Controlled locomotion of a droplet propelled by an encapsulated squirmer

Abstract We work out the propulsion of a viscous drop which is driven by two mechanisms: the active velocity of an encapsulated squirmer and an externally applied force acting on the squirmer. Of particular interest is the existence of a stable comoving state of drop and squirmer, allowing for controlled manipulation of the viscous drop by external forcing. The velocities of droplet and squirmer, as well as the conditions for a stable comoving state are worked out analytically for the axisymmetric configuration with a general displacement of the squirmer from the center of the droplet Graphic abstract

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Study of the Origin of Three Dimensional Structures in Shear Flows through External Forcing

10.21236/ada221923 ◽

1990 ◽

Author(s):

M. Gharib ◽

K. Williams

Keyword(s):

Shear Flows ◽

Three Dimensional ◽

External Forcing

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On Time Scales of Intrinsic Oscillations in the Climate System

Entropy ◽

10.3390/e23040459 ◽

2021 ◽

Vol 23 (4) ◽

pp. 459

Author(s):

Anastasios A. Tsonis ◽

Geli Wang ◽

Wenxu Lu ◽

Sergey Kravtsov ◽

Christopher Essex ◽

...

Keyword(s):

Low Frequency ◽

Milankovitch Cycles ◽

Data Sets ◽

External Forcing ◽

Natural Oscillations ◽

Climatic Oscillations ◽

Slow Feature Analysis ◽

Limited Length ◽

Past Data ◽

Cumulative Evidence

Proxy temperature data records featuring local time series, regional averages from areas all around the globe, as well as global averages, are analyzed using the Slow Feature Analysis (SFA) method. As explained in the paper, SFA is much more effective than the traditional Fourier analysis in identifying slow-varying (low-frequency) signals in data sets of a limited length. We find the existence of a striking gap from ~1000 to about ~20,000 years, which separates intrinsic climatic oscillations with periods ranging from ~ 60 years to ~1000 years, from the longer time-scale periodicities (20,000 yr +) involving external forcing associated with Milankovitch cycles. The absence of natural oscillations with periods within the gap is consistent with cumulative evidence based on past data analyses, as well as with earlier theoretical and modeling studies.

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Electrodilatometric analysis under applied force: a powerful tool for electrode investigation

Electrochimica Acta ◽

10.1016/j.electacta.2021.137938 ◽

2021 ◽

pp. 137938

Author(s):

Giampaolo Lacarbonara ◽

Morteza Rahmanipour ◽

Juri Belcari ◽

Lorenzo Lodi ◽

Andrea Zucchelli ◽

...

Keyword(s):

Applied Force

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A Soft Resistive Sensor with a Semicircular Cross-Sectional Channel for Soft Cardiac Catheter Ablation

Sensors ◽

10.3390/s21124130 ◽

2021 ◽

Vol 21 (12) ◽

pp. 4130

Author(s):

Eric Rasmussen ◽

Daniel Guo ◽

Vybhav Murthy ◽

Rachit Mishra ◽

Cameron Riviere ◽

...

Keyword(s):

Catheter Ablation ◽

Liquid Metal ◽

Force Feedback ◽

Applied Force ◽

Medical Community ◽

Soft Robotics ◽

Soft Sensors ◽

Cross Sectional ◽

Cardiac Catheter ◽

Specific Loading

The field of soft robotics has attracted the interest of the medical community due to the ability of soft elastic materials to traverse the abnormal environment of the human body. However, sensing in soft robotics has been challenging due to the sensitivity of soft sensors to various loading conditions and the nonlinear signal responses that can arise under extreme loads. Ideally, soft sensors should provide a linear response under a specific loading condition and provide a different response for other loading directions. With these specifications in mind, our team created a soft elastomeric sensor designed to provide force feedback during cardiac catheter ablation surgery. Analytical and computational methods were explored to define a relationship between resistance and applied force for a semicircular, liquid metal filled channel in the soft elastomeric sensor. Pouillet’s Law is utilized to calculate the resistance based on the change in cross-sectional area resulting from various applied pressures. FEA simulations were created to simulate the deformation of the sensor under various loads. To confirm the validity of these simulations, the elastomer was modeled as a neo-Hookean material and the liquid metal was modeled as an incompressible fluid with negligible shear modulus under uniaxial compression. Results show a linearly proportional relationship between the resistance of the sensor and the application of a uniaxial force. Altering the direction of applied force results in a quadratic relationship between total resistance and the magnitude of force.

