image via: lydurs

What is It?

In California it is 5% of our overall energy, in El Salvador it is 25% of their energy use. Idaho and Iceland use it to heat their buildings and keep homes cool or warm. Geothermal energy is gathered from underground, about 33,000 feet underground and has 50,000 times more energy then our natural gasses. But we don't have to go 33,000 feet underground to get this energy. In hotspots the earth's crust is thin enough to let heat out. Most of the midwest, and especially Nevada is filled with hotspots. Also, most of Louisiana and Southeast Texas.

How do we get it?

There are three forms of geothermal plants, dry steam, flash steam, and the binary cycle plant. In genereal these plants use the natural process of "hydrothermal convection" to capture the steam. Hydrothermal convection is when the cooler water gets soaked into the earth and than rises back up in a much hotter temperature. These plants drill holes into the existing hot rock surrounding the area in order to capture it. So, what is the difference between the three and which one do we know is to be used? In dry steam poweplant, the original and most commonly used plants the steam goes into a turbine, this allows the turbine to run off the steam and not any fossil fuels. The steam is gathered through a drill, into the turbine, then into a generator. The largest plant of geothermal energy uses this process, in our own state it is called The Geysers in Northern California. But this process disperses a lot of steam into the air, as well with some air pollutants.

The second form used is the Flash Steam Power Plants, this system uses the hydrothermal fluids. These fluids are rushed into a tank called the flash tank, the tank is at a lower pressure so this causes some of the fluids to immediately flash into vapor then run through a turbine and goes through the same process as the previous plant, but with this plant you can add another flash tank and gather even more energy.

The most modern of them all is the Binary Cycle Power Plants, this is a closed system so almost nothing goes into the earth's atmosphere! Hydrothermal fluids and moderate fluids with lower boiling points are gathered through the drill, then they are passed to the heat exchanger, the hotter fluids cause the more moderate fluids to vapor or flash. Then the rest goes into the turbines, and then the generators.

In an area that may not provide as many hydrothermal fluids, the binary cycle power plant would be ideal since it can combine the two.

If this became a major energy source that would most likely be the most common, it emits no pollutants and doesn't have to be in only an intense hot spot. The resources of geothermal energy are basically endless, it comes from hot water resevoirs, the magma, and hot dry rock. The heat from our earth's crust will always be there so it would be ideal to run off this alternative and stop the fossil fuels. As long as we accept and produce the technology to gather this energy then this can become a very important source of our energy and wouldn't just take up 5% of California's energy, but increase and help our whole nation.

Solar Energy

image via: rob

How does it work?

We all know what solar energy is, but how do we get it to light up our homes and run our electronics? You would think with all the sunlight in the world all of us would be living off the sun's energy. The sunlight in twenty days can match all the energy reserves we have here on earth. A somewhat obvious was to light up our homes is by simple desgin, clear windows up top can light a whole living room. I recall living in an apartment that had these skylights and we never had to use a light, until nigh time of course. I think this would be ideal for offices and would really cut down electricity, seeing as offices are most only used till the late afternoon. But then there is the more expensive, but only one time expense for your home. Solar panels or Solar Heat Collectors, these are the most common we see on rooftops and such. But these can only power cooling systems, an example of this system would be desiccant evaporators. The hot air is seprated from the cooler air, and the hot air is realeased. Another process to power our air conditioners, even refrigerators is an absorption chiller.

Photovolatics

This was discovered in 1839 by a French scientist, he discovered that certain materials when struck by light caused a spark of electricity. By the 1950's this theory was put to the test and ended up powering many satelites! It is basically two layers of silicon, but with additives. The bottom layer with a boron addition and the top layer with phosphorus. These two make two opposite charges, like a battery! With a circuit and sun light the electricity can be carried through the circuit give the owner of this cell its own electricity!

In the Future

Many states, specifically California have come to realize the importance of this renewable energy. In 2006 the California Solar Initiative was approved which dedicated billions to solar research and provides over a million homes with solar panels on their roofs! Many states promote this with tax incentives and even the federal government has been said to pay up to thirty percent tax credits for the purchase and installation! The only problem is, it is an expensive buy and installation, but it is only at one time. It reduces your monthly bills, and proves a huge savings by the end of the year.

Wind Energy

image via: pbo31

How does wind turn into electricity?

