What Are Polarized Lenses

Polarized lenses are transparent pieces of material, usually glass or plastic, that block certain types of light waves. Sunglasses and camera lenses are often polarized to reduce glare from surfaces, such as light reflecting off a lake or the hood of a car. Somewhat like the way Venetian blinds control the amount of sunlight passing through a window, polarization blocks as much as 50% of the light passing through a lens. The person looking through the lens can still see clearly in most cases, but it reduces the brightness and glare of light.

How They Work

When light bounces off of a surface, its waves tend to be strongest in a particular direction — usually horizontally, vertically, or diagonally. This is called polarization. Sunlight bouncing off a surface like water, a road, or metal will usually reflect horizontally, striking the viewer's eyes intensely and creating glare. Most polarized lenses in glasses are laminated with tiny vertical stripes that only allow vertically angled light to enter the wearer's eyes. Glare is eliminated because the horizontal light waves cannot bypass the vertical filter.

Lenses can be polarized to different degrees and in different ways. Most inexpensive polarized sunglasses have a thin film applied on one side of the lens. Many higher quality lenses have film laminated between two layers of lens material, preventing it from being scratched or rubbed off. In addition, the more dense the film is, the more polarization it provides. 

In most cases, polarized sunglasses don't look any different from regular sunglasses. While denser films tend to be darker, the color of a lens does not determine how much polarization it provides. A very dark pair of sunglasses with a light film will not block more glare than a lighter shade of glasses with a denser film. The color of the lens is also variable; although they cannot be made clear, polarized lenses can be made in gray, brown, green, or other colors.

Uses

Drivers, fisherman, and photographers were some of the first to use polarized lenses. Reducing glare can ease the eye strain drivers feel from long hours on the road. Fishermen can often see under the surface of water using the lenses, which helps them to see fish or other objects. Photographers use polarizing filters on camera lenses to enrich the images they capture by giving them more contrast, and to increase the range of effects they can produce.

Using horizontally and vertically polarized lenses together makes one type of three-dimensional (3-D) movies possible. Two images are projected onto a 3-D movie screen: one is polarized vertically and one horizontally. The lenses of the glasses that moviegoers wear are also polarized, one vertically and the other horizontally, so the user sees one image in one eye, and the second, slightly different image in the other. The brain is able to combine both of these images in a way that produces a realistic sense of depth.

Limitations

Polarized glasses do not provide universal protection from glare. If the wearer tilts his or her head past 45° or so, more of the horizontal light can enter and cause bright spots. In addition, these lenses do not usually work with snow glare because snow tends to reflect light equally in all directions, rather than the mostly horizontal reflection off of liquid water. It is strongly recommended that downhill skiers in particular not wear polarized sunglasses; ice does reflect horizontally, and these glasses can make dangerous icy spots less visible.

Because the polarizing stripes reduce the amount of light entering the eye, these lenses should not be used at night or in other situations where clear lenses are required. It is not possible to make such lenses truly clear; even those with low levels of polarization have a slightly gray hue. Some people find that looking through the lenses for too long a period of time can cause headaches and eye strain.

Polarized lenses can cause distortions in the way wearers see liquid crystal displays (LCDs), rendering some cell phone screens, clocks, and other displays unreadable. The texture of laminated or heat-treated glass, like a windshield, can be made more prominent by looking at it through a polarized lens, making the glass difficult to see through. Pilots should not use polarized glasses because they can make flight instruments difficult to read and other objects in the sky — including other airplanes — less visible.

Is It a Good Idea to Buy a Refurbished Mobile Phone

Is it a good idea to buy a refurbished mobile phone? It all depends. A refurbished mobile phone is one that has been returned to the factory from a cell phone company and rebuilt, usually to new specifications. Sometimes, a favorite model will no longer be manufactured new, but a customer can get a refurbished one.

A refurbished mobile phone should, in all respects, work exactly as a new phone. This is probably more likely to be the case when the refurbished mobile phone does not have many complex features, such as a camera, personal digital assistant and Bluetooth® capabilities. Cell phone customers routinely upgrade their mobile phones every couple of years or so, and the old ones have to go somewhere. Some are discarded, if they are no longer compatible with the cellular system, but many are sent back to the factory to be refurbished. This is also the case for phones that malfunction.

Whether buying a refurbished mobile phone is a good idea depends greatly on the manufacturer. Reputable makers usually produce a good product, but this may not be the case with "off" brands. A consumer should also always ask his or her cellular service provider if they have many refurbished phones returned for malfunction. Sometimes, the manufacturer will provide a warranty of some description, but the consumer should insist on one from the service provider. 

The question of getting a refurbished mobile phone may be crucial for someone who needs a phone at a moment's notice and cannot afford to risk having a refurbished mobile phone malfunction. On the flip side of that coin are elderly customers who have a good phone that they like. Many elderly customers don't want to have to learn how to use their phones all over again, and if a refurbished mobile phone in their preferred model is available, they may want one.

Price is another consideration. No customer should be asked to pay top dollar for a refurbished mobile phone. This is not fair. Even if a phone has many features, if it is refurbished, the customer should not have to pay what she would for a new phone. However, cellular service providers are aware of this, and they often offer a refurbished mobile phone as one of the free models for upgrade or for signing a service contract.

The main things a customer needs to consider when thinking about a refurbished mobile phone, then, are quality, warranty and price. If these are resolved to his satisfaction, then buying a refurbished mobile phone may be a sensible purchase.

What is an Unlocked Phone

An unlocked phone is essentially a phone that can be used with any SIM card from any network. Most cell phone companies install special “locking” software on their phones that prevents the phones from being used with any other network’s SIM card. However, there are ways to unlock a cell phone so that it can be used with any network.

One of the ways that cell phone companies attract new customers is to offer free or inexpensive phones when the customer signs a contract. In addition to charging a high termination fee if the customer cancels their phone line before the contract is up, cell phone companies protect themselves by locking all of the phones they sell to their network. This keeps them from losing money on customers who would buy a phone for a good deal from their company, then activate it with another network for a better rate.

Cell phone companies are able to do this because every modern cell phone has a tiny card in it called a SIM card. The SIM card is what identifies a cell phone as a certain phone number. In other words, a cell phone user can move their SIM card from one phone to another and still keep the same number. In addition, the SIM card is coded with the network’s identification information.

