Malta known as the Republic of Malta, is a Southern European island country consisting of an archipelago in the Mediterranean Sea. It lies 80 km south of Italy, 284 km east of Tunisia, 333 km north of Libya. With a population of about 475,000 over an area of 316 km2, Malta is the world's tenth smallest and fifth most densely populated country, its capital is Valletta, the smallest national capital in the European Union by area at 0.8 km.2 The official languages are Maltese and English, with Maltese recognised as the national language and the only Semitic language in the European Union. Malta has been inhabited since 5900 BC, its location in the centre of the Mediterranean has given it great strategic importance as a naval base, with a succession of powers having contested and ruled the islands, including the Phoenicians and Carthaginians, Greeks, Normans, Knights of St. John and British. Most of these foreign influences have left some sort of mark on the country's ancient culture. Malta became a British colony in 1815, serving as a way station for ships and the headquarters for the British Mediterranean Fleet.
It played an important role in the Allied war effort during the Second World War, was subsequently awarded the George Cross for its bravery in the face of an Axis siege, the George Cross appears on Malta's national flag. The British Parliament passed the Malta Independence Act in 1964, giving Malta independence from the United Kingdom as the State of Malta, with Queen Elizabeth II as its head of state and queen; the country became a republic in 1974. It has been a member state of the Commonwealth of Nations and the United Nations since independence, joined the European Union in 2004. Malta has a long Christian legacy and its Archdiocese is claimed to be an apostolic see because Paul the Apostle was shipwrecked on "Melita", according to Acts of the Apostles, now taken to be Malta. While Catholicism is the official religion in Malta, Article 40 of the Constitution states that "all persons in Malta shall have full freedom of conscience and enjoy the free exercise of their respective mode of religious worship."Malta is a popular tourist destination with its warm climate, numerous recreational areas, architectural and historical monuments, including three UNESCO World Heritage Sites: Hypogeum of Ħal-Saflieni and seven megalithic temples which are some of the oldest free-standing structures in the world.
The origin of the name Malta is uncertain, the modern-day variation is derived from the Maltese language. The most common etymology is that the word Malta is derived from the Greek word μέλι, meli, "honey"; the ancient Greeks called the island Μελίτη meaning "honey-sweet" for Malta's unique production of honey. The Romans called the island Melita, which can be considered either a latinisation of the Greek Μελίτη or the adaptation of the Doric Greek pronunciation of the same word Μελίτα; this spelling is found in the New Testament. Another conjecture suggests that the word Malta comes from the Phoenician word Maleth, "a haven", or'port' in reference to Malta's many bays and coves. Few other etymological mentions appear in classical literature, with the term Malta appearing in its present form in the Antonine Itinerary. Malta has been inhabited from around 5900 BC, since the arrival of settlers from the island of Sicily. A significant prehistoric Neolithic culture marked by Megalithic structures, which date back to c. 3600 BC, existed on the islands, as evidenced by the temples of Mnajdra and others.
The Phoenicians colonised Malta between 800 -- 700 BC, bringing their Semitic culture. They used the islands as an outpost from which they expanded sea explorations and trade in the Mediterranean until their successors, the Carthaginians, were ousted by the Romans in 216 BC with the help of the Maltese inhabitants, under whom Malta became a municipium. After a period of Byzantine rule and a probable sack by the Vandals, the islands were invaded by the Aghlabids in AD 870; the fate of the population after the Arab invasion is unclear but it seems the islands may have been depopulated and were to have been repopulated in the beginning of the second millennium by settlers from Arab-ruled Sicily who spoke Siculo-Arabic. The Muslim rule was ended by the Normans who conquered the island in 1091; the islands were re-Christianised by 1249. The islands were part of the Kingdom of Sicily until 1530, were controlled by the Capetian House of Anjou. In 1530 Charles I of Spain gave the Maltese islands to the Order of Knights of the Hospital of St John of Jerusalem in perpetual lease.
