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Article
Publication date: 1 March 2005

Andrzej Jordan, Jarosław Forenc and Marek Tudruj

To present a new parallel method for solving differential equations that describe transient states in physical systems.

Abstract

Purpose

To present a new parallel method for solving differential equations that describe transient states in physical systems.

Design/methodology/approach

The proposed speculative method first solves a differential equation with a large integration step to determine initial data for parallel computations in sub‐intervals of time, then speculatively computes in parallel solutions in all the sub‐intervals with a smaller integration step and finally composes the final solution from the speculatively computed ones. The basic numerical method applied is the well‐known Runge‐Kutta algorithm.

Findings

The speculative method allows important reduction of the computation time of sequential algorithms. The speed‐up of the speculative method that we propose, as compared to the sequential execution, depends on the number of sub‐intervals that are defined inside the total analysed time interval. The speed‐up increases almost linearly with the number of sub‐intervals. The good accuracy of computations in the presented example was obtained.

Research limitations/implications

The proposed method can be applied to non‐linear systems without discontinuity points and to stable systems (i.e. systems insensitive to the selection of initial conditions).

Practical implications

The method can be especially applied for long‐lasting computations with a slow convergence of state variables values along with the decrease of integration steps.

Originality/value

The paper presents an original parallel method for solving differential equations, which significantly speeds up transient states analysis in physical systems.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 24 no. 1
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 1 September 2004

Andrzej Jordan and Carsten Maple

Discusses a parallel algorithm for the finite‐difference time domain method. In particular, investigates electromagnetic field propagation in two and three dimensions. The…

Abstract

Discusses a parallel algorithm for the finite‐difference time domain method. In particular, investigates electromagnetic field propagation in two and three dimensions. The computational intensity of such problems necessitates the use of multiple processors to realise solutions to interesting problems in a reasonable time. Presents the parallel algorithm with examples, and uses aspects of graph theory to examine the communication overhead of the algorithm in practice. This is achieved by observing the dynamically changing adjacency matrix of the communications graph.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 23 no. 3
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 26 August 2014

Andrzej Zawadzki

The purpose of this paper is to aim to an application of element of the theory of differential geometry for building the state space transformation, linearizing nonlinear…

Abstract

Purpose

The purpose of this paper is to aim to an application of element of the theory of differential geometry for building the state space transformation, linearizing nonlinear dynamic system into a linear form.

Design/methodology/approach

It is assumed that the description of nonlinear electric circuits with concentrated parameters or electromechanical systems is given by nonlinear system of differential equations of first order (state equations). The goal is to find transformation which leads nonlinear state equation (written in one coordinate system) to the linear in the other – sought coordinate system.

Findings

The necessary conditions fulfilled by nonlinear system undergoing linearization process are presented. Numerical solutions of the nonlinear equations of state together with linearized system obtained from direct transformation of the state space are included (transformation input – the state of the nonlinear system).

Originality/value

Application of first order exact differential forms for determining the transformation linearizing the nonlinear state equation. Simple linear models obtained with the use of the linearizing transformation are very useful (mainly because of the known and well-mastered theory of linear systems) in solving of various practical technical problems.

Details

COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, vol. 33 no. 5
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 6 July 2012

Arkadiusz Miaskowski, Bartosz Sawicki and Andrzej Krawczyk

The purpose of this paper is to present the basic ideas of magnetic nanoparticles' usage in the breast cancer treatment, which is called magnetic fluid hyperthermia. The…

Abstract

Purpose

The purpose of this paper is to present the basic ideas of magnetic nanoparticles' usage in the breast cancer treatment, which is called magnetic fluid hyperthermia. The proposed approach offers a relatively simple methodology of energy deposition, allowing an adequate temperature control at the target tissue, in this case a cancerous one. By means of a numerical method the authors aim to investigate two heating effects caused by varying magnetic fields, i.e. to compare the power density heating effects of eddy currents and magnetic nanoparticles.

Design/methodology/approach

In order to numerically investigate the combination of the overheating effect of magnetic nanoparticles and eddy currents, the Finite Element Method solver based on FEniCS project has been prepared. To include the magnetic fluid in the model it has been assumed that power losses in the magnetic nanoparticles are completely converted into heat, according to experimentally developed formula. That formula can be interpreted as the hysteresis losses with regard to the volume of magnetic fluid. Finally, the total power density has been calculated as the product of the sum of power density from eddy currents and hysteresis losses. That methodology has been applied to calculate the effectiveness of magnetic fluid hyperthermia with regard to the female breast phantom.

