This paper introduces a semi-empirical model to predict the downwash gradient at horizontal tail of three-lifting-surface aircraft. The superposition principle applied well established formulations valid for two lifting surfaces is not reasonable approach calculate canard-wing-tail layout, and this demonstrates that such basic technique leads incorrect results. Therefore, an ad hoc prediction p...

Using the monodromy method we calculate the asymptotic quasinormal (QN) frequencies of an electromagnetic field moving in D-dimensional Schwarzschild and Schwarzschild de Sitter (SdS) black holes (D ≥ 4). For theD-dimensional Schwarzschild anti-de Sitter (SadS) black hole we also compute these frequencies with a similar method. Moreover, we calculate the electromagnetic normal modes of the D-di...

We study the dynamical behavior of the dilaton in the background of three-dimensional Kerr-de Sitter space which is inspired from the low-energy string effective action. The perturbation analysis around the cosmological horizon of Kerr-de Sitter space reveals a mixing between the dilaton and other fields. Introducing a gauge (dilaton gauge), we can disentangle this mixing completely and obtain ...

Two ways in which de Sitter space can arise in supergravity theories are discussed. In the first, it arises as a solution of a conventional supergravity, in which case it necessarily has no Killing spinors. For example, de Sitter space can arise as a solution of N = 8 gauged supergravities in four or five dimensions. These lift to solutions of 11-dimensional supergravity or D = 10 IIB supergrav...

In this paper we discuss the question of whether the entropy of cosmological horizon in some asymptotically de Sitter spaces can be described by the Cardy-Verlinde formula, which is supposed to be an entropy formula of conformal field theory in any dimension. For the Schwarzschild-de Sitter solution, although the gravitational mass is always negative (in the sense of the prescription in hep-th/...

Semiclassical gravity predicts that de Sitter space has a finite entropy. We suggest a picture for Euclidean de Sitter space in string theory, and use the AdS/CFT correspondence to argue that de Sitter entropy can be understood as the number of degrees of freedom in a quantum mechanical dual.

A relation between the Friedmann equation and the Cardy formula has been found for de Sitter closed and Anti de Sitter flat universes. For the remaining (Anti) de Sitter universes the arguments fail, and we speculate whether the general philosophy of holography can be satisfied in such contents. PACS number(s): 04.70.Dy, 98.80.Cq e-mail:[email protected] e-mail:[email protected] e-mail...

From the partition function of canonical ensemble we derive the entropy of the de Sitter space by anti-Wick rotation. And then from the one-loop bubble S 2 × S 2 created from vacuum fluctuation in de Sitter background space, we obtain the one-loop quantum correction to the entropy of de Sitter space.

Guidance and control of aircraft in the landing phase imposes extra pilot work loads, hence application of automatic landing control systems is of great importance. In this study automatic landing control systems are introduced and an optimal landing control system is designed. The control system performance criteria are based on minimum control effort. The designed system is simulated for a tr...

The present methodological study aims to assess boundary layer ingestion (BLI) as a promising method improve propulsion efficiency. BLI utilizes the low momentum inflow of wing or fuselage for thrust generation in order minimize required propulsive power given amount fuselage-embedded engines. A multi-segment parallel compressor model (PCM) is developed calculate saving from full annular occurr...