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Found 6289 publications

Multi-physics thermal analysis of permanent magnets motors with exterior rotor

Lotfi Abdelhakim

Publication Name: Civil Comp Proceedings

Publication Date: 2015-01-01

Volume: Unknown

Issue: Unknown

Page Range: Unknown

Description:

This paper presents a magneto-thermal analysis of an external-rotor permanent magnet synchronous machine based on finite element method. The model developed can be used to predict the temperature distribution inside the motor during the rated operation. Electromagnetic computation is carried out with the aid of two twodimensional finite-element simulations of the cross-section of the permanent magnet motor [1]. In addition, the magnetic core losses of the stator and rotor are modelled based on the results from the electromagnetic analysis and a post-processing formula based on the loss-separation principle. To analyse the process of heat transfer in an electrical machine, empirical correlations are used to describe the convective heat transfer from the different surfaces of the permanent magnet motor. The heat transfer coefficients are determined using dimensionless numbers and the Nusselt number [2]. After the loss calculation, the temperatures of the machine are calculated using a three-dimensional finite element method. The results obtained from the model are compared with the experimental results from testing the prototype electric motor.

Open Access: Yes

DOI: DOI not available

Design, programming and orchestration of heterogeneous manufacturing systems through VR-powered remote collaboration

Tamás Haidegger Peter Galambos Adam B. Csapo István Marcell Fülöp Péter Zentay Imre J. Rudas Péter Baranyi

Publication Name: Robotics and Computer Integrated Manufacturing

Publication Date: 2015-01-01

Volume: 33

Issue: Unknown

Page Range: 68-77

Description:

Modern manufacturing systems are often composed of a variety of highly customized units and specifically designed manufacturing cells. Optimization of assembly and training of staff requires a series of demo installations and excessive use of costly operational resources. In some cases, components are located at different sites, making the orchestration of the whole system even more difficult. Virtual Reality (VR) collaboration environments offer a solution by enabling high fidelity testing and training of complex manufacturing systems. On the other hand, such platforms are difficult to implement in an engineering perspective, as they are required to provide reliable, standard interfaces towards both robotic components and human operators. The VirCA (Virtual Collaboration Arena) platform is a software framework that supports various means of collaboration through the use of 3D augmented/virtual reality as a communication medium. VirCA offers functions for the high-level interoperability of heterogeneous components in a wide range of domains, spanning from research & development, through remote education to orchestration and management of industrial processes in manufacturing applications. This paper provides an overview of the industrial requirements behind high-fidelity virtual collaboration and demonstrates how the VirCA platform meets these requirements. Use cases are provided to illustrate the usability of the platform.

Open Access: Yes

DOI: 10.1016/j.rcim.2014.08.012

An economic prediction of the finer resolution level wavelet coefficients in electronic structure calculations

János Pipek Szilvia Nagy

Publication Name: Physical Chemistry Chemical Physics

Publication Date: 2015-01-01

Volume: 17

Issue: 47

Page Range: 31558-31565

Description:

In wavelet based electronic structure calculations, introducing a new, finer resolution level is usually an expensive task, this is why often a two-level approximation is used with very fine starting resolution level. This process results in large matrices to calculate with and a large number of coefficients to be stored. In our previous work we have developed an adaptively refined solution scheme that determines the indices, where the refined basis functions are to be included, and later a method for predicting the next, finer resolution coefficients in a very economic way. In the present contribution, we would like to determine whether the method can be applied for predicting not only the first, but also the other, higher resolution level coefficients. Also the energy expectation values of the predicted wave functions are studied, as well as the scaling behaviour of the coefficients in the fine resolution limit.

Open Access: Yes

DOI: 10.1039/c5cp01214g

Efficient power consumption strategies for stationary sensors connected to GSM network

Gábor Paller Peter Szarmes Gábor Élo

Publication Name: Sensornets 2015 4th International Conference on Sensor Networks Proceedings

Publication Date: 2015-01-01

Volume: Unknown

Issue: Unknown

Page Range: 63-68

Description:

The number of large sensor systems are rapidly growing nowadays in many fields. Well-designed Big Data solutions are able to manage the enormous data flow and create real business benefits. One dynamically growing application area is precision farming. It requires robust and energy-efficient sensors, because the devices are placed outdoors, often in harsh conditions, and there is no power outlet in the middle of a corn field. Power efficiency is one of the major themes of the Internet of Things (IoT). According to the IoT vision, embedded sensors send their data to processing units (either located near to the sensor or on some intermediate gateway device or in the cloud) using heterogeneous transport networks. Some sensors employ short-range network like Bluetooth and some gateway device like a tablet. Other sensors directly connect to wide-area networks like cellular networks. This paper will analyse different communication patterns accomplished over GSM network from the viewpoint of the energy consumption of the sensor device with the assumption that the sensor is stationary. The measurements were done using two different GSM modems designed for embedded systems to ensure that the results represent a wider picture and not some implementation property of a particular GSM modem. Recommendations are given about the strategies applications should follow in order to minimize the energy consumption of their GSM subsystems.

