Stability analysis for cosmological models in f(R)f(R) gravity using dynamical system analysis

Modified gravity theories have received increased attention lately to understand the late time acceleration of the universe. This viewpoint essentially modifies the geometric components of the universe. Among numerous extension to Einstein's theory of gravity, theories which include higher order curvature invariant, and specifically the class of $f(R)$ theories, have received several acknowledgments. In our current work we try to understand the late time acceleration of the universe by modifying the geometry of the space and using dynamical system analysis. The use of this technique allows to understand the behavior of the universe under several circumstances. Apart from that we study the stability properties of the critical point and acceleration phase of the universe which could then be analyzed with observational data. We consider a particular model $f(R) = R - \mu R_{c}(R/R_{c})^{p}$ with $0 < p < 1, \mu, R_{c} > 0$ for the study. As a first case we consider the matter and radiation component of the universe with an assumption of no interaction between them. Later, as a second case we take matter, radiation and dark energy (cosmological constant) where study on effects of linear, non-linear and no interaction between matter and dark energy is considered and results have been discussed in detail.Comment: 16 pages and 10 figures, published in EPJ

Analyzing the effectiveness of a Dairy Cooperative/The cost of Milk Production

Agricultural cooperatives have been a unique way of addressing the concerns of the producers and consumers regarding pricing, storage, marketing, and other such activities of bringing the commodity to the market. One of such sectors is the dairy, where there are cooperatives in both the developed and developing countries. Amul Dairy, a milk cooperative in India is, synonymous with quality of its milk and milk products as well as fair prices to both the consumer and producer. In this paper, we examine the effectiveness of Amul by comparing the procurement prices offered by the dairy cooperative to the cost of producing milk. We must caution about the conclusions that we draw from this project as the study is conducted in only one village out of the many where Amul operates

Exploring the Cost of Milk Production & Potential Economies of Scale in a Dairy Cooperative

Agricultural cooperatives have been a unique way of addressing the concerns of the producers and consumers regarding pricing, storage, marketing, and other such activities of bringing the commodity to the market. One of such sectors is the dairy, where there are cooperatives in both the developed and developing countries. Amul Dairy, a milk cooperative in India is, synonymous with quality of its milk and milk products as well as fair prices to both the consumer and producer. In this study, we will examine the effectiveness of Amul by comparing the procurement prices offered by the dairy cooperative to the cost of producing milk. In addition, we will measure whether there are economies of scale in milk production

Qualitative behavior of cosmological models combining various matter fields

The late time accelerated expansion of the universe can be realized using scalar fields with given self-interacting potentials. Here we consider a straightforward approach where a three cosmic fluid mixture is assumed. The fluids are standard matter perfect fluid, dark matter, and a scalar field with the role of dark energy. A dynamical system analysis is developed in this context. A central role is played by the equation of state $\omega_{eff}$ which determines the acceleration phase of the models. Determining the domination of a particular fluid at certain stages of the universe history by stability analysis allows, in principle, to establish the succession of the various cosmological eras.Comment: 18 pages, 7 figures, accepted in IJMP

Ultrafast infrared spectroscopy of nitrous oxide as a probe in salt water and supercritical sulfur hexafluoride

Different forms of ultrafast spectroscopy, namely two-dimensional infrared spectroscopy (2DIR) and pump probe spectroscopy, are used to determine spectral diffusion, vibrational energy relaxation (VER), and the dynamics of the solvent environments around probe molecules in various solutions. Supercritical fluids are valuable as potential green solvents, so it is important to explore and understand these dynamical processes in these solvents. Ultrafast pump-probe spectroscopy was used to investigate the VER of nitrous oxide (N2O) dissolved in water with different concentrations of ionic salts. Chloride salts of different cations were used to determine changes in VER and reorientation anisotropy decay (R(t)) of N2O as a function of cation. These rates were found to be consistent with the Hoffmeister series trend of structure makers and structure breakers and showed evidence of cation effects on the water hydrogen bonding network beyond the first solvation shell. Ultrafast two-dimensional infrared (2DIR) spectroscopy of N2O’s asymmetric stretching (√3) mode in sulfur hexafluoride (SF6) gas resulted in rovibrational spectral lineshapes which show complicated behavior compared to 2DIR lineshapes of traditional condensed phase samples. There is an additional antidiagonal features which appears in the spectra of dense state points. These observed spectra indicate that there is a quasi-free rotor population, which is captured by a model including all 36 possible rovibrational density matrix pathways originating from a specific J-level. The decays of these 2DIR spectral features can be attributed to the N2O and SF6 collisions, roughly decaying on the scale of one to two collisions. Further 2DIR spectra were taken of the system in the supercritical regime of SF6. Even at these supercritical state points, the frequency correlation decay is still on the order of one to two collisions and confirm that an independent binary collision model is sufficient for describing rotational relaxation in these SCF solutions. Pump-probe spectroscopic measurements offer N2O √3 vibrational relaxation timescales ~10 times slower than spectral diffusion dynamics attributable to rotational relaxation. The growth of a “Q”-type 1 ← 0 √3 transition feature in the null region of the mid-IR spectrum is observed with increasing fluid density. Analysis based on these 2DIR results indicates this feature is a sign of liquid-like character in these solutions and that both hindered and quasi-free rotors exist in the same solvent environment in the dense and supercritical N2O – SF6 solution. This experimental methodology enables future lineshape studies on the effects of solvent interactions on vibrational and rotational relaxation rates, dynamics from non-equilibrium states at high temperature and pressures, and critical point solvation dynamics

Internet of things-blockchain lightweight cryptography to data security and integrity for intelligent application

The industrial internet of things (IoT) plays a major role in the growth of automation and increasing digital connectivity for machine-to-machine communication. The research community has extensively investigated the possibility of IoT and blockchain integration for the last couple of years. The major research is focused on the benefits of integrating blockchain with IoT. In this work, we first focus on the issue of integrating IoT nodes with blockchain networks, especially for non-real-time IoT nodes that do not have an in-built clock mechanism. As a result, they cannot establish communication with real-time blockchain networks. Another critical security issue is protecting data coming from IoT devices to blockchain networks. Blockchain is enough mature to protect the data in its ecosystem. However, information coming from outside of the world does not have any guarantee of data integrity and security. This paper first addresses the clock synchronization issue of IoT nodes with blockchain using a network time protocol and then proposes an IoT-blockchain light-weight cryptographic (IBLWC) approach to secure the entire IoT-blockchain ecosystem. This paper also presents the performance analysis of IBLWC as a suitable and cost-effective solution that incurs less processing overhead for IoT-blockchain-based applications