background preloader

Small bang theory

Facebook Twitter

Annealing (metallurgy) In annealing, atoms migrate in the crystal lattice and the number of dislocations decreases, leading to the change in ductility and hardness.

Annealing (metallurgy)

In the cases of copper, steel, silver, and brass, this process is performed by heating the material (generally until glowing) for a while and then slowly letting it cool to room temperature in still air. Ferromagnetism. Not to be confused with Ferrimagnetism; for an overview see Magnetism.


A magnet made of alnico, an iron alloy, with its keeper. Ferromagnetism is the theory which explains how materials become magnets. Ferromagnetism is the basic mechanism by which certain materials (such as iron) form permanent magnets, or are attracted to magnets. In physics, several different types of magnetism are distinguished. Ferromagnetism (including ferrimagnetism)[1] is the strongest type: it is the only one that typically creates forces strong enough to be felt, and is responsible for the common phenomena of magnetism in magnets encountered in everyday life.

Permanent magnets (materials that can be magnetized by an external magnetic field and remain magnetized after the external field is removed) are either ferromagnetic or ferrimagnetic, as are other materials that are noticeably attracted to them. History and distinction from ferrimagnetism[edit] Ferromagnetic materials[edit] Actinide ferromagnets[edit] Preisach model of hysteresis. Hysteresis. Such loops may occur purely because of a dynamic lag between input and output.


This effect disappears as the input changes more slowly. This effect meets the description of hysteresis given above, but is often referred to as rate-dependent hysteresis to distinguish it from hysteresis with a more durable memory effect. Etymology and history[edit] The term "hysteresis" is derived from ὑστέρησις, an ancient Greek word meaning "deficiency" or "lagging behind". Electromagnetic spectrum. The electromagnetic spectrum is the range of all possible frequencies of electromagnetic radiation.[4] The "electromagnetic spectrum" of an object has a different meaning, and is instead the characteristic distribution of electromagnetic radiation emitted or absorbed by that particular object.

Electromagnetic spectrum

Most parts of the electromagnetic spectrum are used in science for spectroscopic and other probing interactions, as ways to study and characterize matter.[6] In addition, radiation from various parts of the spectrum has found many other uses for communications and manufacturing (see electromagnetic radiation for more applications). History of electromagnetic spectrum discovery[edit] The first discovery of electromagnetic radiation other than visible light came in 1800, when William Herschel discovered infrared radiation.[7] He was studying the temperature of different colors by moving a thermometer through light split by a prism.

He noticed that the highest temperature was beyond red. - Simple Harmonic (and non-harmonic) Motion. [S | t | ★★★★] keywords: simple harmonic motion, periodic motion, quantum revival, aliasing What it shows: Fifteen uncoupled simple pendulums of monotonically increasing lengths dance together to produce visual traveling waves, standing waves, beating, and random motion.

- Simple Harmonic (and non-harmonic) Motion

The Proton Radius Prediction and Gravitational Control. Bending the light - physics experiment. Resonant Transparency and Non-Trivial Non-Radiating Excitations in Toroidal Metamaterials : Scientific Reports. Nonradiating anapole modes in dielectric nanoparticles : Nature Communications. New theory leads to 'radiationless revolution': Physicists have found a radical new way confine electromagnetic energy without it leaking away, akin to throwing a pebble into a pond with no splash. Physicists have found a radical new way confine electromagnetic energy without it leaking away, akin to throwing a pebble into a pond with no splash.

New theory leads to 'radiationless revolution': Physicists have found a radical new way confine electromagnetic energy without it leaking away, akin to throwing a pebble into a pond with no splash

The theory could have broad ranging applications from explaining dark matter to combating energy losses in future technologies. However, it appears to contradict a fundamental tenet of electrodynamics, that accelerated charges create electromagnetic radiation, said lead researcher Dr Andrey Miroshnichenko from The Australian National University (ANU). "This problem has puzzled many people. It took us a year to get this concept clear in our heads," said Dr Miroshnichenko, from the ANU Research School of Physics and Engineering. The fundamental new theory could be used in quantum computers, lead to new laser technology and may even hold the key to understanding how matter itself hangs together. Keeping warm: Coordinated movements in a penguin huddle. To survive temperatures below -50 ° C and gale-force winds above 180 km/h during the Antarctic winter, Emperor penguins form tightly packed huddles and, as has recently been discovered -- the penguins actually coordinate their movements to give all members of the huddle a chance to warm up.

Keeping warm: Coordinated movements in a penguin huddle

Physicist Daniel P. Zitterbart from the University of Erlangen-Nuremberg, Germany, recently spent a winter at Dronning Maud Land in the Antarctic, making high-resolution video recordings of an Emperor penguin colony. Together with biophysicist Ben Fabry from Erlangen University, physiologist James P. Looking At Tears Under A Microscope Reveals A Shocking Fact.

Share on Facebook One day Rose-Lynn Fisher wondered if her tears of grief would look different compared to her tears of joy, so she began to explore them up close under a microscope.

Looking At Tears Under A Microscope Reveals A Shocking Fact.

Le Châtelier's Principle. Le Châtelier's principle states that if a dynamic equilibrium is disturbed by changing the conditions, the position of equilibrium shifts to counteract the change to reestablish an equilibrium.

Le Châtelier's Principle

If a chemical reaction is at equilibrium and experiences a change in pressure, temperature, or concentration of products or reactants, the equilibrium shifts in the opposite direction to offset the change. This page covers changes to the position of equilibrium due to such changes and discusses briefly why catalysts have no effect on the equilibrium position. Introduction. The Effect of Changing Conditions. Creep (deformation) The rate of deformation is a function of the material properties, exposure time, exposure temperature and the applied structural load.

Creep (deformation)

Depending on the magnitude of the applied stress and its duration, the deformation may become so large that a component can no longer perform its function — for example creep of a turbine blade will cause the blade to contact the casing, resulting in the failure of the blade. Creep is usually of concern to engineers and metallurgists when evaluating components that operate under high stresses or high temperatures. Creep is a deformation mechanism that may or may not constitute a failure mode. For example, moderate creep in concrete is sometimes welcomed because it relieves tensile stresses that might otherwise lead to cracking. Necking (engineering)

A polyethylene sample with a stable neck. Necking results from an instability during tensile deformation when a material's cross-sectional area decreases by a greater proportion than the material strain hardens. Considère published the basic criterion for necking in 1885.[3] Three concepts provide the framework for understanding neck formation. The latter two items determine the stability while the first item determines the neck's location.

Graphical construction indicating criteria for neck formation and neck stabilization. Poisson's ratio. Viscoelasticity. Background[edit]