4,778 research outputs found
Administrative automation in a scientific environment
Although the scientific personnel at GSFC were advanced in the development and use of hardware and software for scientific applications, resistance to the use of automation or purchase of terminals, software and services, specifically for administrative functions was widespread. The approach used to address problems and constraints and plans for administrative automation within the Space and Earth Sciences Directorate are delineated. Accomplishments thus far include reduction of paperwork and manual efforts; improved communications through telemail and committees; additional support staff; increased awareness at all levels on ergonomic concerns and the need for training; better equipment; improved ADP skills through experience; management commitment; and an overall strategy for automating
Effects of cobalt in nickel-base superalloys
The role of cobalt in a representative wrought nickel-base superalloy was determined. The results show cobalt affecting the solubility of elements in the gamma matrix, resulting in enhanced gamma' volume fraction, in the stabilization of MC-type carbides, and in the stabilization of sigma phase. In the particular alloy studied, these microstructural and microchemistry changes are insufficient in extent to impact on tensile strength, yield strength, and in the ductilities. Depending on the heat treatment, creep and stress rupture resistance can be cobalt sensitive. In the coarse grain, fully solutioned and aged condition, all of the alloy's 17% cobalt can be replaced by nickel without deleteriously affecting this resistance. In the fine grain, partially solutioned and aged condition, this resistance is deleteriously affected only when one-half or more of the initial cobalt content is removed. The structure and property results are discussed with respect to existing theories and with respect to other recent and earlier findings on the impact of cobalt, if any, on the performance of nickel-base superalloys
Recalibrating the Wide-field Infrared Survey Explorer (WISE) W4 Filter
We present a revised effective wavelength and photometric calibration for the
Wide-field Infrared Survey Explorer (WISE) W4 band, including tests of
empirically motivated modifications to its pre-launch laboratory-measured
relative system response curve. We derived these by comparing measured W4
photometry with photometry synthesised from spectra of galaxies and planetary
nebulae. The difference between measured and synthesised photometry using the
pre-launch laboratory-measured W4 relative system response can be as large as
0.3 mag for galaxies and 1 mag for planetary nebulae. We find the W4 effective
wavelength should be revised upward by 3.3%, from 22.1 micron to 22.8 micron,
and the W4 AB magnitude of Vega should be revised from m = 6.59 to m = 6.66. In
an attempt to reproduce the observed W4 photometry, we tested three
modifications to the pre-launch laboratory-measured W4 relative system response
curve, all of which have an effective wavelength of 22.8 micron. Of the three
relative system response curve models tested, a model that matches the
laboratory-measured relative system response curve, but has the wavelengths
increased by 3.3% (or 0.73 micron) achieves reasonable agreement between the
measured and synthesised photometry.Comment: Accepted for publication in Publications of the Astronomical Society
of Australia, 6 pages, 4 figures, 1 tabl
X-Ray scattering study of cellulosic arrangements in plant cell wall materials
Plant cell walls are the most important source of the polymer cellulose. The cell wall contains crystalline cellulose microfibrils embedded in a matrix of amorphous polymers. The most important of these amorphous polymers are the lignins and the hemi-celluloses. In this thesis we concentrate on the use of wide angle x-ray scattering as a tool to understand the important arrangements of cellulose in cell walls. Other experimental tools are used to supplement this information
Investigating the Improvement in Science Achievement Among Fifth Grade Science Students When Using the Instructional Design Model
The purpose of this study is to determine if the Instructional Design Model will improve science achievement. The study addressed the problem of low science achievement among 93 Grade 5 students. The theoretical framework that was applied to this study was developed by Ralph Tyler in 1949. The researcher believed that Tyler’s four-process curriculum planning approach guided teachers to look differently at teaching and learning. This model assisted teachers in developing lessons that used the Instructional Design Model and produced objectives that reflect their classroom goals, impacted curriculum, and increased the understanding of science concepts. The school administered a multiple choice, twenty-item pretest a unit of instruction to the Grade 5 students.
The teachers participated in a pre-interview, received professional development on the Instructional Design Model, attended common planning meetings to develop lessons, delivered the lessons, and participated in a post-interview. The teachers taught a four-week unit and each teacher was observed every other week for one class period. After the four-week period the teacher administered the posttest to the students; which, was the same test as the pretest to the Grade 5 students. A convergent mixed methods design was used; in order to collect data in this type of design, the qualitative and quantitative data were collected in a lateral fashion, analyzed separately, and then merged together. An analysis of the data revealed the degree to which the use of Tyler’s Instructional Design Model in Grade 5 science classes in the target district would affect student achievement in science. The results of the elementary school’s scores were compared to the pre and post assessment data and determined that use of the Instructional Design Model significantly impacted post-test results
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