Search results for: motivational dynamics

Authors: Etsuo Morishita

Abstract:

This paper presents the project and experiment-based fluid dynamics education in Meisei University, a private institution in Tokyo, Japan. We pay attention not only to the basic engineering courses but also to the practical aspect of engineering experience. So, we prepare courses called the Projects from I to VI. The Projects I and II are designed for the first year, III and IV are designated for the second year, V and VI are prepared for the third year, respectively. Each supervisor is responsible for two of these projects every year. When students take the Project V and VI at the third year, we automatically assume that these students will join the lab of the project for the graduation thesis. We would like to show our experience in the Project I in the summer term, 2016. In this project, we introduce a traction flight vehicle called Cat Flyer. This is a kind of a kite towed by a car for example. This is very similar to parasailing, but flight is possible even on the roads. Experiments in mechanical engineering education are also very important, and we would like to explain our course on centrifugal pump, venture, and orifice. Although these are described in detail in the text books of fluid dynamics, it is still crucial to have practical experiments as a student.

Keywords: aerodynamics, experiment, fluid dynamics, project

Procedia PDF Downloads 258

Authors: T. G. Kassem, A. K. Adunchezor, J. P. Chollom

Abstract:

This paper describes a mathematical model developed to predict the dynamics of Hepatitis B virus (HBV) infection and to evaluate the potential impact of vaccination and treatment on its dynamics. We used a compartmental model expressed by a set of differential equations based on the characteristic of HBV transmission. With these, we find the threshold quantity R0, then find the local asymptotic stability of disease free equilibrium and endemic equilibrium. Furthermore, we find the global stability of the disease free and endemic equilibrium.

Keywords: hepatitis B virus, epidemiology, vaccination, mathematical model

Procedia PDF Downloads 324

Authors: Khaled Suleiman Mohammed Al-Mashrafi

Abstract:

A compositional plume is a fluid flow in a directional channel of finite width in another fluid of different material composition. The study of the dynamics of compositional plumes plays an essential role in many real-life applications like industrial applications (e.g., iron casting), environmental applications (e.g., salt fingers and sea ice), and geophysical applications (e.g., solidification at the inner core boundary (ICB) of the Earth, and mantle plumes). The dynamics of compositional plumes have been investigated experimentally and theoretically. The experimental works observed that the plume flow seems to be stable, although some experiments showed that it can be unstable. At the same time, the theoretical investigations showed that the plume flow is unstable. This is found to be true even if the plume is subject to rotation or/and in the presence of a magnetic field and even if another plume of different composition is also present. It is noticeable that all the theoretical studies on the dynamics of compositional plumes are conducted in unbounded domains. The present work is to investigate theoretically the influence of vertical walls (boundaries) on the dynamics of compositional plumes in the absence/presence of a rotation field. The mathematical model of the dynamics of compositional plumes used the equations of continuity, motion, heat, concentration of light material, and state. It is found that the presence of boundaries has a strong influence on the basic state solution as well as the stability of the plume, particularly when the plume is close to the boundary, but the compositional plume remains unstable.

Keywords: compositional plumes, stability, bounded domain, vertical boundaries

Procedia PDF Downloads 32

Authors: Misagh Faezipour

Abstract:

System dynamics is a systems engineering approach that can help address the complex challenges in different systems. Little is known about how the brain represents people to predict behavior. This work is based on how the brain simulates different personal behavior and responds to them in the case of young children ages one to five. As we know, children’s minds/brains are just as clean as a crystal, and throughout time, in their surroundings, families, and education center, they grow to develop and have different kinds of behavior towards the world and the society they live in. Hence, this work aims to identify how young children respond to various personality behavior and observes their reactions towards them from a system dynamics perspective. We will be exploring the Big Five personality traits in young children. A causal model is developed in support of the system dynamics approach. These models graphically present the factors and factor relationships that contribute to the big five personality traits and provide a better understanding of the entire behavior model. A simulator will be developed that includes a set of causal model factors and factor relationships. The simulator models the behavior of different factors related to personality traits and their impacts and can help make more informed decisions in a risk-free environment.

