How Do You Change The Bulb In An Air Technology Xray Eraser

Chapter 6     Mod Applied science

Science explains many phenomena and the ways that the things work.  By the scientific theories and the nature of matters, they bring a lot of changes in our lives and raise our standard of living.  For example, scientists invented many useful tools in medical field that are valuable of diagnosing and treating illness and injury. The invention of magnetically levitated trains and optical fibre reduces the altitude betwixt peoples.  Photocopier, inkjet printer, fax automobile and scanner enhance the efficiency of business operations.   In this affiliate, we will discuss the physics behind these tools or apparatus.

Photocopier

The chugalug (pulsate) within the photocopier is made of photoconductor which control the placement of static electricity.

The internal components in a photocopier [ii].

In order to brand a copy of the original newspaper, identify it over the glass surface.  So the photoconducting belt (platen drum) is charged positively (but for some models it is negative) past rolling it with corona wire.  The following discuss concerns a positively charged chugalug(drum). Light shines on the original.  The blackness region of the paper block the light and the static electricity remains in this area while the calorie-free is reflected in the white region and the photoconductor (i.e. the chugalug) has conducting electrons to neutralize the positive charge when light shines on it. No charge remains in this area and forming the accuse image on the belt (pulsate).  The positively charged region of the belt (drum) attracts the negatively charged toner particles.  Identify a white paper to make the reproduction and charged past corona wire.  The negatively accuse toner is attracted by the newspaper and grade the image.  Then information technology is heated and pressed to fuse the paradigm onto the paper creating the final copy.  The charge epitome left on the drum is erased by exposing under charge erase lamp and the toner is removed by the cleaner.  Now it is ready to brand another copy by repeating the procedures.

Diverse photocopier drums consisting metal roller covered with a photoconducting material layer made of semiconductor such as selenium, germanium or silicon.

Corona wires subjected to a loftier voltage transferring to the drum and paper in the grade of static electricity.

A strong lamp illuminates the original to exist copied.  A mirror is used to reflect light passing through a lens onto the drum.  Past adjusting the distance between the lens and the pulsate, the size of the original image can be reduced or magnified.

Static Electricity

Static Electricity is used in the copier to arrange the toner particles on a belt (drum) and transferring to the paper.  It can exist generated by Van der Graaff generator with a roller made past a piece of nylon covered with silicon tape. Since all matters are made upwards of atoms consisting of nucleus (neutrons and protons) and electrons in the surrounding shell.  If the number of protons and electrons are not balanced, the atoms is charged.  Different materials have different strength to concur the electrons.  When two non-conducting materials rub to each other, ane material may capture electron from the other material and becomes charged.  When they are separated, the accuse imbalance between these two materials produces the static electricity.  The static electricity tin can brand someone�south hair stand on end. Demonstration of Van der Graaff generator [iii].

How Things Work

Why does the paper always hot when they come out of the photocopier? The paper passes through the fuser which is a pair of heated rollers before coming out from the photocopier.  The heat will melt the toner powder and the toner then fusing with the fibre of the paper.  Finally, the finished copy is rolled to the output tray.  The temperature of the finished copy will not be as well hot considering the speed of the newspaper rolling over the fuser is very fast, otherwise, it will burn down up due to the high temperature of the fuser.

Printer

Inkjet Printer

An inkjet printer is the printer that create image by placing extremely small droplets of ink onto newspaper.  The dots are small-scale, most 50-60 microns in diameter which is smaller than the diameter of human being hair (70 microns).  The resolution is well-nigh 1440 ten 720 dots per inch (dpi).  It may accept different colours combining together to form a dot, creating photo-quality images.  Inkjet printers accept impress caput with 300 to 600 firing chambers which are tiny nozzles used to spray thousands of droplets of ink per second in a precise pattern to make upwardly the text and images on a page.  There are two types of inkjet technologies to squirt the ink droplets, thermal bubble printing technology and piezoelectric printing technology.

View of the nozzles on a thermal bubble inkjet impress caput [i].

Thermal bubble press

It uses heat to create a tiny bubble in the firing chamber forcing out an ink droplet.

• The printer estrus a small-scale quantity of ink by passing an electrical charge through a resistor.  The temperature of ink reaches 900^oF in a short time interval.
• The heating chemical element vaporizes a tiny layer of ink for a few millionths of a second to create a bubble.  Some of the ink is then pushed out of the nozzle.  The whole process takes near 10 millionths of a second.
• The heating element cools down and the bubble  collapses, creating suction that draws more ink into the print head from the ink cartridge.

