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Abnormal vibrations often occur in the liquid oxygen kerosene transmission pipelines of rocket engines, which seriously threaten their safety. Improper handling can result in failed rocket launches and significant economic losses. Therefore, this paper aims to examine vibrations in transmission pipelines.

In this study, a three-dimensional high-pressure pipeline model composed of corrugated pipes, multi-section bent pipes, and other auxiliary structures was established. The fluid–solid coupling method was used to analyse vibration characteristics of the pipeline under various external excitations. The simulation results were visualised using MATLAB, and their validity was verified via a thermal test.

In this study, the vibration mechanism of a complex high-pressure pipeline was examined via a visualisation method. The results showed that the low-frequency vibration of the pipe was caused by fluid self-excited pressure pulsation, whereas the vibration of the engine system caused a high-frequency vibration of the pipeline. The excitation of external pressure pulses did not significantly affect the vibrations of the pipelines. The visualisation results indicated that the severe vibration position of the pipeline thermal test is mainly concentrated between the inlet and outlet and between the two bellows.

The results of this study aid in understanding the causes of abnormal vibrations in rocket engine pipelines.

The causes of different vibration frequencies in the complex pipelines of rocket engines and the propagation characteristics of external vibration excitation were obtained.

In early 2014, recent Stanford University graduate Tyler Shultz was in a quandary. He had been working at Theranos, a blood-diagnostic company founded by Elizabeth Holmes, a Stanford-dropout wunderkind, for almost a year. Shultz had learned enough about the company to realize that its practices and the efficacy of its much-touted finger-prick blood-testing technology were questionable and that the company was going to great lengths to hide this fact from the public and from regulators.

Theranos and Holmes were Silicon Valley darlings, enjoying positive press and lavish attention from potential investors and technology titans alike. Just as companies like PayPal had revolutionized the stagnant payments industry and Uber had upended the for-hire transportation sector, Theranos had been positioned as the latest technology firm to substantially disrupt yet another mature sector: the medical laboratory business. By the start of 2014, the company had raised more than $400 million in funding, and had an estimated market valuation of $9 billion.

Shultz's situation was exacerbated by the fact that his grandfather, the highly respected former US Secretary of State George Shultz, was on the Theranos board and was one of Elizabeth Holmes's biggest supporters.

But Tyler Shultz worried about the customers he was convinced were receiving highly unreliable and often inaccurate blood-test results. With so much at stake, Shultz wondered how he should proceed. Should he raise his concerns with the firm's investors? Blow the whistle externally? Report to industry regulators? Go away quietly?

This case and its subsequent four brief follow-up cases are based largely on interviews with Tyler Shultz, and outline the dilemma he faced and the various steps he would take both to extricate himself from his unsavory position and let the public know the full extent of the deception at Theranos.

Five optional handouts are available to instructors to further discussion after the case has been debriefed. The handouts serve as additional decision points for the students if your class time permits.