Keywords: personality traits, systems engineering, system dynamics, causal model, behavior model

Procedia PDF Downloads 96

Authors: Kibbeum Na

Abstract:

Previous gamification research has produced mixed results regarding the effectiveness of gamified learning. One possible explanation for this is that individuals perceive the game elements differently. Cognitive Evaluation Theory posits that external rewards can boost or undermine intrinsic motivation, depending on whether the rewards are perceived as informational or controlling. This research tested the hypothesis that game elements can be perceived as either informational feedback or external reward, and the motivational impact differ accordingly. An experiment was conducted using an educational math puzzle to compare the motivation and performance as a result of different perceived affordances game elements. Participants were primed to perceive the game elements as either informational feedback or external reward, and the duration of an attempt to solve the unsolvable puzzle – amotivation indicator – and the puzzle score – a performance indicator–were measured with the game elements incorporated and then without the game elements. Badges and points were deployed as the main game elements. Results showed that, regardless of priming, a significant decrease in performance occurred when the game elements were removed, whereas the control group who solved non-gamified math puzzles maintained their performance. The undermined performance with gamification removal indicates that learners may perceive some game elements as controlling factors irrespective of the way they are presented. The results of the current study also imply that some game elements are better not being implemented to preserve long-term performance. Further research delving into the extrinsic reward-like nature of game elements and its impact on learning motivation is called for.

Keywords: cognitive Evaluation Theory, game elements, gamification, motivation, motivational affordance, performance

Procedia PDF Downloads 106

Authors: Paul Bayron, Richard Kelso, Rey Chin

Abstract:

Wind tunnel experiments were performed in the KC closed-circuit wind tunnel in the University of Adelaide to study the influence of tip-speed-ratio (

Keywords: hotwire anemometry, wake dynamics, wind tunnel, wind turbines

Procedia PDF Downloads 216

Authors: A. K. Visnuprasad, P. J. Jojo, Reshma Bhaskaran

Abstract:

Computational fluid dynamics (CFD) is used to simulate the distribution of indoor radon concentration in a living room with elevated levels of radon concentration which varies from 22 Bqm-3 to 1533 Bqm-3 in 24 hours. Finite volume method (FVM) was used for the simulation. The simulation results were experimentally validated at 16 points in two horizontal planes (y=1.4m & y=2.0m) using pin-hole dosimeters and at 3 points using scintillation radon monitor (SRM). Passive measurement using pin-hole dosimeters were performed in all seasons. Another simulation was done to find a suitable position for a passive ventilation system for the effective mitigation of radon.

Keywords: indoor radon, computational fluid dynamics, radon flux, ventilation rate, pin-hole dosimeter

Procedia PDF Downloads 413

Authors: David Nagy

Abstract:

This paper exemplifies the influence of the purpose of an aircraft on the aerodynamic properties of its airfoil. In particular, the research takes into consideration two types of aircraft, namely cargo aircraft and military high-speed aircraft and compares their airfoil characteristics using their NACA airfoils as well as computational fluid dynamics. The results show that airfoils of aircraft designed for cargo have a heavier focus on maintaining a large lift force whereas speed-oriented airplanes focus on minimizing the drag force.

Keywords: aerodynamic simulation, aircraft, airfoil, computational fluid dynamics, lift to drag ratio, NACA 64-206, NACA 65-415

Procedia PDF Downloads 388

Authors: Paul C. Njoku, Archana Swati Njoku

Abstract:

The study deals with the development of a mathematical model to characterize the oil production in Nigeria. This is calculated by initiating the dynamics of oil production in million barrels revenue plan cost of oil production in million nairas and unit cost of production from 1974-1982 in the contest of the federal Republic of Nigeria. This country export oil to other countries as well as importing specialized crude. The transport network from origin/destination tij to pairs is taking into account simulation runs, optimization have been considered in this study.

Keywords: mathematical oil model development dynamics, Nigeria, characterization barrels, dynamics of oil production

Procedia PDF Downloads 387

Authors: R. Mohan, V. Jadhav, A. Ahmed, J. Rivas, A. Kelkar

Abstract:

Cementitious materials are an excellent example of a composite material with complex hierarchical features and random features that range from nanometer (nm) to millimeter (mm) scale. Multi-scale modeling of complex material systems requires starting from fundamental building blocks to capture the scale relevant features through associated computational models. In this paper, molecular dynamics (MD) modeling is employed to predict the effect of plasticizer additive on the mechanical properties of key hydrated cement constituent calcium-silicate-hydrate (CSH) at the molecular, nanometer scale level. Due to complexity, still unknown molecular configuration of CSH, a representative configuration widely accepted in the field of mineral Jennite is employed. The effectiveness of the Molecular Dynamics modeling to understand the predictive influence of material chemistry changes based on molecular/nanoscale models is demonstrated.

