scholarly journals Generalization of elastohydrodynamic interactions between a rigid sphere and a nearby soft wall

2021 ◽  
Vol 923 ◽  
Author(s):  
Pratyaksh Karan ◽  
Jeevanjyoti Chakraborty ◽  
Suman Chakraborty
Keyword(s):  
Rigid Sphere ◽  
Soft Wall

Abstract

scholarly journals A reconfigurable soft wall-climbing robot actuated by electromagnet

2021 ◽  
Vol 18 (2) ◽  
pp. 172988142199228
Author(s):  
Wendong Zhang ◽  
Wen Zhang ◽  
Zhenguo Sun
Keyword(s):  
Working Conditions ◽  
Horizontal Plane ◽  
Vertical Wall ◽  
Flaw Detection ◽  
Surface Cleaning ◽  
Electromagnetic Actuator ◽  
Climbing Robot ◽  
Soft Wall ◽  
Power Frequency

This article demonstrates a reconfigurable soft wall-climbing robot actuated by electromagnet. The robot follows the earthworm movement gait and is capable of translation, deflection, and rotation movement while working on a sloping ferromagnetic wall. Also the electromagnetic actuator provides a significant improvement in expeditiousness compared with existing actuation modes. The speed of the robot can be adjusted by modulating the power frequency. When the period of motion cycle is 30 ms, the speed is about 26.5 mm s−1, and the robot can rotate with a velocity of 14.1° s−1 on the horizontal plane. It can also climb a vertical wall at the speed of 12.6 mm s−1. The robot is composed of two kinds of modules which can be connected by the magnets embedded. It can also be reconfigured in different working conditions, such as crossing an inaccessible gap, and thus has the potential to be used in flaw detection, surface cleaning, and exploration of ferromagnetic structures.

scholarly journals Design of 3D Additively Manufactured Hybrid Structures for Cranioplasty

Materials ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 181
Author(s):  
Roberto De Santis ◽  
Teresa Russo ◽  
Julietta V. Rau ◽  
Ida Papallo ◽  
Massimo Martorelli ◽  
...  
Keyword(s):  
Physical Models ◽  
Cranial Bone ◽  
Head Model ◽  
Rigid Sphere ◽  
Element Analysis ◽  
Aliphatic Polyesters ◽  
Hybrid Device ◽  
Wide Range ◽  
Hybrid Devices ◽  
Technical Solutions

A wide range of materials has been considered to repair cranial defects. In the field of cranioplasty, poly(methyl methacrylate) (PMMA)-based bone cements and modifications through the inclusion of copper doped tricalcium phosphate (Cu-TCP) particles have been already investigated. On the other hand, aliphatic polyesters such as poly(ε-caprolactone) (PCL) and polylactic acid (PLA) have been frequently investigated to make scaffolds for cranial bone regeneration. Accordingly, the aim of the current research was to design and fabricate customized hybrid devices for the repair of large cranial defects integrating the reverse engineering approach with additive manufacturing, The hybrid device consisted of a 3D additive manufactured polyester porous structures infiltrated with PMMA/Cu-TCP (97.5/2.5 w/w) bone cement. Temperature profiles were first evaluated for 3D hybrid devices (PCL/PMMA, PLA/PMMA, PCL/PMMA/Cu-TCP and PLA/PMMA/Cu-TCP). Peak temperatures recorded for hybrid PCL/PMMA and PCL/PMMA/Cu-TCP were significantly lower than those found for the PLA-based ones. Virtual and physical models of customized devices for large cranial defect were developed to assess the feasibility of the proposed technical solutions. A theoretical analysis was preliminarily performed on the entire head model trying to simulate severe impact conditions for people with the customized hybrid device (PCL/PMMA/Cu-TCP) (i.e., a rigid sphere impacting the implant region of the head). Results from finite element analysis (FEA) provided information on the different components of the model.

An Approach to Parallel Computing in an Eulerian-Lagrangian Two-Phase Flow Model

2002 ◽  
Author(s):  
Marion W. Vance ◽  
Kyle D. Squires
Keyword(s):  
Collision Detection ◽  
Stokes Equations ◽  
Lagrangian Model ◽  
Rigid Sphere ◽  
Dispersed Phase ◽  
Particle Collisions ◽  
Two Phase ◽  
Current Effort ◽  
Index Method ◽  
Parallel Solution

An approach to parallel solution of an Eulerian-Lagrangian model of dilute gas-solid flows is presented. Using Lagrangian treatments for the dispersed phase, one of the principal computational challenges arises in models in which inter-particle interactions are taken into account. Deterministic treatment of particle-particle collisions in the present work pose the most computationally intensive aspect of the simulation. Simple searches lead to algorithms whose cost is O(N2p) where Np is the particle population. The approach developed in the current effort is based on localizing collision detection neighborhoods using a cell-index method and spatially distributing those neighborhoods for parallel solution. The method is evaluated using simulations of the gas-solid turbulent flow in a vertical channel. The instantaneous position and the velocity of any particle is obtained by solving the equation of motion for a small rigid sphere assuming that the resulting force induced by the fluid reduces to the drag contribution. Binary particle collisions without energy dissipation or inter-particle friction are considered. The carrier flow is computed using Large Eddy Simulation of the incompressible Navier-Stokes equations. The entire dispersed-phase population is partitioned via static spatial decomposition of the domain to maximize parallel efficiency. Simulations on small numbers of distributed memory processors show linear speedup in processing of the collision detection step and nearly optimal reductions in simulation time for the entire solution.

scholarly journals NUCLEON RESONANCES AND GPDS IN AdS/QCD

2014 ◽  
Vol 26 ◽  
pp. 1460066 ◽  
Author(s):  
ALFREDO VEGA ◽  
IVAN SCHMIDT ◽  
THOMAS GUTSCHE ◽  
VALERY E. LYUBOVITSKIJ
Keyword(s):  
Roper Resonance ◽  
Wall Model ◽  
Nucleon Resonances ◽  
Soft Wall Model ◽  
Nucleon Spectrum ◽  
Soft Wall

We discuss an holographic soft wall model to describe nucleon properties. We pay special attention to nucleon spectrum, GPDs in the skewness case for nucleons and electroproduction of the N (1440) Roper resonance in soft-wall AdS/QCD.

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