Inductrack III is specifically designed for very heavy cargo loads moved at slow speeds. Inductrack trains could levitate higher with greater stability. As long as it's moving a few miles per hour, an Inductrack train will levitate nearly an inch 2. A greater gap above the track means that the train would not require complex sensing systems to maintain stability.
Permanent magnets had not been used before because scientists thought that they would not create enough levitating force. The Inductrack design bypasses this problem by arranging the magnets in a Halbach array. The magnets are configured so that the intensity of the magnetic field concentrates above the array instead of below it. They are made from a newer material comprising a neodymium-iron-boron alloy, which generates a higher magnetic field.
The Inductrack II design incorporates two Halbach arrays to generate a stronger magnetic field at lower speeds. Notably, the passive magnetic levitation concept is a core feature of proposed hyperloop transportation systems, which is essentially an Inductrack-style train that blasts through a sealed tube that encases the entire track. It's possible that hyperloops may become the approach of choice, in part because they dodge the issue of air resistance in the way the regular maglevs cannot, and thus, should be able to achieve supersonic speeds.
Some say that a hyperloop might cost even less than a traditional high-speed rail line. But whereas maglev trains are already a proven technology with years of operational history, no one has yet built a commercial hyperloop anywhere in the world [source: Davies ]. While maglev transportation was first proposed more than a century ago, the first commercial maglev train didn't become a reality until , when a low-speed maglev shuttle became operational between the United Kingdom's Birmingham International railway station and an airport terminal of Birmingham International Airport.
Since then, various maglev projects have started, stalled, or been outright abandoned. However, there are currently six commercial maglev lines, and they're all located in South Korea, Japan and China. The fact that maglev systems are fast, smooth and efficient doesn't change one crippling fact — these systems are incredibly expensive to build. Some critics lambast maglev projects as costs perhaps five times as much as traditional rail lines.
But proponents point out that the cost of operating these trains is, in some cases, up to 70 percent less than with old-school train technology [sources: Hall , Hidekazu and Nobuo ]. It doesn't help that some high-profile projects have flopped.
The administration at Old Dominion University in Virginia had hoped to have a super shuttle zipping students back and forth across campus starting back in the fall semester of , but the train did a few test runs and never really approached the 40 mph 64 kph speeds it promised. But other projects persist. One ambitious group wants to build a mile kilometer stretch from Washington D. The concept's exorbitant price tag might be laughable just about anywhere else in the world, but this region's soul-crushing gridlock and limited space means city planners and engineers need an innovative solution, and a super-fast maglev system might be the best option.
A key selling point — an expansion to this project could connect to Washington to New York city and cut travel times to just 60 minutes, a speedy commute that could transform commerce and travel in the Northeast [sources: Lazo , Northeast Maglev ].
In Asia, though, the maglev boom is essentially already underway. Japan is working feverishly on a Tokyo-to-Osaka route that may open by When it's complete, the train will slash the nearly three hour trip to just 67 minutes [source: Reuters ].
China is seriously considering dozens of potential maglev routes, all of them in congested areas that require high-capacity mass transportation.
These won't be high-speed trains. Instead, they'll move lots of people over shorter distances at lower speeds. Nevertheless, China manufactures all of its own maglev technologies and is about to unveil a third-generation commercial maglev line with a top speed of around mph kph and — unlike previous versions — is completely driverless, relying instead on computer sensors for acceleration and braking The country already has some maglev trains in operation but they need a driver.
It's impossible to know exactly how maglevs will figure into the future of human transportation. Advances in self-driving cars and air travel may complicate the deployment of maglev lines. If the hyperloop industry manages to generate momentum, it could disrupt all sorts of transportation systems.
And some engineers suspect that even flying cars, though incredibly pricey, might trump rail systems in the future because they don't need massive infrastructure projects to get off the ground. Perhaps in just a decade or two, nations around the world will have come to a verdict on maglev trains. Maybe they'll become a linchpin of high-speed travel, or simply pet projects that serve just fragments of certain populations in crowded urban area. Or perhaps they'll simply fade into history, a nearly magical form of levitation technology that just never really took off.
