Warm inflation in <Emphasis Type="Italic">f</Emphasis>(<Emphasis Type="Italic">G</Emphasis>) theory of gravity

The aim of this paper is to explore warm inflation in the background of f(G) theory of gravity using scalar fields for the FRW universe model. We construct the field equations under slow-roll approximations and evaluate the slow-roll parameters, scalar and tensor power spectra and their corresponding spectral indices using viable power-law model. These parameters are evaluated for a constant as well as variable dissipation factor during intermediate and logamediate inflationary epochs. We also find the number of e-folds and tensor- scalar ratio for each case. The graphical behavior of these parameters proves that the isotropic model in f(G) gravity is compatible with observational Planck data.     

Chiral separation of three agrochemical toxins enantiomers by high-performance liquid chromatography on a vancomycin crystalline degradation products-chiral stationary phase

This work aims to evaluate for the enantiomeric separations of three agrochemical toxins: haloxyfop-methyl, fenoxaprop-p-ethyl and indoxacarb on crystalline degradation products-chiral stationary phase (CDP-CSP) of high-performance liquid chromatography (HPLC) under normal and polar organic phases. In the normal phase, the mobile phase was n-hexane with alcohols including methanol and isopropanol as polar modifiers. In the polar organic phase mode, the mobile phase was methanol with different percentages of triethylammunium acetate. The influence of flow rate (0.3-0.9 mL/min), analyte concentration and silica gel particle sizes (10, 15 and 30 microm) was investigated. This new chiral stationary phase showed excellent stereoselectivity for the two enantiomers of haloxyfop-methyl and fenoxaprop-p-ethyl and chiral recognition for indoxacarb under normal-phase mode. However, under polar organic phase, only indoxacarb was separated (alpha < 1.5). The chromatographic results were compared with commercial chiral columns.     

Neutral Particle Motion around a Schwarzschild Black Hole in Modified Gravity

We investigate circular motion of neutral test particles on equatorial plane near a black hole in scalar-tensor-vector gravity. We consider three cases (i) α < G/G_N (ii) α = G/G_N and (iii) α > G/G_N to find the regions where motion can exist. The corresponding effective potential, energy, angular momentum and center of mass energy are evaluated. Further, we define four different cases for α > G/G_N and identify stable and unstable regions of circular orbits. It is found that circular orbits having zero angular momentum exist at r = αGNM due to repulsive gravity effects. We conclude that the structure of stable regions for α < G/G_N as well as α = G/G_N case is completely different from that of α > G/G_N.     

Cosmological analysis of reconstructed $${\mathcal {F}}(T,T_{\mathcal {G}})$$ models

In this paper, we analyze cosmological consequences of the reconstructed generalized ghost pilgrim dark energy \({\mathcal {F}}(T,T_{\mathcal {G}})\) models in terms of redshift parameter z. For this purpose, we consider power-law scale factor, scale factor for two unified phases and intermediate scale factor. We discuss graphical behavior of the reconstructed models and examine their stability analysis. Also, we explore the behavior of equation of state as well as deceleration parameters and \(\omega _{\Lambda }-\omega _{\Lambda }^{'}\) as well as \(r-s\) planes. It is found that all models are stable for pilgrim dark energy parameter 2. The equation of state parameter satisfies the necessary condition for pilgrim dark energy phenomenon for all scale factors. All other cosmological parameters show great consistency with the current behavior of the universe.     

Viscosity Effects on Anisotropic Universe in Curvature-Matter Coupling Gravity

In this paper, we study evolution of the universe in the background of f(R, T) gravity using LRS Bianchi type-Ⅰ model. We discuss scale factors as well as deceleration parameter in dark energy dominated era for different bulk viscosity models. The occurrence of big-rip singularity is also examined. It is concluded that expansion is faster when bulk viscosity is proportional to Hubble parameter as compared to other models.     

One-pot conversion of carbamates of unsaturated β-aminoesters into unsaturated β-lactams by use of trimethylsilyl iodide

Trimethylsilyl iodide (TMSI) is introduced as an efficient reagent for the one-pot and direct transformation of carbamates of unsaturated β-aminoesters into the corresponding α-methylene-β-lactams and α-arylidene-β-lactams. The mild reaction conditions, excellent yields and easy work-up procedures make it a useful alternative to previously applied procedures for the rapid synthesis of β-lactams from easily available Baylis-Hillman adducts.     

Pilgrim dark energy in f(T) gravity

We discuss the interacting f(T) gravity with pressureless matter in an FRW spacetime. We construct an f(T) model by following the correspondence scheme incorporating a recently developed pilgrim dark energy model and taking the Hubble horizon as the IR cutoff. We use constructed model to discuss the evolution trajectories of the equation-of-state parameter, the ω _T -ω′ _T phase plane, and state-finder parameters in the evolving universe. It is found that the equation-of-state parameter gives a phantom era of the accelerated universe for some particular range of the pilgrim parameter. The ω _T -ω′ _T plane represents freezing regions only for an interacting framework, while the ΛCDM limit is attained in the state-finder plane. We also investigate the first and second laws of thermodynamics assuming equal temperatures at and inside the horizon in this scenario. Due to the violation of the first law of thermodynamics in f(T) gravity, we explore the behavior of the entropy production term. The validity of a generalized second law of thermodynamics depends on the present-day value of the Hubble parameter.     

Cosmic acceleration and Brans-Dicke theory

We study the accelerated expansion of the universe by exploring the Brans-Dicke parameter in different eras. For this, we take the FRW universe model with a viscous fluid (without potential) and the Bianchi type-I universe model with a barotropic fluid (with and without a potential). We evaluate the deceleration parameter and the Brans-Dicke parameter to explore cosmic acceleration. It is concluded that accelerated expansion of the universe can also be achieved for higher values of the Brans-Dicke parameter in some cases.     

Fermions tunneling from charged accelerating and rotating black holes with NUT parameter

We consider the production of the Standard Model Higgs boson through the gluon fusion mechanism in hadron collisions. We present the next-to-next-to-leading order (NNLO) QCD result of the hard-collinear coefficient function for the all-order resummation of logarithmically enhanced contributions at small transverse momentum. The coefficient function controls NNLO contributions in resummed calculations at full next-to-next-to-leading logarithmic accuracy. The same coefficient function is used in applications of the subtraction method to perform fully exclusive perturbative calculations up to NNLO.