The chaos machine: analogue computing rediscovered (1)

Analogue computers provide actual rather than virtual representations of model systems. They are powerful and engaging computing machines that are cheap and simple to build. This two-part Retronics article helps you build (and understand!) your own analogue computer to simulate the Lorenz butterfly that's become iconic for Chaos theory

Analysis of hypersonic pressure and heat transfer tests on a flat plate with a flap and a delta wing with body, elevons, fins, and rudders Final report

Hypersonic boundary layer separation and flow field interference analysis during Dyna-Soar space glider testin

Minimizing Chaos

The thesis works presented in this paper are mixed media paintings that explore the tension between artistic control and abandon in what is essentially an intuitive driven process of image making. With these thesis works I have sought to use additive and subtractive processes to create compositions that are as much an exploration of materials as they are an exploration of the formal elements of art. My work is focused on recreating the patterns, textures, and surfaces found in man-made objects and environments that I find in my daily life and I believe are often overlooked in their aesthetic value. In doing so, I hope to recreate for the viewer the moments of aesthetic discovery that I have found within the patterns, textures, and surface qualities of these objects

Quantifying the Effect of Non-Larmor Motion of Electrons on the Pressure Tensor

In space plasma, various effects of magnetic reconnection and turbulence cause the electron motion to significantly deviate from their Larmor orbits. Collectively these orbits affect the electron velocity distribution function and lead to the appearance of the "non-gyrotropic" elements in the pressure tensor. Quantification of this effect has important applications in space and laboratory plasma, one of which is tracing the electron diffusion region (EDR) of magnetic reconnection in space observations. Three different measures of agyrotropy of pressure tensor have previously been proposed, namely, $A\varnothing_e$, $D_{ng}$ and $Q$. The multitude of contradictory measures has caused confusion within the community. We revisit the problem by considering the basic properties an agyrotropy measure should have. We show that $A\varnothing_e$, $D_{ng}$ and $Q$ are all defined based on the sum of the principle minors (i.e. the rotation invariant $I_2$) of the pressure tensor. We discuss in detail the problems of $I_2$-based measures and explain why they may produce ambiguous and biased results. We introduce a new measure $AG$ constructed based on the determinant of the pressure tensor (i.e. the rotation invariant $I_3$) which does not suffer from the problems of $I_2$-based measures. We compare $AG$ with other measures in 2 and 3-dimension particle-in-cell magnetic reconnection simulations, and show that $AG$ can effectively trace the EDR of reconnection in both Harris and force-free current sheets. On the other hand, $A\varnothing_e$ does not show prominent peaks in the EDR and part of the separatrix in the force-free reconnection simulations, demonstrating that $A\varnothing_e$ does not measure all the non-gyrotropic effects in this case, and is not suitable for studying magnetic reconnection in more general situations other than Harris sheet reconnection.Comment: accepted by Phys. of Plasm

Vertebrate Damage Management: The Future of an Evolving Profession

The author argues that an objective of a new group of people taking a systems approach to large wild animal problems should be to manage damage as a cost-reducing role within a total, profitable, long-term system, not necessarily to control the pest. The needs are for well-grounded financial analyses both for customers, the public, the resources, and the well-being of the profession. A point of view is advanced for the need for evolving pest-related operations into a new, unique profession that is involved in a profound way as an element of a cost-effective total land and human resource production system