A locked phone essentially has software that prevents it from working with a SIM card that has any other carrier’s information coded into it. Unlocking a cell phone therefore enables the phone’s owner to leave one cell phone company for another. With an unlocked phone, a person can use whichever cell phone company is offering the best rate or the highest quality services.

Another advantage is that an unlocked phone is worth more money. Many sellers on eBay and elsewhere sell cellular phones. Since an unlocked phone appeals to a wider audience, instead of only those with a certain carrier, it is often worth the minimal expense to unlock the phone.

Unlocking a phone can be done online for very little money, usually under twenty U.S. dollars. Some phones require a special code to unlock them, which can be purchased online. Other phones can be unlocked by downloading software online and hooking the phone up to the computer. Unlocking a phone is generally not difficult, and since an unlocked phone gives users more options, the time and money it takes is usually considered worthwhile.

What Is Anynet

Anynet is an audio-visual networking system created by the Samsung Electronics Company. Using this system, individuals can link different Samsung devices to one another, or experience various audio-visual files using a standard television. This system makes it easy to network various devices, even for those with no formal electronics knowledge or training. It also provides a single remote for operating a wide variety of system components.

When Samsung introduced the original Anynet program, it was designed to work with up to two devices, plus a television. A few years later, the company introduced a more advanced networking program called Anynet+. Anynet+ works with up to 12 different devices, and uses high-quality HDMI cables to connect these devices to the TV. Users can control a cable box, DVD or Blu-Ray player and home theater system through the Anynet network. With Anynet+, devices such as digital cameras, camcorders, and stereo systems can also be included in the home entertainment network.

The program relies on a special menu built into most models of Samsung televisions. From this menu, users can access and control any connected device using only the Anynet+ remote control. This program provides a centralized location for storing and viewing pictures and home movies. It also allows the user to consolidate various devices into one simple system.

One of the biggest benefits of this program is that it uses only one remote control. Instead of having separate remotes for speakers, cable, and other devices, a single unit can be used for all, which can help to clear up clutter in the home. While using this program, users press a single button to power-down all components instead of turning each device off individually. Best of all, this system makes it easy to connect new devices with a "plug and play" connection. There is no need for complicated wiring or networking, and many homeowners can set up Anynet without assistance.

The main drawback to this system is that it only works with Samsung products, and not all Samsung models are Anynet-equipped. While other electronics manufacturers may have similar programs, they are not interchangeable with one another. Buyers who have some home electronics devices from brands other than Samsung will not be able to use these devices with Anynet. For some users, the hard-wired connection may also be a potential drawback. The use of wires limits connectivity options somewhat, as devices must be close enough to the television to accommodate a wired connection.

What is an iPod

An iPod is a portable device for storing and playing digital media files, and it is designed and produced by the computer company Apple Inc. There are several variations of iPods that are different sizes, have different purposes and use different technologies. For example, some smaller versions are mainly for playing music files through headphones. Other versions have video screens and can play movie files. Some even have touchscreens, can provide Internet access via wireless technology and can double as personal digital assistants (PDAs). Updated versions, or generations, of the various types of iPods are frequently released as the technology and designs improve.

Variations

Released in 2001, the original iPod came with a body of white acrylic glass and chrome. Three years later, Apple released the iPod Mini, which was about one-third the size of the original device and encased in a variety of shiny metallic colors. The Mini was discontinued after a little more than one year and replaced by the iPod Nano. The smallest member of this family of devices, the Shuffle, which was released in 2005, reduced the size to that of a package of stick gum and looked very much like the original. Unlike the original version, the Mini and the Nano, the Shuffle does not have a display screen.

The most versatile version of this device, the iPod Touch, was released in 2007 and features a touchscreen. In addition to being a media player, it functions as a PDA and wireless Internet device. It also can be used as a handheld console for video games.

Storage

Original versions of the iPod — more recent generations use the name iPod Classic — could store 5 gigabytes (GB) of digital files, which was the equivalent of about 1,000 digital music files. Other versions of this line of devices have a range of storage capacities, from as small as 2 GB to more than 150 GB. The Classic and Mini use tiny hard drives for memory, and the Shuffle, Nano and Touch use flash memory.

Content Management

An iPod's content is managed using Apple's proprietary software called iTunes. The device can be connected to a computer, and the owner can use iTunes to transfer media files from the computer to the device and then organize those filed. The Touch can connect to the iTunes Store through the Internet to download media files, most of which are available for a small price, although some might be free. It also can download applications from Apple's App Store, also either for a price or free.

What is an MP3 Player

MPEG-1, Layer 3 (MP3) is a standard for digital audio compression that has been defined by the Moving Picture Experts Group (MPEG). An MP3 file is an audio file that has been compressed using this standard. Strictly speaking, an MP3 player is an electronic device that is made especially for playing these files. In a general sense, however, any electronic device for playing digital audio files might be referred to as an MP3 player, regardless of the actual type of digital files that it plays.

Sizes and Memory

MP3 players come in many sizes and storage capacities, but they typically are portable devices that are small enough to fit easily in the user's hand. Most have enough memory to store hundreds or even thousands of digital audio files, which usually are songs. The files usually are placed in an MP3 player's memory by connecting it to a computer and transferring the files to the device. Some advanced models of MP3 players, however, might allow the user to download the files directly from the Internet.

The smallest MP3 players use a type of memory known as flash. Flash is very compact and uses very little power, allowing for extremely small designs with long battery life. The limitation of flash-based MP3 players is that they do not have a great deal of storage capacity. For larger storage needs, hard disk-based MP3 players were developed. These can have storage capacities of more than 10,000 songs, but they must be larger than flash-based players and generally are more expensive.

Features and Accessories

Many MP3 players have small screens that tell the user the name of the song and other information about it. The screen also might serve as a user interface, allowing the user to execute commands or choose various options. Some of these devices even have touchscreens, which allow their users to tap directly on the screens to make choices or execute commands instead of pressing buttons elsewhere on the devices. Most of these devices come with earphones, and some models have built-in speakers that allow users to listen to MP3s without having to wear earphones.

