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Globally, grid systems are facing substantial challenges due to the rapid growth in power demand. New technologies equipped by means of smart energy resources are one promising solution to cope with this challenge, leading to microgrid systems. The growing demand to develop the power sector by utilizing alternative energy resources plays an influential role in the advancement of low-voltage DC (LVDC) systems. With the prompt development of LVDC distribution grids, bipolar LVDC distribution topology is becoming a leading and promising solution. Therefore, this review paper represents a comprehensive overview as well as a comparative and critical analysis for the development of novel methods on LVDC grid analysis, control strategy, and protection schemes to solve energy management problems that lead to a futuristic novel solution in the green revolution. [ABSTRACT FROM AUTHOR]

Assuming that viscous fluid in the form of Barrow holographic dark energy (BHDE) (a particular case of more generalized version of HDE elaborated in Nojiri et al. in Phys Lett B 825:136844, 2022; Symmetry 13(6):928, 2021) and pressure-less dark matter are present across the flat Friedmann–Robertson–Walker universe, we find the precise solutions of viscous BHDE models in non-interacting and interacting scenarios for different choices of scale factor. We show the evolution of the EoS parameters in the viscous non-interacting and interacting situations together with the deceleration parameters for observing the transition time frame. Afterwards, we investigate a bounce inflation model using the analytical results of model’s slow-roll parameters, scalar spectral index, and tensor-to-scalar ratio. We investigated an association between BHDE and scalar field models since inflation is typically attributed to the existence of scalar fields. The evolution of the generated potential from the scalar fields are plotted against time. Finally, we investigated the GSL of the thermodynamics. [ABSTRACT FROM AUTHOR]

Post-monsoon and winter months cater to conditions such as temperature inversions, crop-residue burning, and firecracker bursting, which enhance air pollution. Utilizing this scenario, this work uses a fuzzy set theory-based approach to explore the interrelationship between different pairs of pollutants. Conducted over Kolkata during the post-monsoon and winter months, the study comprises PM2.5, PM10, NOx, SO2, O3, and temperature as the random variables. Through the computation of descriptive statistics, hypothesis testing through the chi-square test, and quantification of uncertainty by Shannon entropy, we found a lack of symmetry and the presence of uncertainty in the data. In this view, we have considered binary fuzzy relation (BFR) in its raw form and through max–min composition on the random variables to analyze the interrelationship between the pollutants and analyzed the results accordingly. Projections of binary fuzzy relations have supplemented the results. The study concluded that temperature and SO2 can play a significant role in modeling PM2.5, including the effect of PM10.Highlights: Post-monsoon and winter months cater several conditions such as temperature inversions, crop-residue burning, and firecracker bursting, which enhance air pollution. Conducted over Kolkata during the post-monsoon and winter months, the study comprises of PM2.5, PM10, NOx, SO2, O3, and temperature as the random variables. Through quantification of uncertainty by Shannon entropy, we found lack of symmetry and presence of uncertainty in the data. We applied binary fuzzy relation (BFR) in its raw form and through max–min composition on the random variables. Examining the influence of PM10 on the pair of NOx and SO2, we observe that SO2 can play a significant role in model NOx, inclusive of the effect of PM10. [ABSTRACT FROM AUTHOR]

The work presented here reports a detailed analysis of the rainfall over the Eastern Peninsula region of India (EPI) using Markov chain analysis. We have observed through normal distribution fitting that the overall pattern of annual rainfall is influenced by the Indian summer monsoon rainfall (ISMR), and the post-monsoon season has fewer roles to play in the overall pattern of annual rainfall over the eastern peninsula of India. A Markovian analysis has shown that the rainfall time series, discretized to a binary time series, is serially independent. Finally, we have conducted a rescaled range analysis for all the time series under consideration. We have observed that in all three cases, the Hurst exponent is less than 0.5. We have concluded that strong long-term auto-correlation does not characterize the time series. Instead, there exists long-term switching between high and low values of rainfall. [ABSTRACT FROM AUTHOR]

