1,721,025 research outputs found
Quale partecipazione è pubblica?
No full textPartecipazione dal basso o partecipazione dall'alto promossa da pubbliche istituzioni sensibili? Volge al termine una stagione che ha visto il ruolo trainante di alcune istituzioni pubbliche. Quella attuale è in prevalenza una stagione di reti e movimenti dal basso, in cui si ondeggia tra particolarismo e coesione sociale. Si aprono nuove possibilità, ma anche nuovi interrogativi
Carbamate Synthesis from Amines and Dimethyl Carbonate under Ytterbium Triflate Catalysis
No full textCarbamate synthesis from amines and dimethyl carbonate under ytterbium triflate catalysis.
No full textA facile synthesis of carbamates from amines and dimethyl carbonate has been achieved using ytterbium triflate as catalys
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Ytterbium Triflate Promoted Coupling Reaction Between Aryl Alkynes and Aldehydes
No full textA simple and efficient solvent-free coupling reaction affording regioselectively trans-α,β-enones from aryl alkynes and aldehydes catalysed by Yb(OTf)3 hydrate is described
Design of deep excavations in fine-grained soils accounting for changes in pore water pressures
No full textThe behaviour of a deep excavation is especially influenced by the strength and deformability of the soil located in front of the retaining walls, below the bottom of the excavation. In fine-grained, low-permeability soils, it is usually assumed that the excavation is carried out in undrained conditions, resulting in a significant decrease of the pore water pressures. This effect is beneficial, because the effective stresses are kept nearly at their initial values, but has a transient nature: depending on the problem layout, on the soil permeability and on the rapidity of the construction process, the negative excess pore pressure may dissipate in a time span comparable to that needed to complete the construction. For design purposes, it is essential to consider reasonable values of the pore water pressures, to ensure a satisfactory performance of the construction avoiding at the same time excessive conservatism. This paper illustrates the results of a parametric study, in which finite-element analyses were carried out to evaluate the excess pore water pressures induced by excava-tions and to asses the effects of their variation with time. The mechanical behaviour of the clayey soils was described using a constitutive model based on hardening plasticity, that is reasonably accurate in simulating the generation of excess pore water pressures in undrained conditions. The results of this study are used to provide practical indications about the values of excess pore water pressures to be considered for design
- …
