scholarly journals In Silico Study to Enhance Delivery Efficiency of Charged Nanoscale Nasal Spray Aerosols to the Olfactory Region Using External Magnetic Fields

2022 ◽  
Vol 9 (1) ◽  
pp. 40
Author(s):  
Benjamin Li ◽  
Yu Feng
Keyword(s):  
Magnetic Field ◽  
Drug Delivery ◽  
Magnetic Fields ◽  
Stokes Equations ◽  
Charged Particles ◽  
Injection Velocity ◽  
Aerodynamic Diameter ◽  
Nasal Drug Delivery ◽  
Velocity Magnitude ◽  
Delivery Efficiency

Various factors and challenges are involved in efficiently delivering drugs using nasal sprays to the olfactory region to treat central nervous system diseases. In this study, computational fluid dynamics was used to simulate nasal drug delivery to (1) examine effects on drug deposition when various external magnetic fields are applied to charged particles, (2) comprehensively study effects of multiple parameters (i.e., particle aerodynamic diameter; injection velocity magnitude, angle, and position; magnetic force strength and direction), and (3) determine how to achieve the optimal delivery efficiency to the olfactory epithelium. The Reynolds-averaged Navier–Stokes equations governed airflow, with a realistic inhalation waveform implemented at the nostrils. Particle trajectories were modeled using the one-way coupled Euler–Lagrange model. A current-carrying wire generated a magnetic field to apply force on charged particles and direct them to the olfactory region. Once drug particles reached the olfactory region, their diffusion through mucus to the epithelium was calculated analytically. Particle aerodynamic diameter, injection position, and magnetic field strength were found to be interconnected in their effects on delivery efficiency. Specific combinations of these parameters achieved over 65-fold higher drug delivery efficiency compared with uniform injections with no magnetic fields. The insight gained suggests how to integrate these factors to achieve the optimal efficiency.

scholarly journals The Magnetic Fields of Pulsars

1974 ◽  
Vol 64 ◽  
pp. 187-187
Author(s):  
D. M. Sedrakian
Keyword(s):  
Magnetic Field ◽  
Angular Velocity ◽  
Magnetic Fields ◽  
Relative Motion ◽  
Kinematic Viscosity ◽  
Charged Particles ◽  
Normal Fluid ◽  
Inertia Effects ◽  
Generation Mechanisms ◽  
Image Position

Two generation mechanisms of magnetic fields in pulsars are considered.If the temperature of a star is more than 108K, the star consists of a normal fluid of neutrons, protons and electrons. Because the angular velocity of pulsars is not constant dω/dt ≠0, inertia effects can occur, and generate magnetic fields through the relative motion of charged particles with different masses. The kinematic viscosity of electrons is 30 times larger than that of protons; hence electrons move with the crust, but the proton-neutron fluid will move relative to the electrons. The magnetic momentum can be calculated by the following formula where Meff = Mp + Mn(Nn/Np), R = radius of the star, σ = conductivity. For typical neutron stars we have dω/dt~ 10-8 s-2, R~106 cm, σ~1029 s-1 and we get a magnetic field of the order of 1010 G.

Targeting Magnetic Nanoparticles in High Magnetic Fields for Drug Delivery Purposes

2004 ◽  
Vol 820 ◽  
Author(s):  
Ramazan Asmatulu ◽  
Richard.O. Claus ◽  
Judy S. Riffle ◽  
Michael Zalich
Keyword(s):  
Magnetic Field ◽  
Drug Delivery ◽  
Magnetic Nanoparticles ◽  
Magnetic Fields ◽  
Magnetic Particles ◽  
Guidance System ◽  
Test Results ◽  
Test Parameters ◽  
Magnetic Guidance ◽  
The Magnetic Field

AbstractBiodegradable magnetic nanoparticles were synthesized using Poly(L-Lactic Acid) and magnetite nanoparticles (∼14 nm) at different dosages, and then these nanaoparticles (nanocomposites) and pure magnetic particles were targeted in external magnetic fields by changing the test parameters. The magnetic field test results showed that magnetic saturation, fluid speed, magnetic field distance and particle size were extremely effective for a magnetic guidance system that is needed for an effective drug delivery approach. Thus, it is assumed that such nanoparticles can carry drugs (chemotherapy) to be able to cure cancer tumors as well as many other diseases.

