Jet motion and fiber properties arising from a parallel electric field in melt-electrospinning

2020 ◽  
pp. 004051752096419
Author(s):  
Xueqin Li ◽  
Yuansheng Zheng ◽  
Xiaoqi Mu ◽  
Binjie Xin ◽  
Lantian Lin
Keyword(s):  
Electric Field ◽  
High Speed ◽  
Three Dimensional ◽  
Great Influence ◽  
Simulation Method ◽  
High Speed Photography ◽  
Outer Diameter ◽  
Electrospinning Technique ◽  
Fiber Properties ◽  
Melt Electrospinning

It is well known that the electric field has a great influence on the diameter and properties of fiber prepared via the melt-electrospinning technique. In this paper, two parallel metal discs were introduced to create a controllable electric field in the experiments. In addition, a three-dimensional electric field was calculated by the numerical simulation method and the jet motion was captured by taking advantage of high-speed photography technology. The influences of electric field distribution on the fiber jet, fiber diameter, fiber mat area and fiber crystallinity were studied in an in-depth and systematical manner. Both whipping amplitude and whipping frequency were also used to describe the characteristics of the jet. The above-mentioned results have proven that increasing the distance between the two parallel metal discs leads to the decrease of electric field intensity and the increase of electric field action time on the fiber, which together determine the diameter and crystallinity of the fiber. With the increase of the outer diameter of the upper disc, the distribution of the electric field becomes more uniform, making it capable of steadily controlling the behavior of the jet, and thus effectively reducing the diameter of the fiber and improving the crystallinity of the fiber.

Experiment and Numerical Simulation of Extrudate Swell in the Polymer Extrusion Process

2011 ◽  
Vol 314-316 ◽  
pp. 401-404 ◽  
Author(s):  
Min Zhang ◽  
Chuan Zhen Huang ◽  
Guo Wen Chen ◽  
Yu Xi Jia
Keyword(s):  
Numerical Simulation ◽  
High Speed ◽  
Three Dimensional ◽  
Simulation Method ◽  
Extrusion Process ◽  
High Speed Photography ◽  
The Finite Element Method ◽  
Polymer Extrusion ◽  
Extrudate Swell ◽  
Rate Profile

The extrudate swell of the polymer extrusion process was studied with the experiment and simulation method. The extrudate swell process was recorded by the high-speed photography apparatus. The swell rate at the different time was calculated. It is found that the extrudate swell rate increase at the first five seconds. The maximum swell rate is about 4.37%. The three-dimensional numerical simulation model of the experiment die path was founded. The extrusion process including the extrudate swell was simulated used the Finite Element Method. Such simulated results as the velocity vector, the shear rate profile and the end of the swell zone were analyzed. The extrudate swell end got by the simulation is similar with the experiment result.

Age-Related Differences in Throwing Techniques Used by the Catcher in Baseball

1994 ◽  
Vol 6 (3) ◽  
pp. 225-235 ◽  
Author(s):  
Shinji Sakurai ◽  
Bruce Elliott ◽  
J. Robert Grove
Keyword(s):  
High Speed ◽  
High Performance ◽  
Age Groups ◽  
Three Dimensional ◽  
Transformation Method ◽  
High Speed Photography ◽  
Two Phase ◽  
Ball Speed ◽  
Age Related ◽  
Release Speed

Three-dimensional (3-D) high speed photography was used to record the overarm throwing actions of five open-age, four 18-year-old, six 16-year- old, and six 14-year-old high-performance baseball catchers. The direct linear transformation method was used for 3-D space reconstruction from 2-D images of the catchers throwing from home plate to second base recorded using two phase-locked cameras operating at a nominal rate of 200 Hz. Selected physical capacity measures were also recorded and correlated with ball release speed. In general, anthropometric and strength measures significantly increased through the 14-year-old to open-age classifications, while a range of correlation coefficients from .50 to .84 was recorded between these physical capacities and ball speed at release. While many aspects of the kinematic data at release were similar, the key factors of release angle and release speed varied for the different age groups.

Experimental and Numerical Study of Hydrodynamic Cavitation of Orifice Plates with Multiple Triangular Holes

2012 ◽  
Vol 256-259 ◽  
pp. 2519-2522 ◽  
Author(s):  
Zhi Yong Dong ◽  
Qi Qi Chen ◽  
Yong Gang Yang ◽  
Bin Shi
Keyword(s):  
Velocity Profile ◽  
High Speed ◽  
Numerical Study ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Orifice Plate ◽  
Hydrodynamic Cavitation ◽  
High Speed Photography ◽  
Hydraulic Characteristics ◽  
Image Velocimetry

