Instability of an intershaft squeeze film damper in a two-spool rotor dynamics simulator

An instability associated with an intershaft squeeze film damper is described. The squeeze film is located between the intershaft bearing outer race and the low-speed shaft of a five-bearing, two-spool test rig. The instability is dominated by response of the third system mode to destabilizing excitation of the type described by Hibner, et al. Installing a spring cage in place of the intershaft damper removes the instability and produces satisfactory performance throughout the operating range

Surveyor lunar touchdown stability study Final report, Jul. 1965 - Jul. 1966

Dynamic analysis and computer simulation of Surveyor lunar landing stabilit

Elastic constants of 3-, 4- and 6-connected chiral and anti-chiral honeycombs subject to uniaxial in-plane loading

Finite Element models are developed for the in-plane linear elastic constants of a family of honeycombs comprising arrays of cylinders connected by ligaments. Honeycombs having cylinders with 3, 4 and 6 ligaments attached to them are considered, with two possible configurations explored for each of the 3- (trichiral and anti-trichiral) and 4- (tetrachiral and anti-tetrachiral) connected systems. Honeycombs for each configuration have been manufactured using rapid prototyping and subsequently characterised for mechanical properties through in-plane uniaxial loading to verify the models. An interesting consequence of the family of 'chiral' honeycombs presented here is the ability to produce negative Poisson's ratio (auxetic) response. The deformation mechanisms responsible for auxetic functionality in such honeycombs are discussed

A critical realist analysis of consent to surgery for children, human nature and dialectic: the pulse of freedom

Consent can only be voluntary, freely given and uncoerced. Can this legal adult standard also apply to children? High-risk surgery is seldom a wanted choice, but compared with the dangers of the untreated problem, surgery can become the least unwanted option. Critical realism helps to reveal explicit and hidden levels of informed and voluntary consent at empirical, actual and real levels, on the four planes of social being and through the four-stage dialectic. Instead of starting with the rational-legal adult patient standard of consent, and assessing how young children fail this, understanding of consent could start at the other end of life. What does innate physical-social-moral-intuitive human nature in the emotional embodied person tell us about the meaning and purpose of consent/refusal for self-preservation, for avoiding suffering and promoting wellbeing? This discussion paper considers examples of life-giving treatment for children, and ethical dilemmas including one of conjoined twins, when only one child could survive separation

Children's consent and the zone of parental discretion

This paper briefly reviews highlights from decades of debates in medicine, law, bioethics, psychology and social research about children’s and parents’ views and consent to medical treatment and research. There appears to have been a rise and later a fall in respect for children’s views, illustrated among many examples by a recent book on the zone of parental discretion, which is reviewed. A return to greater respect for children’s views and consent is advocated