3,042 research outputs found
Development of 2 underseat energy absorbers for application to crashworthy passenger seats for general aviation aircraft
This report presents the methodology and results of a program conducted to develop two underseat energy absorber (E/A) concepts for application to nonadjustable crashworthy passenger seats for general aviation aircraft. One concept utilizes an inflated air bag, and the other, a convoluted sheet metal bellows. Prototypes of both were designed, built, and tested. Both concepts demonstrated the necessary features of an energy absorber (load-limiter); however, the air bag concept is particularly encouraging because of its light weight. Several seat frame concepts also were investigated as a means of resisting longitudinal and lateral loads and of guiding the primary vertical stroke of the underseat energy absorber. Further development of a seat system design using the underseat energy absorbers is recommended because they provide greatly enhanced crash survivability as compared with existing general aviation aircraft seats
The GEMPAK Barnes objective analysis scheme
GEMPAK, an interactive computer software system developed for the purpose of assimilating, analyzing, and displaying various conventional and satellite meteorological data types is discussed. The objective map analysis scheme possesses certain characteristics that allowed it to be adapted to meet the analysis needs GEMPAK. Those characteristics and the specific adaptation of the scheme to GEMPAK are described. A step-by-step guide for using the GEMPAK Barnes scheme on an interactive computer (in real time) to analyze various types of meteorological datasets is also presented
GEMPAK5 user's guide, version 5.0
GEMPAK is a general meteorological software package used to analyze and display conventional meteorological data as well as satellite derived parameters. The User's Guide describes the GEMPAK5 programs and input parameters and details the algorithms used for the meteorological computations
Rapidité de la vitesse d'altération des minéraux du sol en conditions ferrallitiques : méthode des minéraux-test
Les minéraux des sols sont soumis à des dissolutions et reprécipitations en fonction des conditions de milieu, et en particulier de l'activité biologique. Pour déterminer la cinétique des réactions mises en jeu dans le recyclage des éléments chimiques, des sachets de minéraux test contenant séparément de la gibbsite, deux types de kaolinite et un verre siliceux, ont été introduits dans les horizons supérieurs d'un sol ferrallitique de forêt amazonienne. Au bout de 6 mois, toutes les phases implantées ont été altérées, et d'autres minéraux, oxy-hydroxydes de fer et de titane, sont apparus. La réactivité des minéraux secondaires avec les conditions de milieu est donc rapide à l'échelle des temps pédologiques dans les sols étudiés. (Résumé d'auteur
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Professional development learning environments (PDLEs) embedded in a collaborative online learning environment (COLE): Moving towards a new conception of online professional learning
© 2018, Springer Science+Business Media, LLC, part of Springer Nature. Teaching, and education in general, remain firmly rooted in the practices of the past and continue to resist the implementation of strategies and theories arising from educational research. Consequently, significant reforms have been slow to take hold in educational systems around the world. Much of the reluctance can be attributed to a widely-held misconception of the nature of learning. This project attempts to address this misconception through the development of Professional Development Learning Environments (PDLEs are a series of learning tasks and a video-based case study) embedded in an online learning environment that requires the collaboration of users to solve problems. To use a Problem-Based-Learning (PBL) approach in an online context requires a major paradigm shift as well as using tools that were not designed specifically for such a student-driven, process-centred pedagogical paradigm. This becomes a problem when online resources and systems are used for supporting in-service teacher in their pursuit of furthering their education. Although the current theories of learning and teaching may present the philosophical content of such courses, the online strategies used often conflict with the theory. To study the formal implementation of PBL as a social-constructivist pedagogical approach, into an online learning environment to provide the tools for e-learning that would be closer in design to the current thinking on the very nature of learning, the PDLEs were modified to become small reusable video clips with a structure designed to facilitate PBL and focus learners’ attention on higher order thinking skills rather than specifically on content. These modified PDLEs are referred to as Problem-Based Learning Objects (PBLOs). The PBLOs were embedded into a prototype of a Collaborative Online Learning Environment (COLE) which was developed simultaneously. The entire system was pilot tested with small groups. Preliminary results show that although many technical difficulties remain to be solved, using the environment does show evidence of some effect on beliefs about personal theories of learning, causing shifts from technical issues to those surrounding processes of learning. Our preliminary research has called attention to the potential ability of PBLO/COLE to disrupt conventional, transmission-based conceptions of online learning as content delivery. At the same time, however, our preliminary work has also indicated that learners who are not used to the collaborative opportunities provided within PBLO/COLE may still hold traditional orientations to teaching and learning as a “gold standard” to which all other options are compared. A purposeful direction for our future research will entail working with learners in PBLO/COLE over a sustained period so that they may engage in an online experience grounded in principles of socio-constructivism
Exploring X-ray Binary Populations in Compact Group Galaxies with
We obtain total galaxy X-ray luminosities, , originating from
individually detected point sources in a sample of 47 galaxies in 15 compact
groups of galaxies (CGs). For the great majority of our galaxies, we find that
the detected point sources most likely are local to their associated galaxy,
and are thus extragalactic X-ray binaries (XRBs) or nuclear active galactic
nuclei (AGNs). For spiral and irregular galaxies, we find that, after
accounting for AGNs and nuclear sources, most CG galaxies are either within the
scatter of the Mineo et al. (2012) - star formation rate
(SFR) correlation or have higher than predicted by this correlation for
their SFR. We discuss how these "excesses" may be due to low metallicities and
high interaction levels. For elliptical and S0 galaxies, after accounting for
AGNs and nuclear sources, most CG galaxies are consistent with the Boroson et
al. (2011) - stellar mass correlation for low-mass XRBs, with larger
scatter, likely due to residual effects such as AGN activity or hot gas.
