The findings have been published but not peer-reviewed, which reads: "One quarter of the northern hemisphere is underlain by permanently frozen ground, referred to as permafrost. Hey JV (2014) Design, implementation, and characterization of a novel lidar ceilometer. Springer Cham, London. https://doi.org/10.1007/978-3-319-12613-5 Parry LA, Ashcroft IA, Wildman RD (2019) Geometrical effects on residual stress in selective laser melting. Addit Manuf 25:166–175. https://doi.org/10.1016/j.addma.2018.09.026 https://www.elementum3d.com/wp-content/uploads/2021/12/An-inside-look-at-how-AM-commercial-aluminum-alloys-are-made-possible-using-RAM-technology.pdf

The inner powders removal was carefully controlled and a T6 thermal cycle was provided in a Nabertherm LH120/14 controlled atmosphere hoven. The heat inducing laser fusion process results in a significant residual stress and, therefore, in an unstable mirror [ 36, 37]. A stress relieving heat treatment was applied according to the following characteristics: the mirror was slowly heated at 5 °C/min rate up to the soaking temperature of 550 °C and maintained for 1.5 h; after a water quenching, an aging at 165 °C for 24 h was provided. The question - which has since been shared on social media - starts off like this: "Albert and Bernard just became friends with Cheryl, and they want to know when her birthday is. Cheryl gives them a list of 10 possible dates. Cheryl then tells Albert and Bernard separately the month and the day of her birthday respectively." Speculum metal might look light and fluid when it’s molten, but it’s actually very heavy: our resulting mirror disc – a modest 6 inches in diameter – weighed about 4kg! Still, that’s peanuts compared to the 6-foot speculum metal mirror from the Great Rosse Telescope in our collection, which weighs in at over 4 tonnes… Casting the molten speculum metal into its mould at Coles Castings Foundry, Dorset. Credit: Matthew Howles.ISO/ASTM52900:2021 (2021) Additive manufacturing - general principles — fundamentals and vocabulary. ASTM International Albert says: "I don't know when Cheryl's birthday is, but I know that Bernard does not know too," and Bernard states: "At first I don't know when Cheryl’s birthday is, but I know now." This then prompts Albert to say: "Then I also know when Cheryl's birthday is."

There has been some discussion about whether infection changes human behaviour or not, possibly making some infected humans more likely to take risks, but it's certainly not a dramatic behavioural change like we see with zombies. Kovalev VA, Eichinger WE (2004) Elastic Lidar: theory, practice, and analysis methods. Wiley-Interscience We had a go at making speculum metal telescope mirrors – arsenic NOT included – as part of a “how-it’s-made” film for the Science City gallery. We wanted to showcase some of the extraordinary craft skills needed to produce many of the historical scientific instruments in our collection. The dynamic analysis showed smaller displacements than the case the mirror is assembled via tightening the screws; A static balancing of this lightened mirror was provided. In particular, the original mass of 205 g was reduced to 154 g. Therefore, the mirror total mass was cut by 25% (from 415 to 311.8 g).Bottini L (2021) Study of selective laser melting process parameters to improve the obtainable roughness of AlSi10Mg parts. Selected Topics in Manufacturing. pp 121–139. Springer, Cham. https://doi.org/10.1007/978-3-030-57729-2_9 To celebrate International Astronomy Day, Assistant Curator Matthew Howles takes an in-depth look at the most iconic of astronomical instruments: the telescope. Artists Necole Schmitz, Stephen Coles and Katie Surridge took on the casting processes, melting the specially alloyed speculum metal in a chimney furnace at over 1000 degrees Celsius before pouring it into disc-shaped moulds. They said: "From the first statement, we know that Albert is sure that Bernard doesn't know the birthday, so May and June should be ruled out (day 19 only appears in May and day 18 only appears in June). In other words, if Albert had May or June, then he cannot be sure that Bernard doesn’t know, since Bernard could have had 18 or 19. The choice was made to use a star trabecular structure which allows excellent quality in the fabrication of the beams, when properly inclined, using SLM technology.

Scientists agree that the beads are well-intentioned, but worry about their potential effects on the Arctic ecosystem. If they float around there indefinitely, “it’s just going to clog up the ocean and mess with the ecosystem,” says Cecilia Bitz, an atmospheric scientist at the University of Washington who specialises in Arctic sea ice. Nuechterlein J, Iten J (2016) Reactive additive manufacturing. Patent Application Publication No. US2016/0271878A1 Sep.22,2016https://www.elementum3d.com/wp-content/uploads/2021/11/A2024-RAM10-Data-Sheets-2021-04-02-FINAL.pdf A tweet with almost 7,000 likes said: "How is a zombie virus get buried in a frozen lake? And why did they dig it up? That doesn't even make sense". The interferometric measurement pointed out that the fabricated mirror must be finished and measured in the same way as the final assembled configuration; otherwise, it exceeds the required limits, as evidenced in the free arrangement.

The motivation of the use of the AM technology is the introduction of internal lattice structures, aiming to reduce the component weight without compromising the performance. To furtherly improve the mechanical properties, an AA2024 MMC is used.Inside permafrosts are masses of biodiversity which humanity still has much to learn about including microbes known as extremophiles.