12,418 research outputs found
Investigation of electrochemistry of high energy compounds in organic electrolytes Third progress report, Nov. 1, 1965 - Apr. 30, 1966
Electrochemical properties, and chemical reactions between cyclic esters and certain metal
Investigation of electrochemistry of high energy compounds in organic electrolytes, May 1 - October 31, 1965
High energy compounds in organic electrolytes - electrochemical and chemical properties of cyclic esters, gamma butyrolactone, gamma valerolactone, and propylene carbonat
Investigation of electrochemistry of high energy compounds in organic electrolytes, november 1, 1964 - april 30, 1965
Conversion by electrochemical process of chemical to electrical energy - high energy compounds in organic electrolytes and cathode material
A Rotating Aperture Mask for Small Telescopes
Observing the dynamic interaction between stars and their close stellar neighbors is key to establishing the stars’ orbits, masses, and other properties. Our ability to visually discriminate nearby stars is limited by the power of our telescopes, posing a challenge to astronomers at small observatories that contribute to binary star surveys. Masks placed at the telescope aperture promise to augment the resolving power of telescopes of all sizes, but many of these masks must be manually and repetitively reoriented about the optical axis to achieve their full benefits. This paper introduces a design concept for a mask rotation mechanism that can be adapted to telescopes of different types and proportions, focusing on an implementation for a Celestron C11 Schmidt–Cassegrain optical tube assembly. Mask concepts were first evaluated using diffraction simulation programs, later manufactured, and finally tested on close double stars using a C11. An electronic rotation mechanism was designed, produced, and evaluated. Results show that applying a properly shaped and oriented mask to a C11 enhances contrast in images of double star systems relative to images captured with the unmasked telescope, and they show that the rotation mechanism accurately and repeatably places masks at target orientations with minimal manual effort. Detail drawings of the mask rotation mechanism and code for the software interface are included
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Renewable energy education and industrial arts : linking knowledge producers with knowledge users.
EducationDoctor of Education (Ed.D.
Tidal Disruption Event Host Galaxies in the Context of the Local Galaxy Population
We study the properties of tidal disruption event (TDE) host galaxies in the
context of a catalog of ~500,000 galaxies from the Sloan Digital Sky Survey. We
explore whether selection effects can account for the overrepresentation of
TDEs in E+A/post-starburst galaxies by creating matched galaxy samples.
Accounting for possible selection effects due to black hole (BH) mass, redshift
completeness, strong AGN presence, bulge colors, and surface brightness can
reduce the apparent overrepresentation of TDEs in E+A host galaxies by a factor
of ~4 (from ~100-190 to ~25-48), but cannot fully explain the
preference. We find that TDE host galaxies have atypical photometric properties
compared to similar, "typical" galaxies. In particular, TDE host galaxies tend
to live in or near the "green valley" between star-forming and passive
galaxies, and have bluer bulge colors ( mag), lower
half-light surface brightnesses (by ~1 mag/arcsec), higher Sersic indices
(), and higher bulge-to-total-light ratios () than galaxies with matched BH masses. We find that TDE host
galaxies appear more centrally concentrated and that all have high galaxy
Sersic indices and fractions---on average in the top 10% of galaxies of
the same BH mass---suggesting a higher nuclear stellar density. We identify a
region in Sersic index and BH mass parameter space that contains ~2% of our
reference catalog galaxies but of TDE host galaxies. The unique
photometric properties of TDE host galaxies may be useful for selecting
candidate TDEs for spectroscopic follow-up observations in large transient
surveys.Comment: 26 pages, 11 figures, 5 tables. Published in Ap
Correlation between the precipitation and energy production at hydropower plants to mitigate flooding in the Missouri River Basin
Thesis (S.B.)--Massachusetts Institute of Technology, Department of Mechanical Engineering, 2013.Cataloged from PDF version of thesis.Includes bibliographical references (pages 23).Currently, hydropower plants serve as one source of green energy for power companies. These plants are located in various geographical regions throughout the United States and can be split into three main classifications: run of river, basins, and reservoirs. The energy production at hydropower plants can vary on a monthly basis, and this change is recorded for company purposes. This study used data provided for five reservoir plants in the Missouri River Basin to model these variations, and determine a correlation between the precipitation and energy production. The parameters provided and modeled included the precipitation measured at each hydropower plant, the evaporation from the surface of the reservoir, the inflow into the reservoir, the outflow from each plant, the energy generation of each plant, and the reservoir elevation every month from June 1967 to December 2012. Using these monthly values, two separate models were created: a model that relates the power generation as determined from the energy production to the outflow and the effective hydraulic head at the hydropower plants, and a second model correlating the effective hydraulic head and the precipitation measured in the reservoir. The results showed that the energy production varied proportionally to the product of the monthly precipitation and outflow for each of the hydropower plants, up to the maximum installed capacity at each of the plants. Beyond this maximum installed power, there was no correlation between increased precipitation or outflow and the power produced.by Rachel Foley.S.B
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A comparison of traditional 6th - 8th grade middle schools and k - 8th grade academies in the areas of student achievement and school climate
textResearchers differ in their views of the structure of traditional middle and high schools in public education on student performance. They question the effectiveness of school and age level configuration, and its comparability with the age-appropriate cognitive, social and emotional development needs of students. Some believe that eliminating the traditional break between elementary and middle schools would enhance students' overall learning opportunities, particularly for ethnic minority and economically disadvantaged students and reduce the current disparity in student performance between traditional middle schools and K-8 academies. This research is founded on a study of (a) curricular and co-curricular richness of the core program; and (b) the organizational elements of the elementary and intermediate school configurations. This mixed-methods investigation utilized both quantitative and qualitative methods to develop the data. The quantitative method incorporated a comparison of six schools that were once either K-5 elementary schools or 6-8 traditional middle schools but were later reconfigured to encompass all grade levels making them K-8 Academies. The quantitative method was used to evaluate the quality of (a) student performance in mathematics and language arts as determined by state assessments (b) the school climate as perceived by the teachers, parents and community members. Creswell (2005) noted that the combination of quantitative and qualitative data gathering, analysis, and interviews strengthens the understanding of the problem and related research findings. Many school districts with 6-8 traditional middle schools have experienced students not making adequate progress and are considering changing their grade structure to K-8. DeJong and Craig (2002) list the reasons for this conversion to cause fewer transitions for students, to keep students in neighborhood schools, to reduce transportation costs, to improve safety, and to accommodate declining enrollment. The researcher hopes that, along with other current research, this study may serve to compel more school districts to consider adopting alternative grade configurations when students are not making adequate progress in the traditional 6-8 grade configuration.Educational Administratio
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