A tool is an object used to extend the ability of an individual to modify features of the surrounding environment. Although many animals use simple tools, only human beings, whose use of stone tools dates back hundreds of millennia, use tools to make other tools; the set of tools needed to perform different tasks that are part of the same activity is called gear or equipment. While one may apply the term tool loosely to many things that are means to an end speaking an object is a tool only if, besides being constructed to be held, it is made of a material that allows its user to apply to it various degrees of force. If repeated use wears part of the tool down, it may be possible to restore it, thus tool falls under the taxonomic category implement, is on the same taxonomic rank as instrument, device, or ware. Anthropologists believe; because tools are used extensively by both humans and wild chimpanzees, it is assumed that the first routine use of tools took place prior to the divergence between the two species.
These early tools, were made of perishable materials such as sticks, or consisted of unmodified stones that cannot be distinguished from other stones as tools. Stone artifacts only date back to about 2.5 million years ago. However, a 2010 study suggests the hominin species Australopithecus afarensis ate meat by carving animal carcasses with stone implements; this finding pushes back the earliest known use of stone tools among hominins to about 3.4 million years ago. Finds of actual tools date back at least 2.6 million years in Ethiopia. One of the earliest distinguishable stone tool forms is the hand axe. Up until weapons found in digs were the only tools of “early man” that were studied and given importance. Now, more tools are recognized as culturally and relevant; as well as hunting, other activities required tools such as preparing food, “…nutting, grain harvesting and woodworking…” Included in this group are “flake stone tools". Tools are the most important items that the ancient humans used to climb to the top of the food chain.
“Man the hunter” as the catalyst for Hominin change has been questioned. Based on marks on the bones at archaeological sites, it is now more evident that pre-humans were scavenging off of other predators' carcasses rather than killing their own food. Mechanical devices experienced a major expansion in their use in Ancient Greece and Ancient Rome with the systematic employment of new energy sources waterwheels, their use expanded through the Dark Ages with the addition of windmills. Machine tools occasioned a surge in producing new tools in the industrial revolution. Advocates of nanotechnology expect a similar surge. One can classify tools according to their basic functions: Cutting and edge tools, such as the knife, scythe or sickle, are wedge-shaped implements that produce a shearing force along a narrow face. Ideally, the edge of the tool needs to be harder than the material being cut or else the blade will become dulled with repeated use, but resilient tools will require periodic sharpening, the process of removing deformation wear from the edge.
Other examples of cutting tools include gouges and drill bits. Moving tools move tiny items. Many are levers. Examples of force-concentrating tools include the hammer which moves a nail or the maul which moves a stake; these operate by applying physical compression to a surface. In the case of the screwdriver, the force called torque. By contrast, an anvil concentrates force on an object being hammered by preventing it from moving away when struck. Writing implements deliver a fluid to a surface via compression to activate the ink cartridge. Grabbing and twisting nuts and bolts with pliers, a glove, a wrench, etc. move items by some kind of force. Tools that enact chemical changes, including temperature and ignition, such as lighters and blowtorches. Guiding and perception tools include the ruler, set square, straightedge, microscope, clock, printer Shaping tools, such as molds, trowels. Fastening tools, such as welders, rivet nail guns, or glue guns. Information and data manipulation tools, such as computers, IDE, spreadsheetsSome tools may be combinations of other tools.
