Narrow Results

This study examines a dark energy cosmological model in the classical domain, where a generic scalar field is considered a dark energy source. Einstein’s field equations are solved in a model independent way, i.e. using a scheme of cosmological parametrization. A simple parametrization of the density parameter as a function of the cosmic scale factor is considered and investigated extensively. The results obtained are noteworthy as it shows a smooth transition from a decelerating to an accelerating phase in the recent past. Certain external datasets are used here to limit the model parameters involved in the functional form of the considered parametrization of energy density of the scalar filed. The updated Hubble datasets containing 57 data points, 1048 points of recently compiled Pantheon datasets, and also the Baryon Acoustic Oscillation (BAO) datasets are used here to determine the best-fitting model parameter values. The expressions of several significant cosmological parameters are represented as a function of redshift “$z$” and illustrated visually for the best fit values of the model parameters to better comprehend cosmic evolution. The obtained model is also compared with the $\mathrm{\Lambda }$CDM model. Our model has a distinct behavior in future and shown a big crunch type collapse. The best fit values of the model parameters are also used to compute the current values of several physical and geometrical parameters, as well as phase transition redshift. To examine the nature of dark energy, certain cosmological tests and diagnostic analyses are done on the derived model.

We study the thermodynamic properties of the Bose–Einstein condensate (BEC) in the context of the quantum field theory with noncommutative target space. Our main goal is to investigate in which temperature and/or energy regimes the noncommutativity can characterize some influence on the BEC properties described by a relativistic massive noncommutative boson gas. The noncommutativity parameters play a key role in the modified dispersion relations of the noncommutative fields, leading to a new phenomenology. We have obtained the condensate fraction, internal energy, pressure and specific heat of the system and taken ultrarelativistic (UR) and nonrelativistic (NR) limits. The noncommutative effects on the thermodynamic properties of the system are discussed. We found that there appear interesting signatures around the critical temperature.

In this paper, we have considered flat Friedmann–Robertson–Walker (FRW) model of the universe and reviewed the modified Chaplygin gas as the fluid source. Associated with the scalar field model, we have determined the Hubble parameter as a generating function in terms of the scalar field. Instead of hyperbolic function, we have taken Jacobi elliptic function and Abel function in the generating function and obtained modified Chaplygin–Jacobi gas (MCJG) and modified Chaplygin–Abel gas (MCAG) equation of states, respectively. Next, we have assumed that the universe is filled in dark matter, radiation, and dark energy. The sources of dark energy candidates are assumed as MCJG and MCAG. We have constrained the model parameters by recent observational data analysis. Using ${\chi }^2$ minimum test (maximum likelihood estimation), we have determined the best-fit values of the model parameters by OHD$+$CMB$+$BAO$+$SNIa joint data analysis. To examine the viability of the MCJG and MCAG models, we have determined the values of the deviations of information criteria like △AIC, △BIC and △DIC. The evolutions of cosmological and cosmographical parameters (like equation of state, deceleration, jerk, snap, lerk, statefinder, Om diagnostic) have been studied for our best-fit values of model parameters. To check the classical stability of the models, we have examined the values of square speed of sound $v_s^2$ in the interval $(0,1)$ for expansion of the universe.

The physical meaning of the parameters (κ, ζ), emerging in the statistical theory [G. Kaniadakis, Eur. Phys. J. B70 (2009) 3; D. P. Mittal, Metrika22 (1975) 35; B. D. Sharma and I. J. Taneja, Metrika22 (1975) 205] considered by Kaniadakis, is explained by considering the (κ, ζ)-kinetics of a particle system, in presence of an external force field F. By using the method [J. L. Du, Phys. Lett. A329 (2004) 262] developed by Du, we show: First, the external force field necessarily induces in the system a temperature gradient ∇T. Second, the parameters (κ, ζ) are univocally related to the magnitude and the angular separation of the vectors F and ∇T. The achievements of the present paper have a general validity, holding independently on the particular approximation used to describe the collision term, in the equation governing the system evolution (i.e. Boltzmann or Fokker–Planck kinetics).

