48 documents found, page 1 of 5
The impact of chronic stress on the rat brain lipidome
Oliveira, Tiago Gil; Chan, Robin B.; Bravo, F. V.; Miranda, A. S.; Silva, R. R.; Zhou, B.; Marques, Fernanda; Pinto, V.; Cerqueira, João JoséChronic stress is a major risk factor for several human disorders that affect modern societies. The brain is a key target of chronic stress. In fact, there is growing evidence indicating that exposure to stress affects learning and memory, decision making and emotional responses, and may even predispose for pathological processes, such as Alzheimer's disease and depression. Lipids are a major constituent of the...
The role of lubricant feeding conditions on the performance improvement and fri...
Brito, F. P.; Miranda, A. S.; Claro, José Carlos Pimenta; Teixeira, J. Carlos; Costa, Lucrécio; Fillon, M.Most conventional hydrodynamic journal bearing performance tools can not suitably assess the effect of lubricant feeding conditions on bearing performance, even though these conditions are known to affect important performance parameters such as eccentricity and powerloss. A thermohydrodynamic analysis suitable to deal with realistic feeding conditions has been proposed. Special attention was given to the treat...
Friction and wear properties of functionally graded aluminum matrix composites
Gomes, J. R.; Rocha, L. A.; Crnkovic, S. J. [UNESP]; Silva, R. F.; Miranda, A. S.Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-27T11:20:40Z No. of bitstreams: 0; Made available in DSpace on 2014-05-27T11:20:40Z (GMT). No. of bitstreams: 0 Previous issue date: 2003-06-25; Aluminum matrix composites are currently considered as promising materials for tribological applications in the automotive, aircraft and aerospace industries due to their great advanta...
Thermohydrodynamic modelling of journal bearings under varying load angle and n...
Brito, F. P.; Miranda, A. S.; Claro, José Carlos Pimenta; Fillon, M.; Teixeira, J. Carlos; Costa, LilianaThe performance of hydrodynamic journal bearings is affected by the conditions under which the lubricant is fed to the bearing gap. Axial grooves are often used and, depending on their location relatively to the load line, they might substantially interfere with the hydrodynamic pressure generation and the thermal behaviour of the bearing. However, many of the existing tools for predicting bearing performance a...
The role of lubricant feeding conditions on the performance improvement and fri...
Brito, F. P.; Miranda, A. S.; Claro, José Carlos Pimenta; Teixeira, J. Carlos; Costa, Lucrécio; Fillon, M.The performance of hydrodynamic journal bearings is significantly affected by the conditions under which the lubricant is fed to the bearing. However, many conventional analyses are not prepared to suitably incorporate these parameters and their effect on bearing performance, due to the over-simplified way they treat them. A thermohydrodynamic analysis suitable for conveniently deal with lubricant feeding condi...
The work on hydrodynamic journal bearings carried out at Minho University in th...
Claro, José Carlos Pimenta; Miranda, A. S.; Costa, Lucrécio; Brito, F. P.; Fillon, M.The hydrodynamic journal bearing is still one of the most geometrically simple mechanical components, yet highly reliable and efficient and, above all, unique in what concerns to heavy duty – high load, high speed – support of rotating shafts. Analytical studies, not only to understand the physical basis of its performance, but also to develop practical tools for an expedite design, as well as to assure its rel...
Analysis of friction in the ejection of thermoplastic mouldings
Correia, Mário Simões; Miranda, A. S.; Oliveira, Marta Cristina; Capela, Carlos Alexandre; Pouzada, A. S.The ejection force of injection-moulded thermoplastics depends on the contact conditions at the moment of ejection. Replication of the polymer part surface occurs onto the mould surface during injection of the melt. Ejection takes place in a very short time, hence the static coefficient of friction must be considered for modelling the ejection process. To understand the contribution of the mechanisms involved i...
Experimental Comparison of the Performance of a Journal Bearing with a Single a...
Brito, F. P.; Miranda, A. S.; Claro, José Carlos Pimenta; Fillon, M.It is often assumed that a twin groove arrangement will provide a more effective lubrication and a cooler operation than a single groove one, but little evidence has been found in support of this claim. Furthermore, there are no experimental works, to the authors’ knowledge, that compare the performance of single and twin axial groove bearings with the same geometry. An experimental assessment of a journal bear...
Experimental comparison of the performance of a journal bearing with a single a...
Brito, F. P.; Miranda, A. S.; Claro, José Carlos Pimenta; Fillon, M.It is often assumed that a journal bearing will operate more effectively with a twin groove arrangement than a single groove one, but little evidence has been presented in support of this. An experimental assessment of a journal bearing with either one or two axial grooves located perpendicularly to the load line was performed. It was found that under heavy loaded operation the twin groove configuration might a...
On the occurrence of negative groove flow rate in twin groove hydrodynamic jour...
Brito, F. P.; Miranda, A. S.; Claro, José Carlos Pimenta; Teixeira, J. Carlos; Costa, Lucrécio; Fillon, M.This paper describes the phenomenon of negative flow rate (hot oil reflux) occurring in one of the grooves of twin axial groove hydrodynamic journal bearings. This rarely described phenomenon, which can occur under severe operating conditions, increases the risk of bearing seizure. Existing codes for predicting bearing behaviour do not seem to be suitably incorporating this phenomenon into the analysis. The pre...