Results 61 to 70 of about 178,633 (301)

Analysis of the effects of torsional impact tools on drill string stick–slip vibration

open access: yesEnergy Exploration & Exploitation
Torsional impactor is widely used in deep and ultra-deep wells because it can suppress stick–slip vibration and increase ROP. As the direct factor affecting torsional impactor effect, it's working parameters study is still not sufficient.
Chaoyi She   +5 more
doaj   +1 more source

Experimental Study on Axial Impact Mitigating Stick-Slip Vibration with a PDC Bit

open access: yesShock and Vibration, 2021
Stick-slip vibration reduces the drilling rate of penetration, causes early wear of bits, and threatens the safety of downhole tools. Therefore, it is necessary to study suppression methods of stick-slip vibration to achieve efficient and safe drilling ...
Yong Wang   +7 more
doaj   +1 more source

Stick-slip suppression and speed tuning for a drill-string system via proportional-derivative control

open access: yes, 2020
This paper studies the problems of stick-slip mitigation and speed tuning for a lumped-parameter drill-string system by using a proportional-derivative feedback controller via path-following analysis.
Y Liu (4702669)   +4 more
core  

Stick and Slip Stick and Slip

open access: yes, 1961
When two substances rub against each other, they frequently stick and then slip. The phenomenon accounts for the squeak of bearings, the music of violins and many other sounds of our daily experience.
Ernest Rabinowicz
core   +1 more source

Affecting the Properties of Copper–Graphene Electroconductive Composite by Severe Plastic Deformation

open access: yesAdvanced Engineering Materials, EarlyView.
Copper‐based composites enhanced with carbon feature convenient mechanical properties and favorable electric conductivity. Processing via deformation and thermomechanical treatments can introduce advantageous microstructures further enhancing their performance. Herein, copper–graphene powder‐based composites are directly consolidated via rotary swaging
Radim Kocich   +3 more
wiley   +1 more source

Fatigue Crack Initiation and Growth in Nanocrystalline Ni at Multiple Length‐Scales

open access: yesAdvanced Engineering Materials, EarlyView.
Overview of miniaturized in situ SEM fatigue setup and resultant fatigue crack growth data for nanocrystalline Ni. The presented study focuses on the analysis of fatigue crack growth rate (FCGR) in focused ion beam‐notched microcantilevers prepared from nanocrystalline (NC) Ni as a model material.
Igor Moravcik   +7 more
wiley   +1 more source

Dynamic Spectral Analysis of the Stick-Slip Effects in “Oral” Tribology Measurements

open access: yes, 2016
“Oral” tribology, associated with oral surface movement and friction, is a new tool to understand complex texture attributes such as “creamy, oily and astringent” which could not be successfully characterized by bulk texture analysis or by rheology ...
Upadhyay, Rutuja   +3 more
core   +1 more source

Creep‐Induced Microstructural Evolution in an A2‐B2 Superalloy

open access: yesAdvanced Engineering Materials, EarlyView.
A 27.3Ta‐27.3Mo‐27.3Ti‐8Cr‐10Al (at.%) refractory high‐entropy alloy with precipitation‐strengthened A2‐B2 microstructure was studied by creep tests at 1030°C, which demonstrate a transition in deformation mechanisms in the range of 100–150 MPa applied stress. This is associated with changes in dislocation–precipitate interactions. Relevant deformation
Liu Yang   +10 more
wiley   +1 more source

Workflow for Design of Experiments‐Based Modeling of Species Transport and Growth Kinetics in GaN Hydride Vapor Phase Epitaxy

open access: yesAdvanced Engineering Materials, EarlyView.
A novel workflow for investigating hydride vapor phase epitaxy for GaN bulk crystal growth is proposed. It combines Design of experiments (DoE) with physical simulations of mass transport and crystal growth kinetics, serving as an intermediate step between DoE and experiments.
J. Tomkovič   +7 more
wiley   +1 more source

Stick-Slip Transition at the Nanometer Scale

open access: yesPhysical Review Letters, 2003
We report the first observation of a stick-slip transition of surfactant solution flow through nanopores. From the experimental data, we were able to determine both the slip length and the critical wall shear stress from which slip occurs. Whereas the latter is found to increase linearly with the concentration, the former remains constant and ...
Cheikh, C. (author), Koper, G. (author)
openaire   +4 more sources

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