The French under Napoleon took hold of the Maltese islands in 1798, although with the aid of the British the Maltese were able to oust French control two years later. The inhabitants subsequently asked Britain to assume sovereignty over the islands under the conditions laid out in a Declaration of Rights, stating that "his Majesty has no right to cede these Islands to any power...if he chooses to withdraw his protection, abandon his sovereignty, the right of electing another sovereign, or of the governing of these Islands, belongs to us, the inhabitants and aborigines alone, without control." As part of the Treaty of Paris in 1814, Malta became a British colony rejecting an attempted integration with the United Kingdom in 1956. Malta became independent on 21 September 1964. Under its 1964 constitution
Drywall is a panel made of calcium sulfate dihydrate, with or without additives extruded between thick sheets of facer and backer paper, used in the construction of interior walls and ceilings. The plaster is mixed with fiber, foaming agent, various additives that can reduce mildew and water absorption. Drywall construction became prevalent in North America as a time and labor saving alternative to traditional lath and plaster; the first plasterboard plant in the UK was opened in 1888 in Kent. Sackett Board was invented in 1894 by Augustine Sackett and Fred Kane, graduates of Rensselaer Polytechnic Institute, it was made by layering. Sheets were 36 by 36 by 1⁄4 inch thick with open edges. Gypsum board evolved between 1910 and 1930 beginning with wrapped board edges and elimination of the two inner layers of felt paper in favor of paper-based facings. In 1910 United States Gypsum Corporation bought Sackett Plaster Board Company and by 1917 introduced Sheetrock. Providing efficiency of installation, it was developed additionally as a measure of fire resistance.
Air entrainment technology made boards lighter and less brittle, joint treatment materials and systems evolved. Gypsum lath was an early substrate for plaster. An alternative to traditional wood or metal lath, it was a panel made up of compressed gypsum plaster board, sometimes grooved or punched with holes to allow wet plaster to key into its surface; as it evolved, it was faced with paper impregnated with gypsum crystals that bonded with the applied facing layer of plaster. In 1936 US Gypsum trademarked ROCKLATH for their gypsum lath product. In 2002 the European Commission imposed fines totaling €478 million on the companies Lafarge, BPB, Knauf and Gyproc Benelux, which had operated a cartel on the market which affected 80% of consumers in France, the UK, Germany and the Benelux countries. A wallboard panel consists of a layer of gypsum plaster sandwiched between two layers of paper; the raw gypsum, CaSO4·2 H2O, is heated to drive off the water slightly rehydrated to produce the hemihydrate of calcium sulfate.
The plaster is mixed with fibre, foaming agent, finely ground gypsum crystal as an accelerator, EDTA, starch or other chelate as a retarder, various additives that may decrease mildew and increase fire resistance, wax emulsion or silanes for lower water absorption. The board is formed by sandwiching a core of the wet mixture between two sheets of heavy paper or fibreglass mats; when the core sets it is dried in a large drying chamber, the sandwich becomes rigid and strong enough for use as a building material. Drying chambers use natural gas today. To dry 1 MSF of wallboard, between 1,750,000 and 2,490,000 BTU is required. Organic dispersants/plasticisers are used so the slurry will flow during manufacture, to reduce the water and hence the drying time. Coal-fired power stations include devices called scrubbers to remove sulphur from their exhaust emissions; the sulphur is absorbed by powdered limestone in a process called flue-gas desulphurization, which produces a number of new substances. One is called "FGD gypsum".
