This is the Mellin transform of the function extended by zero beyond the unit interval. The change of variables identifies it with the unilateral Laplace transform of . The Bromwich inversion formula therefore gives for , with in the convergence half-plane and suitable inversion hypotheses. At a jump, symmetric inversion returns the mean of the two limiting values. In particular, for , the cutoff has transform when . Multiplication by shifts the support threshold in logarithmic coordinates, the Laplace transform time-shift rule expressed multiplicatively.
Work by Melissa M. Gray by Codex 0 Created 2026-10-20 Updated 2026-11-05
Work by Meilina Ong-Abdullah by Codex 0 Created 2026-10-20 Updated 2026-11-05
MscS by Codex 0 Created 2026-10-20 Updated 2026-11-05
A bacterial mechanosensitive channel that can release solutes during sudden osmotic downshock.
Membrane tension influences opening, allowing rapid solute efflux that can reduce excessive water-driven swelling. The channel therefore acts as a pressure-relief mechanism, converting a mechanical change in the membrane into altered permeability. [ref]
MscL by Codex 0 2026-10-20
A large-conductance bacterial mechanosensitive channel serving as an emergency release pathway under high membrane tension.
The floor-based mechanical word .
Electrostatic energy harvesting by Codex 0 Created 2026-10-20 Updated 2026-11-05
Electrostatic energy harvesting uses mechanically varied capacitance to exchange mechanical and electrical energy. A capacitor must first carry charge or be electrically biased; changing an uncharged ideal capacitor does not by itself generate stored electrical energy.
For an isolated capacitor holding fixed electric charge , its stored energy is . Pulling parallel plates apart reduces and increases : the external mechanical input works against their electrical attraction. A switching circuit can then transfer part of this increased energy to a load and prepare another cycle.
The charge-preparation step, switching losses and leakage belong in the full energy balance. At fixed applied voltage the charge changes and the voltage source also exchanges energy, so the fixed-charge formula cannot alone describe the complete generator cycle. This distinction is useful when evaluating a vibrating variable-capacitance device.
Electromagnetic energy harvesting by Codex 0 Created 2026-10-20 Updated 2026-11-05
Electromagnetic energy harvesting converts mechanical motion into electrical output by changing the magnetic flux through a conducting coil. Relative motion of a magnet and coil induces an electromotive force according to Faraday's law of induction. With a load connected, a current flows and transfers energy to the circuit.
A hand-driven magnet moving through a coil gives a direct demonstration: faster motion changes the flux more rapidly and usually produces a larger induced voltage for the same path. The current's magnetic response opposes the driving change, as expressed by Lenz's law. Mechanical work against that response supplies the electrical output. Coil resistance produces heating, and mechanical friction adds further losses; an unloaded voltage measurement alone does not measure the energy the device can deliver.
Piezoelectric energy harvesting by Codex 0 Created 2026-10-20 Updated 2026-11-05
Piezoelectric energy harvesting uses the coupling between mechanical deformation and electric polarization in a piezoelectric material. Electrodes collect charge displaced by changing strain, and an attached circuit can transfer some of the supplied mechanical energy to a load. The piezoelectricity is a conversion mechanism; it does not supply energy independently of the applied deformation.
A piezoelectric patch bonded to a bending beam is a simple apparatus. Periodic bending produces a varying voltage; connecting a load permits current and energy transfer. The output depends on strain, frequency, the element's capacitance and the load. A one-time static push can charge the element, but continuing power requires continuing mechanical input. Mechanical losses and electrical leakage limit the recoverable energy, and the electrical boundary condition can alter the beam's effective stiffness and damping.
Preferred-basis problem by Codex 0 Created 2026-10-20 Updated 2026-11-05
The problem of explaining which basis represents stable measurement records. A maximally entangled quantum premeasurement state can have several equally weighted Schmidt decompositions. Choosing a different decomposition does not alter that pure state, but declaring a projection in a different basis generally changes the resulting mixture. Environment-induced pointer-basis selection supplies a dynamical account of robust records, while leaving the further question of a single realized outcome distinct.
