Subject:
All Disciplines Arts & Humanities Biology & Life Sciences Business & Economics Chemistry & Materials Science Computer Science & Mathematics Engineering Environmental & Earth Sciences Medicine & Pharmacology Physical Sciences Public Health & Healthcare Social Sciences
Sort:
Hottest Latest Alphabetical (A-Z) Alphabetical (Z-A)
Type:
All Topic Review Biography
Topic Review
Uniaxial Tensile Test
Tensile testing, also known as tension testing, is a fundamental materials science and engineering test in which a sample is subjected to a controlled tension until failure. Properties that are directly measured via a tensile test are ultimate tensile strength, breaking strength, maximum elongation and reduction in area. From these measurements the following properties can also be determined: Young's modulus, Poisson's ratio, yield strength, and strain-hardening characteristics. Uniaxial tensile testing is the most commonly used for obtaining the mechanical characteristics of isotropic materials. Some materials use biaxial tensile testing. The main difference between these testing machines being how load is applied on the materials.
  • 4.0K
  • 07 Nov 2022
Topic Review
Unified Atomic Mass Unit
The unified atomic mass unit or dalton (symbol: u, or Da) is a standard unit of mass that quantifies mass on an atomic or molecular scale (atomic mass). One unified atomic mass unit is approximately the mass of one nucleon (either a single proton or neutron) and is numerically equivalent to 1 g/mol. It is defined as one twelfth of the mass of an unbound neutral atom of carbon-12 in its nuclear and electronic ground state and at rest, and has a value of 1.660539040(20)×10−27 kg, or approximately 1.66 yoctograms. The CIPM has categorised it as a non-SI unit accepted for use with the SI, and whose value in SI units must be obtained experimentally. The amu without the "unified" prefix is technically an obsolete unit based on oxygen, which was replaced in 1961. However, many sources still use the term amu but now define it in the same way as u (i.e., based on carbon-12). In this sense, most uses of the terms atomic mass units and amu, today, actually refer to unified atomic mass unit. For standardization, a specific atomic nucleus (carbon-12 vs. oxygen-16) had to be chosen because the average mass of a nucleon depends on the count of the nucleons in the atomic nucleus due to mass defect. This is also why the mass of a proton or neutron by itself is more than (and not equal to) 1 u. The atomic mass unit is not the unit of mass in the atomic units system, which is rather the electron rest mass (me).
  • 8.4K
  • 21 Oct 2022
Topic Review
Universe & Anharmonic Oscillator & Singularity Avoidance Higgs
The functioning of our universe and atomic is based on the oscillation of the particle itself and asymmetrically between matter and antimatter. This mechanism is a classical an-harmonic oscillator and uses a linear oscillation of the particle, where the energy can be represented by the graph of a potential well. In this potential well the alternation of energies ocurs between the kinetic energy and potential energy. This an-harmonic oscillation of the particle thus occurs through a gravitational oscillator (see "hole through the Earth simple harmonic motion"), followed by a singularity avoidance. Indeed the important kinetics of the particle leads to a singularity avoidance to pass over the supermassive black hole to plot the Higgs field/potential. The alternation of the particle at very high frequency generates by the principle of mass-energy equivalence in vacuum (E=mc²) a mass flux expressed by the quantum fluctuation determined by a scalar energy density. This scalar density represents for example the dark matter and the residues of the latter in the quantum vacuum. However a vectorial interpretation of the particle is possible as soon as its oscillation through the oscillator is really minimized before becoming a mass-energy equivalence flux. That represent the elements related to Einstein's Stress Energy Tensor. Here is the one of interpretation of quantum mechanics in relation to relativistic physics. 
  • 2.8K
  • 23 Aug 2022
Topic Review
Unmanned Systems
An Unmanned System (US) or Vehicle (UV) can be defined as an “electro-mechanical system, with no human operator aboard, that is able to exert its power to perform designed missions”
  • 9.0K
  • 17 Mar 2021
Topic Review
Ursa Major
Ursa Major, often referred to as the Great Bear, is one of the most recognizable and prominent constellations in the northern celestial hemisphere. Its distinctive shape, resembling a large bear with a long tail, has captivated human imagination for millennia. At the heart of Ursa Major lies the Big Dipper, a prominent asterism formed by seven bright stars that serve as a navigational guide and cultural icon across cultures and civilizations.
  • 435
  • 15 Mar 2024
Topic Review
Ursa Major Moving Group
The Ursa Major Moving Group, also known as Collinder 285 and the Ursa Major association, is the closest stellar moving group – a set of stars with common velocities in space and thought to have a common origin in space and time. In the case of the Ursa Major group, all the stars formed about 300 million years ago. Its core is located roughly 80 light years away and part of the Local Bubble. It is rich in bright stars including most of the stars of the Big Dipper.
  • 553
  • 14 Oct 2022
Topic Review
Ursa Minor
Ursa Minor, Latin for "Lesser Bear," is a constellation in the northern celestial hemisphere. It is best known for containing the North Star, Polaris, which marks the position of the north celestial pole and aids in navigation. Despite its small size and dim stars, Ursa Minor holds significant cultural and navigational importance throughout human history.
  • 327
  • 15 Mar 2024
Biography
Uschi Steigenberger
Ursula "Uschi" Steigenberger (25 April 1951 — 12 December 2018) OBE FInstP was a German condensed matter physicist and director of the ISIS neutron source. She was one of the founders of the Institute of Physics Juno Award. Steigenberger was born in Augsburg. She studied physics at the University of Würzburg, where she remained for her graduate studies. She earned a PhD in condensed matter
  • 440
  • 01 Dec 2022
Topic Review
UV-Vis Absorption Spectroelectrochemistry
Ultraviolet-visible (UV-Vis) absorption spectroelectrochemistry (SEC) is a multiresponse technique that analyzes the evolution of the absorption spectra in UV-Vis regions during an electrode process. This technique provides information from an electrochemical and spectroscopic point of view. In this way, it enables a better perception about the chemical system of interest. On one hand, molecular information related to the electronic levels of the molecules is obtained from the evolution of the spectra. On the other hand, kinetic and thermodynamic information of the processes is obtained from the electrochemical signal. UV-Vis absorption SEC allows qualitative analysis, through the characterization of the different present compounds, and quantitative analysis, by determining the concentration of the analytes of interest. Furthermore, it helps to determine different electrochemical parameters such as absorptivity coefficients, standard potentials, diffusion coefficients, electronic transfer rate constants, etc. Throughout history, reversible processes have been studied with colored reagents or electrolysis products. Nowadays, it is possible to study all kinds of electrochemical processes in the entire UV-Vis spectral range, even in the near infrared (NIR).
  • 415
  • 31 Oct 2022
Topic Review
V-HOE Based Solar Concentrators
The fundamental advantages of volume holographic optical elements are very appealing for lightweight and cheap solar concentrators applications and can become a valuable asset that can be integrated into solar panels. 
  • 792
  • 10 Jun 2021
  • Page
  • of
  • 131
Featured Entry Collections
>>

Featured Books

>>
Encyclopedia of Social Sciences
Encyclopedia of COVID-19
Encyclopedia of Fungi
Encyclopedia of Digital Society, Industry 5.0 and Smart City
Video Production Service
Feedback