An alarm-clock is for example a combination of a perception tool. This enables the alarm-clock to be a tool. There is some debate on whether to consider protective gear items as tools, because they do not directly help perform work, just protect the worker like ordinary clothing, they do meet the general definition of tools and in many cases are necessary for the completion of the work. Personal protective equipment includes such items as gloves, safety glasses, ear defenders and biohazard suits. A simple machine is a mechanical device that changes the magnitude of a force. In general, they are the simplest mechanisms; the six classical simple machines which were defined by Renaissance scientists are: Lever Wheel and axle Pulley Inclined plane Wedge Screw Often, by design or coincidence, a tool may share key functional attributes with one or more other tools. In this case, s
A flywheel is a mechanical device designed to efficiently store rotational energy. Flywheels resist changes in rotational speed by their moment of inertia; the amount of energy stored in a flywheel is proportional to the square of its rotational speed. The way to change a flywheel's stored energy is by increasing or decreasing its rotational speed by applying a torque aligned with its axis of symmetry, Common uses of a flywheel include: Smoothing the power output of an energy source. For example, flywheels are used in reciprocating engines because the active torque from the individual pistons is intermittent. Energy storage systems Delivering energy at rates beyond the ability of an energy source; this is achieved by collecting energy in a flywheel over time and releasing it at rates that exceed the abilities of the energy source. Controlling the orientation of a mechanical system and reaction wheelFlywheels are made of steel and rotate on conventional bearings. High energy density flywheels can be made of carbon fiber composites and employ magnetic bearings, enabling them to revolve at speeds up to 60,000 RPM.
Carbon-composite flywheel batteries have been manufactured and are proving to be viable in real-world tests on mainstream cars. Additionally, their disposal is more eco-friendly than traditional lithium ion batteries. Flywheels are used to provide continuous power output in systems where the energy source is not continuous. For example, a flywheel is used to smooth fast angular velocity fluctuations of the crankshaft in a reciprocating engine. In this case, a crankshaft flywheel stores energy when torque is exerted on it by a firing piston, returns it to the piston to compress a fresh charge of air and fuel. Another example is the friction motor. In unstressed and inexpensive cases, to save on cost, the bulk of the mass of the flywheel is toward the rim of the wheel. Pushing the mass away from the axis of rotation heightens rotational inertia for a given total mass. A flywheel may be used to supply intermittent pulses of energy at power levels that exceed the abilities of its energy source; this is achieved by accumulating energy in the flywheel over a period of time, at a rate, compatible with the energy source, releasing energy at a much higher rate over a short time when it is needed.
For example, flywheels are used in riveting machines. Flywheels oppose unwanted motions, see gyroscope. Flywheels in this context have a wide range of applications from gyroscopes for instrumentation to ship stability and satellite stabilization, to keep a toy spin spinning, to stabilize magnetically levitated objects The principle of the flywheel is found in the Neolithic spindle and the potter's wheel, as well as circular sharpening stones in antiquity; the mechanical flywheel, used to smooth out the delivery of power from a driving device to a driven machine and to allow lifting water from far greater depths, was first employed by Ibn Bassal, of Al-Andalus. The use of the flywheel as a general mechanical device to equalize the speed of rotation is, according to the American medievalist Lynn White, recorded in the De diversibus artibus of the German artisan Theophilus Presbyter who records applying the device in several of his machines. In the Industrial Revolution, James Watt contributed to the development of the flywheel in the steam engine, his contemporary James Pickard used a flywheel combined with a crank to transform reciprocating motion into rotary motion.
A flywheel is rotor, rotating around its symmetry axis. Energy is stored as kinetic energy, more rotational energy, of the rotor: E k = 1 2 I ω 2 where: E k is the stored kinetic energy, ω is the angular velocity, I is the moment of inertia of the flywheel about its axis of symmetry; the moment of inertia is a measure of resistance to torque applied on a spinning object. The moment of inertia for a solid cylinder is I = 1 2 m r 2, for a thin-walled empty cylinder is I = m r 2, for a thick-walled empty cylinder is I = 1 2 m,where m denotes mass, r denotes a radius; when calculating with SI units, the units would be for kilograms. Increasing amounts of rotation energy can be stored in the flywheel until the rotor
Antlers are extensions of an animal's skull found in members of the deer family. They are a single structure, they are found only on males, with the exception of the caribou. Antlers are shed and regrown each year and function as objects of sexual attraction and as weapons in fights between males for control of harems. In contrast, found on pronghorns and bovids such as sheep, goats and cattle, are two-part structures. An interior of bone is covered by an exterior sheath grown by specialized hair follicles, the same material as human fingernails and toenails. Horns continue to grow throughout the animal's life; the exception to this rule is the Pronghorn which regrows its horn sheath each year. They grow in symmetrical pairs. Antler comes from the Old French antoillier from some form of an unattested Latin word *anteocularis, "before the eye". Antlers are unique to cervids; the ancestors of deer had tusks. In most species, antlers appear to replace tusks. However, two modern species have tusks and no antlers and the muntjac has small antlers and tusks.
