52,959 research outputs found
Fermionic Quasiparticles in QCD at High Baryon Density
We study fermionic quasi-particles in QCD at very high baryon density. In the
normal quark matter phase unscreened magnetic gluon exchanges lead to non-Fermi
liquid behavior. Non-Fermi liquid effects manifest themselves in low energy
Green functions that depend on logarithms and fractional powers of energy. In
the superfluid phase there is an energy gap for fermionic excitations. Quark
mass effects can cause the energy gap to vanish. Gapless fermions in the color
flavor locked phase cause an instability towards a state with a non-zero
supercurrent.Comment: 4 pages, to appear in the proceedings of Quark Matter 2005, Budapest,
Aug 4-
Methodical Problems in Organic Farming Research
Workshop presentation with particular focus on values, transferability and praxis relevance of organic farming research. Examples from agricultural engineering lead to the conclusion, that prototype farming, goal oriented project management, participative decision making and funding, coaching of co-operation, and coaching of conflict management may enhance long term, holistic and interdisciplinary research
Forward pion production at large transverse momenta in pp collisions and beyond
The inclusive production of high-p_\perp particles (pions) in the beam
fragmentation regions of high-energy hadronic collisions is driven by the
breakup of valence constituents of the beam hadrons into their two-body
Fock-state components,and their subsequent fragmentation. We briefly discuss an
approach, that allows the consistent inclusion of intrinsic and radiatively
generated transverse momenta of initial state partons, and describe an
extension of our approach to nuclear targets.Comment: Talk given at MESON2006, Cracow, June 2006, 4 pages, 1 fi
Sustainability, overall and process efficiency of energy crops
A method to calculate efficiency of energy crop production including sun energy,
direct and indirect energy for cultivation, processing, and conversion into fuel is
demonstrated using rape and derived fuels as an example. Every production and
conversion step is a process and calculated separately. The overall efficiency
includes energy input and output of all processes. The process efficiency of rape
cultivation reaches in Finland up to 1100 %. However, the overall energy efficiency of
rape methyl ester (RME) is 1 to 2 ‰ only. The production of biogas from manure of
dairy fed by rape meal results in a process energy efficiency of 33 to 41 %, but the
overall energy efficiency of RME and biogas together is only 1.2 to 2.5 ‰. In
contrast, thermal or photovoltaic solar collectors improve overall efficiency 1 to 3
orders of magnitude compared to fuel production from rape. Competition for
cultivation area and the low photosynthetic efficiency limit the feasibility of fuel
production from energy crops. As a measure for sustainability of renewable fuel
production, the energy surplus of energy conversion from insolation to fuel per
resident and square meter is proposed
Color superconductivity: Continuity of quark and hadron matter, the role of the strange quark mass, and perturbative results
We summarize some recent results on the structure of QCD at very high baryon
density.Comment: 4 pages, to appear in the proceedings of Quark Matter 9
Technique of pneumatic pest control – analyses and a new device
Pest control in organic production of berries, potatoes and vegetables usually employs spreading technique of registered phytopharmaceutical agents. This technique may be supported or even replaced by pneumatic pest control. Pneumatic pest control means suction of pest using a vacuum device similar to a home vacuum cleaner. Up to now there is no evaluation of pneumatic pest control available from an agricultural engineering point of view. This paper concerns the following questions: Which techniques of pneumatic pest control are available and how may these techniques be improved in terms of technical and physical parameters? Based on the answers a new device design is presented
Particle algorithms for optimization on binary spaces
We discuss a unified approach to stochastic optimization of pseudo-Boolean
objective functions based on particle methods, including the cross-entropy
method and simulated annealing as special cases. We point out the need for
auxiliary sampling distributions, that is parametric families on binary spaces,
which are able to reproduce complex dependency structures, and illustrate their
usefulness in our numerical experiments. We provide numerical evidence that
particle-driven optimization algorithms based on parametric families yield
superior results on strongly multi-modal optimization problems while local
search heuristics outperform them on easier problems
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