Adsorption of Iron (II) Ion by Using Magnetite-Bentonite-Based Monolith from Water

In this study, iron removal was carried out by the adsorption process as a well-known method of removing heavy metal. Natural bentonite with magnetic properties in a monolithic form or Magnetite-Bentonite-based Monolith (MBM) adsorbent was used as an adsorbent to remove Iron (II) ion from the aqueous solution. The magnetic properties of adsorbents are obtained by adding magnetite (Fe3O4), which is synthesized by the coprecipitation process. The characterization of magnetic properties was performed using the Vibrating Sample Magnetometer (VSM). VSM results showed that the magnetic particles were ferromagnetic. Adsorption efficiency, isotherm model, and adsorption kinetics were investigated in a batch system with iron solution concentration varied from 2 to 10 mg/L and magnetite loading at 2% and 5% w/w. The highest removal efficiency obtained reached 89% with a 5% magnetite loading. The best fit to the data was obtained with the Langmuir isotherm (non-linear) with maximum monolayer adsorption capacity (Qo) at 5% magnetic loading MBM adsorbent is 0.203 mg/g with Langmuir constants KL and aL are 2.055 L/g and 10.122 L/mg respectively. The pseudo-first-order (non-linear) kinetic model provides the best correlation of the experimental data with the rate of adsorption (k1) with magnetite loading 2% and 5%, respectively are 0.024 min-1 and 0.022 min-1.

Design and analysis of a novel variable flux spoke-type motor for washing machines

This paper deals with the design and analysis of a novel variable flux spoke-type motor (VFSM) for washing machines by focally considering the performance at the laundry and spin-drying operating modes. The key design goal is to obtain the high efficiency for the two operating modes. At the laundry mode, the ferrite and AlNiCo magnets are utilized together as the excitations to obtain a high magnetic loading, thus to obtain high torque and efficiency. At the spin-drying mode, the AlNiCo magnets are demagnetized by a pulse negative d-axis current to reduce magnetic flux density, thus to obtain low iron loss and high efficiency. The outer rotor structure with the spoke-type magnet configuration is utilized to enhance the high output performances. The D2L method is utilized to design the key parameters of the VFSM. To demonstrate the superiority of the designed VFSM, the electromagnetic characteristics are predicted by the finite element method (FEM). As a result, the volume size of the proposed VFSM is decreased by 19.4%, and the efficiency at the low-speed laundry mode is increased by 25.4%, when compared to the referenced commercial washing machine motor.

Six observational pieces of evidence against corotation as the main cause for the aurora at Jupiter

<p>The Main Emissions are the most recognizable feature of the aurorae at Jupiter and they are responsible for roughly 1/3rd of the total emitted power. They form an ever-present and quasi-continuous ring of emission centered on the magnetic poles. The most widely accepted explanation for these auroral emissions involves a current system related to the corotation enforcement of the plasma in the Jovian magnetosphere. Models based on this theory explain many characteristics of the aurorae. However, recent observations from the NASA Juno spacecraft and the ESA/NASA Hubble Space Telescope, complemented by previous results from the NASA Galileo spacecraft, challenge this theoretical framework. In this presentation, we will review six specific sets of observations contradictory with expectations from the corotation enforcement theory:</p> <ol> <li> dawn/dusk asymmetries in the particle angular velocity and magnetic field bend-back,</li> <li>fragmented and asymmetric field-aligned currents,</li> <li>dawn/dusk brightness asymmetry,</li> <li>global auroral brightening in response to solar wind compression,</li> <li>auroral brightness variations as a response to magnetic loading/unloading,</li> <li>energy distribution of the charged particles precipitating into the main auroral emissions.</li> </ol> <p>We will expose their implications for the modelling of the Jovian magnetosphere and aurorae and we will discuss promising paths forward. </p>

Slot Filling Factor Calculation and Electromagnetic Performance of Single Phase Electrically Excited Flux Switching Motors

For variable speed applications, flux controlling capability of electrically excited flux switching motors (EEFSMs) attract researchers’ attention. However, low copper slot filling factor of the EEFSM with standard stator slot vitiates the electromagnetic performance and efficiency. This paper has proposed a new Octane Modular Stator (OMS) EEFSM model that has pentagonal stator slot and high copper slot filling factor. Copper slot filling factor is deliberated analytically for the proposed model and designs with standard stator slots, i.e., trapezoidal and rectangular. Electromagnetic performance of the OMS, Rectangular Stator Slot (RSS) and Trapezoidal Stator Slot (TSS) EEFSM designs are evaluated by finite element analysis (FEA) through JMAG v18.1 FEA solver. The proposed OMS EEFSM model has 9% higher copper slot filling factor in comparison with standard stator slots designs under same geometric parameters. The high copper slot filling factor of the proposed OMS EEFSM model has improved performance in term of low electric and magnetic loading.

