1. Slovenian Chemistry Teachers' Understanding of Project-based LearningHanija Bujas, 2020, magistrsko delo Opis: Project-based learning (PBL) is a teaching method through which students gain knowledge and skills while working on a project for an extended period of time. They investigate and respond to an authentic, engaging, and complex problem. The popularity of PBL is constantly rising. However, PBL is hard to understand and therefore harder to implement in schools. In the master's thesis we wanted to understand how Slovenian chemistry teachers understand PBL, and how do they implement it in their teaching of chemistry or chemistry related subjects. We created a questionnaire on Google forms and distributed it to chemistry teachers of all Slovenian lower secondary schools and general upper secondary schools. We gathered 130 answers, out of which 95 were teachers who teach in lower secondary schools and 35 who teach in general upper secondary schools. According to the results, teachers barely understand PBL. A majority of teachers are convinced that they use PBL, when the results show that in practice they do not. Project-based learning is often confused for problem-based learning, which is the main confusion for the teachers. Our respondents believe that, because of extensive curriculum and lack of time, it is not possible to fully implement PBL in Slovenian schools.
Ključne besede: project-based learning, teachers, chemistry, understanding
Objavljeno v DKUM: 29.10.2020; Ogledov: 697; Prenosov: 50
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2. Using chemical models for developing natural science competences in teaching chemistry : from pupils as model assemblers to pupils as creators of self-made modelsDarinka Sikošek, Mateja Žuželj, 2013, izvirni znanstveni članek Opis: Chemical models are indispensable tool in chemistry class and enable secondary school pupils to develop complex thought processes and spatial concepts, both of which are necessary to improve their understanding of chemical concepts. In this research, special emphasis is given to complex competencies not only their acquisition, but rather how pupils develop them. For this purpose, a learning strategy has been developed, called learning by self-generating chemical models. Pupils learn individually on their own models, which are made from easily accessible, low-cost materials. The impact of workable models was investigated (assembly of commercial models and production of self-made models) on the (1) learning success using simple molecule shapes and (2) the degree of competence development which realized through the implemented activities. The study involved first-year secondary school-pupils, defined as self-creators of paper- and -wire models (experimental group) and assemblers of commercial models (called the control group). The appearance of the molecules being studied took the form of geometric shapes and structures, which pupils present by making of ball-, called wire-models from plasticine and wire or paper created, called paper models. Based on the results of statistical processing of the data, we found that self-creation of models (as an innovative approach) leads to better understanding and to subsequently sustained knowledge for the pupil. It should also be noted that pupils who were self-generators in comparisons to those who merely assembled the models, generally developed many complex skills in the areas of problem solving, practical competence, mathematical competence and critical thinking skills. The knowledge so acquired was also better understood.
Ključne besede: education, chemical models, competencies, chemistry, self-made models
Objavljeno v DKUM: 19.12.2017; Ogledov: 1114; Prenosov: 65
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3. Implementation of process-targeted activities of prospective chemistry teachers during continuous teaching practice : a rational comparative analysis of teaching methods according to the expressed competenciesDarinka Sikošek, Kornelia Žarić, 2013, izvirni znanstveni članek Opis: The main aim of the teacher study program is to ensure the proper role of teaching practice, which is included in initial teacher training courses. It is necessary that teachers of chemistry gain or develop learner competencies for appropriate teaching/ learning in the chemistry subject by using innovative teaching methods. In terms of activities and methods correction of the continuous teaching practice model for prospective chemistry teachers in Pedagogical study program of 2nd degree "Educational Chemistry" which would ensure the creation of a competent chemistry teacher (active and innovative). The main result of the study is a list of potential competencies by prospective chemistry teachers using innovative teaching methods. These competencies can be developed and produced in the performance of activities defined by using continuous teaching practice, particularly in the areas of testing and assessment, experiential and collaborative learning, and experimental (laboratory and field) work. Each of these components is separately assessed by activity and competence.
Ključne besede: education, innovative teaching methods, competencies, chemistry
Objavljeno v DKUM: 15.12.2017; Ogledov: 783; Prenosov: 93
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4. Development of the research tool to identify factors affecting the use of chemistry educational softwareKateřina Chroustová, Martin Bílek, Andrej Šorgo, 2015, izvirni znanstveni članek Opis: Currently, the implementation of information and communication technologies (ICT) has been strongly recommended to science teachers. For identification the factors of successful ICT implementation the Unified Theory of Use and Acceptance of Technology (UTAUT) is applied, which works as the theoretical background of planned monitoring of Czech chemistry teachers´ attitudes to this problem. This theoretical review introduces the process of creating the modified UTAUT model serving as the basis for a research tool to be exploited for the future survey. Within this process three sources were exploited: (1) theories dealing with factors which influence user behaviour in relation to the use of modern technologies, (2) the analysis of research results focused on the acceptance and use of ICT in chemistry instruction and (3) results of researches conducted by the authors in the field of the effectiveness of the educational software used in chemistry teaching and learning. The conducted analysis of these three sources resulted in defining the presented survey and designing the appropriate theoretical model and research tool.