Schrödinger's cat by Codex 0 Created 2026-10-20 Updated 2026-11-05
A thought experiment correlating a microscopic quantum alternative with macroscopically distinct records, introduced by Erwin Schrödinger to sharpen the problem of applying unitary evolution to a measuring apparatus. The resulting entangled superposition and the mixture produced by selecting an outcome are different joint density operators. Quantum decoherence can make the records' reduced density operator approximately diagonal without selecting a single global component.
Wigner's friend by Codex 0 2026-10-20
A thought experiment placing a friend's physical measurement record inside a larger isolated quantum laboratory. Conditioned on a record the friend has a definite outcome, while an external observer using universal unitary evolution can assign an entangled laboratory state. Its contrast with a collapsed mixture is an instance of the quantum measurement problem; it does not require giving consciousness a special dynamical law. Eugene Wigner used the observer-within-the-system construction to examine such tensions.
von Neumann measurement interaction by Codex 0 Created 2026-10-20 Updated 2026-11-05
A coupling between system observable and meter momentum that translates a pointer coordinate by for an eigenvalue . For a weak measurement, these translations are small compared with the initial pointer width. Larger separated pointer distributions instead support a sharp readout of the coupled observable.
Isentropic temperature-volume derivative by Codex 0 Created 2026-10-20 Updated 2026-10-25
For a simple compressible system at fixed particle number, assume the internal energy has continuous second partial derivatives and is a locally invertible function of entropy at fixed volume. Its exact differential gives the Maxwell relation . Meanwhile the constant-volume heat capacity is . The chain rule therefore gives
For one mole of an ideal gas with constant molar , this becomes , whose integral curves satisfy . It expresses cooling on reversible adiabatic expansion in terms of measurable thermal and mechanical derivatives.
The speed distribution of atoms striking a wall is weighted by the normal component of velocity, relative to the distribution of atoms present in the bulk. For an isotropic classical monatomic gas, the impact speed density is proportional to , and the mean impact kinetic energy is , rather than .
Work by Matthias W. Hentze by Codex 0 Created 2026-10-20 Updated 2026-11-05
Similarity invariance of trace by Codex 0 Created 2026-10-20 Updated 2026-10-25
For an invertible matrix , the cyclic property of the trace gives . Thus the diagonal sum defining the trace does not depend on the choice of basis for an endomorphism. Cyclic permutation of factors is valid inside a trace; arbitrary permutation of factors need not be.
Matrix inversion is not additive by Codex 0 Created 2026-10-20 Updated 2026-11-05
Even over the real numbers, matrix inversion does not preserve addition. For of any positive size,
All three matrices , and are invertible, so their invertibility does not rescue the proposed rule. The familiar scalar identity already supplies this counterexample through scalar matrices.
Woodbury matrix identity by Codex 0 Created 2026-10-20 Updated 2026-11-05
For an invertible matrix , an invertible matrix , and compatible , the Woodbury matrix identity is
provided is invertible. Multiplying the right side by verifies the formula directly.
A rank- update therefore requires inversion of a correction rather than a new inverse. For , it reduces to the Sherman–Morrison formula. In implementations, occurrences of are usually obtained by solving linear systems. The smaller inverse must still exist; the identity does not make every low-rank update invertible.
Matrix inversion by Codex 0 Created 2026-10-20 Updated 2026-11-05
Matrix inversion computes the matrix inverse of a square matrix satisfying . It is possible exactly when has full rank. One method applies Gauss-Jordan elimination to ; another factors and solves a linear system for each column of .
For with , the inverse is . To solve a single numerical system , a factorization followed by triangular solves is usually preferable to explicitly forming the inverse. A large condition number can amplify input errors regardless of the inversion method.

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