scholarly journals Electrohydrodynamic Direct-Writing Micropatterns with Assisted Airflow

Micromachines ◽  
2018 ◽  
Vol 9 (9) ◽  
pp. 456 ◽  
Author(s):  
Jiaxin Jiang ◽  
Xiang Wang ◽  
Wenwang Li ◽  
Juan Liu ◽  
Yifang Liu ◽  
...  
Keyword(s):  
High Resolution ◽  
Flow Field ◽  
Structure Design ◽  
Direct Writing ◽  
Position Accuracy ◽  
Positioning Errors ◽  
Jet Stability ◽  
Series Of Experiments ◽  
Printed Patterns ◽  
Deposition Position

Electrohydrodynamic direct-writing (EDW) is a developing technology for high-resolution printing. How to decrease the line width and improve the deposition accuracy of direct-written patterns has been the key to the promotion for the further application of EDW. In this paper, an airflow-assisted spinneret for electrohydrodynamic direct-writing was designed. An assisted laminar airflow was introduced to the EDW process, which provided an additional stretching and constraining force on the jet to reduce the surrounding interferences and enhance jet stability. The flow field and the electric field around the spinneret were simulated to direct the structure design of the airflow-assisted spinneret. Then, a series of experiments were conducted, and the results verified the spinneret design and demonstrated a stable ejection of jet in the EDW process. With assisted airflow, the uniformity of printed patterns and the deposition position accuracy of a charged jet can be improved. Complex patterns with positioning errors of less than 5% have been printed and characterized, which provide an effective way to promote the integration of micro/nanosystems.

High-resolution additive direct writing of metal micro/nanostructures by electrohydrodynamic jet printing

2021 ◽  
Vol 543 ◽  
pp. 148800
Author(s):  
Wuhao Zou ◽  
Haibo Yu ◽  
Peilin Zhou ◽  
Ya Zhong ◽  
Yuechao Wang ◽  
...  
Keyword(s):  
High Resolution ◽  
Direct Writing ◽  
Electrohydrodynamic Jet Printing ◽  
Jet Printing

scholarly journals Jet stability and wall impingement flow field in a thermal striping experiment

2017 ◽  
Vol 115 ◽  
pp. 1125-1136 ◽  
Author(s):  
S. Lomperski ◽  
A. Obabko ◽  
E. Merzari ◽  
P. Fischer ◽  
W.D. Pointer
Keyword(s):  
Flow Field ◽  
Jet Stability ◽  
Wall Impingement ◽  
Thermal Striping

Two-Scale Topology Optimization With Parameterized Cellular Structures

2021 ◽  
Author(s):  
Sina Rastegarzadeh ◽  
Jun Wang ◽  
Jida Huang
Keyword(s):  
Topology Optimization ◽  
High Resolution ◽  
Structural Optimization ◽  
Optimization Problem ◽  
Material Design ◽  
Homogenization Method ◽  
Elasticity Tensor ◽  
Structure Design ◽  
Cellular Structures ◽  
Mapping Technique

Abstract Advances in additive manufacturing enable the fabrication of complex structures with intricate geometric details. It also escalates the potential for high-resolution structure design. However, the increasingly finer design brings computational challenges for structural optimization approaches such as topology optimization (TO) since the number of variables to optimize increases with the resolutions. To address this issue, two-scale TO paves an avenue for high-resolution structural design. The design domain is first discretized to a coarse scale, and the material property distribution is optimized, then using micro-structures to fill each property field. In this paper, instead of finding optimal properties of two scales separately, we reformulate the two-scale TO problem and optimize the design variables concurrently in both scales. By introducing parameterized periodic cellular structures, the minimal surface level-parameter is defined as the material design parameter and is implemented directly in the optimization problem. A numerical homogenization method is employed to calculate the elasticity tensor of the cellular materials. The stiffness matrices of the cellular structures derived as a function of the level parameters, using the homogenization results. An additional constraint on the level parameter is introduced in the structural optimization framework to enhance adjacent cellulars interfaces’ compatibility. Based on the parameterized micro-structure, the optimization problem is solved concurrently with an iterative solver. The reliability of the proposed approach has been validated with different engineering design cases. Numerical results show a noticeable increase in structure stiffness using the level parameter directly in the optimization problem than the state-of-art mapping technique.