When I was young and driving up to San Francisco I remember seeing thousands of windmills and I didn't understand why, when I asked my parents what it was for they said electricity. I simply couldn't understand how that windmill could light up a home. Wind electricity prices have dropped very much over the years about 4-6 cents per kWh now a days, but these wind turbines have risen in price. These wind turbines are those simple windmills you see on the way to San Francisco, but behind the simplicity a lot is at work. For AC electricity it is somewhat simple, but for electricity elsewhere, the wind has to be at a certain rate in order to achieve electricity. Since winds change, so does the gearbox behind the blades inside the "tower" the blades are connected to. It is suggested to use a gearbox that varies because a slow one can come to a stand still during slow winds, and a fast one could alter equipment. You cannot just get any windmill but a specific wind turbine, the blades are especially made to capture the winds kinetic energy. For these wind turbines, placement is everything, putting it in a place with no wind would make it virtually useless.

Overall, all of three of these alternatives would be fantastic for our nation. Sadly all three of these are in the other category, and in totaly only 5% of our nations energy is used through these alternatives. All these of these alternatives have endless resources, but not everyone can pay that big lump sum at the time to get this technology even with tax incentives. In order for us to stop depending on coal which is 52% of our nation's energy use we would have to make this technology more affordable and available. Once that happens we can easily use all these abundant resources!

How it works: The concept is about a satellite built into the High Earth Orbit that uses microwave power transmission to beam solar power to a very large antenna on Earth.

Advantages: The satellite will have access to the sun all the time, 24/7.

Disadvantages: It is very costly. The only way to eliminate this is to find reusable materials on Earth which could be used for building the satellite. NASA and other agencies around the world have worked together and still need to come to a conclusion if this is a potential powerful source that could someday even replace nuclear power.

4. Geothermal power

How it works: This is one of the best nuclear power alternatives currently available. Geothermal power is basically an energy generated by heat stored in the earth, or the collection of absorbed heat derived from underground, in the atmosphere and oceans.

Advantages: It requires no purchase of fuel. The energy is stored in the earth. Also, there's very little emissions. That means from ecological point of view, geothermal power is a lot better than the current, nuclear power.

Disadvantages: There are several disadvantages of geothermal energy. One of the biggest concerns is that some specific locations i.e. sources of geothermal power may cool down over time resulting in depletion.

3. Wind power

How it works: I'm sure you have already heard about wind energy and its potential. Large wind farms are connected to electrical grids thus producing electrical energy that can be used for different purposes.

Advantages: Wind power is easily renewable and cannot be easily diminished. Many countries started using it widely. In Denmark, 19% of electricity usage is from wind energy. In Spain in Portugal, the percentage is 9% while Germany accounts for 6% usage.

Disadvantages: Animal impact. Wind turbines have a negative impact on birds, which can be killed or injured through collision with the rotating blades especially while seasonal bird migration. To reduce this impact, most wind turbines are built outside of bird migration corridors.

2. Solar Power

How it works: See those objects above? They basically "steal" sun's energy which later converts into electrical power. Solar energy is becoming one of the dominant alternative sources of energy lately.

Advantages: The sun is unlikely to stop emitting energy soon. New dish engine systems like the one above are built every day all around the world. We should expect even bigger expansion of this type of renewable energy in the future.

Disadvantages: The systems are very costly to built. Also, they are useful only when the sun is shining. In the night, they are practically useless. Lately the effects of this disadvantage are reduced by the use of solar battery chargers.

1. Biomass

How it works: Dead biological material can be used as fuel or for industrial production. Also, biomass can refer to plant matter grown to generate electricity or produce biofuel.

Advantages: The industrial type of biomass can be grown from numerous types of plants and trees. This number of plants increases ever day so you can suppose that biomass as renewable source of energy and its usage will continue to grow in the future.

Disadvantages: Biomass is part of the carbon cycle. That means that using biomass methods produce a large portion of Carbon Dioxide or CO2. You can suppose that biomass is one of the many factors that contribute to the global warming.

Do you think there's another alternative source of energy that's worth mentioning but is not mentioned here? If you do, feel free to comment in the comments section below.

However, now; in the year 2008 we are perhaps the closest we have ever been to realising, if not true immortality, life extension the likes of which have never before been possible. While there are numerous moral, social and economical arguments about life extension, none will be discussed in this article. What I will list in this article are five of the most probable advances in technology which offer us vastly extended, or even eternal lives (of a sort).