This is used in drywall construction in the United States and elsewhere. Drywall panels in the United States are manufactured in 48,-54,-and-96-inch wide panels in varying lengths to suit the application, though 48-inch is by far the most common width. Lengths up to 16 feet are available, though the most common length is 8 feet. Common panel thicknesses are 1⁄2 and 5⁄8 inch, 1⁄4, 3⁄8, 3⁄4, 1 inch thicknesses are used in specific applications. In Europe, most plasterboard is made in 120-centimetre-wide sheets, though 60-and-90-centimetre-wide sheets are made. Plasterboard 120 cm wide is most made in 240 centimetres lengths, though 250, 260, 270, 280, 300 centimetres or longer are available. Thicknesses of plasterboard available are 9.5 to 25 millimetres. Plasterboard is made with one of three different edge treatments: tapered edge, where the long edges of the board are tapered with a wide bevel at the front to allow for jointing materials to be finished flush with the main board face. However, four-side chamfered drywall is not offered by major UK manufacturers for general use.
The term plasterboard is used in Australia and New Zealand, in the latter country it is known as Gibraltar board. Panels are sold in 1200 × 2400 mm, 1200 × 4800 mm, 1200 × 6000 mm sheets. Sheets are secured to either a timber or cold-formed steel frames anywhere from 150 to 300 mm centres along the beam and 400 to 600 mm across members. Various companies, such as Boral and CSR, manufacture plasterboard under various brand names including Gyprock; as an alternative to a week-long plaster application, an entire house can be drywalled in one or two days by two experienced drywallers, drywall is easy enough to use that it can
A building, or edifice, is a structure with a roof and walls standing more or less permanently in one place, such as a house or factory. Buildings come in a variety of sizes and functions, have been adapted throughout history for a wide number of factors, from building materials available, to weather conditions, land prices, ground conditions, specific uses, aesthetic reasons. To better understand the term building compare the list of nonbuilding structures. Buildings serve several societal needs – as shelter from weather, living space, privacy, to store belongings, to comfortably live and work. A building as a shelter represents a physical division of the outside. Since the first cave paintings, buildings have become objects or canvasses of much artistic expression. In recent years, interest in sustainable planning and building practices has become an intentional part of the design process of many new buildings; the word building is the act of making it. As a noun, a building is'a structure that has a roof and walls and stands more or less permanently in one place'.
In the broadest interpretation a fence or wall is a building. However, the word structure is used more broadly than building including natural and man-made formations and does not have walls. Structure is more to be used for a fence. Sturgis' Dictionary included that " differs from architecture in excluding all idea of artistic treatment; as a verb, building is the act of construction. Structural height in technical usage is the height to the highest architectural detail on building from street-level. Depending on how they are classified and masts may or may not be included in this height. Spires and masts used as antennas are not included; the definition of a low-rise vs. a high-rise building is a matter of debate, but three storeys or less is considered low-rise. A report by Shinichi Fujimura of a shelter built 500 000 years ago is doubtful since Fujimura was found to have faked many of his findings. Supposed remains of huts found at the Terra Amata site in Nice purportedly dating from 200 000 to 400 000 years ago have been called into question.
There is clear evidence of homebuilding from around 18 000 BC. Buildings became common during the Neolithic. Single-family residential buildings are most called houses or homes. Multi-family residential buildings containing more than one dwelling unit are called a duplex or an apartment building. A condominium is an apartment rather than rents. Houses may be built in pairs, in terraces where all but two of the houses have others either side. Houses which were built as a single dwelling may be divided into apartments or bedsitters. Building types may range from huts to multimillion-dollar high-rise apartment blocks able to house thousands of people. Increasing settlement density in buildings is a response to high ground prices resulting from many people wanting to live close to work or similar attractors. Other common building materials are concrete or combinations of either of these with stone. Residential buildings have different names for their use depending if they are seasonal include holiday cottage or timeshare.
