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Found 6289 publications

Effect of biodiesel-derived by-product on the germination of common ragweed (Ambrosia artemisiifolia L.) in pot experiments

No authors available

Publication Name: Journal of Landscape Ecology

Publication Date: 2012-01-01

Volume: 10

Issue: 2

Page Range: 341-349

Description:

The effect of biodiesel-derived by-product (SZO = soap-like emulsion) from rape oil was examined on the germination of common ragweed (Ambrosia artemisiifolia L.) achenes in pot experiments. Soils were treated in three different doses: 2500, 5000 and 10000 liter/ha, applied in proportion to the surface area of the pots. Control soil was moistened with the same amount of tap water. Fifty ragweed achenes were sown into each pot, then the pots were placed in a refrigerator for cold treatment (35 days, +7 °C). Following cold treatment the pots were placed in an unheated greenhouse and the germination of ragweed achenes were monitored for 40 days. Common ragweed seedlings emerged from soils of each treatment including the control, but their rate of germination differed. The highest number of seedlings appeared in the control pots (51.5%), whereas the lowest number was observed in the 2500 l/ha dose pots (33.0%). Order of the treatments according to increasing germination succes was the following: 2500 < 10000 < 5000 < control. Germination rate in treatments 2500 l/ha and 10000 l/ha was significantly lower than it was detected in the control. SZO dose of 5000 l/ha resulted intermediate germination rate of ragweed achenes, that did not differ significantly from any other treatments. Based on the results, the studied biodiesel-derived by-product can potentially be used in weed control. For its appropriate use, the effective chemical components of the SZO should be identified. Further studies needed to determine the optimal dose applicable in field management and to investigate the potential effect of SZO on the germination of cultivated species.

Open Access: No

DOI: DOI not available

Searching for a nonlinear ODE model of vehicle crash with genetic optimization

Miklós F. Hatwágner István Harmati András Horváth

Publication Name: Saci 2012 7th IEEE International Symposium on Applied Computational Intelligence and Informatics Proceedings

Publication Date: 2012-01-01

Volume: Unknown

Issue: Unknown

Page Range: 131-136

Description:

Vehicle crash is a very complex process, which can be modelled in details using the finite element method (FEM), but a simple, quasi-heuristic model with a limited number of parameters is often more beneficial. In this paper we propose a relatively simple dynamic model for deformation and force during a frontal collision process, which has very similar behavior to the experimental data. A genetic-type optimization of model parameters is executed on three car crash experimental data sets. ©2012 IEEE.

Open Access: Yes

DOI: 10.1109/saci.2012.6249990

Molecular dynamics simulation of carbon nanostructures: The C60 buckminsterfullerene

Ibolya Zsoldos István László

Publication Name: Physica Status Solidi B Basic Research

Publication Date: 2012-01-01

Volume: 249

Issue: 12

Page Range: 2616-2619

Description:

Molecular dynamics calculations can reveal the physical and chemical properties of various carbon nanostructures or can help to devise the possible formation pathways. In our days the most well-known carbon nanostructures are the fullerenes, the nanotubes, and the graphene. The fullerenes and nanotubes can be thought of as being formed from graphene sheets, i.e., single layers of carbon atoms arranged in a honeycomb lattice. Usually the nature does not follow the mathematical constructions. Although the first time the C60 and the C70 were produced by laser irradiated graphite, the fullerene formation theories are based on various fragments of carbon chains and networks of pentagonal and hexagonal rings. In the present article various formation pathways for the buckminsterfullerene C60 molecule will be presented. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Open Access: Yes

DOI: 10.1002/pssb.201200125

Error estimation of wavelet based modeling of electromagnetic waves in waveguides and resonators

András Fehér János Pipek Szilvia Nagy

Publication Name: 2nd Middle East Conference on Antennas and Propagation Mecap 2013

Publication Date: 2012-01-01

Volume: Unknown

Issue: Unknown

Page Range: Unknown

Description:

Wavelets provide an effective toolbox for solving differential equations by representing the continuous functions by their wavelet expansion coefficients and the corresponding differential equations by discrete matrix equations. The wavelet basis functions are organized into resolution levels of different frequency terms at different locations, and the main advantage of the wavelet expansion representation is that the resolution level can be different at different locations, if the solution function contains higher frequency terms in one place and restricted to lower frequencies at other places. Wavelet based differential equation solving methods can be adaptive, it is possible to refine the solution locally, if the precision is not sufficient at some regions. In the present work a simple method for estimating the next resolution level wavelet coefficients is presented. Predicting the approximate value of these coefficients makes it possible to select the minimal set of wavelet basis functions for the next resolution level solution in a computationally economic way, or in the last resolution levels it can substitute the next level solution of the matrix equation. © 2012 IEEE.

