On the Dynamics of a Biomimetic Model of a Sympodial Tree: From Bifurcations Diagrams and 6D Basins of Attraction to Dynamical Integrity and Robustness

2021 ◽  
Author(s):  
Nemanja Andonovski ◽  
Ivana Kovacic ◽  
Stefano Lenci
Keyword(s):  
Excitation Frequency ◽  
Computational Procedure ◽  
Basins Of Attraction ◽  
Nonlinear Behaviour ◽  
Cell Mapping ◽  
Damping Parameter ◽  
Potential Benefits ◽  
Numerical Tools ◽  
Dynamical Integrity ◽  
First Time

Abstract This work is concerned with a mechanical model of a sympodial tree with first-level branches, which has been shown to exhibit certain properties potentially suitable for biomimetic applications. To investigate these potential benefits further from the viewpoint of the system nonlinear behaviour under external periodic excitation, modern numerical tools related to the concept of dynamical integrity are either adjusted or newly developed for this system for the first time. First, multistable regions of interest are isolated from bifurcation diagrams and the effect of damping is investigated. Then, in order to obtain the corresponding basins of attraction of this highly dimensional model, an original computational procedure is developed that includes cell mapping with 406 cells, where each cell represents an initial condition required to construct the map. Full 6D basins are computed, and they are reported for various values of the damping parameter and the excitation frequency. Those basins are then used to calculate the dynamic integrity factors so that the dominant steady state can be determined. Finally, the integrity profiles are reported to illustrate how the robustness varies by changing the system parameters.

scholarly journals Vibrations attenuation of a system excited by unbalance and the ground movement by an impact element

2016 ◽  
Vol 1 (2) ◽  
pp. 603-616 ◽  
Author(s):  
Marek Lampart ◽  
Jaroslav Zapoměl
Keyword(s):  
Differential Equations ◽  
Research Work ◽  
Computational Procedure ◽  
Ground Movement ◽  
Frequency Interval ◽  
Nonlinear Behaviour ◽  
Helical Springs ◽  
Impact Element ◽  
The Individual ◽  
The Impact

AbstractThis paper concentrates on the vibrations attenuation of a rotor driven by a DC motor and its frame flexibly coupled with a baseplate by linear cylindrical helical springs and damped by an element that can work either in inertia or impact regime. The system oscillation is governed by three mutually coupled second-order ordinary differential equations. The nonlinear behaviour occurs if the impact regime is adjusted. The damping element operating in inertia mode reduces efficiently the oscillations amplitude only in a narrow frequency interval. In contrast, the damping device working in impact regime attenuates vibrations of the rotor frame in a wider range of the excitation frequencies and it can be easily extended if the clearances between the rotor casing and the damping element are controlled. The development of a computational procedure for investigation of vibration of a flexibly supported rotor and for its attenuation by the inertia and impact dampers; learning more on efficiency of the individual damping regimes; finding possibilities of extension of the frequency intervals of applicability of the damping device; and obtaining more information on the character of the vibration induced by impacts are the main contributions of this research work.

Economic Analysis of Residents’ Health Potential Benefits from PM2.5 Reduction Caused by New Ambient Air Quality Standard in Beijing

2012 ◽  
Vol 524-527 ◽  
pp. 3371-3375
Author(s):  
Xiu Teng Wang ◽  
Ya Jing Zhang ◽  
Ling Xu ◽  
Ling Lin ◽  
Dong Feng Gao ◽  
...  
Keyword(s):  
Air Quality ◽  
Ambient Air ◽  
Economic Loss ◽  
Quality Standard ◽  
Point Of View ◽  
Ambient Air Quality ◽  
Potential Benefits ◽  
Ambient Air Quality Standard ◽  
First Time ◽  
Pm2.5 Concentration

PM2.5 pollution causes great health hazards, which will finally result in much economic loss. In China, it is first time to take PM2.5 as a general limitation factor in the revised version of "Ambient Air Quality Standard". In this work, we take Beijing as investigation objective, choose five kinds of typical health impacts, and make rough economic estimation of the potential benefits from the decrease of PM2.5 concentration through the epidemic-doses model in a quantitative point of view. Assuming the PM2.5 pollution is controlled well and satisfies the requirement of Grade 2 and 1 of new standard, 1681 and 2269 million Yuan will be saved in Beijing considering only health aspects. So it is necessary to take PM2.5 into the new ambient air quality standard as a general indicator, which is overall beneficial for environment and economy.