If the residents are in need of special care such as a nursing home, orphanage or prison. Many people lived in communal buildings called longhouses, smaller dwellings called pit-houses and houses combined with barns sometimes called housebarns. Buildings are defined to be substantial, permanent structures so other dwelling forms such as houseboats and motorhomes are dwellings but not buildings. Sometimes a group of inter-related builds are referred to as a complex – for example a housing complex, educational complex, hospital complex, etc; the practice of designing and operating buildings is most a collective effort of different groups of professionals and trades. Depending on the size and purpose of a particular building project, the project team may include: A real estate developer who secures funding for the project. Other possible design Engineer specialists may be involved such as Fire, facade engineers, building physics, Telecomms, AV (Audio V
A chimney is an architectural ventilation structure made of masonry, clay or metal that isolates hot toxic exhaust gases or smoke produced by a boiler, furnace, incinerator or fireplace from human living areas. Chimneys are vertical, or as near as possible to vertical, to ensure that the gases flow smoothly, drawing air into the combustion in what is known as the stack, or chimney effect; the space inside a chimney is called the flue. Chimneys are adjacent to large industrial refineries, fossil fuel combustion facilities or part of buildings, steam locomotives and ships. In the United States, the term'Smokestack industry' refers to the environmental impacts of burning fossil fuels by industrial society including the electric industry during its earliest history; the term smokestack is used when referring to locomotive chimneys or ship chimneys, the term funnel can be used. The height of a chimney influences its ability to transfer flue gases to the external environment via stack effect. Additionally, the dispersion of pollutants at higher altitudes can reduce their impact on the immediate surroundings.
The dispersion of pollutants over a greater area can reduce their concentrations and facilitate compliance with regulatory limits. Romans used tubes inside the walls to draw smoke out of bakeries but chimneys only appeared in large dwellings in northern Europe in the 12th century; the earliest extant example of an English chimney is at the keep of Conisbrough Castle in Yorkshire, which dates from 1185 AD. However, they did not become common in houses until the 17th centuries. Smoke hoods were an early method of collecting the smoke into a chimney. Another step in the development of chimneys was the use of built in ovens which allowed the household to bake at home. Industrial chimneys became common in the late 18th century. Chimneys in ordinary dwellings were first built of plaster or mud. Since chimneys have traditionally been built of brick or stone, both in small and large buildings. Early chimneys were of a simple brick construction. Chimneys were constructed by placing the bricks around tile liners.
To control downdrafts, venting caps with a variety of designs are sometimes placed on the top of chimneys. In the 18th and 19th centuries, the methods used to extract lead from its ore produced large amounts of toxic fumes. In the north of England, long near-horizontal chimneys were built more than 3 km long, which terminated in a short vertical chimney in a remote location where the fumes would cause less harm. Lead and silver deposits formed on the inside of these long chimneys, periodically workers would be sent along the chimneys to scrape off these valuable deposits; as a result of the limited ability to handle transverse loads with brick, chimneys in houses were built in a "stack", with a fireplace on each floor of the house sharing a single chimney with such a stack at the front and back of the house. Today's central heating systems have made chimney placement less critical, the use of non-structural gas vent pipe allows a flue gas conduit to be installed around obstructions and through walls.
In fact, most modern high-efficiency heating appliances do not require a chimney. Such appliances are installed near an external wall, a noncombustible wall thimble allows a vent pipe to run directly through the external wall. On a pitched roof where a chimney penetrates a roof, flashing is used to seal up the joints; the down-slope piece is called an apron, the sides receive step flashing and a cricket is used to divert water around the upper side of the chimney underneath the flashing. Industrial chimneys are referred to as flue gas stacks and are external structures, as opposed to those built into the wall of a building, they are located adjacent to a steam-generating boiler or industrial furnace and the gases are carried to them with ductwork. Today the use of reinforced concrete has entirely replaced brick as a structural component in the construction of industrial chimneys. Refractory bricks are used as a lining if the type of fuel being burned generates flue gases containing acids. Modern industrial chimneys sometimes consist of a concrete windshield with a number of flues on the inside.
