Some recent developments regarding the application of analytical modelling of systems susceptible to interactive buckling are presented. The aim of the current work is to highlight some advantages of mathematical mode...
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ISBN:
(纸本)9781315641645;9781138029279
Some recent developments regarding the application of analytical modelling of systems susceptible to interactive buckling are presented. The aim of the current work is to highlight some advantages of mathematicalmodelling for interpreting the mechanical response of practical nonlinear problems in structural engineering and mechanics. Two applications where prestressing is combined with nonlinear instability are presented. The presented cases have been used to validate numerical simulations and allow insights into the fundamental parameters that control large deflection behaviour.
Assessing the condition of water pipes is a complex task, partly due to scarcity of complete maintenance records and field observations. This makes it harder to identify the factors determining pipe condition and thei...
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ISBN:
(纸本)9781509054442
Assessing the condition of water pipes is a complex task, partly due to scarcity of complete maintenance records and field observations. This makes it harder to identify the factors determining pipe condition and their probabilistic relationships with the deterioration process. A challenge facing water utilities is to find an effective and reliable tool for assessing their pipelines and taking prompt decisions regarding repair and maintenance to extend the service life and keep them safe from sudden failures. This paper presents research on a new fuzzy-based methodology for modelling water pipe condition prediction. It proposes a hierarchical fuzzy rule-based model that uses a simplified and effective method for supporting the elicitation of the fuzzy rules and adapting uncertainty propagation that can be intuitively understood by human experts. The results of applying the model to the water pipes domain shows the plausibility of extending the approach to other knowledge domains based on human expertise.
In this present paper a model with media coverage and vaccination is proposed on the spread of H7N9 influenza. We worked out the disease-free equilibrium and basic reproductive number by mathematical method and analyz...
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In this present paper a model with media coverage and vaccination is proposed on the spread of H7N9 influenza. We worked out the disease-free equilibrium and basic reproductive number by mathematical method and analyzed the sensitivity and uncertainty of the basic reproductive number by random sampling. At the same time, we also make some simulation on the stability of the disease-free equilibrium and the influence of the media coverage on the spread of the disease. These conditions can be used to gain important insights into the effect of media coverage and treatment on the prevention and control of influenza. The simulations are also conducted to confirm and extend the analytic results.
In this paper a model suitable for representing the electrical dynamic behaviour of Sodium Metal Halides Batteries (SMHBs) has been reported. In particular, the Thevenin circuit approach has been investigated consider...
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In this paper a model suitable for representing the electrical dynamic behaviour of Sodium Metal Halides Batteries (SMHBs) has been reported. In particular, the Thevenin circuit approach has been investigated considering the equivalent circuit parameters depending on the State Of Charge (SOC). The proposed SMHB model has been developed referring to the experimental tests conducted on a commercial module with a capacity of 23.5 kWh and a rated discharge power of 7.8 kW. In order to develop the identification of the Thevenin circuit parameters, a numerical processing of the specific measurements of a SMHB test-bench, considering the dynamic analytic solution of Thevenin circuit battery voltage, has been carried out and discussed in detail. The proposed approach allows a significant reduction of steady state errors respect to the numerical fitting procedure. Finally, the optimization of the first step identification process has been performed obtaining a very small variation in the values of the identified parameters by means of the proposed approach. The comparison between the experimental and simulation results has confirmed the good accuracy of the proposed model in a defined SOC range.
This paper is the outcome of a small scale fuel cell project. Fuel cell is an electrochemical device that converts energy from chemical reaction to electrical work. Proton Exchange Membrane Fuel Cell (PEMFC) is one of...
This paper is the outcome of a small scale fuel cell project. Fuel cell is an electrochemical device that converts energy from chemical reaction to electrical work. Proton Exchange Membrane Fuel Cell (PEMFC) is one of the different types of fuel cell, which is more efficient, having low operational temperature and fast start up capability results in high energy density. In this study, a mathematical model of 1.2 W PEMFC is developed and simulated using MATLAB software. This model describes the PEMFC behaviour under steady-state condition. This mathematical modeling of PEMFC determines the polarization curve, power generated, and the efficiency of the fuel cell. Simulation results were validated by comparing with experimental results obtained from the test of a single PEMFC with a 3 V motor. The performance of experimental PEMFC is little lower compared to simulated PEMFC, however both results were found in good agreement. Experiments on hydrogen flow rate also been conducted to obtain the amount of hydrogen consumed to produce electrical work on PEMFC.
System identification or modelling is the process of building mathematical models of dynamical systems based on the available input and output data from the systems. This paper introduces system identification by usin...
