Scientific literacy and its development by using learning tasks in Chemistry for ISCED 2 level

Cílem disertační práce bylo posouzení vhodnosti rozvoje přírodovědné gramotnosti s využitím učebních úloh v hodinách chemie pro oblast ISCED 2. V České republice jsou pravidelně zjišťovány funkční gramotnosti v rámci mezinárodních šetření pořádaných OECD. Srovnáním typů úloh v komerčních pracovních sešitech a úloh používaných v PISA testování byl zjištěn výrazný rozdíl ve způsobu jejich zadání (problémovost) a kognitivních cílů, které autoři plánují dosáhnout. Z autorských a uvolněných úloh PISA byly sestaveny sbírky, které učitelé v průběhu školního roku 2016/2017 používali ve své výuce. Na základě výsledků žáků v realizovaném pedagogickém kvaziexperimentu lze říci, že žáci experimentální skupiny dosáhli lepších výsledků než žáci v kontrolní skupině při řešení komplexních úloh. Naopak výsledky žáků na základních školách byly u výstupních testových úloh výrazně horší než u vstupních, což bylo vysvětleno ztrátou motivace ke studiu. Motivace žáků při řešení komplexních úloh byla nadprůměrná. Uvědomovali si význam a užitečnost komplexních úloh, a proto jejich řešení přikládali náležitou důležitost. Učitelé se shodli, že komplexní úlohy jsou zajímavým učebním materiálem pro zařazení do výuky. Ocenili, že řešená témata jsou žákům předložena problémovou formou, v širším kontextu a s důrazem na propojení...The objective of the dissertation was to assess the suitability of the scientific literacy development by using learning tasks in chemistry classes for ISCED 2. By comparing the learning tasks types in commercial workbooks and in the international assessment PISA, a significant difference in their structure was found out. Although the Czech Republic has undertaken to participate in the PISA project, Czech teachers have a different type of teaching tasks commonly available in their workbooks than the pupils afterwards solve in the PISA project. PISA's released and author's learning tasks were compiled into authentic workbooks. They were used in chemistry classes during the school year 2016/2017. Based on the pupils' results in the final assignments, all groups of grammar school pupils from experimental groups achieved better results in solving multicomponent learning tasks than the control group. However, the results of elementary schools pupils were significantly worse at final test scores than at initial ones, which was explained by the entire loss of their motivation to study. Pupils rated motivation to work with multicomponent tasks above average. They were fully aware of the importance and usefulness of solving multicomponent learning tasks, and, therefore, they solved them with proper...Katedra učitelství a didaktiky chemieDepartment of teaching and Didactics of ChemistryPřírodovědecká fakultaFaculty of Scienc

Influence of diluent alkyl substitution on the extraction of Am(III) and Eu(III) by a 6,6’-bis(1,2,4-triazin-3-yl)-2,2’-bipyridine ligand dissolved in alkylated cyclohexanone Diluents

Several alkylated cyclohexanones were investigated as potential diluents for the selective extraction of Am(III) from Eu(III) from nitric acid solutions by the CyMe4-BTBP ligand. No significant extraction of either of the metal ions was observed for these diluents themselves. In the extractions from 1 M HNO3, 3-methylcyclohexanone and 4-methylcyclohexanone gave comparable results to cyclohexanone whereas in the extractions from 4 M HNO3, 2-methylcyclohexanone, 3-methylcyclohexanone and 4-methylcyclohexanone all gave superior results. For the monomethylated diluents, DAm and SFAm/Eu decreased in the order of alkyl substitution 2 > 4 ~ 3. However, alkyl substitution of cyclohexanone significantly slows down the extraction kinetics compared to cyclohexanone, and the position of alkyl substitution was found to play an important role in the solvents properties. 3-Methylcyclohexanone was identified as the most promising of the diluent

Nuclear Chemistry and Chemistry of f-Elements in Chemistry Curriculum at Secondary Schools

V úvodu diplomové práce nazvané Výuka jaderné chemie a chemie f-prvků na středních školách je uvedena rešerše nejpoužívanějších středoškolských učebnic, v rámci které se posuzovala témata stavba atomu, radioaktivita a f-prvky. Cílem rešerše bylo zjistit, zda současné učebnice odpovídají požadavkům uvedených v kurikulárních dokumentech. Na základě rešerše byly vytvořeny učební texty, materiály a učební úlohy s tématy, která nejsou v současných učebnicích plně pokryty a odráží aktuální stav vědy a techniky. Vybrané úlohy byly hodnoceny středoškolskými učiteli prostřednictvím dotazníkového šetření (prostřednictvím internetu), kde se učitelé vyjádřili i k výuce témat radioaktivita a f-prvky na středních školách. Tytéž učební úlohy byly zadány k vyřešení studentům gymnázia. Výsledky z internetového šetření i výsledky od studentů byly využity k úpravě úloh do konečné podoby.This master's degree thesis, called Nuclear Chemistry and Chemistry of f-Elements in Chemistry Curriculum at Secondary Schools, conducts a research of the most commonly used high school textbooks. Within the textbook research, topics such as atomic nucleus composition, radioactivity, and f-elements were studied in order to evaluate to what extent contemporary textbooks meet to the curriculum requirements. Based on the textbook research, the new teaching texts, materials, and teaching tasks including the uncovered themes were created. Selected teaching tasks were evaluated by high school teachers. Within this pool, the teachers also answered questions concerning teaching topics of radioactivity and chemistry of f-elements at high schools. The same tasks were solved and evaluated by high school students as well. The results of both teacher and student surveys were used for the final modification of the tasks.Department of teaching and Didactics of ChemistryKatedra učitelství a didaktiky chemiePřírodovědecká fakultaFaculty of Scienc

