Dendrite P Systems Toolbox: Representation, Algorithms and Simulators

Dendrite P systems (DeP systems) are a recently introduced neural-like model of computation. They provide an alternative to the more classical spiking neural (SN) P systems. In this paper, we present the first software simulator for DeP systems, and we investigate the key features of the representation of the syntax and semantics of such systems. First, the conceptual design of a simulation algorithm is discussed. This is helpful in order to shade a light on the differences with simulators for SN P systems, and also to identify potential parallelizable parts. Second, a novel simulator implemented within the PLingua simulation framework is presented. Moreover, MeCoSim, a GUI tool for abstract representation of problems based on P system models has been extended to support this model. An experimental validation of this simulator is also covered.Ministerio de Economía, Industria y Competitividad TIN2017-89842-P (MABICAP

Cloud chambers and crystal growth: Effects of electrically enhanced diffusion on dendrite formation from neutral molecules

We present an extension of the solvability theory for free dendrite growth that includes the effects of electrically enhanced diffusion of neutral polar molecules. Our theory reveals a new instability mechanism in free dendrite growth, which arises when electrically enhanced diffusion near the dendrite tip overwhelms the stabilizing influence of surface tension. This phenomenon is closely related to the growth instability responsible for the visualization of charged particle tracks in cloud chambers, and is expected for enhanced diffusion of neutral molecules, but not for the case of ionic diffusion. Above a threshold applied potential, the crystal growth can no longer be described by the usual solvability theory, and requires a new physical mechanism to limit the growth velocity. We also describe experimental observations of the free dendrite growth of ice crystals from water vapor in supersaturated normal air. These observations demonstrate the calculated growth instability, which results in the rapid growth of branchless ice needles with a tip velocity 5–50 times the normal dendrite tip velocity. The production of clean ice needles is useful for the study of ice crystal growth from vapor, allowing the controlled growth of isolated single-crystal samples. This instability mechanism may find further application in crystal growth from a wide variety of polar molecules

Electrically Induced Morphological Instabilities in Free Dendrite Growth

We describe a new instability mechanism in free dendrite growth, which arises from electrically enhanced diffusion of polar molecules near the dendrite tip. For a small applied potential, the dendrite tip velocity increases slowly with potential, as is described by an extension of normal solvability theory. Above a threshold potential, however, capillarity is insufficient to stabilize growth. We present observations that confirm this instability, which brings about a transition from enhanced normal dendrite growth to a rapidly growing needle morphology with strongly suppressed sidebranching