107 research outputs found
Piezo-actuated hybrid tool for the micro structuring of cylinder liners in an energy-efficient process chain
Automotive traffic is one of the largest drivers of greenhouse gas emissions in Europe. In order to achieve energy savings both, during the process and during the use phase of passenger cars, the powertrain components and their process chains will be optimized as part of the "Powertrain 2025" project. For this purpose, the implementation of an innovative process chain for the production of non-circular, microstructured and honed cylinder liners is being researched. Therefore, the paper introduces a new piezo-actuated hybrid tool, which was developed for the combination of non-circular turning and microstructuring of the cylinder liners in one tool. An integrated optical distance sensor measures after the process the workpiece geometry. This is used for quality control and as an input value for a process chain control that optimizes the process parameters and thus reduces the reject rate. After a short introduction of the new, energy-efficient process chain, the paper focuses on the concept and dimensioning of the new hybrid tool
Synchrotron radiation based studies of complex molecules on surfaces
In this thesis two single molecule magnets based on the dodecamanganese (III, IV) cluster, with either benzoate or terphenyl-4-carboxylate ligands have been studied on the Au(111) and rutile TiO2(110) surfaces. We have used in situ electrospray deposition to produce a series of surface coverages from a fraction of a monolayer to multilayer films in both cases. X-ray absorption spectroscopy measured at the Mn L-edge (Mn 2p) has been used to study the effect of adsorption on the oxidation states of the manganese atoms in the core. In the case of the enzoate-functionalized complex, reduction of the manganese metal centres is observed due to the interaction of the manganese core with the underlying surface. In the case of terphenyl-4 carboxylate, the presence of this much larger ligand prevents the magnetic core from interacting with either the gold or the titanium dioxide surfaces and the characteristic Mn3+ and Mn4+ oxidation states necessary for magnetic behaviour are preserved.
In contrast to the single molecule magnets where no charge transfer between the molecules and the substrates or within the molecules themselves were wanted, the molecules of bi isonicotinic acid and the giant zinc porphyrin nanorings have been studied on rutile TiO2(110) and Au(111) surfaces in the pursuit of charge transfer. In the case of the bi-isonicotinic acid it is studied on the rutile TiO2(110) where the technique of resonant inelastic X-ray scattering was been employed. Here we introduce the core-hole clock implementation to estimate the charge transfer from the molecule to the substrate. We verify previous results of ultrafast charge transfer in the sub-femtosecond regime (2.9 ± 0.3 femtoseconds) out of the LUMO+1 orbital. When the higher lying state of the LUMO+2 state is probed charge transfer out of this state and to the substrate is possibly there, but it is not possible to resolve it since it is masked by other effects originating from the inelastic scattering of the system. Furthermore, we see potential charge transfer within the molecule itself and new states observed in the inelastic scattering.
Finally, zinc porphyrin nanorings were investigated on two surfaces of rutile TiO2(110) and Au(111). The techniques used here were X-ray photoemission spectroscopy and resonant photoemission spectroscopy. When the rutile TiO2(110) surface was employed hardly any participator decay was present suggesting charge transfer within the molecule itself or to the surface. This is further backed up by the fact that all of the core-excited unoccupied states are found to overlap energetically with the unoccupied states of the substrate, facilitating charge transfer out all the core-excited states. In the case of the Au(111) surface somewhat similar results are found, having all the core-excited states of the molecule located within the unoccupied states of the substrate, which again will facilitate charge transfer out all the core-excited states of the molecule. When the Au(111) substrate was employed the technique of near edge X-ray absorption fine structure was used to investigate the geometric orientation of the molecule on the surface. With the result of 86◦ ± 10◦ to the surface normal we verify previous scanning tunneling microscopy measurement that the zinc porphyrin nanorings will take a at lying orientation on the gold substrate
Synchrotron radiation based studies of complex molecules on surfaces
In this thesis two single molecule magnets based on the dodecamanganese (III, IV) cluster, with either benzoate or terphenyl-4-carboxylate ligands have been studied on the Au(111) and rutile TiO2(110) surfaces. We have used in situ electrospray deposition to produce a series of surface coverages from a fraction of a monolayer to multilayer films in both cases. X-ray absorption spectroscopy measured at the Mn L-edge (Mn 2p) has been used to study the effect of adsorption on the oxidation states of the manganese atoms in the core. In the case of the enzoate-functionalized complex, reduction of the manganese metal centres is observed due to the interaction of the manganese core with the underlying surface. In the case of terphenyl-4 carboxylate, the presence of this much larger ligand prevents the magnetic core from interacting with either the gold or the titanium dioxide surfaces and the characteristic Mn3+ and Mn4+ oxidation states necessary for magnetic behaviour are preserved.