Digital Hubs

Some non-portable MP3 players also have been developed. Sometimes referred to as digital hubs or media centers, these devices are crosses between stereo components and computers. With network connections — often wireless — they are able to access MP3s and other digital content stored on computers on the network. With a full array of standard audiovisual connections, they are able to integrate with home entertainment systems. These devices typically come with remote controls and might use televisions as display screens for menus and playback information. 

One advantage of these digital hubs is that more than one device can access the files at the same time. All of the files can be stored in the hub, and MP3 players that have wireless connectivity can access the files. This essentially turns an MP3 collection into a music library that has multiple copies of every song.

What is Chemosynthesis

Chemosynthesis is a process certain organisms use to produce energy, akin to photosynthesis, but without the utilization of sunlight. The energy comes from the oxidization (burning) of chemicals which seep up from the Earth's crust. The organisms that use chemosynthesis, all bacteria, manufacture carbohydrates and other organic molecules from the oxidization of sulfates or ammonia. The hydrogen they use comes from hydrogen sulfite, whereas the nitrogen comes from ammonia or nitrates. The organisms that use chemosynthesis are found around hydrothermal vents on the ocean floor. They are adapted to circumstances which would have been commonplace billion of years ago, leading some to call them descendants of the earliest life on Earth.

Organisms that use chemosynthesis are extremophiles, living in harsh conditions such as the absence of sunlight and a wide range of water temperatures, some approaching the boiling point. These organisms are known for living inside one another, engaging in symbiotic and parasitic relationships to maximize their chances of survival. Chemosynthetic microbes provide the foundation for larger communities of organisms which consume the microbes to survive. One interesting example is the tubeworm, filled with billions of chemosynthetic bacteria. The tubeworm starts life with a mouth and gut, which it uses to intake many bacteria. Its mouth then closes and it continues to survive by consuming food produced by its internal bacteria.

Chemosynthetic species are autotrophs, organisms capable of manufacturing organic matter directly from inorganic feedstock. Autotrophs of different types can produce energy either through photosynthesis or chemosynthesis. The gases that autotrophs use to create energy would be poisonous to most organisms. 

They use unusual enzymes capable of resisting high temperatures and pressures. Since these organisms live on the bottom of the ocean floor, they are subject to much pressure from the water above. Ecologies surrounding deep sea vents are extremely prosperous relative to those located further away from such chemical sources, which must survive solely on dead organic matter slowly descending from the waters above.

Chemosynthetic organisms have been viewed by the biotech industry as a means of converting toxic chemicals into harmless organic variants. If life exists on other planets or moons such as Mars or Titan, it has been postulated that they may use chemosynthesis.

What is the Difference Between 720p and 1080p HDTVs

High-definition television (HDTV) is available in both 720p and 1080p models. The difference between them boils down to resolution, with 1080p capable of displaying a higher native resolution than 720p sets. This doesn’t necessarily mean that in all instances a 1080p HDTV will display a better picture than a 720p set. We can thank multiple broadcast formats and the varying quality of electronic components used in HDTVs to complicate the issue just a bit.

First, the basics. Every HDTV has what’s referred to as a native resolution. This is the only resolution the television can display. Every broadcast it receives or digital format it displays (such as a DVD), must all display in the native format. To do this the HDTV converts any signal that differs from its native resolution to the native resolution. Lower resolutions are “upgraded” and higher resolutions are “downgraded.” This process is known as upconverting and downconverting. 

In the switch from standard definition broadcasts to high-definition broadcasts, there are competing formats. Some networks broadcast in 720p (1280 x 720) and others in 1080i (1920 x 1080). A 720p HDTV will be able to display 720p broadcasts natively. Displaying a signal without conversion results in an excellent picture. Once the TV has to convert a signal, the conversion process itself can degrade picture quality. Therefore a 720p broadcast might look better on a 720p TV than on a 1080p, if the processor chip in the 1080p HDTV is not up to snuff. 

Other networks broadcast in 1080i, which the 1080p HDTV can display natively. A 720p set will have to downconvert a 1080i signal before displaying it. Both HDTVs will also have to de-interlace the 1080i signal but this does not involve changing the resolution, only reordering frame display. An interlaced signal is designed to paint every other line on the display, then fill in the missing lines. Progressive scan TVs paint the screen sequentially, from top to bottom, reducing the flicker affect of interlaced signals.

So far it might sound like a wash. A 720p HDTV will display 720p broadcasts natively, and a 1080p will display 1080i broadcasts natively. The 1080p might be seen as having the advantage that it will also upconvert 720p signals to 1080p resolution, and if the internal processing chip is a good one, this should improve picture quality to lessen "stair stepping" and the "screen door affect" by packing more pixels into the image for an overall smoother quality. Meanwhile, the 720p set will have to downconvert 1080i broadcasts

But the real advantage of the 1080p is in watching HD DVD and Blu-ray discs. These digital discs are formatted in 1080p and studio movies on this media played on the 1080p HDTV are astounding. A 720p set that will accept a Blu-Ray signal must downconvert these formats to lesser resolutions, robbing the viewer of the true Blu-ray / HD DVD experience. The 1080p is also a preferable set for gamers who intend to connect a PC, XBox™ or PlayStation™. 

All else being equal, 720p HDTVs are less expensive than their higher resolution siblings. If you aren’t big on DVDs and don’t plan on buying a Blu-ray or HD DVD player, you might opt to save some money. For gamers or movie fanatics, consider the higher resolution set, but stick with a quality brand that will provide a solid upconverter for all of those 720p broadcasts you’ll be watching between movies. Also, be sure the 1080p HDTV provides 1080p inputs or ports. Accepting 1080p input (as from a Blu-Ray player) is a different function than upconverting broadcast signals, and some earlier models lacked the ability to accept 1080p signals.

What is a Dry Cell Battery

The dry cell battery is one of the most commonly used types of batteries. A, C, 9-volt, and watch batteries are dry cell batteries. Invented by Sakizou Yai in 1885, the dry cell battery was improved and patented by Dr. Carl Gassner, a German scientist in 1887. A dry cell battery is different from a wet cell battery because its electrolytes are contained in a low-moisture paste. A wet cell battery's electrolytes are contained in a liquid. Wet cell batteries are often used in cars because they are relatively cheap and easily recharged.

Dry cell batteries, regardless of their size, have the same components. At the center of each dry cell battery is a rod called a cathode, which is generally made of metal or graphite and is surrounded by an electrolyte paste. The cathode and electrolyte paste are wrapped in paper or cardboard. One or more of these cells are sealed into a metal cylinder called an anode, which is typically made of zinc or alkaline.

