scholarly journals Optically-excited simultaneous photoacoustic and ultrasound imaging based on a flexible gold-PDMS film

2020 ◽  
Vol 13 (04) ◽  
pp. 2050012
Author(s):  
Dandan Cui ◽  
Zhenhui Zhang ◽  
Yujiao Shi
Keyword(s):  
Laser Energy ◽  
Cost Effective ◽  
Light Transmittance ◽  
Center Frequency ◽  
Incident Laser ◽  
Element Analysis ◽  
Pdms Film ◽  
Incident Laser Energy ◽  
The Finite Element Analysis ◽  
The Us

We constructed a flexible gold-polydimethylsiloxane (gold-PDMS) nanocomposites film with controllable thickness and light transmittance, to realize optically-excited simultaneous photoacoustic (PA) and ultrasound (US) imaging under a single laser pulse irradiation. Benefiting from the excellent thermoelastic properties, the gold-PDMS film absorbs part of the incident laser energy and produces a high-intensity US, which is used to realize US imaging. Meanwhile, the partly transmitted light is used to excite samples for PA imaging. By controlling the thickness of the gold-PDMS, we can control the center frequency in the US imaging. We experimentally analyzed the frequency of the produced US signal by the gold-PDMS film and compared it with the finite element analysis (FEA) method, where the experiments agree with the FEA results. This method is demonstrated by the experiments on phantoms and a mouse model. Our work provides a cost-effective methodology for simultaneous PA and US imaging.

FSI Methodology for Analyzing VIV on Subsea Piping Components With Practical Boundary Conditions

2013 ◽  
Author(s):  
Marcus Gamino ◽  
Samuel Abankwa ◽  
Raresh Pascali
Keyword(s):  
Boundary Conditions ◽  
Three Dimensional ◽  
Cost Effective ◽  
General Assumption ◽  
Computational Simulations ◽  
Element Analysis ◽  
Structure Interaction ◽  
The Finite Element Analysis ◽  
Computational Fluid Dynamics Cfd ◽  
Computational Methodology

A general assumption in performing vortex-induced vibration (VIV) analysis of pipeline free spans is both ends of the free span are fixed and/or pinned in order to simplify computational simulations; however, DNV Recommended Practice F105 states that these boundary conditions must adequately represent the pipe-soil interaction and the continuality of the pipeline. A computational methodology is developed to determine the effects of pip-soil interaction at the ends of a free span. Three-dimensional fluid-structure interaction (FSI) simulations are performed by coupling the computational fluid dynamics (CFD) codes from STAR-CCM+ with the finite element analysis (FEA) codes from ABAQUS. These FSI simulations in combination with separate coupled Eulerian-Lagrangian (CEL) simulations are modeled to mimic real word conditions by setting up boundary conditions to factor in the effects of pipe-soil interaction at the ends of the span. These simulations show a mitigation of overall stresses to the free spans; as a result, the integration of pipe-soil interaction in free span assessment may prove cost effective in the prevention of unnecessary corrective action.

scholarly journals The Usage of the Johnson-Cook Constitutive Model in the Finite Element Analysis of the Caulking Process

2019 ◽  
Vol 290 ◽  
pp. 03013
Author(s):  
Claudiu Rodean ◽  
Livia-Dana Beju ◽  
Gabriela Rusu ◽  
Mihai Popp
Keyword(s):  
Finite Element Analysis ◽  
Plastic Deformation ◽  
World Wide ◽  
Cost Effective ◽  
Element Analysis ◽  
Plastic Deformations ◽  
Current State ◽  
The Finite Element Analysis ◽  
Cost Efficient ◽  
Deformation Models

The present paper highlights the importance of generating a model for analysing the caulking process. The caulking operation is a fast, cost-efficient, cost-effective way of assembling, which is currently less studied in world-wide papers. The operation is at the border between plastic deformation and cutting process. It is therefore necessary to create a model to describe the process. In the paper are presented the main examples of applications, the main parameters that characterize the process, the current state of the cutting and plastic deformation models. After the analysis we concluded that the most valuable model for describing plastic deformations is the Johnson-Cook model. This information is the basis for developing a model for describing the caulking process.

