# COMSOL Blog

## Tuning an Orchestra with the Help of Multiphysics Simulation

##### Bethany Nine | August 14, 2013

Multiphysics applications are all around us. Consider, for example, a setting where science may be the last thing on our minds: a music concert. You might be enjoying the slight sinusoidal variations in atmospheric pressure we call sound waves, or music, but those pressure variations must come from somewhere. In fact, they are due to a multiphysics effect where sinusoidal structural vibrations in an object disturb the surrounding air, causing pressure variations in the air that then propagate outward and […]

### Save with COMSOL Conference 2013 Group Discounts

##### Lauren Sansone | August 13, 2013

If your colleagues are interested in joining you for the COMSOL Conference 2013, you might want to consider the Group Discount. Discounted rates are available at each of the three COMSOL Conference locations — Boston, Bangalore, and Rotterdam. This way, you and your colleagues can get all the training you need in one place, at the fraction of the fee as compared to registering one-by-one.

### Specific Absorption Rate (SAR) in the Human Brain

##### Fanny Littmarck | August 12, 2013

It seems everyone and their kid brother has a cell phone these days — and we are constantly using them. We don’t just rely on them to make calls anymore, either; they serve as our maps, calendars, to-do lists, channel for social interaction, and so forth. This continuous use begs the question: “What about the radiation our phones emit, and how much of it is absorbed by our brains?” When considering this, scientists use the specific absorption rate (SAR) to […]

### Inertial Focusing, a Counterintuitive Approach to Concentrate Cells

##### Matheus Fernandes | August 9, 2013

Suppose we have a rectangular microchannel containing a laminar flow with Reynolds number Re = 1. Next, let’s randomly distribute suspended particles at the channel’s inlet. Given that there are no external forces acting on these particles, you would intuitively expect that the particles would trace the fluid streamline. However, scientists from Massachusetts General Hospital (MGH) and Veryst Engineering would disagree, and their research findings suggest a completely different pattern than what would be expected. The researchers claim that depending […]

### Simulating Pesticide Runoff, the Effects of Aldicarb

##### Alexandra Foley | August 8, 2013

When pesticides are used in crops to control pests, their effects on the environment continue even after they have served their purpose. Pesticides can leach into the soil and water sources that both humans and animals depend on, spreading harmful chemicals to the surrounding ecosystem. Over time, their active ingredients are detoxified through different reactions that occur after their release, eventually degrading them into harmless products. Understanding the pesticide runoff patterns and mobility of various pesticides before and after they […]

### Turbine Stator Blade Cooling and Aircraft Engines

##### Stephan Savarese | August 7, 2013

Technology and mechanics enthusiasts might agree that engines are very cool — and they also know how fussy they get when running into cooling problems. When it comes to aircraft propulsion, overheating is not an option. Most planes can’t fly safely without an engine, so why run the risk of overheating? While current engine designs limit that risk using clever cooling systems, another path to solve this problem would be to design more energy-efficient engines, exempt from excessive heat release. […]

### How to Implement a Mesh Refinement Study

##### Bethany Nine | August 6, 2013

A couple of weeks ago, I led a webinar on postprocessing and visualization features in COMSOL Multiphysics. This webinar was very popular among COMSOL users, so I wanted to follow up with a blog post to highlight one of the important topics we covered — performing a mesh refinement study in COMSOL Multiphysics.

### Lam Research on Simulation of Wafer Fabrication and Moore’s Law

##### Bernt Nilsson | August 5, 2013

We have come to take for granted the ever-increasing performance gains in computational power. Enabled by advances in semiconductor processing techniques, we reap the benefits from exciting new features in everything from smartphones to workstations. The good news for all of us is that the semiconductor industry is steaming ahead, relentlessly pushing the limits of wafer fabrication. Each year, a new generation of sophisticated fabrication equipment is developed. Features etched on silicon are now at the atomic scale. In the […]

#### Article Categories

##### Walter Frei | August 2, 2013

The COMSOL Optimization Module includes both gradient-based and gradient-free optimization techniques. Whereas the gradient-based optimization method can compute an exact analytic derivative of an objective function and any associated constraint functions, it does require these functions to be smooth and differentiable. In this blog post, we examine the use of the gradient-free optimizer, which can consider objective function and constraints that are not differentiable or smooth. The dimensions of a spinning wheel are optimized to reduce the mass while maintaining […]

### Simulating the Freeze-Drying Process

##### Alexandra Foley | August 1, 2013

When thinking about freeze-drying processes, I am reminded of astronaut food like the freeze-dried ice cream I tried as a kid. While this application of freeze-drying is important for preserving food being launched into space, there is also an incredible number of noteworthy applications that are used a little closer to home. Let’s take a look at the freeze-drying process, how it can be simulated, and some of the products and designs that rely on it to function.