Bar-Ilan University

About: Bar-Ilan University is a education organization based out in Ramat Gan, Israel. It is known for research contribution in the topics: Population & Poison control. The organization has 12835 authors who have published 34964 publications receiving 995648 citations. The organization is also known as: Bar Ilan University & BIU.

Carbon-based composite materials for supercapacitor electrodes: a review

Abstract: Electrochemical capacitors, so-called supercapacitors, play an important role in energy storage and conversion systems. In the last decade, with the increasing volume of scientific activity and publications in this field, researchers have developed better tools to improve electrode materials. Although carbonaceous materials seem the most suitable for supercapacitor applications, a large diversity of materials has been proposed and studied. Yet, in order to accomplish performance beyond the limitations of each material, mainly in terms of energy density and durability, composite materials have been implemented, most of them being the combinations of carbon-based materials and other components. In this review, we present the recent advances in the field of composite materials that include at least one carbon-based component for supercapacitor electrodes. We focus on cases in which a single material by itself suffers from a drawback that can be overcome by combining it with other components, enabling the fabrication of a composite material with enhanced performance. We present several important compositions as well as the major routes of synthesis, characterization and performance of composite materials in this field.

Politically contestable rents and transfers

Abstract: A rent or transfer is politically contestable when policy decisions are subject to influence by potential beneficiaries and losers. This paper studies contestablility of rents and transfers when contenders place different valuations on the politically allocated prize. Asymmetric valuation inhibits participation by low-valuation contenders. The model explains the phenomena of small numbers of active participants in contests to exercise political influence and low lobbying and other influence-seeking outlays relative to the value of politically allocated prizes.

Spin-glass models of neural networks.

Abstract: Two dynamical models, proposed by Hopfield and Little to account for the collective behavior of neural networks, are analyzed. The long-time behavior of these models is governed by the statistical mechanics of infinite-range Ising spin-glass Hamiltonians. Certain configurations of the spin system, chosen at random, which serve as memories, are stored in the quenched random couplings. The present analysis is restricted to the case of a finite number p of memorized spin configurations, in the thermodynamic limit. We show that the long-time behavior of the two models is identical, for all temperatures below a transition temperature ${T}_{c}$. The structure of the stable and metastable states is displayed. Below ${T}_{c}$, these systems have 2p ground states of the Mattis type: Each one of them is fully correlated with one of the stored patterns. Below T\ensuremath{\sim}0.46${T}_{c}$, additional dynamically stable states appear. These metastable states correspond to specific mixings of the embedded patterns. The thermodynamic and dynamic properties of the system in the cases of more general distributions of random memories are discussed.