Pen Drive

Sometimes referred to as a jump drive, the pen drive is a portable USB flash memory device that can be used to quickly transfer audio, video, and data files from the hard drive of one computer to another. With a construction that is small enough to fit into a pocket, the pen drive derives its name from the fact that many of these USB drive devices resemble a small pen or pencil in size and shape.

Pen drives are classified as NAND style data storage devices. Equipped with a large amount of memory capacity, the pen drive is considered to be an improvement on both the older floppy drive disks and the more modern compact disks that are often used to copy data and reload the files on a different hard drive. Even a pen drive with a relatively low storage capacity tends to provide plenty of space for a number of files. The types of files that can be loaded onto a pen drive are all the common types that can be housed on any hard drive. This makes it possible for persons to copy photos, spreadsheets, word processing documents, movie clips, music tracks, and just about any other type of file.

Utilizing a pen drive is a simple task. One end of the drive is equipped with a USB connector at one end. The connector is inserted into the USB port on a desktop or laptop and activated. Once the pen drive is in place, it is possible to drop and drag files into the memory of the drive, or forward the files to the drive. The process is no more difficult than attaching files to an email or copying files onto a disk.

Because there are several different operating systems in common use today, there are various types of levels of the pen drive that are configured to work with each system. Even persons who are using an older operating system can usually find a pen drive that is compatible. As long as the desktop or laptop is constructed with a USB port, and the pen drive is compatible with the operating system, the pen drive will provide practical and easy transmission of data from one hard drive to another one in a matter of minutes. 

Optical Disk

An optical disk is a compact disk or CD. The formatting of the optical disk will dictate whether it is a DVD, CD, read-only or rewritable. Optical disks have replaced vinyl records, cassette tapes, videotapes and floppy disks.

The optical disk became the preferred medium for music, movies and software programs because of its many advantages. Compact, lightweight, durable and digital, the optical disk also provides a minimum of 650 megabytes (MB) of data storage. A double-layered and double-sided DVD optical disk holds up to 15.9 gigabytes (GB) of data.

The optical disk is so named because its technology is based on light. As the disk spins, a laser beam follows a spiraling trail of pits and lands in the plastic material of the disk. The pits reflect light differently than the lands, while a device translates the reflective difference to bits of "on/off" or 1 and 0. The bits form bytes that carry the digital code of the data stored on the optical disk.

A standard optical disk measures 4.724 inches (120 mm) in diameter and .0472 inches (1.2 mm) in thickness. It is made from polycarbonate with a reflective layer of aluminum, coated in lacquer. The master optical disk is made from glass. Nickel stampers are produced from the glass master and used in an injection-molding machine to "press" or produce multiple copies of the optical disk for distribution. If the disk is double-layered, there will be stampers for each layer, after which the two layers must be bonded together. A double-sided disk requires different stampers for each side, in addition to each layer.

Notwithstanding music, movies and digital photographs, the optical disk is increasingly being used for data storage such as backup and archiving. Instant access to files and the ability to use a built-in DVD player all make the optical disk a superior choice over legacy tape backup units for the average computer user.

A blank optical disk can be purchased in many formats. The least expensive will be an audio CD, as these are single-sided, single layered, and not rewritable. DVDs are more expensive, with a double-sided, double-layered optical disk being the most expensive. Before purchasing this type of optical disk, be sure that your DVD player can handle the format. Blank disks are available nearly everywhere music, DVD movies and computers are sold, including discount department stores.  

Modem

Modem, short for modulator-demodulator is an electronic device that converts a computer’s digital signals into specific frequencies to travel over telephone or cable television lines. At the destination, the receiving modem demodulates the frequencies back into digital data. Computers use modems to communicate with one another over a network.

The modem has significantly evolved since the 1970s when the 300 baud modem was used for connecting computers to bulletin board systems (BBSs). With this type of modem each bit, represented digitally by a 1 or 0, was transmitted as a specific tone. The receiving modem responded with its own dedicated frequencies so that the modems could “talk at the same time.” The technical term for this type of modem is asynchronous.

While the 300 baud modem could transmit about 30-characters per second, fast enough for text-based BBSs, people were soon sharing programs and graphics. This required faster modems, and the modem went through many incarnations in rapid succession over the following three decades. By 1998 the standard dial-up modem maxed out its transmission range at 56 kilobits per second. While many tens of times faster than the 300-baud modem, far greater speeds could yet be reached with an Asymmetric Digital Subscriber Line (ADSL) modem.