Keywords: cement composite, mechanical properties, molecular dynamics, plasticizer additives

Procedia PDF Downloads 454

Authors: Nazeef, Suleiman, Umar, Danladi Muhammad, Ja'afar Ali, Zaliha Adamu Umar

Abstract:

The population dynamics of Auchenoglanis occidentalis from the Dadin-Kowa reservoir were studied. Population dynamic parameters such as growth, mortality and recruitment patterns were analyzed using length frequency data over a 12-month period employing FiSAT II software. Findings revealed that LWR (b - constant) = 2.88, K = 0.72 -yr., L∞ = 40.91 cm and Tmax = 3.57 years and Ɵ’ = 3.14. Mortality indices revealed that natural mortality (M = 1.39), fishing mortality (F = 0.22) and exploitation ratio (E = 0.14), Lc/L∞ = 0.48, Emax = 0.64, while Lopt = 26.4 cm. Uni-modal recruitment peak observed with Lm = 27.3 cm. A restocking program is suitable to ensure its continuous existence as it seems to have a low population.

Keywords: fish population dynamics, auchenoglanis occidentalis, FISAT II, natural mortality

Procedia PDF Downloads 46

Authors: G. V. Novikov, V. S. Sivozhelezov, S. S. Kolesnikov, K. V. Shaitan

Abstract:

The study reports about the influence of binding of orthosteric ligands as well as point mutations on the conformational dynamics of β-2-adrenoreceptor. Using molecular dynamics simulation we found that there was a little fraction of active states of the receptor in its apo (ligand free) ensemble corresponded to its constitutive activity. Analysis of MD trajectories indicated that such spontaneous activation of the receptor is accompanied by the motion in intracellular part of its alpha-helices. Thus receptor’s constitutive activity directly results from its conformational dynamics. On the other hand the binding of a full agonist resulted in a significant shift of the initial equilibrium towards its active state. Finally, the binding of the inverse agonist stabilized the receptor in its inactive state. It is likely that the binding of inverse agonists might be a universal way of constitutive activity inhibition in vivo. Our results indicate that ligand binding redistribute pre-existing conformational degrees of freedom (in accordance to the Monod-Wyman-Changeux-Model) of the receptor rather than cause induced fit in it. Therefore, the ensemble of biologically relevant receptor conformations is encoded in its spatial structure, and individual conformations from that ensemble might be used by the cell in conformity with the physiological behaviour.

Keywords: seven-transmembrane receptors, constitutive activity, activation, x-ray crystallography, principal component analysis, molecular dynamics simulation

Procedia PDF Downloads 258

Authors: Sang Ho Lee, Tae Heon Moon, Youn Taik Leem, Kwang Woo Nam

Abstract:

Knowledge and IT inputs to other industrial production have become more important as a key factor for the competitiveness of national and regional economies, such as knowledge economies in smart cities. Knowledge and IT industries lead the industrial innovation and technical (r)evolution through low cost, high efficiency in production, and by creating a new value chain and new production path chains, which is referred as knowledge and IT dynamics. This study aims to investigate the knowledge and IT dynamics in Korea, which are analyzed through the input-output model and structural path analysis. Twenty-eight industries were reclassified into seven categories; Agriculture and Mining, IT manufacture, Non-IT manufacture, Construction, IT-service, Knowledge service, Non-knowledge service to take close look at the knowledge and IT dynamics. Knowledge and IT dynamics were analyzed through the change of input output coefficient and multiplier indices in terms of technical innovation, as well as the changes of the structural paths of the knowledge and IT to other industries in terms of new production value creation from 1985 and 2010. The structural paths of knowledge and IT explain not only that IT foster the generation, circulation and use of knowledge through IT industries and IT-based service, but also that knowledge encourages IT use through creating, sharing and managing knowledge. As a result, this paper found the empirical investigation on the knowledge and IT dynamics of the Korean economy. Knowledge and IT has played an important role regarding the inter-industrial transactional input for production, as well as new industrial creation. The birth of the input-output production path has mostly originated from the knowledge and IT industries, while the death of the input-output production path took place in the traditional industries from 1985 and 2010. The Korean economy has been in transition to a knowledge economy in the Smart City.

