The invisible presentation (10 minutes)

Your group will read the three readings on your area of the EM spectrum.

Presentation requirements

1. What area of the spectrum are we talking about? 2. Label that area on the EM spectrum on the board.

3. Give a brief overview of the technologies or discoveries associated with this area of the spectrum.

4. Pick ONE example of a specific technology that uses these waves and become an expert on it. Present on the following

How this technology works What this technology does 3 uses and/or impacts on society (think what are the benefits and/or negative

consequences of this technology) Be creative use visuals, a skit, rhymes, dances anything you like. It would be a great way to start your presentation by acting out the device being used in

some sort of scenario.

5. Any other interesting facts.

When you are listening: Draw an EM spectrum and add the devices. On the same diagram label 1-2 key points about each device.

Hand in finished product for 10 marks.

1 mark for each device in the correct place. 1 mark for the 1-2 points on each device written below.

Radio is everywhere!

Radio waves silently transmit information all over the world. Discovered in the late 1800s and fundamental in many of the most important technological advances of the 20th century, radio waves are the basis for almost all non-written communication and most wireless technologies. They transmit signals that carry pictures, data, music and conversations invisibly over long distances. Without technology based on radio waves, you might find your day-to-day life nearly unrecognizable.

Many household products we consider necessary depend on radio waves. AM and FM radios, wireless networks, cordless and cellular telephones, radio-controlled toys, television programming, garage door openers and GPS receivers -- all of these, along with countless other devices, depend on silent, invisible radio waves to operate.

Despite their importance, many people have become concerned about the possible negative health effects of excessive radio wave exposure. Specifically, the alleged culprits seem to be cell phones, which transmit their voice and data signals over radio waves, and cell phone towers, which route and receive these signals. Do these technologies cause cancer? Do they affect our brain waves?

Experts disagree about the long-term effects of electromagnetic radiation generated communications infrastructure. However, if there is a problem with cellular technology, it is probably not coming directly from the towers. Any potential danger is likely to be more worrisome for those who personally use cell phones, because the phones are directly against their heads. Also, cell towers operate at low power. This is part of what makes the cell phone system work properly. The level of power from a cell tower is similar to that of a citizens' band (CB) radio. According to the American Cancer Society, the types of radio waves generated by cell phones are unlikely to cause cancer, since they are not ionizing radiation, and they have no ability to alter the DNA of human cells so that they produce cancer [source: ACS].

http://curiosity.discovery.com/question/what-importance-of-radio-waves

How the radio spectrum worksThe radio spectrum is the lower portion of the electromagnetic spectrum.  The radio spectrum is below both the infrared spectrum and the visible spectrum.  The sections of the radio spectrum are called bands.  These bands are subdivided into frequencies and even further divided into channels.  Channels are frequently set aside for certain purposes, but can be changed by one of the regulatory agencies that monitor and regulate the radio spectrum.   Use of the various bands and frequencies is usually determined by individual government agencies on a country by country basis.  In many cases, such as in the United States, these frequencies are leased, sold or licensed to private radio operators. 

Frequency Division

The radio spectrum is subdivided into sub frequencies.  Very low frequencies (VLF) range from 3-30 kHz.  Very low frequencies are used for communication with submarines, heart rate monitors and avalanche beacons.  Low frequencies range from 30-300 kHz are used for navigation signals, AM long wave broadcasting and amateur radio.  300-3,000 kHz are medium frequencies are used for amateur radio and AM medium wave broadcasts.  3,000-10,000 kHz are high frequencies and are used for FM broadcasts, television broadcasts, ground to aircraft communications, maritime mobile communications and weather radio.  Very high frequencies are 30,000 to 300,000 kHz.  Finally, Ultra high frequencies are 300,000-3,000,000 kHz.  These ultra high frequencies broadcast mobile phones, GPS, two way radios, microwave ovens and television broadcasts.

Regulations and Restrictions

All radio transmissions in the United States are monitored and regulated by two separate agencies, the Federal Communications Commission and the National Telecommunications and Information Administration.  The Federal Communications Commission (FCC) regulates the use of the radio spectrum for nongovernmental use.  All use of the radio spectrum by the federal government is controlled by the National Telecommunications and Information Administration (NTIA.)  

The use and redistribution of bands and frequencies can change frequently.  Public use of certain bandwidth can rise to the forefront of public debate when large companies move to purchase the bandwidths or frequencies.  There are a number of groups in the United States that advocate opening access to the radio spectrum, arguing that this would create a greater free market. Opponents of such open access are necessary to prevent any one entity from controlling the spectrum. 

http://www.helium.com/items/2081753-how-the-radio-spectrum-works

The Many Uses Of Radio WavesDiscover the many uses of radio waves and the role radio plays in our lives, from entertainment to medicine.

Radio is one of our most important ways of communicating. Since the late 1800s, when radio was invented, it has played a huge role in our lives. Communication between two far distant places became quick and much more inexpensive than stringing telegraph wire. Suddenly, ship-to-ship and to-shore radios were saving thousands from disaster at sea, radio entertainment broadcasts were going into peoples' homes, and soldiers in the field were able to keep in touch with friendly units.

Broadcasting is the most well known use of radio. Radio stations arrange songs and programs of particular genres to broadcast to listeners who tune in to hear them. Most stations provide short newscasts and talk radio provides a public forum where people can listen to interviews or call in to speak with the host or his or her guests. Sports events can be broadcast as an announcer provides a play-by-play description of the action. Companies can buy ad space on privately owned stations to air commercials designed to appeal to that station's listeners.