Phonons in deformable microporous crystalline solids

2019 ◽  
Vol 234 (7-8) ◽  
pp. 513-527 ◽  
Author(s):  
Bogdan Kuchta ◽  
Filip Formalik ◽  
Justyna Rogacka ◽  
Alexander V. Neimark ◽  
Lucyna Firlej
Keyword(s):  
Periodic Structures ◽  
Structural Transformations ◽  
Crystalline Solids ◽  
Predictive Tool ◽  
Crystalline Materials ◽  
Numerical Tools ◽  
Collective Vibrations ◽  
First Time

Abstract Phonons are quantum elastic excitations of crystalline solids. Classically, they correspond to the collective vibrations of atoms in ordered periodic structures. They determine the thermodynamic properties of solids and their stability in the case of structural transformations. Here we review for the first time the existing examples of the phonon analysis of adsorption-induced transformations occurring in microporous crystalline materials. We discuss the role of phonons in determining the mechanism of the deformations. We point out that phonon-based methodology may be used as a predictive tool in characterization of flexible microporous structures; therefore, relevant numerical tools must be developed.

Liquid Sloshing Dynamics in a Container Subjected to Coupled Mode Excitation

2008 ◽  
Author(s):  
T. Nasar ◽  
S. A. Sannasiraj ◽  
V. Sundar
Keyword(s):  
Excitation Frequency ◽  
Qualitative Assessment ◽  
Floating Body ◽  
Nonlinear Behaviour ◽  
Wave Excitation ◽  
Coupled Mode ◽  
Sloshing Dynamics ◽  
Time Histories ◽  
Fill Level ◽  
The Individual

An experimental work has been carried out to study the phenomena of sloshing of liquid in a partially filled tank mounted on a barge exposed to regular beam waves. Liquid fill level with aspect ratio (hs/l, where hs is the static liquid depth and l is the tank length) of 0.325 is studied. The time histories of sloshing oscillation are measured along the length of container at predefined locations. The nonlinear behaviour of sloshing oscillation is observed for the regular wave excitation. The spectra of the sloshing oscillation and their qualitative assessment are reported. The individual sway and heave analytical model have been studied in order to substantiate the importance of coupled mode of excitation. Attempts are made to evaluate the harmonics present in the sloshing oscillation and compare with the results of earlier studies. In the present interaction study, it was found that the nonlinear response of the floating body also plays a role to induce violent sloshing oscillation. The effects of wave excitation frequency on the sloshing oscillation are reported.

scholarly journals Dynamic Cell Mapping Algorithm for Computing Basins of Attraction in Planar Filippov Systems

2017 ◽  
Vol 27 (12) ◽  
pp. 1730041 ◽  
Author(s):  
Christian Erazo ◽  
Martin E. Homer ◽  
Petri T. Piiroinen ◽  
Mario Di Bernardo
Keyword(s):  
Numerical Integration ◽  
Regulatory Networks ◽  
Adaptive Strategy ◽  
Basins Of Attraction ◽  
Physical Models ◽  
Cell Mapping ◽  
Stick Slip ◽  
Mapping Algorithm ◽  
Filippov Systems ◽  
Nonsmooth Systems

Discontinuities are a common feature of physical models in engineering and biological systems, e.g. stick-slip due to friction, electrical relays or gene regulatory networks. The computation of basins of attraction of such nonsmooth systems is challenging and requires special treatments, especially regarding numerical integration. In this paper, we present a numerical routine for computing basins of attraction (BA) in nonsmooth systems with sliding, (so-called Filippov systems). In particular, we extend the Simple Cell Mapping (SCM) method to cope with the presence of sliding solutions by exploiting an event-driven numerical integration routine specifically written for Filippov systems. Our algorithm encompasses a method for dynamic construction of the cell state space so that a lower number of integration steps are required. Moreover, we incorporate an adaptive strategy of the simulation time to render more efficiently the computation of basins of attraction. We illustrate the effectiveness of our algorithm by computing basins of attraction of a sliding control problem and a dry-friction oscillator.

scholarly journals Epigallocatechin-3-Gallate Improves Facial Dysmorphology Associated with Down Syndrome

2018 ◽  
Author(s):  
John M. Starbuck ◽  
Sergi Llambrich ◽  
Ruben González ◽  
Julia Albaigès ◽  
Anna Sarlé ◽  
...  
Keyword(s):  
Down Syndrome ◽  
Chromosome 21 ◽  
Current Evidence ◽  
High Dose ◽  
Facial Morphology ◽  
Egcg Treatment ◽  
Health Promoting ◽  
Potential Benefits ◽  
Facial Development ◽  
First Time

