Nonequilibrium Experiment Research Articles

More movement with manure: increased mobility of erythromycin through agricultural soil in the presence of manure.

Antibiotic residues in the environment threaten soil and aquatic organisms and human and livestock health through the building of antimicrobial resistance. Manure spreading associated with animal agriculture is one source of environmental antibiotic residues. To better understand the risk of contamination, we studied the adsorption of erythromycin, a model macrolide antibiotic used across human and animal medicine. We conducted a series of equilibrium batch experiments to determine the kinetics and extent of adsorption and a continuous-flow column adsorption experiment to observe non-equilibrium adsorption patterns. We determined that the adsorption equilibration time to soil was approximately 72 h in our batch experiments. Erythromycin adsorbed to soil relatively strongly (K = 8.01 × 10-2 L/mg; qmax = 1.53 × 10-3 mg/mg), adsorbed to the soil in the presence of manure with less affinity (K = 1.99 × 10-4 L/mg) at a soil: manure ratio of 10:1 by mass, and did not adsorb to manure across the solid ratios tested. We observed multi-phased adsorption of erythromycin to the soil during the non-equilibrium column experiment, which was largely absent from the treatments with both soil and manure present. These results suggest that erythromycin is more mobile in the environment when introduced with manure, which is likely the largest source of agriculturally sourced environmental antibiotics.

A simplified method for calculating spectral emission of nonequilibrium air plasmas in hypersonic shock-layers

A simplified method for calculating the spectral emission of nonequilibrium air plasmas is developed. In order to obtain the nonequilibrium energy level populations, the nonequilibrium coefficients are introduced into the Saha-Boltzmann equation. These nonequilibrium coefficients are calculated by using several significant radiative processes. An approach to the determination of nonequilibrium electronic energy level populations of diatomic molecules is also presented. Based on the method, spectral emission of atoms and molecules in a typical air plasma cell is investigated. The results reveal that there is a significant difference between the nonequilibrium and equilibrium emission. We apply the method to the nonequilibrium AVCO R-156 experiment. Good agreement with the NEQAIR code and the measured data is shown, indicating that the method is reasonable and has good accuracy.

RADIS: A nonequilibrium line-by-line radiative code for CO2 and HITRAN-like database species

An open-source nonequilibrium emission and absorption infrared line-by-line code is presented. RADIS is built around the HITRAN, HITEMP and CDSD databases for molecules in their electronic ground state. Energy levels are read from tabulated databases or calculated from Dunham expansions. Boltzmann, Treanor, and arbitrary vibrational distributions can be generated. In its present version, nonequilibrium spectra can be computed for CO2 and CO, and equilibrium spectra can be computed for all species of the HITRAN database. New species can be added without modification to the core code. Several optimization strategies are described that reduce computation times of high-temperature, high-resolution spectra with millions of lines down to less than a minute. Additionally, RADIS includes a line survey tool, a built-in look-up database to reduce convergence times when fitting experimental spectra, and a multi-slab module to simulate line-of-sight experiments. Validation cases against existing spectral codes and experimental results from various plasma sources are presented. Finally, RADIS is applied to improve the modeling of the radiation from a plasma torch and a nonequilibrium expansion-tube experiment. RADIS is distributed under LGPLv3 license [1].

25-75℃の皮膚およびコラーゲンの比熱推定：非定常熱伝導実験と計算

25-75℃の皮膚およびコラーゲンの比熱推定：非定常熱伝導実験と計算

Universality and criticality of a second-order granular solid-liquid-like phase transition.

We experimentally study the critical properties of the nonequilibrium solid-liquid-like transition that takes place in vibrated granular matter. The critical dynamics is characterized by the coupling of the density field with the bond-orientational order parameter Q(4), which measures the degree of local crystallization. Two setups are compared, which present the transition at different critical accelerations as a result of modifying the energy dissipation parameters. In both setups five independent critical exponents are measured, associated to different properties of Q(4): the correlation length, relaxation time, vanishing wavenumber limit (static susceptibility), the hydrodynamic regime of the pair correlation function, and the amplitude of the order parameter. The respective critical exponents agree in both setups and are given by ν(⊥)=1,ν(∥)=2,γ=1,η≈0.6-0.67, and β=1/2, whereas the dynamical critical exponent is z=ν(∥)/ν(⊥)=2. The agreement on five exponents is an exigent test for the universality of the transition. Thus, while dissipation is strictly necessary to form the crystal, the path the system undergoes toward the phase separation is part of a well-defined universality class. In fact, the local order shows critical properties while density does not. Being the later conserved, the appropriate model that couples both is model C in the Hohenberg and Halperin classification. The measured exponents are in accord with the nonequilibrium extension to model C if we assume that α, the exponent associated in equilibrium to the specific heat divergence but with no counterpart in this nonequilibrium experiment, vanishes.

