1,721,047 research outputs found
A COMPUTER STUDY OF A SIMPLE STATISTICAL-MECHANICAL MODEL OF PHOSPHOLIPID MONOLAYERS AND BILAYERS
No full text
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Effects of a dc bias on electrical impedance spectroscopy in electrolytic cells
No full textCharacterization of electrolytic cells is often inferred from measurements of their electrical properties as a function of frequency by applying a sinusoidal voltage. In some cases, a dc bias is intrinsically present in addition to the ac stimulus and its effects are often neglected although they may become relevant in certain situations. As a consequence, the interpretation of the observed results might be misleading. Our aim is to estimate the influence of the bias solving numerically the Poisson-Nernst-Planck model for an electrolytic cell submitted to an ac external voltage superimposed to a bias. According to our analysis, even in the case of a small bias, the estimated Debye frequency and the low-frequency resistance of the cell are significantly influenced by it
Adhesion and plasticity in the dynamic response of rough surfaces in contact
No full textSeveral phenomenological models have been proposed in the last decades to understand and describe the phenomenology of elastic hysteresis observed in dynamic experiments, i.e. the combination of nonlinear phenomena, usually referred to as “fast” and “slow” dynamics, including harmonic generation, resonance frequency shift, time variation of elastic properties when large conditioning strain is applied. These models correctly reproduce various experimental observations for repeated loading–unloading cycles in quasi-static conditions, but they lack a convincing interpretation in terms of possible physical mechanisms. The aim of this work is to provide a model for the description of the dynamic behavior of a material with an internal microcrack, which attempts to link measurable macroscopic observables to physical crack features at the microscale (e.g. crack concentration, roughness, adhesion, elasticity and plasticity). The existence of adhesive/continuous phases, of crack activation thresholds, of harmonic generation and of the presence of metastable equilibrium states are emerging features of the model and are proposed herein as a possible source of slow dynamics effects. The proposed model can serve as a basis for the extension to a more macroscopic view, i.e. a material containing a network of microcracks
- …
