47,100 research outputs found
Investigation of squeeze-film dampers
Squeeze film dampers are a means of curing instabilities in rotating shaft assemblies. Their efficiency depends very much on the condition of the oil, which in turn depends on inlet and outlet arrangements, on damper geometry and on the flexibility of the rotor and surrounding structure. Rig investigations in which structural flexibility is included experimentally are discussed. Comparisons are made between measured and predicted results
A structure for maturing intelligent tutoring system student models
A special structure is examined for evolving a detached model of the user of an intelligent tutoring system. Tutoring is used in the context of education and training devices. A detached approach to populating the student model data structure is examined in the context of the need for time dependent reasoning about what the student knows about a particular concept in the domain of interest. This approach, to generating a data structure for the student model, allows an inference engine separate from the tutoring strategy determination to be used. This methodology has advantages in environments requiring real-time operation
Tribo-corrosion of steel in artificial saliva
Stainless steel is widely used as dental implant. However, there has been little work on the micro-abrasion of such materials in laboratory simulated oral environments, where abrasion, sliding wear can interact simultaneously. In this study, the effects of applied load, and exposure time were evaluated for a 316 stainless steel in a laboratory simulated artificial saliva. Polarization curves showed an enhancement of corrosion current density with increases in applied load. Wear maps were produced showing low wear safety regimes at intermediate loads and exposure times. Possible reasons for such trends are interpreted in terms of the ability of the passive film in providing resistance against third body particle impact and the concentration of particles in the contact at higher loads
Fearless: Christine Serwan and Sam Holmes
This week, we’re recognising the fearless work that Christine Serwan ’13 and Sam Holmes ’13 will be doing over the next two years during with the Peace Corps. [excerpt
Modelling Interdependent Cascading Failures in Real World Complex Networks using a Functional Dependency Model
Infrastructure systems are becoming increasingly complex and interdependent. As a result our ability to predict the
likelihood of large-scale failure of these systems has significantly diminished and the consequence of this is that we
now have a greatly increased risk of devastating impacts to society.
Traditionally these systems have been analysed using physically-based models. However, this approach can only
provide information for a specific network and is limited by the number of scenarios that can be tested. In an attempt
to overcome this shortcoming, many studies have used network graph theory to provide an alternative analysis
approach. This approach has tended to consider infrastructure systems in isolation, but has recently considered
the analysis of interdependent networks through combination with percolation theory. However, these studies have
focused on the analysis of synthetic networks and tend to only consider the topology of the system.
In this paper we develop a new analysis approach, based upon network theory, but accounting for the hierarchical
structure and functional dependency observed in real world infrastructure networks. We apply this method to two
real world networks, to show that it can be used to quantify the impact that failures within an electricity network have
upon a dependent water network
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