The designation asymmetric simply means that the modem is faster at downloading (getting data), than uploading (sending data). The ADSL modem has significant, immediate advantages over the dial-up modem. Though it uses a standard telephone line like a dial-up modem, it does not tie up the line, making it possible to use the telephone while cruising the Internet. ADSL service is an “always on” connection, unlike a dial-up modem that cannot be left connected indefinitely. Finally, the ADSL modem is far faster than a dial-up modem.

The ADSL modem can accommodate a telephone conversation because of available bandwidth on the dedicated copper wire, which runs from households and businesses to the telephone company (Telco). A parallel can be made to a multi-lane freeway with several lanes open for additional traffic. The ADSL modem uses the additional lanes (higher frequencies) without interfering with existing voice traffic. An ADSL modem requires ADSL service through an Internet Service Provider (ISP). This type of modem will not work with a dial-up account.

Some businesses require as much bandwidth going upstream as downstream. This means they need to upload large files or programs to the Internet, as well as download large files. For equal bandwidth in both directions, one would need a Symmetric DSL (SDSL) account and SDSL modem. The SDSL modem uses voice traffic lanes to expand bandwidth, and therefore a conversation is not possible when the SDSL modem is connected. For this reason most businesses use a dedicated phone line with an SDSL modem.

Yet another type of modem uses cable TV wiring rather than the phone line to provide Internet connectivity. A cable modem requires service from a cable TV provider for Internet connectivity. The cable modem works on the same principle as the DSL modem, in that digital data is transferred across wires using frequencies that are translated back into digital data. Frequencies used for data traffic do not interfere with existing TV traffic.

A less common modem is a satellite modem, or sat modem. The satellite modem converts digital data into radio waves to communicate with a satellite dish. This not only involves a built-in latency factor in most cases, but the service is more expensive than more conventional types of Internet connectivity. A satellite modem can be an option, however, for businesses or enthusiasts in rural areas that do not yet have DSL or cable service offerings.

While most DSL and cable providers offer a modem with Internet service, the subscriber can also opt to provide his or her own modem. Often the Internet provider will make a list of compatible modems available, though these lists are rarely exhaustive. Online manuals for modems and technical specifications will also commonly list which Internet Service Providers the modem supports.

Touch Screen Monitors

Touch screen monitors are no longer confined to bar video games as novelty items. Today, they can be found in many stores as part of cash registers, in car dashboards and on many portable computers. With the growing popularity of touch screen enabled Palm Pilots and other PDAs, many people even have one in his or her pocket at all times.

The benefits of such technology are obvious. Rather than lugging along extra input devices such as a mouse or a keyboard, the user need only his finger to manipulate the chosen device. But it's not just mobile devices that benefit from this type of input. All kinds of devices can be equipped, including TV and computer monitors, LCD screens, and the older CRT computer monitors. As a result, a bartender can press on a screen to ring up drinks on a busy night rather than type in a price, a nurse can input patient information with one hand. Truly, the possibilities with touch screen monitors are endless.

Touch screen monitors usually come in three varieties that enable it to recognize a person's touch. These are resistive, capacitive and surface acoustic wave. The resistive type works by having two panels with a thin space between them. When the user presses the screen, the two panels touch at that point, and the exact coordinates are then registered with the computer.

A capacitive system runs a small electrical charge throughout the touch screen. When the user touches the chosen area, some of the electrical charge is distributed to the finger, lessening the charge at that location. The coordinates are again recorded and sent to the computer. This type of touch screen produces a clearer picture because it transmits more light and doesn't require two panels.

Finally, the surface acoustic wave system is the best, and results in the clearest picture. Transducers are used to send electrical signals across the screen, and if a user touches the screen, they can determine where based on how the electrical signal is received from one transducer to the other.

Since the capacitive system must have a finger to absorb electricity, most non-living objects won't register as a touch. Resistive and surface acoustic wave systems on the other hand react to just about any form of pressure. Each has its different advantages as a result, and manufacturers will only find new ways to make use of them.

Loudspeaker

A loudspeaker is simply a device that converts electrical energy into sound that is amplified so that it can be heard from a greater distance than the original sound would allow. There is no difference in usage of the terms speaker and loudspeaker and both are often used interchangeably. Some loudspeakers are capable of producing sounds over a wide range of frequencies and some are only made to reproduce certain frequencies.