Each impress head has many tiny nozzles that can fire ink aerosol simultaneously.

Piezoelectric printing

It uses a piezoelectric crystal, which bends when an electric charge is practical to fire the ink drib onto the newspaper.

• A piezoelectric crystal is located at the dorsum of the ink reservoir of each nozzle.  When an electric charge is applied, the crystal vibrates and changes its shape.
• When the crystal vibrates inwards, a tiny amount of ink is forced out of the nozzle.
• When the crystal vibrates outward, deflects away from the chamber creating suction to pull more ink into the reservoir to replace the ink sprayed out.

The reward of this press technology is that the quantity of ink in the droplet tin can be precisely controlled past adjusting the electric charge applying on information technology.  Larger charges causes larger deflection producing larger droplets while smaller charge produce little droplets.

The sequence of events taking place after yous click OK button for press:

1. The software application you lot are using sends the data to the printer driver through the connection interface (parallel, USB-Universal Due southerial Bus, etc).  The printer driver translates the data into a format that the printer can understand and checks to encounter whether the printer is available to impress or not.
2. The printer receives the data from the computer and stores a certain amount of data in a buffer.  Storing data in a buffer allows the calculator to finish the printing procedure chop-chop instead of having to wait for the actual page to print.
3. If the printer has been idle for a period of time, the printer will normally go through a short make clean cycle to make sure the print caput is clean and set up for press.
4. Paper feed stepper motor is activated to feed a sheet of newspaper from the paper tray into the printer past rollers.  If there is no newspaper in the tray to depress the trigger, the printer lights up the "out of paper" LED and sends an alert to the computer.
5. Print head stepper motor uses a chugalug to movement the print caput assembly beyond the page once the paper is fed into the printer.  The motor pauses for a fraction of a second each time that the impress head sprays ink droplets on the page.  Multiple dots tin be made at each stop with precise amounts.  This stepping happens in a fast speed that information technology seems like a continuous motion.
6. The process continues until the page is printed.  The fourth dimension information technology takes to print a page varies with the complexity of the page and the size of whatever images on the page.  For example, a printer is able to  impress 16 pages per minute (PPM) of black text simply takes several minutes to print a full colour page sized prototype.
7. The print head is parked after printing and the paper feed stepper motor spins the rollers to button the completed folio into the output tray.  Most printers use fast-drying inks and so it is not necessary to expect for a long time before picking up the sail.

Light amplification by stimulated emission of radiation printer

Light amplification by stimulated emission of radiation printer uses a laser beam to write letters or draw pictures on newspaper by sending information from the figurer.  What is the scientific principles using in the laser press process?  We volition discuss this mystery in this department.

The principle used in a laser printer is static electricity.  Initially, the photoreceptor drum is charged positively past corona wire by applying an electrical current on it.

Then the printer shines a tiny laser axle beyond the surface according to the data sent by the computer, i horizontal line at a time.  The laser beam shines low-cal on the pulsate for dot and light off for empty space on the page.  The laser beam does not movement itself but shines light through a movable mirror instead.  The lite discharge certain points on the photoreceptor pulsate and form an electrostatic image.

Later on the blueprint is set, the toner stored in a toner hopper is gathered past the developer unit.  The positively charged toner clings to the discharged areas of the drum merely non to the positively charged groundwork (surface area with no light shine on).

A sheet of paper (with stiff negative charges) is moving forth the belt and rolls over the drum with affixed toner powder design.  The paper pulls the toner pulverization away from the drum and picks up the epitome pattern fixed past the fuser.  Then the finished copy is rolled to the get out tray.

Comparison of laser printer with photocopier

Laser printers work the same basic mode as photocopiers, with a few significant differences.

1. A photocopier scans an epitome by reflecting a bright light off of it, while a light amplification by stimulated emission of radiation printer receives the prototype in digital form.
2. The electrostatic image is created past different ways:
   • For the photocopier, light bounces off a piece of paper and reflects back onto the photoreceptor from the white areas but is captivated past the night areas. The background is discharged. This method is called "write-white".
   • For the laser printer, the process is reversed.  The light amplification by stimulated emission of radiation discharges the lines of the electrostatic image and leaves the background uncharged. This method is called "write-black".

