Mechanical vibrations are known to affect frictional sliding and the associated stick-slip patterns causing sometimes a drastic reduction of the friction force. This issue is relevant for applications in nanotribology and to understand earthquake triggering by small dynamic perturbations. We study the dynamics of repulsive particles confined between a horizontally driven top plate and a vertica...

This paper reports the performance of a speed sensorless stand-alone Variable Speed Constant Frequency (VSCF) Doubly Fed Induction Generator (DFIG) capable of supplying all types of loads. The proposed method maintains the Total Harmonic Distortion (THD) of the machine current and the load voltage within acceptable limits. In contrast to previously proposed methods, in this paper, the stator si...

We report on frictional strengthening (healing) in granular quartz gouge as a function of time of true stationary contact. To distinguish between the slip-dependent [Ruina, 1983] and time-dependent [Dieterich, 1979] friction constitutive laws, we designed tests similar to conventional slide-hold-slide (SHS) tests except that shear load was completely removed prior to holds. We find large healin...

Pull-out tests of fibres were conducted using slow cyclic tension to evaluate the behaviour bond between cement paste and steel with different types surface roughness. Even though load amplitude increases in small steps cycles, development residual slip increment proves absence a complete at beginning loading. During steps, evolves deceleration, steady, acceleration stages. The stiffness during...

The DOE sponsored Integrated Dry NOJSO, Emissions Control System program, which is a Clean Coal Technology Ill demonstration, is being conducted by Public Service Company of Colorado. The test site is Arapahoe Generating Station Unit 4, which is a 100 MWe, down-fired utility boiler burning a low sulfur western coal. The project goal is to demonstrate 70 percent reductions in NO, and SO, emissio...

An assessment of the effects of microstructure on room temperature fatigue crack initiation and short crack propagation in a Ni-base superalloy is presented. The assessment was carried out on microstructural variants of U720Li, including as-received U720Li, U720Li-LG (large grain variant) and U720Li-LP (large intragranular coherent γ′ variant). Fatigue tests were carried out at room temperature...

OBJECTIVES Load carrying tasks are recognized as one of the primary occupational factors leading to slip and fall injuries. Nevertheless, the mechanisms associated with load carrying and walking stability remain illusive. The objective of the current study was to apply local dynamic stability measure in walking while carrying a load, and to investigate the possible adaptive gait stability chang...

The doubly-fed induction generator (DFIG) is widely used in variable speed wind energy conversion systems (WECS). This paper presents a review on various topologies, configuration, power converters and control schemes used with the operation of the DFIG. The operation of DFIG based on both slip ring and brushless arrangement has been discussed. The grid integration of DFIG and its influence on ...

This paper describes an experiment eliciting spoonerisms by using the so-called SLIP technique. The purpose of the experiment was to provide a further test of the hypothesis that self-monitoring of inner speech is a major source of lexical bias ([1; 10; 11; 14]. This is a follow-up on an earlier experiment in which subjects were explicitly prompted after each response to make a correction in ca...