Factors underlying biological and socio-biological states include a complex interplay of several biological, behavioral, economic, and social factors. A reductionist view usually assesses the interplay of factors using a “drill-down” approach by examining smaller parts of a system under the paradigm that these parts, when fit-together, will translate to a fully functional whole. However, often ...

Article presents results of study on possibility of increasing the efficiency of drilling directional straight sections of wells using screw downhole motors (SDM) with a combined method of drilling with rotation of drilling string (DS). Goal is to ensure steady-state operation of SDM with simultaneous rotation of DS by reducing the amplitude of oscillations with adjusting the parameters of dril...

Deep hole drilling methods are used for drilling holes with a high length-to-diameter ratio, good surface finish and straightness. Due to the slender tool-boring bar combination needed for producing holes with a high length-to-diameter ratio, the process is susceptible to dynamic disturbances. These disturbances can be classified as chatter vibration or spiralling. The work presented in this pa...

In this paper, we apply recent results on disturbance rejection in the interior domain of a class of 2 × 2 linear hyperbolic systems of partial differential equations to the problem of rejecting heave-induced pressure fluctuations at the casing shoe in managed pressure drilling. We show that a PDE model of the drilling dynamics belongs to this class of systems, and derive both state feedback an...

In drilling of composite laminates, it is important to minimize or reduce occurrences of delaminations. In particular, a peel-up delamination at entrance and push-out delamination at exit are common. Delaminations may be avoided by regulating the drill thrust force can be controlled by adjusting the feedrate of the drill. Dynamics involved in drilling of composite laminates is time varying and ...

BTA 1 deep hole drilling is a method for producing precision bores with high length to diameter ratios. The long and slender tools feature low torsional and bending stiffness. This may lead to undesirable dynamic disturbances of the machining process usually classified as either chatter vibration or spiralling. Prediction and identification of the causes of these process failures is important f...

ANDRILL completed its first season in 2006-07 drilling AND-1B through the McMurdo Ice Shelf (MIS) to a depth of 1,285m below the sea floor, a record for Antarctic margin drilling, with 99% recovery. The alternating glacial-interglacial sediment packages interbedded with volcanics provide a uniquely detailed record of Antarctic glacial and climatic change through the Neogene. This paper summariz...

Deep hole drilling methods are used for producing holes with a high length-to-diameter ratio, good surface finish and straightness. The process is subject to dynamic disturbances that is classified as either chatter vibration or spiralling. In this work, nonlinear time series modeling is used to setup an on-line modeling approach of the time varying dynamics of the process. An on-line monitorin...