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Found 6278 publications
Modelling of an electroactive polymer actuator
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
Towards the synthesis of reliable and resilient complex networks
Publication Name: Current Opinion in Chemical Engineering
Publication Date: 2025-09-01
Volume: 49
Issue: Unknown
Page Range: Unknown
Description:
Process synthesis methodologies have traditionally focused on optimizing the economic criteria. However, owing to the complexity of real systems, external factors, such as expected or unexpected events or disturbances, negatively affect the performance of optimal networks. In this context, it becomes essential to consider the effect of such events on the performance of the network in the early design stages. This work presents a comprehensive review of the contributions related to this relevant topic, focusing on two widely utilized indicators: reliability and resilience. Reliability focuses on the probability of system failures due to disturbances, and resilience analyzes the behavior of the system after disturbances and its capacity to recover over time. Relevant contributions are reviewed, which present deterministic and stochastic methods to estimate these indicators, with a special focus on the design phase. Moreover, this work also presents a perspective on using machine learning methods on complex systems datasets as an emerging direction for enhancing the estimation of these properties. This contribution highlights recent advancements in this field and emphasizes the relevance of resilience and reliability as key metrics for developing safer processes with improved operability.
Open Access: Yes
Potential cardiovascular benefit of optimized lipid-lowering and antiplatelet therapy in patients with acute coronary syndrome - A simulation analysis
Publication Name: Orvosi Hetilap
Publication Date: 2024-11-03
Volume: 165
Issue: 44
Page Range: 1746-1752
Description:
Introduction: Lipid lowering therapy - despite the accumulated clinical trial evidence behind it and its significant preventive role reflected in the guidelines - does not have its rightful place in the value system of patients or doctors, there is a great gap between practice and principles. Objective: In order to increase the prestige of lipid-lowering therapy, the potential benefit of lowering LDL cholesterol was compared with antiplatelet therapy, which is generally more accepted. Method: We processed the data of 531 patients of the Bekes County Central Hospital Pandy Kalman Branch in Gyula who underwent percutaneous coronary intervention for acute coronary syndrome for one year starting on April 1, 2020. A simulation study was conducted during which, based on the results of large clinical studies, the cardiovascular prevention effect of optimal lipid reduction and platelet aggregation inhibition for one year was estimated. Results: In all 531 patients treated for acute coronary syndrome, if LDL cholesterol levels had remained at the mean level of 3.37 mmol/L found at admission, 59 major cardiovascular events could have occurred within one year after the index event. If LDL-cholesterol levels were to be reduced to 1.4 mmol/L, which is the very high-risk target value in the lipid recommendations of the European Society of Cardiology, the number of events would be 13, and 16 if the theoretical, very low, non-target value of 0.5 mmol/L was reached. Lowering LDL cholesterol levels is therefore expected to avoid 13 and 16 major cardiovascular events, respectively. If aspirin alone was given for antiplatelet aggregation, 14 events could be prevented over a year, 17 events could be prevented using aspirin and clopidogrel combination, and 20 events with aspirin and prasugrel or aspirin and ticagrelor. Discussion: Based on the low rates of achieving LDL cholesterol targets, there is a considerable potential for optimizing lipid-lowering treatment worldwide. In patients with acute coronary syndrome, one of the most vulnerable patient groups in cardiology practice, the study results suggest that lipid reduction and platelet aggregation inhibition could achieve a similar reduction in the number of major cardiovascular events. Conclusion: The simulation study confirms the comparable cardiovascular benefit of the two interventions. Since the attainment rate of LDL cholesterol targets set in the guidelines is very poor - with physicians' therapeutic inertia playing a major role -, we hope our findings will convince colleagues that more attention should be paid to more optimal lipid reduction.
Open Access: Yes
Hierarchical-interpolative fuzzy system construction by genetic and bacterial memetic programming approaches
Publication Name: International Journal of Uncertainty Fuzziness and Knowldege Based Systems
Publication Date: 2012-01-01
Volume: 20
Issue: SUPPL. 2
Page Range: 105-131
Description:
In this paper a family of new methods are proposed for constructing hierarchical-interpolative fuzzy rule bases in the frame of a fuzzy rule based supervised machine learning system modeling black box systems defined by input-output pairs. The resulting hierarchical rule base is constructed by using structure building pure evolutionary and memetic techniques, namely, Genetic and Bacterial Programming Algorithms and their memetic variants containing local search steps. Applying hierarchical-interpolative fuzzy rule bases is a rather efficient way of reducing the complexity of knowledge bases, whereas evolutionary methods (including memetic techniques) ensure a relatively fast convergence in the learning process. As it is presented in the paper, by applying a newly proposed representation schema these approaches can be combined to form hierarchical-interpolative machine learning systems. © 2012 World Scientific Publishing Company.