Cybernetic Immortality or 'Mind Uploading'

The practice of 'scanning' a human brain and recording its state at a given time onto a non-biological substrate is a concept that has been explored by many science fiction writers (notably William Gibson, Peter Hamilton and Ian M. Banks). Whilst this process might arguably fail to preserve a person's consciousness or 'soul', the concept of being able to store a copy of your brain to 'download' a new version of yourself could be considered a form of immortality.

While this process is not yet possible, scientists are continually making progress in the study of the human brain, and the production of computers that work more and more like their biological counterparts. Advances in our understanding of how signals travel and originate in the brain, how data is stored and organised as memories and novel methods of scanning human tissue are all making the possibility of creating a hard copy of someone's consciousness and memories seem more and more real.

Chips have been made which can interface with the brain, or mimic parts of it; neuroscientist Ted Berger of the University of Southern California has produced a microchip (about a millimetre squared in size) which can translate signals from a rat's brain into code it understands, and send signals back in a format the brain can use.

Whilst hardware like this has a long way to go, as does the understanding required to program these signals into useful forms, the progress is tantalizing. Berger predicts that the first human trials of this chip in treating Alzheimer's patients are no more than 15 years away, which means that the first working brain implants could be coming within our lifetimes; indeed, if progress continues at this rate, a full copy of the brain might not be too fantastical an idea after all.

But whilst we're busy replicating the brain, why stop there? Replacement eyes, ears, arms, legs and many other organs are in production as we speak. Artificial hearts are making great progress and an artificial bladder has been produced for the first time ever. This opens up the road for humans to gradually replace parts of themselves as they 'break down', effectively maintaining themselves as one would a car, or even upgrading parts as with a home pc. Nevertheless, the question remains; where does our humanity end? What do we become when we are more machine than man, and if we were to ultimately replace all our parts with superior artificial ones, could we still be considered human?

DNA Therapy and Genetic Engineering

If the body is a machine, DNA is both the schematic and the programming. Every aspect of our lives, from our weight to our happiness, our height, looks, strengths or weaknesses and even personalities are in some way influenced by our DNA. If we could change this schematic, rewrite the code, the possibility of extending and improving our capacity for life would be almost endless.

And science is gradually achieving just that ability. Already the human genome has been sequenced, and over 100 Gigabases (100,000,000,000 bases; the 'letters' of the genetic code) from various species including us have been documented and stored. Whilst we don't yet know the specific function of most of these genes, they are gradually revealing their purposes to us.

Genes have been found which relate to weight gain or loss, inherited disease, physical characteristics, sexual orientation and even ageing. With this knowledge, scans of people's genome could be made which allow personalised medical treatment and diets, and could explain many ailments for which we as of yet have no cure. Changes could be made to the genes which regulate our appetites to discourage overeating, and genes linked to ageing could be modified or replaced to allow us to live longer and repair ourselves more effectively. Genes from other species could be used in our bodies to code for desirable characteristics, and potentially damaging genes which code for inherited disease or malformation can be removed and repaired in the foetus.

Whilst this is all well and good, we've got a long way to go before any of this becomes a reality. Research is going on regarding the changing of an adult's DNA (gene therapy), but progress is slow, whilst the editing of babies' genes, producing 'designer babies' evokes a huge amount of controversy.

Nevertheless, progress is being made, and with every step forwards we come closer to the dream of being able to edit our bodies how we wish to suit our lifestyles and increase longevity. Viruses are being experimented with in the field of gene therapy, where they infect a body and insert or remove genes, and new genes coding for different characteristics are being found every day.

Stem Cell Research

The cells that make up our body invariably age, and die, and are replaced, until old age reduces our ability to replace dead cells to the extent that we cannot keep going, and our life ends.

But what if we could boost that repair system?

Stem cells are a type of cell found in both embryos and adults (though in differing forms). These cells are capable of renewing themselves via mitosis, and can differentiate into a wide range of mature cells, thereby allowing a foetus to develop, and an adult body to repair itself easily.

So what if these cells could be collected or even produced artificially, given to people whose own repair systems need a boost, and stimulated to grow into the cells the patient needs? Ageing could effectively be halted, as organs would not deteriorate and any dead cells could be replaced with fresh ones. Alternatively, these cells could be used to produce entire organs outside of the body, and these could be transplanted as and when a given organ fails. A form of stem cell therapy already exists for some conditions, notably bone marrow transplants for leukaemia patients (allowing the patients to produce new blood cells and immune cells over a long term when their own natural ability to do so has been damaged).

