@article{KranjcHorvatWienerSchmelingetal.2022, author = {Kranjc Horvat, Anja and Wiener, Jeff and Schmeling, Sascha and Borowski, Andreas}, title = {Learning goals of professional development programs at science research institutions}, series = {Journal of science teacher education : the official journal of the Association for the Education of Teachers in Science}, volume = {33}, journal = {Journal of science teacher education : the official journal of the Association for the Education of Teachers in Science}, number = {1}, publisher = {Routledge, Taylor \& Francis Group}, address = {Abingdon}, issn = {1046-560X}, doi = {10.1080/1046560X.2021.1905330}, pages = {32 -- 54}, year = {2022}, abstract = {Effective professional development programs (PDPs) rely on well-defined goals. However, recent studies on PDPs have not explored the goals from a multi-stakeholder perspective. This study identifies the most important learning goals of PDPs at science research institutions as perceived by four groups of stakeholders, namely teachers, education researchers, government representatives, and research scientists. Altogether, over 100 stakeholders from 42 countries involved in PDPs at science research institutions in Europe and North America participated in a three-round Delphi study. In the first round, the stakeholders provided their opinions on what they thought the learning goals of PDPs should be through an open-ended questionnaire. In the second and third rounds, the stakeholders assessed the importance of the learning goals that emerged from the first round by rating and ranking them, respectively. The outcome of the study is a hierarchical list of the ten most important learning goals of PDPs at particle physics laboratories. The stakeholders identified enhancing teachers' knowledge of scientific concepts and models and enhancing their knowledge of the curricula as the most important learning goals. Furthermore, the results show strong agreement between all the stakeholder groups regarding the defined learning goals. Indeed, all groups ranked the learning goals by their perceived importance almost identically. These outcomes could help policymakers establish more specific policies for PDPs. Additionally, they provide PDP practitioners at science research institutions with a solid base for future research and planning endeavors.}, language = {en} } @article{BuljakBruno2018, author = {Buljak, Vladimir and Bruno, Giovanni}, title = {Numerical modeling of thermally induced microcracking in porous ceramics}, series = {Journal of the European Ceramic Society}, volume = {38}, journal = {Journal of the European Ceramic Society}, number = {11}, publisher = {Elsevier}, address = {Oxford}, issn = {0955-2219}, doi = {10.1016/j.jeurceramsoc.2018.03.041}, pages = {4099 -- 4108}, year = {2018}, abstract = {A numerical framework is developed to study the hysteresis of elastic properties of porous ceramics as a function of temperature. The developed numerical model is capable of employing experimentally measured crystallographic orientation distribution and coefficient of thermal expansion values. For realistic modeling of the microstructure, Voronoi polygons are used to generate polycrystalline grains. Some grains are considered as voids, to simulate the material porosity. To model intercrystalline cracking, cohesive elements are inserted along grain boundaries. Crack healing (recovery of the initial properties) upon closure is taken into account with special cohesive elements implemented in the commercial code ABAQUS. The numerical model can be used to estimate fracture properties governing the cohesive behavior through inverse analysis procedure. The model is applied to a porous cordierite ceramic. The obtained fracture properties are further used to successfully simulate general non-linear macroscopic stress-strain curves of cordierite, thereby validating the model.}, language = {en} } @article{IlinPoppenhaegerAlvaradoGomez2022, author = {Ilin, Ekaterina and Poppenh{\"a}ger, Katja and Alvarado-G{\´o}mez, Juli{\´a}n David}, title = {Localizing flares to understand stellar magnetic fields and space weather in exo-systems}, series = {Astronomische Nachrichten = Astronomical notes}, volume = {343}, journal = {Astronomische Nachrichten = Astronomical notes}, number = {4}, publisher = {Berlin}, address = {Wiley-VCH}, issn = {1521-3994}, doi = {10.1002/asna.20210111}, pages = {7}, year = {2022}, abstract = {Stars are uniform spheres, but only to first order. The way in which stellar rotation and magnetism break this symmetry places important observational constraints on stellar magnetic fields, and factors in the assessment of the impact of stellar activity on exoplanet atmospheres. The spatial distribution of flares on the solar surface is well known to be nonuniform, but elusive on other stars. We briefly review the techniques available to recover the loci of stellar flares, and highlight a new method that enables systematic flare localization directly from optical light curves. We provide an estimate of the number of flares we may be able to localize with the Transiting Exoplanet Survey Satellite, and show that it is consistent with the results obtained from the first full sky scan of the mission. We suggest that nonuniform flare latitude distributions need to be taken into account in accurate assessments of exoplanet habitability.