Comparison of rheological properties of short-chain perfluoropolyethers through simulation and experiment

Four short-chain perfluoropolyethers (PFPEs) with varied architectural modifications have been studied rheologically using non-equilibrium molecular dynamics simulation and experiment. An explicit-atom potential, which treats all fluorine atoms equivalently, is not capable of reproducing the experimentally observed trends in viscosity among the four compounds. Rather, the parameters of the potential governing the interaction of fluorine must reflect the proximity of the fluorine to the oxygen in the ether linkage. Defining four different types of fluorine atoms, we are able to reproduce the experimentally observed trends in viscosity among the four compounds. We examine the effect of this potential change on the structural properties as well.

Ultraslow nonequilibrium dynamics in supercooled glycerol by stimulated Brillouin gain spectroscopy

We have used high resolution stimulated Brillouin gain spectroscopy to monitor the nonequilibrium relaxation dynamics of supercooled glycerol near its glass transition temperature. After a temperature quench from 192.4 to 179.8 K, the Brillouin frequency shift increased over a period of 17 d from 16.877±0.005 GHz to 17.195±0.005 GHz, the equilibrium value expected for the final temperature. The relaxation of the shift appears to proceed in three distinct stages. The first and most rapid stage tracks the time dependence of the temperature. This is followed by a slower relaxation process which is well characterized by a stretched exponential function exp[−(t/τ)β]. The values determined for τ (12±2 ks) and β (0.61±0.09) are consistent with values predicted from recent dielectric and enthalpy relaxation studies of glycerol in the same temperature range, as long as allowances are made for the nonlinear nature of the nonequilibrium experiment. The third and final stage in the relaxation is approximately exponential with a time constant of 430±40 ks. We speculate that this ultraslow process may have its origin in the relaxation of mechanical strain built up in the sample during the temperature quench, or that it could result from the nonlinear nature of the experiment and the heterogeneous nature of dynamics in supercooled liquids. A comparison with other methods (dilatometry, probe fluorescence) for studying nonequilibrium relaxation in supercooled liquids shows our technique to be comparable in sensitivity. Finally, the Brillouin linewidth showed no change after an initial rapid decrease to 18±2 MHz (half width at half maximum), indicating a lack of significant spatial heterogeneity in the physical properties and/or relaxation dynamics on length scales of the order of the acoustic wavelength (0.2 μm) or longer.

Classification theory for anequilibrium phase transitions

The paper introduces a classification of phase transitions in which each transition is characterized through its generalized order and a slowly varying function. This characterization is shown to be applicable in statistical mechanics as well as in thermodynamics albeit for different mathematical reasons. By introducing the block ensemble limit the statistical classification is based on the theory of stable laws from probability theory. The block ensemble limit combines scaling limit and thermodynamic limit. The thermodynamic classification on the other hand is based on generalizing Ehrenfest's traditional classification scheme. Both schemes imply the validity of scaling at phase transitions without the need to invoke renormalizaton-group arguments. The statistical classification scheme allows derivation of a form of finite-size scaling for the distributions of statistical averages while the thermodynamic classification gives rise to multiscaling of thermodynamic potentials. The different nature of the two classification theories is also apparent from the fact that the generalized thermodynamic order is unbounded while the statistical order is restricted to values less than 2. This fact is found to be related to the breakdown of hyperscaling relations. Both classification theories predict the possible existence of phase transitions having orders less than unity. Such transitions are termed anequilibrium transitions.Systems near anequilibrium transitions cannot be described by conventional equilibrium thermodynamics or equilibrium statistical mechanics because of very strong fluctuations. Anequilibrium transitions are found to exist in statistical-mechanical model systems. The identification of the Lagrange parameter \ensuremath{\beta} in the canonical ensemble becomes invalid if a reservoir and a system of the same substance are in thermal contact and anequilibrium transitions are present. Based on the ergodic hypothesis and the theory of convolution semigroups it is shown that near anequilibrium transitions the equations of motion for macroscopic observables of infinite systems may involve modified time derivatives as generators of the macroscopic time evolution. The general solution to the modified equations of motion exhibits very slow dynamics as frequently observed in a nonequilibrium experiment.

