Using Simulation to Study Ultrasound Focusing for Clinical Applications

Guest Thomas Clavet August 31, 2017

Today, guest blogger Thomas Clavet of EMC3 Consulting, a COMSOL Certified Consultant, discusses simulating phased array and geometrically focused probes. Ultrasound focusing is widely used in various industrial applications, such as nondestructive testing (NDT) and medical imaging. For clinical applications, high-intensity focused ultrasound (HIFU) is a specific aspect of this technology where most of the power provided by the probe is carried to a targeted zone to coagulate biological tissues. This blog post discusses ultrasound focusing simulation.

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Brianne Costa August 30, 2017

“I think I can safely say that nobody understands quantum mechanics.” — Richard Feynman, in The Character of Physical Law (1965). Although the Nobel-prize-winning physicist might have been speaking in jest, quantum mechanics is a difficult concept to teach — and simulate. Modeling a double-barrier structure in the COMSOL Multiphysics® software can help teach quantum mechanics concepts to physics students as well as enhance the research and development of semiconductor devices.

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Bridget Cunningham August 14, 2017

Compliance testing is used to ensure that various products, processes, and systems meet standard requirements. Just as important as these tests is the equipment used to perform them. This testing equipment must be designed so that it delivers precise measurements that are reflective of real-world performance. RF modeling is a useful approach to analyzing and optimizing such devices, generating greater confidence in the measurements they obtain. To showcase this, we’ll look at a well-known equipment choice in EMC/EMI testing…

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Caty Fairclough August 9, 2017

Studying vacuum system designs can be difficult, since some analysis methods only work when the relative speed of the gas molecules is very large compared to the velocity of the enclosing walls. This is not the case for turbomolecular pumps, which we can model and analyze using a Monte Carlo approach and the Rotating Frame feature in the COMSOL Multiphysics® software. Let’s check out one example below.

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Bjorn Sjodin August 8, 2017

The latest version of the AC/DC Module enables you to create electrostatics models that combine wires, surfaces, and solids. The technology is known as the boundary element method and can be used on its own or in combination with finite-element-method-based modeling. In this blog post, let’s see how the new functionality can be used to conveniently set up a model that includes a number of very thin spiral wires.

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Bridget Cunningham August 3, 2017

There are many ways to improve the frequency response of frequency-selective surfaces. However, optimizing these structures can require multiple steps. Every change to a design parameter — unit cell type, polarization, substrate properties, etc. — needs the expertise of simulation engineers. Simulation apps enable those with little or no simulation experience to run analyses for their specific stage of the design process on their own.

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Bridget Cunningham August 1, 2017

Helmholtz coils are used by scientists to generate uniform magnetic fields to study electromagnetism and its characteristics. These devices are used in MRI, spectroscopy, magnetoresistance measurements, and equipment calibrations. Here, we’ll look at what Helmholtz coils are, why they are important, and using a simulation-based approach to their design.

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Peter Yakubenko July 26, 2017

Many elongated structures can be modeled effectively using 2D representations of their cross sections. A typical assumption is the plane strain approximation, which implies that all out-of-plane strain components are zero. This assumption is valid when the out-of-plane deformation is restrained; for example, when the ends of the structure are fixed. However, in many cases, the structure is free to expand in the out-of-plane direction. Let’s discuss how to model this case, which is sometimes called generalized plane strain.

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Jiyoun Munn July 19, 2017

When simulating electromagnetic devices, a common mistake is putting everything into a model at the same time, including a complicated geometry, complex material properties, and a mixed bag of boundary conditions. This makes the model run for a long time and you might get frustrated when your simulation results are physically wrong, without any clues as to why. Today, we will discuss how to efficiently set up simple RF, microwave, and millimeter-wave circuit models in the COMSOL Multiphysics® software.

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Bridget Cunningham July 17, 2017

On the morning of March 22, 2006, NASA launched their Space Technology 5 mission. For about three months, miniaturized satellites explored Earth’s magnetic fields collecting high-quality measurements. Beyond gathering scientific data, the mission represents a turning point. Instead of large traditional satellite missions, miniaturized technology is taking precedence in space exploration. And within these systems, MEMS technology could serve as a means of active thermal control. Further improvements are already taking shape with the help of multiphysics simulation.

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Annette Pahl July 5, 2017

Plasma modeling normally requires knowing the electron energy distribution function (EEDF) as well as transport properties like electron mobility and diffusivity. To accurately calculate these quantities with the Boltzmann equation, we must also know the electron density (and possibly the density of all species subject to electron impact reactions). However, the electron (and species densities) are outputs of a plasma model, resulting in a catch-22. Let’s take a look at how to overcome this challenge using an example app.

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