Sign up for our Newsletter! Mobile Newsletter banner close. Mobile Newsletter chat close. Mobile Newsletter chat dots. Mobile Newsletter chat avatar. Mobile Newsletter chat subscribe. This method has the potential to be faster, quieter and smoother than wheeled mass transit systems and the power needed for levitation is usually not a particularly large percentage of the overall consumption; most of it being used to overcome air drag.
Magnetic levitation aka. However, maglev technology overcomes this through a number of means. These include, but are not limited to, mechanical constraint or pseudo-levitation , diamagnetism levitation, superconductors, rotational stabilization, servomechanisms, induced currents and strong focusing. Pseudo-levitation relies on two magnets that are mechanically arranged to repel each other strongly, or are attracted but constrained from touching by a tensile member, such as a string or cable.
Fighting the forces of gravity and friction is one of the things that magnets do best [ 1 ]. Magnetic levitation is a method by which an object is suspended in the air with no support other than magnetic fields. The fields are used to reverse or counteract the gravitational pull and any other counter accelerations. Maglev can create frictionless, efficient, far-out-sounding technologies. The principle of magnetic levitation has been known for over years, when American scientists Robert Goddard and Emile Bachelet first conceived of frictionless trains.
But though magnetically levitated trains have been the focus of much of the worldwide interest in maglev, the technology is not limited to train travel [ 2 ]. Maglev usages from view point of engineering science can be categorized and summarized as follows: i transportation engineering magnetically levitated trains, flying cars, or personal rapid transit PRT , etc. The test bed can be used as a platform for control theory and maglev work.
The completion of the project demonstrates the feasibility of magnetic levitation for any number of diverse applications.
The test bed is capable of levitating a small steel ball at some stable steady-state position. The control system uses this information to regulate the electromagnetic force on the ball. The system separates into two main subsystems. The amplifier is powered by the DC power supply and based on its input control signal sends a range of current through the coil.
This system operates by measuring light intensity as the levitated ball shields the light source opposite of the sensor Figure 2. To enhance the behavior of the sensor, a light shield with a vertical slit opening is placed around the photocell. These subsystems are mounted together on a base plate to form the test bed. This configuration allows for portability of the system and rigid but adjustable positioning of the components. Figure 3 shows the basic system setup with physical subsystem interfaces.
In order to design a suitable controller for the maglev system, the subsystem components must be modeled or characterized. Over a larger range, sensor readings become very nonlinear. The force actuation subsystem is modeled experimentally by measuring the forces applied to the ball as a function of the coil current and vertical ball position.
This force is measured using an S-beam load cell. Within the small range of travel allowed by the sensor, magnetic force as a function of current is approximately linear.
The plant model for the maglev system is just the ball mass under the influence of external forces. Figure 4 shows the basic control system setup of the magnetic levitation system.
Its magnetic field creates an upward attractive force on any magnetic object placed below. A position sensor detects the vertical position of the object and passes this information to the controller. The controller then adjusts the current to the electromagnet actuator based on the object position to create a stable levitation.
Using the force, plant, and sensor models discussed previously, a closed loop control system can be designed Figure 5. A lead-lag controller is chosen to stabilize the system. This linearized controller is able to hold the steel ball in stable levitation Figure 6 [ 3 — 6 ].
Superconductors produce a supercurrent that creates a perfect mirror of a constant magnets poles. This mirror provides the magnet with a stable repulsion that causes the magnet to levitate called the Meissner effect. The superconductor, in order to have zero electrical resistance, must be cooled in liquid nitrogen.
Without resistance the superconductor is able to mirror the constant magnet almost instantly. This allows the magnet to be able to spin, wobble, or bounce without the magnet shooting away or slamming to the ground.
Applying a voltage across a wire leads to an electric current in the wire. The moving disk is analogous to an electron moving through a lattice of ions the pegs. The gravitational pull on the disk, when the board is tilted, which leads to the disk falling through the array of pegs is analogous to applying a voltage difference to move electrons through a material.
As the disk falls through the array, the disk scatters off the pegs and slows down, in analogy with the way that electrons scatter off the ions in a material.
