Brans-Dicke theory: Jordan vs Einstein Frame

It is well known that, in contrast to general relativity, there are two conformally related frames, the Jordan frame and the Einstein frame, in which the Brans-Dicke theory, a prototype of generic scalar-tensor theory, can be formulated. There is a long standing debate on the physical equivalence of the formulations in these two different frames. It is shown here that gravitational deflection of light to second order accuracy may observationally distinguish the two versions of the Brans-Dicke theory.Comment: 10 pages, Accepted by Mod. Phys. Letts.

Behaviour of the EAS Age Parameter in the Knee Energy Region

Analyzing simulated EAS events generated with the CORSIKA code, the characteristics of lateral distribution of electrons in EAS around the knee energy region of the primary energy spectrum have been studied and compared with experimental observations. The differences between the EGS4 and the NKG output of CORSIKA in respect to electron radial density distribution have been investigated. The relation between lateral and longitudinal age parameters has been studied after introducing the notion of the local age parameter that reflects the profile of the lateral distribution of electrons in EAS. The present analysis motivates the inclusion of the lateral shower age in a multiparameter study of EAS to extract information on hadronic interactions and primary composition.Comment: Talk presented at XVI International Symposium on Very High Energy Cosmic Ray Interactions (ISVHECRI 2010), Batavia, IL, USA (28 June - 2 July 2010). 4 pages, 5 figure

Effects of varying condensed distillers solubles, drying, and cooling temperatures on glass transition temperature of distillers dried grains

Distillers dried grains with solubles (DDGS), a coproduct of ethanol fuel production, is used as an animal feed and often must be transported long distances. DDGS flowability problems often create nuisance in storage and transportation. Materials above the glass transition temperature (Tg) can exist in a “rubbery state,”’ which is often responsible for particle agglomeration and caking. This study investigated the effects of varying condensed distillers solubles (CDS) (10, 15, and 20%, wb), drying (100, 200, and 300°C), and cooling temperature (–12 and 35°C) levels on the Tg of DDGS. Tg ranged from 34 to 58°C and 41 to 59°C for cooling temperatures of –12°C and 35°C, respectively. Tg data were used to develop an overall regression model, which yielded a predictive model with R² of 0.74 and SEM of 3.16. Using this model, optimum drying and cooling temperatures were determined. These conditions may be used to reduce flow problems

Testing gravity at the Second post-Newtonian level through gravitational deflection of massive particles

Expression for second post-Newtonian level gravitational deflection angle of massive particles is obtained in a model independent framework. Several of its important implications including the possibility of testing gravitational theories at that level are discussed.Comment: 5 pages, couple of equations of the previous version are correcte

Strong field gravitational lensing in scalar tensor theories

Strong field gravitational lensing in the Brans-Dicke theory has been studied. The deflection angle for photons passing very close to the photon sphere is estimated for the static spherically symmetric space-time of the theory and the position and magnification of the relativistic images are obtained. Modeling the super massive central object of the galaxy by the Brans-Dicke space-time, numerical values of different strong lensing observable are estimated. It is found that against the expectation there is no significant scalar field effect in the strong field observable lensing parameters. This observation raises question on the potentiality of the strong field lensing to discriminate different gravitational theories.Comment: 20 pages, accepted in Class. Quantum Grav., final versio