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Rock-dumping Vessels
Rock dumping vessels are a category of watercraft that exist for the purpose of dumping rocks on the seabed. They are able to transport and dump rocks of variable sizes. The vessels range from large bulk-carrier style vessels, able to carry out precision operations using fallpipes, to smaller deck-loading vessels mainly used for erosion remediation. Almost all such vessels are fitted with a dynamic positioning system, which makes it possible to position rocks very accurately. Large cranes or fall pipes are used to dump the rocks from the vessels. Side-discharging by means of crane is usually done in shallow waters, while fall pipes are more commonly used in deep-water rock-dumping operations. The most common need for rock dumpers is to provide protection to previously laid pipelines in areas where they may be damaged by fishing gear. Pipelines at risk are not trenched, but remain on the seabed. There are a number of protection methods for such pipelines, including the placement ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stone Dumping Vessel Berghaus
In geology, rock (or stone) is any naturally occurring solid mass or aggregate of minerals or mineraloid matter. It is categorized by the minerals included, its chemical composition, and the way in which it is formed. Rocks form the Earth's outer solid layer, the crust, and most of its interior, except for the liquid outer core and pockets of magma in the asthenosphere. The study of rocks involves multiple subdisciplines of geology, including petrology and mineralogy. It may be limited to rocks found on Earth, or it may include planetary geology that studies the rocks of other celestial objects. Rocks are usually grouped into three main groups: igneous rocks, sedimentary rocks and metamorphic rocks. Igneous rocks are formed when magma cools in the Earth's crust, or lava cools on the ground surface or the seabed. Sedimentary rocks are formed by diagenesis and lithification of sediments, which in turn are formed by the weathering, transport, and deposition of existing rocks. M ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Watercraft
Any vehicle used in or on water as well as underwater, including boats, ships, hovercraft and submarines, is a watercraft, also known as a water vessel or waterborne vessel. A watercraft usually has a propulsive capability (whether by sail, oar, paddle, or engine) and hence is distinct from a stationary device, such as a pontoon, that merely floats. Types Most watercraft may be described as either a ship or a boat. However, numerous items, including surfboards, underwater robots, seaplanes and torpedoes, may be considered neither ships nor boats. Although ships are typically larger than boats, the distinction between those two categories is not one of size per se. *Ships are typically large ocean-going vessels; whereas boats are smaller, and typically travel most often on inland or coastal waters. *A rule of thumb says "a boat can fit on a ship, but a ship can't fit on a boat", and a ship ''usually'' has sufficient size to carry its own boats, such as lifeboats, dingh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dynamic Positioning
Dynamic positioning (DP) is a computer-controlled system to automatically maintain a vessel's position and heading by using its own propellers and thrusters. Position reference sensors, combined with wind sensors, motion sensors and gyrocompasses, provide information to the computer pertaining to the vessel's position and the magnitude and direction of environmental forces affecting its position. Examples of vessel types that employ DP include ships and semi-submersible mobile offshore drilling units (MODU), oceanographic research vessels, cable layer ships and cruise ships. The computer program contains a mathematical model of the vessel that includes information pertaining to the wind and current drag of the vessel and the location of the thrusters. This knowledge, combined with the sensor information, allows the computer to calculate the required steering angle and thruster output for each thruster. This allows operations at sea where mooring or anchoring is not feasible du ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pipeline Transport
Pipeline transport is the long-distance transportation of a liquid or gas through a system of pipes—a pipeline—typically to a market area for consumption. The latest data from 2014 gives a total of slightly less than of pipeline in 120 countries of the world. The United States had 65%, Russia had 8%, and Canada had 3%, thus 76% of all pipeline were in these three countries. ''Pipeline and Gas Journals worldwide survey figures indicate that of pipelines are planned and under construction. Of these, represent projects in the planning and design phase; reflect pipelines in various stages of construction. Liquids and gases are transported in pipelines, and any chemically stable substance can be sent through a pipeline. Pipelines exist for the transport of crude and refined petroleum, fuels – such as oil, natural gas and biofuels – and other fluids including sewage, slurry, water, beer, hot water or steam for shorter distances. Pipelines are useful for transporting water ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fishing Tackle
Fishing tackle is the equipment used by anglers when fishing. Almost any equipment or gear used in fishing can be called fishing tackle, examples being hooks, lines, baits/ lures, rods, reels, floats, sinkers/ feeders, nets, stringers/ keepnets/ livewells, spears, gaffs, traps, waders and tackle boxes, as well as any wire, snaps, beads, spoons, blades, spinners, clevises and tools that make it easy to tie knots. Gear that is attached to the end of a fishing line (and thus get cast out along with the bait) is collectively called terminal tackles, which include hooks, leaders, floats, sinkers/feeders, swivels and any attached snaps and/or split rings. Sometimes the term " rig" is used for a routine assembly of terminal tackle combination. Fishing tackle can be contrasted with fishing techniques. Fishing tackle refers to the physical equipment that is used when fishing, whereas fishing techniques refers to the manner in which the tackle is used (or "presented") when ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Concrete
Concrete is a composite material composed of fine and coarse aggregate bonded together with a fluid cement (cement paste) that hardens (cures) over time. Concrete is the second-most-used substance in the world after water, and is the most widely used building material. Its usage worldwide, ton for ton, is twice that of steel, wood, plastics, and aluminum combined. Globally, the ready-mix concrete industry, the largest segment of the concrete market, is projected to exceed $600 billion in revenue by 2025. This widespread use results in a number of environmental impacts. Most notably, the production process for cement produces large volumes of greenhouse gas emissions, leading to net 8% of global emissions. Other environmental concerns include widespread illegal sand mining, impacts on the surrounding environment such as increased surface runoff or urban heat island effect, and potential public health implications from toxic ingredients. Significant research and development is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eclogite
Eclogite () is a metamorphic rock containing garnet (almandine-pyrope) hosted in a matrix of sodium-rich pyroxene (omphacite). Accessory minerals include kyanite, rutile, quartz, lawsonite, coesite, amphibole, phengite, paragonite, zoisite, dolomite, corundum and, rarely, diamond. The chemistry of primary and accessory minerals is used to classify three types of eclogite (A, B, and C). The broad range of eclogitic compositions has led a longstanding debate on the origin of eclogite xenoliths as subducted, altered oceanic crust. Origins Eclogites typically result from high to ultrahigh pressure metamorphism of mafic rock at low thermal gradients of < as it is subducted to the lower crust to depths in a subduction zone. Class ...
