Tetraalkylphosphonium Polyoxometalates as Novel Ionic Liquids.

The pairing of a Lindqvist or Keggin polyoxometalate (POM) anion with an appropriate tetraalkylphosphonium cation, [R{sub 3}R{prime}P]{sup +}, has been shown to yield an original family of ionic liquids (POM-ILs), among them salts liquid at or near ambient temperature. The physicochemical properties of several such 'inorganic liquids', in particular their thermal properties, suggests the possible application of these compounds as robust, thermally-stable solvents for liquid-liquid extraction. A preliminary evaluation of the potential of POM-ILs in this application is presented

Fast radiation-induced reactions in organic phase of SANEX system containing CyMe4-BTPhen extracting agent

The mechanism of radiation-induced fast reactions occurring in the early stages in the 1-octanol system containing 2,9-Bis-(5,5,8,8-tetramethyl-5,6,7,8-tetrahydro-benzo (Herbst et al., 2011; Nash et al., 2015; Bourg et al., 2015)triazin-3-yl)- (Herbst et al., 2011; Panak and Geist, 2013)phenanthroline (CyMe4-BTPhen) extracting agent were studied. This is a simplified model of the r-SANEX organic phase for the selective actinide(III)/lanthanide(III) separation. Effects of various scavengers as well as water content were under consideration. Radiation chemical yield of e−s (G(e−s)) and their molar absorption coefficient (ε(e−s)) in 1-octanol were found to be 130(10) nmol J−1 and 18500(700) M−1 cm−1, respectively. Rate constants of e−s reactions with H+, O2, CyMe4-BTPhen and its protonated form were found to be 1.5(3) × 109, 1.0(1) × 1010, 1.85(9) × 109, 1.9(6) × 109 M−1 s−1, respectively. The C37 value for scavenging of dry electrons (e−dry) by CyMe4-BTPhen was equal to 30.4(8) mM. Rate constants of H• reactions with CyMe4-BTPhen and its protonated form were found to be < 7.2 × 109 and 4.3(9) × 109 M−1 s−1, respectively. A relatively good extraction performance of the system studied under exposition to high radiation doses was explained on the basis of hydroxyloctyl substitution in a phenanthroline aromatic ring

Efficient seed computation revisited

International audienceThe notion of the cover is a generalization of a period of a string, and there are linear time algorithms for finding the shortest cover. The seed is a more complicated generalization of periodicity, it is a cover of a superstring of a given string, and the shortest seed problem is of much higher algorithmic difficulty. The problem is not well understood, no linear time algorithm is known. In the paper we give linear time algorithms for some of its versions-- computing shortest left-seed array, longest left-seed array and checking for seeds of a given length. The algorithm for the last problem is used to compute the seed array of a string (i.e., the shortest seeds for all the prefixes of the string) in O(n2) time. We describe also a simpler alternative algorithm computing efficiently the shortest seeds. As a by-product we obtain an O(n log(n/m)) time algorithm checking if the shortest seed has length at least m and finding the corresponding seed. We also correct some important details missing in the previously known shortest-seed algorithm Iliopoulos et al. (1996)