Effective of Passive Devices in Alleviation of Flow-induced oscillations of he nozzles of a Multi-Booster Launch vehicle

Wind tunnel tests to quantify the flow induced oscillations of nozzles of strap-on boosters of a typical launch vehicle have been performed under jet-off conditions in the Mach number range 0.8 to 2.5. The effects of gymballing the nozzles on the steady and unsteady radial and tangential moments acting at the simulated position of gymbal actuators have been studied. The loads are seen to increase as the gymbal angle increases. The effectiveness of various load alleviating passive devices in reducing steady and unsteady loads was evaluated. The most effective device was found to be a semi-circular segment. The spectra of unsteady moments indicate that the loads alleviating devices do not significantly alter the magnitude as compared to that of the baseline data

Gravitational Couplings, Orientifolds and M-Planes

We examine string-theory orientifold planes of various types including the Sp and SO-odd planes, and deduce the gravitational Chern-Simons couplings on their world-volumes. Consistency checks are carried out in different spacetime dimensions using various dualities, including those relating string theory with F-theory and M-theory. It is shown that when an orientifold 3-plane crosses a 5-brane, the jump in the charge is accompanied by a corresponding change in the gravitational couplings.Comment: 14 pages, harvmac (b), 2 figures, referencing improved and a reference added, no changes in conten

Gauge-Invariant Couplings of Noncommutative Branes to Ramond-Ramond Backgrounds

We derive the couplings of noncommutative D-branes to spatially varying Ramond-Ramond fields, extending our earlier results in hep-th/0009101. These couplings are expressed in terms of *n products of operators involving open Wilson lines. Equivalence of the noncommutative to the commutative couplings implies interesting identities as well as an expression for the Seiberg-Witten map that was previously conjectured. We generalise our couplings to include transverse scalars, thereby obtaining a Seiberg-Witten map relating commutative and noncommutative descriptions of these scalars. RR couplings for unstable non-BPS branes are also proposed.Comment: harvmac, 22 pages, v2: typos corrected, references and acknowledgements adde

Holographic chiral induced W-gravities

We study boundary conditions for 3-dimensional higher spin gravity that admit asymptotic symmetry algebras expected of 2-dimensional induced higher spin theories in the light cone gauge. For the higher spin theory based on sl(3, R) plus sl(3,R) algebra, our boundary conditions give rise to one copy of classical W3 and a copy of sl(3,R) or su(1,2) Kac-Moody symmetry algebra. We propose that the higher spin theories with these boundary conditions describe appropriate chiral induced W-gravity theories on the boundary. We also consider boundary conditions of spin-3 higher spin gravity that admit u(1) plus u(1) current algebra.Comment: 19 page

On Asymptotic Symmetries of 3d Extended Supergravities

We study asymptotic symmetry algebras for classes of three dimensional supergravities with and without cosmological constant. In the first part we generalise some of the non-Dirichlet boundary conditions of $AdS_3$ gravity to extended supergravity theories, and compute their asymptotic symmetries. In particular, we show that the boundary conditions proposed to holographically describe the chiral induced gravity and Liouville gravity do admit extension to the supergravity contexts with appropriate superalgebras as their asymptotic symmetry algebras. In the second part we consider generalisation of the 3d $BMS$ computation to extended supergravities without cosmological constant, and show that their asymptotic symmetry algebras provide examples of nonlinear extended superalgebras containing the $BMS_3$ algebra

A little more Gauge Mediation and the light Higgs mass

We consider minimal models of gauge mediated supersymmetry breaking with an extra $U(1)$ factor in addition to the Standard Model gauge group. A $U(1)$ charged, Standard Model singlet is assumed to be present which allows for an additional NMSSM like coupling, $\lambda H_u H_d S$. The U(1) is assumed to be flavour universal. Anomaly cancellation in the MSSM sector requires additional coloured degrees of freedom. The $S$ field can get a large vacuum expectation value along with consistent electroweak symmetry breaking. It is shown that the lightest CP even Higgs boson can attain mass of the order of 125 GeV.Comment: 29 pages, 7 Figures; v2: updated references 30 pages, minor wordings modified, to appear in Nucl. Phys.