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- Using the FLRW cosmological model, this paper explores the dynamics of perfect fluid as a source in the context of modified gravity, where the non-metricity Q, which causes the gravitational interaction, is represented by the arbitrary function Lagrangian as the trace of the non-metricity tensor Q, say f(Q) gravity. We govern the features of the derived cosmological model in view of the parameterization of Hubble’s parameter of the form, H(z)=H0(γ+1)(γ+(1+z)ξ). We have spoken about how the energy density, pressure, equation of state parameter, and skewness parameter in our model represent the physical behavior of the cosmos. In addition, we have looked at the kinematic parameters in our model that describe the cosmos, including the jerk, deceleration, and Hubble parameters. The universe’s phase transition from deceleration to acceleration is indicated by our model’s deceleration parameter, q(z). Furthermore, the deceleration parameter’s present value, q0 clearly aligns with the essential ΛCDM model. In order to determine the nature of the dark energy model, we also examined geometrical diagnostics such as the Statefinder pairs and Om(z) diagnostic. Additionally, we used the squared speed of sound test to examine the stability of the cosmos in our model. In the end, at present, the universe in our model is expanding, accelerating, and behaving in a manner consistent with a quintessential dark energy concept while at late the cosmos is dominated by ΛCDM.
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- In this paper, we investigate dust-fluid flat cosmological models in the recently proposed modified f(R,T,Lm)-gravity theory. We derive the field equations for the flat FLRW spacetime metric for the arbitrary function f(R,T,Lm)=R2+αT+βLmn−γ, where R is the Ricci curvature scalar, Lm is the matter Lagrangian, T is the trace of the energy–momentum tensor Tij, and α, β, γ, and n are the model parameters. We solve these equations to obtain the Hubble function in terms of matter energy density parameters Ωα0, Ωβ0, Ωγ0\, and Hubble constant H0. Then, we use the cosmic chronometer (CC) Hubble points dataset and the Pantheon dataset to do MCMC analysis of the Hubble function and find the best fit model parameters for the lowest χ2 values. Subsequently, we investigate the effective equation of state parameter ωeff and deceleration parameter q(z) for the present past epoch of the universe. We also perform analysis for energy conditions and state finder parameters to discuss the different stages of the dark energy models.
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- We investigate the cosmic evolution of the universe in context of f(R,G) gravity with homogeneous and isotropic background, where represents the Ricci scalar, and G denotes the Gauss–Bonnet invariant. With the field equations of the f(R,G) gravity in the non-flat spacetime, we examine the characteristics of model with two distinct forms: f1(R,G)=μRnGm and f2(R,G)=β1R+β2μRnGm, where n, m, β1 and β2 are the model parameters. The power-law solutions for the field equations are obtained by constraining the model parameters by employing Bayesian analysis tools in conjunction with the Markov Chain Monte Carlo (MCMC) method. We constraint the parameters by utilizing the combined datasets (OHD+BAO+Pantheon) for open Friedmann–Lemaitre–Robertson–Walker (FLRW) model. The parameters of power-law solutions are determined as H0=70.76732+0.00010−0.00088km/(s⋅Mpc) and q=−0.6478+0.000091−0.000075. The present dark energy model estimates H value higher than the Λ CDM model. This is one of the motivations to consider the f(R,G) gravity to describe dark energy era. The best-fit values of model parameters in an open model yield the power index of power-law solution as α=2.394949+.000089−0.00060. In the present model, the joint analysis by incorporating data from OHD, BAO, and Pantheon datasets favors the open FLRW model with power-law solutions at the late times. The behavior of cosmological parameters has been studied to explore the evolution of dark energy. The equation of state parameter (ω≃−1) supports the accelerated expansion of the Universe at late times. The energy conditions are also studied to test the cosmological viability of the model.
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- 2025| Pleiades Publishing ...In the context of F(T,TG)F(T,T G ) gravity, we examine the reconstruction scenario of the Tsallis holographic dark energy (THDE) model where TT stands for the torsion scalar, and TGT G stands for the teleparallel Gauss–Bonnet term. The Hubble constant H0H 0 and the deceleration value q q are two crucial elements that govern the expansion history of the Universe in power-law cosmology. Using the Markov Chain Monte Carlo (MCMC) technique with the likelihood function, we obtain the sets of constraints as H0=70.93−0.0037+0.0024H 0 =70.93 −0.0037+0.0024 km/s/Mpc, q=−0.33840.00260.0027q=−0.3384 0.0026+0.0027 for the Pantheon data and H0=70.76732−0.00088+0.0030H 0 =70.76732 −0.00088+0.0030 km/s/Mpc, q=−0.64780.0075+0.0093q=−0.6478 0.0075+0.0093 by using the joint data (OHD ++ BAO ++ Pantheon), respectively. We find that the considered data fit well with the power-law cosmology at late times. We also use the bulk-viscosity component to solve the modified Einstein’s field equations, ξ=ξ0+ξ1H+ξ2(H˙+H2)ξ=ξ 0 +ξ H+ξ 2 ( H˙ +H 2 ). We determine the universe’s current age to be 13.61813.618 Gyr, which is in line with the WMAP data. We additionally discussed the Om(z)Om(z) parameter of the derived model.
