The paper reports findings on mathematicalmodelling of ingots of different geometry. It is established that V-shaped cracks concentrated in the ingot bottom are gradually removed through upset, while arch-shaped crac...
The paper reports findings on mathematicalmodelling of ingots of different geometry. It is established that V-shaped cracks concentrated in the ingot bottom are gradually removed through upset, while arch-shaped cracks located around the sedimentation cone top open up. A computer simulation made it possible to calculate efficient deformations in the workpiece axial zone. An alteration of the ingot geometry leads to an increase in efficient deformation and, consequently, a better treatment of axial areas and elimination of the axial defects of the ingot metal.
Simulation of forming operations, particularly using the finite element method, is clearly dependent on the accuracy of the constitutive models. In the last years, several methodologies were developed to improve the a...
Simulation of forming operations, particularly using the finite element method, is clearly dependent on the accuracy of the constitutive models. In the last years, several methodologies were developed to improve the accuracy of constitutive models through parameter identification and calibration methodologies. However, independently of the efficacy of the calibration methods, the accuracy of a constitutive model is always constrained to its predefined mathematical formulation. Today, artificial intelligence (AI), such as Machine-learning (ML) techniques, can be used to overpass these limitations. However, their use in the reproduction of material behaviour was not fully explored.
The dynamics of rotating machinery have been extensively investigated during the past century. To date, longer rotating shafts, higher rotating velocity, higher fluid pressure, and generally high performances are requ...
The dynamics of rotating machinery have been extensively investigated during the past century. To date, longer rotating shafts, higher rotating velocity, higher fluid pressure, and generally high performances are required. For this purpose, a deep understanding and a more accurate modelling of the rotating machinery dynamical behaviour is needed, especially in terms of the resultant vibrations and stability issues. In this paper, a mathematical model was developed for a simple rigid rotor-bearing system using finite element method. Several natural frequencies and corresponding mode shapes of the systems were presented. In order to validate the model, some experimental tests were performed using a small test rig. The response of the system in the frequency domain and the direct orbit of the shaft were plotted as well.
modelling is a portrait of complex natural or real world processes which enhances the knowledge of the mechanisms and provides assistance for prediction. In biology and bio medicine, organ malfunctioning of micro and ...
modelling is a portrait of complex natural or real world processes which enhances the knowledge of the mechanisms and provides assistance for prediction. In biology and bio medicine, organ malfunctioning of micro and macro level living populations can be understood through modelling and it helps to develop different methods to control. This paper considers the mathematical model of two species interaction using Caputo type fractional difference operator. The presence of chaos and its influence are studied in this work. The prey-predator fractional map’s dynamic behaviour is validated experimentally by means of time series, bifurcation diagrams, chaotic and coexisting attractors. Further, adaptive control law is proposed to stabilize the fractional map and a control scheme is introduced to enhance the synchronization of the fractional model. Finally the effectiveness of the theoretical findings are demonstrated with numerical examples.
In the past, various traditional methods used experiments and statistical data to examine and solve the occurred problem and social-environmental issue. However, the traditional method is not suitable for expressing o...
In the past, various traditional methods used experiments and statistical data to examine and solve the occurred problem and social-environmental issue. However, the traditional method is not suitable for expressing or solving the complex dynamics of human environmental crisis (such as the spread of diseases, natural disaster management, social problems, etc.). Therefore, the implementation of computational modelling methods such as Agent-Based Models (ABM) has become an effective technology for solving complex problems arising from the interpretation of humanbehaviour such as human society, environment, and biological systems. Overall, this article will outline the ABM model properties and its applications in the criminology, flood management, and the COVID-19 pandemic fields. In addition, this article will review the limitations that occurred to be overcome in the further development of the ABM model.
modelling and optimization have long been established as a means of achieving efficiency in energy systems also in sustaining the environment. In Nigeria, where environmental pollution have become a challenge, the pro...
