ANALISA PENGARUH GAYA ELEKTROSTATIK  PADA SPEKTRUM PENCITRAAN RESONANSI  MAGNETIK (MRI) DALAM JARINGAN BIOLOGI

A study of magnetic core resonance imaging modeling of biological tissue has been carried out in analyzing the effect of electrostatic forces with computational approach. This analysis aims to look at the effect of electric and magnetic force on the spectrum of breast cancer tissue. Physical parameters were determined using the modeled wave equation with the application of mathematical wolfram software 9. Computational or modeling results obtained 6 variations of the MRI spectrum showing the peak magnitude of the electric and magnetic spectrum changes by varying the resolution and distance. This is evidenced from the maximum resolution range ie the peak of the electric field spectrum at amplitude 25 a.u is at a concentration of 5 ppm. Resolution of spectrum peak medium is at concentration of 3-4 ppm whereas minimum resolution has 4 peak spectrum that is at concentration 1-2 ppm, 2-3ppm, 3-4ppm and 4ppm. the result of MRI spektrum for distance variation resulted in spectrum change, further reduced the distance then the mri spectrum in magnetic and electric field approaching spin 1.

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A Computational Approach Toward Identification of Malignant Lesions of the Human Breast: The Dynamics of Magnetic Resonance Imaging Contrast Agent Uptake

10.21236/ada394210 ◽

2000 ◽

Author(s):

Jonathan H. Kaufman ◽

John S. Leigh

Keyword(s):

Magnetic Resonance Imaging ◽

Magnetic Resonance ◽

Contrast Agent ◽

Computational Approach ◽

Human Breast ◽

Resonance Imaging ◽

Magnetic Resonance Imaging Contrast ◽

Malignant Lesions ◽

Imaging Contrast Agent

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Factors Controlling Electropermeabilisation of Cell Membranes

Technology in Cancer Research & Treatment ◽

10.1177/153303460200100502 ◽

2002 ◽

Vol 1 (5) ◽

pp. 319-327 ◽

Cited By ~ 8

Author(s):

M. P. Rols ◽

M. Golzio ◽

B. Gabriel ◽

J. Teissié

Keyword(s):

Cell Surface ◽

Electric Field ◽

Pulse Duration ◽

Cell Membranes ◽

Physical Parameters ◽

Local Exchange ◽

Physical Mechanisms ◽

A Cell

Electric field pulses are a new approach for drug and gene delivery for cancer therapy. They induce a localized structural alteration of cell membranes. The associated physical mechanisms are well explained and can be safely controlled. A position dependent modulation of the membrane potential difference is induced when an electric field is applied to a cell. Electric field pulses with an overcritical intensity evoke a local membrane alteration. A free exchange of hydrophilic low molecular weight molecules takes place across the membrane. A leakage of cytosolic metabolites and a loading of polar drugs into the cytoplasm are obtained. The fraction of the cell surface which is competent for exchange is a function of the field intensity. The level of local exchange is strongly controlled by the pulse duration and the number of successive pulses. The permeabilised state is long lived. Its lifetime is under the control of the cumulated pulse duration. Cell viability can be preserved. Gene transfer is obtained but its mechanism is not a free diffusion. Plasmids are electrophoretically accumulated against the permeabilised cell surface and form aggregates due to the field effect. After the pulses, several steps follow: translocation to the cytoplasm, traffic to the nucleus and expression. Molecular structural and metabolic changes in cells remain mostly poorly understood. Nevertheless, while most studies were established on cells in culture ( in vitro), recent experiments show that similar effects are obtained on tissue ( in vivo). Transfer remains controlled by the physical parameters of the electrical treatment.

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Numerical study of electric field effects on the deformation of two-dimensional liquid drops in simple shear flow at arbitrary Reynolds number

Journal of Fluid Mechanics ◽

10.1017/s0022112009006442 ◽

2009 ◽

Vol 626 ◽

pp. 367-393 ◽

Cited By ~ 32

Author(s):

STEFAN MÄHLMANN ◽

DEMETRIOS T. PAPAGEORGIOU

Keyword(s):

