Anisotropic Bianchi Type-II Massive String Cosmological Models with Time-Decaying Λ Term and Thermodynamic Parameters

Abstract

The present paper envisages a spatially homogeneous and anisotropic Bianchi II massive string cosmological models with time-decaying Λ term in general relativity. By using the variation law of Hubble's parameter, the Einstein's field equations have been solved for two general cases. The first case involving a power law solution describes the dynamics of universe from big bang to present epoch while the second case admit an exponential solution seems reasonable to project dynamics of future universe. We observed that massive strings dominate in early universe and eventually disappear at late time, which is consistent with the current astronomical observations. It has been found that the cosmological constant (Λ) is a decreasing function of time and it approaches to small positive value at sufficiently large time. The thermodynamic properties of anisotropic Bianchi II universe are studied and also the absolute temperature and entropy distribution are given explicitly. The relations between thermodynamic parameters and cosmological constant Λ has been established. Physical behavior of the derived model is elaborated in detail.

Thermal Stability and Starch Degradation Profile of α-Amylase fromStreptomyces avermitilis

“…Amylases from Streptomyces species have been reported and highlighted for the production of many products, 4) but most enzymes from Streptomyces sp. have weak thermal properties (thermostability and optimal temperature) compared to amylases from other hosts such as Bacillus and Aspergillus species, [5][6][7] and they usually show high activity at ambient temperature or below 40 C, except in a few cases. 8,9) Streptomyces avermitilis is known to produce many secondary metabolites, and its genome sequence has been determined.…”