Whilst research into stem cells looks promising, controversy in the field has slowed progress dramatically, both in terms of production and use of the cells. Cells harvested from foetuses are argued to be morally wrong, and opponents of the research argue that embryonic stem cell technologies are a slippery slope to reproductive cloning and could devalue human life. Faked research has been published about the topic, particularly from Korean researcher Hwang Woo-Suk, who announced that he had produced embryonic stem cell lines from unfertilised human eggs; the lines were later shown to be fake.

The possibility of manipulating adult stem cells to act like their embryonic counterparts has, in principle, been demonstrated, but not enough progress has been made to remove the controversy surrounding usage of embryonic cells.

If stem cell research continues, tissue regeneration and age-prevention therapies look to be at least partly possible within our lifetimes.

Cryonics

Cryonics (not to be confused with cryogenics) is the low-temperature preservation of humans and other animals which current medicine cannot sustain, in the hopes that future techniques can be used to repair them.

This method of 'life extension' is already legal and practised in many places in the world (for example, in the USA, where the patient has to be legally deceased and the heart demonstrated to have stopped before preservation is permitted). The patient is pumped full of chemicals called 'cryoprotectants' which prevent damage from ice crystals and the preservation process, and then is cooled to around 77K (-196°C), preserving the body in the state it was in at the time of 'death'.

Whilst dead in legal and conventional terms, and current cryopreservation methods are irreversible with current technology, the hope is that the patient can be resuscitated at some future point, and any damage from either the cause of death or the preservation process itself can be repaired.

Whilst cryopreservation offers an extension to life by making future technologies potentially accessible to the patient, it in itself does not extend life, rather it preserves the body as well as possible at the point of death.

Calorie Restriction

The lowering of energy intake, or calories, when practised in an otherwise healthy diet, has been demonstrated in laboratory experiments to extend the maximum lifespan of almost every species tested so far, including rats, yeast, fruit flies, and nematodes.

In rats, a roughly 50% decrease in calorie intake compared to an animal that freely fed led to an extension of lifespan by the same amount. Experiments on calorie restriction are now being carried out on primates, to see if the same will work with humans, and many scientists are confident that similar results will be seen.

Whilst the other technologies mentioned in this article are not yet scientifically possible, calorie restriction is possible now, for anyone who decides to practice it, and the potential benefits are massive,

Nevertheless, a high level of scepticism exists in the scientific community about the practice, as some scientists suggest that the practice only works in short-lived species which have evolved to respond to feast and famine with alterations in longevity.

Proving that the practice is generally applicable to most species is a challenge, but the results will certainly be seen far before any of the other technologies in this article. Along with calorie restriction, a healthy diet with the right levels of nutrients is perhaps the best form of life extension we have available at this point in time. Whilst this might sound trivial, it is only because of advances in nutritional science that we know what a 'good diet' is, and more progress is expected even here.

Most robots are made up of five major components like human beings and animals.

• A body structure
• A muscle system to move the body structure
• A sensory system that receives information about the body and the surrounding environment
• A power source to activate the muscles and sensors
• A brain system that processes sensory information and tells the muscles what to do

But of course human beings have some intangible attributes, such as intelligence and morality. But on the sheer physical level, robots and human beings or animals are likely the same. Robots even replicated human and animal behaviours.

But to consider the name “Robots,” which comes from the Czech word robota, meaning “forced labour.” They sometimes live up that way as define above, a “benevolent partners or helpmates.” Imagine a worker who is always on the job, who never complains, and who can work tirelessly 24 hours a day, seven days a week. Well, industrial robots are doing just that as they a host of automotive, electrical, and household items. And now, they even come equipped with such things: voice-recognition software, gyroscopes, wireless data communication, Global Positioning Systems, and a range of sensors including those for heat, force, ultrasound, chemicals, and radiation. More powerful and versatile than ever, performing complicated tasks in helping human activities.

The procedure involves bending light around three dimensional objects. In the past, it has been possible to cloak (bend light around) two dimensional, thin objects. With the new technology, larger objects can be made easier to hide from view.

