1,721,018 research outputs found
Fatigue strength of a fork-pin equivalent coupling in terms of the local strain energy density
No full textThe fork-pin coupling of the front suspension of a motorbike is very important for the reliability and the safety of the entire vehicle. One of the more important causes of failure of the component is fatigue under fully reversed bending load. In this work, the fatigue behaviour of fork-pin equivalent couplings made of 39NiCrMo3 steel is analysed by means of simplified specimens obtained by the interference of a cylindrical pin in a hollow cylinder reproducing the same static stresses present on the contact surfaces of the real component. The contact of the two bodies is modelled by means of Ansys (R) 9.0 and the stress field due to the interference is analysed and compared with that obtained by a strain gauge located on the external surface of the equivalent hub during the press-fit operation. By means of the same three-dimensional model, the local strain energy density (SED) averaged in a control volume, defined under mode I loading and surrounding the critical zone of the pin, is evaluated to summarize all fatigue strength data. The data, expressed in terms of the local energy, fall in the same scatter band with some other new data from plain and V-notched specimens made of the same material subjected to tension loading. Altogether about 60 new fatigue results are now available and presented in the paper
Fatigue strength of a fork-pin equivalent coupling in terms of the local Strain Energy Density
No full textThe fork-pin coupling of the front suspension of a motorbike is very important for the reliability and the safety of the entire vehicle. One of the more important causes of failure of the component is fatigue under fully reversed bending load. In this work, the fatigue behaviour of fork-pin equivalent couplings made of 39NiCrMo3 steel is analysed by means of simplified specimens obtained by the interference of a cylindrical pin in a hollow cylinder reproducing the same static stresses present on the contact surfaces of the real component. The contact of the two bodies is modelled by means of Ansys 9.0 and the stress field due to the interference is analysed and compared with that obtained by a strain gauge located on the external surface of the bush during the press-fit operation. By means of the same three-dimensional model, the local Strain Energy Density (SED) averaged in a control volume, defined under mode I loading and surrounding the critical zone of the pin, is evaluated to summarise all fatigue strength data. The data, expressed in terms of local energy, fall in the same scatter band with some other new data from plain and V-notched specimens made of the same material subjected to tension loading. Altogether about sixty new fatigue results are now available and presented in the paper
GABAergic Input Affects Intracellular Calcium Levels in Developing Granule Cells of Adult Rat Hippocampus.
Full text linkIn the dentate gyrus (DG) of the mammalian hippocampus, granule neurons are generated from neural stem cells (NSCs) throughout the life span and are integrated into the hippocampal network. Adult DG neurogenesis is regulated by multiple intrinsic and extrinsic factors that control NSC proliferation, maintenance, and differentiation into mature neurons. γ-Aminobutyric acid (GABA), released by local interneurons, regulates the development of neurons born in adulthood by activating extrasynaptic and synaptic GABAA receptors. In the present work, patch-clamp and calcium imaging techniques were used to record very immature granule cells of adult rat dentate gyrus for investigating the actual role of GABAA receptor activation in intracellular calcium level regulation at an early stage of maturation. Our findings highlight a novel molecular and electrophysiological mechanism, involving calcium-activated potassium channels (BK) and T-type voltage-dependent calcium channels, through which GABA fine-tunes intracellular calcium homeostasis in rat adult-born granule neurons early during their maturation. This mechanism might be instrumental in promoting newborn cell survival
Trauma fisico ed esordio tardivo dell'anoressia nervosa.
No full textTrauma fisico ed esordio tardivo dell'anoressia nervosa
Fatigue tests on a compression fork-pin coupling of a front motorbike suspension under fully reversed bending load
No full textUn caso di anoressia nervosa con singolare pattern alimentare.
No full textRiportando il caso di una ragazza di 24 anni, si discute su come la comorbilità con un disturbo di personalità possa avere un effetto patoplastico sul Disturbo del Comportamento Alimentar
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