THE PROTON PRECESSION MAGNETOMETER
The proton precession magnetometer is most commonly used for land-based magnetic surveys.This magnetometer only measures the total amplitude (size) of the earth magnetic field. Usually these type of measurements are referred to as total field measurements.
The proton precession magnetometer is so named because it utilizes the precession of spinning protons or nuclei of the hydrogen atom in a sample of hydrocarbon fluid to measure the total magnetic intensity. The sensor component is a cylindrical container filled with a liquid rich in hydrogen atoms surrounded by a coil.kerosene, alcohol and water are the commonly liquids used. On closing the switch a DC current from the battery is directed through the coil, producing a relatively strong magnetic field in the fluid filled cylinder. The hydrogen nuclei (protons) behave like minute spinning dipole magnets ,become aligned along the direction of the applied field(i.e along the axis of the cylinder).
Upon opening the switch the power is cut to the coil, given that the earth magnetic field generates a torque on the aligned, spinning hydrogen nuclei, they begin to precess around the direction of the earth total field.As the protons precess,the precession produces a time varying magnetic field which induces a small alternating current in the coil such that the frequency of precession of the nuclei is equal to the frequency of the AC current.The proton precession measures the frequency of the oscillatin field and since its equal to the precession frequency of the protons it can be used to determine the strength of the external field.
The proportionality constant which relates frequency to field intensity is a well-known atomic constant the gy...
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...xhibit the usually pattern common to a small magnet as shown below in fig 1.
The direction of the field lines at the equator is horizontal while at the north and south magnetic poles its vertical.This geometry is important in interpretation of magnetic anomalies.The earth total field intensity is not perfectly asymmetric about the geographical northpole eg the north magnetic pole in northern Canada is more than 1000miles from the geographical pole.
The earth cannot be exactly represented by a single bar magnet but has numerous higher order poles and very large –scale anomalous features owing to unknown characteristics of the generating mechanism in the earths core. As shown in fig 1 the solar wind or constant flux of particles and electric currents from the sun distort the field lines.The deviation from asymmetric field is the anomalous set of features in the
Feldstein, Y. I. (2013, November 20) "Some problems concerning the morphology of auroras and magnetic disturbances at high latitudes.” retrieved from:http://en.wikipedia.org/wiki/Aurora_(astronomy)
During the late 1970's, the world of diagnostic imaging changed drastically due to the introduction of Magnetic Resonance Imaging, also known as MRI. For over 30 years, they have grown to become one of the most significant imaging modalities found in the hospitals and clinics ("EDUCATIONAL OBJECTIVES AND FACULTY INFORMATION"). During its ancient days, these machines were referred to as NMRI machines or, “Nuclear Magnetic Resonance Imaging.” The term “nuclear” comes from the fact that the machine has the capability of imaging an atom's nucleus. Eventually, the term was dropped and replaced with just MRI, because “nuclear” did not sit well with the public view ("EDUCATIONAL OBJECTIVES AND FACULTY INFORMATION"). Many people interpreted the machine to produce an excess amount of radiation in comparison to the traditional X-ray machine. What many of them were unaware of, MRI does not disperse a single ounce of ionizing radiation making it one of the safest diagnostic imaging machine available to this date. MRI machines actually use strong magnetic fields and radio waves to produce high quality images consisting of precise details that cannot be seen on CT (Computed Tomography) or X-ray. The MRI magnet is capable of fabricating large and stable magnetic fields making it the most important and biggest component of MRI. The magnet in an MRI machine is measured on a unit called Tesla. While regular magnets commonly use a unit called gauss (1 Tesla = 10,000 gauss). Compared to Earth's magnetic field (0.5 gauss), the magnet in MRI is about 0.5 to 3.0 tesla range meaning it is immensely strong. The powerful magnetic fields of the machine has the ability to pull on any iron-containing objects and may cause them to abruptly move with great for...
The MRI works by using hydrogen atoms’ magnetic properties within the human body to produce high quality images. These protons of the hydrogen atoms can be look upon as bar magnets, in normal situations, they will flow inside...
The traditional theory about the Earth’s core suggest that the core of the Earth is a solid nickel and iron sphere surrounded by a fluid metallic magma. The rotation of the Earth is believed to create massive columns of magma to swirl in the core. These columns are believed to produce the Earth’s magnetic field. This theory is based on the assumption that the Earth’s core is cooling and will eventually cool completely and cease to produce energy and a magnetic field. However, this theory does not answer many ongoing mysteries about the Earth, such as why the Earth’s magnetic field periodically shuts down, and questions about the energy production of the Earth. It was apparent that a new theory was needed to explain the mystery of the Earth’s core.
