87,553 research outputs found
Wind loads analysis at the anchorages of the Talavera de la Reina cable stayed bridge
No full textThis paper describes wind tunnel tests performed on wind tunnel models of the Talavera de la Reina cable stayed bridge. The work describes the aeroelastic model construction and it is focused on the evaluation and analysis of the mean and peak wind loads at the tower foundation and the cable anchorages since these data can be very useful by the bridge manufacturer as a support for the bridge design. The work is part of a complete wind tunnel study carried out to analyze the aeroelastic stability of the bridge
Ruolo dei recettori tachichininici NK2 nella contrazione della muscolatura liscia circolare dell'ileo di cavallo
No full textSuitability of the old fowl rectal caecum preparation for investigating the selectivity of β-adrenergic drugs
No full textWe tested alpha- and beta-adrenergic drugs on isolated strips of fowl rectal caecum from 14- to 16-week-old Warren hens. Basal tone and spontaneous motility were dose-dependently reduced by isoprenaline and all the selective beta-agonists tested (except xamoterol) with the following order of potency: isoprenaline=fenoterol=procaterol=clenbuterol>dobutamine> SR58611A. The results indicate that this tissue preparation consists almost entirely of beta2-adrenoceptors. This preparation may, therefore, be considered a suitable assay for discriminating beta1- from beta2-agonists according to their selectivity
Experimental Assessment of Mega-Yacht Aerodynamic Performances and Characteristics
No full textIn this paper experimental methodologies developed at Politecnico di Milano Wind Tunnel in ordere to assess mega-yacht aerodynamics in terms of aerodynamic loads, comfort analysis, pollutants dilution and re-ingestion analysis using wind tunnel tests are described
A large-scale wind turbine model installed on a floating structure:experimental validation of the numerical design
No full textIn the field of floating wind energy, large-scale wind turbine models deployed in natural environments represent a key link between small-scale laboratory tests and full-scale prototypes. While implying smaller cost, design and installation effort than a full-scale prototype, large-scale models are technologically very similar to prototypes, can be tested in natural sea and wind conditions, and reduce by a consistent amount the dimensional scaling issues arising in small-scale experiments. In this framework the presented work report the aerodynamic and control system assessment of a 1:15 model of the DTU 10 MW wind turbine installed on a multipurpose-platform model for fish farming and energy production. The model has operated for 6 months in a natural laboratory and has been exposed to fully natural and uncontrolled environmental conditions. Assessment is performed in terms of rotor thrust force and power controller parameters such as rotor speed, blade pitch and rotor power as a function of incoming wind speed
Adrenergic regulation of vascular smooth muscle tone in calf digital artery
No full textRadioligand binding studies and functional assays on isolated smooth muscle
preparations were performed in order to obtain a biochemical and functional
characterization of the b-adrenoceptor (b-AR) subtypes involved in regulation
of the smooth muscle relaxation of the calf’s common digital artery. The results
indicate that the common digital artery possesses two b-AR populations (40%
b1 and 60% b2) and the b2-subtype appears to predominate as far as function is
concerned. Only the b2-AR agonists clenbuterol and fenoterol caused doserelated
relaxant effects, antagonized by propranolol, when tested in preparations
precontracted both with PGF2a (1.4 · 10)5
M) and noradrenaline
(1.2 · 10)6
M). In noradrenaline precontracted preparations the b1-AR
selective agonists dobutamine and xamoterol caused vasodilation which was
not antagonized by (±)propranolol. While the functional relaxant effects of
dobutamine may be attributed to its potent competitive a-AR blocking activity,
further investigations are required to explain the effect of xamoterol. The
vasodilator effect of (±)isoproterenol was irregular. The recorded contractile
effects, mainly at dosages greater than 10)6
M, suggest the loss of drug
selectivity for b-AR and a-AR activation. Indirect evidence indicates that the aadrenoceptor
(a-AR) population in this tissue which produces a strong
contraction is functionally dominant over the b-AR, suggesting limited
therapeutic benefit for b-AR drugs to control blood flow disorders in the calf’s
distal limb
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