The anode in the dry cell battery has two or more terminals — one that is positive and one that is negative. When a load is connected to the battery's terminals, a chemical reaction occurs between the cathode and the paste in each cell to produce roughly 1.5 volts of electricity. A battery that has more than one cell will produce a higher overall voltage. After the load has been connected for a long time, the battery's chemicals can no longer react with each other and will therefore no longer produce a charge. 

Alkaline batteries are more popular than their older zinc counterparts because they corrode more slowly and thus hold their charge longer. A less commonly used type of dry cell battery uses silver for the cathode rod. Another type is the mercury cell, which uses mercury in the cathode and is often used to power calculators. Nickel/cadmium (NiCd), nickel metal hydride (NiMH), and lithium-ion (Li-Ion) dry cell batteries are rechargeable, making them popular for use in power-hungry digital cameras and portable electronics.

All batteries contain chemicals that are harmful if released into the environment, so all used dry cell batteries should be recycled properly. Many municipal recycling programs accept batteries. Consumers should also consider using rechargeable batteries because they can be reused many times and can also be recycled after they no longer hold a charge.

What Is 4G

4G, an acronym for fourth-generation wireless, is a type of technology that can be used with cellular phones, wireless computers, and other mobile devices. This technology give users faster access to the Internet than most previous third-generation (3G) networks can offer, and it also offers new user options such as the ability to access high-definition (HD) video, high-quality voice, and high-data-rate wireless channels via mobile devices. In 2009, the ITU Radiocommunication Sector (ITU-R) defined the standards for the successor to 3G: the new technology must provide peak speed for Internet communication at 100 megabits per second (Mbps) for high mobility users, which includes those in cars and trains, and 1 gigabit per second (Gbps) for low mobility users, such as pedestrians or those who are stationary while using their device. Like previous generation technologies, the newest version is not expected to be fully incorporated worldwide for several years.

New Services

The fourth-generation wireless technology provides a wide variety of services including the option to download, view, and upload high-definition (HD) videos, which could potentially change the way some companies do business; video conferences could become more common, for example. High-quality voice when using a cellular phone is another added benefit of 4G technology, as well as access to high-data-rate wireless channels. 4G is also known as "beyond 3G," since it provides a comprehensive and secure Internet Protocol (IP) solution. Users have access to high-quality streaming video and "anytime, anywhere" voice and data at a much higher speed than previous generations. The "anytime, anywhere" solution of 4G technology is also referred to as "MAGIC," which is an abbreviation for Mobile multimedia; Anytime/anywhere; Global mobility support; Integrated wireless solution; and Customized personal services.

Objectives

The 4G working group has defined several objectives of the fourth-generation wireless communication standard. This includes a high mobility rate of 100 Mbps between any two points in the world, seamless connectivity allowing users to enjoy global roaming across multiple networks, and support for using high-quality multimedia. Perhaps users will be willing to purchase the technology as it is said to be up to ten times faster than previous 3G options, with broadband accessibility in rural areas that previously lacked high-speed internet capabilities.

The fourth-generation will inter-operate with third generation systems and broadband broadcasting systems; it also intends to integrate fixed wireless access (FWA), wireless local area network (WLAN), wireless local loop (WLL) and personal area network (PAN), to provide fully IP-based wireless internet. When fully implemented, this technology could help create additional markets and opportunities for new and established telecommunication enterprises. A 4G network can potentially open the gates of video blogging on mobile phones when combined with cell phones that are equipped with advanced HD capabilities, or high-quality digital cameras.

Development

With a higher data rate and broader bandwidth capability, 4G technology focuses on providing seamless service across a multitude of wireless networks and systems. Some of the core technologies employed by fourth-generation wireless include Orthogonal Frequency Division Multiplexing (OFDM), Software-Defined Radio (SDR) receivers, Orthogonal Frequency Division Multiple Access (OFDMA) Universal Mobile Telecommunications System (UTMS), and multiple input/multiple output technologies (MIMO). Together, these technologies could ensure high rates of data transmissions for 4G users, though the availability may not be offered everywhere for several years.

What Should I Do If My Cell Phone is Stolen

If your cell phone is stolen, the first step is to suspend your account so people cannot make expensive calls or texts to others using your phone. Depending upon the type of service you use, you may either need to call the service or use their Internet reporting service to stop the line from working. Most believe that this should be done as soon as possible, since people can immediately begin to make expensive calls from your phone. Failure to report promptly if your cell phone is stolen could mean you are responsible for some of the calls made by the thief.

Many cell phone companies also sell additional insurance that can help one cover these costs if your cell phone is stolen. Some cell phone insurance also can cover the cost of replacing the phone. If you purchased your phone and contracted with a service at the same time, you may have to spend significantly more to replace the phone. Cell phone companies often offer excellent deals to new customers, but for established customers, a brand new cell phone can come at a high price, especially if is replacing an elaborate or expensive phone.

Cell phone insurance may also be purchased from private companies and help to protect call costs and materials if your cell phone is stolen. However, be certain not to pay for double insurance. For example, some home and renter’s insurance, and some auto insurance may cover replacement of a cell phone. If your cell phone is stolen from your vehicle or home, you may be eligible for replacement under one of these plans. However, if your cell phone is stolen when you are outside, you may not have coverage under these plans.

If your cell phone is stolen and is a prepaid phone, you can still request that service be stopped to the phone. However, your cell phone will stop working the moment the thief runs out of pre-purchased minutes. In these cases, you might want to risk the minutes for a day or two, to see if anyone has merely found your cell phone and wishes to return it to you. It’s a good idea to keep your home number listed in your call list, so that someone who finds a lost phone has the chance to return it to you.

With many prepaid services, replacing the cellphone is less expensive, provided the model you use is fairly simple. It may not be worth it to purchase cell phone insurance. More expensive phone models may make insurance well worth the cost. The cost of replacing your phone may not be worth the insurance expense if your cell phone is stolen. However, you should still report the theft to both your cell phone service provider and your local police department if your cell phone is stolen, at least within a few days, since the company can then make it impossible for someone to have your number, receive your calls, and purchase new minutes on the phone. 