Steady State ◽

Shear Flow ◽

Electric Field ◽

Electric Fields ◽

Simple Shear ◽

Simple Shear Flow ◽

Physical Parameters ◽

Shear Stresses ◽

Two Dimensional ◽

Liquid Drops

The effect of an electric field on a periodic array of two-dimensional liquid drops suspended in simple shear flow is studied numerically. The shear is produced by moving the parallel walls of the channel containing the fluids at equal speeds but in opposite directions and an electric field is generated by imposing a constant voltage difference across the channel walls. The level set method is adapted to electrohydrodynamics problems that include a background flow in order to compute the effects of permittivity and conductivity differences between the two phases on the dynamics and drop configurations. The electric field introduces additional interfacial stresses at the drop interface and we perform extensive computations to assess the combined effects of electric fields, surface tension and inertia. Our computations for perfect dielectric systems indicate that the electric field increases the drop deformation to generate elongated drops at steady state, and at the same time alters the drop orientation by increasing alignment with the vertical, which is the direction of the underlying electric field. These phenomena are observed for a range of values of Reynolds and capillary numbers. Computations using the leaky dielectric model also indicate that for certain combinations of electric properties the drop can undergo enhanced alignment with the vertical or the horizontal, as compared to perfect dielectric systems. For cases of enhanced elongation and alignment with the vertical, the flow positions the droplets closer to the channel walls where they cause larger wall shear stresses. We also establish that a sufficiently strong electric field can be used to destabilize the flow in the sense that steady-state droplets that can exist in its absence for a set of physical parameters, become increasingly and indefinitely elongated until additional mechanisms can lead to rupture. It is suggested that electric fields can be used to enhance such phenomena.

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Induced electronic phenomena in crystals of p-GaSe semiconductor promising for optoelectronics

Journal of Physics Conference Series ◽

10.1088/1742-6596/2103/1/012179 ◽

2021 ◽

Vol 2103 (1) ◽

pp. 012179

Author(s):

R F Babayeva

Keyword(s):

Electric Field ◽

High Resistance ◽

Dark Current ◽

Qualitative Explanation ◽

Maximum Value ◽

Spectrum Change ◽

Erbium Doped ◽

Impurity Photoconductivity ◽

Low Illumination ◽

Field Strengths

Abstract An induced impurity photoconductivity by the electric field, thermally stimulated conductivity and spontaneous pulsations of the dark current were found in the undoped (with a dark resistivity P77≈3•104÷108 Ω-cm at T≈77 K) and erbium doped (NEr=10–5÷10–1 at.%) p-GaSe crystals in the temperature range of T≤240÷250 K at electric field strengths (E) creating a noticeable injection. It was found that the value of the observed impurity photoconductivity (M) monotonically increase at low illumination in undoped crystals with increasing P77 and its spectrum smoothly expands towards longer waves. The value of ∆ii and the width of its spectrum change non-monotonically with increasing NEr in doped crystal and it gets its maximum value at NEr ≈5•10-4 at.%. The intensity of spontaneous pulsations increases with increasing E at the higher electric field strengths. However, the impurity photoconductivity and the peak of thermally stimulated conductivity gradually disappeared. The amplitude and frequency of the observed spontaneous pulsations of the dark current is increased with increasing in the injection ability of the contacts. Moreover, the pulsations of the dark current gradually disappeared with increasing T. It was shown that all these three phenomena are directly caused by the recharge of sticking levels with a depth Er ≈+0.42 eV and a density Nt≈ 1015 cm-3 by injected holes. However, in high-resistance undoped and doped Er ≤10-2 at.% crystals, it is also necessary to consider the presence of random macroscopic defects in the samples to explain their features. A qualitative explanation is proposed based on the obtained results.

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KAJIAN KOMPUTASI POLA GELOMBANG RESONANSI MAGNET INTI (NMR) DENGAN TRANSFORMASI FOURIER

Komunikasi Fisika Indonesia ◽

10.31258/jkfi.15.1.17-22 ◽

2018 ◽

Vol 15 (1) ◽

pp. 17

Author(s):

Faprilia Khusnul ◽

Salomo Salomo ◽

Muhammad Hamdi

Keyword(s):

Reference Data ◽

Wave Pattern ◽

Computational Approach ◽

Physical Parameters ◽

Mathematical Software ◽

Transformation Equation ◽

Nuclear Spins ◽

J Coupling ◽

Research Standards ◽

J 24

Research on nuclear magnetic resonance (NMR) modeling has been done with computational approach. This study aims to determine the shape of signals and spectra of some of the combined nuclear spins. The physical parameters were determined using Fourier transformation equation modeled with the wolfram mathematical software 9.0. The relaxation time of the 1/2 nuclear spin was varied according to the nuclear state of cancer tissue.This produces a cosine wave pattern for the signal at T2 = 0.11 ms. Variations of this in chemical shift (Δ) and J-coupling (J) for modeling were performed in 9 times. The spectrum of one spin is generated at the value of Δ = 0.001 Hz and J = 0 Hz, the spectrum of two spins at Δ = 849,001 Hz and J = 24 Hz. These results can be applied to research interests for the medical world and as reference data for research standards.

