The Fundamentals of Electrostatic Spinning

1977 ◽  
Vol 47 (12) ◽  
pp. 780-789 ◽  
Author(s):  
Ismail Doĝu
Keyword(s):  
Field Strength ◽  
Electrostatic Field ◽  
Dielectric Breakdown ◽  
Mathematical Treatment ◽  
Lateral Vibration ◽  
Textile Fiber ◽  
Electrostatic Spinning ◽  
Spinning Process ◽  
Freely Suspended ◽  
Field Strengths

A mathematical analysis of uncrimping of textile fibers in an electrostatic field is given. One important result of this analysis is that a textile fiber is very little uncrimped in the field strengths that can possibly be used in this process, since higher field strengths cause a dielectric breakdown. A mathematical treatment of the orientation of fibers in an electrostatic field is also given. The amount of orientation depending on the fiber physical properties and process parameters are calculated. It is shown that a freely-suspended single fiber moving in an electrostatic field may perform either a periodic or nonperiodic lateral vibration depending on the magnitude of the electrostatic field strength. It is shown that in an electrostatic spinning process there is little fiber orientation in the time available before the fiber enters into the rotor-electrode. The critical value of the field strength determining whether a fiber will perform a periodic or nonperiodic movement is calculated. It is shown that the transfer of fibers of variable fineness by means of an electrostatic field from the feeding device to the twisting element is a randomizing process of the positions of fibers relative to each other, and this is rather important as far as the yarn evenness is concerned.

The Research on Optimization of Electrostatic Field for High Voltage Electrostatic Spinning Machine

2013 ◽  
Vol 694-697 ◽  
pp. 2938-2941
Author(s):  
Chang Jie Liu ◽  
Jing Zhang ◽  
Ye Dai
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Electrostatic Field ◽  
Fibrous Material ◽  
Static Electric Field ◽  
Element Analysis ◽  
Solution Flow ◽  
Electrostatic Spinning ◽  
Nano Fiber ◽  
Spinning Process

One of the most important way to get nano fiber is electrostatic spinning technology. Electrostatic spinning process can be descripte that polymer solution flow in the strong static electric field. When solvent has be solidificated, Fibrous material is get. All the electrostatic spinning devices are test machines. So it is necessary to finish finite element analysis and optimization of strong static electric working field.

scholarly journals Investigation of the cosmic ray population and magnetic field strength in the halo of NGC 891

2018 ◽  
Vol 615 ◽  
pp. A98 ◽  
Author(s):  
D. D. Mulcahy ◽  
A. Horneffer ◽  
R. Beck ◽  
M. Krause ◽  
P. Schmidt ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Magnetic Field Strength ◽  
Low Frequency ◽  
Cosmic Ray ◽  
Radio Continuum ◽  
Continuum Emission ◽  
Low Frequencies ◽  
Very Large Array ◽  
Field Strengths

Context. Cosmic rays and magnetic fields play an important role for the formation and dynamics of gaseous halos of galaxies. Aims. Low-frequency radio continuum observations of edge-on galaxies are ideal to study cosmic-ray electrons (CREs) in halos via radio synchrotron emission and to measure magnetic field strengths. Spectral information can be used to test models of CRE propagation. Free–free absorption by ionized gas at low frequencies allows us to investigate the properties of the warm ionized medium in the disk. Methods. We obtained new observations of the edge-on spiral galaxy NGC 891 at 129–163 MHz with the LOw Frequency ARray (LOFAR) and at 13–18 GHz with the Arcminute Microkelvin Imager (AMI) and combine them with recent high-resolution Very Large Array (VLA) observations at 1–2 GHz, enabling us to study the radio continuum emission over two orders of magnitude in frequency. Results. The spectrum of the integrated nonthermal flux density can be fitted by a power law with a spectral steepening towards higher frequencies or by a curved polynomial. Spectral flattening at low frequencies due to free–free absorption is detected in star-forming regions of the disk. The mean magnetic field strength in the halo is 7 ± 2 μG. The scale heights of the nonthermal halo emission at 146 MHz are larger than those at 1.5 GHz everywhere, with a mean ratio of 1.7 ± 0.3, indicating that spectral ageing of CREs is important and that diffusive propagation dominates. The halo scale heights at 146 MHz decrease with increasing magnetic field strengths which is a signature of dominating synchrotron losses of CREs. On the other hand, the spectral index between 146 MHz and 1.5 GHz linearly steepens from the disk to the halo, indicating that advection rather than diffusion is the dominating CRE transport process. This issue calls for refined modelling of CRE propagation. Conclusions. Free–free absorption is probably important at and below about 150 MHz in the disks of edge-on galaxies. To reliably separate the thermal and nonthermal emission components, to investigate spectral steepening due to CRE energy losses, and to measure magnetic field strengths in the disk and halo, wide frequency coverage and high spatial resolution are indispensable.