Medicine

X-rays

How Things Work

How X-rays test works? How X-rays is used to encounter inside the body?  What is the difference about bones and tissues that basic appear white in an X-ray prototype while tissues announced dark? X-rays are electromagnetic waves with loftier energy.  They are produced in a vacuum-filled tube, 10-ray tube.  An X-ray tube is an evacuated glass envelope within which a coiled tungsten filament [1] (the cathode) acts every bit a source of electrons.  A low voltage [2] heats the filament, "boiling" electrons off its surface.  These are focused and accelerated to loftier speed to around one-half the speed of light by a large voltage [three] betwixt the target [4] (the anode) and the cathode. The electrons collide with the tungsten anode, producing 10-rays via two dissimilar mechanisms: bremsstrahlung and X-ray fluorescence and give out heat as a by-product.  To forbid the heat from building up, a motor [v] spins the target to 3000 rpm: in addition, a layer of oil around the tube helps dissipate the heat.  X-rays sally through an opening in the housing.  Earlier reaching the patient, they pass through a number of adjustable apertures [6], which limit the size of the Ten-ray field according to the size of the picture.  A lamp [vii] and mirror [8] provide a axle of light that coincides exactly with the path of the invisible X-rays: this is used to aim the radiation field. Bremsstrahlung [i] X-ray fluorescence [i] Photoelectric result When the X-rays have enough energy, the photoelectric result happens.  One of the atom's electrons absorbs the Ten-ray photon and is tossed completely out of the atom.  Part of the photon's energy is used to remove the electron form the atom and the balance is given to the emitted electron as kinetic energy.  For the relatively weakly bound electrons in a small atom, the X-ray photon would give the ejected electron a large kinetic energy.  A small atom ordinarily only ignores the passing X-ray.  In contrast, some of the electrons in a large cantlet are quite tightly jump and require most of the X-ray photon'south energy to remove.  These electrons would depart with relatively little kinetic energy.  A large atom is likely to absorb a passing X-ray.  Thus the small atoms found in tissue (carbon, hydrogen, oxygen and nitrogen) rarely absorb medical X-rays, while the large atoms found in os (calcium) absorb X-rays often.  That's why bones cast clear shadows onto 10-ray film and tissue shadows are less obvious.  Ten-ray film [9] is basically the same every bit photographic film, but has greater sensitivity.  It is coated on both sides with emulsion [10] that detects 10-rays and lite alike.  The film is sandwiched betwixt two fluorescent screens [xi], which emit light when they are struck by 10-rays.  The light emitted exposes the film, thereby forming a more than intense image than Ten-rays alone.  In a higher place the picture show is a grid of many tiny holes [12].  This allows through those X-rays that have passed straight through the body [13], simply non those that accept been scattered-deflected by structures inside the patient [xiv].  These scattered rays would otherwise blur the epitome.

CT scanner

How Things Piece of work

How can a CT scan prove a cross-exclusive view of a living person? Computed tomography (CT) scan is used to determine exactly where things are located inside a patient.  It can separate the superimposed internal structures of image obtained from simple radiographs which are difficult to interpret.  An Ten-ray beam is passed through a thin piece of the body and is detected past a depository financial institution of detectors every bit it emerges.  The beam is then rotated around the subject field, and another exposure made until the same piece has been surveyed from all angles.  The scanner then shifts the patient'southward body to piece of work on the adjacent slice.  A estimator reconstructs and image of the piece past mathematical method.  Many slices can exist stacked on screen to from a three-dimensional view of a patient's internal organs. A scanned liver slice [i]

Using Ten-ray to destroy a tumor

How Things Piece of work

How can X-ray destroy a tumor? When a patient is exposed to 1,000,000eV photons, virtually of the photons pass correct through them but a small fraction undergo Compton handful and leave some of their energy behind.  This energy kills tissue and can be used to destroy a tumor.  By budgeted a tumor from many dissimilar angles through the patient's body, the treatment tin minimize the injury to healthy tissue effectually the tumor while giving the tumor itself a fatal dose of radiations. Compton scattering

