With the importance of renewable energy well-established worldwide, and targets of such energy quantified in many cases, there exists a considerable interest in the assessment of wind and wave devices. While the indiv...
With the importance of renewable energy well-established worldwide, and targets of such energy quantified in many cases, there exists a considerable interest in the assessment of wind and wave devices. While the individual components of these devices are often relatively well understood and the aspects of energy generation well researched, there seems to be a gap in the understanding of these devices as a whole and especially in the field of their dynamic responses under operational conditions. The mathematicalmodelling and estimation of their dynamic responses are more evolved but research directed towards testing of these devices still requires significant attention. Model-free indicators of the dynamic responses of these devices are important since it reflects the as-deployed behaviour of the devices when the exposure conditions are scaled reasonably correctly, along with the structural dimensions. This paper demonstrates how the Hurst exponent of the dynamic responses of a monopile exposed to different exposure conditions in an ocean wave basin can be used as a model-free indicator of various responses. The scaled model is exposed to Froude scaled waves and tested under different exposure conditions. The analysis and interpretation is carried out in a model-free and output-only environment, with only some preliminary ideas regarding the input of the system. The analysis indicates how the Hurst exponent can be an interesting descriptor to compare and contrast various scenarios of dynamic response conditions.
The demand for solar photovoltaic (PV) system is growing rapidly driven by new technology and strong economies of scale. PV systems directly convert solar energy into electricity without release any pollution into the...
The demand for solar photovoltaic (PV) system is growing rapidly driven by new technology and strong economies of scale. PV systems directly convert solar energy into electricity without release any pollution into the environment and deplete natural resources. PV technology has matured and its reliability keeps improving. However, PV system is more expensive to produce than conventional sources of energy due in part to the cost of manufacturing PV devices and in part to the conversion efficiencies of the equipment. Besides, important attention in designing, developing and installing the PV systems is time-consuming. In this paper, we propose a mathematical model to predict the PV systems behaviour and performance by considering the plausible factors. The factors accept in this model are solar irradiance and manufacturers' information for the type of PV panel. A case study at the eastern part of Peninsular Malaysia was conducted to examine the effect of factors on the performance of PV. Through the comparative analysis, the results have a good agreement.
Neurotransmitters play a crucial role in neurological functions. Neural activity is significantly impacted by the balance of neurotransmitters in different parts of the brain. In order to comprehend many complex multi...
Neurotransmitters play a crucial role in neurological functions. Neural activity is significantly impacted by the balance of neurotransmitters in different parts of the brain. In order to comprehend many complex multi-factorial neurological diseases, mathematicalmodelling can be helpful. Neurotransmitter release, diffusion, and intake are studied rigorously nowadays in various computational models of brain disorders. The main focus of this work is on dopamine, a neurotransmitter that plays an important role associated with the brain’s reward system. Dopamine-mediated neurodegenerations like Parkinson’s disease (PD) and Schizophrenia have been studied recently using computational approaches. The current work, presented here uses mathematical models to analyse the impact of dopamine levels on specific brain networks leading to diseases such as PD. In this work, neural dynamics in the normal and parkinsonian states are studied in detail with the help of biologically inspired Basal Ganglia (BG) models. The simulations illustrate the behaviour of BG neurons under altered dopamine levels leading to normal or disease states. An extended study with the inclusion of learning and action selection may also help to model the reinforcement learning capability of the BG network.
Forests are the most important regulator of greenhouse gas balances, being the depositor of most of the carbon in the world. At the same time, forests perform many other functions that are needed both in terms of pres...
Forests are the most important regulator of greenhouse gas balances, being the depositor of most of the carbon in the world. At the same time, forests perform many other functions that are needed both in terms of preserving the integrity of the planet's ecosystem and in the context of human development. Climate change has become a new global challenge, increasingly perceived by society as a whole and a certain part of the scientific and expert community as a source of undoubted danger to the population and material assets accumulated by mankind over the entire period of development. In this paper, we aim to review the studies conducted to date on the problem of ecological end economic modelling of the forestry considering both climatic and institutional factors of its development. The main outcome of our research is the concept of a future mathematical model of imitational type that will help to deeply understand the interactions between economy and ecology of the Russian forestry.
Oral cancer is one of the most commonly known cancer worldwide. Thymoquinone (TQ) an extract from Nigella sativa, has clinically been proven as an anticancer therapeutic agent for oral cancer due to its intrinsic phar...
Oral cancer is one of the most commonly known cancer worldwide. Thymoquinone (TQ) an extract from Nigella sativa, has clinically been proven as an anticancer therapeutic agent for oral cancer due to its intrinsic pharmacological characteristics. Understanding the mechanisms of oral cancer proliferation and death in the presence of TQ is crucial so that the insight of the interaction of cancer cells and TQ can be discovered. Cancer cells in the presence of TQ is subjected to the uncontrolled factors of the environmental noise. Deterministic model is inadequate to explain this behaviour. Herein, a stochastic model is proposed to illustrate the dynamics of HSC-3 oral cancer cell lines in the presence of TQ. The deterministic model is perturbed with the noisy behaviour which then leads to the stochastic model. The model is simulated by using a four-stage stochastic Runge-Kutta (SRK4) method and the kinetic parameters are estimated by using the maximum likelihood estimation (MLE) method. The prediction quality of the model is measured by using root mean square error (RMSE). The low values of RMSE show the best-fit of the stochastic model.
