118 research outputs found

    Business plan tool for small biogas plants

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    An on-line advisor for sizing and economic analysis of anaerobic digestion plants

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    A web-based service was deployed to appropriately size bio-gas plant capacity and perform its economic viability and return on investment based on biomass availability.  The tool is based on accepted biogas plant engineering design practice, incorporating the effects of incentives resulting from energy policies for member nations of the European Union participating in the Bioenergy Farm IEE and EU funded project.  The service provides a comprehensive database that allows consultants and farmers to analyze anaerobic digestion systems at different levels of granularity.  It also included multilingual support.  An adoption program was conducted to increase awareness on the availability of the service and ensure appropriate use and interpretation of its results.  Since its deployment, the tool has been frequently used by consultants and farmers.  The advisor was used to conduct over 3000 sizing and analysis of biogas production plants and completely fulfill all project targets.   Keywords: Bioenergy, feasibility, viability, subsidy, web application, fre

    Is there an Aoki phase in quenched QCD?

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    We argue that quenched QCD has non-trivial phase structure for negative quark mass, including the possibility of a parity-flavor breaking Aoki phase. This has implications for simulations with domain-wall or overlap fermions.Comment: Parallel talk presented at Lattice2004(spectrum), Fermilab, June 21-26, 200

    From attosecond to zeptosecond coherent control of free-electron wave functions using semi-infinite light fields

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    Light-electron interaction in empty space is the seminal ingredient for free-electron lasers and also for controlling electron beams to dynamically investigate materials and molecules. Pushing the coherent control of free electrons by light to unexplored timescales, below the attosecond, would enable unprecedented applications in light-assisted electron quantum circuits and diagnostics at extremely small timescales, such as those governing intramolecular electronic motion and nuclear phenomena. We experimentally demonstrate attosecond coherent manipulation of the electron wave function in a transmission electron microscope, and show that it can be pushed down to the zeptosecond regime with existing technology. We make a relativistic pulsed electron beam interact in free space with an appropriately synthesized semi-infinite light field generated by two femtosecond laser pulses reflected at the surface of a mirror and delayed by fractions of the optical cycle. The amplitude and phase of the resulting coherent oscillations of the electron states in energymomentum space are mapped via momentum-resolved ultrafast electron energy-loss spectroscopy. The experimental results are in full agreement with our theoretical framework for light-electron interaction, which predicts access to the zeptosecond timescale by combining semi-infinite X-ray fields with free electrons.Comment: 22 pages, 6 figure

    Laser-Induced Skyrmion Writing and Erasing in an Ultrafast Cryo-Lorentz Transmission Electron Microscopy

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    We demonstrate that light-induced heat pulses of different duration and energy can write skyrmions in a broad range of temperatures and magnetic field in FeGe. Using a combination of camera-rate and pump-probe cryo-Lorentz Transmission Electron Microscopy, we directly resolve the spatio-temporal evolution of the magnetization ensuing optical excitation. The skyrmion lattice was found to maintain its structural properties during the laser-induced demagnetization, and its recovery to the initial state happened in the sub-{\mu}s to {\mu}s range, depending on the cooling rate of the system
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