- multco CEN 530.09252 G4273h 2023
Her Space, Her Time
p055 ch. 3 . ESCAPE VELOCITY: PATHFINDERS IN SPACE EXPLORATION
- p068 "... in the 1960s. Tiny electronic components had to be precisely positioned on a silicon wafer and connected in a specific pattern without damaging the circuit. All that had to be done by hand while squinting through a microscope."
- WRONG. The planar components on the grid of die (chips) on the silicon wafer were built layer by layer with photolithography. UV light through a photomask prints every component in one "flash". Human microscope work WAS required to align the layers X/Y and rotation of each mask layer in the early 1960s, but that was mechanized. Properly calibrated processes and machines are far better than the human eye and hand.
- After the wafer was sawn into individual die (each with dozens to thousands to (in 2026) TRILLIONS of components), the die were positioned in a package, then wire bonded to the traces (like small circuit board runs) connected to the pins. In the 1960s, this was done by thousands of low-paid women. Today, entirely automated for almost all products.
p071 Turkish immigrant astrophysicist Dr. Dilhan Eryurt b 1926, PhD 1953, Canada 1959, NASA 1961 to 1973
p074 The Early Evolution of the Sun Dilhan Ezer
- Hayashi has predicted that the early contracting sun should be highly luminous and fully convective, if one makes a correct choice of the photospheric boundary condition in constructing solar models in the contracting stages. We have constructed a sequence of models which fully confirm his predictions. The maximum radius of the protosun consistent with gravitational stability is 57 Rsolar this has a luminosity of about 450 times that of the sun. As the protosun shrinks its stays fully convective until a radius of less than 3Rsolar is reached; the luminosity continues to decrease until a radius of 1.7Rsolar is reached. The sun requires about 2 million years to contract onto the main sequence, but this number is very uncertain because of the unsatisfactory state of convection theories. If the primitive solar material has the terrestrial ratio of deuterium to hydrogen, then a further 3 × 105 years is required to burn the deuterium. These numbers are very much less than previous studies had indicated. The degree of lithium burning in the outer convection zone of the sun is highly uncertain owing also to the unsatisfactory state of convection theories.