Synthesis and properties of poly(oxyethylene)s containing thioether,sulfoxide, or sulfone groups

Poly[oxy(ethylthiomethyl)ethylene] (ETE) was prepared from poly[oxy (chloromethyl)ethylene] (CE) by reaction with sodium ethanethiolate. Sulfoxide and sulfone analogues were synthesized by oxidation of the poly[oxy(ethylthiomethyl)ethylene]. By changing the chloromethyl/sodium ethanethiolate ratio, poly[oxy (chloromethyl)ethylene-co-oxy(ethylthiomethyl)ethylene] (CE-ETEs) were easily made. Poly[oxy(ethylsulfinylmethyl)ethylene] (ESXE), poly[oxy(chloromethyl)ethylene-co-oxy(ethylsulfinylmethyl)ethylene] (CE-ESXEs), poly[oxy(ethylsulfonylmethyl)ethylene] (ESE), and poly[oxy(chloromethyl)ethylene-co-oxy(ethylsulfonylmethyl)ethylene] (CE-ESEs) were obtained by oxidation of ETE or CE-ETEs. There was little if any chain degradation. The (co)polymer structures were confirmed by FTIR and ¹H-NMR spectroscopic studies. Their thermal properties were studied by DSC and TGA. T_gs of ETE, ESXE, and ESE were -57, 36, and 57°C, respectively, and T_d,os (initial decomposition temperature, TGA) were 331, 198, and 308°C, respectively. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 793–801, 1998     

Oxyethylene copolymers with chloromethyl and (alkylthio)methyl or (alkylsulfonyl)methyl side groups: Syntheses and Tg/composition relationships

New classes of copolymers, poly[oxy(chloromethyl)ethylene]/poly[oxy-((alkylthio)methyl)ethylene] copolymers (CE-ATEs), poly[oxy((alkylthio)methyl)-ethylene]s (ATEs), poly[oxy(chloromethyl)ethylene]/poly[oxy((alkylsulfonyl)meth-yl)ethylene] copolymers (CE-ASEs), and poly[oxy((alkylsulfonyl)methyl)ethylene]s (ASEs) have been made for the first time. The thioether-containing polymers (CE-ATEs and ATEs) were synthesized by reacting poly[oxy(chloromethyl)ethylene] (CE, poly(epichlorohydrin)) with different amounts of sodium alkanethiolates. The sulfone-containing polymers (CE-ASEs and ASEs) were synthesized by oxidizing the CE-ATEs and ATEs using m-chloroperoxybenzoic acid. The Fox equation, a linear relationship, fit the T_g/composition data for most CE-ATEs. The T_g's of the CE-ASEs showed positive deviations from those calculated using the Fox equation. The Johnston equation, in which steric and/or polar interactions between dissimilar monomeric units are considered by using T_gAB (the T_g of the AB or BA dyad), fit the T_g/composition data for all copolymers in this study. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36 : 495–504, 1998     

Grammatical Gender Disambiguates Syntactically Similar Nouns

Recent research into grammatical gender from the perspective of information theory has shown how seemingly arbitrary gender systems can ease processing demands by guiding lexical prediction. When the gender of a noun is revealed in a preceding element, the list of possible candidates is reduced to the nouns assigned to that gender. This strategy can be particularly effective if it eliminates words that are likely to compete for activation against the intended word. We propose syntax as the crucial context within which words must be disambiguated, hypothesizing that syntactically similar words should be less likely to share a gender cross-linguistically. We draw on recent work on syntactic information in the lexicon to define the syntactic distribution of a word as a probability vector of its participation in various dependency relations, and we extract such relations for 32 languages from the Universal Dependencies Treebanks. Correlational and mixed-effects regression analyses reveal that syntactically similar nouns are less likely to share a gender, the opposite pattern that is found for semantically and orthographically similar words. We interpret this finding as a design feature of language, and this study adds to a growing body of research attesting to the ways in which functional pressures on learning, memory, production, and perception shape the lexicon in different ways.     

Disparities between experimental and environmental conditions: Research steps toward making electrochemical water treatment a reality

Electrochemical water treatment is one of the key topics of environmental electrochemistry. Identifying electrocatalytic materials capable of electrogenerating high oxidant species in situ seems to have catalyzed researchers’ interest in these processes. While most studies have focused on ideal lab-made solutions, translation to higher technology readiness levels and commercialization requires reframing research questions in context of real water matrices. In this current opinion, we discuss disconnects that may occur when focusing on synthetic solution treatment rather than on real waters. Future research can fill the gaps identified herein, thus facilitating application of electrochemical water treatment technologies.     

