, Cd and Zn group with sources from vehicular emission (r > 0.6; enrichment factor > 10) and Al, Fe, Mn and Cr group that appears to be of crustal origin (r > 0.6; enrichment factor < 10). It can also be concluded that the mean levels of Pb (1 ng/m(3)), Cd (0.02 ng/m(3)) and Zn (2 ng/m(3)) in the study area are generally lower than other urban areas in Malaysia (Pb < 181 ng/m(3); Cd < 6 ng/m(3); Zn < 192 ng/m(3)).
    Matched MeSH terms: Aluminum/analysis; Aluminum/chemistry
  18. Effect of powder to liquid ratio on tensile strength and glass transition temperature of alumina filled poly methyl methacrylate (PMMA) denture base material
    Mohamed SH, Arifin A, Mohd Ishak ZA, Nizam A, Samsudin AR
    Med J Malaysia, 2004 May;59 Suppl B:147-8.
    PMID: 15468861
    The aim of this study was to evaluate the mechanical properties and glass transition temperature (Tg) of a denture base material prepared from high molecular weight poly methyl methacrylate (PMMA) and alumina (Al2O3). The glass transition temperature was studied by using differential scanning calorimetry (DSC). The effect of powder-to-liquid ratio was investigated. The result showed that the tensile properties and the Tg were slightly effected by the powder-to-liquid ratio. The ratio of 2.2:1 by weight of powder to liquid was found to be the best ratio for mixing the material to give the best result in this formulation.
    Matched MeSH terms: Aluminum Oxide/analysis; Aluminum Oxide/chemical synthesis*
  19. Fulltext In vitro inhibition of histamine release behavior of cetirizine intercalated into Zn/Al- and Mg/Al-layered double hydroxides
    Hussein-Al-Ali SH, Al-Qubaisi M, Hussein MZ, Ismail M, Zainal Z, Hakim MN
    Int J Mol Sci, 2012;13(5):5899-916.
    PMID: 22754339 DOI: 10.3390/ijms13055899
    The intercalation of cetirizine into two types of layered double hydroxides, Zn/Al and Mg/Al, has been investigated by the ion exchange method to form CTZAN and CTMAN nanocomposites, respectively. The basal spacing of the nanocomposites were expanded to 31.9 Å for CTZAN and 31.2 Å for CTMAN, suggesting that cetirizine anion was intercalated into Layered double hydroxides (LDHs) and arranged in a tilted bilayer fashion. A Fourier transform infrared spectroscopy (FTIR) study supported the formation of both the nanocomposites, and the intercalated cetirizine is thermally more stable than its counterpart in free state. The loading of cetirizine in the nanocomposite was estimated to be about 57.2% for CTZAN and 60.7% CTMAN. The cetirizine release from the nanocomposites show sustained release manner and the release rate of cetirizine from CTZAN and CTMAN nanocomposites at pH 7.4 is remarkably lower than that at pH 4.8, presumably due to the different release mechanism. The inhibition of histamine release from RBL2H3 cells by the free cetirizine is higher than the intercalated cetirizine both in CTZAN and CTMAN nanocomposites. The viability in human Chang liver cells at 1000 μg/mL for CTZAN and CTMAN nanocomposites are 74.5 and 91.9%, respectively.
    Matched MeSH terms: Aluminum Hydroxide/pharmacology*; Aluminum Hydroxide/chemistry
  20. Fulltext The Influence of Ziegler-Natta and Metallocene Catalysts on Polyolefin Structure, Properties, and Processing Ability
    Shamiri A, Chakrabarti MH, Jahan S, Hussain MA, Kaminsky W, Aravind PV, et al.
    Materials (Basel), 2014 Jul 09;7(7):5069-5108.
    PMID: 28788120 DOI: 10.3390/ma7075069
    50 years ago, Karl Ziegler and Giulio Natta were awarded the Nobel Prize for their discovery of the catalytic polymerization of ethylene and propylene using titanium compounds and aluminum-alkyls as co-catalysts. Polyolefins have grown to become one of the biggest of all produced polymers. New metallocene/methylaluminoxane (MAO) catalysts open the possibility to synthesize polymers with highly defined microstructure, tacticity, and steroregularity, as well as long-chain branched, or blocky copolymers with excellent properties. This improvement in polymerization is possible due to the single active sites available on the metallocene catalysts in contrast to their traditional counterparts. Moreover, these catalysts, half titanocenes/MAO, zirconocenes, and other single site catalysts can control various important parameters, such as co-monomer distribution, molecular weight, molecular weight distribution, molecular architecture, stereo-specificity, degree of linearity, and branching of the polymer. However, in most cases research in this area has reduced academia as olefin polymerization has seen significant advancements in the industries. Therefore, this paper aims to further motivate interest in polyolefin research in academia by highlighting promising and open areas for the future.
    Matched MeSH terms: Aluminum
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