|
Serrated Blade
Serration is a saw-like appearance or a row of sharp or tooth-like projections. A serrated cutting edge has many small points of contact with the material being cut. By having less contact area than a smooth blade or other edge, the applied pressure at each point of contact is greater, and the points of contact are at a sharper angle to the material being cut. This causes a cutting action that involves many small splits in the surface of the material being cut, which cumulatively serve to cut the material along the line of the blade. Serration in nature In nature, serration is commonly seen in the cutting edge on the teeth of some species, usually sharks. However, it also appears on non-cutting surfaces, for example, in botany where a toothed leaf margin or other plant part, such as the edge of a carnation petal, is described as being serrated. A serrated leaf edge may reduce the force of wind and other natural elements. Probably the largest serrations on Earth occur on the s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tiger Shark Serration
The tiger (''Panthera tigris'') is a large Felidae, cat and a member of the genus ''Panthera'' native to Asia. It has a powerful, muscular body with a large head and paws, a long tail and orange fur with black, mostly vertical stripes. It is traditionally classified into nine Holocene, recent subspecies, though some recognise only two subspecies, mainland Asian tigers and the island tigers of the Sunda Islands. Throughout the tiger's range, it inhabits mainly forests, from coniferous and temperate broadleaf and mixed forests in the Russian Far East and Northeast China to tropical and subtropical moist broadleaf forests on the Indian subcontinent and Southeast Asia. The tiger is an apex predator and preys mainly on ungulates, which it takes by ambush. It lives a mostly solitary life and occupies home ranges, defending these from individuals of the same sex. The range of a male tiger overlaps with that of multiple females with whom he mates. Females give birth to usually two or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Screw Thread
A screw thread is a helical structure used to convert between rotational and linear movement or force. A screw thread is a ridge wrapped around a cylinder or cone in the form of a helix, with the former being called a ''straight'' thread and the latter called a ''tapered'' thread. A screw thread is the essential feature of the screw as a simple machine and also as a threaded fastener. The mechanical advantage of a screw thread depends on its ''lead'', which is the linear distance the screw travels in one revolution. In most applications, the lead of a screw thread is chosen so that friction is sufficient to prevent linear motion being converted to rotary, that is so the screw does not slip even when linear force is applied, as long as no external rotational force is present. This characteristic is essential to the vast majority of its uses. The tightening of a fastener's screw thread is comparable to driving a wedge into a gap until it sticks fast through friction and slight ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sharpening Stone
Sharpening stones, or whetstones, are used to sharpening, sharpen the edges of steel tools such as knife, knives through grinding and Honing (metalworking), honing. Such stones come in a wide range of shapes, sizes, and material compositions. They may be flat, for working flat edges, or shaped for more complex edges, such as those associated with some wood carving or woodturning tools. They may be composed of natural quarried material or from man-made material. They come in various grades, which refer to the Mesh (scale), grit size of the abrasive particles in the stone. (Grit size is given as a number, which indicates the spatial density of the particles; a higher number denotes a higher density and therefore smaller particles, which give a finer finish to the surface of the sharpened object.) Stones intended for use on a workbench are called bench stones, while small, portable ones, whose size makes it hard to draw large blades uniformly over them, especially "in the field", ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bread Knife
Bread knives are used for cutting bread and are one of many kitchen knife, kitchen knives used by cooks. The serrated blades of bread knives are able to cut soft bread without crushing it. History One such knife was exhibited at the World's Columbian Exposition in 1893 in Chicago by the Friedrich Dick company (Esslingen, Germany). One design was patented in the United States by Joseph E. Burns of Syracuse, New York, in 1919, predating the invention of automatically sliced bread by about ten years. His knife had sections of grooves or serrations, inclined with respect to the axis of the blade, that form individual small cutting edges which were perpendicular to the blade and thus cut without the excessive normal pressure required of a scalloped blade and without the horizontal force required by positive-raked teeth that would dig into the bread like a wood saw. There were also sections of grooves with the opposite direction of inclination, separated by a section of smooth blade ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scissors
Scissors are hand-operated shearing tools. A pair of scissors consists of a pair of blades pivoted so that the sharpened edges slide against each other when the handles (bows) opposite to the pivot are closed. Scissors are used for cutting various thin materials, such as paper, paperboard, cardboard, metal leaf, metal foil, cloth, rope, and wire. A large variety of scissors and shears all exist for specialized purposes. Hair-cutting shears and kitchen shears are functionally equivalent to scissors, but the larger implements tend to be called Shears (other)#Cutting devices, shears. Hair-cutting shears have specific blade angles ideal for cutting hair. Using the incorrect type of scissors to cut hair will result in increased damage or split ends, or both, by breaking the hair. Kitchen shears, also known as kitchen scissors, are intended for cutting and trimming foods such as meats. Inexpensive, mass-produced modern scissors are often designed ergonomically with composite ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Knife
