156,796 research outputs found
The Theory of Steady, One-dimensional, Laminar Flame Propagation for One-step Chemical Reactions
The Theory of Steady, One-dimensional, Laminar Flame Propagation for One-step Chemical Reactions. The present status of the theory of one-dimensional, steady, laminar flame propagation for one-step chemical reactions is reviewed with particular emphasis on methods of solution and on the physical processes that dominate observable results
Crystal growing by electrodeposition from dense gaseous solutions
Single crystals and dendritic formations of silver are grown on platinum electrodes by electrodeposition from a dense gaseous solution of silver nitrate in ammonia. Process is modification of hydrothermal process, and also differs from standard electrodeposition by permitting single crystals to be grown from hydrogen-bonded solvents
On direction of spontaneous magnetization in a "cubic" ferromagnet
The magnetic properties of anisotropic films have been studied using
3D-neutron polarization analysis. The experimental facts refer to essential
distinction of the sample states, magnetized in opposite directions. For an
explanation of asymmetrical effects the model is offered, in which the
fundamental theoretical principles of structural phase transitions are used.Comment: 4 pages LaTeX (phbauth) and 4 figures (epsfig
VLA observations of a sample of galaxies with high far-infrared luminosities
Preliminary results are presented from a radio survey of galaxies detected by the IRAS minisurvey. It was found that the main difference between galaxies selected in the far infrared and those selected in the optical is that the former have higher radio luminosities and that the radio emission is more centrally concentrated. There is some evidence that the strong central radio sources in the galaxies selected in the infrared are due to star formation, the star formation rate divided by the volume in which the star formation is occuring is 100 to 1000 times greater in the galaxies selected in the infrared than in the disks of normal galaxies
Effects of Anisotropy in QED3 from Dyson-Schwinger equations in a box
We investigate the effect of anisotropies in the fermion velocities of 2+1
dimensional QED on the critical number N_f^c of fermions for dynamical mass
generation. Our framework are the Dyson-Schwinger equations for the gauge boson
and fermion propagators formulated in a finite volume. In contrast to previous
Dyson-Schwinger studies we do not rely on an expansion in small anisotropies
but keep the full velocity dependence of fermion equations intact. As result we
find sizable variations of N_f^c away from the isotropic point in agreement
with other approaches. We discuss the relevance of our findings for models of
high-T_c superconductors.Comment: 9 pages, 7 figures, v2: minor changes, typos corrected, version
accepted by PR
MULTIPRODUCT PRODUCTION CHOICES AND PESTICIDE REGULATION IN GEORGIA
An increasing emphasis on surface and groundwater quality and food safety may result in some form of pesticide regulations. A restricted profit function model of Georgia agriculture is used to examine the short-run effects of 2 and 5 percent reductions in all pesticides. Point estimates of short-run impacts, along with their 90 percent confidence intervals are presented.Agricultural and Food Policy,
Evaluation of the usefulness of a computer‐based learning program to support student learning in pharmacology
This study aims to evaluate the effectiveness of a computer‐based teaching program in supporting and enhancing traditional teaching methods. The program covers the pharmacology of inflammation and has been evaluated with a group of second‐year medical students at a UK university. The study assessed subject‐specific knowledge using a pre‐ and post‐test and surveyed, by questionnaire, students’ perceptions of the usefulness of the program to support learning before and after use. The use of computers for learning amongst this cohort of students was widespread. The results demonstrated an increase in students ‘ knowledge of the pharmacology of inflammation, coupled with a positive attitude towards the CBL program they had used and the advantages that this mode of study may provide in enabling students to manage their own learning. However, students did not feel that the program could substitute for traditional teaching (lectures)
Monitoring corn harvest progress from ERTS-1, southern Finney County, Kansas
The author has identified the following significant results. Comparison of ERTS-1 imagery of three dates reveals that corn harvesting is detectable by observing tonal change associated with the change from photosynthetically active plants to bare ground
Molecular dynamics simulations of oxide memristors: crystal field effects
We present molecular-dynamic simulations of memory resistors (memristors)
including the crystal field effects on mobile ionic species such as oxygen
vacancies appearing during operation of the device. Vacancy distributions show
different patterns depending on the ratio of a spatial period of the crystal
field to a characteristic radius of the vacancy-vacancy interaction. There are
signatures of the orientational order and of spatial voids in the vacancy
distributions for some crystal field potentials. The crystal field stabilizes
the patterns after they are formed, resulting in a non-volatile switching of
the simulated devices.Comment: 9 pages, 3 figure
Topic Maps as a Virtual Observatory tool
One major component of the VO will be catalogs measuring gigabytes and
terrabytes if not more. Some mechanism like XML will be used for structuring
the information. However, such mechanisms are not good for information
retrieval on their own. For retrieval we use queries. Topic Maps that have
started becoming popular recently are excellent for segregating information
that results from a query. A Topic Map is a structured network of hyperlinks
above an information pool. Different Topic Maps can form different layers above
the same information pool and provide us with different views of it. This
facilitates in being able to ask exact questions, aiding us in looking for gold
needles in the proverbial haystack. Here we discuss the specifics of what Topic
Maps are and how they can be implemented within the VO framework.
URL: http://www.astro.caltech.edu/~aam/science/topicmaps/Comment: 11 pages, 5 eps figures, to appear in SPIE Annual Meeting 2001
proceedings (Astronomical Data Analysis), uses spie.st
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