Findings

The paper presents the methodology which can be used in magnetic fluid hyperthermia therapy planning and Computer Aid Diagnosis (CAD). Furthermore, it is shown how to overcome one of the most serious engineering challenges connected with hyperthermia, i.e. achieving adequate temperature in deep tumors without overheating the body surface.

Practical implications

The obtained results connected with the assessment of eddy currents effect suggest that during hyperthermia treatment the configuration which consists of an exciting coil and human body, plays a curial role. Moreover, the authors believe that these results will help to predict the skin surface overheating that accompanies deep heating. The presented methodology can be used by engineers in the development of Computer Aid Diagnosis systems.

Originality/value

In a given patient's situation a number of choices must be made to determine the parameters of the hyperthermia treatment. These include the need of multiple‐point temperature measurements for accurate and thorough monitoring. Treatment planning will require accurate characterization of the applicator deposition pattern and the tissue parameters, as well as the numerical techniques to predict the resultant heating pattern. The presented paper shows how to overcome these problems from the numerical point of view at least.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 31 no. 4
Type: Research Article
ISSN: 0332-1649

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Book part
Publication date: 4 February 2015

Abstract

Details

Including Learners with Low-Incidence Disabilities
Type: Book
ISBN: 978-1-78441-250-0

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Expert briefing
Publication date: 21 January 2020

They will discuss Russia's growing role in the Middle East, Israeli targeting of Iranian proxies and the implications of the killing of Iranian general Qassem Soleimani…

Details

DOI: 10.1108/OXAN-DB250134

ISSN: 2633-304X

Keywords

Geographic
Topical
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Article
Publication date: 5 April 2021

Agnieszka Kwiek, Cezary Galinski, Krzysztof Bogdański, Jaroslaw Hajduk and Andrzej Tarnowski

According to the study of the space flight market, there is a demand for space suborbital flights including commercial tourist flights. However, one of the challenges is…

Abstract

Purpose

According to the study of the space flight market, there is a demand for space suborbital flights including commercial tourist flights. However, one of the challenges is to design a mission and a vehicle that could offer flights with relatively low G-loads. The project of the rocket-plane in a strake-wing configuration was undertaken to check if such a design could meet the FAA recommendation for this kind of flight. The project concept assumes that the rocket plane is released from a slowly flying carrier plane, then climbs above 100 kilometers above sea level and returns in a glide flight using a vortex lift generated by the strake-wing configuration. Such a mission has to include a flight transition during the release and return phases which might not be comfortable for passengers. Verification if FAA recommendation is fulfilled during these transition maneuvers was the purpose of this study.

Design/methodology/approach

The project was focused on the numerical investigation of a possibility to perform transition maneuvers mentioned above in a passenger-friendly way. The numerical simulations of a full-scale rocket-plane were performed using the simulation and dynamic stability analyzer (SDSA) software package. The influence of an elevator deflection change on flight parameters was investigated in two cases: a transition from the steep descent at high angles of attack to the level glide just after rocket-plane release from the carrier and an analogous transition after re-entry to the atmosphere. In particular, G-loads and G-rates were analyzed.

Findings

As a result, it was found that the values of these parameters satisfied the specific requirements during the separation and transition from a steep descent to gliding. They would be acceptable for an average passenger.

Research limitations/implications

To verify the modeling approach, a flight test campaign was performed. During the experiment, a rocket-plane scaled model was released from the RC model helicopter. The rocket-plane model was geometrically similar only. Froude scales were not applied because they would cause excessive technical complications. Therefore, a separate simulation of the experiment with the application of the scaled model was performed in the SDSA software package. Results of this simulation appeared to be comparable to flight test results so it can be concluded that results for the full-scale rocket-plane simulation are also realistic.

Practical implications

It was proven that the rocket-plane in a strake-wing configuration could meet the FAA recommendation concerning G-loads and G rates during suborbital flight. Moreover, it was proven that the SDSA software package could be applied successfully to simulate flight characteristics of airplanes flying at angles of attack not only lower than stall angles but also greater than stall angles.

Social implications

The application of rocket-planes in a strake-wing configuration could make suborbital tourist flights more popular, thus facilitating the development of manned space flights and contributing to their cost reduction. That is why it was so important to prove that they could meet the FAA recommendation for this kind of service.

