The motion of drill strings is modeled in the drilling geotechnological wells mining industry by Lumped-Parameter Method (LPM). This method widely used structural mechanics and most justified modeling dynamic systems with a variable structure. On example horizontal wells, longitudinal vibrations string static compressive load at left end are considered [1]. contact interaction borehole walls in...

With the widespread application of junction transistors in switching applications, the need for a general method of analysis useful in the region of collector voltage saturation has become apparent. Linear equivalent circuits using lumped elements have long been used for small signal calculations of normally-biased transistors, but a comparable method for saturated transistors has been lacking....

This work aims at studying the nonlinear dynamics of drill strings using lumped-parameter method (LPM). The study is based on good consistency results test problem where model longitudinal vibrations a horizontal string with static compressive load left end considered. In this paper, applied to discretize linear and models lateral vertical under effect supersonic gas flow. obtained are verified...

The aim of this paper is to determine the stress levels at the end of a long slender shaft such as a drilling assembly used in the oil or gas industry using a mathematical model in real-time. The torsional deflection experienced by this type of drilling shaft (about 4 KM length and 20 cm diameter hollow shaft with a thickness of 1 cm) can only be determined using a distributed modeling techniqu...

The glucose metabolic rate of the human brain can be measured with labeled deoxyglucose, using positron emission tomography, provided certain conditions are fulfilled. The original method assumed irreversible trapping of deoxyglucose metabolites in brain during the experimental period, and it further requires that a conversion factor between deoxyglucose and glucose, the "lumped constant," be k...