Keywords: knowledge and IT industries, input-output model, structural path analysis, dynamics of knowledge and it, knowledge economy, knowledge city and smart city

Procedia PDF Downloads 333

Authors: K. Veluraja

Abstract:

Glycan of glycolipids and glycoproteins is playing a significant role in living systems particularly in molecular recognition processes. Molecular recognition processes are attributed to their occurrence on the surface of the cell, sequential arrangement and type of sugar molecules present in the oligosaccharide structure and glyosidic linkage diversity (glycoinformatics) and conformational diversity (glycoconformatics). Molecular Dynamics Simulation study is a theoretical-cum-computational tool successfully utilized to establish glycoconformatics of glycan. The study on various oligosaccharides of glycan clearly indicates that oligosaccharides do exist in multiple conformational states and these conformational states arise due to the flexibility associated with a glycosidic torsional angle (φ,ψ) . As an example: a single disaccharide structure NeuNacα(2-3) Gal exists in three different conformational states due to the differences in the preferential value of glycosidic torsional angles (φ,ψ). Hence establishing three dimensional structural and conformational models for glycan (cartesian coordinates of every individual atoms of an oligosaccharide structure in a preferred conformation) is quite crucial to understand various molecular recognition processes such as glycan-toxin interaction and glycan-virus interaction. The gycoconformatics models obtained for various glycan through Molecular Dynamics Simulation stored in our 3DSDSCAR (3DSDSCAR.ORG) a public domain database and its utility value in understanding the molecular recognition processes and in drug design venture will be discussed.

Keywords: glycan, glycoconformatics, molecular dynamics simulation, oligosaccharide

Procedia PDF Downloads 137

Authors: Akram Rasheed

Abstract:

Background: Simulation in the health care field has been increasingly used over the last years in the training of resuscitation and life support practices. It has shown the advantage of improving the decision-making and technical skills through deliberate practice and return demonstration. Local Problem: This article reports on the integration of simulation-based training (SBT) in the training program about proper team dynamics and leadership skills during cardiopulmonary resuscitation (CPR) in the intensive care unit (ICU). Method and Intervention: Training of 180 critical care nurses was conducted using SBT between 1st January and 30th 2020. We had conducted 15 workshops, with the integration of SBT using high fidelity manikins and using demonstration and return-demonstration approach to train the nursing staff about proper team dynamics and leadership skills during CPR. Results: After completing the SBT session, all 180 nurses completed the evaluation form. The majority of evaluation items were rated over 95% for the effectiveness of the education; four items were less than 95% (88–94%). Lower rated items considered training and practice time, improved competency, and commitment to apply to learn. The team dynamics SBT was evaluated as an effective means to improve team dynamics and leadership skills during CPR in the intensive care unit (ICU). Conclusion: The use of simulation-based training to improve team dynamics and leadership skills is an effective method for better patient management during CPR. Besides skills competency, closed-loop communication, clear messages, clear roles, and assignments, knowing one’s limitations, knowledge sharing, constructive interventions, re-evaluating and summarizing, and mutual respect are all important concepts that should be considered during team dynamics training. However, participants reported the need for a repeated practice opportunity to build competency.

Keywords: cardiopulmonary resuscitation, high fidelity manikins, simulation-based training, team dynamics

Procedia PDF Downloads 142

Authors: Adam Abate, Elham Rasti, Philip Romero

Abstract:

Beta-glucosidase is the key enzyme component present in cellulase and completes the final step during cellulose hydrolysis by converting the cellobiose to glucose. The regulatory properties of beta-glucosidases are most commonly found for the retaining and inverting enzymes. Hydrolysis of a glycoside typically occurs with general acid and general base assistance from two amino acid side chains, normally glutamic or aspartic acids. In order to obtain more detailed information on the dynamic events origination from the interaction with enzyme active site, we carried out molecular dynamics simulations of beta-glycosidase in protonated state (Glu-H178) and deprotonated state (Glu178). The theoretical models generated from our molecular dynamics simulations complement and advance the structural information currently available, leading to a more detailed understanding of Beta-glycosidase structure and function. This article presents the important role of Asn307 in enzyme activity of beta-glucosidase

Keywords: Beta-glucosidase, GROMACS, molecular dynamics simulation, structural parameters

Procedia PDF Downloads 398

Authors: Eunae Lee, Oh-Kuen Kwon, Ki-Sub Kim, Jeong Won Kang

Abstract:

We investigated the dynamic properties of graphene-nanoribbon (GNR) memory encapsulating graphene-nanoflake (GNF) shuttle in the potential to be applicable as a non-volatile random access memory via molecular dynamics simulations. This work explicitly demonstrates that the GNR encapsulating the GNF shuttle can be applied to nonvolatile memory. The potential well was originated by the increase of the attractive vdW energy between the GNRs when the GNF approached the edges of the GNRs. So the bistable positions were located near the edges of the GNRs. Such a nanoelectromechanical non-volatile memory based on graphene is also applicable to the development of switches, sensors, and quantum computing.

