Results 91 to 100 of about 4,548 (230)

Theory of differential inclusions and its application in mechanics

, 2018
The following chapter deals with systems of differential equations with discontinuous right-hand sides. The key question is how to define the solutions of such systems.
A Andronov, A Filippov, A Tolstonogov, AF Filippov, AKh Gelig, AS Poznyak, B Brogliato, BR Andrievsky, C Edwards, C Li, D Dudkowski, E Rabinowicz, E Shokir, F Pfeiffer, F Plestan, FP Bowden, GA Leonov, GA Leonov, GA Leonov, GA Leonov, GA Leonov, GA Leonov, GA Leonov, GA Leonov, GA Leonov, HL Royden, I Burkin, I Goryacheva, I Zelinka, J Bruin De, KC Ludema, M Kiseleva, M Kiseleva, M Kiseleva, MA Aizerman, MA Kiseleva, MA Kiseleva, MF Danca, N Kondrateva, N Kuznetsov, N Mihajlovic, NV Kuznetsov, NV Kuznetsov, NV Kuznetsov, O Vaisberg, P Li, P Painlevé, PE Kloeden, PJ Blau, PT Piiroinen, Q Li, RC Arkin, S Emelyanov, T Wazewski, U Chaudhuri, V Kolesnikov, VG Boltianskii, VI Utkin, VO Bragin, Z Wei, Z Wei, ZT Zhusubaliyev   +61 more
core   +1 more source

Довговічність трубних колон за складного напружено-деформованого стану [PDF]

, 2016
Метою статті є розроблення методу прогнозування довговічності трубних колон, враховуючи як нормальні, так і дотичні напруження в їх поперечному перерізі.
Артим, В. І., Рачкевич, Р. В., Слободян, В. І., Івасів, В. М.   +3 more
core  

Robustness of an Adaptive Output Feedback for an Anti-Damped Boundary Wave PDE in Presence of In-Domain Viscous Damping

, 2016
International audienceThis paper presents a robustness result for the use of a previously developed adaptive output-feedback controller designed for a pure wave PDE.
Bresch-Pietri, Delphine, Prieur, Christophe, Roman, Christophe, Sename, Olivier   +3 more
core   +3 more sources

A method for optimizing and controlling rocking drillstring–assisted slide drilling

Natural Gas Industry B
Rocking the drillstring at the surface during slide drilling is a common method for reducing drag when drilling horizontal wells. However, the current methods for determining the parameters for rocking are insufficient, limiting the widespread use of ...
Yabin Zhang, Jian Lu, Binfeng Guo, Xueying Wang, Feifei Zhang   +4 more
doaj   +1 more source

Thermal Characteristics of Borehole Stability Drilling in Hot Dry Rock. [PDF]

ACS Omega, 2021
Zhu Z, Wang C, Guan Z, Lei W.
europepmc   +1 more source

Stick-slip and Torsional Friction Factors in Inclined Wellbores

MATEC Web of Conferences, 2018
Stick slip is usually considered a phenomenon of bit-rock interaction, but is also often observed in the field with the bit off bottom. In this paper we present a distributed model of a drill string with an along-string Coulomb stiction to investigate ...
Aarsnes Ulf Jakob F., Shor Roman J.
doaj   +1 more source

Vertical-Screw-Auger Conveyer Feeder [PDF]

A conical feeder is attached to a vertically conveying screw auger. The feeder is equipped with scoops and rotated from the surface to force-feed regolith the auger.
Vollmer, Hubert J., Walton, Otis
core   +1 more source

A review of vertical drill-string mathematical modelling

Applications in Engineering Science
This work aims to elucidate the fundamental concepts and approaches for modelling the vertical rotary drilling system and analysing drill string vibrations through a comprehensive literature review.
Jasem M. Kamel, Asan G.A. Muthalif, Abdulazim H. Falah   +2 more
doaj   +1 more source

Mixed Micromax and hematite-based fly ash geopolymer for heavy-weight well cementing. [PDF]

Sci Rep, 2023
Abdelaal A, Elkatatny S.
europepmc   +1 more source

Drillstring Vibration Identification Based on Data Augmentation and Automated Machine Learning

Shiyou jixie
Accurate identification of downhole drillstring vibration is significant for improving drilling efficiency and reducing complex risks. However， traditional vibration identification mechanisms and methods are based on several hypotheses， making them ...
Pan Tao, Song Xianzhi, Liu Muchen, Xiao Shijie, Qin Yonghe, Zhu Zhaopeng, Zhang Chengkai   +6 more
doaj