7,255 research outputs found
Gibberella musae (Fusarium musae) sp. nov., a recently discovered species from banana is sister to F. verticillioides
Several strains of Fusarium isolated from banana were identified previously as F. verticillioides (Sacc.) Nirenberg but described as unable to produce fumonisin. Here we report biochemical and morphological evidence, as well as multilocus phylogenetic analyses based on elongation factor (EF-1a), calmodulin, b-tubulin, and the second largest subunit of RNA polymerase II (RPB2) sequences, indicating that these isolates represent a unique lineage in the Gibberella fujikuroi species complex related to but distinct from F. verticillioides. Together with previous results of molecular studies, as well as with results of metabolite analyses, crossing experiments, pathogenicity tests and morphological characterization, these new data indicate that these strains isolated from banana represent a new species, Gibberella musae Van Hove et al. sp. nov. (anamorph: Fusarium musae Van Hove et al. sp. nov.), which is described herei
Optimization of aluminium stressed skin panels in offshore applications
Since the introduction of Eurocode 9 specific design rules for the calculation of aluminium stressed skin panels are available. These design rules have been used for optimization of two extrusions: one for explosions and wind loading governing and one for explosions and floor loading governing. The optimized extrusions are fulfilling class 3 section properties leading to weight reductions up to 25% of regularly used shear panel sections. When the design would have been based on class 4 section properties even more weight reduction might have been reached. The failure mode depends on the height of the hat stiffeners. For sections using relatively high hat stiffeners failure is introduced by yielding of the heat affected zone. For these kind of cross sections the Eurocode 9 design rules and numerical calculations show very good agreement. For sections using relatively low hat stiffeners failure is introduced by global buckling. For these kind of cross sections Eurocode 9 gives rather conservative results
Optimization of aluminium stressed skin panels in offshore applications
Since the introduction of Eurocode 9 specific design rules for the calculation of aluminium stressed skin panels are available. These design rules have been used for optimization of two extrusions: one for explosions and wind loading governing and one for explosions and floor loading governing. The optimized extrusions are fulfilling class 3 section properties leading to weight reductions up to 25% of regularly used shear panel sections. When the design would have been based on class 4 section properties even more weight reduction might have been reached. The failure mode depends on the height of the hat stiffeners. For sections using relatively high hat stiffeners failure is introduced by yielding of the heat affected zone. For these kind of cross sections the Eurocode 9 design rules and numerical calculations show very good agreement. For sections using relatively low hat stiffeners failure is introduced by global buckling. For these kind of cross sections Eurocode 9 gives rather conservative results
Structural application of perforated aluminium plates in a footbridge canopy
A recently designed footbridge canopy covering a concrete bridge at the Eindhoven University of Technology campus is build up by aluminium plates containing perforations. The perforations differ in concentrations, diameter and pattern. The aluminium structure was adapted to improve global behaviour especially in relation with deformation requirements. Further experimental and numerical research was carried out to investigate the failure behaviour of perforated plates loaded by compression. It is concluded that the failure behaviour of relatively thin aluminium plates in compression is very complex, even for non-perforated plates (see [8]). Further fundamental research is needed to investigate failure modes and failure loads of the perforated plates
Experimental research on pinned connections in aluminium truss girders
Aluminium truss girders are widely used in the entertainment industry. The loads on these girders, representing systems for sound and lighting, are standardised in uniform loads and/or concentrated loads. Focusing on larger spans, standard connections, i.e. welded joints between chords and braces and mechanical fasteners between girder sections, may limit the design strength of these girders. In this publication the experimental research on pinned girder section connections, which allow for an easy assembly and disassembly of the truss girders, is described and discussed. The experiments have been carried out using two different boundary conditions as well as two different securing methods. The results show a design strength which is not limited by the shear and bearing mechanism of the pinned connection. Failure is induced by cracking of a centerpoint, which is applied for easy welding procedures
Relaxation properties of the quantum kinetics of carrier-LO-phonon interaction in quantum wells and quantum dots
The time evolution of optically excited carriers in semiconductor quantum
wells and quantum dots is analyzed for their interaction with LO-phonons. Both
the full two-time Green's function formalism and the one-time approximation
provided by the generalized Kadanoff-Baym ansatz are considered, in order to
compare their description of relaxation processes. It is shown that the
two-time quantum kinetics leads to thermalization in all the examined cases,
which is not the case for the one-time approach in the intermediate-coupling
regime, even though it provides convergence to a steady state. The
thermalization criterion used is the Kubo-Martin-Schwinger condition.Comment: 7 pages, 8 figures, accepted for publication in Phys. Rev.
Identifying predictors for energy poverty in Europe using machine learning
In this paper we identify drivers for energy poverty in Europe using machine learning. The establishment of predictors for energy poverty valid across countries is a call made by many experts, since it could provide a basis to effectively target energy-poor households with adequate policy measures. We apply a “low income, high expenditure” framework that classifies households as being at risk of energy poverty to a dataset from a survey conducted at the household-level in 11 European countries with vastly different economies, cultures, and climates. A gradient boosting classifier is successfully trained on a set of socio-economic features hypothesized as predictors for energy poverty in this diverse set of countries. The classifier's internal model is analyzed, providing novel insights into the intricacies that underlie energy poverty. We find that besides the main driver - income - floor area and household size can be confirmed as predictors. Our results suggest the presence of universal predictors that are valid across Europe, and contextual ones that are governed by local characteristics. To facilitate advanced research into energy poverty in Europe, we recommend to increase and streamline household data collection efforts, both at the country- and EU-level
Effective calculation of LEED intensities using symmetry-adapted functions
The calculation of LEED intensities in a spherical-wave representation can be substantially simplified by symmetry relations. The wave field around each atom is expanded in symmetry-adapted functions where the local point symmetry of the atomic site applies. For overlayer systems with more than one atom per unit cell symmetry-adapted functions can be used when the division of the crystal into monoatomic subplanes is replaced by division into subplanes containing all symmetrically equivalent atomic positions
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