A 4 × 4 array multichannel magnetic stimulation system using submillimeter sized planar square spiral coils: The spatial distribution of electromagnetic field

2022 ◽  
pp. 1-18
Author(s):  
Lei Tian ◽  
Limei Song ◽  
Yu Zheng ◽  
Jinhai Wang
Keyword(s):  
Magnetic Field ◽  
Electromagnetic Field ◽  
Spatial Distribution ◽  
Field Strength ◽  
Electric Field ◽  
Magnetic Stimulation ◽  
Spiral Coil ◽  
Average Magnetic Field ◽  
Stimulation System ◽  
Field Strengths

Multi-coil magnetic stimulation has advantages over single-coil magnetic stimulation, such as more accurate targeting and larger stimulation range. In this paper, a 4 × 4 array multichannel magnetic stimulation system based on a submillimeter planar square spiral coil is proposed. The effects of multiple currents with different directions on the electromagnetic field strength and the focusing zone of the array-structured magnetic stimulation system are studied. The spatial distribution characteristics of the electromagnetic field are discussed. In addition, a method is proposed that can predict the spatial distributions of the electric and magnetic fields when currents in different directions are applied to the array-structured magnetic stimulation system. The study results show that in the section of z = 2 μm, the maximum and average magnetic field strengths of the array-structured magnetic stimulation system are 6.39 mT and 2.68 mT, respectively. The maximum and average electric field strengths are 614.7 mV/m and 122.82 mV/m, respectively, where 84.39% of the measured electric field values are greater than 73 mV/m. The average magnetic field strength of the focusing zone, i.e., the zone in between the two coils, is 3.38 mT with a mean square deviation of 0.18. Therefore, the array-structured multi-channel magnetic stimulation system based on a planar square spiral coil can have a small size of 412 μm × 412 μm × 1.7 μm, which helps improving the spatial distribution of electromagnetic field and increase the effectiveness of magnetic stimulation. The main contribution of this paper is a method for designing multichannel micro-magnetic stimulation devices.

Effect of electromagnetic field on germination of groundnut seeds (Arachis hypogaea L)

2012 ◽  
Vol 2 (2) ◽  
pp. 73-78
Author(s):  
E. Rajasekhar ◽  
R. Jeevan Kumar ◽  
C. M. Subhan ◽  
P. Panduranga ◽  
T. Krishnamurthy
Keyword(s):  
Electromagnetic Field ◽  
Relative Humidity ◽  
Field Strength ◽  
Arachis Hypogaea ◽  
Exposure Time ◽  
Room Temperature ◽  
Total Weight ◽  
South Pole ◽  
Arachis Hypogaea L ◽  
Field Strengths

Present work is about the influence of Electromagnetic field [EMF] treatment on the improvement of groundnut seeds (Arachis hypogaea L) germination. The treatment consisted of different electromagnetic field strengths 2, 4, 7 and 10 milli Tesla [mT] in different exposure times 10, 20, 30 and 40 min. In every measurement, the relative humidity and room temperature were recorded. The germination [G] of seed in terms of percentage [% ], the stems length [SL] and roots length [RL] in millimeter [mm] at 6th day and 12th day after experiment, and the total weight [TW] in milligram at 12th day have been measured. Best results have been obtained for variants with exposure time of 30 min and field strength of 7 mT at south pole. Result obtained in the present investigation revealed that the energy absorbed by molecules was high at lower output strength and shorter exposure time improved biologicalfunctions, stimulation effect could be achieved.

scholarly journals Programmable shunt valve interactions with osseointegrated hearing devices

2017 ◽  
Vol 19 (4) ◽  
pp. 384-390
Author(s):  
Matthew J. Pierson ◽  
Daniel Wehrmann ◽  
J. Andrew Albers ◽  
Najib E. El Tecle ◽  
Dary Costa ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Magnetic Field Strength ◽  
Shunt Valve ◽  
Vp Shunt ◽  
Magnetic Attachment ◽  
Hearing Devices ◽  
Programmable Valves ◽  
The Magnetic Field ◽  
Field Strengths