Originality/value

The original design of the rocket plane was analyzed. It is equipped with an optimized strake wing and is controlled with oblique, all moving, wingtip plates. Its post-stall flight characteristics were simulated with the application of the SDSA software package which was previously validated only for angles of attack smaller than stall angle. Therefore, experimental validation was necessary. However, because of excessive technical problems caused by the application of Froude scales it was not possible to perform a conventional test with a dynamically scaled model. Therefore, the geometrically scaled model was built and flight tested. Then a separate simulation of the experiment with the application of this model was performed. Results of this separate simulation were compared with the results of the flight test. This comparison allowed to draw the conclusion on the applicability of the SDSA software for post-stall analyzes and, indirectly, on the applicability of the proposed rocket-plane for tourist suborbital flights. This approach to the experimental verification of numerical simulations is quite unique. Finally, a quite original method of the model launching during flight test experiment was applied.

Details

Aircraft Engineering and Aerospace Technology, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 1748-8842

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Article
Publication date: 7 June 2019

Jakub Krzeminski, Bartosz Blicharz, Andrzej Skalski, Grzegorz Wroblewski, Małgorzata Jakubowska and Marcin Sloma

Despite almost limitless possibilities of rapid prototyping, the idea of 3D printed fully functional electronic device still has not been fulfilled – the missing point is…

Abstract

Purpose

Despite almost limitless possibilities of rapid prototyping, the idea of 3D printed fully functional electronic device still has not been fulfilled – the missing point is a highly conductive material suitable for this technique. The purpose of this paper is to present the usage of the photonic curing process for sintering highly conductive paths printed on the polymer substrate.

Design/methodology/approach

This paper evaluates two photonic curing processes for the conductive network formulation during the additive manufacturing process. Along with the xenon flash sintering for aerosol jet-printed paths, this paper examines rapid infrared sintering for thick-film and direct write techniques.

Findings

This paper proves that the combination of fused deposition modeling, aerosol jet printing or paste deposition, along with photonic sintering, is suitable to obtain elements with low resistivity of 3,75·10−8 Ωm. Presented outcomes suggest the solution for fabrication of the structural electronics systems for daily-use applications.

Originality/value

The combination of fused deposition modelling (FDM) and aerosol jet printing or paste deposition used with photonic sintering process can fill the missing point for highly conductive materials for structural electronics.

Details

Circuit World, vol. 45 no. 1
Type: Research Article
ISSN: 0305-6120

Keywords

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Book part
Publication date: 4 February 2015

Abstract

Details

Including Learners with Low-Incidence Disabilities
Type: Book
ISBN: 978-1-78441-250-0

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Article
Publication date: 30 July 2020

Christian Nold

The purpose of this paper is to articulate an ontological anarchist approach for an engaged post-human politics and present insurrection training as a pragmatic tool for…

Abstract

Purpose

The purpose of this paper is to articulate an ontological anarchist approach for an engaged post-human politics and present insurrection training as a pragmatic tool for researchers to directly transform the world.

Design/methodology/approach

The paper analyses how post-humanism has been criticised for dissolving political agency. It shows that this is due to the way post-humanism has been framed as sensitising and including non-humans into liberal politics. Instead, the paper examines anarchist-influenced post-humanism and combines this with the notion of multiple ontologies and ontological interventions. The paper presents the notion of insurrection training as offering the possibility for researchers to become emotionally sensitised to ontological difference. A case study of the “Seeds of Hope East Timor Ploughshares action” (1996) is used to illustrate what insurrection training and ontological interventions look like in practice. Finally, the paper makes suggestions as to how post-human researchers can apply this approach in their everyday lives.

Findings

The paper suggests that beyond a liberal framing of post-humanism as inclusion, there is also an ontological anarchist post-humanism that can support transformative impacts in the world. This form of post-humanism offers specificity of intervention and reflexive training practices. Insurrection training can offer new possibilities for post-humanist researchers: experience ontological difference, de-trivialise the everyday, connect to social movements, make post-human politics “doable” and offer “direct” change.

Originality/value

The paper addresses discussions that claim post-humanism is disabling political change. Its contribution is to map an anarchist post-humanism and extend this with concepts of multiple ontologies. It proposes the notion of insurrection training which places attention on the role of the researcher as an active agent that needs to be sensitised to ontological difference to carry out interventions. A case study of direct action illustrates what ontological intervention and insurrection training look like in practice. The case study suggests that insurrection training is an everyday performative practice that integrates and negotiates the personal, material and political. Finally, the paper suggests how researchers can adopt such an approach in their everyday lives.

Details

International Journal of Sociology and Social Policy, vol. 41 no. 3/4
Type: Research Article
ISSN: 0144-333X

Keywords

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