Rocket flames

Among the important parameters which characterize the rocket flames are the (1) velocity, (2) pressure, (3) temperature of the exhaust gases and (4) the nature of chemical reactions in the flame of such gases. For the determination of these quantities ordinary methods fail because the flow of exhaust gases is supersonic in character. An introduction of a probe or any foreign body will create such strong disturbances in the supersonic flow that the readings of observing instruments will have no value. Spectroscopic methods are therefore eminently suitable because observations can be taken on the flame under running conditions

Radiating black hole solutions in Einstein-Gauss-Bonnet gravity

In this paper, we find some new exact solutions to the Einstein-Gauss-Bonnet equations. First, we prove a theorem which allows us to find a large family of solutions to the Einstein-Gauss-Bonnet gravity in $n$-dimensions. This family of solutions represents dynamic black holes and contains, as particular cases, not only the recently found Vaidya-Einstein-Gauss-Bonnet black hole, but also other physical solutions that we think are new, such as, the Gauss-Bonnet versions of the Bonnor-Vaidya(de Sitter/anti-de Sitter) solution, a global monopole and the Husain black holes. We also present a more general version of this theorem in which less restrictive conditions on the energy-momentum tensor are imposed. As an application of this theorem, we present the exact solution describing a black hole radiating a charged null fluid in a Born-Infeld nonlinear electrodynamics

A Note on trapped Surfaces in the Vaidya Solution

The Vaidya solution describes the gravitational collapse of a finite shell of incoherent radiation falling into flat spacetime and giving rise to a Schwarzschild black hole. There has been a question whether closed trapped surfaces can extend into the flat region (whereas closed outer trapped surfaces certainly can). For the special case of self-similar collapse we show that the answer is yes, if and only if the mass function rises fast enough.Comment: 14 pages, 4 figures; minor polish added to version

THE ROLE OF SIRAA VYADHANA IN TREATING BHASMAKA ROGA (ATYAGNI)

Acharya Charaka in Grahani Chikitsa Adhyaya explained about Siraa Vyadhana in the management of Atyagni. Atyagni can be considered as one of the serious conditions as it leads to severe weakness thereby patient may succumb to death also. Strength of the patient, nature and Seriousness of the disease should be considered before performing Siraa Vyadhana. Agni is a key factor in transformation of consumed Ahara Dravya of Vijatiya origin to Sajatiya nature with the help of Vata, converts the Ahara into Rasadi Dhatus and Malas. In this disorder mainly Vata and Agni plays major role. Because of this Anilaanalam the food is digested very quickly it leads to effect on Dhatwagni and Uttharothara Dhatu Prakriya. “Depletion of digestive fire†which is being developed after Siraa Vyadhana. Acharyas clearly explained about Raktha, Pitta and Agni relation in different concepts, if draw the Raktha from body directly it acts on Raktha Dhatu after that Rasa Dhatu, Dhatwagni Mandhya and Mandhata of Agni. So in Atyagni condition Siraa Vyadhana is one of the treatment modality. Intension of this paper is to highlight the concept and effect of Siraa Vyadhana in Atyagni (Bhasmaka Roga)

Relativistic Green functions in a plane wave gravitational background

We consider a massive relativistic particle in the background of a gravitational plane wave. The corresponding Green functions for both spinless and spin 1/2 cases, previously computed by A. Barducci and R. Giachetti \cite{Barducci3}, are reobtained here by alternative methods, as for example, the Fock-Schwinger proper-time method and the algebraic method. In analogy to the electromagnetic case, we show that for a gravitational plane wave background a semiclassical approach is also sufficient to provide the exact result, though the lagrangian involved is far from being a quadratic one.Comment: Last paper by Professor Arvind Narayan Vaidya, 18 pages, no figure