On the nonlocal viscosity kernel of mixtures

In this report we investigate the multiscale hydrodynamical response of a liquid as a function of mixture composition. This is done via a series of molecular dynamics simulations where the wave vector dependent viscosity kernel is computed for three mixtures each with 7-15 different compositions. We observe that the nonlocal viscosity kernel is dependent on composition for simple atomic mixtures for all the wave vectors studied here, however, for a model polymer melt mixture the kernel is independent of composition for large wave vectors. The deviation from ideal mixing is also studied. Here it is shown that a Lennard-Jones mixture follows the ideal mixing rule surprisingly well for a large range of wave vectors, whereas for both the Kob-Andersen mixture and the polymer melt large deviations are found. Furthermore, for the polymer melt the deviation is wave vector dependent such that there exists a critical length scale at which the ideal mixing goes from under-estimating to over-estimating the viscosity

Person-Affecting Paretian Egalitarianism with Variable Population Size

http://web.missouri.edu/~klinechair/on-line%20papers/person-affecting%20APE.docWhere there is a fixed population (i.e., who exists does not depend on what choice an agent makes), the deontic version of anonymous Paretian egalitarianism holds that an option is just if and only if (1) it is anonymously Pareto optimal (i.e., no feasible alternative has a permutation that is Pareto superior), and (2) it is no less equal than any other anonymously Pareto optimal option. We shall develop and discuss a version of this approach for the variable population case (i.e., where who exists does depend on what choice an agent makes). More specifically, we shall develop and discuss it in the context of a person-affecting framework—in which an option is just if and only if it wrongs no one according to certain plausible conditions on wronging

Correlations in Nuclear Arrhenius-Type Plots

Arrhenius-type plots for multifragmentation process, defined as the transverse energy dependence of the single-fragment emission-probability, -ln(p_{b}) vs 1/sqrt(E_{t}), have been studied by examining the relationship of the parameters p_{b} and E_{t} to the intermediate-mass fragment multiplicity . The linearity of these plots reflects the correlation of the fragment multiplicity with the transverse energy. These plots may not provide thermal scaling information about fragment production as previously suggested.Comment: 12 pages, Latex, 3 Postscript figures include

Falsification Of The Atmospheric CO2 Greenhouse Effects Within The Frame Of Physics

The atmospheric greenhouse effect, an idea that many authors trace back to the traditional works of Fourier (1824), Tyndall (1861), and Arrhenius (1896), and which is still supported in global climatology, essentially describes a fictitious mechanism, in which a planetary atmosphere acts as a heat pump driven by an environment that is radiatively interacting with but radiatively equilibrated to the atmospheric system. According to the second law of thermodynamics such a planetary machine can never exist. Nevertheless, in almost all texts of global climatology and in a widespread secondary literature it is taken for granted that such mechanism is real and stands on a firm scientific foundation. In this paper the popular conjecture is analyzed and the underlying physical principles are clarified. By showing that (a) there are no common physical laws between the warming phenomenon in glass houses and the fictitious atmospheric greenhouse effects, (b) there are no calculations to determine an average surface temperature of a planet, (c) the frequently mentioned difference of 33 degrees Celsius is a meaningless number calculated wrongly, (d) the formulas of cavity radiation are used inappropriately, (e) the assumption of a radiative balance is unphysical, (f) thermal conductivity and friction must not be set to zero, the atmospheric greenhouse conjecture is falsified.Comment: 115 pages, 32 figures, 13 tables (some typos corrected

Effects of boundary conditions on magnetization switching in kinetic Ising models of nanoscale ferromagnets

Magnetization switching in highly anisotropic single-domain ferromagnets has been previously shown to be qualitatively described by the droplet theory of metastable decay and simulations of two-dimensional kinetic Ising systems with periodic boundary conditions. In this article we consider the effects of boundary conditions on the switching phenomena. A rich range of behaviors is predicted by droplet theory: the specific mechanism by which switching occurs depends on the structure of the boundary, the particle size, the temperature, and the strength of the applied field. The theory predicts the existence of a peak in the switching field as a function of system size in both systems with periodic boundary conditions and in systems with boundaries. The size of the peak is strongly dependent on the boundary effects. It is generally reduced by open boundary conditions, and in some cases it disappears if the boundaries are too favorable towards nucleation. However, we also demonstrate conditions under which the peak remains discernible. This peak arises as a purely dynamic effect and is not related to the possible existence of multiple domains. We illustrate the predictions of droplet theory by Monte Carlo simulations of two-dimensional Ising systems with various system shapes and boundary conditions.Comment: RevTex, 48 pages, 13 figure