scholarly journals Jet Mode Recognition of Electrohydrodynamic Direct-Writing Based on Micro/Nano Current

Micromachines ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 128
Author(s):  
Guoyi Kang ◽  
Gaofeng Zheng ◽  
Yanping Chen ◽  
Jiaxin Jiang ◽  
Huatan Chen ◽  
...  
Keyword(s):  
Taylor Cone ◽  
Direct Writing ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Peak Current ◽  
Loop Control ◽  
Jet Stability ◽  
Mode Recognition ◽  
Patterned Structures ◽  
Current Characteristics

The online recognition of jet mode is important for the accurate control and further application of electrohydrodynamic direct-writing (EDW) technology. An EDW system with a current detection module is built for jet mode recognition. The current of the EDW jet is measured to recognize the jet mode when printing patterned structures. Then, a data processing program with a digital Kaiser low-pass filter is developed in MATLAB, via which the noise of the current signal is reduced. The features of EDW current, including the current fluctuation and the peak current intervals, are studied to recognize different jet modes. The current characteristics of three jet modes are investigated: droplet ejection mode, Taylor cone ejection mode, and retractive ejection mode. The Taylor cone ejection mode has the smallest coefficient of variation of peak current. This work provides a good way of designing the optimized control algorithm and of realizing the closed-loop control system, which contributes to enhancing the jet stability and accelerating the application of EDW technology.

A time-lapse seismic repeatability test using the P-Cable high-resolution 3D marine acquisition system

2020 ◽  
Vol 39 (7) ◽  
pp. 480-487
Author(s):  
Patrick Smith ◽  
Brandon Mattox
Keyword(s):  
High Resolution ◽  
Seismic Data ◽  
Low Cost ◽  
Low Frequency ◽  
Time Lapse ◽  
Seismic Signal ◽  
Residual Energy ◽  
Acquisition System ◽  
Positioning Errors ◽  
Seismic Surveying

The P-Cable high-resolution 3D marine acquisition system tows many short, closely separated streamers behind a small source. It can provide 3D seismic data of very high temporal and spatial resolution. Since the system is containerized and has small dimensions, it can be deployed at short notice and relatively low cost, making it attractive for time-lapse seismic reservoir monitoring. During acquisition of a 3D high-resolution survey in the Gulf of Mexico in 2014, a pair of sail lines were repeated to form a time-lapse seismic test. We processed these in 2019 to evaluate their geometric and seismic repeatability. Geometric repetition accuracy was excellent, with source repositioning errors below 10 m and bin-based receiver positioning errors below 6.25 m. Seismic data comparisons showed normalized root-mean-square difference values below 10% between 40 and 150 Hz. Refinements to the acquisition system since 2014 are expected to further improve repeatability of the low-frequency components. Residual energy on 4D difference seismic data was low, and timing stability was good. We conclude that the acquisition system is well suited to time-lapse seismic surveying in areas where the reservoir and time-lapse seismic signal can be adequately imaged by small-source, short-offset, low-fold data.

Study on Flow Field in Different Styles of Blades for Eddy Current Retarder’s Rotor Based on CFD

2011 ◽  
Vol 480-481 ◽  
pp. 1134-1139
Author(s):  
Jian Ming Shen ◽  
Cheng Ye Liu
Keyword(s):  
Flow Field ◽  
Eddy Current ◽  
Energy Equation ◽  
Static Pressure ◽  
Mechanical Energy ◽  
Structure Design ◽  
Heat Energy ◽  
Braking Performance ◽  
Eddy Current Retarder ◽  
Heat Elimination

Eddy current retarder was a retarder braking set used in an automobile, and it can transform kinetic energy or mechanical energy of the automobile into heat energy, and heat energy was emitted around environment by the blades founded in the rotor of eddy current retarder, so flow field within the blade had direct effect on heat elimination and braking performance. In this paper two styles of 2D computational model for the rotor had been established. The flow field between and out of blades were analyzed by using RNG Κ-ε model and energy equation. The velocity distribution, pressure distribution between blades, static pressure on work face and rear face of the blade along radial direction all were accepted. The pressure, velocity and air flux for two styles of the blades had been compared. Numerical analysis of flow field was in favor of improved structure design for the blade.