A knife (: knives; from Old Norse 'knife, dirk') is a tool or weapon with a cutting edge or blade, usually attached to a handle or hilt. One of the earliest tools used by humanity, knives appeared at least Stone Age, 2.5 million years ago, as evidenced by the Oldowan tools. Originally made of wood, bone, and stone (such as flint and obsidian), over the centuries, in step with improvements in both metallurgy and manufacturing, knife blades have been made from copper, bronze, iron, steel, ceramic, and titanium. Most modern knives have either fixed or folding blades; blade patterns and styles vary by maker and country of origin. Knives can serve various purposes. Hunters use a hunting knife, soldiers use the combat knife, scouts, campers, and hiking, hikers carry a pocketknife; there are kitchen knives for preparing foods (the chef's knife, the paring knife, bread knife, cleaver), table knife (butter knives and steak knives), weapons (daggers or switchblades), knives for throwing o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flint
Flint, occasionally flintstone, is a sedimentary cryptocrystalline form of the mineral quartz, categorized as the variety of chert that occurs in chalk or marly limestone. Historically, flint was widely used to make stone tools and start fires. Flint occurs chiefly as nodules and masses in sedimentary rocks, such as chalks and limestones.''The Flints from Portsdown Hill'' Inside the nodule, flint is usually dark grey or black, green, white, or brown in colour, and has a glassy or waxy appearance. A thin, oxidised layer on the outside of the nodules is usually different in colour, typically white and rough in texture. The nodules can often be found along s and [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mesolithic
The Mesolithic (Ancient Greek language, Greek: μέσος, ''mesos'' 'middle' + λίθος, ''lithos'' 'stone') or Middle Stone Age is the Old World archaeological period between the Upper Paleolithic and the Neolithic. The term Epipaleolithic is often used synonymously, especially for outside northern Europe, and for the corresponding period in Epipaleolithic Near East, the Levant and Epipaleolithic Caucasus, Caucasus. The Mesolithic has different time spans in different parts of Eurasia. It refers to the final period of hunter-gatherer cultures in Europe and the Middle East, between the end of the Last Glacial Maximum and the Neolithic Revolution. In Europe it spans roughly 15,000 to 5,000 Before Present, BP; in the Middle East (the Epipalaeolithic Near East) roughly 20,000 to 10,000 Before Present, BP. The term is less used of areas farther east, and not at all beyond Eurasia and North Africa. The type of culture associated with the Mesolithic varies between areas, b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clamp (tool)
A clamp is a fastener, fastening device used to hold or secure objects tightly together to prevent movement or separation through the application of inward pressure. In the United Kingdom the term cramp is often used instead when the tool is for temporary use for positioning components during construction and woodworking; thus a C clamp, G cramp or a sash clamp but a wheel clamp or a surgical clamp. There are many types of clamps available for many different purposes. Some are temporary, as used to position components while fixing them together, others are intended to be permanent. In the field of animal husbandry, using a clamp to attach an animal to a stationary object is known as "rounded clamping." A physical clamp of this type is also used to refer to an obscure investment banking term, "fund clamps." Anything that performs the action of clamping may be called a clamp, so this gives rise to a wide variety of terms across many fields. Types Temporary These clamps (or cram ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brogue Shoe
The brogue (from Scottish Gaelic and Irish Gaelic , both meaning "shoe") is a style of low-heeled shoe or boot traditionally characterised by multiple-piece, sturdy leather uppers with decorative perforations (or "broguing") and serration along the pieces' visible edges. Brogues were traditionally considered to be outdoor or country footwear, as the perforations were originally intended to allow the upper to dry more quickly in wet climates. As such, they were otherwise considered not appropriate for casual or business occasions, but brogues are now considered appropriate in most contexts. Brogues are most commonly found in one of four toe cap styles — full or "wingtip", semi-, quarter and longwing — and four closure styles, namely Oxford, Derby, ghillie, and monk. Today, as well as their typical form of sturdy leather shoes or boots, brogues may take the form of business dress shoes, sneakers, high-heeled women's shoes, or any other shoe form that utilises or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stealth Aircraft
Stealth aircraft are designed to avoid detection using a variety of technologies that reduce reflection/emission of radar, infrared, visible light, radio frequency (RF) spectrum, and audio, collectively known as stealth technology. The F-117 Nighthawk was the first operational aircraft explicitly designed around stealth technology. Other examples of stealth aircraft include the Northrop Grumman B-2 Spirit, B-2 Spirit, the B-21 Raider, the Lockheed Martin F-22 Raptor, F-22 Raptor, the F-35 Lightning II, the Chengdu J-20, and the Sukhoi Su-57. While no aircraft is completely invisible to radar, stealth aircraft make it more difficult for conventional radar to detect or track the aircraft effectively, increasing the odds of an aircraft avoiding detection by enemy radar and/or avoiding being successfully targeted by Semi-active radar guidance, radar guided weapons. Stealth is a combination of passive low observable (LO) features and active emitters such as low-probability-of-interc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
