The devices, which are becoming popularly known as netbooks, or my favorite term, "laptots," have caught on because they offer people a mobile, easy way to wirelessly access the Web.

They come with 7-inch to 10-inch LCD screens and are about half to two-thirds the size of a mainstream laptop. They weigh around 1 kilogram (2.2 lbs) each, carry batteries that last up to 8 hours and generally cost between US$199 and $699.

I've written several netbook reviews and after some consideration, offer these tips for your first netbook.

1. Know what you want to use it for and how much you're willing to spend.

This is a cliche in reviews and doesn't tell you much but it's actually very important. What do you want this for? Do you want a lightweight device for easy Internet access? Or are you really looking for a full-featured laptop computer? Don't buy a netbook if you're really looking for a laptop, it would be a mistake.

To ensure longer battery life, some key components on a netbook, such as the microprocessor, are far less powerful than common laptops. That's why they're good for surfing the Internet, doing homework on a word processing program, working on spreadsheets or for presentations and other Office-like work.

Anyone looking for a gaming laptop or one for video-editing or other multimedia work should shop for true laptops, not netbooks.

2. Buy a netbook with an 8.9-inch screen or larger.

I tried out an Eee PC with a 7-inch screen and the annoying part is not being able to see an entire Web page because the screen is too small.

That's less of a problem on the slightly larger-sized screens and in the 8.9-inch screen size, the weight and size of the netbook is nearly the same as devices with 7-inch screens.

3. Make sure you get a 6-cell battery for your netbook, although you may have to pay $50 more and the device will weigh more.

Most companies are offering netbooks with 3-cell batteries as the standard, but that doesn't offer a whole lot of run time, just 2 to 3 hours. A 6-cell battery doubles that, and in some devices designed around a 6-cell battery, such as Asustek Computer's Eee PC 1000 and Eee PC 901, you can get up to 8 hours.

In a mobile device, battery life is vital. You don't want to always be looking around for plugs, nor fighting over the last one.

Most vendors are now following Asustek's lead with 6-cell batteries. Micro-Star International recently announced a line of Wind netbooks with 6-cell batteries, and Acer recently put out a formal version of its Aspire one with a 6-cell battery, and larger HDD to boot.

Vendors generally offer 6-cell batteries for all models. But most devices come standard with a 3-cell or 4-cell battery, so if you want a 6-cell then you have to ask for it, and expect to pay a bit more.

Another benefit of the larger battery is that it props up the back of the device, putting it on a slight angle that makes typing easier. Keypads on netbooks are smaller than normal keypads, and comfortable typing was one area I was not willing to compromise on.

4. Try out the keypad and make sure it's right for you.

None of the devices I tested had a better typing pad on a cheaper netbook than Intel's ClassMate PC, which has a keypad far smaller than the Eee PC 1000. Keys on the ClassMate PC's keyboard are raised and there is a lot of space between them, making them easy to find by touch.

By contrast, the Eee PCs, Wind and Elitegroup Computer Systems' G10IL designed their keypads with flat keys and little or no space between keys because, I was told by Elitegroup staff, it makes them look nice.

The trouble is, it also makes typing more difficult.

I really liked the keypads on Acer's Aspire one and Everex's CloudBook Max, but the best keypad was on Hewlett-Packard's Mini-Note.

5. Software: see what it comes with and consider trying the Linux OS.

There are two lessons on software.

First, some vendors have skimped on including software in their netbooks on the pretense that users can download a lot of free software on the Internet. That's true, but it's a bogus excuse. Who wants to spend time downloading when many netbook makers have added lots of software so users can play with their new netbook right away?

Asustek included a lot of useful software on its Eee PCs 1000, 1000H and 901, as has Acer, which also added a nice opening screen that boots up in just 12 seconds.

Second, it may be time to the give the Linux OS a try.

The Acer opening screen I just referred to is based on Linux, and the Aspire one comes with the Linpus Linux Lite OS, which is very user friendly. I've used Windows for most of my life but switching to Linux to try out the Aspire one was smooth and easy.

Most of the netbooks I tested with Linux OSs booted up far faster than Windows XP or Windows Vista (I would not buy a netbook with Vista, it's just too slow).

There are also free Linux-based word processing programs, spreadsheets etc. available on the Internet such as Open Office, Google Pack, which includes Sun's StarOffice or Web-based software such as Google Apps.

Of course, it would be nice to see a Web site devoted to netbooks, with software specifically designed for low-power devices and smaller screens. Netbookdownload.com, anyone?