OBJECTIVE Patients with ventriculoperitoneal (VP) shunts with programmable valves who would benefit from osseointegrated hearing devices (OIHDs) represent a unique population. The aim of this study was to evaluate the magnetic field strengths of 4 OIHDs and their interactions with 5 programmable VP shunt valves. METHODS Magnetic field strength was measured as a function of distance for each hearing device (Cochlear Baha 5, Cochlear Baha BP110, Oticon Ponto Plus Power, and Medtronic Sophono) in the following modes: inactive, active in quiet, and active in 60 decibels of background noise in the sound booth. The hearing devices were introduced to each shunt valve (Aesculap proGAV, Aesculap proGAV 2.0, Codman Hakim, Codman Certas, and Medtronic Strata II) also as a function of distance in these identical 3 settings. Each trial was repeated 5 times. Between each trial, the valves were assessed for a change in setting. Finally, using a skull model, the devices were introduced to each other in standard anatomical locations and the valves were assessed for a change in settings. RESULTS The maximum magnetic field strengths generated by the Cochlear Baha 5, BP110, and Oticon OIHDs were 1.1, 36.2, and 48.7 gauss (G), respectively. The maximum strength generated by the Sophono device was > 800 G. The magnetic field strength of the hearing devices decreased markedly with increasing distance from the device. The strength of the Sophono's magnetic attachment decreased to 34.8 G at 5 mm. The Codman Hakim, Codman Certas, and Medtronic Strata II valve settings changed when rotating the valves next to the Sophono abutment. No other changes in valve settings occurred in the distance or anatomical models for any other trials. CONCLUSIONS This is the first study evaluating the interaction between OIHDs and programmable VP shunt valves. The findings suggest that it is safe to use these devices together without having to switch to a nonprogrammable valve or move the shunt valve to a more distant location. Still, care should be taken if the Sophono device is used to ensure that the valve is ≥ 5 mm away from the magnetic attachment.

Improving electrospinning process by numerical analysis of 3-D computer models

2019 ◽  
Vol 38 (4) ◽  
pp. 1098-1110
Author(s):  
Anna Firych-Nowacka ◽  
Krzysztof Smolka ◽  
Sławomir Wiak
Keyword(s):  
Field Strength ◽  
Electric Field ◽  
Field Intensity ◽  
Electrostatic Field ◽  
Electric Field Intensity ◽  
Computer Models ◽  
Electrospinning Process ◽  
Strength Analysis ◽  
Original Solution ◽  
Content Type

Purpose Electrospinning is a method of the polymer super thin fibres formation by the electrostatic field. The distribution of electrostatic field affects the effectiveness of the electrospinning. Design/methodology/approach This paper presents various computer models that can improve the electrospinning process. The possibilities of modelling the electrostatic field in the design of electrospinning equipment are presented. Findings In the research part, the one focussed on finding a cylinder-shaped collector structure to limit the adverse effect of an uneven distribution of the electric field intensity on the collector. Originality/value The paper concerns the improvement of the electrospinning process with the use of electrostatic field modelling. In the first part, several possible applications of electrostatic models have been indicated, thanks to which the efficiency of the process has been improved. The original solution of the collector geometry was presented, which according to the authors, in comparison with previous models, gives the most promising results. In this solution, it was possible to obtain an even distribution of the electric field intensity while removing the unfavourable effect of the field strength increase on the outer edges of the collector. The most important aspect in this paper is electric field strength analysis.

CHARACTERISATION OF THE COMPLEX SHEAR MODULUS PROPERTIES OF ELECTRO-RHEOLOGICAL FLUIDS BY THE DIRECT STIFFNESS AND MASTER CURVE TECHNIQUES

1996 ◽  
Vol 10 (23n24) ◽  
pp. 3227-3236 ◽  
Author(s):  
S O Oyadiji
Keyword(s):  
Field Strength ◽  
Shear Modulus ◽  
Electric Field ◽  
Electric Field Strength ◽  
Loss Factor ◽  
Master Curve ◽  
Measured Temperature ◽  
Direct Stiffness ◽  
Er Fluid ◽  
Field Strengths

