An integrated, net-negative system captures carbon and produces ethylene
Engineers at the University of Illinois Chicago have built a machine that captures carbon from flue gas and converts it to ethylene.
Dec 12, 2022
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141
Energy & Green Tech
Engineers at the University of Illinois Chicago have built a machine that captures carbon from flue gas and converts it to ethylene.
Dec 12, 2022
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141
Electronics & Semiconductors
A soft and flexible electronic "e-skin," so sensitive it can detect the minute temperature difference between an inhaled and an exhaled breath, could form the basis of a new form of on-skin biosensor. The ultrathin material ...
Nov 29, 2022
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85
Telecom
Researchers of Delft University of Technology, Vrije Universiteit Amsterdam and VSL have developed an alternative positioning system that is more robust and accurate than GPS, especially in urban settings. The working prototype ...
Nov 16, 2022
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199
Computer Sciences
A student in Carnegie Mellon University's School of Computer Science (SCS) has used reinforcement learning to help control nuclear fusion reactions, a significant step toward harnessing the immense power produced in nuclear ...
Sep 9, 2022
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341
Machine learning & AI
Color coding makes aerial maps much more easily understood. Through color, we can tell at a glance where there is a road, forest, desert, city, river or lake.
Aug 16, 2022
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109
Energy & Green Tech
Hydrogen production takes place using natural gas as the raw material, combined with a very special ceramic membrane. Both hydrogen production and CO2 capture are achieved in a single step, which makes the method highly energy ...
Jul 28, 2022
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185
Energy & Green Tech
For decades, scientists have been searching for a catalyst that dramatically reduces the cost of fabricating hydrogen fuel cells.
Jul 7, 2022
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11820
Machine learning & AI
National University of Singapore researchers have developed a machine-learning scheme that rapidly identifies previously unseen novel structures in disordered materials without human supervision. Their study was published ...
Jun 22, 2022
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75
Energy & Green Tech
An international team, which included Skoltech researchers and their colleagues from France, the United States, and Switzerland, found out why energy losses occur during the charge-discharge cycle in lithium-ion batteries ...
Jun 21, 2022
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172
Electronics & Semiconductors
The semiconductor industry has been growing steadily ever since its first steps in the mid-twentieth century and, thanks to the high-speed information and communication technologies it enabled, it has given way to the rapid ...
Jun 16, 2022
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42
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.
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