Poinsot's ellipsoid is a geometric representation used in the study of rigid bodies in classical mechanics. It specifically describes the distribution of mass and the inertial properties of a rigid body. The concept is related to the inertia tensor of the body, which characterizes how the mass is distributed relative to its rotational axes. Poinsot's ellipsoid represents the relationships between the principal moments of inertia and the axes of rotation.
An oblique shock is a type of shock wave that occurs in supersonic flows when the flow encounters a ramp, wedge, or other surfaces that create a change in direction. Unlike normal shocks, which are perpendicular to the flow direction, oblique shocks are inclined at an angle relative to the flow direction.
The term "Petrovsky lacuna" refers to a specific problem in the field of functional analysis, particularly in the study of partial differential equations and the theory of distributions. It is associated with the work of the mathematician V. I. Petrovsky, who investigated the properties of certain classes of solutions to partial differential equations, especially those relating to the existence and behavior of weak solutions.
A vapor cone, also known as shock collar or vapor cloud, is a phenomenon that occurs when an aircraft, typically traveling at supersonic speeds (faster than the speed of sound), displaces air in such a way that moisture in the air condenses, creating a visible cloud. This effect is primarily seen around the aircraft's wings and fuselage due to the rapid changes in pressure and temperature as the aircraft breaks the sound barrier.
In anatomy, a "chiasm" refers to a crossing or intersection of nerve fibers, most commonly associated with the optic chiasm. The optic chiasm is a critical structure in the brain where the optic nerves from the eyes partially cross over.
Phosphogypsum is a byproduct generated during the production of phosphoric acid from phosphate rock. The process typically involves the use of sulfuric acid to dissolve the phosphate rock, resulting in phosphoric acid and phosphogypsum as a waste material. The chemical composition of phosphogypsum primarily includes gypsum (calcium sulfate dihydrate), but it often contains varying amounts of impurities such as trace metals, fluoride, and radium, which can make it a concern for environmental and health safety.
A ligament is a type of connective tissue in the body that connects bones to other bones at joints. It is composed primarily of collagen fibers, which provide strength and stability while allowing for some flexibility. Ligaments play a crucial role in supporting and stabilizing joints, preventing excessive movements that could lead to injury. They are essential for maintaining the integrity of the skeletal system during activities that involve movement, bending, and weight-bearing.
Tenotomy is a surgical procedure that involves the cut or division of a tendon. This procedure is typically performed to relieve tension in the tendon, to correct deformities, or to improve the function of a joint. Tenotomies can be used in various medical contexts, particularly in orthopedic and sports medicine, to address conditions like tendonitis, contractures, or to facilitate a more effective range of motion in joints affected by tight or abnormal tendons.
The Beeswax Wreck is a notable shipwreck located off the coast of Cape Hatteras in North Carolina, USA. It is believed to be the remains of a 19th-century wooden sailing vessel that was transporting beeswax, a valuable commodity at the time, hence its name. The wreck is of interest to marine archaeologists and historians due to its potential to provide insights into maritime trade and shipping practices during that period.
Chinese wax, often referred to as "Chinese wax scale," is a natural product derived from the secretions of certain scale insects, specifically those belonging to the genus **Ceroplastes**. The wax is produced by these insects as a protective covering for themselves, and it appears as a white or yellowish substance.
Jojoba oil is a liquid extracted from the seeds of the jojoba plant (Simmondsia chinensis), which is native to southern Arizona, California, and northwestern Mexico. Unlike most plant oils, jojoba oil is actually a wax ester, closely resembling the natural oils produced by human skin, making it a popular ingredient in cosmetics and skincare products.
Mustache wax is a grooming product specifically designed to style and shape mustaches. It typically comes in a small tin or jar and is made from a blend of natural waxes, such as beeswax and lanolin, along with oils and sometimes fragrances. The primary purpose of mustache wax is to provide hold, allowing the user to mold the mustache into various styles—like curls, twists, or other shapes—while helping to tame unruly hairs.
Ouricury wax is a natural wax derived from the leaves and fruits of the Ouricury palm tree (Astrocaryum aculeatum), which is native to Brazil and other parts of South America. This wax is known for its unique properties, including its emollient, thickening, and stabilizing capabilities.
Renaissance Wax is a micro-crystalline wax used primarily for protecting and preserving a variety of surfaces, including metal, wood, leather, and stone. It is known for its ability to provide a thin, protective layer that helps prevent tarnishing, corrosion, and other forms of deterioration, while also enhancing the appearance of the surface it's applied to.
"Wax fire" often refers to a specific type of fire that can occur in environments where flammable wax is present, such as candle-making or candle-burning scenarios. It can also sometimes refer to incidents involving wax or waxy substances catching fire, primarily due to heat sources or improper handling. In a more general sense, wax is a combustible material, and if it reaches its flash point, it can ignite.
The "List of Nuclides" refers to a comprehensive catalog of all known isotopes (nuclides) of the chemical elements, including both stable and radioactive forms. Each nuclide is characterized by its atomic number (the number of protons), mass number (the total number of protons and neutrons), and sometimes its specific energy states and half-lives if it is radioactive.
A segmented, narrow table of nuclides is a graphical representation that organizes nuclides (different isotopes of elements) according to their atomic number (protons) and mass number (protons plus neutrons). The table is often segmented to reflect various properties of the nuclides, such as stability, mode of decay, or type of nuclear interactions.
Walter Seelmann-Eggebert was a German artist, primarily known for his work as an illustrator and writer. He is notable for his contributions to children's literature and other illustrative works. His drawings often featured whimsical and imaginative themes, and he is remembered for his distinctive style. Seelmann-Eggebert's legacy includes a variety of illustrated books and artworks that continue to be appreciated for their charm and creativity.
Sandra Lahire was a British filmmaker and artist known for her experimental films and video works that often explore themes of feminism, memory, and the complexities of identity. Her work frequently incorporated personal narratives, blending autobiographical elements with broader social and political issues. Lahire's films were characterized by their innovative use of visual imagery and sound, often challenging traditional narrative structures.
The Formerly Utilized Sites Remedial Action Program (FUSRAP) is a program established by the U.S. government, specifically the Department of Energy (DOE), to address and remediate sites where radioactive contamination resulted from activities conducted by the Atomic Energy Commission and its successor agencies. The program was initiated in 1974 and aims to identify, assess, and clean up sites where radioactive or hazardous materials were left from former government operations, including the processing and disposal of nuclear materials.

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