Open Access: Yes

DOI: 10.1109/MECAP.2012.6618193

Towards the modelling of the fault tolerance mechanism of the PIM-SM multicast routing protocol in an IPTV environment

István Derka Gábor Lencse

Publication Name: Esm 2012 2012 European Simulation and Modelling Conference Modelling and Simulation 2012

Publication Date: 2012-01-01

Volume: Unknown

Issue: Unknown

Page Range: 152-156

Description:

The fault tolerance mechanism of the PIM-SM IP multicast routing protocol is investigated in order to be able to model it. The analysis is done by playing different fault scenarios on a mesh topology multicast test network built up by XORP routers in a virtualized environment. Different parameters of the PIM-SM and the OSPF protocols are examined if they influence and how they influence the outage time of an IPTV service. The results of the experiments provide important factors for building a formal model of the service outage time of an IPTV service. © 2012 EUROSIS-ETI.

Open Access: Yes

DOI: DOI not available

The sociodemographic obstacles to participating in lifelong learning across Europe

Péter Róbert

Publication Name: Lifelong Learning in Europe Equity and Efficiency in the Balance

Publication Date: 2012-01-01

Volume: Unknown

Issue: Unknown

Page Range: 87-102

Description:

No description provided

Open Access: Yes

DOI: DOI not available

Modelling of an electroactive polymer actuator

Ákos Aczél

Publication Name: Procedia Engineering

Publication Date: 2012-01-01

Volume: 48

Issue: Unknown

Page Range: 1-9

Description:

The aim of this paper is to build a model of an electroactive polymer actuator when external electric field is applied. Materials whose rheological properties can be varied by electric excitation are called electroactive materials. The behavior of these rubberlike media is commonly investigated in two different ways. Brigadnov, Dorfmann, Bustamante, Ogden and others describe the coupled problem of finite deformation of the continua in electromagnetic field by taking into account all the electromagnetic phenomena. Pelrine, Kornbluh, Sommer-Larsen and others present a phenomenological description. Our aim is to form a bridge between these two points of view by neglecting those terms of the governing and transformation equations that are smaller than other contributions by several orders of magnitude. First, those equations are presented that govern the finite deformation and the electromagnetic phenomena inside the material. After that, those estimations will be taken that show the order of magnitude of the different contributions to the so-called effective fields. Finally, the model of the EAP actuator under periodically changing electric field will be presented. Because of the periodically changing finite deformation of the actuator, the electromagnetic phenomena must be investigated in the rest frames fixed to every single point of the material body. The electromagnetic field-variables can be converted into the laboratory frame by the slow speed approximation of the Lorentz transformation. For the special case of thin electroactive polymer actuators, one can find that the velocity dependent contributions are smaller by ten orders of magnitude in the electric field transformation, and by five orders of magnitude in the magnetic field transformation equations. On the other hand, none of the terms of the effective current can be neglected, because they can be of the same order of magnitude as the free current. © 2012 Published by Elsevier Ltd.

Open Access: Yes

DOI: 10.1016/j.proeng.2012.09.477

Formation control of quadrotor helicopters with guaranteed collision avoidance via safe path

Gergely Regula Bela Lantos

Publication Name: Periodica Polytechnica Electrical Engineering and Computer Science

Publication Date: 2012-01-01

Volume: 56

Issue: 4

Page Range: 113-124

Description:

In this article we propose a hierarchical control structure for multi-agent systems. The main objective is to perform formation change manoeuvres, with guaranteed safe distance between each two vehicles throughout the whole mission. The key components that ensure safety are a robust control algorithm that is capable of stabilising the group of vehicles in a desired formation and a higher level path generation method that provides safe paths for all the vehicles, based on graph theoretic considerations. The method can effciently handle a large group of any type of vehicles. In the article we focus on the control of quadrotor UAVs, thus the results are illustrated in 4D on a group of such vehicles.

Open Access: Yes

DOI: 10.3311/PPee.7080

Identity and soccer in Corsica

Róbert Győri Szabó

Publication Name: Soccer and Society

Publication Date: 2012-01-01

Volume: 13

Issue: 1

Page Range: 36-55

Description:

For decades Corsica could be characterized as an underdeveloped, politically unstable region ridden with violence. The 'Corsican Question' is a complex phenomenon, created over time as a result of political conflict, social tension and economic maladies. Despite the establishment of administrative autonomy in 1991 and a slow transformation within the French state, coupled with new efforts for institutional reform in order to develop and strengthen Corsica's political autonomy, a successful resolution of conflict in Corsica still remains quite illusory. The most popular sport in the world could be a weapon in the hands of national or ethnic minorities against the majority nation living on the island and against the state ruled by that nation. The Corsican example points up the important connection between football, politics and the question of nations and nationalities across the world. The essay examines how soccer has been used by the Corsican minority as a field of social protest, a stage for demonstrating distinctive identity. Local football is a mirror which reflects the various unresolved questions of the difficult and complex Corsican situation - Corsican identity, relations between the island and the French state, and so on. While Corsican football and the two major Corsican clubs might not ever achieve fame or a strong position in Europe, football will remain one of the most important expressions of Corsican national identity. © 2012 Copyright Taylor and Francis Group, LLC.

Open Access: Yes

DOI: 10.1080/14660970.2012.627166