INKTOBER DAY 13 To 21!!!  #21 DRAIN #20 BREAKABLE #19 SCORCHED #18 BOTTLE #17 SWOLLEN #16 ANGULAR #15

Mathematics, rightly viewed, possesses not only truth, but supreme beauty- a beauty cold and austere, without the gorgeous trappings of painting or music.

Bertrand Russell

(via spring-of-mathematics)

Figurilla en Forma de Rana

La pequeña pieza elaborada en oro, con incrustaciones de turquesa a manera de ojos, procede de Chichén Itzá y seguramente poseía un especial simbolismo por el estrecho vinculo existente entre los anfibios, las deidades y el inframundo.

INAH

Zany zebra facts: 1) Each zebra has a unique stripe pattern—no two are alike. 2) A zebra’s eyesight at night is thought to be about as good as that of an owl. 3) Zebras have a pad of fat under their mane that keeps it standing straight up.

Thanks to Todd Lahman for the stunning shot of Zari the zebra.

Entelodonts: terrifying.

Shown here compared to a modern pig skull on the left. (Entelodonts were actually more closely related to whales and hippos than pigs.)

Here is a semester project in the 2012 Mechatronic control systems engineering module at San Jose State University. This is a Proportional-Integral-Derivative controlled (PID), 6 degree of freedom (6-DOF) Stewart platform, which basically means it has six axes on the top plate. This prototype uses 6 radio controlled servo motors instead of the traditional use of hydraulic jacks or electronic actuators. (this video has sound)

Proportional-Integral-Derivative:

A PID controller continuously calculates an error value as the difference between a measured process variable and a desired setpoint. The controller attempts to minimize the error over time by adjustment of a control variable, such as the position of a set of servo motors or actuators,  to a new value, given by a weighted sum:

where Kp ,Ki , and Kd, all non-negative, denote the coefficients for the proportional, integral, and derivative terms, respectively (sometimes denoted P, I, and D).

P accounts for present values of the error , and is determined by the direction and magnitude the correction needs to be applied (e.g. if the error is large and positive, the control variable will be large and negative),

I accounts for past values of the error (e.g. if the output is not sufficient to reduce the size of the error, the control variable will accumulate over time, causing the controller to apply a stronger action through P), and

D accounts for possible future values of the error, based on its current rate of change. This part determines when and at what rate it needs to reduce the magnitude of its action, e.g as the ball fast approaches the desired set point at the centre of the plate.

[source]

Ammonites on Matrix (Quenstedtoceras sp., Jurassic) - Volga River, Ulyanovsk, Russia

This extremely artistic assemblage of large and small ammonites from Russia demonstrate an intense iridescence and highlights due to the presence of metallic Pyrite. The cluster has been positioned on a new matrix, as the grainy rock in which these Quenstedtoceras cephalopods were collected is not hard nor stable enough to display them permanently. The added component is an attractive piece of what is known as septarian, a mud-like material that grows in nodules. In this instance, yellowish Calcite crystals and gray sediment have formed the rock on which these colorful ammonites reside. The cluster is quite representative of the Volga River material, and that combination results in a dramatic display specimen.

Overall Measurements: 6.30 x 5.51 x 5.71 inches (16.00 x 14.00 x 14.50 cm)

Cute animals ♥

Gray wolves by Chad Barry

The “Squidworm” is believed to be a transitional organism from benthic worms to free-swimming pelagic worms.  They are named Squidworms due to their tentacle-like branchiae and palps.

(source)