The paper presents a mathematical model and the design details to manufacture a prototype of a smart orthosis for posture correction while sitting on a chair at your office or at home. The global geometry for developi...
The paper presents a mathematical model and the design details to manufacture a prototype of a smart orthosis for posture correction while sitting on a chair at your office or at home. The global geometry for developing the mathematical model was obtained by direct measuring a human 3D model, developed by scanning one of the authors' body and 3D printing it. Based on the mathematical model, the detailed design for the entire product was performed in accordance with the product architecture. The stages of detailed design for the critical systems within the final assembly are also presented in the paper. The posture correction orthosis must be customized for each user, thus, once the design for the critical components has been validated, a parametric design has been generated to facilitate the manufacturing process. The technical solutions are generated and analysed for a vertebral element of the orthosis, representing the critical component of the product. The vertebral element is subject to mechanical stresses, so that a finite element analysis was performed. The geometry of the component and its material were validated by using FEA on the CAD model of the vertebral element. The further work will include research regarding the changes needed for transforming the orthosis into a medical device for spinal column illnesses.
In this paper, we present the results obtained by modelling the users' behaviours in a mixed mode office building in a tropical climate, more exactly in La Réunion. Few specific research studies on comfort in...
In this paper, we present the results obtained by modelling the users' behaviours in a mixed mode office building in a tropical climate, more exactly in La Réunion. Few specific research studies on comfort in tropical climates have been published, and there is little feedback on the users' behaviour in these buildings. In order to improve users' assumptions in the design phase, users' actions on ceiling fans and windows have been measured and analysed. These data have then been modelled by machine learning methods, according to hygrothermal comfort and occupancy. The F1 scores eventually obtained for predicting fan use by random forests, decision trees and Bayesian networks are 99%, 98% and 95% respectively. For windows use, the F1 scores obtained are 92%, 91% and 70%, which demonstrates the ability of the models tested to predict the users' behaviours.
The article deals with the creation of a human tibia 3D model by means of 'Autodesk Revit-2016' PC based on tomogram data. The model was imported into 'Lira- SAPR2013 R4' software system. To assess the...
The article deals with the creation of a human tibia 3D model by means of 'Autodesk Revit-2016' PC based on tomogram data. The model was imported into 'Lira- SAPR2013 R4' software system. To assess the possibility of education and the nature of bone fracture (and their visualization), the Finite Element Analysis (FEA) method was used. The geometric parameters of the BBK model corresponded to the physical parameters of the individual. The compact plate different thickness is modeled by rigidity properties of the finite elements in accordance with the parameters on the roentgenogram. The BBK model included parameters of the outer compact plate and the spongy substance having a more developed structure of the epiphysic region. In the 'Lira-SAPR2013 R4' software system, mathematical modeling of the traumatic effect was carried out and the analysis of the stress-strain state of the finite element model of the tibia was made to assess fracture conditions.
In this article, a performance assessment of the evacuation system is established for educational buildings. Structural and geotechnical information of the building is collected and introduced into a database. A simil...
In this article, a performance assessment of the evacuation system is established for educational buildings. Structural and geotechnical information of the building is collected and introduced into a database. A similar procedure was realized for the information related to the occupants. Using this information, a) the structural fragility and localized collapse were determined and b) the interaction of the person with the partial collapse was established. For the first aspect, nonlinear time history was used, and for the second, the agent-based modeling was applied to recreate the reaction of people that face the micro collapse. Therefore, the important results of this evaluation are: 1) To localize collapsed beans and columns that make inoperable evacuation routes, 2) to localize bottleneck areas that people concentration during evacuation, and 3) quantification of affected people, in terms of persons caught up in the building that cannot evacuate.
Nonlinear elastic models have been widely used to describe the mechanical behaviour of complex materials such as skin. The subject of skin modelling is fairly new and of great importance to fields such as robotics and...
Nonlinear elastic models have been widely used to describe the mechanical behaviour of complex materials such as skin. The subject of skin modelling is fairly new and of great importance to fields such as robotics and the development of skin-like materials to orthopaedics and prosthetics. The present article serves to add to the findings of previous authors and present experimental values gathered using the 'Stick-Slip Experimental Stand' within the Machine Elements and Tribology Department on the tribological aspects regarding friction at very low speeds. The scope of this article is to evaluate the static and kinetic friction coefficients of the human skin in contact with different materials. A total of 5 different materials were tested to find the static and kinetic friction coefficient. The tested materials were steel, bronze, and 3 types of materials found on the inside of working gloves in direct contact with human skin: leather (bovine origin) and 2 types of textiles (cotton and nylon). All tests were performed at 1.8 mm/min, with an initial load of 7.5 Newton and a test time of 1000 seconds. The total distance evaluated was 9.25 mm.
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