This study evaluates the Brazilian agricultural commodities market and the dollar–real exchange price variation using the multifractal detrended fluctuations analysis methodology. We investigated the period from January 1, 2019 to September 25, 2019, outside the COVID-19 pandemic, and from January 1, 2020 to September 25, 2020, during the COVID-19 pandemic. We verified the fluctuations of commodities and dollar–real exchange prices during the pandemic caused by COVID-19 showed a record price. The results of Hurst exponent and multifractal parameters ${\alpha }_0$, $w$, and $r$ indicate that during the COVID-19 pandemic, sugar was the most efficient commodity, while pork the less one. Compared to the identical months in 2019, the dollar–real exchange was the most efficient market, while ethanol was the least efficient.

In this paper, we present certain algorithms for clustering the vertices of fuzzy graphs(FGs) and intuitionistic fuzzy graphs(IFGs). These algorithms are based on the edge density of the given graph. We apply the algorithms to practical problems to derive the most prominent cluster among them. We also introduce parameters for intuitionistic fuzzy graphs.

The nanocrystalline nickel coating was synthesized by pulse-jet electrodeposition from modified Watts bath. Pulse and jet plating was employed to increase the deposition current density, decrease diffusion layer, increase the nucleation rate and in this case the prepared method would result in fine-grained deposits. Transmission and scanning electron microscopy and X-ray diffraction (XRD) were used to study the microstructure, the surface morphology, the crystal preferred orientation and the variety of the lattice parameter respectively. The influence of pulse parameters, namely peak current density, the duty cycle and pulse frequency on the grain size, surface morphology, crystal orientation and microstructure was studied. The results showed that with increasing peak current density, the deposit grain size was found to decrease markedly in other parameters at constant. However, in our experiment it was found that the grain size increased slightly with increasing pulse frequency. For higher peak current density, the surface morphology was smoother. The crystal orientation progressively changed from an almost random distribution to a strong (111) texture. This means that the peak current density was the dominated parameter to effect the microstructure of electrodeposited nanocrystalline nickel coating. In addition, the lattice parameter for the deposited nickel is calculated from XRD and it is found that the calculated value is less than the lattice parameter for the perfect nickel single crystal. This phenomenon is explained by the crystal lattice mismatch.

Pulsed laser deposition (PLD), which is a novel technique in producing thin films in the recent years, shows unique advantages for the deposition of ferroelectric films. Effects of technical parameters on the pulsed laser deposited ferroelectric films, including substrate temperature, oxygen pressure, post-annealing, buffer layer, target composition, energy density, wavelength, target-to-substrate distance, and laser pulse rate, are systematically reviewed in order to optimize these parameters. Processing-microstructure-property relationships of ferroelectric films by PLD are discussed. The application prospect is pointed as well.

As the most favorable technology, plasma spray has been used to produce the hydroxyapatite (HA) coatings with the desired phase, high crystallinity, adequate porosity, and good biocompatibility. The characteristics of the HA coating are affected by many variables of the fabricating process, such as the starting particle size, spraying distance, gas flow rate, and electric arc power, etc. This paper reviews the effect of the plasma spraying parameters on the morphology and microstructure of the HA coating, and introduces several typical HA coatings fabricated with different plasma spraying parameters.

This paper has summarized five surface strengthening methods, and these methods could to improve the surface properties of materials. The selection of mechanical parts materials has determined according to their working conditions. The work-piece in using cannot avoid defects in the material. This paper has introduced surface deformation enhancement, surface phase transformation enhancement, ion implantation technology, surface diffusion and infiltration technology, chemical transformation technology and surface coating technology. And has also included the principle of every surface technology, various technologies, parameters, strengthening characteristics, as well as strengthening effect and matters needing attention. The hardness, residual stress and corrosion resistance off mechanical parts could be improved through these surface strengthening methods. It is convenient to find the strengthening method and parameters in this paper when strengthening mechanical parts.

