17,358 research outputs found

    Trade-Mark Licensing—A Saga of Fantasy and Fact

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    Legal Aspects of Architecture, Engineering and the Construction Process by Justin Sweet

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    Syftet med detta examensarbete Àr att ta reda pÄ vilken kunskap lÀrare har om undervisning i lÀsförstÄelse, hur lÀrare pÄ lÄgstadiet beskriver sin undervisning men Àven hur lÀsundervisningen förÀndras efter att eleven knÀckt lÀskoden och kommit igÄng med sin lÀsning. Det empiriska materialet bestÄr av insamlad data genom intervjuer med sex lÄgstadielÀrare. Studien Àr kvalitativ med en fenomenografisk metodansats men Àven inspirerad av fenomenolgin. Resultaten visar att lÀrarna har svÄrt att definiera och beskriva vad lÀsförstÄelse Àr. I lÀrarnas  yrkessprÄk saknas mÄnga ord och begrepp för att tala om lÀsning och lÀsförstÄelse . Att döma av hur lÀrarna beskriver sin undervisning har de ingen tydlig struktur för arbetet med lÀsförstÄelse, Àven om de nÀmner ett antal olika arbetssÀtt, och det tycks inte finnas nÄgon vÀl genomtÀnkt progression för elevens lÀsförstÄelseutveckling. NivÄanpassade lÀromedel och individualisering Àr det sÀtt som vanligtvis anvÀnds nÀr undervisningen ska anpassas efter elevens utveckling i lÀsförstÄelse. Studien visar ocksÄ att det behövs mera fortbildning för lÀrarna i vad lÀsning och lÀsförstÄelse Àr. Goda kunskaper om lÀsprocessen och lÀsförstÄelse Àr en förutsÀttning för att nÄ goda resultat i lÀsundervisningen

    Pick matrix conditions for sign-definite solutions of the algebraic Riccati equation

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    We study the existence of positive and negative semidefinite solutions of algebraic Riccati equations (ARE) corresponding to linear quadratic problems with an indefinite cost functional. The problem to formulate reasonable necessary and sufficient conditions for the existence of such solutions is a long-standing open problem. A central role is played by certain two-variable polynomial matrices associated with the ARE. Our main result characterizes all unmixed solutions of the ARE in terms of the Pick matrices associated with these two-variable polynomial matrices. As a corollary of this result we obtain that the signatures of the extremal solutions of the ARE are determined by the signatures of particular Pick matrices

    Investigation of Cathode Kinetics in SOFC: Model Thin Film SrTi_(1-x)Fe_xO_(3-ÎŽ) Mixed Conducting Oxides

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    To understand the kinetics controlling the SOFC cathode processes, a model mixed conducting perovskite materials system, SrTi_(1-x)Fe_xO_(3-ÎŽ), was selected, offering the ability to systematically control both the levels of electronic and ionic electrical conductivity as well as the energy band structure. This, in combination with considerably simplified electrode geometry, served to demonstrate that the rate of oxygen exchange at the surface of SrTi_(1-x)Fe_xO_(3-ÎŽ) is only weakly correlated with either high electronic or ionic conductivity, in apparent contradiction with common expectations. On the other hand, evidence was found suggesting the importance of minority electronic species in determining the rate of oxygen exchange. Furthermore, the enrichment of Sr to the surface of the electrodes was found to reduce the oxygen exchange rate constant; this effect becoming more evident with increasing values of x. The observed trends are discussed in relation to the cathodic behavior of MIEC electrodes

    The Perturbative Resummed Series for Top Production

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    Our calculation of the total cross section for inclusive production of ttˉt\bar{t} pairs in hadron collisions is summarized. The principal ingredient of this calculation is resummation of the universal leading-logarithm effects of gluon radiation to all orders in the quantum chromodynamics coupling strength, restricted to the region of phase space that is manifestly perturbative. We present predictions of the physical cross section as a function of top quark mass in proton-antiproton reactions at center-of-mass energies of 1.8 and 2.0 TeV.Comment: 9 pages. Latex file plus 6 ps files of figures submitted togther in uuencoded form; invited talk presented by Harry Contopanagos at the XXXI Rencontres de Moriond on QCD and High Energy Hadronic Interactions, Les Arcs, France, March, 1996. New version to correct problem with unsuccessful posting of figures on May

    Threshold Resummation and the Total Cross Section for Top Quark Production

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    We discuss the motivation for resummation of the effects of initial-state soft-gluon radiation, to all orders in the strong coupling strength, for processes in which the near-threshold region in the partonic subenergy is important. We summarize our calculation of the total cross section for top quark production at hadron colliders. Comments are included on the differences between our treatment of subleading logarithmic terms and other methods.Comment: 7 pages, 1 figure, uses aipproc.sty; Paper presented by E. L. Berger, to be published in the Proceedings of DIS'97, Fifth International Workshop on Deep Inelastic Scattering and QCD, Chicago, IL, April 14 - 18, 199

    Hamiltonian and Variational Linear Distributed Systems

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    We use the formalism of bilinear- and quadratic differential forms in order to study Hamiltonian and variational linear distributed systems. It was shown in [1] that a system described by ordinary linear constant-coefficient differential equations is Hamiltonian if and only if it is variational. In this paper we extend this result to systems described by linear, constant-coefficient partial differential equations. It is shown that any variational system is Hamiltonian, and that any scalar Hamiltonian system is contained (in general, properly) in a particular variational system

    High-flaps for natural laminar flow airfoils

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    A review of the NACA and NASA low-drag airfoil research is presented with particular emphasis given to the development of mechanical high-lift flap systems and their application to general aviation aircraft. These flap systems include split, plain, single-slotted, and double-slotted trailing-edge flaps plus slat and Krueger leading-edge devices. The recently developed continuous variable-camber high-lift mechanism is also described. The state-of-the-art of theoretical methods for the design and analysis of multi-component airfoils in two-dimensional subsonic flow is discussed, and a detailed description of the Langley MCARF (Multi-Component Airfoil Analysis Program) computer code is presented. The results of a recent effort to design a single- and double-slotted flap system for the NASA high speed natural laminar flow (HSNLF) (1)-0213 airfoil using the MCARF code are presented to demonstrate the capabilities and limitations of the code
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