scholarly journals A Computational Model for the Analysis of Spreading of Viscoelastic Droplets over Flat Surfaces

Fluids ◽  
2018 ◽  
Vol 3 (4) ◽  
pp. 78 ◽  
Author(s):  
Aleck H. Alexopoulos ◽  
Costas Kiparissides
Keyword(s):  
Hyaluronic Acid ◽  
Acid Solution ◽  
Computational Model ◽  
Macroscopic Model ◽  
Curved Surfaces ◽  
Droplet Spreading ◽  
Flat Surfaces ◽  
Elastic Forces ◽  
Linear Viscoelastic ◽  
Linear Viscoelastic Fluid

The spreading of viscous and viscoelastic fluids on flat and curved surfaces is an important problem in many industrial and biomedical processes. In this work the spreading of a linear viscoelastic fluid with changing rheological properties over flat surfaces is investigated via a macroscopic model. The computational model is based on a macroscopic mathematical description of the gravitational, capillary, viscous, and elastic forces. The dynamics of droplet spreading are determined in sessile and pendant configurations for different droplet extrusion or formation times for a hyaluronic acid solution undergoing gelation. The computational model is employed to describe the spreading of hydrogel droplets for different extrusion times, droplet volumes, and surface/droplet configurations. The effect of extrusion time is shown to be significant in the rate and extent of spreading.

Development of a hydraulic driven bionic soft gecko toe

2021 ◽  
pp. 1-18
Author(s):  
Mingyue Lu ◽  
Guangming Chen ◽  
Qingsong He ◽  
Weijia Zong ◽  
Zhiwei Yu ◽  
...  
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Low Cost ◽  
Hydraulic Pressure ◽  
Curved Surfaces ◽  
Type B ◽  
Surface Conditions ◽  
Flat Surfaces ◽  
Soft Actuator ◽  
Output Force

Abstract Geckos can climb freely on various types of surfaces using their flexible and adhesive toes. Gecko-inspired robots are capable of climbing on different surface conditions and have shown many important applications. Nonetheless, due to poor flexibility of toes the movements of gecko-inspired robots are restricted to flat surfaces. To improve the flexibility, by utilizing design technique of soft actuator and incorporating the characteristics of a real gecko's toe, the design of new bionic soft toes is proposed. The abilities of this bionic toe are verified using modelling and two soft toes are manufactured. One is Type A toe having varied semi-circle cross-sections as the feature of real gecko toe and the other is Type B toe with a constant semi-circle cross-section. The bending behaviors of the bionic toes subjected to a range of hydraulic pressure are also experimentally studied. It demonstrated that both toes can perform similarly large bending angles for the adduction (attachment) and abduction (detachment) motions. In comparisons, Type B toe exhibits larger output force, which is ascribed to the fact that at proximal section of Type B corresponds to larger volume for bearing fluid. Both toes can not only provide sufficient adhesion, but can be quickly detached with low peeling forces. Finally, different curved surfaces are used to further justify the applicability of these bionic toes. In particular, the flexible toes developed also have the advantages of low cost, lightweight, and simple control, which is desirable for wall-climbing robots.

In Vivo Osteogenesis in Porous Hydroxyapatite Scaffold Processed in Hyaluronic Acid Solution

2007 ◽  
pp. 1185-1188
Author(s):  
Masataka Yoshikawa ◽  
T. Yabuuchi ◽  
N. Tsuji ◽  
Y. Shimomura ◽  
H. Hayashi ◽  
...  
Keyword(s):  
Hyaluronic Acid ◽  
Acid Solution ◽  
Porous Hydroxyapatite ◽  
Hydroxyapatite Scaffold

Unsteady Flow of a Non-Linear Viscoelastic Fluid in Pipes

2004 ◽  
Author(s):  
Mario F. Letelier ◽  
Nicola´s Madariaga ◽  
Dennis A. Siginer
Keyword(s):  
Velocity Field ◽  
Constitutive Equation ◽  
Pressure Gradient ◽  
Perturbation Method ◽  
Viscoelastic Fluid ◽  
Material Parameter ◽  
Ptt Model ◽  
Linear Viscoelastic ◽  
Dynamic Variables ◽  
Linear Viscoelastic Fluid

Flow of a viscoelastic fluid in round pipes is analyzed for the case where the pressure gradient is oscillatory with varying amplitude. The fluid is modelled according to Phan-Thien-Tanner’s constitutive equation. The analysis is carried out by using the perturbation method in which a material parameter is considered small. Velocity field and other kinematic and dynamic variables are evaluated for a range of relevant parameters. The results are compared with the base Newtonian and linear Maxwell flows. The effect of the PTT model in these type of flows is highlighted.

Thickening Effect of Hyaluronic Acid Solution in Foods with Different Intake Temperature

2019 ◽  
Vol 35 (02) ◽  
pp. 119-124
Author(s):  
Sun-Min Kim ◽  
Chae-Won An ◽  
Jin-Hee Chang ◽  
Dong-Keon Kweon ◽  
Joo-Yeon Hong ◽  
...  
Keyword(s):  
Hyaluronic Acid ◽  
Acid Solution

The role of protein content on the steady and oscillatory shear rheology of model synovial fluids

Soft Matter ◽  
2014 ◽  
Vol 10 (32) ◽  
pp. 5965-5973 ◽  
Author(s):  
Z. Zhang ◽  
S. Barman ◽  
G. F. Christopher
Keyword(s):  
Hyaluronic Acid ◽  
Synovial Fluid ◽  
Acid Solution ◽  
Protein Content ◽  
Shear Viscosity ◽  
Steady Shear ◽  
Interfacial Rheology ◽  
Steady Shear Viscosity ◽  
Synovial Fluids

Model synovial fluid steady shear viscosity to hyaluronic acid solution are identical when interfacial rheology effects are removed.

On the asymptotic behavior of a linear viscoelastic fluid

2012 ◽  
Vol 35 (7) ◽  
pp. 769-775 ◽  
Author(s):  
Mauro Fabrizio ◽  
Barbara Lazzari ◽  
Roberta Nibbi
Keyword(s):  
Asymptotic Behavior ◽  
Viscoelastic Fluid ◽  
Linear Viscoelastic ◽  
Linear Viscoelastic Fluid

Nanostructuring Curved Surfaces Using a Flexible Stamp

2009 ◽  
Author(s):  
Bahador Farshchian ◽  
JaeJong Lee ◽  
Sunggook Park
Keyword(s):  
Hot Embossing ◽  
Curved Surface ◽  
Curved Surfaces ◽  
Pmma Substrate ◽  
Pdms Stamp ◽  
Flat Surfaces ◽  
Force Microscopy ◽  
Atomic Force ◽  
Metallic Object ◽  
Planar Substrates

We report on a simple and effective process that allows direct imprinting of micro- and nanostructures on non-flat surfaces. A thin polydimethylsiloxane (PDMS) stamp having micro/nanogratings was placed between a metallic bar with a trapezoidal cross section or a metallic pellet and a flat polymethyl methacrylate (PMMA) substrate, followed by hot embossing at 200°C. During the hot embossing process, the metallic bar/pellet is pushed into the PMMA sheet forming a millimeter scale channel or a curved surface. Due to the presence of the PDMS stamp between the metallic object and the substrate, micro/nanostructures are produced into the channel or over the curved surface. With this method, we have successfully demonstrated micro- and nanostructures down to 300 nm wide gratings on non-flat substrates, as confirmed by scanning electron microscopy and atomic force microscopy. The process so developed will fill the gap in current micro- and nanofabrication technologies in that most of the technologies allow for patterning only on planar substrates.

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