Magnetohydrodynamics is a model of electrically conducting fluids that treats all interpenetrating particle species together as a single continuous medium. It is primarily concerned with the low-frequency, large-scale, magnetic behavior in plasmas and liquid metals and has applications in multiple fields including geophysics, astrophysics, and engineering.
A nuclear electromagnetic pulse is a burst of electromagnetic radiation created by a nuclear explosion. The resulting rapidly varying electric and magnetic fields may couple with electrical and electronic systems to produce damaging current and voltage surges. The specific characteristics of a particular nuclear EMP event vary according to a number of factors, the most important of which is the altitude of the detonation.
A railgun or rail gun is a linear motor device, typically designed as a weapon, that uses electromagnetic force to launch high-velocity projectiles. The projectile normally does not contain explosives, instead relying on the projectile's high kinetic energy to inflict damage. The railgun uses a pair of parallel conductors (rails), along which a sliding armature is accelerated by the electromagnetic effects of a current that flows down one rail, into the armature and then back along the other rail. It is based on principles similar to those of the homopolar motor.
Flow measurement is the quantification of bulk fluid movement. Flow can be measured using devices called flowmeters in various ways. The common types of flowmeters with industrial applications are listed below:
LS-DYNA is an advanced general-purpose multiphysics simulation software package developed by the former Livermore Software Technology Corporation (LSTC), which was acquired by Ansys in 2019. While the package continues to contain more and more possibilities for the calculation of many complex, real world problems, its origins and core-competency lie in highly nonlinear transient dynamic finite element analysis (FEA) using explicit time integration. LS-DYNA is used by the automobile, aerospace, construction and civil engineering, military, manufacturing, and bioengineering industries.
Electron-beam welding (EBW) is a fusion welding process in which a beam of high-velocity electrons is applied to two materials to be joined. The workpieces melt and flow together as the kinetic energy of the electrons is transformed into heat upon impact. EBW is often performed under vacuum conditions to prevent dissipation of the electron beam.
Particle image velocimetry (PIV) is an optical method of flow visualization used in education and research. It is used to obtain instantaneous velocity measurements and related properties in fluids. The fluid is seeded with tracer particles which, for sufficiently small particles, are assumed to faithfully follow the flow dynamics. The fluid with entrained particles is illuminated so that particles are visible. The motion of the seeding particles is used to calculate speed and direction of the flow being studied.
Electromagnetic forming is a type of high-velocity, cold forming process for electrically conductive metals, most commonly copper and aluminium. The workpiece is reshaped by high-intensity pulsed magnetic fields that induce a current in the workpiece and a corresponding repulsive magnetic field, rapidly repelling portions of the workpiece. The workpiece can be reshaped without any contact from a tool, although in some instances the piece may be pressed against a die or former. The technique is sometimes called high-velocity forming or electromagnetic pulse technology.
Friction stir welding (FSW) is a solid-state joining process that uses a non-consumable tool to join two facing workpieces without melting the workpiece material. Heat is generated by friction between the rotating tool and the workpiece material, which leads to a softened region near the FSW tool. While the tool is traversed along the joint line, it mechanically intermixes the two pieces of metal, and forges the hot and softened metal by the mechanical pressure, which is applied by the tool, much like joining clay, or dough. It is primarily used on wrought or extruded aluminium and particularly for structures which need very high weld strength. FSW is capable of joining aluminium alloys, copper alloys, titanium alloys, mild steel, stainless steel and magnesium alloys. More recently, it was successfully used in welding of polymers. In addition, joining of dissimilar metals, such as aluminium to magnesium alloys, has been recently achieved by FSW. Application of FSW can be found in modern shipbuilding, trains, and aerospace applications.
Pulsed power is the science and technology of accumulating energy over a relatively long period of time and releasing it instantly, thus increasing the instantaneous power. They can be used in some applications such as food processing, water treatment, weapon, and medical applications.
