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[1] A simple, so-called "lateral" harmonograph uses two pendulums to control the movement of a pen relative to a drawing surface. One pendulum moves the pen back and forth along one axis, and the other pendulum moves the drawing surface back and forth along a perpendicular axis.
2,6-di-tert-butylphenol is a precursor to more complex compounds used as antioxidants and light-protection agents for the stabilization for polymers. Of particular note is methyl-3-(3,5-di- tert -butyl-4-hydroxyphenyl)-propionate (CAS# 6386-38-5), which is formed by the Michael addition of methyl acrylate .
By 1900, two primary types of mimeographs had come into use: a single-drum machine and a dual-drum machine. The single-drum machine used a single drum for ink transfer to the stencil, and the dual-drum machine used two drums and silk-screens to transfer the ink to the stencils. The single drum (example Roneo) machine could be easily used for ...
In organic chemistry, phenols, sometimes called phenolics, are a class of chemical compounds consisting of one or more hydroxyl groups (−O H) bonded directly to an aromatic hydrocarbon group. [1] The simplest is phenol, C 6 H 5 OH. Phenolic compounds are classified as simple phenols or polyphenols based on the number of phenol units in the ...
The Great Phenol Plot was a clandestine effort by the German government during the early years of World War I to divert American-produced phenol from the manufacture of high explosives that supported the British war effort. It was used by the German-owned Bayer company, which could no longer import phenol from Britain, to produce aspirin.
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A second pair of parallelogram links maintains vertical correspondence between the two pens ("D" and "E" on diagram). These consist of two variable parallelogram frames attached at a common edge, one of which is also attached to the bridge, while the other is attached to one of the pen supports at each corner.
1525: Albrecht Dürer, in his illustration Man drawing a lute, shows an artist using a perspective machine to create a drawing. The machine consists of a wooden frame with a taut string passing through it to represent the viewer's line of sight. [4] Dürer built his second model of such a machine in the same year. [5]