Elastic Material Damage of Rotational Atherectomy and Orbital Atherectomy: An in Vitro Assessment

PurposeRotational atherectomy (RA) and orbital atherectomy (OA) are effective procedures for severe calcified coronary artery disease. Nonetheless, vessel perforation remains an adverse complication of these procedures. This study aimed to evaluate factors affecting elastic material damage caused by RA and OA.MethodsAn in vitro assessment was conducted in which the damage to the rubber latex, an elastic material, after RA was evaluated under various conditions, including burr rotational speed (100,000–220,000 rotations per minute), approaching curve, burr size (1.25 mm, 1.75 mm, and 2.0 mm), and fluid viscosity (water and low-molecular weight dextran). Similarly, the rubber latex damage after OA was evaluated in the same experimental system under various conditions, including crown rotational speed, approaching curve, and fluid viscosity.ResultsIn RA, the rubber latex was damaged at lower rotational speeds (p = 0.003), tighter approaching curves (p < 0.0001), and lower fluid viscosity (p = 0.03). In OA, the rubber latex was generally severely damaged.ConclusionA higher rotational speed, coaxial approach for the wall, and higher viscosity contributed to lesser elastic material damage in RA. The safety mechanism for elastic material in OA proved less effective.

Numerical Simulation of the Effect of Repeated Load and Waste Polypropylene on the Behavior of Asphalt Layers

Roads are utilized by many vehicle kinds and heavy vehicles among these may be seen as the most essential for cargo loading, causing paving failure and increasing expenses for rehabilitation and maintenance. In this study, in analyzing a finite element employing Abaqus 6.14, composite effects for wheel loads and temperature were addressed. The asphalt layer was designed as an elastic material, while the base and sub-bases were modeled according to the Mohr coulomb model like an elastic material. And studying the impact of wheel loads on flexible pavement settlement and the main output of analyzing pavement structure is almost represented by the vertical stresses and the surface deformation which are considered as the critical response point. A truck type 2S-2 was tried with two thicknesses of asphalt layer 140 mm and 250 mm and considering that base and subbase layer thicknesses remained constant so it does not affect the variation of displacement. It was found that the increase of asphalt layer thickness from 140 mm to 250 mm leads to a decrease in the vertical displacement of about 0.59% and studied the effect of modified asphalt with polymer and how it effect pavement vertical displacement with an obvious reduction from 0.590 mm to 0.265 mm under the repeated load of 36 ton and The vertical stress decreased from 5.036 kPa to 1.899 kPa

Quasistatic Fracture using Nonliner-Nonlocal Elastostatics with Explicit Tangent Stiffness Matrix

We apply a nonlinear-nonlocal field theory for numerical calculation of quasistatic fracture. The model is given by a regularized nonlinear pairwise (RNP) potential in a peridynamic formulation. The potential function is given by an explicit formula with and explicit first and second derivatives. This fact allows us to write the entries of the tangent stiffness matrix explicitly thereby saving computational costs during the assembly of the tangent stiffness matrix. We validate our approach against classical continuum mechanics for the linear elastic material behavior. In addition, we compare our approach to a state-based peridynamic model that uses standard numerical derivations to assemble the tangent stiffness matrix. The numerical experiments show that for elastic material behavior our approach agrees with both classical continuum mechanics and the state-based model.The fracture model is applied to produce a fracture simulation for a ASTM E8 like tension test. We conclude with an example of crack growth in a pre-cracked square plate. For the pre-cracked plate, we investigated {\it soft loading} (load in force) and {\it hard loading} (load in displacement). Our approach is novel in that only bond softening is used as opposed to bond breaking. For the fracture simulation we have shown that our approach works with and without initial damage for two common test problems.

The Influence of Voids in the Vibrations of Bodies with Dipolar Structure

In our study we analyse the vibration of a right cylinder which consists of an elastic material with dipolar structure and has pores. One end of this cylinder is subjected to an excitation, harmonically in time. The other end of the cylinder and its lateral surface are free of loads. We prove that the presence of the voids does not affect the spatial decay of effects away from the excited end, if the harmonic excitation level is below a predetermined threshold.

Designing a Partly Self-Powered Keyboard Based on Triboelectric Effect

The purpose of this paper is to design a keyboard using the triboelectric effect (Tribo Electric Nano Generator - TENG) to collect a part of the energy from keystrokes to reduce the power consumption of the keyboard. Using elastic material as the cover on the keyboard to maximize the capture of energy from typing. The keyboard layers are made from common materials such as Al (Aluminum) and PTFE (Polytetrafluoroethylene). The built-in 16-button keyboard ensures the same typing speed as a typical keyboard. Based on selected triboelectric material, the output voltage of keyboard was simulated and processed by using a signal detection circuit. The results show that the average voltage generated by each key with electrical friction effect is about 4 V, the power consumption for the detection circuit is about 0.32 W. In addition, the keystroke signals were sent and displayed correctly on the designed software on the computer.