# COMSOL Blog

## Using Cyclic Symmetry to Reduce Computation Time

##### Alexandra Foley | March 17, 2014

When modeling computationally taxing geometries, you can save time by using cyclic symmetry to cut down on memory usage. This can be more complex for rotationally than axially symmetric geometries. However, with the Structural Mechanics Module you can easily solve a single section of an impeller model and still get accurate results.

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### Modeling a Branch Line Coupler

##### Fanny Littmarck | March 14, 2014

Branch line couplers, a type of 90-degree or quadrature hybrid coupler, are popular because they are simple to fabricate and easy to design. They are passive devices commonly used in single-antenna transmitter systems and I/Q signal splitters/combiners. Let’s look at the basics of how this type of coupler works and some of its important design aspects.

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### Enzyme Kinetics, Michaelis-Menten Mechanism

##### Eyal Spier | March 13, 2014

While the mathematical study of chemical reactions has been performed for more than a century, it is only fairly recently that the computational tools for numeric integration of rate equations have been widely available. The old adage of “necessity is the mother of all invention” holds true in this instance. Here, you will find a classical analysis of a non-trivial reaction system, and learn how the simplified solution compares with the “real” one.

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### Benchmark Model Results Agree with Fresnel Equations

##### Lexi Carver | March 12, 2014

Have you ever wondered why boaters wear polarized sunglasses? It’s because sunlight reflecting off the water is primarily polarized in one direction, and polarized sunglasses will block this component of the reflected light, thus reducing glare. To understand why this is, we can use COMSOL software. This example solves the governing Maxwell’s equations using the RF Module or Wave Optics Module to simulate light incident at an angle upon a dielectric medium, and the solution shows agreement with analytic solutions.

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### Defining Curvilinear Coordinates for Anisotropic Materials

##### Nancy Bannach | March 11, 2014

A lot of materials have anisotropic properties and, in many cases, the anisotropy follows the shape of the material. COMSOL Multiphysics offers different methods for defining curvilinear coordinate systems. Here, we discuss the concepts of each and when to use which method.

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### Solutions as Starting Point Values with LiveLink™ for MATLAB®

##### Amelia Halliday | March 10, 2014

There are several techniques out there for saving memory when solving a model. One involves splitting it into separate sections and solving these individually, instead of the entire model at once. If you want to map data from one COMSOL Multiphysics® solution to the next using MATLAB® scripting, you can do so by connecting the two software programs via LiveLink™ for MATLAB®.

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### Buckling, When Structures Suddenly Collapse

##### Henrik Sönnerlind | March 7, 2014

Buckling instability is a treacherous phenomenon in structural engineering, where a small increase in the load can lead to a sudden catastrophic failure. In this blog post, we will investigate some classes of buckling problems and how they can be analyzed.

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### Hybrid Computing: Advantages of Shared and Distributed Memory Combined

##### Jan-Philipp Weiss | March 6, 2014

Previously in this blog series, my colleague Pär described parallel numerical simulations with COMSOL Multiphysics on shared and distributed memory platforms. Today, we discuss the combination of these two methods: hybrid computing. I will try to shed some light onto the various aspects of hybrid computing and modeling, and show how COMSOL Multiphysics can use hybrid configurations in order to squeeze out the best performance on parallel platforms.

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### Plotting Spatial Derivatives of the Magnetic Field

##### Marc Fernandez Silva | March 5, 2014

Being able to compute the spatial gradients of the magnetic field or magnetic flux density is needed in areas such as radiology, magnetophoresis, and geophysics. One of the most important applications is in the design of magnetic resonance imaging machines, where it’s important to analyze not only the field strength, but also the spatial variation of the field. Today’s blog will demonstrate how to compute and plot the gradients of the magnetic field in 3D electromagnetic simulations in COMSOL Multiphysics.

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### Selecting First Gear: Investigating a Classic Car Gearshift Mechanism

##### Gerard Hegemans | March 4, 2014

Cars come with either an automatic gearbox or a manually operated one, a stick shift. With a manual gearbox, we use the stick shifter very frequently while driving the car, yet we hardly ever think about the way the mechanism works. Here, we investigate how it works and what forces are acting on it when submitted to a very common load case — selecting first gear — with the help of a COMSOL Multibody Dynamics model of the gearshift mechanism.

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### PEM Fuel Cell Modeling Examples

##### Mark Fowler | March 3, 2014

Polymer electrolyte membrane or proton exchange membrane (PEM) fuel cells provide a potentially clean and portable source of power. This is of major interest to the transport industry as well as for power generation at fixed sites. COMSOL Multiphysics is a powerful simulation tool you can use to help understand and overcome PEM fuel cell design and construction challenges.

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