Open Access: Yes
Mechanistic and comparative laboratory assessment of lime dosage and uniaxial geogrid on the strength and durability of classified lateritic subgrade
Publication Name: Scientific Reports
Publication Date: 2025-12-01
Volume: 15
Issue: 1
Page Range: Unknown
Description:
This study presents a mechanistic and comparative laboratory assessment of lime stabilization and uniaxial geogrid reinforcement, applied independently and in combination, to improve the engineering performance of a classified A-7-6 (CL–ML) lateritic subgrade from Ogun State, Nigeria. The objective was to evaluate the effect of lime dosage and geogrid inclusion on the short- and long-term California Bearing Ratio (CBR), Unconfined Compressive Strength (UCS), and Resilient Modulus (MR), and to test the hypothesis that chemical and mechanical stabilization mechanisms act synergistically to enhance stiffness and durability. Quicklime (CaO > 90%) was added at 2–8% by dry weight, while the geogrid used was uniaxial polypropylene with an aperture size of 30 mm and tensile strength of 22 kN/m. Specimens were prepared by mixing, compacting, and curing at 25 ± 2 °C and 95 ± 2% RH for 7, 14, and 28 days, then tested according to ASTM and AASHTO standards. Each condition was replicated thrice, and the data were analyzed using one-way ANOVA (p < 0.05). Results showed that lime treatment reduced the plasticity index from 30 ± 1.2 to 6 ± 0.5%, increased UCS from 300 ± 15 to 950 ± 40 kPa and improved soaked CBR from 23 ± 1.1 to 57.5 ± 2.3% after 28 days. Single and double geogrid layers enhanced soaked CBR to 33 ± 1.4% and 43 ± 1.7%, respectively, with negligible strength loss after three moisture cycles, confirming durability under wetting–drying conditions. Combined lime–geogrid stabilization achieved the highest performance, with CBR > 65%, MR > 90 MPa, and UCS > 1.0 MPa, exceeding AASHTO subgrade requirements. The findings demonstrate that lime primarily enhances chemical bonding, whereas geogrid reinforcement improves mechanical confinement; their combination offers a durable, cost-effective, and low-carbon alternative to conventional cement stabilization for tropical lateritic subgrades.
Open Access: Yes
Formation control of quadrotor helicopters with guaranteed collision avoidance via safe path
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
Developing sample holders for measuring shielding effectiveness of thin layers on compound semiconductor substrates
Publication Name: Progress in Electromagnetics Research Symposium
Publication Date: 2011-12-26
Volume: Unknown
Issue: Unknown
Page Range: 1637-1641
Description:
Wavelet or multiresolution analysis (MRA) is widely applied in advanced data compression algorithms, solving differential equations, and some approaches have already applied this technique in describing electromagnetic fields. The main advantage of the application of MRA is its adaptivity and flexibility. Since the details of the electromagnetic field are not distributed equally over different parts of the system (i.e., the description of some parts need finer details, while others are easily represented at low resolution level), locally different resolution levels can be applied. Wavelet based adaptive solution possibilities of differential equations of electromagnetic field are investigated in the followings. The adaptivity of the method means in this case, that the refinement level of the solution can be increased locally, if the accuracy needs it, during the calculations. The applicability of the eigenvalue-type differential equation solving method is illustrated by solution of microwave wave-equations of cavity resonators.
Open Access: Yes
DOI: DOI not available
Forecasting Western Corn Rootworm (Diabrotica virgifera virgifera LeConte) Density and Non-Chemical Control of Larvae: A Practical Review
Publication Name: Agriculture Switzerland
Publication Date: 2024-11-01
Volume: 14
Issue: 11
Page Range: Unknown
Description:
The western corn rootworm (WCR) (Diabrotica virgifera virgifera LeConte; Chrysomelidae) is one of the most significant maize pests in Europe, with farmers spending a substantial amount (approximately 140 EUR) on its control. In the context of climate change, WCRs could pose an even greater threat to EU maize production, particularly as the European Union continues to withdraw an increasing number of effective yet environmentally harmful active agents. Biological control methods have now emerged to the forefront in creating sustainable agriculture. In this review, we carried out an extensive literature analysis on methods for forecasting WCRs and evaluated the practical applicability of the latest non-chemical control methods targeting its larvae. Effective forecasting is essential for successful pest management, enabling informed planning and the selection of the most suitable control methods. Several traditional predicting techniques remain in use today, but recent advancements have introduced modern electronic forecasting units combined with sensor-equipped pheromone and colour traps, as well as thermal sum calculations. Research has demonstrated that crop rotation is one of the most effective methods for controlling WCR larvae. Biological agents, such as entomopathogenic fungi (Beauveria bossiana and Mettarrhyzum anasoplia), entomopathogenic nematodes (Heterorhabditis bacteriophora), and botanical insecticides such as azadirachtin can significantly reduce larval populations and root damage, thereby maintaining infestation levels below the economic threshold. Genetically modified maize plants that produce specific toxins, along with conventional breeding efforts to increase root system regeneration, are also promising tools for the sustainable management of this pest. This review summarizes the solutions for prediction of western corn rootworm infestations and non-chemical control of its larvae. Accurate forecasting methods provide a clear picture of infestation levels in a given area, enabling precisely targeted control measures. In all cases, the control should be directed primarily against the larvae, thereby reducing root damage and reducing the size of the emerging imago population. This review demonstrates that biological control methods targeting larvae can be as effective as pesticides, supporting sustainable pest management.
Open Access: Yes
The response of prion genic variation to selection for scrapie resistance in Hungarian indigenous sheep breeds
Publication Name: Acta Veterinaria Hungarica
Publication Date: 2018-01-01
Volume: 66
Issue: 4
Page Range: 562-572
Description:
The authors studied the present status of Hungarian indigenous sheep breeds based on the genetic background of scrapie resistance. The aim of this investigation was to estimate the relative frequency of prion haplotypes, genotypes and risk categories, as well as to reveal the efficiency of the scrapie eradication programme achieved over the last decade. A novel approach in the characterisation of prion by using its genic variation was also implemented. The authors established that the proportion of deleterious sites (%) can be a useful indicator of the eradication programme. Based on a large sample size, it was confirmed that the scrapie resistance of the Cikta breed is low, and the classification of this breed according to risk category has not improved. However, the frequent genotype ARQ and risk category 3 can also be considered characteristic of the breed. The careful use of these genotypes is permitted and will contribute to the maintenance of breed diversity. The response of prion genic variation to selection for scrapie resistance in the other breeds (Tsigai, Milking Tsigai, White Racka, Black Racka and Gyimes Racka) was definitely successful.
Open Access: Yes
DOI: 10.1556/004.2018.050
