Questo articolo è dedicato principalmente a coloro che furono selezionati come astronauti dai programmi spaziali degli Stati Uniti e dell’Unione
Sovietica ma perirono prima di andare nello spazio. Sono i protagonisti
dimenticati, le vittime che pagarono il prezzo più alto per raggiungere
la nuova frontiera. Di uno di loro si è saputo soltanto anni dopo,
quando i segreti del programma spaziale sovietico vennero a galla.
Ex astris, scientia.
New 3-D Printer Uses Light to Build Objects in Minutes
The next generation of desktop 3-D printers might do away with the excruciatingly slow process that current units use. Researchers have unveiled a printer that replaces the current extruder nozzle that squeezes out melted plastic one layer at a time with light and oxygen.
The makers of the Carbon3D printer have demonstrated a technique they call continuous liquid interface production (CLIP), which grows 3-D printed parts out of a liquid resin bath. Ultraviolet light and oxygen work to build a stronger part in layers just tens of microns wide. Build times can be reduced from hours to minutes, they say.
Their work builds on the process called stereolithography, an additive manufacturing technique developed in the 1980s that builds parts layer by layer with liquid resin cured by light.
“By rethinking the whole approach to 3-D printing, and the chemistry and physics behind the process, we have developed a new technology that can create parts radically faster than traditional technologies by essentially ‘growing’ them in a pool of liquid,” said University of North Carolina, Chapel Hill chemistry professor Joseph DeSimone, who coinvented the technique and is also Carbon3D’s CEO. See more images and learn more below.
Una stima di massima dei salari di alcuni dei professionisti più noti
‘For Allah’ Inscription Found on Viking Era Ring
Ancient tales about Viking expeditions to Islamic countries had some elements of truth, according to recent analysis of a ring recovered from a 9th century Swedish grave.
Featuring a pink-violet colored stone with an inscription that reads “for Allah” or “to Allah,” the silver ring was found during the 1872-1895 excavations of grave fields at the Viking age trading center of Birka, some 15.5 miles west of Stockholm.
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