226 research outputs found
Perlo winter wheat
No full text Perlo is a winter wheat (Triticum aestivum L. em. Thell.) with breadmaking quality, high grain yield, and adequate lodging resistance. It is moderately resistant to powdery mildew (caused by Erysiphe graminis Merat D.C. ex f. sp. tritici Marchal) and septoria leaf and glume blotch (caused by Septoria nodorum Berk.). Perlo is suited for production in areas of Eastern Canada where winter survival is not a problem. Key words: Wheat (winter), cultivar description </jats:p
Influence of the excavation rate on the mechanical response of deep tunnel fronts in cohesive soils
No full textIn conventional tunnelling, the mechanical response of the tunnel front is a main concern and depends on both the geometry (tunnel diameter and cover) and soil mechanical properties. Moreover, in case of excavations in soils characterized by a low value of permeability, even the time factor plays an important role: in case of particularly problematic soils, the displacements of the front are expected to progressively increase with time and tunnel fronts stable under short term conditions potentially either develop unacceptable displacements or become unstable under long term conditions. In this paper, the mechanical response of deep tunnel fronts excavated in a homogeneous cohesive soil stratum are analysed by both performing experimental 1g small scale model tests and non-linear 3D FEM analyses. The numerical results are obtained by assuming the material to be isotropic, homogeneous and characterized by an elastic-perfectly plastic constitutive relationship. The results are presented in terms of the tunnel front characteristic curve, defined in analogy with the well-known characteristic curve for the tunnel cavity and by employing a suitable non-dimensional variable depending on the excavation time, the soil hydraulic/mechanical properties and the tunnel geometry. Finally, the authors introduce a rapid procedure allowing the front displacements estimation without performing ad hoc numerical analyses
Influence of the fibreglass reinforcement stiffness on the mechanical response of deep tunnel fronts in cohesive soils under undrained conditions
No full textThe fronts of tunnels excavated under particularly difficult ground conditions are commonly reinforced by inserting fibreglass pipes. This technique is particularly popular since it is very simple to adapt the reinforcement number/length according to the nature of soils encountered. In this paper, the authors illustrate the results of a 3D FEM numerical campaign aimed at analysing the influence of the reinforcements on the system response, con-veniently summarized by employing a suitably normalized front characteristic curve. The numerical analyses were performed by assuming the material to be isotropic, homogeneous and characterized by an elastic-perfectly plastic constitutive relationship. Only undrained conditions are taken into account: the failure locus is defined according to the Tresca criterion and the flow rule is assumed to be associated. The numerical results show that the effectiveness of the inclusions is not related to the absolute value of the inclusion stiffness but to the value of a suitably defined non-dimensional variable. By employing this non-dimensional variable the authors show that it is possible to tailor the reinforcement stiffness according to the nature of the soil encountered
NMR-investigation of the mechanism of silver mercaptide thermolysis in amorphous polystyrene
No full textNANOSTRUCTURED MATERIAL: IN SITU SYNTESIS OF POLYMER-EMBEDDED METAL AND SULFIDE CLUSTERS BY THERMOLYSIS OF ALKANETHIOLATES/POLYMER BLENDS
No full textAN UNIVERSAL METHOD FOR THE SYNTESIS OF METAL AND METAL SULFIDE CLUSTERS EMBEDDED IN POLYMER MATRICES
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