Numerical investigation of a plasma beam entering transverse magnetic fields

1989 ◽  
Vol 42 (1) ◽  
pp. 91-110 ◽  
Author(s):  
J. Koga ◽  
J. L. Geary ◽  
T. Fujinami ◽  
B. S. Newberger ◽  
T. Tajima ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Transverse Magnetic ◽  
Beam Momentum ◽  
Injection Velocity ◽  
Electron Mass ◽  
Particle In Cell ◽  
Plasma Beam ◽  
Beam Injection ◽  
The Magnetic Field

We study plasma-beam injection into transverse magnetic fields using both electrostatic and electromagnetic particle-in-cell (PIC) codes. In the case of small beam momentum or energy (low drift kinetic β) we study both large- and small-ion-gyroradius beams. Large-ion-gyroradius beams with a large dielectric constant ε ≫ (M/m)½ are found to propagate across the magnetic field via E × B drifts at nearly the initial injection velocity, where and M/m is the ion-to-electron mass ratio. Beam degradation and undulations are observed, in agreement with previous experimental and analytical results. When ε is of order (M/m)½ the plasma beam propagates across field lines at only half its initial velocity and loses its coherent structure. When ε is much less than (M/m)½ the beam particles decouple at the magnetic field boundary, scattering the electrons and slightly deflecting the ions. For small-ion-gyroradius beam injection a flute-type instability is observed at the beam-magnetic-field interface. In the case of large beam momentum or energy (high drift kinetic β) we observe good penetration of a plasma beam by shielding the magnetic field from the interior of the beam (diamagnetism). However, we observe anomalously fast penetration of the magnetic field into the beam and find that the diffusion rate depends on the electron gyroradius of the beam.

scholarly journals Guiding-centre transformation of the radiation–reaction force in a non-uniform magnetic field

2015 ◽  
Vol 81 (5) ◽  
Author(s):  
E. Hirvijoki ◽  
J. Decker ◽  
A. J. Brizard ◽  
O. Embréus
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Uniform Magnetic Field ◽  
Reaction Force ◽  
Charged Particles ◽  
Collision Operator ◽  
Radiation Reaction ◽  
Transform Method ◽  
Lie Transform ◽  
Radiation Reaction Force

In this paper, we present the guiding-centre transformation of the radiation–reaction force of a classical point charge travelling in a non-uniform magnetic field. The transformation is valid as long as the gyroradius of the charged particles is much smaller than the magnetic field non-uniformity length scale, so that the guiding-centre Lie-transform method is applicable. Elimination of the gyromotion time scale from the radiation–reaction force is obtained with the Poisson-bracket formalism originally introduced by Brizard (Phys. Plasmas, vol. 11, 2004, 4429–4438), where it was used to eliminate the fast gyromotion from the Fokker–Planck collision operator. The formalism presented here is applicable to the motion of charged particles in planetary magnetic fields as well as in magnetic confinement fusion plasmas, where the corresponding so-called synchrotron radiation can be detected. Applications of the guiding-centre radiation–reaction force include tracing of charged particle orbits in complex magnetic fields as well as the kinetic description of plasma when the loss of energy and momentum due to radiation plays an important role, e.g. for runaway-electron dynamics in tokamaks.

scholarly journals Janus microdimer swimming in an oscillating magnetic field

2020 ◽  
Vol 7 (12) ◽  
pp. 200378
Author(s):  
Jinyou Yang
Keyword(s):  
Magnetic Field ◽  
Drug Delivery ◽  
Magnetic Fields ◽  
Minimally Invasive ◽  
Environmental Remediation ◽  
Magnetic Torque ◽  
Link Type ◽  
Special Direction ◽  
Oscillating Magnetic Field

