Spontaneous Fabrication of Three-Dimensional Multiscale Fractal Structures Using Hele-Shaw Cell

2016 ◽  
Vol 139 (3) ◽  
Author(s):  
Tanveer ul Islam ◽  
Prasanna S. Gandhi
Keyword(s):  
Thin Layer ◽  
Respiratory System ◽  
Blood Circulation ◽  
Multiple Scales ◽  
Three Dimensional ◽  
Fabrication Process ◽  
Fractal Structures ◽  
Ceramic Suspension ◽  
Polystyrene Solution ◽  
Hele Shaw Cell

Several biosystems such as leaf veins, respiratory system, blood circulation, and some plant xylem involving multiscale fractal topologies are being mimic for their inherent natural optimization. Three-dimensional fractal structures spanning multiple scales are difficult to fabricate. In this paper, we demonstrate a new method to fabricate structures spanning meso- and microscale in a relatively easy and inexpensive manner. A well-known Saffman–Taylor instability is exploited for the same in a lifted Hele-Shaw cell. In this cell, a thin layer of liquid is squeezed between two plates being lifted angularly leaving behind the fractal rearrangement of fluid which is proposed to be solidified later. We demonstrate and characterize fractal structures fabricated using two different fluids and corresponding methods of solidification. The first one is ceramic suspension in a photopolymer and another is polystyrene solution with photopolymerization and solvent vaporization as methods of solidification, respectively. The fabrication process is completed in period of a few seconds.

Spontaneous Fabrication of Three Dimensional Multi-Scale Fractal Structures Using Hele Shaw Cell

2016 ◽  
Author(s):  
Tanveer ul Islam ◽  
Prasanna S. Gandhi
Keyword(s):  
Blood Circulation ◽  
Multiple Scales ◽  
Three Dimensional ◽  
Fractal Structures ◽  
Ceramic Suspension ◽  
Micro Scale ◽  
Multi Scale ◽  
Photo Polymerization ◽  
Polystyrene Solution ◽  
Hele Shaw Cell

Several bio-systems such as leaf veins, respiratory system, blood circulation, some plant xylem etc., involving multi-scale fractal topologies are being mimic for their inherent natural optimization. 3D fractal structures spanning multiple scales are difficult to fabricate. In this paper we demonstrate a new method to fabricate structures spanning meso and micro-scale in a relatively easy and inexpensive manner. A well known Saffman-Taylor instability is exploited for the same in a lifted Hele-Shaw cell. In this cell a thin layer of liquid is squeezed between two plates being lifted angularly leaving behind the fractal rearrangement of fluid which is proposed to be solidified later. We demonstrate and characterize fractal structures fabricated using two different fluids and corresponding methods of solidification. The first one is ceramic suspension in a photo-polymer and another is polystyrene solution with photo-polymerization and solvent vaporization as methods of solidification respectively. The fabrication process is completed in period of a few seconds.

Microstructures of Low Angle Boundaries of the Second Generation Single Crystal Superalloy DD6

2011 ◽  
Vol 284-286 ◽  
pp. 1584-1587
Author(s):  
Zhen Xue Shi ◽  
Jia Rong Li ◽  
Shi Zhong Liu ◽  
Jin Qian Zhao
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Scanning Electron Microscope ◽  
Thin Layer ◽  
Single Crystal ◽  
Second Generation ◽  
Three Dimensional ◽  
Single Crystal Superalloy ◽  
Transition Electron ◽  
Scanning Electron

The specimens of low angle boundaries were machined from the second generation single crystal superalloy DD6 blades. The microstructures of low angle boundaries (LAB) were investigated from three scales of dendrite, γ′ phase and atom with optical microscopy (OM), scanning electron microscope (SEM), transition electron microscope (TEM) and high resolution transmission electrion microscopy (HREM). The results showed that on the dendrite scale LAB is interdendrite district formed by three dimensional curved face between the adjacent dendrites. On the γ′ phase scale LAB is composed by a thin layer γ phase and its bilateral imperfect cube γ′ phase. On the atom scale LAB is made up of dislocations within several atom thickness.

Density-driven unstable flows of miscible fluids in a Hele-Shaw cell

2002 ◽  
Vol 451 ◽  
pp. 239-260 ◽  
Author(s):  
J. FERNANDEZ ◽  
P. KUROWSKI ◽  
P. PETITJEANS ◽  
E. MEIBURG
Keyword(s):  
Stokes Equations ◽  
Three Dimensional ◽  
Brinkman Equation ◽  
Length Scale ◽  
Dominant Wavelength ◽  
Miscible Fluids ◽  
Nonlinear Simulations ◽  
Instability Growth ◽  
Gap Width ◽  
Hele Shaw Cell

Density-driven instabilities between miscible fluids in a vertical Hele-Shaw cell are investigated by means of experimental measurements, as well as two- and three-dimensional numerical simulations. The experiments focus on the early stages of the instability growth, and they provide detailed information regarding the growth rates and most amplified wavenumbers as a function of the governing Rayleigh number Ra. They identify two clearly distinct parameter regimes: a low-Ra, ‘Hele-Shaw’ regime in which the dominant wavelength scales as Ra−1, and a high-Ra ‘gap’ regime in which the length scale of the instability is 5±1 times the gap width. The experiments are compared to a recent linear stability analysis based on the Brinkman equation. The analytical dispersion relationship for a step-like density profile reproduces the experimentally observed trend across the entire Ra range. Nonlinear simulations based on the two- and three-dimensional Stokes equations indicate that the high-Ra regime is characterized by an instability across the gap, wheras in the low-Ra regime a spanwise Hele-Shaw mode dominates.

