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Ferrocement or ferro-cement [1] is a system of construction using reinforced mortar [2] or plaster (lime or cement, sand, and water) applied over an "armature" of metal mesh, woven, expanded metal, or metal-fibers, and closely spaced thin steel rods such as rebar. The metal commonly used is iron or some type of steel, and the mesh is made with ...
A modern ferrocerium firesteel product is composed of an alloy of rare-earth metals called mischmetal, containing approximately 20.8% iron, 41.8% cerium, about 4.4% each of praseodymium, neodymium, and magnesium, plus 24.2% lanthanum. [5] A variety of other components are added to modify the spark and processing characteristics. [2]
The advantage of ferrocement construction is that materials are cheap and readily available, while the disadvantages are that construction labor costs are high, as are operating costs. (Ferrocement ships require thick hulls, which results in either a larger cross-sectional area that hurts hydrodynamics, or leaves less space for cargo.)
In the heart of Asia, deep underground, two huge tectonic plates are crashing into each other — a violent but slow-motion bout of geological bumper cars that over time has sculpted the soaring ...
Archimedes is said to have remarked about the lever: "Give me a place to stand on, and I will move the Earth." The recorded history of structural engineering starts with the ancient Egyptians. In the 27th century BC, Imhotep was the first structural engineer known by name and constructed the first known step pyramid in Egypt.
The iron cycle is an important component of the terrestrial ecosystems. The ferrous form of iron, Fe 2+, is dominant in the Earth's mantle, core, or deep crust. The ferric form, Fe 3+, is more stable in the presence of oxygen gas. [22] Dust is a key component in the Earth's iron cycle.
An axe made of iron, dating from the Swedish Iron Age The earliest iron objects found in Europe date from the 3rd millennium BC, and are assigned to the Yamnaya culture and Catacomb culture . [ 49 ] [ 50 ] Eastern Europe, especially the Cis-Ural region, shows the highest concentration of early and middle Bronze Age iron objects in western ...
To the peasant farmers, the campesinos, the cause of the contamination is evident. The hills contain flecks of gold ore, one of the rarest minerals on Earth. And for 22 years, the American company Newmont Mining Corp., with financing from the business-lending arm of the World Bank, has blasted apart hills and used toxic chemicals to get it out.