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- In this study, a new data-driven multivariate multiscale statistical process monitoring method based on singular spectrum analysis (SSA) and empirical mode decomposition (EMD) is proposed for fault detection in chemical process systems. SSA extracts the trends of process signals using the eigenvalues of trajectory matrices while EMD uses the intrinsic mode functions (IMFs) to capture the signal trends through sifting process. The results obtained from the industrial and simulated case studies showed that SSA and conventional multivariate statistical process monitoring technique such as principal component analysis (PCA) failed to extract the nonstationary and nonlinear trends in the signal effectively. As an alternative, in this study, SSA is combined with EMD decomposition prior to the process monitoring procedure using PCA. The efficiency of EMD in analyzing the nonstationary and nonlinear signals enhanced the performance of linear SSA techniques by combining the two techniques in this study. Experimental and simulation results also revealed that fault detection using EMD is comparable to the combined technique.
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- We have developed a Bianchi I cosmological model of the universe in f (R, T) gravity theory which fit good with the present-day scenario of accelerating universe. The model displays transition from deceleration in the past to the acceleration at the present. As in the CDM model, we have defined the three energy parameters, and such that++= 1. The parameter is the matter energy density (baryons+ dark matter), is the energy density associated with the Ricci scalar R and the trace T of the energy momentum tensor and is the energy density associated with the anisotropy of the universe. We shall call dominant over the other two due to its higher value. We find that the and the other two in the ratio 3: 1. 46 Hubble OHD data set is used to estimate present values of Hubble, deceleration and jerk j parameters. 1, 2 and 3 contour region plots for the estimated values of parameters are presented. 580 SNIa supernova distance modulus data set and 66 pantheon SNIa data which include high red shift data in the range have been used to draw error bar plots and likelihood probability curves for distance modulus and apparent magnitude of SNIa supernova’s. We have calculated the pressures and densities associated with the two matter densities, viz.,, and, respectively. The present age of the universe as per our model is also evaluated, and it is found at par with the present observed values.
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- 2022| World Scientific Pub...In this paper, we have investigated the physical behavior of cosmological models in the framework of modified teleparallel gravity. This model is established using a Rényi holographic dark energy (RHDE) model with a Hubble cut-off. Here, we have considered a homogeneous and isotropic Friedman universe filled with perfect fluid. The physical parameters are derived for the present model in compliances with 43 observational Hubble data sets. The equation-of-state parameter in terms of H(z) describes the transition of the universe between phantom and nonphantom phases in the context of f(T) gravity. Our model shows the violation of strong energy condition and the weak energy condition over the accelerated phantom regime. We also observed that these models occupy freezing regions through ωD-ωD′ plane. Consequently, our RHDE model is supported to the consequences of general relativity in the framework of f(T) modified gravity.
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- In the present work, we investigate the power-law entropy corrected holographic dark energy (PLECHDE) model with Hubble horizon cutoff. We use 46 observational Hubble data points in the redshift range 0 ≤ 𝑧 ≤ 2.36 to determine the present Hubble constant 𝐻0 and the model parameter 𝑛. It represents a phase transition of the universe from deceleration to acceleration and has the transition point at 𝑧𝑡 = 0.71165. We investigate the observational constraints on the model and calculate some relevant cosmological parameters. We examine the model’s validity by drawing state-finder parameters that yield the result compatible with the modern observational data. The model’s physical and geometrical characteristics are also explored, and they are shown to match well with current observations of observational Hubble data (OHD) and the latest joint light curves(JLA) datasets.
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- Singular spectrum analysis (SSA) has become a popular and widely used forecasting and pre-processing technique in time series analysis which is currently exploited in chemical process monitoring and fault detection. Given its increased application and superior performance in comparison to conventional multivariate methods such as Principal Component Analysis (PCA) and Wavelets and its nonlinear extensions, it is relevant to study the variants of SSA and its applications in process monitoring. In this study SSA is combined with Kernel Multidimensional Scaling called Kernel Dissimilarity Scale Based Singular Spectrum Analysis (KDSSA) and is used to detect the faults in the Tennessee Eastman Process (TEP). The methodology is focused on three particular faults which were not observable with conventional multivariate methods and its no nlinear extensions. The monitoring results showed that the proposed method is efficient in detecting those faults in reduced number of modes. A unified monitoring index combined T2 statistics with Q statistics is used to simplify the fault detection task.
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- 2019| PONTE Journal and Am...This theoretical enquiry was geared towards the formation and advancement of a scholarly discourse in the context of higher education practitioners’ levels of assessment literacy. Despite having recently gained an unprecedented level of currency among academics, assessment literacy, as a higher education professional attribute, remains largely not theorised. The related scholarly thought has mostly evolved around a particular emancipatory discourse. Such thinking is also underpinned by a certain degree of subservience to the conventional notions of professional ethics and morality that subsumes assessment literacy. The emergence of the higher education transformation discourse has also resulted in trepidations felt at individual and institutional levels, further confounding assessment-related professional attributes as a ripple effect. A conceptual consolidation of the idea of assessment as a professional literacy, together with its associated constructs, is therefore mooted here. The practice of assessment-literacy-related professional development subscribing to the notions of critical theory, critical reflection, and 21 st century skills, was hence philosophically substantiated, so that such practices assume a higher degree of legitimacy and credence. Assessment, the single most dominant student experience, as this article concludes, needs significant philosophical reaffirmation. Such a reaffirmation forms the basis for the continuance of progressive discourses, and is hence vital in the context of advancement of assessment literacy as an aspect of higher education professional literacy. Abstract should be between 200-500 words. Font Size 12, Times New Roman.
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