The reason we can see objects now is that the objects tend to scatter the light which strikes them, causing some of the light to reflect back to the eye. This new cloaking concept is similar to water flowing around a rock in a moving stream. The light waves as well as radar waves tend to go around the object rather than reflecting it.

The materials used in this procedure are referred to as metamaterials and include Teflon, ceramic and fiber composite. These metamaterials mixtures are designed to bend the light around objects and not create shadows or create reflections.

This concept, in some ways, resembles stealth technology although it does more than reducing its ability to be traced by radar. It actually makes light go around objects so they cannot be seen at all.

1. Make a Non-Newtonian Fluid with Cornstarch and Water

   Basically, when you apply pressure to the non-Newtonian fluid it turns to a solid, otherwise it's a liquid. So basically if you were to fill a pool with the stuff you could run across it, but if you stopped running and just stood there you would sink. Here's a guide if you'd like to try it out. Check it out:
   
   

2. Make a Laser Pointer that Can Burn Things

   You'll need to have some equipment to solder and buy a 16x DVD Burner to do it, but it'd definitely worth it! Here's a video to show you how:
   
   

3. Make an Electric Multi-Touch Whiteboard with a Wii Remote Control.

   This is probably one of the coolest things I've seen; all you need is a Wii remote control and a projector to make this work. It's a cheap project for what you get in return. It's possible to do on Linux, Mac OS X and Windows XP as well. Go here for a guide on how to do it. To see how cool it is, just check out the video below!
   
   

4. Play with Dry Ice

   Dry ice is definitely a cool thing to play with, especially if you have some apples, flowers and things like that. All you need is the dry ice and some stuff to freeze with it. Look how much fun these girls had with it:
   
   

5. Get some Raw Sodium and Put it in Water

   This is probably the most dangerous one, depending on what you do. When you put raw sodium in water an extremely violent reaction occurs causing the sodium to catch on fire or explode. It doesn't take much sodium to cause an explosion, so be careful! Even a quarter-sized chunk could potentially be very dangerous. These guys show you just how dangerous (and fun) it really is:
   
   

Hopefully one day when you're bored you can come back and try one of these; I guarantee you'd be in for some fun and excitement!

UFOs, or unidentified flying objects, have been observed for most of the existence of Western civilization. But these observed objects may not be as foreign as previously assumed. Patents from the US patent office and other nations throughout the world show that people have at least been attempting to build craft that match the descritption of these so-called "flying saucers."

Patent number 3,774,865, published in 1973, describes a saucer shaped craft that could be used as a passenger craft or even as a toy capable of moving at high velocities and of taking off and landing in a vertical manner.

The Avro Car was developed somewhat along these lines except that it utilized a ducted fan to achieve its lift. It could never get out of its own ground effect (whereby the air pushed down creates a cushion below the craft that it sits on) and the research project was discontinued.

While the above patent utilizes known technology the craft would still have the appearance and maneuverability of that ascribed to UFOs. However, there is more than just a single patent utilizing known technology. There are patents for things like plasma propulsion and magnetohydrodynamic propulsion. It operates by sending high frequency, high voltage elctricity from the top of the craft to the sides or the bottom of the craft. This approach was utilized in Nazi saucers during WWII.

A craft that crashed in White Sands, NM in 1996 appears to utilze the other of the two mentioned technologies; that is plasma propulsion. Plasma propulsion creates an envelope of plasma around the vehicle allowing the vehicle to not only soak in all incoming signals (making it invisible to radar) and to move at unprecidented speeds. A patent published in 1955 boasted 60 times more power than present day rockets.

One thing must be considered and that is the two ways a patent can be validated. The first is with a working model and the second is it is logically provable using main-stream science. The technology powering the craft that are seen doing amazing things has been patented and is mostly within the public domain now. The craft exist and the technology does as well. It is only a matter of time before it is utilized and mankind moves into the space-age.

Cleaner Environment

The argument has been made that solar power produces little to no pollution, and there is no doubt that this is true. Will solar power completely reduce greenhouse admissions? Probably not. We will still need other energy sources for the foreseeable future. However, solar energy will definitely make a big difference.

Less Blackouts

When you think of solar power, you probably think of thousands of solar panels sitting in a desert somewhere. However, that's only one way to utilize solar power. Think about this. What if every house, apartment complex, condominium; etc had a solar panel on their roof that powered that entire structure? And imagine if the solar panels were all linked together.

