Search

We consider a model of population growth based on the stochastic variation of the population size-controlled duplication of bacterial cells. It is shown that the proper choice of the control function allows for reproducing a variety of regimes: a logistic growth with saturation, a hindered growth typical for persistent bacterial systems, and a linear population growth detected for some mycobacterial populations. When supplied with the rectangular function having the width equal to the generation time, this approach represents the solution generalizing Rubinow's age-maturity model reproducing systems with desynchronization and saturation. The model's plausibility is confirmed by the direct comparison with real data for the growth of M. tuberculosis populations obtained with the BACTEC MGIT system under different conditions of growth synchronization. • A model of stochastic growth controlled by the population size. • Reproducing saturated and hundred grows by the choice of the control Functions. • Quantitative correspondence to different modes of mycobacterial population growth. [ABSTRACT FROM AUTHOR]

Presented here is a comprehensive study on the antioxidant properties of various alcoholic beverages: beers, wines, tinctures, and strong spirits, including whisky, brandy, cognac, vodkas, and liquors. The Trolox equivalent antioxidant capacity (TEAC) of each of these various alcoholic beverages is determined using an electron paramagnetic resonance (EPR) method, which is based on a semiempirical correlation. Moreover, the EC50parameter was determined on the basis of the dependences of the TEAC values obtained by this mathematical equation. Moreover, the total phenolic content (TP) and color index, which have a direct influence on the antioxidant properties of the alcoholic beverages, were identified. The results showed that all the investigated alcoholic beverages (ABs), with the exception for vodkas, exhibit antioxidant properties. By performing a statistical analysis, it was found that the TEAC value significantly depends on the TP, production method, and raw material from which the alcohol was made. However, it is assumed that the TEAC value of alcoholic beverages is independent of the alcohol content.

This study reports the atmospheric pressure viscosity data of liquid 1-iodopropane, 1-iodobutane, 1-iodopentane, 1-iodooctane, 1-iodononane, 1-iododecane, and 1-iodododecane along with relevant densities of the last five homologues from 253.15 to 423.24 K. It is demonstrated that the atmospheric pressure viscosities of 1-chloroalkanes and 1-iodoalkanes are similar to the (n+ 3) and (n+ 6) n-alkanes, respectively. At the same time, although the packing fractions of 1-chloroalkanes are most probably similar to the pertinent n-alkanes, in the case of 1-iodoalkanes, such parallels seem to be questionable. Apparently, the latter could explain a success of the entirely predictive modeling framework coupling CP-PC-SAFT with modified Yarranton–Satyro correlation (MYS) [Ind. Eng. Chem. Res.2015,54,6999] in estimating the viscosities of 1-chloroalkanes with the recommended values of critical constants and a desirability of optimizing the experimentally unavailable Tcand Pc, in cases of 1-iodopropane and further homologues. Besides that, the elevated pressure viscosities of iodoethane exhibit a substantially weaker pressure dependence than the equivalent data of n-octane, which is truthfully predicted by CP-PC-SAFT + MYS. In addition, the residual entropy-based approach of Novak [Int. J. Chem. React. Eng.2011,9,A107] predicts the viscosities of both 1-chloroalkanes and 1-iodoalkanes in the less reliable manner than CP-PC-SAFT + MYS. From the fragmental experimental data, an extent of phase splits in the binary systems of 1-iodoalkanes is wider than in the pertinent mixtures of (n+ 6) n-alkanes, which is also predicted by CP-PC-SAFT in a reliable manner.

This study reports experimental density and sound velocity data of 1-chloroheptane and 1-iodoheptane at 291.45 ≤ T≤ 413.15 K and 1 ≤ P≤ 1961 bar along with the atmospheric pressure liquid densities at 223.15 ≤ T≤ 423.10 K, sound velocities at 216.08 ≤ T≤ 413.15 K, and isobaric heat capacities at 223.15 ≤ T≤ 423.15 K. The evaluated values of the auxiliary thermodynamic properties are provided as well. An analysis performed in this study is based on the entire available high-pressure database of the medium chain 1-alkyl halides. It is demonstrated that, within its applicability range, the fluctuation theory based Tait-like equation of state (FT-EOS) predicts the high-pressure experimental data in a particularly accurate manner. The performance of the critical point based perturbed chain statistical association fluid theory (CP-PC-SAFT) is dependent on the robustness of the Tcand Pcdata, whose appropriate values allow reliable predictions of densities until extremely high pressures, sound velocities, heat capacities, and the available binary high-pressure phase equilibria data. The entirely predictive CP-PC-SAFT + MYS (modified Yarranton–Satyro correlation) modeling framework yields reliable viscosity estimations of 1-alkyl chlorides and their mixtures. At the same time, it accurately predicts the pressure dependence established by the viscosity of 1-bromobutane only up to ∼2000 bar and it tends to underestimate this property for 1-iodoalkanes. Investigation of trends established by CP-PC-SAFT allows making some essential assumptions about the regularities characteristic for thermophysical properties of 1-alkyl halides at elevated pressures.

