Results 81 to 90 of about 6,935 (243)

Bound by blood and bloodshed: Sibling ties and participation in genocidal violence

Criminology, EarlyView.
Abstract Focusing on the 1994 genocide in Rwanda, we examine how sibling relationships—one of the most salient familial bonds—influence individual engagement in violence during mass atrocity. Drawing on an adaptation of differential association and social learning theories for contexts of mass atrocity, we analyze a novel dataset linking over 300,000 ...
Jack G. R. Wippell, Hollie Nyseth Nzitatira, Jared F. Edgerton, Evelyn Gertz   +3 more
wiley   +1 more source

Improved stiff string torque and drag prediction using a computationally efficient contact algorithm

Mathematical and Computer Modelling of Dynamical Systems
Due to the intermittent contact with the wellbore, determining torque and drag for deviated wells is difficult. Most models have ignored drill string stiffness and assumed continual contact to simplify derivation.
Sampath Liyanarachchi, Geoff Rideout
doaj   +1 more source

Qualification of a computer program for drill string dynamics

, 1985
A four point plan for the qualification of the GEODYN drill string dynamics computer program is described. The qualification plan investigates both modal response and transient response of a short drill string subjected to simulated cutting loads applied
Carne, T. G., Caskey, B. C., Stone, C. M.   +2 more
core  

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

Influences of Excitation Force Forms of the Hydraulic Oscillator on Drag Reduction Efficiency

Shiyou jixie, 2023
The excitation force forms of the hydraulic oscillator have been rarely reported.Considering the nonlinear effect of frictional forces, a dynamics model of the drill string equipped with the hydraulic oscillator was built by introducing the initial ...
Shi Xiaolei, Huang Wenjun, Gao Deli
doaj  

Aspects of brane world-volume dynamics in string theory

, 2012
PhDThis thesis investigates the non-abelian dynamics of D-Brane systems in String Theory, specifically focussing on the fate of the open string Tachyon.
Tallarita, Gianni
core  

Understanding and Eliminating Drill String Twist-Offs by the Collection of High Frequency Dynamics Data

, 2011
Drill string twist-offs are an expensive problem to the oil and gas drilling industry. With ever increasing rig and operating costs, there is an increased focus to avoid twist-off related expenses, such as: costs associated with time required to trip out
Daniel Perez, Constantijn Raap, Andrew Craig   +2 more
core   +1 more source

Assessing the Vulnerability of an Inuit Archaeological Site in a Changing Periglacial Environment: A Novel Multimethod Geophysical Approach in Arctic Geoarchaeology

Archaeometry, EarlyView.
ABSTRACT With northern regions warming at twice the global rate, assessing the state of archaeological sites in these areas is critically important. In this study, we used a multimethod geophysical approach (ERT, GPR, and EMI) to characterize the current geocryological conditions of an Inuit archaeological site on South Aulatsivik Island (Labrador ...
Rachel Labrie, Dominique Todisco, Najat Bhiry, Cécile Finco, Héloïg Barbel Le Page, Armelle Couillet   +5 more
wiley   +1 more source

Study on Fatigue Life of BHA based on Drill String Dynamics

Shiyou jixie, 2022
The bottom hole assembly(BHA)is prone to fatigue failure due to long-term severe vibration in the wellbore.Most studies use the differential equation to calculate the fatigue life of BHA,which has a large difference from the actual working conditions on ...
Mao Liangjie, Gan Lunke, Xing Xuesong, Li Juan   +3 more
doaj  

Underreamer mechanics

, 2009
In the oil and gas industry, an underreamer is a tool used to extend and enlarge the diameter of a previously-drilled bore. The problem proposed to the Study Group is to obtain appropriate mathematical models of underreamer dynamics, in forms that will ...
Coskun, Erhan, Richardson, Giles, Lorenz, Maike, Jones, Marvin, Barton, David, Hall, Cameron, Lacey, Andrew, Maringer, Johannes, Please, Colin   +8 more
core