11,075 research outputs found

    Organs and universities: a universal association?

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    Short essay on the association between organs and universitie

    The PAX 2 picture processing system

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    PAX 2 digital picture processing program written in FORTRAN - subroutine annotation

    Do musical works contain an implied listener? Towards a theory of musical listening

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    This study presents the sketch of a theory of musical listening based on historical considerations of the role of music in Western culture. A universal element of musical listening might lie in the notion that all music is the product of a fundamental human capacity to hear, harnessed in countless ways by diverse cultures. Secondly, there is the type of music, covering very broad historical and cultural boundaries, that presupposes attentive listening or even a participating audience; this is perhaps the simplest and most familiar category, at least in the West. Finally, there is the range of music that might contain an 'implied listener', something which I suggest is much more elusive, with specific historical and cultural boundaries within Western modernity. While this sense of the implied listener - someone developing the sense of a consistent and unitary self over time - is understandable today and might well still be employed in a broad range of new music, I would suggest that it now reflects only one way of being human among an alarmingly broad array of choices

    Further Exploration of Optical/Thermal Interaction Effects on High-Power Laser System Performance and Optimization Through Multiphysics System-Level Modeling

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    High-power laser systems (HPLS) have wide-ranging applications in many prominent areas. HPLS use laser diodes to pump fiber gain media. Understanding the functionality of both components is critical for achieving effective HPLS operation. System optical efficiency is a function of diode junction temperature. As junction temperature changes, the wavelength spectrum of the diode output shifts causing optical power losses in the fiber gain media. Optical/thermal interactions of the dynamically coupled laser diodes and fiber gain media are not fully understood. A system level modeling approach considering the interactions between optical performance and component temperature is necessary. Four distinct models were created: Diode optical, diode thermal, fiber optical, and fiber thermal. Dynamically coupling these models together provided the capability to demonstrate how HPLS electro-to-optical efficiency changes when the laser diode pump spectrum shifts due to various levels of thermal management. Subsequent studies were done to determine which parameters across all four models had the most significant impact on laser performance from a designer’s perspective. Next, a statistical surrogate model was created by varying these parameters to create a parameter space. Response variables of interest were then reduced to a single equation as a function of these important parameters across the parameter space, allowing for quicker exploration of the potential design space. Lastly, laser time to steady state and laser efficiency were employed to determine when a specific diode cooling method should be used to achieve the highest laser efficiency. Understanding the optical/thermal interactions of laser operation and exploring the impact of various thermal capabilities can provide better system design and optimization guidelines. Bridging the gap between the optical and thermal aspects of laser operation in pursuit of such understanding has been made possible by the research herein

    Laser diagnostics for NTP fuel corrosion studies

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    Viewgraphs and explanations on laser diagnostics for nuclear thermal propulsion (NTP) fuel corrosion studies are presented. Topics covered include: NTP fuels; U-Zr-C system corrosion products; planar laser-induced fluorescence (PLIF); utilization of PLIF for corrosion product characterization of nuclear thermal rocket fuel elements under test; ZrC emission spectrum; and PLIF imaging of ZrC plume

    An Examination of the Variability of Migratory Timing Statistics Estimated From Catch and Effort Observations

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    The estimate of the mean arrival time based on catch or CPUE of fishes migrating into a fixed harvest area is a function of the number of days fished. Simulation studies using chinook salmon catch and effort data from the Yukon River delta, Alaska indicate that fishing effort concentrated at the tails of the migratory distribution which would tend to erroneously weigh the estimated mean arrival time in the direction of the sample, away from the true mean, is only a significant problem when the number of days open to fishing is small, covering less than 12% of the total duration of the migration. At sampling rates of the time domain greater than 12%, estimated mean arrival times are usually within 50% of the true mean. The variance of the ratio estimator and the mean square error (biased MSE) for the ratio estimator both allow for the construction of confidence limits for an estimated arrival time based on commercial catch and CPUE data. Arrival time estimates for migrations with large variances and with fewer than 12% of the time domain of the migration sampled have narrower 95% confidence intervals than the same methods produced for arrival time estimates for migrations of small variances. The variance of the ratio estimator is more conservative with sampling rates below 12%, however, it closely matches the biased MSE when sampling greater than 12% of the time domain of the migration. Once about a quarter of the migratory time span is fished, the confidence interval is greatly reduced. This is particularly true for migrations of small variance where the proportions of the population sampled tend to be quite concentrated about the central mass of the time distribution of abundance. Sampling from the average empirical proportion of catch yields a narrower confidence interval on the mean arrival time than does sampling from CPUE data. However, samples from annual daily proportions of CPUE with broader variances yield stronger confidence in arrival time estimates than do samples from migrations of average to small variances

    Alternative Buffer-Layers for the Growth of SrBi2Ta2O9 on Silicon

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    In this work we investigate the influence of the use of YSZ and CeO2/YSZ as insulators for Metal- Ferroelectric-Insulator-Semiconductor (MFIS) structures made with SrBi2Ta2O9 (SBT). We show that by using YSZ only the a-axis oriented Pyrochlore phase could be obtained. On the other hand the use of a CeO2/YSZ double-buffer layer gave a c-axis oriented SBT with no amorphous SiO2 inter- diffusion layer. The characteristics of MFIS diodes were greatly improved by the use of the double buffer. Using the same deposition conditions the memory window could be increased from 0.3 V to 0.9 V. From the piezoelectric response, nano-meter scale ferroelectric domains could be clearly identified in SBT thin films.Comment: 5 pages, 9 figures, 13 refernece

    An Extended Radio Counterpart of TeV J2032+4130?

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    We carried out a 5-pointing mosaic observation of TeV J2032+4130 at 1.4 and 4.8 GHz with the VLA in April of 2003. The analysis of the 4.8GHz data indicate weak wispy shell-like radio structure(s) which are at least partially non-thermal. The radio data is compatible with one or more young supernova remnants or perhaps the signature of large scale cluster shocks in this region induced by the violent action of the many massive stars in Cyg OB2.Comment: Proc. 1st GLAST Symp. Feb 5-8, 2007, Stanford C
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