top 6 awesome smartphones of january 2015

1. HTC One M8

What to say about the HTC One M8? They often say the second album is the hardest, but the follow up to the all-conquering HTC One takes the best of that phone and yet still re-invents things enough to make it a massive recommendation over the old model.

We love the speed of the camera, the Duo Camera is smart as a tack, the Boomsound upgrade is impressive and the design... well, you have to hold it.

The Snapdragon 801 processor has boosted battery dramatically compared to the 600 of last year, and that means that photos also process much more quickly as well - even the front-facing camera is much better.

Gaming, movies, photography, browsing all work really well, and in a phone that that's easily going to destroy whatever anyone else can design, unless Apple or LG have got some dark sorcery up their sleeves when the iPhone 6 or LG G3 appear later in the year.

2. Sony Xperia Z2

Sony has something of a slump last year, following up the impressive Xperia Z with the lacklustre Xperia Z1 just a few months later.

The camera, which was supposed to be the headline feature, didn't impress as much as we'd hoped, and the screen was still lacking the IPS clout that the Xperia Z Ultra managed - meaning muted colours and poor viewing angles.

Anyway, enough about last year - Sony's back in 2014 and comes with an excellent phone in the shape of the Xperia Z2. Tipped to be the third of the stellar smartphone triumverate, alongside the Samsung Galaxy S5 and HTC One (M8) we were intrigued to see how it shaped up.

And the good news is it's impressive. Really impressive. The industrial design is a little chunky but oozes premium quality in a way that Samsung's plastic shell doesn't, and it's a little more robust than its Galactical and Primary rivals thanks to being IP58 rated.

Great battery life, strong power and a good camera all are present and correct with our new top three phones, but Sony steals second simply by being a great all-rounder.

3. OnePlus One

You've probably never heard of OnePlus... but if you have, you'll know why this unknown brand is suddenly sitting at number three of our list of best smartphones in the world.

The reason is simple: it's a phone that has all the power, specs and functionality of the top dogs, adds in super-customisable software and does it at nearly half the price. We're talking big savings on cost (£229 for the 16GB version and £269 for the 64GB variant) without much in the way of compromise.

In fact, the only things it's really missing are a microSD slot and removable battery, and those are elements more for the purists that absolutely necessary.

If we're being super picky, it's not got the greatest camera set up and the design is a bit... efficient, but at this price point it really doesn't matter. And given the target audience is those that care about raw power over style, it makes sense that this is where the costs could be saved.

4. Samsung Galaxy S5

2014 is turning out to be a stellar year for the prospective smartphone user, as the HTC One (M8) was joined by the Samsung Galaxy S5 in our 'best smartphone' list, and now the Xperia Z2 enters the fray too.

There was a lot of hype around the new Galaxy, and rightly s it's by far the best phone Samsung has ever produced, with a blazing fast core, a strong result in the benchmarks and a larger 5.1-inch screen.

Then there's the fact that with the Qualcomm Snapdragon 801 CPU the Galaxy S5 is one of the best phones on the market when it comes to battery life, besting the already impressive One M8 in the power stakes.

Samsung has also dropped the 'innovation' of the air gestures from last year (well, they are in there but not the main focus) and improved the hardware with a better camera, fingerprint scanner and heart rate monitor too.

5. LG G2

Wait, an LG phone in the top rankings? Believe it people; LG has made a phone that not only impressed us but ran the HTC One very, very close for the top spot in 2013 - and holds a strong place into 2014 too.

We don't know where to start in terms of extolling the virtues of this new handset from the South Korean firm: it's got an insanely good screen, quality camera, the best audio pumping out from its speakers and headphone jack... the list goes on.

We even came to tolerate, then love, the power and volume buttons being placed on the rear. These aren't ideal, but the ability to knock on the screen makes it really easy to interact with this impressive device.

The LG G3 is here now, and is going to blow this out of the water in terms of price and power (it's even got a next-gen QHD screen) but given the lower cost the G2 is still an excellent choice.

6. Google Nexus 5

So we've updated our review with the new phone software, and thankfully things are a lot better now. The battery is improved, the camera a little more stable, and the low cost is still in place.

You already know we like Android 4.4, the clever implementation and the £299 price tag. We love the high power CPU, the quality screen; even the rubberised outer shell.

You can get the LG G2 for around the same price now though, and that offers a far superior camera, better battery life and a huge slew of extra features - it really depends if you're a fan of the stripped-down experience.

Top 9 Gsmes of 2014 for iOS & Android

1. Real Racing 3 (Android, iOS) (Free)



Real Racing 3 may have had a rocky start when it received criticism for the move to free-to-play, but that doesn't eclipse the fact that it's a gorgeous racing game with a fantastic driving experience. Real Racing 3 allows users to take the wheel of a host of real world cars and take them on a spin across gorgeously rendered real-world racetracks. Numerous game modes, from time trials, straight up races and the unique Time Shift Multiplayer mode offer varied challenges to players, with updates continuously adding new content such as new cars, racing events and a pit crew system.

2. Asphalt 8 (Android, iOS) (Free)



Gameloft's Asphalt 8: Airbornealso went the freemium route, delivering stunning graphics and fast-paced arcade racing. Airborne lives up to its name, with numerous ramps and other gameplay elements, encouraging players to take death-defying leaps in order to execute insane aerial stunts. Asphalt 8 features 56 high-performance vehicles from a who's who of automakers, eight seasons, 180 events, and numerous game modes for singleplayer or multiplayer mayhem.