In this paper we have discussed the modified gravity and scalar field DE model specifically DBI essence model with the analysis of thermodynamics during cosmological evolution. We have used the modified gravity with the form f R , T = R + 2 λ T in our calculations. The basic aim behind this paper is to discuss a theory that unifies modified gravity with DE models including the solutions of some cosmological problems like thermodynamics energy conditions violation problems, finite time future singularity problems, initial singularity problem, cosmic inflation problem, decelerated expansion problem, graceful exit problem, reheating problem, bouncing nature problem, phase transformation-spontaneous symmetry breaking problem, negative heat capacity paradox problem and obviously the present-day universe problems (continuously decreasing temperature problem and present-day DE dominated expansion problem). We have established the viscous effects (both positive and negative viscosity) in our calculation and discussed the negative–positive viscosity by introducing two special type of energy cycles. Finally, we have discussed the stability conditions for universe evolution through cosmic perturbation and resolved the instability problems. We have also shown the state finder trajectories for both with and without viscous fluid on the basis of our calculations to compare our research with the results of other independent DE models. [ABSTRACT FROM AUTHOR]

The present study reports a multifractal detrended fluctuation analysis (MF-DFA) of total ozone time series. Considering daily total ozone concentration (TOC) data ranging from 2015 to 2019, derived from Ozone Monitoring Instrument (OMI)/Aura observations, we have created a new profile by subtracting the trend. Subsequently, we have divided the profile X i into non-intersecting segments of equal time scale varying from 25 to 30. Fitting a second order polynomial, we have eliminated the local trend from each segment, and thereafter, we have computed the detrended variance. Finally, the multifractal behaviour has been identified, and the singularity spectra has helped us in obtaining the generalised Hurst exponent which in this case has come out to be greater than 0.5. [ABSTRACT FROM AUTHOR]

A tropical cyclone is one of the most devastating meteorological events. In recent years, we faced some very severe cyclones to a super cyclone successively that caused heavy damages to life and property during the helpless situations of the global pandemic. In this paper, we studied the frequency of cyclones from the years 1891 to 2019, i.e., for 129 years, on the Arabian Sea Basin, Bay of Bengal Basin, and land. We have categorized the cyclones according to their wind speeds: (i) cyclonic storms and severe cyclonic storms (CS + SCS) and (ii) depressions, cyclonic storms, and severe cyclonic storms (D + CS + SCS) where depressions, cyclonic storms, and severe cyclonic storms have wind speeds of more than or equal to 17 knots, 34 knots, and 48 knots respectively. We examined the Markovian dependence of the discretized time series of the two categories mentioned earlier for the first, second, third, and fourth order of a two-state Markov chain model. It is found that CS + SCS represents the first-order two-state (FOTS) model of Markov chain and D + CS + SCS represents the second-order two-state (SOTS) model of Markov chain. Thereafter, we have developed autoregressive models for the two categories and checked their goodness of fit using Willmott's indices of orders 1 and 2. It is found that CS + SCS best represents the autoregressive model of order 5, whereas D + CS + SCS could not be efficiently represented by the developed autoregressive models. So we further developed autoregressive neural networks for D + CS + SCS and obtained a significant hike in the prediction yield. Nevertheless, it is found that both categories are not serially independent. [ABSTRACT FROM AUTHOR]

The present paper reports a rigorous study of the Indian Summer Monsoon Rainfall (ISMR) through Multifractal Detrended Fluctuation Analysis (MF-DFA). It has been observed that the ISMR is characterized by multifractality and Hurst Exponent above 0.5. It has been interpreted from the Hurst Exponent value that the ISMR time series is characterized by long term positive auto-correlation. Studying the strong correlation between the qthorder fluctuation and the length scale the multifractality has been confirmed within the ISMR time series. Finally, the entropy associated with ISMR has been computed using the principle of entropy maximization and the potential of entropy maximizing principle has been established over conventional fitting of normal distribution to ISMR. [ABSTRACT FROM AUTHOR]

