Results 121 to 130 of about 236,174 (283)

Study on Mechanism of Stick–Slip Vibration Based on Torque Characteristics of PDC Bit

Applied Sciences
Stick–slip vibration (SV) of drill string systems is the main cause of fatigue failure of PDC bits under complex drilling conditions. Exploring its mechanism is helpful for identifying the causes of bit failure and developing preventive measures to ...
Lijun Li, Chunliang Zhang, Aixuan Wu
doaj   +1 more source

Acoustical properties of drill strings

The Journal of the Acoustical Society of America, 1989
The recovery of petrochemical and geothermal resources requires extensive drilling of wells to increasingly greater depths. Real-time collection and telemetry of data about the drilling process while it occurs thousands of feet below the surface is an effective way of improving the efficiency of drilling operations.
openaire   +2 more sources

Integrating large mammalian herbivores into Dynamic Global Vegetation Models: Status and next steps

Functional Ecology, EarlyView.
Read the free Plain Language Summary for this article on the Journal blog. Abstract Zoogeochemistry, the study of how animals influence elemental cycling within ecosystems, bridges the fields of zoology, ecology and biogeochemistry. Yet, most terrestrial ecosystem models, especially Dynamic Global Vegetation Models (DGVMs), remain largely plant‐centric
Yue Cheng, Joanne Alice O'Keeffe, Andrew J. Abraham, Jesper Riis Christiansen, Frederik Nygaard Philipsen, Klaus Steenberg Larsen, Fabio Berzaghi, Carsten W. Mueller, Lars Vesterdal, Jeppe A. Kristensen, Elizabeth Le Roux   +10 more
wiley   +1 more source

Test on Bending Fatigue Damage of Full-size Drill String

Shiyou jixie, 2017
In the past, the study on the fatigue damage of drill string was mostly modeling or small-scale test, which could not accurately represent the fatigue damage of full-bore drill string.Based on the four-point bending fatigue test, taking the full-size ...
Cheng Caixia, Fan Jianchun, Hu Zhibin, Gao Weijun, Wu Jiafeng, Liu Shujie, He Yingming   +6 more
doaj  

Numerical Investigation of the Nonlinear Drill String Dynamics Under Stick–Slip Vibration

Vibration
This paper presents a comprehensive analysis of the influence of rotary table velocity, weight-on-bit, and viscous damping on the drill string stick–slip vibration.
Mohammad Javad Moharrami, Hodjat Shiri, Clóvis de Arruda Martins   +2 more
doaj   +1 more source

125 years of exploration and research at Gough's Cave (Somerset, UK) 125 ans d'exploration et de recherches à Gough's Cave (Somerset, Royaume‐Uni)

Journal of the Royal Anthropological Institute, EarlyView.
Our understanding of the recolonization of northwest Europe in the period leading up to the Lateglacial Interstadial relies heavily on discoveries from Gough's Cave (Somerset, UK). Gough's Cave is the richest Late Upper Palaeolithic site in the British Isles, yielding an exceptional array of human remains, stone and organic artefacts, and butchered ...
Silvia M. Bello, Mark D. Lewis, Simon A. Parfitt   +2 more
wiley   +1 more source

And then there was us Et puis nous sommes apparus

Journal of the Royal Anthropological Institute, EarlyView.
In 1987, the academic conference ‘Origins and Dispersals of Modern Humans: Behavioural and Biological Perspectives’ was held in Cambridge, UK. Subsequently referred to as the ‘Human Revolution’ conference, this meeting brought together the most prominent academics working in the field of human origins, including archaeologists and palaeoanthropologists,
Emma E. Bird, Julia Galway‐Witham, Chris Stringer   +2 more
wiley   +1 more source

Equal before time: on the sensory suspension of accumulated time in Sichuan, China Égaux devant le temps : suspension sensorielle du temps accumulé au Sichuan (Chine)

Journal of the Royal Anthropological Institute, EarlyView.
Food and alcohol indulgence, along with tea‐drinking, gambling, and gossip, are integral to a characteristically Sichuanese ethos of ‘life enjoyment’ (xiangshou shenghuo). Beyond mere pleasure, sensory, ludic, and comic experiences temporarily strip participants of both their formal and subjective qualities.
Angel Nayden
wiley   +1 more source

A Tribunal Only in Name: Anarchic Sensibilities at the International Tribunal on Crimes Against Women, 1976

History, EarlyView.
Abstract In March 1976, around 2000 women from forty countries arrived at the Palais des Congrès in Brussels to participate in the first International Tribunal on Crimes Against Women. Explicitly positioning themselves against the United Nations‐led ‘International Year of the Woman’, the organizers and participants of the tribunal proclaimed a global ...
NIVEDITA JOON
wiley   +1 more source

Effect of Bit Type on Reactive Torque and Consequent Tool-face-control Anomalies

Shiyou jixie, 2017
In sliding drilling with bend house mud motor, given the same WOB, the reactive torque is greater and the directional drilling is more difficult if the drill bit is more aggressive.
Xu Lihui
doaj