The first picture of a baby child

How Things Work

How tin can ultrasound exist used to take the showtime picture of a child before birth? In a medical scanner [B], ultrasound of between 1 and 15MHz are transmitted into the torso, and the returning echoes are detected.  The scan head [C] is fabricated of more than 100 separate piezoelectric transducer elements. Each of these is a block of synthetic piezoelectric textile lead zirconate titanate (PZT).  Under estimator control, these are made to emit audio in a precise sequence.  This produces a highly focused "spot" of sound, which is scanned in a single aeroplane over the fetus [D]. Ultrasound side view image of a growing fetus (approximately 12 weeks old) showing (right to left) the head, neck, torso and legs. [i] By detecting the intensity and return time of the echoes from the boundaries of unlike tissue types, the depth and density of the tissues are revealed.  The intensity of the echo at each indicate of the browse is converted electronically into a shade of greyness, which is displayed on a screen.  Ultrasound is entirely reflected at junctions between tissue and air, but moves well in liquids.  A layer of aqueous gel practical between pare and scan head, and a total float ensure that sound has an air-free path to the fetus. Ultrasound scan tin also be used to detect tumors or fluid-filled cysts.  Relatively large echoes are sent back from organ boundaries, while pocket-sized structures within the tissue give "grainy" low-level echoes which tin can be distinguished from healthy tissue.

Maglev Trains

A Maglev in Shanghai

Maglev train, short for magnetic levitation train, is a new form of ship style that enhances the speed of carrying passengers from one end to another.  It uses the basic principles of magnets floating over a guideway to replace the old steel cycle and track that is a breakthrough of the limitations of friction betwixt the train wheels and its rail.

Forces between Magnets

Suppose magnets are placed at the bottom of a train and over the top of a track facing each other with like poles, repulsion forces exert on one another and support the train without whatsoever direct contact. Analogy of levitation magnets [3]. Band magnets sit around a large wood dowel. The top magnet is pushed down and oscillations are observed. The repulsion becomes stronger as the magnets approach one another and exceeds the railroad train'southward weight.  The train can remain suspended over the rail on a magnetic cushion and forms the magnetic levitation.  Although the height of the train can kept stable, this suspension is unstable in horizontal direction.  If the railroad train is not perfectly centred, the railroad train will tend to slip sideways until it falls.  The merely style to stabilize the train and proceed information technology centred above the track is using adjustable magnets---electromagnet, to push the train back to the centre of the track if information technology starts to fall.  In a latter section, we will introduce a sophisticated command organisation which governs the lateral guidance. The system monitors the train's position and conform the electromagnet to maintain a constant separation between those poles by the information of the current situation.

Electromagnetic induction

A changing magnetic field creates an electric field which pushes on the conductor'south mobile electric charges to move and grade an electric current.  This process is called electromagnetic induction.

Sit-in of electromagnetic induction [iii]

In the above demonstration, a small lite bulb is continued to a large coil of wire.  The coil is moved in and out of a magnet.  This changing magnetic field induces an electric current.  The bulb lights equally the current passing through the excursion. In fact, the current runs in a direction such that a magnetic field is created to oppose the alter. This is the Lenz's police force.

When an alternating current is flowing through a gyre of wire wrapping around an iron cadre, the poles of the electromagnet is reversed by irresolute the direction of electric current flowing.  If an electrical conductor (the metal bar in the to a higher place effigy) is placed virtually the electromagnet,  the magnetic field is so induced on the metallic bar to oppose the changing magnetic field higher up it. It is, of course, due to the induced alternating current in the metallic bar. Simply, a changing magnetic field in the iron cadre turns an electrical usher nearby into a magnet. For example, if the south pole of the electromagnet is virtually the conductor, then the usher becomes magnetic with its due south pole upwardly pointing towards the electromagnet to repel it.   When the current at present reverses the direction changing the pole management with north pole downwards, the conductor becomes magnetic with its north pole upwards to repel the electromagnet.  The currents generated past electromagnetic induction always produce magnetic fields that oppose the magnetic field change.

Prototype of the guideway for the Yamanashi maglev test line in Japan [3]

Maglev train rides above the track by magnetic suspension instead of rolling on wheels conventionally.  The working principles are as follows. [four]

1. The magnetic levitation

   The "8" figured 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 centre of these coils, an electric electric current is induced within the coils, which so act as electromagnets temporarily. As a result, in that location are forces which push the superconducting magnet upwardly and ones which pull them upwards simultaneously, thereby levitating the Maglev vehicle.
   

2. The lateral guidance

   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 strength acting on the levitation coils of the side about the machine and an attractive strength interim on the levitation coils of the side farther apart from the automobile. Thus, a running auto is always located at the middle of the guideway.
   

3. The propulsion

   A repulsive force and an bonny 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 iii-stage alternating electric 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.

