Reactor Comparison for the Esterification of Fatty Acids from Waste Cooking Oil

Esterification of the fatty acids contained in waste cooking oil with glycerol, a reaction involving immiscible and viscous reactants, was achieved in two pilot‐scale continuous pulsed reactors: the oscillatory baffled reactor and the helix reactor. In both reactors, with or without baffles, the reaction reaches its thermodynamic equilibrium at lower temperatures, shorter residence times and with higher selectivities than those reported in the literature. This equilibrium is then shifted by an increase in the excess of glycerol, or by removing water from the reactive media by an intermediary decantation or by the use of dodecylbenzene sulfonic acid, a surfactant catalyst. Further investigations would be required to increase the conversions without decreasing the selectivities, by increasing the initial amount of free fatty acids.     

Peptides in rainbow trout (Oncorhynchus mykiss) muscle subjected to ice storage and cooking

Although proteolysis during post mortem storage is an important factor affecting fish texture, little is known about degradation end-products. This study was performed to investigate the occurrence of low molecular weight peptides (<5 kDa) in post mortem rainbow trout muscle, during ice storage, and to evaluate their stability during cooking. It combined quantitative (amino acid analysis) and qualitative approaches (mass spectrometry). The results showed that muscle of trout was poor in peptides. These were mainly anserine and glutathione. Their concentration was almost unaffected by the seven days of ice storage and vacuum cooking for 5 min at 70 °C. MS analysis revealed a limited but highly reproducible appearance of small peptides in trout muscle during the ice storage and after cooking. The compounds detected by MS analysis remain to be characterised.     

The fair use doctrine: History, application, and implications for (new media) writing teachers

Writing teachers have always had to contend with plagiarism. However, the technology of the Internet and the thorny issues of copyright law complicate how we teach legal and ethical use of others’ materials in the networked classroom. Our pedagogy and curriculum choices and our students’ writing practices are shaped by a legal infrastructure that includes the fair use doctrine. Our understanding and knowledge of the fair use doctrine should become second nature to us. Critical awareness of fair use, the four-factor test, and how to conduct appropriate analyses when using others’ materials must become part of the everyday digital writing/new media classroom curriculum. To this end, the author summarizes the salient points of law and practice of fair use and demonstrates, in small ways, how the fair use doctrine can inform the teaching of writing in digital contexts. As teachers, researchers, and experts of writing, the discourse of fair use must be considered in addition to the discourse of plagiarism.     

Surface Functionalization with Phosphazenes: Part 6. Modification of Polyethylene-Co-Polyvinylalcohol Copolymer Surface Plates with Fluorinated Alcohols and Azobenzene Derivatives Using Chlorinated Phosphazenes as Coupling Agents

In this paper we describe a two-step surface modification process of poly(ethylene-co-vinyl alcohol) by exploiting hexachlorocyclophosphazene and poly(dichlorophosphazene) as coupling agents. Part of the P–Cl groups of the chlorophosphazenes is first reacted with the surface hydroxylic groups of the substrate to form covalent P–O–C bonds, the remaining being utilized for successive substitution reactions with different nucleophiles (i.e. 2,2,2-trifluoroethanol, heptadecafluorononanol and 4-hydroxyazobenzene). Modified surface properties, such as hydrophobicity improvement with fluorinated alcohols and photochromic features with the azobenzene derivative, were verified by contact angle measurements and UV–Vis spectroscopy, respectively, while changes in surface composition were demonstrated through XPS spectroscopy.     

Fuzzy Rough Sets: The Forgotten Step

Traditional rough set theory uses equivalence relations to compute lower and upper approximations of sets. The corresponding equivalence classes either coincide or are disjoint. This behaviour is lost when moving on to a fuzzy T-equivalence relation. However, none of the existing studies on fuzzy rough set theory tries to exploit the fact that an element can belong to some degree to several "soft similarity classes" at the same time. In this paper we show that taking this truly fuzzy characteristic into account may lead to new and interesting definitions of lower and upper approximations. We explore two of them in detail and we investigate under which conditions they differ from the commonly used definitions. Finally we show the possible practical relevance of the newly introduced approximations for query refinement     

The pure parsimony haplotyping problem: overview and computational advances

Haplotyping estimation from aligned single-nucleotide polymorphism fragments has attracted more and more attention in recent years due to its importance in analysis of many fine-scale genetic data. Its application fields range from mapping of complex disease genes to inferring population histories, passing through designing drugs, functional genomics, and pharmacogenetics. The literature proposes a number of estimation criteria to select a set of haplotypes among possible alternatives. Usually, such criteria can be expressed under the form of objective functions, and the sets of haplotypes that optimize them are referred to as optimal. One of the most important estimation criteria is the pure parsimony, which states that the optimal set of haplotypes for a given set of genotypes is that having minimal cardinality. Finding the minimal number of haplotypes necessary to explain a given set of genotypes involves solving an optimization problem, called the pure parsimony haplotyping (PPH) estimation problem, which is notoriously     -hard. This article provides an overview of PPH, and discusses the different approaches to solution that occur in the literature.     

Computational comparisons of different formulations for the Stackelberg minimum spanning tree game

Let be a given graph whose edge set is partitioned into a set R of red edges and a set B of blue edges, and assume that red edges are weighted and contain a spanning tree of G. Then, the Stackelberg minimum spanning tree game (StackMST) is that of pricing (i.e., weighting) the blue edges in such a way that the total weight of the blue edges selected in a minimum spanning tree of the resulting graph is maximized. In this paper, we present different new mathematical programming formulations for the StackMST based on the properties of the minimum spanning tree problem and the bilevel optimization. We establish a theoretical and empirical comparison between these new formulations that are able to solve random instances of 20–70 nodes. We also test our models on instances in the literature, outperforming previous results.