System identification or modelling is the process of building mathematical models of dynamical systems based on the available input and output data from the systems. This paper introduces system identification by using ARX (Auto Regressive with eXogeneous input) and ARMAX (Auto Regressive Moving Average with eXogeneous input) models. Through the identified system model, the predicted output could be compared with the measured one to help prevent the motor faults from developing into a catastrophic machine failure and avoid unnecessary costs and delays caused by the need to carry out unscheduled repairs. The induction motor system is illustrated as an example. Numerical and experimental results are shown for the identified induction motor system.
We report on the mathematical and numerical modelling of amplified rogue waves driving a wave-energy device in a contraction. This wave-energy device consists of a floating buoy attached to an AC-induction motor and c...
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ISBN:
(纸本)9780791849989
We report on the mathematical and numerical modelling of amplified rogue waves driving a wave-energy device in a contraction. This wave-energy device consists of a floating buoy attached to an AC-induction motor and constrained to move upward only in a contraction, for which we have realised a working scale-model. A coupled Hamiltonian system is derived for the dynamics of water waves and moving wave-energy buoys. This nonlinear model consists of the classical water wave equations for the free surface deviation and velocity potential, coupled to a set of equations describing the dynamics of a wave-energy buoy. As a stepping stone, the model is solved numerically for the case of linear shallow water waves causing the motion of a simple buoy structure with V-shaped cross-sections, using a variational (dis)continuous Galerkin finite element method.
The method used for purchasing the corrosion behaviour the WC coatings deposited by plasma spraying, on a martensitic stainless steel substrate consists in measuring the electrochemical potential of the coating, respe...
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The method used for purchasing the corrosion behaviour the WC coatings deposited by plasma spraying, on a martensitic stainless steel substrate consists in measuring the electrochemical potential of the coating, respectively that of the substrate, immersed in a NaCl solution as corrosive agent. The mathematical processing of the obtained experimental results in Matlab allowed us to make some correlations between the electrochemical potential of the coating and the solution temperature is very well described by some curves having equations obtained by interpolation order 4.
mathematical models of the interplay between disease dynamics and humanbehavioural dynamics can improve our understanding of how diseases spread when individuals adapt their behaviour in response to an epidemic. Acco...
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mathematical models of the interplay between disease dynamics and humanbehavioural dynamics can improve our understanding of how diseases spread when individuals adapt their behaviour in response to an epidemic. Accounting for behavioural mechanisms that determine uptake of infectious disease interventions such as vaccination and non-pharmaceutical interventions (NPIs) can significantly alter predicted health outcomes in a population. However, most previous approaches that model interactions between humanbehaviour and disease dynamics have modelled behaviour of these two interventions separately. Here, we develop and analyze an agent based network model to gain insights into how behaviour toward both interventions interact adaptively with disease dynamics (and therefore, indirectly, with one another) during the course of a single epidemic where an SIRV infection spreads through a contact network. In the model, individuals decide to become vaccinated and/or practice NPIs based on perceived infection prevalence (locally or globally) and on what other individuals in the network are doing. We find that introducing adaptive NPI behaviour lowers vaccine uptake on account of behavioural feedbacks, and also decreases epidemic final size. When transmission rates are low, NPIs alone are as effective in reducing epidemic final size as NPIs and vaccination combined. Also, NPIs can compensate for delays in vaccine availability by hindering early disease spread, decreasing epidemic size significantly compared to the case where NPI behaviour does not adapt to mitigate early surges in infection prevalence. We also find that including adaptive NPI behaviour strongly mitigates the vaccine behavioural feedbacks that would otherwise result in higher vaccine uptake at lower vaccine efficacy as predicted by most previous models, and the same feedbacks cause epidemic final size to remain approximately constant across a broad range of values for vaccine efficacy. Finally, when individual
In this paper, we propose a method to optimise a theoretical control on a mathematical model of interactions between cancer cells and the immune system. The model consists of five ordinary differential equations descr...
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In this paper, we propose a method to optimise a theoretical control on a mathematical model of interactions between cancer cells and the immune system. The model consists of five ordinary differential equations describing the behaviour of a tumour cell population interacting with populations of immune cells, all cells being submitted to the effects of chemotherapy. Two constraints were added to reflect the biological specificity of the problem. The first one asserts that the number of cytotoxic T lymphocytes must remain above a given threshold at the terminal point in time. The second one keeps the drug concentration in the bloodstream below a threshold to reduce toxic side effects resulting from the damages of chemotherapy to healthy cells. Using Pontryagin's Maximum Principle and approximation methods for optimal control, we obtain bang-bang solutions for different scenarios.
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