Antlers are found only on males. Only reindeer have antlers on the females, these are smaller than those of the males. Fertile does from other species of deer have the capacity to produce antlers on occasion due to increased testosterone levels; the "horns" of a pronghorn meet some of the criteria of antlers, but are not considered true antlers because they contain keratin. Each antler grows from an attachment point on the skull called a pedicle. While an antler is growing, it is covered with vascular skin called velvet, which supplies oxygen and nutrients to the growing bone. Antlers are considered one of the most exaggerated cases of male secondary sexual traits in the animal kingdom, grow faster than any other mammal bone. Growth occurs at the tip, is cartilage, replaced by bone tissue. Once the antler has achieved its full size, the velvet is lost and the antler's bone dies; this dead bone structure is the mature antler. In most cases, the bone at the base is destroyed by osteoclasts and the antlers fall off at some point.
As a result of their fast growth rate, antlers are considered a handicap since there is an immense nutritional demand on deer to re-grow antlers annually, thus can be honest signals of metabolic efficiency and food gathering capability. In most arctic and temperate-zone species, antler growth and shedding is annual, is controlled by the length of daylight. Although the antlers are regrown each year, their size varies with the age of the animal in many species, increasing annually over several years before reaching maximum size. In tropical species, antlers may be shed at any time of year, in some species such as the sambar, antlers are shed at different times in the year depending on multiple factors; some equatorial deer never shed their antlers. Antlers function as weapons in combats between males, which sometimes cause serious wounds, as dominance and sexual displays; the principal means of evolution of antlers is sexual selection, which operates via two mechanisms: male-to-male competition and female mate choice.
Male-male competition can take place in two forms. First, they can compete behaviorally where males use their antlers as weapons to compete for access to mates. Males with the largest antlers are more to obtain mates and achieve the highest fertilization success due to their competitiveness and high phenotypic quality. Whether this is a result of male-male fighting or display, or of female choosiness differs depending on the species as the shape and function of antlers vary between species. There is evidence to support that antler size influences mate selection in the red deer, has a heritable component. Despite this, a 30-year study showed no shift in the median size of antlers in a population of red deer; the lack of response could be explained by environmental covariance, meaning that lifetime breeding success is determined by an unmeasured trait, phenotypically correlated with antler size but for which there is no genetic correlation of antler growth. Alternatively, the lack of response could be explained by the relationship between heterozygosity and antler size, which states that males heterozygous at multiple loci, including MHC loci, have larger antlers.
The evolutionary response of traits that depend on heterozygosity is slower than traits that are dependent on additive genetic components and thus the evolutionary change is slower than expected. A third possibility is that the costs of having larger antlers exert enough selective pressure to offset the benefit of attracting mates. If antlers functioned only in male–male competition for mates, the best evolutionary strategy would be to shed them after the rutting season, both to free the male from a heavy encumbrance and to give him more time to regrow a larger new pair, yet antlers are retained through the winter and into the spring, suggesting that they have another use. Wolves in Yellowstone National Park are 3.6 times more to
Populus is a genus of 25–35 species of deciduous flowering plants in the family Salicaceae, native to most of the Northern Hemisphere. English names variously applied to different species include poplar and cottonwood. In the September 2006 issue of Science Magazine, the Joint Genome Institute announced that the western balsam poplar was the first tree whose full DNA code had been determined by DNA sequencing; the genus has a large genetic diversity, can grow from 15–50 m tall, with trunks up to 2.5 m in diameter. The bark on young trees is smooth, white to greenish or dark grey, has conspicuous lenticels; the shoots are stout, with the terminal bud present. The leaves are spirally arranged, vary in shape from triangular to circular or lobed, with a long petiole. Leaf size is variable on a single tree with small leaves on side shoots, large leaves on strong-growing lead shoots; the leaves turn bright gold to yellow before they fall during autumn. The flowers are dioecious and appear in early spring before the leaves.
