Papers by Keyword: Self-Organization

Abstract: In present work a new setup for in situ studies of molecular self-assembling process for fabrication of ion-conducting membranes for “green” fuel cells was developed. Due to compactness, this unique setup can be used on the synchrotron beamlines. The GISAXS and optical microscopy data have shown the effectiveness of the control of molecular architecture by impact of high temperature, UV-irradiation and solvent vapors.

Abstract: The modularity logistics system is a new concept produced in network era of globalization. The modularity logistics systems have self-organization characteristic. Combining modularity theory with synergetics theory, the association between modularity logistics systems and logistics standardization system was analyzed. And from the self-organization’s point of view, analyzing the internal and external factors of modularity logistics systems, it was identified that the standardization degree and the modularity value of logistics systems are the order parameters among the co-evolutionary of modularity logistics systems. Finally, introducing synergetics to management science, the collaborative management model of modularity logistics systems is put forward based on the public information supporting platform.

Abstract: Locomotion consists of cyclic events controlled by the neuronal activity of networks called central pattern generators. For a correct management of pedestrian flows, under regular or safety-critical situations, a deep understanding of individual and crowd dynamics is crucial. Here, we examine the emergence of walking and running forms of human gait. Individual locomotion and its interaction with other pedestrians is studied. Another key aspect examined is the self-organization experienced by a group of individuals which is a key concept to understand crowd dynamics. Self-organization leads to emergent properties, meaning that the whole system has characteristics that differ qualitatively from those of the component parts. The mechanisms behind the emergence of self-organized pattern of motion are also studied.

Abstract: Copper chalcogenide nanoparticles (NPs) represent a promising material for solar energy conversion and electrical charge storage. We showed that aqueous synthesis of high quality monodispersed high-chalcocite Cu₂S NPs is possible. Here, different thioglycolic acid (TGA) concentrations were employed in studies made to investigate the effects of stabilities ratio on particle morphology. It was found that the stabilizes concentration plays a key role in the synthesis of Cu2S NPs, the reaction rate is fast at low concentrations of TGA, and the size range is lager, while flower-like cluster with sizes of 30 nm were formed at high concentrations of TGA. Rapid availability of our results will provide valuable insight into the controlled growth of aqueous dispersions of ternary copper chalcogenide NPs, stimulating further studies of these materials in green energy conversion technologies and drug delivery applications.

Abstract: Recent studies of plastic deformation using high-resolution experimental techniques bear witness that deformation processes are often characterized by collective effects emerging on an intermediate scale between the scales describing the dynamics of individual crystal defects or the macroscopic plastic flow. In particular, the acoustic emission (AE) reveals intermittency of plastic deformation in various experimental conditions, which is manifested by the property of scale invariance, a characteristic feature of self-organized phenomena. Some materials, e.g., Al or Mg alloys, display a macroscopic discontinuity of plastic flow due to the Portevin-Le Chatelier effect or twinning. These materials are therefore of special interest for the study of collective effects in plasticity. The present work reviews the results of a multiscale investigation of AE accompanying plastic deformation of such model alloys. The AE is analyzed by methods borrowed from the theory of nonlinear dynamical systems, including statistical and multifractal analyses.

Abstract: The problem of the onset of the Portevin-Le Chatelier (PLC) effect is revised by combining a study of the kinetics of the flow stress evolution upon abrupt changes in the applied strain rate and acoustic emission (AE) accompanying plastic deformation of an AlMg alloy. The kinetic measurements allow evaluating the strain-rate sensitivity of the flow stress and the time characteristics of transient processes as functions of plastic strain. Using known criteria of plastic instability, domains of instability are constructed in the (strain, strain rate) plane. A particular accent is put on the strain-rate range corresponding to the so-called “inverse” behavior. The comparison of such maps with experimental data on the critical strain testifies to the insufficiency of these criteria for explaining the onset of the PLC effect. Moreover, the slow transient kinetics contradicts observations of the fast development of stress drops. The AE measurements bear witness that the stress serrations are associated with bursts in duration of acoustic events generated by the collective motion of dislocations. The possible role of synchronization of dislocation dynamics on the onset of plastic instability is discussed.

Abstract: Statistical and multifractal properties of Barkhausen jumps in exchange-coupled ferromagnet/antiferromagnet bilayers are studied on Co/IrMn and NiFe/NiO heterostructures using a magneto-optical indicator film technique. The statistical analysis proves a nonstochastic character of magnetization jumps. In particular, power-law behavior is observed for Co/IrMn samples. Furthermore, the statistics depends on the ferromagnet layer thickness and antiferromagnet layer material structure. The average jump size displays an asymmetry between the forward and backward branches of the hysteresis loop, particularly pronounced for the structure with a thin Co layer. In spite of the observation of such an asymmetry in the activity of the domain nucleation and pinning centers, the statistical distributions of jumps do not show any significant differences for two branches of the hysteresis loop. The conclusion on a nonrandom character of the magnetization process is supported by the multifractal analysis which reveals the presence of correlations in the time arrangement of the Barkhausen jumps.

Abstract: This paper proposes a novel System of Systems (SoSs) framework in order to design and optimise Supply Chains (SCs). In this paper the characteristics of System of Systems and Supply Chains have been discussed and a similarity match has been made between the two. It is interesting to note that although some of these SoSs characteristics are intrinsic in nature of the SCs others such as evolutionary behaviour and self-organization need to be modelled. In this paper, an adaptive supply chain multi-level multi-objective optimisation framework has been proposed in order to have both evolutionary and self-organized behaviour. This framework is capable of performing both local and global optimisation and adaptation to different scenarios.

Abstract: It is shown, that reaction between polyacrylic acid and polyvinyl caprolactam leads to formation of wide range of different products. Besides classic interpolymer complexes and physically cross-linked hydrogels, the intermediates are formed. Those intermediates, particularly, include hydrophilic interpolymer associates, i.e. semistable polymer networks existing in dynamical mode, which is characterized by continuous process of formation/destroying of hydrogen bonds. Other intermediate products are relatively stable fragments of the polymer networks or associates stabilized by hydrogen bonds.

Abstract: In this study, it is aimed to introduce such a one-dimensional traffic model to investigate two-dimensional crossing traffic flow at crossroad that without traffic light. The full velocity difference model is modified to adaptive stop by referring stopping sight distance and to solve conflict at crossroad by integrating self-organized rules. Simulation of crossing traffic flow is conducted and discussed. Results such as flow rate, individual velocity and traveling time show the crossroad without traffic light has significant impact on traffic flow. It is hoped this work may provide valuable evacuation references for the emergency department and individual evacuees.