While it may seem as though it is more desirable for a loudspeaker to transmit over the widest range of frequencies possible, there are advantages to those which have a limited range. Due to the size of the system needed to reproduce the broad spectrum of frequencies well, it may be harder to find a compact loudspeaker that can adequately handle the task. Therefore, many speakers trying to do all frequencies may do a substandard job of sound reproduction.

Having multiple speakers, with some specializing in different ranges of sound frequencies, offers some advantages. A loudspeaker designed to handle mid-range and upper-range sounds may be good for reproducing human voices and certain types of music. However, other speakers, such as the woofer and subwoofer, are designed to produce sounds of lower octaves.

A loudspeaker is classified as a woofer if it is meant to reproduce lower octaves of sound. A subwoofer is a loudspeaker that is meant to produce the lowest two to three octaves of sound. The subwoofer often looks like a box and is most likely the speaker prone to the most noticeable vibrations.

One of the most common uses of loudspeakers in the home environment is as home theater speakers. These speakers often are synchronized so they produce a surround sound effect and are often referred to as surround speakers. This is especially useful when watching movies, where the audio is often meant to be played on a surround sound system.

The quality of the loudspeaker greatly depends on the weight, and therefore the size, of the magnet inside the speaker. The larger the magnet, the more powerful the speaker will be. The weight of the magnet should be listed on the specifications of any good loudspeakers. However, it should be noted that some weigh the entire magnet system and not just the magnet itself. This could affect the power and quality of the speaker and deceive some into buying something other than what they thought they were purchasing

Concrete Mixer

A concrete mixer is a powered device that mixes cement with water and aggregate, such as sand or pea gravel, to make concrete. Concrete mixers range from the very large commercial mixing truck to the smaller, portable concrete mixer sometimes called a “mini mixer”. A concrete mixer is comprised primarily of a motor, a rotating drum, and often a chute. Inside the drum, the materials used to make concrete spin around, mixing together evenly and remaining soft for application and forming.

A large commercial concrete mixer truck is used for mixing and transporting large volumes of concrete for use on a building site. For smaller volumes of concrete, typically up to two cubic yards (1.83 cubic meters), a portable concrete mixer is sufficient. A portable concrete mixer is typically powered by electricity and sits on a base with wheels for easier transport. The rotating drum can be tilted down so that mixed concrete can be poured into a wheelbarrow.

For homeowners attempting small concrete projects such as a patio, sidewalk repair, or small slab, a portable concrete mixer is essential to maximize efficiency. A concrete mixer does not keep concrete ready for application indefinitely, so it is important to have an understanding of how much concrete you can pour and finish within a specific time frame. Different types of concrete set faster than others, so check the manufacturer’s directions.

Larger projects, such as a driveway or basketball court, may require calling a commercial truck. Commercial concrete mixers require access to within a fairly close distance of the project. In-ground swimming pools are an example of a large-scale project requiring direct access by a truck.

Understand that calling a concrete company only secures delivery of the concrete. Pricing is a flat rate per cubic yard ordered and the truck will remain on site only for a specified period of time. Large projects may require professional concrete finishers to accomplish the task within the time frame provided. Before calling a concrete company, be sure to have finishers on site and ready to pour, and don’t forget to obtain any permits necessary in your area.

Coffee Maker

A coffee maker is an electric countertop appliance that brews hot coffee automatically. It consists of a hot plate, a carafe or glass coffee pot, filter basket, and water reservoir.

A coffee maker is a very simple, low-tech, yet efficient machine. A heating element circles the hot plate at the bottom of the maker. Wrapped in this heating element is a hollow aluminum tube. When water is added to the reservoir, a small hole in the bottom of the container feeds a plastic hose that leads down to one end of the aluminum tube. Once the coffee maker is switched on, the heating element gets hot very quickly. Sensors cycle the element on and off to keep it 195-205 degrees Fahrenheit (90-96 Celsius). Water sitting in the aluminum tube boils and the turbulence creates bubbles that rise though the opposite end of the tube, traveling up an exit hose (making room for more water to enter the heating element). Hot water riding on these rising bubbles creates upward lift that carries a small stream of boiling water to the top of the coffee maker. Here the exit hose terminates on to a drip plate. The drip plate distributes the boiling water evenly to fall through to the coffee grounds below in the filter basket. Hence, the drip coffee maker fills the carafe with freshly brewed java.

