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Full-Text Articles in Social and Behavioral Sciences
Stability Enhancement Of Magnetic Levitation Ball System With Two Controlled Electomagnets, Hai Huang, Haiping Du, Weihua Li
Stability Enhancement Of Magnetic Levitation Ball System With Two Controlled Electomagnets, Hai Huang, Haiping Du, Weihua Li
Faculty of Engineering and Information Sciences - Papers: Part A
Magnetic levitation ball system is a highly nonlinear and unstable system. If the system is linearised at the equilibrium point, the achievable balance range of the magnetically levitated ball is very short with one electromagnet. This paper presents an improved magnetic levitation ball system, that contains two electromagnets, where one electromagnet is set above the magnetic ball for pulling, and another one is set under the magnetic ball for pushing. In addition, this paper applies a 2-DOF (degree-of-freedom) PID (proportional-integral-derivative) controller instead of 1-DOF PID for the control of the two electromagnets so that they can work corporately to make …
High Di-Electric Constant Nano-Structure Ceramics Synthesis Using Novel Electric Discharge Assisted Mechanical Milling And Magneto Ball Milling And Its Properties, Azrin A. Chowdhury, Andrzej Calka, David Wexler, Konstantin Konstantinov
High Di-Electric Constant Nano-Structure Ceramics Synthesis Using Novel Electric Discharge Assisted Mechanical Milling And Magneto Ball Milling And Its Properties, Azrin A. Chowdhury, Andrzej Calka, David Wexler, Konstantin Konstantinov
Faculty of Engineering and Information Sciences - Papers: Part A
The conventional method to prepare functional oxides is ceramicpowder- based processing typically via solid-state reaction of microcrystalline starting powders at high temperatures. Disadvantages of this approach include the high temperatures of reaction, limited degree of product chemical homogeneity and difficulties in achieving rapid sintering. Various chemicalbased processing routes have been developed to prepare powders of more homogeneous composition, improved reactivity and sintering ability at low temperatures. Regardless of the route chosen to synthesise complex oxides, almost all of them require lengthy heat treatment schedules that usually exceed 10 h, as well as multi-stage processing steps. We describe two approaches to …
Effect Of Gallium Doping And Ball Milling Process On The Thermoelectric Performance Of N-Type Zno, Priyanka Jood, Germanas Peleckis, Xiaolin Wang, S X. Dou
Effect Of Gallium Doping And Ball Milling Process On The Thermoelectric Performance Of N-Type Zno, Priyanka Jood, Germanas Peleckis, Xiaolin Wang, S X. Dou
Faculty of Engineering and Information Sciences - Papers: Part A
We report a systematic investigation of the thermoelectric properties of n-type Ga-doped ZnO synthesized using different ball milling conditions. Samples fabricated by the high-energy ball milling resulted in a highly dense layered structure with randomly distributed voids. These samples measured the lowest room temperature thermal conductivity, i.e., 27 W/mK due to increased phonon scattering. Furthermore, the Ga:ZnO system showed a metal–semiconductor transition above 300 K with transition temperature decreasing with increasing doping level. Measurement of the activation energy revealed the presence of one donor level around 3.9–7.8 meV and a deeper donor level around 15.4–18.1 meV below the conduction band …
The Formation Of Ternary Compound Fe3mo3c By Ball Milling, L M. Di, Andrzej Calka, Z L. Li, J S. Williams
The Formation Of Ternary Compound Fe3mo3c By Ball Milling, L M. Di, Andrzej Calka, Z L. Li, J S. Williams
Faculty of Engineering and Information Sciences - Papers: Part A
Ball milling of Mo in nitrogen and ammonia gases has been studied. After heating, the formation of an intriguing ternary compound, Fe3Mo3C1−x , was observed as a result of Fe (and C) contamination from the milling apparatus. For a comparison, mechanical alloying of Fe–Mo–C powders with a stoichiometric composition of Fe3Mo3C was also performed and again an Fe–Mo–C alloy was obtained after milling.Thermal analysis shows a single transition peak for the formation of both the Fe3Mo3C phase in the latter case and also for Fe3 …
Low Temperature Synthesis Of Al-Aln Composites From A Nanostructure Made By Controlled Magneto-Ball Milling Of Al In Ammonia, Andrzej Calka, J I. Nikolov, G H. J Wantenaar
Low Temperature Synthesis Of Al-Aln Composites From A Nanostructure Made By Controlled Magneto-Ball Milling Of Al In Ammonia, Andrzej Calka, J I. Nikolov, G H. J Wantenaar
Faculty of Engineering and Information Sciences - Papers: Part A
The formation of an AlN compound in ball milled Al powder in ammonia was studied. In this work a magneto‐ball milling device with controlled ball movement was used. The end milling product was an Al based nanostructure. This product can be transformed into an AlN‐Al nanocomposite upon heating below the melting point of Al. It was found that the level of unreacted Al is dependent on milling time. The maximum amount of AlN was 88.28 wt %. The structure of as‐milled and annealed samples was investigated using x‐ray diffractometry and transmission electron microscopy. Differential thermal analysis was performed on as‐milled …