Analysis of Stress and Strain Distribution in a Vehicle Wheel: Finite Element Analysis Versus the Experimental Method

2005 ◽  
Vol 40 (6) ◽  
pp. 513-523 ◽  
Author(s):  
J Stearns ◽  
T S Srivatsan ◽  
X Gao ◽  
A Prahash ◽  
P. C Lam
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Cost Effective ◽  
Stress And Strain ◽  
Inflation Pressure ◽  
Element Analysis ◽  
Vehicle Load ◽  
Cost Effective Approach ◽  
The Finite Element Analysis ◽  
Stress And Strain Distribution

An extensive finite element analysis of a vehicle wheel subject to the conjoint influence of inflation pressure and radial load (vehicle load) is reported in this paper. The commonly used design considerations in an automotive wheel are presented and discussed. A method for determining the load(s) transmitted from the vehicle to the wheel is detailed and the intrinsic influence of inflation pressure on wheel performance is discussed. The finite element results are compared with experimental measurements of strain obtained using strain gauges. The salient advantage of the finite element analysis as an attractive and cost-effective approach to the design and analysis of vehicle wheels is elaborated.

Laser Assisted E-Beam Epitaxial Growth of Si/Ge Alloys on Si

1990 ◽  
Vol 202 ◽  
Author(s):  
Paul Martin Smith ◽  
S. Lombardo ◽  
M.J. Uttormark ◽  
Stephen J. Cook ◽  
Michael O. Thompson
Keyword(s):  
Film Thickness ◽  
Epitaxial Growth ◽  
Room Temperature ◽  
Laser Energy ◽  
Incident Laser ◽  
Fine Grained ◽  
Surface Mobility ◽  
Incident Laser Energy ◽  
Enhanced Surface ◽  
Xecl Excimer Laser

ABSTRACTA novel laser-assisted technique for e-beam epitaxial growth of GexSi1−x alloys on <100> Si has been investigated. During deposition, a XeCl excimer laser is used to either heat, or to melt and crystallize, the GexSi1−x continuously as the material is evaporated. This process of heating or melting and crystallizing can be continued until the desired film thickness is achieved. At incident laser energy densities which produce melt, the underlying crystalline seed ensures epitaxial growth during the subsequent solidification. Depositions of films up to 3 at.% Ge under this liquid regime, with substrates held nominally at room temperature, exhibited complete epitaxial growth. At energy densities below the melt threshold, enhanced surface mobility for epitaxial alignment is required. Depositions in this regime exhibit only partial epitaxial growth with conversion to fine grained polycrystalline growth after short distances.

The effect of incident laser energy on pulsed laser deposition of HgCdTe films

2009 ◽  
Vol 311 (4) ◽  
pp. 1087-1090 ◽  
Author(s):  
Mei Liu ◽  
Baoyuan Man ◽  
Xingchao Lin ◽  
Xiangyang Li
Keyword(s):  
Pulsed Laser Deposition ◽  
Laser Energy ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Incident Laser ◽  
Incident Laser Energy

Raman Spectroscopy on Individual Identified Carbon Nanotubes

2012 ◽  
Vol 1407 ◽  
Author(s):  
R. Parret ◽  
D. Levshov ◽  
T. X. Than ◽  
D. Nakabayashi ◽  
T. Michel ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Laser Energy ◽  
Low Frequency ◽  
Radial Breathing Mode ◽  
Incident Laser ◽  
Mechanical Coupling ◽  
Incident Laser Energy ◽  
Double Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

ABSTRACTIn this paper, we discuss the low-frequency range of the Raman spectrum of individual suspended index-identified single-walled (SWCNTs) and double-walled carbon nanotubes (DWCNTs). In SWCNTs, the role of environment on the radial breathing mode (RBM) frequency is discussed. We show that the interaction between the surrounding air and the nanotube does not induce a RBM upshift. In several DWCNTs, we evidence that the low-frequency modes cannot be connected to the RBM of each related layer. We discuss this result in terms of mechanical coupling between the layers which results in collective radial breathing-like modes. The mechanical coupling qualitatively explains the observation of Raman lines of radial breathing-like modes, whenever only one of the layers is in resonance with the incident laser energy.

