118 research outputs found
An on-line advisor for sizing and economic analysis of anaerobic digestion plants
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?
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
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
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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