Open Access: Yes

DOI: 10.5220/0005262500630068

Simulation of Causal Relations of Stakeholder Management System by Using Fuzzy Cognitive Map Approach - A Comparison of Hungarian and Lithuanian Attitudes

Miklós F. Hatwágner Dalia Susniene Daiva Žostautienė András Torma L. T. Kóczy

Publication Name: Procedia Computer Science

Publication Date: 2015-01-01

Volume: 65

Issue: Unknown

Page Range: 880-890

Description:

Stakeholder Relationship Management Systems (SRMS) describe the general behavior of stakeholder relations at organizations. Knowing the interactions between the drivers of the SRMS helps to improve the efficiency of the whole system. This paper investigates the applicability of Fuzzy Cognitive Maps (FCM) to simulate the system dynamics and the causal connections within it. Previous investigations showed that FCM is a proper tool to analyze these relations and with the help of that the business management process and decision making in projects can be supported. The aim of this paper is to present the results of current simulations made with the help of FCM at Lithuanian and Hungarian organizations and to explain the causes of the identified differences. Beside that the paper investigates the influences of the modification of the threshold function's parameter on the final factor states.

Open Access: Yes

DOI: 10.1016/j.procs.2015.09.047

Laboratory Tests with Liquid Nano-ceramic Thermal Insulation Coating

David Bozsaky

Publication Name: Procedia Engineering

Publication Date: 2015-01-01

Volume: 123

Issue: Unknown

Page Range: 68-75

Description:

Liquid nano-ceramic thermal insulation coatings appeared in the last decades on the market of thermal insulation materials. This paint-on insulation contains microscopic cellular ceramic microspheres. These vacuum-hollow balls were made of on high temperature melted ceramic. Its binding material is a mixture of synthetic rubber and other polymers. After mixing with the raw material with its binder, using brush or vacuum vaporizer can be taken on the surface to be insulated. The special literature of liquid nano-ceramic thermal insulation coatings gives different and contradictory thermodynamic details about this material. According to some sources its thermal conductivity is around 0,001-0,003 W/mK, but other papers publish much higher thermal conductivity values (from 0,01 W/mK to 0,14 W/mK). In the Laboratory of Building Materials and Building Physics at Szechenyi Istvan University (Gyor, Hungary) several thermodynamic test were made with liquid nano-ceramic thermal insulation coatings. On basis of European Standards (EN) the thermal conductivity and water absorption of this material was determined. The relationship between thermal conductivity and water content was analyzed. Experiments were performed with conventional thermal insulation materials with additional ceramic coating on one side, two sides and beside two plates. Results were analyzed in order to prove the low thermal conductivity and heat mirror effect of this material.

Open Access: Yes

DOI: 10.1016/j.proeng.2015.10.059

Analysis of the complex environmental impact on urban trajectories

István Lakatos Tamás Péter Ferenc Szauter

Publication Name: Proceedings of the ASME Design Engineering Technical Conference

Publication Date: 2015-01-01

Volume: 9

Issue: Unknown

Page Range: Unknown

Description:

Modeling traffic processes on large-scale road networks leads to the application of positive non-linear systems, Luenberger (1979). Running profiles can be gained from the applied large-size network model based on previous validations, which are sufficiently complex, complicated and built up by accelerations, decelerations and frequent stops. To develop accelerated methods for analyzing complex environmental impact on urban trajectories Our planned researches on emission encourage the further standardization and beyond that, the bilateral interoperability. According to our goals we point out on the differences, which have to be taken into account in the urban traffic also, and of which the lab measurements may vary. Real processes operate like this, which differ from those applied in laboratories and on roller brake test bench. In reality, however, vehicle emission strongly depends on driving style; moreover, it is also affected by any change in traffic flow. Significant differences can be realized in various regions and countries. The role of the optimal vehicle control is highlighted in every case. The same can be stated of the environmental loads of pollutant emissions and concerning the vehicle and environment dynamic. The detailed analysis introduced above has big impact on further automotive researches as being rapid and applicable for big number of vehicles providing statistical support.

Open Access: Yes

DOI: 10.1115/DETC2015-47077

Identification of supply chains based on input-output data

Tibor Vadvári Peter Varlaki

Publication Name: Periodica Polytechnica Transportation Engineering

Publication Date: 2015-01-01

Volume: 43

Issue: 3

Page Range: 162-167

Description:

The paper focuses on supply chain modeling issues, namely how subspace identification techniques can be used to characterize the strength of relations between certain system parameters. This might be useful when no knowledge about the internal workings or inner structure of the system is available, thus only blackbox like approaches can be utilized. Here let us show how supply chains can be identified and modeled by deterministic linear state space models and how the accuracy of the identified model reflects the relation between certain system parameters.

Open Access: Yes

DOI: 10.3311/PPtr.7931

Multi-Physics thermal analysis of permanent magnets motors with exterior rotor

Lotfi Abdelhakim

Publication Name: Civil Comp Proceedings

Publication Date: 2015-01-01

Volume: 108

Issue: Unknown

Page Range: Unknown

Description:

This paper presents a magneto-thermal analysis of an external-rotor permanent magnet synchronous machine based on finite element method. The model developed can be used to predict the temperature distribution inside the motor during the rated operation. Electromagnetic computation is carried out with the aid of two twodimensional finite-element simulations of the cross-section of the permanent magnet motor [1]. In addition, the magnetic core losses of the stator and rotor are modelled based on the results from the electromagnetic analysis and a post-processing formula based on the loss-separation principle. To analyse the process of heat transfer in an electrical machine, empirical correlations are used to describe the convective heat transfer from the different surfaces of the permanent magnet motor. The heat transfer coefficients are determined using dimensionless numbers and the Nusselt number [2]. After the loss calculation, the temperatures of the machine are calculated using a three-dimensional finite element method. The results obtained from the model are compared with the experimental results from testing the prototype electric motor.

Open Access: Yes

DOI: DOI not available