Analytical solution of two-layer beam taking into account interlayer slip and shear deformation

A mathematical model is proposed and its analytical solution derived for the analysis of the geometrically and materially linear two-layer beams with different material and geometric characteristics of an individual layer. The model takes into account the effect of the transverse shear deformation on displacements in each layer. The analytical study is carried out to evaluate the influence of the transverse shear deformation on the static and kinematic quantities. We study a simply supported two-layer planar beam subjected to the uniformly distributed load. Parametric studies have been performed to investigate the influence of shear by varying material and geometric parameters, such as interlayer slip modulus (K), flexural-to-shear moduli ratios (E/G) and span-to-depth ratios (L/h). The comparison of the results for vertical deflections shows that shear deformations are more important for high slip modulus, for ``short'' beams with small L/h ratios, and beams with high E/G ratios. In these cases, the effect of the shear deformations becomes significant and has to be addressed in design. It also becomes apparent that models, which consider the partial interaction between the layers, should be employed if beams have very flexible connections

Patterns in Olmec monument mutilation at La Venta and San Lorenzo

Thesis (B.A.) in Liberal Arts and Sciences -- University of Illinois at Urbana-Champaign, 1988.Bibliography: leaves 34-35.Microfiche of typescript. [Urbana, Ill.]: Photographic Services, University of Illinois, U of I Library, [1988]. 2 microfiches (42 frames): negative

Marginal deformations in string field theory

We describe a method for obtaining analytic solutions corresponding to exact marginal deformations in open bosonic string field theory. For the photon marginal deformation we have an explicit analytic solution to all orders. Our construction is based on a pure gauge solution where the gauge field is not in the Hilbert space. We show that the solution itself is nevertheless perfectly regular. We study its gauge transformations and calculate some coefficients explicitly. Finally, we discuss how our method can be implemented for other marginal deformations.Comment: 23 pages. v2: Some paragraphs improved, typos corrected, ref adde

Boundary State from Ellwood Invariants

Boundary states are given by appropriate linear combinations of Ishibashi states. Starting from any OSFT solution and assuming Ellwood conjecture we show that every coefficient of such a linear combination is given by an Ellwood invariant, computed in a slightly modified theory where it does not trivially vanish by the on-shell condition. Unlike the previous construction of Kiermaier, Okawa and Zwiebach, ours is linear in the string field, it is manifestly gauge invariant and it is also suitable for solutions known only numerically. The correct boundary state is readily reproduced in the case of known analytic solutions and, as an example, we compute the energy momentum tensor of the rolling tachyon from the generalized invariants of the corresponding solution. We also compute the energy density profile of Siegel-gauge multiple lump solutions and show that, as the level increases, it correctly approaches a sum of delta functions. This provides a gauge invariant way of computing the separations between the lower dimensional D-branes.Comment: v2: 63 pages, 14 figures. Major improvements in section 2. Version published in JHE

Level truncation analysis of exact solutions in open string field theory

We evaluate vacuum energy density of Schnabl's solution using the level truncation calculation and the total action including interaction terms. The level truncated solution provides vacuum energy density expected both for tachyon vacuum and trivial pure gauge. We discuss the role of the phantom term to reproduce correct vacuum energy.Comment: 11 pages, 6 figures,v2: 1 figure replace

On the validity of the solution of string field theory

We analyze the realm of validity of the recently found tachyon solution of cubic string field theory. We find that the equation of motion holds in a non trivial way when this solution is contracted with itself. This calculation is needed to conclude the proof of Sen's first conjecture. We also find that the equation of motion holds when the tachyon or gauge solutions are contracted among themselves.Comment: JHEP style, 9+1 pages. Typos correcte

Solitons on compact and noncompact spaces in large noncommutativity

We study solutions at the minima of scalar field potentials for Moyal spaces and torii in the large non-commutativity and interprete these solitons in terms of non-BPS D-branes of string theory. We derive a mass spectrum formula linking different D-branes together on quantum torii and suggest that it describes general systems of D-brane bound states extending the D2-D0 one. Then we propose a shape for the effective potential approaching these quasi-stable bound states. We give the gauge symmetries of these systems of branes and show that they depend on the quantum torii representations.Comment: 25 pages, Latex, 1 figure (use epsfig.sty), corrected formul

Mindestkurs für den Schweizer Franken: Gefährlicher Interventionismus der SNB?

Die Schweiz ist in den vergangenen Monaten durch die drastische Aufwertung des Schweizer Franken gegenüber dem Euro unter Druck geraten. Im September 2011 verkündete deshalb die Schweizerische Nationalbank (SNB) einen Mindestkurs des Franken zum Euro. Mit einer Untergrenze von 1,20 Franken je Euro soll der nach Ansicht der SNB »massiven Überbewertung« der Währung entgegengewirkt werden. Oliver Landmann, Universität Freiburg, sieht diese Maßnahme vor dem Hintergrund, dass die Schweiz als kleine offene Volkswirtschaft auch als Nicht-Mitglied der Europäischen Union aufs Engste mit ihrem politischen und wirtschaftlichen Umland verbunden ist. Das bedeutet, dass das Land von allen positiven wie negativen Entwicklungen in der EU betroffen sein wird. Deshalb wäre es eine Illusion zu glauben, die Schwierigkeiten, in welche die Eurozone durch ihre aktuelle Krise geraten ist, könnten an der Schweiz vorbeigehen. Die Festlegung eines Mindestkurses von 1,20 Fr. ist zwar kein Wundermittel, aber eine »mit Bedacht ergriffene Maßnahme der Schadensminimierung«. Gunther Schnabl, Universität Leipzig, betont, dass die Schweiz mit dieser Entscheidung geldpolitischen Handlungsspielraum zurückgewinnt, da sie sich »von dem Fluch spekulativer Kapitalzuflüsse« teilweise befreien kann. Allerdings bleibe die Wechselkursbindung im derzeitigen Umfeld der globalen Liquiditätsschwemme sowie instabiler europäischer Staatshaushalte und Banken nur eine unbefriedigende Lösung. Denn bei festem Wechselkurs und steigender Inflation werden die immensen Euro-Reserven in der Schweizerischen Zentralbankbilanz langfristig real entwertet. Damit werde die Sozialisierung der Kosten der europäischen Staatsschulden- und Finanzkrisen auf die Schweiz ausgeweitet. David Iselin und Michael J. Lamla, KOF Konjunkturforschungsstelle der ETH Zürich, werten die Einführung der Wechselkursuntergrenze als Erfolg und das Risiko dieses Engagements der SNB als gering. Angesichts der erwarteten niedrigen Inflationsraten im nächstenSchweizer Franken, Wechselkurs, Wechselkurspolitik, Finanzmarktkrise, Eurozone, Interventionismus, Zentralbank, Schweiz

Wedge states in string field theory

The wedge states form an important subalgebra in the string field theory. We review and further investigate their various properties. We find in particular a novel expression for the wedge states, which allows to understand their star products purely algebraically. The method allows also for treating the matter and ghost sectors separately. It turns out, that wedge states with different matter and ghost parts violate the associativity of the algebra. We introduce and study also wedge states with insertions of local operators and show how they are useful for obtaining exact results about convergence of level truncation calculations. These results help to clarify the issue of anomalies related to the identity and some exterior derivations in the string field algebra.Comment: 40 pages, 9 figures, v3: section 3.3 rewritten, few other corrections, set in JHEP styl