Keywords: graphene nanoribbon, graphene nanoflake, shuttle memory, molecular dynamics

Procedia PDF Downloads 461

Authors: Khachatur V. Nerkararyan, Sergey I. Bozhevolnyi

Abstract:

We investigate relaxation dynamics of a quantum dipole emitter (QDE), e.g., a molecule or quantum dot, located near a metal nanoparticle (MNP) exhibiting a dipolar localized surface plasmon (LSP) resonance at the frequency of the QDE radiative transition. It is shown that under the condition of the QDE-MNP characteristic relaxation time being much shorter than that of the QDE in free-space but much longer than the LSP lifetime. It is also shown that energy dissipation in the QDE-MNP system is relatively weak with the probability of the photon emission being about 0.75, a number which, rather surprisingly, does not explicitly depend on the metal absorption characteristics. The degree of entanglement measured by the concurrency takes the maximum value, while the distances between the QDEs and metal ball approximately are equal.

Keywords: metal nanoparticle, localized surface plasmon, quantum dipole emitter, relaxation dynamics

Procedia PDF Downloads 452

Authors: E. V. Fakhrutdinova, K. R. Maksimova, P. B. Chursin

Abstract:

At the present stage of the society progress the health care is an integral part of both the economic system and social, while in the second case the medicine is a major component of a number of basic and necessary social programs. Since the foundation of the health system are highly qualified health professionals, it is logical proposition that increase of doctor`s professionalism improves the effectiveness of the system as a whole. Professionalism of the doctor is a collection of many components, essential role played by such personal-psychological factors as honesty, willingness and desire to help people, and motivation. A number of researchers consider motivation as an expression of basic human needs that have passed through the “filter” which is a worldview and values learned in the process of socialization by the individual, to commit certain actions designed to achieve the expected result. From this point of view a number of researchers propose the following classification of highly skilled employee’s needs: 1. the need for confirmation the competence (setting goals that meet the professionalism and receipt of positive emotions in their decision), 2. The need for independence (the ability to make their own choices in contentious situations arising in the process carry out specialist functions), 3. The need for ownership (in the case of health care workers, to the profession and accordingly, high in the eyes of the public status of the doctor). Nevertheless, it is important to understand that in a market economy a significant motivator for physicians (both legal and natural persons) is to maximize its own profits. In the case of health professionals duality motivational structure creates an additional contrast, as in the public mind the image of the ideal physician; usually a altruistically minded person thinking is not primarily about their own benefit, and to assist others. In this context, the question of the real motivation of health workers deserves special attention. The survey conducted by the American researcher Harrison Terni for the magazine "Med Tech" in 2010 revealed the opinion of more than 200 medical students starting courses, and the primary motivation in a profession choice is "desire to help people", only 15% said that they want become a doctor, "to earn a lot". From the point of view of most of the classical theories of motivation this trend can be called positive, as intangible incentives are more effective. However, it is likely that over time the opinion of the respondents may change in the direction of mercantile motives. Thus, it is logical to assume that well-designed system of motivation of doctor`s labor should be based on motivational foundations laid during training in higher education.

Keywords: motivation, quality of working life, health system, personal-psychological factors, motivational structure

Procedia PDF Downloads 358

Authors: Jie Ji, Jing Xu, Yuehong Zhuang, Xiangqing Kang, Ying Qian, Ping Zhou, Di Xue

Abstract:

Background: In 2014, there were 28,341 health professionals in Pudong new area of Shanghai and the number per 1000 population was 5.199, 55.55% higher than that in 2006. But it was always less than the average number of health professionals per 1000 population in Shanghai from 2006 to 2014. Therefore, allocation planning for the health professionals in Pudong new area has become a high priority task in order to meet the future demands of health care. In this study, we constructed an objective-based system dynamics model to forecast the number of health professionals in Pudong new area of Shanghai in 2020. Methods: We collected the data from health statistics reports and previous survey of human resources in Pudong new area of Shanghai. Nine experts, who were from health administrative departments, public hospitals and community health service centers, were consulted to estimate the current and future status of nine variables used in the system dynamics model. Based on the objective of the number of health professionals per 1000 population (8.0) in Shanghai for 2020, the system dynamics model for health professionals in Pudong new area of Shanghai was constructed to forecast the number of health professionals needed in Pudong new area in 2020. Results: The system dynamics model for health professionals in Pudong new area of Shanghai was constructed. The model forecasted that there will be 37,330 health professionals (6.433 per 1000 population) in 2020. If the success rate of health professional recruitment changed from 20% to 70%, the number of health professionals per 1000 population would be changed from 5.269 to 6.919. If this rate changed from 20% to 70% and the success rate of building new beds changed from 5% to 30% at the same time, the number of health professionals per 1000 population would be changed from 5.269 to 6.923. Conclusions: The system dynamics model could be used to simulate and forecast the health professionals. But, if there were no significant changes in health policies and management system, the number of health professionals per 1000 population would not reach the objectives in Pudong new area in 2020.

Keywords: allocation planning, forecast, health professional, system dynamics

Procedia PDF Downloads 386

Authors: Arif Ali, Divya Raj Sapkota

Abstract:

In this paper, we explain gravitational attraction as the consequence of the dynamics of four-dimensional bodies and the consequent distortion of space. This approach provides an alternative direction to understand various physical phenomena based on the existence of the fourth spatial dimension. For this interpretation, we formulate the acceleration due to gravity and orbital velocity based on the accelerating expansion of three-dimensional symmetric bodies. It is also shown how distortion in space caused by the dynamics of four-dimensional bodies counterbalances the effect of expansion. We find that the motion of four-dimensional bodies through four-dimensional space leads to gravitational attraction, and the expansion of bodies leads to surface gravity. Thus, dynamics in the fourth spatial dimension provide an alternative explanation to gravity.

Keywords: dimensions, four, gravity, voluceleration

Procedia PDF Downloads 100

Authors: Ali Afaghi, Sehraneh Ghaemi

Abstract:

The coordination of the multi-agent systems has been one of the interesting topic in recent years, because of its potential applications in many branches of science and engineering such as sensor networks, flocking, underwater vehicles and etc. In the most of the related studies, it is assumed that the dynamics of the multi-agent systems are integer-order and linear and the multi-agent systems with the fractional-order nonlinear dynamics are rarely considered. However many phenomena in nature cannot be described within integer-order and linear characteristics. This paper investigates the leader-following consensus problem for a class of nonlinear fractional-order multi-agent systems based on observer-based cooperative control. In the system, the dynamics of each follower and leader are nonlinear. For a multi-agent system with fixed directed topology firstly, an observer-based consensus protocol is proposed based on the relative observer states of neighboring agents. Secondly, based on the property of the stability theory of fractional-order system, some sufficient conditions are presented for the asymptotical stability of the observer-based fractional-order control systems. The proposed method is applied on a five-agent system with the fractional-order nonlinear dynamics and unavailable states. The simulation example shows that the proposed scenario results in the good performance and can be used in many practical applications.

Keywords: fractional-order multi-agent systems, leader-following consensus, nonlinear dynamics, directed graphs

Procedia PDF Downloads 398

Authors: Bao Liu, Maarten Vanierschot, Frank Buysschaert

Abstract:

The present work examines the wake dynamics of a rim-driven thruster (RDT) with Computational Fluid Dynamics (CFD). Unsteady Reynolds-averaged Navier-Stokes (URANS) equations were solved in the commercial solver ANSYS Fluent in combination with the SST k-ω turbulence model. The application of the moving reference frame (MRF) and sliding mesh (SM) approach to handling the rotational movement of the propeller were compared in the transient simulations. Validation and verification of the numerical model was performed to ensure numerical accuracy. Two representative scenarios were considered, i.e., the bollard condition (J=0) and a very light loading condition(J=0.7), respectively. From the results, it’s confirmed that compared to the SM method, the MRF method is not suitable for resolving the unsteady flow features as it only gives the general mean flow but smooths out lots of characteristic details in the flow field. By evaluating the simulation results with the SM technique, the instantaneous wake flow field under both conditions is presented and analyzed, most notably the helical vortex structure. It’s observed from the results that the tip vortices, blade shed vortices, and hub vortices are present in the wake flow field and convect downstream in a highly non-linear way. The shear layer vortices shedding from the duct displayed a strong interaction with the distorted tip vortices in an irregularmanner.

