The Ultrasonic Pulse Velocity (UPV) test is a non-destructive testing method used to assess the quality and structural integrity of concrete and other solid materials. The primary purpose of this test is to measure the speed at which an ultrasonic pulse travels through a material, which can provide important information about its properties, such as density, elasticity, and the presence of voids or cracks.
A Yao graph is a specific type of geometric graph used primarily in the field of computational geometry and computer science, particularly in the context of network design and algorithms. It was introduced by Andrew Yao in the 1980s. The Yao graph is constructed based on a set of points in a Euclidean space, usually in two or three dimensions.
Asymptotic dimension is a concept from geometric topology and metric geometry that provides a way to measure the "size" or "dimension" of a metric space in a manner that is sensitive to the space's large-scale structure. It was introduced by the mathematicians J. M. G. B. Connes and more extensively developed by others in the context of spaces that arise in analysis, algebra, and topology.
Greedy coloring is a graph coloring algorithm used to assign colors to the vertices of a graph such that no two adjacent vertices share the same color. The goal of graph coloring is to minimize the number of colors used, and greedy coloring serves as a heuristic method for this purpose. ### Basic Procedure The greedy coloring algorithm typically follows these steps: 1. **Order the Vertices**: Start by ordering the vertices of the graph.
The Grushko theorem is a result in the field of group theory, particularly concerning free groups and their subgroups. It provides a criterion to establish whether a given group is free and helps characterize the structure of free groups.
In mathematics, "outer space" typically refers to a certain type of geometric space associated with free groups and their actions. The most common reference is to "Outer space" denoted as \( \mathcal{O}(F_n) \), which is the space of marked metric graphs that correspond to the free group \( F_n \) of rank \( n \).
Stallings' theorem concerns the structure of finitely generated groups in relation to their ends. In topology, the "ends" of a space can intuitively be understood as the number of "directions" in which the space can be infinitely extended. For groups, ends are related to how a group's Cayley graph behaves at infinity.
The Blaschke–Lebesgue theorem is a result in the field of measure theory and functional analysis, particularly concerning the properties of certain types of functions in the context of completeness and limit points. The theorem specifically addresses the behavior of sequences of orthogonal functions in a Hilbert space.
The sphere-cylinder intersection refers to the geometric analysis of the points where a sphere intersects with a cylindrical surface. This can be a complex topic in mathematics and computational geometry, often leading to equations and visualizations that help understand the relationship between the two objects. ### Definitions: 1. **Sphere**: A three-dimensional shape where all points on the surface are equidistant from a center point.
Position sensors are devices used to detect and measure the position or displacement of an object. They are crucial in various applications, such as robotics, automation, automotive systems, and industrial machinery, to monitor the movement and positioning of components. Position sensors convert physical position changes into signals that can be interpreted by electronic control systems. There are several types of position sensors, including: 1. **Linear Position Sensors**: Measure the position of an object along a straight line.
Woodworking measuring instruments are tools used by woodworkers to measure, mark, and ensure the accuracy and precision of their projects. These instruments are essential for achieving the desired dimensions and fit of wooden pieces, whether for furniture making, cabinetry, or other woodworking projects. Here are some common woodworking measuring instruments: 1. **Tape Measure**: A flexible measuring tool that allows for measuring lengths and distances over various surfaces. It usually includes both metric and imperial measurements.
Plücker's conoid is a geometric surface that arises in the study of differential geometry and mathematical surfaces. It is named after the German mathematician Julius Plücker, who explored various geometric properties in the 19th century. The Plücker's conoid is defined in the context of a curve in three-dimensional space. Specifically, it can be generated by taking a curve in the plane and rotating it around a line (called the axis of rotation) that lies in the same plane.
As of my last update in October 2023, "Squround" isn't a widely recognized term or concept in popular culture, technology, or business. It could potentially refer to a specific product, service, game, or a term relevant to a niche area not broadly covered in mainstream sources.
The term "whorl" can refer to a few different concepts, depending on the context: 1. **Biology**: In botanical terms, a whorl refers to a circular arrangement of leaves, flowers, or other plant organs around a single stem at the same level. For example, if you see multiple leaves growing in a circle around a stem, that is called a whorl.
Brewster's angle, also known as the polarization angle, is the angle of incidence at which light with a particular polarization is perfectly transmitted through a transparent dielectric surface, with no reflection. At this angle, the reflected light is completely polarized perpendicular to the plane of incidence. Mathematically, Brewster's angle (θ_B) can be determined using the refractive indices of the two media involved.
In optics, cardinal points refer to specific points in an optical system, such as a lens or a mirror, that are important for describing the behavior of light as it passes through the system. These points include: 1. **Focal Points**: - **Focal Point (F)**: The point where parallel rays of light converge after passing through a converging lens (or mirror).
Defocus aberration is an optical distortion that occurs when light rays entering a lens do not converge at the intended focal point. This aberration typically results in images that appear blurred. It is primarily caused by the positioning of the lens relative to the image sensor or film plane, which can be affected by factors such as: 1. **Incorrect Focus**: If the subject is not perfectly in focus, the light rays will fail to converge at the correct point, leading to blurriness.
"Shooting and bouncing rays" is a technique commonly used in computer graphics, particularly in the context of rendering techniques such as ray tracing. This method is instrumental in simulating realistic illumination and reflections in a scene. Here's a breakdown of the concepts: ### Shooting Rays "Shooting rays" refers to the process of casting rays from a viewpoint or camera into a scene.
A magnetic survey in archaeology is a non-invasive geophysical method used to detect and map archaeological features buried beneath the ground by measuring variations in the Earth's magnetic field. This technique is particularly effective for identifying structures such as walls, hearths, ditches, and other features that have been altered or disturbed by human activity. ### How it Works: 1. **Magnetic Field Measurement**: Archaeologists use magnetometers to measure the magnetic field intensity at various points on the ground surface.
In optics, a "ray" is an abstract concept used to represent the path along which light travels. It is typically depicted as a straight line with an arrow indicating the direction of light propagation. Rays are fundamental in understanding how light interacts with various optical elements, such as lenses, mirrors, and prisms.

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 2.
    You can publish local OurBigBook lightweight markup files to either https://OurBigBook.com or as a static website
    .
    Figure 3.
    Visual Studio Code extension installation
    .
    Figure 4.
    Visual Studio Code extension tree navigation
    .
    Figure 5.
    Web editor
    . 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.
    Video 4.
    OurBigBook Visual Studio Code extension editing and navigation demo
    . Source.
  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