Two-way radios are also very important. Emergency personnel such as police, fire fighters, and ambulance crews use radio to stay in contact with their bases and with each other. They send and receive reports with radios in their vehicles and carry smaller portable devices with them. An EMT can send descriptions of wounded individuals ahead to the doctors at a hospital so they can prepare to treat them.

Commercial vehicles such as taxis, trucks, and airplanes use radios to receive directions and report difficulties. Construction crews, farmers, ranchers, and other groups use radio to send and receive information such as instructions and warnings. Radio is used extensively in the military to facilitate communication between bases, ships, planes, military vehicles, and field units. Private individuals may also use radio to communicate with others on citizens band radio.

Other uses of radio include remote controls used to direct toys, railroad cars, or unpiloted aircraft. Airplanes depend on radioed navigation signals to stay on course and a form of radio called radar is used to guide ships, submarines, and aircraft as well as to detect them. Radios may also transmit large amounts of data between electronic devices, such as computers. Devices called bugs allow others to listen in on private conversations to obtain information and are commonly used by intelligence agencies. Doctors can also use radio to diagnose stomach ailments by having the patient swallow a capsule radio and then studying the signals it transmits.

http://www.essortment.com/many-uses-radio-waves-58203.html

OPERATING ON ELF FREQUENCIES

Most of us never venture into the 'basement' of the radio spectrum, yet some amazing and unusual techniques are used down there to communicate with submerged submarines.

In mid-ocean, the only means of communication with a submerged submarine is to use radio in the VLF or ELF bands. The ability of radio signals to penetrate water depends on the following factors:

* the strength of the signal. * the frequency being received. * the efficiency of the receiving antenna. * the salinity of the water surrounding the submarine.

In the middle of the Atlantic Ocean, with a salinity of 3.2 %, a VLF signal will penetrate down to a depth of 10 to 20 meters, barely periscope-depth for a modern day submarine. In areas with less salinity, like the Mediterranean Sea or in the brackish waters of the Baltic Sea, it will be possible to receive the same signal  to a depth in excess of 40 meters. Near the Atlantic coast where the salinity is less due to the run off from fresh water rivers, the receive depth could be even greater.

If cruising too close to the surface, a submarine might compromise it's position to the searching eyes of a spy satellite or A/S aircraft. To achieve one-way, long distance communications with submarines down to about 330 feet or deeper, it is necessary to resort to an Extremely Low Frequency (ELF - 300 Hz to 3 KHz) system. A system such as this is very expensive mainly because of the great length of the antenna. The US 'Austere ELF' system for example, has an antenna some 200 km (125 miles) in length. ELF has two major disadvantages. It suffers from the inevitable natural noise in that part of the spectrum and also has a very low data rate. The Austere system is capable of passing just one three letter group in 15 minutes. With three letters it would be possible to signal some 17,576 codes (26 letters by 26 letters by 26 letters = 17,576). The most important use of the ELF system would be to act as a 'bell ringer' by instructing the submerged submarine to approach the surface and deploy a float or mast mounted antenna to receive a higher level, encrypted HF or satellite signal.

The original plan for the ELF exciter called for a chain of transmitters positioned in a line over 1,000 miles in length, with an antenna working against a well grounded and buried counterpoise. The intent was to couple RF energy directly into the Earth's core at its natural resonant frequency. Since the right-of-way crossed many farms, there were many objections from dairy

farmers claiming that the RF might sour milk so the actual antenna system, as installed, is only a fraction of its original intended length. Even with a 'shortened' antenna, the idea did work since both the USN and the Soviet navy both used the system to reach submerged submarines.

There are two reasons for the very slow data rate. First, at ELF frequencies, the modulation rate must be extremely low. Secondly, the "code" which is sent is a repeated, error correcting code. As a result, the bit rate is few bits per minute repeated until enough data is accumulated to let the receiver decide if a letter has been received successfully. At the end of 15 minutes, it's expected that three correct characters have completed the journey. All messages sent in this manner instruct the submarine to do something which would not be catastrophic if there were an error. (Example - copy the 0800Z schedule NOT launch all nuclear weapons).

In the United States military, the primary means of communicating with submerged submarines is the TACAMO (Take Charge and Move Out) system which uses a fleet of aircraft. Two aircraft are always airborne - one over the Atlantic and one over the Pacific. Other aircraft are stationed on the ground and they are on a 15 minute alert. The aircraft fly 10.5 hour missions, starting at one airfield and ending at another. Random patterns are flown to mislead any unauthorized observers. The TACAMO aircraft can receive and relay signals from a number of different ground command posts. Each aircraft is equipped with a 6.2 mile long trailing wire antenna (wound on a reel) and a 100 kw transmitter operating in the VLF region. When the aircraft has to transmit a message, it banks and proceeds to fly a very tight circle. The causes the trailing wire antenna to hang vertically below. Once the message is transmitted over the VLF downlink the aircraft resumes normal flight.

The TACAMO fleet was initially comprised of the Lockheed Hercules EC130 aircraft, but these are being gradually phased out and replaced with the Boeing 747 AWACS type aircraft. These aircraft have the capability to transmit a 200 kw signal using a 2.5 mile trailing antenna. The systems described above were documented in a book printed in 1985. Due to unavailability of information, I do not know if the same system is still in use in the 1990's, but the techniques, nonetheless are quite intriguing.

Somehow the difficulty of fitting a 160 meter amateur radio antenna in a restricted space seems trivial when compared to the problems of seriously operating on VLF and ELF frequencies.

http://jproc.ca/radiostor/vlfelf.html

Very Low Frequency (VLF) StationsThe S-Meter site continuously receives 24.8 kHz signals in Salt Lake City, Utah, from NLK in Jim Creek, Washington, to detect real-time Sudden Ionospheric Disturbances (SID's).

