Feather

Feathers are epidermal growths that form the distinctive outer covering, or plumage, on birds and some non-avian theropod dinosaurs. They are considered the most complex integumentary structures found in vertebrates, and indeed a premier example of a complex evolutionary novelty. They are among the characteristics that distinguish the extant Aves from other living groups. Feathers have also been noticed in those Theropoda which have been termed feathered dinosaurs.

Although feathers cover most parts of the body of birds, they arise only from certain well-defined tracts on the skin. They aid in flight, thermal insulation, and waterproofing. In addition, coloration helps in communication and protection.Plumology (or plumage science) is the name for the science that is associated with the study of feathers.

Structures and characteristics

Feathers are among the most complex integumentary appendages found in vertebrates and are formed in tiny follicles in the epidermis, or outer skin layer, that produce keratin proteins. The β-keratins in feathers, beaks and claws — and the claws, scales and shells of reptiles — are composed of protein strands hydrogen-bonded into β-pleated sheets, which are then further twisted and crosslinked by disulfide bridges into structures even tougher than the α-keratins of mammalian hair, horns and hoof. The exact signals that induce the growth of feathers on the skin are not known, but it has been found that the transcription factor cDermo-1 induces the growth of feathers on skin and scales on the leg.

Blade

A blade is the portion of a tool, weapon, or machine with an edge that is designed to cut and/or puncture, stab, slash, chop, slice, thrust, or scrape surfaces or materials. A blade may be made from a flaking stone, such as flint, metal (usually steel), ceramic, or other material. Blades are one of humanity's oldest tools, and continue to be used for combat, food preparation, and other purposes.

Uses

During food preparation, knives are mainly used for slicing, chopping, and piercing.

In combat, a blade may be used to slash or puncture, and may also be thrown or otherwise propelled. The function is to sever a nerve, muscle or tendon fibers, or blood vessel to disable or kill the adversary. Severing a major blood vessel typically leads to death due to exsanguination. Shrapnel wounds via the fragments' blade-like nature.

Blades may be used to scrape, moving the blade sideways across a surface, as in an ink eraser, rather than along or through a surface.

Physics

A simple blade intended for cutting has two faces that meet at an edge. Ideally this edge would have no roundness but in practice all edges can be seen to be rounded to some degree under magnification either optically or with an electron microscope. Force is applied to the blade, either from the handle or pressing on the back of the blade. The handle or back of the blade has a large area compared to the fine edge. This concentration of applied force onto the small edge area increases the pressure exerted by the edge. It is this high pressure that allows a blade to cut through a material by breaking the bonds between the molecules/crystals/fibres/etc. in the material. This necessitates the blade being strong enough to resist breaking before the other material gives way.

Razor

A razor is a bladed tool primarily used in the removal of unwanted body hair through the act of shaving. Kinds of razors include straight razors, disposable razor, and electric razors.

While the razor has been in existence since before the Bronze Age (the oldest razor like-object has been dated to 18,000 B.C.), its modern counterpart was invented in the 18th century, and the 1930s saw the invention of electric razors. In the 21st century, the safety razor – electric or not – is most commonly used by both men and women, but other kinds still exist.

History

Razors have been identified from many Bronze Age cultures. These were made of bronze or obsidian and were generally oval in shape, with a small tang protruding from one of the short ends.

Various forms of razors were used throughout history, which are different in appearance but similar in use to modern straight razors. In prehistoric times clam shells, shark teeth, and flint were sharpened and used to shave with. Drawings of such blades were found in prehistoric caves. Some tribes still use blades made of flint to this day. Excavations in Egypt have unearthed solid gold and copper razors in tombs dating back to the 4th millennium BC. The Roman historian Livy reported that the razor was introduced in ancient Rome in the 6th century BC. by legendary king Lucius Tarquinius Priscus. Priscus was ahead of his time because razors did not come to general use until a century later.

Quality Meat Scotland

Quality Meat Scotland (QMS) is an executive non-departmental public body of the Scottish Government. It promotes the red meat sector and markets the Protected Geographical Indication Scotch Beef and Scotch Lamb brands.

It was set up in 1990 to provide assurance to industry and consumers that animals produced for the food chain met certain standards.

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Razor Blade

The Aston Martin Razor Blade team car was built in 1923 to break the one-hour light car record of 101.39 mph (163.17 km/h) held by AC Cars. Although it failed to break the record, it did have success in race and record attempts in the 1920s.

The August 1923 issue of The Light Car & Cyclecar magazine stated:

The latest Aston Martin racer… represents the greatest advance in high efficiency small car design.

History

Standard Aston Martin parts were used on a specially built narrow chassis with quarter elliptic springs at the rear. The engine had previously been developed for the 1922 French Grand Prix by Aston Martin. It was based on half a 1921 three-litre eight-cylinder Ballot engine giving a four-cylinder configuration, with twin overhead camshafts, 16 valves, and 1.5 litres capacity. It produced 55 bhp (41 kW) at 4,200 rpm.

The body was built by the de Havilland Aircraft Company and is 18 ¹⁄₂ inches (47 cm) at its widest point. It is said to be the narrowest racing car ever built. The original design was for the body to be fully enclosed, but Lionel Martin was unable to find a driver small enough to fit in it. Originally code named the Oyster, the car was soon called the Razor Blade.