Users manual for program SSFREQ intermediate mode stability curves: Developed for use on a PC computer

The piping in a liquid rocket can assume complex configurations due to multiple tanks, multiple engines, and structures that must be piped around. The capability to handle some of these complex configurations have been incorporated into the SSFREQ code. The capability to modify the input on line has been implemented. The configurations allowed include multiple tanks, multiple engines, the splitting of a pipe into equal segments going to different (or the same) engines. This program will handle the following type elements: straight pipes, bends, inline accumulators, tuned stub accumulators, Helmholtz resonators, parallel resonators, pumps, split pipes, multiple tanks, and multiple engines

Users manual for program ADMIT: Admittance and pressure transfer function developed for use on a PC computer

The piping in a liquid rocket can assume complex configurations due to multiple tanks, multiple engines, and structures that must be piped around. The capability to handle some of these complex configurations have been incorporated into the ADMIT code. The capability to modify the input on line has been implemented. The configurations allowed include multiple tanks, multiple engines, the splitting of a pipe into unequal segments going to different (or the same) engines. This program will handle the following type elements: straight pipes, bends, inline accumulators, tuned stub accumulators, Helmholtz resonators, parallel resonators, pumps, split pipes, multiple tanks, and multiple engines

Users manual for program NYQUIST: Liquid rocket nyquist plots developed for use on a PC computer

The piping in a liquid rocket can assume complex configurations due to multiple tanks, multiple engines, and structures that must be piped around. The capability to handle some of these complex configurations have been incorporated into the NYQUIST code. The capability to modify the input on line has been implemented. The configurations allowed include multiple tanks, multiple engines, and the splitting of a pipe into unequal segments going to different (or the same) engines. This program will handle the following type elements: straight pipes, bends, inline accumulators, tuned stub accumulators, Helmholtz resonators, parallel resonators, pumps, split pipes, multiple tanks, and multiple engines. The code is too large to compile as one program using Microsoft FORTRAN 5; therefore, the code was broken into two segments: NYQUIST1.FOR and NYQUIST2.FOR. These are compiled separately and then linked together. The final run code is not too large (approximately equals 344,000 bytes)

Propulsion stability codes for liquid propellant propulsion systems developed for use on a PC computer

Research into component modeling and system synthesis leading to the analysis of the major types of propulsion system instabilities and the characterization of various components characteristics are presented. Last year, several programs designed to run on a PC were developed for Marshall Space Flight Center. These codes covered the low, intermediate, and high frequency modes of oscillation of a liquid rocket propulsion system. No graphics were built into these programs and only simple piping layouts were supported. This year's effort was to add run time graphics to the low and intermediate frequency codes, allow new types of piping elements (accumulators, pumps, and split pipes) in the low frequency code, and develop a new code for the PC to generate Nyquist plots

Stability codes for a liquid rocket implemented for use on a PC

The high frequency code has been made an interactive code using FORTRAN 5.0. The option to plot n-tau curves was added using the graphics routines of FORTRAN 5.0 and GRAFMATIC. The user is now able to run with input values non-dimensional (as in the original code) or dimensional. Input data may be modified from the keyboard. The low and intermediate frequency codes have been run through a set of variations. This will help the user to understand how the stability of a configuration will change if any of the input data changes

Network effects in two-sided markets: why a 50/50 user split is not necessarily revenue optimal

Our study applies empirical scrutiny to the network effects of a leading European online dating platform. While one might expect equal gender representation on such a platform to yield the best user experience and the highest revenue per user, our analysis shows that the platform requires only 36.2 % of its user base to be female to maximize revenue, primarily because women exert stronger positive cross-side network effects on men than vice versa; this optimum results in 17.2 % higher sales than a 50/50 split. Intermediaries of two-sided markets can use our model to improve user acquisition strategies