Assuming non-nuclear sources are low- or high-mass XRBs, we use appropriate XRB
luminosity functions to estimate the probability that stochastic effects can
lead to such extreme values. We find that, although stochastic effects do
not in general appear to be important, for some galaxies there is a significant
probability that high values can be observed due to strong XRB
variability.Comment: Accepted by Ap
Atomic and Nuclear Effects in the Slow-Neutron Total Cross Section of Terbium
The total cross section of terbium has been measured for neutron energies En from 0.003 to 1.78 eV. For neutron energies above the Be cutoff a new method employing two crystal monochromators in series was used. For En ≲ 0.005 eV a single-crystal monochromator in conjunction with a Be filter was employed. Using earlier measurements of the radiative-capture cross section, the experimental results have been analyzed to include the contributions due to paramagnetic scattering, coherent scattering, and phonon effects. The analysis shows that the experiment and the calculations are consistent everywhere except 0.015 ≲ En ≲ 0.10 eV. In this energy range inelastic coherent scattering is not accurately accounted for with the use of Placzek\u27s incoherent approximations. In addition crystalline-field effects give rise to further complications. The comparison between the experiment and the calculations for 0.015 ≲ En ≲ 0.10 eV suggests that studies of coherent inelastic scattering and crystalline-field effects in terbium metal are needed. The experimental results for En ≳ 0.12 eV yield the potential scattering cross section as 7.5 ± 0.5 b. This corresponds to a spin-independent nuclear radius of 7.73 ± 0.27 fm and to a radius parameter of 1.43 ± 0.05 fm. The results suggest that the incoherent scattering cross section, if present, is very small (≲ 1.0 b)
Comparaison de techniques d’identification des Erwinia et des Pseudomonas responsables de la pourriture molle
Trois méthodes, soit la caractérisation physiologique, l'utilisation de systèmes miniaturisés d'identification (API 20E, API NFT et Biolog) et l'analyse du profil électrophorétique des protéines sécrétées, ont été expérimentées afin de déterminer une technique précise et rapide d'identification des Pseudomonas et des Erwinia responsables de la pourriture molle. L'analyse des patrons électrophorétiques des protéines sécrétées est une méthode très efficace pour identifier les différentes espèces pectinolytiques de Pseudomonas fluorescents. Le système Biolog reconnaît efficacement le P. marginalis et le P. viridiflava. Le système API NFT est efficace pour l'identification du P. marginalis, du P. viridiflava et du P. syringae. C'est le système API 20E qui s'est avéré le plus efficace pour l'identification des Erwinia. L'électrophorèse des protéines sécrétées et le système API NFT permettent une identification rapide et efficace des Pseudomonas, tandis que pour les Erwinia, seul le système API20E est performant.Three methods, namely physiological characterization, the use of miniaturized identification Systems (API 20E, API NFT, and Biolog) and the analysis of the electrophoretic profile of proteins secreted by the bacteria, were used in order to determine a precise and quick identification technique for the Pseudomonas and Erwinia species causing soft rots in several plant species. The analysis of the electrophoretic profile of the proteins secreted is a very efficient method of identification for the various pectinolytic species of fluorescent Pseudomonas. The Biolog System accurately recognizes P. marginalisand P. viridiflava. The API NFT System is efficient for the identification of P. marginalis, P. viridiflava and P. syringae. The API 20E System was found to be the most reliable System for identifying Erwinia species. The electrophoresis of proteins secreted and the API NFT system allow a quick and efficient identification of Pseudomonas species, while for Erwinia species, only the API 20E System is efficient
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