The Very Low Frequency (VLF) radio spectrum extends from 3 to 30 kHz. Standard communications receivers do not receive signals that low in frequency. Furthermore, most antennas used with standard communications receivers are optimized for higher frequencies and perform poorly in the VLF spectrum. Because of that, few Radio Amateurs or shortwave listeners have ever heard VLF signals and most know very little about the large number of stations in that part of the spectrum, what those stations are used for, or the nature of VLF radio signal propagation.

However, because VLF receivers and receiving antennas are easy to construct, the VLF spectrum attracts a small number of curious and sometimes very dedicated VLF listeners who want to learn more about this little-known and somewhat secretive part of the radio spectrum. The guide below is provided to assist them in identifying stations they receive.

Signals from powerful VLF stations can be received worldwide. They penetrate deep into the earth and deep into the sea (especially in the lower portion of the VLF spectrum) and therefore can be received by submerged submarines. Though some VLF stations have other purposes, the primary function of most VLF stations is to communicate with submerged military submarines or help them navigate underwater.

Worldwide Very Low Frequency StationsFreq. Call Power Description

11.904761 kHz

(None. but nicknamed "Alpha") (Unknown)

This frequency is shared by three currently-active stations (there used to be more) that form part of the Russian Hyperbolic Radio Navigation System (Radioteknicheskaya Systema Dalyoloiy Navigatsii). One is located near the village of El'Ban, Russia. Another is at 45:24:17.9 N 38:09:29.0 E. The third is at 55:45:22.0 N 84:26:52.4 E.

12.648809 kHz

(None. but nicknamed "Alpha") (Unknown) The same locations as other stations nicknamed

"Alpha." See 11.904761 kHz above.13.0 kHz (None) (Unknown) A Royal Australian Navy communication station

located at Gippsland, Woodside, Victoria, Australia (on Victoria's south-eastern coast). The transmitting antenna is 1400 feet (427 meters)

high and is the highest VLF antenna in the world.14.880952 kHz

(None. but nicknamed "Alpha") (Unknown) The same locations as other stations nicknamed

"Alpha."See 11.904761 kHz above.

http://www.smeter.net/stations/vlf-stations.php

Low-Frequency Radio AstronomyOne of the last unexplored frequency ranges in radio astronomy is the frequency band below 30 MHz. This band is scientifically interesting for exploring the early cosmos at high hydrogen redshifts, the so-called dark-ages. This frequency range is also well-suited for discovery of planetary and solar bursts in other solar systems, for obtaining a tomographic view of space weather, and for many other astronomical areas of interest. Because of the ionospheric scintillation below 30 MHz and the opaqueness of the ionosphere below 15 MHz, earth-bound radio astronomy observations in those bands would be severely limited in sensitivity and spatial resolution, or would be entirely impossible. A radio telescope in space would not be hampered by the earth's ionosphere, but up to now such a telescope was technologically not feasible. However, extrapolation of current technological advancements in signal processing and nano/femto satellite systems imply that distributed low frequency radio telescopes in space could be feasible in about 10 years time.

To achieve sufficient spatial resolution, a low frequency telescope in space needs to have an aperture diameter of over 10 to 100 km. Clearly, only a distributed aperture synthesis telescope-array would be a practical solution. In addition, there are great reliability and scalability advantages by distributing the control and signal processing over the entire telescope array. The aim of the OLFAR project is to design a concept study on an autonomous sensor system in space to explore this new frequency band for radio astronomy. The project will develop scalable autonomous nano-satellite prototypes, demonstrated in the lab. The results will be validated by three flight units, which can be launched into space and work as a formation flying radio-astronomy array.

http://ens.ewi.tudelft.nl/Research/array/lofar/intro.php

Infrared RadiationInfrared (IR) radiation is simply one of the many types of 'light' that comprise the electromagnetic (EM) spectrum. Infrared light is characterized by wavelengths that are longer than visible light (4000-7000 Angstroms, or 0.4 0.7 micrometers; also denoted as microns). Astronomers generally divide the infrared portion of the EM spectrum into three regions: near-infrared (0.7 5 microns), mid-infrared (5 30 microns) and far-infrared (30 1000 microns).

Who discovered infrared light, and when did the discovery occur?

The famous astronomer William Herschel, who also discovered the first new planet since antiquity (Uranus) and studied sunspots, was the first to discover a form of light other than visible (optical). In an 1800 experiment, Herschel used a glass prism to spread sunlight into a rainbow of colors. He then measured the temperature of each color of visible light and noted differences. Most intriguingly, he found a curious reading when the thermometer bulb was placed just beyond the red portion of the visible spectrum. He had discovered thermal radiation, which has come to be known as infrared. [The prefix "infra" means "below."]

Is infrared radiation dangerous?

In general, no -- at least from naturally occurring physical processes. Any form of radiation -- including visible light or radio waves -- could potentially be dangerous if highly concentrated into a narrow beam (that is the principle of lasers) of very high power. We are immersed in infrared radiation everyday. It is nothing more than heat. On the other hand, you certainly would not want to place your hand on a hot stove, in which case IR radiation would be dangerous.

What kinds of objects emit infrared radiation?

All objects that are not at absolute zero emit infrared radiation. Absolute zero defines the temperature where all molecular motion ceases, and is the coldest possible temperature. It corresponds to about minus 273 degrees Celsius, or minus 460 degrees Fahrenheit. [Physicists define this point to be zero degrees Kelvin, with each increment on the Kelvin scale identical to that of the Celsius scale.] Even ice cubes emit thermal heat!

How does our atmosphere block infrared radiation from space?