Instead of having one specific area where our power came from, we would have power coming from all directions. If the solar panels on your roof were to fail, then excess energy from your neighbors roof would take over for you. And so on. You wouldn't even have to be without power. Is this science fiction? It really isn't. It's just a new way of thinking.

Some companies are even trying to create a translucent liquid that could be combined with your windows, and this liquid would provide energy in the same way that solar panels currently do. Imagine the possibilities. Our future could become very interesting. And did I mention that you can profit from this?

Make Money

How in the world do you make money from solar energy, you're probably saying to yourself. Well, it's simple really. If you have solar energy powering your home, then you can sell any excess energy that your solar panels produce to your local energy company. So you've just turned your home into a pollution free power plant.

Problems

Unfortunately, solar panels can be really expensive. Currently, the solar panels that can power an entire home cost between twenty and thirty-thousand dollars. This puts this type of energy outside the reach of many individuals. Fortunately, in five to ten years, it should become cheaper to manufacture these types of solar panels. Until then, you'll have to pay a lot of money to use them. But one day, everybody may be using them.

Other Info

Just so you know, solar panels that are used to power homes currently last about twenty to thirty years. Many of these solar panels can withstand hail that is an inch in diameter, and high winds that are up to one hundred fifty miles per hour. They also add value to your home.

Solar energy could open up new avenues in both profit and environmental conservation. No longer will you have to pay your local energy company to provide you with power. In fact, they may pay you.

Fiber Optic Lines

A fiber optic cable is comprised of varying numbers of bundled fiber optic lines (see Figure 1). Each fiber optic line has a core made of an incredibly thin long strand of optically pure glass or plastic capable of carrying digital information over very long distances through the propagation of light carrying signals. The key components of a fiber optic line include:

• Inner Core - The inner core is usually made of very long strands of optically pure glass or plastic. This is where the light travels
• Outer Insulating Jacket - Usually made of Teflon or PVC and helps to protect the other layers from mechanical damage and moisture
• Kevlar Fibers - Helps to strengthen the cable and prevent breakage
• Plastic Coating - Cushions the fiber core against shock damage as well as adding waterproofing functionality
• Optical Cladding Layer - Surrounds each individual glass or plastic strand. Without this cladding the propagation of the light signals down the length of the fiber cannot occur. This is the solid blue/gray layer in Figure 1 and that to which the arrow labeled “Cladding” is pointing at in Figure 2.

Fiber Optic Cables

Hundreds and sometimes even thousands of these individual fiber optic lines are bundled together to form a fiber optic cable. A protective jacket then encases (an additional outer covering) the bundles of fiber optic lines to form what we know as a fiber optic cable. The jacket also serves to keep all of the constituent fiber optic lines together in a neater more easily managed package.

Types of Optic Fibers

Optic fibers commonly come in one of two forms:

1. Single-Mode Fibers - These fibers have small cores that are about 9 microns in diameter and transmit infrared laser light (wavelength = 1,300 to 1,550 nanometers). Communications links greater than 200m are one of the major uses of single-mode optic fiber cables. 
2. Multi-Mode Fibers - Multi-Mode fibers have larger cores than single-mode fibers that are about 62.5 microns in diameter and transmit infrared light (wavelength = 850 to 1,300 nm) from Light-Emitting Diodes (LED). They also support multiple transmission paths hence their name multi-mode fibers. Their main applications are for communications over short distances or for applications requiring high power transmissions.

Fiber Optic Cable Connectors

While there are a number (20+) of different types of fiber optic connectors on the market, the majority of connections have predominantly used either one of two types.

Note also that many of the various connectors are technology or proprietary specific and are incompatible with other systems. For example, Fiber Distributed Data Interface (FDDI) has its own specific connector, as does Toshiba's fiber optic digital audio (TOSLINK connector) which is shown in Figure 3.

The primary roles played by these fiber optic connectors are to terminate the ends of an optical fiber and mechanically couple (join) and align the cores of the fibers in order to facilitate the passage of light (the signal). They also provide a connectivity system that is far easier and quicker to implement than splicing allows.

The main differences between the various types of optic fiber cable connectors are their physical dimensions and methods of coupling. Because of this, most organizations will elect to use one type of connector on an organization-wide basis for all of their fiber optic connectivity requirements.

