Reliability analysis of complex water distribution systems: the role of the network connectivity and tanks

A reliable water distribution network (WDN) can provide an adequate supply service to customers under both normal and abnormal working conditions. The WDN reliability analysis, therefore, is a keystone to improve the supply service efficiency. Strategies for reliability analysis are usually proved on small WDNs, which do not compare with large real complex systems in terms of number of water tanks, pressure reduction valves, variable speed pumps, controlled devices and possible alternative water supply schemes. The topological changes due to pipeline interruptions impact on emptying–filling of water tanks and network pressure status. This work proposes a two-level procedure for mechanical reliability assessment, suited for large real WDNs. It leverages a path/connectivity-based approach to set up reliability indicators for global-level analysis and local screening of the most critical scenarios. The employed advanced hydraulic model includes the automatic detection of topological changes and the robust modelling of water level in tanks using the generalized global gradient algorithm. The extended period simulation enables the reliability assessment of alternative water supply schemes and the sensitivity of tanks and controlled devices to single failure events. The procedure is demonstrated on a real complex network, being consistent with the ongoing digital transition in the WDN management sector.

Topology and Phase Transitions: A First Analytical Step towards the Definition of Sufficient Conditions

Different arguments led to supposing that the deep origin of phase transitions has to be identified with suitable topological changes of potential related submanifolds of configuration space of a physical system. An important step forward for this approach was achieved with two theorems stating that, for a wide class of physical systems, phase transitions should necessarily stem from topological changes of energy level submanifolds of the phase space. However, the sufficiency conditions are still a wide open question. In this study, a first important step forward was performed in this direction; in fact, a differential equation was worked out which describes how entropy varies as a function of total energy, and this variation is driven by the total energy dependence of a topology-related quantity of the relevant submanifolds of the phase space. Hence, general conditions can be in principle defined for topology-driven loss of differentiability of the entropy.

Selective oxidative protection leads to tissue topological changes orchestrated by macrophage during ulcerative colitis

Background and Aims: Ulcerative colitis(UC) is a chronic inflammatory bowel disorder with highly cellular heterogeneity. Mass cytometry(Cy-TOF) and single-cell RNA sequencing (scRNA-seq) have revealed cellular heterogeneity of UC. However, comprehensive elucidation of tissue topological changes within the UC ecosystem is still missing. And we aimed to illustrate compositional and spatial changes of the UC ecosystem.Methods: Imaging mass cytometry (IMC) and scRNA-seq were applied to depict the single-cell landscape of colon ecosystem.Results: We noticed tissue topological changes featured with macrophage disappearance reaction (MDR) in UC region. MDR only occurred for CD163+ tissue-resident macrophages. We found reactive oxygen species (ROS) level were higher in UC region but ROS scavenging enzyme SOD1/2 were barely detected in resident macrophages, resulting selective oxidative protection for inflammatory macrophages and resident macrophage disappearance reaction. Furthermore, inflammatory macrophages replaced resident macrophages during UC, which played a key role in forming the inflammatory cellular network by producing TNF-α and IL-1β. Conclusions: Our study dissected the microenvironment of UC lesions at single-cell resolution while preserving its architecture, based on which, we discovered the mechanism of MDR in UC region and resident macrophage specific MDR resulted in infiltration of inflammatory macrophage, which formed the cytokine producing network within the local cellular neighborhood.

Controlling Bifurcation in Electronic Implementation of Dynamical Systems

In the theoretical and experimental studies of bifurcations in dynamical systems, the adjustments of the parameter values play a key role. The reason is because small variations in these values may result in topological changes in the behavior of the flow of the system. Taking this into account, in this paper, a new design for controlling bifurcation, suitable for electronic implementations of chaotic systems, is presented. The variation of the bifurcation parameter is performed by means of an Arduino UNO micro-controller and a digital controlled potentiometer. In this way, the variation of the electronic components is performed in an automated manner, avoiding the intrinsic problems of a manual variation of the circuit parameters. As a particular example, a scaled Rössler system is considered. One of the advantages of the controlled automated bifurcation is that it is useful for analyzing the robustness of the different limiting behaviors of the system against parameter mismatches.