Only certain parts of the electromagnetic spectrum (all light ranging from gamma ray to radio waves) can make it to the Earth's surface. Much is absorbed by our atmosphere. Visible light, radio waves and a

few small ranges of infrared wavelengths do make it through. Gamma rays, and most of the ultraviolet rays and infrared rays do not. Much of the infrared light is absorbed by water vapor in our atmosphere. This is why infrared telescopes are placed on high, dry mountains (like Mauna Kea in Hawaii) so that they can observe more infrared radiation. The only way to study the entire range of infrared (as well as gamma rays, xrays, UV) is to place telescopes in space well above the atmosphere. Only some (not all) of the IR radiation between 1 and 40 microns makes it to the Earth's surface. The rest is absorbed by our atmosphere primarily by water vapor. IR is also absorbed to a lesser degree by carbon dioxide and oxygen molecules.

What materials block, reflect, absorb or emit infrared light?

Thermal infrared, which corresponds to wavelengths longer than about 5 microns is a direct measure of temperature. One simple material that blocks IR is plexiglass. We use it in a demonstration of infrared radiation and the greenhouse effect. Also, water is a good absorber of IR. Hence, one must get above the atmosphere's water vapor to conduct most infrared astronomy measurements. Any good mirror should also be capable of reflecting infrared light. Most ground-based telescopes that observe in the "near-infrared" (betweewn 1 and 2.5 microns) rely on the same telescopes as for optical astronomy. Finally, thermal IR is a measure of heat, and *any* object above absolute zero (-273 C) emits infrared radiation. The hotter a source, the more IR light it emits.

What are the benefits of infrared technology?

There are several advantages to detecting and studying infrared radiation. Infrared is basically heat radiation. Infrared radiation carries information about the temperature distribution of the objects studied. Infrared can also penetrate, thick smoke, clouds and dust. This makes infrared cameras very useful in search and rescue and firefighting. Many lives have been saved by thermal infrared cameras - finding people lost at night or at sea by detecting their body heat, or finding people in a smoke filled building. Infrared is widely used in the sciences in astronomy, meteorology, oceanography and archeology. It is used to inspect mechanical and electrical systems, in animal studies, in medicine, navigation, law enforcement, in the military as well as in food studies.

http://coolcosmos.ipac.caltech.edu/cosmic_classroom/ask_astronomer/faq/radiation.shtml

Infrared Harvest

BORDEAUX — With just one month to go before the first harvest begins in Bordeaux, winegrowers carefully scan the sky and the ground. Some of them have been paying close attention to their mail boxes as well.

Between July 15 and Aug. 15, depending on the season's weather, some growers receive a CD of infrared satellite imagery of their houses. The images are taken from 800 kilometers up, and are shot between 15 and 20 days before the "véraison," the stage when grapes change color. "The technique is amazing," says Patrick Bongard, the director of 14 Gironde region chateaus belonging to the Castel Group, one of the first French wine-producing groups based in the southwest region. (See 50 American wines.)

In partnership with the Wine Cooperative Institute (WCI), a company called Geo-Information Services (GIS), a subsidiary of Astrium Services, has offered a service for the past three years called "noview." The idea is simple: to provide wine growers with a map detailing the vegetative state of their vineyards.

"It helps the winegrower make decisions and save a considerable amount of time," says Jacques Rousseau, the WCI Group's director of wine-producing services. "It allows him to have an instant overall view of his vineyard. He can then know the state of his vineyard as if he had scoured the rows one by one."

This satellite map can determine the uniformity of the ripening process as it takes place in a specific plot of land. The greener the grapes, the stronger the plant surface is; the more red and blue they are, the less developed the vegetation is. From this report, vintner can draw numerous conclusions, including the optimum harvest date.

"For several chateaus we thought the grapes were ripening at a uniform rate, but it's actually not the case," says Patrick Bongard, who has been using noview since 2009. "We decided, therefore, not to harvest some zones at the same time as others, so that we harvest the ripest grapes only. In the end, for every chateau, by carefully selecting the grapes we are able to put 20% of the production into our premium wines." (See "The Fight to Save Wine from Extreme Weather.")

The same goes for Fieuzal, a vintage wine from Pessac-Leognan, the first vineyard in Gironde to implement the high-tech system. "This system helps me chose my grapes better, and harvest different batches at different times," says Stephen Carrier, the director. "Also, I can better define the texture of my wines." A new fermenting room built this year contains vats that correspond to batches of grapes, rather than to full parcels, which is usually the case.

Also, the maps can help vintners confirm or form hypotheses about a host of possible agronomical problems, such as aging vines, poor ground and overuse of plant-care products. With information from the CIV, the winegrower can thus modify his or her growing practices. "All the properties have seen their wine production evolve," says Patrick Bongard.

Since the commercialization of noview, 6,000 acres of vineyards have been photographed each year on behalf of about 50 clients, especially in the south of France. Clients pay 70 euros (about $100 dollars) per acre.

Even major advocates of the technology, however, are quick to point out that good wine depends on a lot more than just satellites and high-tech maps. "We don't want to make winegrowers believe they can run their vineyards from a computer or even from noview," says Jacques Rousseau. "The human expertise remains essential."

http://www.time.com/time/world/article/0,8599,2087901,00.html

Infrared Sauna Heaters

What exactly are far infrared sauna heaters?

Infrared heaters are designed to emit energy in a very specific wavelength — the highly beneficial infrared wavelength.

Energy comes in a range of wavelengths. The visible light we see falls into one section of this range. Ultraviolet rays and x-rays fall into other sections of the range.

While the infrared energy wavelengths range from 5.6 to 1000 microns (one micron equals one micrometer or one millionth of a meter), far infrared sauna heaters are designed to provide infrared waves with a concentration between 6 and 14 microns. FIR wavelengths of between 6 and 14 microns are believed to be the most beneficial to humans and other living things on Earth.

