11,265 research outputs found

    Primary electric power generation systems for advanced-technology engines

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    The advantages of the all electric airplane are discussed. In the all electric airplane the generator is the sole source of electric power; it powers the primary and secondary flight controls, the environmentals, and the landing gear. Five candidates for all electric power systems are discussed and compared. Cost benefits of the all electric airplane are discussed

    A community of teachers: Using Activity Theory to investigate the implementation of ICTE in a remote Indigenous school

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    In 2001-2002, an innovative project entitled Reach In-Reach Out has been conducted in Far North Queensland. Its aim was to use telecommunications and Internet tools to facilitate communication between the children of Lockhart River who attend secondary school in such centres as Cairns, Townsville and Herberton and their families. This study was the first (of three) to investigate the impact of this project. Its focus is on the teachers of Lockart River State School and the changes made to their practice by the implementation of the project. The study described in this paper was conducted in Lockhart River which is situated on Kanthanumpu (Southern Kuuku Ya'u) land in Far North Queensland. The current population is estimated between 650 (Education Queensland, 2001a) and 800 (Lockhart River Land and Sea Management Agency, 2001) residents. The student population of Lockhart River State School in 2001was 26 (Kindy), 105 (Primary) and 30 (Alternate secondary/VET) programs) (Education Queensland, 2001a). At the end of 1999, the secondary school of Lockhart River was closed following a community decision to do so. This necessitated the majority of post-primary students having to leave Lockhart River to continue their education at boarding school. At the beginning of 2002, 38 students left the Lockhart River Community to attend boarding schools (and 8 remained to take part in the Alternate Secondary/VET program offered at the school). Table 1 details the secondary enrolments of Lockhart River students from 1998 to 2001, including the period covered by this study (2001)

    Study of spectral moments in semileptonic decays of the b hadron with the DELPHI detector at LEP

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    The measurement of the moments of hadronic mass spectrum and of lepton energy spectrum based on a sample of semileptonic decays of the b hadron selected from Z0→bbˉZ^0 \to b \bar b events recorded with the DELPHI detector at LEP, are presented. These results are interpreted in terms of constraints on the quark masses and on the b-quark kinetic energy value.Comment: Presented at the XXXI Conference on High Energy Physics Amsterdam, July 200

    Electronic/electric technology benefits study

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    The benefits and payoffs of advanced electronic/electric technologies were investigated for three types of aircraft. The technologies, evaluated in each of the three airplanes, included advanced flight controls, advanced secondary power, advanced avionic complements, new cockpit displays, and advanced air traffic control techniques. For the advanced flight controls, the near term considered relaxed static stability (RSS) with mechanical backup. The far term considered an advanced fly by wire system for a longitudinally unstable airplane. In the case of the secondary power systems, trades were made in two steps: in the near term, engine bleed was eliminated; in the far term bleed air, air plus hydraulics were eliminated. Using three commercial aircraft, in the 150, 350, and 700 passenger range, the technology value and pay-offs were quantified, with emphasis on the fiscal benefits. Weight reductions deriving from fuel saving and other system improvements were identified and the weight savings were cycled for their impact on TOGW (takeoff gross weight) and upon the performance of the airframes/engines. Maintenance, reliability, and logistic support were the other criteria

    The law of silent things

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    The failure to provide a ladder was quite silent in itself as to the issue ofcausation

    The effect of fluorine on viscosities in the system Na2O-Al2O3-SiO2: implications for phonolites, trachytes and rhyolites

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    The effect of fluorine on melt viscosities of five compositions in the system Na2O-Al2O3- SiO2h as been investigateda t one atmospherea nd 1000-1600'Cb y concentric-cylinder viscometry. The compositions chosen were albite, jadeite and nepheline on the join NaAlOlSiO2 and two others of the join at 75 mole percent SiO2, one peralkaline and one peraluminous. All melt viscosities were independent of shear rate over two orders of magnitude, indicating Newtonian behavior. All viscosity-temperature relationships were Arrhenian within error. Fluorine reduces the viscosities and activation energies of all melts investigated. The viscosity-reducing power of fluorine increases with the SiO2 content of melts on the join NaAlO2-SiO2 and is a maximum at Na/Al (molar) = I for melts containing 75 mole percent SiO2. Fluorine and water have similar effects on aluminosilicate melt viscosities, probably due to depolymerization of these melts by replacement of Si-O-(Si, Al) bridges with Si-OH and Si-F bonds, respectively. Evidence from slag systems shows that fluorine also reduces the viscosity of depolymerized silicate melts. The viscous flow of phonolites, trachytes and rhyolites will be strongly afected by fluorine. It appears that fluorine contents of igneous rocks may be combined with water in calculation schemes for determining the viscosity of natural melts

    My Own Pompeii

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    A comparison of teachers\u27 and parents\u27 perceptions of the behaviors of effective Catholic elementary school principals

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    This was a quantitative study investigating three main questions. The first two questions ascertained teachers\u27 and parents\u27 perceptions of the most important behaviors of effective Catholic elementary school principals in the areas of leadership styles, religious leader, instructional leader, administrator, and communicator, and the third question compared the perceptions of the two groups

    Flexibility vs consistency: Quantifying differences in neuromodulatory elicited patterns of activity

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    Central pattern generating circuits underly fundamental behaviors such as respiration or locomotion and are under the influence of neuromodulators. The presence of neuromodulators is thought to confer flexibility to these circuits to generate distinct patterns of activity to meet distinct behavioral needs. Network output flexibility can be achieved by distinct classes of neuromodulators, those which have convergent cellular actions but divergent circuit actions or by those which have divergent cellular actions but convergent circuit actions. Both classes of neuromodulator exist in the stomatogastric nervous system of the crab Cancer borealis and influence the activity of a central pattern generating circuit in the stomatogastric ganglion, the pyloric network. The ability of both classes of neuromodulator, when applied individually, to generate qualitatively and quantitatively distinct patterns of activity has been demonstrated with respect to a baseline activity state. While it is assumed that each individual neuromodulator’s activity pattern is distinct, there has yet to be a fully quantitative description of the degree of difference between two modulated activity patterns. It is also unlikely that any single circuit will be under the influence of only a single neuromodulator at any point. Therefore, the possibility of generating distinct network outputs increases with each distinct combination of neuromodulators. While the actions of individual neuromodulators have been explored, the consequences of co-modulation on the pyloric network’s output are less understood. Previous attempts at quantifying the effects of a neuromodulator on the pyloric network output relied on evaluating only a single, often multi-dimensional, attribute of activity at a time and statistically testing the dependent parameters of that attribute with statistics that assume independence. This dissertation uses a new approach to quantify and statistically test how different one neuromodulator elicited pattern of activity is from another, preserving the inherent multi-dimensional nature of the attributes evaluated. The results of this dissertation show that the pyloric network output is able to generate statistically distinct network outputs with individual neuromodulators; however, flexibility is lost in favor of consistency under co-modulatory conditions
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