122,162 research outputs found
Mark-Houwink-Sakurada constants for cellulose-paraformaldehyde/dimethyl sulphoxide system
No full text247-250<span style="font-size:11.0pt;line-height:115%;
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constants for cellulose paraformaldehyde/dimethyl sulphoxide system have been
determined for characterization and simplification of the process for
subsequent determination of molecular weight of any other cellulose sample.</span
Mark-Houwink-Sakurada coefficients for conventional poly(methyl methacrylate) in tetrahydrofuran
No full textIntrinsic viscosities [η] in tetrahydrofuran (THF) at 30°C are reported for ten narrow molecular weight distribution poly(methyl methacrylate) (PMMA) samples covering nearly two orders of magnitude in molecular weight. By combining the viscosity results with absolute weight-average molecular weights Mathematical expression determined via low-angle laser light scattering (LALLS) experiments, we have accurately determined the Mark-Houwink-Sakurada (MHS) parameters for this polymer-solvent pair (K=7.56x105 and a=0.731, when [η] is in dL g-1). © 1993 Springer-Verlag
A Multi-Language Comparison of Influences on Author Verification using Character N-Grams
No full textWe create a new multi-language corpus for author verification based on Wikipedia talkpages, and evaluate the influence that differences in topic and time have on character n-gram author profiles. Topic alignment between two texts is found to increase author verification precision, and an authors writing style is found to change over time, but not more significantly after 3 years than after 1 year.Information ArchitectureWISElectrical Engineering, Mathematics and Computer Scienc
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Depolymerization kinetics of di(4-tert-butyl cyclohexyl) itaconate and Mark-Houwink-Kuhn-Sakurada parameters of di(4-tert- butyl cyclohexyl) itaconate and di-n-butyl itaconate
No full textMultipulse pulsed laser polymerization coupled with size exclusion chromatography (MP-PLP-SEC) has been employed to study the depropagation kinetics of the sterically demanding 1,1-disubstituted monomer di(4-tert-butylcyclohexyl) itaconate (DBCHI). The effective rate coefficient of propagation, kp eff, was determined for a solution of monomer in anisole at concentrations, cM 0, 0.72 and 0.88 mol L-1 in the temperature range 0 ≤ T ≤ 70°C. The resulting Arrhenius plot (i.e., ln kp eff vs. 1/RT) displayed a subtle curvature in the higher temperature regime and was analyzed in the linear part to yield the activation parameters of the forward reaction. In the temperature region where no depropagation was observed (0 ≤ T ≤ 50°C), the following Arrhenius parameters for kp were obtained (DBCHI, Ep = 35.5 ± 1.2 kJ mol-1, ln Ap = 14.8 ± 0.5 L mol-1 s-1). In addition, the k p eff data was analyzed in the depropagatation regime for DBCHI, resulting in estimates for the associated entropy (-ΔS = 150 J mol-1 K-1) of polymerization. With decreasing monomer concentration and increasing temperature, it is increasingly more difficult to obtain well structured molecular weight distributions. The Mark-Houwink-Kuhn- Sakurada (MHKS) parameters for di-n-butyl itaconate (DBI) and DBCHI were determined using a triple detection GPC system incorporating online viscometry and multi-angle laser light scattering in THF at 40°C. The MHKS for poly-DBI and poly-DBCHI in the molecular weight range 35-256 kDa and 36.5-250 kDa, respectively, were determined to be KDBI = 24.9 (103 mL g-1), αDBI = 0.58, KDBCHI = 12.8 (10 3 mL g-1), and αDBCHI = 0.63. © 2006 Wiley Periodicals, Inc
The vanishing author in computer-generated works: a critical analysis of recent Australian case law
No full textAbstract
The use of software is ubiquitous in the creation of many copyright works, yet the requirement in copyright law that every work have a human author who engages in independent intellectual effort means that its use may prevent copyright subsistence. Several recent Australian cases have refocused attention on authorship as an essential criterion of copyright subsistence, and these cases suggest that much computer-produced output may be authorless and thus lack copyright protection. This article, the first in a two-part series, analyses how each case deals with the question of authorship of computer-produced works and why the use of software diminishes copyright protection for a significant number of computer-generated works. The article critiques the application of conventional notions of human authorship developed in the pre-computer age to modern productions and suggests alternative approaches to authorship that satisfy both the major objectives of copyright policy and the need to adapt to the computer age. The article argues that, without a broader judicial approach to authorship of computer-generated works, Parliament must remedy the lacuna in protection for these ‘authorless’ works. Possible solutions for reform are suggested. In a forthcoming article, the author comprehensively examines those reform proposals
Macromolecular conformation of chitosan in dilute solution: A new global hydrodynamic approach
No full textChitosans of different molar masses were prepared by storing freshly prepared samples for up to 6 months at either 4, 25 or 40 °C. The weight-average molar masses, Mw and intrinsic viscosities, [η] were then measured using size exclusion chromatography coupled to multi-angle laser light scattering (SEC-MALLS) and a "rolling ball" viscometer, respectively. The solution conformation of chitosan was then estimated from:(a)the Mark-Houwink-Kuhn-Sakurada (MHKS) power law relationship [η] = kMwa and(b)the persistence length, Lp calculated from a new approach based on equivalent radii [Ortega, A., & Garcia de la Torre, J. (2007). Equivalent radii and ratios of radii from solution properties as indicators of macromolecular conformation, shape, and flexibility. Biomacromolecules, 8, 2464-2475]. Both the MHKS power law exponent (a = 0.95 ± 0.01) and the persistence length (Lp = 16 ± 2 nm) are consistent with a semi-flexible rod type (or stiff coil) conformation for all 33 chitosans studied. A semi-flexible rod conformation was further supported by the Wales-van Holde ratio, the translational frictional ratio and sedimentation conformation zoning. © 2008 Elsevier Ltd. All rights reserved
Diffusive author(s), cohesive author: Analysis of S/N (1994)
No full textThis study indicates the ways in which various aspects of the author(s) are brought forth in Dumb type’s performance art, the S/N production. Previous research has suggested a non-hierarchical organization of Dumb type and the absence of a “privileged author” in Dumb type’s collaborative work, S/N. However, the results that I have investigated from member’s interviews on the creative process of S/N along with my analysis of the recorded images of S/N, indicate a different aspect of the author(s). First, S/N was created through, so to speak, the collective ideas of the members of Dumb type. Further, S/N has at least nine quotations from previous performances, installations, and printed writings, besides the work-in-progress technique. Explicating one of the “author functions” as given by Michel Foucault, each text has plural subjects of the author. However, it has been revealed from members’ interviews that Teiji Furuhashi had a decision-making role in selecting the members’ ideas within the performance. Since then, S/N has had plural subjects of creation; however, Furuhashi is one of the subjects of creation along with the “privileged author.” S/N has plural authors (diffusive authors) yet at the same time, it has a “privileged author,” Teiji Furuhashi (cohesive author)
Dissipative Range Scaling of Higher Order Structure Functions for Velocity and Passive Scalars
No full textDifferently to Kolmogorov's second similarity hypothesis, we find that the 2n-th order velocity and scalar structure functions scale with n-th order moment of the energy dissipation and the scalar dissipation, respectively. The origins of this scaling are analyzed by the transport equations of the fourth order velocity and scalar increment moments and by direct numerical simulations
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