Viable system theory

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Dynamic fragmentation simulations are essential for predicting material response at high strain rates, yet explicit dynamic simulations that combine an extrinsic cohesive-zone model (CZM) with penalty-based contact often exhibit severe instabilities. In a two-dimensional benchmark, we observe exponential energy growth and resulting artificial fragmentation under standard contact penalty settings and time step choices, which motivates a systematic analysis of instability sources. Three mechanisms are isolate

Traditional x-ray photoelectron spectroscopy (XPS) relies upon a direct mapping between the photoelectron binding energies and the local chemical environment, which is well characterized by an electrostatic partial charges (PC) model for systems in equilibrium. However, the extension of this technique to out-of-equilibrium systems has been hampered by the lack of x-ray sources capable of accessing multiple atomic sites with high spectral and temporal resolution, as well as the lack of simple theoretical pro

Airborne transmission of respiratory pathogens depends on their ability to remain viable in drying respiratory droplets, yet the physicochemical drivers of bacterial inactivation during droplet evaporation remain poorly quantified. This study combines controlled droplet experiments with physicochemical modeling to investigate how osmotic pressure dynamics influence bacterial survival. Using Escherichia coli and Staphylococcus epidermidis as Gram-negative and Gram-positive surrogates, respectively, we measur

This chapter extrapolates Jean Baudrillard's notion of the simulacrum to re-examine the shifting nature of simulation as a museological paradigm. Revisiting the concept of the simulacrum specifically enables the reconceptualization of two distinct lineages in visualization and worldmaking for digital cultural heritage and museums. The first is the virtual museum, which is critiqued and compared to the metaverse or mirrorworld, as it exists entirely online.. An alternative conception is offered in an archeao

Accurate real-time modeling of multi-body dynamical systems is essential for enabling digital twin applications across industries. While many data-driven approaches aim to learn system dynamics, jointly predicting internal loads and system trajectories remains a key challenge. This dual prediction is particularly important for fault detection and predictive maintenance in continuously operating systems. Internal loads – such as contact forces – serve as early indicators of faults, reflecting changes due to

Naturalistic sensory feedback is crucial for improving the functionality and acceptance of upper-limb prostheses. Electrical stimulation of peripheral nerves via implanted electrodes has shown a viable approach to providing real-time sensory information to hand prostheses. Although the loss of digits accounts for most upper-limb amputations, no existing digital prosthesis incorporates sensory feedback. This would be particularly important in the case of thumb amputation, as it leads to major functional impa

The Dark Matter Particle Explorer (DAMPE), a satellite-borne experiment capable of detecting gamma rays from few GeV to 10 TeV, studies the galactic and extragalactic gamma-ray sky and is at the forefront of the search for dark-matter spectral lines in the gamma-ray spectrum. This report details the development of a convolutional neural network (CNN) model for the trajectory reconstruction of gamma rays. Four distinct models were trained with Monte-Carlo gamma-ray events, each taking a different resolution

Buoyant hydraulic fractures (HF) are a viable approach to model propagating magmatic intrusions in the lithosphere. Solutions for fully planar three-dimensional (3D) HF suggest the existence of a family of solutions as a function of fluid and solid properties [1]. Theoretically, such buoyant fractures ascent in a self-sustained manner if no heterogeneities exist. We investigate the presence of a neutral buoyancy line (NBL) as a possible arrest mechanism of such buoyant self-sustained fractures. The NBL stem

The article links two seemingly different fundamental theoretical concepts of autopoiesis and homeostasis and tries to apply them to the realm of socio-technical systems with the use of the Fractal Enterprise Model (FEM). Autopoiesis is the property of a s ...

Point cloud is a 3D image representation that has recently emerged as a viable approach for advanced content modality in modern communication systems. In view of its wide adoption, quality evaluation metrics are essential. In this paper, we propose and ass ...

The isolation of single biological cells and their further cultivation in dedicated arrayed chambers are key to the collection of statistically reliable temporal data in cell-based biological experiments. In this work, we present a hydrodynamic single cell trapping and culturing platform that facilitates cell observation and experimentation using standard bio-lab equipment. The proposed design leverages the stochastic position of the cells as they flow into the structured microfluidic channels, where hundre

Free boundary magnetohydrodynamic equilibrium states with spontaneous three dimensional deformations of the plasma-vacuum interface are computed for the first time. The structures obtained have the appearance of saturated ideal external kink/peeling modes. ...