Flow Field Analysis of PVC Polymerizer

2014 ◽  
Vol 884-885 ◽  
pp. 68-72
Author(s):  
Hui Di Hao ◽  
Tian Qi Cheng ◽  
Yong Fang Zhang ◽  
Na Zhu ◽  
Jian Yong Lei ◽  
...  
Keyword(s):  
Flow Field ◽  
Design Method ◽  
Suspension Polymerization ◽  
Calculation Model ◽  
Structure Design ◽  
Raw Material ◽  
Field Analysis ◽  
Stirred Tank ◽  
Chemical Production ◽  
Complex Flow

Stirred tank reactor is one of the three typical chemical machinery equipments and widely used in petroleum, chemical, pharmaceutical and other industrial fields .It is the basis of understanding the flow of fluid in stirred tank for optimizing design of reactor. This paper aims at the process of suspension polymerization of polyvinyl chloride (PVC) which is an important raw material of chemical production, and uses conventional design method to design the PVC stirred tank of 50m3 from the structure design. According to the fluid dynamics theory, standard K-E turbulent calculation model is established under the function of impeller, the corresponding boundary conditions are listed, and the grid is carried out successfully. And finally the FLOTRAN CFD software is used to simulate the complex flow field and flow pattern according to the multiple reference frame method.

Surface Microfabrication of Conventional Glass Using Femtosecond Laser for Microfluidic Applications

2017 ◽  
Vol 11 (6) ◽  
pp. 878-882 ◽  
Author(s):  
Takuma Niioka ◽  
◽  
Yasutaka Hanada
Keyword(s):  
High Resolution ◽  
Microfluidic Chip ◽  
High Speed ◽  
Single Cell Analysis ◽  
Glass Slide ◽  
Cell Analysis ◽  
Microfluidic Chips ◽  
Direct Writing ◽  
Laser Direct Writing ◽  
Fs Laser

Recently, a lot of attention has been paid to a single-cell analysis using microfluidic chips, since each cell is known to have several different characteristics. The microfluidic chip manipulates cells and performs high-speed and high-resolution analysis. In the meanwhile, femtosecond (fs) laser has become a versatile tool for the fabrication of microfluidic chips because the laser can modify internal volume solely at the focal area, resulting in three-dimensional (3D) microfabrication of glass materials. However, little research on surface microfabrication of materials using an fs laser has been conducted. Therefore, in this study, we demonstrate the surface microfabrication of a conventional glass slide using fs laser direct-writing for microfluidic applications. The fs laser modification, with successive wet etching using a diluted hydrofluoric (HF) acid solution, followed by annealing, results in rapid prototyping of microfluidics on a conventional glass slide for fluorescent microscopic cell analysis. Fundamental characteristics of the laser-irradiated regions in each experimental procedure were investigated. In addition, we developed a novel technique combining the fs laser direct-writing and the HF etching for high-speed and high-resolution microfabrication of the glass. After establishing the fs laser surface microfabrication technique, a 3D microfluidic chip was made by bonding the fabricated glass microfluidic chip with a polydimethylsiloxane (PDMS) polymer substrate for clear fluorescent microscopic observation in the microfluidics.

Electrohydrodynamic printing of silver nanowires for flexible and stretchable electronics

Nanoscale ◽  
2018 ◽  
Vol 10 (15) ◽  
pp. 6806-6811 ◽  
Author(s):  
Zheng Cui ◽  
Yiwei Han ◽  
Qijin Huang ◽  
Jingyan Dong ◽  
Yong Zhu
Keyword(s):  
Electrical Conductivity ◽  
High Resolution ◽  
Line Width ◽  
Large Scale ◽  
Silver Nanowires ◽  
Stretchable Electronics ◽  
Electrohydrodynamic Printing ◽  
Printed Patterns ◽  
Flexible And Stretchable Electronics

High-resolution, large-scale printing of highly conductive AgNWs for flexible and stretchable electronics using EHD printing is presented. The printed patterns show the smallest line width of 45 μm and electrical conductivity as high as ∼5.6 × 106S m−1. AgNW-based wearable heaters and ECG electrodes are fabricated.

Sign in / Sign up

Export Citation Format

Share Document