Refine
Year of publication
- 2014 (102) (remove)
Document Type
- Conference Proceeding (58)
- Article (reviewed) (23)
- Article (unreviewed) (12)
- Book (4)
- Bachelor Thesis (2)
- Patent (2)
- Contribution to a Periodical (1)
Conference Type
- Konferenzartikel (41)
- Konferenz-Abstract (10)
- Konferenz-Poster (3)
- Konferenzband (2)
- Sonstiges (2)
Language
- English (102) (remove)
Keywords
- Intelligentes Stromnetz (5)
- Lithiumbatterie (4)
- Produktion (4)
- Elektrolyt (3)
- Netzwerk (3)
- Photonik (3)
- Positronen-Emissions-Tomografie (3)
- RoboCup (3)
- SPECT (3)
- Algorithmus (2)
- Ausbildung (2)
- Design (2)
- Elektrochemie (2)
- Herzkrankheit (2)
- Hochtemperatur (2)
- Katheter (2)
- Kinetik (2)
- Kommunikation (2)
- Maschinenelement (2)
- Nervenheilkunde (2)
- Optik (2)
- Produktentwicklung (2)
- Stahl (2)
- Unity (2)
- standardization (2)
- 3D displays (1)
- 3D modeling (1)
- 3D printing (1)
- Abbreviate Injury Scale (1)
- Absatz (1)
- Accident Analysis (1)
- Advanced Driver Assistance System (1)
- Air Traffic Control (1)
- Analyse (1)
- Anbieter (1)
- Antenne (1)
- Applikation (1)
- Arzneimittel (1)
- Aufbereitung (1)
- Austausch (1)
- BACnet (1)
- Batterie (1)
- Benchmark (1)
- Bioelement (1)
- Car-2-Car communication (1)
- Car-2-X communication (1)
- Car-to-Car-(C2C)-Communication (1)
- Cloud Computing (1)
- Cloud Security (1)
- Cloud Service Provider (1)
- Cloud User (1)
- Cogeneration (1)
- Collision Point (1)
- Communication Systems (1)
- Computerspiel (1)
- Computersysteme (1)
- Cyber Physical Systems, (1)
- DDS (1)
- Data Distribution Service (1)
- Data communications (1)
- Data modeling (1)
- Databases (1)
- Datenbanksystem (1)
- Datenerfassung (1)
- Diffusion (1)
- Drahtloses lokales Netz (1)
- Dünnschichtchromatographie (1)
- Elastische Welle (1)
- Elastizität (1)
- Elektrode (1)
- Elektrofahrzeug (1)
- Energiespeicher (1)
- Energy Management (1)
- Enhanced Security (1)
- Epilepsie (1)
- Equations (1)
- Ermüdung (1)
- Erweitere Realität (1)
- Ethinylestradiol (1)
- Festbett (1)
- Flexibilität (1)
- Formale Beschreibung (1)
- Funktechnik (1)
- Game Development (1)
- Gas (1)
- Gasbehälter (1)
- Gebäudeleittechnik (1)
- Gewerbegebäude (1)
- Grid Integration (1)
- Halswirbelsäule (1)
- Herstellung (1)
- Hybridtechnik (1)
- IEEE802.11p/WAVE (1)
- Implementation (1)
- Implementierung (1)
- Information Systems (1)
- Integrierte Schaltung (1)
- Internet der Dinge (1)
- Internet of Things (1)
- Java <Programmiersprache> (1)
- Kalibrieren (1)
- Katalyse (1)
- Kathode (1)
- Keil (1)
- Keilwelle (1)
- Kernspintomografie (1)
- Kleintiere (1)
- Klimatechnik (1)
- Kommunikationsprotokoll (1)
- Konsum (1)
- Kontrolltheorie (1)
- Langfristige Korrelation (1)
- Laser (1)
- Leistung (1)
- Leistungselektronik (1)
- Lieferung (1)
- Lithium compounds (1)
- Lithium-Ionen-Akkumulator (1)
- Machine-to- Machine-(M2M)-Communication (1)
- Materialwirtschaft (1)
- Mathematical model (1)
- Medizintechnik (1)
- Metallisieren (1)
- Metallorganisches Netzwerk (1)
- Mobile devices (1)
- Natrium-Ionen-Akkumulator (1)
- Neurobiologie (1)
- Neurologie (1)
- Nuklearmedizin (1)
- Oberfläche (1)
- Oberflächenbehandlung (1)
- PV System (1)
- Passives Bauelement (1)
- Patent (1)
- Polymerisation (1)
- Preis (1)
- Prototyp (1)
- Prozessor (1)
- Schnittstelle (1)
- Segmentierung (1)
- Sicherheit (1)
- Simulation (1)
- Spannung (1)
- Spiel (1)
- Spiel-Engine (1)