Whenever it is not possible to do so then it makes sense to select a standard alternative connector for specific connections and the primary connector for the rest. A common scenario in which the need to use different connector types based on the type of cable in question arises when using both single-mode and multi-mode fiber optic cables within the same production environment implementation.

The two predominant fiber optic cable connectors are:

1. ST Connector - Traditionally, the barrel shaped (similar to a BNC connector) ST connector (Fig.4) has been the most commonly used type of optic fiber cable connector
2. SC Connector - The newer square faced SC connector (Fig.5) is rapidly becoming the optic fiber cable connector of choice, as it is considerably easier to install (particularly in confined spaces)

Fiber Optic Cable - Signal Propagation

The optical cladding used in fiber optic cable construction is an overlooked (not glamorous) yet key factor in this technology. To understand how it works we need to explore a little bit into the world of radiation physics.

In order to ease the pain somewhat I will keep it simple and tell this tale in pictures but first we need to clarify precisely what it is that we are referring to when we are using the terms “critical angel” and “total internal reflection”. Yes, this is crucial if we are to understanding the propagation of signal down a fiber optic cable.

Critical Angle - In physics, we describe the critical angle with respect to the normal line. In fiber optics however, we describe the critical angle with respect to the parallel axis running down the middle of the fiber. It therefore follows that the Fiber-Optic Critical Angle = (90 degrees - physics critical angle). Figure 6 illustrates this.

Total Internal Reflection - Now we can move onto clarifying the concept of total internal reflection. The first point that we need to understand here is that whenever light passes from one medium with a high index of refraction into another medium with a lower index of refraction, it bends. Figure 6 shows this.

As the angle of incidence of the light travelling through the first medium increases so does the degree to which it bends. If you progressively increase the light's angle of incidence, you will eventually reach a point (angle of incidence) where the light will no longer pass into the second medium. Any further increase in the angle of incidence results in the complete reflection of the light back into its current medium (see Figure 6).

This phenomenon is what we call total internal reflection (see Fig.6). To put it another way, we have used the laws of physics to trap or confine the light to the core of the fiber optic fiber (line). The fiber optic fiber is therefore acting as a waveguide.

Fiber Optic Cable and Total Internal Reflection - Now let us look at how this relates to signal propagation using fiber optic cable as the transmission medium.

In an optical fiber, the core has the higher index of refraction relative to the cladding, which has the lower index of refraction. Whenever the light signal attempts to pass from one medium (the core) into the other (the cladding), the difference in the refractory indexes of both media comes into play.

Because the angle of incidence is always greater than the critical angle and the cladding does not absorb any of the light, the light bounces off (reflected) the cladding all the way down the fiber's length. The net result is that the light signal will be propagated down the length of the fiber regardless of any bends; even a complete circle, in the cable. Transmission over very great distances is thus possible.

Acceptance Cone- Only light that enters the fiber within a certain range of angles can be successfully propagated the length of the fiber without leaking out. We call this range of angles the acceptance cone of the fiber (see Figure 8) and its size is a function of the refractive index difference between the fiber's core and the optic cladding.

Numerical Aperture (NA) - There is a maximum angle at which light can enter the fiber and be successfully propagated the entire length of the fiber. We refer to the sine of this angle as the Numerical Aperture (NA) of the fiber.

The importance of the NA lies in the fact that larger the NA the less precision required in splicing the fiber compared to a smaller NA. This translates into technologies based on fibers with a larger NA being easier to manufacture, implement, maintain and repair if need be.

Signal Degradation - Unfortunately, some of the light signal does degrade within the fiber, mostly due to impurities in the glass. The extent to which the signal degrades depends on the purity of the glass and the wavelength of the transmitted light.

For example, light with a wavelength of 850 nm suffers 60 to 75 percent degradation per kilometer, 1,300 nm light signals experience 50% to 60% degradation/km and at a wavelength of 1,550 nm the degradation is greater than 50 percent/km).

Some premium optical fibers made of particularly optically pure glass exhibit much less signal degradation, which in some cases can be less than 10%/km at 1,550 nm.

Optical Regenerators - Optical regenerators installed into the fiber optic cable at various points serve to overcome signal degradation issues.

Because the optical regenerators require splicing into the cable, implementations such as long haul deep-sea rollout scenarios necessitate that the insertion of the optical signal regenerators must be performed either; prior to loading the cable onto the deployment ship or to perform the splicing operation on-board the deployment vessel “on-the-fly”. For smaller reels of cable, the first method is preferred.