6. Price: if it costs more than $500, start looking at a regular notebook computer.

Companies have started promoting a wide range of netbooks at ever higher prices, but once you pass $500, netbooks start to compete with laptops, and a laptop will almost always give you more value for your money in that case.

Laptop computers have far more powerful microprocessors and other components than netbooks, and sport DVD drives. There are no DVD drives on netbooks.

If size and weight are your main concerns, there are plenty of small, full-featured laptops, including the Sony Vaio VGN-TZ340, Lenovo Ideapad U110-23042BU, and of course, Apple's lightweight MacBook Air.

7. Look around at what's available.

There were a lot of devices that impressed me and that are worth considering.

Giga-byte's M912, is the netbook that has by far the coolest technology on board with its touchscreen. The screen can also swivel around so you can show someone else what you're working on or looking at on the Net.

But I was quoted a price of NT$19,900 (US$632) for the device, and since I'm not really sure how much I'd use the touchscreen, I figured it wasn't right for me.

I almost decided on one of the netbooks with the bigger, 10-inch screens. My top choices were Asustek's Eee PC 1000 with the Xandros Linux OS and a 40G-byte solid state drive (SSD) for storage and 6-cell battery, or Micro-Star International's Wind with a 6-cell battery.

Both devices are very nice to use but were a little bigger and more expensive than what I was looking for. Size is important to consider in terms of weight. Ten inch screens, hard disk drives (HDDs) and 6-cell batteries add a lot of extra weight to a netbook.

All of the netbooks I tried out include wireless Internet access through Wi-Fi 802.11b/g, but only Asustek's Eee PCs 1000, 1000H and 901 offered speedier 802.11b/g/n as of this writing.

The CloudBook Max will be sold with subscriptions for WiMax wireless networking, and some netbooks will also be sold with built-in 3G modules so mobile phone service providers can offer them with 3G (third generation telecommunications) contracts, so people can access the Internet from anywhere on their mobile phone network.

People can also buy add-on 3G (third generation telephony) or WiMax cards for any netbook.

8. And finally, the best netbook available is....

I tested several different netbooks and published reviews on them all, and after trying out some pretty cool devices, I decided to buy the one that's right for me: Acer's Aspire one.

Based on the criteria above, here's why:

I already have a laptop PC, so I don't need a powerful netbook. I just wanted a smaller, lighter device easier to carry around that I can use to surf the Web and write outside my office.

The Aspire one comes with an 8.9-inch screen and a 3-cell battery, standard, but I will pay a little more for a 6-cell battery. I get stranded in airports sometimes, often take trains, and simply like to sip my coffee very slowly. I need a long lasting battery.

The keypad on the device is quite comfortable, and the software it comes with is easy to use, especially the Linpus Linux Lite OS.

The price sealed my decision.

Last Friday, Acer slashed prices on three Aspire one models in the U.S., to US$399 for an Aspire one with Windows XP, a 160G-byte HDD (hard disk drive) and 6-cell battery. An Aspire one with Windows XP, a 120G-byte HDD and 3-cell battery costs just $349, and a similar device running on Linpus Linux Lite is just $329.

I plan to buy the $329 Linux-based Aspire one, which has an 8.9-inch screen, a 1.6GHz Intel Atom microprocessor, 512M bytes of DRAM and 8G bytes of flash memory storage and a 3-cell battery. I'll add more DRAM and buy an additional flash card, as well as trade up to a 6-cell battery, which will likely raise the price to around $420, in all.

|

While the Chevy Volt continues to mature towards production, other four door plug-in electric hybrid vehicles continue to emerge. Kia Motors debuted their sleek Ray concept car yesterday at the Chicago Auto Show. The Ray is a four-seat compact sedan based on the Kia Forte platform powered by a direct injection four cylinder engine with a continuously variable transmission. On the electrical side the concept draws power from a lithium ion polymer battery pack which spins a 78-kilowatt electric motor. What this all means is that the Ray isn’t meant to be a high performance vehicle but Kia is aiming for efficiency and range. Kia speculates the car would get 202.3 mpg in electric only mode and 77.6 mpg running as a hybrid. Electric power provides 50 miles of travel and the overall range is estimated to be 746 miles.

What will likely capture a lot of attention is the Ray’s styling and design. The concept was produced at Kia’s California design studio under the direction of chief design officer, Peter Schreyer.

It is important to imagine what people will want in the future from a green perspective early in the design process, because people want to reduce their carbon footprint without driving carbon copies. Being green doesn’t have to be an obvious statement anymore and the Kia Ray exemplifies a viable blend of modern, eco-minded features for today’s environmentally conscious consumers.