3. GT Racing 2 (Android, iOS) (Free)



Gameloft's GT Racing 2 is a full on broadside against Real Racing's dominance in the realistic driving simulator field. Billed as "The Real Car Experience", GT Racing 2 features more than 71 licensed cars that you can race on 13 tracks. Players can try game modes such as Duels, Knockouts and Overtakes, or participate in classic races across more than a thousand different events, or even try your luck in multiplayer races. Numerous camera modes and a built-in screenshot function let you enjoy the slick graphics and weather effects.

4. CSR Racing (Android, iOS) (Free)



CSR Racing brings its own compelling take on urban drag racing. In CSR Racing, you don't steer. It's a flat out drag-race so the game is won by precise starts, perfectly timed gear-shifts and a tricked out car. What could just be a drab series of taps is paired with slick graphics that show off the high performance cars and environments. CSR Racing is free to play, so gameplay mechanics do fish for cash from players. These include a gold premium currency, as well as a 'gas' resource that is expended every time you race (it refreshes over time, or can be filled with in-app purchases).

5. Need For Speed: Most Wanted (Android, iOS) ($6.99)



Need for Speed: Most Wanted is starting to show its age, but still delivers adrenaline-pumping racing action. Players take the wheel of any of 40 of the world's hottest rides for intense street races, all while avoiding hyper-aggressive police pursuit vehicles. Compete in numerous game modes, from the classic six-way races to time attacks and speed runs then climb up the ladder to become the most wanted.

6. Riptide GP 2 (Android, iOS) ($1.99)



Take to the waves in Vector Unit's Riptide GP 2, featuring a single player career mode and online four-way multiplayer races. Collect and customize any of nine powerful watercraft, tricking each one out for the race. Unlock and unleash 25 new stunts to wow the crowd, build up your boost, and leave the opposition sucking in your spray. A career mode offers more than 30 races and numerous game modes, with players earning XP in exchange for tricks and money for buying and upgrading their watercraft. Races can be traditional sprints for podium positions, hot lap, elimination or freestyle events.

7. Drift Mania: Street Outlaws (Android, iOS) ($0.99)



Slip and slide to victory in Drift Mania: Street Outlaws, the latest in Ratrod's drift racing series. Race your way through mountain passes, hillside towns, and desert canyons, tires screaming as you pull off insane turns on your way to the finish line. Tuners will go nuts over the extreme customization you can apply to your vehicles, tweaking your suspension, gears, and weight distribution to suit your driving style. The game doesn't just measure your speed.

8. Reckless Racing 2 (Android, iOS) ($1.99)



Polarbit's Reckless Racing 2 delivers some impressive top-down racing action. Graphics and gameplay are well rendered and the game offers numerous control schemes, such as tilt and virtual keys. Gameplay modes include race, hot lap and elimination, with a career and arcade mode. Online multiplayer lets you duke it out with up to three other players. Each car can be customized with numerous parts and upgrades, with Reckless Racing cleverly preserving game balance by limiting races to cars of certain performance index scores.

9. Red Bull Air Race (Android, iOS) (Free)



Take to the skies with Red Bull Air Race, the world's fastest motorsport, now on mobile devices. Take control of some of the world's most maneuverable aerobatic planes, advance up the ranks from novice to master pilot, and square off against some of the sport's most famous pilots. Explore real world locations, engage in death-defying aerobatic stunts, and conquer the skies.

Four stroke diesel engine

Just like the four-stroke-cycle petrol engine, the Compression-ignition (C.I.) engine completes one cycle of events in two crankshaft revolutions or four piston strokes. The four phases of these strokes are (i) induction of fresh air, (ii) compression and heating of this air, (iii) injection of fuel and its burning and expansion, and (iv) expulsion of the products of combustion.

1) Induction stroke With the inlet valve open and the exhaust valve closed, the piston moves away from the cylinder head.

The outward movement of the piston will establish a depression in the cylinder, its magnitude depending on the ratio of the cross-sectional areas of the cylinder and the inlet port and on the speed at which the piston is moving. The pressure difference established between the inside and outside of the cylinder will induce air at atmospheric pressure to enter and fill up the cylinder. Unlike the petrol engine, which requires a charge of air-and-petrol mixture to be drawn past a throttle valve, in the diesel-engine inlet system no restriction is necessary and only pure air is induced into the cylinder. A maximum depression of maybe 0.15 bar below atmospheric pressure will occur at about one-third of the distance along the piston's outward stroke, while the overall average pressure in the cylinder might be 0.1 bar or even less.

2) Compression stroke With both the inlet and the exhaust valves closed, the piston moves towards the cylinder head.

The air enclosed in the cylinder will be compressed into a much smaller space of anything from 1/12 to 1/24 of its original volume. A typical ratio of maximum to minimum air-charge volume in the cylinder would be 16:1, but this largely depends on engine size and designed speed range.

During the compression stroke, the air charge initially at atmospheric pressure and temperature is reduced in volume until the cylinder pressure is raised to between 30 and 50 bar. This compression of the air generates heat which will increase the charge temperature to at least 600 °C under normal running conditions.

3) Power stroke With both the inlet and the exhaust valves closed and the piston almost at the end of the compression stroke , diesel fuel oil is injected into the dense and heated air as a high-pressure spray of fine particles. Provided that they are properly atomized and distributed throughout the air charge, the heat of compression will then quickly vaporize and ignite the tiny droplets of liquid fuel. Within a very short time, the piston will have reached its innermost position and extensive burning then releases heat energy which is rapidly converted into pressure energy. Expansion then follows, pushing the piston away from the cylinder head, and the linear thrust acting on the piston end of the connecting-rod will then be changed to rotary movement of the crankshaft.

4) Ehaust stroke When the burning of the charge is near completion and the piston has reached the outermost position, the exhaust valve is opened. The piston then reverses its direction of motion and moves towards the cylinder head