The perception of melodic consonance: an acoustical and neurophysiological explanation based on the overtone series

The melodic consonance of a sequence of tones is explained using the overtone series: the overtones form "flow lines" that link the tones melodically; the strength of these flow lines determines the melodic consonance. This hypothesis admits of psychoacoustical and neurophysiological interpretations that fit well with the place theory of pitch perception. The hypothesis is used to create a model for how the auditory system judges melodic consonance, which is used to algorithmically construct melodic sequences of tones

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https://scholarworks.bgsu.edu/arfp/1016/thumbnail.jp

Characterizing Ionic Liquids On the Basis of Multiple Solvation Interactions

Room-temperature ionic liquids (RTILs) are useful in many chemical applications. Recent publications have attempted to determine the polarity of RTILs using empirical solvent polarity scales. The results have indicated that most RTILs have similar polarities. Nevertheless, RTILs are capable of behaving quite differently when used as solvents in organic synthesis, matrixes in matrix-assisted laser desorption/ionization (MALDI) mass spectrometry, liquid−liquid extraction, and as stationary phases in gas chromatography. The work presented in this study uses a linear free energy approach to characterize 17 RTILs on the basis of their distinct multiple solvation interactions with probe solute molecules. This model provides data that can be used to help identify the interactions and properties that are important for specific chemical applications

Structure and Properties of High Stability Geminal Dicationic Ionic Liquids

Thirty-nine geminal dicationic ILs were synthesized and characterized in terms of their surface tensions, densities, melting points, refractive indices, viscosities, and miscibilities with a polar and nonpolar solvent. Two imidazolium or pyrrolidinium cations were joined via different length hydrocarbon linkage chains (from 3 to 12 carbons long). The various geminal dications were paired with up to four different anions. The effect of the dication type, linkage chain, alkyl substituents, and anion type on the physicochemical properties of these compounds was examined. Among the more interesting findings for this class of compounds was that their liquid and thermal stability ranges generally exceeded those of the more conventional, better known ILs. Indeed, this range was from −4 to \u3e400 °C for one of the pyrrolidinium-based geminal dicationic liquids. X-ray crystallography of the smaller solid ionic compounds indicated that there may be a correlation between the configurational degrees of freedom of the ILs and their melting points/glass transition temperatures. In one case, the crystal structure showed that a dicationic moiety had three distinct conformations in an asymmetric unit cell. The solvation properties of the geminal dicationic ILs tend to be similar to those of their monocationic analogues

A Polytope Combinatorics for Semisimple Groups

Mirkovi and Vilonen discovered a canonical basis of algebraic cycles for the intersection homology of (the closures of the strata of) the loop Grassmannian. The moment map images of these varieties are a collection of polytopes, and they may be used to compute weight multiplicities and tensor product multiplicities for representations of a semisimple group. The polytopes are explicitly described for a few low rank groups

Tunable Silver-containing Stationary Phases for Multidimensional Gas Chromatography

To achieve high separation power of complex samples using multidimensional gas chromatography (MDGC), the selectivity of the employed stationary phases is crucial. The non-polar × polar column combination remains the most popular column set used in MDGC. However, resolution of mixtures containing light analytes possessing very similar properties remains a formidable challenge. The development of stationary phases that offer unique separation mechanisms have the potential to significantly improve MDGC separations, particularly in resolving co-eluted peaks in complex samples. For the first time, a stationary phase containing silver(I) ions was successfully designed and employed as a second dimension column using comprehensive two dimensional gas chromatography (GC × GC) for the separation of mixtures containing alkynes, dienes, terpenes, esters, aldehydes, and ketones. Compared to a widely used non-polar and polar column set, the silver-based column exhibited superior performance by providing better chromatographic resolution of co-eluted compounds. A mixture of unsaturated fatty acids was successfully separated using a GC × GC method in which the elution order in the second dimension was highly dependent on the number of double bonds within the sample

Theory and Use of the Pseudophase Model in Gas−Liquid Chromatographic Enantiomeric Separations

The theory and use of the “three-phase” model in enantioselective gas−liquid chromatography utilizing a methylated cyclodextrin/polysiloxane stationary phase is presented for the first time. Equations are derived that account for all three partition equilibria in the system, including partitioning between the gas mobile phase and both stationary-phase components and the analyte equilibrium between the polysiloxane and cyclodextrin pseudophase. The separation of the retention contributions from the achiral and chiral parts of the stationary phase can be easily accomplished. Also, it allows the direct examination of the two contributions to enantioselctivity, i.e., that which occurs completely in the liquid stationary phase versus the direct transfer of the chiral analyte in the gas phase to the dissolved chiral selector. Six compounds were studied to verify the model:  1-phenylethanol, α-ionone, 3-methyl-1-indanone, o-(chloromethyl)phenyl sulfoxide, o-(bromomethyl)phenyl sulfoxide, and ethyl p-tolylsulfonate. Generally, the cyclodextrin component of the stationary phase contributes to retention more than the bulk liquid polysiloxane. This may be an important requirement for effective GC chiral stationary phases. In addition, the roles of enthalpy and entropy toward enantiorecognition by this stationary phase were examined. While enantiomeric differences in both enthalpy and entropy provide chiral discrimination, the contribution of entropy appears to be more significant in this regard. The three-phase model may be applied to any gas−liquid chromatography stationary phase involving a pseudophase

Investigating the effect of ligand and cation on the properties of metal fluorinated acetylacetonate based magnetic ionic liquids

Magnetic ionic liquids (MILs) are a subclass of ionic liquids that possess a paramagnetic metal within their chemical structure, making them susceptible to external magnetic fields. A total of twenty-four (24) MILs were prepared and characterized to investigate the effect of the ligand, cation and anion on the physiochemical properties of acetylacetonate-based MILs. It was found that thermal stabilities as high as 260 °C could be achieved by incorporating aromatic moieties in the anion structure. Additionally, the magnetic moment could be modulated by simply changing the transition metal in the anion. Magnetic moment values of 2.8 μB, 4.5 μBand 5.6 μB were obtained by using Ni(II), Co(II), and Mn(II) as the metal centers, respectively. Furthermore, the viscosity of the MILs could be tailored from a few hundred centipoise to several thousand centipoise, increasing their potential applications in numerous interdisciplinary fields. Moreover, the MILs synthesized in this study were found to be insoluble in water at a MIL-to-solvent ratio of 0.01% (w/v), making them potentially useful in targeted separations, where very hydrophobic solvents are highly desired