Nowadays, designers try to further fine-tune these heaters to emit energy in the 9.35-12 micron wavelength range. This narrower wavelength range is thought to be ideal for sauna users and maximize the benefits of the infrared sauna . This corresponds to a heat radiation between 98.6-120 degrees F.

DID YOU KNOW?

• The human palm emits far infrared energy between 8 and 12 microns.

• The energy output from quality far infrared sauna heaters so closely match the human body’s radiant energy that nearly 93 percent of the sauna’s far infrared waves reach the skin.

The heaters work when an electrical current is passed through its emitter, an infrared-producing conductive material.

All professionally manufactured saunas have their heaters operated by a control unit. Most of these units are dual control, meaning they can be operated from inside or outside the cabinet. This control unit or brain can be analog or digital and allows the user to program the sauna temperature and set a timer for how long they will be using the heaters.

If you’re planning on building a sauna using a do it yourself sauna kit or a sauna construction plan, you’ll want to review our upcoming sauna kit page for some important considerations on which sauna heater controls to choose. Of all the infrared sauna equipment you will buy, the heaters will be the key to a high quality home sauna.

How do they work?Infrared sauna heaters produce far infrared radiation to directly heat the user, they do not use steam or dry heat like a steam room or dry heat sauna does. Read more about this on our fir saunas page .

The infrared waves don’t heat the air of the sauna as much as conventional sauna heaters do. Instead, they travel through the air until they run into an object (in this case the user). Then, by an energy and heat transfer process called radiation, the waves warm the object.

The heaters are activated by running an electrical current across its emmiter. The electrical current energizes and excites the emmiter and energy is radiated and broadcast from it in the form of heat and light.

A warmed up emitter is sending out FIR waves even when the electricity doesn't sound "on"

Heater manufacturers figure out what specific temperature their emmiter needs to operate at in order to produce the highest quality and concentration of desirable FIR heat. The sauna control panel toggles the heaters on and off to maintain the heaters in their ideal operating range while respecting the sauna user’s requested temperature.

A sauna heater that stays on continously or that operates at a very high temperature, unless specifically designed to do so, is not necessarily producing FIR in the ideal range. When the emitter is at its optimal temperature, with or without a current passing through it, it is broadcasting FIR.

Technical corner: why fir heat waves don’t heat the air as much as conventional sauna heaters do

Of all the sauna parts , understanding the way infrared sauna heaters heat the user is the only complicated part.

Far infrared waves heat objects directly through an energy and heat transfer process called radiation. A simple explanation why quality infrared sauna heaters requires less heat then any other type of sauna to produce more dramatic results is defined by Planck’s law of radiation.

Basically, Planck's law is a formula that calculates the range, quantity, and concentration of wavelengths (frequency) of thermal radiation. Planck’s law tells us that there is an inverse correlation between temperature and FIR frequency. Essentially, by applying less heat energy you create FIR at lower wavelengths. The FIR frequency range is approximately 5.6 microns to 1000 microns. A 9.35 Microns wavelength produces 98.6 degrees F. Heat.

Heater TypesThere are two primary types of infrared sauna heaters. These are rod and panel. Visually it is very easy to distinguish between the two. Operationally they are both very effective and similar. I’ve experienced each one, and found that they both got me to sweat profusely. They also both maintained proper cabin temperature, cost the same to operate, look good, and are safe to use.

The rod style of heater uses a coated or uncoated cylindrical material as its emitter. A rod type is significantly smaller than a panel style in area and is covered by a metal grating. The panel style of heater is constructed of a conductive fabric—commonly carbon — that is attached to a frame or laminated to a substrate. The panel type covers a larger area, is typically black, and contained in a low profile framework. The fabric can be laminated to fiberglass substrates.

Due to its large area, panel style heaters provide more uniform coverage and none of the cool spots that may sometimes be associated with rod heaters.

Parts of the heaterA heater assembly is comprised of a housing, a reflector, an emitter, and a protective cover: Housing- The frame or open case that the parts are assembled within. Reflector- A shiny metalic shield placed on the inside of the housing under the emmiter used to reflect energy into the sauna room from the back side of the emitter. Emitter - The FIR-producing conductive material. Protective cover – A metalic or wooden screen that prevents the user from coming in contact with the emitter.

Types of Materials the Emitters are Made OfThe most common types of materials that sauna heaters are constructed of are ceramic, incoloy, carbon fiber, compressed carbon, and carbon flat panel.

Each manufacturer, using what they believe to be the best material, claims to produce the heater with the optimal production of infrared heat!

Ultraviolet Light

Scientists have divided the ultraviolet part of the spectrum into three regions: the near ultraviolet, the far ultraviolet, and the extreme ultraviolet. The three regions are distinguished by how energetic the ultraviolet radiation is, and by the "wavelength" of the ultraviolet light, which is related to energy.

The near ultraviolet, abbreviated NUV, is the light closest to optical or visible light. The extreme ultraviolet, abbreviated EUV, is the ultraviolet light closest to X-rays, and is the most energetic of the three types. The far ultraviolet, abbreviated FUV, lies between the near and extreme ultraviolet regions. It is the least explored of the three regions.

Our Sun emits light at all the different wavelengths in electromagnetic spectrum, but it is ultraviolet waves that are responsible for causing our sunburns. To the left is an image of the Sun taken at an Extreme Ultraviolet wavelength - 171 Angstroms to be exact. (An Angstrom is a unit length equal to 10-10

meters.) This image was taken by a satellite named SOHO and it shows what the Sun looked like on April 24, 2000.

