Liquid mixtures involving fluorinated alcohols: The equation of state (p, r, T, x) of (Ethanol + Trifluoroethanol) Experimental and Simulation

Liquid mixtures involving fluorinated alcohols: The equation of state (p, r, T, x) of (Ethanol + Trifluoroethanol) Experimental and Simulation Pedro Duartea, Djêide Rodriguesa, Marcelo Silvaa, Pedro Morgadoa, Luís Martinsa,b and Eduardo J. M. Filipea* aCentro de Química Estrutural, Instituto Superior Técnico, 1049-001 Lisboa, Portugal bCentro de Química de Évora, Universidade de Évora, 7000-671 Évora, Portugal Fluorinated alcohols are substances with unique properties and high technological value in the pharmaceutical and chemical industries. Trifluoroethanol (TFE), in particular, displays a number of unusual properties as a solvent. For example, it dissolves nylon at room temperature and is effectively used as solvent in bioengineering. The presence of the three fluorines atoms gives the alcohol a high ionization constant, strong hydrogen bonding capability and stability at high temperatures. In the pharmaceutical industry, TFE finds use as the major raw material for the production of inhalation anesthetics. Mixtures of TFE and water (known as Fluorinols®) are used as working fluids for Rankine cycle heat engines for terrestrial and space applications, as a result of a unique combination of physical and thermodynamic properties such as high thermal efficiency and excellent turbine expansion characteristics. Environmentally, TFE is a CFC substitute with an acceptable short lifetime and with small ozone depletion potential. Additionally, TFE is known to induce conformational changes in proteins and it is used as a co-solvent to analyze structural features of partially folded states. The (ethanol + TFE) system displays an interesting and peculiar behaviour, combining a negative azeotrope with high positive excess volumes. In this work, liquid mixtures of (ethanol + TFE) were investigated. The densities of the mixtures were measured as a function of composition between 278K and 338K and at pressures up to 700 bar. The corresponding excess volumes as a function of temperature and pressure, the isothermal compressibilities and thermal expansivities were calculated from the experimental results. The mixtures are highly non-ideal with excess volumes ranging from 0.8 - 1.0 cm3mol-1. Finally, molecular dynamic simulations were performed to model and interpret the experimental results. The Trappe force field was used to simulate the (TFE + ethanol) mixtures and calculate the corresponding excess volumes. The simulation results are able to reproduce the correct sign and order of magnitude of the experimental VE without fitting to the experimental data. Furthermore, the simulations suggest the presence of a particular type of hydrogen bridge between ethanol and TFE, that can help to rationalize the experimental results

On the distribution of high-frequency stock market traded volume: a dynamical scenario

This manuscript reports a stochastic dynamical scenario whose associated stationary probability density function is exactly a previously proposed one to adjust high-frequency traded volume distributions. This dynamical conjecture, physically connected to superstatiscs, which is intimately related with the current nonextensive statistical mechanics framework, is based on the idea of local fluctuations in the mean traded volume associated to financial markets agents herding behaviour. The corroboration of this mesoscopic model is done by modelising NASDAQ 1 and 2 minute stock market traded volume

Radiolysis of ammonia-containing ices by energetic, heavy and highly charged ions inside dense astrophysical environments

Deeply inside dense molecular clouds and protostellar disks, the interstellar ices are protected from stellar energetic UV photons. However, X-rays and energetic cosmic rays can penetrate inside these regions triggering chemical reactions, molecular dissociation and evaporation processes. We present experimental studies on the interaction of heavy, highly charged and energetic ions (46 MeV Ni^13+) with ammonia-containing ices in an attempt to simulate the physical chemistry induced by heavy ion cosmic rays inside dense astrophysical environments. The measurements were performed inside a high vacuum chamber coupled to the heavy ion accelerator GANIL (Grand Accelerateur National d'Ions Lourds) in Caen, France.\textit{In-situ} analysis is performed by a Fourier transform infrared spectrometer (FTIR) at different fluences. The averaged values for the dissociation cross section of water, ammonia and carbon monoxide due to heavy cosmic ray ion analogs are ~2x10^{-13}, 1.4x10^{-13} and 1.9x10^{-13} cm$^2$, respectively. In the presence of a typical heavy cosmic ray field, the estimated half life for the studied species is 2-3x10^6 years. The ice compaction (micropore collapse) due to heavy cosmic rays seems to be at least 3 orders of magnitude higher than the one promoted by (0.8 MeV) protons . In the case of the irradiated H2O:NH3:CO ice, the infrared spectrum at room temperature reveals five bands that were tentatively assigned to vibration modes of the zwitterionic glycine (+NH3CH2COO-).Comment: Accepted to be published in Astronomy and Astrophysics; Number of pages: 12; Number of Figures: 7; Number of Tables:

A Method to Tackle First Order Differential Equations with Liouvillian Functions in the Solution - II

We present a semi-decision procedure to tackle first order differential equations, with Liouvillian functions in the solution (LFOODEs). As in the case of the Prelle-Singer procedure, this method is based on the knowledge of the integrating factor structure.Comment: 11 pages, late

O impacto da liderança e do contexto organizacional na aceitabilidade ética de práticas de Gestão de Recursos Humanos

Recent research has found that human resource (HR) practitioners judge the acceptability of ethically questionable practices based on the importance their organization attributes to specific features: ethical infrastructure (e.g., codes of conduct) and corporate social responsibility (CSR) practices. The present study sought to evaluate the effects of ethical leadership and the aforementioned features on other non-HR organizational actors. More specifically, this research examined how these individuals judge the acceptability of three ethically dubious HR management (HRM) practices: discrimination, disregard for the individual, and favor shown to those in power. Results obtained for data collected through an online survey indicate that ethical leadership is negatively associated with the acceptability of all three practices. Individuals in organizations with a strong ethical infrastructure also find discrimination and a disregard for the individual less acceptable. The same is true of participants in organizations perceived as more socially responsible regarding employees and economic aspects.info:eu-repo/semantics/publishedVersio