The paper reports a study on the air quality over Kolkata, India during the transition period from post-monsoon to winter. A fuzzy binary relation based approach is implemented to O3, N O2 and P M2 5 and the overall air quality index (AQI). Individual pollutants have been converted to fuzzy sets based on their concentrations as elements of the universe of discourse with appropriate fuzzy membership functions defined on them. AQI has been divided into categories based on the recommendations of the Central Pollution Control Board (CPCB), Govt of India. After defining the fuzzy relations, the fuzzy composite relations have been derived to construct fuzzy membership matrices based on the composite binary fuzzy relations. Afterwards, the membership grades of the matrices for the composite fuzzy binary relations have been studied and N O2 along with O3 have been consideblack as having highly significant influence on the overall AQI over the polluted study zone during the transition from post-monsoon to winter. [ABSTRACT FROM AUTHOR]

The current research reports a univariate analysis of 2 important climatological parameters surface air temperature and rainfall over North East India over annual scale characterized by various degrees of non-linearity. An Autocorrelation study reveals that although the surface air temperature is characterized by an approximate sinusoidal pattern, the rainfall has no apparent pattern. As both the time series have continuous random variables associated with it we need a discretization to make them suitable for study in time domain. First, we test for Markovian behavior against serial independence. By appropriate discretization of both the time series the transition probabilities are computed to test for Two State Markov Chain model with different orders. A chi square test reveals that although the surface air temperature time series follows the Markov Chain model of 1st Order, the annual rainfall is serially independent. The steady state transition probabilities are computed for surface air temperature and subsequently autoregressive models upto order 4 with the help of Yule-Walker Equations. It was further observed that the 2nd order model satisfied the stationarity conditions. Subsequently to have a general overview of the stationarity, Unit Root Test is carried out for both the time series. For surface air temperature a root was found to exist inside the circumference of the unit circle while for rainfall time series finds a root of the characteristic equation outside unit circle. This indicates stationarity of the surface air temperature time series for its 1st order differences and non-stationarity of rainfall time series. Based on this, Autoregressive Integrated Moving Average (ARIMA(p,q,d)) model is fitted to the rainfall time series for various orders of Autoregression and differencing. Subsequently the performance of ARIMA has been compared to univariate artificial neural network model with 4 successive realizations as predictor and the 5th one as predictand. In order to test the relative contributions to these meteorological phenomenon, maximization of Shannon entropy is used. [ABSTRACT FROM AUTHOR]

The present study reports a two-state Markov chain approach as well as an autoregressive approach to study the behavior of the surface temperature time series over northeast India. Considering the minimum requirement of the chi-square test, 1998–2007 (> 100 months) have been considered for testing the Markovian and autoregressive behavior. The monthly surface temperature time series involves monthly data that corresponds to a continuous random variable. This random variable has been discretized to binary data, and the transition probabilities have been computed up to the fourth-order Markov chain model. The best order of Markov chain has been derived through the minimization of the Bayesian information criterion (BIC). By analyzing the time series autocorrelation function and the Akaike information criteria (AIC), the autoregressive model of order two has been found to be a representative and the best autoregressive method for the average monthly time series of surface temperatures over northeast India. [ABSTRACT FROM AUTHOR]

The present work reports a study on the behavior of the time series of rainfall during the summer monsoon (June–September) in northeast India. It has been observed through hypothesis testing that although a normal distribution fits the time series, no persistence forecast is possible as indicated by the low value of the Lag-1 autocorrelation coefficient (0.041). A linear regression over time is not a good fit. Subsequently, the intrinsic behavior of the time series has been explored through Hurst exponent (H) computed using rescaled range analysis. The value of the Hurst exponent is in the range of 0 < H < 0.5, and from this range, it could be understood that long-term switching is expected to exist between high and low values in adjacent pairs. However, when the Hurst exponent value is being low, the summer monsoon rainfall over northeast India has been thought of as characterized by volatility and roughness. Finally, the connectivity of the El Niño-Southern Oscillation (ENSO) to the Indian summer monsoon rainfall has been briefly discussed in light of the long-term behavior. [ABSTRACT FROM AUTHOR]