They are borne in long, sessile or pedunculate catkins produced from buds formed in the axils of the leaves of the previous year. The flowers are each seated in a cup-shaped disk, borne on the base of a scale, itself attached to the rachis of the catkin; the scales are obovate and fringed, hairy or smooth, caducous. The male flowers are without calyx or corolla, comprise a group of four to 60 stamens inserted on a disk; the female flower has no calyx or corolla, comprises a single-celled ovary seated in a cup-shaped disk. The style is short, with two to four stigmata, variously lobed, numerous ovules. Pollination is by wind, with the female catkins lengthening between pollination and maturity; the fruit is a two- to four-valved dehiscent capsule, green to reddish-brown, mature in midsummer, containing numerous minute light brown seeds surrounded by tufts of long, white hairs which aid wind dispersal. Poplars of the cottonwood section are wetlands or riparian trees; the aspens are among the most important boreal broadleaf trees.
Poplars and aspens are important food plants for the larvae of a large number of Lepidoptera species. Pleurotus populinus, the aspen oyster mushroom, is found on dead wood of Populus trees in North America. Several species of Populus in the United Kingdom and other parts of Europe have experienced heavy dieback; the genus Populus has traditionally been divided into six sections on the basis of leaf and flower characters. Recent genetic studies have supported this, confirming some suspected reticulate evolution due to past hybridisation and introgression events between the groups; some species had differing relationships indicated by their nuclear DNA and chloroplast DNA sequences, a clear indication of hybrid origin. Hybridisation continues to be common in the genus, with several hybrids between species in different sections known. Populus section Populus – aspens and white poplar Populus adenopoda – Chinese aspen Populus alba – white poplar Populus × canescens – grey poplar Populus spp. X – Pacific albus Populus davidiana – Korean aspen Populus grandidentata – bigtooth aspen Populus sieboldii – Japanese aspen Populus tremula – aspen, common aspen, Eurasian aspen, European aspen, quaking aspen Populus tremuloides – quaking aspen or trembling aspen Populus section Aigeiros – black poplars, some of the cottonwoods Populus deltoides – eastern cottonwood Populus fremontii – Fremont cottonwood Populus nigra – black poplar, placed here by nuclear DNA.
Populus Populus × canadensis – hybrid black poplar Populus × inopina – hybrid black poplar Populus section Tacamahaca – balsam poplars Populus angustifolia – willow-leaved poplar or narrowleaf cottonwood Populus balsamifera – Balsam poplar Populus cathayana – Populus koreana J. Rehnder – Korean poplar Populus laurifolia – laurel-leaf poplar Populus maximowiczii A. Henry – Maximowicz' poplar, Japanese poplar Populus simonii – Simon's poplar Populus suaveolens Fischer – Mongolian poplar Populus szechuanica – Sichuan poplar, placed here by nuclear DNA. Aigeiros Populus trichocarpa – western balsam poplar or black cottonwood Populus tristis, placed here by nuclear DNA.
The genus Aesculus, with varieties called buckeye and horse chestnut, comprises 13–19 species of flowering plants in the soapberry and lychee family Sapindaceae. They are trees and shrubs native to the temperate Northern Hemisphere, with six species native to North America and seven to 13 species native to Eurasia. Several hybrids occur. Aesculus exhibits a classical arcto-Tertiary distribution. Linnaeus named the genus Aesculus after the Roman name for an edible acorn. Common names for these trees include "buckeye" and "horse chestnut", though they are not in the same order as chestnut trees; some are called white chestnut or red chestnut. In Britain, they are sometimes called conker trees because of their link with the game of conkers, played with the seeds called conkers. Aesculus species have stout shoots with resinous sticky, buds. Species are evergreen. Flowers are showy, insect- or bird-pollinated, with four or five petals fused into a lobed corolla tube, arranged in a panicle inflorescence.