Though some ultraviolet waves from the Sun penetrate Earth's atmosphere, most of them are blocked from entering by various gases like Ozone. Some days, more ultraviolet waves get through our atmosphere. Scientists have developed a UV index to help people protect themselves from these harmful ultraviolet waves.

How do we "see" using Ultraviolet light?

It is good for humans that we are protected from getting too much ultraviolet radiation, but it is bad for scientists! Astronomers have to put ultraviolet telescopes on satellites to measure the ultraviolet light from stars and galaxies - and even closer things like the Sun!

There are many different satellites that help us study ultraviolet astronomy. Many of them only detect a small portion of UV light. For example, the Hubble Space Telescope observes stars and galaxies mostly in near ultraviolet light. NASA's Extreme Ultraviolet Explorer satellite is currently exploring the extreme ultraviolet universe. The International Ultraviolet Explorer (IUE) satellite has observed in the far and near ultraviolet regions for over 17 years.

What does Ultraviolet light show us?

We can study stars and galaxies by studying the UV light they give off - but did you know we can even study the Earth? Below is an unusual image - it is a picture of Earth taken from a lunar observatory! This false-color picture shows how the Earth glows in ultraviolet (UV) light.

The Far UV Camera/Spectrograph deployed and left on the Moon by the crew of Apollo 16 took this picture. The part of the Earth facing the Sun reflects much UV light. Even more interesting is the side facing away from the Sun. Here, bands of UV emission are also apparent. These bands are the result of aurora caused by charged particles given off by the Sun. They spiral towards the Earth along Earth's magnetic field lines.

Many scientists are interested in studying the invisible universe of ultraviolet light, since the hottest and the most active objects in the cosmos give off large amounts of ultraviolet energy.

The difference in how the galaxies appear is due to which type of stars shine brightest in the optical and ultraviolet wavelengths. Pictures of galaxies like the ones below show mainly clouds of gas containing newly formed stars many times more massive than the sun, which glow strongly in ultraviolet light. In contrast, visible light pictures of galaxies show mostly the yellow and red light of older stars. By comparing these types of data, astronomers can learn about the structure and evolution of galaxies.

http://science.hq.nasa.gov/kids/imagers/ems/uv.html

What is Ultraviolet Light Disinfection?

Ultraviolet disinfection is a means of killing or rendering harmless microorganisms in a dedicated environment. These microorganisms can range from bacteria and viruses to algae and protozoa. UV disinfection is used in air and water purification, sewage treatment protection of food and beverages, and many other disinfection and sterilization applications. A major advantage of UV treatment is that it is capable of disinfecting water faster than chlorine without cumbersome retention tanks and harmful chemicals. UV treatment systems are also extremely cost efficient!

Ultraviolet disinfection systems are mysterious to many people - how can "light" kill bacteria? But the truth is it can. Ultraviolet (UV) technology has been around for 50 years, and its effectiveness has been well documented both scientifically and commercially. It is nature's own disinfection/purification method. With consumers becoming more concerned about chlorine and other chemical contamination of drinking water, more dealers are prescribing the ultraviolet solution suitable for both small flow residential applications as well as large flow commercial projects.

What are the Advantages of UV Disinfection?

Following are the advantages of UV sterilization:

Environmentally friendly, no dangerous chemicals to handle or store, no problems of overdosing.   Universally accepted disinfection system for potable and non-potable water systems.   Low initial capital cost as well as reduced operating expenses when compared with similar technologies

such as ozone, chlorine, etc.   Immediate treatment process, no need for holding tanks, long retention times, etc.   Extremely economical, hundreds of gallons may be treated for each penny of operating cost.   Low power consumption.   No chemicals added to the water supply - no by-products (i.e. chlorine + organics = trihalomethanes).    Safe to use.   No removal of beneficial minerals.   No change in taste, odor, pH or conductivity nor the general chemistry of the water.   Automatic operation without special attention or measurement, operator friendly.   Simplicity and ease of maintenance, TWT Deposit Control System prevents scale formation of quartz

sleeve, annual lamp replacement, no moving parts to wear out.   No handling of toxic chemicals, no need for specialized storage requirements, no OHSA requirements.   Easy installation, only two water connections and a power connection.   More effective against viruses than chlorine.   Compatible with all other water processes (i.e., RO, filtration, ion exchange, etc.).

What are Common UV Applications?

One of the most common uses of ultraviolet sterilization is the disinfection of domestic water supplies due to contaminated wells. Coupled with appropriate pre-treatment equipment, UV provides an economical, efficient and user-friendly means of producing potable water. The following list shows a few more areas where ultraviolet technology is currently in use:

surface water, groundwater, cisterns, breweries, hospitals, restaurants, vending, cosmetics, bakeries, schools, boiler feed water, laboratories, wineries, dairies, farms, hydroponics, spas, canneries, food products, distilleries, fish hatcheries, water softeners, bottled water plants, pharmaceuticals, mortgage approvals, electronics, aquaria, boats and RV's, printing, buffer processing, petro-chemical, photography, and pre- and post-reverse osmosis.

 

How does UV Disinfection Work?

Ultraviolet is one energy region of the electromagnetic spectrum, which lies between the x-ray region and the visible region. UV itself lies in the ranges of 200 nanometers (nm) to 390 nanometers (nm). Optimum UV germicidal action occurs at 260 nm.

Since natural germicidal UV from the sun is screened out by the earth's atmosphere, we must look to alternative means of producing UV light. This is accomplished through the conversion of electrical energy in a low pressure mercury vapor "hard glass" quartz lamp. Electrons flow through the ionized mercury vapor between the electrodes of the lamp, which then creates UV light.