An incompressible smoothed particle hydrodynamics scheme for Newtonian/non-Newtonian multiphase flows including semi-analytical solutions for two-phase inelastic Poiseuille flows

An incompressible smoothed particle hydrodynamics (ISPH) method is developed for the modeling of multiphase Newtonian and inelastic non-Newtonian flows at low density ratios. This new method is the multiphase extension of Xenakis et al, J. Non-Newtonian Fluid Mech., 218, 1-15, which has been shown to be stable and accurate, with a virtually noise-free pressure field for single-phase non-Newtonian flows. For the validation of the method a semi-analytical solution of a two-phase Newtonian/non-Newtonian (inelastic) Poiseuille flow is derived. The developed method is also compared with the benchmark multiphase case of the Rayleigh Taylor instability and a submarine landslide, thereby demonstrating capability in both Newtonian/Newtonian and Newtonian/non-Newtonian two-phase applications. Comparisons with analytical solutions, experimental and previously published results are conducted and show that the proposed methodology can accurately predict the free-surface and interface profiles of complex incompressible multi-phase flows at low-density ratios relevant, for example, to geophysical environmental applications.     

Ready Access to Anhydrous Anionic Lanthanide Acetates by Using Imidazolium Acetate Ionic Liquids as the Reaction Medium

Access to lanthanide acetate coordination compounds is challenged by the tendency of lanthanides to coordinate water and the plethora of acetate coordination modes. A straightforward, reproducible synthetic procedure by treating lanthanide chloride hydrates with defined ratios of the ionic liquid (IL) 1-ethyl-3-methylimidazolium acetate ([C₂mim][OAc]) has been developed. This reaction pathway leads to two isostructural crystalline anhydrous coordination complexes, the polymeric [C₂mim]_n[{Ln₂(OAc)₇}_n] and the dimeric [C₂mim]₂[Ln₂(OAc)₈], based on the ion size and the ratio of IL used. A reaction with an IL : Ln-salt ratio of 5 : 1, where Ln=Nd, Sm, and Gd, led exclusively to the polymer, whilst for the heaviest lanthanides (Dy−Lu) the dimer was observed. Reaction with Eu and Tb resulted in a mixture of both polymeric and dimeric forms. When the amount of IL and/or the size of the cation was increased, the reaction led to only the dimeric compound for all the lanthanide series. Crystallographic analyses of the resulting salts revealed three different types of metal-acetate coordination modes where η²μκ² is the most represented in both structure types.     

The value of foresight

Suppose you have one unit of stock, currently worth 1, which you must sell before time $T$. The Optional Sampling Theorem tells us that whatever stopping time we choose to sell, the expected discounted value we get when we sell will be 1. Suppose however that we are able to see $a$ units of time into the future, and base our stopping rule on that; we should be able to do better than expected value 1. But how much better can we do? And how would we exploit the additional information? The optimal solution to this problem will never be found, but in this paper we establish remarkably close bounds on the value of the problem, and we derive a fairly simple exercise rule that manages to extract most of the value of foresight.     

The (3+1)-dimensional Monge-Ampère equation in discontinuity wave theory: Application of a reciprocal transformation

It is shown that the complete exceptionality condition for discontinuity waves associated with a second-order non-linear hyperbolic equation of the form

Dual emission laser induced fluorescence for direct planar scalar behavior measurements

 In this paper, a new method of measuring scalar behavior in bulk aqueous fluid flows is presented. Using a simple ratiometric scheme, laser induced fluorescence from organic dyes can be normalized so that direct measurements of a scalar in the flow are possible. The technique dual emission laser induced fluorescence (DELIF) relies on normalizing the fluorescence emission intensity of one dye with the fluorescence emission intensity of a second dye. Since each dye fluoresces at a different wavelength, one can optically separate the emission of each dye. This paper contains an overview of the basic ratiometric technique for pH and temperature measurements as well as the spectral properties of nine water soluble dyes. It also covers the three most significant sources of error in DELIF applications. To demonstrate the technique, steady state turbulent jet mixing and temperature fields in a thermal plume were quantified. The accuracy was camera limited at under 3% of the fluorescence ratio which corresponds to 0.1 pH units or 1.8 °C. Received 7 June 1996/Accepted 17 June 1997