The 300 m chimney at Sasol Three consists of a 26 m diameter windshield with four 4.6 metre diameter concrete flues which are lined with refractory bricks built on rings of corbels spaced at 10 metre intervals. The reinforced concrete can be sliding formwork; the height is to ensure the pollutants are dispersed over a wider area to meet legal or other safety requirements. A flue liner is a secondary barrier in a chimney that protects the masonry from the acidic products of combustion, helps prevent flue gas from entering the house, reduces the size of an oversized flue. Since the 1950s, building codes in many locations require newly built chimneys to have a flue liner. Chimneys built without a liner can have a liner added, but the type of liner needs to match the type of appliance it services. Flue liners may be concrete tile, metal, or poured in place concrete. Clay tile flue liners are common in the United States, although it is the only liner that does not meet Underwriters Laboratories 1777 approval and they have problems such as cracked tiles and improper installation.
Clay tiles are about 2 feet long, available in various sizes and shapes, are installed in new construction as the chimney is built. A refractory cement is used between each tile. Metal liners may be stainless steel, aluminum, or galvanized iron and may be flexible or rigid pipes. Stainless stee
Recycling is the process of converting waste materials into new materials and objects. It is an alternative to "conventional" waste disposal that can save material and help lower greenhouse gas emissions. Recycling can prevent the waste of useful materials and reduce the consumption of fresh raw materials, thereby reducing: energy usage, air pollution, water pollution. Recycling is a key component of modern waste reduction and is the third component of the "Reduce and Recycle" waste hierarchy. Thus, recycling aims at environmental sustainability by substituting raw material inputs into and redirecting waste outputs out of the economic system. There are some ISO standards related to recycling such as ISO 15270:2008 for plastics waste and ISO 14001:2015 for environmental management control of recycling practice. Recyclable materials include many kinds of glass, cardboard, plastic, textiles and electronics; the composting or other reuse of biodegradable waste—such as food or garden waste—is a form of recycling.
Materials to be recycled are either delivered to a household recycling center or picked up from curbside bins sorted and reprocessed into new materials destined for manufacturing new products. In the strictest sense, recycling of a material would produce a fresh supply of the same material—for example, used office paper would be converted into new office paper or used polystyrene foam into new polystyrene. However, this is difficult or too expensive, so "recycling" of many products or materials involves their reuse in producing different materials instead. Another form of recycling is the salvage of certain materials from complex products, either due to their intrinsic value, or due to their hazardous nature. Recycling has been a common practice for most of human history, with recorded advocates as far back as Plato in the fourth century BC. During periods when resources were scarce and hard to come by, archaeological studies of ancient waste dumps show less household waste —implying more waste was being recycled in the absence of new material.
In pre-industrial times, there is evidence of scrap bronze and other metals being collected in Europe and melted down for perpetual reuse. Paper recycling was first recorded in 1031. In Britain dust and ash from wood and coal fires was collected by "dustmen" and downcycled as a base material used in brick making; the main driver for these types of recycling was the economic advantage of obtaining recycled feedstock instead of acquiring virgin material, as well as a lack of public waste removal in more densely populated areas. In 1813, Benjamin Law developed the process of turning rags into "shoddy" and "mungo" wool in Batley, Yorkshire; this material combined recycled fibers with virgin wool. The West Yorkshire shoddy industry in towns such as Batley and Dewsbury lasted from the early 19th century to at least 1914. Industrialization spurred demand for affordable materials. Railroads both purchased and sold scrap metal in the 19th century, the growing steel and automobile industries purchased scrap in the early 20th century.
Many secondary goods were collected and sold by peddlers who scoured dumps and city streets for discarded machinery, pots and other sources of metal. By World War I, thousands of such peddlers roamed the streets of American cities, taking advantage of market forces to recycle post-consumer materials back into industrial production. Beverage bottles were recycled with a refundable deposit at some drink manufacturers in Great Britain and Ireland around 1800, notably Schweppes. An official recycling system with refundable deposits was established in Sweden for bottles in 1884 and aluminum beverage cans in 1982. New chemical industries created in the late 19th century both invented new materials and promised to transform valueless into valuable materials. Proverbially, you could not make a silk purse of a sow's ear—until the US firm Arthur D. Little published in 1921 "On the Making of Silk Purses from Sows' Ears", its research proving that when "chemistry puts on overalls and gets down to business... new values appear.
