Electron-impact excitation of diatomic hydride cations I: HeH+^+, CH+^+, ArH+^+

{\bf R}-matrix calculations combined with the adiabatic nuclei approximation are used to compute electron-impact rotiational excitation rates for three closed-shell diatomic cations, HeH$^+$, CH$^+$, ArH$^+$. Comparisons with previous studies show that an improved treatment of threshold effects leads to significant changes in the low temperature rates, furthermore the new calculations suggest that excitation of CH$^+$ is dominated by $\Delta J =1$ transitions as is expected for cations with a large dipole moment. A model for ArH$^+$ excitation in the Crab Nebula is presented which gives results consistent with the observations for electron densities in the range $2-3\times 10^3$~cm$^{-3}$.Comment: MNRAS submitted 7 pages, 9 figure

Multi-objective/loading optimization for rotating composite flexbeams

With the evolution of advanced composites, the feasibility of designing bearingless rotor systems for high speed, demanding maneuver envelopes, and high aircraft gross weights has become a reality. These systems eliminate the need for hinges and heavily loaded bearings by incorporating a composite flexbeam structure which accommodates flapping, lead-lag, and feathering motions by bending and twisting while reacting full blade centrifugal force. The flight characteristics of a bearingless rotor system are largely dependent on hub design, and the principal element in this type of system is the composite flexbeam. As in any hub design, trade off studies must be performed in order to optimize performance, dynamics (stability), handling qualities, and stresses. However, since the flexbeam structure is the primary component which will determine the balance of these characteristics, its design and fabrication are not straightforward. It was concluded that: pitchcase and snubber damper representations are required in the flexbeam model for proper sizing resulting from dynamic requirements; optimization is necessary for flexbeam design, since it reduces the design iteration time and results in an improved design; and inclusion of multiple flight conditions and their corresponding fatigue allowables is necessary for the optimization procedure

Theatrical Space

Theatrical Spac

Optimizing tone production on a 300 spot per inch laser printer

Digital halftones as output on plain paper are the focus of this study. A new terminology is suggested to allow proper description of digital halftones. The most important of these terms is the use of addressability to replace the often misused term resolution. Also important is the use of the term spot rather than dot to describe addressability. A means of properly describing digital halftones is suggested to avoid confusion with analog (ie., conventional photographic) halftones. Halftone patterns were created to test the efficiency of different designs at 300 spot per inch addressability on a laser printer. The page description language PostScript was used to create the halftone patterns which were modeled on three basic designs. It has been established that two halftone dot patterns constructed on the same matrix and containing the same number of spots will produce different densities if the configuration of the spots within the matrix is different This has been tested by comparing the results of the tone production curves of the condensed and open halftone dot designs. These patterns were output on a laser printer and measured for density. Tone production curves were drawn and compared. Even though each matrix contains the same number of spots, it has been shown that different densities result. This is solely a consequence of the dot design. Microscopic studies were conducted to illustrate the nature of the filling-in in the non-image area. Microscopic measurements were also made to ascertain the size of an individual spot at various screen rulings. It was found that the spot, which was very irregular to begin with, actually began to break up as the linescreen approached 150 lines per inch. Paper tests were run to gauge the maximum density and the tone production capabilities of various papers. Although the results were inconclusive, they point out another flaw of digital halftones which are output on plain paper. The number of grays predictable, given a matrix size, is greater than what is achievable in practice. These results mean the following for designers of digital halftones. First, purely due to the nature of digital halftones, the highlight and shadow areas will be most difficult to control. Secondly, use of a screen angle can limit the filling-in in the tone production curve. Thirdly, the variability of the spot size on paper, and its irregularities must be closely observed to assure that these dot forms will be reproducible in the lithographic process if this is desired. And finally, careful planning in the design of a halftone dot may allow an improved tone production curve

Aesthetic and Artistic Verdicts

In this article I propose a way of thinking about aesthetic and artistic verdicts that would keep them distinct from one another. The former are reflections of the kinds of things we prefer and take pleasure in; the latter are reflections of other judgments we make about the kinds of achievements that are made in works of art. In part to support this view of verdicts, I also propose a way of keeping distinct the description, the interpretation, and the evaluation of works of art. (And along the way, I worry about whether we offer the same kinds of interpretations of the objects of our aesthetic pleasures, properly considered, that we clearly do offer with respect to works of art.) The thesis I propose—the achievement model—is not original with me. What is original, perhaps, is that it is posed as an alternative to two other views of artistic evaluation, namely the appeal to “ideal critics” and the appeal to one way of understanding our preferences with regard to works of art. I do not attempt to show that each of these alternatives meets with insuperable problems; but I do indicate what I take to be the substantive content of those problems. In the end, in order to flesh out the thesis I propose, I borrow some material from the literature on human well-being concerning how we determine what an achievement is

The Use of Plenoptic Cameras in Astronomy

Since light-field imaging cameras are starting to become more in the world today, the question that arises is, “Could these cameras help advance the science when they are used in conjunction with telescopes and microscopes?” With their use in microscopy having been partially settled and no information about their use with telescopes, this experiment was setup to start the ascertainment of the use of light-field imaging cameras with telescopes. With the use of an older plenoptic camera, it was ascertained that a new light-field imaging camera might compare with the conventional digital camera of today

DETERMINING THE EFFECTS OF LAND CHARACTERISTICS ON FARMLAND VALUES IN SOUTH-CENTRAL IDAHO

This study focused on evaluating the effects of different attributes that impact irrigated farmland values in South-central Idaho. Results indicate that study area farmland values are largely determined by agricultural productivity (profiability) related factors. However, estimated "development increment values" for parcels that seemed to be under development pressure in the study area are explainable by nonagricultural variables.Land Economics/Use,