Results 101 to 110 of about 6,935 (243)

Locality and causality properties of light cone string field theory [PDF]

, 2004
The recent discovery of a new maximally supersymmetric background for the type IIB superstring theory has revived the interest in light cone string field theory.
Kyritisis, Konstantinos
core  

Unexpected Promotion of Bone Regeneration by Inhibition of BMPR1A‐Mediated BMP Signalling

Cell Proliferation, EarlyView.
BMPR1A downregulation reduces ID1, releases TCF3 to activate GNG4‐PI3K‐AKT signalling, thereby promoting OPC proliferation and bone regeneration. ABSTRACT Bone morphogenetic protein (BMP) signalling plays a pivotal role in bone regeneration by regulating osteoprogenitor cell (OPC) function, and BMPs have been widely used in clinical treatment. However,
Zihao Zhou, Yun Zhai, Xiaochen Liu, Jiaojiao Shao, Jiani Zhou, Zhaoyang Li, Jiale He, Shuxian Lin, Qi Zhang   +8 more
wiley   +1 more source

Buckling and dynamic analysis of drill strings for core sampling [PDF]

, 1996
This supporting document presents buckling and dynamic stability analyses of the drill strings used for core sampling. The results of the drill string analyses provide limiting operating axial loads and rotational speeds to prevent drill string failure, instability and drill bit overheating during core sampling. The recommended loads and speeds provide
openaire   +2 more sources

Collagen Type VI Alpha 1 as a Regulator of Redox Homeostasis in Antioxidant‐Enhanced Osteogenesis of Dental Stem Cells

Cell Proliferation, EarlyView.
Under physiological conditions, NAC activates the PI3K‐AKT‐COL6A1 axis to sustain redox balance and enhance osteogenesis. COL6A1 deficiency, however, compromises this axis, inducing oxidative stress and impairing NAC's osteogenic efficacy. ABSTRACT Alveolar bone injury represents a prevalent clinical challenge in dentistry, for which stem cell‐based ...
Zhaosong Meng, Jiacheng Liu, Yue Zhang, Ruimeng Yang, Jingyi Zhang, Haosun Yang, Zheng Wang, Ran Wei, Zhe Li, Shuling Guo, Lizhi Hu, Lei Sui   +11 more
wiley   +1 more source

Backstepping adaptive sliding mode control based on a time-varying barrier function for the suppressing stick-slip vibrations

Open Engineering
Torsional vibrations in lumped drill strings pose a significant challenge in oil and natural gas exploration drilling, often leading to detrimental phenomena such as stick-slip.
Tuama Dina Hameed, Al-Samarraie Shibly Ahmed, Mohd Ghazali Mohamad Hazwan, Rahiman Wan   +3 more
doaj   +1 more source

A REVIEW OF DRILL STRING DYNAMICS AND MODELING TECHNIQUES

Facta Universitatis, Series: Automatic Control and Robotics
The complex dynamics of drill strings under various vibration modes during drilling operations present significant challenges to the oil and gas industry due to the high costs associated with oil well drilling. This analytical study aims to provide a comprehensive overview of the most important and widely used mathematical modeling tools and techniques
openaire   +1 more source

Axial-torsional nonlinear vibration of bottom hole assembly in the air drilling technology

Petroleum
The safety and efficiency of drilling engineering are greatly impeded by destructive vibrations of drill string in air drilling, such as stick-slip, bit-bounce and their coupled vibrations. To avoid or suppress these vibrations improving the stability of
Shujie Ding, Pan Fang, Gao Li, Junan Lu, Yanmin Wang, Yang Li, Yutian Han, Dong Xiao   +7 more
doaj   +1 more source

A large-D Weyl invariant string model in anti-de sitter space [PDF]

, 2002
In this thesis we present a novel scheme for calculating the bosonic string partition function on certain curved backgrounds related to Anti-de Sitter [AdS] space.
Davies, Ian James
core  

Drill Pipe Dynamic Measurements Provide Valuable Insight Into Drill String Dysfunctions

, 2011
Recently the oil and gas drilling industry has become increasingly interested in drilling dynamics and vibration as a cause of reduced drilling performance, downhole tool and drill string failures. Historically, vibration data has been captured by an MWD
Ryan Graham, Andrew D. Craig, Constantijn Raap   +2 more
core   +1 more source

Involvement in daily life activities from the perspectives of children and young people with childhood‐onset disabilities: A scoping review

Developmental Medicine &Child Neurology, EarlyView.
This scoping review aimed to understand the construct ‘involvement’ in daily life activities from the perspective of children and young people with childhood‐onset disabilities. We identified six conceptual ideas, including a continuum of inner dedication or investment in‐the‐moment, and five others reflecting how children and young people process ...
Vera C Kaelin, Kinga Quaaden, Helena Lindgren, Mats Granlund, Christine Imms   +4 more
wiley   +1 more source