Today we find that improvements to fiber optic communications technologies have improved to such an extent that signal degradation is much less now than it was at first. Thus, the need for regenerators and optic signal repeaters is only necessary over very long distances of several hundreds of kilometers.

These advances in optical technologies have also contributed to greatly reducing the cost of long span “backbone” deployments particularly for long-haul undersea spans where the cost and reliability of repeaters is a key factor.

To illustrate the degree to which these technological improvements have progressed we can compare the attenuation rates for the “original” fiber optic cables and those commonly deployed today. The original fiber optic cables contained impurities that resulted in attenuation rates of 1000 dB/km whereas, today's cables typically have attenuation rates in the order of 0.3 dB/km. An improvement of many thousand-fold.

Transmission Window - The effects of attenuation and dispersion vary with wavelength. As a result, there are certain regions of the optical spectrum where these undesirable attributes (attenuation and dispersion) are at their weakest. These bands are therefore “desirable” for use in fiber optic communications transmissions and we refer to them as “transmission windows”. The 1300nm window has zero dispersion while the most commonly used window today is the 1500nm transmission window as it has the lowest attenuation losses and hence has the longest effective transmission range.

Here are 10 spectacular inventions that will make a difference in the race to a better environment. If you click on "Image Source" you can read more about the listed items.

Zero Pollution Motor

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Popular Mechanics confirmed that the Tata Motors Company will bring the first air-power cars production to the United States later in 2009 or early 2010. These cars break a 1000-mile-per-fill, and a top speed of 96 mile. The price of this car is estimated at $18,000.

Ivanhoe Reservoir

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In an effort to block the formation of a carcinogen, the Los Angeles Water Department and Power had dropped 400,000 plastic balls into the Ivanhoe Reservoir to protect the drinking water supply for 600,000 customers.

This invention is designed to shade the water from the sun, since sunlight presents a potential harmful mix with bromide and chlorine in this 102-year-old reservoir.

TV Remote Control

This is a TV remote control that powers by human. Japanese firm SMK Corp has invented an eco-friendly device and contributes a significance change to reduce global warming.

This device can turn the power on/off, channels surfing, and controls volume when the user pulls the trigger on the remote control.

Virtually Waterless Washing Machine

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The researchers at University of Leeds have come up with a way to wash clothes that uses less than two percents of water and energy. The washing machine, Xeros, can also remove virtually all types of stains. The clothes come out of this washer are almost dry, thus reduce the need for dryer usage.

Xeros uses as little as one cup of water for each washing cycle!

Green Tower

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These two views of the Green Tower are in Siberia, and designed by Foster&Partners. The tower will be made of glass to absorb as much light as possible during the winter months, and constructs with sustainable materials, which uses renewable energy sources.

Eco-Boat

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Meet Earthrace, a state-of-the-art speed-craft that runs on human fat, beside other biodiesel fuels. The Guardian states that Earthrace runs on 100% renewable biodiesel fuels, and has zero carbon foot-print.

Pete Bethune, a New Zealand skipper of Earthrace, underwent liposuction, and donated enough of his body fat to make 100ml of biofuel.

Eco-Laptop

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The Asus notebook's case is covered in bamboo, and all the plastic inside it is recyclable. There is no paint, no spray, or electroplating uses on its components, and lines with cardboard.

These laptops are scheduled to be release at the beginning of next year.

Water Solar Heater

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William J. Weber wrote this article in Mother Earth News about his experiences with building his own solar water heater, with detailed on materials, and how much it costs, as well as how to construct it.

Chicago Eco-Bridge

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Chicago is on a race to make the city a greener place with many projects under way. The eco-bridge in Monroe Harbor will serve as a recreational space for residents and visitors. The bridge is designed by Adrian Smith + Gordon Gill Architecture, and offers view of the city, rowing and sailing on calm water. It is two miles long, and connects two opposite ends of the city center, and Grant Park.

Floating Ecopolis for Climate Refugees/Lilypad

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Architect Vincent Callebaut called this the Lilypad, but it is also known as the Floating Ecopolis for Climate Refugees since the forecast for the ocean level will rise from 20 to 90 cm. This auto-sufficient amphibious city will become a reality in 2100, and is a future retreat for only 50,000 rich people though.

These fascinating inventions are incredible, and committed to cope with the changes in our environment.