Energy & Green Tech
Arid and surrounded by the salt waters of the Persian Gulf, World Cup host Qatar is among the world's most water-stressed countries. The nation of 2.9 million people has no rivers, and receives less than four inches (10 centimeters) ...
Nov 10, 2022
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Engineering
The plaster and mortar used in facades often contain heavy metals and biocides that leach out and infiltrate into the soil when it rains. The Fraunhofer Institute for Building Physics IBP has created a model that combines ...
Oct 4, 2023
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A heavy metal is a member of an ill-defined subset of elements that exhibit metallic properties, which would mainly include the transition metals, some metalloids, lanthanides, and actinides. Many different definitions have been proposed—some based on density, some on atomic number or atomic weight, and some on chemical properties or toxicity. The term heavy metal has been called "meaningless and misleading" in an IUPAC technical report due to the contradictory definitions and its lack of a "coherent scientific basis". There is an alternative term toxic metal, for which no consensus of exact definition exists either. As discussed below, depending on context, heavy metal can include elements lighter than carbon and can exclude some of the heaviest metals. Heavy metals occur naturally in the ecosystem with large variations in concentration. Nowadays anthropogenic sources of heavy metals, i.e. pollution, have been introduced to the ecosystem. Waste derived fuels are especially prone to contain heavy metals so they should be a central concern in a consideration of their use.
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