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Subcapsular renal hematoma (SRH) is a challenging condition, which may jeopardize kidney function or constitute a life-threatening event. This is particularly true in single-kidney patients, such as kidney-transplant recipients. SRH may exert an excessive pressure on the surrounding parenchyma, thus resulting in hypoperfusion and ischemia, with high risk of acute kidney failure and graft loss. Moreover, SRH may precede an overt renal rupture with subsequent hemorrhage and hemodynamic instability. The indication to an interventional management for this condition is still a matter of debate, with some authors advocating the high possibilities of spontaneous resolution and others advocating the high-risk of graft loss and even internal bleeding in case of overt renal rupture. Herein, we report the case of a 51-year-old simultaneous pancreas-kidney transplantation recipient who presented a SRH following a mild trauma. The therapeutic choices were carefully balanced on the specific case, and the conservative management proved successful.

Gearboxes usually run under fluctuating load conditions during service, however most of papers available in the literature describe models of gearboxes under stationary load conditions. Main task of published papers is fault modeling for their detection. Considering real situation from industry, the assumption of stationarity of load conditions cannot be longer kept. Vibration signals issued from monitoring in maintenance operations differ from mentioned models (due to load non-stationarity) and may be difficult to analyze which lead to erroneous diagnosis of the system. The objective of this paper is to study the influence of time varying load conditions on a gearbox dynamic behavior. To investigate this, a simple spur gear system without defects is modeled. It is subjected to a time varying load. The speed-torque characteristic of the driving motor is considered. The load variation induces speed variation, which causes a variation in the gearmesh stiffness period. Computer simulation shows deep amplitude modulations with sidebands that don't differ from those obtained when there is a defective tooth. In order to put in evidence the time varying load effects, Short Time Fourier Transform and then Smoothed Wigner-Ville distribution are used. Results show that the last one is well suited for the studied case.

The paper deals with mathematical modelling and computer simulation of a gearbox system. Results of computer simulation show new possibilities of extended interpretation of a diagnostic acceleration signal if signal is obtained by synchronous summation. Four groups of factors: design, production technology, operation, change of gear condition are discussed. Results of computer simulations give the relation between inter-teeth forces and vibration (acceleration, velocity). Some results of computer simulations are referred to the results obtained in rig measurements and in field practice. The paper shows a way of increasing the expert's knowledge on the diagnostic signal, which is generated by a gearbox system, on a base of mathematical modelling and computer simulation.