The present study reports a thorough information theory–based investigation of the time series of rainfall in seasonal scale as well as yearly scale in the Himalayas during the summer monsoon (June–September). In this paper, the inbred uncertainty of rainfall series has been evaluated through Shannon entropy by fitting a probability distribution. The entropy has been measured for seasonal scales as well as yearly scales. A few parameters relating to the summer monsoon rainfall series over parts of North Mountainous India (NMI) from 1844 to 2005 are considered for computing entropy. Maximization of Shannon entropy is done to examine the parallel contributions of these parameters in this meteorological phenomenon. Finally, we have shown how entropy is affected by the fluctuation of mean rainfall in seasonal scale as well as yearly scale. We have also computed the decade-wise intrinsic uncertainty of rainfall series as rainfall is the most important parameter for climate risk. Besides, we also fitted the probability distribution curve generated by rainfall series. [ABSTRACT FROM AUTHOR]

Work reported in the present study considers hourly concentration of five pollutants NO2, O3, PM2.5, PM10 and SO2 over Kolkata, a megacity of India on two major festive days, namely "Kali Puja" and "Diwali" characterized by excessive use of fireworks emitting hazardous gases. Markov chains up to fourth order have been tested for all these pollutants by discretizing the concentration data leading to binary time series. After checking the Markovian status through Chi-square test based on the null hypothesis of serial independence, the Bayesian information criterion (BIC) has been computed to identify the proper order of Markov chain by minimization of BIC. It has been observed that the first-order two-state Markov chain is the most dominant Markov chain characterizing the hourly data of all the pollutants on the said festive days. Finally, it has been concluded the excessive use of fireworks leads to randomness within the hourly concentration of the pollutants. Article Highlights: Work reported in the present study considers hourly concentration of five pollutants NO2, O3, PM2.5, PM10 and SO2 over Kolkata, a megacity of India on two major festive days, namely "Kali Puja" and "Diwali" characterized by excessive use of fireworks emitting hazardous gases. Two-state Markov chain model has been tested for the hourly data of the pollutants. Bayesian information criterion (BIC) has been computed to identify the proper order of Markov chain by minimization of BIC. It has been observed that the first-order two-state Markov chain (FOTSMC) is the most dominant Markov chain characterizing the hourly data of all the pollutants on the said festive days. Finally, it has been concluded the excessive use of fireworks leads to randomness within the hourly concentration of the pollutants. [ABSTRACT FROM AUTHOR]

An information theoretic approach based on Shannon entropy is adopted in this study to discern the influence of pre-monsoon thunderstorm on some surface parameters. A few parameters associated with pre-monsoon thunderstorms over a part of east and northeast India are considered. Maximization of Shannon entropy is employed to test the relative contributions of these parameters in creating this weather phenomenon. It follows as a consequence of this information theoretic approach that surface temperature is the most important parameter among those considered. Finally, artificial neural network in the form of multilayer perceptron with backpropagation learning is attempted to develop predictive model for surface temperature. [ABSTRACT FROM AUTHOR]

The present paper reports a study, where growing hierarchical self-organising map (GHSOM) has been applied to achieve a visual cluster analysis to the Indian rainfall dataset consisting of 142 years of Indian rainfall data so that the yearly rainfall can be segregated into small groups to visualise the pattern of clustering behaviour of yearly rainfall due to changes in monthly rainfall for each year. Also, through support vector machine (SVM), it has been observed that generation of clusters impacts positively on the prediction of the Indian summer monsoon rainfall. Results have been presented through statistical and graphical analyses. [ABSTRACT FROM AUTHOR]

In this paper, we study the properties of the Holographic Dark Energy (HDE) model in the context of Kaluza-Klein (KK) cosmology with infrared cut-off given by the recently proposed by Granda-Oliveros cut-off, which contains a term proportional to the time derivative of the Hubble parameter and one proportional to the Hubble parameter squared. Moreover, this cut-off is characterized by two free parameters which are the proportional constants of the two terms of the cut-off. We derive the expression of the Equation of State (EoS) parameter $ \omega_{D}$ and of the deceleration parameter q for both non-interacting and interacting Dark Sectors and in the limiting case of a flat Dark Dominated Universe. Moreover, we study the squared speed of the sound $ v_{s}^{2}$ and the statefinder diagnostic $ \{r,s\}$ in order to understand the cosmological properties of the model considered. We also develop a correspondence between the model considered and three scalar field models: the tachyon, the k-essence and the quintessence ones. [ABSTRACT FROM AUTHOR]

