DR Congo govt gives go-ahead to restarting nuclear reactor
The Democratic Republic of Congo has authorised the startup of an experimental nuclear reactor that has been mothballed for more than a quarter of a century.
Feb 21, 2020
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The Democratic Republic of Congo has authorised the startup of an experimental nuclear reactor that has been mothballed for more than a quarter of a century.
Feb 21, 2020
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Engineering
One of the many ways to reduce the energy required for transportation is to make vehicles lighter. High-strength (HS) steel is perfect candidate materials for this purpose, as its higher weight-to-strength ratio allows for ...
Mar 29, 2023
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Energy & Green Tech
As the costs of importing energy soars worldwide and climate crises wreak havoc, interest in nuclear power is on the rise with nations scrambling to find alternative sources.
Aug 27, 2022
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Engineering
Cement materials, including cement paste, mortar, and concrete, are the most widely manufactured materials in the world. Their carbon footprint is similarly hefty: The processes involved in making cement contribute almost ...
Oct 2, 2017
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Engineering
In circuitry, etching is used to remove the deformed layer created during the grinding and polishing of metal components by selective chemical reactions. Now, a research group at Nagoya University in Japan has developed a ...
Feb 22, 2023
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Energy & Green Tech
For centuries, the world was lit, in the words of a best-selling book, only by fire. Will the not-too-distant future see a world powered largely by fusion?
Nov 9, 2022
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Energy & Green Tech
Many of us are all too familiar with how strain in work relationships can impact performance, but new research shows that materials in electricity-producing fuel cells may be sensitive to strain on an entirely different level.
Sep 9, 2022
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Energy & Green Tech
Perovskite is a promising material. It captures the sun's rays and efficiently converts them into solar energy. It is also much cheaper than the current generation of silicon solar cells. But why are the Dutch rooftops not ...
Oct 14, 2021
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Engineering
A team lead by Professor Simon Brown at the University of Canterbury (UC) has developed computer chips with brain-like functionality, that could significantly reduce global carbon emissions from computing.
Nov 6, 2019
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Energy & Green Tech
The United Arab Emirates announced Tuesday that its Barakah nuclear power plant has started commercial operations, in a first for the Arab world.
Apr 6, 2021
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The atom is a basic unit of matter consisting of a dense, central nucleus surrounded by a cloud of negatively charged electrons. The atomic nucleus contains a mix of positively charged protons and electrically neutral neutrons (except in the case of hydrogen-1, which is the only stable nuclide with no neutron). The electrons of an atom are bound to the nucleus by the electromagnetic force. Likewise, a group of atoms can remain bound to each other, forming a molecule. An atom containing an equal number of protons and electrons is electrically neutral, otherwise it has a positive or negative charge and is an ion. An atom is classified according to the number of protons and neutrons in its nucleus: the number of protons determines the chemical element, and the number of neutrons determine the isotope of the element.
The name atom comes from the Greek ἄτομος/átomos, α-τεμνω, which means uncuttable, something that cannot be divided further. The concept of an atom as an indivisible component of matter was first proposed by early Indian and Greek philosophers. In the 17th and 18th centuries, chemists provided a physical basis for this idea by showing that certain substances could not be further broken down by chemical methods. During the late 19th and early 20th centuries, physicists discovered subatomic components and structure inside the atom, thereby demonstrating that the 'atom' was divisible. The principles of quantum mechanics were used to successfully model the atom.
Relative to everyday experience, atoms are minuscule objects with proportionately tiny masses. Atoms can only be observed individually using special instruments such as the scanning tunneling microscope. Over 99.9% of an atom's mass is concentrated in the nucleus, with protons and neutrons having roughly equal mass. Each element has at least one isotope with unstable nuclei that can undergo radioactive decay. This can result in a transmutation that changes the number of protons or neutrons in a nucleus. Electrons that are bound to atoms possess a set of stable energy levels, or orbitals, and can undergo transitions between them by absorbing or emitting photons that match the energy differences between the levels. The electrons determine the chemical properties of an element, and strongly influence an atom's magnetic properties.
This text uses material from Wikipedia, licensed under CC BY-SA