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Jan De Nul
Jan De Nul Group is a Belgian family-owned company, with the financial headquarters in Luxembourg, that provides services relating to the construction and maintenance of maritime infrastructure on an international basis. Its main focus is dredging (including other forms of marine engineering), which accounts for 85% of its turnover. Other areas include civil engineering and environmental technology. History Founded in 1938, in Hofstade near Aalst, Belgium, Jan De Nul started as a construction company specialised in civil works and maritime construction. It was only in 1951 that the company entered into the dredging business. Recently it has forayed into offshore wind business and have been successful in securing major European wind energy projects. At the end of 2012, Jan De Nul had 6000 employees and a yearly turnover of 2 billion euro. Other major dredging companies are Dutch companies Royal Boskalis Westminster and Van Oord, and the Belgian DEME. Jan De Nul was voted the mos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DEME
In Ancient Greece, a deme or ( grc, δῆμος, plural: demoi, δημοι) was a suburb or a subdivision of Athens and other city-states. Demes as simple subdivisions of land in the countryside seem to have existed in the 6th century BC and earlier, but did not acquire particular significance until the reforms of Cleisthenes in 508 BC. In those reforms, enrollment in the citizen-lists of a deme became the requirement for citizenship; prior to that time, citizenship had been based on membership in a phratry, or family group. At this same time, demes were established in the main city of Athens itself, where they had not previously existed; in all, at the end of Cleisthenes' reforms, Athens was divided into 139 demes, to which one can be added Berenikidai (established in 224/223 BC), Apollonieis (201/200 BC), and Antinoeis (added in 126/127). The establishment of demes as the fundamental units of the state weakened the ''gene'', or aristocratic family groups, that had dominated t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coastal Erosion
Coastal erosion is the loss or displacement of land, or the long-term removal of sediment and rocks along the coastline due to the action of waves, currents, tides, wind-driven water, waterborne ice, or other impacts of storms. The landward retreat of the shoreline can be measured and described over a temporal scale of tides, seasons, and other short-term cyclic processes. Coastal erosion may be caused by hydraulic action, abrasion, impact and corrosion by wind and water, and other forces, natural or unnatural. On non-rocky coasts, coastal erosion results in rock formations in areas where the coastline contains rock layers or fracture zones with varying resistance to erosion. Softer areas become eroded much faster than harder ones, which typically result in landforms such as tunnels, bridges, columns, and pillars. Over time the coast generally evens out. The softer areas fill up with sediment eroded from hard areas, and rock formations are eroded away. Also erosion commonly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bulk Carriers
A bulk carrier or bulker is a merchant ship specially designed to transport unpackaged bulk cargo — such as grains, coal, ore, steel coils, and cement — in its cargo holds. Since the first specialized bulk carrier was built in 1852, economic forces have led to continued development of these ships, resulting in increased size and sophistication. Today's bulk carriers are specially designed to maximize capacity, safety, efficiency, and durability. Today, bulk carriers make up 21 percent of the world's merchant fleets, and they range in size from single-hold mini-bulk carriers to mammoth ore ships able to carry 400,000 metric tons of deadweight (DWT). A number of specialized designs exist: some can unload their own cargo, some depend on port facilities for unloading, and some even package the cargo as it is loaded. Over half of all bulk carriers have Greek, Japanese, or Chinese owners, and more than a quarter are registered in Panama. South Korea is the largest single bu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ship Types
A ship is a large watercraft that travels the world's oceans and other sufficiently deep waterways, carrying cargo or passengers, or in support of specialized missions, such as defense, research, and fishing. Ships are generally distinguished from boats, based on size, shape, load capacity, and purpose. Ships have supported exploration, trade, warfare, migration, colonization, and science. After the 15th century, new crops that had come from and to the Americas via the European seafarers significantly contributed to world population growth. Ship transport is responsible for the largest portion of world commerce. The word ''ship'' has meant, depending on the era and the context, either just a large vessel or specifically a ship-rigged sailing ship with three or more masts, each of which is square-rigged. As of 2016, there were more than 49,000 merchant ships, totaling almost 1.8 billion dead weight tons. Of these 28% were oil tankers, 43% were bulk carriers, and 13% were con ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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