In contrast to the single molecule magnets where no charge transfer between the molecules and the substrates or within the molecules themselves were wanted, the molecules of bi isonicotinic acid and the giant zinc porphyrin nanorings have been studied on rutile TiO2(110) and Au(111) surfaces in the pursuit of charge transfer. In the case of the bi-isonicotinic acid it is studied on the rutile TiO2(110) where the technique of resonant inelastic X-ray scattering was been employed. Here we introduce the core-hole clock implementation to estimate the charge transfer from the molecule to the substrate. We verify previous results of ultrafast charge transfer in the sub-femtosecond regime (2.9 ± 0.3 femtoseconds) out of the LUMO+1 orbital. When the higher lying state of the LUMO+2 state is probed charge transfer out of this state and to the substrate is possibly there, but it is not possible to resolve it since it is masked by other effects originating from the inelastic scattering of the system. Furthermore, we see potential charge transfer within the molecule itself and new states observed in the inelastic scattering.
Finally, zinc porphyrin nanorings were investigated on two surfaces of rutile TiO2(110) and Au(111). The techniques used here were X-ray photoemission spectroscopy and resonant photoemission spectroscopy. When the rutile TiO2(110) surface was employed hardly any participator decay was present suggesting charge transfer within the molecule itself or to the surface. This is further backed up by the fact that all of the core-excited unoccupied states are found to overlap energetically with the unoccupied states of the substrate, facilitating charge transfer out all the core-excited states. In the case of the Au(111) surface somewhat similar results are found, having all the core-excited states of the molecule located within the unoccupied states of the substrate, which again will facilitate charge transfer out all the core-excited states of the molecule. When the Au(111) substrate was employed the technique of near edge X-ray absorption fine structure was used to investigate the geometric orientation of the molecule on the surface. With the result of 86◦ ± 10◦ to the surface normal we verify previous scanning tunneling microscopy measurement that the zinc porphyrin nanorings will take a at lying orientation on the gold substrate
Impact of the "Guidelines for infection prevention in dentistry" (2006) by the Commission of Hospital Hygiene and Infection Prevention at the Robert Koch-Institute (KRINKO) on hygiene management in dental practices – analysis of a survey from 2009
Aim: To assess trends in hygiene management in dental practices in comparison to an earlier survey in 2002/2003 and to point out key aspects for future efforts
Markedsgæster blev klogere på biodiversitet på Stenalt Landbrug
Artikel i Nyhedsbrev Fra Innovationscenter for Økologisk Landbrug (ICOEL) om Efterårsmarked på Stenalt 2022, hvor medarbejdere fra ICOEL deltog i forbindelse med Organic+ projektet (biodiversitets-stand).
Artiklen fortæller om denne biodiversitets-stand arrangeret i samarbejde mellem Organic+ projektdeltagere (medarbejdere fra Aarhus Universitet og ICOEL sammen med Stenalts driftsleder).
Artiklen forklarer formålet med Organic+ projektet og dets sammenhæng med de økologiske landbrug.
Den fortæller også om Stenalts landbrug og markdrift
Adsorption and charge transfer interactions of bi-isonicotinic acid on Ag(111)
The adsorption and charge transfer dynamics of the organic molecule bi-isonicotinic acid (4,4′-dicarboxy-2,2′-bipyridine) on single crystal Ag(111) has been studied using synchrotron radiation-based photoemission, x-ray absorption and resonant core spectroscopies. Measurements for multilayer and monolayer coverage are used to determine the nature of the molecule-surface interactions and the molecular orientation. An experimental density of states for the monolayer with respect to the underlying metal surface is obtained by combining x-ray absorption spectroscopy at the N 1s edge and valence photoemission to measure the unoccupied and occupied valence states, respectively. This shows that the lowest unoccupied molecular orbital in the core-excited state lies energetically below the Fermi level of the surface allowing charge transfer from the metal into this orbital. Resonant photoelectron spectroscopy was used to probe this charge transfer in the context of super-spectator and super-Auger electron transitions. The results presented provide a novel interpretation of resonant core-level spectroscopy to explore ultra-fast charge transfer between an adsorbed organic molecule and a metal surface through the observation of electrons from the metal surface playing a direct role in the core-hole decay of the core-excited molecule
Medien und Berufsvorstellungen von Kindern: eine experimentelle Studie zum Einfluss von Kinderbüchern auf das Berufsspektrum von Kindergartenkindern
