Results 121 to 130 of about 1,056,070 (342)
MECHANICAL ANALYSIS OF THE DRILL BIT IN THE DUAL CASING SIDETRACKING
Jixie qiangdu, 2016 In the dual casing sidetracking,the oil casing wall,cement ring,technical casing wall and rock formations’ hardness are different,furthermore,in the process of dual casing sidetracking the bit in contact with the oil casing wall,cement ring,technical ...
KONG ChunYan, LIANG Zheng, ZHANG DeRong
doaj
British Educational Research Journal, EarlyView.Abstract Quality in early childhood education and care (ECEC) is a contested concept and has generally been conceptualised by inter‐related indicators such as staff qualifications, educational environment, policy or child‐to‐staff ratios. There has been a more limited emphasis on how young children might perceive and experience quality.
Nikki Fairchild, Éva Mikuska
wiley +1 more source
Numerical simulation of bottomhole flow field of PDC bit in horizontal well
Jin'gangshi yu moliao moju gongchengObjectives: Horizontal wells can effectively improve the economic benefits of shale oil and gas development. However, as the horizontal section extends, the rock debris transport efficiency of the PDC drill bit gradually decreases, which can lead to bit ...
Sai LI +4 more
doaj +1 more source
Rotary ultrasonic machining of rocks: An experimental investigation
Advances in Mechanical Engineering, 2018 Rock drilling is widely used to explore and mine energy resources. It has also been used to extract samples to study the earth’s geological composition and topography and to explore different planets.
PKSC Fernando, Meng Zhang, Zhijian Pei
doaj +1 more source
Listening to Hong Kong children's perspectives through pretend play
British Educational Research Journal, EarlyView.Abstract Quality in early childhood education and care (ECEC) has become an increasing concern in recent years. The issue has been regularly discussed by different stakeholders. However, the rising concern regarding quality in ECEC has not seriously taken into account children's perspectives.
Suzannie K. Y. Leung
wiley +1 more source
Biological Reviews, EarlyView.ABSTRACT The ecology of forests, their losses, and terrestrial wood decomposition dynamics have been intensively studied and reviewed. In the aquatic realm, reviews have concentrated on large wood (LW) in rivers and the transition from freshwater to marine environments in the Pacific Northwest of North America. However, a comprehensive global synthesis
Jon Dickson +9 more
wiley +1 more source
Research status and development trend on wear of impregnated diamond bits
地质科技通报Significance Impregnated diamond bits (IDBs) have been widely used in various hard rock drilling activities, especially deep drilling. Drilling process with IDBs relies on diamond edge wrapped by metal matrices to break the rock formation, which means ...
Longchen DUAN +5 more
doaj +1 more source
Testing of Sealing Elements for FIB Apparatus Designed to Liquidate Open Eruption by Drilling Tools [PDF]
, 2018 Petroleum and natural gas still have their place among the most important resources in many industrial areas. Their global consumption influences an increasing demand on the quality of drilling works and the efficiency ...
Bujok, Petr +4 more
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Biological Reviews, EarlyView.ABSTRACT Effective knowledge of ecological connectivity at sea and at the land–sea interface is key to supporting global policy goals to conserve and restore ocean biodiversity and function. However, a persistent lack of commonality in terminology and understanding around the concept of connectivity in marine ecological studies hampers its integration ...
Audrey M. Darnaude +20 more
wiley +1 more source
Recovery at Morvin: SERPENT final report [PDF]
, 2010 Recovery from disturbance is poorly understood in deep water, but the extent of anthropogenic impacts is becoming increasingly well documented. We used Remotely Operated Vehicles (ROV) to visually assess the change in benthic habitat after exploratory ...
Gates, A.R., Jones, D.O.B.
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