Artificial microswimmers powered by magnetic fields have numerous applications, such as drug delivery, biosensing for minimally invasive medicine and environmental remediation. Recently, a Janus microdimer surface walker that can be propelled by an oscillating magnetic field near a surface was reported by Li et al. ( Adv. Funct. Mater. 28 , 1706066. ( doi:10.1002/adfm.201706066 )). To clarify the mechanism for the surface walker, we numerically studied in detail a Janus microdimer swimming near a wall actuated by an oscillating magnetic field. The results showed that a Janus microdimer in an oscillating magnetic field can produce magnetic torque in the y -direction, which eventually propels the Janus microdimer along the x -direction near a wall. Furthermore, we found that the Janus microdimer can also move along a special direction in an oscillating magnetic field with two orientations without a wall. The knowledge obtained in this study is fundamental for understanding the interactions between a Janus microdimer and surfaces in an oscillating magnetic field and is useful for controlling Janus microdimer motion with or without a wall.

Analysis of Biological Effect of AC-DC Electromagnetic Fields using the Lorenz Model

2011 ◽  
pp. 31-53
Author(s):  
Malka N. Halgamuge ◽  
Chathurika D. Abeyrathne ◽  
Priyan Mendis
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Electric Field ◽  
Electromagnetic Fields ◽  
Biological Effect ◽  
Initial Velocity ◽  
Charged Particles ◽  
Initial Position ◽  
Dc Magnetic Field ◽  
Ac Electric Field

Electromagnetic fields (EMF) are essential to various applications directly involving humans. Fears about the biological effect of exposure to electromagnetic fields drive enormous research into this area. This research generates conflicting results, and consequently, uncertainty regarding possible health effects. This chapter studies a nonlinear Lorenz model describing interactions among charged particles and combined alternating (AC: alternating current) and static (DC: direct current) electromagnetic fields, for various combinations of frequencies, field strengths and relative angle (?) between the AC and DC magnetic fields. We investigate the effect on charged particles of three possible combinations of alternating and static electromagnetic fields: (i) AC electric field and DC magnetic field (ii) AC magnetic field and DC magnetic field (iii) AC electric field and AC and DC magnetic field. Then the behavior of the particle in these fields with different initial conditions and strong directional effects is observed when the angle between AC and DC magnetic fields is varied. The results show that the cyclotron resonance frequency is affected by charged particles’ initial position and initial velocity. Further, we observe strong effects of electric and magnetic fields on a charged particle in a biological cell with initial position and initial velocity.

A numerical study of a bubble pair rising side by side in external magnetic fields

2021 ◽  
Vol 926 ◽  
Author(s):  
Jie Zhang ◽  
Ming-Jiu Ni
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Lorentz Force ◽  
Stokes Equations ◽  
Numerical Study ◽  
Three Dimensional ◽  
Transverse Field ◽  
Asymmetric Distribution ◽  
Streamwise Vortices ◽  
Horizontal Magnetic Field

The motion of a pair of bubbles rising side by side under the influence of external magnetic fields is numerically examined. Through solving the fully three-dimensional Navier–Stokes equations, the results reveal that the bubble interactions are rather sensitive to the field direction and strength. At first, we identify that, in a hydrodynamic flow, whether the two bubbles will bounce or coalesce depends on the developments of the counter-rotating streamwise vortices during the collision. In particular, for an originally bouncing bubble pair, a streamwise magnetic field tends to promote their coalescence by weakening the strengths of the standing streamwise vortices, and such a weakening effect is caused by the asymmetric distribution of the Lorentz force in the presence of another bubble such that a torque is induced to offset the original streamwise vortices. Under a horizontal magnetic field, on the other hand, the influences are highly dependent on the angle between the bubble centroid line and the field: a transverse field or a moderate spanwise field always leads the bubble pair to coalescence while a strong spanwise field has the opposite effect. This anisotropic effect comes from the Lorentz force induced flow diffusion along the magnetic field, which not only produces two pairs of streamwise vortices at the bubble rear, but also homogenizes the pressure along the magnetic lines. As the competition between the two mechanisms varies with the magnetic direction and strength, the interaction between the bubble pair also changes. We show that the external magnetic fields control the bubble interaction through reconstructing the vortex structures, and hence the core mechanisms are identified.