New and better paths are opened to reach the goals desired."Recycling was a major issue for governments throughout World War II. Financial constraints and significant material shortages due to war efforts made it necessary for countries to reuse goods and recycle materials; these resource shortages caused by the world wars, other such world-changing occurrences encouraged recycling. The struggles of war claimed much of the material resources available, leaving little for the civilian population, it became necessary for most homes to recycle their waste, as recycling offered an extra source of materials allowing people to make the most of what was available to them. Recycling household materials meant a better chance of victory. Massive government promotion campaigns, such as the National Salvage Campaign in Britain and the Salvage for Victory campaign in the United States, were carried out on the home front in every combative nation, urging citizens to donate metal, rags, r
A wrecking ball is a heavy steel ball hung from a crane, used for demolishing large buildings. It was most in use during the 1950s and 1960s. Several wrecking companies claim to have invented the wrecking ball. An early documented use was in the breaking up of the SS Great Eastern in 1888–1889, by Henry Bath and Co, at Rock Ferry on the River Mersey. In 1999, the wrecking ball was described as "one of the most common forms of large-scale coarse demolition." Although the wrecking ball is still the most efficient way to raze a concrete frame structure, its use is decreasing. With the invention of hydraulic excavators and other machinery, the wrecking ball has become less common at demolition sites as its working efficiency is less than that of high reach excavators. Modern wrecking balls have had a slight re-shaping, with the metal sphere changed into a pear shape with a portion of the top cut off; this shape allows the ball to be more pulled back through a roof or concrete slab after it has broken through.
Wrecking balls range from about 1,000 pounds to around 12,000 pounds. The ball is made from forged steel. To demolish roofs and other horizontal spans, the ball is suspended by a length of steel chain attached to the lifting hook of a crane boom above the structure, the rope drum clutch is released and the ball is allowed to free-fall onto the structure. To demolish walls the ball is suspended at the desired height from a crane boom and a secondary steel rope pulls the ball toward the crane cab; the lateral rope drum clutch is released and the ball swings as a pendulum to strike the structure. Another method for lateral demolition is to pivot the crane boom to accelerate the ball toward the target; this is repeated as needed until the structure is broken down into debris that can be loaded and hauled away. The demolition action is carried out through the kinetic energy of the ball. Demolition work has been carried out using a 5,500-pound wrecking ball suspended from a Kaman K-MAX helicopter; the same mechanism is applied to quarrying rock where an excavator lifts and releases a loose ball onto large rocks to reduce them to manageable size.
The advancement of technology led to the development and use of blasting charges, safer than dynamite and more efficient or practical than wrecking balls, to destroy buildings. The most common use of blasting charges is to implode a building. Wrecking balls are more to cause collateral damage, because it is difficult to control the swing of the ball. However, wrecking balls are still used when other demolition methods may not be practical, due for example to local environmental issues or the presence of hazardous building materials such as asbestos or lead. Byles, Jeff. Rubble: unearthing the history of demolition. New York: Harmony Books. ISBN 140005057X. Diven, Richard J. and Mark Shaurette. Demolition: practices and management. Purdue University Press, West Lafayette, Indiana. ISBN 1557535671. Liss, Helene. Demolition: the art of demolishing, imploding, toppling & razing. New York: Black Dog & Leventhal: Distributed by Workman Pub. Co. ISBN 1579121497. Media related to Wrecking balls at Wikimedia Commons
Excavators are heavy construction equipment consisting of a boom, dipper and cab on a rotating platform known as the "house". The house sits atop an undercarriage with wheels, they are a natural progression from the steam shovels and mistakenly called power shovels. All movement and functions of a hydraulic excavator are accomplished through the use of hydraulic fluid, with hydraulic cylinders and hydraulic motors. Due to the linear actuation of hydraulic cylinders, their mode of operation is fundamentally different from cable-operated excavators which use winches and steel ropes to accomplish the movements. Excavators are called diggers, JCBs, mechanical shovels, or 360-degree excavators. Tracked excavators are sometimes called "trackhoes" by analogy to the backhoe. In the UK, wheeled excavators are sometimes known as "rubber ducks." Excavators are used in many ways: Digging of trenches, foundations Material handling Brush cutting with hydraulic saw and mower attachments Forestry work Forestry mulching Construction Demolition with hydraulic claw and breaker attachments General grading/landscaping Mining but not only open-pit mining River dredging Driving piles, in conjunction with a pile driver Drilling shafts for footings and rock blasting, by use of an auger or hydraulic drill attachment Snow removal with snowplow and snow blower attachments Modern hydraulic excavators come in a wide variety of sizes.