Likely learning a lesson from the design development the Volt went through, engineers and designers at Kia sought creative ways to make the Ray aerodynamically efficient to boost the range. This had obvious implications for the exterior styling so inspiration came from looking at aircraft. Referencing a wing, the car’s side profile tapers tapers towards the rear, reducing drag. The exterior glass incorporates new “cool car” technologies like nano-laminate films and integrated solar cells to keep the interior cool and reduce the need for air-conditioning. The transparent roof contains hexagonal solar cells that provide power to interior fans to keep the car cool.

The Ray’s interior is comprised of eco-friendly recycled materials and the design aims to create a light and airy feel. Front and rear seats, mounted on side sills, create a floating effect with hollowed out elastomeric materials to support body weight, also made of lightweight composite materials. The flooring is 100% wool, a renewable resource. The Ray features the new GreenEdge Infinity audio system with speakers that use less power and components that save weight.

|

1. Cessna 172 - Made in United States - More than 43,000 Planes till now - Still in production. Was also built under license in France (The Cessna 172 Skyhawk is a four-seat, single-engine, high-wing fixed-wing aircraft. First flown in 1955 and still in production, more Cessna 172s have been built than any other aircraft)
   Military operators
   A variant of the 172, the T-41 Mescalero is used as a trainer with the United States Air Force and Army. Due to its high-wing design, stability at low airspeeds and relatively low stall speed, the 172 is used for search operations and is the primary platform for the Civil Air Patrol's operations. In addition, the United States Border Patrol uses a fleet of 172s for aerial surveillance along the Mexican-American border.
   
2. Polikarpov - Made In Soviet Union - More than 40,000 planes til 1959 - Most produced biplane
   The Polikarpov U-2 or Po-2 served as a general-purpose Soviet biplane, nicknamed Kukuruznik , NATO reporting name of "Mule". The reliable, uncomplicated and forgiving aircraft served as a trainer and crop-duster. It is the second most produced aircraft, and the most produced biplane, in the history of aviation.
3. Ilyushin Il-2 - Made In Soviet Union - More than 36,183 planes till 1945 - Most produced combat aircraft.
   The Ilyushin Il-2 Shturmovik (Russian: Ил-2 Штурмовик) was a ground attack aircraft in the Second World War, produced by the Soviet Union in very large numbers. In combination with its successor, the Ilyushin Il-10, a total of 42,330 were built, making it the single most produced military aircraft design in all of aviation history, as well as one of the most produced piloted aircraft in history along with the Cessna 172 and the Polikarpov Po-2. It was a prominent aircraft for tank killing with its accuracy in dive bombing and its 37mm guns penetrating their thin back armor.
4. Messerschmitt Bf 109 - Made in German - More than 35,000 Plane till 56 - Most produced fighter. Also made under license in Romania, Spain, Czechoslovakia, and Switzerland.
   was a German World War II fighter aircraft designed by Willy Messerschmitt in the early 1930s. It was one of the first true modern fighters of the era, including such features as an all-metal monocoque construction, a closed canopy, and retractable landing gear. Having gone through its baptism of fire in the Spanish Civil War, the Bf 109 was still in service at the dawn of the jet age at the end of World War II, during which it was the backbone of the German Luftwaffe fighter force. An inverted Vee-piston engined fighter, the Bf 109 was supplemented, but never completely replaced in service, by the radial engined Focke-Wulf Fw 190 from the end of 1941.
5. Piper Cherokee - Made in United States - More than 32,778 plane till now.
   is a family of light aircraft designed for flight training, air taxi and personal use, built by Piper Aircraft. All members of the PA-28 family are all-metal, unpressurized, four-seat, single-engine piston-powered airplanes with low-mounted wings and tricycle landing gear. All PA-28 aircraft have a single door on the co-pilot side, which is entered by stepping on the wing.
   

|

Theory and construction
A railgun consists of two parallel metal rails (hence the name) connected to an electrical power supply. When a conductive projectile is inserted between the rails (at the end connected to the power supply), it completes the circuit. Electrons flow from the negative terminal of the power supply up the negative rail, across the projectile, and down the positive rail, back to the power supply.

This current makes the railgun behave as an electromagnet, creating a powerful magnetic field in the region of the rails up to the position of the projectile. In accordance with the right-hand rule, the magnetic field circulates around each conductor. Since the current is in opposite direction along each rail, the net magnetic field between the rails (B) is directed vertically. In combination with the current (I) across the projectile, this produces a Lorentz force which accelerates the projectile along the rails. There are also forces acting on the rails attempting to push them apart, but since the rails are mounted firmly, they cannot move. The projectile slides up the rails away from the power supply.