As UV light penetrates through the cell wall and cytoplasmic membrane, it causes a molecular rearrangement of the microorganism's DNA, which prevents it from reproducing. If the cell cannot reproduce, it is considered dead.

What Factors Affect the Effectiveness of UV Disinfection?

Because UV does not leave any measurable residual in the water it is recommended that the UV sterilizer be installed as the final step of treatment and located as close as possible to the final distribution system. Once the quality of your water source has been determined, you will need to look at things that will inhibit the UV from functioning properly (e.g., iron manganese, TDS, turbidity, and suspended solids).

Iron and manganese will cause staining on the quartz sleeve and prevent the UV energy from transmitting into the water at levels as low as 0.03 ppm of iron and 0.05 ppm of manganese. Proper pre-treatment with a sediment filter and Triangular Wave Deposit Control System is required to eliminate this staining problem.

Total Dissolved Solids (TDS) should not exceed approximately 500 ppm (about 8 grains of hardness). There are many factors that make up this equation such as the particular make-up of the dissolved solids and how fast they absorb the available UV energy. Calcium and magnesium, in high amounts, have a tendency to build up on the quartz sleeve, again impeding the UV energy from penetrating the water. A Triangular Wave Deposit Control System will handle TDS before it becomes a problem for the UV system.

Turbidity is the inability of light to travel through water. Turbidity makes water cloudy and aesthetically unpleasant. In the case of UV, levels over 1 NTU can shield microorganisms from the UV energy, making the process ineffective. Suspended Solids need to be reduced to a maximum of 5 microns in size. Larger solids have the potential of harboring or encompassing the microorganisms and preventing the necessary UV exposure. Pre-filtration is a must on all UV applications to effectively destroy microorganisms to a 99.9% kill rate.

An additional factors affecting UV is temperature. The optimal operating temperature of a UV lamp must be near 40 0C (104 0F). UV levels fluctuate with temperature levels. Typically a quartz sleeve is installed to buffer direct lamp-water contact thereby reducing any temperature fluctuations.

The Skin Cancer Foundation Dispels Common Tanning Excuses

Winter Indoor Tanners Beware:Just Four Annual Visits to an Indoor Tanning Salon Significantly Increases Skin Cancer Risk

November 21, 2011 (New York, NY) – Nearly 30 million Americans who visit tanning salons each year may do so because they believe they look better with a tan. In fact, they are putting themselves at risk for skin cancer and premature skin aging. Ultraviolet (UV) radiation is a proven human carcinogen, and is linked with a higher risk of all forms of skin cancer, including potentially deadly melanoma, the most common form of cancer among young adults ages 25-29 years old.

Multiple reports have documented the health risks associated with using UV-emitting tanning devices. With the help of this research, The Skin Cancer Foundation is dispelling some common tanning excuses.

“I only use tanning beds once in a while”You don’t need to be a frequent tanner to increase your risk for skin cancer. While it is true that melanoma risk increases by 74 percent for frequent tanners, new research finds that those who make just four visits to a tanning booth per year increase their risk for melanoma by 11 percent, and their risk for the two most common forms of skin cancer, basal cell carcinoma (BCC) and squamous cell carcinoma (SCC), by 15 percent.

“I’ll stop tanning eventually”Research has shown that tanning is addictive. Exposure to UV radiation from tanning machines stimulates the “rewards center” in the brains of frequent UV tanners, which could cause tanning addiction, according to a new study in Addiction Biology. When activated, the rewards center releases feel-good chemicals, which “could reinforce the tanning behavior, encouraging excessive tanning,” said Heidi T. Jacobe, MD, study coauthor and Assistant Professor of Dermatology at the University of Texas Southwestern Medical Center at Dallas.

“Tanning beds are safer than being in the sun”Tanning salon owners say tanning machines are safer than outdoor tanning for two reasons: 1) they mainly emit ultraviolet A (UVA) radiation (vs. the ultraviolet B rays that cause sunburn), and 2) they offer more "controlled" UV exposure. However, we now know that UVA, like UVB, is a carcinogen, and studies have revealed that tanning salons often exceed "safe" UV limits. Frequent tanners using new, high-pressure sunlamps may receive as much as 12 times the annual UVA radiation dose compared to what they receive from sun exposure.

UV radiation, either from the sun or a tanning machine, causes skin damage that is cumulative and often irreversible. The destructive process of photoaging – premature skin aging due to UV exposure – produces profound structural changes in the skin including wrinkles, blotchiness, sagging and a leathery

texture. Some of these changes may appear as early as the age of 20 in anyone who has spent a great deal of time exposing their skin to UV radiation during childhood and teen years.

The Skin Cancer Foundation aims to remind and inform consumers that, aside from sunless tanning products, there is no such thing as a safe tan. In addition to avoiding tanning beds, everyone should protect themselves from the sun by covering up with clothing, seeking the shade and using sunscreen. For more information and a complete list of sun safety tips, please visit www.SkinCancer.org.

Editor’s Note: The Skin Cancer Foundation has many experts available to comment on indoor tanning issues. Additionally, the Foundation has access to individuals willing to share their personal experiences with indoor tanning and skin cancer.

http://www.wilsoncountynews.com/article.php?id=39526&n=consumer-updates-the-skin-cancer-foundation-dispels-common-tanning-excuses

X-Ray Discovery Sparked 19th-Century DIY Craze

What are the social consequences when science allows us to see things that had previously been invisible?

Scientists have revealed microscopic life, nanoscale molecules and galaxies billions of light years away. These images have revolutionized the disciplines in which they were made, but they also transformed the public’s imagination, letting them see new things to think and dream about.

