34,345 research outputs found
Comparing low rate copper formulations against Phythophthora infestans in potatoes
Between Dutch organic growers the late blight problems lead to discussions in which a temporary registration of copper products is also suggested. Some growers do not want any pesticides at all, while others see that biological potatoes from abroad are sold in the super markets in years when Dutch organic potatoes are scarce. Those potatoes come from countries, where copper products are allowed. They speak about competition falsification. In the research program to stimulate organic production the choice is made to also investigate the efficacy of copper and other products that are allowed in surrounding countries in organic farming. In the experiment of 2008 6 different copper containing products are tested
Control of Phytophthora infestans with low copper amounts in potatoes in 2010
Between Dutch organic growers the late blight problems led to discussions in which a temporary registration of copper products is also suggested. In the research program to stimulate organic production the choice was made also to investigate the efficacy of copper and other products that are allowed in neighbouring countries in organic farming. In the experiment of 2008 different copper containing products were tested. In 2009 this was repeated with the same products, but also other doses and combinations. In 2010 the most important objective of the experiment was to investigate the possibilities of a maximum of 300 gram copper per hectare, divided in different parts, in combination with a decision support system. 300 gram copper was based on the amount different crops need in a six year organic rotation. Except a standard copper product also a copper product used in organic farming in the Netherlands as a leaf fertilizer was used and some products financed by the industry
Extension-twist coupled laminates for aero-elastic compliant blade design
A definite list of laminate configurations with extension-twisting (and shearing-bending) coupling is derived for up to 21 plies of identical thickness. The list comprises individual stacking sequences, containing standard angle-ply and cross-ply sub-sequences; combinations which are contrary to the previously assumed form for this class of laminate. The list also contains dimensionless parameters from which the extensional, coupling and bending stiffness terms are readily calculated for any fiber/matrix system. Lamination parameters are shown graphically to illustrate the extent of the design space with up to 21 plies. A special sub-group from this class of coupled laminate is identified that can be manufactured flat under a standard elevated temperature curing process; this sub-group possesses hygro-thermally curvature-stable behavior. Finally, bounds on the compression buckling strength are assessed using a closed form solution for all the laminate groups presented
Low rate copper products to control Phytophthora infestans in potatoes in 2009
Between Dutch organic growers the late blight problems lead to discussions in which a temporary registration of copper products is also suggested. Some growers do not want any pesticides at all, while others see that biological potatoes from abroad are sold in the super markets in years when Dutch organic potatoes are scarce. Those potatoes come from countries, where copper products are allowed. They speak about competition falsification. In the research program to stimulate organic production the choice is made to also investigate the efficacy of copper and other products that are allowed in surrounding countries in organic farming. In the experiment of 2008 different copper containing products are tested. In 2009 this was repeated with the same products, but also other doses and combination
Wage moderating effects of corporatism: Decentralized versus centralized wage setting in a union, firm, government context
Trade Unions;Corporatism;labour economics
Inefficiency of automatically linking unemployment benefits to private sector wage rates
Labour Economics
Gluon Chain Model of the Confining Force
We develop a picture of the QCD string as a chain of constituent gluons,
bound by attractive nearest-neighbor forces which may be treated
perturbatively. This picture accounts for both Casimir scaling at large N, and
the asymptotic center dependence of the static quark potential. We discuss the
relevance, to the gluon-chain picture, of recent three-loop results for the
static quark potential. A variational framework is presented for computing the
minimal energy and wavefunction of a long gluon chain, which enables us to
derive both the logarithmic broadening of the QCD flux tube (``roughening''),
and the existence of a Luscher -c/R term in the potential.Comment: 25 pages, 5 figures, latex2
Natural frequency prediction for laminated rectangular plates with extension-bending or extension-twisting and shearing-bending coupling
This article presents closed form natural frequency solutions for two classes of
mechanically coupled laminate with: extension-bending or; extension-twisting and shearingbending. Details on the derivation of these two laminate classes are given; all of which
contain combinations of standard ply angles, e.g. +45, -45, 0 and 90°. Upper and lower
bounds on the non-dimensional natural frequencies are shown graphically for each class of
laminate over a range of aspect ratios. Finally, differences are highlighted between these
bounds and others obtained by the simplifying assumption that the two laminate classes
contain only cross plies or angle plies, respectively
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