If you buy coffee beans whole you can use a coffee grinder to prepare them. It is best to grind the beans just prior to brewing. A drip coffee maker uses medium to coarsely ground coffee, while finely ground coffee is used for making espresso. Note that espresso cannot be brewed in a drip coffee maker, but is made in an espresso machine.

Most coffee makers have a timer allowing them to turn on automatically. Some people prefer to prepare their coffee maker at night, setting the timer so they can wake to freshly made coffee in the morning. Though this is convenient, connoisseurs would not only object to grinding the coffee beans so many hours in advance, but would also point out that once the coffee is brewed it should be taken off the hot plate. Continued exposure to heat will bring out harsher flavors including bitterness.

Some coffee makers use steel filters, others use paper filters. Steel filters will allow more oils to pass, making coffee that is headier and has more body. Paper filters create cleaner, lighter coffee.

Experts say evidence suggests coffee Arabica originated in Ethiopia and has been cultivated for about 1500 years. Though coffee is brewed many different ways all over the world, today the coffee maker is by far the most popular way to brew a cup of Joe.

Wire Rope

Wire rope is a heavy, tensile, strong, weather-resistant hoisting cable made from many small metal filaments wrapped and braided together. You can get a lot of strength and flexibility out of wire rope because the separate wires equalize pressure throughout the bunch and work well with pulleys. We can find wire rope on a modern farm, a fishing boat, and an international dock.

Usually wire rope is comprised of steel strands arranged in an array around a central core. This design allows the entire wire to hold a lot of weight and still stay ductile. The individual filaments are wrapped into a bunch called a strand. Several of these strands, perhaps six or nine, are then arranged into an even larger bunch called a wire surrounding a central core, the sheath.

Wire rope can be made from steel or iron. For outdoor use, many kinds of wire rope are galvanized so they won't rust through corrosion. Wire that hasn't been galvanized is called "bright." Other types are available with alloys that add various advantages. Wire rope usually can be maintained with cleaning and lubricating to make sure it remains compatible and safe with rigging hardware.

Some characteristics of wire rope are diameter, breaking strength, resistance to corrosion, difficulty of flattening or crushing, ability to be bent and average lifespan. For each application of pulleys, chains, and weights, an industrial engineer needs to determine the correct type of wire rope. Only that size, weight, and braid of rope can be used to ensure that it won't fray or snap.

People use wire rope to protect forests, unload imported goods, or provide raw food. Farmers use wire rope to lift entire grain silos. Firefighters that take water out of lakes for dropping onto flames must tie the scoop to the helicopter. In major ports, both the docking ships and the vehicles on the ground need wire rope in rigging to move giant pallets.

The most important aspect of wire rope is how it will function under the stress of each application. In many uses, it supports giant, heavy objects, and if it fails, lives could be in danger. Always know the breaking strength of your wire rope and, unless you are a professional, don't use it in a way that could potentially injure someone.

Beaded Curtain

Beaded curtains are dividers or curtains that are composed of multiple strings of beads placed in close proximity to create the general look of a drape or curtain. A beaded curtain is sometimes used to divide a room into two separate areas, or to provide a decorating accent that helps to highlight some feature of the space. Curtain beads can be composed from a wide range of materials, including wood, bamboo, or various types of plastic.

One of the more common examples of a beaded curtain is the beaded door curtain. Sometimes employed as a way to limit the visual access to another room, beaded door curtains have the advantage of allowing verbal communications to continue while providing no barrier to slow down free movement between the connected rooms. For example, a beaded curtain hung in the doorway separating a den from a kitchen makes it possible to continue a conversation with the cook without exposing the condition of the kitchen to anyone sitting in the den. In addition, the beaded curtain allows the cook to emerge with platters of food or drink with ease, without any need to stop and open or close a door.

Another application for the beaded curtain is as a window dressing accent. When draperies are considered too heavy for the general décor, the beaded curtain may provide the ideal solution. The colors of the beads help to dress the window area while still allowing light to come into the space. When paired with a simple cornice board or perhaps hanging plants to anchor the area, the beaded curtains may serve as a focal point in the room.

