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Topic Review
Osmium-165
Osmium (76Os) has seven naturally occurring isotopes, five of which are stable: 187Os, 188Os, 189Os, 190Os, and (most abundant) 192Os. The other natural isotopes, 184Os, and 186Os, have extremely long half-life (1.12×1013 years and 2×1015 years, respectively) and for practical purposes can be considered to be stable as well. 187Os is the daughter of 187Re (half-life 4.56×1010 years) and is most often measured in an 187Os/188Os ratio. This ratio, as well as the 187Re/188Os ratio, have been used extensively in dating terrestrial as well as meteoric rocks. It has also been used to measure the intensity of continental weathering over geologic time and to fix minimum ages for stabilization of the mantle roots of continental cratons. However, the most notable application of Os in dating has been in conjunction with iridium, to analyze the layer of shocked quartz along the Cretaceous–Paleogene boundary that marks the extinction of the dinosaurs 66 million years ago. There are also 30 artificial radioisotopes, the longest-lived of which is 194Os with a half-life of six years; all others have half-lives under 94 days. There are also nine known nuclear isomers, the longest-lived of which is 191mOs with a half-life of 13.10 hours. All isotopes and nuclear isomers of osmium are either radioactive or observationally stable, meaning that they are predicted to be radioactive but no actual decay has been observed.
  • 282
  • 03 Nov 2022
Topic Review
Circinus
Circinus is a small, faint constellation located in the southern sky. Named after the Latin word for compass, it was first introduced in the 18th century by the French astronomer Nicolas Louis de Lacaille during his observations of the southern hemisphere. Despite its modest size, Circinus harbors several intriguing celestial objects, including a notable planetary nebula and multiple star systems of scientific interest.
  • 280
  • 08 Mar 2024
Topic Review
Osmium-189
Osmium (76Os) has seven naturally occurring isotopes, five of which are stable: 187Os, 188Os, 189Os, 190Os, and (most abundant) 192Os. The other natural isotopes, 184Os, and 186Os, have extremely long half-life (1.12×1013 years and 2×1015 years, respectively) and for practical purposes can be considered to be stable as well. 187Os is the daughter of 187Re (half-life 4.56×1010 years) and is most often measured in an 187Os/188Os ratio. This ratio, as well as the 187Re/188Os ratio, have been used extensively in dating terrestrial as well as meteoric rocks. It has also been used to measure the intensity of continental weathering over geologic time and to fix minimum ages for stabilization of the mantle roots of continental cratons. However, the most notable application of Os in dating has been in conjunction with iridium, to analyze the layer of shocked quartz along the Cretaceous–Paleogene boundary that marks the extinction of the dinosaurs 66 million years ago. There are also 30 artificial radioisotopes, the longest-lived of which is 194Os with a half-life of six years; all others have half-lives under 94 days. There are also nine known nuclear isomers, the longest-lived of which is 191mOs with a half-life of 13.10 hours. All isotopes and nuclear isomers of osmium are either radioactive or observationally stable, meaning that they are predicted to be radioactive but no actual decay has been observed.
  • 279
  • 14 Oct 2022
Topic Review
Nemesis
Nemesis is a hypothesized companion object orbiting the Sun, motivated by the claim of a terrestrial extinction periodicity. Astronomer Percival Lowell in 1915 thought that some glitches in the orbit of Uranus might be caused by what he dubbed Planet X, and led to the discovery of Pluto in 1930. The existence of the object beyond Pluto may be able to explain the architecture of the Edgeworth–Kuiper Belt and a secular perihelion precession of Saturn. The Nemesis hypothesis has also been used to explain the measurements of the ages of 155 lunar spherules from the Apollo 14 site.
  • 278
  • 14 Jan 2024
Topic Review
Plasma-Driven Phenomena
Plasma-driven science is defined as the artificial control of physical plasma-driven phenomena based on complex interactions between nonequilibrium open systems.
  • 278
  • 18 Mar 2024
Topic Review
Micro-Imaging Dust Analysis System
The Micro-Imaging Dust Analysis System (MIDAS) is one of several instruments on the European Space Agency's Rosetta mission which studied in-situ the environment around the active comet 67P/Churyumov–Gerasimenko as it flew into the inner Solar System. MIDAS is an atomic force microscope (AFM) designed to collect dust particles emitted from the comet, and then scan them with a very sharp needle-like tip to determine their 3D structure, size and texture with very high resolution (4 nanometers).
  • 277
  • 20 Oct 2022
Topic Review
MicrOmega-IR
MicrOmega-IR is an infrared hyperspectral microscope that is part of the science payload on board the European Rosalind Franklin rover, tasked to search for biosignatures on Mars. The rover is planned to land on Mars in the mid- or late 2020s. MicrOmega-IR will analyse in situ the powder material derived from crushed samples collected by the rover's core drill.
  • 277
  • 30 Oct 2022
Topic Review
Emergent Dimensionality
The principle of emergent dimensionality states that 3-dimensional reality does not exist observer-independently but emerges, for a living agent, from an omnidimensional graph of nature that contains all unobservable extra dimensions.
  • 276
  • 16 Aug 2024
Topic Review
Copper RTD directly fabricated on ceramic-coated stainless-steel tube
Reducing the economic and environmental impact of industrial process may be achieved by the smartisation of different components. In this work, tube smartisation is presented via direct fabrication of a copper (Cu)-based resistive temperature detector (RTD) on their outer surfaces. The testing was carried out between room temperature and 250 °C. For this purpose, copper depositions were studied using mid-frequency (MF) and high-power impulse magnetron sputtering (HiPIMS). Stainless steel tubes with an outside inert ceramic coating were used after giving them a shot blasting treatment. The Cu deposition was performed at around 425 °C to improve adhesion as well as the electrical properties of the sensor. To generate the pattern of the Cu RTD, a photolithography process was carried out. The RTD was then protected from external degradation by a silicon oxide film deposited over it by means of two different techniques: sol–gel dipping technique and reactive magnetron sputtering.
  • 275
  • 25 Jun 2023
Topic Review
Per- and Polyfluoroalkyl Substances (PFAS) Sorption
Per- and polyfluorinated alkyl substances (PFAS) are an environmentally persistent group of chemicals that can pose an imminent threat to human health through groundwater and surface water contamination. The primary adsorption mechanisms identified in the literature are electrostatic interactions and hydrophobic interactions.
  • 273
  • 18 Jul 2023
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