25 research outputs found
Joining with industry: innovative curriculum materials for technology and science for primary schools
There is a perceived need for curriculum materials that would support primary teachers taking up work placements. Primary classroom materials of this kind should encourage children to be innovative, develop analytical and problem solving skills and be pro-active towards their own learning. The rationale for the development of such a pack of curriculum materials for primary technology and science is discussed in relation to the educational and curriculum contexts of the materials and the ways in which innovative qualities can be developed in children through the use of 'real' contexts for classroom based work. The way in which product analysis can be used to facilitate understanding of innovation in the world of work is examined and some exemplar activities are provided
Computerâassisted assessment: suggested guidelines for an institutional strategy
Online Learning examines the influence of new technologies on online pedagogy and provides an authoritative synthesis of existing research in the field. It also investigates the direction of e-Learning in the digital age
Anion Distribution, Structural Distortion, and Symmetry-Driven Optical Band Gap Bowing in Mixed Halide Cs2SnX6 Vacancy Ordered Double Perovskites.
Mixed anion compounds in the Fm3Ì
m vacancy ordered perovskite structure were synthesized and characterized experimentally and computationally with a focus on compounds where A = Cs+. Pure anion Cs2SnX6 compounds were formed with X = Cl, Br, and I using a room temperature solution phase method. Mixed anion compounds were formed as solid solutions of Cs2SnCl6 and Cs2SnBr6 and a second series from Cs2SnBr6 and Cs2SnI6. Single phase structures formed across the entirety of both composition series with no evidence of long-range anion ordering observed by diffraction. A distortion of the cubic A2BX6 structure was identified in which the spacing of the BX6 octahedra changes to accommodate the A site cation without reduction of overall symmetry. Optical band gap values varied with anion composition between 4.89 eV in Cs2SnCl6 to 1.35 eV in Cs2SnI6 but proved highly nonlinear with changes in composition. In mixed halide compounds, it was found that lower energy optical transitions appeared that were not present in the pure halide compounds, and this was attributed to lowering of the local symmetry within the tin halide octahedra. The electronic structure was characterized by photoemission spectroscopy, and Raman spectroscopy revealed vibrational modes in the mixed halide compounds that could be assigned to particular mixed halide octahedra. This analysis was used to determine the distribution of octahedra types in mixed anion compounds, which was found to be consistent with a near-random distribution of halide anions throughout the structure, although some deviations from random halide distribution were noted in mixed iodide-bromide compounds, where the larger iodide anions preferentially adopted trans configurations
Stigma of Seeking Psychological Services: Examining College Students Across Ten Countries/Regions
© Division of Counseling Psychology of the American Psychological Association. Stigma is an important barrier to seeking psychological services worldwide. Two types of stigma exist: public stigma and self-stigma. Scholars have argued that public stigma leads to self-stigma, and then self-stigma is the primary predictor of attitudes toward seeking psychological services. However, this assertion is largely limited to U.S. samples. The goal of this research was to provide a first step in understanding the relationship between public stigma, self-stigma, and attitudes toward seeking psychological services in international contexts (N = 3,276; Australia, Brazil, Canada, Hong Kong, Portugal, Romania, Taiwan, Turkey, United Arab Emirates, and United States). Using structural equation modeling, we found that self-stigma mediated the relationship between public stigma and attitudes toward seeking services among college students in each country and region. However, differences in path strengths emphasize the need to pay attention to the role of public and self-stigma on attitudes toward seeking psychological services throughout the world
Einfluss der Verarbeitungstechnologie und Werkstoffzusammensetzung auf die Struktur-Eigenschafts-Beziehungen von thermoplastischen Nanoverbundwerkstoffen
Die Einarbeitung von nanoskaligen FĂŒllstoffen zur Steigerung von polymeren Eigenschaftsprofilen
ist sehr viel versprechend und stöĂt daher heutzutage sowohl in der
Forschung als auch in der Industrie auf groĂes Interesse. Bedingt durch ausgeprĂ€gte
OberflÀchen und hohe AnziehungskrÀfte, liegen Nanopartikel allerdings nicht singulÀr
sondern als PartikelanhÀufungen, so genannten Agglomeraten oder Aggregaten, vor.
Zur Erzielung der gewĂŒnschten Materialverbesserungen gilt es, diese aufzuspalten
und homogen in der polymeren Matrix zu verteilen.
Bei thermoplastischen Kunststoffen ist die gleichlÀufige Doppelschneckenextrusion
eines der gĂ€ngigsten Verfahren zur Einarbeitung von Additiven und FĂŒllstoffen. Aus
diesem Grund war es Ziel dieser Arbeit, mittels dieses Verfahrens verbesserte Verbundwerkstoffe
mit Polyamid 66- und Polyetheretherketon-Matrix, durch Einarbeitung
von nanoskaligem Titandioxid (15 und 300 nm), zu generieren.
In einem ersten Schritt wurden die verfahrenstechnischen Parameter, wie Drehzahl
und Durchsatz, sowie die ProzessfĂŒhrung und damit deren Einfluss auf die Materialeigenschaften
beleuchtet.
Der spezifische Energieeintrag ist ausschlaggebend zur Deagglomeration der Nanopartikel.
Dieser zeigte leichte AbhÀngigkeiten von der Drehzahl und dem Durchsatz
und verursachte bei der Einarbeitung der Partikel keine wesentlichen Unterschiede in
der Aufspaltung der Partikel sowie gar keine in den resultierenden mechanischen
Eigenschaften. Die ProzessfĂŒhrung wurde unterteilt in Mehrfach- und Einfachextrusion.
