We read the article “Anatomical ACL reconstruction with double bundle: first 40 cases” by Zekcer A. et al [Rev Bras Ortop 2011;46(3): 262-5] with great interest and would like to make some comments on what was reported in that paper. The authors drilled an anteromedial femoral tunnel with the knee flexed at 90°. At this degree of flexion, the tunnel is significantly shorter than it is at flexio...

Scientific maintenance methodologies are specially needed to enhance system reliability and safety, reduce maintenance manpower, spares, and repair costs, eliminate scheduled inspections, and maximize lead time for maintenance and parts procurement. This paper systematically presents a comprehensive methodology and framework for aggressive inspection and condition based predictive maintenance o...

Let K be a knot with an unknotting tunnel γ and suppose that K is not a 2-bridge knot. There is an invariant ρ = p/q ∈ Q/2Z, p odd, defined for the pair (K, γ). The invariant ρ has interesting geometric properties: It is often straightforward to calculate; e. g. for K a torus knot and γ an annulus-spanning arc, ρ(K, γ) = 1. Although ρ is defined abstractly, it is naturally revealed when K ∪ γ i...

the main rock mass classification systems make use of similar rock mass parameters. due to lack of comprehensive estimation systems, determining the real specifications of jointed rocks faces some difficulties. a vast number of parameters with various degrees of impact are involved in such definitions. combination impact of all the effective parameters is to be figured out in order to come up w...

tehran shomal highway passes through alborz mountains with a tunnel length of 6400 meters. there are two main tunnels. a full three-dimensional (3d) numerical analysis coupled with elasto-plastic material models was conducted on the inclined access tunnel. bending moment, axial force and the lining displacements due to the internal forces applied on the shotcrete lining are calculated. axial fo...