Inventory models are quite important when it comes to analyzing scenarios that occur in a variety of areas, including food, warehouses, vegetable markets, and other similar places. Within the scope of this study, we investigate both a linear and a nonlinear time-dependent inventory control model for things that are deteriorating. When it comes to conducting business in the modern day, the relationship that exists between retailers and customers is absolutely necessary for successful implementation. Consumers engage in commercial transactions with retailers in order to buy goods with the intention of increasing their earnings. The goal of this study is to calculate the number of times demand orders are placed by customers throughout the rotation time in order to achieve the highest possible overall profit for both the client and the merchant, both with and without the use of collaboration. In addition, it intends to investigate the disparity between the total profit obtained by the customer and the merchant in two different scenarios. Using analytical methods, the proposed model is evaluated in order to obtain the best possible solution to the problem. In the following section, a numerical example and a comparison study are discussed. Ultimately, a sensitivity analysis of the parameters is to be done to investigate the variations in the results of various parameters inside the model based on the optimal strategy.

The evaporation residue cross section of synthesizing superheavy elements requires touching probability, formation probability and survival probability. Survival probability and evaporation residue cross section appear in the last stage of synthesizing superheavy element. There are many uncertain parameters in each stage, here we focused on uncertain parameter in the survival probability that has also affect the evaporation residue cross section. As the parameters change, the calculation results also change. To adjust these parameters to fit with experiment value, we adopt the covariance method to arrange it more mathematically. There are also many possible systems for the same element especially the element that has not been discovered yet.

In this chapter, the anomalous behavior of the radon data generated in a soil chamber is investigated by estimating an interval band using an interval-midpoint approach. Further, the mathematical formulation of radon transport from soil to buildings in an uncertain environment is also investigated. For the validation of the obtained results, we have used the deterministic results of the considered model problems and found good agreement between the results.

With more requirement for formation quality of cylindrical spinning products, the improvement for formation quality of spinning products has become a difficult problem with spinning workers. The formation quality of spinning products has much to do with the setting of process parameters. In order to set the spinning process parameters reasonably and improve the formation quality, the characteristics of spinning process parameters must be well understood.

This paper presents a tool kit of new ways of understanding fundamental physics and the relationships between parameters. The novel insights and predictions include: A self-contained consistent new Planck unit set of maximal-sized parameters from which all observed values can be compared and easily combined in equations. A self-contained consistent new Planck unit set of electroncharge-based parameters, some of which are directly observable in experiments. The interpretation of the gravitational constant, G as a dimensionless ratio eliminates the need to test the equivalence of gravitational and inertial mass. That all parameters can be displayed in terms of only h and c for the Planck maximal-parameter set and additionally in a for the electron-charge-based set, previously considered impossible. A new dimensional analysis employed to describe parameter dimensionality and to uncover any law of nature or universal constant. That all electron-charge-based Planck parameters can be described solely in terms of ratios of R_k and K_j and so will benefit from the precision of measurement of these two parameters. That most electromagnetic parameters can be reinterpreted in terms of mechanical parameters. By adjusting currently misaligned SI units to be self-consistent and consistent with these Double-adjusted-Planck units, greater clarity will ensue.

The large space industrial building as the research object, established a two-dimensional physical model, using the CFD numerical simulation software simulate the partition effect that an air curtain to indoor pollutants, and analyzed the different exhaust form and air curtain's parameters such as the width, air supply velocity to the influence of the partition effect that an air curtain to indoor pollutions. The results show that the appropriate air curtain's width and air supply velocity will play the important role of good partition to indoor pollutants. When the width of the air curtain is too narrow, it will not good for the partition effect, but when the width is too wide, it is not economic; on the other hand, when the velocity of the air curtain is too big or too small, it also can't have better partition effect. From the perspective of indoor environment protection and energy saving, the air curtain is used in the indoor environment control and research out of the optimal parameters of an air curtain for good partition effect will be of great significance.

According to current shrinkage prediction mode, four kinds of concrete shrinkage prediction models (CEB-FIP 90, ACI 209 (92), RILEM B3 and GL2000) are selected to analyze in this paper. Based on the same shrinkage conditions, some important parameters of four shrinkage modes are analyzed and regular pattern of shrinkage are summarized.