   However, the ordinary permanent magnet is heavy and expensive, so most electrodynamic levitation schemes utilize electromagnets instead.  They employ special wires fabricated of superconductors that the currents menstruation perfectly and freely while currents flowing in metal experience frictionlike effects and gradually ho-hum downwardly.  Superconductor can comport like a lite and superstrong permanent magnet at low temperature.  A maglev train using superconducting magnets must be kept common cold to make them magnetic and tin hover easily without requiring much electrical power.
   

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Reference

• Ruppel, Tom, The Way Science Works, New York: Macmillan, 1995.
• Harris, Tom, "How X-rays Work" at www.howstuffworks.com.
• Gould, Todd A., "How MRI Works" at www.howstuffworks.com.
• Freudenrich, Craig C., "How ultrasound Works" at www.howstuffworks.com.
• Bloomfield, Louis A., How things work: the physics of everyday life. New York: John Wiley, 1997.
• Meeker-O'Connell, Ann, "How Photocopier Works" at world wide web.howstuffworks.com.
• Tyson, Jeff, "How Inkjet Printers Work" at world wide web.howstuffworks.com.
• Fountain, Henry, The New York times circuits: how electronic things work. New York: St. Martin's Press, 2001.
• Harris, Tom, "How Laser Printers Work" at www.howstuffworks.com.
• Nave, Rod, Hyper Physics at hyperphysics.phy-astr.gsu.edu/hbase/hframe.html.
• Bonsor, Kevin, "How Maglev Trains Work" at www.howstuffworks.com.
• Bigelow, Ken, Play-Hookey Website at www.play-hookey.com.
• A website of Railway Technical Research constitute at "http://www.rtri.or.jp/rd/maglev/html/english language/maglev_frame_E.html".

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Glossary

Alternating current

An electrical current flowing in the direction that reverses periodically.  While a current flows continuously in one direction called a direct current.

Bremsstrahlung

It refers to cases in which a charged particle accelerates extremely rapidly attracted past the nucleus of an cantlet and emits a very high free energy photon.  In Ten-ray tube bremsstrahlung, a fast-moving electron arcs around a nucleus of a heavy atom and accelerates so abruptly that it loses energy in the grade of Ten-ray photon. The closer the electron comes to the nucleus, the more it accelerates and the more energy it gives to the X-ray photon.  However the electron is more probable to miss the nucleus by a large altitude than to almost hit information technology, so bremsstrahlung is more likely to produce a lower energy 10-ray photon than a college free energy one.

Compton scattering

It occurs when an X-ray photon collides with a unmarried electron and then that the two particles bounce off one some other.  The X-ray photon knocks the electron right out of the cantlet and then scattered away.

Electromagnet

It is a coil of wire that is magnet only when an electric electric current flowing through it.

Electromagnetic consecration

The process of a changing magnetic field induceing an electrical electric current.

Lenz'southward law

Electric current induced by a irresolute magnetic field always produces a magnetic field that opposes the alter.

Photoconductor

It is a material which is an electric conductor allowing electrical charges to motion in the light and beingness an electric insulator preventing any movement of electrical charges in the dark..

Photoelectric event

I of the electrons in an atom absorbs the photon energy and is ejected out of the cantlet.  The energy of the photon is equal to the sum of the energy needed to eject out the electron and the kinetic free energy gained by that electron.

Piezoelectric crystal

It has remarkable properties.  When a voltage is applied, it changes shape; as soon as the voltage is switched off, the crystal snaps back to its original conformation.  An aquiver voltage therefore makes the crystal vibrate, producing high-frequency sound equally it does so.

Correct hand rule

The direction of the magnetic field is perpendicular to the wire and is in the curling direction of your right hand fingers.  The direction of your thumb is the direction of electrical current.

Superconductor

Superconductor is a textile that at low temperature get perfect conductor of electricity.

X-ray fluorescence

The fast moving electron collides with an heavy atom, it knocks out the electrons in i of the inner orbitals  and leaves the cantlet as a positive ion with a vacant orbital.  A college orbital electrons fills the empty orbital and release its excess energy creating Ten-ray photon.

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Useful websites

1. HowStuffWorks
2. The Academy of Minnesota
3. http://hyperphysics.phy-astr.gsu.edu (experimenter: Jennifer Craigo)
4. Railway Technical Inquiry Plant

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Source: https://www.physics.hku.hk/~phys0607/lectures/chap06.html

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