Results 61 to 70 of about 22,977 (217)

State-Dependent Delay and Drill-String Dynamics

, 2017
In this work, stability analysis carried out with a reduced-order model of a drill string is presented. This model, which is nonlinear in nature and contains a state-dependent delay, is used to study coupled axial and torsion dynamics of the system.
Xie Zheng, B. Balachandran
semanticscholar   +1 more source

Topographic and Climatic Determinants of Soil Organic Carbon Across Landscapes: A Meta‐Analysis

Land Degradation &Development, EarlyView.
ABSTRACT The soil is the greatest natural store of organic carbon, holding between 1500 to 1550 Pg C of organic carbon at the top 100 cm of the soil globally—roughly twice the carbon pool in the atmosphere. The spatial distribution of this stock is controlled by a complex chain of controls: topographic position regulates the hydrological redistribution,
Vishal Sharma, Syed Hujjat ul Baligah, Tajamul Islam Shah, Shahid Shuja Shafai, Owais Bashir, Syed Sheraz Madhi, S. Naresh Kumar, Ayyandar Arunachalam, Shabir Ahmed Bangroo   +8 more
wiley   +1 more source

Fluid–Structure Interaction Study in Unconventional Energy Horizontal Wells Driven by Recursive Algorithm and MPS Method

Applied Sciences
With the unconventional energy sector (e.g., shale gas) increasingly focused on precision drilling and cost-effective extraction, slim-hole horizontal well technology is gaining prominence.
Xikun Gao, Dajun Zhao, Yi Zhang, Yong Chen, Zhanzhao Gao, Xiaojiao Zhang, Shengda Wang   +6 more
doaj   +1 more source

Internal Structure, Kinematics, and Prehistory of Frozen Debris Lobe‐A (FDL‐A), Brooks Range, Alaska

Permafrost and Periglacial Processes, EarlyView.
ABSTRACT Frozen Debris Lobe‐A (FDL‐A)—one of hundreds of FDLs in the Brooks Range of northern Alaska—is a slow‐moving landslide in permafrost that has been the subject of research since 2008 due to its close proximity to the Dalton Highway. Here, we synthesize more than a decade's worth of climate and surface measurements of monitored FDLs, and the ...
Margaret M. Darrow, Esther L. Babcock, Ben A. Leshchinsky   +2 more
wiley   +1 more source

Reaming While Drilling Drillstring Structure Optimization and Application Performance Evaluation

Shiyou jixie, 2016
The reaming tool BHA is the most important controllable factor during reaming while drilling operations,whereas the irrational drill string structure could lead to intensified drill string vibration.In view of this,the drill string-formation finite ...
Zhang Qiang, Fu Jianhong, Li Haoran
doaj  

CFD Analysis of Pressure Losses and Deposition Velocities in Horizontal Annuli

International Journal of Chemical Engineering, 2019
Estimation of pressure losses and deposition velocities is vital in the hydraulic design of annular drill holes in the petroleum industry. The present study investigates the effects of fluid velocity, fluid type, particle size, particle concentration ...
Rasel A. Sultan, Mohammad Azizur Rahman, Sayeed Rushd, Sohrab Zendehboudi, Vassilios C. Kelessidis   +4 more
doaj   +1 more source

Innovative 3D‐bioprinted microfibers in calcium phosphate cement platform with Nell‐1 to activate nerve‐bone axis for synergistic bone, vasculature, and nanofibrous nerve regeneration

Smart Molecules, EarlyView.
A 3D‐bioprinted platform with stem cells activates “nerve‐bone” signaling by enabling the spatiotemporal delivery of Nell‐1. This activation enhances neurovascular and bone regeneration through the CYFIP1 cascade. In rat calvarial defects, the platform doubled bone regeneration and nerve repair and tripled vascular density, resulting in superior ...
Minjia Zhu, Xinyi Li, Jingyi Li, Kan Yu, Zixiang Dai, Le Xiao, Qinrou Zhang, Zihan Jia, Qingchen Qiao, Zeqing Zhao, Ke Zhang, Yuxing Bai   +11 more
wiley   +1 more source

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

Modeling and experimental identification of torsional drill string dynamics under uncertainties

, 2018
This D.Sc. thesis proposes new perspectives for modeling drill string torsional dynamics under uncertainties. This work develops a novel stochastic hysteretic (nonreversible) bit-rock interaction model.
Fabio Real
semanticscholar   +1 more source

Validation of Aortic Blood Flow Simulations During Extracorporeal Circulation Using Phase Contrast Magnetic Resonance Imaging

Artificial Organs, EarlyView.
This is the first study assessing in vivo blood flow profiles during extracorporeal circulation (ECC) scenarios. Magnetic resonance imaging data served for the calibration of computational fluid dynamics algorithms, enabling accurate replication of the hemodynamic conditions.
Anna Kathrin Assmann, Sinje Reimers, Jonah S. Schrauder, Lei Qu, Xiangge Yin, Amir Moussavi, Artur Lichtenberg, Susann Boretius, Michael Neidlin, Alexander Assmann   +9 more
wiley   +1 more source