The new complexes of compositions [(L)Cu] and [(L)Cu] were prepared by treating with 2-hydroxy-5-methyl-3-(2-aryldiazenyl)phenylimino) methyl) benzaldehyde (HL) and ethyl-2-cyano-3-(2-hydroxy-5-methyl-3-(-(2-aryldiazenyl) phenylimino) methyl) phenyl) acrylate (HL) ligands [where aryl is phenyl for HL $_{\mathrm {a}}^{\mathrm {~1 } }$ and HL $_{\mathrm {b}}^{~1}$; p-methyl phenyl for HL $_{\mathrm {a}}^{\mathrm {~2 } }$ and HL $_{\mathrm {b}}^{~2}$; and p-chloro phenyl for HL $_{\mathrm {a}}^{\mathrm {~3 } }$ and HL $_{\mathrm {b}}^{~3}$] with Cu(OAc).HO, respectively. Both the bis copper(II) complexes consist of tridentate (N,N,O) anionic ligands, L $_{\mathrm {a}}^{\mathrm {~-}}$ or L $_{\mathrm {b}}^{\mathrm {~-}}$. X-ray structures of the representative complexes [(L $_{\mathrm {a}}^{~1})_{2}$Cu] and [(L $_{\mathrm {b}}^{~2})_{2}$Cu] were determined to confirm the molecular species unequivocally. The molecular structure of copper complexes exhibited tetragonally distorted (Jahn-Teller) geometry consistent with the d configuration of Cu(II) metal ion. Oxidation of benzyl alcohols using the newly synthesized complexes as catalyst has been studied. Photoluminescence properties of [(L $_{\mathrm {a}}^{~2})_{2}$Cu] and [(L $_{\mathrm {b}}^{~2})_{2}$Cu] were exploited for selective cyanide recognition. The [(L)Cu], complexes displayed antibacterial activity toward gram positive and gram negative bacteria. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

In this paper, we explore the reconstruction scenario of modified QCD ghost dark energy model and newly proposed $f(T,T_{G})$ gravity in flat FRW universe. We consider the well-known assumption of scale factor, i.e., power law form. We construct the $f(T,T_{G})$ model and discuss its cosmological consequences through various cosmological parameters such as equation of state parameter, squared speed of sound and $\omega_{\mathit{DE}}-\omega '_{\mathit{DE}}$. The equation of state parameter provides the quintom-like behavior of the universe. The squared speed of sound exhibits the stability of model in the later time. Also, $\omega_{\mathit{DE}}- \omega '_{\mathit{DE}}$ corresponds to freezing as well as thawing regions. It is also interesting to remark here that the results of equation of state parameter and $w_{\mathit{DE}}-w'_{\mathit{DE}}$ coincide with the observational data. [ABSTRACT FROM AUTHOR]

Motivated by the quantum essence of wormholes, in this work, we have studied accretion of dark energy (DE) onto Morris-Thorne wormhole with three different forms, namely, holographic dark energy, holographic Ricci dark energy and modified holographic Ricci dark energy. Considering the scale factor in power-law form we have observed that as the holographic dark energy accretes onto wormhole, the mass of the wormhole is decreasing. In the next phase we considered three parameterization schemes that are able to get hold of quintessence as well as phantom phases. Without any choice of scale factor we reconstructed Hubble parameter from conservation equation and dark energy densities and subsequently got the mass of the wormhole separately for accretion of the three dark energy candidates. It was observed that if these dark energies accrete onto the wormhole, then for quintessence stage, wormhole mass decreases up to a certain finite value and then again increases to aggressively during phantom phase of the universe. [ABSTRACT FROM AUTHOR]

In this work, we studied the Power Law and the Logarithmic Entropy Corrected versions of the Ricci Dark Energy (RDE) model in a spatially non-flat universe and in the framework of Hořava-Lifshitz cosmology. For the two cases containing non-interacting and interacting RDE and Dark Matter (DM), we obtained the exact differential equation that determines the evolutionary form of the RDE energy density. Moreover, we obtained the expressions of the deceleration parameter q and, using a parametrization of the equation of state (EoS) parameter ω given by the relation ω( z) = ω+ ω z, we derived the expressions of both ω and ω. We interestingly found that the expression of ω is the same for both non-interacting and interacting case. The expression of ω for the interacting case has strong dependence from the interacting parameter b. The parameters derived in this work are done in small redshift approximation and for low redshift expansion of the EoS parameter. [ABSTRACT FROM AUTHOR]