Keywords: computational fluid dynamics, rim-driven thruster, sliding mesh, wake dynamics

Procedia PDF Downloads 260

Authors: Muskaan Sethi, Arnab Banerjee, Bappaditya Manna

Abstract:

The present paper aims to investigate a suitable contact between a wheel rolling over a flexible beam. A Linear Complementary (LCP) based approach has been adopted to simulate the contact dynamics for a rigid wheel traversing over a flexible Euler Bernoulli simply supported beam. The adopted methodology is suitable to incorporate the effect of frictional force acting at the wheel-beam interface. Moreover, the possibility of the generation of a gap between the two bodies has also been considered. The present method is based on a unilateral contact assumption which assumes that no penetration would occur when the two bodies come in contact. This assumption helps to predict the contact between wheels and beams in a more practical sense. The proposed methodology is validated with the previously published results and is found to be in good agreement. Further, this method is applied to simulate the contact between wheels and beams for various railway configurations. Moreover, different parametric studies are conducted to study the contact dynamics between the wheel and beam more thoroughly.

Keywords: contact dynamics, linear complementary problem, railway dynamics, unilateral contact

Procedia PDF Downloads 102

Authors: A. Ishag, E. Witruk, C. Altmayer

Abstract:

Motivation and attitudes are considered as hypothetical psychological constructs in explaining the process of second language learning. Gardner (1985) – who first systematically investigated the motivational factors in second language acquisition – found that L2 achievement is related not only to the individual learner’s linguistic aptitude or general intelligence but also to the learner’s motivation and interest in learning the target language. Traditionally language learning motivation can be divided into two types: integrative motivation – the desire to integrate oneself with the target culture; and instrumental motivation – the desire to learn a language in order to meet a specific language requirement such as for employment. One of the Gardner’s main ideas is that the integrative motivation plays an important role in second language acquisition. It is directly and positively related to second language achievement more than instrumental motivation. However, the significance of integrative motivation reflects a rather controversial set of findings. On the other hand, Students’ attitudes towards the target language, its speakers and the learning context may all play some part in explaining their success in learning a language. Accordingly, the present study aims at exploring the significance of motivational and attitudinal factors in learning foreign languages, namely English and German among Sudanese undergraduate students from a psycholinguistic and interdisciplinary perspective. The sample composed of 221 students from the English and German language departments respectively at the University of Khartoum in Sudan. The results indicate that English language’s learners are instrumentally motivated and that German language’s learners have positive attitudes towards the German language community and culture. Furthermore, there are statistical significant differences in the attitudes toward the two languages due to gender; where female students have more positive attitudes than their male counterparts. However, there are no differences along the variables of academic grade and study level. Finally, the reasons of studying the English or German language have also been indicated.

Keywords: motivation and attitudes, foreign language learning, english language, german language

Procedia PDF Downloads 683

Authors: Hashem Al Argha

Abstract:

Cerebral Aneurysms are the ballooning and defect that occurs in the arteries of the brain. This ballooning might enlarge in size due to mechanical forces and could lead to rupture and death. Computational Fluid Dynamics has been used in the recent years in creating a link between engineering sciences and medical sciences. In this paper, the effects of mechanical forces on cerebral aneurysms will be studied. Results of this study show that mechanical forces could lead to rupture of the aneurysm and could lead to death. High mechanical forces including stresses up to 1.7 MPa could pop aneurysms and lead to a brain hemorrhage.

Keywords: computational fluid dynamics, numerical, aneurysm, mechanical forces

Procedia PDF Downloads 256

Authors: Farhad Ghasemi

Abstract:

Along with transforming the international system into a complex and chaotic system, the fundamental question arises: how can deterrence be reconstructed conceptually and theoretically in this system model? The deterrence system is much more complex today than it was seven decades ago. This article suggests that the perception of deterrence as a linear system is a fundamental mistake because it does not consider the new dynamics of the international system, including network power dynamics. The author aims to improve this point by focusing on complexity and chaos theories, especially their nonlinearity and cascading failure principles. This article proposes that the perception of deterrence as a linear system is a fundamental mistake, as the new dynamics of the surrounding international system do not take into account. The author recognizes deterrence as a nonlinear system and introduces it as a concept in strategic studies.