"Der Beitrag thematisiert zunächst den Stand der beruflichen Orientierung von Jugendlichen sowie die pädagogischen Bemühungen beim Übergang Schule-Beruf, insbesondere im Hinblick auf eine Erweiterung des häufig engen Spektrums von Berufen, die bei der Berufswahl berücksichtig werden. Dabei richten sich die Bestrebungen, diesem Problem entgegenzuwirken, bislang vor allem auf Jugendliche. Anschließend wird anhand vorliegender Ergebnisse aus der Medienforschung diskutiert, in welcher Weise Massenmedien Einfluss auf Wissen und Vorstellungen von Berufen nehmen können. Die vorgestellte Studie geht schließlich der Frage nach, ob kindgerechte Medien in der Lage sind, das Spektrum bekannter Berufe bereits im Kindergartenalter substanziell zu erweitern. Dazu werden Daten aus einem zweimonatigen Experiment vorgestellt, in dem Kinderbücher mit Berufsbezug über mehrere Wochen in Kitas vorgelesen wurden. Die Kinder der Treatmentgruppe kannten nach der Lektüre mehr als doppelt so viele Berufe wie vorher und der Zuwachs ließ sich anhand der genannten Berufe eindeutig auf die gelesenen Bücher zurückführen, wohingegen sich in der Kontrollgruppe keine Vorher-Nachher-Unterschiede zeigten." (Autorenreferat)"The aim of this study is to examine the influence of children's books on the vocational knowledge of kindergarten children. The article discusses the relationship of media usage and vocational/occupational image and whether the relationship between the two constructs is causal. Furthermore, an overview of the vocational orientation process of adolescents with an emphasis on the problematic school to work transition is given. In addition, governmental and educational efforts to support this transition are discussed. Based on this framework, the article discusses whether occupational knowledge of younger children can be influenced by media. A pre-posttest experimental design with guideline-based interviews with kindergarten children is implemented to test this notion. During a two-month experimental period, kindergarten children were confronted with child-appropriate books, which were clearly related to occupations. The results indicate a significant effect of age-appropriate media usage on occupational knowledge especially on the vocational spectrum. Children in the treatment group reported twice as many occupations in the posttest compared to the pretest. Based on the results, this effect can be attributed to the stimulus material." (author's abstract
Online Community Engagement Enhances Service Learning
DePaul University’s Steans Center for Community-Based Service Learning created a program called Online Community Engagement (OCE) to safely connect students with communities during the COVID-19 pandemic. As this article says, “OCE provided self- directed modules including reading materials and videos for students focused on issues such as mental health, immigration, community organizing, police accountability, and gentrification. The modules culminated with a live online events on Fridays featuring guests from DePaul and Chicago communities.” OCE proved highly successful, especially because it provided a way for students to meet community organizers. The article profiles some of the most salient lessons featured in OCE as well as student feedback about them. OCE will remain part of the post-pandemic curriculum
Naturhensyn i økologisk landbrug øger biodiversiteten
Det er en udfordring, at overskue og vælge hvilke biodiversitetstiltag, der fungerer bedst i forskellige landbrugslandskaber.
Projektet Organic+, hvis mål er at udvikle og afprøve et værktøj til beslutningsstøtte til at vejlede landmænd i valget af biodiversitetstiltag og deres placering i landskabet, inviterede torsdag d. 9. juni projektpartnere og interesserede landmænd fra økologiske bedrifter til workshop på Stenalt Land- og Skovbrug i Ørsted. Her præsenterede Bent Rasmussen fra Innovationscenter for Økologisk Landbrug (ICØL) et oplæg om biodiversitet i landbruget, og efterfølgende diskuterede deltagerne henholdsvis biodiversitetstiltag i bedrifterne, samt kommunikation og formidling. Dagen afsluttedes med en inspirerende markvandring på Stenalts arealer (nyhedsbrev af ICØL
Exploring ultra-fast charge transfer and vibronic coupling with N 1s RIXS maps of an aromatic molecule coupled to a semiconductor
We present for the first time two-dimensional resonant inelastic x-ray scattering (RIXS) maps of multilayer and monolayer biisonicotinic acid adsorbed on the rutile TiO2(110) single crystal surface. This enables the elastic channel to be followed over the lowest unoccupied molecular orbitals resonantly excited at the N 1s absorption edge. The data also reveals ultra-fast intramolecular vibronic coupling, particularly during excitation into the LUMO-derived resonance. Both elastic scattering and the vibronic coupling loss features are expected to contain the channel in which the originally excited electron is directly involved in the core-hole decay process. This allows RIXS data for a molecule coupled to a wide bandgap semiconductor to be considered in the same way as the core-hole clock implementation of resonant photoemission spectroscopy (RPES). However, contrary to RPES measurements, we find no evidence for depletion of the participator channel under the conditions of ultra-fast charge transfer from the molecule to the substrate densities of states, on the timescale of the core-hole lifetime. These results suggest that the radiative core-hole decay processes in RIXS are not significantly modified by charge transfer on the femtosecond timescale in this system
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