About one in four cell phones are lost, damaged or stolen. Cell phone insurance often covers you not only if your cell phone is stolen, but also if it is lost or damaged. You should treat a lost phone as if your cell phone is stolen. Report the loss and hope for the best. It is often possible to reinstate the line if your phone is returned to you, or if you find it on your own.

What is a Cell Phone App

A cell phone app is the cool way of saying cell phone application. These applications are add-ons or bits of data added to a cell phone so it can perform functions usually unrelated to making a phone call. Cell phones always did come with a few extra things unrelated to making phone calls, but these have greatly expanded, and now many people download the extra the apps they want. 

Many of the early cell phone app programs were designed to make a cellphone more like a computer. They often integrated some of the computer elements into the phone. While many of these early programs continue to be updated and used to track things like business performance or email, they are only the tip of the iceberg in modern cell phone app offerings.

Applications on a cellphone can provide the phone with additional function and use. For instance, people can now surf the net, blog, contribute to their twitter accounts, or play simple to complex games. A cell phone app might be able to find the location of a friend or turn the phone into a calculator. There are even SAT study apps, and ones that can teach people various subjects or help with studying for school.

Some of the very interesting cell phone apps may be of great help in the medical field. For instance, an app can be used to record heart rate over a period of time and send this to a doctor for review. Some cell phones have a tracking mechanism for blood sugar that can be useful for diabetics. 

A few cell phone apps are more for entertainment than serious purpose. Taking their cue from MP3 players, many cellphones now allow people to find the name of song, download a song, and/or play music just as an MP3 player does. Certain apps allow people to play games together over separate cellphones. 

The increase in the cell phone app market has been in part due to advancements in cell phone design. Especially any version of the smartphone, where the phone is more complex in design and has many elements in common with a personal computer, is better able to run apps and lots of them. For instance, companies like Apple® have an app store, with applications best suited for the iPhone®. Other companies are certainly following suit, and the number of potential apps available is fairly daunting; over 10,000 are available for the iPhone® alone.

Since most cellphones aren’t suited to holding every cell phone app, it may be wise to use some discretion when choosing which ones to purchase for a phone. They aren’t always compatible, either. A cool Blackberry® app may not run on an iPhone® and vice versa.

What is a Thumb Drive

Computer users long complained that 3-inch floppy disks were too unstable, the ZIP drive not practical and CD-Rs not portable enough for data storage. The technology geeks solved this problem in ingenious fashion: the thumb drive. IBM came out with thumb drives in 1998, as a solution for replacing the less stable floppy disks. Their use caught on quickly, and as portable data storage has become more of an issue, thumb drives or flash drives skyrocketed in popularity. They can now be seen hanging on lanyards around the necks of computer users everywhere.

A thumb drive is portable memory storage. It is re-writeable and holds its memory without a power supply, unlike RAM. Thumb drives will fit into any USB port on a computer. They will also "hot swap," which means a user can plug the drive into a computer and will not have to restart it to access the thumb drive. The drives are small, about the size of a human thumb - hence, their name - and are very stable memory storage devices.

At first, some users saw their lack of compatibility with Windows 98 as a drawback of thumb drives, since so many users were still running that operating system when the drives were introduced. However, most thumb drives came equipped with software that installed a Win98 driver on the computer, enabling the user to connect a thumb drive. Installing the software took about 60 seconds. Thumb drives also pose security threats, since they are easily concealed. Users could copy proprietary information to them, or upload hacking software from them, all undetected by the system administrator. 

However, system administrators can also upload anti-virus software to an infected computer from a thumb drive, for instance, without risking the system servers. Their write speeds and read speeds only really come into play when users are running large applications from them. When the user is saving text documents or photos, for instance, these speeds are not nearly as important. Most thumb drives also have millions of re-write cycles and will store data for ten years before they need replacing.

The thumb drive is available in storage sizes of up to 16 gigabytes. Most people, however, will find that sizes of 256 megabytes to 512 MB will do nicely. If the person is storing mostly text, with few images, then an even smaller thumb drive may meet the need.

A thumb drive is available anywhere computer supplies are sold. They range in price from about US$15 to $75 or so for a large-capacity drive. They are stable, versatile, durable and portable data storage devices. As such they are ideal for almost any computer user who wants safe, long-term storage for a low price.

How Does Infrared Work

Infrared (IR) light is a wavelength of energy that is invisible to the human eye. The most common source of this energy is heat; objects can have their relative temperatures measured by how much of this energy they give off. Lower wavelengths or "near infrared" — closest to the visible light color red — are not hot, and are often used to transmit data in electronics. A remote control, for example, may use a particular wavelength of near infrared to communicate with a receiver, sending pulses of light that transmit a signal to the device, telling it what to do.

Description and Measurement

A form of energy, IR is part of the electromagnetic spectrum. This spectrum is comprised of radio waves; microwaves; infrared, visible, and ultraviolet light; x-rays; and gamma rays. Each form of energy is ordered by wavelength; infrared falls between microwaves and visible light waves because its waves are shorter than microwaves but longer than those of visible light.

The prefix infra comes from the Latin word which means "below;" the term means "below red," indicating its position in the electromagnetic spectrum. Visible light has a range of wavelengths that are manifested in the seven colors of the rainbow; red has the longest wavelength and violet has the shortest. Infrared, with wavelengths longer than the color red, is invisible to the human eye.

Just like with visible light, there are a range of wavelengths of IR. The International Commission on Illumination has divided it into three general sections based on the length of the wave and density. These groups are commonly known as near, medium, and far infrared, with near infrared being nearest to the visible light side of the spectrum and far, or long-wave, infrared being close to the microwave zone. There are uses for IR wavelengths in each group, from wireless communication to acting as heat source.

Applications of Infrared

Nearly all objects emit heat or energy, and one of the most easily discernible forms of energy is infrared. When an object is not hot enough to give off visible light, it emits most of its energy in the IR spectrum. It is this heat that affords IR many applications in almost every sector of life, including health, science, industry, art, and entertainment.

Converting infrared energy, also known as radiant heat, into an image that the human eye can see and understand is done with a process called thermal imaging. An IR camera is used to accurately measure the temperature of an object, which is then translated into color. For example, infrared imaging typically shows the warmest areas in a human body as red, followed by yellow, green, blue, and violet as the temperature decreases. By studying how body heat is distributed, thermal imaging can health professionals to analyze body tissue and fluid to detect injury or disease.