Using beaded curtains as room dividers is also a quick and easy means of giving an open space definition for more than one function. A large room, such as those found in loft apartments, can make use of a beaded curtain to establish specific living and dining areas. A beaded curtain may also provide an inexpensive and decorative way to separate the sleeping area from other areas of the loft as well. The curtains can easily be suspended from the rafters using simple “S” hooks and dowels to hold the rows of beads in place.

While the beaded curtain may not be compatible with some types of room décor, there are many instances where the look and function of the curtains is ideal for the space. Because of the wide range of colors and textures available with the beads, it is possible to construct a beaded curtain that is tailored for a specific need. 

Pocket Watch

A pocket watch is a timepiece meant to be carried in the pocket, rather than worn on the wrist. Pocket watches predate wristwatches by about 400 years, the first invented in 1510 Nuremberg, Germany by Peter Henlein.

Despite its long history, the absence of exacting mass manufacturing meant the accuracy of pocket watches varied greatly from watchmaker to watchmaker, even into the 19th century. Dire results were to be demonstrated in the great train wreck of 1891 in Kipton, Ohio. Here the pocket watch of an engineer stopped for 4 minutes, leading to two trains colliding on the same track. The only way to avoid further disasters was for the American Railway Association to set a high quality standard for pocket watches used in the railway system. Ergo, a pocket watch that met this standard held the distinction of being Railroad Approved.

A pocket watch can have a visible bezel, or it can be encased, usually in a metallic cover of silver or gold. The case might be finely polished, engraved, include a relief, or other artistic design, such as the once-popular train. The pocket watch case has a small spring latch. When activated, the bezel's cover flips open, remaining latched at the left bottom portion of the case for easy closure.

A pocket watch is used with a gold or silver watch chain. The type of chain depends on where the pocket watch will be worn: in a vest pocket or pants pocket. The T-bar chain slips through a vest buttonhole; the spring ring chain attaches to a belt loop; and they belt clip chain attaches to the belt itself. A shorter-style chain features a decorative fob on the end, and is meant to simply hang from the pocket freely. In all cases, the other end of the chain attaches to a small ring at the top of the pocket watch, for easy retrieval.

By the 19th century the pocket watch was a status symbol of high society. This popularity continued into the 20th century when pocket watches became fashion statements worn with zoot suits. And while the wristwatch gained popularity from its necessity on the battlefield during WWI to coordinate troop maneuvers, (wristwatches were provided to the troops by the army), and the pocket watch was still the accessory to wear with three-piece suits of the 1950s. Eventually, however, wristwatches replaced the pervasive popularity of the pocket watch.

Today there is a resurgence of interest in the ever stylish, ever classy timepiece that has been faithfully ticking away the hours for nearly 500 years. If you are considering a pocket watch for yourself or as a gift, they are sold wherever watches are sold, and they are available in every price range.

Voltage Regulators

Voltage regulators are components that maintain a consistent voltage output. Electronic components are often made to accept only a low maximum voltage, and can be badly damaged by a power surge. Likewise, a low voltage can fail to provide enough power for the component. Voltage regulators are often responsible for maintaining a voltage within the range that the electronic component can safely accept.

A computer is one example of an electronic device that requires voltage regulators. Voltage regulators are responsible for transmitting the voltage generated by the computer's power supply in a low-voltage flow that won't damage the microprocessor. A computer may require one or two voltage regulators, depending on the system; some computers use special "voltage ID programmable" voltage regulators, which interface with the microprocessor to ensure a specific voltage level.

Cars also use voltage regulators in the system that maintains the battery's charge. Voltage regulators are usually part of the car's alternator, although many cars, particularly older cars and modern American models, have exterior voltage regulators. Alternators or generators are used to generate power, which is fed into the car's battery in order to maintain a full charge. The power generated by the car's charging system is also used to run the car's electrical systems, such as headlights, radio, power windows and locks, and ventilation systems.

An alternator or generator has a pulley on one side that is turned by one of the engine's drive belts; the force of the engine is therefore used to run the alternator or generator. Because the engine's speed varies during acceleration and shifting gears, voltage regulators are necessary to control the output produced by the alternator or generator. An excessively high voltage output, caused by the engine's higher speeds if the alternator or generator is unregulated, could send a surge through the system, overcharging the battery and damaging the car's electrical systems. A very low voltage output will fail to produce enough power to maintain the battery's charge and run the car's electronic systems, creating a load on the battery and potentially reducing the battery's life.

