A theoretical and experimental study of low voltage, high current dc to ac converters which use either magnetoresistors, superconductors, Hall effect devices, or thin-film devices Final report

Low-voltage, high current dc-ac converter from magnetoresistor, superconductor, Hall effect, or thin-film device

Performance documentation of the engineering model 30-cm diameter thruster

The results of extensive testing of two 30-cm ion thrusters which are virtually identical to the 900 series Engineering Model Thruster in an ongoing 15,000-hour life test are presented. Performance data for the nominal fullpower (2650 W) operating point; performance sensitivities to discharge voltage, discharge losses, accelerator voltage, and magnetic baffle current; and several power throttling techniques (maximum Isp, maximum thrust/power ratio, and two cases in between are included). Criteria for throttling are specified in terms of the screen power supply envelope, thruster operating limits, and control stability. In addition, reduced requirements for successful high voltage recycles are presented

A fast data acquisition system for the study of transient events by high repetition rate time-of-flight mass spectrometry

Recent advances in commercially available data acquisition electronics embodying high speed A/D conversion coupled to increased memory storage have now made practical (at least within time intervals of a third of a millisecond or more) the capturing of all of the data generated by a high repetition rate time-of-flight mass spectrometer producing complete spectra every 25 to 35 microseconds. Such a system was assembled and interfaced with a personal computer for control and management of data. The applications are described for recording time-resolved spectra of individual vapor plumes induced from the pulsed-laser heating of material. Each laser pulse triggers the system to generate automatically a 3-dimensional (3-D) presentation of the time-resolved spectra with m/z labeling of the major mass peaks, plus an intensity versus time display of both the laser pulse and the resulting vapor pulse. The software also permits storing of data and its presentation in various additional forms

An Assessment of Integrated Flywheel System Technology

The current state of the technology in flywheel storage systems and ancillary components, the technology in light of future requirements, and technology development needs to rectify these shortfalls were identified. Technology efforts conducted in Europe and in the United States were reviewed. Results of developments in composite material rotors, magnetic suspension systems, motor/generators and electronics, and system dynamics and control were presented. The technology issues for the various disciplines and technology enhancement scenarios are discussed. A summary of the workshop, and conclusions and recommendations are presented

\u3cem\u3eAjax in Iraq\u3c/em\u3e Stage Management

Stage managing Ajax in Iraq was my introduction to Linfield Theatre. As a stage manager, I was able to explore all aspects of the show. In production meetings weekly we discussed the agenda for the week and what was planned to be done as the week went on. In the beginning weeks, we looked at costume sketches and discussed ideas for incorporating different visions and how to make them come to life onstage. As stage manager, I worked with designers, the tech crew, and actors. I quickly learned what my responsibilities were in rehearsal and made my best effort to do my job in a way that was the most beneficial to both the actors and the director, as well as communicating with the entire production team. With cue-to-cue, I learned how the collaboration between sound design, lighting design, costumes, and the directing vision shapes and creates the world of the play. I learned it is better to be safe than sorry; if you have an inkling that you might want something to happen in a certain place, it is best to insert a cue because it is less stressful to delete cues than it is to create them later on. During dry tech, I learned there are a lot of things that need to come together for the show to look nice and that there were many intermediate steps in which I wasn’t involved. Tech with actors was a whole new experience and another lesson in communication: keep the ball rolling but make sure everything is functioning the way it should. Tech ironed out the logistics of the play, and with the addition of actors there was a whole other group to communicate with. Teching the show and learning to call cues was perhaps the most exciting and most nerve-wracking part of the tech process. The teamwork of theatre is demonstrated throughout the entire process from sketches, to discussion, to rehearsal, to tech, and finally production nights, where all the hard work comes together. Knowing I have people depending on me for the show to go smoothly was a big responsibility and one that I am grateful to have experienced. Being the communication vein between the actors and the director as well as the design team helped to hone my communication skills and helped me develop an efficient way of getting information across. I learned to work with many different kinds of people and adapt in a way that got information across in a way that was most beneficial to them

Synopsis of a computer program designed to interface a personal computer with the fast data acquisition system of a time-of-flight mass spectrometer

Briefly described are the essential features of a computer program designed to interface a personal computer with the fast, digital data acquisition system of a time-of-flight mass spectrometer. The instrumentation was developed to provide a time-resolved analysis of individual vapor pulses produced by the incidence of a pulsed laser beam on an ablative material. The high repetition rate spectrometer coupled to a fast transient recorder captures complete mass spectra every 20 to 35 microsecs, thereby providing the time resolution needed for the study of this sort of transient event. The program enables the computer to record the large amount of data generated by the system in short time intervals, and it provides the operator the immediate option of presenting the spectral data in several different formats. Furthermore, the system does this with a high degree of automation, including the tasks of mass labeling the spectra and logging pertinent instrumental parameters

A 1000 hour endurance test of a glass-coated accelerator grid on a 15-centimeter-diameter Kaufman thruster

Endurance test of glass coated accelerator grid on 15-centimeter-diameter Kaufman thruste

Long-Term Potentiation: One Kind or Many?

Do neurobiologists aim to discover natural kinds? I address this question in this chapter via a critical analysis of classification practices operative across the 43-year history of research on long-term potentiation (LTP). I argue that this 43-year history supports the idea that the structure of scientific practice surrounding LTP research has remained an obstacle to the discovery of natural kinds