The direct stiffness technique was employed to characterise the complex modulus properties of a silicone oil-based electrorheological fluid over a frequency range from 30Hz to 300Hz and a temperature range from 0°C to 60ºC. The ER fluid device utilised was a set of concentric cylinders possessing a radial gap of 3mm between adjacent cylinders. Electric field strengths of between 0kV/mm and 2kV/mm were applied across the ER fluid. The results show that the shear modulus of the ER fluid decreased monotonically as the temperature was increased from 0ºC to 60ºC. Overall, the shear modulus decreased by a factor of up to 20. On the other hand, the shear loss factor increased from a low value of about 0.05 at 0ºC to a high value of about 1.0 at 60ºC. Conversely, as the electric field strength was increased from 0kV/mm to 2kV/mm, the shear modulus increased whereas the loss factor decreased. At all temperatures and electric field strengths of these investigations, both the shear modulus and loss factor increased in value as the excitation frequency was increased. The sets of measured temperature- and frequency-dependent data were converted, using the master curve technique, to master curves of shear modulus and loss factor which vary with frequency over several decades at a constant reference temperature and for varying levels of the electric field strength.

scholarly journals Effect of magnetic field strength on the linewidth and spin-lattice relaxation time of the thiocyanate carbon of cyanylated β-lactoglobulin B: optimization of the experimental parameters for observing thiocyanate carbons in proteins

1995 ◽  
Vol 306 (2) ◽  
pp. 531-535
Author(s):  
J P G Malthouse ◽  
P Phelan
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Magnetic Field Strength ◽  
Chemical Shift Anisotropy ◽  
Relaxation Times ◽  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Spin Lattice Relaxation Time ◽  
Spin Lattice ◽  
Field Strengths

The linewidths and spin-lattice relaxation times of the 13C-n.m.r. signal at 109.7 p.p.m. due to the thiocyanate carbon of intact [cyanato-13C]cyanylated-beta-lactoglobulin-B have been determined at magnetic field strengths of 1.88, 6.34 and 11.74 T as well as the spin-lattice relaxation times of its backbone alpha-carbon atoms. The linewidths were directly proportional to the square of the magnetic field strength and we conclude that, at magnetic field strengths of 6.34 T or above, more than 70% of the linewidth will be determined by chemical-shift anisotropy. We estimate that the spin-lattice relaxation time resulting from the chemical-shift anisotropy of the thiocyanate carbon is 1.52 +/- 0.1 s and we conclude that for magnetic field strengths of 6.34 T and above the observed spin-lattice relaxation time of the thiocyanate carbon will be essentially independent of magnetic field strength. Using the rigid-rotor model we obtain estimates of the rotational correlation time of [cyanato-13C]cyanylated-beta-lactoglobulin-B and of the chemical-shift anisotropy shielding tensor of its thiocyanate carbon. We have calculated the linewidths and spin-lattice relaxation times of thiocyanate carbons at magnetic field strengths of 1.88-14.1 T in proteins with M(r) values in the range 10,000-400,000. The effects of magnetic field strength on the resolution and signal-to-noise ratios of the signals due to thiocyanate carbons attached to proteins of M(r) greater than 10,000 are discussed.

Experimental Study of Finding Best Way of Radiation Seeds with HVEF

2011 ◽  
Vol 365 ◽  
pp. 440-444
Author(s):  
Jue Hang ◽  
Xin Chen ◽  
Jian Ping Xiong
Keyword(s):  
Experimental Study ◽  
Field Strength ◽  
High Voltage ◽  
Electrostatic Field ◽  
Radiation Transport ◽  
Clc Number ◽  
Document Code ◽  
Mathematical Derivation ◽  
Radiation Time ◽  
Germination Stage

Norder to find the best high-voltage electrostatic radiation seed program, to select two different kinds of cucumbers, vegetables, paddy rice seeds, each seed be divided into 5 experimental groups, and be treated by high voltage electrostatic field (HVEF) at different field strength and time, and testing and statistics of the seeds vigour at germination stage. The results indicated that the greater the radiation field to same seed, the shorter radiation time is required, and vice versa. For each species, E•t tends to a constant (the constant is different in different species). Be proved by mathematical derivation that the HVEF radiation transport essentially energy to the seed, and then will be able to find the best way for HVEF radiation seeds. CLC number: S129 Document code: A.

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