A Two Dimensional Finite Element Model for Prestress Effects on Magnetoelectric Laminated Composites

Magnetoelectric (ME) composites are viable candidates for use in numerous applications owing to their multifunctional capabilities. These composites develop voltages across the piezo-electric phase under external magnetic fields. Numerous models available in literature consider the magnetostriction under pure magnetic loading. However, fabrication of ME composites results in development of compressive stresses on the magnetostrictive layer, which leads to a poor ME response and hence an initial effective tensile prestress to the magnetostrictive phase is required to either compensate or enhance the ME coupling. In this work, the ME response of an unsymmetric laminate is predicted using a finite element procedure based on Mindlin plate theory, giving due consideration the magnetostrictive nonlinearity, the direction of the applied field and the effect of the stress state on the magnetostrictive response. The model predicts that initial shear stresses, positive or negative, provide the best enhancement to the ME coupling.

Improving Inductive Welding System Performance with Soft Magnetic Composites

Inductive welding is a popular method for making metallic tubes used in a variety of industries. A majority of these induction tube welding systems use internal magnetic flux controllers (impeders) to limit the current flowing on the ID of the tube under the induction coil. As higher power, solid state IGBT power supplies become more widely available for tube welding, and demand for lower cost tubes with higher strength to weight ratios increases, magnetic loading of these impeders is also increasing. Traditionally, impeders are made of ferrites which have a low saturation flux density and can become saturated in these demanding conditions. Saturation of the impeder results in greater currents on the tube ID and lower process efficiency and weld quality. In order to expand the upper operating range of these more demanding systems while maintaining the weld quality, a change in impeder material from ferrites to soft magnetic composites (SMC) with greater saturation flux densities is suggested, as well as the addition of external magnetic controllers (bridges). In this paper, a comparison is made between induction systems with impeders constructed from traditional ferrites and those utilizing bridges and impeders made from SMCs. To do this, a simulation study will be used to estimate impeder flux density, required coil current, and temperature distribution at the end of heating when using impeders made of the two materials, with and without bridges. By soft coupling 3-D electromagnetic models with 2-D electromagnetic and thermal models, a fast and accurate depiction of the welding process can be achieved. A case study is presented comparing simulation results to experimental results.

Temperature Change of Spindle Using Non-Contact Controllable Excitation and Response Measurement

The main error source effecting the mechanical precision of the machine spindle is the structural thermal deformation under temperature variation. So, we focused on temperature variation investigate of spindle in experiment approach. A magnetic loading device has been used for the measurement, which have a more compact stator and shorter axis length. Meanwhile, the FEM 3D analysis of the compact magnetic loader has been presented. By using this contactless loader, the temperature variation when spindles are rotating under different loads have been monitored and recorded. Experiment results show that the radial load has increased the temperature of spindle, but the higher speed directly weakened this influence. Furthermore, this experiment approach is verified and proved to be suitable for spindle tests.

Paper-Based Magneto-Resistive Sensor: Modeling, Fabrication, Characterization, and Application

In this work, we developed and fabricated a paper-based anisotropic magneto-resistive sensor using a sputtered permalloy (Ni 81 Fe 19 ) thin film. To interpret the characteristics of the sensor, we proposed a computational model to capture the influence of the stochastic fiber network of the paper surface and to explain the physics behind the empirically observed difference in paper-based anisotropic magneto-resistance (AMR). Using the model, we verified two main empirical observations: (1) The stochastic fiber network of the paper substrate induces a shift of 45 ∘ in the AMR response of the paper-based Ni 81 Fe 19 thin film compared to a Ni 81 Fe 19 film on a smooth surface as long as the fibrous topography has not become buried. (2) The ratio of magnitudes of AMR peaks at different anisotropy angles and the inverted AMR peak at the 90 ∘ -anisotropy angle are explained through the superposition of the responses of Ni 81 Fe 19 inheriting the fibrous topography and smoother Ni 81 Fe 19 on buried fibrous topographies. As for the sensitivity and reproducibility of the sensor signal, we obtained a maximum AMR peak of 0 . 4 % , min-max sensitivity range of [ 0 . 17 , 0 . 26 ] % , average asymmetry of peak location of 2 . 7 kA m within two consecutive magnetic loading cycles, and a deviation of 250–850 A m of peak location across several anisotropy angles at a base resistance of ∼100 Ω . Last, we demonstrated the usability of the sensor in two educational application examples: a textbook clicker and interactive braille flashcards.