Dan Eusoff | UPM - Universiti Putra Malaysia (original) (raw)
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Transactions of the Indian Institute of Metals, 2014
The occurrence of pattern formation within physical dimension and mechanical property changes was... more The occurrence of pattern formation within physical dimension and mechanical property changes was systematically investigated based on the addition of various amounts of pre-alloyed Astaloy E and carbon to iron powder. Powder samples were prepared in a similar manner by mixing in a Y-type mixer, compacting in a floating die under constant pressure and sintering in a hydrogen atmosphere tunnel furnace at 1,120°C for 45 min. An optical microscope equipped with image analysis was employed to study the microstructure. Physical properties, such as the green density, sintered density and dimensional changes, as well as the hardness were measured. The results indicate that the addition of Astaloy E and carbon results in increased green density, sintered density and hardness. An increase in the carbon content resulted in physical dimension growth of the parts.
2006 International Conference on Nanoscience and Nanotechnology, 2006
Page 1. Influence of anode surface temperature in a continuously-fed arc discharge depositing car... more Page 1. Influence of anode surface temperature in a continuously-fed arc discharge depositing carbon nanotubes Hamdan Mohamed Yusoff, John Abrahamson*, and Rahul Shastry *Chemical and Process Engineering Department ...
Transactions of the Indian Institute of Metals, 2014
The occurrence of pattern formation within physical dimension and mechanical property changes was... more The occurrence of pattern formation within physical dimension and mechanical property changes was systematically investigated based on the addition of various amounts of pre-alloyed Astaloy E and carbon to iron powder. Powder samples were prepared in a similar manner by mixing in a Y-type mixer, compacting in a floating die under constant pressure and sintering in a hydrogen atmosphere tunnel furnace at 1,120°C for 45 min. An optical microscope equipped with image analysis was employed to study the microstructure. Physical properties, such as the green density, sintered density and dimensional changes, as well as the hardness were measured. The results indicate that the addition of Astaloy E and carbon results in increased green density, sintered density and hardness. An increase in the carbon content resulted in physical dimension growth of the parts.
Mass production of carbon nanotubes (CNTs) by a cost effective process is still a challenge for f... more Mass production of carbon nanotubes (CNTs) by a cost effective process is still a challenge for further research and application of CNTs. Our group has focussed on the deposition of CNTs on a continuously-fed carbon substrate via arc discharge at atmospheric pressure. This process produces MWNTs using carbon from the substrate. The method differs in other respects from the conventional batch arc discharge method by using lower currents (< 20 A) and larger inter-electrode gaps. To help define the local conditions of nanotube growth, the substrate surface temperature (T s ) was measured by optical pyrometry. Here, we report the influence of inter-electrode gap, substrate velocity and arc current on this temperature. It is found that carbon nanotube growth is favourable over a certain temperature range and retention time in the arc. To further understand the effect of arc parameters, we used a computer simulation to model the arc plasma. Computational fluid dynamic (CFD) software, Comsol Multiphysics, was used to simulate the temperature distribution and flow properties of the arc plasma. It was found necessary to include dusty plasma conductivity near to the electrodes to adequately represent observed arc behaviour.
Transactions of the Indian Institute of Metals, 2014
The occurrence of pattern formation within physical dimension and mechanical property changes was... more The occurrence of pattern formation within physical dimension and mechanical property changes was systematically investigated based on the addition of various amounts of pre-alloyed Astaloy E and carbon to iron powder. Powder samples were prepared in a similar manner by mixing in a Y-type mixer, compacting in a floating die under constant pressure and sintering in a hydrogen atmosphere tunnel furnace at 1,120°C for 45 min. An optical microscope equipped with image analysis was employed to study the microstructure. Physical properties, such as the green density, sintered density and dimensional changes, as well as the hardness were measured. The results indicate that the addition of Astaloy E and carbon results in increased green density, sintered density and hardness. An increase in the carbon content resulted in physical dimension growth of the parts.
2006 International Conference on Nanoscience and Nanotechnology, 2006
Page 1. Influence of anode surface temperature in a continuously-fed arc discharge depositing car... more Page 1. Influence of anode surface temperature in a continuously-fed arc discharge depositing carbon nanotubes Hamdan Mohamed Yusoff, John Abrahamson*, and Rahul Shastry *Chemical and Process Engineering Department ...
Transactions of the Indian Institute of Metals, 2014
The occurrence of pattern formation within physical dimension and mechanical property changes was... more The occurrence of pattern formation within physical dimension and mechanical property changes was systematically investigated based on the addition of various amounts of pre-alloyed Astaloy E and carbon to iron powder. Powder samples were prepared in a similar manner by mixing in a Y-type mixer, compacting in a floating die under constant pressure and sintering in a hydrogen atmosphere tunnel furnace at 1,120°C for 45 min. An optical microscope equipped with image analysis was employed to study the microstructure. Physical properties, such as the green density, sintered density and dimensional changes, as well as the hardness were measured. The results indicate that the addition of Astaloy E and carbon results in increased green density, sintered density and hardness. An increase in the carbon content resulted in physical dimension growth of the parts.
Mass production of carbon nanotubes (CNTs) by a cost effective process is still a challenge for f... more Mass production of carbon nanotubes (CNTs) by a cost effective process is still a challenge for further research and application of CNTs. Our group has focussed on the deposition of CNTs on a continuously-fed carbon substrate via arc discharge at atmospheric pressure. This process produces MWNTs using carbon from the substrate. The method differs in other respects from the conventional batch arc discharge method by using lower currents (< 20 A) and larger inter-electrode gaps. To help define the local conditions of nanotube growth, the substrate surface temperature (T s ) was measured by optical pyrometry. Here, we report the influence of inter-electrode gap, substrate velocity and arc current on this temperature. It is found that carbon nanotube growth is favourable over a certain temperature range and retention time in the arc. To further understand the effect of arc parameters, we used a computer simulation to model the arc plasma. Computational fluid dynamic (CFD) software, Comsol Multiphysics, was used to simulate the temperature distribution and flow properties of the arc plasma. It was found necessary to include dusty plasma conductivity near to the electrodes to adequately represent observed arc behaviour.