|
Boat Operations 150202-M-GR217-049
A boat is a watercraft of a large range of types and sizes, but generally smaller than a ship, which is distinguished by its larger size, shape, cargo or passenger capacity, or its ability to carry boats. Small boats are typically found on inland waterways such as rivers and lakes, or in protected coastal areas. However, some boats, such as the whaleboat, were intended for use in an offshore environment. In modern naval terms, a boat is a vessel small enough to be carried aboard a ship. Boats vary in proportion and construction methods with their intended purpose, available materials, or local traditions. Canoes have been used since prehistoric times and remain in use throughout the world for transportation, fishing, and sport. Fishing boats vary widely in style partly to match local conditions. Pleasure craft used in recreational boating include ski boats, pontoon boats, and sailboats. House boats may be used for vacationing or long-term residence. Lighters are us ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Motorboat At Kankaria Lake
A motorboat, speedboat or powerboat is a boat that is exclusively powered by an engine. Some motorboats are fitted with inboard engines, others have an outboard motor installed on the rear, containing the internal combustion engine, the gearbox and the propeller in one portable unit. An inboard-outboard contains a hybrid of an inboard and an outboard, where the internal combustion engine is installed inside the boat, and the gearbox and propeller are outside. There are two configurations of an inboard, V-drive and direct drive. A direct drive has the powerplant mounted near the middle of the boat with the propeller shaft straight out the back, where a V-drive has the powerplant mounted in the back of the boat facing backwards having the shaft go towards the front of the boat then making a ''V'' towards the rear. Overview A motorboat has one or more engines that propel the vessel over the top of the water. Boat engines vary in shape, size, and type. Engines are installed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pedalo
A pedalo (British English) or paddle boat (U.S., Canadian, and Australian English) is a human-powered watercraft propelled by the action of pedals turning a paddle wheel. Description A pedalo is a human-powered watercraft propelled by the turning of a paddle wheel. The wheel is turned by people of rotating the pedals of the craft. The paddle wheel of a pedalo is a smaller version of that used by a paddle steamer. Use Pedalos, being particularly suited to calm waters, are often hired out for use on ponds and small lakes in urban parks. Designs The earliest record of a pedalo is perhaps Leonardo da Vinci Leonardo di ser Piero da Vinci (15 April 14522 May 1519) was an Italian polymath of the High Renaissance who was active as a painter, Drawing, draughtsman, engineer, scientist, theorist, sculptor, and architect. While his fame initially res ...'s diagram of a craft driven by two pedals. Typically, a two-seat pedalo has two sets of pedals side-by-side, designed to b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flores
Flores is one of the Lesser Sunda Islands, a group of islands in the eastern half of Indonesia. Including the Komodo Islands off its west coast (but excluding the Solor Archipelago to the east of Flores), the land area is 15,530.58 km2, and the population was 1,878,875 in the 2020 Census (including various offshore islands); the official estimate as at mid 2021 was 1,897,550. The largest towns are Maumere and Ende. The name ''Flores'' is the Portuguese and Spanish word for "Flowers". Flores is located east of Sumbawa and the Komodo islands, and west of the Solor Islands and the Alor Archipelago. To the southeast is Timor. To the south, across the Sumba Strait, is Sumba island and to the north, beyond the Flores Sea, is Sulawesi. Among all islands containing Indonesian territory, Flores is the 10th most populous after Java, Sumatra, Borneo ( Kalimantan), Sulawesi, New Guinea, Bali, Madura, Lombok, and Timor and also the 10th biggest island of Indonesia. Until the arr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crete
Crete ( el, Κρήτη, translit=, Modern: , Ancient: ) is the largest and most populous of the Greek islands, the 88th largest island in the world and the fifth largest island in the Mediterranean Sea, after Sicily, Sardinia, Cyprus, and Corsica. Crete rests about south of the Greek mainland, and about southwest of Anatolia. Crete has an area of and a coastline of 1,046 km (650 mi). It bounds the southern border of the Aegean Sea, with the Sea of Crete (or North Cretan Sea) to the north and the Libyan Sea (or South Cretan Sea) to the south. Crete and a number of islands and islets that surround it constitute the Region of Crete ( el, Περιφέρεια Κρήτης, links=no), which is the southernmost of the 13 top-level administrative units of Greece, and the fifth most populous of Greece's regions. Its capital and largest city is Heraklion, on the north shore of the island. , the region had a population of 636,504. The Dodecanese are located to the no ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Early Human Migrations
Early human migrations are the earliest migrations and expansions of archaic and modern humans across continents. They are believed to have begun approximately 2 million years ago with the early expansions out of Africa by '' Homo erectus''. This initial migration was followed by other archaic humans including '' H. heidelbergensis'', which lived around 500,000 years ago and was the likely ancestor of Denisovans and Neanderthals as well as modern humans. Early hominids had likely crossed land bridges that have now sunk. Within Africa, '' Homo sapiens'' dispersed around the time of its speciation, roughly 300,000 years ago. The recent African origin paradigm suggests that the anatomically modern humans outside of Africa descend from a population of ''Homo sapiens'' migrating from East Africa roughly 70–50,000 years ago and spreading along the southern coast of Asia and to Oceania by about 50,000 years ago. Modern humans spread across Europe about 40,000 years ago. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pre-historic
Prehistory, also known as pre-literary history, is the period of human history between the use of the first stone tools by hominins 3.3 million years ago and the beginning of recorded history with the invention of writing systems. The use of symbols, marks, and images appears very early among humans, but the earliest known writing systems appeared 5000 years ago. It took thousands of years for writing systems to be widely adopted, with writing spreading to almost all cultures by the 19th century. The end of prehistory therefore came at very different times in different places, and the term is less often used in discussing societies where prehistory ended relatively recently. In the early Bronze Age, Sumer in Mesopotamia, the Indus Valley Civilisation, and ancient Egypt were the first civilizations to develop their own scripts and to keep historical records, with their neighbors following. Most other civilizations reached the end of prehistory during the following Iron Age. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Strait
