Rheological characterization of fibrillated cellulose suspensions via bucket vane viscometer

This paper discusses the practical application of a bucket vane viscometer in the characterization of novel nanofibrillated cellulose suspensions. Specifically, we use two different grades of nanocellulose, Masuko grinded and TEMPO oxidized ones. We work at the consistency range of 1–2.3 % w/w. We find, in agreement to more accurate rheometer based experiments, that both these materials behave in a highly non-linear manner. Thus, as we discuss in this paper, using a wide gap device necessitates the use of a correction algorithm in the conversion of the angular velocity to global shear rate to access the materials intrinsic, geometry independent, flow behavior. Furthermore, from the application viewpoint, we find that the classically measured low shear rate viscosity is not a good quantity to characterize these materials.     

Mass spectra of chlorinated aromatics formed in pulp bleaching: I—chlorinated catechols

A systematic study on the electron impact mass spectra of all nine chlorinated catechols in presented. Metastable ion analysis was used to elucidate the fragmentation pathways. The influence of the position of the chloro substituents can be used to distinguish the structural isomers. In this respect the most characteristic fragment ions are [M? CHl]⁺˙, [M? HCOOH]⁺˙, [M? COCl]⁺, [M? HCl? CO]⁺˙, [M? CHOCl]⁺˙ and [M? HCl? HCl]⁺˙.     

Some Theory and an Approach to Solving Sequential Multiple-Criteria Decision Problems

This paper examines a sequential multiple-criteria decision problem. The problem arises when a decision-maker is unable to consider all possible decision alternatives simultaneously. The decision-maker evaluates only a subset of all decision alternatives, from which he chooses the most preferred solution. Obviously, this solution is not necessarily ‘globally’ best. An interesting question is: how good is the most preferred solution and what are the chances of finding a better solution by considering additional alternatives? A unified approach to solving this problem based on probability theory is presented and illustrated with numerical examples.     

An extension of Picard's theorem for meromorphic functions of small hyper-order

A version of the second main theorem of Nevanlinna theory is proved, where the ramification term is replaced by a term depending on a certain composition operator of a meromorphic function of small hyper-order. As a corollary of this result it is shown that if n∈N and three distinct values of a meromorphic function f of hyper-order less than 1/n² have forward invariant pre-images with respect to a fixed branch of the algebraic function τ(z)=z+αn−1z1−1/n+?+α₁z1/n+α₀ with constant coefficients, then f○τ≡f. This is a generalization of Picard's theorem for meromorphic functions of small hyper-order, since the (empty) pre-images of the usual Picard exceptional values are special cases of forward invariant pre-images.     

Porous Biodegradable Scaffold: Predetermined Porosity by Dissolution of Poly(ester‐anhydride) Fibers from Polyester Matrix

A novel selective leaching method for the porogenization of the biodegradable scaffolds was developed. Continuous, predetermined pore structure was prepared by dissolving fast eroding poly(ε‐caprolactone)‐based poly(ester‐anhydride) fibers from the photo‐crosslinked poly(ε‐caprolactone) matrix. The porogen fibers dissolved in the phosphate buffer (pH 7.4, 37 °C) within a week, resulting in the porosity that replicated exactly the single fiber dimensions and the overall arrangement of the fibers. The amount of the porosity, estimated with micro‐CT, corresponded with the initial amount of the fibers. The potential to include bioactive agents in the porogen fibers was demonstrated with the bioactive glass.

     

Comparing the performance of FLUFF-BALL to SEAL-CoMFA with a large diverse estrogen data set: from relevant superpositions to solid predictions

In this work a template-based molecular mechanistic superposition algorithm FLUFF (Flexible Ligand Unified Force Field) and an accompanying local coordinate QSAR method BALL (Boundless Adaptive Localized Ligand) are validated against the benchmark techniques SEAL (Steric and Electrostatic Alignment) and CoMFA (Comparative Molecular Field Analysis) using a large diverse set of 245 xenoestrogens extracted from the EDKB (Endocrine Disruptor Knowledge Base) maintained by NCTR (National Centre for Toxicological Research). The results indicate that FLUFF is capable of generating relevant superpositions not only for BALL but also for CoMFA, as both techniques give predictive QSAR models. When the BALL and CoMFA methods are compared, it is clear that the BALL algorithm met or even exceeded the results of the standard 3D-QSAR method CoMFA using alignments either from the tailor-made superposition technique FLUFF or the reference method SEAL. The FLUFF-BALL method can be easily automated, and it is computationally light, providing thus a good computational "sieve" capable of fast screening of large molecule libraries.     

Gas-liquid chromatographic analyses : IV. Glass capillary gas chromatography of methyl and chloromethyl monochloro esters of aliphatic C5-carboxylic acids

The gas chromatography of methyl and chloromethyl esters of pivalic, 2-methylbutyric, isovaleric and valeric acid and certain of their monochloro derivatives was studied. Separation of the combined mixtures of methyl and chloromethyl esters was better on Carbowax 20M than on SE-30. The retention times of esters with subtituents adjacent (i.e. at C-2) to the carboxyl group appear to be sensitive to column polarity, particularly in the case of the chloromethyl esters. The retention order and relative retention times of compounds are discussed.     

Mass spectra of halogenated esters: 8. Methyl esters of 2,3-dichloro-, bromochloro- and dibromopropenoic acids

The mass spectral fragmentation of methyl esters of E and Z isomers of 2,3-dichloro-, 2-bromo-3-chloro-, 3-bromo-2-chIoro- and 2,3-dibromopropenoic acids have been investigated. The M^+˙ peak is shown with all isomers, the [M ? OCH₃]⁺, [M ? X]⁺, [M ? OCH₃ ? CO]⁺, [M ? OCH₃ ? CO ? X]^+˙ and [M ? OCH₃ ? CO ? X ? X]⁺ ions constituting abundant peaks in all spectra. The results, particularly from the bromochloro isomers, show that a halogen atom is eliminated from the 3- rather than the 2- position and from the Z rather than the E isomer. Bromine as a bulky atom is preferentially lost.     

Glass-capillary gas chromatography of chlorobenzenes on SE-30 and Carbowax 20M columns. Simultaneous determination of chlorobenzenes and chlorophenols

Summary Gas chromatography of benzene and all chlorobenzenes has been studied on SE-30 and Carbowax 20M glasscapillary columns under various operating conditions. The benzene isomers are eluted on both columns according to their boiling points. Separation of all components in a mixture is achieved on Carbowax 20M, whereas on SE-30 the peaks of closely related isomers overlapped. Also one partial overlapping is observed on a non-polar phase. The relative retention times for compounds are given and the retention order is discussed. The retention behaviour of chlorobenzenes and chlorophenols is compared. By using an SE-30 quartz-capillary column a mixture of 33 individual components gives 29 resolved peaks the analysis time being less than 26 minutes. A polar column proved to be unsuitable for the separation of polychlorophenols.