Problem
Analysis
To be fair to long time puzzle followers, sTEm-at-Work Puzzle 36does violate the rules for sTEm-at-work puzzles. The solution to the puzzle is supposed to be provided in the combined information presented in the puzzle text and the puzzle plot(s). For puzzle 36, the reader needed to also know that when pressure is applied to a fluid the fluid demonstrates a capacitive like effect. The magnitude of that “RC” effect depends on the properties of the fluid, and when necessary, can be reduced but not eliminated. This valve does leak, but the “RC” rounding of the edges of the square wave shape is not because the valve leaks. The rounding is because of the capacitive effect of the hydraulic fluid. This is the reason for the suggestion in last month’s answer text that sTEm-at-Work puzzle 36represents a great segway for lessons on related RC time constant concepts including the material properties and mathematics that generate and predict an RC response, respectively. Since a material’s “RC” type response to an applied forcing function like pressure, or voltage is so common, taking the time to have students explore the concept in as much detail as can be assimilated is good use of instructional time.
Solution
The Tech rejected the actuator because the test results shown below were not the same shape as the applied pressure test pattern shown above. NO
FLATE Impact on Pages 16-17