Infrared light is used in night vision equipment, allowing the user to see in the dark. Two types of night vision both use IR: thermal and image-intensifying. Thermal night vision allows the user to recognize people and objects by the heat pattern they emit. Intensifiers amplify existing light — including infrared — to allow the user to see.

As a way to measure temperature, IR is used in many different types of applications. The military uses infrared sensors to locate and track targets or to detect hidden land mines or arms caches. Infrared sensors on satellites are used for environmental monitoring, pinpointing areas of pollution, fire, or deforestation. Search and rescue operations use IR extensively to locate missing persons lost in the forest or jungle, as well as in collapsed buildings or at the site of other disasters.

Many remote control devices in homes use infrared. These remotes use infrared light to carry signals between a remote control transmitter and the device it's commanding. The transmitter sends out light in pulses, which are translated into binary codes that have corresponding commands. The receiver is positioned on the front of the device, where it receives these pulses of light and decodes them into binary data, which is understood by the microprocessor inside the apparatus. 

Many different types of scientists use infrared in their work, from astronomers use it to learn more about galaxies light years away to archaeologists who use it when studying ancient settlements. Infrared is being used to preserve, restore, and conserve valuable historical and artistic works as well; the invisible details of ancient fragments and images painted under paintings are being brought to light through the use of IR technology. In industry, thermal imaging is invaluable in testing and monitoring mechanical systems.

What is the Difference Between NTSC and PAL

Some Americans may have sent video home movies to a European relative, only to discover that the images are scrambled and the sound quality is very poor. This is caused by a major difference in broadcast formats used by the United States and many other countries. The United States favors a format called NTSC, which is short for National Television Standards Committee, while Europe, Australia and parts of Asia use a competing format called PAL, or Phase Alternating Line.

Most of us would not be able to recognize the difference between NTSC and PAL, but then again most of us aren't television broadcast engineers. The differences really start with the electrical power system behind the transmissions. In the United States and other countries, electrical power is generated at 60 hertz, so for technical reasons the NTSC signal is also sent out at 60 'fields' per second. Since most televisions use an interlaced system, this means that 30 lines of the image are sent out, followed by the alternating 30 lines. This line alternation happens so fast that it becomes undetectable, much like a film running through a projector. The result for an NTSC television is 30 frames of a complete image appearing every second.

Since Europe uses a 50 hertz power supply, the equivalent PAL lines go out at 50 fields per second, or 25 alternating lines. PAL televisions only produce 25 complete frames per second, which can cause some problems with the proper display of motion. Think of it as the 'silent movie effect', in which the actors seem to move a little faster because there are fewer frames showing movement. If a PAL movie is converted to an NTSC tape, 5 extra frames must be added per second or the action might seem jerky. The opposite is true for an NTSC movie converted to PAL. Five frames must be removed per second or the action may seem unnaturally slow.

Another difference between NTSC and PAL formats is resolution quality. PAL may have fewer frames per second, but it also has more lines than NTSC. PAL television broadcasts contain 625 lines of resolution, compared to NTSC's 525. More lines usually means more visual information, which equals better picture quality and resolution. Whenever an NTSC videotape is converted to PAL, black bars are often used to compensate for the smaller screen aspect, much like letterboxing for widescreen movies. 

When the NTSC format was first adopted in 1941, there was little discussion of color transmissions. When the technology for color television arrived, engineers had to create a broadcast method which would still allow owners of monochrome television sets to receive a picture. Color signals on the NTSC format are still not considered ideal by electronics experts. The PAL system, on the other hand, was created after the advent of color broadcasting, so color signals are much truer to the original image.

For most purposes, the difference between NTSC and PAL signals are negligible. A European television set won't work in the United States and an NTSC formatted DVD won't play on a PAL player. But many people own home movies which cannot be viewed on a competing format. For this reason, there are a number of companies which offer conversion kits from NTSC to PAL or PAL to NTSC. Some of these conversion methods can be time-consuming and variable in quality, but others provide an easy way to create a PAL video for a European relative or an NTSC DVD for a Canadian friend. Some electronic media outlets may also provide conversion services for a price.

What Is the Difference Between a Line Conditioner and a Surge Protector

The difference between a line conditioner and a surge protector mostly lies in their intended function. A line conditioner takes in power and modifies it based on the requirements of the machinery to which it is connected. A surge protector doesn't alter the power flowing through it at all, unless that power is over a certain amount. When the power exceeds the set amount, it blocks it from passing through. It is not uncommon for a line conditioner and a surge protector to be in the same unit.

Both a line conditioner and a surge protector are important parts of modern electronics. They protect the inner workings of devices, often without users even realizing. Many people go the extra step of placing these devices between the wall outlets and connected devices to create an additional layer of protection.

A line conditioner modifies voltage as it passes through. Some systems require very tight or nonstandard power tolerances. These devices use line conditioners to alter the power to meet their requirements. They are also a common method of prolonging the lifespan of electric devices, as the properly formed electricity creates less wear of the internal parts of the device.

Most electric systems have line conditioners built into them. These units are usually very small and integrated right into the circuit board inside the device. They monitor the voltage moving across the board and keep it within tolerance. Larger line conditioners exist, ranging from small ones in high-end surge protectors all the way to car-sized industrial units connected to factory machines.

Surge protectors prevent power overloads. When power exceeds a certain amount, they stop it from passing through. Different surge protectors do this in different ways, but the most common method is creating a shunt to a ground wire. 

This connection to the ground only happens when the power is prevented from passing through the unit; otherwise, the unit would constantly waste electricity. If a surge protector is improperly plugged in, such as through a two- or three-pronged adapter, it cannot send power to the ground. In this case, the surge protector may overload and catch on fire or even send the surge through to the connected device.

It isn't unusual for a line conditioner and a surge protector to exist in the same unit. Since these systems both work on passing voltage, it is logical for them to exist together. Some systems only possess a very advanced line conditioner that works as a surge protector when needed; this is common in battery backup systems. In either case, both a line conditioner and a surge protector are important aspects of safe electric device use.

