Refine
Year of publication
Document Type
- Conference Proceeding (1089)
- Article (unreviewed) (558)
- Article (reviewed) (529)
- Part of a Book (453)
- Book (222)
- Other (138)
- Contribution to a Periodical (123)
- Patent (94)
- Report (62)
- Letter to Editor (30)
Conference Type
- Konferenzartikel (856)
- Konferenz-Abstract (153)
- Sonstiges (40)
- Konferenz-Poster (31)
- Konferenzband (13)
Language
- German (1733)
- English (1594)
- Other language (5)
- Russian (3)
- Multiple languages (2)
- French (1)
- Spanish (1)
Has Fulltext
- no (3339) (remove)
Keywords
- Digitalisierung (39)
- RoboCup (32)
- Dünnschichtchromatographie (26)
- Arbeitszeugnis (22)
- Finite-Elemente-Methode (22)
- Energieversorgung (21)
- Kommunikation (21)
- Management (19)
- Industrie 4.0 (18)
- Machine Learning (18)
Institute
- Fakultät Maschinenbau und Verfahrenstechnik (M+V) (786)
- Fakultät Medien und Informationswesen (M+I) (bis 21.04.2021) (717)
- Fakultät Elektrotechnik und Informationstechnik (E+I) (bis 03/2019) (704)
- Fakultät Wirtschaft (W) (558)
- Fakultät Elektrotechnik, Medizintechnik und Informatik (EMI) (ab 04/2019) (390)
- INES - Institut für nachhaltige Energiesysteme (178)
- Fakultät Medien (M) (ab 22.04.2021) (172)
- ivESK - Institut für verlässliche Embedded Systems und Kommunikationselektronik (133)
- IMLA - Institute for Machine Learning and Analytics (72)
- ACI - Affective and Cognitive Institute (57)
Open Access
- Closed Access (1241)
- Open Access (865)
- Closed (532)
- Bronze (189)
- Diamond (53)
- Gold (11)
- Hybrid (11)
- Grün (7)
This paper presents a practice and science orientated education approach for freshman students of interdisciplinary bachelor engineering degree programs. This approach is meant to enhance the motivation and success of freshman students during their whole study. The education approach is called Fit4PracSis (Fit for Practice and Sciences) It was started to develop, set up and establish an education approach, which is building a relationship to students' future profession and to scientific working during the introductory study phase. The freshman students will be trained early in important skills, which are necessary for achieving the final degree successfully and handling of future business and research activities.
In this paper we present a model of the discharge of a lithium–oxygen battery with aqueous electrolyte. Lithium–oxygen batteries (Li–O2) have recently received great attention due to their large theoretical specific energy. Advantages of the aqueous design include the stability of the electrolyte, the long experience with gas diffusion electrodes (GDEs), and the solubility of the reaction product lithium hydroxide. However, competitive specific energies can only be obtained if the product is allowed to precipitate. Here we present a dynamic one-dimensional model of a Li–O2 battery including a GDE and precipitation of lithium hydroxide. The model is parameterized using experimental data from the literature. We demonstrate that GDEs remove power limitations due to slow oxygen transport in solutions and that lithium hydroxide tends to precipitate on the anode side. We discuss the system architecture to engineer where nucleation and growth predominantly occurs and to optimize for discharge capacity.
Compact solid discharge products enable energy storage devices with high gravimetric and volumetric energy densities, but solid deposits on active surfaces can disturb charge transport and induce mechanical stress. In this Letter, we develop a nanoscale continuum model for the growth of Li2O2 crystals in lithium–oxygen batteries with organic electrolytes, based on a theory of electrochemical nonequilibrium thermodynamics originally applied to Li-ion batteries. As in the case of lithium insertion in phase-separating LiFePO4 nanoparticles, the theory predicts a transition from complex to uniform morphologies of Li2O2 with increasing current. Discrete particle growth at low discharge rates becomes suppressed at high rates, resulting in a film of electronically insulating Li2O2 that limits cell performance. We predict that the transition between these surface growth modes occurs at current densities close to the exchange current density of the cathode reaction, consistent with experimental observations.
In the dual membrane fuel cell (DM-Cell), protons formed at the anode and oxygen ions formed at the cathode migrate through their respective dense electrolytes to react and form water in a porous composite layer called dual membrane (DM). The DM-Cell concept was experimentally proven (as detailed in Part I of this paper). To describe the electrochemical processes occurring in this novel fuel cell, a mathematical model has been developed which focuses on the DM as the characteristic feature of the DM-Cell. In the model, the porous composite DM is treated as a continuum medium characterized by effective macro-homogeneous properties. To simulate the polarization behavior of the DM-Cell, the potential distribution in the DM is related to the flux of protons and oxygen ions in the conducting phases by introducing kinetic and transport equations into charge balances. Since water pressure may affect the overall formation rate, water mass balances across the DM and transport equations are also considered. The satisfactory comparison with available experimental results suggests that the model provides sound indications on the effects of key design parameters and operating conditions on cell behavior and performance.
Adsorption of N2 and CO2 on Activated Carbon, AlO(OH) Nanoparticles, and AlO(OH) Hollow Spheres
(2015)
Adsorption behaviors of nitrogen and CO2 on Norit R1 Extra and AlO(OH) nanoparticles and hollow spheres were measured under different temperature and pressure conditions using a magnetic suspension balance. Independent from the substrate investigated, all isotherms increase at lower pressure, reach a maximum, and then decrease with increasing pressure. In addition, selected experimental data were correlated with different model approaches and compared with reliable literature data. In case of CO2 on AlO(OH), capillary condensation was observed at two defined temperatures. The results suggest that the conversion of the liquid into a supercritical adsorbate phase does not take place suddenly.
Both German and French Air-Source Heat Pump (ASHP) markets have been enjoying an overall upwards trend for many years but, nevertheless, they remain merely slightly penetrated. In terms of market players and their share, the French market is aptly diversified, whereas the German one, being utterly dominated by one single manufacturer, is badly in need of some diversification. At the same time Korean ASHP manufacturers are targeting the French but not German ASHP market. The main purpose of the paper is to find out likely reasons for their one-sided engagement, primarily those associated with the ASHP technology and its system-related aspects.
A 2D-separation of 16 polyaromatic hydrocarbons (PAHs) according to the Environmental Protecting Agency (EPA) standard was introduced. Separation took place on a TLC RP-18 plate (Merck, 1.05559). In the first direction, the plate was developed twice using n-pentane at −20°C as the mobile phase. The mixture acetonitrile-methanol-acetone-water (12:8:3:3, v/v) was used for developing the plate in the second direction. Both developments were carried out over a distance of 43 mm. Further on in this publication, a specific and very sensitive indication method for benzo[a]pyrene and perylene was presented. The method can detect these hazardous compounds even in complicated PAH mixtures. These compounds can be quantified by a simple chemiluminescent reaction with a limit of detection (LOD) of 48 pg per band for perylene and 95 pg per band for benzo[a]pyrene. Although these compounds were separated from all other PAHs in the standard, a separation of both compounds was not possible from one another. The method is suitable for tracing benzo[a]pyrene and/or perylene. The proposed chemiluminescence screening test on PAHs is extremely sensitive but may indicate a false positive result for benzo[a]pyrene.