Ključne besede: education, chemistry education, educational software, teachers' attitudes
Objavljeno v DKUM: 15.12.2017; Ogledov: 836; Prenosov: 128
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5. Synthesis, crystal structure and magnetic properties of a new hydroxylammonium fluoroferrateBrina Dojer, Matjaž Kristl, Zvonko Jagličić, Amalija Golobič, Marta Kasunič, Mihael Drofenik, 2012, izvirni znanstveni članek Opis: This paper reports on the synthesis of a new hydroxylammonium fluoroferrate, with the formula $(NH_3OH)_3FeF_6$, obtained after dissolving iron powder in hydrofluoric acid and adding solid $NH_3OHF$. This new compound has been characterized by chemical and thermal analysis, single-crystal X-ray diffraction, and magnetic measurements. The title compound crystallizes trigonal, R3c, with cell parameters a = 11.4154(2) Å, c = 11.5720(2) Å, Z = 6. The structure consists of $NH_3OH^+$ cations and isolated $FeF_6^{3–}$ octahedra in which the central ion lies on a threefold axis. The oxygen and nitrogen atoms of the hydroxylammonium cations are donors of hydrogen bonds to fluoride anions, resulting in a network of hydrogen bonds between counterions. The effective magnetic moment $µ_{eff}$ = 5.8 BM was calculated and perfectly matches the expected value of high-spin Fe(III) ions. The thermal decomposition of the compound was studied by TG, DSC, and X-ray powder diffraction.
Ključne besede: inorganic chemistry, crystallography, coordination compounds, synthesis, crystal structure, characterization of compounds, determination of the structure of compounds, X-ray diffraction, magnetic measurements, thermal analysis, TG, DSC, hydrogen bond, metal complexes, hydroxylammonium fluoromethalatehydroxylammonium, fluoroferrate
Objavljeno v DKUM: 25.08.2017; Ogledov: 1621; Prenosov: 62
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6. Synthesis and characterisation of hydroxylammonium fluorochromateMatjaž Kristl, Mihael Drofenik, Ljubo Golič, Amalija Golobič, 2003, izvirni znanstveni članek Opis: Reactions in the system $Cr – NH_3OHF – HF – H_2O$ were investigated. Green crystals of a new compound with the formula $(NH_3OH)_3CrF_6$ have been isolated from the water solution and characterized by chemical analysis. The compound crystallizes as triclinic, P-1, with cell parameters: a = 6.5461(2) Å, b = 6.9347(2) Å, c = 9.4072(3) Å, α = 86.772(1)°, β = 83.804(1)°, γ = 70.283(1)°. The effective magnetic moment, $µ_{eff}$ = 3.82 BM, was calculated from magnetic susceptibility measurements in the temperature range 80-290 K. The thermal decomposition of the compound was studied by TG and DSC analysis. $(NH_3OH)_3CrF_6$ decomposes above 125 °C in three steps and the residue has been identified by X-ray powder diffraction as $α – Cr_2O_3$.
Ključne besede: inorganic chemistry, structural chemistry, crystalline structure, coordination compounds, synthesis, inorganic reactions, thermal decomposition, characterization of compounds, TG, DSC, X-ray diffraction, chromium complexes, hydroxylammonium fluoro chromates, crystals
Objavljeno v DKUM: 25.08.2017; Ogledov: 1387; Prenosov: 108
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7. Effect of peptides' binding on the antimicrobial activity and biocompatibility of protein-based substrates Maja Kaisersberger Vincek, 2017, doktorska disertacija Opis: This work reveals the effect of coupling approach (chemical by using carbodiimide chemistry and grafting-to vs. grafting-from synthesis routes, and enzymatic by using transglutaminase) of a hydrophilic ε-poly-L-lysine (εPL) and an amphiphilic oligo-acyl-lysyl (OAK) derivative (K-7α12-OH) to wool fibers and gelatine (GEL) macromolecules, respectively, and substrates antibacterial activity against Gram-negative E. coli and Gram-positive S. aureus bacteria after 1–24 h of exposure, as well as their cytotoxicity. Different spectroscopic (ultraviolet-visible, infrared, fluorescence and electron paramagnetic resonance) and separation techniques (size-exclusion chromatography and capillary zone electrophoresis) as well as zeta potential and potentiometric titration analysis, were performed to confirm the covalent coupling of εPL/OAK, and to determine the amount and orientation of its immobilisation.
