Large liquid rocket engine transient performance simulation system

A simulation system, ROCETS, was designed and developed to allow cost-effective computer predictions of liquid rocket engine transient performance. The system allows a user to generate a simulation of any rocket engine configuration using component modules stored in a library through high-level input commands. The system library currently contains 24 component modules, 57 sub-modules and maps, and 33 system routines and utilities. FORTRAN models from other sources can be operated in the system upon inclusion of interface information on comment cards. Operation of the simulation is simplified for the user by run, execution, and output processors. The simulation system makes available steady-state trim balance, transient operation, and linear partial generation. The system utilizes a modern equation solver for efficient operation of the simulations. Transient integration methods include integral and differential forms for the trapezoidal, first order Gear, and second order Gear corrector equations. A detailed technology test bed engine (TTBE) model was generated to be used as the acceptance test of the simulation system. The general level of model detail was that reflected in the Space Shuttle Main Engine DTM. The model successfully obtained steady-state balance in main stage operation and simulated throttle transients, including engine starts and shutdown. A NASA FORTRAN control model was obtained, ROCETS interface installed in comment cards, and operated with the TTBE model in closed-loop transient mode

Large liquid rocket engine transient performance simulation system

Phase 1 of the Rocket Engine Transient Simulation (ROCETS) program consists of seven technical tasks: architecture; system requirements; component and submodel requirements; submodel implementation; component implementation; submodel testing and verification; and subsystem testing and verification. These tasks were completed. Phase 2 of ROCETS consists of two technical tasks: Technology Test Bed Engine (TTBE) model data generation; and system testing verification. During this period specific coding of the system processors was begun and the engineering representations of Phase 1 were expanded to produce a simple model of the TTBE. As the code was completed, some minor modifications to the system architecture centering on the global variable common, GLOBVAR, were necessary to increase processor efficiency. The engineering modules completed during Phase 2 are listed: INJTOO - main injector; MCHBOO - main chamber; NOZLOO - nozzle thrust calculations; PBRNOO - preburner; PIPE02 - compressible flow without inertia; PUMPOO - polytropic pump; ROTROO - rotor torque balance/speed derivative; and TURBOO - turbine. Detailed documentation of these modules is in the Appendix. In addition to the engineering modules, several submodules were also completed. These submodules include combustion properties, component performance characteristics (maps), and specific utilities. Specific coding was begun on the system configuration processor. All functions necessary for multiple module operation were completed but the SOLVER implementation is still under development. This system, the Verification Checkout Facility (VCF) allows interactive comparison of module results to store data as well as provides an intermediate checkout of the processor code. After validation using the VCF, the engineering modules and submodules were used to build a simple TTBE

My Twilight Queen

https://digitalcommons.library.umaine.edu/mmb-vp/3490/thumbnail.jp

Behavior Patterns of the Adult Alfalfa Weevil in Cache Valley, Utah

The alfalfa weevil, Hypera postica (Gyllenhal), was first found in the United States in Salt Lake City, Utah, during 1904 (Titus, 1910b). It spread form this point of original introduction and partially infested Cache Valley by 1912 (Titus, 1913). The alfalfa weevil has become one of the more important insect problems currently affecting American agriculture. Recently, this problem has attracted national attention because of the development of resistance to insecticides by the alfalfa weevil, the outlawing of certain pesticides for use on forage crops and the rapid spread of the alfalfa weevil to new areas. With this increased attention, many discrepancies have appeared in different reports of the alfalfa weevil\u27s biology. The results of studies in the eastern United States often do not agree with those of studies which were made in Utah and vicinity during the early part of this century. In order to investigate the discrepancies or differences, and to determine the behavior patterns of the alfalfa weevil in Cache Valley, this study was undertaken. It was conducted from June, 1965 to August, 1966. The main topics investigated were the adult alfalfa weevil\u27s flight activities, reproduction, daily field activities, seasonal history including diapause, and respiration under controlled conditions

Correlations and contrasts in structural history and style between an Archaean greenstone belt and adjacent gneiss belt, NE Minnesota

An analysis of the deformation along the boundary between the Vermilion Granitic Complex (VGC) and the Vermilion district indicates that the two terranes have seen a similar deformation history since the earliest stages of folding in the area. Despite this common history, variations in structural style occur between the two terranes, such as the relative development of D sub 1 fabrics and D sub 2 shear zones, and these can be attributed to differences in the crustal levels of the two terranes during the deformation. Similarly, the local development of F sub 3 folds in the VGC, but not in the Vermilion district, is interpreted to be a result of later-D sub 2 pluton emplacement which was not significant at the level of exposure of ther Vermilion district

The use of orbitals and full spectra to identify misalignment

In this paper, a SpectraQuest demonstrator is used to introduce misalignment in a rotating set-up. The vibrations caused by misalignment is measured with both accelerometers on the bearings and eddy current probes on the shaft itself. A comparison is made between the classical spectral analysis, orbitals and full spectra. Orbitals are used to explain the physical interpretation of the vibration caused by misalignment. Full spectra allow to distinguish unbalance from misalignment by looking at the forward and reversed phenomena. This analysis is done for different kinds of misalignment, couplings, excitation forces and combined machinery faults

An Analysis Of Self-Efficacy, Welfare Status, And Occupational Choice Among Female Single Parents

The concept of self-efficacy has been proposed as a possible explanation why women are deterred from pursuing higher paying, traditionally male occupations. This study sampled 199 women pursuing occupational training in Vocational-Technical Institutes to obtain some measure of occupational self-efficacy and compare those measures by non-traditional occupational training and welfare status

Characterization of photomultiplier tubes in a novel operation mode for Secondary Emission Ionization Calorimetry

Hamamatsu single anode R7761 and multi-anode R5900-00-M16 Photomultiplier Tubes have been characterized for use in a Secondary Emission (SE) Ionization Calorimetry study. SE Ionization Calorimetry is a novel technique to measure electromagnetic shower particles in extreme radiation environments. The different operation modes used in these tests were developed by modifying the conventional PMT bias circuit. These modifications were simple changes to the arrangement of the voltage dividers of the baseboard circuits. The PMTs with modified bases, referred to as operating in SE mode, are used as an SE detector module in an SE calorimeter prototype, and placed between absorber materials (Fe, Cu, Pb, W, etc.). Here, the technical design of different operation modes, as well as the characterization measurements of both SE modes and the conventional PMT mode are reported

Grit at work

Grit—the tendency to pursue especially long-term goals with both passion and perseverance—has been shown to predict high achievement in a range of individual performance domains. We make a case for introducing the concept of grit to the organizational behavior literature. To begin, we elaborate the conceptual foundations of grit, highlighting ways in which grit differs from related traits and situating grit in the broader literature on goal pursuit. We then discuss three organizational antecedents—leadership, culture, and job design—that can encourage grit at work. Next, we discuss how and under what circumstances encouraging grit can improve workplace outcomes such as employee retention, work engagement, and job performance. We conclude with suggestions for future research at the intersection of psychology and organizational behavior