Micronewton

Définitions de « micronewton »

Micronewton - Nom commun

• (Métrologie, Physique) Unité de mesure de force du Système international (SI), équivalent à un millionième de newton (10−6 newton), symbolisée par μN.

  Dans les laboratoires de pointe où la précision est cruciale, l'utilisation du micronewton permet une évaluation extrêmement fine des forces en jeu, ouvrant ainsi la voie à des avancées significatives dans des domaines aussi variés que la microélectronique et la biotechnologie.

Étymologie de « micronewton »

Citations contenant le mot « micronewton »

• However, controlling the test masses alone is not sufficient. LPF relies on “drag free” control of the spacecraft to keep it out of the way of the test masses. By reading out the position of the spacecraft relative to one of the test masses, the spacecraft’s attitude (its orientation relative to the reference frame defined by the test masses) is adjusted using thrusters capable of producing micronewton forces to precisely maintain the attitude relative to the test masses.

• "Here's another way of thinking about it: when the thrusters fire at full throttle, they produce a maximum force of 30 micronewtons -- equivalent to the weight of a mosquito landing on the spacecraft," said John Ziemer of JPL, ST7-DRS systems lead. "To maintain our precise position, the thrusters can be controlled in 0.1 micronewton increments, equivalent to the weight of that mosquito's antenna."

• The spacecraft serves as a shield to protect the test masses from external forces. When LISA Pathfinder responds to pressure from sunlight and microscopic dust impacts, the spacecraft automatically compensates by firing tiny bursts from its micronewton thrusters to prevent the test masses from being disturbed.

• The scientists found they had to apply a force of about 1 micronewton to remove a single Caulobacter crescentus from a glass pipette. Because C. crescentus is so small, the pulling force of 1 micronewton generates a huge stress of 70 newtons per square millimeter. That stress, which the bacterial adhesions could sometimes withstand, is equivalent to five tons per square inch -- three or four cars balanced atop a quarter. By contrast, commercial "super" glue breaks when a shear force of 18 to 28 newtons per square millimeter is applied.

• The system uses colloid micronewton thrusters, which operate by applying an electric charge to small droplets of liquid and accelerating them through an electric field, to precisely control the position of the spacecraft. Thrusters that work this way had never been successfully operated in space before LISA Pathfinder launched.

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