Experimental Research for Dynamic Performance of Seals of the Hydraulic Steel Sluice Gate

Author(s):  
Li Kun
1965 ◽  
Vol 2 (01) ◽  
pp. 26-41
Author(s):  
W. P. A. van Lammeren

In this experimental research the effect of an eccentric shaft location on the propeller-excited vibratory forces in the propeller shaft has been investigated for a single-screw 32, 000-dwt tanker with a block coefficient of 0.769. Tests were carried out for a four and for a five-bladed propeller with conventional shaft location, as well as with a set-off of the propeller shaft of 5 and 10 percent of the propeller diameter, respectively.


2019 ◽  
Vol 13 (1) ◽  
pp. 5-10 ◽  
Author(s):  
Grzegorz Żywica ◽  
Paweł Bagiński

Abstract The article discusses the results of simulation-based and experimental research carried out on gas foil bearings. Owing to the use of a set of flexible thin foils in such bearings, they exhibit certain beneficial features that cannot be found in other types of bearings. They have nonlinear operational characteristics and allow the dissipation of excess energy, thus reducing the vibration level. Moreover, gas foil bearings can self-adapt themselves to the current operating conditions by changing the shape of the lubrication gap. Therefore, they can be used to improve the dynamic performance of rotors, in particular, those operating at very high rotational speeds. This article explains the mechanisms for changes of stiffness and vibration damping in compliant components of a foil bearing. The results of the analysis of the bearing’s subassemblies using advanced numerical models are presented. They are followed by conclusions that were drawn not only from these results but also from the results of the experimental research. It has been proven that the rotor supported on carefully designed foil bearings is capable of maintaining a low vibration level, even if it operates at a high rotational speed.


2009 ◽  
Vol 40 (2) ◽  
pp. 55-65 ◽  
Author(s):  
Thomas F. Pettigrew

This paper reviews the evidence for a secondary transfer effect of intergroup contact. Following a contact’s typical primary reduction in prejudice toward the outgroup involved in the contact, this effect involves a further, secondary reduction in prejudice toward noninvolved outgroups. Employing longitudinal German probability samples, we found that significant secondary transfer effects of intergroup contact exist, but they were limited to specific outgroups that are similar to the contacted outgroup in perceived stereotypes, status or stigma. Since the contact-prejudice link is bidirectional, the effect is inflated when prior prejudice reducing contact is not controlled. The strongest evidence derives from experimental research. Both cognitive (dissonance) and affective (evaluative conditioning) explanations for the effect are offered.


1983 ◽  
Vol 28 (10) ◽  
pp. 805-805
Author(s):  
Roger E. Kirk

Sign in / Sign up

Export Citation Format

Share Document