Crystallisation in a two-dimensional granular system at constant temperature

We study the crystallisation processes occurring in a nonvibrating two-dimensional magnetic granular system at various fixed values of the effective temperature. In this system, the energy loss due to dissipative effects is compensated by the continuous energy input coming into the system from a sinusoidal magnetic field. When this balance leads to high values of the effective temperature, no aggregates are formed, because particles’ kinetic energy prevents them from aggregating. For lower effective temperatures, formation of small aggregates is observed. The smaller the values of the applied field’s amplitude, the larger the number of these disordered aggregates. One also observes that when clusters form at a given effective temperature, the average effective diffusion coefficient decreases as time increases. For medium values of the effective temperature, formation of small crystals is observed. We find that the sixth bond-orientational order parameter and the number of bonds, when considering more than two, are very sensitive for exhibiting the order in the system, even when crystals are still very small.

Design of a New 1D Halbach Magnet Array with Good Sinusoidal Magnetic Field by Analyzing the Curved Surface

In the linear and planar motors, the 1D Halbach magnet array is extensively used. The sinusoidal property of the magnetic field deteriorates by analyzing the magnetic field at a small air gap. Therefore, a new 1D Halbach magnet array is proposed, in which the permanent magnet with a curved surface is applied. Based on the superposition of principle and Fourier series, the magnetic flux density distribution is derived. The optimized curved surface is obtained and fitted by a polynomial. The sinusoidal magnetic field is verified by comparing it with the magnetic flux density of the finite element model. Through the analysis of different dimensions of the permanent magnet array, the optimization result has good applicability. The force ripple can be significantly reduced by the new magnet array. The effect on the mass and air gap is investigated compared with a conventional magnet array with rectangular permanent magnets. In conclusion, the new magnet array design has the scalability to be extended to various sizes of motor and is especially suitable for small air gap applications.

Влияние низкочастотного магнитного поля на полиэлектролитные микрокапсулы с наночастицами магнетита

Polyelectrolyte microcapsules have been prepared by sequential adsorption of oppositely charged sodium polystyrene sulfonate and polyallylamine hydrochloride molecules on the surface of calcium carbonate particles. The capsule shells are functionalized with Fe3O4 magnetic nanoparticles to provide control over the localization of microcapsules and the permeability of their shells. The control of microcapsule permeability using a low-frequency non-heating magnetic field is based on the magneto-mechanical actuation, which, due to its high penetration ability, locality and safety, is preferable for application in vivo to magnetic hyperthermia. Here we report on the results of analysis of the effect of a low-frequency pulsed sinusoidal magnetic field with a frequency of 50 Hz on the permeability of the microcapsule shell for fluorescently labeled dextran molecules. It was found that the permeability of the shell increases with a decrease in the duration of the pause between magnetic field pulses, causing an increase in the amount of dextran in the shell.

Time-like detonation in presence of magnetic field

We study the effect of magnetic field in an implosion process achieved by radiation. A time-varying sinusoidal magnetic field is seen to affect the continuous transition of space-like detonation to time-like detonation at the core of implosion region. The oscillating varying magnetic field has a significant effect in increasing the volume of the time-like detonation of the core of implosion and also modifies the time of the implosion process. This transition can have significant outcome both theoretically and experimentally in the areas of high-energy hadronization of quark–gluon plasma matter and inertial confinement fusion efforts of fuels.

Beneficial effects of Extremely Low Frequency (ELF) Sinusoidal magnetic field (SMF) exposure on mineral and protein content of mungbean seeds and sprout.

