Application of Memristors in Microwave Passive Circuits

The recent implementation of the fourth fundamental electric circuit element, the memristor, opened new vistas in many fields of engineering applications. In this paper, we explore several RF/microwave passive circuits that might benefit from the memristor salient characteristics. We consider a power divider, coupled resonator bandpass filters, and a low-reflection quasi-Gaussian lowpass filter with lossy elements. We utilize memristors as configurable linear resistors and we propose memristor-based bandpass filters that feature suppression of parasitic frequency pass bands and widening of the desired rejection band. The simulations are performed in the time domain, using LTspice, and the RF/microwave circuits under consideration are modeled by ideal elements available in LTspice

Design and evaluation of an ontology-based tool for generating multiple-choice questions

© 2020 Emerald Publishing Limited. This accepted manuscript is deposited under the Creative Commons Attribution Non-commercial International Licence 4.0 (CC BY-NC 4.0). Any reuse is allowed in accordance with the terms outlined by the licence, here: https://creativecommons.org/licenses/by-nc/4.0/. To reuse the AAM for commercial purposes, permission should be sought by contacting [email protected]: The recent rise in online knowledge repositories and use of formalism for structuring knowledge, such as ontologies, has provided necessary conditions for the emergence of tools for generating knowledge assessment. These tools can be used in a context of interactive computer-assisted assessment (CAA) to provide a cost-effective solution for prompt feedback and increased learner’s engagement. The purpose of this paper is to describe and evaluate a tool developed by the authors, which generates test questions from an arbitrary domain ontology, based on sound pedagogical principles encapsulated in Bloom’s taxonomy. Design/methodology/approach: This paper uses design science as a framework for presenting the research. A total of 5,230 questions were generated from 90 different ontologies and 81 randomly selected questions were evaluated by 8 CAA experts. Data were analysed using descriptive statistics and Kruskal–Wallis test for non-parametric analysis of variance.FindingsIn total, 69 per cent of generated questions were found to be useable for tests and 33 per cent to be of medium to high difficulty. Significant differences in quality of generated questions were found across different ontologies, strategies for generating distractors and Bloom’s question levels: the questions testing application of knowledge and the questions using semantic strategies were perceived to be of the highest quality. Originality/value: The paper extends the current work in the area of automated test generation in three important directions: it introduces an open-source, web-based tool available to other researchers for experimentation purposes; it recommends practical guidelines for development of similar tools; and it proposes a set of criteria and standard format for future evaluation of similar systems.Peer reviewedFinal Accepted Versio

THE MUSCLE CONTRACTION AND THE FORCE PRODUCTION

We study the muscular force during contraction via linear and quadratic approximations of the resistance force. Using theoretical - mechanics arguments, we shall determine the relevant parameters featuring in the equation of motion. This is very important for the determination of the type of training practice which will transform the muscle for various types of dealing with the medium resistance

THE BEHAVIOUR OF MUSCLES IN EXTERNAL INSTANTANEOUS FORCE FIELDS

The purpose of this study is to analyze the behaviour of muscles in an external instantaneous force field. A model is presented which provides a qualitative assessment of what occurs when muscles react to a strong strike or a sudden jerk. In the context of the model, it has been noticed that fine muscles reacted to a strike or jerk differently to massive muscles

"It happened, what's the problem?" and "A guide through the problem" - A model for consideration of ecological issues in chemistry education

In order to improve the ability to apply knowledge of chemistry (acquired in the existing educational system) in real life, the model for consideration of ecological issues was developed and applied in high school. The model consists of a continuous text "It Happened, What's the Problem?" and a test with non-continuous text "A Guide Through the Problem", which were prepared for consideration of the problem of eutrophication. All results obtained (average achievement of 70.9 +/- 14.3 %) showed that the application of the model enabled: understanding of an ecological problem based on scientific representations of the term eutrophication given in the continuous text, realization that pollution of the environment may be directly related to modern life, application of acquired knowledge of chemistry to observe and understand the cause and effect of eutrophication in the environment, to draw a scientific conclusion, and understanding the importance of science and technology discoveries for solving ecological problems. In addition, the model contributed to the development of student's environmental literacy (ecological knowledge and cognitive skills), ability to think critically, and provided possibilities for classroom knowledge to become applicable in real life

The dominant contribution on wet deposition of water-soluble main ions in the South-Eastern Adriatic region

The results of content of water-soluble ions measured in 604 samples of precipitation collected in South-Eastern Adriatic region during 6 years have been analyzed. The HYSPLIT model was used to study the air mass paths. Although the ion concentrations of investigated ions in precipitation of air masses from the continental parts of Europe were significant, the total wet deposition is dominated by precipitation coming over the Mediterranean Sea. The sea salt components are significantly correlated. The correlations between Ca2+ and Mg2+, Ca2+ and SO4 (2-) and Ca2+ and K+ indicate the main terrigeneous ions

Active personal dosemeters in interventional radiology: tests in laboratory conditions and in hospitals

The work package 3 of the ORAMED project, Collaborative Project (2008-11) supported by the European Commission within its seventh Framework Programme, is focused on the optimisation of the use of active personal dosemeters (APDs) in interventional radiology and cardiology (IR/IC). Indeed, a lack of appropriate APD devices is identified for these specific fields. Few devices can detect low-energy X rays (20-100 keV), and none of them are specifically designed for working in pulsed radiation fields. The work presented in this paper consists in studying the behaviour of some selected APDs deemed suitable for application in IR/IC. For this purpose, measurements under laboratory conditions, both with continuous and pulsed X-ray beams, and tests in real conditions on site in different European hospitals were performed. This study highlights the limitations of APDs for this application and the need of improving the APD technology so as to fulfil all needs in the IR/IC fiel