Hydraulic characteristics of orifice plates with multiple triangular holes in hydrodynamic cavitation reactor were experimentally investigated by use of three dimensional particle image velocimetry (PIV), high speed photography, electronic multi-pressure scanivalve and pressure data acquisition system, and numerically simulated by CFD software Flow 3D in this paper. Effects of number, arrangement and ratio of holes on hydraulic characteristics of the orifice plates were considered. Effects of arrangement and ratio of holes and flow velocity ahead of plate on cavitation number and velocity profile were compared. Distribution of turbulent kinetic energy and similarity of velocity profile were analyzed. And characteristics of cavitating flow downstream of the orifice plate were photographically observed by high speed camera. Also, a comparison with flow characteristics of orifice plate with hybrid holes (circle, square and triangle) was made.

scholarly journals A New Three-Dimensional Mobile Magnetic Melt Spinning Device

2021 ◽  
Author(s):  
Kai Zhang ◽  
Wu Zhao ◽  
Qingjie Liu ◽  
Miao Yu
Keyword(s):  
Electric Field ◽  
High Voltage ◽  
Melt Spinning ◽  
Three Dimensional ◽  
Fiber Surface ◽  
Electrospinning Process ◽  
Superior Performance ◽  
Fiber Morphology ◽  
High Voltage Power Supply ◽  
Melt Electrospinning

Abstract The size and morphology of nanofibers directly determine their application scope and performance, while regular patterned fibers further demonstrate their superior performance in the field of sensors and biomaterials. Melt electrospinning enables controlled deposition of fibers and is currently one of the most important means of preparing patterned fibers. However, due to the existence of high-voltage electric field, melt electrospinning has safety problems such as partial discharge and electric field breakdown, coupled with the charge rejection on the fiber surface, which seriously affects the positioning deposition of fibers and makes it difficult to obtain regular patterned fibers, greatly limiting the application areas and application effects of patterned fibers. Therefore, the improvement and innovation of the spinning process is particularly urgent. Based on material-field model and contradiction matrix of TRIZ theory, the problems of melt electrospinning device are systematically analyzed. The technical conflicts are solved by the inventive principles. A three-dimensional mobile magnetic melt spinning device model is constructed, a magnetic spinning test prototype is developed, and the prototype performance and influencing factors are studied by fiber morphology. The results show the following: (1) Replacing electrostatic fields with permanent magnetic fields can fundamentally avoid safety hazards such as electric field breakdown. (2) The magnetic field force on the molten polymer fluid can generate enough stretching force to overcome the surface tension and form fibers. (3) The fibers are deposited without a whipping instability phase similar to the electrospinning process, allowing easy preparation of regular patterned fibers. (4) The planar motion of the collector creates additional stretching effect on the fibers, which can further reduce the fiber diameter. (5) In magnetic spinning, no external high-voltage power supply is required, enabling the portability of the device. The results of this paper can provide a new method for preparing nanofibers with patterned morphology.

scholarly journals On compression and damage evolution in two thermoplastics

2017 ◽  
Vol 473 (2197) ◽  
pp. 20160495 ◽  
Author(s):  
N. K. Bourne ◽  
S. C. Garcea ◽  
D. S. Eastwood ◽  
S. Parry ◽  
C. Rau ◽  
...  
Keyword(s):  
High Speed ◽  
Deformation Behaviour ◽  
Three Dimensional ◽  
Spatial And Temporal Variation ◽  
High Speed Photography ◽  
Radial Deformation ◽  
X Ray Imaging ◽  
Series Of Experiments ◽  
The Impact ◽  
Continuous Range

The well-known Taylor cylinder impact test, which follows the impact of a flat-ended cylindrical rod onto a rigid stationary anvil, is conducted over a range of impact speeds for two polymers, polytetrafluoroethylene (PTFE) and polyetheretherketone (PEEK). In previous work, experiments and a model were developed to capture the deformation behaviour of the cylinder after impact. These works showed a region in which spatial and temporal variation of both longitudinal and radial deformation provided evidence of changes in phase within the material. In this further series of experiments, this region is imaged in a range of impacted targets at the Diamond synchrotron. Further techniques were fielded to resolve compressed regions within the recovered polymer cylinders that showed a fracture zone in the impact region. The combination of macroscopic high-speed photography and three-dimensional X-ray imaging has identified the development of failure with these polymers and shown that there is no abrupt transition in behaviours but rather a continuous range of responses to competing operating mechanisms. The behaviours noted in PEEK in these polymers show critical gaps in understanding of polymer high strain-rate response.

