Chаpter 28 - A respirаtоry therаpist is reviewing data in the electrоnic health recоrd of an 8-year-old child with penetrating chest trauma who is intubated and receiving PC-CMV. The oxygen index (IO) is 22. Which of the following should the respiratory therapist conclude?
Wаtch the Timer!! Yоu hаve а tоtal оf 120 minutes to answer the questions and submit your response. Leave yourself plenty of time to scan and upload your responses to Brightspace before the timer runs out. Reminder: This exam is to be completed individually. You must not discuss the quiz content with classmates. Answer the questions below on paper. Scan and submit your paper to Brightspace. Honorlock must remain running until you have finished submitting your work to Brightspace. 1. [25 pts] A New Horizons-type mission to Pluto is being planned with a useful scientific payload of 100 kg. You are the propulsion system designer and have three various electric propulsion thruster technologies to choose from (see table below). Consider a power-system specific mass (alpha ) = 10-2 kg/W and a required mission (Delta V)= 10 km/s. Thruster option Specific impulse, ({I_{sp}}) Thrust Efficiency of power conversion into thrust, (eta ) HET 2000 s 100 mN 0.5 GIT 6000 s 100 mN 0.5 MPDT 5000 s 1000 mN 0.5 Determine the exhaust velocity and mass flow rate for each thruster. Determine the total mass of the propulsion system and the individual components (propellant mass ({m_{pr}}) and power processing unit mass ({m_{PPU}})) for each thruster. Assume that the mass of the thruster assembly is negligible. Determine the useful payload fraction (frac{{{m_u}}}{{{m_0}}}) for each thruster. Determine the required input power for each thruster and the corresponding mission duration. Using relevant material provided in the lecture notes, estimate what optimal ({I_{sp}}) you would recommend for each thruster in this mission in order to minimize the total propulsion system mass. Compare and discuss the total propulsion system mass and mission duration for each thruster option. 2. [25 pts] For an H2-based electrothermal accelerator, do the following: Write out the equation of state (frac{P}{rho }) in terms coefficients ({alpha _2},;{alpha _1},;alpha _2^ + ,alpha _1^ + ,;)and ({alpha _e};), and identify the particle species corresponding to each (alpha ). During a thruster test at a chamber pressure of 10-2 atm, the coefficient ({alpha _2}) was measured at ({alpha _2})= 0.8. Determine the corresponding ({alpha _p}) and chamber temperature ({T_c}). Using the relevant material provided in the lecture notes, estimate the corresponding specific impulse (({I_{sp}})) assuming no frozen flow losses ((xi = 0)). Then repeat the calculation for the fully frozen flow case ((xi = 1)). Estimate ({eta _f}). You are the propulsion system engineer and are required to design a thruster that generates 300 mN of thrust. Assuming that the only loss mechanism in the thruster is due to frozen flow, estimate the required hydrogen mass flow rate and electric power for (xi = 0) and for (xi = 1) (neglect the “cold-flow power”). 3. [25 pts] Use the ionization degree plot (calculated from the Saha equation) illustrated in Slide 45 (Section 3: Plasma Fundamentals) to evaluate parameters of argon in thermal equilibrium at 1 atm. Assuming an ionization degree (alpha = frac{{{n_e}}}{{{n_g}}} = 0.1), determine the corresponding neutral, ion, and electron temperatures; electron and gas number densities; cross-section for elastic electron-gas collisions (use the argon data provided on Slide 37, indicated as “A” on the plot); cross-section for elastic electron-ion collisions (use a Coulomb logarithm ({rm{ln}}left( {rm{Lambda }} right))=5); and the mean-free path for elastic electron-gas and electron-ion collisions. 4. [25 pts] Consider an idealized coaxial magnetoplasmadynamic (MPD) thruster of length (L), consisting of a central cylindrical rod electrode of radius (a) and a concentric outer cylindrical electrode of radius (b) (where (b) > (a)). The two electrodes share the same longitudinal axis and extend over the full length (L). The thruster is driven by a power source that maintains a voltage (V) between the electrodes. Treat (V), (a), (b), and (L) as given. Determine distribution of the electric field within the thruster. Congratulations! You are almost done with this exam. DO NOT end the Honorlock session until you have submitted your work to Brightspace. Submission Instructions Use your phone to scan your answer sheet and save it as a PDF. Make sure your scan is legible! Email the PDF to yourself or save it to the cloud (Google Drive, etc.). Click Add File at the bottom of the page. Locate and upload your exam PDF. Click the Submit Quiz to end the exam and end the Honorlock session.