This paper aims at answering the questions when and how do cooperatives compete in the globalised world? With the goal to answer these questions, a qualitative study was conducted based on a sample of 9 consumer and producer farmer cooperatives operating in Sao Miguel. Sao Miguel is an Azorean island, which main economic activity relies on the agriculture market, where cooperatives compete in the national and international markets. The results point that Azores presents specific characteristics in terms of

For the past century, the urban underground has been developed piecemeal rather than as the object of a long-term planning effort. There is a growing awareness by urban planners and engineers that the underground contains not only potential usable space, but also raw materials, groundwater and geothermal energy sources with which urban areas interact. As a complex system, the city is not simply a projection off a two-dimensional plane, but a system of layers and interactions between urbanization and ecologi

The constraints imposed during modeling must satisfy biologically representative phenotypes of the studied organism. Simultaneously, identification and analysis of these constraints enhances our understanding of the evolution/operational paradigms of the organism. It was postulated by Varma and Palsson[1] that it is possible to define limits on metabolic behavior using flux balance analysis, but in order to accurately capture the metabolic responses, detailed information about enzyme kinetics and their regu

Tensegrity structures are spatial systems that are composed of tension and compression components in a self-equilibrated prestress stable state. Although tensegrity systems were first introduced in 1950s, few examples have been used for civil engineering purposes. In this paper, tensegrity-ring modules are used for a deployable pedestrian bridge. Ring modules belong to a special family of tensegrity systems composed of a single strut circuit. Assembled in a “hollow-rope” structure, ring modules were shown t

Ring modules are tensegrity systems that include a single strut circuit and recently, they have been shown to be viable systems for pedestrian bridges. Furthermore, their shape can be controlled using cable actuation. This paper focuses on the deployment of a pentagonal tensegrity-ring module. A geometric study is conducted to identify the deployment-solution space without strut contact. Deployment paths and actuation requirements are explored. The structural response of the module during deployment is anal

This paper describes the European Commission Framework 7 funded project myCopter (2011-2014). The project is still at an early stage so the paper starts with the current transportation issues faced by developed countries and describes a means to solve them through the use of personal aerial transportation. The concept of personal air vehicles (PAV) is briefly reviewed and how this project intends to tackle the problem from a different perspective described. It is argued that the key reason that many PAV con

Cell microencapsulation is an active interdisciplinary research field. It requires the input from materials sciences, organic and physical chemistry, biology and medicine. Hydrogels are particularly suitable materials to form microspheres for cell entrapme ...

This paper reports the new combination of cell sorting and counting capabilities on a single device. Most state-of-the-art devices combining these technologies use optical techniques requiring complicate experimental setups and labeled samples. The use of a label-free, electrical device significantly decreases the system complexity and makes it more appropriate for use in point-of-care diagnostics. Living and dead yeast cells are separated by dielectrophoretic forces and counted using coulter counters. The

Viable system theory

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Stability of Extrinsic Cohesive-zone Model with Penalty-based Contact in Explicit Dynamic Fragmentation Simulations☆

Unraveling Real-Time Chemical Shifts in the Ultrafast Regime

Rate of osmotic pressure change in drying saliva microdroplets drives inactivation of surrogate respiratory bacteria

Simulacrum

Equi-Euler GraphNet: An equivariant, temporal-dynamics informed graph neural network for dual force and trajectory prediction in multi-body systems

Model-based analysis of a distal sensory feedback implant for thumb prostheses

A deep learning method for the trajectory reconstruction of gamma rays with the DAMPE space mission

Transition from Vertical to Lateral Diking at the Neutral Buoyancy Line

Using Enterprise Models to Explain and Discuss Autopoiesis and Homeostasis in Socio-technical Systems

Towards a Point Cloud Structural Similarity Metric

Highly efficient and gentle trapping of single cells in large microfluidic arrays for time-lapse experiments

Saturated ideak kink/peeling formations described as three-dimensional magnetohydrodynamic tokamak equilibrium states

The Cooperative model in the globalized market: the case of Azorean Agriculture Cooperatives

Towards the Layered City: Redefining the Role of Underground Resources in Future Urbanization

Identification of Feasible Metabolic Fluxes and Metabolite Concentrations using Large-scale Kinetic Models

Deployment aspects of a tensegrity-ring pedestrian bridge

Deployment analysis of a pentagonal tensegrity-ring module

myCopter – Enabling Technologies for Personal Aerial Transportation Systems

Hybrid Microspheres For Cell Encapsulation

Label-free Sorting and Counting of Yeast Cells for Viability Studies