Belousov-Zhabotinsky liquid marbles in robot control

© 2019 Elsevier B.V. We show how to control the movement of a wheeled robot using on-board liquid marbles made of Belousov-Zhabotinsky solution droplets coated with polyethylene powder. Two stainless steel, iridium coated electrodes were inserted in a marble and the electrical potential recorded was used to control the robot's motor. We stimulated the marble with a laser beam. It responded to the stimulation by pronounced changes in the electrical potential output. The electrical output was detected by the robot. The robot changed its trajectory in response to the stimulation. The results open new horizons for applications using oscillatory chemical reactions in robotics

Thermal switch of oscillation frequency in belousov- zhabotinsky liquid marbles

© 2019 The Authors. External control of oscillation dynamics in the Belousov- Zhabotinsky (BZ) reaction is important for many applications including encoding computing schemes. When considering the BZ reaction, there are limited studies dealing with thermal cycling, particularly cooling, for external control. Recently, liquid marbles (LMs) have been demonstrated as a means of confining the BZ reaction in a system containing a solid-liquid interface. BZ LMs were prepared by rolling 50 ml droplets in polyethylene (PE) powder. Oscillations of electrical potential differences within the marble were recorded by inserting a pair of electrodes through the LM powder coating into the BZ solution core. Electrical potential differences of up to 100mV were observed with an average period of oscillation ca 44 s. BZ LMs were subsequently frozen to 218C to observe changes in the frequency of electrical potential oscillations. The frequency of oscillations reduced upon freezing to 11mHz cf. 23 mHz at ambient temperature. The oscillation frequency of the frozen BZ LM returned to 23 mHz upon warming to ambient temperature. Several cycles of frequency fluctuations were able to be achieved

Belousov-Zhabotinsky reaction in liquid marbles

In Belousov–Zhabotinsky (BZ) type reactions, chemical oxidation waves can be exploited to produce reaction-diffusion processors. This paper reports on a new method of encapsulating BZ solution in a powder coating of either polyethylene (PE) or polytetrafluoroethylene (PTFE), to produce BZ liquid marbles (LMs). BZ LMs have solid-liquid interfaces compared to previously reported encapsulation systems, BZ emulsions and BZ vesicles. Oscillation studies on individual LMs established PE-coated LMs were easier to prepare and more robust than PTFE-coated LMs. Therefore, this coating was used to study BZ LMs positioned in ordered and disordered arrays. Sporadic transfer of excitation waves was observed between LMs in close proximity to each other. These results lay the foundations for future studies on information transmission and processing arrays of BZ LMs. Future work aims to elucidate the effect of other physical stimuli on the dynamics of chemical excitation waves withinthese systems

Chemical Wave Computing from Labware to Electrical Systems

Unconventional and, specifically, wave computing has been repeatedly studied in laboratory based experiments by utilizing chemical systems like a thin film of Belousov–Zhabotinsky (BZ) reactions. Nonetheless, the principles demonstrated by this chemical computer were mimicked by mathematical models to enhance the understanding of these systems and enable a more detailedinvestigation of their capacity. As expected, the computerized counterparts of the laboratory based experiments are faster and less expensive. A further step of acceleration in wave-based computingis the development of electrical circuits that imitate the dynamics of chemical computers. A key component of the electrical circuits is the memristor which facilitates the non-linear behavior of the chemical systems. As part of this concept, the road-map of the inspiration from wave-based computing on chemical media towards the implementation of equivalent systems on oscillating memristive circuits was studied here. For illustration reasons, the most straightforward example was demonstrated, namely the approximation of Boolean gates

A programmable hybrid digital chemical information processor based on the Belousov-Zhabotinsky reaction

The exponential growth of the power of modern digital computers is based upon the miniaturization of vast nanoscale arrays of electronic switches, but this will be eventually constrained by fabrication limits and power dissipation. Chemical processes have the potential to scale beyond these limits by performing computations through chemical reactions, yet the lack of well-defined programmability limits their scalability and performance. Here, we present a hybrid digitally programmable chemical array as a probabilistic computational machine that uses chemical oscillators using Belousov-Zhabotinsky reaction partitioned in interconnected cells as a computational substrate. This hybrid architecture performs efficient computation by distributing information between chemical and digital domains together with inbuilt error correction logic. The efficiency is gained by combining digital logic with probabilistic chemical logic based on nearest neighbour interactions and hysteresis effects. We demonstrated the computational capabilities of our hybrid processor by implementing one- and two-dimensional Chemical Cellular Automata demonstrating emergent dynamics of life-like entities called Chemits. Additionally, we demonstrate hybrid probabilistic logic as a viable logic for solving combinatorial optimization problems