The electron scattering events lead to a resistivity—an intrinsic property of the material related to the frequency of these scattering events which resist the flow of the electrons.
Now, if we remove all the pegs, the disk will fall unimpeded. This unimpeded flow is exactly analogous to what happens when a material becomes superconducting—electrons no longer scatter. Some materials become superconducting below a critical temperature , which is different for each material.
A material which becomes superconducting below a certain temperature has a resistivity which goes to zero below , and electrons flow unimpeded. Zero resistivity below is the hallmark of superconductivity which was first discovered in by Kamerlingh Onnes for the element mercury below 4. Not surprisingly, this discovery occurred three years after Onnes first liquefied helium in A second salient feature of superconductivity involves magnetic behavior known as the Meissner effect.
When a magnetic field is applied over a superconductor at temperatures above , magnetic field lines penetrate directly through the material just as magnetic fields penetrate through any standard material such as paper or copper.
However, when the material is cooled through and enters the superconducting state, magnetic field lines are expelled from the superconducting material assuming a small enough magnetic field strength Figure 9. This is what is known as the Meissner effect.
Although the initial resistive properties of superconductors were discovered in , the Meissner effect was not discovered until years later in by Meissner and Oschenfeld.
A form of maglev called diamagnetic levitation can be used to levitate light materials, water droplets, and even live animals. It has been used to successfully levitate a frog in The magnetic fields required for this are very high, typically in the range of 16 tesla. The Meissner effect corresponds to perfect diamagnetism for small enough magnetic fields.
Diamagnetism is a property of many materials; when an external magnetic field is applied to a diamagnetic material, the diamagnetic material sets up its own internal magnetic field to partially cancel the externally applied field.
The diamagnetic properties of water have been shown through impressive demonstrations where strawberries and frogs have been levitated in air above strong magnets. The macroscopic properties of superconductors have led to a number of applications—some in present use and some being developed for future use.
Levitating strawberries and frogs are impressive but not particularly useful. However, superconductors are being used in the development of magnetic levitating trains, such as in the Yamanashi Maglev Test Line in Japan. The expectation is that trains will be able to reach higher speeds and utilize less energy if the trains move without friction—thus providing efficiency in travel time and energy usage.
These magnets are free of the expense of supplying electrical power to the magnet, which its power is now required for all large magnets made of resistive wire. Indeed, if one were to take a loop of superconducting wire and were to set a current flowing in this wire, it would continue to flow virtually forever. A study conducted in found that the time for dissipation was well over , years. This means is that, unlike for a copper wire, one would not have to have a battery continuously connected to the wire to maintain the flow of current.
Combining several of these superconducting wire loops on top of one another, one can create an electromagnet. Utilizing a property of superconductors we have not yet mentioned and will not touch in the rest of this thesis, superconductors can also be used to create very sensitive magnetometers with the ability to measure very small magnetic fields of order 10—15 tesla.
These magnetometers have been used in magnetoencephalography MEG which studies the magnetic fields generated by the human brain.
Finally, superconductors can be used to store energy efficiently. The demand on power stations varies significantly during the course of a day with the smallest demand during the late evening and early morning hours.
If during the times when demand is smallest, power stations could generate and then store energy without any dissipation, this would lead to increased efficiency and significant savings. A few of these systems are used at present as the technology continues to be developed. It seems that further progress will be needed because there is still a high cost associated with cooling the present superconducting systems. The hope is eventually to create better superconductors which do not need to be cooled to very low temperatures.
Superconducting technology would then become widely applicable. So far we have mentioned the salient macroscopic features of superconductivity zero resistivity and the Meissner effect as well as how those features can be used in technological applications. Both phenomenological and microscopic theories have provided insight into superconductivity. In , Bardeen, Cooper, and Schrieffer formulated a microscopic theory of superconductivity now known as BCS Theory which could derive the macroscopic properties of superconductors starting from pairing of electrons below.
Due to the successes of this theory, the scientific community generally viewed superconductivity as a well-understood phenomenon. However, in , this all changed due to a new discovery. A critical temperature above the maximum set by BCS theory indicates that something different occurs on the microscopic level.