Keywords: complexity, international system, deterrence, linear deterrence, nonlinear deterrence

Procedia PDF Downloads 142

Authors: Rajinder Pal Kaur, Amit Sharma, Anuj Kumar Sharma, Govind Prasad Sahu

Abstract:

The existence of chaos in the marine ecosystems may cause planktonic blooms, disease outbreaks, extinction of some plankton species, or some complex dynamics in oceans, which can adversely affect the sustainable marine ecosystem. The control of the chaotic plankton-fish dynamics is one of the main motives of marine ecologists. In this paper, we have studied the impact of phytoplankton refuge, zooplankton refuge, and fear effect on the chaotic plankton-fish dynamics incorporating phytoplankton, zooplankton, and fish biomass. The fear of fish predation transfers the unpredictable(chaotic) behavior of the plankton system to a stable orbit. The defense mechanism developed by prey species due to fear of the predator population can also terminate chaos from the given dynamics. Moreover, the impact of external disturbances like seasonality, noise, periodic fluctuations, and time delay on the given chaotic plankton system has also been discussed. We have applied feedback mechanisms to control the complexity of the system through the parameter noise. The non-feedback schemes are implemented to observe the role of seasonal force, periodic fluctuations, and time delay in suppressing the given chaotic system. Analytical results are substantiated by numerical simulation.

Keywords: plankton, chaos, noise, seasonality, fluctuations, fear effect, prey refuge

Procedia PDF Downloads 84

Authors: Dino Carpentras, Alejandro Dinkelberg, Michael Quayle

Abstract:

Opinion dynamics models use an agent-based modeling approach to model people’s opinions. Model's properties are usually explored by testing the two 'degrees of freedom': the interaction rule and the network topology. The latter defines the connection, and thus the possible interaction, among agents. The interaction rule, instead, determines how agents select each other and update their own opinion. Here we show the existence of the third degree of freedom. This can be used for turning one model into each other or to change the model’s output up to 100% of its initial value. Opinion dynamics models represent the evolution of real-world opinions parsimoniously. Thus, it is fundamental to know how real-world opinion (e.g., supporting a candidate) could be turned into a number. Specifically, we want to know if, by choosing a different opinion-to-number transformation, the model’s dynamics would be preserved. This transformation is typically not addressed in opinion dynamics literature. However, it has already been studied in psychometrics, a branch of psychology. In this field, real-world opinions are converted into numbers using abstract objects called 'scales.' These scales can be converted one into the other, in the same way as we convert meters to feet. Thus, in our work, we analyze how this scale transformation may affect opinion dynamics models. We perform our analysis both using mathematical modeling and validating it via agent-based simulations. To distinguish between scale transformation and measurement error, we first analyze the case of perfect scales (i.e., no error or noise). Here we show that a scale transformation may change the model’s dynamics up to a qualitative level. Meaning that a researcher may reach a totally different conclusion, even using the same dataset just by slightly changing the way data are pre-processed. Indeed, we quantify that this effect may alter the model’s output by 100%. By using two models from the standard literature, we show that a scale transformation can transform one model into the other. This transformation is exact, and it holds for every result. Lastly, we also test the case of using real-world data (i.e., finite precision). We perform this test using a 7-points Likert scale, showing how even a small scale change may result in different predictions or a number of opinion clusters. Because of this, we think that scale transformation should be considered as a third-degree of freedom for opinion dynamics. Indeed, its properties have a strong impact both on theoretical models and for their application to real-world data.

Keywords: degrees of freedom, empirical validation, opinion scale, opinion dynamics

Procedia PDF Downloads 155

Authors: Javad Khazaei, Rick Blum

Abstract:

Distributed control is an efficient and flexible approach for coordination of multi-agent systems. One of the main challenges in designing a distributed controller is identifying the governing dynamics of the dynamical systems. Data-driven system identification is currently undergoing a revolution. With the availability of high-fidelity measurements and historical data, model-free identification of dynamical systems can facilitate the control design without tedious modeling of high-dimensional and/or nonlinear systems. This paper develops a distributed control design using consensus theory for linear and nonlinear dynamical systems using sparse identification of system dynamics. Compared with existing consensus designs that heavily rely on knowing the detailed system dynamics, the proposed model-free design can accurately capture the dynamics of the system with available measurements and input data and provide guaranteed performance in consensus and tracking problems. Heterogeneous damped oscillators are chosen as examples of dynamical system for validation purposes.

Keywords: consensus tracking, distributed control, model-free control, sparse identification of dynamical systems

Procedia PDF Downloads 266