The heat capacity of the restricted primitive model electrolyte

The constant-volume heat capacity, C_V(T, rho), of the restricted primitive model (RPM) electrolyte is considered in the vicinity of its critical point. It is demonstrated that, despite claims, recent simulations for finite systems do not convincingly indicate the absence of a divergence in C_V(T, rho)--which would point to non-Ising-type criticality. The strong qualitative difference between C_V for the RPM and for a Lennard-Jones fluid is shown to result from the low critical density of the former. If one considers the theoretically preferable configurational heat-capacity density, C_V/V, the finite-size results for the two systems display qualitatively similar behavior on near-critical isotherms.Comment: 5 Pages, including 5 EPS figures. Also available as PDF file at http://pallas.umd.edu/~luijten/erikpubs.htm

Exploring the democratic potential of online social networking: The scope and limitations of e-participation

Copyright © 2012 by the Association for Information Systems.The availability and promise of social networking technologies with their perceived open philosophy has increasingly inspired citizens around the world to participate in political activity on the Web. Recent examples range from opposing public policies, such as government funding cuts, to organizing revolutionary social movements, such as those in the Middle East and North Africa. Although online spaces create remarkable opportunities for various forms of political action, there are concerns over the power of existing institutions to control and even censor such interaction spaces. The objective of this article is to draw together different insights on the online engagement phenomenon, highlighting both its potential and limitations as a mechanism for fostering democratic debate and influencing policy making. We examine recent examples from Europe, the Middle East and Latin America. Finally, we summarize the implications of our work and outline directions for further research

We have always been transreligious: An introduction to transreligiosity

The paper is a proposition and exploration of the term ‘transreligiosity’. We argue that transreligiosity is more apt to describe the transgressive character of religiosity, focusing more particularly on the transversality of spaces, symbolic or otherwise, which are created in religious phenomena. We examine the porosity of religious boundaries and, ultimately, propose the term transreligiosity to embrace them, placing emphasis on their transreligious character, while perceiving them as a pivotal fragment of transreligiosity. We take some of Latour’s key concepts on ‘purification’, to argue for the ultimate impossibility of it in the sphere of religiosity. While processes of purification have been powerful through efforts to institutionalize and centralize religiosity, on a vernacular level, this has had a contrary effect. Religious subjects have been distanced from a more direct participation (‘mediation’). Hence, they are constantly creating transreligious instances in order to abolish and transgress those rigid borders.info:eu-repo/semantics/acceptedVersio

Universality of Ionic Criticality: Size- and Charge-Asymmetric Electrolytes

Grand canonical simulations designed to resolve critical universality classes are reported for $z$:1 hard-core electrolyte models with diameter ratios $\lambda {=} a_+/a_- {\lesssim} 6$. For $z {=} 1$ Ising-type behavior prevails. Unbiased estimates of $T_c(\lambda)$ are within 1% of previous (biased) estimates but the critical densities are $\sim$5 % lower. Ising character is also established for the 2:1 and 3:1 equisized models, along with critical amplitudes and improved $T_c$ estimates. For $z {=} 3$, however, strong finite-size effects reduce the confidence level although classical and O$(n {\geq} 3)$ criticality are excluded.Comment: 4 pages, 3 figure

An innovative data mining procedure, using clean algorithm and factor analysis, for irregularly sampled temporal environmental data sets

Οι περιβαλλοντικές βάσεις δεδομένων συχνά αντιμετωπίζουν τα προβλήματα της άτακτης δειγματοληψίας στον χρόνο και της έλλειψης μετρήσεων για κάποιες περιόδους. Το γεγονός αυτό εμποδίζει τη χρήση των κλασικών μεθόδων ανάλυσης χρονοσειρών, οι οποίες απαιτούν σταθερό χρονικό βήμα ενώ ταυτόχρονα τα χρονικά κενά εισάγουν δυσκολίες στην χρήση των περισσοτέρων μεθόδων πολυδιάστατης σταπστικής ανάλυσης. Η παρούσα εργασία προτείνει ένα πλήρες μεθοδολογικό σχήμα ανάλυσης χρονικών περιβαλλονπκών δεδομένων με δειγματοληπτική ανομοιογένεια, στο οποίο γίνεται χρήση του αλγορίθμου CLEAN και της Παραγοντικής ανάλυσης (Factor Analysis). Ο αλγόριθμος CLEAN έχει την ικανότητα να αναπλάθει τις αρχικές χρονοσειρές της βάσης δεδομένων χρησιμοποιώντας φασματική ανάλυση και να δημιουργεί καινούργιες με σταθερό χρονικό βήμα και έλλειψη κενών. Λαμβάνει χώρα δηλαδή τόσο συμπλήρωση των κενών τ?/ς βάσης, όσο και «εξυγίανση» της δειγματοληψίας της. Η παραγοντική ανάλυση ομαδοποιεί τις μεταβλητές, ανάλογα με τον περιβαλλοντικό μηχανισμό από τον οποίο κάθε μια ελέγχεται και επιπλέον αποκαλύπτει τη χαρακτηριστική χρονική διακύμανση της κάθε ομάδας. Το συγκεκριμένο μεθοδολογικό σχήμα εφαρμόστηκε με πλήρη επιτυχία σε μια βάση υδροχημικών δεδομένων μεγάλης χρονικής περιόδου (1980-94) στον ποταμό ΣτρυμόναEnvironmental data are often irregularly collected in the time domain due to various reasons which affect the field sampling schedule. As a result, data sets with uneven time step and time periods with no measurements are frequently built. Many problems occur in such data sets when processed owing to that neither statistical nor spectral analysis methods can easily be applied to them without any specific pre-treatment. In our study it is demonstrated a unified methodological scheme especially designed to deal with incomplete and unevenly sampled temporal data sets. This method consists of the CLEAN algorithm and the Factor analysis. The proposed methodology is successfully applied to data sets that belong to two sampling sites of the Greek river Strimona

Universality class of criticality in the restricted primitive model electrolyte

The 1:1 equisized hard-sphere electrolyte or restricted primitive model has been simulated via grand-canonical fine-discretization Monte Carlo. Newly devised unbiased finite-size extrapolation methods using temperature-density, (T, rho), loci of inflections, Q = ^2/ maxima, canonical and C_V criticality, yield estimates of (T_c, rho_c) to +- (0.04, 3)%. Extrapolated exponents and Q-ratio are (gamma, nu, Q_c) = [1.24(3), 0.63(3); 0.624(2)] which support Ising (n = 1) behavior with (1.23_9, 0.630_3; 0.623_6), but exclude classical, XY (n = 2), SAW (n = 0), and n = 1 criticality with potentials phi(r)>Phi/r^{4.9} when r \to \infty

Phase diagrams in the lattice RPM model: from order-disorder to gas-liquid phase transition

The phase behavior of the lattice restricted primitive model (RPM) for ionic systems with additional short-range nearest neighbor (nn) repulsive interactions has been studied by grand canonical Monte Carlo simulations. We obtain a rich phase behavior as the nn strength is varied. In particular, the phase diagram is very similar to the continuum RPM model for high nn strength. Specifically, we have found both gas-liquid phase separation, with associated Ising critical point, and first-order liquid-solid transition. We discuss how the line of continuous order-disorder transitions present for the low nn strength changes into the continuum-space behavior as one increases the nn strength and compare our findings with recent theoretical results by Ciach and Stell [Phys. Rev. Lett. {\bf 91}, 060601 (2003)].Comment: 7 pages, 10 figure