AbstractIn Down syndrome (DS), the overall genetic imbalance caused by trisomy of chromosome 21 leads to a complex pleiotropic phenotype that involves a recognizable set of facial traits. Several studies have shown the potential of epigallocatechin-3-gallate (EGCG), a green tea flavanol, as a therapeutic tool for alleviating different developmental alterations associated with DS, such as cognitive impairment, skull dysmorphologies, and skeletal deficiencies. Here we provide for the first time experimental and clinical evidence of the potential benefits of EGCG treatment to facial morphology. Our results showed that mouse models treated with low dose of EGCG during pre- and postnatal development improved facial dysmorphology. However, the same treatment at high dose produced disparate facial morphology changes with an extremely wide and abnormal range of variation. Our observational study in humans revealed that EGCG treatment since early in development is associated with intermediate facial phenotypes and significant facial improvement scores. Overall, our findings suggest a potential beneficial effect of ECGC on facial development, which requires further research to pinpoint the optimal dosages of EGCG that reliably improve DS phenotypes. Current evidence warns against the non-prescribed intake of this supplement as a health-promoting measure.

scholarly journals A Review: Inductively Coupled Plasma Reactive Ion Etching of Silicon Carbide

Materials ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 123
Author(s):  
Katarzyna Racka-Szmidt ◽  
Bartłomiej Stonio ◽  
Jarosław Żelazko ◽  
Maciej Filipiak ◽  
Mariusz Sochacki
Keyword(s):  
Silicon Carbide ◽  
Inductively Coupled Plasma ◽  
Etching Rate ◽  
Reactive Ion Etching ◽  
Semiconductor Processing ◽  
Ion Etching ◽  
Inductively Coupled ◽  
Hard Materials ◽  
Potential Benefits ◽  
First Time

The inductively coupled plasma reactive ion etching (ICP-RIE) is a selective dry etching method used in fabrication technology of various semiconductor devices. The etching is used to form non-planar microstructures—trenches or mesa structures, and tilted sidewalls with a controlled angle. The ICP-RIE method combining a high finishing accuracy and reproducibility is excellent for etching hard materials, such as SiC, GaN or diamond. The paper presents a review of silicon carbide etching—principles of the ICP-RIE method, the results of SiC etching and undesired phenomena of the ICP-RIE process are presented. The article includes SEM photos and experimental results obtained from different ICP-RIE processes. The influence of O2 addition to the SF6 plasma as well as the change of both RIE and ICP power on the etching rate of the Cr mask used in processes and on the selectivity of SiC/Cr etching are reported for the first time. SiC is an attractive semiconductor with many excellent properties, that can bring huge potential benefits thorough advances in submicron semiconductor processing technology. Recently, there has been an interest in SiC due to its potential wide application in power electronics, in particular in automotive, renewable energy and rail transport.

scholarly journals Dwell Time Modelling and Optimized Simulations for Crowded Rail Transit Lines Based on Train Capacity

2015 ◽  
Vol 27 (2) ◽  
pp. 125-135 ◽  
Author(s):  
Zhibin Jiang ◽  
Chao Xie ◽  
Tingting Ji ◽  
Xiaolei Zou
Keyword(s):  
Dwell Time ◽  
Urban Rail Transit ◽  
Rail Transit ◽  
Transit Systems ◽  
Time Simulation ◽  
Urban Rail ◽  
Micro Simulation ◽  
Potential Benefits ◽  
Passenger Trains ◽  
First Time

Understanding the nature of rail transit dwell time has potential benefits for both the users and the operators. Crowded passenger trains cause longer dwell times and may prevent some passengers from boarding the first available train that arrives. Actual dwell time and the process of passenger alighting and boarding are interdependent through the sequence of train stops and propagated delays. A comprehensive and feasible dwell time simulation model was developed and optimized to address the problems associated with scheduled timetables. The paper introduces the factors that affect dwell time in urban rail transit systems, including train headway, the process and number of passengers alighting and boarding the train, and the inability of train doors to properly close the first time because of overcrowded vehicles. Finally, based on a time-driven micro-simulation system, Shanghai rail transit Line 8 is used as an example to quantify the feasibility of scheduled dwell times for different stations, directions of travel and time periods, and a proposed dwell time during peak hours in several crowded stations is presented according to the simulation results.

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