The highest and kinetically the fastest level of bacterial reduction was achieved with wool/GEL functionalised with εPL/OAK by chemical grafting-to approach. This effect correlated with both the highest grafting yield and conformationally the highly-flexible (brush-like) orientation linkage of εPL/OAK, implicating on the highest amount of accessible amino groups interacting with bacterial membrane. However, OAK`s amphipathic structure, the cationic charge and the hydrophobic moieties, resulted to relatively high reduction of S. aureus for grafting-from and the enzymatic coupling approaches using OAK-functionalised GEL.
The εPL/OAK-functionalised GEL did not induce toxicity in human osteoblast cells, even at ~25-fold higher concentration than bacterial minimum inhibitory (MIC) concentration of εPL/OAK, supporting their potential usage in biomedical applications.
It was also shown that non-ionic surfactant adsorbs strongly onto the wool surface during the process of washing, thereby blocking the functional sites of immobilized εPL and decreases its antibacterial efficiency.
Ključne besede: wool, gelatine, antimicrobial peptides, ε-poly-L-lysine, oligo-acyl-lysyl, grafting chemistry, grafting approach, peptide orientation, antibacterial activity, cytotoxicity
Objavljeno v DKUM: 17.08.2017; Ogledov: 1427; Prenosov: 152
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8. A silver/silver sulphide selective electrode prepared by means of chemical treatments of silver wireDanilo Dobčnik, Igor Gros, Mitja Kolar, 1998, izvirni znanstveni članek Opis: The preparation and usability of a sulphide ion selective electrode, prepared by means of chemical pretreatment of silver wire with an ammonium perdisulphate solution, and the sulphidization in an alkaline sulphide solution are described. The electrode is suitable for direct potentiometric measuring of sulphide in alkaline solutions of concentrations down to ▫$1 X 10^{-6} mol/L$▫. The 45 min required for each chemical treatment are enough for the preparation of the described electrode.
Ključne besede: analytical chemistry, ion selective electrode, preparation, silver wire, potentiometric measurements, sulphide ions
Objavljeno v DKUM: 17.08.2017; Ogledov: 993; Prenosov: 110
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9. A novel approach to N,N'-dimethyl and N,N'-ethylene bridged dibenzodithiadiazafulvalaneZdenko Časar, Dominique Lorcy, Ivan Leban, Alenka Majcen Le Marechal, 2002, izvirni znanstveni članek Opis: A novel approach to electron rich olefins, such as dibenzodithiadiazafulvalenes (DTDAFs) is reported. These compounds have been prepared by alkalination of the benzothiazole-2-thione ring. The first crystal structure of the N,N'-dimethyl dibenzoDTDAF dicationis also reported.
Ključne besede: organic chemistry, benzothiazole, thermal rearrangement, dithiadiazafulvalene, dication
Objavljeno v DKUM: 17.08.2017; Ogledov: 786; Prenosov: 129
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10. Synthesis of nickel and cobalt sulfide nanoparticles using a low cost sonochemical methodMatjaž Kristl, Brina Dojer, Sašo Gyergyek, Janja Kristl, 2017, izvirni znanstveni članek Opis: Nickel and cobalt sulfides are promising materials in different cutting-edge research areas like solar cells, supercapacitors, catalysts, and electrode materials. Nickel and cobalt sulfides with various stoichiometries have been synthesized sonochemically from $Ni(CH_3COO)_2$ ∙ $4H_2O$, $Co(CH_3COO)_2$ ∙ $2H_2O$ and different sulfur precursors using a direct immersion ultrasonic probe. The products were characterized by X-ray powder diffraction, transmission electron microscopy (TEM) including EDX analysis, IR and UV–Vis spectroscopy and elemental analysis. Following products have been obtained: $NiS$, $Ni_3S_4$, $CoS_{1.097}$ and $Co_9S_8$, with average crystallite sizes in the range 7−30 nm. Effects of different reaction conditions on the size, morphology and optical band-gap energy were evaluated. Optical band-gap energies in the range 3.3 eV−3.8 eV were observed for the obtained nanoparticles.
Ključne besede: material science, inorganic chemistry, nanotechnology
Objavljeno v DKUM: 14.07.2017; Ogledov: 1267; Prenosov: 376
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