Bio-mimicry and self-organisation of the Belousov Zhabotinsky reaction

Introduction: The Belousov Zhabotinsky (BZ) reaction is commonly used as a proxy for biological systems in physical-chemistry experiments. The BZ reaction is well known to be influenced by environmental perturbations, very much like biological systems. The mechanisms of which have been studied to understand how this relates back to biology. Aim: There is a lack of knowledge regarding the effect external electric fields (EF) and surfactant concentration have on the BZ reaction, and how this relates to biological function in cells. We aim to use the BZ reaction as a model of how biological systems interact with one another, along with the interaction with their environment. Methods: Ferroin catalysed BZ solutions were prepared and pipetted in droplet form into an oil phase. The droplets were subjected to various external perturbations and recorded using a DSLR camera recording at 60 frames per second. The environmental stimulation involves varied power AC and DC fields, along with a range of concentrations of surfactant dissolved in the oil phase. Results: Firstly, the discovery of BZ droplet electrotaxis was reported and quantified, where the static EF was found to create an inhomogeneous distribution of ions within the droplet, which leads to a bias in the formation of leading centres (LC) across the droplet. The phenomena was then deployed as a form of push-pull mechanism on oscillating BZ droplets to cause their division. Finally, continuing from the division experiments, we study the synchronisation between the periodicity in a pair of droplets. We found that the oscillating droplets had an influence on one another, and would synchronise their beating behaviour according to one another. Conclusion: We have found that the ferroin-catalysed BZ droplets can be used to simulate biological redox signalling, and as a proxy for understanding processes from environmental signal detection to cell division, where our experiments have shown that an external EF can induce the electrostatic behaviour, and contribute to the droplet division event

RDF query and protocols language using for description and representation of web ontologies

The purpose of this article is to expose the metadata structure based on RDF (Resource Description Framework) and the way in which queries can be made using SPARQL (Protocol and RDF Query Language), as a principle for searching the Semantic Web. It also describes what must be considered to build a Web Ontology and the tools that can help the Software developer to make querys using SPARQL

Liquid Cybernetic Systems: The Fourth‐Order Cybernetics

Technological development in robotics, computing architectures and devices, and information storage systems, in one single word: cybernetic systems, has progressed according to a jeopardized connection scheme, difficult if not impossible to track and picture in all its streams. Aim of this progress report is to critically introduce the most relevant limits and present a promising paradigm that might bring new momentum, offering features that naturally and elegantly overcome current challenges and introduce several other advantages: liquid cybernetic systems. The topic describing the four orders of cybernetic systems identified so far is introduced, evidencing the features of the fourth order that includes liquid systems. Then, current limitations to the development of conventional, von Neumann‐based cybernetic systems are briefly discussed: device integration, thermal design, data throughput, and energy consumption. In the following sections, liquid‐state machines are introduced, providing a computational paradigm (free from in materio considerations) that goes into the direction of solving such issues. Two original in materio implementation schemes are proposed: the COlloIdal demonsTratOR (COgITOR) autonomous robot, and a soft holonomic processor that is also proposed to realize an autolographic system

A probabilistic chemical programmable computer

The exponential growth of the power of modern digital computers is based upon the miniaturisation of vast nanoscale arrays of electronic switches, but this will be eventually constrained by fabrication limits and power dissipation. Chemical processes have the potential to scale beyond these limits performing computations through chemical reactions, yet the lack of well-defined programmability limits their scalability and performance. We present a hybrid digitally programmable chemical array as a probabilistic computational machine that uses chemical oscillators partitioned in interconnected cells as a computational substrate. This hybrid architecture performs efficient computation by distributing between chemical and digital domains together with error correction. The efficiency is gained by combining digital with probabilistic chemical logic based on nearest neighbour interactions and hysteresis effects. We demonstrated the implementation of one- and two- dimensional Chemical Cellular Automata and solutions to combinatorial optimization problems.Comment: 20 page manuscript, 6 figures, 112 page supplementary volum