Dark energy models are here investigated and studied in the framework of the Chern-Simons modified gravity model. We bring into focus the holographic dark energy model with Granda-Oliveros cut-off, the modified holographic Ricci dark energy model and a model with higher derivatives of the Hubble parameter. The relevant expressions of the scale factor $$a(t)$$ for a Friedmann-Robertson-Walker Universe are derived and studied, and, in this context, the evolution of the scale factor is shown to be similar to the one displayed by the modified Chaplygin gas in two of the above models. [ABSTRACT FROM AUTHOR]

We work on the reconstruction scenario of pilgrim dark energy (PDE) in f( T, T). In PDE model it is assumed that a repulsive force that is accelerating the Universe is phantom type with ( w<−1) and it is so strong that prevents formation of the black hole. We construct the f( T, T) models and correspondingly evaluate equation of state parameter for various choices of scale factor. Also, we assume polynomial form of f( T, T) in terms of cosmic time and reconstruct H and w in this manner. Through discussion, it is concluded that PDE shows aggressive phantom-like behavior for s=−2 in f( T, T) gravity. [ABSTRACT FROM AUTHOR]

In this paper, we study the new holographic dark energy model in the framework of modified f( R) Horava-Lifshitz Gravity. We apply correspondence scheme to construct model the in underlying scenario using power-law form of scale factor. To explore accelerated expansion of the universe, some well-known cosmological parameters (equation of state parameter and squared speed of sound) and cosmological planes ( ω- $\omega'_{\varLambda}$ and statefinder) are discussed for reconstructed model. It is interesting to conclude that these parameters represent phantom behavior of the universe with stable configuration. also, the cosmological planes show compatible results with recent observations for accelerated expansion of the universe. [ABSTRACT FROM AUTHOR]

In this paper, we studied the cosmological application of the interacting Ricci Dark Energy (RDE) model in the framework of the scalar Gauss-Bonnet modified gravity model. We studied the properties of the reconstructed potential $V\left (t \right )$, the Strong Energy Condition (SEC), the Weak Energy Condition (WEC) and the deceleration parameter q for three different models of scale factor, i.e. the emergent, the intermediate and the logamediate one. We obtained that $V\left (t \right )$, for the emergent scenario, has a decreasing behavior, while, for the logamediate scenario, the potential start with an increasing behavior then, for later times, it shows a slowly decreasing behavior. Finally, for the intermediate scenario, the potential has an initial increasing behavior, then for a time of t≈1.2, it starts to decrease. We also found that both SEC and WEC are violated for all the three scale factors considered. Finally, studying the plots of q, we derived that an accelerated universe can be achieved for the three models of scale factor considered. [ABSTRACT FROM AUTHOR]

Considering power-law for of scale factor in a flat FRW universe we reported a reconstruction scheme for f( G) gravity based on QCD ghost dark energy. We reconstructed the effective equation of state parameter and observed 'quintessence' behavior of the equation of state parameter. Furthermore, considering dynamical apparent horizon as the enveloping horizon of the universe we have observed that the generalized second law of thermodynamics is valid for this reconstructed f( G) gravity. [ABSTRACT FROM AUTHOR]

In this work, we discussed a new dark energy density model which contains one term proportional to the Hubble parameter H squared, one to the first and one to second time derivative of the Hubble parameter H based on El-Nabulsi fractional action cosmology (FAC). Some cosmological parameters, like the Hubble parameter, the Equation of State (EoS) parameter ω and the deceleration parameter q have been reconstructed and studied. Finally, through a test made using the squared speed of sound $v_{s}^{2}$, the proposed reconstruction model results to be classically unstable. [ABSTRACT FROM AUTHOR]

