Main Page of David I. Feinstein

In my years at Boeing, and then at Micromonitors, a high technology start–up company, and finally as a consultant, I have found a niche in the world outside academia. That niche is in problem formulation, which is the place where you conceive a data representation and derive the equations that characterize a situation.

My Resume

Some Interesting Problems in Physics & Applied Mathematics

Though often unappreciated, interesting scientific problems happen all the time in industry! Here are some nifty ones which I have had the pleasure of addressing.

An array of sensors, organized as a grid of unit squares of thickness h, responds to impinging cosmic rays. The cosmic rays follow line trajectories that may intercept more than one sensor of the array, giving the appearance of cross–talk. A surprisingly large fraction of isotropically & uniformly distributed cosmic rays excite cross–talk.

The intriguing kinematics of motion around a circle at increasing speed when the direction of thrust is adjustable but its magnitude is fixed.

The temperature distribution around a moving heat source.

Sometimes, the problems that arise suggest questions in mathematics and physics that are of independent interest:

Asking for coordinate transformations under which the wave equation remains invariant yields uniquely the Lorentz transformation of Special Relativity.

Solid angle is ordinarily defined via a surface integral. Intuitively, only the bounding perimeter of the surface is necessary to determine the solid angle it subtends. Expressing solid angle as a line integral reveals its connection to curvature.