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Effect of Contaminant Flow-rate and Applied Voltage on the Current Density and Electric Field of Polymer Tracking Test

International Journal of Electrical and Computer Engineering (IJECE) ◽

10.11591/ijece.v6i2.9517 ◽

2016 ◽

Vol 6 (2) ◽

pp. 819

Author(s):

F. L. Muhamedin ◽

M. A. M. Piah ◽

N. A. Othman ◽

Nasir Ahmed Algeelani

Keyword(s):

Electric Field ◽

Flow Rate ◽

Current Density ◽

Applied Voltage ◽

Fem Simulation ◽

Surface Discharge ◽

Physical Parameters ◽

Insulation Material ◽

Material Degradation ◽

Contaminant Flow

<p>Electrical failure due to surface discharge on the insulation material will cause material degradation and eventually lead to system failure. The flow of leakage current (LC) on the insulator surface under wet contamination is used to determine the material degradation level. According to IEC 60587 standard, LC exceeding 60 mA for more than two seconds is considered as failure. In this study, the electric field and current density distributions on the linear low-density polyethylene (LLDPE) and natural rubber blend material have been analyzed using finite element method (FEM) analysis. The physical parameters used in FEM simulation were applied with voltage and contaminant flow rate, in accordance to contaminant conductivity. Tracking test condition according to IEC 60587 standard has been applied as proposed by the reference work in simulation using QuickField FEM software. The results show that the electric field and current density would become critical in higher applied voltage and contaminant flow rate. The highest average and highest maximum current density and electric field are found in both applied voltage of 6 kV and contaminant flow rate of 0.90 mlmin<sup>-1</sup>.</p>

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Charged perfect fluid stellar structures with Bardeen model

International Journal of Modern Physics A ◽

10.1142/s0217751x20500839 ◽

2020 ◽

Vol 35 (18) ◽

pp. 2050083 ◽

Cited By ~ 1

Author(s):

M. Farasat Shamir ◽

G. Mustafa ◽

Quresha Hanif

Keyword(s):

Electric Field ◽

Perfect Fluid ◽

Maxwell Equations ◽

Graphical Analysis ◽

Physical Parameters ◽

Symmetric Model ◽

Speed Of Light ◽

Suitable Form ◽

Model Geometry ◽

Spherically Symmetric Model

This paper is devoted to study static spherically symmetric model in the presence of charged perfect fluid. This is the generalization of neutral perfect fluid (when there is no charge) through the solution of Einstein Maxwell equations. For this purpose, we consider a suitable form of gravitational potential [Formula: see text] and the electric field [Formula: see text], already used in the literature. The value of mass-radius ratio or compactness [Formula: see text], which depends upon the chosen model exceeds the value [Formula: see text] corresponding to neutral stars. The most important feature of the current study is to use the Bardeen model geometry instead of usual Reissner–Nordström model for the matching conditions. In this case the energy density and pressure remain positive, bounded and monotonically decreasing whereas electric field is monotonically increasing. Also the causality condition, i.e. the magnitude of speed of sound must be less than the speed of light, is satisfied. Moreover, the behavior of all the physical parameters at the center and on surface of star of mass [Formula: see text] and for Her X-1 are tabulated. All the results by graphical analysis and tabular information suggest that Bardeen model provides physically realistic stellar structures.

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ON GRAVITATIONALLY AND ELECTRODYNAMICALLY BOUND NUCLEAR MATTER CORES OF STELLAR DIMENSIONS

International Journal of Modern Physics D ◽

10.1142/s0218271811019918 ◽

2011 ◽

Vol 20 (10) ◽

pp. 1995-2002 ◽

Cited By ~ 8

Author(s):

MICHAEL ROTONDO ◽

REMO RUFFINI ◽

SHE-SHENG XUE ◽

VLADIMIR POPOV

Keyword(s):

Electric Field ◽

Nuclear Matter ◽

Analytic Solutions ◽

Physical Parameters ◽

Heavy Nuclei ◽

Neutral Atoms ◽

Charge Neutrality ◽

Thomas Fermi ◽

Surface Energies ◽

The Stability

In a unified treatment we extrapolate results for neutral atoms with heavy nuclei to nuclear matter cores of stellar dimensions with mass numbers A ≈ (m Planck /mn)3 ~ 1057. We give explicit analytic solutions for the relativistic Thomas–Fermi equation of Nn neutrons, Np protons and Ne electrons in beta equilibrium, fulfilling global charge neutrality, with Np = Ne. We give explicit expressions for the physical parameters including the Coulomb and the surface energies and we study as well the stability of such configurations. Analogous to heavy nuclei these macroscopic cores exhibit an overcritical electric field near their surface.

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