ive mungbean [Vigna radiata (L.) Wilczek] lines (CN9-5, EC693363, Harsha, KPS-1 and NM 94) were subjected to three different Extremely Low Frequency (ELF) sinusoidal magnetic field (SMF) treatments. Fresh seed lots were exposed to ELF-SMF for 5 hours/day for a total duration of 15 days. Three treatment combinations of ELF-SMF chosen for assessment and comparison were: T1-10Hz, 1500 + 250 nanoTesla (nT), T2- 50Hz, 1500 + 250nT and T3 - 100Hz, 1500 + 250nT. Non-treated seeds were maintained as control (T4). Minerals (iron, calcium, zinc and total phosphorus) and protein contents were determined in both the control and test seed lots and sprout samples raised from them. The sprouting parameters were also recorded. All three ELF-SMF treatments were significant for calcium and total phosphorus content in the test seed samples when compared to control. In the case of sprouts, with respect to minerals, all the ELF-SMF treatments were significant for calcium content when compared to control. With respect to protein, sprouts from EC 693363 line recorded 8.3% increase in protein content in T1 (10Hz) while sprouts from Harsha line recorded 7.2% increase in protein content in T2 (50Hz) compared to their respective controls. No treatment effects were observed for the sprouting parameters

Discovery of a Unique Sinusoidal Frequency for the Effective Magnetic Treatment of Brackish Water

Magnetic treatment of aqueous solutions containing dissolved CaCO3is known to affect its precipitation exerted by heating or raising the pH of the solution. In this work, experiments have been performed on two kinds of water: (a) a simulated water containing only CaCO3as dissolved salt and (b) a real brackish water sample of high total hardness from an industrial area containing a wide range of impurity salts. It has been discovered for the first time that using a sinusoidal magnetic field, treatment at a frequency of ca. 150 kHz (for a range of 0–1000 kHz) results in the maximum calcite precipitation independent of the initial water composition. The discovered phenomenon could be explained based on the resonance taking place due to the synchronization of the induced magnetic field with the proton exchange rate of water molecules.

Effect of 50-Hz Sinusoidal Magnetic Field on the Production of Superoxide Anion and the Expression of Heat-shock Protein 70 in RAW264 Cells

There is a growing concern if the power-line frequency (50/60 Hz) magnetic field (termed in this paper ELF-MF) increases cancer risks. Since one of the major causes of cancer is cellular oxidative stress, whether the ELF-MF increases the oxidative stress is a central problem in the studies on the biological effect of the ELF-MF. Here, we have investigated the effect of 50-Hz sinusoidal magnetic field on the production of O2-, the expression of heat shock protein (HSP) 70 and the mitochondrial membrane potential in cell line macrophage RAW264 cells. Macrophages were exposed to or not exposed to 0.1-mT or 0.5-mT, 50-Hz sinusoidal magnetic field and were subjected to (1) assay for O2- (2) analysis of the expression of HSP70, and (3) measurement of the mitochondrial membrane potential with a fluorescent indicator. The 50-Hz magnetic field enhanced production of O2- and the expression of HSP70, both of which are consistent with previous studies. The exposure to 50-Hz magnetic field decreased mitochondrial membrane potential indicating the diminished activity of mitochondria. The uncoupler of mitochondrial function, carbonyl cyanide p-trifluoromethoxyphenylhydrazone diminished the membrane potential, as expected. On the other hand, it increased the production of O2-. The results collectively suggest that the 50-Hz magnetic field diminished the mitochondrial membrane potential, which led to the increase in the production of O2- and the expression of HSP70 protein.

Concept of Phase Cycling in Pulsed Magnetic Resonance Using Sinusoidal Magnetic Field Modulation

In conventional pulsed magnetic resonance suppression of unwanted signals is achieved by changing pulse phases with respect to the reference signal and spin magnetization phase. This method is called phase cycling. An alternative approach is suggested to separate the unwanted signals from the spin echo by using magnetic field modulation. Precession frequency of the spins, and therefore phases of free indication decays and echo signals, can be controlled by the selection of modulation parameters. This enables phase cycling. Since the signal is detected in the presence of the changing magnetic field, which drives spin precession, the echo signal is frequency-modulated. Numerical transformation into an accelerating reference frame associated with the Larmor frequency restores the signal to a form that would have been observed in the absence of modulation. The suggested phase cycling method is analyzed in detail for the two pulse spin echo case.