Ground Forces Impact on Release of Rotational Shot Put Technique

In the shot put throw, the primary power is generated in the form of ground reaction forces as a result of action of the lower extremities (Coh, Stuhec, & Supej, 2008). The purpose of this study was to determine how the ground reaction force and ground contact time during the delivery phase of rotational shot put relates to the predicted distance of the throw. This will allow us to determine the optimal approach of force application for maximum throwing distance (Linthorne, 2001). Eight male subjects were used in this study (age 23 ± 4 y; body mass 123 ± 14 kg; height 190 ± 4 cm; all right handed). Subjects threw three attempts in a custom-built shot put ring where two force plates were located where both feet were expected to land in the delivery. The throws were also filmed using two high-speed cameras at 120 frames/s. These videos gave us the speed, angle and height of release for predicting distance thrown. Results: Peak right leg force during delivery was correlated with throwing distance (R2 = 0.450, p = 0.001). Also, left leg ground time was significant with predicted throwing distance (R² = 0.516, p \u3c 0.001). Because increased strength leads to greater throwing distances (Zaras et al., 2013) and peak right leg force was significant, it would be useful to perform proper strength training exercises that can increase a thrower\u27s ability to increase the peak ground forces during a throw. If the thrower can produce greater peak force into the ground with the right leg during the delivery phase, this should cause the thrower to come off their left leg sooner, resulting in greater speed of release and thus distance thrown

Magnetism, FeS colloids, and Origins of Life

A number of features of living systems: reversible interactions and weak bonds underlying motor-dynamics; gel-sol transitions; cellular connected fractal organization; asymmetry in interactions and organization; quantum coherent phenomena; to name some, can have a natural accounting via $physical$ interactions, which we therefore seek to incorporate by expanding the horizons of `chemistry-only' approaches to the origins of life. It is suggested that the magnetic 'face' of the minerals from the inorganic world, recognized to have played a pivotal role in initiating Life, may throw light on some of these issues. A magnetic environment in the form of rocks in the Hadean Ocean could have enabled the accretion and therefore an ordered confinement of super-paramagnetic colloids within a structured phase. A moderate H-field can help magnetic nano-particles to not only overcome thermal fluctuations but also harness them. Such controlled dynamics brings in the possibility of accessing quantum effects, which together with frustrations in magnetic ordering and hysteresis (a natural mechanism for a primitive memory) could throw light on the birth of biological information which, as Abel argues, requires a combination of order and complexity. This scenario gains strength from observations of scale-free framboidal forms of the greigite mineral, with a magnetic basis of assembly. And greigite's metabolic potential plays a key role in the mound scenario of Russell and coworkers-an expansion of which is suggested for including magnetism.Comment: 42 pages, 5 figures, to be published in A.R. Memorial volume, Ed Krishnaswami Alladi, Springer 201

Solubility of Rock in Steam Atmospheres of Planets

Extensive experimental studies show that all major rock-forming elements (e.g., Si, Mg, Fe, Ca, Al, Na, K) dissolve in steam to a greater or lesser extent. We use these results to compute chemical equilibrium abundances of rocky-element-bearing gases in steam atmospheres equilibrated with silicate magma oceans. Rocky elements partition into steam atmospheres as volatile hydroxide gases (e.g., Si(OH)4, Mg(OH)2, Fe(OH)2, Ni(OH)2, Al(OH)3, Ca(OH)2, NaOH, KOH) and via reaction with HF and HCl as volatile halide gases (e.g., NaCl, KCl, CaFOH, CaClOH, FAl(OH)2) in much larger amounts than expected from their vapor pressures over volatile-free solid or molten rock at high temperatures expected for steam atmospheres on the early Earth and hot rocky exoplanets. We quantitatively compute the extent of fractional vaporization by defining gas/magma distribution coefficients and show that Earth's subsolar Si/Mg ratio may be due to loss of a primordial steam atmosphere. We conclude that hot rocky exoplanets that are undergoing or have undergone escape of steam-bearing atmospheres may experience fractional vaporization and loss of Si, Mg, Fe, Ni, Al, Ca, Na, and K. This loss can modify their bulk composition, density, heat balance, and interior structure

Barley grain at Uppåkra, Sweden: evidence for selection in the Iron Age

A metric analysis on hulled barley grain from the Iron Age regional centre of Uppåkra and surrounding sites in southern Sweden has identified a variation in the size of the grain found on these archaeological sites. Large, high-quality grain was found more frequently at Uppåkra when compared to sites in the surrounding area, where smaller grain was more frequent. The observed large grain found at Uppåkra was, however, restricted to only a few house contexts, including hall-buildings, while other contexts on the site, such as areas dedicated to craft production, had barley assemblages containing smaller grain, similar to the size range found on the surrounding sites. The intra-site variation between different contexts at Uppåkra points to a degree of sorting for larger grain and that this variation between grain assemblages was the result of selection after the crop processing was completed. The distribution of grain size at Uppåkra shows a pattern that indicates that the high-quality barley grain was indented for specific individuals or households. The different contexts at Uppåkra have together produced a record spanning the first millennium ad, representing almost the whole existence of the site. The evidence for selection of larger grain can be seen in the hall-buildings throughout most of the first millennium ad, although less prominently during the Late Roman Iron Age (ad 200–400), while during the Migration Period (ad 400–550) several houses on the main site Uppåkra had assemblages of large grain size. The distribution of grain size at the regional centre Uppåkra shows a pattern that indicates that the handling of large high-quality barley grain was part of a spatial organization, and such organization is similar to other functions observed on the site. The long-term record of grain size patterns across time shows that a structure for handling grain was already in place during the early phase of the settlement and that it remained for centuries. This study indicates that the affluence otherwise seen at the regional centre Uppåkra from an abundance of high-status objects, could also include agricultural wealth, with extensive access to high-quality grain