Extraction of minor actinides, lanthanides and other fission products by silica-immobilized BTBP/BTPhen ligands

Novel BTBP [bis-(1,2,4-triazin-3-yl)-2,2’-bipyridine] / BTPhen [bis-(1,2,4-triazin-3-yl)-1,10-phenanthroline] functionalized silica gels have been developed to extract minor actinides, lanthanides and other fission products. BTPhen functionalized silica gel is capable of near-quantitative removal of Am(III) in the presence of Eu(III) from aqueous HNO3, while BTBP functionalized silica gel is able to remove problematic corrosion and fission products that are found in PUREX raffinates

Some Exact Solutions of String Theory in Four and Five Dimensions

We find several classes of exact classical solutions of critical bosonic string theory, constructed as twisted products of one Euclidean and one Minkowskian 2D black hole coset. One class of these solutions leads (after tensoring with free scalars and supersymmetrizing) to a rotating version of the recently discovered exact black fivebrane. Another class represents a one-parameter family of axisymmetric stationary four-dimensional targets with horizons. Global properties and target duality of the 4D solutions are briefly analyzed.Comment: 14 page

Modelling of the Am(III) - Cm(III) kinetic separation effect observed during metal ion extraction by bis-(1,2,4)-triazine ligands

The kinetic separation effect was observed leading to a separation factor for Am(III) over Cm(III) as high as 7.9 by using 2,9-bis-(1,2,4-triazin-3-yl)-1,10-phenantroline (BTPhen) ligands in our recent study. In an attempt to explain the observed tendencies, several kinetic models were tested. A model based on mass transfer as the rate-controlling process was found to best describe the kinetic data and allowed to simulate the dependence of Am/Cm separation factor on time. The calculated values of the overall mass-transfer coefficients confirmed that the observed kinetic effect was caused by the different rates of Am(III) and Cm(III) extraction. This kinetic separation phenomenon and its explanation paves the way for potential new approaches to separation of metal ions with very similar properties, such as the adjacent minor actinides Am(III) and Cm(III)

Synthesis of novel BTPhen-functionalized silica-coated magnetic nanoparticles for separating trivalent actinides and lanthanides

BTPhen [bis-(1,2,4-triazin-3-yl)-1,10-phenanthroline] functionalized magnetic nanoparticles (MNPs), which selectively extracts Am(III) over Eu(III) from 0.1 M HNO3 with fast kinetics and a separation factor of 30 have been synthesized. These MNPs also show a small but significant selectivity for Am(III) over Cm(III) with a separation factor of around 3 in 0.1 M HNO3. We report also the synthesis of these BTPhen and related ligands via an improved synthetic route by-passing the problematic benzylic oxidation with stoichiometric SeO2

Two Dimensional String Theory and the Topological Torus

We analyze topological string theory on a two dimensional torus, focusing on symmetries in the matter sector. Even before coupling to gravity, the topological torus has an infinite number of point-like physical observables, which give rise via the BRST descent equations to an infinite symmetry algebra of the model. The point-like observables of ghost number zero form a topological ground ring, whose generators span a spacetime manifold; the symmetry algebra represents all (ground ring valued) diffeomorphisms of the spacetime. At nonzero ghost numbers, the topological ground ring is extended to a superring, the spacetime manifold becomes a supermanifold, and the symmetry algebra preserves a symplectic form on it. In a decompactified limit of cylindrical target topology, we find a nilpotent charge which behaves like a spacetime topological BRST operator. After coupling to topological gravity, this model might represent a topological phase of $c=1$ string theory. We also point out some analogies to two dimensional superstrings with the chiral GSO projection, and to string theory with $c=-2$.Comment: 22 pages, no figure

Separation of minor actinides from lanthanides using immobilized ligand systems: the role of the counterion

A CyMe4-BTPhen functionalized silica gel that selectively extracts Am(III) over Eu(III) from 4 M HNO3 with a separation factor > 154 has been developed. Evidence is presented that the counterion surrounding the M(III) in the proposed 1:1 [BTPhen:M(III)] complex plays an important role in the complexation of Am(III) and Eu(III)

A MOOC in Nuclear- and Radio-Chemistry: from the design to the feedback

Recently, the loss of expertise in the nuclear- and radio-chemistry (NRC) is becoming an issue of concern, because of few engaging curricula and career prospects. To counteract this trend, the Massive Open Online Course “Essential Radiochemistry for Society” has been developed with the intent of letting young students in scientific matters discover all the benefits of NRC to society and improving their awareness of these disciplines. The MOOC development process as well as the feedbacks collected in the first MOOC editions are analyzed by highlighting strong points and weakness of the followed strategy