To this date, the microscopic mechanism for these superconductors is not known. The purpose of this thesis is to garner additional insight into these high-temperature superconductors on a microscopic level with the ultimate aim that this research will lead to a microscopic theory for high-temperature superconductors.
Understanding high-temperature superconductors has important technological implications, both because of the higher transition temperatures as well as the ability to carry larger currents than wires of comparable size made out of copper. The higher transition temperatures mean that these superconductors can be cooled below their transition temperatures more easily than conventional superconductors. Liquid helium is the standard way to cool conventional superconductors below.
Liquid helium is both expensive and not widely available. The ability to push larger currents through high-temperature superconductors also has an advantage in terms of creating smaller wires as well as more powerful magnets. Because STM can probe materials on the atomic level, this technique naturally lends itself to the search for how high-temperature superconductors work on the microscopic level. The entirety of this thesis focuses on the application of STM to high-temperature superconductors and the insight it brings.
This section is intended to give the nonphysicist a glimpse of how STM works and the information it can provide. In STM, we bring an atomically sharp tip a few angstroms from an atomically flat surface. Applying a voltage between the tip and sample leads to a tunneling current flowing between the two Figure This current is very sensitive to the tip-sample distance.
A larger distance between the tip and sample leads to a smaller current. Hence, as we scan the tip over a surface, the rises and falls in the surface topography the rises and falls as we go over atoms are easily captured.
Researchers are interested in studying this gap in the density of states of high-temperature superconductors, both as a function of position as well as of temperature. Because the STM has atomic resolution, they can study how this gap changes from one atom to the next.
The STM has the ability to vary temperatures, and hence they can study how the density of states evolves with temperature both below and through. With the information from these studies, they gain insight into the superconducting state of high-temperature superconductors see Figures 11 and 12 [ 7 ]. Among useful usages of magnetic levitation technologies, the most important usage is in operation of magnetically levitated trains.
Maglev trains are undoubtedly the most advanced vehicles currently available to railway industries. Maglev is the first fundamental innovation in the field of railroad technology since the invention of the railroad.
Magnetically levitated train is a highly modern vehicle. Maglev vehicles use noncontact magnetic levitation, guidance, and propulsion systems and have no wheels, axles, and transmission. Contrary to traditional railroad vehicles, there is no direct physical contact between maglev vehicle and its guideway.
These vehicles move along magnetic fields that are established between the vehicle and its guideway. Conditions of no mechanical contact and no friction provided by such technology make it feasible to reach higher speeds of travel attributed to such trains. The replacement of mechanical components by wear-free electronics overcomes the technical restrictions of wheel-on-rail technology.
Application of magnetically levitated trains has attracted numerous transportation industries throughout the world. Magnetically levitated trains are the most recent advancement in railway engineering specifically in transportation industries. Maglev trains can be conveniently considered as a solution for transportation needs of the current time as well as future needs of the world.
There is variety of designs for maglev systems and engineers keep revealing new ideas about such systems. Many systems have been proposed in different parts of the worlds, and a number of corridors have been selected and researched [ 8 ].
Rapid increase in traffic volume in transport systems plus the need for improving passenger comfort have highlighted the subject of developing new transport systems. One of the important systems which have attracted industries is maglev transport system. In this regard, maglev transport system turns out to be a proper choice for transportation industries around the world.
Maglev systems have been recently developed in response to the need for rapid transit systems. The maglev system comes off clearly better and surpasses high speed railways HSRs in almost most fields. These include the pollution, noise emission, vibration level, environmental issues, land occupations, loading, speed, acceleration and deceleration, braking, maintenance costs, passenger comfort, safety, and travel time.
With the maglev guideway it is also possible to reach to the minimal radiuses for the horizontal and vertical curves.
A maglev vehicle can as well travel at the steeper gradients compared with the HSR systems. This considerably reduces the total length of track for the maglev routes compared to the HSR systems. The possibility of traveling with the higher grade angles also reduces the number of tunnels that are required to travel through the mountainous areas. This can also shorten the total length for the maglev route.
Therefore, construction of the maglev routes in the hilly areas, in addition to many other advantageous of these systems, can be considered as an attractive choice for the transportation industries.