Die Herstellung eines hochgefĂŒllten Masterbatches, dessen mehrfaches
Extrudieren und anschlieĂendes VerdĂŒnnen, fĂŒhrte zu einer sehr guten Deagglomeration
und stark verbesserten Materialeigenschaften. Mittels Simulation des
Extrusionsprozesses konnte festgestellt werden, dass das Vorhandensein von ungeschmolzenem
Granulat in der Verfahrenszone zu einer Schmelze/Nanopartikel/
Feststoffreibung fĂŒhrt, die die Ursache fĂŒr eine sehr gute Aufspaltung der Partikel zu
sein scheint. Durch Modifikation des Extrusionsprozesses erreichte die Einfachextrusion
annÀhernd den Grad an Deagglomeration bei Mehrfachextrusion, wobei die
Materialien bei letzterem Verfahren die besten Eigenschaftsprofile aufwiesen.
In einem zweiten Schritt wurde ein Vergleich der EinflĂŒsse von unterschiedlichen
PartikelgröĂen und âgehalten auf die polymeren Matrizes vollzogen. Die 15 nm Partikel zeigten signifikant bessere mechanische Ergebnisse auf als die 300 nm Partikel,
und die Wirkungsweise des 15 nm Partikels auf Polyetheretherketon war stÀrker als
auf Polyamid 66. Es konnten Steigerungen in Steifigkeit, Festigkeit und ZĂ€higkeit
erzielt werden. Rasterelektronenmikroskopische Aufnahmen bestÀtigten diese Ergebnisse.
Eine Berechnung der Plan-Selbstkosten von einem Kilogramm PEEK-Nanoverbundwerkstoff
im Vergleich zu einem Kilogramm unverstÀrktem PEEK verdeutlichte, dass
ein Material kreiert wurde, welches deutlich verbesserte Eigenschaften bei gleichem
Preis aufweist.
Zusammenfassend konnte in dieser Arbeit ein tieferes VerstÀndnis des Extrusionsvorganges
zur Herstellung von kostengĂŒnstigen und verbesserten Thermoplasten
durch das Einbringen von Nanopartikeln gewonnen werden
Problems with using a supervisor's report as a form of summative assessment
The place of a supervisor report when used as a summative assessment of clinical workplace based learning is discusse
Anion Distribution, Structural Distortion, and Symmetry-Driven Optical Band Gap Bowing of Mixed Halide Cs2SnX6 Vacancy Ordered Double Perovskites
Mixed anion compounds in the Fm-3m vacancy ordered perovskite structure were synthesised and characterised experimentally and computationally with a focus on compounds where A = Cs+. Pure anion Cs2SnX6 compounds were formed with X = Cl, Br and I using a room temperature solution phase method. Mixed anion compounds were formed as solid solutions of Cs2SnCl6 and Cs2SnBr6 and a second series from Cs2SnBr6 and Cs2SnI6. Single phase structures formed across the entirety of both composition series, with no evidence of long range anion ordering observed by diffraction. A distortion of the cubic A2BX6 structure was identified in which the spacing of the BX6 octahedra changes to accommodate the A site cation without reduction of overall symmetry. Optical band gap values varied with anion composition between 4.89 eV in Cs2SnCl6 to 1.35 eV in Cs2SnI6, but proved highly non-linear with changes in composition. In mixed halide compounds it was found that lower energy optical transitions appeared that were not present in the pure halide compounds, and this could be attributed to lowering of the local symmetry within the tin halide octahedra. The electronic structure was characterised by photoemission spectroscopy, and Raman spectroscopy revealed vibrational modes in the mixed halide compounds that could be assigned to particular mixed halide octahedra. This analysis was used to determine the distribution of octahedra types in mixed anion compounds, which was found to be consistent with a near-random distribution of halide anions throughout the structure, although some deviations from random halide distribution were noted in mixed iodide-bromide compounds, where the larger iodide anions preferentially adopted trans configurations
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(Published By M. Witmark
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Anion Distribution, Structural Distortion, and Symmetry-Driven Optical Band Gap Bowing in Mixed Halide Cs2SnX6 Vacancy Ordered Double Perovskites.
Mixed anion compounds in the Fm3Ì
m vacancy ordered perovskite structure were synthesized and characterized experimentally and computationally with a focus on compounds where A = Cs+. Pure anion Cs2SnX6 compounds were formed with X = Cl, Br, and I using a room temperature solution phase method. Mixed anion compounds were formed as solid solutions of Cs2SnCl6 and Cs2SnBr6 and a second series from Cs2SnBr6 and Cs2SnI6. Single phase structures formed across the entirety of both composition series with no evidence of long-range anion ordering observed by diffraction. A distortion of the cubic A2BX6 structure was identified in which the spacing of the BX6 octahedra changes to accommodate the A site cation without reduction of overall symmetry. Optical band gap values varied with anion composition between 4.89 eV in Cs2SnCl6 to 1.35 eV in Cs2SnI6 but proved highly nonlinear with changes in composition. In mixed halide compounds, it was found that lower energy optical transitions appeared that were not present in the pure halide compounds, and this was attributed to lowering of the local symmetry within the tin halide octahedra. The electronic structure was characterized by photoemission spectroscopy, and Raman spectroscopy revealed vibrational modes in the mixed halide compounds that could be assigned to particular mixed halide octahedra. This analysis was used to determine the distribution of octahedra types in mixed anion compounds, which was found to be consistent with a near-random distribution of halide anions throughout the structure, although some deviations from random halide distribution were noted in mixed iodide-bromide compounds, where the larger iodide anions preferentially adopted trans configurations