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RISS 인기검색어
- 검색키워드
- 저자 : Abdullah Yassin (검색결과 5 건)
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Study on tool wear mechanisms in milling laser sintered material
Abdullah Yassin,Takashi Ueda,Tatsuaki Furumoto,Mohd Sanusi Abdul Aziz,Ryutaro Tanaka,Akira Hosokawa 대한기계학회 2010 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.24 No.1
This paper investigates tool wear mechanisms of a ball end mill in cutting laser sintered material. Cutting edge temperature is measured by using a three-color pyrometer with an optical fiber. Bulk carbon steel JIS S55C is selected as the standard steel. Experimental results show that tool life in cutting sintered material is shorter than that in cutting JIS S55C. Observations by SEM show that adhesion of the work material and micro chipping are the main wear mechanisms in cutting sintered material. The corresponding cutting edge temperature shows a continuous increase as wear evolves with cutting time.
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Potential of Activated Carbon Derived from Local Common Reed in the Refining of Raw Cane Sugar
Ibrahim D-Abdullah,Badie S. Girgis,Yassin M. Tmerek,Elsaid H. Badawy 한국탄소학회 2010 Carbon Letters Vol.11 No.3
Common reed (Fragmites australis), a local invasive grass, was investigated as a possible feedstock for the production of activated carbon. Dried crushed stems were subjected to impregnation with phosphoric acid (30, 40 and 50%) followed by pyrolysis at 400~500℃ with final washing and drying. Obtained carbons were characterized by determining: carbon yield, ash content, slurry pH, textural properties and capacity to remove color bodies from factory-grade sugar liquor. Produced carbons possessed surface area up to 700 m2/g, total pore volumes up to 0.37 cm3/g, and proved to be microporous in nature. Decolorization of hot sugar liquor at 80℃ showed degrees of color removal of 60 up to 77% from initial color of 1100~1300 ICU, at a carbon dose of 1.0 g/100 ml liquor. No correlation seems to hold between synthesis conditions and % R but depends on the degree of microporosity. A commercial activated carbon N showed a comparative better color removal capacity of 91%. Common reed proved to be a viable carbon precursor for production of good adsorbing carbon suitable for decolorization in the sugar industry, as well as in other environmental remediation processes.
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X-ray Diffraction Patterns of Activated Carbons Prepared under Various Conditions
Badie S. Girgis,Yassin M. Temerk,Mostafa M. Gadelrab,Ibrahim D. Abdullah 한국탄소학회 2007 Carbon Letters Vol.8 No.2
A series of activated carbons (ACs) were derived from sugarcane bagasse under two activation schemes: steam-pyrolysis at 600-800℃ and chemical activation with H3PO4 at 500℃. Some carbons were treated at 400, 600℃, or for 1-3 h, and/or in flowing air during pyrolysis of acid-impregnated mass. XRD profiles displayed two broad diffuse bands centered around 2θ=23 and 43˚, currently associated with diffraction from the 002 and 100/101 set of planes in graphite, respectively. These correspond to the interlayer spacing, Lc, and microcrystallite lateral dimensions, La, of the turbostratic (fully disordered) graphene layers. Steam pyrolysis-activated carbons exhibit only the two mentioned broad bands with enhancement in number of layers, with temperature, and small decrease in microcrystallite diameter, La. XRD patterns of H3PO4-ACs display more developed and separated peaks in the early region with maxima at 2θ=23, 26 and 29˚, possibly ascribed to fragmented microcrystallites (or partially organized structures). Diffraction within the 2θ=43˚ is still broad although depressed and diffuse, suggesting that the intragraphitic layers are less developed. Varying the conditions of chemical activation inflicts insignificant structural alterations. Circulating air during pyrolysis leads to enhancement of the basic graphitic structure with destruction and degradation in the lateral dimensions.
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X-ray Diffraction Patterns of Activated Carbons Prepared under Various Conditions
Girgis, Badie S.,Temerk, Yassin M.,Gadelrab, Mostafa M.,Abdullah, Ibrahim D. Korean Carbon Society 2007 Carbon Letters Vol.8 No.2
A series of activated carbons (ACs) were derived from sugarcane bagasse under two activation schemes: steam-pyrolysis at $600-800^{\circ}C$ and chemical activation with $H_3PO_4$ at $500^{\circ}C$. Some carbons were treated at 400, $600^{\circ}C$, or for 1-3 h, and/or in flowing air during pyrolysis of acid-impregnated mass. XRD profiles displayed two broad diffuse bands centered around $2{\theta}=23$ and $43^{\circ}$, currently associated with diffraction from the 002 and 100/101 set of planes in graphite, respectively. These correspond to the interlayer spacing, Lc, and microcrystallite lateral dimensions, La, of the turbostratic (fully disordered) graphene layers. Steam pyrolysis-activated carbons exhibit only the two mentioned broad bands with enhancement in number of layers, with temperature, and small decrease in microcrystallite diameter, La. XRD patterns of $H_3PO_4$-ACs display more developed and separated peaks in the early region with maxima at $2{\theta}=23$, 26 and $29^{\circ}$, possibly ascribed to fragmented microcrystallites (or partially organized structures). Diffraction within the $2{\theta}=43^{\circ}$ is still broad although depressed and diffuse, suggesting that the intragraphitic layers are less developed. Varying the conditions of chemical activation inflicts insignificant structural alterations. Circulating air during pyrolysis leads to enhancement of the basic graphitic structure with destruction and degradation in the lateral dimensions.
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Study on laser assisted milling of ferrous based consolidated material
Tatsuaki Furumoto,Takashi Ueda,Teruyuki Osaka,Abdullah Yassin,Akira Hosokawa,Ryutaro Tanaka 대한기계학회 2010 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.24 No.1
This study deals with the laser beam assisted milling to improve the machinability of a consolidated structure formed by layered manufacturing processes. The laser beam used is a continuous CO2 laser with a maximum output power of 100 W. The metal powder for layered manufacturing is a ferrous-based mixture. To investigate the influence of laser conditions on the machinability, specific cutting force,tool wear and tool temperature of the flank face are measured. The results showed that the specific cutting force of the consolidated structure was decreased by the effect of energy input on the structure surface. The progress of wear on the flank face assisted by the laser beam was 20% slower due to the softening of the consolidated structure and the melting of the powder which remained on the structure surface. The dimensional accuracy and surface finishing of the consolidated structure were influenced by the rise of the tool temperature on the flank face.
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