We report the raw data of the density and the speed of sound obtained by acoustic piezometer in previously unexplored range of temperatures, which exceed the boiling point of 2-chloropropane, starting from the saturation curve and extended into single phase region under high pressures. The fits of the obtained data are given.

The fluctuation theory equation of state has been applied to the class of chemicals used for lubrication in extreme conditions ranging from the cold vacuum of outer space to the high pressure and high temperatures of deep oil wells. The predictions made by this equation agree very well with the experimental data considering the input data include only temperature-dependent density and isothermal compressibility at atmospheric pressure to predict the high-pressure and high-temperature densities. The densities of a total of 56 different oils were analyzed with this equation up to a temperature of 533 K and pressure of 1 GPa. The range of deviation for the measured samples is from 0.01% to 4.31%, and the physical basis for this deviation is discussed.

The paper analyses a possibility of utilising the information which is contained in DIPPR database for a calculation of the speed of sound, which is absent there. As an example, liquid hydrocarbons are considered: n-hexane, 1-hexene, cyclohexane, cyclohexene, benzene, and 1-hexanols, as well as representatives of n-alkanes with various hydrocarbon chain lengths. It is shown that the Brelvi-O’Connell correlation for the reduced bulk modulus, supplied with the correlations for the internal pressure at the normal boiling temperature, results in the values having accuracy comparable with other DIPPR data for the region below the boiling point bounded by the values of the reduced density around ρr≈ 3.5. The source of errors originated from the Brelvi-O’Connell correlation for larger reduced densities is discussed.

We comment on work by Daridon et al., who proposed a novel method for computing the isobaric thermal expansion coefficient with the use of Mosteller–Tukey linearization of the density as a function of temperature. Since the mentioned work was primarily focused on the data at the standard atmospheric pressure and temperatures below the boiling point, we explore the range of validity of this approach in a more wide range of pressures and temperatures with special attention to the reproducibility of the zero temperature derivative of the expansivity at high pressures. It was found that the Daridon et al.’s method provides an accurate representation of the thermal expansion isobars in the subcritical temperature region up to the temperature where the real dependence has an inflection point. This means that the respective functional form can neither reproduce a finite maximum in the expansivity at supercritical pressures nor the divergence at the critical point. At the same time, within the method’s range of applicability, it allows detecting accurately the location of the points corresponding to the crossing of the thermal expansion isotherms that is demonstrated using the density data as well as the direct measurement of the expansivity through scanning transitiometry.

Abstract: We consider the process of an epidemic spread in a population of individuals with low mobility within the SIR scheme. In a continuum limit such propagation mechanism is described by a non-linear reaction–diffusion equation with a diffusion coefficient being the function of the densities of susceptible. The traveling wave solution of the corresponding system of partial differential equations is obtained and analyzed. We show that the model allows for description of Kendall epidemic waves, and give the dependence of the infection wave’s shape on the parameters of the system. An explicit calculation is done for realistic values of parameters obtained from field epidemiological data for a phocine distemper virus infection among harbor seals in 1988. [Copyright &y& Elsevier]

We report the data of the density and the speed of sound for 3-chloroheptane at ambient conditions and under elevated pressures. The results obtained argue in favour of one of two known sets of density data at ambient pressures and significantly expand the temperature range of measurements. The data obtained at elevated pressures are the first experimental dataset reported for this liquid. The fits of the obtained data are provided.

• COVID-19. • SIR-model reducible to logistic regression. • Forecast uncertainty quantification. • Revealing effect of epidemic prevention measures. Basing on existence of the mathematically sequential reduction of the three-compartmental (Susceptible-Infected-Recovered/Removed) model to the Verhulst (logistic) equation with the parameters determined by the basic characteristic of epidemic process, this model is tested in application to the recent data on COVID-19 outbreak reported by the European Centre for Disease Prevention and Control. It is shown that such a simple model adequately reproduces the epidemic dynamics not only qualitatively but for a number of countries quantitatively with a high degree of correlation that allows to use it for predictive estimations. In addition, some features of SIR model are discussed in the context, how its parameters and conditions reflect measures attempted for the disease growth prevention that is also clearly indicated by deviations from such model solutions. [ABSTRACT FROM AUTHOR]