Magnetic Fields magnetism Questions. How does the Earth make its magnetism? Fun Facts Aboutmagnetism. * The magnetic north and south poles do not stay still. http://purcell.phy.nau.edu/courses/00/spring/sci420/misc/students/felts_wendy/
Extractions: This illustration shows an idealized image of the Earth's dipole magnetic field. The Earth's magnetic field is very similar to a bar or dipole magnet thus the following experiment will help students to understand the concept of the Earth's dipole magnetic field. The Earth's magnetic filed is called the "magnetosphere" and stretches over 37,000 miles into space. The first step in the magnetism experiment is to gather the necessary materials. Materials needed for this experiment are a bar magnet, iron filings, a sheet of transparency paper (for easy clean up) and a clear plastic box lid. You may choose to use other shapes of magnets as well. The next step is to assemble the materials. Place the bar magnet under the clear box lid, place the transparency on top of the lid and pour on the iron filings. You will soon be able to see the filings line up into magnetic field. With the end result, the magnetic field lines are clearly visible, thus showing the magnetic potential of this magnet. How does the Earth make its magnetism?
INTERSCIENTIA: RADICALS AND MAGNETISM Control of chemical Reactions with Magnetic fields - JC Scaiano Departmentof Chemistry, University of Ottawa, Ottawa, Ontario, K1N 6N5. Resumen. http://www.uottawa.ca/publications/interscientia/inter.1/magnetic.html
Extractions: Resumen. Los campos magnéticos pueden influenciar la cinética y productos de reacciones químicas cuando estas involucran la participación de pares de radicales libres. En general estos procesos conducen a un incremento de la vida media y concentración de los radicales. Dada la reconocida participación de radicales libres en procesos biológicos - tales como envejecimiento y cancer - es interesante determinar si los campos magnéticos pueden tener influencia sobre la salud. Magnetic fields can have a dramatic influence on the outcome of certain chemical reactions. In general, these are reactions that involve the intermediacy of free radicals , or molecules that by possessing an odd number of electrons, can be viewed as "molecular magnets". Free radicals are usually short lived (<10 s) and decay either by reactions with other free radicals, or by reacting with molecules, in which case, a new free radical is generated. In the last few years, there has been considerable interest in the biological and health sciences in relation to possible health risks associated with the environmental exposure to magnetic fields related to the production, distribution and utilization of electrical energy. It seems reasonable to assume that any health related consequences must result from biological effects, and that these, in turn, can only result if a magnetic field can exert influence at a molecular level. On the basis of the premise, we have directed our research toward the understanding of simple chemical systems that can be influenced by modest magnetic fields.
Materials, Methods, Microstructure, And Magnetism Materials, Methods, Microstructure, and magnetism. field magnetic moments for theatoms, while the right frame shows the corresponding constraining fields. http://www.nersc.gov/research/annrep98/stocks.html
Extractions: Figure 1. 512-atom base-centered cubic iron system. The left frame shows the self-consistent field magnetic moments for the atoms, while the right frame shows the corresponding constraining fields. Atom positions are denoted by spheres, magnetic moments by arrows, and constraining fields by cones. (Click either image for larger version.) To develop first-principles quantum mechanical methods for addressing materials problems microscopically, especially the relationship between technical magnetic properties and microstructure. Towards this goal are major problems involving microstructure (independent of magnetism), magnetism (independent of microstructure), giant magneto-resistance, and thermal properties. A new constrained local moment (CLM) theory of non-equilibrium states in metallic magnets has been developed that places a recent proposal of our co-workers at Ames Laboratory for first-principles spin dynamics (SD) on firm theoretical foundations. In SD, non-equilibrium "local moments" (for example, in magnets above the Curie temperature, or in the presence of an external field) evolve from one time step to the next according to a classical equation of motion. As originally formulated, the instantaneous magnetization states that are being evolved were not properly defined within density functional theory. The CLM theory properly formulates SD within constrained density functional theory. Local constraining fields are introduced, the purpose of which is to force the local moments to point in directions required at a particular time step of SD. A general algorithm for finding the constraining fields has been developed.
Extractions: GENERATION, MEASURING TECHNIQUE AND APPLICATION OF PULSED FIELDS TO MAGNETISM R.Grössinger Institute of Solid State Physics Vienna University of Technology Vienna , Austria Static fields using a superconducting coil are limited by the critical field The use of larger DC- power supplies allow the generation of static fields up to 20T. In hybrid systems superconducting magnets are combined with resistive magnets generating fields up to Using an energy storage e.g capacitor bank allows the generation of pulsed fields up to Fields beyond 100T can be produced either in a single turn coil or by flux compression The construction of a stable high field magnet suitable for fields beyond is a very difficult task Different concepts of current distributions and reinforcement of high field magnets will be discussed. For measuring the magnetization the most common used method is based on the law of induction Using pick-up systems needs a careful balanced design Generally the signal is integrated the sensitivity is then limited by the 1/f noise Possible solutions to increase the signal to noise ratio for measuring the magnetization will be shown Measuring in transient fields can cause errors due to two different reasons : i) eddy current errors the background of eddy currents in pulsed fields will be discussed Also a method suited to correct for eddy current errors will be shown. ii) magnetic viscosity effects especially systems with high anisotropy and at low temperatures may show such a changed magnetization curve due to viscosity.
Magnetism Indications Examples. magnetism. Most people are familiar with the general propertiesof magnets but are less familiar with the source of magnetism. http://www.ndt-ed.org/EducationResources/CommunityCollege/MagParticle/Physics/Ma
Extractions: Examples Magnetism Magnets are very common items in the workplace and household. Uses of magnets range from holding pictures on the refrigerator to causing torque in electric motors. Most people are familiar with the general properties of magnets but are less familiar with the source of magnetism. The traditional concept of magnetism centers around the magnetic field and what is know as a dipole. The term " magnetic field " simply describes a volume of space where there is a change in energy within that volume. This change in energy can be detected and measured. The location where a magnetic field can be detected exiting or entering a material is called a magnetic pole. Magnetic poles have never been detected in isolation but always occur in pairs and, thus, the name dipole. Therefore, a
Extractions: - Select a Topic - Measurements Electrostatics Electric Fields Electric Flux Electric Potential Capacitance Current and Resistance Electrical Circuits (DC) Magnetism Sources of Magnetic Fields Magnetism in Matter Electromagnetic Induction Electrical Circuits (AC) Maxwell's Equations Electromagnetic Waves Reflection, Refraction, Polarization Optical Instruments: Mirrors and Lenses Interference Diffraction
Magnetic Field Magnetic fields are produced by electric currents, which can be macroscopic currentsin wires, or microscopic currents associated with electrons in atomic http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/magfie.html
Extractions: Magnetic Field Magnetic fields are produced by electric currents , which can be macroscopic currents in wires, or microscopic currents associated with electrons in atomic orbits. The magnetic field B is defined in terms of force on moving charge in the Lorentz force law . The interaction of magnetic field with charge leads to many practical applications. Magnetic field sources are essentially dipolar in nature, having a north and south magnetic pole. Index Magnetic field concepts HyperPhysics ... Electricity and Magnetism R Nave Go Back Lorentz Force Law Both the electric field and magnetic field can be defined from the Lorentz force law: The electric force is straigtforward, being in the direction of the electric field if the charge q is positive, but the direction of the magnetic part of the force is given by the right hand rule. Index