17,731 research outputs found
Legal Aspects of Architecture, Engineering and the Construction Process by Justin Sweet
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
The behavioral approach to systems and modeling
An introduction to behavioral system theory, and a brief review of the content of the Special Issue are given
Pick matrix conditions for sign-definite solutions of the algebraic Riccati equation
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
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
Our calculation of the total cross section for inclusive production of
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
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
Top Quark Production Dynamics in QCD
A calculation of the total cross section for top quark production in
hadron-hadron collisions is presented based on an all-orders perturbative
resummation of initial-state gluon radiative contributions to the basic quantum
chromodynamics subprocesses. Principal-value resummation is used to evaluate
all relevant large threshold contributions. In this method there are no
arbitrary infrared cutoffs, and the perturbative regime of applicability is
well defined, two attributes that significantly reduce the estimated
uncertainty of the results. For collisions at center-of-mass energy
TeV and a top mass of 175 GeV, we obtain
, in agreement with experiment.
Predicted cross sections are provided as a function of top mass in
collisions at TeV and in collisions at CERN LHC energies.Comment: 12 pages. Latex file plus 8 ps files of figures submitted altogther
in uuencoded form; Invited talk presented by E. L. Berger at the
International Symposium on Heavy Flavor and Electroweak Theory, Beijing,
August 16 - 19, 199
High-flaps for natural laminar flow airfoils
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
- âŠ