When voltage regulators stop working, they need to be replaced. Voltage regulators for computers or other basic household electronics are available through dealers that specialize in electronics. For cars, voltage regulators are available from the dealership or aftermarket parts stores. Some cars may have external voltage regulators, in which case the voltage regulator may be purchased separately and easily replaced. However, most cars' voltage regulators are located inside the alternator, requiring the owner to either buy a new alternator or rebuild the existing alternator with a new voltage regulator.

Alternator

An alternator is part of the charging system of your car that produces electricity for many devices. A type of generator, the alternator transforms mechanical energy into electrical energy. Although your car's battery supplies some electricity, most of the electrical mechanisms within the vehicle, require the alternator's steady stream of power.

Alternating current (rather than direct current) gives the alternator its name, because this is the type of electricity it creates. It's mainly a mechanical device, concealing a pulley, wheels, brushes and wires, which hooks to the crankshaft and runs to the battery. This way, the gasoline powers the engine to turn the crankshaft, which in turn connects to the alternator. The alternator converts that motion into current whenever the car is running. The resulting electricity operates the cooling fan, headlights, windshield wipers, radio, defogger, and air conditioning.

To be more specific, an alternator is very efficient at producing a constant, high voltage, even when the car is idle, because of how it works. The belt (from the crankshaft) connects to a pulley system, called the rotor, such that when the belt is turning, it moves magnets across a special surface, called a conductor. Moving magnets, in the stator, generate an electrostatic field, otherwise known as electricity. This alternating current is controlled by a voltage regulator to keep the voltage steady. Another part, called the diodes, convert alternating current into direct current that flows on to the battery and other components.

Even if your alternator dies or malfunctions, your car will run for a while directly off of the battery, until all the battery's power is sapped. Therefore, it is hard to tell when your alternator has problems. Sometimes a harsh noise, or intermittent headlights, will give it away. Check to make sure the belts on the alternator are not cracked, or improperly tightened, before you replace the entire thing. A rebuilt alternator can be a reliable, but less expensive, option if you need it repaired

Cell Phone Charger

A cell phone charger is a device used to recharge the battery in a mobile phone unit. Often, a basic cell phone charger comes with the cell phone when it is purchased. In some cases, additional chargers may be purchased that have added features.

There are many different types of cell phone chargers to choose from. Among the most popular are wall chargers, car chargers, travel chargers, rapid chargers and instant chargers. Many mobile phone owners may own one or more of these other types of chargers, depending on situations they may find themselves in.

The wall charger is the most common type of cell phone charger. It has a standard plug designed to fit the outlets in the country in which it was sold. In some cases, this cell phone charger may come with some added features, such as a docking station for the phone. However, this may actually decrease the phone’s functionality, as it cannot be used while charging. The travel charger is usually very similar to the wall charger but is usually less bulky and may include prongs that fold down for easier travel. In some cases, the travel charger has replaced the wall charger as the standard one included with the phone.

The car charger is another very popular option. This cell phone charger has an adapter that allows it to be plugged into a vehicle’s DC port, commonly known as a cigarette lighter. It is especially useful for those who do a substantial amount of traveling and need constant access to their mobile phones.

A rapid charger looks very much like a wall charger, but is a more powerful cell phone charger, able to charge phones in just a fraction of the time it would normally take. For most models, charging a phone takes two to three hours. Rapid chargers advertise the ability to charge the phone in less than an hour, in many cases. However, consumers should be aware that some rapid chargers can shorten the effective life of the battery.

Instant chargers are really one-time, non-replaceable batteries. They usually do not replace the installed battery, but rather connect to the phone just like a normal charger would. These are useful in emergency situations when a cell phone battery is low or dead. The job of this type of cell phone charger is simply to transfer current from one battery to the next.

When buying a cell phone charger, it is important to understand that just because it works with your brand of phone; it may not work with your model. Be sure to cross reference the model number on the packaging to your own phone. In many packages, the connecting portion of the charger to the phone is outside the rest of the packaging, giving the consumer a chance to test the connection, if they have their cell phone with them. This is the most foolproof way of making sure you have the right connection.

Telestereoscope

A telestereoscope is an optical device which is designed to present a three dimensional view of a distant scene, sometimes called a binocular telescope because it offers a view of distant objects through both eyes. In addition to use in optometry, telestereoscope can also be used in astronomy observatories, and at least one telestereoscope has appeared in an art installation. The basic mechanics of the device are the same in all instances, however. A telestereoscope uses two viewing fields, rather than just one, to provide a three dimensional image to the person looking through it. The experience of using a telestereoscope is similar to that of using a three dimensional viewer, or looking at a stereoscopic photograph.

