Lower secondary school students' attitudes toward computer-supported laboratory exercisesAndreja Špernjak
, Miro Puhek
, Andrej Šorgo
, 2010, original scientific article
Abstract: In Science teaching laboratory work is recognized as one of the cornerstones. In school science laboratory work computers can be used as computer supported laboratory (real) and as virtual laboratory. In the first case "real" laboratories involve bench top experiments utilizing data acquisition systems while "virtual" laboratory entails interactive simulations and animations. Lower secondary school students in age between 11 and 15 performed three laboratory exercises (Activity of yeast, Gas exchange in breathing, Heart rate) as classic, computer-supported and virtual laboratory. As a result of testing we know that all three methods are suitable even for younger students. When they were asked which method they liked the most, their first choice was computer-supported laboratory, followed by classic laboratory, and virtual laboratory at the end. Additionally recognized weak and strong sides of used methods are discussed.
Keywords: education, biology, computer-supported laboratory, simulations, secondary schools
Published: 07.06.2012; Views: 1211; Downloads: 46
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Chiral discrimination in mobile phases for HPLCRenato Lukač
, Andrew J. Clark
, Syma Khalid
, Alison Rodger
, Alan Snedden
, P. Mark Rodger
, 2002, original scientific article
Abstract: In this paper we present an algorithm and some preliminary results of a computer simulation study designed to elucidate the molecular interaction mechanisms associated with chiral discrimination in chiral high performance liquid chromatography (HPLC). Molecular dynamics simulations have been performed on a novel active stationary phase constituent based on disaccharides and a model analyte in a typical solvent used as mobile phase in chiral HPLC. The results are interpreted in terms of typical binding geometries and energies found from the simulations. This paper provides basic algorithms for predicting enantiometric selectivity and for investigating the implications for choice of parameters such as solvent polarity and temperature for optimising chiral HPLC separations
Keywords: physical chemistry, liquid crystals, liquid chromatography, computer simulations, spectroscopy
Published: 07.06.2012; Views: 893; Downloads: 33
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Computer Modelling of Porous Composite Structures with Advanced Pore MorphologyAljaž Kovačič
, 2016, doctoral dissertation
Abstract: Advanced pore morphology (APM) structures are composite metal foams, which are assembled from a large number of small spherical elements with cellular structure, and are bonded into a composite with polymeric adhesive. The result of such composition is a wide spectrum of achievable mechanical behaviour in APM structures. To explore their full potential, efficient computational models are needed, which allow for simple parameter variation. Unfortunately, the current computer models do not allow for efficient simulations of porous composite structures with advanced pore morphology, as they employ complex discretisation approaches.
A new approach to simulation is presented in this work, based on the discrete particle method (DPM), where every element of APM structure is discretised with a single node. This enables more efficient simulations of APM structures, while still allowing for simple variation of structural parameters. The DPM method was augmented with constitutive models of normal and tangential contact behaviour of APM elements and bonds between them, which were formulated based on an extensive experimental study of APM structure's geometry and mechanical behaviour. Consequently, the models enable simulations of large APM structure's behaviour by modelling the contact behaviour of individual elements.
The implementation of new models was verified on a set of analytically solvable examples, and the accuracy of the models was validated with very good correspondence between computational and experimental results. Moreover, the models were validated on a wide set of examples, also taking into account the various strain rates and the absence of the bonds.
The applicability of new models was demonstrated in a comprehensive parametrical study, where the influential structural parameters and properties were identified for low and high strain rate deformations. The study also demonstrated the possibility of customising the mechanical behaviour with property gradation, and with introduction of regular, as well as geometrically complex APM element assemblies. The possibility of coupled discrete particle method and finite element method simulations was also addressed.
The newly developed models represent a breakthrough in the field of computational investigation of APM structures, and provide for simpler and more efficient investigations of APM structures in the future.
Keywords: Metal foams, advanced pore morphology, composite materials, mechanical properties, contact modelling, discrete particle methods, computer simulations
Published: 11.03.2016; Views: 1302; Downloads: 107
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Buckling behavior of cold-formed studs with thermal perforationsMarsel Garifullin
, Alexey Sinelnikov
, Maria Bronzova
, Boštjan Kovačič
, Rok Kamnik
, 2016, published scientific conference contribution
Abstract: Studies have shown that the optimal structural scheme for low-rise buildings that meets all regulatory requirements is a frame system. In this connection, thin-walled cold-formed steel (CFS) profiles seem to be the best material for constructing light steel framed (LSF) walls. The framework of LSF walls is usually constructed from CFS C-shaped profiles. To increase the thermal effectiveness of a wall, CFS profiles usually have thermal perforations and thus are called thermoprofiles. However, these openings have a negative impact on bearing capacity of profiles and require accurate evaluation. In this article a relatively new reticular-stretched thermoprofile with diamond-shaped openings is considered. The article deals with the buckling analysis of perforated CFS C-sections subjected to compression.
Keywords: structural engineering, steel structures, computer simulations, nonlinear model
Published: 29.08.2016; Views: 547; Downloads: 254
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Perspectives on the introduction of computer-supported real laboratory exercises into biology teaching in secondary schoolsAndreja Špernjak
, Andrej Šorgo
, 2009, original scientific article
Abstract: Computer supported virtual and real laboratories are recognized as tools that can help in raising the quality of biology instruction, and raising development competences in students. Yet biology teachers have been treating the computer as typewriter, as a source of information and as a tool for communication, all of which usages are common to all subjects. The uses of ICT that can significantly help in developing scientific literacy and that are primary tools in science teaching - such as the use of data loggers - are only rarely on the syllabus. The lack of equipment is not the most important reason for failure to use such applications; instead, this is probably due to teachers' attitudes, opinions and knowledge. Students cannot be recognized as an obstacle in working with ICT. Lawer secondary school students aged between 10 and 14 performed three laboratory exercises (Activity of yeast, Gas exchange in breathing, Heart rate) using three different methods: classic, computer-supported and virtual laboratory. As a result of testing, we know that all three methods are suitable even for younger students. When students were asked which method they liked the most, their first choice was computer-supported laboratory, followed by classic laboratory, with virtual laboratory in the third place.
Keywords: education, biology, secondary education, computer-supported laboratory, laboratory work, ICT, simulations
Published: 15.12.2017; Views: 534; Downloads: 60
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