7,982 research outputs found
Velcrand Functionalized Polyethylene
No full textVelcrands are a specific class of cavitands whose complementary surfaces induce self-dimerization. The insertion of a velcrand as physical cross-linking unit into a polymer is reported. To this purpose, the velcrand was functionalized at the lower rim with an isocyanate group. The functional velcrand was reacted with poly (ethylene-co-(2-hydroxethylmethacrylate)) (PE-HEMA), a polymer equipped with free hydroxyl groups suitable for reaction with the isocyanate group. The obtained functionalized polymer was characterized by nuclear magnetic resonance (NMR), differential scanning calorimetry (DSC), and Fourier transform infrared spectroscopy (FTIR), proving the introduction of velcraplexes in the polymer. Films with varying amounts of velcrands were obtained by solution casting and slow evaporation, testifying the processability of the functionalized polymers. The obtained films were used to measure the oxygen barrier properties of the functionalized material
Reprocessable vinylogous urethane cross-linked polyethylene via reactive extrusion
No full textVitrimers are an emerging class of permanently cross-linked materials, where exchange reactions of
cross-links provide malleability. The most promising application of these materials is to impart reprocessability
to thermoset polymers, such as cross-linked polyethylene (PE). Here, a facile and easy to scale-up
method for the preparation of cross-linked PE vitrimers is presented by combining reactive extrusion and
injection molding using exchange reactions of vinylogous urethanes. Very low retention times (<15 min)
inside the extruder were required and the obtained elastomeric vitrimers have increased melt strength
and a cross-link density dependent plateau modulus. Control over the amount of cross-links per chain in
the final polymer was possible by varying the co-monomer feed in the preparation of the precursor polymers,
which allowed the tuning of the final material properties such as melt viscosity and rubber plateau
modulus. For polymers with an amount of >1.9 cross-links per chain, stress-relaxation is largely controlled
by the exchange reactions of vinylogous urethanes. It was found that the activation energy depended on
the cross-link density. Reprocessability of the vitrimers is demonstrated by four cycles of molding and
tensile strength testing revealing minor degradation of the material
Jonathan Ned Katz Author Event: The Daring Life and Dangerous Times of Eve Adam
No full text“The Daring Life and Dangerous Times of Eve Adams,” interview with author, Jonathan Ned Katz, moderated by Emily Weiner (WWU) and organized by Congregation Beth Israel
Contemporary Literature. Analysis of Jonathan Bazzi's novels
No full textopenDopo una breve panoramica della letteratura italiana degli ultimi vent’anni si analizzano i due romanzi di Jonathan Bazzi "Febbre" e "Corpi minori" dai punti di vista formale, stilistico e tematico. Si discute inoltre il rapporto tra social media, autofiction e autore; nel capitolo 4 si riporta l'intervista che Bazzi ci ha gentilmente concesso, in cui questi argomenti vengono ripresi.
Si individuano alcune differenze che i testi mostrano rispetto alla letteratura moderna, e gli aspetti che hanno in comune con quella contemporanea; nel fare questo si accennano quindi alcune caratteristiche della società che li ha prodotti.The paper starts off with a brief overview of the contemporary Italian literature; then the reader is guided through an analysis of Jonathan Bazzi's novels, "Febbre" ("Fever") and "Corpi minori" ("Minor bodies"), both translated in English and published by Scribe. The relationship between author, autofiction and social media will also be discussed; in chapter four the reader will find the interview Bazzi kindly granted us
Gas barrier film
No full textThe invention relates to a process for the prepn. of a gas barrier film, comprising 1) providing an olefin copolymer comprising: (i) recurring units A derived from an olefin and (ii) recurring units B derived from a compd. according to formula (I), (II) or (III): (I) wherein R1 is selected from -H or -CH3; R2 is selected from -0-, -(CO)-(NH)- or -(CO)-O-; R3 is a moiety comprising 1 -30 carbon atoms; and n is an integer between 1 and 10, (II) wherein R1 is selected from -H or -CH3 and p is an integer between 1 and 10, (III) wherein R1 is selected from -H or -CH3 and q is an integer between 1 and 10, 2) grafting a graft compd. represented by the formula (IV) or (V) to the olefin copolymer (IV) wherein R4 is independently -H, C1 -C10 linear, branched or cyclic alkyl; X is -NH- or -O- and R5 is represented by the formula: (A) where r is an integer between 1 and 20; Y is -NCO, halogen (I, Br, CI, F), -Si(OMe)3, -N=C=S, -N3, -COOH, an amino acid or an amino ester, (V) wherein each of R6, R7, R8 and R9 is independently -H, C1 -C10 linear, branched or cyclic alkyl; X is -NH- or -O- and R5 is represented by the formula: (A) where r is an integer between 1 and 20; Y is -NCO, halogen (I, Br, CI, F), -Si(OMe)3, -N=C=S, -N3, -COOH, an amino acid or an amino ester and 3) shaping the grafted polymer obtained by step 2) into a film
Administration and Curricula of the Introductory Graduate Music Research Course
