Crystal distribution in articular cartilage of femoral heads resected at hip arthroplasty for fracture of the femoral neck was examined in 10 patients (77-91 years) by computerised image analysis of electron micrographs. Crystal content of the zenith did not differ from that of the infrafoveal region of the femoral head in the superficial 0.5 mm of the cartilage. Crystal area density (percentag...

Aluminum matrix composites reinforced with Al2O3 and SiC particles (5 Vol%) were produced using the hot powder extrusion method. Extrusion temperature and extrusion reduction in area were chosen in the range of 500 to 600°C and 90 to 95%, respectively. The physical and mechanical properties of the extruded composites such as density, tensile strength, elongation and microhardness were evaluated...

Aluminum matrix composites reinforced with Al2O3 and SiC particles (5 Vol%) were produced using the hot powder extrusion method. Extrusion temperature and extrusion reduction in area were chosen in the range of 500 to 600°C and 90 to 95%, respectively. The physical and mechanical properties of the extruded composites such as density, tensile strength, elongation and microhardness were evaluated...

Copper matrix composite reinforced by 1wt.% TiB2 particles was prepared using in situ reaction of Cu-1.4wt.% Ti and Cu-0.7wt.% B by rapid solidification and subsequent heat treatment for 1-20 hrs at 900ºC. High-resolution transmission electron microscopy (HRTEM) characterization showed that primary TiB2 particles were formed in liquid copper. Heat treatment of as-solidified samples led to ...

Control theory has long provided a rich source of motivation for developments in matrix theory. Accordingly, we discuss some open problems in matrix theory arising from theoretical and practical issues in linear systems theory and feedback control. The problems discussed include robust stability, matrix exponent& induced norms, stabilizability and pole assignability, and nonstandard matrix equa...

A wind farm is a collection of wind turbines built in an area to provide electricity. Wind power is a renewable energy resource and an alternative to non-renewable fossil fuels. In this paper impact of wind farms in power system reliability is investigate and a new procedure for reliability assessment of wind farms in HL1 level is proposed. In proposed procedure, application of Fuzzy – Markov f...

Mesangial cells play an important role in maintaining a structure and function of the glomerulus and in the pathogenesis of glomerular diseases. Recently, we discovered a new mesangium-predominant gene termed "megsin." Megsin is a novel protein that belongs to the serine protease inhibitor (serpin) superfamily. To elucidate the pathophysiologic role of megsin in the kidney, the expression and l...

copper matrix composite reinforced by 1wt.% tib2 particles was prepared using in situ reaction of cu-1.4wt.% ti and cu-0.7wt.% b by rapid solidification and subsequent heat treatment for 1-20 hrs at 900ºc. high-resolution transmission electron microscopy (hrtem) characterization showed that primary tib2 particles were formed in liquid copper. heat treatment of as-solidified samples led to the f...

analysis of time series data can involve the inversion of large covariance matrices. for theclass of arma (p, q) processes there are no exact explicit expressions for these inverses, except for thema (1) process. in practice, the sample covariance matrix can be very large and inversion can becomputationally time consuming and so approximate explicit expressions for the inverse are desirable.thi...