1,416 research outputs found
Techno-economic comparison of renewable energy systems using multi-pole system analysis (MPSA)
The recently published method of multi-pole system analysis (MPSA) is used to techno-economically compare two wind-energy converters: offshore wind turbines and the energy ship concept. According to the method, both systems are (i) modeled, (ii) energetically and economically analyzed, (iii) technoeconomically optimized and, finally, (iv) expected uncertainties are calculated and assessed. The results of the method are used to derive the necessary cost reduction of the wind-energy converters to be economically competitive to fossil-fuel-based technologies.The authors would like to thank the Deutsche Forschungsgemeinschaft (DFG) for the financial support in the framework of the Excellence Initiative, Darmstadt Graduate School of Excellence Energy Science and Engineering (GSC 1070)
Bound states and extended states around a single vortex in the d-wave superconductors
Making use of the Bogoliubov-de Gennes equation for the d-wave
superconductors, we investigate the quasi-particle spectrum around a single
vortex. Taking , we found that there are bound states which are
localized around the vortex core, and extended states which are rather uniform,
for where is the quasi-particle energy and is the
asymptotic value of the order parameter for away from the vortex.Comment: 4 pages, 6 figure
Ford's Procedure for Combining Multiple Sets of Partially Ordered Data
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66929/2/10.1177_001316447303300104.pd
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Results for Channel Error Profiles for DECT
This letter presents the main statistical characterization
of the underlying error process obtained in the case of
the Digital European Cordless Telecommunications (DECT) radio
system. By simulation of the transmission link, error sequences
are generated for different channel parameters. Relevant statistics
are then computed for the purpose of efficient channel coding
design and evaluation
Magneto-Optical Spectrum Analyzer
We present a method for the investigation of gigahertz magnetization dynamics
of single magnetic nano elements. By combining a frequency domain approach with
a micro focus Kerr effect detection, a high sensitivity to magnetization
dynamics with submicron spatial resolution is achieved. It allows spectra of
single nanostructures to be recorded. Results on the uniform precession in soft
magnetic platelets are presented.Comment: 5 pages, 7 figure
Qualität der Arbeit: Eine Untersuchung für Ost- und Westdeutschland für die Jahre 1994 und 2009
“Quality of work” – a mainly subjective judgement of employees about their work and the corresponding conditions gained momentum over the last decades. But contrary to quantitative aspects of work and worklife, the term “quality of work” is rather hard to measure and it consists of a mixture of many single indicators related to the worklife of employees. The spectrum of these single indicators range from health considerations up to a flexible management of the work time over a month or a year. The present work contributes to the discussion about the quality of work by introducing additional single indicators into the debate. These are commuting, carreer opportunities within a firm, individual satisfaction with the work income, and a correspondence between formal qualification and the present job. The investigation distinguishes between East and West Germany as well as between age cohorts and the qualification of the interviewed persons. The results are based on the GSOEP for the years 1994 and 2009. Looking at these two years we expect some insights into possible changes in the judgement with respect to the quality of work especially for East German employees shortly after the fall of the wall and nowadays. These insights should help to draw conclusions if East and West German employees are still different in their judgements or if a process of convergence in opions occurred.
Discrimination of Helicobacter pullorum and Campylobacter lari by analysis of whole cell fatty acid extracts
Helicobacter pullorum and Campylobacter lari are rarely isolated from humans with acute enteritis. Hitherto the two species could only be identified by genotypic techniques. Gas liquid chromatography of whole cell fatty acid extracts is described as the first phenotypic method for discrimination of the two species. Cholesteryl glucoside, a characteristic feature of the genus Helicobacter, but seldom found in other bacteria, could not be detected in Helicobacter pullorum. Therefore, rapid determination of this glycolipid may serve as a discrimination marker for Helicobacter pullorum from most other Helicobacter species
Discrimination of Helicobacter pullorum and Campylobacter lari by analysis of whole cell fatty acid extracts
Helicobacter pullorum and Campylobacter lari are rarely isolated from humans with acute enteritis. Hitherto the two species could only be identified by genotypic techniques. Gas liquid chromatography of whole cell fatty acid extracts is described as the first phenotypic method for discrimination of the two species. Cholesteryl glucoside, a characteristic feature of the genus Helicobacter, but seldom found in other bacteria, could not be detected in Helicobacter pullorum. Therefore, rapid determination of this glycolipid may serve as a discrimination marker for Helicobacter pullorum from most other Helicobacter specie
Multiscale model of defective interfering particle replication for influenza A virus infection in animal cell culture
Cell culture-derived defective interfering particles (DIPs) are considered for antiviral therapy due to their ability to inhibit influenza A virus (IAV) production. DIPs contain a large internal deletion in one of their eight viral RNAs (vRNAs) rendering them replication-incompetent. However, they can propagate alongside their homologous standard virus (STV) during infection in a competition for cellular and viral resources. So far, experimental and modeling studies for IAV have focused on either the intracellular or the cell population level when investigating the interaction of STVs and DIPs. To examine these levels simultaneously, we conducted a series of experiments using highly different multiplicities of infections for STVs and DIPs to characterize virus replication in Madin-Darby Canine Kidney suspension cells. At several time points post infection, we quantified virus titers, viable cell concentration, virus-induced apoptosis using imaging flow cytometry, and intracellular levels of vRNA and viral mRNA using real-time reverse transcription qPCR. Based on the obtained data, we developed a mathematical multiscale model of STV and DIP co-infection that describes dynamics closely for all scenarios with a single set of parameters. We show that applying high DIP concentrations can shut down STV propagation completely and prevent virus-induced apoptosis. Interestingly, the three observed viral mRNAs (full-length segment 1 and 5, defective interfering segment 1) accumulated to vastly different levels suggesting the interplay between an internal regulation mechanism and a growth advantage for shorter viral RNAs. Furthermore, model simulations predict that the concentration of DIPs should be at least 10000 times higher than that of STVs to prevent the spread of IAV. Ultimately, the model presented here supports a comprehensive understanding of the interactions between STVs and DIPs during co-infection providing an ideal platform for the prediction and optimization of vaccine manufacturing as well as DIP production for therapeutic use
Direct Measurement of Quantum Confinement Effects at Metal to Quantum-Well Nanocontacts
Model metal-semiconductor nanostructure Schottky nanocontacts were made on cleaved heterostructures containing GaAs quantum wells (QWs) of varying width and were locally probed by ballistic electron emission microscopy. The local Schottky barrier was found to increase by ∼0.140 eV as the QW width was systematically decreased from 15 to 1 nm, due mostly to a large (∼0.200 eV) quantum-confinement increase to the QW conduction band. The measured barrier increase over the full 1 to 15 nm QW range was quantitatively explained when local "interface pinning" and image force lowering effects are also considered
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