This is known as an electromagnet. The current passing through an electromagnet produces a magnetic field. Therefore, the more turns of the coil you have, the greater the magnetic field. and the stronger the electromagnet. This will mean more paper clips.
Magnetic Field: The Earth has a superior magnetic field due to a core consisting of iron and nickel. Currently the rotation of the Earth and its Coriolis effect help to create this pull of the tides from the oceans. The northern lights or lurora Borealis can be seen at various times in a mystifying view of beauty.
A metal detector is made up of an oscillator that produces an alternating current. This current will pass through a coil, generating an alternating magnetic field. If an electrically conductive metal part comes near to the coil, Foucault currents or eddy currents will be made of the metal, and this will produce a magnetic field. The other coil, which is functioning as a magnetometer, is used to evaluate the magnetic field, the alteration in the magnetic field can be detected because of the metallic object.
...compasses to go haywire. Even less logical explanations such as alien attacks or particles from the city of atlantis affecting the magnetic field, exist, and are believed by some people. Other theories such as pirates, time vortexes, and methane hydrates are also thought to be a cause(http://adventure.howstuffworks.com/bermuda-triangle8.htm).
The phenomenon called electromagnetic induction was first noticed and investigated by Michael Faraday, in 1831. Electromagnetic induction is the production of an electromotive force (emf) in a conductor as a result of a changing magnetic field about the conductor and is a very important concept. Faraday discovered that, whenever the magnetic field about an electromagnet was made to grow and collapse by closing and opening the electric circuit of which it was a part, an electric current could be detected in a separate conductor nearby. Faraday also investigated the possibility that a current could be produced by a magnetic field being placed near a coiled wire. Just placing the magnet near the wire could not produce a current. Faraday discovered that a current could be produced in this situation only if the magnet had some velocity. The magnet could be moved in either a positive or negative direction but had to be in motion to produce any current in the wire. The current in the coil is called an induced current, because the current is brought about (or “induced”) by a changing magnetic field (Cutnell and Johnson 705). The induced current is sustained by an emf. Since a source of emf is always needed to produce a current, the coil itself behaves as if it were a source of emf. The emf is known as an induced emf. Thus, a changing magnetic field induces an emf in the coil, and the emf leads to an induced current (705). He also found that moving a conductor near a stationary permanent magnet caused a current to flow in the wire as long as it was moving as in the magnet and coiled wire set-up.
It converts the mechanical energy of the rotating shaft caused by wind into electrical energy (Correla, 1986). The focus of this research will be limited to devices that operate as electrical motors.... ... middle of paper ... ...
The Earth is a home for mankind, a planet sustaining life, and it is also a giant magnet! Magnets in general, no matter what type of magnet it is, have two end faces called poles. Poles are where the magnetic force is most effective. These two poles are known as the north pole and the south pole. Magnets also create a magnetic field from the particles within the magnet. The Earth resembles this same structure. The earth has a geographic north pole and a geographic south pole. Since opposites attract in magnets the south pole of the core of the earth points towards the geographic north pole of the earth and the north pole points towards the geographic south pole of the earth. The core of the earth serves the same purpose as the particles in m...
This voltage is concentrated in the coil of the read head, and can be interpreted as the data stored on the magnetic disk. When the direction of the flow of electric current is reversed, the magnetic field’s polarity is reversed. The head is mounted in a “slipper” (or holder) positioned above the disk at 0.5-2.5 microns from the surface. When the disk is revolving around its axis, an air current creates a velocity gradient between the surface and air. This creates enough lift to oppose the spring, pressing the head towards the disk.
Electric currents produce magnetic fields, they can be as small as macroscopic currents in wires, or microscopic currents in atomic orbits caused by electrons. The magnetic field B is described in terms of force on a moving charge in the Lorentz force law. The relationship of magnetic field and charges leads to many practical applications. Magnetic field sources are dipolar in nature, with a north and south magnetic pole. The magnetic field SI unit is the Tesla, it can be seen in the magnetic part of the Lorentz force law F magnetic = qvB composed of (Newton x second)/(Coulomb x meter). The smaller magnetic field unit is the
A magnet also has two poles, called the north pole and the south pole. Although these poles appear the same, they act differently. If two magnets are close together, you’ll observe that unlike poles attract each...