BACKGROUND AND PURPOSE Ceramic-on-ceramic (CoC) bearings were introduced in total hip arthroplasty (THA) to reduce problems related to polyethylene wear. We compared the 9-year revision risk for cementless CoC THA and for cementless metal-on-polyethylene (MoP) THA. PATIENTS AND METHODS In this prospective, population-based study from the Danish Hip Arthroplasty Registry, we identified all the...

Prognostics and Health Management (PHM) of rotating machines is gaining importance in industry and allows increasing reliability and decreasing machines’ breakdowns. Bearings are one of the most components present in mechanical equipments and one of their most common failures. So, to assess machines’ degradations, fault prognostics of bearings is developed in this paper. The proposed method rel...

In this paper, we consider the direction of arrival (DOA) estimation issue of noncircular (NC) source in multiple-input multiple-output (MIMO) radar and propose a novel unitary nuclear norm minimization (UNNM) algorithm. In the proposed method, the noncircular properties of signals are used to double the virtual array aperture, and the real-valued data are obtained by utilizing unitary transfor...

To investigate the static characteristics of aerostatic journal bearings with porous bushing, flow model—in which compressibility lubricating gas is considered—is established based on Reynolds lubrication equation, Darcy equation for material, and continuity equation. With finite difference method, schemes non-uniform grids, relaxation virtual node numerical method governing equations compressi...

This paper reports on our research in developing a micro power generation system based on gas turbine engine and piezoelectric converter. The micro gas turbine engine consists of a micro combustor, a turbine and a centrifugal compressor. Comprehensive simulation has been implemented to optimal the component design. We have successfully demonstrated a silicon-based micro combustor, which consist...

317 SUMMARY Magnetic suspension technology has advanced to the point of being able to offer a number of advantages to a variety of applications in the rotating machinery and aerospace fields. One strong advantage of magnetic bearings over conventional bearings is the decrease in power consumption. The use of permanent magnets, along with electromagnets, is one appealing option which can further...

The influence of restriction parameters, recess depth and land-width ratios on the load capacity and stability of a Jeffcott rotor supported by single-row, six-recessed hybrid bearings with capillary compensation is studied. The finite difference method is used to solve Reynolds equation, whilst the determination of stability threshold uses the Routh-Hurwitz method. The load capacity, stability...

Active magnetic bearings offer the capability to control rotor vibration and transmitted forces through the design of adaptive controllers. These controllers can take into account the changing operating conditions and variations in the system dynamics. A Recursive Open-Loop Adaptive Control (ROLAC) algorithm was developed, which minimizes the sum of squares of the measurements in frequency doma...

Direct tracking problem of moving noncircular sources for multiple arrays is investigated in this study. Here, we propose an improved unscented particle filter (I-UPF) direct method, which combines system proportional symmetry and Markov Chain Monte Carlo (MCMC) algorithm. Noncircular can extend the dimension matrix, accuracy improved. This method uses to receive sources. Firstly, set up a mode...