Results 91 to 100 of about 4,494 (274)

EXPERIMENTAL AND NUMERICAL STUDIES OF DRILL-STRING DYNAMICS [PDF]

open access: yes, 2011
A drill string is the transmission component of rotary drill-rig system used for mining petroleum and natural gas resources. The drill-string system is essentially a long slender structure whose length can be in kilometers. Additionally, the drill-string
Liao, Chien-Min
core  

Drill-String Torsional Vibration Suppression Using GA Optimized Controllers

open access: yes, 2009
Failure of drill-strings is very costly in terms of money and time and occurs more frequently than oil companies would like to see. There are many reasons for drill-string failure, such as vibration, fatigue, and buckling.
Y.L. Abdel-Magid   +2 more
core   +1 more source

Drill string torsional vibrations modeling with dynamic drill pipe properties measurement and field validation

open access: yes, 2022
This paper aims to present the drill string torsional dynamics through a lumped parameter modeling using the basic physical notions with continuous measurement of drill pipe mechanical properties (inertia, damping, and stiffness).
Youcefi, Mohamed Riad   +2 more
core   +1 more source

Preharvest supplemental lighting enhances productivity and modulates postharvest quality in hydroponically grown Apulian unripe melon ‘Scopatizzo’ (Cucumis melo L.)

open access: yesJournal of the Science of Food and Agriculture, EarlyView.
Abstract BACKGROUND Preharvest light management is increasingly used to enhance yield and fruit quality in soilless systems, yet its effects on unripe melon fruits remain poorly understood. This study evaluated the impact of supplemental red–blue light‐emitting diode (LED) lighting applied during cultivation in a closed‐cycle hydroponic system on ...
Onofrio Davide Palmitessa   +7 more
wiley   +1 more source

Acoustical properties of drill strings

open access: yesThe 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

Test report for drill string seal pressure test [PDF]

open access: yes, 1996
A basic question was asked concerning the drill string which is used in rotary Mode coring operations: ``...what is the volume leak rate loss in a drill rod string under varying condiditons of the joint boxes and pins being either dry or coated with ...
McCormick, J.F.
core   +1 more source

Automated data extraction for systematic reviews using GPT‐5.2 and Google Gemini Pro 3: A dual‐large language model approach in orthopaedic research

open access: yesKnee Surgery, Sports Traumatology, Arthroscopy, EarlyView.
Abstract Purpose To evaluate the accuracy, agreement, and efficiency of a dual‐large language model (LLM) approach using Generative Pre‐Trained Transformer 5.2 (GPT‐5.2) and Google Gemini 3 Pro for automated data extraction in orthopaedic systematic reviews.
Prushoth Vivekanantha   +6 more
wiley   +1 more source

Stick-Slip Vibration Suppression in Drill String Using Observer-Based LQG Controller. [PDF]

open access: yesSensors (Basel), 2022
Riane R   +4 more
europepmc   +1 more source

BHA and Drill String Fundamentals: Technology Training for Beginners

open access: yes, 2010
In the industry, there is an abundance of highly technical engineer-based training available on drill string design, but a different approach is required for employees that simply need a basic understanding of drill string principles.
Sarah Wakefield, Katrina Pigusch
core   +1 more source

Continental accumulation of fads2 copy numbers allows sticklebacks to thrive across a diversity of nutritional landscapes

open access: yesOikos, EarlyView.
Nutrients, including vital organic compounds, vary in availability across ecosystems, with the potential to act as a source of selection for traits that increase nutrient acquisition and biosynthesis. Compared to freshwaters, marine ecosystems are richer in the omega‐3 long‐chain polyunsaturated fatty acid (n‐3 LC‐PUFA) docosahexaenoic acid (DHA ...
Cornelia W. Twining   +12 more
wiley   +1 more source

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