Muhammad Asri Idris, Associate Professor Dr.
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This page provides access to scholarly publication by UniMAP Faculty members and researchers2024-03-28T22:58:21ZIonic conductivity and crystal structure for the Li3−2xCr2−xTax(PO4)3 system
http://dspace.unimap.edu.my:80/xmlui/handle/123456789/35187
Ionic conductivity and crystal structure for the Li3−2xCr2−xTax(PO4)3 system
Hiromichi, Aono; Muhammad Asri, Idris, Dr.; Yoshihiko, Sadaoka
The monoclinic phase (P21/n) was formed for 0≤x≤0.6 and the NASICON-type rhombohedral phase (R3̄c) was obtained for the region 0.8≤x≤1.2 in the Li3−2xCr2−xTax(PO4)3 system. The activation energy for Li+migration was ca. 0.45 eV for the monoclinic structure and ca. 0.36 eV for the rhombohedral structure. The maximum conductivity of 8.4×10−6 S cm−1 at 298 K was obtained for x=0.8 of the Li3−2xCr2−xTax(PO4)3system. The conductivity of LiCrTa(PO4)3 was enhanced about three to five times by the addition of the lithium salt due to the improvement of the sinterablity. The maximum conductivity was 2.4×10−5 S cm−1 at 298 K for LiCrTa(PO4)3–0.2Li3BO3.
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2004-01-01T00:00:00ZOverview of pathogenic micro-organisms destruction in contaminated water by oxide photocatalysis
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Overview of pathogenic micro-organisms destruction in contaminated water by oxide photocatalysis
Noor Azira, Mohd Noor; Muhammad Asri, Idris, Dr.; Dewi Suriyani, Che Halin, Dr.; Mohd Nazree, Derman, Dr.; Mohd Arif Anuar, Mohd Salleh
The titanium dioxide (TiO2) is a semiconductor oxide photocatalys, which is chemically and biologically inert but exhibits excellent photolytic activity in the ultraviolet (UV) region. Progress in photocatalytic water disinfection requires understanding both concepts of TiO2 semiconductor as well the biochemistry of microorganisms. The advantage and disadvantage for current water purifications are discussed. Finally, the photocatalytic reactions to water disinfection and detoxification using solar energy.
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2013-01-01T00:00:00ZRecycling Agricultural Waste from Palm Shells during Electric Arc Furnace Steelmaking
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Recycling Agricultural Waste from Palm Shells during Electric Arc Furnace Steelmaking
Nur Farhana, M. Yunos; Magdalena, Zaharia; M. Asri, Idris; Nath, Dilip; Khanna, Rita; Sahajwalla, Veena
The present study is focused on developing novel recycling of palm shell wastes as a carbon resource in electric arc furnace (EAF) steelmaking. Metallurgical coke was replaced by palm shells, and interactions with EAF slag were investigated at 1550 °C in a laboratory-scale reactor using the sessile-drop approach in an argon atmosphere (1 L/min). The palm shells were devolatilized in a nitrogen atmosphere at 450 °C, while coke was used without initial processing. The quantitative estimation of the slag droplet volume was performed using the Vt/V0 ratio as a measure of slag foaming. For coke, the volume ratio decreased from 1.0 to 0.8 in the first 10 min with no considerable fluctuations. However, palm shell char showed considerably different trends with continuous fluctuations, reaching a maximum value of Vt/V0 = 1.3, indicating a higher extent of gas entrapped into the slag matrix compared to coke. Off-gas emissions were monitored and correlated with dynamic changes in volume as a result of iron-oxide-rich EAF slag and carbon. The rates of total gas generation (CO + CO2) from palm shell char were comparable to those seen in coke; however, the gases released from palm shell were an extent over a longer period of time, which allowed for their entrapment in the slag matrix, enhancing the volume of the slag. A thermogravimetric analyzer coupled with a mass spectrometer (TGA–MS) was used to study the behavior of coke and palm shells at high temperatures, with a focus on gas formation. The weight loss profiles, gas formation, and product distribution were significantly different between the two carbonaceous samples. It was found that more gases were released from palm shells than from the raw coke. Palm shells showed significant weight loss in the first 500 °C; however, a considerable amount of gases was evolved at temperatures higher than 1000 °C that might participate in the subsequent carbon/slag reactions. Optical microscopy images of the cross-section of the slag/palm shell sample showed trapped gas bubbles and reduced iron dispersed throughout the slag matrix. These results indicate that partial replacement of coke with palm shells is not only viable but efficient, leading to improved/sustained interactions with EAF slag.
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2012-01-19T00:00:00ZAnalysis of particle size and XRD in ZnO-based varistor
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Analysis of particle size and XRD in ZnO-based varistor
Noor Azira, Mohd Noor; Mohabattul Zaman B. S., NS Bukhari, Prof Madya; Muhammad Asri, Idris; Noor Mariamadzliza, Mohd Nan
ZnO varistors doped with Bi2O3, Sb2O3, CoO, MnO2 and Cr2O3 were prepared separately by
two mixing processes: conventional and masterbatching mixed-oxide process method.
After the mixing process, the ZnO-based varistor powders were milled using planetary
ball mill at 200, 300, 400 and 500 rpm. Particle size analysis and XRD analysis were
used to study the differences after milling process in ZnO-based varistor powder. The
particle sizes of varistor powder were reduced and new compound encountered after
milling process.
International Conference on X-Rays and Related Techniques in Research and Industry (ICXRI 2010) jointly organized by Universiti Malaysia Perlis (UniMAP) and X-Ray Application Malaysia Society (XAPP), 9th - 10th June 2010 at Aseania Resort Langkawi, Malaysia.
2010-06-09T00:00:00Z