- Substanz (1)
- Substrates (1)
- Surface acoustic waves (1)
- Symmetrie (1)
- Target Vehicle (1)
- Thermoelektrizität (1)
- Thermomechanik (1)
- Toxizität (1)
- Transport (1)
- Trauma (1)
- Ultraschall (1)
- Unity3D (1)
- VANETs (1)
- VRU eSafety (1)
- Verfahren (1)
- Verkehrsregelung (1)
- Versorgungstechnik (1)
- Verteilung (1)
- Vervielfältigung (1)
- Videogame (1)
- Videospiel (1)
- Vorzeitigkeit (1)
- Web-Applikation (1)
- Wärmepumpe (1)
- Zwischenmodulation (1)
- ad hoc networks (1)
- car-to-car communication (1)
- data replication (1)
- distributed systems (1)
- e-learning (1)
- emulation (1)
- inter-vehicle communication (1)
- intra-vehicle communication (1)
- kanal (1)
- localization (1)
- middleware (1)
- performance analysis (1)
- performance evaluation (1)
- railways (1)
- real time (1)
- secondary surveillance radar (1)
- service engineering (1)
- service research (1)
- subsystem design (1)
- vehicular networks (1)
- wireless access networks (1)
- wireless sensor networks (1)
- wireless vehicular network (1)
- Überwachung (1)
Institute
- Fakultät Elektrotechnik und Informationstechnik (E+I) (bis 03/2019) (65)
- Fakultät Maschinenbau und Verfahrenstechnik (M+V) (20)
- Fakultät Medien und Informationswesen (M+I) (bis 21.04.2021) (12)
- Fakultät Wirtschaft (W) (11)
- INES - Institut für nachhaltige Energiesysteme (11)
- ivESK - Institut für verlässliche Embedded Systems und Kommunikationselektronik (6)
- IUAS - Institute for Unmanned Aerial Systems (2)
- POIM - Peter Osypka Institute of Medical Engineering (2)
Open Access
- Open Access (31)
- Closed Access (30)
- Closed (21)
- Bronze (6)
Pressure dynamics in metal-oxygen (metal-air) batteries: a case study on sodium superoxide cells
(2014)
Electrochemical reactions in metal–oxygen batteries come along with the consumption or release of gaseous oxygen. We present a novel methodology for investigating electrode reactions and transport phenomena in metal–oxygen batteries by measuring the pressure dynamics in an enclosed gas reservoir above the oxygen electrode. The methodology is exemplified by a room-temperature sodium–oxygen battery forming sodium superoxide (NaO2) in an electrolyte of diethylene glycol dimethyl ether (diglyme) and sodium trifluoromethanesulfonate (NaOSO2CF3, NaOTf). The experiments are supported by microkinetic simulations with a one-dimensional multiphysics continuum model. During galvanostatic cycling over 30 cycles, a constant oxygen consumption/release rate is observed upon discharge/charge. The number of transferred electrons per oxygen molecule is calculated to 1.01 ± 0.02 and 1.03 ± 0.02 for discharge and charge, respectively, confirming the nature of the oxygen reaction product as superoxide O2–. The same ratio is observed in cyclic voltammetry experiments with low scan rate (<1 mV/s). However, at higher scan rates, the ratio increases as a result of oxygen transport limitations in the electrolyte. We introduce electrochemical pressure impedance spectroscopy (EPIS) for simultaneously analyzing current, voltage, and pressure of electrochemical cells. Pressure recording significantly increases the sensitivity of impedance toward oxygen transport properties of the porous electrode systems. In addition, we report experimental data on the diffusion coefficient and solubility of oxygen in electrolyte solutions as important parameters for the microkinetic models.
