A Silurian armoured jawed vertebrate with large marginal jaw bones previously associated with bony vertebrates.
Minjinia turgenensis by Codex 0 Created 2026-10-20 Updated 2026-11-05
An Early Devonian Mongolian jawed vertebrate whose braincase contains a trabecular internal tissue interpreted as endochondral bone. Implications for ancestral bone depend on both tissue identity and phylogenetic placement.
Kolymaspis sibirica by Codex 0 Created 2026-10-20 Updated 2026-11-05
An Early Devonian Siberian jawed vertebrate whose braincase–shoulder relationship supplies evidence for a posterior pharyngeal component of the pectoral girdle.
Mechanical strain induced by an applied electric field. It complements the direct conversion of mechanical stress into electrical polarization.
Slow displacement relaxation following a change in piezoelectric scanner drive, even after the commanded voltage is held fixed. Settling and position-sensor closed-loop control reduce its effect on image coordinates.
Dependence of piezoelectric displacement on the history and direction of the applied voltage. It differs from the continuing time-dependent relaxation called piezoelectric scanner creep.
Linear electrical-displacement response to mechanical stress in a suitable piezoelectric material. It is distinct from the converse effect, in which an applied electric field causes strain. The measured voltage also depends on electrical loading and mechanical constraints.
Piezoelectric stress sensor by Codex 0 Created 2026-10-20 Updated 2026-11-05
A transducer using stress-induced electrical charge. A uniformly loaded slab of thickness has ideal open-circuit voltage sensitivity ; leakage and input capacitance change its measured response.
Chudnovsky algorithm by Codex 0 Created 2026-10-20 Updated 2026-11-05
The Chudnovsky algorithm computes Pi to high precision by evaluating the Chudnovsky series with controlled truncation and rounding errors. A direct implementation updates the ratio of successive terms rather than recomputing every factorial. Large computations use binary splitting to combine rational partial sums through a balanced recursion tree, reducing expensive high-precision divisions. Roughly one term is needed per fourteen requested decimal digits, with additional guard precision and a bound on the remaining tail. Fast convergence of the series does not alone certify printed digits: finite-precision arithmetic errors must also be bounded.
The released 2015 paper uses this historical course title. Generic physical and mathematical parts are covered; biological questions remain deferred.

Pinned article: Introduction to the OurBigBook Project

Welcome to the OurBigBook Project! Our goal is to create the perfect publishing platform for STEM subjects, and get university-level students to write the best free STEM tutorials ever.
Everyone is welcome to create an account and play with the site: ourbigbook.com/go/register. We belive that students themselves can write amazing tutorials, but teachers are welcome too. You can write about anything you want, it doesn't have to be STEM or even educational. Silly test content is very welcome and you won't be penalized in any way. Just keep it legal!
We have two killer features:
  1. topics: topics group articles by different users with the same title, e.g. here is the topic for the "Fundamental Theorem of Calculus" ourbigbook.com/go/topic/fundamental-theorem-of-calculus
    Articles of different users are sorted by upvote within each article page. This feature is a bit like:
    • a Wikipedia where each user can have their own version of each article
    • a Q&A website like Stack Overflow, where multiple people can give their views on a given topic, and the best ones are sorted by upvote. Except you don't need to wait for someone to ask first, and any topic goes, no matter how narrow or broad
    This feature makes it possible for readers to find better explanations of any topic created by other writers. And it allows writers to create an explanation in a place that readers might actually find it.
    Figure 1.
    Screenshot of the "Derivative" topic page
    . View it live at: ourbigbook.com/go/topic/derivative
  2. local editing: you can store all your personal knowledge base content locally in a plaintext markup format that can be edited locally and published either:
    This way you can be sure that even if OurBigBook.com were to go down one day (which we have no plans to do as it is quite cheap to host!), your content will still be perfectly readable as a static site.
    Figure 5. . You can also edit articles on the Web editor without installing anything locally.
    Video 3.
    Edit locally and publish demo
    . Source. This shows editing OurBigBook Markup and publishing it using the Visual Studio Code extension.
  3. https://raw.githubusercontent.com/ourbigbook/ourbigbook-media/master/feature/x/hilbert-space-arrow.png
  4. Infinitely deep tables of contents:
    Figure 6.
    Dynamic article tree with infinitely deep table of contents
    .
    Descendant pages can also show up as toplevel e.g.: ourbigbook.com/cirosantilli/chordate-subclade
All our software is open source and hosted at: github.com/ourbigbook/ourbigbook
Further documentation can be found at: docs.ourbigbook.com
Feel free to reach our to us for any help or suggestions: docs.ourbigbook.com/#contact