Papers by Keyword: Magnetic Flux

Abstract: The current investigation aims to synthesize MgFe₂O₄ magnetic nanoparticle and measure the thermal conductivity of MgFe₂O₄ ferrofluid. Prepared MgFe₂O₄ nanoparticle's structural characterization, the concentration of constituents, and surface morphology were analyzed using XRD, EDAX, and TEM respectively. This study also analyses the influence of magnetic flux on the thermal conductivity of MgFe₂O₄/ EG: H₂O (60:40) based ferrofluids formed by the two-step method. Thermal conductivity of ferrofluid measured at different volume fractions (ranging from 0.01% to 0.20%) show that thermal conductivity augmented with an escalation in volume fraction and the highest enhancement of 10.32% was reached at 0.20% volume fraction. Results indicate that the applied magnetic flux improves the thermal conductivity of ferrofluid from 10.32% to 14.75% at 0.20% volume fraction and 350 Gauss Magnetic flux.

Abstract: The replacement of NdFeB magnets by ferrite magnets is discussed. For motors, remanence is relevant, implying in a volume three times that of NdFeB, when the relevant index of merit is remanence. However, if the relevant issue is the BH_max (maximum energy product), the volume for replacement should be ten times larger. The high resistivity of ferrites is a big advantage for motors. The temperature of operation is also relevant, because NdFeB magnets loss coercivity even with small increase of temperature. Different applications are discussed, as for instance, motors for electric cars and wind turbines. The choice of the proper volume depends on the evaluation of demagnetizing field in the condition of operation.

Abstract: There is an ever increasing demand for use of inductive speed sensors in a broad range of applications. They are used in typical applications such as cam and crank shaft position/speed and wheel and turbo shaft speed measurement. This paper describes the type of inductive sensor found on vehicles and the difficulties of detecting at low speeds. In the laboratory of Mechatronics an experimental device has been done to measure the speed using an inductive speed sensor. The experimental results are satisfactory and show the possibility of the inductive sensors to be used in automotive industry.

Abstract: This research is aimed at designing a suitable electromagnetic valve actuator (EMVA) which could efficiently improve energy saving performance of engine for scavenging two-stroke engine. Our Group simplified the GM’s EMVA and made it suitable for the engine used in experiment. CFD and mathematical modeling software were used to help our designing. According to the result of CFD, the design meets the intake requirements of the engine.

Abstract: Memristor is a nonlinear resistance with the ability of memory and its resistance depends on the amount of charge or magnetic flux. As a new circuit component, the memristor is not only expected to promote the evolution of electronic industry but also has huge potential application in many fields because of its small size, low energy consumption and be large scale integrated easily. In this paper according to the mathematical model of memristor based on a piecewise-linear function, the characteristics of memristor series-parallel connection circuit are analyzed by MATLAB and SPICE simulations. A series of simulation results show that the memristive series-parallel network is still a nonlinear element, the resistance value of memristor depends on the initial condition greatly and the electronic characteristics are more complex. It is also applied to the ladder signal generator which can be used in the controller circuit.

Abstract: The magnetic domain structures of the cubic parent phase (high-temperature phase) in ferromagnetic shape memory alloys (SMAs) have been studied by electron holography. In a Ni51Fe22Ga17 alloy, the magnetic flux distribution in the parent phase changes dramatically before the onset of martensitic transformation. In contrast, a Ni45Co5Mn36.7In13.3 alloy—a recently developed ferromagnetic SMA—does not show appreciable changes in the magnetic domain structure upon cooling. The anomaly observed in the Ni51Fe22Ga17 alloy appears to be due to lattice distortions, which become more pronounced as the temperature approaches the martensitic transformation start temperature, Ms.

Abstract: Polishing the inner surface of slender pipe is very difficult. Because a usual tool cannot into the inner surface of the slender pipe, and automation do not achieved easily; the eye is unable to see, even if handmade is also very difficult. Utilize the characteristic of the magnetic force line may penetrate the non-magnetic material, may using the magnetic abrasive finishing (MAF) method complete to the inner surface of the slender pipe precise polishing is a preferable method and already obtained the good processing effect through the experiment. Therefore, this paper analysis and explanation the finishing principle and experiment device as well as collocation position of magnetic poles etc best experimental condition.

Abstract: Utilize the characteristic that magnetic force line may penetrate the non-magnetic material, using the magnetic abrasive finishing (MAF) method complete to the non-magnetic small workpiece surface precise processing. In order to enhance polishing efficiency, usually with the magnetic particles and abrasive particles mixes together in the sinter method or the cementation method, the cost is higher; the variety is not also complete. Therefore, use the simply mixed method mixed the ferromagnetism iron particles, the alumina particles and the lipin, directly participates in magnetism polishing, already obtained the good processing effect through the experiment. This paper analysis and explanation the best experimental condition such as the granularity proportion of the ferromagnetism iron particles and the alumina particles etc.

Abstract: Because of the raw material elements and its purity and so on, the Nd-Fe-B permanent magnet, the strongest magnetic material, which needs artificial synthesis, can hardly be used directly. The performance of the permanent magnet has not yet been greatly developed owing to the limitation of the artificial synthesizing technology, of the powder sintering technology and that of the application. In this paper, the magnetic abrasive machining method as a new application is put forward, and from this viewpoint, are discussed the performance and the processing technology of the permanent magnet and the magnetic abrasive machining method. A sintering route combining the direction heat treatment technique to increase the magnetic energy is suggested.

Abstract: Magnetic characteristics observed in BiSrCaCuO superconductor were studied. In the measurement of differential conductance, it was cleared that the mechanism of magnetic memory effect couldn't be explained by using conventional flux flow model. By changing the density of external magnetic flux, changes in inductance of a coil in which a superconducting bar inserted were also measured. The results showed that the filament model was valid to explain the mechanism of the occurrence of a voltage in superconducting sample. It was concluded that the electromagnetic characteristics arose from the interaction between the trapped magnetic flux and weak link of the filament formed in the superconducting bulk.