University of Education Freiburg

The direct hydrogenation and conversion of CO 2 to dimethyl ether (DME) combines CO 2 valorization and climate change mitigation. This process requires a bifunctional catalyst (CtM//MtD) with a CO 2 ‐to‐MeOH (CtM) and a MeOH‐to‐DME (MtD) component, in which the CuO/ZnO/ZrO 2 (CZZ) CtM‐catalyst is better suited for CO 2 rich feed gases than the industrial CuO/ZnO/Al 2 O 3 (CZA) catalyst optimized for classical CO/H 2 syngas. Dehydration MtD‐catalysts include commercial zeolites (ZSM5, FER) and heteropolyacid‐coated alumina and zirconia (HPA@Al, HPA@Zr). However, ZrO 2 is significantly more expensive than Al 2 O 3 . Therefore, a novel fluorinated CuO/ZnO/MgO (CZMg‐F) system was tested for direct DME synthesis under gas hourly space time velocities (GHSVs) of 4950−158000 NL kg cat −1 h −1 at 250°C and 40 bar in a CO 2 /3H 2 stream. The study showed that CZMg‐F combined with ZSM5 and FER achieved similar activities to CZZ‐based catalysts. CZMg‐F//HPA@Zr exhibit superior DME selectivity (50%) at high GHSV, outperforming all other tested CZMg‐F and CZZ hybrid catalysts. The only exception was CZMg‐F//HPA@Al, which exhibits significantly lower DME activity, most likely due to unfavorable interactions with Al 2 O 3 . Compared to the low activity of CZZ//FER at high GHSV, CZMg‐F//FER showed much higher DME activity, making CZMg‐F a better alternative in combination with FER at high GHSV.

Learning journals are a powerful tool to foster deep comprehension and lasting learning. However, the effectiveness of prompts in supporting high-school students’ learning journals is understudied. Similarly, the role of the production medium needs to be addressed. We investigated the effects of cognitive and metacognitive prompts on learning strategy use and learning outcomes as well as the influence of the medium (written vs. spoken journals). High school students ( N = 163) from social science academic track schools in Germany participated. Participants watched a video-lecture on cognitive load theory and generated either a written or a spoken learning journal entry with or without prompts. A control group engaged in repeated reading and underlining of the lecture text. Participants’ comprehension was tested one day later and their retention seven days later. Learning journals were analyzed for cognitive and metacognitive learning strategies. Spoken journals yielded larger learning outcomes than written journals both in the post-test and the repeated post-test. Spoken journals were four times longer than written journals. Facilitated text production through spoken journals boosted the application of cognitive and metacognitive strategies. Metacognitive prompts boosted metacognitive strategy use, but cognitive prompts failed to improve cognitive strategy use. Cognitive strategies improved learning outcomes directly, but metacognitive strategies only indirectly via cognitive strategies. Evidently, the oral medium is a powerful strategy activator that can be combined with other strategy activators, such as prompts, to facilitate learning strategy use in learning journals and thereby improve deep comprehension and lasting learning. • Spoken learning journals yielded better comprehension than written ones. • Oral medium significantly boosted the application of learning strategies. • Learning strategies mediated the impact of medium on learning outcomes. • Oral medium's effectiveness may be due to lower production and formulation costs. • Prompts improved use of metacognitive strategies especially in spoken journals.

Abstract The number line is frequently used to represent number magnitudes, including fractions. Visual hatchmarks can enhance performance in number line estimation tasks, but their effectiveness may depend on specific item features. It remains unclear how hatchmarks influence individuals’ use of the benchmark strategy, in which reference points are used for orientation. This study addresses this gap using eye tracking. We recorded 63 adults’ eye movements while they solved fraction number line estimation tasks on a computer. Line segments were marked with 0 and 1 at the endpoints and were presented in three hatchmark conditions: no hatchmarks, third hatchmarks (at 1/3 and 2/3), and quarter hatchmarks. Participants were asked to find the correct position of a symbolic fraction shown above the line. Measures of accuracy, reaction time, and fixation duration suggest that participants used mental benchmarks regardless of whether the number line included visual hatchmarks. When hatchmarks were available, participants looked at them and were, overall, more accurate than without hatchmarks. The beneficial effect of hatchmarks was more pronounced when hatchmarks corresponded to fraction denominators (e.g., 5/9 in the third-hatchmark condition) compared to when they did not (e.g., 5/9 in the quarter-hatchmark condition). However, hatchmarks led to longer reaction times, especially when they did not correspond to fraction denominators. This study provides a nuanced picture of the effects of hatchmarks on number line estimation. Hatchmarks can increase accuracy but can also make participants less efficient. In instruction, support measures such as hatchmarks should be carefully selected to achieve the intended effects.