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Size Scale Effect on Generated Electric Potential of Nano Composite Electrical Generators

Volume 8: Mechanics of Solids, Structures and Fluids ◽

10.1115/imece2012-85590 ◽

2012 ◽

Author(s):

Kasra Momeni

Keyword(s):

Elastic Modulus ◽

Scale Effect ◽

Electric Potential ◽

Zno Nanowires ◽

Surface Model ◽

Multiscale Approach ◽

Nano Composite ◽

Size Scale ◽

Cylindrical Coordinate ◽

Axisymmetric Configuration

A multiscale approach is pursued for modeling the size-scale effect on generated electric potential by nanocomposite electrical generators of ZnO nanowires. A core-surface model is used for capturing the effect of size-scale on elastic modulus of ZnO NWs. In this model, a surface with different elastic modulus as of the core of NW was considered. Using linear elasticity and axisymmetric configuration of this problem, closed form governing equations are derived in cylindrical coordinate system. Parametric studied are performed for sample cases to demonstrate application of the developed model. It is shown that ZnO nanowires with larger aspect ratio and smaller diameters have higher performance and can produce higher electric potential.

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A NEW FORMULA FOR THE MASS OF A STATIONARY AXISYMMETRIC CONFIGURATION

Modern Physics Letters A ◽

10.1142/s0217732395000909 ◽

1995 ◽

Vol 10 (10) ◽

pp. 841-844 ◽

Cited By ~ 2

Author(s):

R. M. AVAKIAN ◽

G. OGANESSYAN

Keyword(s):

Pressure Distribution ◽

Spherical Coordinates ◽

New Formula ◽

Axisymmetric Configuration

It has been shown by one of the authors1 that in isotropic spherical coordinates there is a relation between the mass of a static spherical gravitating body and the pressure distribution inside it. In this paper the result is generalized for the case of stationary axisymmetric configurations.

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A Method to Improve the Modal Convergence for Structures With External Forcing

Journal of Applied Mechanics ◽

10.1115/1.3173137 ◽

1987 ◽

Vol 54 (4) ◽

pp. 904-909 ◽

Cited By ~ 18

Author(s):

Keqin Gu ◽

Benson H. Tongue

Keyword(s):

Spatial Distribution ◽

Free Vibration ◽

Convergence Rate ◽

Traditional Approach ◽

Vibration Modes ◽

External Forcing ◽

Slow Convergence ◽

Assumed Mode Method ◽

Mode Method ◽

Assumed Mode

The traditional approach of using free vibration modes in the assumed mode method often leads to an extremely slow convergence rate, especially when discete interactive forces are involved. By introducing a number of forced modes, significant improvements can be achieved. These forced modes are intrinsic to the structure and the spatial distribution of forces. The motion of the structure can be described exactly by these forced modes and a few free vibration modes provided that certain conditions are satisfied. The forced modes can be viewed as an extension of static modes. The development of a forced mode formulation is outlined and a numerical example is presented.

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Unfolding a Curved Elastic Sheet

Journal of Mechanical Engineering Science ◽

10.1243/jmes_jour_1981_023_042_02 ◽

1981 ◽

Vol 23 (5) ◽

pp. 217-219 ◽

Cited By ~ 2

Author(s):

C.-Y. Wang

Keyword(s):

Flat Plate ◽

Numerical Integration ◽

Flexural Rigidity ◽

Elliptic Functions ◽

Applied Force ◽

Relative Importance ◽

Dimensional Parameter ◽

Elastic Sheet ◽

Leaf Springs ◽

Force Displacement

A curved elastic sheet is flattened on a rigid flat plate by vertical end forces. The problem is governed by a non-dimensional parameter, B, which signifies the relative importance of flexural rigidity to the applied force and the natural radius. The elastica equations are solved by elliptic functions, perturbation for small B, and numerical integration. Force-displacement characteristics and sheet configurations are found. The results may be applied to sandwiched leaf springs.

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