Influences of Dark Energy and dark matter on Gravitational Time Advancement

The effect of dark matter/energy on gravitational time advancement (negative effective time delay) has been investigated considering few dark energy/matter models including cosmological constant. It is found that dark energy gives only (positive) gravitational time delay irrespective of the position of the observer whereas pure Schwarzschild geometry leads to gravitational time advancement when the observer is situated at relatively stronger gravitational field point in the light trajectory. Consequently, there will be no time advancement effect at all at radial distances where gravitational field due to dark energy is stronger than the gravitational field of Schwarzschild geometry.Comment: 7 pages, no figur

Effects of dark energy and flat rotation curve on the gravitational time delay of particle with non-zero mass

The effects of several dark energy models on gravitational time delay of particles with non-zero mass are investigated and analytical expressions for the same are obtained at the first order accuracy. Also the expression for gravitational time delay under the influence of conformal gravity potential that well describes the flat rotation curve of spiral galaxies is derived. The findings suggest that i) the conformal gravity description of dark matter reduces the net time delay in contrast to the effect of normal dark matter and therefore in principle the models can be discriminated using gravitational time delay observations and ii)the effect of dark energy/flat rotation curve may be revealed from high precision measurements of gravitational time delay of particles involving megaparsec and beyond distance-scale.Comment: 10 page

Effect of edible coatings for enhancing shelf-life and quality in Ber (Zizyphus mauritiana Lamk.) fruits

An experiment was conducted to study the effect of post-harvest application of different edible coatings like Chitosan (0.5%, 1.0%, 2.0%), Guar gum (1%, 1.5%, 2%), Gum tragacanth (1.0%, 1.5%, 2.0%) on shelf life and quality of cv. BAU ber. Fruits of uniform size were harvested at physiological maturity and treated with various edible coatings. Observations were recorded at intervals of 4 days from storage on physiological loss in weight, fruit length, breadth, colour, TSS, total sugar, reducing sugar,acidity, and ascorbic acid. The results revealed that coating of fruits resulted in reduced loss in fruit weight and higher level of ascorbic acid content, TSS, acidity, total sugar, reducing sugar as compared to the fruits under control. The most effective coating was Guar gum (2%) that extended the shelf life of ber up to 16 days. Fruits under control had a shelf life of only10 days

Test of conformal theory of gravity as an alternative paradigm to dark matter hypothesis from gravitational lensing studies

Weyl's conformal gravity theory, which is considered as a compelling alternative to general relativity theory, has been claimed to describe the observed flat rotation curve feature of spiral galaxies without the need of invoking dark matter. However, it is important to examine whether the Weyl theory can also explain the relevant gravitational lensing observations correctly without considering any dark matter. In this regard, the gravitational bending angle in static spherically space-time (Mannheim-Kazanas metric) in Weyl theory has been calculated by several authors over the last two decades, but the results are found largely divergent. In this work, we have revisited the problem and obtain the correct and consistent expression of the deflection angle in conformal gravity. Subsequently we perform the gravitational lensing analysis. We compare the prediction of Weyl gravity with the gravitational lensing observations of the rich galaxy clusters Abell 370 and Abell 2390 and is found that Weyl theory cannot describe the stated lensing observations without considering dark matter.Comment: 9 page