The groundwork for the telestereoscope was laid by Hermann von Helmholtz, an Austrian scientist who lived between1821-1894. He had a background in medicine and physics, and spent a great deal of time pursuing the study of optics. He invented the ophthalmoscope, a medical instrument which is used to examine the inside of the human eye. He also speculated on color vision, how humans see motion, and depth perception. The telestereoscope was an optical device which he used to further his research.

A telestereoscope takes advantage of basic human optics. The human eye interprets images with the understanding that the distance between the eyes does not change. When someone looks at things in daily life, he or she is seeing a stereoscopic, or three dimensional, image, and the eyes create a sense of depth given the two images that they are receiving. Depth perception is used as a visual cue to determine how far away from something someone is. In the case of a telestereoscope, the viewer looks through periscopes which are spaced further apart than normal human eyes. As the eyes struggle to interpret the images they are seeing, things which are far away suddenly seem very close, and the image appears almost hyper-real, as the depth is distorted.

In optics, a telestereoscope is frequently used in tests of depth perception, usually in a version with does not distort vision so much. Scientific studies of optic phenomena have also used telestereoscope. In astronomy observation, a telestereoscope can be used to create a rich and lush image of a very distant point, although a telestereoscope is not a piece of standard observatory equipment, due to the cost. As an art installation, a telestereoscope can be used to make a statement about the world around the viewer, or to challenge conventional optical reality.

ELECTRON MICROSCOPE

An electron microscope is a type of microscope that uses electrons rather than photons — as a conventional light microscope does — for imaging. Because electrons have a much smaller wavelength than photons, they provide much greater magnification. Electrons are the tiny “satellites” that orbit the atomic nucleus and carry electric charge – these particles are so small that in physics they are often modeled as points. Yet light waves are much larger, with a wavelength of around 500 nanometers for the color green, for instance.

The best optical microscopes only offer about 2000X magnification of a sample, whereas some electron microscopes can magnify a sample by 50 million times; in contrast, 2 million times is more typical. This works out to a resolution limit of about 0.1 nanometers, allowing the observation of individual atoms on a surface. The electron microscope was invented in 1931, when the first working prototype was built by Ernst Ruska and Max Knoll. Ruska was eventually awarded the Nobel Prize in Physics (1986) for his achievement.

There are four types of electron microscopes, the first two being the most common: the transmission electron microscope (TEM), scanning electron microscope (SEM), reflection electron microscope (REM), and the scanning transmission electron microscope (STEM).

The transmission electron microscope is the electron microscope as it was originally invented. Using a sample that is semi-transparent to electrons, an electron beam is fired directly through the sample. A receiver on the other side measures the density of electrons at each individual point and compiles them into a grayscale image. This is the image of the sample.

A scanning electron microscope has somewhat less resolution than a TEM, but is still the most popular variety of electron microscope. Like its name implies, a scanning electron microscope scans an electron beam across the sample. Instead of analyzing the original beam for information about the makeup of the sample, sensors pick up secondary electrons released from the surface of the sample via excitation from the primary beam. This sacrifices some resolution for a 3D image of the sample. This is more than worth the trade off, and SEMs are accordingly the most popular electron microscopes.

Most scanning electron microscopes are very costly to buy and maintain. They require a stable high-voltage electricity source, a vacuum pump, and cooling coils. Samples have to be prepared, usually by coating them with a thin layer of conductive material such as gold.

ACCOUNTING

An accountant is an individual who performs accounting tasks for individuals or companies. The exact material that an accountant handles varies depending on the size of the company and the accountant's specialization, but generally includes financial records, taxes, and responsibility for the issuing of financial reports. An accountant is one of the primary figures in a business that he or she works for, whether it is a multinational corporation or a small family owned business. Requirements to become an accountant vary upon specialization and nation, but generally include certification through a professional agency and a basic college degree in accounting and finance.

In a small firm, an accountant may be responsible for keeping all financial records. These records include payroll information, accounts payable, accounts receivable, retail sales, and information regarding investments held by the company. These accounts are kept organized in ledgers which are used to assets the financial health of a company. Ledgers are always kept up to date, and may be consulted by managers and high ranking members of a company when they are making major business decisions.