Who Invented the Refrigerator

Refrigerators are an essential part of every modern kitchen. While just about every home makes use of a refrigerator, most consumers know nothing about the history of refrigeration and the invention of the refrigerator. The gradual creation of the modern refrigerator actually spans a process that began in the 18th century and culminated with the work of German engineer Carl von Linden in 1876.

The first efforts that eventually led to the modern refrigeration process that continues to form the basis for the fridges that grace kitchens all over the world today. William Cullen of the University of Glasgow first developed a process to create an artificial cooling medium in 1748. At the time, there did not appear to be much interest in applying the medium to use in commercial or home applications, so the process created little in the way of interest beyond the scientific community. It would take the better part of a century before someone would apply the basic principles discovered by Cullen and create a design for a refrigerating machine. 

Created in 1804, the design was the work of an American inventor by the name of Oliver Evans. However, no working prototype appeared until 1834. At that time, Jacob Perkins built a refrigeration machine that is often thought to be the forerunner of the modern refrigerator. A decade later, John Gorrie designed what is thought to be the first practical refrigerator. In 1844, Gorrie, a physician in the United State, constructed a working unit based on the design of Oliver Evans. Gorrie created the unit as a means of cooling the air in facilities he set aside for patients who were diagnosed with yellow fever. Many people credit Gorrie as being the individual who for all practical intents and purposes invented the refrigerator. 

Carl von Linden discovered and patented an improved method of liquefying gas in 1876, which made the process of manufacturing refrigerator models practical. Making use of such gases as ammonia, sulfur dioxide and methyl chloride, the new process formed the standard for cooling agents until the late 1920’s. By then, a number of accidents related to the use of these substances as cooling agents convinced manufacturers that a more stable element was needed. This effort led to the development of freon, which provided the standard for cooling agents for the bulk of the remainder of the 20th century, until the substance was leaked to damage to the ozone layer. 

From the simple working model created by John Gorrie in 1844 to the modern fridge units of today, the refrigerator has become one of the appliances that is an integral part of our lives. From storing our favorite foods to providing refreshing ice, the refrigerator is one device that most of us would not want to live without.

How Does a Television Work

A television produces a series of tiny dots on a screen that, when seen as a whole, appear as an image. Older televisions rely on a cathode-ray tube to produce images, and operate with an analog signal. As technology has advanced and broadcast signals transitioned from analog to digital, plasma and LCD (liquid crystal display) televisions were created. These TVs are more compact and have crisper pictures than their cathode-ray counterparts because they use a thin grid of pixels to create images rather than a vacuum tube.

The Eyes and the Brain

Most kinds of television work from the same basic principle. The tiny dots of light produced on the TV screen, called pixels, flash according to a specific pattern provided by the video signal. A person's eyes transmit this pattern to the brain, where it is interpreted as a recognizable image. The television set refreshes these patterns hundreds of times per second — faster than the human eye can see — which gives the illusion of movement.

The Cathode-Ray Tube

The cathode-ray tube (CRT), the oldest version of the television, consists of a vacuum tube with a narrow end and a wide end. The narrow end contains an ion gun, which shoots out a series of charged particles of electricity. A series of electromagnets guide the particles to specific points on the wide end of the tube, the screen that viewers look at. Phosphors, substances that light up when a charged electrical particle hits them, coat the screen's inner surface. The ion gun essentially sprays the image at the screen, much like a paint gun sprays paint onto a surface.

Different kinds of phosphors produce different colors, but for color television, only red, blue, and green are needed. Using these colors in various combinations and intensities can create all the colors the human eye can see. As energy travels from the ion gun to the phosphors, it is filtered to strike the exact point on the screen needed to produce a specific hue. In combination, all of these colored pixels create a color image.

Cathode-ray tubes are quite heavy due to the large amount of glass they contain, and relatively inefficient, especially when used in large-screen televisions. For this reason, new technologies were developed to make lighter sets with crisper images. In addition, the development of high definition (HD) digital broadcast signals made bigger screens more popular since the images were of higher quality. Plasma and LCD televisions were created in response.

The Plasma Screen

A plasma screen television consists of a number of tiny cells filled with neon and xenon gases. Each cell is linked to an electrode, which, when fired, excites the gases contained in the cell. The gases emit charge particles, much like the ion gun, that interact with phosphors coating the glass inside each cell. The phosphors light up, creating the image seen on the television screen. The large number of cells in a plasma screen makes for a great number of pixels, rendering a clearer and brighter image.

Compared to other technologies, plasma TVs produce some of deepest blacks, which means that the contrast ratio is very high. They also have very high refresh rates, so images with a lot of motion don't blur as they can on other televisions. If the image remains static, however, it can burn into the screen, creating a permanent discoloration; this is more common in older plasma TVs, and can also occur with CRT screens. Plasma screens can be set to be very bright, which requires a lot of electricity. They also tend to be thicker than LCD televisions, although much thinner than CRTs.

The LCD Screen

LCD televisions also use cells to create images. Rather than exciting gases as plasma TVs do, however, the cells contain a set of red, blue, and green filters covered by a layer of liquid crystals sandwiched between two pieces of glass. Depending on the display type, each cell is linked to either electrodes or thin film transistors (TFT), which trigger the necessary cells to create the image. A backlight — most often cold-cathode fluorescent lamp — lights up the screen so the image can be seen.

While LCDs are very light and thin, they are subject to "dead" pixels, where one or more cells on the screen do not change. Viewing LCD screens from an angle can also lower the picture quality. They have slower response times than plasma or CRT televisions as well, so images can "ghost" or blur in movement.

More recent versions of the LCD television use light-emitting diodes (LEDs) as the light source rather than cold-cathode fluorescent lamps. LED televisions require less electricity than regular LCD screens, and take up even less space. Also, LEDs generally emit a brighter white light, making these screens especially vivid.

What Is Cell Phone Etiquette

Cell phones have become an unavoidable part of modern life for many people, but their presence in so many places can lead to situations in which users are inconsiderate of others. Just as general rules of etiquette vary among cultures, so do rules of cell phone etiquette. Still, some basic principles cross cultural norms — common sense and courtesy are the cornerstones of polite cell phone use. Respecting public and personal space, maintaining privacy, and not disturbing others are some general principles a person should keep in mind when using a mobile phone.