Flow Control Using Alternating Magnetic Fields During Crystal Growth From a Melt

2012 ◽  
Author(s):  
Yue Huang ◽  
Kenneth E. Davis ◽  
Brent C. Houchens
Keyword(s):  
Magnetic Field ◽  
Crystal Growth ◽  
Magnetic Fields ◽  
Flow Control ◽  
Body Force ◽  
Stokes Equations ◽  
Magnetic Reynolds Number ◽  
Rotating Magnetic Field ◽  
Bandgap Energy ◽  
Alternating Magnetic Fields

Flow control during bulk melt crystal growth is desirable for producing ternary alloy semiconductors with tunable lattice parameters and bandgap energy, providing custom materials for specific electro-optical applications. Segregation between constituent elements in the melt, be it through preferential rejection at the growth front or density variations, limits the growth rate and the uniformity in the crystal. External alternating magnetic fields are employed to stir the electrically conducting melt. While mixing is desired, turbulent flow is generally not. Precise control is required to maintain a laminar melt flow while providing sufficient mixing. Stirring via a rotating magnetic field (RMF) and a three-coil traveling magnetic field (TMF) is modeled and compared for a cylindrical melt confined in an ampule. The RMF imposes a body force in the azimuthal direction while the TMF induces primarily radial and axial body forces. The magnetic fields are effectively decoupled from the flow fields due to the small magnetic Reynolds number. Therefore, the magnetic fields are first determined using a finite element solver. The flows are then solved by a spectral element model of the Navier-Stokes equations including an electromagnetic body force term.

The orbits of electrons and ions in the fields of the rotamak

1987 ◽  
Vol 37 (1) ◽  
pp. 1-13 ◽  
Author(s):  
W. N. Hugrass ◽  
M. Turley
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Charged Particles ◽  
The Self ◽  
Rotating Magnetic Field ◽  
Plasma Equilibrium ◽  
Rotating Magnetic Fields ◽  
Cylindrical Plasma ◽  
Electrons And Ions ◽  
Self Consistent

The motion of electrons and ions in the self-consistent fields of a compact toroidal equilibrium maintained by means of a rotating magnetic field is studied. It is found that the particles are confined although the lines of the instantaneous magnetic field are open. The results are compared with those obtained in an earlier study of the motion of charged particles in the self-consistent fields appropriate to cylindrical plasma equilibrium maintained by means of rotating magnetic fields.

Fractional dynamics of charged particles in magnetic fields

2016 ◽  
Vol 27 (08) ◽  
pp. 1650084 ◽  
Author(s):  
A. Coronel-Escamilla ◽  
J. F. Gómez-Aguilar ◽  
E. Alvarado-Méndez ◽  
G. V. Guerrero-Ramírez ◽  
R. F. Escobar-Jiménez
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Numerical Solutions ◽  
Charged Particles ◽  
Classical Case ◽  
Transverse Motion ◽  
Fractional Dynamics ◽  
Dissipative Effects ◽  
Relevant Role ◽  
Fractional Differential

In many physical applications the electrons play a relevant role. For example, when a beam of electrons accelerated to relativistic velocities is used as an active medium to generate Free Electron Lasers (FEL), the electrons are bound to atoms, but move freely in a magnetic field. The relaxation time, longitudinal effects and transverse variations of the optical field are parameters that play an important role in the efficiency of this laser. The electron dynamics in a magnetic field is a means of radiation source for coupling to the electric field. The transverse motion of the electrons leads to either gain or loss energy from or to the field, depending on the position of the particle regarding the phase of the external radiation field. Due to the importance to know with great certainty the displacement of charged particles in a magnetic field, in this work we study the fractional dynamics of charged particles in magnetic fields. Newton’s second law is considered and the order of the fractional differential equation is [Formula: see text]. Based on the Grünwald–Letnikov (GL) definition, the discretization of fractional differential equations is reported to get numerical simulations. Comparison between the numerical solutions obtained on Euler’s numerical method for the classical case and the GL definition in the fractional approach proves the good performance of the numerical scheme applied. Three application examples are shown: constant magnetic field, ramp magnetic field and harmonic magnetic field. In the first example the results obtained show bistability. Dissipative effects are observed in the system and the standard dynamic is recovered when the order of the fractional derivative is 1.

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