Results 81 to 90 of about 3,418,514 (199)

Research on Mechanism of Stick-Slip Vibration Induced by Friction between Drill String and Borehole Wall in Horizontal Well

Shiyou jixie, 2021
The stick-slip vibration of the horizontal well drill string system seriously threatens the safety of downhole drill strings and tools, reduces the drilling efficiency of the horizontal section, making the drill bit fail prematurely.
Zhu Jieran, Zou Deyong, Li Guangquan, Yang Ningning, Yang Quanjin, Lin Wei   +5 more
doaj  

Toward an Indigenous Curatorial Practice: Learning From Tłı̨chǫ Metaphors of Care to Establish Principles of Curation

American Anthropologist, EarlyView.
ABSTRACT The displacement of items of cultural heritage from Indigenous communities is continually perpetuated through their appropriation into collection systems that are inappropriate to Indigenous laws and customs. This paper presents the efforts of the Tłı̨chǫ Government (TG) to address such issues by creating a system that is rooted within its ...
Rebecca L. Bourgeois, Karen Gelderman
wiley   +1 more source

ReTrace: Interactive Visualizations for Reasoning Traces of Large Reasoning Models

Computer Graphics Forum, EarlyView.
Abstract Recent advances in Large Language Models have led to Large Reasoning Models, which produce step‐by‐step reasoning traces. Such traces may offer insight into how models think, improving explainability and clarifying the underlying process. These traces, however, are often verbose and complex, making them cognitively demanding to comprehend ...
L. Felder, J. Miller, M. Wallinger, S. G. Kobourov, C. Chen   +4 more
wiley   +1 more source

Using Targeted Energy Transfer to Stabilize Drill-string Systems [PDF]

, 2007
Torsional vibration of the drill strings used in drilling oil and gas wells arises from a complex interaction of the dynamics of the drilling structure with speed-dependent effective rock-cutting forces.
Golinval, J.C., Bergman, L.A., Vakakis, AF, Vakakis, A.F., Vakakis, Alexander F., Golinval, JC, Viguie, R., Viguié, Régis, McFarland, DM, Wouw, van de, N., Kerschen, G., Viguie, R, Kerschen, G, Van De Wouw, N, Bergman, LA, McFarland, D.M., Bergman, Lawrence A., Kerschen, Gaëtan, van de Wouw, N., Golinval, Jean-Claude   +19 more
core  

Effects of axial impact load on the dynamics of an oilwell drillstring

Advances in Mechanical Engineering, 2019
This article studies the dynamics of oilwell drillstring under large and small axial impact loads. For the case of large impact load, the drillstring is regarded as a continuous bar under the impact load of a falling mass, and the energy conservation ...
Liping Tang, Xiaohua Zhu, Hongzhi Lin
doaj   +1 more source

Effects of restoration practices on biodiversity in temperate and boreal forests

Conservation Biology, EarlyView.
Abstract Several restoration practices are used to mitigate and compensate for the negative effects of large‐scale forestry on biodiversity in temperate and boreal forests. A comprehensive synthesis of the benefits of these practices across taxa is missing. We conducted a systematic review and meta‐analysis on this topic.
Malin Tälle, Thomas Ranius, Julia Koricheva   +2 more
wiley   +1 more source

Drill-string dynamics coupled with the drilling fluid dynamics

, 2009
International audienceA drill-string is a slender structure that turns and drills into the rock in search of oil. A numerical model is developed using the Timoshenko beam theory and approximated by means of the Finite Element Method. The aim this work is
Ritto, T.G., Soize, Christian, Sampaio, R.   +2 more
core   +3 more sources

Backstepping adaptive sliding mode control based on a time-varying barrier function for the suppressing stick-slip vibrations

Open Engineering
Torsional vibrations in lumped drill strings pose a significant challenge in oil and natural gas exploration drilling, often leading to detrimental phenomena such as stick-slip.
Tuama Dina Hameed, Al-Samarraie Shibly Ahmed, Mohd Ghazali Mohamad Hazwan, Rahiman Wan   +3 more
doaj   +1 more source

Pre‐Task Explicit Instruction, Input Modality, and Working Memory in L2 Oral Self‐Repair

International Journal of Applied Linguistics, EarlyView.
ABSTRACT Despite the central role of tasks in language education and ensuing research documenting how task‐related variables might affect language performance and learning, it remains unclear whether pre‐task explicit instruction, input modality, and working memory (WM) influence how learners monitor and repair grammatical structures in real‐time ...
Reza Yadollahpour, Mostafa Pourhaji, Michael Sadeghi   +2 more
wiley   +1 more source

Climate change impacts on fish in the Baltic Sea

Journal of Fish Biology, EarlyView.
Abstract The Baltic Sea is a marginal sea with strong abiotic gradients harbouring fish of both marine and freshwater origin. Here we review the empirical evidence for how changes in climate variables have impacted different fish and fish communities in the Baltic Sea.
Örjan Östman, Meri Kallasvuo, Sanna Kuningas, Antti Lappalainen, Noora Mustamäki, Rahmat Naddafi, Lauri Saks, Jens Olsson   +7 more
wiley   +1 more source