A strait is an oceanic landform connecting two seas or two other large areas of water. The surface water generally flows at the same elevation on both sides and through the strait in either direction. Most commonly, it is a narrow ocean channel that lies between two land masses. Some straits are not navigable, for example because they are either too narrow or too shallow, or because of an unnavigable reef or archipelago. Straits are also known to be loci for sediment accumulation. Usually, sand-size deposits occur on both the two opposite strait exits, forming subaqueous fans or deltas. Terminology The terms ''channel'', ''pass'', or ''passage'' can be synonymous and used interchangeably with ''strait'', although each is sometimes differentiated with varying senses. In Scotland, ''firth'' or ''Kyle'' are also sometimes used as synonyms for strait. Many straits are economically important. Straits can be important shipping routes and wars have been fought for control of them. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homo Erectus
''Homo erectus'' (; meaning "upright man") is an extinct species of archaic human from the Pleistocene, with its earliest occurrence about 2 million years ago. Several human species, such as '' H. heidelbergensis'' and '' H. antecessor'' — with the former generally considered to have been the ancestor to Neanderthals, Denisovans, and modern humans — appear to have evolved from ''H. erectus''. Its specimens are among the first recognizable members of the genus ''Homo''. ''H. erectus'' was the first human ancestor to spread throughout Eurasia, with a continental range extending from the Iberian Peninsula to Java. Asian populations of ''H. erectus'' may be ancestral to '' H. floresiensis'' and possibly to '' H. luzonensis''. The last known population of ''H. erectus'' is '' H. e. soloensis'' from Java, around 117,000–108,000 years ago. ''H. erectus'' had a more modern gait and body proportions, and was the first human species to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silver Model Of A Boat, Tomb PG 789, Royal Cemetery Of UR, 2600-2500 BCE
Silver is a chemical element with the symbol Ag (from the Latin ', derived from the Proto-Indo-European ''h₂erǵ'': "shiny" or "white") and atomic number 47. A soft, white, lustrous transition metal, it exhibits the highest electrical conductivity, thermal conductivity, and reflectivity of any metal. The metal is found in the Earth's crust in the pure, free elemental form ("native silver"), as an alloy with gold and other metals, and in minerals such as argentite and chlorargyrite. Most silver is produced as a byproduct of copper, gold, lead, and zinc Refining (metallurgy), refining. Silver has long been valued as a precious metal. Silver metal is used in many bullion coins, sometimes bimetallism, alongside gold: while it is more abundant than gold, it is much less abundant as a native metal. Its purity is typically measured on a per-mille basis; a 94%-pure alloy is described as "0.940 fine". As one of the seven metals of antiquity, silver has had an enduring role in most h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electric Motor
An electric motor is an Electric machine, electrical machine that converts electrical energy into mechanical energy. Most electric motors operate through the interaction between the motor's magnetic field and electric current in a Electromagnetic coil, wire winding to generate force in the form of torque applied on the motor's shaft. An electric generator is mechanically identical to an electric motor, but operates with a reversed flow of power, converting mechanical energy into electrical energy. Electric motors can be powered by direct current (DC) sources, such as from batteries, or rectifiers, or by alternating current (AC) sources, such as a power grid, Inverter (electrical), inverters or electrical generators. Electric motors may be classified by considerations such as power source type, construction, application and type of motion output. They can be powered by AC or DC, be Brushed motor, brushed or Brushless motor, brushless, single-phase, Two-phase electric power, two-p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diesel Engine
The diesel engine, named after Rudolf Diesel, is an internal combustion engine in which ignition of the fuel is caused by the elevated temperature of the air in the cylinder due to mechanical compression; thus, the diesel engine is a so-called compression-ignition engine (CI engine). This contrasts with engines using spark plug-ignition of the air-fuel mixture, such as a petrol engine (gasoline engine) or a gas engine (using a gaseous fuel like natural gas or liquefied petroleum gas). Diesel engines work by compressing only air, or air plus residual combustion gases from the exhaust (known as exhaust gas recirculation (EGR)). Air is inducted into the chamber during the intake stroke, and compressed during the compression stroke. This increases the air temperature inside the cylinder to such a high degree that atomised diesel fuel injected into the combustion chamber ignites. With the fuel being injected into the air just before combustion, the dispersion of the fuel is une ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gasoline Engine
A petrol engine (gasoline engine in American English) is an internal combustion engine designed to run on petrol (gasoline). Petrol engines can often be adapted to also run on fuels such as liquefied petroleum gas and ethanol blends (such as ''E10'' and ''E85''). Most petrol engines use spark ignition, unlike diesel engines which typically use compression ignition. Another key difference to diesel engines is that petrol engines typically have a lower compression ratio. Design Thermodynamic cycle Most petrol engines use either the four-stroke Otto cycle or the two-stroke cycle. Petrol engines have also been produced using the Miller cycle and Atkinson cycle. Layout Most petrol-powered piston engines are straight engines or V engines. However, flat engines, W engines and other layouts are sometimes used. Wankel engines are classified by the number of rotors used. Compression ratio Cooling Petrol engines are either air-cooled or water-cooled. Ignition Petrol en ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
.jpg "Click for more on -> Pedalo")
