Hypotheses suggesting that hip joints which develop osteoarthritis are congruent, have a single area of peak pressure, and have peak pressure which exceeds normal values were tested. Of 100 hip joints examined on necropsy; two showed an early stage of osteoarthritis and the geometry and pressure distribution under load were assessed in these joints. One joint was congruent, in agreement with th...

This article introduces a new method to represent bone surface geometry for simulations of joint contact. The method uses the inner product of two basis functions to provide a mathematical representation of the joint surfaces. This method guarantees a continuous transition in the direction of the surface normals, an important property for computation of joint contact. Our formulation handles ex...

The human knee joint has a three dimensional geometry with multiple body articulations that produce complex mechanical responses under loads that occur in everyday life and sports activities. To produce the necessary joint compliance and stability for optimal daily function various menisci and ligaments are present while muscle forces are used to this effect. Therefore, knowledge of the complex...

The hip joint is one of the largest weight bearing structures in the human body. While its efficient structure may lend to a lifetime of mobility, abnormal, repetitive loading of the hip is thought to result in osteoarthritis (OA). The etiology of hip OA is unknown however, due to the high loads this joint supports, mechanics have been implicated as the primary factor. Quantifying the relevant ...

N. Ratković, Faculty of Engineering, University of Kragujevac, Kragujevac, Serbia. R. Nikolić, Faculty of Civil Engineering, University of Žilina, Žilina, Slovakia. I. Samardžić, University of Osijek, Mechanical Engineering Faculty in Slavonski Brod, Croatia. Fundamental principles of friction welding of dissimilar steels (high speed and tempering steel) from the aspect of metallurgical and che...

This paper studies the geometry of perspective projection into multiple images and the matching constraints that this induces between the images. The combined projections produce a 3D subspace of the space of combined image coordinates called the joint image. This is a complete projective replica of the 3D world defined entirely in terms of image coordinates, up to an arbitrary choice of certai...

To investigate the parameters of the protein design problem that we are exploring in collaboration with biochemists, we have developed a tool that uses inverse kinematics to support moving small fragments of protein backbone, while respecting biochemists’ desires to “remain in favorable regions of the Ramachandran plot” and “preserve ideal geometry”. By presenting estimates of derivatives in re...