The lower energy consumption of the maglev vehicles in comparison with the HSR systems is also among major characteristics of the magnetically levitated trains. This can be easily associated with the absence of the wheels and the resulting situation of no physical contact between the maglev vehicle and its guideway.
Therefore, the energy loss due to the unwanted friction is out of the equations. Furthermore, the vehicle weight is lower due to the absence of wheels, axles, and engine. On the other hand, reduction in the travel time considerably reduces the energy consumption. The limited energy resources that are currently available to the nation have highlighted the fact that every individual has to be the energy conscious.
The government had to take steps, and it started by setting the preventative rules and the tightening access to the cheap energy resources.
Clearly, the widespread application of the magnetically levitated trains for the public transport, in short and long distances, can provide the nation with huge saving in the energy consumption.
This is not a fact that can be easily ignored nor can it be bypassed [ 9 , 10 ]. There are varieties of vehicles that are manufactured based on these two types of systems. Basically, there are two main elements in a maglev system including its vehicle and the guideway. The three primary functions in maglev technology are levitation, propulsion, and guidance.
Magnetic forces perform all of these. Magnets are used to generate such magnetic forces. Performance of EMS system is based on attractive magnetic forces, while EDS system works with repulsive magnetic forces. In EMS system, the electromagnets on the vehicle interact with and are attracted to levitation rails on the guideway.
Electromagnets attached to the vehicle are directed up toward the guideway, which levitates the vehicle above the guideway and keeps the vehicle levitated. Control of allowed air gaps between the guideway and vehicle is achieved by using highly advanced control systems.
Figures 13 and 14 show the components of the guideway and track, including beam and levitation and guidance systems in aforementioned maglev systems [ 11 ]. Maglev is a system in which the vehicle runs levitated from the guideway corresponding to the rail tracks of conventional railways by using electromagnetic forces between superconducting magnets on board the vehicle and coils on the ground.
The levitation coils are installed on the sidewalls of the guideway. When the on-board superconducting magnets pass at a high speed about several centimeters below the center of these coils, an electric current is induced within the coils, which then act as electromagnets temporarily.
As a result, there are forces which push the superconducting magnet upwards and ones which pull them upwards simultaneously, thereby levitating the maglev vehicle. The levitation coils facing each other are connected under the guideway, constituting a loop. When a running maglev vehicle, that is a superconducting magnet, displaces laterally, an electric current is induced in the loop, resulting in a repulsive force acting on the levitation coils of the side near the car and an attractive force acting on the levitation coils of the side farther apart from the car.
Thus, a running car is always located at the center of the guideway. A repulsive force and an attractive force induced between the magnets are used to propel the vehicle superconducting magnet. The propulsion coils located on the sidewalls on both sides of the guideway are energized by a three-phase alternating current from a substation, creating a shifting magnetic field on the guideway.
The on-board superconducting magnets are attracted and pushed by the shifting field, propelling the maglev vehicle. The guideway is the structure that maglev vehicles move over it and are supported and guided by it. Its main roles are to direct the movement of the vehicle, to support the vehicle load, and to transfer the load to the ground.
It is the function of the guideway structure to endure applied loads from the vehicle and transfer them to the foundations. It is the main element in maglev system and holds big share of costs for the system. It is vital for maglev trains [ 12 ]. Maglev train levitates over single or double track guideway.
Guideway can be mounted either at-grade or elevated on columns and consists of individual steel or concrete beams. Elevated guideways occupy the least amount of land on the ground.
Moreover, with such systems there is guarantee of meeting no obstacle along the route. To guarantee safety for maglev trains necessitates guarantee that there will be no intersection between guideway and other forms of traffic routes.
To serve the purpose, general proposition is to have elevated guideways. Guideway provides guidance for the movement of the vehicle, to support the vehicle load, and to transfer the load to the ground. In maglev guideways contrary to traditional railroad tracks, there is no need to ballast, sleeper, rail pad, and rail fastenings to stabilize the rail gauge.
Guideway consists of superstructures and substructures. A guideway consists of a beam girder and two levitation guidance rails. Guideways can be constructed at grade ground-level or elevated including columns with concrete, steel, or hybrid beams.
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