Flowering starts after 80–110 growing degree days. The fruit matures to a capsule known as a catjacket, 2–5 cm diameter globose, containing one to three seeds per capsule. Capsules containing more than one seed result in flatness on one side of the seeds; the point of attachment of the seed in the capsule shows as a large circular whitish scar. The capsule epidermis has "spines" in some species, while other capsules are smooth. At maturity, the capsule splits into three sections to release the seeds. Aesculus seeds were traditionally eaten, after leaching, by the Jōmon people of Japan over about four millennia, until 300 AD. All parts of the buckeye or horse chestnut tree are moderately toxic, including the nut-like seeds; the toxin affects the gastrointestinal system. The USDA notes that the toxicity is due to saponin aescin and glucoside aesculin, with alkaloids contributing. Native Americans used to crush the seeds and the resulting mash was thrown into still or sluggish waterbodies to stun or kill fish.
They boiled and drained the fish at least three times to dilute the toxin's effects. New shoots from the seeds have been known to kill grazing cattle; the genus has traditionally been treated in the ditypic family Hippocastanaceae along with Billia, but recent phylogenetic analysis of morphological and molecular data has caused this family, along with the Aceraceae, to be included in the soapberry family. The species of Aesculus include: The most familiar member of the genus worldwide is the common horse chestnut, Aesculus hippocastanum; the yellow buckeye, Aesculus flava, is a valuable ornamental tree with yellow flowers, but is less planted. Among the smaller species is the bottlebrush buckeye, Aesculus parviflora, a flowering shrub. Several other members of the genus are used as ornamentals, several horticultural hybrids have been developed, most notably the red horse chestnut Aesculus × carnea, a hybrid between A. hippocastanum and A. pavia. Interpretations of the tree leaves can be seen in architectural details in the Reims Cathedral.
Leaf of Aesculus was the official symbol of the Kiev City during the Soviet Russia control of Ukraine, reflecting the consistent policy of cultivating the tree in the city since the late 20th century. In the 1840 U. S. Presidential Campaign, candidate William Henry Harrison called himself the "log cabin and hard cider candidate", portraying himself sitting in a log cabin made of buckeye logs and drinking hard cider, causing Ohio to become known as "the Buckeye State". Media related to Aesculus at Wikimedia Commons Data related to Aesculus at Wikispecies Germplasm Resources Information Network: Aesculus Forest, F. Drouin, J. N. Charest, R. Brouillet, L. & Bruneau A.. A morphological phylogenetic analysis of Aesculus L. and Billia Peyr.. Can. J. Bot. 79: 154–169. Abstract. Aesculus glabra King's American Dispensatory Winter ID pictures
An ember is a glowing, hot coal made of heated wood, coal, or other carbon-based material that remain after, or sometimes precede, a fire. Embers can glow hot, sometimes as hot as the fire which created them, they radiate a substantial amount of heat long after the fire has been extinguished, if not taken care of properly can rekindle a fire, thought to be extinguished and can pose a fire hazard. In order to avoid the danger of accidentally spreading a fire, many campers pour water on the embers or cover them in dirt. Alternatively, embers can be used to relight a fire after it has gone out without the need to rebuild the fire - In a conventional fireplace, a fire can be relit up to 12 hours after it goes out, provided that there is enough space for air to circulate between the embers and the introduced fuel, they are used for cooking, such as in charcoal barbecues. This is because embers radiate a more consistent form of heat, as opposed to an open fire, changing along with the heat it radiates.
An ember is formed when a fire has only burnt a piece of fuel, there is still usable chemical energy in that piece of fuel. This happens because the usable chemical energy is so deep into the center that air does not reach it, therefore not causing combustion, it continues to stay hot and does not lose its thermal energy because combustion is still happening at a low level. The small yellow and red lights seen among the embers are combustion. There just is not enough combustion happening at one time to create a flame. Once the embers are completely'burned through', they are not carbon as is believed, but rather various other oxidized minerals like calcium and phosphorus. At that point they are called ashes. See: Wood ash for more on the residue, left. Embers play a large role in forest fires; because embers are burnt leaves and thus small and lightweight, they can become airborne. During a large fire, with the right conditions, embers can be blown far ahead of the fire front, starting spot fires several kilometres/miles away.
A number of practical measures can be undertaken by homeowners to reduce the consequences of such an "ember attack" that bombards wooden structures and starts property fires. Spark, an airborne ember