Sunday, 30 September 2012

Second law of Thermodynamics in life

Energy in 3 consecutive forms: potential, kine...

Energy in 3 consecutive forms: potential, kinetic, internal (Photo credit: Wikipedia)

A Falling Rock

A rock has potential energy (PE) localized in it when you lift it up above the ground. The rock is the system; everything else it encounters is the surroundings. Drop the rock and its PE changes to kinetic energy (energy of movement, KE), pushing air aside as it falls (therefore spreading out the rock’s KE a bit) before it hits the ground, dispersing a tiny bit of sound energy (compressed air) and causing a little heating (molecular motion energy) of the ground it hits and in the rock itself. The rock is unchanged (after a minute when it disperses to the air the small amount of heat it got from hitting the ground). But the potential energy that your muscles localized in by lifting it up is now totally spread out and dispersed all over in a little air movement and a little heating of the air and ground.

A Hot Frying Pan

A hot frying pan? The iron atoms in a hot frying pan (system) in a room (surroundings) are vibrating very rapidly, like fast "dancing in place". Therefore, considering both the pan and the room, the motion energy in the hot pan is localized. That motion energy will disperse—if it is not hindered, according to the second law. Whenever the less rapidly moving molecules in the cooler air of the room hit the hot pan, the fast-vibrating iron atoms transfer some of their energy to the air molecules. The pan’s localized energy thus becomes dispersed, spread out more widely to molecules in the room air.

Friday, 21 September 2012

Ship camouflage

WWI troopship, SS Empress of Russia, painted i...

WWI troopship, SS Empress of Russia, painted in "dazzle" camouflage markings (Photo credit: Wikipedia)

     

 

 

 

Camouflage

Brtish dpm2.jpg

Ship camouflage is a form of military deception in which a ship is painted in one or more colours in order to obscure or confuse an enemy's visual observation.

Thursday, 20 September 2012

Tonnage

Tonnage mark

Tonnage mark (Photo credit: Wikipedia)

     

              Tonnage is a measure of the size or cargo carrying capacity of a ship. The term derives from the taxation paid on tuns or casks of wine, and was later used in reference to the weight of a ship's cargo; however, in modern maritime usage, "tonnage" specifically refers to a calculation of the volume or cargo volume of a ship. It is incorrect to use the term "tonnage" to refer to the loaded or empty weight of the vessel itself.

Weight measurements

              Displacement is the actual total weight of the vessel (mostly without pay load). It is often expressed in long tons or in metric tons, and is calculated simply by multiplying the volume of the hull below the waterline (i.e. the volume of water it is displacing) by the specific gravity of the water. (Note that the specific gravity will depend on whether the vessel is in fresh or salt water, or is in the tropics, where water is warmer and hence less dense.) For example, in sea water, first determine the volume of the submerged portion of the hull as follows: Multiply its length by its breadth and the draft, all in feet. Then multiply the product thereby obtained by the block coefficient of the hull to get the hull volume in cubic feet. Then multiply this figure by 64 (the weight of one cubic foot of seawater) to get the weight of the ship in pounds; or divide by 35 to calculate the weight in long tons. Using the SI or metric system : displacement (in tonnes) is volume (in m³) multiplied by the specific gravity of sea water (1.025 nominally).

The word "displacement" arises from the basic physical law, discovered by Archimedes, that the weight of a floating object equates exactly to that of the water which would otherwise occupy the "hole in the water" displaced by the ship.

Lightship or Lightweight measures the actual weight of the ship with no fuel, passengers, cargo, water, etc. on board.

Deadweight tonnage (often abbreviated as DWT for deadweight tonnes) is the displacement at any loaded condition minus the lightship weight. It includes the crew, passengers, cargo, fuel, water, and stores. Like Displacement, it is often expressed in long tons or in metric tons.

Metric Tonnes per Centimetre Immersion (usually abbreviated to TPC or TPCMI ) is the number of Metric Tonnes (1,000KG) that need to be loaded on the ship for the salt water draft to increase by one centimetre.

Imperial Tons per Inch immersion (usually abbreviated to TPI) is the number of Imperial Long Tons (2,240 lbs) that need to be loaded on a vessel for the draft to increase by one inch. Old imperial TPI measurements are still occasionally used within the USA and the Panama canal. As no ship has been measured by a Classification Society since the 1950s using Imperial measures, modern TPI figures are therefore a conversion from the original Metric measurements and should not be relied upon to be accurate.

The TPCMI figure is used to calculate the draft of the vessel with a given DWT of cargo loaded. On a typical Panamax Bulk carrier with a TPCMI of 80, it would mean that the ship will sink (Draft increase) by one centimetre for every 80 tonnes of cargo loaded.

Draft The distance, usually measured in meters, between the lowest point of the keel and the waterline which varies dependant on the load (DWT) the vessel has on board

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Tuesday, 18 September 2012

Stealth aircraft

English: F-117A Stealth fighter aircraft from ...

English: F-117A Stealth fighter aircraft from the 37th Tactical Fighter Wing, Tonopah Test Range, Nev., line the runway after arriving for an overnight stay while deploying to Saudi Arabia during Operation Desert Shield. Location: LANGLEY AIR FORCE BASE, VIRGINIA (VA) UNITED STATES OF AMERICA (USA) (Photo credit: Wikipedia)

Stealth aircraft are aircraft that use stealth technology to avoid detection by employing a combination of features to interfere with radar as well as reduce visibility in the infrared, visual, audio, and radio frequency (RF) spectrum. Development of stealth technology likely began in Germany during World War II. Well-known modern examples of stealth aircraft include the United States' F-117 Nighthawk (1981–2008), the B-2 Spirit, the F-22 Raptor, and the F-35 Lightning II.

Monday, 17 September 2012

The hot bulb engine

 

            The hot bulb engine, or hotbulb or heavy oil engine is a type of internal combustion engine. It is an engine in which fuel is ignited by being brought into contact with a red-hot metal surface inside a bulb.

Most hot bulb engines were produced as one-cylinder low-speed two-stroke crankcase scavenging units.

The concept of this engine was established by Herbert Akroyd Stuart at the end of the 19th century. The first prototypes were built in 1886 and production started in 1891 by Richard Hornsby & Sons of Grantham, Lincolnshire, England under the title Hornsby Akroyd Patent Oil Engine under licence.

Sunday, 16 September 2012

The Nine Unknown

 

 

The Nine Unknown is allegedly a secret society founded by the Mauryan Emperor Asoka around 270 BC to preserve and develop knowledge that would be dangerous to humanity if it fell into the wrong hands.

The nine books entrusted to the Nine Unknown contain information on (1) Propaganda and Psychological warfare, (2) Physiology, including secrets concerning the "touch of death", (3) Microbiology, (4) Alchemy, (5) Communication, including communication with extraterrestrials, (6) Gravity, and anti-gravity devices (Vimanas, mythological flying machines of ancient India), (7) Cosmology, including hyperspace and time-travel, (8) Light, and a technology capable of modifying the speed of light and (9) Sociology, including rules predicting the rise and fall of empires