In larger firms, accountants also perform internal audits, to ensure that the financial records of the company are accurate. Because of bias concerns, an internal audit cannot be handled by an accountant who regularly handles the material concerned, and many companies hire outside accounting firms to perform audits. When this is the case, the company should not be contracted to handle any of the company's other financial material, as this may represent a conflict of interest.

In most cases, an accountant will choose to specialize in a particular field such as audits, book keeping, or taxes. In other instances, an accountant may acquire a wide range of skills to better serve his or her clients. This is common with certified public accountants who handle the books for several small businesses at once. In both instances, the accountant must have strong math skills, as well as an education in accounting.

Depending on the type of accounting being performed, certification by the state may be required. State certification is usually required for accountants who perform audits and other sensitive accounting tasks, while it is not as vitally necessary for accounting clerks who work under certified accountants. Commonly, an accountant is also a member of a professional organization of accountants, and takes advantage of meetings and seminars to keep up with advances in the field.

STOCK BROKER

Looking for a stock broker? Prepare to be a little confused. There are full-service stock brokers and discount stock brokers, representing a myriad of brokerage firms. There are execution only, advisory and discretionary dealing stock brokers. You can interact with your stock broker online or on the phone, and you can either bring your own plan to the table or rely completely on the broker's expertise.

While the term "broker" might make some investors a bit uncomfortable in these stark economic times, the word actually means "one who acts as an agent for another." In the case of a stock broker, this can be done on various levels. An "execution only" arrangement puts most of the burden on the client, who calls the broker and simply provides instructions on what to buy or sell. Advisory dealing still leaves the decision with the client, but the stock broker may offer background information and suggestions. Finally, with a "discretionary" relationship, the stock broker is given free rein to use his or her own judgment.

The stock market is, at its core, a gamble. What the stock broker does is to bet your money that the price of a certain share of stock will rise beyond what you pay for it -- if not immediately, at least in the long term. A broker may also advise you to sell a certain stock that seems to have peaked, or is rumored to be on the verge of a fall.

A full-service broker might deal with other financial entities, such as annuities and bonds, as well as stocks. At the other end of the spectrum is the discount broker, whose relationship is generally conducted through execution only. The pool of knowledge required to be an effective stock broker is immense. Not only must the broker be on intimate terms with the rules and quirks of the market, but he or she must also be able to process information about various companies with an eye toward whether that stock is likely to go up or down.

In order to reach that position of authority, a prospective broker must pass two comprehensive examinations. Almost all of them work for brokerage houses, and they are paid in various ways. Some work on commission from the customer, some work on a fixed salary, and some combine both.

What kind of broker to choose depends on a number of factors? If you are a person who enjoys playing the market and relishes the thrill of the gamble, a discount broker might be the way to go. If you are hoping to grow your retirement nest egg a little without taking a great many risks, you would probably want to turn over more responsibility to your broker. Obviously, the more input and services a broker offers, the higher the price or commission.

VENDOR FINANCING

Vendor financing is a loan arrangement that takes place between a company and a vendor that supplies a large amount of product to the company. This arrangement is different from extending a credit line, in that vendor financing involves the establishment of a specific amount that will be loaned, and with terms and conditions regarding the repayment of the loan within a specified period of time. Vendor financing is not uncommon in situations where there is a strong working relationship between the customer and the vendor.

Vendors may choose to extend an offer of vendor financing as a means of increasing the sales of the company. The extension of the loan to a valued customer helps to make the bottom line look very good for the periods in which the loan amount is used to make purchases. At the same time, vendor financing will involve some type of interest rate on the loans. This means that the vendor also creates a revenue stream of interest income as well.

For the customer, the use of vendor financing may be a way to obtain products that are necessary to the operation, but are difficult to obtain due to current issues with cash flow. When this is the case, the offer of financing by a vendor is often very welcome. However, the customer should accept the offer only after investigating other means of funding the purchases. Vendor financing often involves a rate of interest that is higher than on most business loans. There is also the chance that going with vendor financing will increase the risk profile for the company, depending on the amount and terms of the loan.

In some cases, the vendor may choose to waive any type of payments on the outstanding balance of the vendor financing. Instead, the vendor may choose to accept an interest in the company instead. While this is rarely a controlling interest, it is important that the customer consider this option with great care before accepting the offer.