12,857 research outputs found
Status of carbon sequestration projects in Africa: potential benefits and challenges to scaling up
Comparison of ground based and TOMS measurements of SO2 from volcanic emissions
The Brewer Ozone Spectrometer is being used in the World Ozone Network to monitor ozone and SO sub 2. SO sub 2 from natural as well as anthropogenic sources are measured. It has been demonstrated that SO sub 2 interferes with total ozone values as measured by the Dobson Spectrophotometer and the Total Ozone Mapping Spectrometer (TOMS). A small amount of manmade SO sub 2 is difficult to detect and quantify by TOMS because it is located near the surface. However, larger amounts of SO sub 2 injected into the stratosphere from volcanic emissions are detected by TOMS
The Greater Sum of Collaboration: Adding Value to Mathematics Education Through Teamwork
The role of a Mathematics Specialist can vary from pre-K through grade 8 schools. One of the most distinguishing factors involves the relationship between the Mathematics Specialists, administrators, and teachers. In this article, we share our experiences in a school culture that supports common language, collective commitments, trust, and transparency. Using this model, we have experienced high levels of teacher professionalism and student success. As lifelong learners, we continually reflect upon our practices and look for ways to meet the needs of our students. This occurs by implementing purposeful meeting structures that allow us to facilitate discussions around mathematics content, lesson planning, assessment results, and student progress. Administrators Brian Butler and Diane Kerr, along with Mathematics Specialists Tracey Hulen and Jennifer Deinhart, have formed a powerful relationship at Mason Crest Elementary School. This is a Title I school with 560 students, pre-K through grade 5, which promotes reflective practices and allows for flexibility and creativity as we continue to strengthen and improve our practices. Together, we share a story of our collaborative journey with teachers and students to create an effective mathematics program that embraces a conceptual learning philosophy. Ultimately there are two kinds of schools: learning-enriched schools and learning impoverished schools. I have yet to see a school where the learning curves ... of the adults were steeped upward and those of the students were not. Teachers and students go hand in hand as learners ... or they don\u27t go at all. [1] Roland Barth, Hand in Hand, We All Lear
CANOZE measurements of the Arctic ozone hole
In CANOZE 1 (Canadian Ozone Experiment), a series of 20 ozone profile measurements were made in April, 1986 from Alert at 82.5 N. CANOZE is the Canadian program for study of the Arctic winter ozone layer. In CANOZE 2, ozone profile measurements were made at Saskatoon, Edmonton, Churchill and Resolute during February and March, 1987 with ECC ozonesondes. Ground based measurements of column ozone, nitrogen dioxide and hydrochloric acid were conducted at Saskatoon. Two STRATOPROBE balloon flights were conducted on February 26 and March 19, 1987. Two aerosol flights were conducted by the University of Wyoming. The overall results of this study will be reported and compared with the NOZE findings. The results from CANOZE 3 in 1988, are also discussed. In 1988, as part of CANOZE 3, STRATOPROBE balloon flights were conducted from Saskatchewan on January 27 and February 13. A new lightweight infrared instrument was developed and test flown. A science flight was successfully conducted from Alert (82.5 N) on March 9, 1988 when the vortex was close to Alert; a good measurement of the profile of nitric acid was obtained. Overall, the Arctic spring ozone layer exhibits many of the features of the Antarctic ozone phenomenon, although there is obviously not a hole present every year. The Arctic ozone field in March, 1986 demonstrated many similarities to the Antarctic ozone hole. The TOMS imagery showed a crater structure in the ozone field similar to the Antarctic crater in October. Depleted layers of ozone were found in the profiles around 15 km, very similar to those reported from McMurdo. Enhanced levels of nitric acid were measured in air which had earlier been in the vortex. The TOMS imagery for March 1987 did not show an ozone crater, but will be examined for an ozone crater in February and March, 1988, the target date for the CANOZE 3 project
Preliminary flight evaluation of an engine performance optimization algorithm
A performance seeking control (PSC) algorithm has undergone initial flight test evaluation in subsonic operation of a PW 1128 engined F-15. This algorithm is designed to optimize the quasi-steady performance of an engine for three primary modes: (1) minimum fuel consumption; (2) minimum fan turbine inlet temperature (FTIT); and (3) maximum thrust. The flight test results have verified a thrust specific fuel consumption reduction of 1 pct., up to 100 R decreases in FTIT, and increases of as much as 12 pct. in maximum thrust. PSC technology promises to be of value in next generation tactical and transport aircraft
Pion-Nucleus Scattering at Medium Energies with Densities from Chiral Effective Field Theories
Recently developed chiral effective field theory models provide excellent
descriptions of the bulk characteristics of finite nuclei, but have not been
tested with other observables. In this work, densities from both relativistic
point-coupling models and mean-field meson models are used in the analysis of
meson-nucleus scattering at medium energies. Elastic scattering observables for
790
MeV/ on Pb are calculated in a relativistic impulse
approximation, using the Kemmer-Duffin-Petiau formalism to calculate the
nucleus optical potential.Comment: 9 page
The energy budget in Rayleigh-Benard convection
It is shown using three series of Rayleigh number simulations of varying
aspect ratio AR and Prandtl number Pr that the normalized dissipation at the
wall, while significantly greater than 1, approaches a constant dependent upon
AR and Pr. It is also found that the peak velocity, not the mean square
velocity, obeys the experimental scaling of Ra^{0.5}. The scaling of the mean
square velocity is closer to Ra^{0.46}, which is shown to be consistent with
experimental measurements and the numerical results for the scaling of Nu and
the temperature if there are strong correlations between the velocity and
temperature.Comment: 5 pages, 3 figures, new version 13 Mar, 200
Modeling the non-recycled Fermi gamma-ray pulsar population
We use Fermi Gamma-ray Space Telescope detections and upper limits on
non-recycled pulsars obtained from the Large Area Telescope (LAT) to constrain
how the gamma-ray luminosity L depends on the period P and the period
derivative \dot{P}. We use a Bayesian analysis to calculate a best-fit
luminosity law, or dependence of L on P and \dot{P}, including different
methods for modeling the beaming factor. An outer gap (OG) magnetosphere
geometry provides the best-fit model, which is L \propto P^{-a} \dot{P}^{b}
where a=1.36\pm0.03 and b=0.44\pm0.02, similar to but not identical to the
commonly assumed L \propto \sqrt{\dot{E}} \propto P^{-1.5} \dot{P}^{0.5}. Given
upper limits on gamma-ray fluxes of currently known radio pulsars and using the
OG model, we find that about 92% of the radio-detected pulsars have gamma-ray
beams that intersect our line of sight. By modeling the misalignment of radio
and gamma-ray beams of these pulsars, we find an average gamma-ray beaming
solid angle of about 3.7{\pi} for the OG model, assuming a uniform beam. Using
LAT-measured diffuse fluxes, we place a 2{\sigma} upper limit on the average
braking index and a 2{\sigma} lower limit on the average surface magnetic field
strength of the pulsar population of 3.8 and 3.2 X 10^{10} G, respectively. We
then predict the number of non-recycled pulsars detectable by the LAT based on
our population model. Using the two-year sensitivity, we find that the LAT is
capable of detecting emission from about 380 non-recycled pulsars, including
150 currently identified radio pulsars. Using the expected five-year
sensitivity, about 620 non-recycled pulsars are detectable, including about 220
currently identified radio pulsars. We note that these predictions
significantly depend on our model assumptions.Comment: 26 pages, 10 figures, Accepted by ApJ on 8 September 201
Letters between Frances B. Hatcher and W. J. Kerr
Letters concerning a position in the mathematics department at Utah Agricultural College
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