modelling and optimization have long been established as a means of achieving efficiency in energy systems also in sustaining the environment. In Nigeria, where environmental pollution have become a challenge, the problem of pollution and safety has become a global concern whereby sustainable power generation systems with zero greenhouse emission will serve as a better way of sustaining the environment. Simulation been a basic similitude tool to real life engineering design enable the engineers to understand the interactive flow process within an operating systems, postulating operation results, designing process systems or optimizing the operating system with optimum accuracy. This tool enables an engineer to establish the geometrical parameters for the actual design of the system. Cyclones, which are widely used as air pollution abatement equipment, are used in processing industries for removal of particulate matter (PM). A 1D2D centrifugal fan power driven cyclone is attached to a batch-type fixed-bed downdraft gasifier was modelled and simulated to determine the behaviour of the gasification products and the optimal efficiency of the cyclone. Applying mathematical modeling and CFD tools to understand the effect of the gas stream on the cyclone performance and a new optimized cyclone geometrical ratios based on the mathematical model was attained. Establishing the cyclone modelling was done by applying the heat content simulation tool (MATLAB-Software package) and using the response surface methodology (RSM) approach. The geometrical parameters in cyclone separators significantly affected the flow field and performance parameters. Analysis of the experimental design informed the researcher on the relationship between the effects of inlet dimensions and the vortex finder diameter on the performance of the cyclone. The cyclone design and simulation of the cyclone has shown that it can effectively remove solid particles from a gas stream (syn-gas). The calculation s
Power system will occur chaotic oscillation when it is exist periodic load disturbances. As for it, the simplified mathematical model of interconnected two- machine second-order power system is established based on th...
Power system will occur chaotic oscillation when it is exist periodic load disturbances. As for it, the simplified mathematical model of interconnected two- machine second-order power system is established based on the modelling and analysis of nonlinear system theory, and the dynamic behaviour of chaotic oscillation in power system is analysed. According to the sliding mode control and fuzzy control theory, the fuzzy-based sliding mode control is proposed, it is also analysed and proved theoretically. Simulations results show that the proposed method can suppress the chaotic oscillation in power system effectively. It not only reduce the convergence time, but also reduced the chattering of the system, and has strong robustness.
human joint angle measurement involves various applications, for example monitoring of spine movement in sagittal and frontal planes, upper limb motion such as shoulder, neck and elbow, as well as lower limb motion su...
human joint angle measurement involves various applications, for example monitoring of spine movement in sagittal and frontal planes, upper limb motion such as shoulder, neck and elbow, as well as lower limb motion such as hip, knee, and ankle. As the range of motions of different human joints are not similar, the output estimation of the designed sensor for these applications need to be carried out prior to sensor development. In this paper, the conceptual design of low-cost plastic optical fibre based on single step index fibre is illustrated, the mathematicalmodelling is explained, and the sensor's hardware assemble is designed using CATIA software, before the estimated sensor output is presented. These results will be used as a reference values for actual optical fibre sensor design in the near future.
human community has outgrown breaking the laws of the nature. This has caused serious threat to the nature and hence to the human community itself. Day to day activities of the man creates different kind of waste mate...
human community has outgrown breaking the laws of the nature. This has caused serious threat to the nature and hence to the human community itself. Day to day activities of the man creates different kind of waste materials. These materials are thrown in the surroundings, which creates unpredictable damage to the environment. The matter of management of waste has prime priority in sustainable development. In this paper we mainly discuss various characteristics of waste management systems such as efficiency, sufficiency and consistency. A waste management system is developmental if it generates employment and income to the country. We develop some mathematical models which to ensure the efficiency and developmental characteristics of the waste management systems.
The paper deals with mathematicalmodelling and experimental investigation of a novel electrothermal oscillator based on Shape Memory Alloys (SMA). The operation of the oscillator is based on a heated by DC electric c...
The paper deals with mathematicalmodelling and experimental investigation of a novel electrothermal oscillator based on Shape Memory Alloys (SMA). The operation of the oscillator is based on a heated by DC electric current SMA wire, mounted with a pre-tension between the free ends of two symmetrically arranged cantilever beams. Crystallographic changes in the SMA wire, consisting in the transition between austenitic and martensitic phases due to the periodic heating and cooling, lead to its intermittent shortening and stretching and thus mechanical and electrical vibrations are generated. The mathematical model of the system is derived using Lagrange-Maxwell formalism, Joule–Lenz law and Newton's law of cooling. Simulation results show two types of periodic motion – the first one with low frequency is due to the temperature variation in the wire and the second one is with much more higher frequency and is due to the mass and elastic properties of the system. Experimental validation of the mathematical model shows its suitability for description of the considered system dynamic behaviour.
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