Stochastic theory for the glassy state. 1. Influence of formation history on the glass transition temperature and equation of state

A stochastic theory is developed to describe the influence of glass formation history on the equation of state of polymer glasses and on the glass transition temperature. The theory is based on the assumption of a spatial distribution of free volume and hence mobility in the polymer system. The free volume is identified with the order parameter h in the Holey Huggins theory. The response of the system to a change in pressure and/or temperature is formed by a change of the actual free volume distribution to the new equilibrium. All requisite parameters but one can be obtained from independent experiments on the equilibrium polymer melt. The remaining parameter is presently determined from a nonequilibrium relaxation experiment. For poly(viny1 acetate) the calculated cooling rate and pressure dependence of the glass transition temperature and the calculated dependence of the equation of state of the polymer glass on formation pressure are compared to experimental data. In general, good agreement is obtained.

Equilibrium and Nonequilibrium Partition Coefficients of Volatile Fission Products between Liquid Sodium and the Gas Phase

Two series of experiments have been conducted to obtain the gas-liquid equilibrium partition coefficient Kd and the nonequilibrium partition coefficient K’d of volatile fission products such as cesium, iodine, and tellurium between liquid sodium and the gas phase. In the equilibrium experiment, a sodium pool mixed with a fission product simulant was heated by an electric furnace, and the solvent of the vapors and aerosols trapped by filters was quantitatively analyzed. The results are as follows: 1. Cesium shows the largest Kd (20 to 100).2. The Kd value of iodine scatters as widely as 0.02 to 0.5 at 450°C and 0.3 to 0.8 at 650°C.3. The Kd values of cesium and iodine agree well with the theoretical ones reported by Castleman and Tang.4. If sodium telluride, which is harder to vaporize than pure tellurium, is assumed, the measured Kd value of tellurium agrees with the theoretical. The nonequilibrium experiment in which the temperature dropped relatively sharply in the cover-gas region shows that K’d was not larger than Kd.

Breakdown of symmetry in an exemplary turing system

Based on the well-established Rashevsky-Turing theory of morphogenesis, a two- compartment reaction-diffusion model consisting of cross-inhibitoriiy coupled, potentially oscillating two-variable subsystems (4-dimensionai flow) is reported, the dynamics of which can be described by a few coupled nonlinear ordinary differential equations. We focus on the evocation of symmetry-breaking instabilities developing from an originally symmetrical stationary state under parametric change of the diffusive coupling. The spatio-temporal correlation behaviour of the evocated system flow is analysed on the way from stable steady state towards irregularly recurring differentiation. The model ingredients are finally projected onto the dynamical possibilities of a non-equilibrium semiconductor experiment

Measurement of polydispersity of ultra‐narrow polymer fractions by thermal field‐flow fractionation

AbstractIn this paper we demonstrate that the polydispersity µ = M̄w/M̄N of narrow polymer fractions can be readily obtained by measuring band broadening and its velocity dependence in a thermal field–flow fractionation (thermal FFF) system. The thermal FFF method is shown to be more accurate than size exclusion chromatography for the determination of polymer polydispersities due to the simpler band dispersion function and the higher selectivity inherent to the technique. The polydispersities of a series of four narrow polystyrene samples prepared by anionic polymerization were consequently determined by thermal FFF and found to be much smaller (1.003–1.006) than the ceiling values (1.06) suggested by the suppliers. As part of this investigation, an experimental study of band dispersion in thermal FFF is used to examine current theory. The data show nonequilibrium to be the dominant factor, whereas relaxation effects are insignificant at lower flow rates and can be subdued at higher flow rates. A high correlation between nonequilibrium theory and experiment allows for the estimation of diffusion coefficients from plate height–velocity data.