Research on Propagation Characteristics of SAW Based on ANSYS

2013 ◽  
Vol 798-799 ◽  
pp. 634-637
Author(s):  
Chang Bao Wen ◽  
Xin Xu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Element Model ◽  
Substrate Material ◽  
Center Frequency ◽  
Propagation Characteristics ◽  
Element Analysis ◽  
Piezoelectric Crystals ◽  
Geometry Model ◽  
The Finite Element Analysis

In order to get the propagation characteristics of surface acoustic wave (SAW) along the piezoelectric crystals surface, the scheme of achieving the propagation characteristics of SAW device based on finite element analysis with ANSYS was proposed in this paper. In this scheme, the model of SAW device was built by the finite element analysis, and the parameter of the electrode and the substrate material was set. The geometry model of SAW device was meshed, and the continuous entity was divided into finite element model. The actual problems of boundary conditions and load in mechanical and electrical were applied to the model. By means of simulating a SAW device with center frequency at 100 MHz, the comparison and analysis between the simulation results and the theory results were presented. Experiments results confirm that the SAW energy is confined into a zone close to the piezoelectric crystals surface and is 1 to 2 wavelengths thick, and the amplitude and energy of the SAW will decrease rapidly with increasing depth.

scholarly journals Numerical modeling of quantum beam generation from ultra-intense laser-matter interactions

2015 ◽  
Vol 33 (2) ◽  
pp. 151-155 ◽  
Author(s):  
Tatsufumi Nakamura ◽  
Takehito Hayakawa
Keyword(s):  
Energy Transport ◽  
Laser Energy ◽  
Radiation Reaction ◽  
High Energy ◽  
Intense Laser ◽  
Incident Laser ◽  
Particle In Cell ◽  
Transport Code ◽  
Incident Laser Energy ◽  
Good Agreement

AbstractWhen intense laser beams interact with solid targets, high-energy photons are effectively generated via radiation reaction effect. These photons receive a large portion of the incident laser energy, and the energy transport by photons through the target is crucial for the understanding of the laser–matter interactions. In order to understand the energy transport, we newly developed a Particle-in-Cell code which includes the photon–matter interactions by introducing photon macro-particles. Test simulations are performed and compared with simulations using a particle transport code, which shows a good agreement.

Angular Distribution and Ion Time of Flight Produced on Silicon Target by Laser Irradiation

2011 ◽  
Vol 227 ◽  
pp. 31-34
Author(s):  
Yasmina Belaroussi ◽  
Tahar Kerdja ◽  
Smail Malek
Keyword(s):  
Angular Distribution ◽  
Laser Energy ◽  
Angular Distributions ◽  
Physical Processes ◽  
Incident Laser ◽  
Ion Energy ◽  
Incident Laser Energy ◽  
Silicon Target ◽  
The Mean

The growth of thin films by laser ablation involves very complex physical processes. The quality of the layer and stoechiometry of the deposits depend on key parameters like the ion energy and their angular distribution. The evolution of ions number and energy, and the angular distributions in regards to the incident laser energy, have been studied by the mean of a charges collector. We present the polar diagrams of energy and number of ions collected by irradiating a silicon target using an excimer laser at different energies.

Shadowgraph of Pulse CO2 Laser Induced Breakdown in Different Pressure Air

2014 ◽  
Vol 887-888 ◽  
pp. 1001-1004 ◽  
Author(s):  
Yu Zhang ◽  
Duan Yong Li ◽  
Tao Wu
Keyword(s):  
Shock Wave ◽  
Delay Time ◽  
High Speed ◽  
Laser Energy ◽  
Early Stage ◽  
Propagation Speed ◽  
Air Pressure ◽  
Incident Laser ◽  
Incident Laser Energy ◽  
Laser Induced Breakdown

The expansion property of an infrared CO2 laser produced air plasma is characterized using a high-speed imaging shadowgraph technique. The shadowgraphs were taken by a time-gated intensified charge-coupled device at various delay times after single pulses induced gas breakdown. We examined five incident laser energy of 180, 240, 345, 420 and 600 mJ induced air breakdown at the pressure of atmospheric and 104 Pa. A shock wave produced by laser induced breakdown was also observed and its speed was measured as a function delay time between the breakdown and the shadow imaging under different air pressure. The experimental results indicated that the radial and axial shock wave front evolutions showed similar behavior, which increased fast with delay time at early stage and slowly at later stage. The propagation speed of the wavefront was about 2 cm/μs at the initial stage of breakdown, and then decreased very quickly. The propagation speed under low air pressure was higher than that of gases under high pressure and the spark sustained less time at lower pressure. The size of laser induced air spark increased with incident laser energy but not simple linear relationships.

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