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.     

Structure scalars for charged cylindrically symmetric relativistic fluids

We investigate some structure scalars developed through Riemann tensor for self-gravitating cylindrically symmetric charged dissipative anisotropic fluid. We show that these scalars are directly related to the fundamental properties of the fluid. We formulate dynamical-transport equation as well as the mass function by including charge which are then expressed in terms of structure scalars. The effects of electric charge are investigated in the structure and evolution of compact objects. Finally, we show that all possible solutions of the field equations can be written in terms of these scalars.     

Computational analysis of supersonic turbulent boundary layers over rough surfaces using the k–ω and the stress–ω models

The influence of surface roughness in the prediction of the mean flow and turbulent properties of a high-speed supersonic (M = 2.7, Re/m = 2 × 10⁷) turbulent boundary layer flow over a flat plate is numerically investigated. In particular, the performance of the k–ω and stress–ω turbulence models is evaluated against the available experimental data. Even though the performance of these models have been proven satisfactory in the computation of incompressible boundary layer flow over rough surfaces, their validity for high-speed compressible has not been investigated yet. It is observed from this study that, for smooth surface, both k–ω and stress–ω models perform very well in predicting the mean flow and turbulence quantities in supersonic flow. For rough surfaces, both models matched the experimental data fairly well for lower roughness heights but performed unsatisfactorily for higher roughness conditions. Overall the performance of the k–ω model is better than the stress–ω model. The stress–ω model does not show any strong advantages to make up for the extra computational cost associated with it. The predictions indicate that the ω boundary conditions at the wall in both models, especially the stress–ω model, need to be refined and reconsidered to include the geometric factor for supersonic flow over surfaces with large roughness values.     

Hollow fiber liquid-phase microextraction for the determination of trace amounts of rosiglitazone (anti-diabetic drug) in biological fluids using capillary electrophoresis and high performance liquid chromatographic methods

A three-phase hollow fiber liquid-phase microextraction (HF-LPME) coupled either with capillary electrophoresis (CE) or high performance liquid chromatography (HPLC) with UV detection methods was successfully developed for the determination of trace levels of the anti-diabetic drug, rosiglitazone (ROSI) in biological fluids. The analyte was extracted into dihexyl ether that was immobilized in the wall pores of a porous hollow fiber from 10 mL of aqueous sample, pH 9.5 (donor phase), and was back extracted into the acceptor phase that contained 0.1 M HCl located in the lumen of the hollow fiber. Parameters affecting the extraction process such as type of extraction solvent, HCl concentration, donor phase pH, extraction time, stirring speed, and salt addition were studied and optimized. Under the optimized conditions (extraction solvent, dihexyl ether; donor phase pH, 9.5; acceptor phase, 0.1 M HCl; stirring speed, 600 rpm; extraction time, 30 min; without addition of salt), enrichment factor of 280 was obtained. Good linearity and correlation coefficients of the analyte was obtained over the concentration ranges of 1.0–500 and 5.0–500 ng mL⁻¹ for the HPLC (r² = 0.9988) and CE (r² = 0.9967) methods, respectively. The limits of detection (LOD) and limits of quantitation (LOQ) for the HPLC and CE methods were (0.18, 2.83) and (0.56, 5.00) ng mL⁻¹, respectively. The percent relative standard deviation (n = 6) for the extraction and determination of three concentration levels (10, 250, 500 ng mL⁻¹) of ROSI using the HPLC and CE methods were less than 10.9% and 13.2%, respectively. The developed methods are simple, rapid, sensitive and are suitable for the determination of trace amounts of ROSI in biological fluids.     

Unexpected Reduction of Indole Double Bond in Mitragynine Using n-Butylsilane and Catalytic Tris(pentaflorophenyl)borane

An unexpected reduction of indolic double bond of mitragynine was described by using n-butyl silane and tris(pentafluorophenyl)triborane.     

Parametric study of FENE and FENE-P models in steady and unsteady flow in a circular pipe using CONNFFESSIT approach

The temporal rheological behavior of FENE and FENE-P models is investigated using the flow in a circular, straight tube. The CONNFFESSIT approach is applied to simulate transient Hagen–Poiseuille flow for different pressure drops and model parameters. The material functions for steady and unsteady flow were extracted and compared with the reported values in the literature when it was available. For the case of the FENE model, where there is no analytical solution, the relationship between model parameters and rheological behavior has been discussed and compared with the FENE-P model.