A Biomechanical Comparison of the Multisegment and Single Unit Topspin Forehand Drives in Tennis

1989 ◽  
Vol 5 (3) ◽  
pp. 350-364 ◽  
Author(s):  
Bruce Elliott ◽  
Tony Marsh ◽  
Peter Overheu
Keyword(s):  
Single Unit ◽  
High Speed ◽  
High Performance ◽  
Wrist Joint ◽  
Three Dimensional ◽  
Elbow Flexion ◽  
Unit Group ◽  
Transformation Method ◽  
Mean Value ◽  
High Speed Photography

Three-dimensional (3-D) high-speed photography was used to compare different forehand techniques of high performance players. Subjects, who hit a topspin forehand drive with the hitting limb moving almost as a single unit (Gs: single-unit group), were compared with players whose individual segments of the upper limb moved relative to each other (Gm: multisegment group) when playing the same stroke. The Direct Linear Transformation method was used for 3-D space reconstruction from 2-D images recorded from laterally placed phase-locked cameras operating at 200 fps. A third Photosonics camera operating at 100 fps filmed from overhead. Significant differences between the groups were recorded at the shoulder and elbow joints at the completion of the backswing. Maximal elbow joint angular velocities occurred 0.06 sec prior to impact, with the Gm group recording a significantly higher mean value for elbow extension than the Gs group. At impact, however, the Gm group recorded a significantly higher level of elbow flexion than the Gs group and achieved a higher mean angular velocity at the wrist joint than the Gs group. The Gm group recorded a higher racket tip linear velocity at impact and higher postimpact ball velocity when compared to the Gs group. The Gm technique of racket movement produced higher racket and ball velocities for this group of high performance players.

A Study of Hydraulic Characteristics of Multi-Square-Hole Orifice Plates

2012 ◽  
Vol 256-259 ◽  
pp. 2470-2473 ◽  
Author(s):  
Zhi Yong Dong ◽  
Yong Gang Yang ◽  
Qi Qi Chen ◽  
Bin Shi
Keyword(s):  
High Speed ◽  
Particle Image ◽  
Three Dimensional ◽  
Hydrodynamic Cavitation ◽  
High Speed Photography ◽  
Hydraulic Characteristics ◽  
System Pressure ◽  
Image Velocimetry ◽  
Working Section ◽  
Square Hole

This paper experimentally investigated hydraulic characteristics in working section of multi-square-hole orifice plates of hydrodynamic cavitation reactor by use of three-dimensional Particle Image Velocimetry (PIV) and High Speed Photography etc. Arrangements of holes in the orifice plates can be divided into diagonal, cross and checkerboard categories. The three-dimensional velocity distribution, pressure and cavitation characteristics for each arrangement of multi-hole orifice plates were measured by PIV system, pressure data acquisition system and high speed camera, and a comparison of hydraulic characteristics of the three categories of arrangements of the multi-hole orifice plates were made.

scholarly journals Design and Analysis of Broadband LiNbO3 Optical Waveguide Electric Field Sensor with Tapered Antenna

Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3672
Author(s):  
Haiying Lu ◽  
Yingna Li ◽  
Jiahong Zhang
Keyword(s):  
Electric Field ◽  
Resonance Frequency ◽  
Optical Waveguide ◽  
Three Dimensional ◽  
Great Influence ◽  
Simulation Software ◽  
Substrate Thickness ◽  
Electric Field Sensor ◽  
Field Sensor ◽  
Simulation Results

The three-dimensional (3D) simulation model of a lithium niobate (LiNbO3, LN) optical waveguide (OWG) electric field sensor has been established by using the full-wave electromagnetic simulation software. The influences of the LN substrate and the packaging material on the resonance frequency of the integrated OWG electric field sensor have been simulated and analyzed. The simulation results show that the thickness of the LN substrate has a great influence on the resonant frequency of the sensor (≈33.4%). A sensor with a substrate thickness of 1 mm has been designed, fabricated, and experimentally investigated. Experimental results indicate that the measured resonance frequency is 7.5 GHz, which nearly coincides with the simulation results. Moreover, the sensor can be used for the measurement of the nanosecond electromagnetic impulse (NEMP) in the time domain from 1.29 kV/m to 100.97 kV/m.

scholarly journals New finite-difference formulas for dielectric interfaces

2010 ◽  
Vol 23 (1) ◽  
pp. 17-35
Author(s):  
Dusan Djurdjevic
Keyword(s):  
Finite Difference ◽  
Finite Difference Method ◽  
Electric Field ◽  
Difference Method ◽  
Three Dimensional ◽  
Power Series Expansion ◽  
Transverse Field ◽  
Cost Effective ◽  
Simulation Method ◽  
Dielectric Interfaces

The finite difference method is often-used numerical simulation method in electromagnetics. In this paper a new methodology is presented that allows the derivation of finite difference formulas near dielectric interfaces with high accuracy. Derived finite difference formulas have been used in the electric field computations in electrostatics (the two-dimensional Laplace's equation is employed) and in full-vectorial waveguide simulations in photonics (the three-dimensional Helmholtz's equation and the beam propagation simulation technique in frequency domain are employed). The finite difference formulas derivation is made under a power series expansion of the transverse field components in the case for uniform rectangular discretization mesh. The resulting finite difference formulas provide highly accurate solutions, both for electrostatic and waveguide propagation problems even on coarse grids and thus enable a very cost-effective and rapid numerical field simulations. Reported methodology and derived formulas have not been used in finite difference method formulations in literature. Some results for the electric field computation and dielectric waveguide eigenmode and propagation analysis are presented. .

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