Aqueous lithium–oxygen batteries are promising candidates for electric energy storage. In this paper we present and discuss a multiphase continuum model of an aqueous lithium–oxygen single cell including reactions and transport in a porous gas diffusion electrode (GDE). The model is parameterized using in-house half-cell experiments and available literature data on aqueous electrolytes. We validate our transport model with cyclic voltammetry and electrochemical impedance spectroscopy measurements over a wide range of temperatures (25, 40, 55 °C) and electrolyte concentrations (0.1–2 M). We observe very good agreement between simulations and measurements during oxygen reduction conditions. A sensitivity analysis of the validated model demonstrates the influence of the porous structure on GDE performance and gives directions for the future development of electrodes.
Todays‘ traffic support environments are distributed by nature. In many cases the monitoring, control and guidance of traffic is effected by a federation of coordinating centers, often managed by different organizations, using differing local IT technology and system architecture. Despite the federative character of such systems, maintenance of a consistent overall traffic state is indispensable for a safe operation. This project develops a new type of middleware supporting federative systems
in the domain of Air Traffic Control (ATC), using OMG‘s DDS (Data Distribution Service) standard as contributor.
Introduction: Radiofrequency ablation allows successful treatment of most supraventricular reentrant and focal tachycardias and an increasing number of ventricular tachycardias. Different catheter tips are used. While AV nodal reentrant tachycardias require catheters with a tip of 4mm length, an 8 mm tip electrodes will be used for atrial flutter. A pulmonary vein isolation will be performed using 4 mm irrigated tip electrodes to achieve larger and deeper lesions. The need of a tubing set and pump for saline transfusion is a disadvantage of this technique. Gold tip electrodes can alternatively be used to produce increases in lesion size. Aim of this study was to compare RF ablation catheters of exactly the same geometry with either platin-iridum or gold tip.
Methods: Gold provides an almost four-fold thermal conductivity compared with platinum-iridium. The Cerablate G flutter (Osypka AG, Rheinfelden-Herten) is a newly designed radiofrequency ablation catheter with an 8 mm gold tip. Its power delivery was compared with the Cerablate flutter of same geometry but platin-iridium tip. Therefore, in-vitro RF ablations were performed using pork meat in a 0.9% saline solution at 37°C temperature. A pulsed volume flow was generated using a pump to simulate the blood flow. Temperature controlled ablations of 60 seconds using 45, 55 and 65°C and a maximum of 70W RF power were performed.
Results: Using the Osypka HAT300smart ablator, cumulative power of 167, 474 and 672W was delivered with gold tip against 121, 227 and 310 W with platin-iridium tip. By the Stockert SmartAblate G4 ablator, 202, 546 and 1075W was delivered with gold tip against 117, 246 and 394W with platin-iridium using 45, 55 and 65°C temperature.
Conclusion: During in-vitro investigations, the gold tip electrodes allowed a in power delivery increase of 117 up to 173%. Thus, gold tips can be used to increase lesion depth and diameter without cooling equipment.
In this work a set of nonlinear coupled COM equations at interacting frequencies is derived on the basis of nonlinear electro-elasticity. The formalism is presented with the aim of describing intermodulation distortion of third-order (IMD3) and triple beat. The resulting COM equations are translated to the P-matrix formalism, where care is taken to obtain the correct frequency dependence. The scheme depends on two frequency-independent constants for an effective third-order nonlinearity. One of these two constants is negligibly small in the systems considered here. The P-matrix approach is applied to single filters and duplexers on LiTaO 3 (YXl)/42° operating in different frequency ranges. Both IMD3 and triple beat show good agreement with measurement.
A wide range catalyst screening with noble metal and oxide catalysts for a metal–air battery with an aqueous alkaline electrolyte was carried out. Suitable catalysts reduce overpotentials during the charge and discharge process, and therefore improve the round-trip efficiency of the battery. In this case, the electrodes will be used as optimized cathodes for a future lithium–air battery with an aqueous alkaline electrolyte. Oxide catalysts were synthesized via atmospheric plasma spraying. The screening showed that IrO2, RuO2, La0.6Ca0.4Co3, Mn3O4, and Co3O4 are promising bi-functional catalysts. Considering the high price for the noble metal catalysts further investigations of the oxide catalysts were carried out to analyze their electrochemical behavior at varied temperatures, molarities, and in case of La1−x Ca x CoO3 a varying calcium content. Additionally all catalysts were tested in a longterm test to proof cyclability at varied molarities. Further investigations showed that Co3O4 seems to be the most promising bi-functional catalyst of the tested oxide catalysts. Furthermore, it was shown that a calcium content of x = 0.4 in LCCO has the best performance.