An Interactive Game Approach to Learning in Historical Geology and Paleontology

This article describes an interactive game that can be used in conjunction with traditional laboratory work, group discussions, student presentations, and writing exercises. It provides an enjoyable and motivating dimension to a university seminar/lab course in Historical Geology and Paleontology. A simple spelling-bee-type game evolves over ten weeks into a room-sized board game based on the geologic time scale. The game helps students learn fossil morphology, identification, classification, and paleoecology while illustrating the occurrences of important fossil groups, sea level fluctuations, and orogenic events through time. It also serves as an effective means for evaluating student progress in the laboratory. Although the game content is designed for geology majors in a university setting, the time scale game board can easily be adapted to a secondary school environment. Educational levels: Graduate or professional

Thermodynamics of pseudospin-electron model in mean field approximation

The mean field type approach based on the self-consistent consideration of an effective field created by electron transfer is developed for a description of thermodynamics of the Hubbard type models with an infinitely large on-site repulsion. This procedure, formulated by Izyumov et al, is an extension of the recently proposed generalized random phase approximation(GRPA). Within this approach, the thermodynamic properties of the two-sublattice pseudospin-electron model (the Hubbard model with local anharmonicity) are studied. Such a model can be used for a description of dielectric properties of YBaCuO-type superconductors along c-axis; pseudospins represent anharmonic motions of apical oxygens O4. It is shown that there are either phase transitions in the model with jumps of the mean values of a pseudospin and of electron concentration (in the $\mu=const$ regime) or the phase separation (in the $n=const$ regime). The phase transitions or phase separation are caused by pseudospin-pseudospin interaction as well as by electron transfer (the latter results in appearing of effective interaction between pseudospins). The possibility of the ferroelectric type ordering of pseudospins is investigated.Comment: 17 pages, 7 figure

A hypersonic research vehicle to develop scramjet engines

Four student design teams produced conceptual designs for a research vehicle to develop the supersonic combustion ramjet (scramjet) engines necessary for efficient hypersonic flight. This research aircraft would provide flight test data for prototype scramjets that is not available in groundbased test facilities. The design specifications call for a research aircraft to be launched from a carrier aircraft at 40,000 feet and a Mach number of 0.8. The aircraft must accelerate to Mach 6 while climbing to a 100,000 foot altitude and then ignite the experimental scramjet engines for acceleration to Mach 10. The research vehicle must then be recovered for another flight. The students responded with four different designs, two piloted waverider configurations, and two unmanned vehicles, one with a blended body-wing configuration, the other with a delta wing shape. All aircraft made use of an engine database provided by the General Electric Aircraft Engine Group; both turbofan ramjet and scramjet engine performance using liquid hydrogen fuel was available. Explained here are the students' conceptual designs and the aerodynamic and propulsion concepts that made their designs feasible

Making the best of mixed-field orientation of polar molecules: A recipe for achieving adiabatic dynamics in an electrostatic field combined with laser pulses

We have experimentally and theoretically investigated the mixed-field orientation of rotational-state-selected OCS molecules and we achieve strong degrees of alignment and orientation. The applied moderately intense nanosecond laser pulses are long enough to adiabatically align molecules. However, in combination with a weak dc electric field, the same laser pulses result in nonadiabatic dynamics in the mixed-field orientation. These observations are fully explained by calculations employing, both, adiabatic and non-adiabatic time-dependent models.Comment: 5 pages, 4 figure