The smaller ones are called compact excavators. For example, Caterpillar's smallest mini-excavator has 13 hp. Hydraulic excavators couple engine power to three hydraulic pumps rather than to mechanical drivetrains; the two main pumps supply oil at high pressure for the arms, swing motor, track motors and accessories while the third is a lower pressure pump for pilot control of the spool valves. The 3 pumps used in excavators consist of 2 variable displacement piston pumps and a gear pump; the arrangement of the pumps in the excavator unit changes with different manufacturers using different formats. The two main sections of an excavator are the house; the undercarriage includes the blade, track frame, final drives, which have a hydraulic motor and gearing providing the drive to the individual tracks. The house includes the operator cab, engine and hydraulic oil tanks; the house attaches to the undercarriage by way of a center pin. High pressure oil is supplied to the tracks' hydraulic motors through a hydraulic swivel at the axis of the pin, allowing the machine to slew 360° unhindered.
The main boom attaches to the house, can be one of several different configurations: Most are mono booms: these have no movement apart from straight up and down. Some others have a knuckle boom which can move left and right in line with the machine. Another option is a hinge at the base of the boom allowing it to hydraulically pivot up to 180° independent to the house. There are triple-articulated booms. Attached to the end of the boom is the stick; the stick provides the digging force needed to pull the bucket through the ground. The stick length is optional depending whether break-out power is required. On the end of the stick is a bucket. A wide, large capacity bucket with a straight cutting edge is used for cleanup and levelling or where the material to be dug is soft, teeth are not required. A general purpose bucket is smaller and has hardened side cutters and teeth used to break through hard ground and rocks. Buckets have numerous sizes for various applications. There are many other attachments which are available to be attached to the excavator for boring, crushing, lifting, etc.
Excavators in Scandinavia feature a tiltrotator which allows attachments rotate 360 degrees and tilt +/- 45 degrees, in order to increase the flexibility and precision of the excavator. Before the 1990s, all excavators had a long or conventional counterweight that hung off the rear of the machine to provide more digging force and lifting capacity; this became a nuisance. In 1993 Yanmar launched the world's first Zero Tail Swing excavator, which allows the counterweight to stay inside the width of the tracks as it slews, thus being safer and more user friendly when used in a confined space; this type of machine is now used throughout the world. There are two main types of "Control" configuration use in excavators to control the boom and bucket, both of which spread the four main digging controls between two x-y joysticks; this allows a skilled operator to control all four functions simultaneously. The most popular configuration in the US is the SAE controls configuration while in other parts of the world, the ISO control configuration is more common.
Some manufacturers such as Takeuchi have switches that allow the operator to select which control configuration to use. Hydraulic excavator capabilities have expanded far beyond excavation tasks with buckets. With the advent of hydraulic-powered attachments such as a breaker, a grapple or an auger, the excavator is used in many applications other