}, language = {en} } @article{ThayumanasundaramRamanVenkatesanOussetetal.2022, author = {Thayumanasundaram, Savitha and Raman Venkatesan, Thulasinath and Ousset, Aymeric and Van Hollebeke, Kim and Aerts, Luc and Wubbenhorst, Michael and Van den Mooter, Guy}, title = {Complementarity of mDSC, DMA, and DRS Techniques in the Study of T-g and Sub-T-g Transitions in Amorphous Solids}, series = {Molecular pharmaceutics}, journal = {Molecular pharmaceutics}, publisher = {American Chemical Society}, address = {Washington}, issn = {1543-8384}, doi = {10.1021/acs.molpharmaceut.2c00123}, pages = {17}, year = {2022}, abstract = {Recently, glasses, a subset of amorphous solids, have gained attention in various fields, such as polymer chemistry, optical fibers, and pharmaceuticals. One of their characteristic features, the glass transition temperature (T-g) which is absent in 100\% crystalline materials, influences several material properties, such as free volume, enthalpy, viscosity, thermodynamic transitions, molecular motions, physical stability, mechanical properties, etc. In addition to T-g, there may be several other temperaturedependent transitions known as sub-T-g transitions (or beta-, gamma-, and delta-relaxations) which are identified by specific analytical techniques. The study of T-g and sub-T-g transitions occurring in amorphous solids has gained much attention because of its importance in understanding molecular kinetics, and it requires the combination of conventional and novel characterization techniques. In the present study, three different analytical techniques [modulated differential scanning calorimetry (mDSC), dynamic mechanical analysis (DMA), and dielectric relaxation spectroscopy (DRS)] were used to perform comprehensive qualitative/quantitative characterization of molecular relaxations, miscibility, and molecular interactions present in an amorphous polymer (PVPVA), a model drug (indomethacin, IND), and IND/PVPVA-based amorphous solid dispersions (ASDs). This is the first ever reported DMA study on PVPVA in its powder form, which avoids the contribution of solvent to the mechanical properties when a selfstanding polymer film is used. A good correlation between the techniques in determining the T-g value of PVPVA, IND, and IND/ PVPVA-based ASDs is established, and the negligible difference (within 10 degrees C) is attributed to the different material properties assessed in each technique. However, the overall T-g behavior, the decrease in T-g with increase in drug loading in ASDs, is universally observed in all the above-mentioned techniques, which reveals their complementarity. DMA and DRS techniques are used to study the different sub-T-g transitions present in PVPVA, amorphous IND, and IND/PVPVA-based ASDs because these transitions are normally too weak or too broad for mDSC to detect. For IND/PVPVA-based ASDs, both techniques show a shift of sub-T-g transitions (or secondary relaxation peaks) toward the high-temperature region from -140 to -45 degrees C. Thus, this paper outlines the usage of different solid-state characterization techniques in understanding the different molecular dynamics present in the polymer, drug, and their interactions in ASDs with the integrated information obtained from individual techniques.}, language = {en} } @article{VermaMatijevičDenkeretal.2021, author = {Verma, Meetu and Matijevič, Gal and Denker, Carsten and Diercke, Andrea and Dineva, Ekaterina Ivanova and Balthasar, Horst and Kamlah, Robert and Kontogiannis, Ioannis and Kuckein, Christoph and Pal, Partha S.}, title = {Classification of high-resolution Solar H alpha spectra using t-distributed stochastic neighbor embedding}, series = {The astrophysical journal : an international review of spectroscopy and astronomical physics}, volume = {907}, journal = {The astrophysical journal : an international review of spectroscopy and astronomical physics}, number = {1}, publisher = {Institute of Physics Publ.}, address = {London}, issn = {1538-4357}, doi = {10.3847/1538-4357/abcd95}, pages = {14}, year = {2021}, abstract = {The H alpha spectral line is a well-studied absorption line revealing properties of the highly structured and dynamic solar chromosphere. Typical features with distinct spectral signatures in H alpha include filaments and prominences, bright active-region plages, superpenumbrae around sunspots, surges, flares, Ellerman bombs, filigree, and mottles and rosettes, among others. This study is based on high-spectral resolution H alpha spectra obtained with the Echelle spectrograph of the Vacuum Tower Telescope (VTT) located at Observatorio del Teide, Tenerife, Spain. The t-distributed stochastic neighbor embedding (t-SNE) is a machine-learning algorithm, which is used for nonlinear dimensionality reduction. In this application, it projects H alpha spectra onto a two-dimensional map, where it becomes possible to classify the spectra according to results of cloud model (CM) inversions. The CM parameters optical depth, Doppler width, line-of-sight velocity, and source function describe properties of the cloud material. Initial results of t-SNE indicate its strong discriminatory power to separate quiet-Sun and plage profiles from those that are suitable for CM inversions. In addition, a detailed study of various t-SNE parameters is conducted, the impact of seeing conditions on the classification is assessed, results for various types of input data are compared, and the identified clusters are linked to chromospheric features. Although t-SNE proves to be efficient in clustering high-dimensional data, human inference is required at each step to interpret the results. This exploratory study provides a framework and ideas on how to tailor a classification scheme toward specific spectral data and science questions.}, language = {en} }