Public vs. Private Use

Cell phone etiquette is usually at its most important in public spaces, where one loud talker can disturb a large number of people. How a person uses his or her phone in more private situations matters too, however, to those who are concerned with being considerate. Many people find it rude when someone takes a cell phone call on a date or during a private social engagement with others. Along the same lines, it's usually thought to be inconsiderate to take a call in the middle of a conversation; if the caller were there in person, he or she would likely wait to politely interrupt at a more appropriate time. When in a small group or one-on-one situation, it's best for someone receiving the call to not pick up unless it's an emergency.

Focus on the Situation, Not the Call

Public settings such as restaurants, waiting rooms, and subways are usually bad places for casual cell phone conversations. Unless the user is expecting an important call, it would be best to put the ringer on vibrate or silent mode and let any calls that do not need to be answered immediately go to voice mail. This is not only more considerate to other people in the public space, but it also helps the caller maintain his or her privacy by not divulging personal information in public.

It is also generally considered poor cell phone etiquette to stay on the phone when dealing with cashiers or customer service people. If using the phone in a supermarket or other store, the person should hang up before going to the checkout lane. In a casual restaurant, it's usually considered impolite to both the counter staff and the person on the other end of the line to stop in the middle of a conversation to place an order.

Although cars are usually considered private spaces, taking a call while driving is usually not a good idea. A number of jurisdictions ban cell phone use while driving unless a hands-free system is used. Even when a driver does not have to physically hold the phone, however, studies suggest that drivers who talk while they drive tend to focus less on the road and other cars and more on the conversation. Most calls can wait, but if one can't, it is safer for drivers to pull over before answering.

Important Phone Calls that Can't Wait

If the cell phone user thinks a call might be important, he or she should try to step outside or find a secluded area to take or return a call. For urgent calls that cannot be missed, polite cell phone users should try to keep their voices low and the conversations brief. If the call interrupts a conversation, it's best for the person to apologize before stepping away to answer.

Cell phones typically have sensitive microphones that can pick up a soft voice while blocking out ambient noise, so yelling into a cell phone is usually not necessary. When people are nearby, polite cell phone users try to keep their voices low and the tone unemotional and even. Arguing or airing dirty laundry in public is almost universally considered to be poor cell phone etiquette.

Maintaining a distance of at least 10 feet (3 meters) from the nearest person when talking on a cell phone is usually a good idea. No matter how quiet the conversation, if a person is standing too close to others, it may force them to overhear what is being said. If it's necessary for a person to speak loudly to be heard by the person he or she is speaking to due to a noisy location, it's probably not a good place to be taking the call.

Places Where the Phone Should Always Be Turned Off

In almost all cases, phones should be turned off in movie theaters, playhouses, observatories, or any other public place where an audience's attention is focused on a performance or event. A ringing phone or a conversation can be very disturbing to other audience members, who have often paid money for the experience. In some cases, performances have been stopped in progress as the performers wait for an audience member to leave or silence his or her phone.

Phones should be turned off anywhere in which silence is important and disruptions should be kept to an absolute minimum. This includes courthouses, libraries, places of worship, doctor's offices, weddings, and funerals, where a ringing phone could indicate a lack of respect. It's also best to turn off a phone during a job interview, as it can suggest that the person being interviewed is more concerned with personal issues than the job.

Ringtones

Loud and distinctive ringtones are good for catching the phone owner's attention, but they can be a major distraction to other patrons in a restaurant or theater. If a phone must be left on in a public space, the owner should put the ringer on silent or vibrate whenever possible to create the least disturbance. Turning the volume down or even changing the ringtone to one that is more subtle — such as the sound of bells ringing rather than the latest pop song — may also cause less of an interruption.

Texting and Surfing the Web

Using a smartphone to text someone or look something up online is usually appropriate in public spaces, as long as doing so does not disturb others. Smartphones often have very bright screens, and can even be used as flashlights in some cases, so using them in a dark environment like a movie theater can be very distracting. Watching videos or playing music without headphones is also likely to be a disruption in any public space, and should be avoided. Many smartphones also include games, which should only be played in public if they do not include loud sound effects or are likely to result in the player making a lot of physical movements or vocal reactions. 

Just like taking a phone call in the middle of a conversation would likely be considered impolite, focusing on the phone's screen to check sports scores or email while talking to others is usually bad cell phone etiquette. If an email or text must be responded to, the cell phone user should apologize and excuse himself to do so privately. Texting or surfing the Internet should never be done while driving.

What is Wiselink

Wiselink™ Pro is a Samsung® technology built into some of their large-screen television models. These models are equipped with a Universal Serial Bus (USB) port to accommodate external storage devices such as flash drives, flash card readers, and MP3 players. Using Wiselink, one can play sound files, view digital photographs or watch multimedia clips or movies. Function varies between original Wiselink and Wiselink Pro, and might also vary between models, depending on which flavor of Wiselink is incorporated.

To use Wiselink, simply plug a device into the USB port then switch the television to the Wiselink mode. This mode interacts with the USB port by providing various kinds of controls and options. For example, one can navigate through simple menus to engage a slide projector function to view a folder of vacation photos in JPEG format.

With the television at the heart of today’s entertainment center, the Wiselink port also allows easy access to the attached multi-channel, surround sound system. MP3 music players with the ability to hold one’s entire music library can be played through the best system in the house without need of a proprietary external speaker system. However, Samsung’s website states that Wiselink does not support the iPod®. To get around this, non-proprietary MP3 players are very inexpensive and could be used in the iPod's stead for this purpose.

Samsung’s Wiselink Pro also supports video codecs: MPEG1, MPEG2 PS/TS and MPEG4/H.264, making it possible to watch home movies downloaded from the digicam to flash storage devices. Without the USB port, one either has to drag out audio and video cables to connect the movie camera directly via auxiliary ports on the television (not always conveniently located), or burn movies to a compact disc or DVD. USB conveniently allows for more spontaneity in sharing holiday, wedding, birthday, graduation or vacation movies with friends and family. 

If you’ve downloaded purchased movies or television programs to your PC, you can copy them to a memory stick and pop the stick in the USB port to watch these shows on your entertainment center. Never mind the expense and hassle of buying blank DVDs and taking the time to burn each program or movie to disk. With Wiselink your movie library can remain in a convenient, portable file format.

Samsung televisions and Wiselink might be upgradeable through firmware. Supported formats might also change with time, as could other features of this interoperable technology.