The intertwined social, scientific and artistic impacts of 19th century photography is the subject of a new exhibit, Brought to Light Photography and the Invisible, 1840-1900, at San Francisco’s Museum of Modern Art.

In this five-part series, we walk through the exhibit with its curator, Corey Keller. Keller spent five years scouring dusty archives, primarily in Europe, to dig up dozens of haunting photographs from the period. Many of the images have never been seen, except by their creators. Up first is the X-ray, which allowed us to see through our skin and muscle to the bones that lay within.

 

In 1895, Wilhelm Conrad Roentgen discovered the X-ray, a form of electromagnetic radiation with a very short wavelength.

Waves that are shorter can penetrate denser materials. X-rays are perfectly tuned to barrel through soft tissues like muscle and fat, but get slowed down by denser materials like bone. That allowed early scientific photographers — and your dentist — to employ these rays to see skeletons without cutting into flesh.

To the common people at the time, this was (and probably should remain) astonishing. Within three months, Keller said, DIY X-ray kits were available on the market. The rich and famous had their hands X-rayed, their skeletons draped in rings. Photographers, who had access to most of the tools needed to make the images, began to train this new form of light on just about anything that might be beautiful. 

"They were X-raying everything just to see what it looked like," Keller said.

In this series of images, we see the strange hodgepodge of subjects that early X-rayers tackled. At the top of the post is a chameleon, and further down the page, the boot of a shoemaker who built his own x-ray machine for fun. Below, you’ll find a river dolphin fetus, two fish and the hand of the wife of Nicholas II, the last czar of Russia.

http://www.wired.com/wiredscience/2008/11/xrays/

Body scanners in use at airport

It's just like going through a metal detector. Only when an airline passenger goes through the newly installed full-body scanners, security personnel may pick up more than loose change.

The Transportation Security Administration rolled out two new body scanners at the A.B. Won Pat Guam International Airport yesterday, adding Guam to the list of approximately 550 U.S. airports using Advanced Imaging Technology machines.

At the departures gate two blue frames, slightly more ostentatious than a regular metal detector, have been added to the maze of security procedures passengers must undergo before getting on an airplane.

The scanners use backscatter technology that projects low level X-ray beams over the body to pick up metal and non-metal objects. The scan creates a reflection of the body, which is displayed on a monitor at a different location.

A few feet away, in a walled-off area at the terminal, two screens show the images of passengers as they walk through each scanner. The images are rough outlines, and do not show specific features of those going through the machines. The images are not stored, and devices with recording capability are strictly banned, Brian Cahill, federal security director of the U.S. Department of Homeland Security Transportation Security Administration, said.

Even if something irregular shows up on a passenger's body, the image will not be stored. Passengers who are identified as having an anomaly on their scans will be searched further by an officer to identify the object.

The addition of the machines, which cost between $130,000 to $170,000 to purchase, deliver and install, was federally funded, Cahill said.

The scanners are optional, but if passengers decide not to use the machines they must undergo a pat-down. Nationally about 2 percent of passengers opt out of the scanners, Cahill said. As of yesterday afternoon, two passengers had declined to use the scanner.

Cahill said the scanners will only take about 20 seconds for passengers. And they may speed up the process for some. Because the low level X-ray beams do not penetrate the skin, scanners won't pick up artificial body parts and other implants that often cause problems for disabled passengers, he said.

The TSA began using the scanning machines in 2007. While the machines now are in widespread use at more than 100 airports in the U.S., concerns over the safety of the scanners have persisted.

The European Union recently adopted a legal framework for the use of scanners, which requires airports to comply with a strict set of standards, according to the European Union website. The European Union banned scanners that use X-rays from its airports, which would include backscatter machines.

The machines have been in use since midnight Sunday morning, and Cahill said passengers haven't complained.

"We're getting very positive responses. Or should I say neutral to positive responses? We're not getting any negative responses at all," Cahill said.

http://www.guampdn.com/article/20111213/NEWS01/112130310

X-Ray Vision Gives Great View of Black HolesIt's known as Arp 147 — object number 147 in astrophysicist Halton Arp's Atlas of Peculiar Galaxies. For years, astronomers have known that it's really two galaxies that smashed through each other millions of years ago.

The collision didn't destroy either of the massive star clusters, but it did send massive shock waves rocketing outward in both, compressing sparse interstellar gas at their leading edges. That caused the galaxies to burst into light as rings of newly formed stars, spanning tens of thousands of light-years. (See Hubble's recent discovery of ancient galaxies.)

The pair looks spectacular enough — especially the right-hand galaxy — when photographed in ordinary light. But the cosmos glows with kinds of light our eyes can't see, all the way from radio waves up through infrared, ultraviolet and X-rays.

And when you look at Arp 147 with X-ray vision, as the orbiting Chandra X-Ray Observatory can, something else appears: the telltale glow of black holes, studded around the circle of stars like diamonds on a ring. (In this picture, a composite of Hubble and Chandra images superimposed, they show up in pink.) The black holes come from massive stars created by the shock wave, which have already sped through their life cycles and collapsed into the universe's ultimate vacuum cleaners. Black holes being black, it isn't the objects themselves that astronomers see; instead, it's surrounding gases being sucked into the holes, heated up to millions of degrees as they go.

All of that cosmic violence seems comfortably far away: Arp 147 is about 430 million light-years from Earth (that's 2 billion trillion miles, give or take), in the constellation Cetus. But we're not as safe as we think. The Milky Way is currently on a slow collision course with Andromeda, the spiral galaxy that sits practically next door in astronomical terms. In five billion years or so, the two will probably collide — and when that happens, our home galaxy could go through some wrenching changes of its own.

http://www.time.com/time/health/article/0,8599,2048720,00.html