No full textThe introductory research course is an integral part of many graduate music programs, yet there have been few studies that discuss its curricula across institutions. A questionnaire was sent to instructors of the course to identify shared pedagogical approaches among North American schools of music. The survey was divided into sections that prompted respondents to identify issues discussed in the course, including the types and titles of resources, research methodologies, and library use topics. With a response rate of over 40 percent, the survey also contains valuable data concerning the professional identifications of instructors, assignments used for grading, common textbooks, perception of the course’s efficacy, and more. Shared features of the course included the importance of electronic resources; the minimal use of Internet-mediated instruction formats; a strong preference for English-language materials; and a focus on resources such as databases, style guides, collected works, monuments of music, and thematic catalogs over and above others such as repertoire guides, discographies, directories, and iconographies.Peer reviewedThis publication first appeared in Notes Volume 71, Number 3, March 2015, pp. 448-478. This material may not be copied or reposted without explicit permission. Copyright 2015, Jonathan Sauceda
Polyolefin terpolymers, vitrimers made therefrom, and method of making the polyolefin terpolymers and vitrimers
No full textTerpolymers that include a hydrocarbon unit, an acetoacetate terminated unit and a hydroxy -terminated unit are described. Vitrimers made from these terpolymers are also described
Citizen participation in news
No full textThe process of producing news has changed significantly due to the advent of the Web, which has enabled the increasing involvement of citizens in news production. This trend has been given many names, including participatory journalism, produsage, and crowd-sourced journalism, but these terms are ambiguous and have been applied inconsistently, making comparison of news systems difficult. In particular, it is problematic to distinguish the levels of citizen involvement, and therefore the extent to which news production has genuinely been opened up. In this paper we perform an analysis of 32 online news systems, comparing them in terms of how much power they give to citizens at each stage of the news production process. Our analysis reveals a diverse landscape of news systems and shows that they defy simplistic categorisation, but it also provides the means to compare different approaches in a systematic and meaningful way. We combine this with four case studies of individual stories to explore the ways that news stories can move and evolve across this landscape. Our conclusions are that online news systems are complex and interdependent, and that most do not involve citizens to the extent that the terms used to describe them imply
To what extent is Lemuel Gulliver in Gulliver’s Travels by Jonathan Swift a reflection of the writer with regard to political and religious views, and attitudes toward women and the concept of family?
No full textThis extended essay is an examination of the extent to which the protagonist Lemuel Gulliver in Gulliver’s Travels is a reflection of Jonathan Swift. It involves the exploration of this research question in terms of politics, religion, attitude to women and family; with references to this piece of literature and some secondary resources when necessary. The quotations from published literary criticism are either refuted by examples from the novel or supported in the light of evidence from the novel. Other secondary resources include Swift’s two other prose works, The Modest Proposal and A Letter to a Very Young Lady on Her Marriage, which are referred to briefly for clarification of the evidence. The purpose of this study is to analyse in what ways and to what extent the protagonist is an author-surrogate in the abovementioned ways.
This essay is comprised of two sections, namely “politics and religion” and “women and family”, each focusing on a particular aspect of the investigation. In the first section, Swift’s political and religious standpoint is discussed extensively in order to correctly evaluate Gulliver’s paradigm. By making connections between the beliefs of the author and those of Gulliver, the relation between the two is established to support the claim of this essay. In the second section, the female figures in the novel and Gulliver’s perception of them are inspected. The plot is also taken into consideration in this part of the inquiry although the central focus is on the persona.
In the conclusion, it is validated that Gulliver is a reflection of Jonathan Swift with regard to political and religious vision, and attitude towards women and family, by juxtaposing and assembling the main elements of personification of Gulliver and Jonathan Swift’s personal ideas and experiences
Dynamic Cross-Linking of Polyethylene via Sextuple Hydrogen Bonding Array
No full textMultiple hydrogen bonding motifs
are promising tools for polymer
functionalization to obtain adaptable networks combining advantages
of permanently cross-linked systems with processability of thermoplastics.
Here we describe the use of a new multiple hydrogen bonding motif
to impart increased tensile strength, stiffness, barrier properties,
and a plateau modulus after melting to functional polyolefins, while
retaining adaptability of the polymer network. The cross-linked nature
of these polymers was elucidated by thermal and mechanical analysis,
revealing a raised glass transition and rheology similar to permanently
cross-linked polymer matrices. The apolar polymer matrix was found
to stabilize the new hydrogen bonding motif at elevated temperatures.
The resulting polymer showed thermal resistance superior to ureidopyrimidone
(UPy) motif functionalized materials, the most commonly employed synthetic
multiple hydrogen bonding motif to date
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