A slapper detonator, also called exploding foil initiator (EFI), is a detonator developed by Lawrence Livermore National Laboratory, US Patent No. 4,788,913. It is an improvement over the earlier exploding-bridgewire detonator. Instead of directly coupling the shock wave from the exploding wire, the expanding plasma from an explosion of a metal foil drives another thin plastic or metal foil called a "flyer" or a "slapper" across a gap, and its high-velocity impact on an explosive then delivers the energy and shock needed to initiate a detonation. Normally all the slapper's kinetic energy is supplied by the heating of the plasma by the current passing through it, though constructions with a "back strap" to further drive the plasma forward by magnetic field also exist. This assembly is quite efficient; up to 30% of the electrical energy can be converted to the slapper's kinetic energy. The device's name is derived from the English word "slap".
Plasma modeling refers to solving equations of motion that describe the state of a plasma. It is generally coupled with Maxwell's equations for electromagnetic fields or Poisson's equation for electrostatic fields. There are several main types of plasma models: single particle, kinetic, fluid, hybrid kinetic/fluid, gyrokinetic and as system of many particles.
Electron-beam machining (EBM) is a process where high-velocity electrons concentrated into a narrow beam that are directed towards the work piece, creating heat and vaporizing the material. EBM can be used for very precise cutting or boring of a wide variety of metals. Surface finish is better and kerf width is narrower than those for other thermal cutting processes.
Plasma is one of four fundamental states of matter characterized by the presence of a significant portion of charged particles in any combination of ions or electrons. It is the most abundant form of ordinary matter in the universe, mostly in stars, but also dominating the rarefied intracluster medium and intergalactic medium. Plasma can be artificially generated, for example, by heating a neutral gas or subjecting it to a strong electromagnetic field.
William F. Brown was an American welding engineer, professional engineer and magnetic pulse welding expert.
Lorentz force velocimetry (LFV) is a noncontact electromagnetic flow measurement technique. LFV is particularly suited for the measurement of velocities in liquid metals like steel or aluminium and is currently under development for metallurgical applications. The measurement of flow velocities in hot and aggressive liquids such as liquid aluminium and molten glass constitutes one of the grand challenges of industrial fluid mechanics. Apart from liquids, LFV can also be used to measure the velocity of solid materials as well as for detection of micro-defects in their structures.
An electromagnetic pulse (EMP), also referred to as a transient electromagnetic disturbance (TED), is a brief burst of electromagnetic energy. The origin of an EMP can be natural or artificial, and can occur as an electromagnetic field, as an electric field, as a magnetic field, or as a conducted electric current. The electromagnetic interference caused by an EMP can disrupt communications and damage electronic equipment. An EMP such as a lightning strike can physically damage objects such as buildings and aircraft. The management of EMP effects is a branch of electromagnetic compatibility (EMC) engineering.
Magnetic resonance velocimetry (MRV) is an experimental method to obtain velocity fields in fluid mechanics. MRV is based on the phenomenon of nuclear magnetic resonance and adapts a medical magnetic resonance imaging system for the analysis of technical flows. The velocities are usually obtained by phase contrast magnetic resonance imaging techniques. This means velocities are calculated from phase differences in the image data that has been produced using special gradient techniques. MRV can be applied using common medical MRI scanners. The term magnetic resonance velocimetry became current due to the increasing use of MR technology for the measurement of technical flows in engineering.
The hemodynamics of the aorta is an ongoing field of research in which the goal is to identify what flow patterns and subsequent forces occur within the thoracic aorta. These patterns and forces are used to identify the presence and severity of cardiovascular diseases such as aortic aneurysm and atherosclerosis. Some of the methods used to study the hemodynamics of aortic flow are patient scans, computational fluid dynamics models, and particle tracking velocimetry (PTV). The information gathered through these studies can be used for surgery planning and the development of implants. Greater understanding of this topic reduces mortality rates associated with cardiovascular disease.