A very large power supply providing, on the order of, one million amperes of current will create a tremendous force on the projectile, accelerating it to a speed of many kilometres per second (km/s). 20 km/s has been achieved with small projectiles explosively injected into the railgun. Although these speeds are possible theoretically, the heat generated from the propulsion of the object is enough to erode the rails rapidly. Such a railgun would require frequent replacement of the rails, or to use a heat resistant material that would be conductive enough to produce the same effect.
Railguns as weapons

Railguns are being researched as weapons with projectiles that do not contain explosives, but are given extremely great velocities: 3,500 m/s (11,500 ft/s, approximately Mach 10 at sea level) or more (for comparison, the M16 rifle has a muzzle speed of 930 m/s, or 3,050 ft/s), which would make their kinetic energy equal or superior to the energy yield of an explosive-filled shell of greater mass. This would allow more ammunition to be carried and eliminate the hazards of carrying explosives in a tank or naval weapons platform. Also, by firing at greater velocities railguns have greater range, less bullet drop and less wind drift, bypassing the inherent cost and physical limitations of conventional firearms–"the limits of gas expansion prohibit launching an unassisted projectile to velocities greater than about 1.5 km/s and ranges of more than 50 miles [80 km] from a practical conventional gun system."

If it were possible to apply the technology as a rapid-fire automatic weapon, a railgun would have further advantages of increased rate of fire. The feed mechanisms of a conventional firearm must move to accommodate the propellant charge as well as the ammunition round, while a railgun would only need to accommodate the projectile. Furthermore, a railgun would not have to extract a spent cartridge case from the breech, meaning that a fresh round could be cycled almost immediately after the previous round has been shot.
Tests
Naval Surface Warfare Center test firing in January 2008, leaving a plume of plasma behind the projectile.

Full-scale models have been built and fired, including a very successful 90 mm bore, 9 MJ kinetic energy gun developed by the US DARPA. Rail and insulator wear problems still need to be solved before railguns can start to replace conventional weapons. Probably the oldest consistently successful system was built by the UK's Defence Research Agency at Dundrennan Range in Kirkcudbright, Scotland. This system has now been operational for over 10 years at an associated flight range for internal, intermediate, external and terminal ballistics, and achieved several mass and velocity records.[

The Yugoslavian MTI (MTI - Military - technology institute) developed, within a project named EDO-0, a rail gun with 7 kJ kinetic energy, in 1985. In 1987 a successor was created, project EDO-1, that used projectile with a mass of 0.7 g and achieved speeds of 3,000 m/s, and with a mass of 1.1 g reached speeds of 2,400 m/s. It used a track length of 0.7 m. According to those working on it, with other modifications it was able to achieve a speed of 4,500 m/s. The aim was to achieve projectile speed of 7,000 m/s. At the time, it was considered a military secret.

The United States military is funding railgun experiments. At the University of Texas at Austin Institute for Advanced Technology, military railguns capable of delivering tungsten armor piercing bullets with kinetic energies of nine megajoules have been developed. MJ is enough energy to deliver 2 kg of projectile at 3 km/s–at that velocity a rod of tungsten or another dense metal could easily penetrate a tank, and potentially pass through it.

The United States Naval Surface Warfare Center Dahlgren Division demonstrated an 8 MJ rail gun firing 3.2 kg projectiles in October 2006 as a prototype of a 64 MJ weapon to be deployed aboard Navy warships. The main problem the Navy has had with implementing a railgun cannon system is that the guns wear out due to the immense heat produced by firing. Such weapons are expected to be powerful enough to do a little more damage than a BGM-109 Tomahawk missile at a fraction of the projectile cost. Since then, BAE Systems has delivered a 32 MJ prototype to the Navy.

Due to the very high muzzle velocity that can be attained with railguns, there is interest in using them to shoot high-speed missiles.[citation needed]

On January 31, 2008 the US Navy tested a railgun that fired a shell at 10.64 MJ with a muzzle velocity of 2,520 m/s. Its expected performance is a muzzle velocity over 5,800 m/s, accurate enough to hit a 5 meter target over 200 nautical miles (370.4 km) away while firing at 10 shots per minute. The power was provided by a new 9-megajoule (MJ) prototype capacitor bank using solid-state switches and high-energy-density capacitors delivered in 2007 and an older 32-MJ pulse power system from the US Army’s Green Farm Electric Gun Research and Development Facility developed in the late 1980’s that was previously refurbished by General Atomics Electromagnetic Systems (EMS) Division. It is expected to be ready between 2020 to 2025

|