In this paper, we consider the New Agegraphic Dark Energy (NADE) model interacting with pressureless Dark Matter (DM) in the framework of generalized uncertainty principle. We consider different expressions of the scale factor a( t) pertaining to the emergent, the intermediate and the logamediate scenarios of the universe. We have derived the expressions for various cosmological parameters in all the three cases and plotted the equation of state (EoS) parameter ω and squared speed of the sound $v_{s}^{2}$ to check the stability of the model in each case. We have observed that for emergent and intermediate cases, the EoS parameter has a quintom-like behavior and in the logamediate case it has quintessence-like behavior. The negative squared speed of sound in all of the three cases has indicated that the model is classically unstable for each choice of scale factor. [ABSTRACT FROM AUTHOR]

This paper reports a study on the cosmological application of interacting Ricci Dark Energy (RDE) density in the scalar Gauss-Bonnet framework. The interacting holographic RDE model has been employed to obtain the equation of state (EoS) in a spatially flat universe. The main results of this paper are that the reconstructed potential of scalar Gauss-Bonnet gravity for the interacting RDE model decays with the evolution of the universe. However, it is an increasing function of the scalar field $ \phi$ . Both the strong and weak energy conditions are violated. A phantom-like behavior of the EoS parameter has been obtained. The effective EoS parameter $ \omega_{eff}$ stays below -1 but tends to -1 with the evolution of the universe. However, it cannot cross the phantom boundary. Finally, the interacting RDE model in Gauss-Bonnet gravity gives accelerated expansion of the universe. [ABSTRACT FROM AUTHOR]

In this work, we studied the Logarithmic Entropy-Corrected Holographic Dark Energy (LECHDE) model in a spatially non-flat universe and in the framework of Hořava-Lifshitz cosmology. As infrared cutoff of the system we considered the cut-off recently proposed by Granda and Oliveros which contains two terms, one proportional to H and one to $\dot{H}$. For the two cases containing non-interacting and interacting Dark Energy (DE) and Dark Matter (DM), we obtained the exact differential equation that determines the evolution of the density parameter. Moreover, we derived the expressions of the deceleration parameter q and, using a parametrization of the equation of state (EoS) parameter ω of our model as ω( z)= ω+ ω z, we derived both the expressions of ω and ω for both non-interacting and interacting cases. All derivations made in this work are done in small redshift approximation and for low redshift expansion of the equation of state (EoS) parameter. [ABSTRACT FROM AUTHOR]

In this paper, we reconstruct the holographic dark energy in the framework of the f ( G) modified theory of gravity, where G is the Gauss-Bonnet invariant. In this context, we choose the infrared cut-off as the Granda-Oliveros cut-off, which is proportional to the Hubble parameter H and its first derivative with respect to the cosmic time t . We reconstruct the f ( G) model with the inclusion of HDE and the three well-known forms of the scale factor a( t) , i.e. the emergent, the logamediate and the intermediate scale factors. The reconstructed model as well as equation of state parameter are discussed numerically with the help of graphical representations to explore the accelerated expansion of the universe. Moreover, the stability of the models incorporating all the scale factors is checked through squared speed of sound vs2. [ABSTRACT FROM AUTHOR]

Abstract.: The present paper reports a study on the dimensionless parameter $ \omega$ in Brans-Dicke theory. Based on a particular choice of scale factor a , we have investigated the signature flip of the deceleration parameter q to see whether the transition from decelerated to accelerated expansion of the universe is achievable under this choice of scale factor. Restrictions on the parameters obtained for this choice of scale factor have been subsequently used for discussing the Brans-Dicke parameter for two choices of scalar fields $ \phi$ . Moreover, analytical solutions for the Brans-Dicke parameter without any assumption about the scalar field have been obtained from the modified field equations through the choice of scale factor under consideration. Viable models have been obtained by comparing the results with observations. [ABSTRACT FROM AUTHOR]

In this work, we study the New Agegraphic Dark Energy (NADE) model (which contains the conformal time η as infrared cut-off) in the framework of Brans-Dicke cosmology with chameleon scalar field which is non-minimally coupled to the matter field. Considering interacting Dark Energy and Dark Matter (DM), we calculate some relevant cosmological parameters, i.e. the equation of state (EoS) parameter, the deceleration parameter q and the evolution of the energy density parameter $\varOmega_{D}'$ for different forms of scale factors, i.e. the power-law, the emergent, the intermediate and the logamediate ones, which leads to different expressions of η. [ABSTRACT FROM AUTHOR]