Browsing by Subject "Tool"
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Item Open Access Assessing prospective chemistry teachers' understanding of gases through qualitative and quantitative analyses of their concept maps(R S C Publications, 2013-04) Kibar, Z. B.; Yaman, F.; Ayas, A.The use of concept mapping as a tool to measure the meaningful learning of students is the focus of this study. The study was carried out with 24 last year students (22 years old) from the Department of Chemistry Teaching at Fatih Faculty of Education, Karadeniz Technical University (KTU). Prospective Chemistry Teachers (PCT) were asked to create concept maps using a list of given concepts related to gases. An examination of the PCTs' maps revealed that the students could not form hierarchical maps even after being shown examples of the basic elements and meaningful propositions between the concepts. After being provided with feedback about their concept maps and trained to form non-hierarchical concept maps, the students were asked to create new maps. This time they were allowed to use either hierarchical or non-hierarchical maps. When their new maps were examined, we found that most of the PCTs formed non-hierarchical maps. However, they still could not form meaningful relationships between the given concepts. We also found that the PCTs had some misconceptions about gases and kinetic molecular theory that explains gas behavior. The study ended up with some suggestions and implications for educators and researchers related to pre-service teachers' training.Item Open Access Convolution, filtering, and multiplexing in fractional Fourier domains and their relation to chirp and wavelet transforms(1994) Özaktaş, Haldun M.; Barshan, B.; Mendlovic, D.; Onural, L.A concise introduction to the concept of fractional Fourier transforms is followed by a discussion of their relation to chirp and wavelet transforms. The notion of fractional Fourier domains is developed in conjunction with the Wigner distribution of a signal. Convolution, filtering, and multiplexing of signals in fractional domains are discussed, revealing that under certain conditions one can improve on the special cases of these operations in the conventional space and frequency domains. Because of the ease of performing the fractional Fourier transform optically, these operations are relevant for optical information processing.Item Open Access Hard turning with variable micro-geometry PcBN tools(Elsevier, 2008) Özel, T.; Karpat, Y.; Srivastava, A.This paper presents investigations on hard turning with variable edge design PcBN inserts. Turning of hardened AISI 4340 steel with uniform and variable edge design PcBN inserts is conducted, forces and tool wear are measured. 3D finite element modelling is utilized to predict chip formation, forces, temperatures and tool wear on uniform and variable edge micro-geometry tools. Predicted forces and tool wear contours are compared with experiments. The temperature distributions and tool wear contours demonstrate the advantages of variable edge micro-geometry design.Item Open Access A signal transduction score flow algorithm for cyclic cellular pathway analysis, which combines transcriptome and ChIP-seq data(Royal Society of Chemistry, 2012) Isik, Z.; Ersahin, T.; Atalay, V.; Aykanat, Cevdet; Cetin Atalay, R.Determination of cell signalling behaviour is crucial for understanding the physiological response to a specific stimulus or drug treatment. Current approaches for large-scale data analysis do not effectively incorporate critical topological information provided by the signalling network. We herein describe a novel model- and data-driven hybrid approach, or signal transduction score flow algorithm, which allows quantitative visualization of cyclic cell signalling pathways that lead to ultimate cell responses such as survival, migration or death. This score flow algorithm translates signalling pathways as a directed graph and maps experimental data, including negative and positive feedbacks, onto gene nodes as scores, which then computationally traverse the signalling pathway until a pre-defined biological target response is attained. Initially, experimental data-driven enrichment scores of the genes were computed in a pathway, then a heuristic approach was applied using the gene score partition as a solution for protein node stoichiometry during dynamic scoring of the pathway of interest. Incorporation of a score partition during the signal flow and cyclic feedback loops in the signalling pathway significantly improves the usefulness of this model, as compared to other approaches. Evaluation of the score flow algorithm using both transcriptome and ChIP-seq data-generated signalling pathways showed good correlation with expected cellular behaviour on both KEGG and manually generated pathways. Implementation of the algorithm as a Cytoscape plug-in allows interactive visualization and analysis of KEGG pathways as well as user-generated and curated Cytoscape pathways. Moreover, the algorithm accurately predicts gene-level and global impacts of single or multiple in silico gene knockouts. This journal is © The Royal Society of Chemistry 2012.