Fabrication of thin-layer matrigel-based constructs for three-dimensional cell culture

2018 ◽  
Vol 35 (1) ◽  
pp. e2733 ◽  
Author(s):  
Kristin Robin Ko ◽  
Meng-Chiao Tsai ◽  
John P. Frampton
Keyword(s):  
Cell Culture ◽  
Thin Layer ◽  
Three Dimensional ◽  
Dimensional Cell

Thin-layer approximation for three-dimensional supersonic corner flows

AIAA Journal ◽  
1980 ◽  
Vol 18 (12) ◽  
pp. 1544-1546 ◽  
Author(s):  
C. M. Hung ◽  
Seth S. Kurasaki
Keyword(s):  
Thin Layer ◽  
Three Dimensional ◽  
Thin Layer Approximation ◽  
Corner Flows

Numerical and theoretical analyses of the dynamics of droplets driven by electrowetting on dielectric in a Hele-Shaw cell

2018 ◽  
Vol 839 ◽  
pp. 468-488 ◽  
Author(s):  
Yasufumi Yamamoto ◽  
Takahiro Ito ◽  
Tatsuro Wakimoto ◽  
Kenji Katoh
Keyword(s):  
Theoretical Model ◽  
Contact Line ◽  
Three Dimensional ◽  
Simulation Method ◽  
Movement Speed ◽  
Electrowetting On Dielectric ◽  
Moving Contact Line ◽  
Moving Contact ◽  
Droplet Movement ◽  
Hele Shaw Cell

Droplet movement by electrowetting on dielectric (EWOD) in a Hele-Shaw cell is analysed theoretically and numerically. We propose a simple theoretical model for the motion, which describes well the voltage dependency of droplet speed below the saturation voltage as measured experimentally. The simulation method for numerical analyses is constructed by using the Young–Lippmann equation to represent EWOD and the generalised Navier boundary condition to represent the moving contact line in the context of the front-tracking method. With an adjusted slip parameter, the present full three-dimensional numerical simulation reproduces well the shape evolution and movement speed of droplets as observed experimentally. We verify the proposed theoretical model in numerical experiments with various shapes and voltages. Furthermore, we analyse theoretically the behaviour of the contact line at the onset of droplet motion as observed in the simulation and experiment, and we are able to estimate very well the time scale on which the contact angle changes.

A Novel Scheme for Wide Bandwidth Chip-to-Chip Communications

2007 ◽  
Vol 4 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Qing Liu ◽  
Patrick Fay ◽  
Gary H. Bernstein
Keyword(s):  
Integrated Circuits ◽  
Coplanar Waveguide ◽  
Impedance Matching ◽  
Three Dimensional ◽  
Fabrication Process ◽  
Silicon Substrates ◽  
Electromagnetic Simulations ◽  
Communication Paradigm ◽  
On Chip ◽  
Test Chips

Quilt Packaging (QP), a novel chip-to-chip communication paradigm for system-in-package integration, is presented. By forming protruding metal nodules along the edges of the chips and interconnecting integrated circuits (ICs) through them, QP offers an approach to ameliorate the I/O speed bottleneck. A fabrication process that includes deep reactive ion etching, electroplating, and chemical-mechanical polishing is demonstrated. As a low-temperature process, it can be easily integrated into a standard IC fabrication process. Three-dimensional electromagnetic simulations of coplanar waveguide QP structures have been performed, and geometries intended to improve impedance matching at the interface between the on-chip interconnects and the chip-to-chip nodule structures were evaluated. Test chips with 100 μm wide nodules were fabricated on silicon substrates, and s-parameters of chip-to-chip interconnects were measured. The insertion loss of the chip-to-chip interconnects was as low as 0.2 dB at 40 GHz. Simulations of 20 μm wide QP structures suggest that the bandwidth of the inter-chip nodules is expected to be above 200 GHz.

New techniques for imaging, digitization and analysis of three-dimensional neural morphology on multiple scales

Neuroscience ◽  
2005 ◽  
Vol 136 (3) ◽  
pp. 661-680 ◽  
Author(s):  
S.L. Wearne ◽  
A. Rodriguez ◽  
D.B. Ehlenberger ◽  
A.B. Rocher ◽  
S.C. Henderson ◽  
...  
Keyword(s):  
Multiple Scales ◽  
Three Dimensional ◽  
New Techniques

scholarly journals Challenges in a Hybrid Fabrication Process to Generate Metallic Polarization Elements with Sub-Wavelength Dimensions

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5279
Author(s):  
Stefan Belle ◽  
Babette Goetzendorfer ◽  
Ralf Hellmann
Keyword(s):  
Final Height ◽  
Three Dimensional ◽  
Fabrication Process ◽  
Degree Of Polarization ◽  
Direct Laser Writing ◽  
Free Standing ◽  
Laser Writing ◽  
Additive Fabrication ◽  
Direct Laser ◽  
Sub Wavelength

We report on the challenges in a hybrid sub-micrometer fabrication process while using three dimensional femtosecond direct laser writing and electroplating. With this hybrid subtractive and additive fabrication process, it is possible to generate metallic polarization elements with sub-wavelength dimensions of less than 400 nm in the cladding area. We show approaches for improving the adhesion of freestanding photoresist pillars as well as of the metallic cladding area, and we also demonstrate the avoidance of an inhibition layer and sticking of the freestanding pillars. Three-dimensional direct laser writing in a positive tone photoresist is used as a subtractive process to fabricate free-standing non-metallic photoresist pillars with an area of about 850 nm × 1400 nm, a height of 3000 nm, and a distance between the pillars of less than 400 nm. In a subsequent additive fabrication process, these channels are filled with gold by electrochemical deposition up to a final height of 2200 nm. Finally, the polarization elements are characterized by measuring the degree of polarization in order to show their behavior as quarter- and half-wave plates.

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