• Teachers use technology to practice, present, motivate, or without clear function. • Teachers reveal notable inter-individual differences in teaching practices. • Teachers differ in how they explain content, implement rules, and select materials. • There is considerable variation in integrating digital technology in the classroom. • Some teachers use the full potential of digital technology, while others do less. Digital technology has the potential to improve student learning, especially in mathematics. However, the extent to which students benefit from technology largely depends on how it is integrated into instruction. Nevertheless, little is known about how teachers implement digital technology in the classroom. This study examines how 14 in-service teachers use a digital tool for teaching fractions in 15–20 lessons. We used classroom observation to identify teaching practices, and cluster analysis to group them into teaching approaches. Four main approaches of teaching with digital technology emerged: (i) Practicing , where teachers used various features of the tool to make students practice the learning content, (ii) Presenting , where teachers used the tool predominantly to present the learning content but did not utilize many features, (iii) Motivating Students , where the tool and especially its game-like features were used as a reward for students, and (iv) Low-Guidance , where the teacher did not provide guidance for students how to use the tool. Teaching practices varied between these approaches in several dimensions, for example in how teachers explained the learning content, how they implemented rules, and which learning materials they selected. The findings highlight large variation in integrating even one and the same digital tool in the mathematics classroom. We identified teaching approaches for technology-enhanced learning settings that can inform future research investigating how technology implementation influences student learning. These approaches may also guide the design of professional development programs that support teachers in developing effective strategies for integrating digital technology into their instruction.

EP1.2, e-Poster Terminal 1, September 3, 2025, 13:05 - 13:55AimsHealth literacy (HL) enables individuals to make informed health decisions, including regarding infectious diseases. Refugees are at heightened risk of low HL due to language barriers, cultural differences, and limited access to reliable health information. They also face higher risk of infectious diseases, including antibiotic-resistant infections. We aimed to assess HL, antibiotic knowledge and use, and relationships between them among adults residing in the initial reception center (Landeserstaufnahmeeinrichtung, LEA) for refugees and asylum seekers in Freiburg, Germany.MethodsWe conducted a cross-sectional study with 107 adult LEA residents, who completed questionnaires in Arabic, Persian, Pashto, Turkish, and English. HL was measured using the HLS-EU-16; antibiotic knowledge and use were assessed using ad hoc questions, based on existing literature. Data were analyzed using descriptive and inferential statistics.ResultsAround half of participants had adequate self-reported HL, while the remainder reported problematic or inadequate HL, reflecting difficulties with finding, understanding, or applying health-related information. Nearly half reported having used antibiotics within the last 6 months; however, knowledge regarding antibiotics was patchy and many participants reported inappropriate antibiotic use (e.g., inadequate duration; storing leftover antibiotics for later use). Lower HL was associated with increased likelihood of inappropriate antibiotic use.ConclusionsThe study demonstrates that HL among LEA residents in Freiburg is heterogeneous and shaped by multiple demographic and contextual factors. The findings underscore the importance of culturally and linguistically tailored health education strategies to improve infection prevention and health outcomes in refugee populations, particularly regarding knowledge about and use of antibiotics.

Plastic pyrolysis aims to process plastic waste into petrochemical feedstocks by addressing waste fractions that are unsuitable for mechanical recycling due to their complex composition. Steam cracking of the resulting pyrolysis oils requires low levels of contaminants, limiting the acceptable contaminant level in feedstocks for chemical recycling. The utilization of pyrolysis oil in entrained-flow gasification (EFG) can overcome this limitation, as EFG is designed to process low-quality feedstocks such as heavy fuel oil (HFO) with high heteroatom content. For process assessment, we developed a flowsheet model for EFG of pyrolysis oil from automotive plastic waste (APW) and carried out a comprehensive life cycle assessment (LCA). HFO and APW pyrolysis oil as feedstocks for EFG show minimal differences regarding process efficiencies. In combination with the pyrolysis step, overall carbon efficiencies of 41% (methanol syngas) and 62% (Oxo syngas) are reached. Despite differing carbon efficiencies, both waste-to-syngas routes show nearly identical net climate change impacts (CCI) of 0.14 kg of CO2e/kg of APW, indicating that the choice of syngas product composition does not significantly influence the CCI. In comparison, the established current practice of incineration with energy recovery (waste-to-energy) causes a CCI that is 1 kg of CO2e/kg of APW higher.