50 research outputs found
Assessing students’ epistemic beliefs related to professional and school science
The school context, like other influences, affects the development of students’ epistemic beliefs (EBs), with theoretical conceptualizations suggesting a distinction between EBs related to professional and school science. However, empirical studies rarely address this distinction, and instruments separately assessing these EBs are not available. We address this research gap by providing a new questionnaire that is based on the established instrument by Conley et al. (2004) and which uses pairs of analogous items referring to the contexts of professional and school science. We succeeded in simultaneously assessing students’ EBs with reliable scales that allow for direct comparisons. Cross-sectional data is reported from a cohort study (N = 405) in grades 6 (n = 132), 8 (n = 167) and 10 (n = 106) that showed higher agreement with the scales related to professional science as well as higher agreement in higher grade levels. We further discuss methodological aspects of scale-formation, and highlight promising implementations of our questionnaire that future research could benefit from
Influence of Conductive Additives and Binder on the Impedance of Lithium-Ion Battery Electrodes: Effect of Morphology
Most cathode materials for lithium ion batteries exhibit a low electronic conductivity. Hence, a significant amount of conductive graphitic additives are introduced during electrode production. The mechanical stability and electronic connection of the electrode is enhanced by a mixed phase formed by the carbon and binder materials. However, this mixed phase, the carbon binder domain CBD , hinders the transport of lithium ions through the electrolyte pore network. Thus, reducing the performance at higher currents. In this work we combine microstructure resolved simulations with impedance measurements on symmetrical cells to identify the influence of the CBD distribution. Microstructures of NMC622 electrodes are obtained through synchrotron X ray tomography. Resolving the CBD using tomography techniques is challenging. Therefore, three different CBD distributions are incorporated via a structure generator. We present results of microstructure resolved impedance spectroscopy and lithiation simulations, which reproduce the experimental results of impedance spectroscopy and galvanostatic lithiation measurements, thus, providing a link between the spatial CBD distribution, electrode impedance, and half cell performance. The results demonstrate the significance of the CBD distribution and enable predictive simulations for battery design. The accumulation of CBD at contact points between particles is identified as the most likely configuration in the electrodes under consideratio
Clinical and genetic analysis of 29 Brazilian patients with Huntington’s disease-like phenotype
Huntington’s disease (HD) is a neurodegenerative disorder characterized by chorea,
behavioral disturbances and dementia, caused by a pathological expansion of the CAG
trinucleotide in the HTT gene. Several patients have been recognized with the typical HD
phenotype without the expected mutation. The objective of this study was to assess the
occurrence of diseases such as Huntington’s disease-like 2 (HDL2), spinocerebellar ataxia
(SCA) 1, SCA2, SCA3, SCA7, dentatorubral-pallidoluysian atrophy (DRPLA) and choreaacanthocytosis
(ChAc) among 29 Brazilian patients with a HD-like phenotype. In the group
analyzed, we found 3 patients with HDL2 and 2 patients with ChAc. The diagnosis was not
reached in 79.3% of the patients. HDL2 was the main cause of the HD-like phenotype in
the group analyzed, and is attributable to the African ancestry of this population. However,
the etiology of the disease remains undetermined in the majority of the HD negative
patients with HD-like phenotype.
Key words: Huntington’s disease, Huntington’s disease-like, chorea-acanthocytosis,
Huntington’s disease-like 2
Cellular and humoral immune responses to SARS-CoV-2 vaccination in patients after CD19.CAR-T cell therapy
Influence of fuel properties on fundamental spray characteristics and soot emissions using different tailor-made fuels from biomass
This work evaluates the potential of some new biomass-derived fuels as candidates for compression ignition
operation. Thus, fundamental spray characteristics related to fuel vaporization and fuel/air mixing
process for 2-Methyltetrahydrofuran, Di-n-butyl ether and 1-octanol has been studied and compared
with conventional EN590 Diesel fuel. For this purpose, OH⁄ chemiluminescence and shadowgraphy measurements
in a high pressure chamber as well as 1D simulations with a spray model have been carried
out at different operating conditions representative of the NEDC driving cycle. Finally, measured soot
emissions in the single-cylinder engine were presented and discussed.
Results from the high pressure chamber presented very good agreement in terms of liquid length and
vapor penetration with simulation results. Thus, some analytical expressions related to macroscopic
spray characteristics have been proposed and validated experimentally for all four fuels. Finally, the
single-cylinder engine results confirmed the relevant role of soot formation on final emissions for
1-octanol and 2-MTHF. In addition, DNBE showed greater soot oxidation potential than diesel and other
TMFB candidates.This work was performed as part of the Cluster of Excellence "Tailor-Made Fuels from Biomass", which is funded by the Excellence Initiative by the German federal and state governments. Simulation works have been partially funded by Spanish government under the grant "Jose Castillejo" (CAS12/000097).García Martínez, A.; Monsalve Serrano, J.; Heuser, B.; Jakob, M.; Kremer, F.; Pischinger, S. (2016). Influence of fuel properties on fundamental spray characteristics and soot emissions using different tailor-made fuels from biomass. Energy Conversion and Management. 108:243-254. https://doi.org/10.1016/j.enconman.2015.11.010S24325410